Consulta: subjectFacets:"Model"
Registros recuperados: 127
Data/hora: 13/06/2024 02:44:17

Simulación de la operación de la poza la becerra con fines de preservación de humedales, flora y fauna del Valle de Cuatro Ciénegas.
Provedor de dados: 32
Autores: Paredes Santaella, Andrés.
Se realizaron dos modelos, uno hidrológico y uno dinámico, para simular el comportamiento de la poza La Becerra, en el valle de Cuatro Ciénegas, Coahuila, para identificar el efecto de las extracciones de agua para el riego en la hidrología del humedal El Garabatal. Los modelos se basan en un balance hídrico, el cual está definido por la aplicación del principio de conservación de masas, también conocido como ecuación de la continuidad. Esta establece que, para cualquier volumen arbitrario y durante cualquier período de tiempo, la diferencia entre las entradas y salidas estará condicionada por la variación del volumen de agua almacenada (Sokolov A., 1981). Estos modelos hacen un balance de los volúmenes derramados, el déficit, los volúmenes evaporados, las...
Palavras-chave: Modelo; Humedales; Balance; Model; Wetland; Maestría; Hidrociencias.
Ano: 2011
URL: http://hdl.handle.net/10521/484

Expresión fisiológica y bioquímica del deterioro natural y artificial de semillas de Physalis ixocarpa Brot.
Provedor de dados: 32
Autores: Pichardo González, Juan Manuel.
México es centro de origen del tomate de cáscara (Physalis ixocarpa Brot.), el cual ocupa el cuarto lugar dentro de las especies olerícolas. La investigación en esta especie es escasa, particularmente en los procesos que ocasionan el deterioro de las semillas almacenadas, fenómeno que provoca una pérdida anual hasta de 10 % de germinación. La presente investigación se llevó a cabo en tres fases. En la primera se evaluaron respiración y contenido de ácidos grasos y su correlación con perdida de germinación y vigor en semillas deterioradas de P. ixocarpa var. CHF1-Chapingo, almacenadas hasta por siete años en una bodega sin control de clima. En la segunda fase, se evaluaron las mismas variables en semillas sometidas a envejecimiento acelerado (deterioro...
Palavras-chave: Tomate verde; Modelo; Acidos grasos; Respiración; Envejecimiento acelerado; Almacenamiento; Husk tomato; Model; Fatty acids; Respiration; Accelerated aging; Storage; Semillas; Doctorado.
Ano: 2010
URL: http://hdl.handle.net/10521/77

Expresión fisiológica y bioquímica del deterioro natural y artificial de semillas de Physalis ixocarpa Brot.
Provedor de dados: 32
Autores: Pichardo González, Juan Manuel.
México es centro de origen del tomate de cáscara (Physalis ixocarpa Brot.), el cual ocupa el cuarto lugar dentro de las especies olerícolas. La investigación en esta especie es escasa, particularmente en los procesos que ocasionan el deterioro de las semillas almacenadas, fenómeno que provoca una pérdida anual hasta de 10 % de germinación. La presente investigación se llevó a cabo en tres fases. En la primera se evaluaron respiración y contenido de ácidos grasos y su correlación con perdida de germinación y vigor en semillas deterioradas de P. ixocarpa var. CHF1-Chapingo, almacenadas hasta por siete años en una bodega sin control de clima. En la segunda fase, se evaluaron las mismas variables en semillas sometidas a envejecimiento acelerado (deterioro...
Palavras-chave: Tomate verde; Modelo; Acidos grasos; Respiración; Envejecimiento acelerado; Almacenamiento; Husk tomato; Model; Fatty acids; Respiration; Accelerated aging; Storage; Semillas; Doctorado.
Ano: 2010
URL: http://hdl.handle.net/10521/77

Simulación de la operación de la poza la becerra con fines de preservación de humedales, flora y fauna del Valle de Cuatro Ciénegas.
Provedor de dados: 32
Autores: Paredes Santaella, Andrés.
Se realizaron dos modelos, uno hidrológico y uno dinámico, para simular el comportamiento de la poza La Becerra, en el valle de Cuatro Ciénegas, Coahuila, para identificar el efecto de las extracciones de agua para el riego en la hidrología del humedal El Garabatal. Los modelos se basan en un balance hídrico, el cual está definido por la aplicación del principio de conservación de masas, también conocido como ecuación de la continuidad. Esta establece que, para cualquier volumen arbitrario y durante cualquier período de tiempo, la diferencia entre las entradas y salidas estará condicionada por la variación del volumen de agua almacenada (Sokolov A., 1981). Estos modelos hacen un balance de los volúmenes derramados, el déficit, los volúmenes evaporados, las...
Palavras-chave: Modelo; Humedales; Balance; Model; Wetland; Maestría; Hidrociencias.
Ano: 2011
URL: http://hdl.handle.net/10521/484

Coupled human and natural system dynamics as key to the sustainability of Lake Victoria&amp;#8217;s ecosystem services
Provedor de dados: 7
Autores: Downing, Andrea S.; Stockholm Resilience Centre, Stockholm University, Sweden; Aquatic Ecology and Water Quality Management group, Wageningen  University, Netherlands; Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands ; andrea.downing@su.se; van Nes, Egbert H.; Aquatic Ecology and Water Quality Management group, Wageningen  University, Netherlands ; Egbert.vannes@wur.nl; Balirwa, John S.; National Fisheries Resources Research Institute (NaFIRRI), Jinja, Uganda; jbalirwa@yahoo.com; Beuving, Joost; Department of Cultural Anthropology and Development Studies, Faculty of   Social Sciences, Radboud University, Nijmegen, Netherlands ; joostbeuving@gmail.com; Bwathondi, P.O.J.; University of Dar es Salaam, College of Natural and Applied Sciences,   Department of Aquatic Sciences and Fisheries, Dar es Salaam, Tanzania ; bwathondi@yahoo.co.uk; Chapman, Lauren J.; Department of Biology, McGill University, Montreal, Canada; lauren.chapman@mcgill.ca; Cornelissen, Ilse J. M.; Aquaculture &amp; Fisheries Group, Wageningen University, Netherlands; Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands; ilsecornelissen@hotmail.com; Cowx, Iain G.; Hull International Fisheries Institute, University of Hull, United Kingdom; I.G.Cowx@hull.ac.uk; Goudswaard, Kees P. C.; Institute for Marine Resource and Ecosystem Studies (IMARES), Wageningen University, Yerseke, Netherlands; kees.goudswaard@wur.nl; Hecky, Robert E.; Biology Department and Large Lakes Observatory, University of Minnesota-Duluth, USA; rehecky@gmail.com; Janse, Jan H.; Netherlands Environmental Assessment Agency (PBL), Bilthoven, Netherlands; Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands; JH.Janse@rivm.nl; Janssen, Annette B. G.; Aquatic Ecology and Water Quality Management group, Wageningen  University, Netherlands; Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands; A.Janssen@nioo.knaw.nl; Kaufman, Les; Boston University Marine Program, Biology Department, Boston University, USA ; lesk@bu.edu; Kishe-Machumu, Mary A.; Tanzania Fisheries Research Institute (TAFIRI), Dar es Salaam, Tanzania; mkishe@yahoo.com; Kolding, Jeppe; Department of Biology, University of Bergen, Norway; jeppe.kolding@bio.uib.no; Ligtvoet, Willem; Netherlands Environmental Assessment Agency (PBL), The Hague, Netherlands; Willem.Ligtvoet@pbl.nl; Mbabazi, Dismas; National Fisheries Resources Research Institute (NaFIRRI), Jinja, Uganda; mbabazidismas@yahoo.com; Medard, Modesta; Department of Sociology of Development and Change. Social Science Group, Wageningen University, Netherlands ; modesta.medard@wur.nl; Mkumbo, Oliva C.; Lake Victoria Fisheries Organisation, Jinja, Uganda; ocmkumbo@lvfo.org; Mlaponi, Enock; Tanzania Fisheries Research Institute (TAFIRI), Mwanza, Tanzania; emlaponi@yahoo.com; Munyaho, Antony T.; National Fisheries Resources Research Institute (NaFIRRI), Jinja, Uganda; ataabum@yahoo.com; Nagelkerke, Leopold A. J.; Aquaculture &amp; Fisheries Group, Wageningen University, Netherlands; leo.nagelkerke@wur.nl; Ogutu-Ohwayo, Richard; National Fisheries Resources Research Institute (NaFIRRI), Jinja, Uganda; ogutuohwayo@yahoo.com; Ojwang, William O.; Kenya Marine and Fisheries Research Institute (KMFRI), Kisumu, Kenya; w_ojwang@yahoo.com; Peter, Happy K.; Aquaculture &amp; Fisheries Group, Wageningen University, Netherlands; Happy.Peter@wur.nl; Schindler, Daniel E.; Aquatic &amp; Fishery Sciences/Department of Biology, University of Washington, USA; deschind@uw.edu; Seehausen, Ole; Eawag, Kastanienbaum, Switzerland; Ole.Seehausen@eawag.ch; Sharpe, Diana; Smithsonian Tropical Research Institute, Panama City, Panama; Department of Biology, McGill University, Montreal, Canada; diana.sharpe@gmail.com; Silsbe, Greg M.; Royal Netherlands Institute for Sea Research, Yerseke, Netherlands; Greg.Silsbe@nioz.nl; Sitoki, Lewis; The Technical University of Kenya, Nairobi, Kenya; Sitoki@hotmail.com; Tumwebaze, Rhoda; National Fisheries Resources Research Institute (NaFIRRI), Jinja, Uganda; t60rhoda@gmail.com; Tweddle, Denis; South African Institute for Aquatic Biodiversity, Grahamstown, South Africa; D.Tweddle@saiab.ac.za; van de Wolfshaar, Karen E.; Institute for Marine Resource and Ecosystem Studies (IMARES), Wageningen University, Ijmuiden, Netherlands; karen.vandewolfshaar@wur.nl; van Dijk, Han; Department of Sociology of Development and Change. Social Science Group, Wageningen University, Netherlands ; han.vandijk@wur.nl; van Donk, Ellen; Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands; E.vandonk@nioo.knaw.nl; van Rijssel, Jacco C.; Institute of Biology, University of Leiden, Netherlands; Naturalis Biodiversity Center, Leiden, Netherlands; Eawag, Kastanienbaum, Switzerland; j.c.van.rijssel@biology.leidenuniv.nl; van Zwieten, Paul A. M.; Aquaculture &amp; Fisheries Group, Wageningen University, Netherlands; paul.vanzwieten@wur.nl; Wanink, Jan; Institute of Biology, University of Leiden, Netherlands; Koeman en Bijkerk bv, Ecological Research and Consultancy, Haren, Netherlands; j.h.wanink@koemanenbijkerk.nl; Witte, F.; Institute of Biology, University of Leiden, Netherlands; Naturalis Biodiversity Center, Leiden, Netherlands;; Mooij, Wolf M.; Aquatic Ecology and Water Quality Management group, Wageningen  University, Netherlands; Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands ; w.mooij@nioo.knaw.nl.
East Africa&amp;#8217;s Lake Victoria provides resources and services to millions of people on the lake&amp;#8217;s shores and abroad. In particular, the lake&amp;#8217;s fisheries are an important source of protein, employment, and international economic connections for the whole region. Nonetheless, stock dynamics are poorly understood and currently unpredictable. Furthermore, fishery dynamics are intricately connected to other supporting services of the lake as well as to lakeshore societies and economies. Much research has been carried out piecemeal on different aspects of Lake Victoria&amp;#8217;s system; e.g., societies, biodiversity, fisheries, and eutrophication. However, to disentangle drivers and dynamics of change in this complex system, we need...
Tipo: Peer-Reviewed Reports
Palavras-chave: Eutrophication; Feedbacks; Fisheries; Lake Victoria; Model; Multidisciplinary  social-ecological system; Sustainability.
Ano: 2014

Response to: &amp;#8216;Should Ecosystem Management Involve Active Control of Species Abundances?&amp;#8217;
Provedor de dados: 7
Autores: Harron, Don E.; ; dharron@skyweb.ca.
Tipo: Peer-Reviewed Response
Palavras-chave: Model; Moose; Predation; Wolves; Woodland caribou.
Ano: 2006

Adaptive Capacity and Traps
Provedor de dados: 7
Autores: Carpenter, Stephen R; University of Wisconsin-Madison; srcarpen@wisc.edu; Brock, William A.; University of Wisconsin-Madison; WBrock@ssc.wisc.edu.
Adaptive capacity is the ability of a living system, such as a social&amp;#8211;ecological system, to adjust responses to changing internal demands and external drivers. Although adaptive capacity is a frequent topic of study in the resilience literature, there are few formal models. This paper introduces such a model and uses it to explore adaptive capacity by contrast with the opposite condition, or traps. In a social&amp;#8211;ecological rigidity trap, strong self-reinforcing controls prevent the flexibility needed for adaptation. In the model, too much control erodes adaptive capacity and thereby increases the risk of catastrophic breakdown. In a social&amp;#8211;ecological poverty trap, loose connections prevent the mobilization of ideas and resources...
Tipo: Peer-Reviewed Insight
Palavras-chave: Adaptation; Allostasis; Model; Poverty trap; Resilience; Rigidity trap; Transformation.
Ano: 2008

Landscape Change in the Southern Piedmont: Challenges, Solutions, and Uncertainty Across Scales
Provedor de dados: 7
Autores: Conroy, Michael J; USGS Cooperative Fish and Wildlife Research Unit; conroy@forestry.uga.edu; Allen, Craig; University of Nebraska; allencr@unl.edu; Peterson, James T; USGS Cooperative Fish and Wildlife Research Unit;; Pritchard, Lowell, Jr.; Emory University; lpritc2@emory.edu; Moore, Clinton T; ;.
The southern Piedmont of the southeastern United States epitomizes the complex and seemingly intractable problems and hard decisions that result from uncontrolled urban and suburban sprawl. Here we consider three recurrent themes in complicated problems involving complex systems: (1) scale dependencies and cross-scale, often nonlinear relationships;     (2) resilience, in particular the potential for complex systems to move to alternate stable states with decreased ecological and/or economic value; and (3) uncertainty in the ability to understand and predict outcomes, perhaps particularly those that occur as a result of human impacts. We consider these issues in the context of landscape-level decision making, using as an example water resources and lotic...
Tipo: Peer-Reviewed Reports
Palavras-chave: Piedmont; Adaptive management; Land use; Model; Resilience; Scale; Sprawl; Uncertainty; Urbanization; Water resources.
Ano: 2003

Plausible Stories or Tall Tales?
Provedor de dados: 7
Autores: Harron, Donald Earl; ; deharron@hotmail.com.
Tipo: Peer-Reviewed Response
Palavras-chave: Alberta; Linear corridors; Model; Seismic lines; Woodland caribou.
Ano: 2007

Searching Explanations of Nature in the Mirror World of Math
Provedor de dados: 7
Autores: Scheffer, Marten; Wageningen Agricultural University; Marten.Scheffer@wur.nl.
Despite the huge scientific progress of the last century, the dynamics of complex systems such as the atmosphere, human societies, and ecosystems remain difficult to understand and predict. Nonetheless, our ability to carve the future depends largely on our insight into the functioning of such complex systems. Complex systems are the focus of considerable mathematical theory. Rather than referring to any particular part of the world, such theory addresses what seems to be another world: a world of strange attractors, catastrophe folds, torus destruction, and homoclinic bifurcations. So disparate is the language and notation in this discipline that it is hard to imagine that it has any thing to do with reality as we know it. Indeed, it deals with a kind of...
Tipo: Peer-Reviewed Reports
Palavras-chave: Bifurcation; Catastrophe; Chaos; Cycle; Daphnia; Fish; Macrophyte; Model; Multiple stable states; Plankton; Predation; Trophic cascade.
Ano: 1999

A Theoretical Approach to Tourism Sustainability
Provedor de dados: 7
Autores: Casagrandi, Renato; Dipartimento di Elettronica e Informazione, Politecnico di Milano; casagran@elet.polimi.it; Rinaldi, Sergio; CIRITA, Politecnico di Milano; rinaldi@elet.polimi.it.
This paper shows that it is difficult, if not impossible, to formulate policies that guarantee that tourism can be maintained for a long time without severely impacting on the environment. The analysis is purely theoretical and is based on very simple and general assumptions about the interactions between the three main components of the system: the tourists, the environment, and the capital. These assumptions are encapsulated in a so-called minimal model, used to predict the economic and environmental impact of any given policy. This paper is of value for three reasons. First, it introduces the approach of minimal descriptive models in the context of tourism, which has traditionally been dominated by the use of black-box econometric models. Second, the...
Tipo: Peer-Reviewed Reports
Palavras-chave: Bifurcation analysis; Environment; Model; Nonlinear dynamics; Sustainability; Tourism.
Ano: 2002

