946 resultados para temporal differences


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One potential source of heterogeneity within autism spectrum conditions (ASC) is language development and ability. In 80 high-functioning male adults with ASC, we tested if variations in developmental and current structural language are associated with current neuroanatomy. Groups with and without language delay differed behaviorally in early social reciprocity, current language, but not current autistic features. Language delay was associated with larger total gray matter (GM) volume, smaller relative volume at bilateral insula, ventral basal ganglia, and right superior, middle, and polar temporal structures, and larger relative volume at pons and medulla oblongata in adulthood. Despite this heterogeneity, those with and without language delay showed significant commonality in morphometric features when contrasted with matched neurotypical individuals (n = 57). In ASC, better current language was associated with increased GM volume in bilateral temporal pole, superior temporal regions, dorsolateral fronto-parietal and cerebellar structures, and increased white matter volume in distributed frontal and insular regions. Furthermore, current language–neuroanatomy correlation patterns were similar across subgroups with or without language delay. High-functioning adult males with ASC show neuroanatomical variations associated with both developmental and current language characteristics. This underscores the importance of including both developmental and current language as specifiers for ASC, to help clarify heterogeneity.

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Social behavior depends on the integrity of social brain circuitry. The temporal lobe is an important part of the social brain, and manifests morphological and functional alterations in autism spectrum disorders (ASD). Rats with temporal lobe epilepsy (TLE), induced with pilocarpine, were subjected to a social discrimination test that has been used to investigate potential animal models of ASD, and the results were compared with those for the control group. Rats with TLE exhibited fewer social behaviors than controls. No differences were observed in nonsocial behavior between groups. The results suggest an important role for the temporal lobe in regulating social behaviors. This animal model might be used to explore some questions about ASD pathophysiology. (c) 2008 Elsevier Inc. All rights reserved.

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Comparative studies on the reproductive biology of co-occurring related plant species have provided valuable information for the interpretation of ecological and evolutionary phenomena, with direct application in conservation management of plant populations. The aims of this thesis were to identify the causes of pre-dispersal reproductive losses in three Euphorbia species (the Mediterranean E. characias and the narrow endemics E. pedroi and E. welwitschii) and evaluate the variation of their effects in time, space and between individuals and species. Furthermore, we intended to study elaiosomes’ fatty acid profiles for the three Euphorbia and assess the role played by the elaiosome in ant attraction. Finally, we aimed to identify the major seed dispersal agents for each Euphorbia species in each site and study differences in short term seed fate due to differences in ant behaviour. The results indicated that intact seed production differed significantly between the three Euphorbia, mostly due to differences in cyathia production. Losses to pre-dispersal seed predators were proportionately larger for the endemic species which also suffered higher losses resulting in flower, fruit (in E. welwitschii) and seed abortion (in E. pedroi). The elaiosomes of E. pedroi are poor in fatty acids and for this reason seeds of this species were removed in lower proportion by mutualistic dispersers than those of their congeners, being more prone to seed predation. Two larger ant species – Aphaenogaster senilis and Formica subrufa – were responsible for a larger percentage of removals with seeds being transported at larger distances and being discarded in the vicinity of their nests following elaiosome removal. Our results highlight the role of insect-plant interactions as major determinants of seed survival for the three study plants and call for the need to include more information on insect-plant interactions in plant conservation programmes.

