489 research outputs found

    The effects of tax incentives for small firms on employment levels

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    This paper will examine the effects of tax incentives for small businesseson employment level evaluating a program with this purpose implemented in Brazil in the 1990s. We first develop a theoretical framework which guides both the de nition of the parameters of interest and their identi cation. Selection problems both into the treatment group and into the data sampleare tackled by combining fi xed effects methods and regression discontinuity design on alternative sub-samples of a longitudinal database of manufacturing fi rms. The results show that on the one hand the size composition of thetreated fi rms may be changed due to the survival of some smaller fi rms that would have exited had it not been eligible to the program. On the other hand, the treated fi rms who do not depend on the program to survive do employ more workers.

    Exchange rate and fundamentals: the case of Brazil

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    O desempenho de previsão para fora da amostra é testado para um amplo conjunto de modelos empíricos de taxa de câmbio em uma economia emergente com taxa de câmbio flutuante e regime de metas de inflação. Comparado à literatura recente de modelos de previsão da taxa de câmbio, nós incluímos um conjunto mais extenso de modelos. São testados modelos tradicionais da década de 1980, modelos de equilíbrio comportamental da taxa de câmbio dos anos de 1990 e um modelo baseado na regra de Taylor. Neste último, o modelo incorpora um função de reação do Banco Central, na qual a taxa de juros é definida de acordo com uma regra de Taylor. Nossos resultados demonstram que modelos de regra de Taylor e de equilíbrio comportamental da taxa de câmbio, este último combinando diferenciais de produtividade com ajustes de carteira, têm desempenho fora da amostra superior a um passeio aleatório. Evidências de poder de previsão também são obtidas para modelos parcimoniosos baseados em argumentos de paridade descoberta da taxa de juros.Forecasting performance is tested for a broad set of empirical exchange rate models for an emerging economy with independently floating regime and inflation target monetary arrangement. Compared to the recent literature on out-of-sample exchange rate predictability, we include a more extensive set of models. We test vintage monetary models of the 1980's, exchange rate equilibrium models of the 1990's and a Taylor Rule based model. This last model assumes an endogenous monetary policy, where the Central Bank follows a Taylor rule reaction function to set interest rates. Our results show that Taylor Rule models and Behavioral Equilibrium Exchange Rate models, the last one combining productivity differentials with portfolio balance effect, have superior predictive accuracy when compared to the random walk benchmark. Some out-of-sample predictability is also obtained with parsimonious models based on uncovered interest parity arguments

    Determinantes da expansão do emprego formal: o que explica o aumento do tamanho médio dos estabelecimentos?

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    Esse trabalho tem o intuito de contribuir para a investigação dos determinantes da aceleração no crescimento do emprego formal na última década. As evidências apresentadas apontam que essa aceleração se deve a uma reversão na tendência do númeromédio de empregados por estabelecimento, em contraponto a uma tendência de crescimento constante no número de estabelecimentos. Investigaçõesmais detalhadas mostram evidências de que esse resultado não é derivado de mudanças na composição setorial que favoreça setores com maiores escalas de operação, nem um aprofundamento do processo de seleção que penaliza os pequenos estabelecimentos. As evidências apontam que a seleção teria contribuído para uma diminuição do tamanho médio, mas esse efeito foi contrabalançado por um nível de emprego maior nas firmas mais novas.The main goal of this paper is to analyze the increase of Brazilian formal employment growth rate in the last decade. The evidence suggests that this acceleration is due to a reversal in the trend of the average number of employees per establishment. More detailed investigations show evidence that this result is not derived from changes in industry composition that favors sectors with larger scales of operation, or a deepening of the process of selection, which penalizes the smaller establishments. As a matter of fact the selection component would have contributed to a decrease in the average firm size, but this effect was counterbalanced by a higher initial employment level in the most recent firms cohort

    Magnon delocalization in ferromagnetic chains with long-range correlated disorder

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    We study one-magnon excitations in a random ferromagnetic Heisenberg chain with long-range correlations in the coupling constant distribution. By employing an exact diagonalization procedure, we compute the localization length of all one-magnon states within the band of allowed energies EE. The random distribution of coupling constants was assumed to have a power spectrum decaying as S(k)1/kαS(k)\propto 1/k^{\alpha}. We found that for α<1\alpha < 1, one-magnon excitations remain exponentially localized with the localization length ξ\xi diverging as 1/E. For α=1\alpha = 1 a faster divergence of ξ\xi is obtained. For any α>1\alpha > 1, a phase of delocalized magnons emerges at the bottom of the band. We characterize the scaling behavior of the localization length on all regimes and relate it with the scaling properties of the long-range correlated exchange coupling distribution.Comment: 7 Pages, 5 figures, to appear in Phys. Rev.

