922 resultados para 54301-023
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Larval development of Macrocoeloma diplacanthum (Stimpson) consists of two zoeal stages, followed by the megalopa. Each larval stage is described in detail. The duration of the zoeal stages was 2-3 (2.4 +/- 0.5) and 3-4 (3.5 +/- 0.5) days for the first and second zoea, respectively, the megalopa phase appearing 6-8 (7.0 +/- 0.5) days after hatching. Unlike for other majids, zoeal stages of M. diplacanthum can be readily distinguished by their distended forehead with strong underlying muscle bands, undercut dorsal carapace spine, and spine on the terminal endopod segment of the first maxilliped. No other known mithracine or majid zoeae exhibit this combination of features. Our zoeal account of M. diplacanthum from Mexico is remarkably consistent with Floridian specimens previously described. However, we have found some differences between descriptions, which could be attributed to natural variation or inadequate description. Previous attempts to evaluate the relationships within Mithacinae have been based on larval characters widely distributed throughout Majidae and therefore are considered inadequate to infer sister-group relationships. The phylogenetic analysis of majids suggested that the position of Mithracinae is still uncertain, as is its monophyletic status. We recommend that additional characters, particularly of the megalopa phase, be sought for a better resolution of majid evolutionary history.
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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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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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Determining the genetic structure of tropical bird populations is important for assessing potential genetic effects of future habitat fragmentation and for testing hypotheses about evolutionary mechanisms promoting diversification. Here we used 10 microsatellite DNA loci to describe levels of genetic differentiation for five populations of the lek-mating blue manakin (Chiroxiphia caudata), sampled along a 414-km transect within the largest remaining continuous tract of the highly endangered Atlantic Forest habitat in southeast Brazil. We found small but significant levels of differentiation between most populations. F-ST values varied from 0.0 to 0.023 (overall F-ST = 0.012) that conformed to a strong isolation by distance relationship, suggesting that observed levels of differentiation are a result of migration-drift equilibrium. N(e)m values estimated using a coalescent-based method were small (<= 2 migrants per generation) and close to the minimum level required to maintain genetic similarity between populations. An implication of these results is that if future habitat fragmentation reduces dispersal between populations to even a small extent, then individual populations may undergo a loss of genetic diversity due to an increase in the relative importance of drift, since inbreeding effective population sizes are relatively small (N-e similar to 1000). Our findings also demonstrate that population structuring can occur in a tropical bird in continuous habitat in the absence of geographical barriers possibly due to behavioural features of the species.
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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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In the Pantanal wetlands of Central Brazil, the endangered hyacinth macaw (Anodorhynchus hyacinthinus), the largest psitacid in the world, makes its nest almost exclusively in natural hollows found in the manduvi tree (Sterculia apetala). The recruitment of manduvis greatly depends on the seed dispersal services provided by the toco toucan (Ramphastos toco), responsible for 83.3% of the seed dispersal. The toco toucan, however, is responsible for about 53% of the preyed eggs, resulting in a case of conflicting ecological pressures in which the reproduction of the hyacinth macaw is indirectly dependent on the seed dispersal services of its nest predator. The case illustrates the intricacies of biotic interactions in species-rich environments where species may be tied by indirect, subtle ecological links which conservationists should be aware of. (c) 2008 Elsevier Ltd. All rights reserved.
