221 research outputs found

    Variation of growth performance of the striped venus clam Chamelea gallina (Mollusca: Bivalvia) (Linnaeus, 1758) in relation to environmental variables along the southern part of its geographic range

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    This study reports relative growth, shell length-age keys and growth performance indices (overall growth performance (OGP) and phi prime) for the striped venus Chamelea gallina from the Huelva coast in southwest (SW) Spain. The morphometric relationship shell height (SH)/shell length (SL) presented isometric growth whereas SL/shell width (SW) and SL/weight (W) displayed negative allometric growth. Shell length at age was estimated through length-frequency distribution (LF) and internal shell growth bands by acetate peel method (AP). C. gallina population consists mainly of three age classes with shell lengths around 13-15 mm for the first year, 25 mm for the second year and 30 mm for the third year. The OGP and phi prime values obtained in the present study are within the range of values for other C. gallina populations from the Gulf of CĂĄdiz. Nevertheless, marked differences in growth performance were observed between populations from the Black Sea (lower growth performance) and from other locations along the southern distribution area of this species, which may be related to the low levels of temperature (SST), salinity (SSS) and chlorophyll-a (chl-a) concentration that exhibit large intra-annual fluctuations.En prensa0,371

    Developing a Plastic Waste Management Program: From River Basins to Urban Beaches (Case Study)

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    Solid waste accumulation in coastal environments has been a growing concern. In the coastal megacity of Recife, Pernambuco state, Brazil, plastic waste issues currently exist both at the ocean scale and river basin scale. The city is known as the 'Brazilian Venice' thanks to the Capibaribe River, which crosses many neighborhoods, running in a west-east direction into the Atlantic Ocean. This paper provides the initial basis to develop a Plastic Waste Management Program proposal for implementation in the city of Recife, given the lack of resolutions that have looked at plastic waste management through integrated water environment scales (from river basin to ocean). The methodology used included articulation and documental collection from four main public agencies from the state/city and stakeholders. The results showed its relevance for better plastic waste management in Recife, considering an integrated water environment on a river basin-to-ocean scale by using the recognized major connected water environments (Capibaribe river and Boa Viagem beach). Similar integrated program proposals could be made for other coastal areas, enabling not only the identification of fragilities but also the exchange of information regarding the theme

    Resolvin rvd2 reduces hypothalamic inflammation and rescues mice from diet-induced obesity

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    Diet-induced hypothalamic inflammation is an important mechanism leading to dysfunction of neurons involved in controlling body mass. Studies have shown that polyunsaturated fats can reduce hypothalamic inflammation. Here, we evaluated the presence and function of RvD2, a resolvin produced from docosahexaenoic acid, in the hypothalamus of mice. Methods: Male Swiss mice were fed either chow or a high-fat diet. RvD2 receptor and synthetic enzymes were evaluated by real-time PCR and immunofluorescence. RvD2 was determined by mass spectrometry. Dietary and pharmacological approaches were used to modulate the RvD2 system in the hypothalamus, and metabolic phenotype consequences were determined. Results: All enzymes involved in the synthesis of RvD2 were detected in the hypothalamus and were modulated in response to the consumption of dietary saturated fats, leading to a reduction of hypothalamic RvD2. GPR18, the receptor for RvD2, which was detected in POMC and NPY neurons, was also modulated by dietary fats. The substitution of saturated by polyunsaturated fats in the diet resulted in increased hypothalamic RvD2, which was accompanied by reduced body mass and improved glucose tolerance. The intracerebroventricular treatment with docosahexaenoic acid resulted in increased expression of the RvD2 synthetic enzymes, increased expression of anti-inflammatory cytokines and improved metabolic phenotype. Finally, intracerebroventricular treatment with RvD2 resulted in reduced adiposity, improved glucose tolerance and increased hypothalamic expression of anti-inflammatory cytokines. Conclusions: Thus, RvD2 is produced in the hypothalamus, and its receptor and synthetic enzymes are modulated by dietary fats. The improved metabolic outcomes of RvD2 make this substance an attractive approach to treat obesity14511

