1,137 research outputs found

    The Radial Distribution of Dust Particles in the HL Tau Disk from ALMA and VLA Observations

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    Understanding planet formation requires one to discern how dust grows in protoplanetary disks. An important parameter to measure in disks is the maximum dust grain size present. This is usually estimated through measurements of the dust opacity at different millimeter wavelengths assuming optically thin emission and dust opacity dominated by absorption. However, Atacama Large Millimeter/submillimeter Array (ALMA) observations have shown that these assumptions might not be correct in the case of protoplanetary disks, leading to overestimation of particle sizes and to underestimation of the disk\u27s mass. Here, we present an analysis of high-quality ALMA and Very Large Array images of the HL Tau protoplanetary disk, covering a wide range of wavelengths, from 0.8 mm to 1 cm, and with a physical resolution of ~7.35 au. We describe a procedure to analyze a set of millimeter images without any assumption about the optical depth of the emission, and including the effects of absorption and scattering in the dust opacity. This procedure allows us to obtain the dust temperature, the dust surface density, and the maximum particle size at each radius. In the HL Tau disk, we found that particles have already grown to a few millimeters in size. We detect differences in the dust properties between dark and bright rings, with dark rings containing low dust density and small dust particles. Different features in the HL Tau disk seem to have different origins. Planet–disk interactions can explain substructure in the external half of the disk, but the internal rings seem to be associated with the presence of snow lines of several molecules

    The VLA view of the HL Tau Disk - Disk Mass, Grain Evolution, and Early Planet Formation

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    The first long-baseline ALMA campaign resolved the disk around the young star HL Tau into a number of axisymmetric bright and dark rings. Despite the very young age of HL Tau these structures have been interpreted as signatures for the presence of (proto)planets. The ALMA images triggered numerous theoretical studies based on disk-planet interactions, magnetically driven disk structures, and grain evolution. Of special interest are the inner parts of disks, where terrestrial planets are expected to form. However, the emission from these regions in HL Tau turned out to be optically thick at all ALMA wavelengths, preventing the derivation of surface density profiles and grain size distributions. Here, we present the most sensitive images of HL Tau obtained to date with the Karl G. Jansky Very Large Array at 7.0 mm wavelength with a spatial resolution comparable to the ALMA images. At this long wavelength the dust emission from HL Tau is optically thin, allowing a comprehensive study of the inner disk. We obtain a total disk dust mass of 0.001 - 0.003 Msun, depending on the assumed opacity and disk temperature. Our optically thin data also indicate fast grain growth, fragmentation, and formation of dense clumps in the inner densest parts of the disk. Our results suggest that the HL Tau disk may be actually in a very early stage of planetary formation, with planets not already formed in the gaps but in the process of future formation in the bright rings.Comment: Accepted by The Astrophysical Journal Letter

    Productive and reproductive performance of dual-purpose cows in two systems of suckling in the tropics

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    With the objective of finding an alternative management to improve the reproductive and productive efficiencyof dual-purpose Bos taurus x Bos indicus cows in a tropical environment, 20 adult, ¾ Brown Swiss x ¼ Cebu cows were assigned to two treatments: traditional suckling (AT; n = 10) and delayed suckling (AR; n = 10). In AT, three quarters were milked mechanically and one quarter was left for the calf; after milking, the calf remained with its mother for 7 h. Cows in AR were milked completely and a suckling period of 1 h took place 8 h after milking. Estrus was detected twice daily, with the help of a bull with a deviated penis. Milk production and liveweight of the calves and cows were recorded every 7 and 15 days, respectively. Statistical analysis utilized the t-test for samples of independent populations; a model of fixed effects without interaction, with suckling management and number of parturition as the principal effects; and Chi-square. The number of cows observed in estrus was greater (P<.05) in AR (90%) than in AT (70%). Use of AR reduced by 11 d the interval from parturition to first estrus (69.9 ± 24.7 vs. 58.4 ± 23.6). No differences (P>.05) were found in rate of weight gain of the calves (637 ± 200 vs. 724 ± 100 g/d), in milk obtained mechanically (4.4 ± 1.5 vs. 5.1 ± 1.3 kg/d), or in liveweight change of the dams (-0.221 ± 0.2 vs -0.115 ± 0.3 kg/d) between AT and AR, respectively. Total milk production in AR exceeded (P<.05) that in AT (11.3 ± 1.6 vs. 9.4 ± 2.0 kg/d). It is concluded that delaying suckling for 8 h after milking benefits the interval from parturition to first estrus, the proportion of cows ovulating and milk production during the first 100 d postpartum, without adversely affecting calf growth, liveweight of the cow, and milk extracted mechanically

    Exploring deep learning for complex trait genomic prediction in polyploid outcrossing species