Региональная модель для расчёта первичной продукции Чёрного моря с использованием данных спутникового сканера цвета SeaWiFS.
Provedor de dados: 13
Autores: Финенко, З. З.; Суслин, В. В.; Чурилова, Т. Я.
Разработана и применена малопараметрическая региональная модель для оценки первичной продукции Чёрного моря с использованием данных спутникового сканера цвета (SeaWiFS) за 1998 – 2004 гг. В модели использованы результаты исследований фотосинтетических характеристик черноморского фитопланктона и вертикального распределения хлорофилла, послужившие основой для обоснования и создания регионального алгоритма. Использованная  параметризация учитывает совместное действие плотности светового потока, температуры и концентрации хлорофилла  в поверхностном слое на фотосинтетические параметры кривой фотосинтез–свет и их изменение с глубиной. Полученные закономерности соединены с данными спутниковых измерений для оценки пространственно-временной вариабельности...
Tipo: Journal Contribution
Palavras-chave: Чёрное море; Модель; Спутник; Первичная продукция; Хлорофилл; Свет; Фитопланктон; Black Sea; Model; Satellite; Primary production; Chlorophyll; Light; Phytoplankton; Чорне море; Модель; Супутник; Первинна продукція; Хлорофіл; Світло; Фітопланктон.
Ano: 2009
URL: http://repository.ibss.org.ua/dspace/handle/99011/844

Regionalização espacial do nordeste do Estado do Pará.
Provedor de dados: 14
Autores: SANTOS, A. I. M. dos; HOMMA, A. K. O.
bitstream/item/40416/1/Boletim-Pesquisa-15-CPATU.pdf
Tipo: Séries anteriores (INFOTECA-E)
Palavras-chave: Regionalização; Modelo; Desenvolvimento; Nordeste; Pará; Amazônia Brasil; Regionalization; Model; Development.
Ano: 1980
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/378282

Análise de investimento de programas de melhoramento de pastagem para a produção de gado de corte no Cerrado.
Provedor de dados: 14
Autores: MONTEIRO, L. A.; CHUDLEIGH, P. D.; GARDNER, A. L.
Descrição do modelo. Suposições referentes ao sistema tradicional. Estrutura do modelo. Dados. Validação. Programa de computador. Experimentação. Resultados e discussão. Proporção de pastagem melhorada na fazenda e idade de venda de macho. Taxa de estabelecimento da pastagem cultivada. Método para aumentar o numero de vacas de cria. Método para aumentar o tamanho do rebanho. Compra de vacas velhas para engordar durante a estação chuvosa. Prioridade para o uso da pastagem melhorada.
Tipo: Documentos (INFOTECA-E)
Palavras-chave: Bovino de corte; Modelo; Aspecto econômico; Brasil; Sown pasture; Brazilian savannas; Production; Model; Simulation; Economic situation.; Cerrado; Pastagem Cultivada; Produção; Simulação.; Brazil; Beef cattle.
Ano: 1981
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/319643

Proposta para reformulação da estrutura de pesquisa do CPATU.
Provedor de dados: 14
Autores: EMBRAPA. Centro de Pesquisa Agropecuária do Trópico Úmido.
bitstream/item/198649/1/FL-04655.pdf
Tipo: Outras publicações técnicas (INFOTECA-E)
Palavras-chave: Agropecuária; CPATU; Modelo; Model; Instituição de Pesquisa; Agriculture; Research.
Ano: 1987
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/378833

Surface ocean CO2 in 1990–2011 modelled using a feed-forward neural network
Provedor de dados: 5
Autores: Zeng, Jiye; Nojiri, Yukihiro; Nakaoka, Shin-ichiro; Nakajima, Hideaki; Shirai, Tomoko.
This dataset includes the monthly distributions of CO2 fugacity in the world surface oceans reconstructed using a feed-forward neural network model and the CO2 measurements of the Surface Ocean CO2 Atlas version 2.0. It has a spatial resolution of 1 9 1° and spans a period of 22 years, from January 1990 to December 2011. The dataset also includes necessary parameters for the reconstruction and an estimate of the CO2 fluxes between the ocean and the atmosphere. The aim of this work is to provide a dataset for estimating the oceans’ contribution to the global carbon budget.
Tipo: Text
Palavras-chave: Ocean; CO2; Neural network; Model.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00293/40400/38957.pdf

Use of rotavirus virus-like particles as surrogates to evaluate virus persistence in shellfish
Provedor de dados: 5
Autores: Loisy, Fabienne; Atmar, R; Le Saux, Jean-claude; Cohen, J; Caprais, Marie-paule; Pommepuy, Monique; Le Guyader, Soizick.
Rotavirus virus-like particles (VLPs) and MS2 bacteriophages were bioaccumulated in bivalve mollusks to evaluate viral persistence in shellfish during depuration and relaying under natural conditions. Using this nonpathogenic surrogate virus, we were able to demonstrate that about 1 log(10) of VLPs was depurated after 1 week in warm seawater (22 degrees C). Phage MS2 was depurated more rapidly (about 2 log(10) in 1 week) than were VLPs, as determined using a single-compartment model and linear regression analysis. After being relayed in the estuary under the influence of the tides, VLPs were detected in oysters for up to 82 days following seeding with high levels of VLPs (concentration range between 10(10) and 10(9) particles per g of pancreatic tissue)...
Tipo: Text
Palavras-chave: Seawater; Viral diseases; Bioaccumulation; Depuration; Contamination; Model; Pancreas; Regression analysis; Shellfish; Phages; Virus.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-1233.pdf

Changements climatiques dans la mer de Barents : interactions glace-océan, formation et variabilité de la masse d'eau
Provedor de dados: 5
Autores: Barton, Benjamin I.
Winter sea ice has declined in the Barents Sea and there is growing evidence that the low sea ice here coincides with cold, winter surface air temperature in Europe and Asia. Atlantic Water (AW) transported into the Barents Sea is warming and its temperature variability is correlated with variability in sea ice extent. As AW extends into the Barents Sea it is modified into a cooler, fresher water mass called BarentsSea Water (BSW). There are limited observations of BSW despite its importance in the Arctic Ocean system, leading to the question, how does the seasonal sea ice impact ocean stratification and mean flow?First, satellite observations are used to find the Polar Front, a water mass boundary between BSW and fresher Arctic Water to the north. The sea...
Tipo: Text
Palavras-chave: Barents Sea Water; Front polaire; Banquise; Satellite; Modélisation; Model; Barents Sea Water; Polar front; Sea ice; Satellite.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00692/80424/83560.pdf

Mosaic community dynamics on Juan de Fuca Ridge sulphide edifices: substratum, temperature and implications for trophic structure
Provedor de dados: 5
Autores: Sarrazin, Jozee; Levesque, Christian; Juniper, S; Tivey, Margaret.
Introduction : Ecological studies at hydrothermal vents often emphasize the importance of spatio-temporal heterogeneity in organism distribution within individual sites (Sarrazin et al., 1997) but the relative roles of environmental conditions, biological interactions and/or random processes in structuring hydrothermal communities remain poorly understood (Sarrazin &amp; Juniper, 1999). A model of community succession developed by Sarrazin et al. (1997, 1999) proposed that a series of faunal assemblages form a mosaic community that colonizes hydrothermal edifices of the northeast Pacific vents. This paper further develops the succession model by incorporating new observations. At the core of the model is the recognition of distinct faunal assemblages that...
Tipo: Text
Palavras-chave: Model; Environmental conditions; North east Pacific; North east Pacific; Hydrothermal vent.
Ano: 2002
URL: https://archimer.ifremer.fr/doc/2002/publication-893.pdf

Understanding patterns and processes in models of trophic cascades
Provedor de dados: 5
Autores: Heath, Michael R.; Speirs, Douglas C.; Steele, John H.
Climate fluctuations and human exploitation are causing global changes in nutrient enrichment of terrestrial and aquatic ecosystems and declining abundances of apex predators. The resulting trophic cascades have had profound effects on food webs, leading to significant economic and societal consequences. However, the strength of cascades-that is the extent to which a disturbance is diminished as it propagates through a food web-varies widely between ecosystems, and there is no formal theory as to why this should be so. Some food chain models reproduce cascade effects seen in nature, but to what extent is this dependent on their formulation? We show that inclusion of processes represented mathematically as density-dependent regulation of either consumer...
Tipo: Text
Palavras-chave: Bottom-up; Density dependence; Food chain; Food web; Harvesting; Model; Predator-prey; Simulation; Top-down.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00171/28249/26505.pdf

Surface circulation in the Eastern Mediterranean using drifters (2005-2007)
Provedor de dados: 5
Autores: Gerin, R.; Poulain, P. -m.; Taupier-letage, Isabelle; Millot, C.; Ben Ismail, S.; Sammari, Cherif.
Within the framework of the EGITTO/EGYPT programs, the spatial structure and the temporal variability of the surface circulation in the eastern basin of the Mediterranean Sea was studied with satellite-tracked drifters. A total of 97 drifters drogued to 15-m nominal depth were released between September 2005 and March 2007, regularly along ship-of-opportunity routes in the Sicily Channel and within specific structures during dedicated campaigns in the Levantine sub-basin. This study complements previous ones in the former and in the Ionian, but it is the first one in the latter. After editing and low-pass filtering, the drifter trajectories were used to estimate pseudo-Eulerian statistics: mean current, variance ellipses, mean and eddy kinetic energies. A...
Tipo: Text
Palavras-chave: Lagrangian drifters; General circulation; Undrogued drifters; Sea; Variability; Features; Basin; Model; Dynamics.
Ano: 2009
URL: https://archimer.ifremer.fr/doc/00204/31480/29891.pdf

Challenges and Prospects in Ocean Circulation Models
Provedor de dados: 5
Autores: Fox-kemper, Baylor; Adcroft, Alistair; Boening, Claus W.; Chassignet, Eric P.; Curchitser, Enrique; Danabasoglu, Gokhan; Eden, Carsten; England, Matthew H.; Gerdes, Ruediger; Greatbatch, Richard J.; Griffies, Stephen M.; Hallberg, Robert W.; Hanert, Emmanuel; Heimbach, Patrick; Hewitt, Helene T.; Hill, Christopher N.; Komuro, Yoshiki; Legg, Sonya; Le Sommer, Julien; Masina, Simona; Marsland, Simon J.; Penny, Stephen G.; Qiao, Fangli; Ringler, Todd D.; Treguier, Anne-marie; Tsujino, Hiroyuki; Uotila, Petteri; Yeager, Stephen G.
We revisit the challenges and prospects for ocean circulation models following Griffies et al. (2010). Over the past decade, ocean circulation models evolved through improved understanding, numerics, spatial discretization, grid configurations, parameterizations, data assimilation, environmental monitoring, and process-level observations and modeling. Important large scale applications over the last decade are simulations of the Southern Ocean, the Meridional Overturning Circulation and its variability, and regional sea level change. Submesoscale variability is now routinely resolved in process models and permitted in a few global models, and submesoscale effects are parameterized in most global models. The scales where nonhydrostatic effects become...
Tipo: Text
Palavras-chave: Ocean circulation; Model; Parameterization; Climate; Ocean processes.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00488/59989/63213.pdf

Impact of temperature inversions on SST evolution in the South-Eastern Arabian Sea during the pre-summer monsoon season
Provedor de dados: 5
Autores: Durand, F; Shetye, Sr; Vialard, Jerome; Shankar, D; Shenoi, Ssc; Ethe, C; Madec, G.
Temperature inversions are known to occur in the near-surface ocean regime where salinity stratification is large enough to influence the density field. However, they have not been known as features that alter near-surface processes significantly to influence the sea surface temperature (SST). From the analysis of new observed datasets as well as of state-of-the-art numerical model outputs, this paper shows that heat trapped within a temperature inversion makes significant contribution to warming of the SST in the South-Eastern Arabian Sea during the pre-southwest monsoon season.
Tipo: Text
Palavras-chave: Mixed layer; Toga decade; Ocean; Variability; Salinity; Physics; Model; Onset; OGCM; Pool.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00203/31424/29815.pdf

Computed residual flow through the Dover Strait
Provedor de dados: 5
Autores: Salomon, Jean-claude; Breton, Marguerite; Guegueniat, Pierre.
A two-dimensional numerical model was used for the empirical deduction of a mathematical expression of water flow through the Dover Strait, for all conditions of tide, wind and ocean slope.  The theoretical results were correlated with sea measurements of radioactive tracers discharged at La Hague cape.  Nine actual years (1983-1991) were then examined, determining an average annual flow of 114000 mas-1 with a very high monthly variability, but with little difference from one year to the next.  These residual currents being highly sensitive to weather conditions, the mildness of the past few years has occasioned a decrease in fluxes towards the North Sea
Tipo: Text
Palavras-chave: Manche; Pas de Calais; Débit; Modèle; Marée; Channel; Dover Strait; Flow; Model; Tide.
Ano: 1993
URL: http://archimer.ifremer.fr/doc/1993/publication-542.pdf

Modélisation de la bioaccumulation de métaux traces (Hg, Cd, Pb, Cu et Zn) chez la moule, Mytilus galloprovincialis, en milieu méditerranéen
Provedor de dados: 5
Autores: Casas, Stellio.
Monitoring coastal contamination of trace metals using bivalve molluscs as quantitative bioindicators is widely used in many international monitoring programs. The bioaccumulation of metal within an organism results from the interaction between physiological (growth, loss of weight, absorption, accumulation), chemical (metal concentration, speciation, bioavailability) and environmental factors (temperature, SPM, chlorophyll). By utilizing the parameters above in this study, it appears that modeling metal dynamics in marine mussels is a reliable tool. The model allows understanding the bioaccumulation process which results from the interactions between biological, chemical and environmental factors. One of the objective of this study was to couple a...
Tipo: Text
Palavras-chave: Biomonitoring; Dynamic Energy Budget; Model; Trace metals; Bioaccumulation; Mytilus galloprovincialis; Mussel; Bioindicator; Surveillance; Budget énergétique dynamique; Modèle; Métaux traces; Bioaccumulation; Mytilus galloprovincialis; Moule; Bioindicateur.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/these-356.pdf

A non-linear viscoelastic viscoplastic model for the behaviour of polyester fibres
Provedor de dados: 5
Autores: Chailleux, Emmanuel; Davies, Peter.
In this study the macroscopic analysis proposed by Schapery has been applied to model the non-linear viscoelastic and viscoplastic behaviour of polyester fibres. First, a special non-contact extensometry method has been developed in order to measure the fibre response without affecting the behaviour of these extremely anisotropic fibres. An accelerated identification method has then been developed. This enables a unique and independent set of parameters to be determined, which separate the reversible and non-reversible mechanisms responsible for measured strains. The model prediction for an arbitrary loading sequence corresponds closely to the measured strains. The model has been applied here at the yarn level but can equally well be used to predict rope...
Tipo: Text
Palavras-chave: Viscoplastic; Viscoelastic; Polyester; Non linear; Model; Fibre.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-794.pdf

Study of the manoeuvrability and security of a trawl gear
Provedor de dados: 5
Autores: Marichal, Dominique; Vincent, Benoit.
A complete method is presented for determining the static and dynamic behaviour of a fishing gear. The net, which is very flexible, is modelised by a set of rigid bars. The hydrodynamic forces, applied to each bar, are determined by combining and generalizing the Landweber and Morison hypothesis. A CFD method is used to calculate the forces on trawl doors. The fundamental principle of dynamics is completed with length equations expressing the elasticity of the bars. It leads to a set of second order non-linear differential equations, which is solved using a Runge-Kutta method. We will now present a few examples of the various applications of our works : the study of the trawl gear equilibrium in a uniform flow, an example of manoeuvrability (gyration of...
Tipo: Text
Palavras-chave: Runge Kutta; Elasticity; Simulation; Model; Trawl doors; Hydrodynamic; Fishing gear; Runge Kutta; Elasticite; Simulation; Modèle; Panneaux de chalut; Hydrodynamique; Engin de pêche.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/acte-4612.pdf

Modeled mixed-layer salinity balance in the Gulf of Guinea: seasonal and interannual variability
Provedor de dados: 5
Autores: Da-allada, Casimir Yelognisse; Du Penhoat, Yves; Jouanno, Julien; Alory, Gael; Hounkonnou, Norbert Mahouton.
A regional numerical simulation and observations were used to investigate the various processes controlling mixed-layer salinity balance on seasonal and interannual time scales in the Gulf of Guinea. Processes were quantified using a mixed-layer salt budget. Model results correctly reproduced the mean, phase, and amplitude of observed seasonal near-surface salinity. The results indicated that on seasonal time scales, the mixed-layer salinity balance differed from one region to another. The surface salinity seasonal cycle was characterized by strong salinization during May for coastal areas north and south of the equator. Model results suggested that vertical mixing controls the mixed-layer salinity increase at the equator during May, while both vertical...
Tipo: Text
Palavras-chave: Sea surface salinity; Gulf of guinea; Model; Mixed-layer budget; Seasonal variability; Interannual variability.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00242/35333/36310.pdf