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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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We present a generic spatially explicit modeling framework to estimate carbon emissions from deforestation (INPE-EM). The framework incorporates the temporal dynamics related to the deforestation process and accounts for the biophysical and socioeconomic heterogeneity of the region under study. We build an emission model for the Brazilian Amazon combining annual maps of new clearings, four maps of biomass, and a set of alternative parameters based on the recent literature. The most important results are as follows: (a) Using different biomass maps leads to large differences in estimates of emission; for the entire region of the Brazilian Amazon in the last decade, emission estimates of primary forest deforestation range from 0.21 to 0.26 similar to Pg similar to C similar to yr-1. (b) Secondary vegetation growth presents a small impact on emission balance because of the short duration of secondary vegetation. In average, the balance is only 5% smaller than the primary forest deforestation emissions. (c) Deforestation rates decreased significantly in the Brazilian Amazon in recent years, from 27 similar to Mkm2 in 2004 to 7 similar to Mkm2 in 2010. INPE-EM process-based estimates reflect this decrease even though the agricultural frontier is moving to areas of higher biomass. The decrease is slower than a non-process instantaneous model would estimate as it considers residual emissions (slash, wood products, and secondary vegetation). The average balance, considering all biomass, decreases from 0.28 in 2004 to 0.15 similar to Pg similar to C similar to yr-1 in 2009; the non-process model estimates a decrease from 0.33 to 0.10 similar to Pg similar to C similar to yr-1. We conclude that the INPE-EM is a powerful tool for representing deforestation-driven carbon emissions. Biomass estimates are still the largest source of uncertainty in the effective use of this type of model for informing mechanisms such as REDD+. The results also indicate that efforts to reduce emissions should focus not only on controlling primary forest deforestation but also on creating incentives for the restoration of secondary forests.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Recursos pesqueiros são importantes fontes de renda e alimento para as populações rurais e urbanas na Amazônia. O presente trabalho avalia a pesca e as variáveis ambientais que determinam a produção de pescarias que desembarcam em Manaus, e avalia também a abundância relativa de recursos pesqueiros em diferentes subsistemas na Amazônia Central. A informação coletada no porto de desembarque de pescado de Manaus foi utilizada para testar um novo índice de captura obtido a partir de um modelo de covariância que apresentou as seguintes variáveis significativas: número de pescadores/dia (dias de pesca vezes número de pescadores por viagem); distância do pesqueiro até Manaus; quantidade de gelo que usou durante a viagem; e nível de rio. Não houve nenhuma diferença significativa entre valores médios de captura entre os subsistemas do Purus, Madeira e de Juruá. Estes resultados sugerem que os tributários da margem direita são similares e mais produtivos em termos comerciais. Concluiu-se que a produção corrente varia de acordo com a magnitude de esforço pesqueiro, por variações ambientais, assim como por aspectos operacionais da pesca, particularmente o consumo de gelo.

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A variação espacial e temporal de rotíferos foi analisada em um reservatório pequeno, raso e eutrófico, com intensas florações de algas Cyanobacteria, em sete pontos de amostragem durante 17 meses (março/2002 a julho/2003). Foram identificados 52 táxons em 16 famílias, sendo Brachionidade, Conochilidae, Synchaetidae, Lecanidae, Collothecidae, Trichocercidae e Gastropodidae as mais frequentes. Collotheca sp. foi abundante no inverno (período seco), enquanto Conochilus coenobasis Skorikov, 1914 e Keratella cochlearis Gosse, 1851 apresentaram baixas abundâncias. Brachionus mirus var. reductus (Koste, 1972), Filinia longiseta (Ehrenberg, 1834) e Keratella lenzi (Hauer, 1953) apresentaram picos de abundância no verão (período chuvoso), e Kellicottia bostonensis (Rousselet, 1908), Ploesoma truncatum (Levander, 1894), Polyarthra remata (Skorikov, 1896), Polyarthra vulgaris Carlin, 1943 e Ptygura sp. no inverno, entretanto, relacionados a chuvas atípicas. Diferenças significativas do número de táxons e da abundância total dos rotíferos ocorreram entre os meses amostrados. A análise de correspondência canônica explicou 46% da relação da abundância dos rotíferos e variáveis ambientais, correlacionados com a pluviosidade, nitrito, temperatura da água, nitrogênio orgânico, nitrato e temperatura do ar. Houve flutuações na abundância dos rotíferos um mês após oscilações na abundância do fitoplâncton. A maior parte das correlações entre as abundâncias de espécies de rotíferos e do fitoplâncton foi positiva. Alguns táxons como Filinia longiseta, Keratella lenzi e K. cochlearis apresentaram variação temporal definida e semelhante a outros reservatórios eutróficos. A ausência de padrões claros de distribuição em algumas espécies foi atribuída a hidrodinâmica do reservatório, o qual foi construído recentemente, e as condições climáticas adversas durante o período de estudo, como as chuvas intensas no inverno.

