942 resultados para last copy
Functional Redundancy and Complementarities of Seed Dispersal by the Last Neotropical Megafrugivores
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Background: Functional redundancy has been debated largely in ecology and conservation, yet we lack detailed empirical studies on the roles of functionally similar species in ecosystem function. Large bodied frugivores may disperse similar plant species and have strong impact on plant recruitment in tropical forests. The two largest frugivores in the neotropics, tapirs (Tapirus terrestris) and muriquis (Brachyteles arachnoides) are potential candidates for functional redundancy on seed dispersal effectiveness. Here we provide a comparison of the quantitative, qualitative and spatial effects on seed dispersal by these megafrugivores in a continuous Brazilian Atlantic forest. Methodology/Principal Findings: We found a low overlap of plant species dispersed by both muriquis and tapirs. A group of 35 muriquis occupied an area of 850 ha and dispersed 5 times more plant species, and 13 times more seeds than 22 tapirs living in the same area. Muriquis dispersed 2.4 times more seeds in any random position than tapirs. This can be explained mainly because seed deposition by muriquis leaves less empty space than tapirs. However, tapirs are able to disperse larger seeds than muriquis and move them into sites not reached by primates, such as large forest gaps, open areas and fragments nearby. Based on published information we found 302 plant species that are dispersed by at least one of these megafrugivores in the Brazilian Atlantic forest. Conclusions/Significance: Our study showed that both megafrugivores play complementary rather than redundant roles as seed dispersers. Although tapirs disperse fewer seeds and species than muriquis, they disperse larger-seeded species and in places not used by primates. The selective extinction of these megafrugivores will change the spatial seed rain they generate and may have negative effects on the recruitment of several plant species, particularly those with large seeds that have muriquis and tapirs as the last living seed dispersers. © 2013 Bueno et al.
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Includes bibliography
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The stride before landing may be important during stepping down. The aim of this study was to analyze variability of the kinematics and muscle activity in the final stride before stepping down a curb, with and without ankle and knee muscle fatigue. Ten young participants walked at self-selected speed and stepped down a height difference (10-cm) in ongoing gait. Five trials were performed before and after a muscle fatigue protocol (one day: ankle muscle fatigue, another day: knee muscle fatigue). The analysis focused on the trailing leg during the last but one and the last step on the higher level. Kinematics and muscle activity were recorded. Fatigue increased variability of foot-step horizontal distance in the last step on the higher level of the trailing limb, as well as in the first steps on the lower level for both limbs. This appeared due to an increase in the range of motion of the knee joint after both fatigue protocols. Participants additionally showed an increased ankle and hip ROM and decreased knee ROM. Our results suggest a loss of control under fatigue reflected in a higher variability of trailing and leading limb-step horizontal distances, with compensatory changes to limit fatigue effects, such as a redistribution of movement over joints. © 2012 Elsevier B.V.
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In most studies on beef cattle longevity, only the cows reaching a given number of calvings by a specific age are considered in the analyses. With the aim of evaluating all cows with productive life in herds, taking into consideration the different forms of management on each farm, it was proposed to measure cow longevity from age at last calving (ALC), that is, the most recent calving registered in the files. The objective was to characterize this trait in order to study the longevity of Nellore cattle, using the Kaplan-Meier estimators and the Cox model. The covariables and class effects considered in the models were age at first calving (AFC), year and season of birth of the cow and farm. The variable studied (ALC) was classified as presenting complete information (uncensored = 1) or incomplete information (censored = 0), using the criterion of the difference between the date of each cow's last calving and the date of the latest calving at each farm. If this difference was >36 months, the cow was considered to have failed. If not, this cow was censored, thus indicating that future calving remained possible for this cow. The records of 11 791 animals from 22 farms within the Nellore Breed Genetic Improvement Program ('Nellore Brazil') were used. In the estimation process using the Kaplan-Meier model, the variable of AFC was classified into three age groups. In individual analyses, the log-rank test and the Wilcoxon test in the Kaplan-Meier model showed that all covariables and class effects had significant effects (P < 0.05) on ALC. In the analysis considering all covariables and class effects, using the Wald test in the Cox model, only the season of birth of the cow was not significant for ALC (P > 0.05). This analysis indicated that each month added to AFC diminished the risk of the cow's failure in the herd by 2%. Nonetheless, this does not imply that animals with younger AFC had less profitability. Cows with greater numbers of calvings were more precocious than those with fewer calvings. Copyright © The Animal Consortium 2012.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Comunicação - FAAC
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Histórias infantis têm sido utilizadas como recurso lúdico-didático na instalação de comportamentos. Nesta literatura, estes comportamentos geralmente estão descritos na forma de regras de conduta, explícitas (regras prescritivas) ou implicitamente (regras descritivas). O presente estudo avaliou o efeito da exposição continuada a histórias infantis, sobre a frequência e o tempo de engajamento em comportamentos relevantes à aprendizagem escolar, de quatro crianças entre sete e oito anos. Foram realizadas entrevistas semi-estruturadas com as professoras objetivando coletar relatos sobre o desempenho de seus alunos em atividades escolares. Em seguida, o experimentador realizou registros cursivos dos comportamentos das crianças em situação de sala de aula, com o objetivo de identificar a ocorrência e a freqüência dos comportamentos relatados pela professora, para selecionar e categorizar os comportamentos alvos. Foram selecionados os comportamentos de Cópia, Responder e Visto, a partir de então foram realizados registros de ocorrências da emissão destes comportamentos, com o objetivo de ter uma linha de base da freqüência de emissão destes comportamentos. A Condição Experimental era composta de linha de base e seis fases, em cada fase eram lidas histórias diferentes. A Fase sempre era iniciada com a leitura de uma história, seguida do registro de ocorrências dos comportamentos alvos. As histórias apresentavam regras descritivas mostrando as conseqüências positivas da emissão dos comportamentos selecionados e as conseqüências negativas da emissão de comportamentos incompatíveis com os mesmos. Os resultados sugerem que a exposição continuada às histórias foram eficientes para instalar e ou aumentar a frequência dos comportamentos de Cópia, Responder e Visto, bem como o tempo de engajamento das crianças nestas atividades.
