Global and Local D-vortices

Codimension-two objects on a system of brane-antibrane are studied in the context of Born-Infeld type effective field theory with a complex tachyon and U(1)$\times$U(1) gauge fields. When the radial electric field is turned on in D2${\bar {\rm D}}$2, we find static regular global and local D-vortex solutions which could be candidates of straight cosmic D-strings in a superstring theory. A natural extension to DF-strings is briefly discussed.Comment: 24 pages, 10 eps figure

Nonequilibrium Evolution of Correlation Functions: A Canonical Approach

We study nonequilibrium evolution in a self-interacting quantum field theory invariant under space translation only by using a canonical approach based on the recently developed Liouville-von Neumann formalism. The method is first used to obtain the correlation functions both in and beyond the Hartree approximation, for the quantum mechanical analog of the $\phi^{4}$ model. The technique involves representing the Hamiltonian in a Fock basis of annihilation and creation operators. By separating it into a solvable Gaussian part involving quadratic terms and a perturbation of quartic terms, it is possible to find the improved vacuum state to any desired order. The correlation functions for the field theory are then investigated in the Hartree approximation and those beyond the Hartree approximation are obtained by finding the improved vacuum state corrected up to ${\cal O}(\lambda^2)$. These correlation functions take into account next-to-leading and next-to-next-to-leading order effects in the coupling constant. We also use the Heisenberg formalism to obtain the time evolution equations for the equal-time, connected correlation functions beyond the leading order. These equations are derived by including the connected 4-point functions in the hierarchy. The resulting coupled set of equations form a part of infinite hierarchy of coupled equations relating the various connected n-point functions. The connection with other approaches based on the path integral formalism is established and the physical implications of the set of equations are discussed with particular emphasis on thermalization.Comment: Revtex, 32 pages; substantial new material dealing with non-equilibrium evolution beyond Hartree approx. based on the LvN formalism, has been adde

Multiple Transitions to Chaos in a Damped Parametrically Forced Pendulum

We study bifurcations associated with stability of the lowest stationary point (SP) of a damped parametrically forced pendulum by varying $\omega_0$ (the natural frequency of the pendulum) and $A$ (the amplitude of the external driving force). As $A$ is increased, the SP will restabilize after its instability, destabilize again, and so {\it ad infinitum} for any given $\omega_0$. Its destabilizations (restabilizations) occur via alternating supercritical (subcritical) period-doubling bifurcations (PDB's) and pitchfork bifurcations, except the first destabilization at which a supercritical or subcritical bifurcation takes place depending on the value of $\omega_0$. For each case of the supercritical destabilizations, an infinite sequence of PDB's follows and leads to chaos. Consequently, an infinite series of period-doubling transitions to chaos appears with increasing $A$. The critical behaviors at the transition points are also discussed.Comment: 20 pages + 7 figures (available upon request), RevTex 3.

Differential effects of red meat/refined grain diet and dairy/chicken/nuts/whole grain diet on glucose, insulin and triglyceride in a randomized crossover study

Published: 30 October 2016Epidemiological studies suggest that a diet high in processed meat, with a high glycemic index is associated with an increased risk of type 2 diabetes. It is not clear if this is due to altered insulin sensitivity or an enhanced postprandial glucose. We aimed to compare the acute metabolic response of two different types of meals after ingestion of the matching diet for four weeks. The study was a randomized, crossover acute meal study. Volunteers consumed either a red meat/refined grain meal or a dairy/chicken/nuts/wholegrain meal after four weeks of the matching diet. After a three-week washout period and four weeks of the alternate diet, they consumed the matching meal. The diets differed with respect to both protein and carbohydrate sources. Blood samples were taken for 180 min for the measurement of glucose, insulin, C-peptide and triglyceride. Fifty-one participants (age: 35.1 ± 15.6 years; body mass index: 27.7 ± 6.9 kg/m², 17 with normal and 34 with impaired glucose tolerance) completed two meal tests. The area under the curve (p < 0.001) and incremental area under the curve (p = 0.001) for insulin was significantly higher after the red meat/refined grain diet than after the dairy/chicken/nuts/whole grain diet. There was an interaction between meal and glucose tolerance group (p < 0.05) in the area under the curve (AUC) and the incremental area under the curve (iAUC) of glucose; the red meat/refined grain diet increased glucose relative to the dairy/chicken/nuts/whole grain diet only in the normal group (+2.5 mmol/L/3 h). The red meat/refined grain diet increased glucose and insulin responses compared with the dairy/chicken/nuts/whole grain diet. This meal pattern would increase pancreatic stress long term and may account for the increased risk of type 2 diabetes with this diet.Yoona Kim, Jennifer B. Keogh and Peter M. Clifto

Perturbative Expansion around the Gaussian Effective Action: The Background Field Method