    Spectrochemical analysis in blood plasma combined with subsequent chemometrics for fibromyalgia detection

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    Fibromyalgia is a rheumatologic condition characterized by multiple and chronic body pain, and other typical symptoms such as intense fatigue, anxiety and depression. It is a very complex disease where treatment is often made by non-medicated alternatives in order to alleviate symptoms and improve the patient’s quality of life. Herein, we propose a method to detect patients with fibromyalgia (n = 252, 126 controls and 126 patients with fibromyalgia) through the analysis of their blood plasma using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy in conjunction with chemometric techniques, hence, providing a low-cost, fast and accurate diagnostic approach. Different chemometric algorithms were tested to classify the spectral data; genetic algorithm with linear discriminant analysis (GA-LDA) achieved the best diagnostic results with a sensitivity of 89.5% in an external test set. The GA-LDA model identified 24 spectral wavenumbers responsible for class separation; amongst these, the Amide II (1,545 cm−1) and proteins (1,425 cm−1) were identified to be discriminant features. These results reinforce the potential of ATR-FTIR spectroscopy with multivariate analysis as a new tool to screen and detect patients with fibromyalgia in a fast, low-cost, non-destructive and minimally invasive fashion

    In vitro effect of seven essential oils on the reproduction of the cattle tick Rhipicephalus microplus

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    AbstractThe acaricidal effect of seven essential oils was examined in vitro against the cattle tick (Rhipicephalus microplus). Engorged female ticks were manually collected in farms of Southern Brazil and placed into petri dishes (n=10) in order to test the following oils: juniper (Juniperus communis), palmarosa (Cymbopogon martinii), cedar (Cedrus atlantica), lemon grass (Cymbopogon citratus), ginger (Zingiber officinale), geranium (Pelargonium graveolens) and bergamot (Citrus aurantium var bergamia) at concentrations of 1%, 5%, and 10% each. A control group was used to validate the tests containing Triton X-100 only. Treatment effectiveness was measured considering inhibition of tick oviposition (partial or total), egg’s weight, and hatchability. C. martinii, C. citratus and C. atlantica essential oils showed efficacy higher than 99% at all concentrations tested. In addition, J. communis, Z. officinale, P. graveolens, and C. aurantium var bergamia oils showed efficiency ranging from 73% to 95%, depending on the concentration tested, where higher concentrations showed greater efficacy. It was concluded that essential oils can affect tick reproduction in vitro by inhibiting oviposition and hatchability

    Shelf morphology as an indicator of sedimentary regimes: a synthesis from a mixed siliciclastic-carbonate shelf on the eastern Brazilian margin

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    Modern shelf morphology is the result of the interplay between short and long term sedimentary processes. The relation between rates of sediment supply/carbonate growth and accommodation space creation will not only control coastal transgression and regression, but will also define the shelf sedimentary regimes acting to shape the seabed. Herein, shelf morphology and sedimentology are investigated in order to discuss how these characteristics can be representative of distinct sedimentary regimes. The study area is the eastern Brazilian shelf where coastal transgression and regression coexist with the most important coral reef system of the South Atlantic. A compilation of existing published and unpublished data was carried out in order to produce morphological and faciological maps and compare the mapped features with high-resolution seismic and sonographic data. The results show three major regions or morphological compartments: Abrolhos Shelf, Doce River Shelf and the Paleovalleys Shelf. In terms of shelf sedimentary domain, rhodolith beds predominate over the outer shelf along the entire area, coralline reefs are present along the northern Abrolhos inner shelf and a significant terrigenous mud deposit is observed associated to the Doce River adjacent inner shelf beds. The rest of the shelf is composed by bioclastic or terrigenous mud sand and gravel. Terrigenous sedimentation is always restricted to the shoreface or inner shelf shallower areas and carbonate sands and gravels are predominant elsewhere. The Abrolhos shelf shows two distinct sectors; the northern area is a typical mixed sediment environment that has a supply regime along the coast/shoreface, mainly due to longshore transport and a carbonate regime along the inner and outer shelf. The southern shelf morphology and sedimentation are controlled by the antecedent topography and is typically a accommodation regime shelf with associated rhodolith beds. The Doce river shelf is a supply regime environment with the formation of a 5 to 8m thick regressive deposit with downlapping clinoforms. Southward from the Doce river shelf, a significant shift in sedimentary regime is observed as the morphology becomes very irregular with associated hardbottoms and unfilled paleovalleys. This sector of the shelf (Paleovalley shelf) is characterized by an accommodation regime. The interpretation shows that the entire study area can be defined as a mixed sedimentation shelf, showing supply and accommodation regimes. Shelf morphology worked as an indicator of these changes. Carbonate/terrigenous deposition during a highstand/regressive phase coeval along the eastern Brazilian shelf, either laterally and across shelf. This lateral/along coast variation in sediment supply and carbonate production leads to distinct lateral facies and geometry. These spatial changes in morphology and facies, with coexistence of carbonate and siliciclastic sedimentation, are very important for the correlation and interpretation of the geological record, especially stratigraphic surfaces and sequence units

