1,958 research outputs found

    Stellar rotational periods in the planet hosting open cluster Praesepe

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    By using the dense coverage of the extrasolar planet survey project HATNet, we Fourier analyze 381 high-probability members of the nearby open cluster Praesepe (Beehive/M44/NGC 2632). In addition to the detection of 10 variables (of \delta Scuti and other types), we identify 180 rotational variables (including the two known planet hosts). This sample increases the number of known rotational variables in this cluster for spectral classes earlier than M by more than a factor of three. These stars closely follow a color/magnitude -- period relation from early F to late K stars. We approximate this relation by polynomials for an easier reference to the rotational characteristics in different colors. The total (peak-to-peak) amplitudes of the large majority (94%) of these variables span the range of 0.005 to 0.04 mag. The periods cover a range from 2.5 to 15 days. These data strongly confirm that Praesepe and the Hyades have the same gyrochronological ages. Regarding the two planet hosts, Pr0211 (the one with the shorter orbital period) has a rotational period that is ~2 days shorter than the one expected from the main rotational pattern in this cluster. This, together with other examples discussed in the paper, may hint that star-planet interaction via tidal dissipation can be significant in some cases in the rotational evolution of stars hosting Hot Jupiters.Comment: 17 pages, 13 figures, 5 tables; accepted for publication in MNRA

    Sparse-matrix Representation of Spiking Neural P Systems for GPUs

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    Current parallel simulation algorithms for Spiking Neural P (SNP) systems are based on a matrix representation. This helps to harness the inherent parallelism in algebraic operations, such as vector-matrix multiplication. Although it has been convenient for the rst parallel simulators running on Graphics Processing Units (GPUs), such as CuSNP, there are some bottlenecks to cope with. For example, matrix representation of SNP systems with a low-connectivity-degree graph lead to sparse matrices, i.e. containing more zeros than actual values. Having to deal with sparse matrices downgrades the performance of the simulators because of wasting memory and time. However, sparse matrices is a known problem on parallel computing with GPUs, and several solutions and algorithms are available in the literature. In this paper, we brie y analyse some of these ideas and apply them to represent some variants of SNP systems. We also conclude which variant better suit a sparse-matrix representation

    SensoGraph: Using proximity graphs for sensory analysis

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    Sensory evaluation of foods is as important as chemical, physical or microbiological examinations, being specially relevant in food industries. Classical methods can be long and costly, making them less suitable for certain industries like the wine industry. Some alternatives have arisen recently, including Napping®, where the tasters represent the sensory distances between products by positioning them on a tablecloth; the more similar they perceive the products, the closer they position them on the tablecloth. This method uses multiple factor analysis (MFA) to process the data collected. The present paper introduces the software SensoGraph, which makes use of proximity graphs to analyze those data. The application is described and experimental results are presented in order to compare the performances of SensoGraph and Napping®, using eight wines from the Toro region and two groups of twelve tasters with different expertise.Ministerio de Ciencia e InnovaciónEuropean Science FoundationJunta de Castilla y Leó

    Updated standardized joint CPUE index for bluefin tuna (Thunnus thynnus) caught by Moroccan and Spanish traps for the period 1981- 2012.

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    Relative abundance indices of bluefin tuna (Thunnus thynnus) caught by the Moroccan and Spanish traps in the area close to the Strait of Gibraltar were estimated for the period 1981- 2013. Standardized CPUEs were estimated through a General Linear Modeling (GLM) approach under a negative binomial error distribution assumption.Versión del edito

    UPDATED STANDARDIZED JOINT CPUE INDEX FOR BLUEFIN TUNA (THUNNUS THYNNUS) CAUGHT BY MOROCCAN AND SPANISH TRAPS FOR THE PERIOD 1981- 2011

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    Relative abundance indices of bluefin tuna (Thunnus thynnus) caught by the Moroccan and Spanish traps in the area close to the Strait of Gibraltar were estimated for the period 1981- 2011. Standardized CPUEs were estimated through a General Linear Modeling (GLM) approach under a negative binomial error distribution assumption.Postprin

    Statistical Mechanics Analysis of LDPC Coding in MIMO Gaussian Channels

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    Using analytical methods of statistical mechanics, we analyse the typical behaviour of a multiple-input multiple-output (MIMO) Gaussian channel with binary inputs under LDPC network coding and joint decoding. The saddle point equations for the replica symmetric solution are found in particular realizations of this channel, including a small and large number of transmitters and receivers. In particular, we examine the cases of a single transmitter, a single receiver and the symmetric and asymmetric interference channels. Both dynamical and thermodynamical transitions from the ferromagnetic solution of perfect decoding to a non-ferromagnetic solution are identified for the cases considered, marking the practical and theoretical limits of the system under the current coding scheme. Numerical results are provided, showing the typical level of improvement/deterioration achieved with respect to the single transmitter/receiver result, for the various cases.Comment: 25 pages, 7 figure

    Sexualized drug use among men who have sex with men in Madrid and Barcelona: The gateway to new drug use?

