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| Registros recuperados: 214 | |
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| BARROS,R.E.; FARIA,R.M.; TUFFI SANTOS,L.D.; AZEVEDO,A.M.; GOVERNICI,J.L.. |
| ABSTRACT This study aimed at evaluating the physiology of maize and weeds when living under different densities. The randomized block design with 4 replications was used. The factorial scheme 5 x 2 + 1 and 5 x 3 was adopted, for maize and weeds respectively, corresponding to weed species (Bidens pilosa, Commelina benghalensis, Urochloa brizantha, Sorghum arundinaceum and Ipomoea triloba) and infestation density (control, 15 and 30 plants m-2). Weeds were kept in coexistence with the maize hybrid DKB 390 PRO 2, with an additional treatment for maize plants absent of competition. It was kept in coexistence with maize hybrid DKB 390 PRO 2 besides an additional treatment with maize plants absent of competition. On day 45 and 60 after maize planting (DAP)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zea mays; Urochloa brizantha; Sorghum arundinaceum; Photosynthetic rate; Transpiration; Competition. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582017000100223 |
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| Perruche, Coralie; Riviere, Pascal; Pondaven, Philippe; Carton, Xavier. |
| This paper aims at studying analytically the functioning of a very simple ecosystem model with two phytoplankton species. First, using the dynamical system theory, we determine its nonlinear equilibria, their stability and characteristic timescales with a focus on phytoplankton competition. Particular attention is paid to the model sensitivity to parameter change. Then, the influence of vertical mixing and sinking of detritus on the vertically-distributed ecosystem model is investigated. The analytical results reveal a high diversity of ecosystem structures with fixed points and limit cycles that are mainly sensitive to variations of light intensity and total amount of nitrogen matter. The sensitivity to other parameters such as remineralisation, growth... |
| Tipo: Text |
Palavras-chave: Water mixing; Dynamical system; Phytoplankton; Competition; Ecosystem; Modelling. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/2009/publication-7334.pdf |
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| MARQUES,L.J.P.; BIANCO,S.; C. FILHO,A.B.; BIANCO,M.S.. |
| ABSTRACT Eggplants are vegetables of great importance in the South and Southeast regions of Brazil, which are subject to interference from weeds. In order to collaborate with weed management in this vegetable, this study was carried out to determine the periods of weed interference in growing eggplants. The study was conducted in the Brazilian municipality of Jaboticabal, SP, at the Faculty of Agricultural and Veterinary Sciences, UNESP [Universidade Estadual Paulista "Júlio de Mesquita Filho" (São Paulo State University)], in the period from February to July 2013. The experiment was arranged in a randomized block design with 22 treatments, three replications divided in 11 periods of coexistence and weed control with eggplants: 14, 28, 42, 56, 70, 84, 98,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Solanum melongena; Competition; Productivity; Weed community. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582016000200309 |
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| MILÉO,L.J.; SILVA,J.F.; ALBERTINO,S.M.F.; LEITE,B.N.; MENEZES,D.S.; SANTOS,A.F.. |
| ABSTRACT This study has aimed to carry out a phytosociological survey of weeds in different collection periods, in cassava crops of two varieties grown in two consecutive years. The varieties were Pão, of the sweet class, and Racha-terra, of the bitter class. The weeds surveys were performed at 28, 56, 84, 112, 140, 168, 196, 224, 252, 280 and 308 days after planting in the experimental units of each variety. For weeds sampling, a sampler with an area of 0.25 m2 released twice at random in the floor area of the treatments was used. The phytosociological survey quantified 5,708 individuals distributed in 17 families, represented by 32 species, of which 25 were dicotyledonous and seven were monocotyledonous. The most representative families in number of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Competition; Tillage; Manihot esculenta. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582016000200267 |
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| Feil, Jan-Henning; Musshoff, Oliver. |
| In consequence of changes in general conditions, a higher level of investments and disinvestments in agriculture can be expected. To date, however, there are no policy impact analyses on both investments and disinvestments in competitive agricultural markets in a dynamic-stochastic context. This paper aims to develop a conceptual real options market model, which allows the impact assessment of different political schemes on investment and disinvestment thresholds and the sectoral welfare. Exemplarily, the effects of price floors, investment subsidies and production ceilings are analysed. The results show that the consideration of limited reversibility, that is disinvestments, is of relevance as it can impact the assessment of specific policies. |
| Tipo: Presentation |
Palavras-chave: Real options; Competition; Policy impact analysis; Genetic algoritms; Marketing; Political Economy. |
| Ano: 2012 |
URL: http://purl.umn.edu/124294 |
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| BRAGA,A.F.; BARROSO,A.A.M.; AMARAL,C.L.; NEPOMUCENO,M.P.; ALVES,P.L.C.A.. |
