1,246 research outputs found

    Milking procedures, milk flow curves and somatic cell count in dairy cows

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    Recent availability of electronic mobile milk flow meters allows to study in details milk flow patterns during milking. A normal milk flow profile is characterized by an incline phase, with increasing milk flow, a plateau phase, with steady milk flow, and a decline phase. In these phases milk flow is influenced by many factors: genetic characteristics of the cows, regulation of milking machine and milking routine

    A Corte Portuguesa e o Escravismo no Brasil Sob o Olhar de Debret

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    A imagem é uma fonte de investigação que traz em suas estruturas elementos valiosos para a compreensão do período histórico que apresenta. Compreender o caráter histórico imerso nas gravuras elaboradas pelo artista francês Jean Baptiste Debret, no período em que permaneceu no Brasil, que apresentam a corte portuguesa e o negro nas ruas do Rio de Janeiro na primeira metade do século XIX é o objetivo principal desse estudo que utiliza imagens como fonte primordial de análise do período pesquisado. Período marcado por grandes transformações políticas e sócio-culturais geradas pela transferência da Corte portuguesa para o Brasil possibilitando ao artista francês um contexto rico para representações da sociedade carioca. Convidado a compor a Missão Artista Francesa, Debret chega ao Brasil sob o título de pintor de histórica com a incumbência de elaborar a história visual da corte no Brasil e encontra nas ruas da cidade carioca um ambiente favorável para a representação da sociedade que se formara a partir da transferência da família real. Identificando o olhar do artista como narrador dos acontecimentos, através da leitura de imagens, pretende-se garantir à produção de Debret reconhecimento como objeto de comunicação e significação que contém em si elementos historiográficos do Brasil nas primeiras décadas do século XIX. Palavras-chave: Imagem Fonte de pesquisa, história, Semiótica, Debre

    Universal measurability and the Hochschild class of the Chern character

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    We study notions of measurability for singular traces, and characterise universal measurability for operators in Dixmier ideals. This measurability result is then applied to improve on the various proofs of Connes\u27 identification of the Hochschild class of the Chern character of Dixmier summable spectral triples. The measurability results show that the identification of the Hochschild class is independent of the choice of singular trace. As a corollary we obtain strong information on the asymptotics of the eigenvalues of operators naturally associated to spectral triples (A, H, D) and Hochschild cycles for A

    Modeling the evolution of item rating networks using time-domain preferential attachment

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    The understanding of the structure and dynamics of the intricate network of connections among people that consumes products through Internet appears as an extremely useful asset in order to study emergent properties related to social behavior. This knowledge could be useful, for example, to improve the performance of personal recommendation algorithms. In this contribution, we analyzed five-year records of movie-rating transactions provided by Netflix, a movie rental platform where users rate movies from an online catalog. This dataset can be studied as a bipartite user-item network whose structure evolves in time. Even though several topological properties from subsets of this bipartite network have been reported with a model that combines random and preferential attachment mechanisms [Beguerisse Díaz et al., 2010], there are still many aspects worth to be explored, as they are connected to relevant phenomena underlying the evolution of the network. In this work, we test the hypothesis that bursty human behavior is essential in order to describe how a bipartite user-item network evolves in time. To that end, we propose a novel model that combines, for user nodes, a network growth prescription based on a preferential attachment mechanism acting not only in the topological domain (i.e. based on node degrees) but also in time domain. In the case of items, the model mixes degree preferential attachment and random selection. With these ingredients, the model is not only able to reproduce the asymptotic degree distribution, but also shows an excellent agreement with the Netflix data in several time-dependent topological properties

    Effects of the Fractionation of the Nitrogen Fertilization on Root Nitrate Uptake and Vine Agronomic Performance in Pinot Gris Grapevines in a Temperate Climate

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    The study aims to investigate at a physiological and molecular level the root absorption of nitrogen (N) during the annual cycle of grapevine. The study was performed on potted Pinot Gris plants grafted on Kober 5BB and grown for two consecutive years in a semi-controlled environment (Northeast, Italy). The study compared the response of plants N-fertilized in spring (T1), or in spring and in post-harvest (T2) or no-N fertilized (C). Results showed that under our climate conditions nitrate was taken up by the grapevines when applied both in spring or in spring and post-harvest. The nitrate acquisition in T1 roots is mediated at molecular and physiological level by a higher activation of high-affinity nitrate-transport system to take up nitrate in comparison to no-fertilized plants. Comparing the two N fertilization managements, the dynamic of nitrate uptake rates showed different patterns with an overall late response of High-Affinity Transport System when the application of part of N-fertilization was delayed to post-harvest (T2) in comparison to T1. Nevertheless, during the 2 years of the trial the fractionation of N fertilization applied in spring and post-harvest did not negatively affect the yield and quality parameters of vines. An increase of N concentration in T2 roots after two consecutive growing seasons may suggest that the fractionation can lead to beneficial effects on long period. Results of this work contribute to improve the comprehension of N acquisition in grapevine in order to optimize the use of N inputs in vineyard

    Spectrally multimode squeezed states generation at telecom wavelengths

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    We report on the experimental demonstration of a source that generates spectrally multimode squeezed states of light over the infrared C-Band. This is achieved using a single-pass Spontaneous Parametric Down Conversion (SPDC) process in a periodically-poled KTP waveguide that is pumped with the second harmonic of a femtosecond laser. Our measurements show significant squeezing in more than 21 frequency modes, with a maximum squeezing value over 2.5 dB. Moreover, we demonstrate multiparty entanglement across 8 individual frequency bands by measuring the covariance matrix of their quadratures. Finally, we use reconfigurable mode-selective homodyne detection to mold the output into cluster states of various shapes. This result paves the way for the implementation of continuous variable quantum information protocols at telecommunication wavelengths, with applications in multiparty, entanglement-based quantum communication and computation

    Transcriptomic and metabolomic profiles of Zea mays fed with urea and ammonium

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    The simultaneous presence of different N-forms in the rhizosphere leads to beneficial effects on nitrogen (N) nutrition in plants. Although widely used as fertilizers, the occurrence of cross connection between urea and ammonium nutrition has been scarcely studied in plants. Maize fed with a mixture of urea and ammonium displayed a better N-uptake efficiency than ammonium- or urea-fed plants (Buoso et al., Plant Physiol Biochem, 2021a; 162: 613\u2013623). Through multiomic approaches, we provide the molecular characterization of maize response to urea and ammonium nutrition. Several transporters and enzymes involved in N-nutrition were upregulated by all three N-treatments (urea, ammonium, or urea and ammonium). Already after 1 day of treatment, the availability of different N-forms induced specific transcriptomic and metabolomic responses. The combination of urea and ammonium induced a prompt assimilation of N, characterized by high levels of some amino acids in shoots. Moreover, ZmAMT1.1a, ZmGLN1;2, ZmGLN1;5, ZmGOT1, and ZmGOT3, as well transcripts involved in glycolysis-TCA cycle were induced in roots by urea and ammonium mixture. Depending on N-form, even changes in the composition of phytohormones were observed in maize. This study paves the way to formulate guidelines for the optimization of N fertilization to improve N-use efficiency in maize and therefore limit N-losses in the environment
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