Nonequilibrium dynamics of spin-boson models from phase space methods

An accurate description of the nonequilibrium dynamics of systems with coupled spin and bosonic degrees of freedom remains theoretically challenging, especially for large system sizes and in higher than one dimension. Phase space methods such as the Truncated Wigner Approximation (TWA) have the advantage of being easily scalable and applicable to arbitrary dimensions. In this work we adapt the TWA to generic spin-boson models by making use of recently developed algorithms for discrete phase spaces [Schachenmayer, PRX 5, 011022 (2015)]. Furthermore we go beyond the standard TWA approximation by applying a scheme based on the Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy of equations [Pucci, PRB 93, 174302 (2016)] to our coupled spin-boson model. This allows in principle to study how systematically adding higher order corrections improves the convergence of the method. To test various levels of approximation we study an exactly solvable spin-boson model which is particularly relevant for trapped-ion arrays. Using TWA and its BBGKY extension we accurately reproduce the time evolution of a number of one- and two-point correlation functions in several dimensions and for arbitrary number of bosonic modes.Comment: 10+5 pages, 5 figure

Editorial: Factors Influencing Biomarker Range Intervals in Farm Animals

A wide variety of biomarkers are used in farm animals for different purposes such as diagnostic testing, animal health monitoring, and serological surveillance and management of a farm. However, the presence of non-pathologic factors represents a challenge for valid and reliable biomarker use. These factors will influence reference interval (RI) and interpretation of biomarker test results. They are defined by intra-species genetic variability, and different physiological and environmental conditions, and their impact might be biological and/or analytical. In this special issue, our contributors have addressed some of the problems related with these factors. Harmonization of veterinary biomarker calibration procedures and reagents is also a must for the rationale use of biomarkers, as pointed out in one of the articles. Yu et al. studied the effects of several variables on the serum biochemical RIs in young animals: age, season of birth and sex in calves and age and sex in piglets. The study comprised unweaned calves (at 24 h and 2, 5, and 7 weeks of age) and piglets from weaning at 21 days old to 35 days of life. In calves, season of birth did not affect the distribution of values of the studied analytes while age-biased differences were noticed. The authors showed that hepatic enzymes, renal markers, antioxidant enzymes (glutatione..

Laser Peening Induced Shock Waves and Cavitation Bubbles in Water Studied by Optical Schlieren Visualization

AbstractA temporal and spatial study of the dynamics of generated shock waves and cavitation bubbles in water by laser peening using nanosecond Nd:YAG laser pulses is reported. False schlieren photographs of the zone surrounding the laser spot on the target were recorded by a fast ICCD camera. The developed experimental setup allowed us to obtain a visualization of the different phenomena (hemispherical, cylindrical and plane shock fronts, cavitation bubbles, phase disturbance tracks, plasma formation, etc.) that occur after the arrival of the laser pulse and that contain valuable information about the mechanical processes that take place on the sample

Refrigerant maldistribution in brazed plate heat exchanger evaporators. Part A: Testing campaign and experimental results

[EN] The refrigerant distribution in a brazed plate heat exchanger evaporator with distributor has been studied with a thermographic camera working under different conditions of inlet vapor quality, superheat, and water temperature drop. The thermographies have shown a clear uneven thermal distribution except when superheat is null. In most of the cases, they show that a great part of the liquid accumulates at the end channels of the evaporator. The degradation of the evaporator performance is higher when the water temperature drop has a similar or higher value than the superheat. On the other hand, when the superheat is significantly higher than the water temperature drop, the evaporator performance is very similar to situations in which there is an even distribution of the refrigerant. The registered evaporation temperatures are much lower for the case of 13 K of water temperature drop, highlighting the importance of the influence of this parameter on the evaporator performance. This research is described in two parts, Part A (present paper) including the description of the experimental campaign, the obtained experimental results and the results discussion and Part B including an analysis of the degradation of the evaporation temperature due to the refrigerant maldistribution as well as a deeper analysis of the registered temperatures and of the causes for the great degradation observed when the water temperature drop is increased.The authors would like to acknowledge the Spanish `Ministerio de Economia Y Competitividad', through the project "Maximizacion de la Eficiencia Y Minimizacion del Impacto Ambiental de Bombas de Calor Para la Descarbonizacion de la Calefaccion/ACS en los Edificios de Consumo Casi Nulo" with the reference ENE2017-83665C2-1-P for the given support.Navarro-Peris, E.; Álvarez Piñeiro, L.; Albaladejo, P.; Schnabel, L.; Corberán, JM. (2021). Refrigerant maldistribution in brazed plate heat exchanger evaporators. Part A: Testing campaign and experimental results. International Journal of Refrigeration. 131:119-128. https://doi.org/10.1016/j.ijrefrig.2021.04.00211912813