| ABSTRACT: The repetitive use of herbicides with the same mechanism of action causes the selection of resistant weeds, such as ryegrass. Considering the occurrence of ryegrass (Lolium multiflorum) in eucalyptus, a crop on which glyphosate is used, it is necessary to study its interference. The objective of this study was to evaluate the effect of densities (0, 10, 20, 30 and 50 plants m-2) of two ryegrass biotypes (resistant and susceptible to glyphosate) on seedlings of two eucalyptus clones (I-144 and 1407). The used experimental design was in randomized blocks with four replications, following a 2 x 5 factorial arrangement for each clone. The height and diameter of the clones were evaluated at 0, 14, 28, 42, 56 and 70 days after transplantation (DAT),... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lolium multiflorum; Eucalyptus urograndis; Competition. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582018000100286 |
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| Bukeviciute, Lina; Dierx, Adriaan; Ilzkovitz, Fabienne; Roty, Guillaume. |
| Agricultural commodities and consumer food prices have experienced strong variations over the last 2 years, both upwards and downwards. This increased volatility, combined with long-term prospects of rising food prices, highlights the necessity to increase the efficiency of the food supply chain to ensure consumer food prices reflect the evolution of inputs prices. This paper aims at better understanding price transmission mechanisms along the chain across European Union Member States. Significant differences across Member States in magnitude of pass-through of agricultural commodity prices variations to consumer prices, as well as price transmission asymmetries, suggest potential market fragmentation within the EU. Country-specific regulatory frameworks,... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Food; Regulation; Market structure; Competition; Pricing.; Financial Economics. |
| Ano: 2009 |
URL: http://purl.umn.edu/57987 |
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| Bojnec, Stefan. |
| As in many other transition countries processing and marketing margins are also larger in the Slovenian meat market than respective margins in market economies. In addition, margin of the Slovenian pork chain is greater than in the beef chain. Its decline in the pork market indicates an adjustment to more competitive markets. Co-integration models are applied to estimate vertical price transmission and to examine margins and degree of competition in the meat marketing chains. Results indicate the existence of a long run equilibrium regarding vertical price transmission in the beef and pork sectors. Both the farm-gate beef and pork prices are identified as weakly exogenous in the long run. The structural tests imposing a homogeneity restriction suggest a... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Price transmission; Marketing margin; Co-integration; Competition; Marketing; D4; L1; C3; Q1. |
| Ano: 2002 |
URL: http://purl.umn.edu/24789 |
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| Pezzopane,José Ricardo Macedo; Bernardi,Alberto Carlos de Campos; Azenha,Mariana Vieira; Oliveira,Patricia Perondi Anchão; Bosi,Cristiam; Pedroso,André de Faria; Esteves,Sérgio Novita. |
| ABSTRACT This study aimed to evaluate the production characteristics of pastures in integrated livestock production systems. For that, an experiment was carried out in São Carlos, SP, Brazil, from 2013 to 2015. Forage development, production and nutritive value were evaluated in five beef cattle production systems: extensive continuous stocking (Urochloa decumbens) = EXT; intensive = INT; crop-livestock = iCL; livestock-forest = iLF and crop-livestock-forest = iCLF. Rotational stocking pastures in INT, iCL, iLF and iCLF systems were established with Urochloa brizantha cv. BRS Piatã. In iCL and iCLF, pastures were renovated by resowing the grass simultaneously with corn. In iLF and iCLF, eucalyptus (Eucalyptus urograndis clone GG100) was planted in Apr 2011... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Urochloa brizantha; Eucalyptus urograndis; Solar radiation; Competition; Sustainability. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162020000200402 |
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| Casadei,Eloisa; L. Bacha,Allan; S. Rodrigues,Juliana; S. Santos,Renata T.; L.C.A. Alves,Pedro; B.C. Filho,Arthur. |
| Abstract Background: Lettuce-production areas in Brazil are frequently infested by pigweed plants, which can interfere with production by competing for resources or releasing allelopathic compounds in the environment. Objective: The present study evaluated the effect of redroot pigweed (Amaranthus retroflexus) density and distribution on lettuce crop (Lactuca sativa L.). Methods: The cultivars Lídia, Verônica, Lucy Brown and Salad Bowl were used. After transplanting, these plants coexisted until harvest with four pigweed plants (equivalent to 16 plants m-2) located within or outside planting rows, or with one pigweed plant located at the center of the plot (4 plants m-2), as well as a control without weed. The experiment was conducted in an open and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lactuca sativa L.; Amaranthus retroflexus; Competition; Weeds; Density; Distribution. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582020000100308 |
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| AGUIAR,A.C.M.; BASSO,C.J.; SILVA,D.R.O.; GHELLER,D.P.; NOVELLO,B.D.; RIEDER,E.. |
