Consulta: subjectFacets:"Stratification"
Registros recuperados: 35
Data/hora: 12/06/2024 02:33:30

Capacidad germinativa de semillas de Taxus globosa Schltdl.
Provedor de dados: 32
Autores: Ramírez Sánchez, Susana Elizabeth.
Taxus globosa Schtdlt. es una especie de importancia no solo por encontrarse en la NOM-059-ECOL-2010, sino, también por que produce un metabolito llamado taxol que es utilizado comercialmente para contrarrestar el cáncer. Actualmente, su obtención de esta especie es complicada, pues por encontrarse dentro de la norma, está prohibida su extracción; además su distribución en México es discontinua y su semilla presenta latencia, condición que dificulta mucho la propagación por medio de semilla; la germinación es escalonada y baja (2 al 14%). Es la única especie de este género en México y se considera endémica de nuestro país y de América central. Por lo que, en la presente investigación se buscó evaluar las diferencias morfológicas en las semillas de dos...
Palavras-chave: Taxus globosa; Germinación; Tratamientos pre-germinativos; Incubación; Estratificación; Germination; Pre-germination treatments; Incubation; Stratification; Producción de Semillas; Doctorado.
Ano: 2012
URL: http://hdl.handle.net/10521/1089

Многолетняя сезонная динамика распределения бактериопланктона в северо-западной части Черного моря
Provedor de dados: 13
Autores: Шумакова, Г. В.
Представлены результаты анализа многолетних данных по распределению общей численности бактериопланктона в северо-западной части Черного моря в период с 1971 по 1997 гг. Более высокая плотность бактериального населения  приурочена к приустьевым районам, из которых летом  выделяется Дунайский (4,43   х 106 клеток/мл), а весной и осенью  - Днепровско-Бугский  (3,58 – 4,17 х 106 клеток/мл).  Накопление бактериальной биомассы в приустьевых районах было обусловлено обилием речного стока и хорошо выраженной вертикальной стратификацией вод. В тёплые месяцы бактериопланктон  концентрировался в верхнем перемешанном слое, как  в открытой части моря, так   и  в приустьевых районах. Приводятся карты пространственного распределения бактериопланктона на поверхности в...
Tipo: Journal Contribution
Palavras-chave: Stratification; Stratification; Http://aims.fao.org/aos/agrovoc/c_7438.
Ano: 2002
URL: http://repository.ibss.org.ua/dspace/handle/99011/412

Coherent heat patterns revealed by unsupervised classification of Argo temperature profiles in the North Atlantic Ocean
Provedor de dados: 5
Autores: Maze, Guillaume; Mercier, Herle; Fablet, Ronan; Tandeo, Pierre; Radcenco, Manuel Lopez; Lenca, Philippe; Feucher, Charlene; Le Goff, Clement.
A quantitative understanding of the integrated ocean heat content depends on our ability to determine how heat is distributed in the ocean and what are the associated coherent patterns. This study demonstrates how this can be achieved using unsupervised classification of Argo temperature profiles. The classification method used is a Gaussian Mixture Model (GMM) that decomposes the Probability Density Function of a dataset into a weighted sum of Gaussian modes. It is determined that the North Atlantic Argo dataset of temperature profiles con- tains 8 groups of vertically coherent heat patterns, or classes. Each of the temperature profile classes reveals unique and physically coherent heat distributions along the vertical axis. A key result of this study is...
Tipo: Text
Palavras-chave: Heat content; Classification North Atlantic; Stratification; Water mass; Thermocline; Argo; Pattern.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00363/47431/47456.pdf

Observations on the Lateral Structure of Wind-Driven Flows in a Stratified, Semiarid Bay of the Gulf of California
Provedor de dados: 5
Autores: Winant, Chloe; Valle-levinson, Arnoldo; Ponte, Aurelien; Winant, Clinton; Gutierrez-de-velasco, Guillermo; Winters, Kraig.
Time series of current velocity profiles and thermistor chains were obtained throughout a cross-bay transect for ~90 days for the purpose of comparing observed wind-driven stratified flows to theory. This study concentrates on the synoptic scale wind and its influence on the bay’s circulation. The maximum water column stratification was 3–4 °C/m throughout the deployment and influenced wind-driven flows. Low-pass filtered flows showed more complicated structures than those expected from theory: a depth-dependent recirculating structure with the along-bay flow over one half of the transect moving in opposite direction to the other half. Analysis of complex empirical orthogonal functions indicated that the first six modes explained 80 % of the flow...
Tipo: Text
Palavras-chave: Wind-driven flow; Stratification; Concepcion Bay; Semiarid.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00171/28218/32176.pdf