Characteristics of the convergence zone at the eastern edge of the Pacific warm pool
Provedor de dados: 5
Autores: Maes, Christophe; Picaut, Joël; Kuroda, Yoshifumi; Ando, Kentaro.
The characteristics of the convergence zone at the eastern edge of the equatorial Pacific warm pool are studied using a compilation of in-situ current and salinity measurements during the period 1992-2001. The displacement of the convergence zone is observed, for the first time, as far west as 140degreesE in the far western Pacific, mainly during La Nina periods, and near 140degreesW in the central Pacific during the 1997-98 El Nino. The convergence zone may be associated with a salinity front dividing the fresh waters of the warm pool from the salty waters upwelled in the central equatorial Pacific. Despite a zonal displacement ranging over about one fifth of the equatorial circumference of the earth, the characteristics of the main parameters involved in...
Tipo: Text
Palavras-chave: Nino la nina; El nino; Salinity variability; Southern oscillation; Fresh pool; Sea level; Displacements; Temperature; Model; Ocean.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00208/31888/30307.pdf

A model of sediment transport under the influence of surface bioturbation: generalisation to the facultative suspension-feeder Scrobicularia plana
Provedor de dados: 5
Autores: Orvain, Francis.
Flume experiments were designed to study how sediment erodibility was modified by the facultative suspension-feeder Scrobicularia plana living at different densities in sediment beds of various degrees of compaction. Two separate erosion phases were identified from the resuspension kinetics: (1) erosion of an unconsolidated surficial layer (i.e. fluff layer) and (2) the subsequent bed erosion. S. plana were found to influence both erosion phases: (1) erosion rates of the fluff layer were controlled by bioturbation activities, the extents of which were influenced by bivalve density and the degree of compaction of the sediments, and (2) critical thresholds of the subsequent bed erosion decreased as clam density increased, likely due to depressions in the...
Tipo: Text
Palavras-chave: Resuspension; Model; Functional groups; Sediment transport; Bioturbation; Scrobicularia plana; Intertidal mudflat.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-3776.pdf

Étude du comportement non-linéaire d'une colle dans un assemblage
Provedor de dados: 5
Autores: Cognard, Jean-yves; Sohier, Laurent; Davies, Peter; Gineste, Bernard.
The objective of this study is to define a reliable tool for dimensioning of adhesively bonded assemblies, particularly for marine and underwater applications. A modified “Arcan” fixture, suited for the study of the behavior of bonded metal-metal assemblies, was developed in order to focus on the analysis of the behavior of the adhesive in thin films. To analyze the kinematics of the deformation of the adhesive joint non-contact extensometry techniques were employed. Thus various characteristics of the non-linear behavior of the adhesive were observed. The first results obtained for mixed assemblies (steel, aluminium, composite substrates) show similar behaviour of the adhesive using the proposed procedure. Furthermore, quality controls by DSC, and studies...
Tipo: Text
Palavras-chave: Ssemblages collés; Modélisation; Essais; Comportement non-linéaire; Composites; Adhesive bonding; Model; Tests; Non linear behaviour; Composite.
Ano: 2006
URL: https://archimer.ifremer.fr/doc/00480/59156/61785.pdf

Mesures sur chaluts jumeaux au bassin d'essai de pêche de Lorient
Provedor de dados: 5
Autores: Meillat, Marc.
These basin tests follow up the campaign done on board the n/o GWEN-DREZ from 12 November to 6 December 1985 with the goal of observing the respective behaviours of the twin trawls and the single trawl of the same type. The mock-ups created for the basin are derived from 23.90 metre shrimp trawls assembled by LE DREZEN Company following an IFREMER plan for COTONEC Company in Guyana.
Tipo: Text
Palavras-chave: Model; Flume tank; Twin trawls; Fising technology; Maquette; Technologie des pêches; Bassin d'essai; Chaluts jumeaux.
Ano: 1986
URL: http://archimer.ifremer.fr/doc/1986/rapport-2668.pdf

Un modèle général de d'évolution de l'océan indien
Provedor de dados: 5
Autores: Sahabi, Mohamed.
The last global synthesis of the evolution of the Indian ocean which satisfactorily describes the kinematics of the five major plates, up to the initial stages, dates back to Norton and Sclater [1979]. Although the most recent phases of evolution have been largely detailed, in particular in the proximity of the triple junction, the initial stages of evolution have been generally described by models quite speculative and generally only constrained by pairs of plates.  The recentmost gravity data based on the altimetric satellites SEASAT, GEOSAT and ERS1 [Sandwell and Smith, 1992] give an homogenoeus image of sea-floor topography. These data, declassified to the south of 30°S, reveal previously unknowkn features of the sea-floor fabric and allow to further...
Tipo: Text
Palavras-chave: Indian ocean; Model; Map; Fracture zone; Intraplate deformation; Kinematics; Ocean Indien; Modellisation; Carte; Zone fracture; Faille transformante; Cinématique.
Ano: 1993
URL: http://archimer.ifremer.fr/doc/1993/these-614.pdf

Importance of the Equatorial Undercurrent on the Sea Surface Salinity in the Eastern Equatorial Atlantic in boreal spring
Provedor de dados: 5
Autores: Da-allada, Casimir Yelognisse; Jouanno, J.; Gaillard, Fabienne; Kolodziejczyk, Nicolas; Maes, C.; Reul, Nicolas; Bourles, B.
The physical processes implied in the sea surface salinity (SSS) increase in the equatorial Atlantic Cold Tongue (ACT) region during boreal spring and the lag observed between boreal spring SSS maximum and sea surface temperature (SST) summer minimum are examined using mixed-layer salinity budgets computed from observations and model during the period 2010-2012. The boreal spring SSS maximum is mainly explained by an upward flux of high salinity originating from the core of the Equatorial Undercurrent (EUC) through vertical mixing and advection. The vertical mixing contribution to the mixed-layer salt budget peaks in April-May. It is controlled primarily by i) an increased zonal shear between the surface South Equatorial Current and the subsurface EUC and...
Tipo: Text
Palavras-chave: Atlantic Cold Tongue; SMOS SSS; Model; EUC salinity maximum; Vertical processes.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00363/47396/47388.pdf

Natural variability of bio-optical properties in Case 1 waters: attenuation and reflectance within the visible and near-UV spectral domains, as observed in South Pacific and Mediterranean waters
Provedor de dados: 5
Autores: Morel, A.; Claustre, H.; Antoine, D.; Gentili, B.
The optical properties of Case 1 waters have been empirically related to the chlorophyll concentration, [Chl], historically used as an index of the trophic state and of the abundance of the biological materials. The well-known natural variability around the mean statistical relationships is here examined by comparing the apparent optical properties (spectral downward irradiance attenuation and reflectance) as a function of [Chl] in two Case 1 environments, the Pacific and Mediterranean waters. These oceanic zones apparently represent two extremes of the possible bio-optical variability range around the mean. The systematic deviations, in both directions with respect to the average laws, mainly result from the differing contents in non-algal detrital...
Tipo: Text
Palavras-chave: Light absorption; Algal biomass; Ocean color; Chlorophyll; Sea; Phytoplankton; Model; Coefficients; Algorithms.
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00209/32012/30549.pdf

Effects of Ignoring Survey Design Information for Data Reuse
Provedor de dados: 5
Autores: Foster, Scott D.; Vanhatalo, Jarno; Trenkel, Verena; Schulz, Torsti; Lawrence, Emma; Przeslawski, Rachel; Hosack, Geoffrey R.
Data are currently being used, and reused, in ecological research at an unprecedented rate. To ensure appropriate reuse however, we need to ask the question: “Are aggregated databases currently providing the right information to enable effective and unbiased reuse?” We investigate this question, with a focus on designs that purposefully favour the selection of sampling locations (upweighting the probability of selection of some locations). These designs are common and examples are those designs that have uneven inclusion probabilities or are stratified. We perform a simulation experiment by creating datasets with progressively more uneven inclusion probabilities, and examine the resulting estimates of the average number of individuals per unit area...
Tipo: Text
Palavras-chave: Bias; Survey Design; Database; Population Density Estimate; Model; Horvitz‐Thompson; FAIR; Reuse; Data; Inclusion Probability.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00691/80339/83422.pdf

Contribution of the Amazon River Discharge to Regional Sea Level in the Tropical Atlantic Ocean
Provedor de dados: 5
Autores: Giffard, Pierrick; Llovel, William; Jouanno, Julien; Morvan, Guillaume; Decharme, Bertrand.
Tipo: Text
Palavras-chave: Sea level; Amazon River; River plume; Salinity; Model; NEMO; Tropical Atlantic.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00591/70268/68327.pdf

Rejets urbains. Volet Manche - Atlantique - Site de Morlaix - Etudes sédimentologique et Bathymétrique de l' estuaire de Morlaix
Provedor de dados: 5
Autores: Bassoullet, Philippe; L'Yavanc, Jacky; Guillaud, Jean-francois; Loarer, Ronan; Breton, Marguerite.
In order to increase our knowledge about sediment transport in the bay and maritime part of the River of Morlaix (Finistère), measurernènts have been perforrned on site. This report gives the granulometrical and physical parameters of the sediments as weIl as the hydrodynamics, used for a model of particulate transport in the area. The rnodel and its application will be published later
Tipo: Text
Palavras-chave: Rejet urbain; Sédiment; Granulométrie; Hydrodynamique; Modèle de transport particulaire; Sable; Vase; Estuaire de Morlaix.; Urban wastes; Model; Sediment; Granulometry; Hydrodynamics; Sand; Mud; Sedimentary transport model; Morlaix estuary.
Ano: 1987
URL: http://archimer.ifremer.fr/doc/00345/45658/45293.pdf

Vers une modélisation déterministe des écoulements de surface en Nouvelle-Calédonie. Implémentation du code GR4H sur quatre bassins versants du Grand Nouméa
Provedor de dados: 5
Autores: Desclaux, Terence; Pischedda, Marine; Lemonnier, Hugues; Soulard, Benoit; Le Gendre, Romain.
Ce rapport fait suite au stage de Marine Pischedda (Master 2 La Rochelle) réalisé au sein de l’unité de recherche "Lagons, Ecosystèmes et Aquaculture Durable en Nouvelle-Calédonie" (LEAD/NC) de l’Ifremer entre février et juillet 2016. Cette étude a été conduite sur quatre bassins versants du Grand Nouméa : la Coulée, la Dumbéa Est, la Dumbéa Nord et la Couvelée. L’objectif principal était de démontrer la pertinence de l’utilisation de modèle pluie-débit au pas de temps horaire (GR4H en l’occurrence) sur les bassins versants calédoniens. Le cadre plus général de ce travail était d’aboutir à une représentation affinée du continuum terre-mer par le couplage des modèles GR4H et MARS3D développés pour simuler la circulation côtière. Les périodes d’étiages ayant...
Tipo: Text
Palavras-chave: Continuum Terre-Lagon; Nouvelle-Calédonie; Rivières; GR4H; Bassins versants; Grand Nouméa; Modélisation; Débits; Land-lagoon continuum; New Caledonia; River; GR4H; Watershed; Nouméa; Model; River Flow.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00388/49969/50545.pdf

Interactions vagues-banquise en zones polaires
Provedor de dados: 5
Autores: Boutin, Guillaume.
Sea ice, which covers most of the ocean near the poles, is a key component of the climate system. Global warming is driving its massive melting, especially in the Arctic. Where sea ice cover decreases, fetch increases leading to more energetic sea states. This means potentially enhanced wavesice interactions effects in the future. The quick evolution of sea ice extent and volume combined with the intensification of human activities in polar regions urge us to improve our understanding of waves-ice interactions.Sea ice attenuates waves. They can however propagate through it and break it far into the ice cover. Attenuation depends on ice properties such as floe size, thickness, etc. Once broken, resulting floes are more likely to drift and melt. In addition,...
Tipo: Text
Palavras-chave: Vagues; Banquise; Modélisation; Zone Marginale de Glace; Waves; Sea ice; Model; Marginal Ice Zone.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00498/60968/64376.pdf

Les risques conchylicoles en Baie de Quiberon. Troisième partie : le risque d’hypoxie pour l’huître creuse Crassostrea gigas. Rapport final du projet Risco 2010-2013
Provedor de dados: 5
Autores: Stanisiere, Jean-yves; Mazurie, Joseph; Bouget, Jean-francois; Langlade, Aime; Gabellec, Raoul; Retho, Michael; Quinsat, Kevin; Leclerc, Emilie; Cugier, Philippe; Dussauze, Morgan; Menesguen, Alain; Dumas, Franck; Gohin, Francis; Augustin, Jean-marie; Ehrhold, Axel; Sinquin, Jean-marc; Goubert, Evelyne; Dreano, Alain.
The project “Risco”, supported by the “Pôle Mer” and funded by the Regional Council of Brittany, deals with specific risks of mortality of oysters, Crassostrea gigas, cultivated on the bottom, in a subtidal bay of South Brittany : the bay of Quiberon (56, France). Massive mortalities of oysters were reported in summer 2006 in this bay, exclusively located in the deep muddy area with a positive gradient eastward. A validated biogeochemical model was applied in order to simulate the dissolved oxygen over 2000-2006 : it revealed several episodes of hypoxia, more or less intense according to years, but with the same spatial distribution. This approach proved 2006 to be the most hypoxic year since 2000. The hypoxia was due to a rare conjunction of 3 factors :...
Tipo: Text
Palavras-chave: Baie Quiberon; Crassostrea gigas; Huître; Mortalité; Croissance; Hypoxie; Oxygène; Modèle; Upwelling; Loire; Vilaine; Quiberon; Crassostrea gigas; Oyster; Mortality; Growth; Hypoxia; Oxygen; Model; DEB; Upwelling; Loire; Vilaine.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00180/29131/27535.pdf

Mussel (Mytilus edulis) culture management along the Normandy coastline (France) : stock assessment and growth monitoring
Provedor de dados: 5
Autores: Goulletquer, Philippe; Joly, Jean-pierre; Le Gagneur, Eric; Ruelle, Francois.
The Normandy region is presently a leading shellfish rearing area in France yielding 35,000 metric tons of oysters C. gigas and Il,000 metric tons of mussels M. edulis on a yearly basis. Preliminary studies were initiated in 1989, 1991 and 1992 to develop the sampling strategy for cultured mussel stock assessment. Comprehensive mussel stock assessment and concomitant growth monitoring were carried out in 1993 to study mussel population and optimize overall s1l1ellfish culture management.  A three-stage cluster sampling strategy combined with stratification was tested on the 278 kms 'bouchot' type culture with a sampling effort of 275 units. Stratification was based upon two criteria including geographical sector and tidal level. Overall biomass was...
Tipo: Text
Palavras-chave: Model; Growth monitoring; Stock assessment; Mytilus edulis; Blue mussel; Modèle; Suivi de croissance; Estimation de stocks; Mytilus edulis L.; Moule bleue.
Ano: 1994
URL: http://archimer.ifremer.fr/doc/1994/acte-3073.pdf

High-resolution barotropic modeling and the calving of the Mertz Glacier, East Antarctica
Provedor de dados: 5
Autores: Mayet, C.; Testut, L.; Legresy, B.; Lescarmontier, L.; Lyard, F.
In February 2010, the Mertz Glacier Tongue (MGT) calved, releasing an 80 x 40 km iceberg. We have developed a high-resolution barotropic ocean model of the region to simulate the local circulation in response to tides and atmospheric forcing. We improved the coastline, grounding line position and built a new bathymetry using satellite imagery and older bathymetry data to derive the best available tidal model for the region. We compared this and other available models to seven different sea level observations available in the area and significantly improved the tidal solutions reaching a root sum square of 2.3 cm. This model was then run in different bathymetric configurations, considering the ice draft of the major icebergs B9B and C28, to simulate the...
Tipo: Text
Palavras-chave: Mertz Glacier; Icebergs; Calving; Barotropic; Model.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00244/35568/34097.pdf

Modèle tridimensionnel de circulation et de dispersion en zone côtière à marée. Premiers essais : cas schématique et baie de Seine
Provedor de dados: 5
Autores: Thouvenin, Benedicte; Salomon, Jean-claude.
In order to reproduce and investigate the marine circulation in the coastal tidal zone, and especially its three dimensional nature, it appeared interesting to develop a numerical mode! which could take account of the real bottom topography and the variations of the free surface. Navier-Stokes equations are solved in a straight forward manner, generalizing a finite difference technique already used in two-dimensional vertical models. To test the computational program, the mode! was applied to a number of flat bottom schematic basins, where we reproduced wind driven currents and tide propagation. Then we considered the particular case of a real channel and, finally, density currents associated with a salty wall. Mode) results are compared to theoretical...
Tipo: Text
Palavras-chave: Modèle; Courant; Tridimensionnel; Seine; Côtier; Model; Current; Three-dimensional; Seine; Coastal.
Ano: 1984
URL: http://archimer.ifremer.fr/doc/00113/22440/20127.pdf

