Deuteron Magnetic Quadrupole Moment From Chiral Effective Field Theory

We calculate the magnetic quadrupole moment (MQM) of the deuteron at leading order in the systematic expansion provided by chiral effective field theory. We take into account parity and time-reversal violation which, at the quark-gluon level, results from the QCD vacuum angle and dimension-six operators that originate from physics beyond the Standard Model. We show that the deuteron MQM can be expressed in terms of five low-energy constants that appear in the parity- and time-reversal-violating nuclear potential and electromagnetic current, four of which also contribute to the electric dipole moments of light nuclei. We conclude that the deuteron MQM has an enhanced sensitivity to the QCD vacuum angle and that its measurement would be complementary to the proposed measurements of light-nuclear EDMs

Fusarium species and mycotoxin profiles on commercial maize hybrids in Germany

Abstract High year-to-year variability in the incidence of Fusarium spp. and mycotoxin contamination was observed in a two-year survey investigating the impact of maize ear rot in 84 field samples from Germany. Fusarium verticillioides, F. graminearum, and F. proliferatum were the predominant species infecting maize kernels in 2006, whereas in 2007 the most frequently isolated species were F. graminearum, F. cerealis and F. subglutinans. Fourteen Fusariumrelated mycotoxins were detected as contaminants of maize kernels analyzed by a multi-mycotoxin determination method. In 2006, a growth season characterized by high temperature and low rainfall during anthesis and early grain filling, 75% of the maize samples were contaminated with deoxynivalenol, 34% with fumonisins and 27% with zearalenone. In 2007, characterized by moderate temperatures and frequent rainfall during the entire growth season, none of the 40 maize samples had quantifiable levels of fumonisins while deoxynivalenol and zearalenone were detected in 90% and 93% of the fields, respectively. In addition, 3-acetyldeoxynivalenol, 15-acetyldeoxnivalenol, moniliformin, beauvericin, nivalenol and enniatin B were detected as common contaminants produced in both growing seasons. The results demonstrate a significant mycotoxin contamination associated with maize ear rots in Germany and indicate, with regard to anticipated climate change, that fumonisins-producing species already present in German maize production may become more important. Keywords Deoxynivalenol . Ear rot . F. verticillioides . F. graminearum . Fumonisin . Zearalenon

The Dynamical Cluster Approximation: Non-Local Dynamics of Correlated Electron Systems

We recently introduced the dynamical cluster approximation(DCA), a new technique that includes short-ranged dynamical correlations in addition to the local dynamics of the dynamical mean field approximation while preserving causality. The technique is based on an iterative self-consistency scheme on a finite size periodic cluster. The dynamical mean field approximation (exact result) is obtained by taking the cluster to a single site (the thermodynamic limit). Here, we provide details of our method, explicitly show that it is causal, systematic, $\Phi$-derivable, and that it becomes conserving as the cluster size increases. We demonstrate the DCA by applying it to a Quantum Monte Carlo and Exact Enumeration study of the two-dimensional Falicov-Kimball model. The resulting spectral functions preserve causality, and the spectra and the CDW transition temperature converge quickly and systematically to the thermodynamic limit as the cluster size increases.Comment: 19 pages, 13 postscript figures, revte

Electric Dipole Moments of Light Nuclei From Chiral Effective Field Theory

We set up the framework for the calculation of electric dipole moments (EDMs) of light nuclei using the systematic expansion provided by chiral effective field theory (EFT). We take into account parity (P) and time-reversal (T) violation which, at the quark-gluon level, originates from the QCD vacuum angle and dimension-six operators capturing physics beyond the Standard Model. We argue that EDMs of light nuclei can be expressed in terms of six low-energy constants that appear in the P- and T-violating nuclear potential and electric current. As examples, we calculate the EDMs of the deuteron, the triton, and 3He in leading order in the EFT expansion

Self-report Versus Measured Physical Activity Levels During Outpatient Cardiac Rehabilitation

Purpose: Many patients with coronary artery disease (CAD) do not achieve the recommended physical activity (PA) levels during and after cardiac rehabilitation (CR). The aim of this study was to analyze moderate to vigorous physical activity (MVPA) levels and the differences between perceived (self-reported) and measured (activity monitor) MVPA in CAD patients during CR. The second aim was to analyze which patient characteristics were associated with this difference. Methods: A two-center observational-sectional study was conducted within the Department of Rehabilitation Medicine of the University Medical Center Groningen between January and April 2018. Adults with CAD, following an outpatient CR program, were included. Perceived MVPA was assessed with the Short Questionnaire to Assess Health-enhancing Physical Activity and compared with ActivPAL3 activity monitor outcomes over a period of 7 d. Results: Fifty-one patients with CAD (age 59.4 ± 7.1 yr, eight females) were recruited. Four patients (8%) did not achieve the recommended guideline level of ≥150 min/wk of MVPA. Patients spent ≥80% of the week in sedentary activities. Patients overestimated MVPA with a median of 805 (218, 1363) min/wk (P < .001). The selected patient characteristics (age, body mass index, type of CAD, type of CR, social support, and self-efficacy) were not associated with this overestimation. Conclusions: Most patients with CAD, participating in an outpatient CR program, do achieve MVPA exercise recommendations but spend simultaneously too much time in sedentary activities

Parity- and Time-Reversal-Violating Form Factors of the Deuteron

We calculate the electric-dipole and magnetic-quadrupole form factors of the deuteron that arise as a low-energy manifestation of parity and time-reversal violation in quark-gluon interactions of effective dimension four and six: the QCD vacuum angle, the quark electric and chromo-electric dipole moments, and the gluon chromo-electric dipole moment. Within the framework of two-flavor chiral perturbation theory, we show that the relative sizes of the corresponding moments allow an identification of the symmetry-breaking source

First principles studies of modulated Co/Cu superlattices with strongly and weakly exchange biased Co-monolayers

First-principles calculations have been performed in order to determine effective exchange integrals between {\it strongly} and {\it weakly} exchange-coupled Co monolayers in certain modulated periodic $CoCu_2/CoCu_n$-type superlattices with three non-equivalent Co planes, which have not yet been studied hitherto. For $3\le n\le 6$ we find that the two non-equivalent exchange integrals have opposite signs, i.e.~the strong coupling is antiferromagnetic and the weak coupling ferromagnetic, and differ for $n\ne 4$ from each other by one order of magnitude. It is shown that the results depend on the system as a whole and could not be obtained from separate parts. Finally we suggest that ''spin valve'' systems of such kind should be considered when trying to obtain good magneto-resistance together with low switching-fields.Comment: LaTex, 9 pages, including two .eps-figure

Insulator-to-metal crossover induced by local spin fluctuations in strongly correlated systems

We study the simplified Hubbard (SH) model in the presence of a transverse field in the infinite dimension limit. The relevant one-particle Green's functions of the model are obtained by means a perturbative treatment of the hopping and of the transverse field around the atomic limit. We consider an analytical solution for the impurity problem. It is shown that this solution is very accurate in describing the spectral properties of the heavy-particles of the SH for intermediate and strong values of the on-site Coulomb interaction $U$. We find that for large values of $U$ an insulator-metal transition takes place as a function of the transverse field. We analyze the metallic phase through the behavior of the density of states and of the optical conductivity and static resistivity. Our results for the latter quantity agree with what is observed in experiments on $Bi_2Sr_2CuO_y$.Comment: 6 pages, 5 figures, to appear in Journal of Physics: Condensed Matte