    Evidence for the Gompertz Curve in the Income Distribution of Brazil 1978-2005

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    This work presents an empirical study of the evolution of the personal income distribution in Brazil. Yearly samples available from 1978 to 2005 were studied and evidence was found that the complementary cumulative distribution of personal income for 99% of the economically less favorable population is well represented by a Gompertz curve of the form G(x)=exp⁥[exp⁥(A−Bx)]G(x)=\exp [\exp (A-Bx)], where xx is the normalized individual income. The complementary cumulative distribution of the remaining 1% richest part of the population is well represented by a Pareto power law distribution P(x)=ÎČx−αP(x)= \beta x^{-\alpha}. This result means that similarly to other countries, Brazil's income distribution is characterized by a well defined two class system. The parameters AA, BB, α\alpha, ÎČ\beta were determined by a mixture of boundary conditions, normalization and fitting methods for every year in the time span of this study. Since the Gompertz curve is characteristic of growth models, its presence here suggests that these patterns in income distribution could be a consequence of the growth dynamics of the underlying economic system. In addition, we found out that the percentage share of both the Gompertzian and Paretian components relative to the total income shows an approximate cycling pattern with periods of about 4 years and whose maximum and minimum peaks in each component alternate at about every 2 years. This finding suggests that the growth dynamics of Brazil's economic system might possibly follow a Goodwin-type class model dynamics based on the application of the Lotka-Volterra equation to economic growth and cycle.Comment: 22 pages, 15 figures, 4 tables. LaTeX. Accepted for publication in "The European Physical Journal B

    Indicadores de qualidade do solo em sistemas de cultivo orgĂąnico e convencional no semi-ĂĄrido Cearense.

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    A qualidade do solo pode mudar com o passar do tempo, em decorrĂȘncia de eventos naturais ou açÔes antrĂłpicas. A adoção de prĂĄticas de cultivo orgĂąnico reduz o revolvimento do solo, favorecendo a recuperação de suas propriedades fĂ­sicas e quĂ­micas. Este trabalho teve como objetivo comparar propriedades fĂ­sicas,quĂ­micas e biolĂłgicas de solos cultivados com algodĂŁo em bases orgĂąnicas e no sistema convencional, assim como identificar as que possam ser utilizadas como indicadores de qualidade do solo. Selecionaram-se seis ĂĄreas submetidas ao cultivo orgĂąnico e trĂȘs ao cultivo convencional para coleta de amostras de solo deformadas e indeformadas, nas camadas de 0–10, 10–20 e 20–30 cm. TĂ©cnicas de estatĂ­stica univariada e multivariada foram utilizadas para anĂĄlise dos dados. Os resultados mostraram que os indicadores fĂ­sicos e quĂ­micos testados individualmente nĂŁo foram sensĂ­veis para diferenciar as ĂĄreas sob sistema de cultivo orgĂąnico daquelas sob cultivo convencional. No entanto, a aplicação de tĂ©cnicas de anĂĄlise multivariada – no caso, componentes principais e a discriminante de Anderson – permitiu a distinção entre algumas ĂĄreas cultivadas sob cultivo orgĂąnico comparativamente Ă s convencionais, atĂ© mesmo as que estavam em transição.Dos indicadores biolĂłgicos, a fauna edĂĄfica mostrou-se mais precisa na avaliação da qualidade do solo, distinguindo de forma satisfatĂłria as ĂĄreas sob sistema de cultivo orgĂąnico das que estavam sob sistema convencional

    Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

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    Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic

    Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

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    Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{6×10196\times 10^{19}eV}. The anisotropy was measured by the fraction of arrival directions that are less than 3.1∘3.1^\circ from the position of an active galactic nucleus within 75 Mpc (using the V\'eron-Cetty and V\'eron 12th12^{\rm th} catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is (38−6+7)(38^{+7}_{-6})%, compared with 2121% expected for isotropic cosmic rays. This is down from the early estimate of (69−13+11)(69^{+11}_{-13})%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201

    The Fluorescence Detector of the Pierre Auger Observatory

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    The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics Research Section

    Advanced functionality for radio analysis in the Offline software framework of the Pierre Auger Observatory

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    The advent of the Auger Engineering Radio Array (AERA) necessitates the development of a powerful framework for the analysis of radio measurements of cosmic ray air showers. As AERA performs "radio-hybrid" measurements of air shower radio emission in coincidence with the surface particle detectors and fluorescence telescopes of the Pierre Auger Observatory, the radio analysis functionality had to be incorporated in the existing hybrid analysis solutions for fluoresence and surface detector data. This goal has been achieved in a natural way by extending the existing Auger Offline software framework with radio functionality. In this article, we lay out the design, highlights and features of the radio extension implemented in the Auger Offline framework. Its functionality has achieved a high degree of sophistication and offers advanced features such as vectorial reconstruction of the electric field, advanced signal processing algorithms, a transparent and efficient handling of FFTs, a very detailed simulation of detector effects, and the read-in of multiple data formats including data from various radio simulation codes. The source code of this radio functionality can be made available to interested parties on request.Comment: accepted for publication in NIM A, 13 pages, minor corrections to author list and references in v
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