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| Registros recuperados: 223 | |
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| Deen, M.; Stutzmann, Eleonore; Ardhuin, Fabrice. |
| The Earth's hum is the continuous oscillations of the Earth at frequencies between 2 and 20 mHz in the absence of earthquakes. The hum strongest signal consists mainly of surface waves. These seismic waves can be generated by infragravity waves propagating over a sloping ocean bottom close to the coast. So far, this theory has only been tested quantitatively using European seismic stations. We use seismic data recorded all around the Indian Ocean together with an ocean wave model that provides time‐frequency varying hum sources. We show that seasonal variations of the hum sources are smaller in the southern hemisphere (SH) than the northern hemisphere (NH). Using these sources, we model Rayleigh wave RMS amplitudes in the period band 3.5‐20 mHz, and the... |
| Tipo: Text |
Palavras-chave: Seismic hum; Infragravity waves; Indian Ocean; Seismic noise; Hum sources; Modeling. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00455/56678/58435.pdf |
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| Payo-payo, Marta; Silva Jacinto, Ricardo; Lastras, G.; Rabineau, Marina; Puig, P.; Martin, J.; Canals, M.; Sultan, Nabil. |
| Bottom trawling leads to recurrent sediment resuspension events over fishing grounds. Recent studies have shown how bottom trawling can drive seascape reshaping at large spatial scales and enhance sediment transport in submarine canyons, which subsequently impacts deep-sea ecosystems. Present knowledge on the transfer and accumulation of sediment flows triggered by bottom trawling is based on localized and infrequent measurements whilst a more complete picture of the process is needed. The present work focuses on the modeling of sediment transport and accumulation resulting from trawling activities in La Fonera submarine canyon, northwestern Mediterranean Sea, thus contributing to an improved assessment of trawling impacts. Based on mooring data within a... |
| Tipo: Text |
Palavras-chave: Bottom trawling; Inverse model; Modeling; Sediment transport; Submarine canyon; Turbidity currents. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00374/48549/48862.pdf |
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| Gonzalez, Jean-louis; Thouvenin, Benedicte; Dange, Catherine; Chiffoleau, Jean-francois; Boutier, Bernard. |
| The role of particles in the fate and speciation of trace metals in macrotidal estuaries was studied using a surface complexation model (MOCO). Cadmium was selected as the target metal contaminant due to its reactivity in estuaries: cadmium behavior is mainly controlled by heterogeneous processes (sorption/desorption) related to salinity and suspended matter gradients. Various scenarios of suspended matter distribution according to salinity were simulated. The impact of surface properties (specific surface area, density of surface sites, acido-basic properties, and complexation constant) was evaluated using data collected on particles from the Gironde, Loire, and Seine estuaries. Our results show that particle surface properties, evaluated on the basis... |
| Tipo: Text |
Palavras-chave: Turbidity maximum; Speciation; Sorption; Particles; Modeling; Macrotidal estuaries; Cadmium. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2005.pdf |
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| Thouvenin, Benedicte; Gonzalez, Jean-louis. |
| Within the framework of the "Contaminants cycle and modeling" project of the BE department ("Biogeochemistry and Ecotoxicology") in Ifremer, two chemical contaminant modeling software were developed between 1998 and 2011 (Gonzalez JL, 2017): the MORGAN model (Model behavior of ORGANic contaminants in an aquatic environment) and the MOCO model (Surface Complexation MOdel for metallic COntaminants). These two models had been brought together in a single "zero-dimensional" software (known as MOMO), which made it possible to simulate the various processes affecting the behavior of chemical contaminants in a homogeneous mass of water (biodegradation, adsorption/desorption, photolysis, hydrolysis, volatilization, surface complexation, cation exchange,... |
| Tipo: Text |
Palavras-chave: Modelisation; Biogeochimie; Contaminants métalliques et organiques; Spéciation; Modeling; Biochemical; Trace metals - organic contaminants; Speciation. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00686/79771/82993.pdf |
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| Lu, Zhen Quan; Sultan, Nabil; Jin, Chun Shuang; Rao, Zhu; Luo, Xu Rong; Wu, Bi Hao; Zhu, You Hai. |
