843 resultados para Competition intensity
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The effect of competition is an important source of variation in breeding experiments. This study aimed to compare the selection of plants of open-pollinated families of Eucalyptus with and without the use of competition covariables. Genetic values were determined for each family and tree and for the traits height, diameter at breast height and timber volume in a randomized block design, resulting in the variance components, genetic parameters, selection gains, effective size and selection coincidence, with and without the use of covariables. Intergenotypic competition is an important factor of environmental variation. The use of competition covariables generally reduces the estimates of variance components and influences genetic gains in the studied traits. Intergenotypic competition biases the selection of open-pollinated eucalypt progenies, and can result in an erroneous choice of superior genotypes; the inclusion of covariables in the model reduces this influence.
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O presente estudo teve como objetivo comparar os níveis plasmáticos de glicose e cortisol de um grupo de eqüinos atletas submetidos ao esforço de longa duração (enduro eqüestre) em distâncias de 30 e 60km, com velocidades médias de 10 e 15km h-1, respectivamente. Os animais foram aleatoriamente separados em dois grupos, sendo que a um deles foi administrada, por via oral, uma pasta eletrolítica hipertônica antes, durante e após as referidas provas. O outro grupo foi usado como controle. Os resultados das concentrações de cortisol revelaram um aumento significativo, no primeiro momento, em que a intensidade do esforço era maior (15km/h), ou com a continuação deste (30km de distância), no segundo momento, para todos os grupos. Os resultados referentes à concentração de glicose permaneceram constantes durante a prova de 30km; entretanto, nos primeiros 20km da prova de 60km, tais resultados revelaram um aumento significativo no grupo controle, retornando a valores basais no momento subseqüente. A reposição eletrolítica tem a sua importância na manutenção do equilíbrio hidroeletrolítico e ácido básico e, no presente estudo, pode ter contribuído para a manutenção da concentração média de glicose plasmática.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This research aimed to study competition effects of legumes intercropping and weeds on seeds yield and quality of Sorghum bicolor (L.) Moench. The experiment was carried out in a Rhodic Nitisol, under field condition in Botucatu region, São Paulo State, Brazil. Ten treatments were tested: sorghum (cv. A-6304) intercropped with Dolichos lablab L., Mucuna aterrima (Piper et Tracy) Holland, Canavalia ensiformis D. C. or Crotalaria juncea L., that were sown in the same time of sorghum or 20 days after the sorghum sowing, and sorghum weed-free and sorghum without weeding. The experimental design employed was the completely randomized blocks with four replications. There were evaluated sorghum seeds yield and some characteristcs of seed quality: purity, hectolitric weight, 1000 seeds weight, insect infestation, germination and vigor (by first counting of germination test and accelerated ageing test). The competition caused by legumes intercropping and weeds affected the yield and the physical and physiological characteristics of sorghum seeds, but the intensity of prejudicial effects depended on the time and the species of legume intercropping.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The aim of this study was to investigate the potential relationship between excess post-exercise oxygen consumption (EPOC), heart rate recovery (HRR) and their respective time constants (tvo(2) and t(HR)) and body composition and aerobic fitness (VO(2)max) variables after an anaerobic effort. 14 professional cyclists (age = 28.4 +/- 4.8 years, height = 176.0 +/- 6.7 cm, body mass = 74.4 +/- 8.1 kg, VO(2)max = 66.8 +/- 7.6 mL. kg(-1) . min(-1)) were recruited. Each athlete made 3 visits to the laboratory with 24h between each visit. During the first visit, a total and segmental body composition assessment was carried out. During the second, the athletes undertook an incremental test to determine VO(2)max. In the final visit, EPOC (15-min) and HRR were measured after an all-out 30s Wingate test. The results showed that EPOC is positively associated with % body fat (r = 0.64), total body fat (r = 0.73), fat-free mass (r = 0.61) and lower limb fat-free mass (r = 0.55) and negatively associated with HRR (r = - 0.53, p < 0.05 for all). HRR had a significant negative correlation with total body fat and % body fat (r = - 0.62, r = - 0.56 respectively, p < 0.05 for all). These findings indicate that VO(2)max does not influence HRR or EPOC after high-intensity exercise. Even in short-term exercise, the major metabolic disturbance due to higher muscle mass and total muscle mass may increase EPOC. However, body fat impedes HRR and delays recovery of oxygen consumption after effort in highly trained athletes.