Southwest Pacific Ocean response to a warming world: Using Mg/Ca, Zn/Ca, and Mn/Ca in foraminifera to track surface ocean water masses during the last deglaciation
Provedor de dados: 5
Autores: Marr, Julene P.; Carter, Lionel; Bostock, Helen C.; Bolton, Annette; Smith, Euan.
In situ measurements of Mg/Ca, Zn/Ca, Mn/Ca, and Ba/Ca in Globigerinoides bulloides and Globigerina ruber from southwest Pacific core top sites and plankton tow are reported and their potential as paleoproxies is explored. The modern samples cover 20 degrees of latitude from 34 degrees S to 54 degrees S, 7-19 degrees C water temperature, and variable influence of subantarctic (SAW) and subtropical (STW) surface waters. Trace element signatures recorded in core top and plankton tow planktic foraminifera are examined in the context of the chemistry and nutrient profiles of their modern water masses. Our observations suggest that Zn/Ca and Mn/Ca may have the potential to trace SAW and STW. Intraspecies and interspecies offsets identified by in situ...
Tipo: Text
Palavras-chave: Mg; Ca; Mn; Ca; Ba; Ca; Zn; Ca; Southwest Pacific Ocean; Globigerina bulloides; Globigerinoides ruber; Surface ocean; Stratification; Temperature; Nutrient.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00264/37528/35765.pdf

Impact du régime du barrage d'Arzal sur la stratification a l'embouchure de la Vilaine : étude par modélisation numérique
Provedor de dados: 5
Autores: Le Hir, Pierre; Duchene, C.; Merel, A; De Nadaillac, G.; Merceron, Michel; Breton, Marguerite.
The rate of flow of the fresh water releases at the Arzal Dam into the Vilaine is likely to influence the haline structure of Vilaine Bay. In order to determine the rate of flow that causes a minimum downstream stratification, a vertical two-dimensional mathematical modelling of the Vilaine's estuary was undertaken. We obtain very similar stratification flows for different fresh water release scenarios, in spite of the rather different desalinisations and currents.
Tipo: Text
Palavras-chave: Water release; Stratification; Estuary; Numerical model; Vilaine; Rejet de barrage; Stratification; Estuaire; Modèle numérique; Vilaine.
Ano: 1986
URL: https://archimer.ifremer.fr/doc/1986/rapport-2654.pdf

Stock assesments of the non-cultivated molluscs in the oyster culture area of Marennes Oleron
Provedor de dados: 5
Autores: Sauriau, Pierre-guy.
A quantitative sampling was made on the non-cultivated molluscs of the soft bottom macrofauna in the bay of Marennes-Oleron. A stratified random sampling, including an optimal allocation strategy. provided adequate data to estimate abundance and biomass (total weight. dry weight and ash-free-dry weight) of each molluscan species. The main stratification factors were respectively the bathymetric levels. the different types of sediment and the differences between natural, oyster-free mud flats and cultivated areas. A Smith Mc-Intyre grab was used to sample the subtidal, shallow areas and the tidal flats as well. The total number of sampling stations was 370. The final estimation of the total weight of benthic molluscs was 14,400  ± 3,000 tons (at 95 %...
Tipo: Text
Palavras-chave: Marennes Oleron; Non cultivated benthic molluscs; Biomass; Stock assessments; Stratrification; Sampling; Marennes Oléron; Molluques benthiques non cultivés; Biomasse; Stocks; Stratification; Echantillonnage.
Ano: 1987
URL: http://archimer.ifremer.fr/doc/1987/publication-2867.pdf

Coccolith-derived turbidity and hydrological conditions in May in the Bay of Biscay
Provedor de dados: 5
Autores: Perrot, Laurie; Gohin, Francis; Ruiz-pino, Diana; Lampert, Luis; Huret, Martin; Dessier, Aurelie; Malestroit, Pascale; Dupuy, Christine; Bourriau, Paul.
Coccolithophore blooms occur regularly from April to June in the Bay of Biscay where they have been observed for many years from ocean-colour imagery thanks to the ability of their calcite plates to scatter light. They are easily depicted on interpolated images of non-algal Suspended Particulate Matter (SPM) derived from satellite reflectance data in May, at the time of the PELGAS (PELagique GAScogne) annual surveys. Over the springs 2012 to 2015, the PELGAS surveys provided in-situ data on the turbidity throughout the water column and on the hydrological environment prevailing during the blooms in the vicinity of the continental shelf break. The satellite-derived SPM in the area of coccolithophore blooms was closely related to measured turbidity in the...
Tipo: Text
Palavras-chave: Bay of Biscay; Ocean colour; Suspended particulate matter; Turbidity; Coccoliths; Stratification.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00416/52790/53689.pdf