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Background: Determinants of public healthcare expenditures in type 2 diabetics are not well investigated in developing nations and, therefore, it is not clear if higher physical activity decreases healthcare costs. The purpose of this study was to analyze the relationship between physical activity and the expenditures in public healthcare on type 2 diabetes mellitus treatment.Methods: Cross-sectional study carried out in Brazil. A total of 121 type 2 diabetics attended to in two Basic Healthcare Units were evaluated. Public healthcare expenditures in the last year were estimated using a specific standard table. Also evaluated were: socio-demographic variables; chronological age; exogenous insulin use; smoking habits; fasting glucose test; diabetic neuropathy and anthropometric measures. Habitual physical activity was assessed by questionnaire.Results: Age (r = 0.20; p = 0.023), body mass index (r = 0.33; p = 0.001) and waist-to-hip ratio (r = 0.20; p = 0.025) were positively related to expenditures on medication for the treatment of diseases other than diabetes. Insulin use was associated with increased expenditures. Higher physical activity was associated with lower expenditure, provided medication for treatment of diseases other than diabetes (OR = 0.19; p = 0.007) and medical consultations (OR = 0.26; p = 0.029).Conclusions: Type 2 diabetics with higher enrollment in physical activity presented consistently lower healthcare expenditures for the public healthcare system.
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Background: Hyperhomocysteinemia is a major risk factor for cerebral and peripheral vascular diseases, as well as cortical and hippocampal injury, including an increased risk of dementia and cognitive impairment. Elevated serum homocysteine (Hcy) concentrations are common in patients with Parkinson's disease (PD) who have been treated with levodopa; however, physical exercises can help reduce Hcy concentrations. The aim of the present study was to compare serum Hcy levels in patients with PD who partook in regular physical exercises, sedentary PD patients, and healthy controls.Methods: Sixty individuals were enrolled in the present study across three groups: (i) 17 patients who did not partake of any type of exercise; (ii) 24 PD patients who exercised regularly; and (iii) 19 healthy individuals who did not exercise regularly. All participants were evaluated by Hoehn and Yahr scale, the Unified Parkinson's Disease Rating Scale (UPDRS) and Schwab and England scale (measure daily functionality). The serum levels of Hcy were analyzed by blood samples collected of each participant. An analysis of variance and a Tukey's post hoc test were applied to compare and to verify differences between groups. Pearson's correlation and stepwise multiple regression analyses were used to consider the association between several variables.Results: Mean plasma Hcy concentrations in individuals who exercised regularly were similar to those in the healthy controls and significantly lower than those in the group that did not exercise at all (P = 0.000). In addition, patients who did not exercise were receiving significantly higher doses of levodopa than those patients who exercised regularly (P = 0.001). A positive relationship between levodopa dose and Hcy concentrations (R(2) = 0.27; P = 0.03) was observed in patients who did not exercise, but not in those patients who exercised regularly (R(2) = 0.023; P = 0.15).Conclusions: The results of the present study suggest that, even with regular levodopa therapy, Hcy concentrations in PD patients who exercise regularly are significantly lower than in patients who do not exercise and are similar Hcy concentrations in healthy controls.
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Using the exclusive decay B-s(0)-->J/psi(mu(+)mu(-))phi(K+K-), we report the most precise single measurement of the B-s(0) lifetime. The data sample corresponds to an integrated luminosity of approximately 220 pb(-1) collected with the D0 detector at the Fermilab Tevatron Collider in 2002-2004. We reconstruct 337 signal candidates, from which we extract the B-s(0) lifetime, tau(B-s(0))=1.444(-0.090)(+0.098)(stat)+/-0.020(sys) ps. We also report a measurement for the lifetime of the B-0 meson using the exclusive decay B-0-->J/psi(mu(+)mu(-))K-*0(892)(K(+)pi(-)). We reconstruct 1370 signal candidates, obtaining tau(B-0)=1.473(-0.050)(+0.052)(stat)+/-0.023(sys) ps, and the ratio of lifetimes, tau(B-s(0))/tau(B-0)=0.980(-0.071)(+0.076)(stat)+/-0.003(sys).
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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In covariant gauges (CG) regularized with dimensional regularization (DR) it is a standard procedure to set all tadpole Feynman integrals to zero, though; explicitly, they diverge quadratically as the space-time volume. on the other hand, in the notoriously subtle light-front gauge (LTG) some divergent tadpole integrals are said to be nonvanishing, i.e., cannot be set to zero as in the CC case. In this article we analyse the reasons behind this seemingly ambiguous results.