Analysis of tagging data from North Atlantic Albacore (Thunnus Alalunga): Attrition Rate Estimates
Provedor de dados: 5
Autores: Ortiz De Zarate, Victoria; Bertignac, Michel.
In this study, an attempt is made to estimate natural mortality rate for North Atlantic albacore. We implement a spatially aggregated tag-attrition model to analyse the results of an albacore tagging experiment conducted in the Bay of Biscay from 1988 to 1991. The model predicts probabilities of the possible fates of tagged fish and the tags that they carry. The model includes several parameters consisting of catchabilities by fleets involved in recaptures and a combination of natural mortality plus emigration from the study area. Model fitting is carried out by finding the maximum of a multinomial likelihood function. Effect of reporting rate values on the estimations are evaluated and several hypothesis on the pre-mixing period of the tagged fish...
Tipo: Text
Palavras-chave: Bay of Biscay; Attrition rate; Model; Natural mortality estimation; Albacore.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/2001/publication-977.pdf

Intraseasonal variability of equatorial Indian Ocean zonal currents
Provedor de dados: 5
Autores: Sengupta, Debasis; Senan, Retish; Goswami, B. N.; Vialard, Jerome.
New satellite and in situ observations show large intraseasonal (10-60 day) variability of surface winds and upper- ocean current in the equatorial Indian Ocean, particularly in the east. An ocean model forced by the Quick Scatterometer (QuikSCAT) wind stress is used to study the dynamics of the intraseasonal zonal current. The model has realistic upper- ocean currents and thermocline depth variabilities on intraseasonal to interannual scales. The quality of the simulation is directly attributed to the accuracy of the wind forcing. At the equator, moderate westerly winds are punctuated by strong 10-40-day westerly wind bursts. The wind bursts force swift, intraseasonal (20-50 day) eastward equatorial jets in spring, summer, and fall. The zonal momentum...
Tipo: Text
Palavras-chave: Sea surface temperature; Interannual variability; Dynamics; Circulation; Pacific; Model; Winds; Thermodynamics; Oscillation; Transports.
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00203/31421/29820.pdf

The influence of sediment cohesiveness on bioturbation effects due to Hydrobia ulvae on the initial erosion of intertidal sediments: A study combining flume and model approaches
Provedor de dados: 5
Autores: Orvain, F; Sauriau, Pierre-guy; Bacher, Cedric; Prineau, Michel.
Laboratory experiments performed in a recirculating flume were designed to quantify the bioturbation influence of the mud snail Hydrobia ulvae, one of the most abundant deposit feeders on European intertidal mudflats. Variations in sediment moisture content that occur between bedforms in shore-normal, ridge and runnel systems of intertidal mudflats were added to the model definition. Sediment erosion thresholds, erosion rates and the microalgal pigment composition of resuspended material were quantified for different H. ulvae densities (0, 1000, 5000, 10 000 and 50 000 snails m(-2)) and applied bed shear stresses. Two different sediment moisture contents were tested. In the absence of macrofauna, recorded turbidities increased up to the maximum applied...
Tipo: Text
Palavras-chave: Model; Flume; Chloropigments; Ridges and tunnels; Mudflat; Sediment; Hydrobia ulvae; Bioturbation; Resuspension.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-3774.pdf

Using a quantitative model for participatory geo-foresight: ISIS-Fish and fishing governance in the Bay of Biscay
Provedor de dados: 5
Autores: Provot, Zoe; Mahévas, Stephanie; Tissière, Laurie; Michel, C.; Lehuta, Sigrid; Trouillet, B.
This study investigated the use of a complex quantitative simulation model for participatory geo-foresight for the governance of the marine socio-ecosystem in the Bay of Biscay. The approach is simulation-based combining qualitative and quantitative expert-knowledge focusing on the demersal fishery in the Bay of Biscay. A three-stage approach was carried out : (i) translation by stakeholders of a narrative scenario drawn up during the geo-foresight into quantitative sub-scenarios that could be parameterized in ISIS-Fish; (ii) simulation with ISIS-Fish and study of the consequences of the sub-scenarios on the dynamics of the fishery; and (iii) participants feedback on the relevance of the model, on the possibility to detail the narrative scenario further...
Tipo: Text
Palavras-chave: Geo-foresight; Participatory; Spatial; Complex quantitative; Model; ISIS-Fish; Scenarios; Fishery dynamics; Bay of Biscay.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00459/57034/69604.pdf

The Alderney Race: General hydrodynamic and particular features
Provedor de dados: 5
Autores: Bailly Du Bois, P; Dumas, Franck; Morillon, M; Furgerot, L; Voiseux, C; Poizot, E; Mear, Y; Bennis, Anne-claire.
This study presents an overview of the main hydrodynamic features of the Alderney Race strait based on in-situ measurements and 2D hydrodynamic model simulations. The strait encompasses a large amplitude of tidal properties (tidal range and tidal wave propagation) and particularly strong currents exceeding 5 m.s-1 with associated counter currents and gyres. Variations in depth, sea bottom roughness, coastal topography and current orientation around the La Hague Cape provide access to a large variety of original hydrodynamic regimes. Some are revealed as locations with a 0.4 m drop in the mean sea level associated with strong average currents. A resonance effect associated with the offshore currents can also be observed close to the coasts. The "St Martin...
Tipo: Text
Palavras-chave: Alderney Race; La Hague Cape; Current; Tide; Hydrodynamics; Model.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00641/75286/75639.pdf

A model for predicting the quantities of dissolved inorganic nitrogen released in effluents from a sea bass (Dicentrarchus labrax) recirculating water system
Provedor de dados: 5
Autores: Pagand, Pascal; Blancheton, Jean-paul; Casellas, Claude.
Fish excretions and the transformation of nitrogen by bacteria in the nitrifying biofilter are two of the main sources of dissolved inorganic nitrogen (DIN) in fish farms that use recirculating water systems. In this study, the DIN concentration in an experimental Dicentrarchus labrax aquaculture system was calculated using empirical sub-models for fish growth, ingested food and water replacement. The specific growth rate (SGR) (% day(-1)) and the daily feeding rate (DFR) (% day(-1)) both depend on the average weight, W (g), of the fish: Y = aW(b), where Y may be SGR or DFR, and a and b are empirical constants. The DIN discharge rate, Gamma(N) (% of ingested nitrogen), in the experimental aquaculture system was expressed as a function of increasing...
Tipo: Text
Palavras-chave: Recirculating water system; Nitrogen production; Model; Fish farm effluent; European sea bass; Dissolved inorganic nitrogen.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/2000/publication-514.pdf

Towed Gear Optimisation, application to trawls
Provedor de dados: 5
Autores: Roullot, Jean; Vincent, Benoit.
IFREMER has been developing and commercialising scientific software to help the conception and optimisation of any kind of trawl. This software named DynamiT makes available a "virtual flume tank" where tests can be achieved without any constraint due to scale effects or other limitation when physically testing out. DynamiT has been used numbers of times to simulate and optimise trawls by different net makers and by IFREMER. The software is based on the resolution of the mechanics (structure and hydrodynamic) equations of a model describing the actual trawl and its rigging. The "user friendly" interface allows the user to iterate "modification and observations" cycles to reach an optimised state of the fishing gear. The process can be used to reduce the...
Tipo: Text
Palavras-chave: Hydrodynamic; Fuel consumption; Simulation; Model; DynamiT; Software; Fishing; Hydrodynamique; Consommation de carburant; Simulation; Modèle; DynamiT; Logiciel; Pêche.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/acte-4613.pdf

Fatty acid profile of fish following a change in dietary fatty acid source: model of fatty acid composition with a dilution hypothesis
Provedor de dados: 5
Autores: Robin, Jean; Regost, Christelle; Arzel, Jacqueline; Kaushik, Sadasivam.
The fatty acid (FA) content of fish is generally said to reflect fatty acid composition of the diet. In fact, incorporation of FA into tissues is modulated by various metabolic factors, and final composition will depend upon the initial FA content, cumulative intake of dietary fatty acids, growth rate and duration. Analysis of time course of changes in FA composition should be easier with animals having different initial FA profiles, which are subsequently fed a diet with the same FA composition.   Data from two studies, one with brown trout and another with turbot were used. Fish were first fed with diets containing one of three different oils (soybean oil (SO), linseed oil (LO) and fish oil (FO)), and subsequently fed the same fish oil-based diet...
Tipo: Text
Palavras-chave: Dietary change; Model; Fish; Fatty acids.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/2003/publication-498.pdf

Kinetics modeling of alginate alkaline extraction from Laminaria digitata
Provedor de dados: 5
Autores: Vauchel, Peggy; Le Roux, Karine; Kaas, Raymond; Arhaliass, Abdellah; Baron, Regis; Legrand, Jack.
Alginates being depolymerized during their alkaline extraction, reducing extraction time could help producing higher rheological quality alginates. The purpose of the present work is to study fresh Laminaria digitata destructuration during alkaline extraction and its link to extraction kinetics. Both alginate extraction yield and mean diameter of algae particles were followed for different values of agitation level and initial size of algae pieces. Results highlighted the existence of a link between extraction yield and algal destructuration. Those elements and the specificity of L. digitata structure have been taken into account to propose a kinetics model based on a fluid-particle reaction with decreasing size particles. The model parameters have been...
Tipo: Text
Palavras-chave: Model; Laminaria digitata; Alkaline extraction kinetics; Alginate.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6315.pdf

Indo-Pacific Sea surface temperature perturbations associated with intraseasonal oscillations of tropical convection
Provedor de dados: 5
Autores: Duvel, Jean Philippe; Vialard, Jerome.
The intraseasonal variability (ISV; 20-90 days) of the SST is examined using 7 yr of data from the Tropical Rainfall Measuring Mission's (TRMM) Microwave Imager ( TMI). The ISV of the SST is larger in the summer hemisphere and in regions of relatively small ocean mixed layer depth (MLD). For these regions, the reddening of the SST spectrum in regard to the surface flux spectrum suggests that the ISV of the SST is mostly controlled by the integration of the local surface forcing by ocean mixed layer. However, the precise origin of large-scale organized perturbations of the SST also depends on region and season. Since the ISV of the convection is an intermittent phenomenon, the local mode analysis (LMA) technique is used to detect only the ensemble of...
Tipo: Text
Palavras-chave: Madden julian oscillation; Western indian ocean; Summer monsoon; Mixed layer; Warm pool; Variability; Fluxes; Model; Atmosphere; Bengal.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/00185/29638/27986.pdf

Modélisation de la croissance des poissons en élevage
Provedor de dados: 5
Autores: Muller-feuga, Arnaud.
After a literature overview of growth models applied to intensively cultured fishes, a new one is proposed for assistance in rearing operations, with following characteristics. A simple and integratable mathematic expression simulates growth while eliminating individual weight influence. It gives way to a specific growth general definition. Temperature action mode on growth speed is simulated by substraction of two exponential functions. An automatic calculation method of thermal parameters is proposed. The torpid action of low temperatures is considered. Feeding ration influences growth through simple rules which are explicitly taken in account by mean of a two parameters function. The other growth factors, more difficult to seize, are expressed through a...
Tipo: Text
Palavras-chave: Modèle; Croissance; Élevage poissons; Pisciculture; Model; Fish culture.; Growth.
Ano: 1990
URL: http://archimer.ifremer.fr/doc/00183/29428/27794.pdf

A model-based evaluation of Marine Protected Areas: the example of eastern Baltic cod (Gadus morhua callarias L.)
Provedor de dados: 5
Autores: Kraus, Gerd; Pelletier, Dominique; Dubreuil, Julien; Moellmann, Christian; Hinrichsen, Hans-harald; Bastardie, Francois; Vermard, Youen; Mahevas, Stephanie.
The eastern Baltic cod stock collapsed as a consequence of climate-driven adverse hydrographic conditions and over fishing and has remained at historically low levels. Spatio-temporal fishing closures [Marine Protected Areas (MPAs)] have been implemented since 1995, to protect and restore the spawning stock. However, no signs of recovery have been observed yet, either suggesting that MPAs are an inappropriate management measure or pointing towards suboptimal closure design. We used the spatially explicit fishery simulation model ISIS-Fish to evaluate proposed and implemented fishery closures, combining an age-structured population module with a multifleet exploitation module and a management module in a single model environment. The model is parameterized...
Tipo: Text
Palavras-chave: Stock recovery; Model; Marine Protected Areas; Fishery management; Baltic cod.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6094.pdf

Fonctionnement hydrodynamique du bassin de Thau. Validation écologique d’un modèle numerique de circulation (programme Écothau)
Provedor de dados: 5
Autores: Millet, B.
The wind-driven flow in the closed bassin de Thau is reproduced with a two-dimensional numerical model of horizontal ciruclation using an Alternate Direction Implicit scheme. A stochastic analysis of frequencies on a yearly time scale of the velocity fields computed in the model and a spatial and stochastic treatment of the term (H2 y2), similar to an effective coefficient of horizontal dispersion by shear effect are presented. This approach will allow the delineation, in a stochastic manner, of the main structures of the circulation in the lagoon and the spatial heterogeneity of its ecohydrodynamic features. Two attempts of analogical research are presented, with sorne examples of the spatial structure in the phytoplankton biomass and the map of the...
Tipo: Text
Palavras-chave: Lagune; Modèle; Circulation; Dispersion; Sédiment; Lagoon; Model; Circulation; Dispersion; Sediment.
Ano: 1989
URL: http://archimer.ifremer.fr/doc/00323/43399/43093.pdf

Les risques conchylicoles en Baie de Quiberon. Première partie : le risque de mortalité virale du naissain d’huître creuse Crassostra gigas. Rapport final du projet Risco 2010-2013
Provedor de dados: 5
Autores: Mazurie, Joseph; Stanisiere, Jean-yves; Langlade, Aime; Bouget, Jean-francois; Dumas, Franck; Treguier, Cathy; Leclerc, Emilie; Ravaud, Emilie; Quinsat, Kevin; Gabellec, Raoul; Retho, Michael; Cochet, Helene; Dreano, Alain.
This study (“Risco”), implicating both industry, socio-economic experts and biologists, was funded by the Regional Council of Brittany, for 3 years (2010-2013), to investigate upon the origin of oysters (Crassostrea gigas) mortalities in the bay of Quiberon (South Brittany, France). Specific mortalities of adult oysters were recorded in this bay in 2006, whereas mortalities of one year old spat were observed since in 2008 in this bay as at a national scale. The experimental protocol in 2010, including a monthly survey of oyster batches at 15 experimental stations, allowed to assess the risk for one-year oysters, due to viral disease. A clear spatial distribution of this risk was evidenced, with a western area spared from contamination and mortality, and a...
Tipo: Text
Palavras-chave: Baie de Quiberon; Crassostrea gigas; Mortalité; Herpès-virus; OsHV-1; Épidémiologie; Modèle.; Quiberon bay; Crassostrea gigas; Mortality; Herpes-virus; OsHV-1; Epidemiology; Model.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00179/29043/27528.pdf

Interacting effects of Hydrobia ulvae bioturbation and microphytobenthos on the erodibility of mudflat sediments
Provedor de dados: 5
Autores: Orvain, Francis; Sauriau, Pierre-guy; Sygut, A; Joassard, Lucette; Le Hir, Pierre.
Microphytobenthos-macrofauna sediment interactions and their effects on sediment erodability were examined in laboratory experiments. Sediment beds were manipulated in a tidal mesocosm to produce diatom mats in exponential or in stationary phases of development after 6, 8 or 11 d of culture. These sediment beds were used in flume experiments to investigate the influence of bioturbation by the gastropod Hydrobia ulvae on both sediment and pigment resuspension as a function of the physiological state of the microphytobenthic mats. In most experiments, only a surface layer was resuspended. A model was used to analyse in detail the contribution of each variable to this surface-layer erosion. Bioturbation was the major factor controlling resuspension, and its...
Tipo: Text
Palavras-chave: Sediment; Bioturbation; Erosion; Model; Hydrobia ulvae; Physiological state; Microphytobenthos; Resuspension.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/publication-3780.pdf

