94 research outputs found

    Age constraints and fine tuning in variable-mass particle models

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    VAMP (variable-mass particles) scenarios, in which the mass of the cold dark matter particles is a function of the scalar field responsible for the present acceleration of the Universe, have been proposed as a solution to the cosmic coincidence problem, since in the attractor regime both dark energy and dark matter scale in the same way. We find that only a narrow region in parameter space leads to models with viable values for the Hubble constant and dark energy density today. In the allowed region, the dark energy density starts to dominate around the present epoch and consequently such models cannot solve the coincidence problem. We show that the age of the Universe in this scenario is considerably higher than the age for noncoupled dark energy models, and conclude that more precise independent measurements of the age of the Universe would be useful in distinguishing between coupled and noncoupled dark energy models.Comment: 7 pages, 8 figures, matches the Phys. Rev. D published versio

    Circulating microparticles and central blood pressure according to antihypertensive strategy

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    OBJECTIVES: This prospective, randomized, open-label study aimed to compare the effects of antihypertensive treatment based on amlodipine or hydrochlorothiazide on the circulating microparticles and central blood pressure values of hypertensive patients. METHODS: The effects of treatments on circulating microparticles were assessed during monotherapy and after the consecutive addition of valsartan and rosuvastatin followed by the withdrawal of rosuvastatin. Each treatment period lasted for 30 days. Central blood pressure and pulse wave velocity were measured at the end of each period. Endothelial, monocyte, and platelet circulating microparticles were determined by flow cytometry. Central blood pressure values and pulse wave velocity were recorded at the end of each treatment period. RESULTS: No differences in brachial blood pressure were observed between the treatment groups throughout the study. Although similar central blood pressure values were observed during monotherapy, lower systolic and diastolic central blood pressure values and early and late blood pressure peaks were observed in the amlodipine arm after the addition of valsartan alone or combined with rosuvastatin. Hydrochlorothiazide-based therapy was associated with a lower number of endothelial microparticles throughout the study, whereas a higher number of platelet microparticles was observed after rosuvastatin withdrawal in the amlodipine arm. CONCLUSIONS: Despite similar brachial blood pressure values between groups throughout the study, exposure to amlodipine was associated with lower central blood pressure values after combination with valsartan, indicating a beneficial interaction. Differences between circulating microparticles were modest and were mainly influenced by rosuvastatin withdrawal in the amlodipine arm

    Avaliação de genótipos de Leucaena spp. nas condições edafoclimáticas de São Carlos,SP: II. determinações bromatológicas no período de estabelecimento

