Genetic and environmental factors affecting some reproductive traits of Holstein cows in Cuba

International audienc

Signatures of Dark Matter Scattering Inelastically Off Nuclei

Direct dark matter detection focuses on elastic scattering of dark matter particles off nuclei. In this study, we explore inelastic scattering where the nucleus is excited to a low-lying state of 10-100 keV, with subsequent prompt de-excitation. We calculate the inelastic structure factors for the odd-mass xenon isotopes based on state-of-the-art large-scale shell-model calculations with chiral effective field theory WIMP-nucleon currents. For these cases, we find that the inelastic channel is comparable to or can dominate the elastic channel for momentum transfers around 150 MeV. We calculate the inelastic recoil spectra in the standard halo model, compare these to the elastic case, and discuss the expected signatures in a xenon detector, along with implications for existing and future experiments. The combined information from elastic and inelastic scattering will allow to determine the dominant interaction channel within one experiment. In addition, the two channels probe different regions of the dark matter velocity distribution and can provide insight into the dark halo structure. The allowed recoil energy domain and the recoil energy at which the integrated inelastic rates start to dominate the elastic channel depend on the mass of the dark matter particle, thus providing a potential handle to constrain its mass.Comment: 9 pages, 7 figures. Matches resubmitted version to Phys. Rev. D. One figure added; supplemental material (fits to the structure functions) added as an Appendi

Inelastic light scattering and the excited states of many-electron quantum dots

A consistent calculation of resonant inelastic (Raman) scattering amplitudes for relatively large quantum dots, which takes account of valence-band mixing, discrete character of the spectrum in intermediate and final states, and interference effects, is presented. Raman peaks in charge and spin channels are compared with multipole strengths and with the density of energy levels in final states. A qualitative comparison with the available experimental results is given.Comment: 5 pages, accepted in J. Phys.: Condens. Matte

Dynamic Output State Classification for Quantum Computers

Quantum computers promise a potentially disruptive approach to improving computation in fields such as physics, chemistry, cryptography, optimisation, and machine learning. However, testing quantum computations for faults is currently impractical because of the existence of noise and errors associated with the output. Executing in a quantum system a circuit with only a few valid output states can generate a significant number of implausible states that have zero probability in an ideal computation. Among other sources of noise, readout errors come from the difficulty of discriminating a measurement between 0 and 1 for the different qubits. These issues are affected by readout drift, requiring regular recalibration of the process. In this paper, we provide a novel technique for post-computation analysis of the output probability distributions that permits better discrimination of kerneled data, delaying the need for recalibration. We achieve this by altering the linear discrimination of the final output states by way of a dynamic state selection process that combines Gaussian mixture models with a probability threshold. As an initial assessment of the technique we examine its effect on three to five qubits GHZ states. Our results on almost every one of nine IBM quantum computers show that the number of implausible states is reduced significantly and that the resulting probability distribution is closer to the expected one

Spontaneous collapse models lead to the emergence of classicality of the Universe

Assuming that Quantum Mechanics is universal and that it can be applied over all scales, then the Universe is allowed to be in a quantum superposition of states, where each of them can correspond to a different space-time geometry. How can one then describe the emergence of the classical, well-defined geometry that we observe? Considering that the decoherence-driven quantum-to-classical transition relies on external physical entities, this process cannot account for the emergence of the classical behaviour of the Universe. Here, we show how models of spontaneous collapse of the wavefunction can offer a viable mechanism for explaining such an emergence. We apply it to a simple General Relativity dynamical model for gravity and a perfect fluid. We show that, by starting from a general quantum superposition of different geometries, the collapse dynamics leads to a single geometry, thus providing a possible mechanism for the quantum-to-classical transition of the Universe. Similarly, when applying our dynamics to the physically-equivalent Parametrised Unimodular gravity model, we obtain a collapse on the basis of the cosmological constant, where eventually one precise value is selected, thus providing also a viable explanation for the cosmological constant problem. Our formalism can be easily applied to other quantum cosmological models where we can choose a well-defined clock variable

The Implementation of Positive Behavioral Support in an Elementary School: Processes, Procedures, and Outcomes

This article presents the processes and outcomes of a year of School-Wide Positive Behavior Support in a North Texas elementary school serving kindergarten through grade 3 students. Included is a description of a school treatment package that incorporated components such as facilitation of the teaming process, a lottery-type system of intermittent reinforcement, mystery motivators, and recognition assemblies, all targeted at increased student compliance with school rules. Positive outcomes included: (a) a reduction in the number of office referrals; (b) reduced frequency of rules-based violations on the part of students; (c) reduced use of punitive consequences such as time-outs, written reprimands, and student conferences on the part of the faculty and administration; and (d) an increase in scores on a state-mandated academic achievement assessment administered to grade 3 students.Cet article présente les processus et les résultats découlant de la mise en application, pendant une année, d’un programme de gestion de classe et d’école pour contrer l’indiscipline et les conflits (SchoolWide Positive Behavior Support) dans une école primaire (maternelle-troisième) dans le nord du Texas. Nous décrivons le programme et ses composantes telles la facilitation du processus de formation d’équipes, un système ressemblant à un jeu de loterie et visant le renforcement intermittent, des facteurs motivants «mystères» et des rencontres de reconnaissance du mérite – le tout pour stimuler chez les élèves un comportement conforme aux règlements de l’école. Parmi les résultats positifs, notons : (a) une diminution du nombre d’élèves envoyés à la direction; (b) une diminution de la fréquence des infractions; (c) une diminution de l’emploi des punitions telles la suspension de renforcement, les réprimandes écrites et les conférences entre les élèves et le personnel enseignant et l’administration; et (d) une hausse des scores obtenus par les élèves en 3e aux évaluations d’état du rendement académique

A linear domain decomposition method for two-phase flow in porous media

This article is a follow up of our submitted paper [11] in which a decomposition of the Richards equation along two soil layers was discussed. A decomposed problem was formulated and a decoupling and linearisation technique was presented to solve the problem in each time step in a fixed point type iteration. This article extends these ideas to the case of two-phase in porous media and the convergence of the proposed domain decomposition method is rigorously shown.Comment: 8 page