Hydrodynamics and SPM transport in a man-engineered tidal estuary: The Adour river (France)
Provedor de dados: 5
Autores: Defontaine, Sophie; Sous, Damien; Morichon, Denis; Verney, Romaric; Monperrus, Mathilde.
The present paper reports on a series of field experiments aiming to characterise the functioning of a man-engineered strongly forced salt-wedge estuary: the lower estuary of the Adour river, France. Bottom-moored velocity measurements and surface boat surveys have been performed under low river discharge conditions, for both neap and spring tides, in order to provide a well-documented reference framework to understand the dynamics of water masses, turbulence and suspended particulate matter (SPM) transport in the lower estuary. An additional campaign has been carried out in high river discharge conditions. This first documented in-situ study of the Adour lower estuary demonstrates its variability in terms of hydrological regimes, from salt-wedge to...
Tipo: Text
Palavras-chave: Salt-wedge estuary; Estuarine circulation; Stratification; Turbulence; Suspended particles transport; Adour river.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00588/70049/67987.pdf

The influence of quasi resonant internal waves on the radar imaging mechanism of shallow sea bottom topography
Provedor de dados: 5
Autores: Hennings, I; Metzner, M; De Loor, Gp.
During previous field experiments in the North Sea it was often assumed that the water column in such shallow coastal tidal waters is vertically well mixed and stratification was neglected when discussing the Normalized Radar Cross Section modulation caused by the sea floor. In this paper the influence of quasi resonant internal waves with the sea bed on the radar imaging mechanism of submarine sand waves itself is investigated. In situ data of the tidal cur-rent velocity and several water quality parameters such as sea surface temperature, fluorescence. and beam transmittance were measured in the Southern Bight of the North Sea in April 1991. Simulations of the total NRCS modulation caused by sand waves and internal waves as a function of the current...
Tipo: Text
Palavras-chave: Mécanisme des images radar; Topographie des fond marins; Stratification; Ondes internes; Radar imaging mechanism; Sea bottom topography; Stratification internal wave; Strain rate.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/00322/43322/42932.pdf

Subtropical Mode Waters and Permanent Pycnocline properties in the World Ocean
Provedor de dados: 5
Autores: Feucher, Charlene; Maze, Guillaume; Mercier, Herle.
A global reference state of the subtropical mode waters and permanent pycnoclines properties for the 2000‐2015 period is presented. The climatology is obtained from a pattern recognition algorithm applied to stratification profiles from the Argo global array. The stratification features are identified as permanent upper ocean pycnostad and pycnocline even when the seasonal pycnocline is developed. The climatology shows that both Northern Hemisphere subtropical gyres have a qualitatively very similar stratification structure. The permanent pycnocline in the North Atlantic and North Pacific show two deep centers colocated with thick subtropical and subpolar mode waters. These centers coincide with modes in the density and stratification space. These deep...
Tipo: Text
Palavras-chave: Subtropical gyre; Pycnocline; Argo; Global ocean; Stratification.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00480/59176/61817.pdf

Detecting sampling outliers and sampling heterogeneity when catch-at-length is estimated using the ratio estimator
Provedor de dados: 5
Autores: Vigneau, Joel; Mahevas, Stephanie.
Measuring fish on board fishing vessels or at fish markets to collect data for stock assessment purposes is one of the most straightforward actions carried out by fisheries scientists worldwide. However, such samples are not straightforward to handle and analyse because of their vector-type structure. A generic tool that allows investigation in any multinomial-like sampling scheme is provided, as long as the scheme is built on a ratio estimator, which is the case for most length sampling in the fisheries sector. The use of this tool is discussed using data obtained from two different sampling designs, one consisting of commercial market samples by category and the other on fishing activity or metier. The identification of outliers, misallocated samples, or...
Tipo: Text
Palavras-chave: Stratification; Sampling design; Market sampling; Length structure.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2731.pdf

Role des bacteries phototrophes anoxygeniques dans une partie stratifiee d'une lagune tropicale (Lagune Ebrie, Cote d'Ivoire)
Provedor de dados: 5
Autores: Caumette, P.
In the deepest parts of the estuarine region of Ebrie Lagoon (Abidjan Africa, (5 degree N, 4 degree W) stratified conditions have been observed during the rainy season (May to Nov.), owing to salinity differences between oxic and anoxic layers. At the interface, 3-4 m depth, phototrophic bacteria (Chromatium, Chlorobium and Pelodictyon ) developed, forming a brown layer due to their different pigments. Their production has been estimated at 41% of the total photosynthetic production during high stratification (Sep. 1981) and their biomass was used by the copepod population for 40 to 60% of its diet. During the dry season, the water column became homogeneous and oxygen was detected to 6m depth. The brown layer of phototrophic bacteria disappeared, as well...
Tipo: Text
Palavras-chave: Chlorobium; Chromatium; Primary production; Photosynthesis; Estuaries; Seasonal variations; Plankton; Stratification; Vertical distribution; Bacteria; Coastal lagoons; Trophic relationships; Biomass.
Ano: 1984
URL: http://archimer.ifremer.fr/doc/1984/acte-957.pdf