Modélisation des blooms de Gymnodinium mikimotoï le long de la façade atlantique française : répartition spatiale
Provedor de dados: 5
Autores: Loyer, Sophie; Lazure, Pascal; Gentien, Patrick; Menesguen, Alain.
In order to study the occurrence of Gymnodinium mikimotoï bloom on the French Atlantic coast, a three-dimensional model of primary production was set up. The biological model was coupled to a hydrodynamic model previously developed at Ifremer, by the intermediary of transport, diffusion and heat fluxes. The cycles of three limiting elements for the phytoplankton growth were modelised: nitrogen, phosphorus and silicon. The second phase of the study aimed at reproducing the summer dinoflagellate blooms. In this new approach a model of the species Gymnodinium mikimotoï was coupled with the previous biomass model which provides the physical and chemical environments. The study focuses on the results obtained by this specific sub-model. The parametrisation was...
Tipo: Text
Palavras-chave: Turbulence; Dinoflagellés; Gymnodinium mikimotoï; Modèle; Nutriments; Turbulence; Dinoflagellate; Gymnodinium mikimotoï; Model; Nutrients.
Ano: 2001
URL: https://archimer.ifremer.fr/doc/00479/59100/61738.pdf

Large gas hydrate accumulations on the eastern Nankai Trough inferred from new high-resolution 2-D seismic data
Provedor de dados: 5
Autores: Nouze, Herve; Henry, P; Noble, M; Martin, V; Pascal, G.
Previous studies have revealed the presence of a widespread Bottom Simulating Reflector (BSR) on the eastern Nankai slope, as well as the occurrence of enigmatic high amplitude reflections that extend well above the BSR. New high-resolution 2-D seismic data were collected on the eastern Nankai slope, during the French-Japanese SFJ cruise in year 2000 and AVA analyses of the enigmatic reflectors are conducted. At the studied location, these analyses suggest that high amplitude anomalies above the BSR delineate the top of gas hydrate rich sediments. Several tens % of the sediment porosity would be filled with gas hydrates between the BSR and a sharp boundary 30 to 60 m above. To account for these observations, we propose that an invasion by free gas of the...
Tipo: Text
Palavras-chave: Zone; Model; Ridge; Methane gas; Marine sediments.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/publication-510.pdf

Modelling the accumulation of PSP toxins in Thau Lagoon oysters (Crassostrea gigas) from trials using mixed cultures of Alexandrium catenella and Thalassiosira weissflogii
Provedor de dados: 5
Autores: Lassus, Patrick; Amzil, Zouher; Baron, Regis; Sechet, Veronique; Barille, Laurent; Abadie, Eric; Bardouil, Michele; Sibat, Manoella; Truquet, Philippe; Berard, Jean-baptiste; Gueguen, Marielle.
In October and November 2003 a bloom of the toxic dinoflagellate Alexandrium catenella was observed in the North-east zone of Thau lagoon (French Mediterranean coast). Sea water samples were collected every hours to evaluate time-related variations of phytoplankton concentrations and to compare the relative ratio of A. catenella versus other phytoplankton species during the outbreak. From these observations, trials using recirculated sea water systems were performed to: i) evaluate the physiological effects on oyster of increasing proportions of A. catenella within a mixed microalgal diet where the non-toxic diatom Thalassiosira weissflogii was present at concentration: 1500 cells ml(-1), ii) compare the effect of two temperatures (12 degrees C and 18...
Tipo: Text
Palavras-chave: Mediterranean Sea; Alexandrium catenella; Toxin content; Model; Crassostrea gigas; Paralytic shellfish poisoning.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2624.pdf

Atlantic meridional overturning circulation and the Southern Hemisphere supergyre
Provedor de dados: 5
Autores: Speich, Sabrina; Blanke, Bruno; Cai, Wenju.
The ocean's role in climate manifests itself through its high heat capacity, its own rich internal dynamics and its ability to transport vast quantities of heat and freshwater. Of particular interest is the global ocean circulation associated with the Atlantic meridional overturning (AMOC). Because observations are sparse, the detailed global structure of the AMOC remains poorly understood, particularly the pathways along which water returns to the Atlantic to compensate the export of North Atlantic Deep Water (NADW). Here we provide the first quantitative 3-dimensional global view of the AMOC using a Lagrangian reconstruction which integrates hundred of thousands water particle trajectories in an ocean model. The resulting pattern elucidates the role of...
Tipo: Text
Palavras-chave: Antarctic circumpolar current; Indian ocean; Intermediate water; Thermohaline circulation; Pacific oceans; Conveyor belt; Model; Transport; Tracers.
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00203/31420/29821.pdf

Some notes on taxonomic methodology
Provedor de dados: 16
Autores: Hammen, L. van der.
The present paper constitutes an introduction to taxonomic methodology. After an analysis of taxonomic practice, and a brief survey of kinds of attributes, the paper deals with observation, description, comparison, arrangement and classification, hypothesis construction, deduction, model, experiment, abstraction, and synthesis. The methodological aspects of the species-concept and of biological classification are dealt with in two final sections.
Tipo: Article / Letter to the editor
Palavras-chave: Abstraction; Classification; Comparison; Deduction; Description; Experiment; Hypothesis; Methodology; Model; Observation; Species-concept; Synthesis; Systematics; Taxonomy; 42.03; 42.70.
Ano: 1986
URL: http://www.repository.naturalis.nl/record/318283

A new innovated and cheep model in building artificial reefs
Provedor de dados: 20
Autores: Mahmoud, M.A.; Ammar, M.S.A.
A novel and cheep approach for building artificial reefs was designed in such a way that sediments in an area of high sedimentation rate will be utilized in building the artificial substrate with no further sediment accumulation afterwards. The model consists of several steel cylinders which are soldered together in such a way to form a reef flat, a gentle slope and a steep slope, with two layers of narrow opening meshes (a lower plastic and an upper metallic one). Within a short periode (3 months), a substrate layer of a total of ~ 1 cm was formed between the two meshes, this layer increased to ~2 cm after 9 months. Transplants of the three species Stylophora pistillata, Echinopora gemmacea and Montipora spongiosa grow better when the attaching surface is...
Tipo: Journal Contribution
Palavras-chave: Coral reefs; Artificial coral reefs; Transplantation; Substrate; Model; Sedimentation Sediment transport Artificial reefs.
Ano: 2005
URL: http://hdl.handle.net/1834/1298

Modelling the influence of ecological interactions on reactive transport processes in sediments
Provedor de dados: 27
Autores: Meysman, F.
Within the natural sciences, it has long been recognized that biological activity can modify the texture, structure and composition of surface sediments. Darwin (1881) already examined the stirring of soils by burrowing earthworms and made detailed observations on how these organisms affect soil processes. A similar phenomenon can be observed in aquatic sediments, which are inhabited by a diverse biological community, supported by the flux of organic matter and oxygen from the overlying water column. Surface sediments of oceans, estuaries, lakes and rivers are highly active biogeochemical environments and an effective way to generate insight in the complexity of the interactions is by means of so-called general early diagenetic models (e.g. Soetaert et al,...
Tipo: Info:eu-repo/semantics/doctoralThesis
Palavras-chave: Chemistry; Ecology; Hydrology; Model; Sediment; Water.
Ano: 2001
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8063

Equations for estimating biomass of aereal compartementes of Eucalyptus benthamii
Provedor de dados: 190
Autores: Silva, Helton Damin da; Ferreira, Carlos Alberto; Corrêa, Robson Schaff; Bellote, Antonio Francisco Jurado; Tussolini, Elson Luiz.
This paper presents the results of the adjustment of equations for estimating biomass of aerial compartments of Eucalyptus benthamii trees. The percentile allocation of biomass, in the compartments wood, bark, leaves and branches is also presented. The trees of Eucalyptus benthamii were sampled from stands of 12, 24, 36 and 48 months of age, planted at the spacing 3 m x 2 m, in the region of Guarapuava-PR. For the compartments considered, the generalized logarithmic model gave better indices of adjustment for branches and, together with logarithmic combined variable, the minor error for bark variable. Leaves and wood had minor error with model lnY=b0 +b1*lnDBH and logarithmic combined variable, respectively. The allocation of biomass in the different...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Age; Model; Variable Idade; Modelos; Variável.
Ano: 2004
URL: http://pfb.cnpf.embrapa.br/pfb/index.php/pfb/article/view/1588

Forecasting of the annual yield of Arabic coffee using water deficiency
Provedor de dados: 86
Autores: Aparecido,Lucas Eduardo de Oliveira; Rolim,Glauco de Souza.
Abstract: The objective of this work was to develop agrometeorological models for the forecasting of the annual yields of Arabic coffee (Coffea arabica), using monthly water deficits (DEFs) during the coffee cycle, in important locations in the state of Minas Gerais, Brazil. For the construction of the models, a meteorological data set spanning of 18 years and multiple linear regressions were used. The models were calibrated in high- and low-yield seasons due to the high-biennial yields in Brazil. All calibrated models for high- and low-yield seasons were accurate and significant at 5% probability, with mean absolute percentage errors ≤2.9%. The minimum forecasting period for yield is six months for southern Minas Gerais and Cerrado Mineiro. In high-yield...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Coffea arabica; Agrometeorology; Climate; Forecasting; Model; Water balance.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2018001201299

A TRADE LIBERALIZATION IN INTERNATIONAL DAIRY MARKETS
Provedor de dados: 31
Autores: Langley,   Suchada V.; Blayney,   Donald P.; Stout,   Jim; Somwaru,   Agapi; Normile,   Mary Anne; Miller,   James J.; Stillman,   Richard.
International dairy industries remain among the most distorted agricultural sectors. Dairy average bound tariffs remain among the highest of all agricultural commodities, and dairy trade is characterized by a large number of megatariffs and tariff-rate quotas (TRQs). The objective of our study is to examine how the international dairy markets might respond to policy changes under various assumptions, using a partial equilibrium, multiple-commodity, multiple-region model of agricultural policy and trade.  Our results indicate that liberalization will reduce supplies, increase dairy trade, and raise world prices.
Tipo: Conference Paper or Presentation
Palavras-chave: Dairy Markets; Trade Liberalization; Model; Policy; International Relations/Trade.
Ano: 2003
URL: http://purl.umn.edu/21997

Revisiting Malthus in Light of Agricultural Biotechnology
Provedor de dados: 31
Autores: Mock,   J.N.; Epperson,   James E.
While the population of the world is continually growing, there are doubts that the food supply will be sufficient to keep pace.  Although 14% of the world is undernourished today, an exponentially increasing population could be catastrophic if agricultural production lags too far behind.  This paper attempts to forecast agricultural yield given the recent advent of genetically modified crops as a means to see whether this technology has the potential to help supply the world with food in the future.  Through regression, a model was developed to make predictions of corn yields as a case study on how biotechnology might affect future agricultural production.
Tipo: Working or Discussion Paper
Palavras-chave: Yield; Future; Prediction; Model; Agricultural and Food Policy; Crop Production/Industries; Food Security and Poverty.
Ano: 2008
URL: http://purl.umn.edu/45613

THE USE OF MODELS IN OPTIMIZING THE FIELD CROP PRODUCTION IN AGRICULTURAL ENTERPRISE-MBA Thesis
Provedor de dados: 31
Autores: Muncan,   Mihajlo.
The full use of resource capacities of agricultural enterprises favorably affects the general increase in economic efficiency and rational production making them more competitive in the market. This creates the need for constant improvement of business strategies that uses all available resources to create the most profitable production. The main objective of this study was to find the ideal structure of production in agricultural enterprise and to enable the realization of maximum profit using the available production resources (land, mechanization, labor forces). As the basic method of planning, this study used the simplex method of linear programming which gives the most profitable sowing structure after detailed analysis of resources and achieved...
Tipo: Thesis or Dissertation
Palavras-chave: Model; Agricultural enterprises; Resources; Profit; Crop Production/Industries; Research Methods/ Statistical Methods.
Ano: 2010
URL: http://purl.umn.edu/91118

THE ROLE OF SKILLS AND COMPETENCES IN THE NATIONAL HIGHER EDUCATION AND IN THE LABOUR MARKET
Provedor de dados: 31
Autores: Herneczky,   Andrea; Varga,   Erika; Marsalek,   Sandor.
Due to the rapid technological, technical and economic development in the 21st century, knowledge and learning have become decisive economic factors and the role of human resources has also come in the limelight. The competitiveness of an entire national economy, a region or even a continent is basically determined by human resources with the suitable competencies. The labour market is in need of graduates who possess not only expertise in its strict sense but also master some economic, IT and foreign language skills. The free movement of labour is only of benefit to those who are able to communicate in a foreign language at a suitable level in addition to having specialised knowledge.  We set out to carry out a questionnaire-based study to prove that...
Tipo: Journal Article
Palavras-chave: Competence; Competitiveness; Human resources; Model; Education; Labour market; Kompetencia; Versenyképesség; Emberi erőforrás; Modell; Oktatás; Munkaerőpiac; Teaching/Communication/Extension/Profession.
Ano: 2010
URL: http://purl.umn.edu/99203

An Analysis of Global Timber Markets
Provedor de dados: 31
Autores: Sohngen,   Brent; Mendelsohn,   Robert; Sedjo,   Roger A.; Lyon,   Kenneth S.
This paper presents a model of global timber markets that captures the evolution of a broad array of forest resources and timber market margins over time. These margins include the inaccessible northern and tropical margins, plantation establishment, and timberland management. A baseline case is presented and discussed. Five alternative scenarios are then presented. These scenarios allow us to consider several important questions about timber market behavior and the future supply of industrial fiber: (1) What happens along the northern and the tropical inaccessible margins? (2) What role do timber plantations play? and (3) How do shifts in management intensity interact with market forces? The baseline case suggests that both prices and harvests rise over...
Tipo: Working or Discussion Paper
Palavras-chave: Global timber markets; Forest plantations; Model; Forecast; Resource /Energy Economics and Policy; Q10; Q21; Q23; Q24.
Ano: 1997
URL: http://purl.umn.edu/10449

Empirical Analysis on Brand Extension Size Model Based on Ecological Characteristics
Provedor de dados: 31
Autores: Yu,   Yun-bo; Yu,   Lin.
Firstly, the paper establishes a brand-extension size model and adopts the marginal analysis to analyze the optimal solution of it. Secondly, research the brand-extension condition of G brand by questionnaire survey. There are 240 questionnaires handed out, with 211 withdrawing and 187 valid, by doing this to test the influencing degree of each factor in brand-extension size model; At the same time, use analytic hierarchy process to analyze the size of brand extension and principal component analysis to find out the main factors that influence brand extension of G brand. Finally, the paper makes an empirical analysis on brand extension size model based on ecological characteristics, the results show that the order of the total information reflected by each...
Tipo: Journal Article
Palavras-chave: Model; Size; Demonstration; Brand extension; Ecological characteristics; China; Agribusiness.
Ano: 2009
URL: http://purl.umn.edu/93462

LOCATION OF VERTICALLY LINKED INDUSTRIES UNDER FREE TRADE: CASE STUDIES OF ORANGE JUICE AND TOMATO PASTE IN THE WESTERN HEMISPHERE
Provedor de dados: 31
Autores: Hartman,   Darcy A.; Sheldon,   Ian M.; Tweeten,   Luther G.
The objective of this study was to determine the economic impact on the United States of removing tariff barriers on imports of concentrated orange juice and tomato paste from South America.  The study highlighted an agglomeration model of industry location recognizing imperfect competition and increasing returns.  The results were contrasted with those from a competitive model with conventional estimates of supply and demand elasticities.  Because the assumptions of the models differed, the results also differed.  The agglomeration model indicated that the United States would gain market share of production and processing with the removal of tariffs.  In contrast, the competitive model indicated that the United States would lose market share in production...
Tipo: Working or Discussion Paper
Palavras-chave: Oranges; Tomatoes; Juice; Paste; Model; Agglomeration; Competitive; Comparative advantage.; Industrial Organization; International Relations/Trade.
Ano: 1999
URL: http://purl.umn.edu/14580

THE IMPLICATIONS OF THE WTO NEGOTIATIONS ON THE CANADIAN CHICKEN MARKET: TWO REPRESENTATIONS OF CHICKEN AND STOCHASTIC WORLD PRICES
Provedor de dados: 31
Autores: Rafajlovic,   Juanita; Cardwell,   Ryan T.
Current Doha Development Agenda (DDA) World Trade Organisation negotiations include proposals that would affect the trade barriers that protect Canada’s chicken producers from foreign competition. This research analyses the effects of the most recent proposals to emerge from the DDA negotiation on Canada’s chicken industry. We develop a partial-equilibrium model that generates welfare effects for the Canadian chicken industry supply chain. We also introduce stochastic prices to evaluate the effects of world price instability on the Canadian chicken industry. The model is also adapted to represent chicken as two distinct products; white meat and dark meat. Simulation results suggest that the welfare effects of the DDA proposals on the Canadian chicken...
Tipo: Report
Palavras-chave: WTO; Chicken; Canada; Model; Trade; Agricultural and Food Policy; Demand and Price Analysis; International Relations/Trade.
Ano: 2010
URL: http://purl.umn.edu/95814