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Food access, territory or reproductive partner can generate conflicts between individuals in many species with occurrence of aggressive behaviors. However some species respond less aggressively to intrusion by neighbors than non-neighbors in its territory to minimize the costs of continuous fight. This difference in aggression is called Dear Enemy Effect described in various vertebrates and invertebrates. To investigate if this phenomenon occurs in Dinoponera quadriceps (Hymenopetra, Formicidae) three colonies, two neighbors and one non-neighbor, were captured in its natural environment then transfered to the laboratory where we did experimental confrontation intra and inter colonies involving one pair of workers. We compared the behavioral frequency exhibited by each worker, the intensity and duration of the confrontation between a neighbor and a non-neighbor referring the place where they were collected. Our results revealed that Dear Enemy Effect does not apply to D. quadriceps due aggressive response is more intense and longest toward neighbor than non-neighbor, probably due intra specific competition, ecological factors and characteristic of the species
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The group Callithrichidae is characterized by the flexibility in its mating system. This fact generates questions about the mechanisms that Callithrix jacchus males reach the breeding position in a group and how they prevent the subordinates reproduction, since the competition apparently happens with less intensity when compared to the females. Studies have shown the importance of social interactions and kinship among individuals in the distribution of mating opportunities in a group. This work aimed to evaluate if dyads of Callithrix jacchus males acted socially different due to kinship. We observed the agonistic and affiliative behaviours made by the males when associated in dyads (Phase 1) and when these dyads received a female (Phase 2), which was introduced in the pair`s cage for 45 minutes. In the phase 2, we also accounted for the sexual interactions between males and female in each trio. We used 16 males, 8 related (brothers-R) and 8 nonrelated (NR), as well as 8 females. Each phase lasted 4 weeks, with 3 observations/week, during 15 min/male in phase 1 and 2. In the first phase, two pairs of R males had a contested dominance and the other two, just like in the NR males, had an uncontested dominance. The NR dominant males were more aggressive than the subordinates. With the female`s entrance in the cage, all male pairs began to have an uncontested dominance. The NR males aggression frequency rose along with the subordinates` submission. In the R males, the frequency of grooming and physical contact was higher than in the NR males. So, we conclude that the low levels of agonism presented by the R males, along with the higher tolerance shown amongst them, lead us to believe that kinship attenuate the competition among these males
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A detector system that can measure X-ray intensity in the mammographic range of 22 to 36 kVp (equivalent photon energies ofthe beam between 11 and 15 keV) is presented. It consists of a lithium mobate detector and a high-sensitivity current-to-voltage converter.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Aim. One of the major causes of chronic venous disease is venous reflux, the identification and quantification of which are important for diagnosis. Duplex scanning allows for the detection and quantification of reflux in individual veins. Evaluation of the great saphenous vein in primary varicosis is necessary for its preservation. Objective of the study is to evaluate a possible correlation between the intensity of reflux at the saphenofemoral junction, diameter alterations of the incompetent great saphenous vein and the practical effect of such correlation. Also to compare the clinical severity of the CEAP classification with such parameters.Methods. Three hundred limbs were submitted to duplex evaluation of their insufficient saphenous veins. Vein diameter was measured on five different points. Velocity and flow at reflux peak and reflux time were determined. The saphenous vein's diameters were correlated with velocity, flow and time. The three latter parameters and diameters were compared with clinical severity according to CEAP.Results. Correlation was found between the saphenous vein's diameters, velocity and flow. No correlation was observed between time and diameter in the thigh's upper and middle thirds. When comparing diameter, velocity and flow with CEAP clinical severity classification, an association was observed. The correlation between reflux time with clinical severity was weak.Conclusion. Reflux time is a good parameter for identifying the presence of reflux, but not for quantifying it. Velocity and peak flow were better parameters for evaluating reflux intensity as they were correlated with great saphenous vein alterations, and were associated with the disease's clinical severity. [Int Angiol 2010;29:323-30]
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)