| Based on field investigated gas geochemistry and predecessors' data such as the permafrost ground temperature, thermal gradients within/below the frozen layer, the modeling on gas hydrate formation conditions is conducted in the Qinghai Tibet plateau permafrost. The modeled results show that the permafrost characteristics generally meet gas hydrate formation conditions in the study area. Gas composition, temperature-related permafrost parameters (e. g. permafrost thickness or its ground temperature and thermal gradients within / below the frozen layer) are the most important factors affecting gas hydrate occurrences, whose variance may cause the heterogeneity of gas hydrate occurrences in the study area. The most probable gas hydrate is the kind of hybrid... |
| Tipo: Text |
Palavras-chave: Qinghai Tibet plateau; Modeling; Formation conditions; Gas hydrate; Permafrost. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6230.pdf |
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| Giraud, Mélanie; Garçon, Véronique; De La Broise, Denis; L'Helguen, Stéphane; Sudre, Joël; Boye, Marie. |
| Installation of an Ocean Thermal Energy Conversion pilot plant (OTEC) off the Caribbean coast of Martinique is expected to use approximately 100,000 m3 h−1 of deep seawater for its functioning. This study examined the potential effects of the cold nutrient-rich deep seawater discharge on the phytoplankton community living in the surface warm oligotrophic waters before the installation of the pilot plant. Numerical simulations of deep seawater upwelled by the OTEC, showed that a 3.0 °C temperature change, considered as a critical threshold for temperature impact, was never reached during an annual cycle on the top 150 m of the water column on two considered sections centered on the OTEC. The thermal effect should be limited, <1 km2 on the area exhibited... |
| Tipo: Text |
Palavras-chave: Marine microbial ecosystem; Biogeochemistry; Modeling; Artificial seawater discharge in situ experiments; Environmental standards. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00507/61867/65935.pdf |
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| Guardans, Ramon; Castro-jimenez, Javier. |
| The presence of toxic substances such as persistent organic pollutants (POPs) in the environment, and in organisms including humans, is a serious public health and environmental problem, even at low levels and poses a challenging scientific problem. The Stockholm Convention on POPs (SC) entered into force in 2004 and is a large international effort under the United Nations Environment Programme (UNEP) to facilitate cooperation in monitoring, modeling and the design of effective and fair ways to deal with POPs globally. This paper is a contribution to the ongoing effectiveness evaluation (EE) work aimed at the assessment and enhancement of the effectiveness of the actions undertaken under the SC. First we consider some aspects related to the monitoring of... |
| Tipo: Text |
Palavras-chave: POPs monitoring; Modeling; Stockholm Convention effectiveness; Global Monitoring Plan. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00645/75724/76673.pdf |
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| Damour, Valentin. |
| This report is about the work realized during a part time training at Ifremer. The subject discussed in this paper will associate the maritime field and the computer science field. It proves that computer science is really a multipurpose domain. In a context of global warming and human pressure (pollution and ressources over-exploitation), the marine ecosystem is jeopardized. In order to have a better understanding of the situation of this habitat and to stem these brutal changes, it is important to observe and gather information about it. It is exactly the goal of the project I took part in. This project mainly deals with observing sea turtles in their natural habitat. Thoses observations are realized thanks to LoRa equiped tags which are implanted on... |
| Tipo: Text |
Palavras-chave: Réseau tolérant au délai; Océan Indien; Tortues marines; Modélisation; Delay-tolerant network; Indian Ocean; Sea turtles; Modeling. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00612/72364/71279.pdf |
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| Cysneiros, Vinicius Costa; Amorim, Thiago de Azevedo; Mendonça Júnior, Joaquim de Oliveira; Gaui, Tatiana Dias; de Moraes, Juan Carlos Resende; Braz, Denise Monte; Machado, Sebastião do Amaral. |
| O objetivo do presente estudo foi avaliar o desempenho e selecionar funções densidade de probabilidade que descrevam a distribuição diamétrica da comunidade florestal e das três principais espécies da Floresta Ombrófila Densa no sul do estado do Rio de Janeiro. Foram testadas as funções Normal, Log Normal, Beta, Gama, Sb de Johnson e Weibull. Os ajustes foram realizados com auxílio da ferramenta Solver (MSExcel®), que utiliza o algoritmo linear de gradiente reduzido para otimização dos parâmetros das funções. Para a seleção do melhor modelo foram avaliados o valor D de Kolmogorov – Smirnov e o erro padrão da estimativa (Syx %). De maneira geral, as funções Sb de Johnson e Weibull apresentaram as melhores estatísticas de ajuste e maior precisão nas... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Recursos Florestais; Engenharia Florestal; Dendrometria Floresta Atlântica; Funções densidade de probabilidade; Modelagem Atlantic Forest; Density probability functions; Modeling. |