INTEGRATING BIOMASS TO PRODUCE HEAT AND POWER AT ETHANOL PLANTS
Provedor de dados: 31
Autores: De Kam,   Matthew J.; Morey,   R. Vance; Tiffany,   Douglas G.
Published in:  Applied Engineering in Agriculture, Vol. 25(2): 227‐244
Tipo: Journal Article
Palavras-chave: Biomass; Renewable; Sustainable; Model; Gasification; Combustion; Emissions; Ethanol production; Combined heat and power; Resource /Energy Economics and Policy.
Ano: 2009
URL: http://purl.umn.edu/93631

Necessity and Model of the Nationalization of Rural Elites
Provedor de dados: 31
Autores: Yu,   Yang.
Concept of rural elite in China is introduced. And rural elites are classified into governing elite, economic elite, social elite and cultural elite with phenomenon of overlapping among the four types. Definitions of science nationalization and elite politicalization are introduced. Based on the review of previous research results, meaning of elite nationalization is defined: the state guides elites to join in its operation by means of controlling the elites’ occupation, promoting their status, improving their warfare, assimilating their thought and so on, so that elites may serve the political objectives of the state. Predicaments of rural elites are analyzed. Firstly, some rural governing elites and economic elites are high combined, or they use each...
Tipo: Thesis or Dissertation
Palavras-chave: Rural elites in China; Nationalization of elites; Necessity; Model; Labor and Human Capital.
Ano: 2009
URL: http://purl.umn.edu/54035

The Project System Improvement and Innovation Strategy
Provedor de dados: 31
Autores: Parnell,   Peter F.; Clark,   Richard A.; Timms,   Janice.
The purpose of the Project System Improvement and Innovation Strategy is to ensure regular and frequent improvement and innovation of the design, leadership and performance of the project system and its component elements, and to manage the interaction between the project system and the broader meta-system. The importance of this strategy has become more apparent over the past year. Initially it was treated as a 'supporting' strategy, but with time, recognition of its importance is growing. This strategy will require greater ingenuity and attention over the next two years to ensure project success, efficiency and sustainability.
Tipo: Article
Palavras-chave: Sustainable improvement and innovation; Model; System; Strategy; Farm Management.
Ano: 2008
URL: http://purl.umn.edu/121991

THE USE OF MODELS IN OPTIMIZING THE FIELD CROP PRODUCTION IN AGRICULTURAL ENTERPRISE
Provedor de dados: 31
Autores: Muncan,   Mihajlo.
The full use of resource capacities of agricultural enterprises favorably affects the general increase in economic efficiency and rational production making them more competitive in the market. This creates the need for constant improvement of business strategies that uses all available resources to create the most profitable production. The main objective of this study was to find the ideal structure of production in agricultural enterprise and to enable the realization of maximum profit using the available production resources (land, mechanization, labor forces). As the basic method of planning, this study used the simplex method of linear programming which gives the most profitable sowing structure after detailed analysis of resources and achieved...
Tipo: Journal Article
Palavras-chave: Model; Agricultural enterprises; Resources; Profit; Agribusiness.
Ano: 2011
URL: http://purl.umn.edu/104681

A SYSTEM DYNAMICS MODEL OF AGRICULTURE AND RURAL DEVELOPMENT: THE TOPMARD CORE MODEL
Provedor de dados: 31
Autores: Johnson,   Thomas G.; Bryden,   John Marshall; Refsgaard,   Karen; Alva Lizarraga,   Sara.
The goal of the TOPMARD project is to develop a model of agriculture and rural development to better understand the agronomic, ecological, economic and social dimensions of rural regions. The resulting model, (Policy Model of Multifunctional Agriculture and Rural Development) was built collaboratively and hierarchically by the research teams from the 11 countries. The model features eight subsectors (Land, Agriculture, Tourism, Region, Human Resources, Non-commodities, Capital, and Quality of Life). Imbedded in the model are a complete dynamic input-output model, and an agecohort education demographic model. The model has both supply-side and demand-side drivers. Land use is the key supply-side driver. Land use, coupled with production system choices,...
Tipo: Conference Paper or Presentation
Palavras-chave: Multifunctionality; System dynamics; Policy; Model; Rural development; Community/Rural/Urban Development; Research Methods/ Statistical Methods; Research and Development/Tech Change/Emerging Technologies.
Ano: 2008
URL: http://purl.umn.edu/6497

AZ ÖKOLÓGIAI MÓDON MŰVELT TERMŐTERÜLETEK NAGYSÁGÁT BEFOLYÁSOLÓ TÉNYEZŐK ÉS AZ ÁRUTERMELŐ NÖVÉNYEK PIACI POZICIÓI MAGYARORSZÁGON
Provedor de dados: 31
Autores: Jarasi,   Eva Zsuzsanna.
The significance of organic farmlands can be evaluated in two ways: based on their ecological and their economic implications. Regarding the former, it does not make a crucial difference how the land is utilised specifically: pasture and meadow; arable land or plantation or certified organic farmland, use not known. For an illustration, let us consider that in 2005, almost half of organic farmlands in the world were located in Australia, amounting to over 31 million hectares. Most of this area is pastoral land for low intensity grazing in Australia. Therefore, one organic hectare in Australia is not directly equivalent to one organic hectare in Denmark, for example, due to its level of productivity. As a result, it is worthwhile to survey the exact extent...
Tipo: Book
Palavras-chave: Ökológiai növénytermesztés; Fejlődési lehetőség; Modellezés; Pareto-elv; Organic crop production; Possibility for development; Model; Pareto principle; Agribusiness; Crop Production/Industries; Farm Management.
Ano: 2008
URL: http://purl.umn.edu/43327

MODELING WORLD PEANUT PRODUCT MARKETS: A TOOL FOR AGRICULTURAL TRADE POLICY ANALYSIS
Provedor de dados: 31
Autores: Beghin,   John C.; Matthey,   Holger.
This paper presents a new partial-equilibrium, multi-market international model developed to analyze policies affecting peanut products markets. The model covers four goods (food-quality peanuts, crush-quality peanuts, peanut oil, and groundnut cake) in 13 countries/regions (Argentina, Canada, China, the EU-15, the Gambia, India, Malawi, Mexico, Nigeria, Senegal, South Africa, the United States, and Rest of World). Welfare is evaluated by looking at consumers' equivalent variation, quasi-profits in farming (peanut farming, livestock), quasi-profits in crushing, and taxpayers' revenues and outlays implied by distortions. We calibrate the model for three recent years (1999/2000, 2000/01, and 2001/02) on historical data. We illustrate the model's...
Tipo: Working or Discussion Paper
Palavras-chave: Agricultural trade policy analysis; Crush; Doha; Groundnut; Model; Oil; Peanuts; Agricultural and Food Policy; Crop Production/Industries.
Ano: 2003
URL: http://purl.umn.edu/18618

The Sustainable Improvement and Innovation Model
Provedor de dados: 31
Autores: Clark,   Richard A.; Timms,   Janice; Parnell,   Peter F.; Griffith,   Garry R.
The Beef CRC's 'Sustainable Beef Profit Partnerships' (BPP) project is built around the Sustainable Improvement and Innovation (SI&amp;I) Model – a model for the design, leadership and management of projects to achieve rapid and sustained improvement and innovation, and accelerated adoption. The model is implemented through a systemic approach to project design, and the development of a number of integrated strategies to guide the targeting of priority outcomes and work plans. The emphasis is on a sustainable project methodology such that the intended outcomes can continue to be delivered long after the Beef CRC funding is terminated. Further, there is an emphasis on rapid implementation of the process in the short-term such that outcomes can be generated...
Tipo: Article
Palavras-chave: Sustainable improvement and innovation; Model; System; Strategies; Farm Management.
Ano: 2008
URL: http://purl.umn.edu/121990

Research on Site Selection Model of Distribution Center of Agricultural Products
Provedor de dados: 31
Autores: Li,   Yong-xin; Yin,   Chun-wu; Hui,   Xiao-jian.
In the light of the practical situation of logistics distribution of agricultural products, we primarily select transportation factor, economic factor, environment factor, and other factors, to establish evaluation index system of site selection of distribution center of agricultural products. And then we adopt the analytic hierarchy process method to calculate weight of site selection of distribution center of agricultural products. Under the circumstance that the evaluation information is interval number, we use uncertain and multiple attribute decision making method to establish site selection model of distribution center of agricultural products. Finally, taking one city as an example, we discuss the application of this model in site selection of...
Tipo: Journal Article
Palavras-chave: Distribution center of agricultural products; Model; Interval number; China; Agribusiness.
Ano: 2011
URL: http://purl.umn.edu/113502

VIDÉKI VERSENYKÉPESSÉG – VERSENYKÉPES VIDÉKFEJLESZTÉS (AVOP INTÉZKEDÉSEK ÉS AZOK KOMMUNIKÁCIÓJÁNAK VIZSGÁLATA)
Provedor de dados: 31
Autores: Szeles,   Ivett.
In the period of 2004-2006 of the OPARD, Hungary had an amount of HUF 107.8 billion, which was divided through three priorities, and inside these priorities there were ten actions. Through the use of the comparative advantages, the OPARD considers that the improvement of the agricultural production effectiveness, as well as the competitiveness and income security are important. In the areas which are less suitable for competitive economic improvement, it provides sustainable, multifunction agriculture, and the foundation of the conditions of the associated activities. The objective of my thesis is to analyse the measurements by examining their intensity and examining the accepted and refused applications, together with the communication monitoring of these...
Tipo: Book
Palavras-chave: Támogatás; Komparatív előnyök; Modellezés; Szaktanácsadás; Subsidies; Comparative advanteges; Model; Extension service; Agricultural and Food Policy; Community/Rural/Urban Development; Productivity Analysis.
Ano: 2008
URL: http://purl.umn.edu/43319

Analysis of Effects of Different Operation Patterns of Returning Farmland to Forest(grass) on Rural Economy-A Case of Wuqi County, China
Provedor de dados: 31
Autores: Meng,   Luo; Gui-xian,   Li.
Taking Wuqi country, shanxi Province as an example, this paper is based on the introductions of the researched regions and according to the planting model and some factors influencing economy. After systematic analysis and selection, it selects ecological forestry, wood-grass-husbandry, wood-grass-husbandry, wood-medicine, economic forestry and greenhouse vegetable these five models of returning farming to grass, with Wuqi town, Baibaotown, Wu Cangbao county, Xinzhai county, Xuecha county and Wugu town these five sites as examples. This paper has carried out a research on these 5 models at country, town and household levels through Participatory Rural Appraisal and Document Search to gain the related data. And making a comparison on the contribute of the 5...
Tipo: Journal Article
Palavras-chave: Agribusiness; Model; Wuqi county; Returning farmland to forest and grassland; Economic; Efficiency; China.
Ano: 2010
URL: http://purl.umn.edu/93231

How do affective health-related and cognitive determinants influence fish consumption? A consumer survey in five European countries
Provedor de dados: 31
Autores: Pieniak,   Zuzanna; Verbeke,   Wim; Scholderer,   Joachim; Brunso,   Karen; Olsen,   Svein Ottar.
This paper focuses on exploring whether and to what extent affective health-related and cognitive determinants have an impact on fish consumption behaviour. Cross-sectional data were collected through the SEAFOODplus pan-European consumer survey (n=4,786) with samples representative for age and region in Belgium, the Netherlands, Denmark, Spain and Poland. Consumers’ belief that eating fish is healthy and their interest in healthy eating positively influence fish consumption behaviour. Subjective knowledge is found to be a more important predictor of fish consumption than objective knowledge. Age and education contribute significantly to explaining fish consumption behaviour. However, the age and education effects on fish consumption frequency are indirect...
Tipo: Conference Paper or Presentation
Palavras-chave: Consumer; Fish; Determinants; Model; Food Consumption/Nutrition/Food Safety.
Ano: 2008
URL: http://purl.umn.edu/44326

Impacts of Decoupling and Milk Quota Trade on the French and German Dairy Sectors
Provedor de dados: 31
Autores: Huettel,   Silke; Kleinhanss,   Werner; Offermann,   Frank.
This paper analyses the impacts of the 2003 CAP reform and of milk quota trade at the national level. To this end, a mathematical programming model has been further developed for Germany and extended to other main milk-producing EU member states like France. Homogeneous farm groups are built on the basis of EU Farm Accountancy Data Network. The results show that quotas will be fully used in both countries if quota trade is possible. A clear tendency in the reallocation of production from small towards large farms can be seen in all regions for France. In Germany, the redistribution of direct payments induced by the implementation of the regional scheme of decoupled payments leads to higher reductions of income in dairy &amp; beef farms than in France.
Tipo: Conference Paper or Presentation
Palavras-chave: 2003 CAP reform; Milk quota trade; Model; Mathematical programming; International Relations/Trade.
Ano: 2005
URL: http://purl.umn.edu/24731

Sectoral Production Function of Chicken Broiler Fattening
Provedor de dados: 31
Autores: Maier,   Tomas; Pankova,   Ludmila.
The function was formed on the basis of sectional data from seven Czech businesses using data from seven to eight annual observations. The Least Square Dummy Variable Model was used to estimate the power function. The information presented in the article is the product of working on the Institutional Research Plan MSM 6046070906, "The Economics of Czech agriculture resources and their efficient use within a multifunctional agri-food systems framework".
Tipo: Journal Article
Palavras-chave: Production Function; Broiler Chicken; Model; Food Consumption/Nutrition/Food Safety; Production Economics; Resource /Energy Economics and Policy; GA; IN.
Ano: 2010
URL: http://purl.umn.edu/99068

MODELO DE REGLAMENTO PARA LA ADMINISTRACIÓN DE UN RASTRO MUNICIPAL A NIVEL NACIONAL
Provedor de dados: 31
Autores: Cabral Martell,   Agustin; Aguilar Valdes,   Alfredo; Alvarado Martinez,   Luis Felipe; Alvarado Martinez,   Tomas Everardo.
They are few the rakes of the country that have the modern technology and the personnel qualified to carry out the humanitarian sacrifice as it indicates it the Federal Law of Animal Sanity. (DOF. 23-July-2007). Really the only dependence or association that he/she has had interest and he/she has been in charge of seriously of supervising that the slaughter is carried out in a humanitarian way, it is the denominated civil association ANPALPA A.C (National Association for the Application of Laws of Protection to the Animals) that has taken the initiative to introduce the methods of humanitarian sacrifice in near 400 rakes and slaughterhouses of the country; and it is unlikely that the corresponding authorities (SAGARPA and HEALTH), have not taken the...
Tipo: Journal Article
Palavras-chave: Model; Regulation; Administration; Municipal rake; National level.; Agribusiness.
Ano: 2010
URL: http://purl.umn.edu/56555

Estimating Carbon Supply Curves for Global Forests and Other Land Uses
Provedor de dados: 31
Autores: Sedjo,   Roger A.; Sohngen,   Brent; Mendelsohn,   Robert.
This study develops cumulative carbon 'supply curves' for global forests utilizing an dynamic timber supply model for sequestration of forest carbon. Because the period of concern is the next century, and particular time points within that century, the curves are not traditional Marshallian supply curves or steady-state supply curves. Rather, the focus is on cumulative carbon cost curves (quasi-supply curves) at various points in time over the next 100 years. The research estimates a number of long-term, cumulative, carbon quasi-supply curves under different price scenarios and for different time periods. The curves trace out the relationship between an intertemporal price path for carbon, as given by carbon shadow prices, and the cumulative carbon...
Tipo: Working or Discussion Paper
Palavras-chave: Carbon supply curves; Sequestration; Timber; Forests; Model; Global warming; Prices; Markets; Resource /Energy Economics and Policy; Q10; Q15; Q21; Q23; Q24.
Ano: 2001
URL: http://purl.umn.edu/10663

Evaluation of approaches to control of Maedi-Visna disease of sheep using a Markov chain simulation model for a range of typical British Flocks
Provedor de dados: 31
Autores: Stott,   Alistair W.; Milne,   Catherine E.; Gunn,   George J.
An epidemiological model is described that closely mimicked results of a published serological study of natural transmission of Maedi-Visna virus in a low ground flock of sheep. We adjusted parameters in the model from this baseline to explore the possible implications for the control of Maedi-Visna virus in typical British flocks. On closed hill farms, low probability of effective contact was most critical for control. In open low ground flocks, purchasing accredited replacements eliminated disease spread, otherwise flock size was the most important factor governing flock prevalence. Results highlighted the need for more epidemiological information about Maedi-Visna, particularly whether hill farms act as a hidden reservoir of virus or reduce the impact...
Tipo: Working or Discussion Paper
Palavras-chave: Livestock Production/Industries; Maedi-Visna; Model; Markov Chain; Sheep; Control.
Ano: 2009
URL: http://purl.umn.edu/61102