Biomechanical analysis of the penalty-corner drag-flick of elite male and female hockey players

The aim of this study was to analyse the kinematic sequencing in the penalty-corner drag-flicks of elite male and female field hockey players of international calibre. Thirteen participants (one skilled male drag-flicker and six male and six female elite players) participated in the study. An optoelectronic motion analysis system was used to capture the drag-flicks with six cameras, sampling at 250 Hz. Select ground reaction force parameters were obtained from a force platform which registered the last support of the front foot. Twenty trials were captured from each subject. Both player groups showed significantly (p < 0.05) smaller ball velocity at release, peak angular velocity of the pelvis, and negative and positive peak angular velocities of the stick than the skilled subject. Normalised ground reaction forces of the gender groups were also smaller than that of the skilled drag-flicker. By comparing these players we established that the cues of the skill level are a wide stance, a whipping action (rapid back lift) of the stick followed by an explosive sequential movement of the pelvis, upper trunk and stick

Library of high and mid-resolution spectra in the CaII H & K, Hα, Hβ, NaI D_1, D_2, and HeI D3 line regions of F, G, K and M field stars

In this work we present spectroscopic observations centered in the spectral lines most widely used as optical indicators of chromospheric activity (Hα, Hβ, CaII H & K, and HeI D_3) in a sample of F, G, K and M chromospherically inactive stars. The spectra have been obtained with the aim of providing a library of high and mid-resolution spectra to be used in the application of the spectral subtraction technique to obtain the active-chromosphere contribution to these lines in chromospherically active single and binary stars. This library can also be used for spectral classification purposes. A digital version with all the spectra is available via ftp and the World Wide Web (WWW) in both ASCII and FITS formats

Acute-phase inter-alpha-trypsin inhibitor heavy chain 4 levels in serum and milk of cows with subclinical mastitis caused by Streptococcus species and coagulase-negative Staphylococcus species

The aim of the study was to investigate the concentrations of acute-phase inter-a-trypsin inhibitor heavy chain 4 (ITIH4) in serum and milk of cows with subclinical mastitis caused by Streptococcus sp. (STR) and coagulase-negative Staphylococcus sp. (CNS) and healthy cows. The blood and milk samples were obtained from 60 mid-lactation, multiparous Holstein-Friesian cows from 7 herds in the Lublin region of Poland. In the milk samples from 40 cows with subclinical mastitis, Streptococcus sp. and CNS were isolated. The ITIH4 was significantly higher in serum of cows with subclinical mastitis caused both by STR and CNS compared with healthy cows. One hundred percent of animals infected with Streptococcus sp. and 89% of animals infected with Staphylococcus sp. showed ITIH4 concentration in sera higher than 0.5 mg/mL. The concentration of ITIH4 in milk also was significantly higher in cows with subclinical mastitis caused by Streptococcus sp. and Staphylococcus sp. compared with the control group. Seventy percent of cows infected by STR and CNS showed ITIH4 concentration in milk higher than 2.5 µg/mL. Milk ITIH4 concentration higher than 5 µg/mL was found in 55% of animals infected with Streptococcus sp. and in 40% of animals infected with Staphylococcus sp. No statistically significant differences were observed in ITIH4 concentrations both in serum and in milk between the studied unhealthy animal groups. These results suggest that ITIH4 may be used in the future as a novel diagnostic marker in serum and in milk of subclinical mastitis in cows

Indirect Encoding Evolutionary Learning Algorithm for the Multilayer Morphological Perceptron

Abstract This article describes an indirectly encoded evolutionary learning algorithm to train morphological neural networks. The indirect encoding method is an algorithm in which the training of the neural network is done by finding the solution without considering the exact connectivity of the network. Looking for the set of weights and architecture in a reduced search space, this simple, but powerful training algorithm is able to evolve to a feasible solution using up to three layers required to perform the pattern classification. This type of representation provides the necessary compactness required by large networks. The algorithm was tested using Iris Fisher data and a prototype was written using Matlab

Synthesis of β‐ 3 H‐mitotane for use in a rapid assay for mitotane metabolism

A 3 H + ‐release method has been developed for the assay of β‐hydroxylation of the adrenolytic drug mitotane. β‐ 3 H‐mitotane was synthesized by the reduction of 1‐(2‐chlorophenyl)‐1‐(4‐chlorophenyl)‐2,2,2‐trichloroethane by an aluminium‐Hg 2 Cl 2 couple in the presence of 3 H 2 O. For β‐hydroxylation of mitotane, the 3 H + ‐release assay is more efficient and sensitive than a method utilizing 14 C‐mitotane and chromatographic separation of metabolites by HPLC. The 3 H + ‐release assay has been used to evaluate the ability of adrenal tumors to metabolize mitotane via the β‐ hydroxylation route.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90382/1/2580360204_ftp.pd