The NAD(P)H-utilizing glutamate dehydrogenase of Bacteroides thetaiotamicron belongs to enzyme family I, and its activity is affected by trans-acting gene(s) positioned downstream of gdhA

Previous studies have suggested that regulation of the enzymes of ammonia assimilation in human colonic Bacteroides species is coordinated differently than in other eubacteria. The gene encoding an NAD(P)H-dependent glutamate dehydrogenase (gdhA) in Bacteroides thetaiotaomicron was tinned and expressed in Escherichia coli by mutant complementation from the recombinant plasmid pANS100. Examination of the predicted GdhA amino acid sequence revealed that this enzyme possesses motifs typical of the family I-type hexameric GDH proteins. Northern blot analysis with a gdhA-specific probe indicated that a single transcript with an electrophoretic mobility of ~1.6 kb was produced in both B. thetaiotaomicron and E. coli gdhA transformants. Although gdhA transcription was unaffected, no GdhA enzyme activity could be detected in E. coli transformants when smaller DNA fragments from pANS100, which contained the entire gdhA gene, were analyzed. Enzyme activity was restored if these E. coli strains were cotransformed with a second plasmid, which contained a 3-kb segment of DNA located downstream of the gdhA coding region. Frameshift mutagenesis within the DNA downstream of gdhA in pANS100 also resulted in the loss of GdhA enzyme activity. Collectively, these results are interpreted as evidence for the role of an additional gene product(s) in modulating the activity of GDH enzyme activity. Insertional mutagenesis experiments which led to disruption of the gdhA gene on the B. thetaiotaomicron chromosome indicated that gdhA mutants were not glutamate auxotrophs, but attempts to isolate similar mutants with insertion mutations in the region downstream of the gdhA gene were unsuccessful

Decoding a Three-Dimensional Conformal Manifold

We study the one-dimensional complex conformal manifold that controls the infrared dynamics of a three-dimensional $\mathcal{N}=2$ supersymmetric theory of three chiral superfields with a cubic superpotential. Two special points on this conformal manifold are the well-known XYZ model and three decoupled copies of the critical Wess-Zumino model. The conformal manifold enjoys a discrete duality group isomorphic to $S_4$ and can be thought of as an orbifold of $\mathbf{CP}^1$. We use the $4-\varepsilon$ expansion and the numerical conformal bootstrap to calculate the spectrum of conformal dimensions of low-lying operators and their OPE coefficients, and find a very good quantitative agreement between the two approaches.Comment: 59 pages, 13 figure

Subthreshold problem drinkers in DSM-5 alcohol use disorder classification.

The DSM-5 defined alcohol use disorder (AUD) to better cover undiagnosed subthreshold alcohol users, but few studies have investigated this topic. This study aimed to test whether subthreshold problem drinkers were a distinct subgroup of undiagnosed drinkers according to the DSM-5 AUD classification by investigating drinking patterns and longitudinal trajectories. Data were collected in the Cohort Study on Substance Use Risk Factors from young Swiss men in their early twenties (n = 4,630) at two time points. Participants responded to the 11 criteria of the DSM-5 AUD and to variables related to drinking patterns. Among drinkers, 23.2% and 23.5% of the participants were subthreshold problem drinkers at baseline and follow-up, respectively. The trends showed that 29.4% of them remained subthreshold problem drinkers over time. Those who remained subthreshold problem drinkers or progressed to AUD status were likely to meet the same criterion/add a new one. Subthreshold problem drinkers showed concurrent and later drinking patterns that were in between those of symptom-free drinkers and AUD drinkers. Subthreshold problem drinkers were an important subgroup of drinkers with risky drinking patterns, but they did not necessarily progress to later AUD status and did not appear to be a consistent subgroup over time. Subthreshold problem drinkers did not seem to be a subgroup of undiagnosed problem drinkers in the current DSM-5 classification. The results showed that AUD appeared to be a dimensional construct, in which one additional criterion was associated with worse alcohol-related outcomes. (Am J Addict 2016;25:408-415)

