Spin torque contribution to the a.c. spin Hall conductivity

Using the recently proposed definition of a conserved spin-current operator [J. Shi et al., Phys. Rev. Lett. 96, 076604 (2006)] we explore the frequency dependent spin Hall conductivity for a two-dimensional electron gas with Rashba and Dresselhaus spin-orbit interaction in response to an oscillating electric field. We show that the optical spectrum of the spin Hall conductivity exhibit remarkable changes when the new definition of spin current is applied. Such behavior is mainly due to a significant contribution of the spin torque term which is absent in the conventional form of the spin current. In addition, it is observed that the magnitude and direction of the dynamic spin Hall current strongly depends on the electric field frequency as with the interplay of the spin-orbit coupling strengths.Comment: 8 pages, 4 figures, pape

The relationship between gut microbiota and spontaneous bacterial peritonitis in patients with liver cirrhosis - a literature review

Gut microbiota is an essential component in the pathogenesis of liver cirrhosis and its complications. There is a direct relationship between the gut and the liver called the gutliver axis through which bacteria can reach the liver through the portal venous blood. However, it remains unclear how bacteria leave the intestine and reach the fluid collection in the abdomen. A series of mechanisms have been postulated to be involved in the pathogenesis of spontaneous bacterial peritonitis (SBP) and other complications of liver cirrhosis, including bacterial translocation, bacterial overgrowth, altered intestinal permeability and dysfunctional immunity. The hepatic function may also be affected by the alteration of intestinal microbiota composition. Current treatment in SBP is antibiotic therapy, but lately, probiotics have been the useful treatment suggested to improve the intestinal barrier and prevent bacterial translocation. However, studies are contradictory regarding their usefulness. In this review, we will summarize the literature data on the pathogenesis of spontaneous bacterial peritonitis concerning the existence of a relationship with the microbiota and the useful use of probiotics

Global impact of diet and temperature over aquaculture of Octopus vulgaris paralarvae from a transcriptomic approach

Common octopus, Octopus vulgaris, is an economically important cephalopod species. However, its rearing under captivity is currently challenged by massive mortalities previous to their juvenile stage due to nutritional and environmental factors. Dissecting the genetic basis and regulatory mechanism behind this mortality requires genomic background knowledge. A transcriptomic sequencing of 10 dph octopus paralarvae from different experimental conditions was constructed via RNA-seq. A total of 613,767,530 raw reads were filtered and de novo assembled into 363,527 contigs of which 82,513 were annotated in UniProt carrying also their GO and KEGG information. Differential gene expression analysis was carried out on paralarvae reared under different diet regimes and temperatures, also including wild paralarvae. Genes related to lipid metabolism exhibited higher transcriptional levels in individuals whose diet includes crustacean zoeas, which had an impact over their development and immune response capability. High temperature induces acclimation processes at the time that increase metabolic demands and oxidative stress. Wild individuals show an expression profile unexpectedly similar to Artemia fed individuals. Proteomic results support the hypothesis revealed by transcriptional analysis. The comparative study of the O. vulgaris transcriptomic profiles allowed the identification of genes that deserve to be further studied as candidates for biomarkers of development and health. The results obtained here on the transcriptional variations of genes caused by diet and temperature will provide new perspectives in understanding the molecular mechanisms behind nutritional and temperature requirements of common octopus that will open new opportunities to deepen in paralarvae rearing requirements.Versión del edito

Exploring the influence of ancient and historic megaherbivore extirpations on the global methane budget

Globally, large-bodied wild mammals are in peril. Because “megamammals” have a disproportionate influence on vegetation, trophic interactions, and ecosystem function, declining populations are of considerable conservation concern. However, this is not new; trophic downgrading occurred in the past, including the African rinderpest epizootic of the 1890s, the massive Great Plains bison kill-off in the 1860s, and the terminal Pleistocene extinction of megafauna. Examining the consequences of these earlier events yields insights into contemporary ecosystem function. Here, we focus on changes inmethane emissions, produced as a byproduct of enteric fermentation by herbivores. Although methane is ∼200 times less abundant than carbon dioxide in the atmosphere, the greater efficiency of methane in trapping radiation leads to a significant role in radiative forcing of climate. Using global datasets of late Quaternary mammals, domestic livestock, and human population from the United Nations as well as literature sources, we develop a series of allometric regressions relating mammal body mass to population density and CH4 production, which allows estimation of methane production by wild and domestic herbivores for each historic or ancient time period. We find the extirpation ofmegaherbivores reduced global enteric emissions between 2.2–69.6 Tg CH4 y−1 during the various time periods, representing a decrease of 0.8–34.8% of the overall inputs to tropospheric input. Our analyses suggest that large-bodied mammals have a greater influence on methane emissions than previously appreciated and, further, that changes in the source pool from herbivores can influence global biogeochemical cycles and, potentially, climate