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    Men who have sex with men; Sexualized drug useHomes que tenen sexe amb homes; Consum sexual de droguesHombres que tienen sexo con hombres; Consumo sexual de drogasThis original study compares the prevalences of drug use for any purpose and for sexualized drug use (SDU) among MSM. It also describes relevant characteristics of first SDU, analyzes to what extent SDU has been the first experience (the gateway) with different drugs by age and explores the correlates of SDU. Study participants included 2,919 HIV-negative MSM attending four HIV/STI diagnosis services in Madrid and Barcelona. They answered an online, self-administered questionnaire. Poisson regression models with robust variance were used. About 81.4% had ever used any drug, and 71.9% had done so in the last-12-months, while 56% had ever engaged in SDU, and 50% had done so in the last-12-months. Participants under 25 years old had the lowest prevalences of SDU, and the 25–39 age group the highest, except for Viagra, which was higher among those over age 40. The most frequently used drugs for first SDU were poppers (53.6%), cannabis (19.6%) and Viagra (12.2%). These drugs were also the most ever consumed for SDU. Among sexualized users, methamphetamine (78.3%) and Mephedrone (75.4%) were used always/most of the times for sex in the last-12-months. Around 72.2% of Mephedrone sexualized users and 69.6% of Methamphetamine vs 23.1% of ecstasy users' first consumption of these drugs involved use for sex. These drugs were provided to them free where they have sex for 66.8, 79.1, and 31.9%, respectively. On that occasion, 8.1% of Mephedrone, 6.8% of Methamphetamine and 18.4% of ecstasy users had sex only with steady partner; with 50.2, 56.2, and 26.2% respectively using a condom with any partner. SDU in the first use was associated with similar variables for recreational and chemsex drugs. The highest prevalence ratios were for having ever been penetrated by >20 men and having ever injected drugs. It can be concluded that the prevalence of SDU was more than half of the prevalence for any purpose. Thus SDU was the gateway to use for many drugs in an important proportion of users, who frequently consumed drugs that were free and had condomless anal sex with occasional and multiple partners. These circumstances were much more common for chemsex than for recreational drugs.This study was supported by the Delegación del Gobierno para el Plan Nacional sobre Drogas (2019I017)

    Sexualized drug use among men who have sex with men in Madrid and Barcelona: The gateway to new drug use?

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    This original study compares the prevalences of drug use for any purpose and for sexualized drug use (SDU) among MSM. It also describes relevant characteristics of first SDU, analyzes to what extent SDU has been the first experience (the gateway) with different drugs by age and explores the correlates of SDU. Study participants included 2,919 HIV-negative MSM attending four HIV/STI diagnosis services in Madrid and Barcelona. They answered an online, self-administered questionnaire. Poisson regression models with robust variance were used. About 81.4% had ever used any drug, and 71.9% had done so in the last-12-months, while 56% had ever engaged in SDU, and 50% had done so in the last-12-months. Participants under 25 years old had the lowest prevalences of SDU, and the 25-39 age group the highest, except for Viagra, which was higher among those over age 40. The most frequently used drugs for first SDU were poppers (53.6%), cannabis (19.6%) and Viagra (12.2%). These drugs were also the most ever consumed for SDU. Among sexualized users, methamphetamine (78.3%) and Mephedrone (75.4%) were used always/most of the times for sex in the last-12-months. Around 72.2% of Mephedrone sexualized users and 69.6% of Methamphetamine vs 23.1% of ecstasy users' first consumption of these drugs involved use for sex. These drugs were provided to them free where they have sex for 66.8, 79.1, and 31.9%, respectively. On that occasion, 8.1% of Mephedrone, 6.8% of Methamphetamine and 18.4% of ecstasy users had sex only with steady partner; with 50.2, 56.2, and 26.2% respectively using a condom with any partner. SDU in the first use was associated with similar variables for recreational and chemsex drugs. The highest prevalence ratios were for having ever been penetrated by >20 men and having ever injected drugs. It can be concluded that the prevalence of SDU was more than half of the prevalence for any purpose. Thus SDU was the gateway to use for many drugs in an important proportion of users, who frequently consumed drugs that were free and had condomless anal sex with occasional and multiple partners. These circumstances were much more common for chemsex than for recreational drugs.This study was supported by the Delegación del Gobierno para el Plan Nacional sobre Drogas (2019I017)S