Dynamics and stability of vortex-antivortex fronts in type II superconductors

The dynamics of vortices in type II superconductors exhibit a variety of patterns whose origin is poorly understood. This is partly due to the nonlinearity of the vortex mobility which gives rise to singular behavior in the vortex densities. Such singular behavior complicates the application of standard linear stability analysis. In this paper, as a first step towards dealing with these dynamical phenomena, we analyze the dynamical stability of a front between vortices and antivortices. In particular we focus on the question of whether an instability of the vortex front can occur in the absence of a coupling to the temperature. Borrowing ideas developed for singular bacterial growth fronts, we perform an explicit linear stability analysis which shows that, for sufficiently large front velocities and in the absence of coupling to the temperature, such vortex fronts are stable even in the presence of in-plane anisotropy. This result differs from previous conclusions drawn on the basis of approximate calculations for stationary fronts. As our method extends to more complicated models, which could include coupling to the temperature or to other fields, it provides the basis for a more systematic stability analysis of nonlinear vortex front dynamics.Comment: 13 pages, 8 figure

Training-induced inversion of spontaneous exchange bias field on La1.5Ca0.5CoMnO6

In this work we report the synthesis and structural, electronic and magnetic properties of La1.5Ca0.5CoMnO6 double-perovskite. This is a re-entrant spin cluster material which exhibits a non-negligible negative exchange bias effect when it is cooled in zero magnetic field from an unmagnetized state down to low temperature. X-ray powder diffraction, X-ray photoelectron spectroscopy and magnetometry results indicate mixed valence state at Co site, leading to competing magnetic phases and uncompensated spins at the magnetic interfaces. We compare the results for this Ca-doped material with those reported for the resemblant compound La1.5Sr0.5CoMnO6, and discuss the much smaller spontaneous exchange bias effect observed for the former in terms of its structural and magnetic particularities. For La1.5Ca0.5CoMnO6, when successive magnetization loops are carried, the spontaneous exchange bias field inverts its sign from negative to positive from the first to the second measurement. We discuss this behavior based on the disorder at the magnetic interfaces, related to the presence of a glassy phase. This compound also exhibits a large conventional exchange bias, for which there is no sign inversion of the exchange bias field for consecutive cycles

Produção de plantas medicinais em sistemas agroflorestais: resultados preliminares de pesquisas participativas com agricultores familiares.

bitstream/item/41998/1/CT0070.pd

Substance Use in Young Swiss Men: The Interplay of Perceived Social Support and Dispositional Characteristics.

Social environment plays a central role in substance use behaviors. However, it is not clear whether its role varies as a function of individual dispositional characteristics. To investigate the interaction between dispositional characteristics (i.e. sensation seeking, anxiety/neuroticism) and social environment (i.e. perceived social support [PSS]) in association with substance use. A representative sample of 5,377 young Swiss males completed a questionnaire assessing substance use, sensation seeking, anxiety/neuroticism, and PSS from friends and from a significant other. Sensation seeking and anxiety/neuroticism were positively related to most substance use outcomes. PSS from friends was significantly and positively related to most alcohol and cannabis use outcomes, and significantly and negatively associated with the use of hard drugs. PSS from a significant other was significantly and negatively associated with most alcohol and cannabis use outcomes. The associations of sensation seeking with drinking volume, alcohol use disorder and the use of illicit drugs other than cannabis were stronger in individuals reporting high levels of PSS from friends than those with low levels. The associations of sensation seeking with risky single-occasion drinking and the use of hard drugs were weaker in participants reporting high levels of PSS from a significant other than in those with low levels. Sensation seeking and anxiety/neuroticism may constitute risk factors for substance use and misuse. PSS from friends may amplify the risk for alcohol and illicit drug use (other than cannabis) associated with high sensation seeking, whereas the PSS from a significant other may reduce it

Compensation temperatures and exchange bias in La1.5Ca0.5CoIrO6

We report on the study of magnetic properties of the La1.5Ca0.5CoIrO6 double perovskite. Via ac magnetic susceptibility we have observed evidence of weak ferromagnetism and reentrant spin glass behavior on an antiferromagnetic matrix. Regarding the magnetic behavior as a function of temperature, we have found that the material displays up to three inversions of its magnetization, depending on the appropriate choice of the applied magnetic field. At low temperature the material exhibit exchange bias effect when it is cooled in the presence of a magnetic field. Also, our results indicate that this effect may be observed even when the system is cooled at zero field. Supported by other measurements and also by electronic structure calculations, we discuss the magnetic reversals and spontaneous exchange bias effect in terms of magnetic phase separation and magnetic frustration of Ir4+ ions located between the antiferromagnetically coupled Co ions.Comment: 10 pages, 8 figures and supplemental materia