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    In a trial conducted on a distrofic Red-Yellow Latossol, at EMBRAPA-CPPSE, São Carlos, located at 22°01'S and 47'53'W, altitude of 856 m and with a mean annual rainfall of 1502 mm, the bromatological composition of leaves, stems smaller than 6 mm diameter and pods of leucena genotypes was determined. The genotypes evaluated were: L.leucocephala cv. Texas 1074 (T1), L.leucocephala 29 A9 (T2), L.leucocephala 11 x L.dlversifolia 25 (T3), L.leucocephala 11 x L.diverstfolia 26 (T4), L.leucocephala 24-19/2-39 x L.diversifolia 26 (T5) and L.leucocephala cv. Cunningham (control). It was found that: - The evaluated genotypes did not show differences among themselves for bromatological determinations on leaves and fine stems; - T3 genotype had the greatest content of crude protein (28.06%), phosphorus (0.29%), the greatest PB/FDN relation, and the smaller FDN content of pods; - The genotypes presented the following average percentual contents of the bromatological composition of leaves, pods and stems smaller than 6 mm diameter, respectively: Crude Protein (18.57; 21.68; 6.41); Neutral detergent fiber (29.09; 41.58; 71.01); Phosphorus (0.12; 0.22; 0.06); Calcium (1.39; 0.36; 0.49); Magnesium (0.51; 0.28; 0.24); Tannin (1.32; 1.15; 0.28) and "in vitro" digestibility (58J9; 61.22; 33.61); - Protein and phosphorus contents presented the following decreasing order in plant parts: pods >; leaves >; stems smaller than 6 mm diameter; calcium contents: leaves >; stems smaller than 6 mm diameter >; pods; and the magnesium: leaves >; pods >; stems smaller than 6 mm diameter.Em experimento conduzido em Latossolo Vermelho-Amarelo distrófico, em área da EMBRAPA - CPPSE em São Carlos, situada a 22°01'S e 47°53'W, com altitude de 856 m e média de precipitação anual de 1502 mm, procedeu-se a determinação da composição bromatológicade folhas, hastes com diâmetro menor que 6 mm e vagens, de genótipos de leucena. Os genótipos avaliados, foram: L.leucocephala cv. Texas 1074 (TI), L.leucocephala 29 A9 (T2), L.leucocephala 11 x L.dlversifolia 25 (T3), L.leucocephala 11 x L.diversifolia 26 (T4), L.leucocephala 24-19/2-39 x L.diverstfolia 26 (T5) e L.leucocephala c v. Cunningham (testemunha). Verificou-se que: os genótipos avahados não apresentaram diferenças nas determinações bromatológicas, realizadas nas folhas e talos finos; o genótipo T3 registrou o maior teor de proteína bruta (28,06%), de fósforo (0,29%) e a maior relação PB/FDN e o menor teor de FDN para vagens; os genótipos apresentaram os seguintes teores médios, em porcentagem, para a composição bromatológicadas folhas, vagens e talos finos, respectivamente: Proteína bruta (18,57; 21,68; 6,41); Fibra detergente neutro (29,09; 41,58; 71,01); Fósforo (0,12; 0,22; 0,06); Cálcio (1,39; 0,36; 0,49); Magnesio (0,51; 0,28; 0,24); Tanino (1,32; 1,15; 0,28) e Digestibilidade "in vitro" (58,39; 61,22; 33,61); os teores de proteína e fósforo apresentaram a seguinte ordem decrescente nas partes das plantas: vagens >; folhas >; talos finos; os teores de cálcio: folhas >; talos finos >; vagens e de magnésio: folhas >; vagens >; talos finos

    Avaliação de genótipos de Leucaena spp. nas condições edafoclimáticas de São Carlos, SP: I. caracterização fenotípica e avaliação agronômica

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    To test promising genotypes of Leucaena spp., selected in a breeding program, an experiment was conducted in a distrofic Red-Yellow Latossol, at the experimental station of EMBRAPA/CPPSE, São Carlos,SP, located at 22°01' and 47°53'W, altitude of 856 m and with a mean annual precipitation of 1502 mm. The following genotypes were tested: L.leucocephala cv. Texas 1074 (T1), L.leucocephala 29 A9 (T2), L.leucocephala 11 x L.diversifolia 25 (T3), L.leucocephala 11 x L.diversifolia 26 (T4), L.leucocephala 24-19/2-39 x L.diversifolia 26 (T5) and L.leucocephala cv. Cunningham (control). Evaluations were performed during the establishment period (fifteen months) and it was concluded that: a) the plants of L.leucocephala 24-19/2-39 x L.diversifolia 26, with early flowering, were the most branched and presented the greatest seed yield; b) the plants of L.leucocephala 11 x L.diversifolia 26, showed the greatest edible dry matter yield; c) the genotypes presented similar or worse growth, than the control, after each harvest.Para avaliar genótipos promissores de Leucaena spp., foi instalado experimento em Latossolo Vermelho-Amarelo distrófico, na área da EMBRAPA-CPPSE em São Carlos, situada a 22°01'S e 47°53'W, com altitude de 856 m e média de precipitação anual de 1502 mm. Foram testados os seguintes genótipos: Leucaena leucocephala cv. Texas 1074 (T1), L.leucocephala 29 A9 (T2), L.leucocephala 11 x L.diversifolia 25 (T3), L.leucocephala 11 x L.leucocephala 26 (T4), L.leucocephala 24-19/2-39 X L.diversifolia 26 (T5) e L.leucocephala cv. Cunningham (testemunha). Através das avaliações efetuadas durante o período de estabelecimento (15 meses), verificou-se que: a) as plantas de L.leucocephala 24-19/2-39 x L.diversifolia 26 se mostraram mais ramificadas e com maior produção de sementes; b) as plantas de L.leucocephala 11 x L.diversifolia 26 apresentaram a maior produção de matéria seca consumível; c) os materiais apresentaram brotação após o corte, semelhante ou inferior à testemunha