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    Genomic prediction (GP) is the procedure whereby the genetic merits of untested candidates are predicted using genome wide marker information. Although numerous examples of GP exist in plants and animals, applications to polyploid organisms are still scarce, partly due to limited genome resources and the complexity of this system. Deep learning (DL) techniques comprise a heterogeneous collection of machine learning algorithms that have excelled at many prediction tasks. A potential advantage of DL for GP over standard linear model methods is that DL can potentially take into account all genetic interactions, including dominance and epistasis, which are expected to be of special relevance in most polyploids. In this study, we evaluated the predictive accuracy of linear and DL techniques in two important small fruits or berries: strawberry and blueberry. The two datasets contained a total of 1,358 allopolyploid strawberry (2n=8x=112) and 1,802 autopolyploid blueberry (2n=4x=48) individuals, genotyped for 9,908 and 73,045 single nucleotide polymorphism (SNP) markers, respectively, and phenotyped for five agronomic traits each. DL depends on numerous parameters that influence performance and optimizing hyperparameter values can be a critical step. Here we show that interactions between hyperparameter combinations should be expected and that the number of convolutional filters and regularization in the first layers can have an important effect on model performance. In terms of genomic prediction, we did not find an advantage of DL over linear model methods, except when the epistasis component was important. Linear Bayesian models were better than convolutional neural networks for the full additive architecture, whereas the opposite was observed under strong epistasis. However, by using a parameterization capable of taking into account these non-linear effects, Bayesian linear models can match or exceed the predictive accuracy of DL. A semiautomatic implementation of the DL pipeline is available at https://github.com/lauzingaretti/deepGP/

    Cost-Utility of Mindfulness-Based Stress Reduction for Fibromyalgia versus a Multicomponent Intervention and Usual Care: A 12-Month Randomized Controlled Trial (EUDAIMON Study)

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    Fibromyalgia (FM) is a prevalent, chronic, disabling, pain syndrome that implies high healthcare costs. Economic evaluations of potentially effective treatments for FM are needed. The aim of this study was to analyze the cost-utility of Mindfulness-Based Stress Reduction (MBSR) as an add-on to treatment-as-usual (TAU) for patients with FM compared to an adjuvant multicomponent intervention (FibroQoL) and to TAU. We performed an economic evaluation alongside a 12 month, randomized, controlled trial; data from 204 (68 per study arm) of the 225 patients (90.1%) were included in the cost-utility analyses, which were conducted both under the government and the public healthcare system perspectives. The main outcome measures were the EuroQol (EQ-5D-5L) for assessing Quality-Adjusted Life Years (QALYs) and improvements in health-related quality of life, and the Client Service Receipt Inventory (CSRI) for estimating direct and indirect costs. Incremental cost-effectiveness ratios (ICERs) were also calculated. Two sensitivity analyses (intention-to-treat, ITT, and per protocol, PPA) were conducted. The results indicated that MBSR achieved a significant reduction in costs compared to the other study arms (p < 0.05 in the completers sample), especially in terms of indirect costs and primary healthcare services. It also produced a significant incremental effect compared to TAU in the ITT sample (Delta QALYs = 0.053, p < 0.05, where QALYs represents quality-adjusted life years). Overall, our findings support the efficiency of MBSR over FibroQoL and TAU specifically within a Spanish public healthcare context

    Auxiliary variables for Bayesian inference in multi-class queueing networks

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    Queueing networks describe complex stochastic systems of both theoretical and practical interest. They provide the means to assess alterations, diagnose poor performance and evaluate robustness across sets of interconnected resources. In the present paper, we focus on the underlying continuous-time Markov chains induced by these networks, and we present a flexible method for drawing parameter inference in multi-class Markovian cases with switching and different service disciplines. The approach is directed towards the inferential problem with missing data, where transition paths of individual tasks among the queues are often unknown. The paper introduces a slice sampling technique with mappings to the measurable space of task transitions between the service stations. This can address time and tractability issues in computational procedures, handle prior system knowledge and overcome common restrictions on service rates across existing inferential frameworks. Finally, the proposed algorithm is validated on synthetic data and applied to a real data set, obtained from a service delivery tasking tool implemented in two university hospitals

    Study of BDKπ+πB^{-}\to DK^-\pi^+\pi^- and BDππ+πB^-\to D\pi^-\pi^+\pi^- decays and determination of the CKM angle γ\gamma