Two- or three-layered box-models versus fine 3D models for coastal ecological modelling? A comparative study in the English Channel (Western Europe)
Provedor de dados: 5
Autores: Menesguen, Alain; Cugier, Philippe; Loyer, Sophie; Vanhoutte Brunier, Alice; Hoch, Thierry; Guillaud, Jean-francois; Gohin, Francis.
The general trend in ecosystem modelling is to improve the spatial resolution by shifting from rough box-models to fine 3D models. Despite the continuous speeding-up of computing, 3D models involving numerous state variables may remain intractable, especially for parameter calibration, when processes with long half-life periods (i.e, from years to decades) are introduced, such as the behaviour of organic matter in sediment and population dynamics of benthic species. In these cases, a first approach can be provided by fast-running box-models, if they take into account the most crucial hydrodynamic properties of the system. In a macrotidal shelf sea such as the English Channel, the long-term horizontal transport can be summarized by the tidal residual...
Tipo: Text
Palavras-chave: English Channel; Stratification; Diatom/dinoflagellate succession; 3D model; Layered box model.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2315.pdf

A new statistic for sampling design investigation : an application to length-structured landings sampling
Provedor de dados: 5
Autores: Vigneau, Joel; Mahevas, Stephanie.
Measuring fish on a market or on board a vessel is the most common action taken by biologists all around the world to gather data for stock assessment. The samples coming from this kind of survey are of vector type and are not straightforward to analyse and compare. This paper proposes a generic tool that enables to investigate in any multinomial like sampling scheme. The use of this tool will be discussed based on examples from two different sampling designs. One is a sampling of commercial market categories and the other is a métier based sampling. The research of outliers, misallocated samples or potential bias, the stratification and the analysis of within and between strata variance will be discussed with the objective of constructing the best...
Tipo: Text
Palavras-chave: Stratification; Sampling design; Length structure; Market sampling.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/acte-2698.pdf

Postglacial paleoceanography of the western Barents Sea: Implications for alkenone-based sea surface temperatures and primary productivity
Provedor de dados: 5
Autores: Łącka, Magdalena; Cao, Min; Rosell-melé, Antoni; Pawłowska, Joanna; Kucharska, Małgorzata; Forwick, Matthias; Zajączkowski, Marek.
The increasing influence of Atlantic Water (AW) in the Barents Sea, a process known as “Atlantification”, is gradually decreasing sea ice cover in the region. Ongoing global climate warming is likely to be one of its drivers, but to further understand the role of natural variability and the biogeochemical impacts of the inflow of AW into the western Barents Sea, we reconstructed sea surface temperatures (SSTs) and primary productivity in Storfjordrenna, a climatically sensitive area south of Spitsbergen, between approximately 13,950 cal yr BP and 1300 cal yr BP. The alkenone proxy has been applied to reconstruct SSTs, and the alkenone accumulation rate in marine sediments has been used to infer changes in primary productivity. Our data show that the SST...
Tipo: Text
Palavras-chave: Alkenones; Stratification; Holocene; Sea ice decrease; Global warming; North Atlantic Current; Arctic.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00585/69740/67629.pdf

Mortalites de poissons en baie de Vilaine (Juillet 1982) Causes - Mécanismes - Propositions d'action
Provedor de dados: 5
Autores: Merceron, Michel.
The massive number of fish mortalities that occurred in July of 1982 in Vilaine Bay is due to a very pronounced oxygen depletion in the bay's bottom waters. This loss was caused by the chronic fragility of this area, associated with an abnormal weather pattern. The endemism of partial oxygen depletion has been brought to light. The latter could be economically more significant than the anoxia of 1982. Preventative and warning actions have been proposed.
Tipo: Text
Palavras-chave: Brittany; Dam; Estuary; Meteorological factors; Stratification; Phytoplankton; Oxygen depletion; Coastal waters; Fish kill; Estuaire; Facteurs météorologiques; Stratification; Prolifération planctonique; Déficit en oxygène; Eaux côtières; Mortalité de poisson.
Ano: 1987
URL: http://archimer.ifremer.fr/doc/1987/rapport-2836.pdf