ACTN3 R577X Polymorphism does not Influence Explosive Leg Muscle Power in Elite Volleyball Players

We examined the association of R577X polymorphism (rs1815739) in the α-actinin-3 (ACTN3) gene with “explosive” leg muscle power performance in a group of male and female elite volleyball players (n=66, 31 men, 35 women) and in a group of non-athletic male and female young adults (n=334, 243 men, 91 women). We assessed power performance by means of the vertical squat and counter-movement jump tests. We also determined whether the genotypic frequencies of the ACTN3 R577X genotypes differed between groups. We did not observe any effect of the ACTN3 R577X polymorphism on study phenotypes in both groups, regardless of gender (all P>0.05). Genotype frequencies were similar between volleyball and control groups (P=0.095). Moreover, we did not find an association between the ACTN3 R577X polymorphism and the likelihood of being an elite volleyball player using the dominant (RR vs RX+XX) and the recessive model (RR+RX vs XX). In summary, these findings suggest that the ACTN3 R577X polymorphism does not influence explosive leg muscle power in elite volleyball players

Employment Expectations and Gross Flows by Type of Work Contract

There is growing interest in understanding firms’ temporary and permanent employment practices and how institutional changes shape them. Using data on Spanish establishments, we examine: (a) how employers adjust temporary and permanent job and worker flows to prior employment expectations, and (b) how the 1994 and 1997 labour reforms promoting permanent employment affected establishments’ employment practices. Generally, establishments’ prior employment expectations are realized through changes in all job and worker flows. However, establishments uniquely rely on temporary hires as a buffer to confront diminishing long-run employment expectations. None of the reforms significantly affected establishments’ net temporary or permanent employment flows.http://deepblue.lib.umich.edu/bitstream/2027.42/40032/3/wp646.pd

Efficiency of the cerebroplacental ratio in Identifying high-risk late-term pregnancies

Background and Objectives: Over the last few years, great interest has arisen in the role of the cerebroplacental ratio (CPR) to identify low-risk pregnancies at higher risk of adverse pregnancy outcomes. This study aimed to assess the predictive capacity of the CPR for adverse perinatal outcomes in all uncomplicated singleton pregnancies attending an appointment at 40–42 weeks. Materials and Methods: This is a retrospective cohort study including all consecutive singleton pregnancies undergoing a routine prenatal care appointment after 40 weeks in three maternity units in Spain and the United Kingdom from January 2017 to December 2019. The primary outcome was adverse perinatal outcomes defined as stillbirth or neonatal death, cesarean section or instrumental delivery due to fetal distress during labor, umbilical arterial cord blood pH < 7.0, umbilical venous cord blood pH < 7.1, Apgar score at 5 min < 7, and admission to the neonatal unit. Logistic mixed models and ROC curve analyses were used to analyze the data. Results: A total of 3143 pregnancies were analyzed, including 537 (17.1%) with an adverse perinatal outcome. Maternal age (odds ratio (OR) 1.03, 95% confidence interval (CI) 1.01 to 1.04), body mass index (OR 1.04, 95% CI 1.03 to 1.06), racial origin (OR 2.80, 95% CI 1.90 to 4.12), parity (OR 0.36, 95% CI 0.29 to 0.45), and labor induction (OR 1.79, 95% CI 1.36 to 2.35) were significant predictors of adverse perinatal outcomes with an area under the ROC curve of 0.743 (95% CI 0.720 to 0.766). The addition of the CPR to the previous model did not improve performance. Additionally, the CPR alone achieved a detection rate of only 11.9% (95% CI 9.3 to 15) when using the 10th centile as the screen-positive cutoff. Conclusions: Our data on late-term unselected pregnancies suggest that the CPR is a poor predictor of adverse perinatal outcomes