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    We report a study of the suppressed BDKπ+πB^-\to DK^-\pi^+\pi^- and favored BDππ+πB^-\to D\pi^-\pi^+\pi^- decays, where the neutral DD meson is detected through its decays to the Kπ±K^{\mp}\pi^{\pm} and CP-even K+KK^+K^- and π+π\pi^+\pi^- final states. The measurement is carried out using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 3.0~fb1^{-1}. We observe the first significant signals in the CP-even final states of the DD meson for both the suppressed BDKπ+πB^-\to DK^-\pi^+\pi^- and favored BDππ+πB^-\to D\pi^-\pi^+\pi^- modes, as well as in the doubly Cabibbo-suppressed DK+πD\to K^+\pi^- final state of the BDππ+πB^-\to D\pi^-\pi^+\pi^- decay. Evidence for the ADS suppressed decay BDKπ+πB^{-}\to DK^-\pi^+\pi^-, with DK+πD\to K^+\pi^-, is also presented. From the observed yields in the BDKπ+πB^-\to DK^-\pi^+\pi^-, BDππ+πB^-\to D\pi^-\pi^+\pi^- and their charge conjugate decay modes, we measure the value of the weak phase to be γ=(7419+20)o\gamma=(74^{+20}_{-19})^{\rm o}. This is one of the most precise single-measurement determinations of γ\gamma to date.Comment: 22 pages, 9 figures; All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-020.htm

    Quantum numbers of the X(3872)X(3872) state and orbital angular momentum in its ρ0Jψ\rho^0 J\psi decay

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    Angular correlations in B+X(3872)K+B^+\to X(3872) K^+ decays, with X(3872)ρ0J/ψX(3872)\to \rho^0 J/\psi, ρ0π+π\rho^0\to\pi^+\pi^- and J/ψμ+μJ/\psi \to\mu^+\mu^-, are used to measure orbital angular momentum contributions and to determine the JPCJ^{PC} value of the X(3872)X(3872) meson. The data correspond to an integrated luminosity of 3.0 fb1^{-1} of proton-proton collisions collected with the LHCb detector. This determination, for the first time performed without assuming a value for the orbital angular momentum, confirms the quantum numbers to be JPC=1++J^{PC}=1^{++}. The X(3872)X(3872) is found to decay predominantly through S wave and an upper limit of 4%4\% at 95%95\% C.L. is set on the fraction of D wave.Comment: 16 pages, 4 figure

    Differential branching fraction and angular analysis of Λb0Λμ+μ\Lambda^{0}_{b} \rightarrow \Lambda \mu^+\mu^- decays

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    The differential branching fraction of the rare decay Λb0Λμ+μ\Lambda^{0}_{b} \rightarrow \Lambda \mu^+\mu^- is measured as a function of q2q^{2}, the square of the dimuon invariant mass. The analysis is performed using proton-proton collision data, corresponding to an integrated luminosity of 3.0 \mbox{ fb}^{-1}, collected by the LHCb experiment. Evidence of signal is observed in the q2q^2 region below the square of the J/ψJ/\psi mass. Integrating over 15 < q^{2} < 20 \mbox{ GeV}^2/c^4 the branching fraction is measured as d\mathcal{B}(\Lambda^{0}_{b} \rightarrow \Lambda \mu^+\mu^-)/dq^2 = (1.18 ^{+ 0.09} _{-0.08} \pm 0.03 \pm 0.27) \times 10^{-7} ( \mbox{GeV}^{2}/c^{4})^{-1}, where the uncertainties are statistical, systematic and due to the normalisation mode, Λb0J/ψΛ\Lambda^{0}_{b} \rightarrow J/\psi \Lambda, respectively. In the q2q^2 intervals where the signal is observed, angular distributions are studied and the forward-backward asymmetries in the dimuon (AFBlA^{l}_{\rm FB}) and hadron (AFBhA^{h}_{\rm FB}) systems are measured for the first time. In the range 15 < q^2 < 20 \mbox{ GeV}^2/c^4 they are found to be A^{l}_{\rm FB} = -0.05 \pm 0.09 \mbox{ (stat)} \pm 0.03 \mbox{ (syst)} and A^{h}_{\rm FB} = -0.29 \pm 0.07 \mbox{ (stat)} \pm 0.03 \mbox{ (syst)}.Comment: 27 pages, 10 figures, Erratum adde

    Measurement of the branching fraction ratio B(Bc+ψ(2S)π+)/B(Bc+J/ψπ+)\mathcal{B}(B_c^+ \rightarrow \psi(2S)\pi^+)/\mathcal{B}(B_c^+ \rightarrow J/\psi \pi^+)

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    Using pppp collision data collected by LHCb at center-of-mass energies s\sqrt{s} = 7 TeV and 8 TeV, corresponding to an integrated luminosity of 3 fb1^{-1}, the ratio of the branching fraction of the Bc+ψ(2S)π+B_c^+ \rightarrow \psi(2S)\pi^+ decay relative to that of the Bc+J/ψπ+B_c^+ \rightarrow J/\psi\pi^+ decay is measured to be 0.268 ±\pm 0.032 (stat) ±\pm 0.007 (syst) ±\pm 0.006 (BF). The first uncertainty is statistical, the second is systematic, and the third is due to the uncertainties on the branching fractions of the J/ψμ+μJ/\psi \rightarrow \mu^+\mu^- and ψ(2S)μ+μ\psi(2S) \rightarrow \mu^+\mu^- decays. This measurement is consistent with the previous LHCb result, and the statistical uncertainty is halved.Comment: 17 pages including author list, 2 figure
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