Ocean Salinity Stratification (OSS)
Provedor de dados: 5
Autores: Maes, Christophe; O'Kane, Terence.
This dataset is composed by the climatological seasonal field of the Ocean Salinity Stratification as defined from the Brunt-Vaisala frequency limited to the upper 300 m depth. The details are given in Maes, C., and T. J. O’Kane (2014), Seasonal variations of the upper ocean salinity stratification in the Tropics, J. Geophys. Res. Oceans, 119, 1706–1722, doi:10.1002/2013JC009366.
Tipo: Dataset
Palavras-chave: Salinity; Oceanography; Stratification.
Ano: 2014
URL: http://dx.doi.org/10.17882/41101

The main pycnocline in the North Atlantic subtropical gyre from Argo Data
Provedor de dados: 5
Autores: Feucher, Charlene; Maze, Guillaume; Mercier, Herle.
In the north Atlantic subtropical gyre, the oceanic vertical structure of density is characterized by a region of rapid increase with depth. This layer is called the permanent pycnocline because this density feature is observed throughout the year. The pycnocline is the transition layer between light, low-latitude, surface water masses which are ventilated every winter when penetrated locally by the mixed layer and dense, deeper water masses whose properties are set in the high latitudes and circulate equatorward. In-situ data from the Argo array provide temperature/salinity profiles allowing the characterization in space and time of the permanent pycnocline. We thus developed a new method to characterize its depth, thickness and thermohaline...
Tipo: Text
Palavras-chave: Argo; Quality Control; Pattern; Clustering; North Atlantic; Subtropical gyre; Stratification.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00242/35315/33838.pdf

Structure spatiale et cartographie des peuplements benthiques du bassin de Marennes- Oléron : première approche par la méthode du krigeage
Provedor de dados: 5
Autores: Bacher, Cedric; Sauriau, Pierre-guy.
Les peuplements benthiques du bassin de Marennes-Oléron  ont été échantillonnées au printemps 1984 dans le but d'étudier le stock des compétiteurs  des populations de filtreurs cultivés (huître Crassostrea  gigas et moule Mytilus edulis). 370 échantillons ont été prélevés sur une surface d'étude de 18Okm2 en utilisant un plan aléatoire stratifié. Les résultats ont été regroupés en deux groupes d'espèces ayant des stratégies nutritionnelles différentes (mollusques déposivores ou suspensivores).  Ces deux groupes trophiques ont été cartographiés, après une transformation logarithmique en utilisant la technique du krigeage. Pour chaque groupe  trois modèles de structure spatiale ont été utilisés: covariance généralisée, semi-variogrammme unidirectionnel ou...
Tipo: Text
Palavras-chave: France; Estimation stocks; Structure spatiale; Stratification; Peuplement benthique; Bassin Marennes Oléron; Cartographie; Modélisation.
Ano: 1995
URL: http://archimer.ifremer.fr/doc/1995/acte-6863.pdf

Stratification structure in subtropical gyres and its decadal variability in the North Atlantic Ocean
Provedor de dados: 5
Autores: Feucher, Charlene.
Subtropical gyres are central to the observed climate changes throughout the last decades. It is observed between the surface and the permanent pycnocline an intense increase in the ocean heat content. The permanent pycnocline delineates thus an important heat reservoir. The permanent pycnocline has a major role in preventing heat to reach the deep ocean and it thus of a relative importance in the context of climate change. For the first time and thanks to the development of the Argo array, we have been able to characterize the observed structure of the permanent pycnocline. The objective of this PhD thesis is to investigate the structure of the permanent pycnocline and its variability over the last decades. We developed an objective method to characterize...
Tipo: Text
Palavras-chave: Pycnocline permanente; Stratification; Contenu de chaleur; Variabilité décennale; Argo; Réanalyses océaniques; Gyres subtropicaux; Atlantique nor; Permanent pycnocline; Stratification; Heat content; Decadal variability; Argo; Ocean reanalyses; Subtropical gyres; North Atlantic.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00366/47675/47721.pdf

Influence of morphological changes on suspended sediment dynamics in a macrotidal estuary: diachronic analysis in the Seine Estuary (France) from 1960 to 2010
Provedor de dados: 5
Autores: Grasso, Florent; Le Hir, Pierre.
Estuaries are subject to extensive morphological changes through human activities, such as deepening and narrowing via dredging and channelization. The estuary sediment load, characterised by the estuarine turbidity maximum (ETM), can severely increase in response to channel deepening, shifting the estuary from a natural to hyperturbid state. The main processes driving the estuarine circulation, hydrology and sediment dynamics are relatively well known. However, their relative influence on suspended sediment concentration (SSC), as well as their role in the transition toward hyperturbid estuaries, is still a subject of debate. Therefore, this study aims at investigating the relative contribution of key estuarine drivers (gravitational circulation and tidal...
Tipo: Text
Palavras-chave: Estuary deepening and narrowing; Sediment dynamics; Turbidity maximum; Tidal asymmetry; Stratification; Numerical modelling; Morphological changes.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00479/59046/65965.pdf

