1,720,959 research outputs found
The forest transition in São Paulo, Brazil: drivers related to forest loss and recovery
No full textSegundo a Teoria da Transição Florestal, países menos desenvolvidos teriam altas taxas de desmatamento, pois a economia destes países é baseada no desenvolvimento e expansão agrícola. Com o avanço do desenvolvimento econômico a industrialização, urbanização e a modernização do uso da terra levariam ao abandono de terras menos adequadas à agricultura que seriam ativamente reflorestadas ou regenerariam. Visto que São Paulo vem apresentando ganhos de cobertura florestal nativa, este estudo teve como objetivo principal identificar os fatores relacionados ao processo de transição florestal no estado de São Paulo entre 1960 e 2006. Para isso, o Capítulo 1 avaliou as discrepâncias entre três estimativas de cobertura florestal nativa disponíveis para o estado de São Paulo (censo agropecuário e dois mapeamentos com resolução de 10m e 30m), em escala municipal, e as possíveis fontes de viés associadas aos métodos de coleta. O Capítulo 2 identificou os fatores socioeconômicos e biofísicos associados ao desmatamento e à recuperação das florestas nativas nos municípios do estado de São Paulo em quatro períodos consecutivos (1960-1970, 1970-1980, 1980-1996, 1996-2006). Os resultados do Capítulo 1mostraram que o censo agropecuário subestima a cobertura florestal quando há áreas protegidas nos municípios. Mapas com resolução de 30m também subestimam a cobertura florestal nativa em relação aos mapas com 10m de resolução, visto que não detectam pequenos fragmentos. As três fontes de dados são congruentes, porém os vieses relacionados aos métodos podem refletir nos resultados. Logo, a escolha dos dados deve ser feita de acordo com os objetivos do estudo a ser desenvolvido e considerando os métodos de coleta e possíveis fontes de viés de cada conjunto de dados. O Capítulo 2 mostrou que as perdas de florestas ocorreram principalmente em municípios com solos mais úmidos e/ou naqueles em que houve expansão de cultivos. Enquanto ganhos de florestas ocorreram principalmente em municípios com maior cobertura florestal, maior declividade média, que empregaram maior número de trabalhadores permanentes e usaram mais fertilizantes. Estes resultados mostram que, entre 1960 e 2006, a expansão do uso da terra levou a perdas de florestas em áreas mais adequadas à agricultura de São Paulo. Com o tempo, porém, fatores que aumentam a produtividade ou reduzem a conversão de áreas naturais levaram ao aumento de florestas, principalmente em terras menos adequadas à agricultura. Tais fatores, no entanto, foram influenciados por políticas governamentais para modernização da agricultura e proteção dos ecossistemas naturais, e pela pressão do mercado externo por certificação ambiental. Estes resultados enfatizam a necessidade de se considerar, em conjunto, desenvolvimento da agricultura e conservação do meio ambiente para o desenvolvimento de políticas de uso da terra mais eficientesAccording to Forest Transition Theory, less developed countries or regions present high rates of deforestation because their economy is based on agricultural development and agriculture expansion. As the economy develops industrialization, urbanization and agriculture modernization lead to the abandonment of lands less suitable for agriculture which are reforested or regenerate spontaneously. Since forest cover of São Paulo has increased, this study aimed to identify the socioeconomic and biophysical factors related to forest transition in the state of São Paulo between 1960 and 2006. For this purpose, Chapter 1 evaluate the discrepancies among three free datasets of São Paulo\'s forest cover (agricultural census, maps at 10m and 30m resolution), in municipality-scale, and the possible sources of bias. Chapter 2 identified the factors related to deforestation and forest gains in São Paulo\'s municipalities during four consecutive intervals (1960-1970, 1970-1980, 1980-1996, 1996-2006). Chapter 1 showed that census underestimate forest cover when legally protected areas are present, reflecting the limitation of survey methods in rural properties. Maps at 30m resolution also underestimate forest cover in comparison to maps at 10m resolution, since 30m resolution cannot detect small and narrow patches. The three datasets are congruent, but the results indicate that bias related to methods can affect analysis results. Therefore, users should choose a dataset according to aims of the study and considering the sources of bias in the data. Chapter 2 showed that forest losses were greater in municipalities with moist soils and large tracts of agricultural lands, while forest gains were higher in municipalities with high forest cover and steep slopes, and