502 research outputs found

    Análises morfométricas entre apis mellifera da mesorregiao do sertao paraibano

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    Objetivou-se, com esse trabalho, caracterizar as populações de Apis mellifera da mesorregião do Sertão paraibano, comparando os indivíduos morfometricamente. As medidas tomadas foram: comprimento da asa anterior (CAA) e largura da asa anterior (LAA), ângulos B4, E9, G18, J16, K19, N23, O26 e distância b (Db); comprimento da asa posterior (CAP) e largura da asa posterior (LAP), distância L2 (DL2), L5 (DL5) e ângulo W3, comprimento do fêmur (CF), comprimento da tíbia (CT), comprimento do tarso (CTS) e largura do tarso (LTS) e comprimento da probóscide (CP). Para a comparação das diferentes variáveis estudadas utilizou-se a análise de variância, o teste de Tukey, análise canônica e o teste de Tocher a 5% de significância. Para as medidas realizadas em cada amostra utilizou-se um equipamento de análise de imagens, Programa Image Pro Plus 4.0. As variáveis CTS e LTS, ângulos G18 e K19 e DL2 diferiram significativamente (p<0,05) entre as localidades estudadas de acordo com o teste de Tukey. A análise canônica mostrou a existência de um agrupamento com base nas características morfológicas entre duas das localidades estudadas apesar da distância geográfica. Concluiu-se que existem dois grupos distintos morfometricamente para a microrregião estudada e que há um processo adaptativo das abelhas, quanto às medidas morfométricas, para as diferentes regiões geomorfológicas

    Tissue Specificity and Dynamics of Sex-Biased Gene Expression in a Common Frog Population with Differentiated, Yet Homomorphic, Sex Chromosomes.

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    Sex-biased genes are central to the study of sexual selection, sexual antagonism, and sex chromosome evolution. We describe a comprehensive de novo assembled transcriptome in the common frog &lt;i&gt;Rana temporaria&lt;/i&gt; based on five developmental stages and three adult tissues from both sexes, obtained from a population with karyotypically homomorphic but genetically differentiated sex chromosomes. This allows the study of sex-biased gene expression throughout development, and its effect on the rate of gene evolution while accounting for pleiotropic expression, which is known to negatively correlate with the evolutionary rate. Overall, sex-biased genes had little overlap among developmental stages and adult tissues. Late developmental stages and gonad tissues had the highest numbers of stage- or tissue-specific genes. We find that pleiotropic gene expression is a better predictor than sex bias for the evolutionary rate of genes, though it often interacts with sex bias. Although genetically differentiated, the sex chromosomes were not enriched in sex-biased genes, possibly due to a very recent arrest of XY recombination. These results extend our understanding of the developmental dynamics, tissue specificity, and genomic localization of sex-biased genes

    Transverse momentum dependence in gluon distribution and fragmentation functions

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    We investigate the twist two gluon distribution functions for spin 1/2 hadrons, emphasizing intrinsic transverse momentum of the gluons. These functions are relevant in leading order in the inverse hard scale in scattering processes such as inclusive leptoproduction or Drell-Yan scattering, or more general in hard processes in which at least two hadrons are involved. They show up in azimuthal asymmetries. For future estimates of such observables, we discuss specific bounds on these functions.Comment: 14 pages, revtex, 7 Postscript figure

    Obesidade e a prevalência da síndrome metabólica, um estudo em crianças e adolescentes madeirenses

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    A obesidade atinge actualmente proporções epidemiológicas, tendo-se vindo a registar um incremento alarmante na população pediátrica. Diversos estudos têm mostrado a existência de um forte vínculo entre a obesidade e a prevalência da Síndrome Metabólica (SM). O presente estudo tem como objectivo central determinar a contribuição do excesso de peso e da obesidade na prevalência da SM em crianças e adolescentes

    Corpo, maturação biológica e actividade física: um olhar interactivo em crianças e jovens madeirenses

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    Cada vez mais a sociedade moderna é olhada através da sua condição física, enquanto factor de bem-estar, saúde, qualidade de vida e longevidade dos seus membros. Os indicadores demográficos actuais da população madeirense apontam no sentido de uma considerável componente juvenil, adolescente e jovem. No entanto, a evolução demográfica prevista, decorrente de um acentuado decréscimo da natalidade, leva a prever um comportamento diverso da pirâmide de idades, assumindo particular ênfase as questões relacionadas com o estudo e a investigação do corpo, a procura de padrões, a descrição normativa, a interpretação das mudanças e o espaço morfológico externo, que se vem enquadrar no território de investigação reservado à somatotipologia

    All-particle cosmic ray energy spectrum measured with 26 IceTop stations

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    We report on a measurement of the cosmic ray energy spectrum with the IceTop air shower array, the surface component of the IceCube Neutrino Observatory at the South Pole. The data used in this analysis were taken between June and October, 2007, with 26 surface stations operational at that time, corresponding to about one third of the final array. The fiducial area used in this analysis was 0.122 km^2. The analysis investigated the energy spectrum from 1 to 100 PeV measured for three different zenith angle ranges between 0{\deg} and 46{\deg}. Because of the isotropy of cosmic rays in this energy range the spectra from all zenith angle intervals have to agree. The cosmic-ray energy spectrum was determined under different assumptions on the primary mass composition. Good agreement of spectra in the three zenith angle ranges was found for the assumption of pure proton and a simple two-component model. For zenith angles {\theta} < 30{\deg}, where the mass dependence is smallest, the knee in the cosmic ray energy spectrum was observed between 3.5 and 4.32 PeV, depending on composition assumption. Spectral indices above the knee range from -3.08 to -3.11 depending on primary mass composition assumption. Moreover, an indication of a flattening of the spectrum above 22 PeV were observed.Comment: 38 pages, 17 figure

    An improved method for measuring muon energy using the truncated mean of dE/dx

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    The measurement of muon energy is critical for many analyses in large Cherenkov detectors, particularly those that involve separating extraterrestrial neutrinos from the atmospheric neutrino background. Muon energy has traditionally been determined by measuring the specific energy loss (dE/dx) along the muon's path and relating the dE/dx to the muon energy. Because high-energy muons (E_mu > 1 TeV) lose energy randomly, the spread in dE/dx values is quite large, leading to a typical energy resolution of 0.29 in log10(E_mu) for a muon observed over a 1 km path length in the IceCube detector. In this paper, we present an improved method that uses a truncated mean and other techniques to determine the muon energy. The muon track is divided into separate segments with individual dE/dx values. The elimination of segments with the highest dE/dx results in an overall dE/dx that is more closely correlated to the muon energy. This method results in an energy resolution of 0.22 in log10(E_mu), which gives a 26% improvement. This technique is applicable to any large water or ice detector and potentially to large scintillator or liquid argon detectors.Comment: 12 pages, 16 figure

    Measurement of the Bs0J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction

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    The Bs0J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction is measured in a data sample corresponding to 0.41fb1fb^{-1} of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2β\beta measurement from B0J/ψKS0B^0\to J/\psi K_S^0 The time-integrated branching fraction is measured to be BF(Bs0J/ψKS0)=(1.83±0.28)×105BF(B_s^0\to J/\psi K_S^0)=(1.83\pm0.28)\times10^{-5}. This is the most precise measurement to date
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