The “Rural-Sensitive Evaluation Model” for evaluation of local governments’ sensitivity to rural issues in Serbia
Provedor de dados: 31
Autores: Win,   Heijman; Milic,   Branislav B.; Bogdanov,   Natalija.
In the search for an adequate set of indicators to measure the level of pro-rural aspirations of Local Governments (LG), the main existing approaches to endogenous development have been examined. However, the conclusion must be that none of them seem to fit the needs completely. For this reason, a new index, the Municipal Rural-Sensitive Index (MRSI), has been developed, representing the base for the Rural Sensitive Evaluation Model (RSEM). The MRSI integrates the key features of the LEADER (Liaison Entre Actions de Développement Rural) philosophy, consisting of 41 rural-sensitive indicators, grouped into 3 categories and 7 sub-categories. The resulting MRSI scores allow a quick comparison between LGs, show changes over time and assists in establishing a...
Tipo: Conference Paper or Presentation
Palavras-chave: Evaluation; Model; LEADER; Local Government; Agricultural and Food Policy; C52; C54; H11; O21; R58.
Ano: 2011
URL: http://purl.umn.edu/99417

EU-China Agricultural Trade in Relation to China's WTO Membership
Provedor de dados: 31
Autores: Niemi,   Jyrki S.; Huan-Niemi,   Ellen.
China's trade with the world doubled after joining the WTO. This study attempts to identify and measure quantitatively the effects of changing economic environment and trade policies on China's global agricultural imports as well as imports from the EU. The approach is to model behavioral relationships in the agricultural trade between China and the EU by using annual trade data from 1986 to 2005. The results indicate that Chinese agricultural imports are relatively inelastic to absolute price changes, but relative price changes significantly affect the market shares of EU exports due to price competition. Trade liberalization in the form of tariff reductions is trivial in changing the quantity of China's agricultural imports from the EU. Rapid income...
Tipo: Journal Article
Palavras-chave: China; EU; WTO; Agricultural imports; Income; Tariff; Price; Model; International Relations/Trade.
Ano: 2007
URL: http://purl.umn.edu/8163

QIC program and model selection in GEE analyses
Provedor de dados: 31
Autores: Cui,   James.
The generalized estimating equation (GEE) approach is a widely used statistical method in the analysis of longitudinal data in clinical and epidemiological studies. It is an extension of the generalized linear model (GLM) method to correlated data such that valid standard errors of the parameter estimates can be drawn. Unlike the GLM method, which is based on the maximum likelihood theory for independent observations, the GEE method is based on the quasilikelihood theory and no assumption is made about the distribution of response observations. Therefore, Akaike’s information criterion, a widely used method for model selection in GLM, is not applicable to GEE directly. However, Pan (Biometrics 2001; 57: 120–125) proposed a model-selection method for GEE...
Tipo: Article
Palavras-chave: Qic; Akaike's information criterion; GEE; Likelihood; Model; Quasilikelihood under the independence model criterion; Research Methods/ Statistical Methods.
Ano: 2007
URL: http://purl.umn.edu/119269

Mathematical Model to Compare Egg Production C
Provedor de dados: 89
Autores: Fialho,FB; Ledur,MC; Avila,VS.
A segmented polynomial model was used on several egg production curves in an attempt to analyze the differences between the curves in a more descriptive manner. Production curves from different commercial and experimental genetic lines of layers were used. The parameters of the model include the age and level of peak production, rate of decrease in production after the peak and time between start and peak of production. These and other derived variables were compared between the curves using contrasts. The methodology used allowed an easier interpretation of the curves, and the detection of differences in sexual maturity, uniformity and peak of production. This work validates the segmented polynomial model for use in future research dealing with analysis...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Egg production; Layers; Laying hens; Model.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2001000300002

Modelling energy utilization for laying type Pullets
Provedor de dados: 89
Autores: Neme,R; Sakomura,NK; Fialho,FB; Freitas,ER; Fukayama,EH.
Three trials were carried out to determine energy metabolized (EM) requirement model for starting and growing pullets from different strains, at five ambient temperatures and different percentage feather coverage. In Trial I, metabolizable energy requirements for maintenance (MEm) and efficiency of energy utilization were estimated using 64 birds of two different strains, Hy-Line W36 (HLW36) and Hy-Line Semi-heavy (HLSH), from 9 to 13 weeks of age. The effects of ambient temperature (12, 18, 24, 30 and 36ºC) and percentage feather coverage (0, 50 and 100%) on MEm were assessed in the second trial, using 48 birds per temperature per strain (HLSH and HLW36) from 9 to 13 weeks of age. Trial III evaluated ME requirements for weight gain (MEg) using 1,200 birds...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Body composition; Energy requirements; Feather coverage; Laying hens; Model; Temperature.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2005000100007

Estimation of total leaf area in perennial plants using image analysis
Provedor de dados: 91
Autores: Marcon,Marlon; Mariano,Kleber; Braga,Roberto A.; Paglis,Carlos M.; Scalco,Myriane S.; Horgan,Graham W.
One feature of most horticultural crop plants that is biologically relevant to their yield and productivity is total leaf area. However, direct methods of estimation of the leaf area cause damage to the plants, whereas indirect methods such as based on light measurement, demand accuracy in the setup of the measurement procedure, which is specific to each crop. Coffee is one of the most important perennial plants related to worldwide trade, and this demands some ability to estimate the productivity of the crop, as well as all the perennial plants involved in production of agricultural products. This study aims to build a model based on indirect measures to estimate the leaf area in coffee plants using image analysis. Two models were evaluated, one based on...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Non-destructive method; Coffee tree; Model.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662011000100014

Factors affecting beef consumption in the valley of Mexico
Provedor de dados: 96
Autores: Delgado,Ricardo Tellez; Flores,José Saturnino Mora.
ABSTRACTThe objective of this study was to know the factors that determine the consumption of beef in the Metropolitan Area of the Valley of Mexico, using logit and probit modeling (nominal variable) with 400 surveys. The results showed that significant variables that determine the probability of purchasing beef are schooling, number of members per family, meat preference, family income, and presence of disease in the individual. The largest marginal effects on the purchase decision were provided by the income and the meat preference variables, while the price was not significant. The main factors that determine the consumption of beef are schooling and the number of members in the family, while the meat preference and income are dismissed.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Consumer; Logit; Meat; Model; Probit.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982015001000371

Total leaf area of papaya trees estimated by a nondestructive method
Provedor de dados: 63
Autores: Posse,Robson Prucoli; Sousa,Elias Fernandes de; Bernardo,Salassier; Pereira,Messias Gonzaga; Gottardo,Romildo Domingos.
Leaf area estimation is an important feature in physiological research involving predominantly photosynthesis, transpiration and growth. This study was carried out to develop a practical and nondestructive empirical mathematical model to estimate the area of one leaf and the total leaf area for papaya trees (Carica papaya L.). Two irrigated commercial orchards were evaluated over a period of 50 to 550 days after transplanting, during which the length of the leaf midrib (LM) varied from 0.04 to 0.60 m. A mathematical model was developed to estimate the area of one leaf for the papaya tree, taking into account LM and the age of the plant measured in days after transplanting. The model was considered satisfactory. Based on the average length of the last two...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Carica papaya L.; Papaya; Model; Leaf architecture; Biometry.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162009000400005

Electrochemical attributes and availability of nutrients, toxic elements, and heavy metals in tropical soils
Provedor de dados: 63
Autores: Fontes,Mauricio Paulo Ferreira; Alleoni,Luís Reynaldo Ferracciú.
Electrochemical properties of soils are very important for the understanding of the physico-chemical phenomena which affect soil fertility and the availability of nutrients for plants. This review highlights the electrochemical properties of tropical soils, the behavior and the availability of nutrients, toxic elements and heavy metals in the soil, especially for soils with predominant variable charge minerals. Availability of the elements is related to ionic exchange, solution speciation, and electrostatic and specific adsorptive soil properties. Empirical and surface complexation models are briefly described, and some results of their application in tropical soils are presented. A better understanding of the role of the double diffuse layer of charges...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Electric charge; Adsorption; Model; Ionic exchange; Speciation.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000600014

Simulating the vernalization response of the "Snow Queen" lily (Lilium longiflorum Thunb.)
Provedor de dados: 63
Autores: Streck,Nereu Augusto; Schuh,Mariângela.
Vernalization is a process required by certain plant species, including lilies (Lilium spp.), to enter the reproductive phase, through an exposure to low, non-freezing temperatures. The objective of this study was to evaluate a nonlinear vernalization response function for the "Snow Queen" lily. An experiment was carried out in Santa Maria, RS, Brazil, to provide an independent data set to evaluate the performance of the model. Lily bulbs were vernalized at -0.5, 4.0, and 10ºC during two, four, six, and eight weeks. The daily vernalization rate (fvn) for each treatment was calculated with a beta function, and the effective vernalization days (VD) were calculated by accumulating fvn. The thermal time from plant emergence to visible buds at different VD...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Low temperature; Flowering; Bulb; Model; Plant development.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162005000200004

Probability density function of the number of embryos collected from superovulated Nelore breed donors
Provedor de dados: 63
Autores: Beltrame,Renato Travassos; Barioni,Luis Gustavo; Quirino,Celia Raquel; Dantas,Ozanival Dario.
Several models have been developed to evaluate reproductive status of cows through concentration of progesterone in milk, the effect of sex selection in the commercial production of herds and bioeconomic performance of the multiple ovulation and embryo transfer system in select herds. However, models describing the production of embryos in superovulated females have yet to be developed. A probability density function of the number of embryos collected by donors of the Nelore breed was determined. Records of 61,928 embryo collections from 26,767 donors from 1991 to 2005 were analyzed. Data were provided by the Brazilian Association of Creators of Zebu and Controlmax Consultoria e Sistemas Ltda. The probability density function of the number of viable...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Zebu; Cattle; Reproduction; Model.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162009000400003

ศูนย์ชัยพัฒนาการเกษตรสิรินธร ต้นแบบขยายผลศูนย์ผลิตเมล็ดพันธุ์ข้าวชุมชน จังหวัดพิจิตร
Provedor de dados: 106
Autores: Wilai Palawisut; Suratwadee Mokda; Pornsuree Kanchana; Jittichai Anawong; Chalotorn Limchareon; Rungnapa Wongsagul.
The Sirindhorn Chaipattana Agricultural Development Project is situated at Nern Makok Subdistrict, Bang Moon Nark District, Phichit Province. It was established in 2007. Phitsanulok Rice Research Center has a major responsibility for a sub-project called Quality Rice Seed Production in the area of 26 rai (9.16 ha). The main objectives are to produce a seed source and being a center of technology transfer for farmers in the area. Targets consist of producing 30 tons of foundation seed and providing a training course for 120 farmers/year. Four to five photo-insensitive rice varieties are planted 2 crops/year. Farmers learn significant steps in seed production including off-type removal, harvest, drying, cleaning, seed analysis and packing. Two hundred...
Tipo: PhysicalObject
Palavras-chave: Royal project; Seed production model; Rice seed production center; Community rice seed production center; Model; Seed source; The Sirindhorn Chaipattana Agricultural Development project; โครงการหลวง; ศูนย์ต้นแบบ; ศูนย์เมล็ดพันธุ์ข้าว; ศูนย์ผลิตเมล็ดพันธุ์ข้าวชุมชน; การผลิตเมล็ดพันธุ์; คุณภาพเมล็ดพันธุ์; เกษตรกร; แหล่งเมล็ดพันธุ์; ศูนย์ผลิตเมล็ดพันธุ์ข้าวชุมชน; จ.พิจิตร.
Ano: 2012
URL: http://anchan.lib.ku.ac.th/agnet/handle/001/5590

แบบจำลองการเจริญเติบโตและผลผลิตของถั่วเขียว โดยใช้โครงข่ายประสาทเทียม
Provedor de dados: 106
Autores: Supatsorn Kumbor; Hatsachai Boonjung; Arthit Srikaew.
Most of crop modeling is mechanistic model whereas the objective of this study was to predict mungbean growth and yield by artificial neural network (ANN). The experiment was 2 varieties (SUT1 and KPS2) x 2 water levels (rainfed and irrigation) x 3 fertilizer levels (12-24-12 rate 0, 15 and 30kg./rai) factorial experiment in RCBD 4 blocks growing for 2 seasons (no rainfed in the 2nd season). Data was collected for 10 replications in each plot. Using 560 sets of data from fertilizer rate of 0 and 30 kg/rai trained the ANN model by back propagation algorithm. The input variables were variety, fertilizer, irrigations, seasonal, growing degree day, rainfall, solar radiation and day after planting. The rest of 280 sets of data (only 15 kg/rai of fertilizer)...
Tipo: Collection
Palavras-chave: Mungbean; Artificial neural network; Model; ถั่วเขียว; โครงข่ายประสาทเทียม; แบบจำลองโครงข่ายประสาทเทียม; ผลผลิต.
Ano: 2014
URL: http://anchan.lib.ku.ac.th/agnet/handle/001/5840

Hydrotime model can describe the response of common bean (Phaseolus vulgaris L.) seeds to temperature and reduced water potential - doi: 10.4025/actascibiolsci.v35i2.15393
Provedor de dados: 3
Autores: Cardoso, Victor José Mendes; Universidade Estadual Paulista; Bianconi, André; Universidade Estadual Paulista.
Germination parameters of the response to temperature and water potential from four common bean (Phaseolus vulgaris) lines based on thermal-time and hydrotime concepts were estimated to verify to what extent they can predict germination under different thermal and water conditions. The cultivars IPR Uirapuru and IAPAR 81 (drought-tolerant), and Grauna and Carioca (not tolerant) were used. The isothermal assays were performed in a temperature gradient block, and the assays with different osmotic potentials (PEG 6000) were performed in germination chambers. Seeds from drought-tolerant cultivars spent less time to germinate at supra-optimum temperatures than non-tolerant ones, and the cultivar Uirapuru (drought-tolerant) germinated faster in response to...
Palavras-chave: Carioca; Grauna; IAPAR 81; Uirapuru; Germination; Model.
Ano: 2013
URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/15393

DEVELOPMENT OF A MODEL TO DETERMINE THE SHELF LIFE OF YELLOW VARIETY OF CASHEW FRUIT JUICE AT NON REFRIGERATED STORAGE
Provedor de dados: 111
Autores: chikwado, ugwu kenneth.
ABSTRACTThere is an inevitable decline in quality value of ascorbic acid in storage and distribution of cashew apple juice. The quality value and maximum shelf life of yellow sample of cashew apple juice were estimated and the quality value model based on the deteriorative factors was developed.  It was discovered that balancing these factors led to satisfactory quality control of ascorbic acid degradation in cashew fruit juice during non refrigeration storage conditions and the distribution.  Data were drawn from 34 full factorial experiments conducted in three replicates with the order of the replicates randomized. A multivariate regression analysis was used for relating the variables. The results of the experiment and the model developed for yellow...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Development; Model; Shelf Life; Yellow Cashew Fruit Juice; Refrigerated Storage.
Ano: 2022
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/6325

Assessment of the CERES-Rice model for rice production in Ibadan, Nigeria
Provedor de dados: 111
Autores: Christopher Oluwakunmi Akinbile; FUTA.
CERES-Rice model was used to simulate growth and yield of a new rice variety in Nigeria with the attention on rates of water application, one major factor that retards crop’s grain yield. The rates were full irrigation (100%ET), medium (75% ET), average (50% ET) and low (25% ET) irrigation intervals. The NEw RIce for AfriCA (acronym for NERICA) 2 variety was grown at the International Institute for Tropical Agriculture (IITA), Ibadan, Nigeria. Experimental agronomic values of parameters such as plant height, root depth, canopy shading, Leaf area index (LAI), biomass and grain yield in relation to water use were obtained and compared with simulated modelled values from CERES and the results were subjected to statistical analysis. The model predicted...
Palavras-chave: Agricultural Engineering; Soil and Water Conservation Engineering Rice; Model; Water; Simulation; Production; Food security.
Ano: 2013
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/2405

Mathematical modeling of mechanical horizontal screw oil extractor
Provedor de dados: 111
Autores: BAKO, TANKO; ENYI, OBETTA SAMUEL; IMOLEMHE, UMOGBAI VICTOR.
A theory using mechanical expression was proposed from the physics of oil expression in a screw press to characterize a mathematical model. The general oil expression equation was solved for three machine parameters (choke clearances, screw shaft clearances and screw shaft speeds) which simulate the machine parameters effects in the overall screw expeller process. The mathematical model was validated by the experimental data obtained from pressing fish oil with a screw press, using regression analysis. The experimental oil extraction data was fitted to the model and the quality of fit evaluated. A good fit was indicated by correlation coefficient of 0.9983, coefficient of determination of 0.9967, absolute average percentage deviation of 4.8 %, coefficient...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mathematical; Model; Extraction; Parameters.
Ano: 2020
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/5521