that employed a large number of permanent workers and relied on high fertilizer input. Between 1960 and 2006, land use expansion led to forest losses in more suitable areas for agriculture in São Paulo. Over time, factors that increase productivity or reduce pressure on land development led to forest gains mainly in less suitable lands. These proximate factors, however, were driven by underlying factors as governmental policies to modernize agriculture and protect natural ecosystems, and by external market demands for environmental certification. These results highlight the need to jointly consider agricultural development and environmental conservation policies for the development of effective land use policie
Distribution and abundance of small mammals in an early growth silvicultural landscape in Paranapanema basin, São Paulo, Brazil
No full textO cultivo florestal do eucalipto foi introduzido no Brasil no início do século XX com o intuito de suprir de matéria prima as fornalhas e ferrovias em construção na época. A produção é destinada para os mais diversos propósitos e está ainda em ascensão, de tal forma que a área plantada ocupa atualmente mais de quatro milhões de hectares no país. Seu avanço, porém, traz consigo preocupações sobre os efeitos de seu cultivo sobre a fauna nativa, pois, embora possua perfil florestal, é ainda uma monocultura. A área do presente estudo localizase no município de Angatuba, Estado de São Paulo, na Bacia do Alto Paranapanema. O presente estudo abrangeu plantios com idades de um ano e quatro meses a quatro anos e dá continuidade ao estudo desenvolvido no início do plantio (0 a 2 anos e 11 meses) na mesma área por Martin et al. (2012), seguindo a mesma metodologia. A coleta dos pequenos mamíferos foi realizada por meio de armadilhas de interceptação e queda (pitfall) distribuídas em grade em trinta unidades amostrais numa paisagem silvicultural, formada remanescentes florestais nativos, capoeira e eucaliptal a partir da metodologia amostral utilizada pelo Programa de Pesquisa em biodiversidade (PPBio), do Ministério da Ciência e Tecnologia (MCT). Foram capturadas 11 espécies pertencentes às ordens Rodentia e Didelphimorphia comumente encontradas em ambientes alterados e paisagens agrícolas. Não houve diferença significativa entre os ambientes testados em termos de riqueza de espécies e abundância de indivíduos. Dessa forma, os eucaliptais atuaram como habitat para as espécies e não apenas como matriz permeável. Por esta razão, seu manejo, incluindo práticas culturais (e.g., adubação e controle de plantas \"daninhas\") deverá levar em conta seu uso pela fauna silvestre e não apenas sua rentabilidade. Pesquisas futuras nessa área devem ser por isso, priorizadas a fim de garantir a missão multifuncional da paisagem silvicultural.Eucalyptus plantation was introduced in Brazil on early twentieth century and it aimed to supply with feedstock the furnaces and railroads under construction at the time. The production had various purposes and is still rising; therefore, currently eucalyptus plantation occupies more than four million hectares in Brazil. Its progress, however, highlights some concerns about the effects of cultivation on the native fauna because eucalyptus plantation is a monoculture although it has forestry profile. The present study area is located in the municipality of Angatuba, State of Sao Paulo, in the Upper Paranapanema Basin. This study sampled plantations aged between one year and four months and four years and continued the study developed on early planting (0-2 years and eleven months) by Martin et al. (2012) in the same area therefore the present study followed the same methodology. The capture of small mammals was conducted using pitfall traps distributed in a grid with thirty sample units in a silvicultural landscape formed by native forest remnants, \"capoeira\" and eucalyptus plantation. This method is based on the sampling methodology developed by Biodiversity Research Program (PPBio) and Ministry of Science and Technology (MCT). We captured 11 species from the orders Rodentia and Didelphimorphia commonly found in disturbed habitats and agricultural landscapes. There was no significant difference between the tested environments in terms of species richness and abundance of individuals. Thus, the eucalyptus plantation acted as habitat to those species and not just as permeable matrix. For this reason, eucalyptus plantation management, including cultural practices (e.g., fertilization and weed control) should take into account its use by wildlife and not just its profitability. Future research in this area should therefore prioritize to ensure the multifunctional mission of silviculture landscapes
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