| Ano: 2017 |
URL: http://pfb.cnpf.embrapa.br/pfb/index.php/pfb/article/view/1070 |
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| Cordeiro, Márcio Assis; Pereira, Nayara Natacha de Jesus; Binoti, Daniel Henrique Breda; Binoti, Mayra Luiza Marques da Silva; Leite, Hélio Garcia. |
| The present study aimed to show the results of Acacia mangium volumetric estimates obtained through the Schumacher and Hall model compared to the methods of artificial neural networks and support vector machines. To enable this comparative analysis, we used data from 31 trees of Acacia mangium aged 14–17, from a stand located in the northern region of the state of Amapá. Diameter and bark thickness of the trees were measured into relative heights along the stem into 14 sections (0.05%, 1%, 5%, 10%, 15%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 95%), with measurement. Total volume with bark was obtained by applying the Smalian formula. In general, the methods that differ from traditional methods showed statistically superior results. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Smalian; Modeling; Volumetric estimates Engenharia Florestal Manejo Florestal Recursos Florestais Smalian; Modelagem; Estimativa volumétrica. |
| Ano: 2015 |
URL: http://pfb.cnpf.embrapa.br/pfb/index.php/pfb/article/view/596 |
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| Protásio, Thiago de Paula; Bufalino, Lina; Tonoli, Gustavo Henrique Denzin; Couto, Allan Motta; Trugilho, Paulo Fernando; Guimarães Júnior, Mário. |
| The aims of this work were to evaluate the correlation, to adjust and select simple and multiple linear statistical models between elemental components (carbon, hydrogen and oxygen) and ash content with higher heating value for plant biomass; to use the principle components analysis for the creation of an energetic development index and to adjust a linear model between energetic development index and higher heating value. Eight types of biomass were used. Three linear and nine multiple statistical models were adjusted. The best models were selected based on the significance of coefficients, adjusted determination coefficient, estimative standard error, coefficient of variation, linearity of parameters, normality, presence of heterocedasticity and lack of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Modeling; Regression; Correlation; Selection Modelagem; Regressão; Correlação; Seleção. |
| Ano: 2011 |
URL: http://pfb.cnpf.embrapa.br/pfb/index.php/pfb/article/view/200 |
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| Richter,Gean Leonardo; Streck,Nereu Augusto; Zanon,Alencar Junior; Ulguim,André da Rosa; Kruse,Nelson Diehl; Santos,Gionei Alves de Assis dos; Cera,Jossana Ceolin; Ribas,Giovana Ghisleni; Duarte Junior,Ary José; Pilecco,Isabela Bulegon. |
| Abstract: The objective of this work was to model weedy rice (Oryza sativa) and barnyard grass (Echinochloa spp.) competition with flood-irrigated rice, introducing it as a submodule into the SimulArroz model. The competition of both weeds with irrigated rice was modeled using the rectangular hyperbola equation. The “i” and “a” coefficients of the rectangular hyperbola for each of these weeds were obtained from the literature and from field experiments carried out in the state of Rio Grande do Sul, Brazil. In SimulArroz, yield loss was applied to penalize yield in all three technological levels (high, medium, and low) of physiological maturity. For weedy rice, the coefficient values of imean for the high, medium, and low technological levels were 1.04,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Oryza sativa; Barnyard grass; Modeling; Weedy rice; Yield loss. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2019000102508 |
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| Streck,Nereu Augusto; Lago,Isabel; Gabriel,Luana Fernandes; Samboranha,Flavia Kaufmann. |
| The objective of this study was to adapt a nonlinear model (Wang and Engel - WE) for simulating the phenology of maize (Zea mays L.), and to evaluate this model and a linear one (thermal time), in order to predict developmental stages of a field-grown maize variety. A field experiment, during 2005/2006 and 2006/2007 was conducted in Santa Maria, RS, Brazil, in two growing seasons, with seven sowing dates each. Dates of emergence, silking, and physiological maturity of the maize variety BRS Missões were recorded in six replications in each sowing date. Data collected in 2005/2006 growing season were used to estimate the coefficients of the two models, and data collected in the 2006/2007 growing season were used as independent data set for model evaluations.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zea mays; Degree days; Development; Modeling; Thermal time. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2008000400002 |