    Reef fish and benthic assemblages of the Trindade and Martin Vaz Island group, southwestern Atlantic

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    O conjunto insular de Trindade e Martin Vaz (CITMV) está localizado a aproximadamente 1.120 km da costa brasileira. Apesar de sua importância, salientada pela presença de diversas espécies endêmicas de peixes, não existem informações detalhadas sobre as assembléias de peixes e bentos do CITMV. É apresentada aqui a primeira caracterização quantitativa das assembléias de peixes e bentos do CITMV em um gradiente de profundidade entre 5 e 45 m. Informações qualitativas adicionais sobre assembléias recifais entre 45 e 100 m foram obtidas utilizando-se técnicas avançadas de mergulho (TRIMIX) e um veículo de operação remota (VOR). Assim como outras ilhas oceânicas brasileiras, a CITMV possui assembléias depauperadas de peixes e bentos, possivelmente devido ao seu isolamento e pequeno tamanho em comparação ao continente. A profundidade foi o fator que mais afetou a estrutura das assembléias de peixes, com a densidade da maioria das espécies declinando com o aumento da profundidade. Os recifes profundos (>; 45 m) foram caracterizados pela presença de bancos extensivos de rodolitos e recifes rochosos esparsamente cobertos por algas coralináceas incrustantes, corais negros (Cirripathes sp.) e alguns corais massivos e em de forma de placa. Peixes parcialmente ou obrigatoriamente planctívoros (e.g. Cephalopholis furcifer and Clepticus brasiliensis) também dominaram em recifes profundos. Características similares foram registradas para recifes mesofóticos ao longo do Atlântico Ocidental. Evidências de sobrepesca (obtidas aqui e em outros estudos recentes), a presença de quatro espécies de peixes endêmicas e com distribuição restrita, e o aumento no número de espécies novas ainda não descritas, indicam que a adoção de medidas de conservação baseadas no princípio da precaução é urgentemente necessária para garantir a manutenção dos ecossistemas frágeis e únicos do CITMV.The Trindade and Martin Vaz island group (TMVIG) is located at about 1,120 km off the Brazilian coast. Despite its importance, highlighted by the presence of several endemic fish species, the TMVIG lacks detailed information on the structure of fish and benthic assemblages. Presented here is the first quantitative assessment of reef fish and benthic assemblages of the TMVIG in a depth gradient ranging from 5 to 45 m. Additional qualitative information on reef assemblages between 45 and 100 m was obtained using advanced gas diving techniques (TRIMIX) and a remotely operated vehicle (ROV). Similarly to other Brazilian oceanic islands, the TMVIG possesses depauperated fish and benthic assemblages, possibly due to its isolation and small size in comparison to the mainland. Depth was the most important factor affecting the structure of fish assemblages, with the density of most fish species declining with depth. Deep reefs (>; 45 m) were characterized by the presence of extensive rhodolith beds and rocky reefs sparsely covered with crustose coralline algae, black coral (Cirripathes sp.) and a few massive or plate-like reef corals. Part-time or obligatory planktivorous fishes (e.g. Cephalopholis furcifer and Clepticus brasiliensis) also dominated deep reefs. Similar characteristics were recorded in mesophotic reef ecosystems across the Western Atlantic. Evidence of overfishing (obtained here and in other recent studies), the presence of four endemic and restricted range fish species, as well as the increase in number of new (and still undescribed) endemic taxa, indicates that the adoption of precautionary conservation measures are urgently needed in order to maintain the fragile and unique ecosystems of the TMVIG
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