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| Registros recuperados: 103 | |
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| Feki-Sahnoun, W.. |
| Le long des côtes du golfe de Gabès, les données collectées dans le cadre du Réseau de Surveillance du Phytoplancton et des Phycotoxines (REPHY), constituent une base pertinente pour examiner la structure et la dynamique des communautés phytoplanctoniques à grandes échelles temporelle (1997-2007) et géographique (l’ensemble de littoral du golfe). S’appuyant sur les données du REPHY, l’objectif de cette étude était de décrire les principales formes de variabilité des communautés phytoplanctoniques observées sur nos côtes. Les schémas de la variabilité des populations phytoplanctoniques ont été examinés à différentes échelles temporelles et géographiques à l’aide de méthodes statistiques multivariées. Dans un premier temps, l’analyse de la dynamique des... |
| Tipo: Theses and Dissertations |
Palavras-chave: Phytoplankton; Temporal variations; Geographical distribution; Statistical analysis; Models. |
| Ano: 2013 |
URL: http://hdl.handle.net/1834/5444 |
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| Firpo, C.; Wyngaard, J.; Iorio, M.I.. |
| To standardize false king crab catch rates and transform them into abundance indices it is essential to count on a model that adequately describes the relation between catch per trap and fishing time. Considering data derived from research surveys carried out on board of the artisanal fleet in the Beagle Channel, assuming an asymptotic catch trend and absence of escape, to describe the relation an exponential model was applied. The Coo (asymptotic catch) and a (income rate) parameters of the model allowed to build a correction factor to transform the catches obtained with different fishing times into relative abundance indices. The model provides, besides, the optimum time to maximize catches. Para estandarizar las tasas de captura de centollón y... |
| Tipo: Journal Contribution |
Palavras-chave: Fishing time; Trap nets; Catch statistics; Models; Fishery surveys; Abundance; Paralomis granulosa; Marine environment. |
| Ano: 2014 |
URL: http://hdl.handle.net/1834/5822 |
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| Protásio, Thiago de Paula; Santana, João de Deus Pereira de; Guimarães Neto, Rosalvo Maciel; Guimarães Júnior, José Benedito; Trugilho, Paulo Fernando; Ribeiro, Ioleide Bispo. |
| This work aimed to verify the influence of the sampling longitudinal position in Qualea parviflora Mart. in the quality of charcoal and the statistical relation among the variables measured in this biofuel. Five trees were evaluated. In each one, 5 cm – thickness discs were obtained in the base, DBH (1.30 m), middle and top. The wood was carbonized in a muffle furnace, considering a heating rate of 1.67 ºC min-1. The yields in charcoal pyroligneous extract, in non-condensable gases and in fixed carbon and volatile matters, fixed carbon and ash contents, besides relative apparent density of the charcoal were determined. In the evaluation of the experiment, an entirely randomized design was used with five repetitions, being different sampling position... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Pyrolysis; Correlations; Sampling; Models. |
| Ano: 2011 |
URL: http://pfb.cnpf.embrapa.br/pfb/index.php/pfb/article/view/276 |
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| Kogan,Marcelo; Metz,Alejandra; Ortega,Rodrigo. |
| The objective of this work was to investigate glyphosate adsorption by soils and its relationship with unoccupied binding sites for phosphate adsorption. Soil samples of three Chilean soils series - Valdivia (Andisol), Clarillo (Inceptisol) and Chicureo (Vertisol) - were incubated with different herbicide concentrations. Glyphosate remaining in solution was determined by adjusting a HPLC method with a UV detector. Experimental maximum adsorption capacity were 15,000, 14,300 and 4,700 mg g¹ for Valdivia, Clarillo, and Chicureo soils, respectively. Linear, Freundlich, and Langmuir models were used to describe glyphosate adsorption. Isotherms describing glyphosate adsorption differed among soils. Maximum adjusted adsorption capacity with the Langmuir model... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Herbicide; Dosage effects; Models. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2003000400010 |
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| Bastos,Edson Alves; Folegatti,Marcos Vinícius; Faria,Rogério Teixeira de; Andrade Júnior,Aderson Soares de; Cardoso,Milton José. |
| The objective of this work was to adapt the CROPGRO model, which is part of the DSSAT system, for simulating the cowpea (Vigna unguiculata) growth and development under soil and climate conditions of the Baixo Parnaíba region, Piauí State, Brazil. In the CROPGRO, only input parameters that define crop species, cultivars, and ecotype were changed in order to characterize the cowpea crop. Soil and climate files were created for the considered site. Field experiments without water deficit were used to calibrate the model. In these experiments, dry matter (DM), leaf area index (LAI), yield components and grain yield of cowpea (cv. BR 14 Mulato) were evaluated. The results showed good fit for DM and LAI estimates. The medium values of R² and medium absolute... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Vigna unguiculata; Models; Climatic factors; Edaphic factor; Water availability; DSSAT. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2002001000005 |
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| Huerta,Esperanza; Kampichler,Christian; Geissen,Violette; Ochoa-Gaona,Susana; Jong,Ben de; Hernández-Daumás,Salvador. |
| The objective of this work was to construct a simple index based on the presence/absence of different groups of soil macrofauna to determine the ecological quality of soils. The index was tested with data from 20 sites in South and Central Tabasco, Mexico, and a positive relation between the model and the field observations was detected. The index showed that diverse agroforestry systems had the highest soil quality index (1.00), and monocrops without trees, such as pineapple, showed the lowest soil quality index (0.08). Further research is required to improve this model for natural systems that have very low earthworm biomass (<10 g m-2) and a high number of earthworm species (5-7), as it is in the tropical rain forest, whose soil quality index was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Earthworms; Models; Soil fauna; Soil quality indices. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2009000800039 |
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| Ron,MM; Loewy,T. |
| In the southwest of Buenos Aires Province (Argentina), nitrogen (N) and phosphorus (P) deficiencies are important wheat yield limiting factors. There is an information gap regarding differences between single element and binary N-P sources. The objective of this paper was to develop a general model for N-P fertilization in the area that also quantified diammonium phosphate (DAP) effect and its interactions with N-urea, applied at sowing or tillering, as compared with triple superphosphate (TSP). Between 1984 and 1985, 13 experiments were carried out in farmer’s fields N. With the yield data for each experiment, a yield function was fitted which included terms for single effects of urea (0, 30 and 60 kg N/ha) and 80 kg/ha of either DAP or TSP.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fertilization; Phosphorus sources; Models. |
| Ano: 2016 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1851-56572016000100004 |
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| Bertelsmeier, Marcus; Kleinhanss, Werner; Offermann, Frank. |
| The FAL model group combines several market, regional and farm models for comprehensive policy impact assessments. Since 1996, policy impact analyses have been provided at the request of the German Agricultural Ministry with respect to the design of direct payments, the Agenda 2000, the Mid-term Review, the Enlargement of the EU as well as several other policy measures. This article gives an overview of the models available as part of the model group, specifically describes the design of the representative farm group model, and provides results with respect to the impacts of the Midterm Review. The paper ends with a discussion of the experiences gained in model based policy consulting and the implications for future developments. |
| Tipo: Journal Article |
Palavras-chave: Policy assessment; Models; Agricultural policy; Midterm review; Policy impact analysis; Agricultural and Food Policy. |
| Ano: 2003 |
URL: http://purl.umn.edu/98358 |
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| Registros recuperados: 103 | |
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