    On exact solutions for quintessential (inflationary) cosmological models with exponential potentials

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    We first study dark energy models with a minimally-coupled scalar field and exponential potentials, admitting exact solutions for the cosmological equations: actually, it turns out that for this class of potentials the Einstein field equations exhibit alternative Lagrangians, and are completely integrable and separable (i.e. it is possible to integrate the system analytically, at least by quadratures). We analyze such solutions, especially discussing when they are compatible with a late time quintessential expansion of the universe. As a further issue, we discuss how such quintessential scalar fields can be connected to the inflationary phase, building up, for this class of potentials, a quintessential inflationary scenario: actually, it turns out that the transition from inflation toward late-time exponential quintessential tail admits a kination period, which is an indispensable ingredient of this kind of theoretical models. All such considerations have also been done by including radiation into the model.Comment: Revtex4, 10 figure

    The Brazilian Developments On The Regional Atmospheric Modeling System (brams 5.2): An Integrated Environmental Model Tuned For Tropical Areas

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We present a new version of the Brazilian developments on the Regional Atmospheric Modeling System (BRAMS), in which different previous versions for weather, chemistry, and carbon cycle were unified in a single integrated modeling system software. This new version also has a new set of state-of-the-art physical parameterizations and greater computational parallel and memory usage efficiency. The description of the main model features includes several examples illustrating the quality of the transport scheme for scalars, radiative fluxes on surface, and model simulation of rainfall systems over South America at different spatial resolutions using a scale aware convective parameterization. Additionally, the simulation of the diurnal cycle of the convection and carbon dioxide concentration over the Amazon Basin, as well as carbon dioxide fluxes from biogenic processes over a large portion of South America, are shown. Atmospheric chemistry examples show the model performance in simulating near-surface carbon monoxide and ozone in the Amazon Basin and the megacity of Rio de Janeiro. For tracer transport and dispersion, the model capabilities to simulate the volcanic ash 3-D redistribution associated with the eruption of a Chilean volcano are demonstrated. The gain of computational efficiency is described in some detail. BRAMS has been applied for research and operational forecasting mainly in South America. Model results from the operational weather forecast of BRAMS on 5km grid spacing in the Center for Weather Forecasting and Climate Studies, INPE/Brazil, since 2013 are used to quantify the model skill of near-surface variables and rainfall. The scores show the reliability of BRAMS for the tropical and subtropical areas of South America. Requirements for keeping this modeling system competitive regarding both its functionalities and skills are discussed. Finally, we highlight the relevant contribution of this work to building a South American community of model developers. © Author(s) 2017.1011892222014/01563-1, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo2014/01564-8, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo2015/10206-0, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo306340/2011-9, Conselho Nacional de Desenvolvimento Científico e TecnológicoFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Genetic diversity in natural populations of Jacaranda decurrens Cham. determined using RAPD and AFLP markers

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    Jacaranda decurrens (Bignoniaceae) is an endemic species of the Cerrado with validated antitumoral activity. The genetic diversity of six populations of J. decurrens located in the State of São Paulo was determined in this study by using molecular markers for randomly amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP). Following optimization of the amplification reaction, 10 selected primers generated 78 reproducible RAPD fragments that were mostly (69.2%) polymorphic. Two hundred and five reproducible AFLP fragments were generated by using four selected primer combinations; 46.3% of these fragments were polymorphic, indicating a considerable level of genetic diversity. Analysis of molecular variance (AMOVA) using these two groups of markers indicated that variability was strongly structured amongst populations. The unweighted pair group method with arithmatic mean (UPGMA) and Pearson's correlation coefficient (RAPD -0.16, p = 0.2082; AFLP 0.37, p = 0.1006) between genetic matrices and geographic distances suggested that the population structure followed an island model in which a single population of infinite size gave rise to the current populations of J. decurrens, independently of their spatial position. The results of this study indicate that RAPD and AFLP markers were similarly efficient in measuring the genetic variability amongst natural populations of J. decurrens. These data may be useful for developing strategies for the preservation of this medicinal species in the Cerrado
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