| ABSTRACT: This study evaluated the relative competitiveness of two common bean cultivars in coexistence with volunteer corn emerging at different times in different proportions of plants in the association. Firstly, for both beans and volunteer corn, the plant population was determined in which the final production of dry biomass becomes constant (24 plants pot-1). A completely randomized experiment design, with five replicates, was carried out in a 2×2×5 factorial scheme, involving two common bean cultivars (IPR Gralha and Fepagro Triunfo), two emergence times of volunteer corn plants (-7 and 0 days in relation to beans) and five proportions of plants in the association (100:0, 75:25, 50:50, 25:75 and 0:100). At 35 days after bean emergence, measurements... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Phaseolus vulgaris; Zea mays; Volunteer plants; Competition; Emergence periods; Replacement series. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582019000100294 |
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| Bastiani,Marlon Ouriques; Lamego,Fabiane Pinto; Agostinetto,Dirceu; Langaro,Ana Claudia; Silva,Diônvera Coelho da. |
| ABSTRACT The aim of this work was to evaluate the competitiveness between soybean cultivars and barnyardgrass, based on morphological and physiological characteristics of species. The experiments were conducted in completely randomized experimental design, with 4 replications. In the first study, for both soybean and barnyardgrass, it was determined the population of plants in which shoot dry matter became constant and independent of the population (16 plants∙pot−1 or 400 plants∙m−2). In the second study, 2 experiments were conducted to evaluate the competitiveness of BMX Apolo RR and BMX Potência RR soybean cultivars with barnyardgrass plants, both carried out in replacement series under different proportions of plants∙pot−1 (100:0; 75:25; 50:50; 25:75... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Echinochloa crus-galli; Lowlands; Replacement series; Competition. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052016000400435 |
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| Guillermo-Ferreira,R; Del-Claro,K. |
| Current evidence suggests that in Hetaerina damselflies males exhibit lek mating system. In this study, in order to answer if the same occurs in Hetaerina rosea Selys, we manipulated vegetation substrates used as territories and quantified the number of visiting females, males defending territories and fight intensity. We also examined whether body size and wing pigmentation are selectable traits in male-male competition, and if age affects male territorial behavior. Our results showed that males with larger pigmented areas won more contests, independently of body size. Old males changed from territoriality to sneaking strategy. Contrary to other Hetaerina species, males of H. rosea do not display lek behavior, but defend resources according to the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Competition; Lek; Territoriality; Behavior. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2011000100011 |
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| Vandeputte, Marc; Dupont Nivet, M; Haffray, P; Chavanne, H; Cenadelli, S; Parati, K; Vidal, Marie-odile; Vergnet, Alain; Chatain, Beatrice. |
| Selective breeding of European sea bass (Dicentrarchus labrax) receives a growing interest, as the estimated heritability of growth is medium to high. In this study, we compared the offspring of four groups of sea bass sires, mated with the same wild dams: wild (W), first generation of domestication (D), first generation of mass selection for length (M), first generation of PROSPER-like selection for length (P). The comparison was done both in replicated tanks (separate rearing) and in mixed tanks (mixed rearing) where sire origins were recovered by genotyping of eight microsatellite markers. Weight, length and growth rate were measured from day 238 post-fertilization (69 g mean weight) to day 611 post-fertilization (390 g mean weight). Both in mixed and... |
| Tipo: Text |
Palavras-chave: Nephrocalcinosis; Competition; Microsatellites; Parentage assignment; Realized heritability; Selection response; Growth; Selective breeding; Dicentrarchus labrax; European sea bass. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-5303.pdf |
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| Smith, Peter. |
| Some aspects of economic systems (eg, nonlinearity, qualitative variables) are intractable when incorporated into models. The widespread practice of excluding them (or greatly limiting their role) produces deviations of unknown size and form between the resulting models and the reality they purport to represent. To explore this issue, and the extent to which a change in methodology can improve tractability, a combination of two techniques, fuzzy logic and genetic algorithms, was applied to the problem of how the sellers in a freely competitive market, if initially trading at different prices, can find their way to supply/demand equilibrium. A multi-agent model was used to simulate the evolution of autonomously- learnt rule-governed behaviour, (i), under... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Competition; Markets; Walrasian Crier; Equilibrium; Fuzzy logic; Genetic algorithms; Evolutionary algorithms; Industrial Organization. |
| Ano: 2004 |
URL: http://purl.umn.edu/30569 |
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| Registros recuperados: 214 | |
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