We develop a systematic method of the perturbative expansion around the Gaussian effective action based on the background field method. We show, by applying the method to the quantum mechanical anharmonic oscillator problem, that even the first non-trivial correction terms greatly improve the Gaussian approximation.Comment: 16 pages, 3 eps figures, uses RevTeX and epsf. Errors in Table 1 are corrected and new references are adde

The Complexity of Repairing, Adjusting, and Aggregating of Extensions in Abstract Argumentation

We study the computational complexity of problems that arise in abstract argumentation in the context of dynamic argumentation, minimal change, and aggregation. In particular, we consider the following problems where always an argumentation framework F and a small positive integer k are given. - The Repair problem asks whether a given set of arguments can be modified into an extension by at most k elementary changes (i.e., the extension is of distance k from the given set). - The Adjust problem asks whether a given extension can be modified by at most k elementary changes into an extension that contains a specified argument. - The Center problem asks whether, given two extensions of distance k, whether there is a "center" extension that is a distance at most (k-1) from both given extensions. We study these problems in the framework of parameterized complexity, and take the distance k as the parameter. Our results covers several different semantics, including admissible, complete, preferred, semi-stable and stable semantics

Cyanide-modified Pt(111) : structure, stability and hydrogen adsorption

A.C. acknowledges the support of the DGI (Spanish Ministry of Science and Innovation) through Project CTQ2009-07017. W.S. acknowledges financial support by the Deutsche Forschungsgemeinschaft under Schm 344/40-1, Schm 344/34-1.2 and FOR 1376. W.S. and P.Q. thank DFG-CONICET International Cooperation and CONICET for continued support. E.P.M.L. and M.Z.-M. wish to acknowledge CONICET PIP: 112-200801-000983, Secyt UNC, Program BID (PICT 2006N 946), and PME: 2006-01581 for financial support. P.Q. acknowledges PICT 0737-2008. A generous grant of computing time from the Baden-Wuerttemberg grid is gratefully acknowledged. M.E.-E. acknowledges an FPI fellowship from the Spanish Ministry of Science and Innovation and an accommodation grant at the Residencia de Estudiantes from the Madrid City Council.Peer reviewedPostprin

The effects of a stigma awareness intervention on finding and retaining paid employment a cluster randomized controlled trial among unemployed people with mental illness

Introduction: Stigma is one of the barriers to paid employment for people with mental illness. Deliberate (non-)disclosure decisions may prevent this, but the effects of stigma awareness interventions are mostly unknown. This study aims to examine the effectiveness of a stigma awareness intervention for employment specialists and a decision aid and two infographics about disclosure of mental illness on finding and retaining employment for unemployed people with mental illness, compared to usual guidance. Material and methods: A clustered RCT was conducted. Participants were unemployed people with mental illness who receive social benefits (N=153) and were recruited at eight locations. The control group received guidance as usual and the experimental group received guidance as usual combined with the stigma awareness intervention. Health, wellbeing, job seeking activities and disclosure were measured at baseline and 3, 6 and 12 months. Multilevel analyses were conducted to analyze the effects of the intervention on finding and retaining employment, controlled for other factors. Results: In the experimental group, after six (T2) and twelve months (T3) almost twice as many participants had found paid employment (T2: CG=26.1% vs EG=50.7%, p=0.003; T3: CG=34.4% vs EG=53.8%, p=0.026), and retained paid employment after twelve months (CG=23.4% vs EG=49.2%, p=0.002), compared to the control group. Conclusions: A stigma awareness intervention contributes to more often finding and retaining paid employment for people with mental illness

Superconducting proximity effect in the presence of strong spin scattering

We report measurements of the four terminal temperature dependent resistance of narrow Au wires implanted with ~100 ppm Fe impurities in proximity to superconducting Al films. The wires show an initial decrease in resistance as the temperature is lowered through the superconducting transition of the Al films, but then show an increase in resistance as the temperature is lowered further. In contrast to the case of pure Au wires in contact with a superconducting film, the resistance at the lowest temperatures rises above the normal state resistance. Analysis of the data shows that, in addition to contributions from magnetic scattering and electron-electron interactions, the temperature dependent resistivity shows a substantial contribution from the superconducting proximity effect, which exists even in the presence of strong spin scattering.Comment: 4 pages, 3 figure

Moments of the Virtual Photon Structure Function

The photon structure function is a useful testing ground for QCD. It is perturbatively computable apart from a contribution from what is usually called the hadronic component of the photon. There have been many proposals for this nonperturbative part of the real photon structure function. By studying moments of the virtual photon structure function, we explore the extent to which these proposed nonperturbative contributions can be identified experimentally.Comment: LaTeX, 16 pages + 14 compressed and uuencoded postscript figures, UMN-TH-1111/9