Masas de agua en la plataforma continental
Provedor de dados: 20
Autores: Guerrero, R.A.; Piola, A.R.
The current knowledge on the argentine continental shelf water masses is summarized in this paper. These water masses are characterized as a function of water types fed by the boundary currents and the modifications due to continental runoff, and water energy exchange with the atmosphere. Based on sea surface salinity distributions and the temperature-salinity characteristics, three masses are described: coastal waters, mid-shelf waters and slope waters. The main freshwater sources found along the coast are identified, as well as high salinity formation areas. The vertical stratification, mainly controlled by temperature, is analyzed along the annual cycle. The stratification cycle is mainly driven by the heat exchange between the atmosphere and the ocean....
Tipo: Book Section
Palavras-chave: Continental shelves; Water masses; Hydrography; Water circulation; Oceanic fronts; Stratification; Water circulation; Stratification; Hydrography; Continental shelves; Http://aims.fao.org/aos/agrovoc/c_8314; Http://aims.fao.org/aos/agrovoc/c_7438; Http://aims.fao.org/aos/agrovoc/c_3727; Http://aims.fao.org/aos/agrovoc/c_32413.
Ano: 1997
URL: http://hdl.handle.net/1834/1703

SEED DORMANCY BREAKING TREATMENTS FORAFRICAN PURSLANE (Zaleya pentandra)
Provedor de dados: 87
Autores: MUNAWAR,S.; NAEEM,M.; ALI,H.H.; JAMIL,M.; IQBAL,M.; NAZIR,M.Q.; BALAL,R.M.; SAFDAR,M.E.
ABSTRACT Understanding the mechanisms involved in releasing seed dormancy is crucial for effective plant management and renewal of species in the arid zone. Zaleya pentandra is an emerging invasive weed of the arid areas of Pakistan. We investigated the effects of different dormancy breaking treatments on the germination of Z. pentandra seeds. Seeds were treated with hot water (by placing them in boiling water for 5, 15, 30, 60, 90, 120, and 150 min), dry heat (by placing them in a preheated oven at 70 oC for 1, 2, and 4 hours; at 70 oC for 1, 2, 3, and 4 days, and at 200 oC for 5, 10, 15, 30, and 45 min) and stratification (by placing them at 2-5 ºC in a refrigerator for 5, 10, 30, and 60 min; for 3, 6, and 12 hours, and for 1, 2, 4, 8, 15, and 30 days)....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Germination; Scarification; Stratification; Dry heat; Thiourea; Arid zone.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582015000400623

PANEL STRATIFICATION IN META-ANALYSIS OF ECONOMIC STUDIES: AN INVESTIGATION OF ITS EFFECTS IN THE RECREATION VALUATION LITERATURE
Provedor de dados: 31
Autores: Rosenberger,   Randall S.; Loomis,   John B.
Statistical summarizations of literature review databases using meta-regression analysis provide insight into the differences in past estimates of economic variables such as benefits and price elasticities.  The panel nature of the data is an issue that has not received adequate attention in past meta-analyses.  This paper conceptually and empirically explores the complexity of stratifying data into panels that model the potential correlation and heterogeneity of past outdoor recreation benefit research. Although our tests of three stratifications of the data did not discern panel effects, the inherent complexity of the data maintains a strong presumption of heterogeneous strata.
Tipo: Journal Article
Palavras-chave: Meta-analysis; Outdoor recreation economic benefits; Panel data; Stratification; Resource /Energy Economics and Policy.
Ano: 2000
URL: http://purl.umn.edu/15310

Estrutura e diversidade do componente arbóreo da floresta na Estação Ecológica dos Caetetus, Gália, SP
Provedor de dados: 88
Autores: DURIGAN,GISELDA; FRANCO,GERALDO ANTÔNIO DAHER CORRÊA; SAITO,MASAHIRO; BAITELLO,JOÃO BATISTA.
O estudo fitossociológico, se realizado em diferentes estratos verticais da floresta, fornece dados de grande valia para a compreensão da dinâmica da comunidade. Efetuou-se levantamento das espécies arbóreas presentes em diferentes estratos, em área de 6.000 m² de floresta madura, na Estação Ecológica dos Caetetus, Gália, SP. Foram utilizadas 60 parcelas de 10 x 10 m, para indivíduos com diâmetro do caule a 1,30 m acima do nível do solo (DAP) a partir de 5 cm (estrato superior); 10 x 2 m, para indivíduos com DAP entre 1 e 5 cm (estrato intermediário) e 60 sub-parcelas de 2 x 2 m, para indivíduos menores que 1 cm de DAP (estrato inferior). Verificou-se que a diversidade, a composição florística e a densidade relativa das espécies variam entre estratos. No...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Seasonal semideciduous forest; Phytosociology; Stratification.
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042000000400003