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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Abundance and ecological distribution of the rock shrimp Sicyonia dorsalis from the northern coast of São Paulo State (Brazil) was investigated during a two-year period (July 2001 to June 2003). Monthly collections were conducted in the Ubatuba (UBA) and Caraguatatuba (CA) regions, using a commercial shrimp boat equipped with double-rig nets. In each region, seven depths were delimited (5 m to 35 m). A total of 1,752 and 1,894 shrimp were obtained at UBA and CA, respectively. The distribution of S. dorsalis differed among depths, years, and seasons. Highest abundance values were recorded in depths where silt and clay comprised more than 70% of the sediment. The majority (89%) of captured specimens were caught in the first year, in periods of lower mean temperature, mainly in the spring of 2001, when the intrusion of cold South Atlantic Central Waters (SACW) was more intense. In such period, the differences in the abundance of shrimps in each region (UBA = 1,118 and CA = 493) suggested that S. dorsalis migrated to the north (UBA), during the SACW intrusion. Thus, sediment type and water temperature are among the most important variables affecting the bathymetric distribution of S. dorsalis in these regions.

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PURPOSE--To analyze the influence of transient and sustained elevations of arterial pressure (AP) on the rate of rise of the left ventricular pressure (dp/dt). METHODS--Thirteen anesthetized, thoracotomized and mechanically ventilated dogs, submitted to pharmacological autonomic block (oxprenolol-3 mg/kg plus atropine-0.5 mg/kg). The AP elevation was obtained by mechanical constriction of the descending thoracic aorta. Two protocols were applied to all animals: Transient Arterial Hypertension (TAH) and Sustained Arterial Hypertension (SAH) and the following variables were evaluated: heart rate (HR), systolic (LVSP) and end diastolic (LVEDP) left ventricular pressure and dp/dt. In TAH the variables were analyzed in the basal condition (To) and at the maximal value of AP attained during the transient pressure elevation (TM). In the protocol SAH the variables were evaluated in the conditions: Control (Ho), hypertension 1 (H1) and hypertension 2 (H2). RESULTS--Considering all conditions, there were no significant differences among the values of HR. In the protocol TAH, the LVSP varied from 133 +/- 22 mmHg to 180 +/- 27 mmHg, whereas in SAH the values of LVSP were as follow: HO = 129 +/- 25 mmHg; H1 = 152 = 23 mmHg; H2 = 182 +/- 24 mmHg. LVEDP changed in both protocols: To = 7 +/- 2 mmHg; TM = 13 +/- 2 mmHg (p < 0.05); Ho = 7 +/- 2 mmHg; H1 = 10 +/- 2 mmHg; H2 = 14 +/- 3 mmHg (p < 0.05). During TAH there was no difference between the values of dp/dt (To = 3.303 +/- 598 mmHg/s; TM = 3.350 +/- 653 mmHg/s; p > 0.05), however, there were increases of the dp/dt during SAH (Ho = 3.233 +/- 576 mmHg/s; H1 = 3.831 +/- 667 mmHg/s; H1 = 4.594 +/- 833 mmHg/2; p < 0.05). CONCLUSION--The values of dp/dt are not influenced by transient elevation of AP. Sustained increase of AP activates cardiac adjustments, which results in elevation of dp/dt, by stimulation of contractile state. Probably, the inotropic intervention mechanism is the length dependent activation due to the Frank-Starling mechanism.