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| Registros recuperados: 127 | |
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| 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 & 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| Registros recuperados: 127 | |
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