Batch anaerobic digestion of banana waste - energy potential and modelling of methane production kinetics
Provedor de dados: 111
Autores: Khan, Muhammad Tahir; Brulé, Mathieu; Maurer, Claudia; Argyropoulos, Dimitrios; Müller, Joachim; Oechsner, Hans.
Different fractions of banana (stalk, peel, and flesh) as well as the whole unpeeled banana were studied in a laboratory Biochemical Methane Potential (BMP) assay. After completion of 35-day digestion at 37°C in 2L-reactors, specific methane yields reached 0.256, 0.322, 0.367 and 0.349 m³/kg VS (volatile solids) for stalk, peel, flesh, and unpeeled banana respectively. Considering the country of Uganda, East Africa, the collection of peels and stalks from banana production would yield a theoretical potential of about 60 GWh of electrical energy per year in biogas plants. In order to verify the suitability of banana fractions to the biogas process, their chemical composition was analyzed, and their methane production kinetics was estimated with exponential...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Energy biogas; Anaerobic digestion; BMP assay; Model; Energy; Methane; Waste.
Ano: 2016
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3244

Model evaluation of quality attributes for hops (Humulus lupulus L.)
Provedor de dados: 115
Autores: Pavlovic,Martin; Pavlovic,Viljem.
Hops (Humulus lupulus L.) ate vital fot the brewing industry, as they contribute significantly to the organoleptic qualities of beet, including taste and flavor. Experimental hop breeding data from the Slovenian Institute of Hop Research and Brewing (IHPS) were used to create a model based on the multi-attribute decision modeling methodology. The model has 18 attributes hierarchically grouped within four main attributes: Biology, Chemistry, Morphology and Brewing value. Furthermore, utility functions in the model were defined by sets of elementary decision rules throughout the entire hierarchy for all aggregated attributes. The central part of the model contains 144 decision rules, which were specified according to the model users' previous breeding...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hop industry; Breeding; Decision-making; Model; IHPS.
Ano: 2011
URL: http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1405-31952011000300007

Novel model of calcium and inositol 1,4,5-trisphosphate regulation of InsP3 receptor channel gating in native endoplasmic reticulum
Provedor de dados: 48
Autores: Foskett,J. Kevin; Mak,D.-O. Daniel.
The InsP3R Ca2+-release channel has biphasic dependence on cytoplasmic free Ca2+ concentration ([Ca2+]i). InsP3 activates gating primarily by reducing high [Ca2+]i inhibition. To determine whether relieving Ca2+ inhibition is sufficient for activation, we examined single-channels in low [Ca2+]i in the absence of InsP3 by patch clamping isolated Xenopus oocyte nuclei. For both endogenous Xenopus type 1 and recombinant rat type 3 InsP3R channels, spontaneous InsP3-independent activities with low open probability Po (~ 0.03) were observed in [Ca2+]i &lt; 5 nM, whereas none were observed in 25 nM Ca2+. These results establish the half-maximal inhibitory [Ca2+]i in the absence of InsP3 and demonstrate that the channel can be active when all of its...
Tipo: Journal article
Palavras-chave: InsP3 receptor; Calcium release channel; Calcium; Ion channel; Model.
Ano: 2004
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000400004

Modeling the pressure inactivation dynamics of Escherichia coli
Provedor de dados: 56
Autores: Yamamoto,K.; Matsubara,M.; Kawasaki,S.; Bari,M.L.; Kawamoto,S.
Escherichia coli, as a model microorganism, was treated in phosphate-buffered saline under high hydrostatic pressure between 100 and 300 MPa, and the inactivation dynamics was investigated from the viewpoint of predictive microbiology. Inactivation data were curve fitted by typical predictive models: logistic, Gompertz and Weibull functions. Weibull function described the inactivation curve the best. Two parameters of Weibull function were calculated for each holding pressure and their dependence on holding pressure was obtained by interpolation. With the interpolated parameters, inactivation curves were simulated and compared with the experimental data sets.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Predictive microbiology; Pressure; Escherichia coli; Inactivation; Model.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000800014

Standardization of an isolated pig heart preparation with parabiotic circulation: methodological considerations
Provedor de dados: 56
Autores: Petrucci Júnior,O.; Oliveira,P.P.M.; Carmo,M.R.; Vieira,R.W.; Braile,D.M.
In the present study we standardized an experimental model of parabiotic circulation of isolated pig heart. The isolated heart was perfused with arterial blood from a second animal as support and submitted to regional ischemia for 30 min, followed by total ischemia for 90 min and reperfusion for 90 min. Parameters for measurement of ventricular performance using different indices measured directly or indirectly from intraventricular pressure were defined as: maximum peak pressure, final diastolic pressure, pressure developed, first derivative of maximum pressure (dP/dt max), first derivative of minimum pressure (dP/dt min), systolic stress of the left ventricle (sigmas), and maximum elastance of the left ventricle. Isolated hearts subjected to regional and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Isolated heart; Ischemia; Parabiotic circulation; Reperfusion; Model.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000500013

Leishmania (Leishmania) chagasi-infected mice as a model for the study of glomerular lesions in visceral leishmaniasis
Provedor de dados: 56
Autores: Prianti,M.G.; Yokoo,M.; Saldanha,L.C.B.; Costa,F.A.L.; Goto,H.
Renal involvement in visceral leishmaniasis (VL) is very frequent but the pathogenesis of this nephropathy is poorly understood. In previous studies using dogs with VL we have detected new immunopathological elements in the glomeruli such as T cells and adhesion molecules. Although Leishmania (Leishmania) chagasi-infected dogs and hamsters are considered to be good models for VL, their use is limited for immunopathologic studies. The use of isogenic mouse strains susceptible to L. (L.) chagasi infection was an alternative but, on the other hand, the renal lesions of these animals have not yet been characterized. Thus, our purpose in the present study was to characterize mice infected with L. (L.) chagasi as a suitable model to study VL nephropathy. Kidney...
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Visceral leishmaniasis; Glomerulonephritis; Mice; Model; Leishmania (Leishmania) chagasi.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2007000600011

Apoplasm hydrostatic pressure on growth of cylindrical cells
Provedor de dados: 61
Autores: Pessoa,José Dalton Cruz; Calbo,Adonai Gimenes.
According to the model frequently used as reference, plant cell growth occurs only when turgor surpasses a threshold. This model was proposed considering a cylindrical cell of constant wall thickness immerged in a water solution, with viscoelastic behaviour, hydraulic conductivity, variable extensibility, and unidirectional elongation. The author, Lockhart (1965), did not consider the effects of apoplasm hydrostatic potential, a subject treated later by Calbo and Pessoa (1994) who argued that this component of cell potential would interfere with cell growth rate. To evaluate this effect, where possible the same deductive procedures as those employed by Lockhart were used here, which resulted in a set of equivalent equations for cell growth, turgor and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Apoplasm; Cell wall; Growth; Lockhart; Model; Plant.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202004000100003

Evaluation of the Water Requirements for a Greenhouse Tomato Crop using the Priestley-Taylor Method
Provedor de dados: 117
Autores: Valdés-Gómez,Héctor; Ortega-Farías,Samuel; Argote,Mauricio.
The Priestley-Taylor (PT) model was evaluated for estimating the real evapotranspiration (ETreal) of a drip-irrigated greenhouse tomato (Lycopersicon esculentum Mill.) crop. The net radiation incorporated in the PT model was estimated using meteorological variables. For this experiment, an automatic weather station (AWS) was installed inside the greenhouse to measure solar radiation (Rgi), net radiation (Rn), air temperature (Ta) and relative humidity (RH). Another AWS was installed over a grass cover to measure atmospheric conditions outside the greenhouse. The experiment was carried out at the Panguilemo experimental station (35°23' S, 71°40' W, 110 m.a.s.l.) from August to December 2000. The PT model was evaluated using the ETreal obtained from the...
Tipo: Journal article
Palavras-chave: Irrigation; Model; Crop coefficients; Net radiation; Soil heat flu.
Ano: 2009
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392009000100001

Furrow Irrigation Management and Design Criteria Using Efficiency Parameters and Simulation Models
Provedor de dados: 117
Autores: Holzapfel,Eduardo A.; Leiva,Carlos; Mariño,Miguel A.; Paredes,Jerónimo; Arumí,José L.; Billib,Max.
This study analyzes the relationship between the variables of furrow irrigation and the irrigation performance parameters, crop yield, and deep percolation as a basis for furrow irrigation design and management. Application efficiency (AE), requirement efficiency (RE), requirement distribution efficiency (RDE), total distribution efficiency (TDE), and furrow irrigation management, operation, and design variables (inflow discharge, furrow length, and irrigation cutoff time) were correlated. The relationship between performance irrigation parameters and relative yield was also examined. In addition, environmental aspects related to leaching and runoff were also presented for each of the parameters. Study results indicate that increasing the length of the...
Tipo: Journal article
Palavras-chave: Furrow; Irrigation; Performance parameters; Model; Yield; Leaching.
Ano: 2010
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392010000200012

Estimation of leaf area in pecan cultivars (Carya illinoinensis)
Provedor de dados: 118
Autores: Torri,Silvana Irene; Descalzi,Carla; Frusso,Enrique.
S.L Torri , C. Descalzi, and E. Frusso. 2009. Estimation of leaf area in pecan cultivars (Carya illinoinensis). Cien. Inv. Agr. 36(1): 53-58. Nondestructive and mathematical approaches of modeling can be very convenient and useful for plant growth estimation. The objective of this research was to develop a simple, accurate and nondestructive predictive model for leaf area (LA) estimation in different pecan cultivars (Carya illinoinensis) commonly found in Argentina. Linear and exponential regression equations were fitted and evaluated for pecan cultivars 'Desirable', 'Harry Super', 'Kernodle', 'Mahan', 'Mahan-Stuart', 'Shoshoni', 'Stuart' and 'Success' (grafted on seedling pecan rootstocks, 24 years old, planted at 15 x 15 m) using length (L) and width (W)...
Tipo: Journal article
Palavras-chave: Carya illinoinensis; Leaf area; Leaf length; Leaf width; Model; Pecan.
Ano: 2009
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202009000100004

Analysis of soil organic matter in tropical soils with near-infrared spectroscopy (NIRS) and chemometrics
Provedor de dados: 118
Autores: Jarquín-Sánchez,Aarón; Salgado-García,Sergio; Palma-López,David J; Camacho-Chiu,Wilder.
The objective of this study was to predict the concentration of soil organic matter (SOM) in tropical soils using near-infrared spectroscopy (NIRS) for samples measured within a polyethylene bag and without a bag. One hundred and fifty six soil samples from the humid tropics of Tabasco, Mexico with contrasting chemical characteristics were selected. The samples were dried, ground, and sieved through 2 mm and 5 mm screens, and their SOM contents were determined using the Walkley-Black method. The soil samples were packed in polyethylene bags, and SOM was measured directly with and without a bag using a quartz probe (FOSS 5000 model of NIRsystems, DK-3400 Hillerod,Denmark) for a range from 1100 to 2000 nm to obtain a prediction model of SOM. The model for...
Tipo: Journal article
Palavras-chave: Chemical analysis; Tropical soil; Optical fiber; Model; Organic matter prediction.
Ano: 2012
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202012000200015

Estimation of herbicide bioconcentration in sugarcane (Saccharum officinarum L.)
Provedor de dados: 65
Autores: Cerdeira,Antonio Luiz; Paraíba,Lourival Costa; Queiroz,Sonia Claudia Nascimento de; Matallo,Marcus Barifouse; Franco,Daniel Andrade de siqueira; Ferracini,Vera Lúcia.
Sugarcane is an important crop for sugar and biofuel production in Brazil. Growers depend greatly on herbicides to produce it. This experiment used herbicide physical-chemical and sugarcane plant physiological properties to simulate herbicide uptake and estimate the bioconcentration factor (BCF). The (BCF) was calculated for the steady state chemical equilibrium between the plant herbicide concentration and soil solution. Plant-water partition coefficient (sugarcane bagasse-water partition coefficient), herbicide dilution rate, metabolism and dissipation in the soil-plant system, as well as total plant biomass factors were used. In addition, we added Tebuthiuron at rate of 5.0kg a.i. ha-1 to physically test the model. In conclusion, the model showed the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Herbicide; Bioconcentration factor; Plant uptake; Model; Bagasse adsorption.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782015000400591

Dendrometric evaluation of a clonal population of Tectona grandis in forest-livestock system
Provedor de dados: 65
Autores: Maria,Luciano de Souza; Litter,Felipe Adolfo; Carneiro,Márcia de Almeida; Silva,Fabrícia Rodrigues da; Garcia,Marcos Leandro; Carvalho,Marco Antonio Camillo de.
ABSTRACT:  Production of Tectona grandis (teak) in integrated systems with livestock or agriculture demonstrates high potential of financial return. However, studies on the development of teak are still scarce, especially in the northern region state of Mato Grosso. In this study we sought to evaluate dendometric variables of a clonal population of teak in a forest-livestock integration system (LFIS), during a period of 53 months in the city of Alta Floresta, Mato Grosso, Brazil. For this purpose, three installments were samples, a total of 360 individuals, and for each the diameter was measured at 1.3 meters from the base so as to calculate the total volume, the current annual increment (CAI) and mean annual increment (MAI), and five adjusted regression...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Growth; Model; LFIS; Teak.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019000900301

A generalized nonlinear tempeature response function for some growth and developmental parameters in kiwifruit (Actinidia deliciosa (A. Chev.) C. F. Liang &amp;amp; A. R. Ferguson)
Provedor de dados: 65
Autores: Streck,Nereu Augusto.
Temperature is a major factor that affects metabolic processes in living organisms. Thermal time has been widely used to account for the effects of temperature on crop growth and development. However, the thermal time approach has been criticized because it assumes a linear relationship between the rate of crop growth or development and temperature. The response of the rate of crop growth and development to temperature is nonlinear. The objective of this study was to develop a generalized nonlinear temperature response function for some growth and developmental parameters in kiwifruit (Actinidia deliciosa (A. Chev.) C. F. Liang &amp;amp; A. R. Ferguson). The nonlinear function has three coefficients (the cardinal temperatures), which were 0ºC, 25ºC, and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Temperature; Model; Growth; Development; Kiwifruit.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782003000200012

A temperature response function for development of the chrysanthemum (Chrysanthemum x morifolium Ramat.)
Provedor de dados: 65
Autores: Streck,Nereu Augusto.
Developmental models can help growers to decide management practices, and to predict flowering and harvest time. Currently, a double exponential function is proposed as a generalized temperature response function for chrysanthemum. This function is not the most appropriate because its parameters lack biological meaning. The objective of this study was to develop a nonlinear temperature response function of chrysanthemum development that has parameters with biological meaning. The proposed function is a beta function with three parameters, the cardinal temperatures (minimum, optimum, and maximum temperatures for development), which were defined as 0, 22, and 35ºC. Published data of temperature response of development of three cultivars, which are...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Phenology; Flowering; Model.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782004000100008

Observed and estimated leaf appearance of landrace and improved maize cultivars
Provedor de dados: 65
Autores: Langner,Josana Andreia; Streck,Nereu Augusto; Durigon,Angelica; Silva,Stefanía Dalmolin da; Lago,Isabel; Dalmago,Genei Antonio; Reiniger,Lia Rejane Silveira; Scheffel,Lúcio Gabriel; Poersch,Anderson Haas.
ABSTRACT: The objective of this study was to compare the simulations of leaf appearance of landrace and improved maize cultivars using the CSM-CERES-Maize (linear) and the Wang and Engel models (nonlinear). The coefficients of the models were calibrated using a data set of total leaf number collected in the 11/04/2013 sowing date for the landrace varieties ‘Cinquentinha’ and ‘Bico de Ouro’ and the simple hybrid ‘AS 1573PRO’. For the ‘BRS Planalto’ variety, model coefficients were estimated with data from 12/13/2014 sowing date. Evaluation of the models was with independent data sets collected during the growing seasons of 2013/2014 (Experiment 1) and 2014/2015 (Experiment 2) in Santa Maria, RS, Brazil. Total number of leaves for both landrace and improved...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Zea mays L.; Vegetative development; Air temperature; Sowing time; Model.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782018000100201

A temperature response function for modeling leaf growth and development of the African violet (Saintpaulia ionantha Wendl.)
Provedor de dados: 65
Autores: Streck,Nereu Augusto.
Response functions used in crop simulation models are usually different for different physiological processes and cultivars, resulting in many unknown coefficients in the response functions. This is the case of African violet (Saintpaulia ionantha Wendl.), where a generalized temperature response for leaf growth and development has not been developed yet. The objective of this study was to develop a generalized nonlinear temperature response function for leaf appearance rate and leaf elongation rate in African violet. The nonlinear function has three coefficients, which are the cardinal temperatures (minimum, optimum, and maximum temperatures). These coefficients were defined as 10, 24, and 33ºC, based on the cardinal temperatures of other tropical...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Temperature; Model; Leaf growth; Leaf development; African violet.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782004000100009