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| Fernandes,Felipe Augusto; Fernandes,Tales Jesus; Pereira,Adriele Aparecida; Meirelles,Sarah Laguna Conceição; Costa,Adriano Carvalho. |
| Abstract: The objective of this work was to evaluate how the parameterization and the application of different allometric values affect the obtention of the most adequate fit of von Bertalanffy’s model, in the description of the growth curve of meat-producing mammals (bovine, pigs, rabbits, and sheep). Among the nonlinear models, von Bertalanffy’s has been very often applied in several areas, with different parameterizations. This model has been commonly used with an allometric value of m = 2/3; however, for mammals, it is believed that this value can be m = 3/4. The analyzed data referring to the mass of meat-producing mammals according to their age were obtained from research institutions and from the literature. The results showed that von Bertalanffy’s... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Allometry; Modeling; Nonlinear model; Parameterization; Regression. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2019000104307 |
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| Streck,Nereu Augusto; Uhlmann,Lilian Osmari; Gabriel,Luana Fernandes. |
| The objective of this work was to test long-term trends in the duration of rice development phases in Santa Maria, RS, Brazil. The duration from emergence to V3 (EM-V3), emergence to panicle differentiation (EM-R1), emergence to anthesis (EM-R4), and emergence to all grains with brown hull (EM-R9) was calculated using leaf appearance and developmental models for four rice cultivars (IRGA 421, IRGA 417, EPAGRI 109, and EEA 406), for the period from 1912 to 2011, considering three emergence dates (early, mid, and late). The trend of the time series was tested with the non-parametric Mann-Kendall test, and the magnitude of the trend was estimated with simple linear regression. Rice development has changed over the last ten decades in this location, leading to... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Oryza sativa; Development rate; Global warming; Growing season; Maturity group; Modeling; Phenology. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2012000600001 |
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| Souza,Felipe Amorim Caetano de; Fernandes,Tales Jesus; Cunha,Fabiana Oliveira; Ribeiro,Rafaela Aparecida; Muniz,Fabiana Rezende; Meirelles,Sarah Laguna Conceição; Muniz,Joel Augusto; Moura,Raquel Silva. |
| Abstract: The objective of this work was to evaluate the development of the morphometric characteristics of Mangalarga Marchador horses through nonlinear models. The transversal method was used to collect data on height at the withers (HW), body length (BL), and thoracic (TP) and cannon (CP) perimeters from 200 horses (75 males and 125 non-pregnant females), aged between 6 and 153 months. The parameters of the Brody, Gompertz, logistic, and von Bertalanffy nonlinear models were estimated using the R software. Models were compared and selected using the coefficient of determination, the residual standard deviation, and the corrected Akaike information criterion. For adult females, HW, BL, TP, and CP ranged between 146.45-148.34, 148.59-151.64,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Equus caballus; Brody; Gompertz; Logistic; Modeling; Von Bertalanffy. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2019000104308 |
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| Medeiros,Reginaldo Antonio; Paiva,Haroldo Nogueira de; D’Ávila,Flávio Siqueira; Leite,Helio Garcia. |
| Abstract: The objective of this work was to evaluate the growth and yield of teak (Tectona grandis) stands at different spacing and in different soil classes. Twelve spacing were evaluated in an Inceptisol and Oxisol, in plots with an area of 1,505 or 1,548 m2, arranged in a completely randomized design with nine replicates. The teak trees were measured at 26, 42, 50, and 78 months of age. Total tree height was less affected by spacing. Mean square diameter was greater in wider spacing, whereas basal area and total volume with bark were greater in closer spacing. An increase in volume with bark per tree was observed with the increase of useful area per plant. For teak trees, growth stagnation happens earlier, the growth rate is higher in closer spacing,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Tectona grandis; Initial spacing; Modeling. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2018001001109 |
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| Registros recuperados: 223 | |
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