Effects of erosion and deposition on particle size distribution of deposited farmland soils on the chinese loess plateau
Provedor de dados: 90
Autores: Zhao,Pei; Shao,Ming An; Omran,Wail; Amer,Abdel-monem Mohamed.
Particle size distribution (PSD) in the soil profile is strongly related to erosion, deposition, and physical and chemical processes. Water cycling and plant growth are also affected by PSD. Material sedimented upstream of the dam constructions formed large areas of deposited farmland (DF) soils on the Chinese Loess Plateau (CLP), which has been the site of the most severe soil erosion in the world. Two DFs without tillage on the CLP were chosen to study the combined effect of erosion and check dams on PSD. Eighty-eight layers (each 10 cm thick) of filled deposited farmland (FDF) soils and 22 layers of silting deposited farmland (SDF) soils of each studied soil profile were collected and 932 soil samples were investigated using laser granulometry. The...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Soil texture; Stratification; Soil erodibility; Dam construction; Soil conservation.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832011000600028

Vertical and time distribution of Diplopoda (Arthropoda: Myriapoda) in a monodominant forest in Pantanal of Mato Grosso, Brazil
Provedor de dados: 103
Autores: Battirola,Leandro D.; Marques,Marinêz I.; Rosado-Neto,Germano H.; Pinheiro,Tamaris G.; Pinho,Nelsina G. C.
In this study different sampling techniques for Diplopoda in soil, tree trunks and canopies were applied in an integrated way in the northern region of the Pantanal of Mato Grosso, Brazil. This was done in order to assess the relationship within the fauna in each forest strata, as well as its richness and temporal distribution. In all these habitats there were a total of 1,354 diplopods, distributed in four taxonomic orders, with Polyxenida being predominant over Polydesmida, Spirostreptida and Spirobolida. The largest representation was found on the trunks of the Vochysia divergens (721 ind.), intercepted by tree photoecletors, whereas in the canopies sampling reached only 65 specimens. In the edaphic stratum 568 diplopods were captured, most with the use...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Diplopoda; Ecology; Stratification; Wetlands.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702009000300012

Vertical structure of an assemblage of bats (Mammalia: Chiroptera) in a fragment of Atlantic Forest in Southern Brazil
Provedor de dados: 103
Autores: Carvalho,Fernando; Fabián,Marta E.; Menegheti,João O.
Few studies have focused the vertical structure of bat assemblages, and how it influences community composition. The goal of this study was to analyze the vertical structure of an assemblage of bats in a forest fragment in southern Brazil. Bats were sampled using mist-nets placed at three heights (understory, below-canopy, and canopy). Forest strata were compared with respect to their species richness and diversity. The latter was estimated using the Shannon-Wiener index (H'), and the statistical significance of differences among strata was assessed using t tests. We used an index of Constancy (C) to determine the frequency of a given species in each vegetation stratum, such that a species was considered as "frequent" (C &amp;gt; 50), "less frequent" (25...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Diversity; Phyllostomidae; Richness; Stratification; Vespertilionidae.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702013000500004

Seed conditioning of red oak: a recalcitrant North American seed
Provedor de dados: 63
Autores: Struve,D.K.
A ten day aerated water soak was developed as a seed conditioning treatment for red oak (Quercus rubra L.). Conditioned seeds had higher germination completeness, uniformity and speed compared to control seeds. Seeds could be conditioned under a wide range of temperatures and durations. Conditioned seeds were maintained at 7(0)C for 30 days without loss of seed quality. During conditioning, pericarps split in response to seed hydration. Split pericarps could be used as a pre-sowing indicator for high quality seeds. Seed conditioning was ineffective on dormant seeds. Increased crop uniformity and higher stand establishment can be realized by subjecting red oak acorns to an aerated water soak treatment followed by selecting seeds with split pericarps. These...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Quercus rubra; Acorns; Stratification; Aerated water soak; Germination capacity; Seed storage; Seedling quality.
Ano: 1998
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161998000500012