    Local indicators for global species: Pelagic sharks in the tropical northeast Atlantic, Cabo Verde islands region

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    Pelagic sharks are an important bycatch in pelagic fisheries, especially for drifting longlines targeting swordfish. In the Cabo Verde Archipelago (tropical NE Atlantic), pelagic shark catches can reach a significant proportion of the total catches. Due to the increased concern on the status of pelagic shark species, this study was developed to enhance the current knowledge of those sharks in the Cabo Verde region in comparison to the adjacent areas, especially associated with European Union (EU) pelagic longline fishing activity. Stock status indicators for the two main species, blue shark (Prionace glauca) and shortfin mako (Isurus oxyrinchus), were developed, based on fisheries data from logbooks and onboard scientific observers, including analysis of size frequency distributions and standardized catch-per-unit-of-effort (CPUE) indexes over time. The standardized CPUEs have been stable or increasing for both species in the past 10 years, indicating no signs of local depletion. In terms of sizes, the blue shark catch is composed mainly of adults, which can be a sign of a stable population. On the contrary, the catch of shortfin mako is composed mainly of juveniles, which in conjunction of a decrease of mean size might be a cause of concern, highlighting possible overfishing on the species in the region. Thirty satellite tags, 25 archival miniPATs and 5 SPOT GPS, were deployed in the Cabo Verde Exclusive Economic Zone (EEZ), showing that those species are highly mobile. The biomass and size distributions were modeled with spatial and seasonal models (GAMs) identifying locations where juveniles are predominantly concentrated and that should be prioritized for conservation. This work presents new information on the status of pelagic sharks in the Cabo Verde region in the context of those highly migratory species, and can now be used to promote more sustainable fisheries in the region.FCT IF/00253/2014, SFRH/BD/136074/2018, SFRH/BD/139187/2018, EU/MARE/2012/21: “Scientific advice for fisheries beyond EU waters”, specifically within Specific Contract N° 7: “The provision of advice on the conservation of pelagic sharks associated to fishing activity under EU Sustainable Fisheries Partnership Agreements in the Atlantic Ocean”.info:eu-repo/semantics/publishedVersio

    Hydrogen Epoch of Reionization Array (HERA)

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    The Hydrogen Epoch of Reionization Array (HERA) is a staged experiment to measure 21 cm emission from the primordial intergalactic medium (IGM) throughout cosmic reionization (z=612z=6-12), and to explore earlier epochs of our Cosmic Dawn (z30z\sim30). During these epochs, early stars and black holes heated and ionized the IGM, introducing fluctuations in 21 cm emission. HERA is designed to characterize the evolution of the 21 cm power spectrum to constrain the timing and morphology of reionization, the properties of the first galaxies, the evolution of large-scale structure, and the early sources of heating. The full HERA instrument will be a 350-element interferometer in South Africa consisting of 14-m parabolic dishes observing from 50 to 250 MHz. Currently, 19 dishes have been deployed on site and the next 18 are under construction. HERA has been designated as an SKA Precursor instrument. In this paper, we summarize HERA's scientific context and provide forecasts for its key science results. After reviewing the current state of the art in foreground mitigation, we use the delay-spectrum technique to motivate high-level performance requirements for the HERA instrument. Next, we present the HERA instrument design, along with the subsystem specifications that ensure that HERA meets its performance requirements. Finally, we summarize the schedule and status of the project. We conclude by suggesting that, given the realities of foreground contamination, current-generation 21 cm instruments are approaching their sensitivity limits. HERA is designed to bring both the sensitivity and the precision to deliver its primary science on the basis of proven foreground filtering techniques, while developing new subtraction techniques to unlock new capabilities. The result will be a major step toward realizing the widely recognized scientific potential of 21 cm cosmology.Comment: 26 pages, 24 figures, 2 table
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