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Land cover change in the Neotropics represents one of the major drivers of global environmental change. Several models have been proposed to explore future trajectories of land use and cover change, particularly in the Amazon. Despite the remarkable development of these tools, model results are still surrounded by uncertainties. None of the model projections available in the literature plausibly captured the overall trajectory of land use and cover change that has been observed in the Amazon over the last decade. In this context, this study aims to review and analyze the general structure of the land use models that have most recently been used to explore land use change in the Amazon, seeking to investigate methodological factors that could explain the divergence between the observed and projected rates, paying special attention to the land demand calculations. Based on this review, the primary limitations inherent to this type of model and the extent to which these limitations can affect the consistency of the projections will also be analyzed. Finally, we discuss potential drivers that could have influenced the recent dynamic of the land use system in the Amazon and produced the unforeseen land cover change trajectory observed in this period. In a complementary way, the primary challenges of the new generation of land use models for the Amazon are synthesized. (c) 2014 Elsevier Ltd. All rights reserved.
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Pós-graduação em Medicina Veterinária - FMVZ
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The agrarian reform allows for land redistribution and gives rural workers the opportunity to develop their life projects, rescuing the dignity of a historically excluded population. The conquest of the land carries significances that span from the rescue of citizenship to the improvement of living conditions due to the acquisition of goods, products and services. It is pointed out that in Brazil there still exists a marked concentration of large-landed estates. In this sense, this work had the objective of analyzing the Brazilian agrarian reform process during the last two decades. In this period the country had three Presidents, two of them elected with the support of the Rural Landless Workers Movement, increasing the expectations in relation to the fulfillment of the agrarian reform. The advances in the policies of rural settlements are notable; however, the structure of large-land estates remains unaltered. In the last two years (2011 and 2012) the number of settled families, as well as the number of settlements accomplished, were the worst since 2006. The priority of the current government is the eradication of extreme poverty and, in this sense, the agrarian reform becomes an essential policy to contribute to such goal, since with the distribution of the property of the land also diminishes the concentration of wealth.
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A polimicrogiria (PMG) é uma malformação do córtex cerebral causada por falhas no seu desenvolvimento, caracterizando-se por um número excessivo de pequenos giros e laminação anormal, dando à superfície cortical uma aparência irregular e grosseira. A gravidade de suas manifestações clínicas se relaciona diretamente com a extensão da malformação e das regiões cerebrais afetadas, sendo que a presença de lesões bilaterais ou unilaterais extensas indica um pior prognóstico. Uma das síndromes de polimicrogiria mais freqüentes e, conseqüentemente, mais bem descritas clinicamente, é a polimicrogiria perisylviana bilateral (PPB). Essa forma de PMG atinge a região que tange a fenda Sylviana, podendo apresentar-se tanto unilateralmente quanto em ambos os hemisférios. Vários genes têm sido relacionados a diferentes formas de polimicrogiria, são eles AFF2,TUBA1A, TUBB2B e TUBA8, SRPX2 e WDR62. Estes genes já foram estudados pelo nosso grupo de pesquisa em um grupo de pacientes compostos de casos familiares e esporádicos, acometidos em sua maioria pela forma perisylviana de PMG. Nenhuma variante deletéria foi identificada nestes genes. Recentemente um novo gene foi implicado na etiologia molecular das PMG, o TUBB3. O gene em questão pertence à mesma família de TUBA1A, TUBB2B e TUBA8 e codifica uma proteína de ligação aos microtúbulos, tendo importante papel na formação do fuso. Além deste gene, também tem sido descritas alterações genômicas, denominadas de Copy Number Variations (CNV), estas variações estruturais tem sido associadas com diversos distúrbios neurológicos, que vão desde transtornos psiquiátricos até malformações do córtex cerebral como a PMG. Desta forma, o objetivo deste trabalho foi analisar a existência de alterações de ponto deletérias no gene TUBB3 em pacientes com PMG e também, o envolvimento de CNVsna etiologia deste tipo de malformação ...
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In the first decades of the last century, Brazilian intellectuals played an im- portant role in the new configuration to the country reached. Brazil had then passed by rapid process of moderniza- tion. The educational field was place of contention between different currents of intellectuals. The idea was to create a new society through what is called the New School. In Brazil, unlike in Europe, most of the population had no access to school. Therefore, the New School was not privileged to critique existing school system, but the actual construction of the large Brazilian childhood schooling. Thus, we crea- ted libraries in teaching urban school groups, with the aim of improving the training of primary school teachers in the pedagogical ideas of the New School. This work has for objective to understand the conflicts among Brazi- lian intellectuals on the list of recommended readings for teacher training schools in the first half of the twentieth century. This paper presents an exam- ple of this intellectual dispute through the analysis of a Brazilian school li- brary copy of the 1930s.