Efeitos da fragmentação florestal sobre vespas e abelhas solitárias na Amazônia Central. II. estratificação vertical
Provedor de dados: 104
Autores: Morato,Elder Ferreira.
The effects of forest fragmentation on the patterns of vertical abundance and richness of solitary wasp and bee communities was investigated near Manaus, Amazonas. Wasps and bees were trap-nested at 1,5, 8 and 15 m above the ground in continuous primary forestand isolated forest fragments. In general, the number of nests and species increased with height for both groups. In particular, bee species richness at 15 m was almost twice that at 1,5 mm. However, one species of Trypoxylon Latreille, 1796 (Sphecidae) consistently nested in the understorey. Thus, patterns of abundance and richness distributions indicated stratification. A contingency analysis showed that fragmentation altered stratification of nesting activity of the wasp community in fragments....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Forest fragmentation; Amazonia; Stratification; Solitary wasps; Solitary bees.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81752001000300010

Preferência por estratos florestais e por substâncias odoríferas em abelhas Euglossinae (Hymenoptera, Apidae)
Provedor de dados: 104
Autores: Oliveira,Mareio Luiz de; Campos,Lúcio Antônio de Oliveira.
Euglossinae bees of two areas of Terra Firme forest, near Manaus, Amazonas, Brazil were studied. During one year the collections were done fortnightly, using traps with eight kinds of scent baits. The traps were placed in the understory and in tree crowns. Some species showed a very clear vertical stratification in the forest. The comparison between the strata studied showed that the fauna of one understory is more similar to other than fauna of crowns and the similarity between fauna of understory and fauna of crown of the the two areaswas low. Some species were specialists while most were generalists in their choice of scent baits. Some species varied its preferences during the year.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Amazônia; Euglossinae; Scent baits preferences; Stratification.
Ano: 1996
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81751996000400025

Impact of artificial destratification on water availability of reservoirs in the Brazilian semiarid
Provedor de dados: 42
Autores: LIMA NETO,IRAN E.
Abstract: Field surveys and integral modelling were carried out to study the effect of bubble plumes on the flow hydrodynamics and the time-evolution of water temperature profiles in a shallow lake with maximum depth of about 4 m. Then, model simulations were performed to verify the feasibility of destratification of ten water-supply reservoirs with capacities of 10-2,000 hm3. Finally, hydrological modelling was conducted to assess the impact of destratification on evaporation suppression and its effects on reservoir yield. The results indicate that net temperature reductions of the order of 1.0°C can be obtained, which corresponds to evaporation suppressions of approximately 10%. In turn, this resulted in increases in the regulated flow of 2-12% that...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Aeration; Evaporation; Bubble plumes; Lakes; Stratification; Water yield.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652019000500904

Competitiveness levels in cattle herd farms
Provedor de dados: 65
Autores: Marques,Pedro Rocha; Barcellos,Júlio Otávio Jardim; Dill,Matheus Dhein; Dias,Eduardo Antunes; Azevedo,Eduardo Vaz Torres; Lampert,Vinícius do Nascimento; McManus,Concepta Margaret.
The aim of this experiment was to identify improvement demands for farms with different levels of competitiveness in the west of Rio Grande do Sul state, Brazil. A total of 63 owners of large farms were interviewed (farms with an area greater than 900ha) by applying a semi-structured questionnaire, guided by four drivers: technology (TEC), management (MAN), market relations (MR) and the institutional environment (IE).It was used the Statistical Analysis System 9.2 software to perform the cluster analysis and identify farmers' characteristics. Three random clusters with different levels of competitiveness were observed: low competitiveness level (LCL), middle competitiveness level (MCL) and high competitiveness level (HCL). The 29 variables (sub factors)...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cluster; Level of impact; Management; Ranking; Stratification.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782015000300480

Dormancy overcome and seedling quality of pecan in nursery
Provedor de dados: 65
Autores: Poletto,Tales; Muniz,Marlove Fátima Brião; Poletto,Igor; Stefenon,Valdir Marcos; Maciel,Caciara Gonzatto; Rabusque,Jéssica Emilia.
ABSTRACT: This study evaluated the efficiency of methods to overcome seed dormancy in different storage periods in the production of pecan seedlings. Seeds were submitted to the following treatments: T1, T4 and T7 - control treatments (seeds with no treatment, stored at room temperature for 30, 60 and 90 days, respectively), T2, T5 and T8 - stratification (seeds were distributed in boxes with wet sand maintained at a temperature of 4°C for 30, 60 and 90 days, respectively), T3, T6 and T9 - scarification + stratification (seeds scarified with sandpaper n.80 and stratified by 30, 60 and 90 days, respectively), in completely random experimental design. Plant height, stem diameter, number of leaves, full emergence and emergence speed index (ESI) were evaluated...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Scarification; Stratification; Emergence; Carya illinoinensis.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782016001101980