Análise da utilização de um modelo de quatro fatores como ferramenta auxiliar para gestão de carteiras baseadas no IBrX

Using the price series of the assets that compose the IBrX in the period from May 2002 to December 2007, this article examines the influence of the variables beta, market value, price-earnings ratio and book-to-market ratio on the behavior of the Brazilian stock market, comparing the results with those of other studies carried out in Brazil. On investigating the influence of beta, we sought to verify if the premises of the CAPM are valid in the model proposed. We used the SUR and TSCS techniques to estimate the influence of the variables. The results indicate the significance of price-earnings and market value, but the book-to-market ratio presented the greatest stability and was significant in all the proposed models. In relation to the CAPM, the study shows that all the variables analyzed had some degree of influence on the cross-sectional variations of the average stock returns, indicating that other factors besides beta can be associated with the behavior of the assets.Esta pesquisa utilizou como banco de dados os ativos que compuseram o índice IBrX no período de maio de 2002 a dezembro de 2007, examinando a influência das variáveis beta, valor de mercado, índice preço/lucro e índice valor contábil/valor de mercado no comportamento no mercado brasileiro, confrontando o resultado com outras pesquisas realizadas no Brasil. Ao investigar a influência do beta este trabalhou buscou verificar se as premissas adotadas pelo CAPM são válidas no modelo proposto por este estudo. As técnicas de estimação utilizadas nesta pesquisa para estimar o grau de influência das variáveis foram o SUR e o TSCS. Os resultados apontaram significância para as variáveis índice Preço/Lucro e valor de mercado. Porém, a variável valor contábil/valor de mercado foi a que apresentou maior estabilidade sendo significante em todos os modelos propostos. Em relação ao CAPM a pesquisa apontou que todas as variáveis analisadas apresentaram algum grau de influência nas variações cross-section das rentabilidades médias das ações, sinalizando que além do beta, outros fatores podem estar associados ao comportamento dos ativos

ATLANTIC EPIPHYTES: a data set of vascular and non-vascular epiphyte plants and lichens from the Atlantic Forest

Epiphytes are hyper-diverse and one of the frequently undervalued life forms in plant surveys and biodiversity inventories. Epiphytes of the Atlantic Forest, one of the most endangered ecosystems in the world, have high endemism and radiated recently in the Pliocene. We aimed to (1) compile an extensive Atlantic Forest data set on vascular, non-vascular plants (including hemiepiphytes), and lichen epiphyte species occurrence and abundance; (2) describe the epiphyte distribution in the Atlantic Forest, in order to indicate future sampling efforts. Our work presents the first epiphyte data set with information on abundance and occurrence of epiphyte phorophyte species. All data compiled here come from three main sources provided by the authors: published sources (comprising peer-reviewed articles, books, and theses), unpublished data, and herbarium data. We compiled a data set composed of 2,095 species, from 89,270 holo/hemiepiphyte records, in the Atlantic Forest of Brazil, Argentina, Paraguay, and Uruguay, recorded from 1824 to early 2018. Most of the records were from qualitative data (occurrence only, 88%), well distributed throughout the Atlantic Forest. For quantitative records, the most common sampling method was individual trees (71%), followed by plot sampling (19%), and transect sampling (10%). Angiosperms (81%) were the most frequently registered group, and Bromeliaceae and Orchidaceae were the families with the greatest number of records (27,272 and 21,945, respectively). Ferns and Lycophytes presented fewer records than Angiosperms, and Polypodiaceae were the most recorded family, and more concentrated in the Southern and Southeastern regions. Data on non-vascular plants and lichens were scarce, with a few disjunct records concentrated in the Northeastern region of the Atlantic Forest. For all non-vascular plant records, Lejeuneaceae, a family of liverworts, was the most recorded family. We hope that our effort to organize scattered epiphyte data help advance the knowledge of epiphyte ecology, as well as our understanding of macroecological and biogeographical patterns in the Atlantic Forest. No copyright restrictions are associated with the data set. Please cite this Ecology Data Paper if the data are used in publication and teaching events. © 2019 The Authors. Ecology © 2019 The Ecological Society of Americ

NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non-detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio-temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large-scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data

Núcleos de Ensino da Unesp: artigos 2008

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq