Gamma-Ray Burst Phenomenon as Collapse of QED Magnetized Vacuum Bubble: Analogy with Sonoluminescence

We consider the phenomenon of a gamma-ray burst as a nonlinear collapse of a magnetic cavity surrounding a neutron star with very strong magnetic field B = 10^15 - 10^16 G due to the process of the bubble shape instability in a resonant MHD field of the accreting plasma. The QED effect of vacuum polarizability by the strong magnetic field is taken into account. We develop an analogy with the phenomenon of sonoluminescence (SL) when the gas bubble is located in the surrounding liquid with a driven sound intensity. We show that this analogy between GRB and SL phenomena really exists.Comment: 14 pages, submitted to Natur

Crystal structure, incommensurate magnetic order and ferroelectricity in mn1−x_{1-x}cux_{x}wo4{_4} (x=0-0.19)

We have carried out a systematic study on the effect of Cu doping on nuclear, magnetic, and dielectric properties in Mn$_{1-x}$Cu$_{x}$WO$_4$ for ${0}\leq{x}\leq{0.19}$ by a synergic use of different techniques, viz, heat capacity, magnetization, dielectric, and neutron powder diffraction measurements. Via heat capacity and magnetization measurements we show that with increasing Cu concentration magnetic frustration decreases, which leads to the stabilization of commensurate magnetic ordering. This was further verified by temperature-dependent unit cell volume changes derived from neutron diffraction measurements which was modeled by the Gr\"{u}neisen approximation. Dielectric measurements show a low temperature phase transition below about 9-10 K. Further more, magnetic refinements reveal no changes below this transition indicating a possible spin-flop transition which is unique to the Cu doped system. From these combined studies we have constructed a magnetoelectric phase diagram of this compound.Comment: 9 pages, 9 figures, accepted for publication in PR

Testing the Noncommutative Standard Model at a Future Photon Collider

Extensions of the Standard Model of elementary particle physics to noncommutative geometries have been proposed as a low energy limit of string models. Independent of this motivation, one may consider such a model as an effective field theory with higher-dimensional operators containing an antisymmetric rank-two background field. We study the signals of such a Noncommutative Standard Model (NCSM) and analyze the discovery potential of a future photon collider, considering angular distributions in fermion pair production.Comment: 13 pages RevTeX, Feynman diagrams and figures included, references added, typographical errors in Feynman rules corrected (all results remain unchangend, since correct Feynman rules were used in the calculations), to appear in Phys. Rev.

Muscle recovery after ACL reconstruction with 4-strand semitendinosus graft harvested through either a posterior or anterior incision: A preliminary study

AbstractIntroductionHarvesting of a 4-strand semitendinosis (ST4) graft during anterior cruciate ligament (ACL) reconstruction can be performed through either a posterior or anterior approach. The objective of this study was to evaluate the recovery of the quadriceps and hamstring muscles as a function of the graft harvesting method. We hypothesized that posterior harvesting (PH) would lead to better recovery in hamstring strength than anterior harvesting (AH).MethodsIn this prospective study, the semitendinosus was harvested through an anterior incision in the first group of patients and through a posterior one in the second group of patients. The patients were enrolled consecutively, without randomization. Isokinetic muscle testing was performed three and six months postoperative to determine the strength deficit in the quadriceps and hamstring muscles of the operated leg relative to the uninjured contralateral leg.ResultsThirty-nine patients were included: 20 in the AH group and 19 in the PH group. The mean quadriceps strength deficit after three and six months was 42% and 26% for AH and 29% and 19% for the PH, respectively (P=0.01 after three months and P=0.16 after six months). The mean hamstring strength deficit after three and six months was 31% and 17% for AH and 23% and 15% for the PH, respectively (P=0.09 after three months and P=0.45 after six months). After three months, the PH group had recovered 12% more quadriceps muscle strength than the AH group (P=0.03).ConclusionOur hypothesis was not confirmed. Harvesting of a ST4 graft for ACL reconstruction using a posterior approach led to better muscle strength recovery in the quadriceps only after three months.Case control studyLevel 3

Spacetime Noncommutativity in Models with Warped Extradimensions

We construct consistent noncommutative (NC) deformations of the Randall-Sundrum spacetime that solve the NC Einstein equations with a non-trivial Poisson tensor depending on the fifth coordinate. In a class of these deformations where the Poisson tensor is exponentially localized on one of the branes (the NC-brane), we study the effects on bulk particles in terms of Lorentz-violating operators induced by NC-brane interactions. We sketch two models in which massive bulk particles mediate NC effects to an almost-commutative SM-brane, such that observables at high energy colliders are enhanced with respect to low energy and astrophysical observables.Comment: 15 pages, LaTeX, pdf figures included, to appear in JHE

Algebraic approach to quantum field theory on a class of noncommutative curved spacetimes

In this article we study the quantization of a free real scalar field on a class of noncommutative manifolds, obtained via formal deformation quantization using triangular Drinfel'd twists. We construct deformed quadratic action functionals and compute the corresponding equation of motion operators. The Green's operators and the fundamental solution of the deformed equation of motion are obtained in terms of formal power series. It is shown that, using the deformed fundamental solution, we can define deformed *-algebras of field observables, which in general depend on the spacetime deformation parameter. This dependence is absent in the special case of Killing deformations, which include in particular the Moyal-Weyl deformation of the Minkowski spacetime.Comment: LaTeX 14 pages, no figures, svjour3.cls style; v2: clarifications and references added, compatible with published versio

Current prevalence of self-reported interpersonal violence among adult patients seen at a university hospital emergency department in Switzerland.

To evaluate the current prevalence of self-reported interpersonal violence amongst patients consulting at the emergency department (ED) of a university hospital and to describe the characteristics of the violence sustained. Ours was a cross-sectional study using a modified version of the Partner Violence Screen questionnaire, which was distributed to every patient over 16 years old consulting at the ED between the 1st and 30th September 2016. Excluded were those incapable of decision-making, unable to understand owing to language difficulties, or in police detention. Questions pertained to violence endured during the year prior to their attendance at the ED and, where relevant, the date, place, and type of violence (physical or psychological), the perpetrator and the means used (firearms or other weapons). Demographic details were taken from the hospital records. Of 628 patients included (participation rate 86%), 19% were victims of violence, for 27% of whom it was the motive for ED attendance. The median age of these victims of violence was 28 years (interquartile range 22–43), 39% were female, 71% single and 38% foreign nationals. Typical characteristics of self-reported violence were: (1) violence sustained within the previous 24 h (26%); (2) perpetrators unknown (35%); (3) occurrence at a café, bar, restaurant or nightclub (32%); (4) use of knives (19%); (5) prior consumption of alcohol by the victims themselves (28%). Females were more susceptible to domestic violence than males (45 vs 7%), the latter mostly reporting public violence (64 vs 43% in women). The prevalence of self-reported interpersonal violence has reached one patient in five in our ED. Our results underline the importance of screening for this, as well as providing the means to offer specific follow-up. &nbsp

Antibiotic stewardship implementation and patient-level antibiotic use at hospitals with and without on-site Infectious Disease specialists.

Many US hospitals lack Infectious Disease (ID) specialists, which may hinder antibiotic stewardship efforts. We sought to compare patient-level antibiotic exposure at Veterans Health Administration (VHA) hospitals with and without an on-site ID specialist, defined as an ID physician and/or ID pharmacist. This retrospective VHA cohort included all acute-care patient-admissions during 2016. A mandatory survey was used to identify hospitals' antibiotic stewardship processes and their access to an on-site ID specialist. Antibiotic use was quantified as days of therapy (DOT) per days-present and categorized based on National Healthcare Safety Network definitions. A negative binomial regression model with risk adjustment was used to determine the association between presence of an on-site ID specialist and antibiotic use at the level of patient-admissions. Eighteen of 122 (14.8%) hospitals lacked an on-site ID specialist; there were 525,451 (95.8%) admissions at ID hospitals and 23,007 (4.2%) at non-ID sites. In the adjusted analysis, presence of an ID specialist was associated with lower total inpatient antibacterial use [OR 0.92, (95% CI, 0.85-0.99)]. Presence of an ID specialist was also associated with lower use of broad-spectrum antibacterials [OR 0.61 (95% CI, 0.54-0.70)] and higher narrow-spectrum beta-lactam use [OR 1.43 (95% CI, 1.22-1.67)]. Total antibacterial exposure (inpatient plus post-discharge) was lower among patients at ID versus non-ID sites [OR 0.92 (95% CI, 0.86-0.99)]. Patients at hospitals with an ID specialist received antibiotics in a way more consistent with stewardship principles. The presence of an ID specialist may be important to effective antibiotic stewardship

Excess wing in glass-forming glycerol and LiCl-glycerol mixtures detected by neutron scattering

The relaxational dynamics in glass-forming glycerol and glycerol mixed with LiCl is in-vestigated using different neutron scattering techniques. The performed neutron spin-echo experiments, which extend up to relatively long relaxation-time scales of the order of 10 ns, should allow for the detection of contributions from the so-called excess wing. This phenomenon, whose microscopic origin is controversially discussed, arises in a variety of glass formers and, until now, was almost exclusively investigated by dielectric spectros-copy and light scattering. Here we show that the relaxational process causing the excess wing also can be detected by neutron scattering, which directly couples to density fluctua-tions.Comment: 8 pages, 6 figure

Antibiotic Stewardship Implementation and Antibiotic Use at Hospitals With and Without On-site Infectious Disease Specialists.

BackgroundMany US hospitals lack infectious disease (ID) specialists, which may hinder antibiotic stewardship efforts. We sought to compare patient-level antibiotic exposure at Veterans Health Administration (VHA) hospitals with and without an on-site ID specialist, defined as an ID physician and/or ID pharmacist.MethodsThis retrospective VHA cohort included all acute-care patient admissions during 2016. A mandatory survey was used to identify hospitals' antibiotic stewardship processes and their access to an on-site ID specialist. Antibiotic use was quantified as days of therapy per days present and categorized based on National Healthcare Safety Network definitions. A negative binomial regression model with risk adjustment was used to determine the association between presence of an on-site ID specialist and antibiotic use at the level of patient admissions.ResultsEighteen of 122 (14.8%) hospitals lacked an on-site ID specialist; there were 525 451 (95.8%) admissions at ID hospitals and 23 007 (4.2%) at non-ID sites. In the adjusted analysis, presence of an ID specialist was associated with lower total inpatient antibacterial use (odds ratio, 0.92; 95% confidence interval, .85-.99). Presence of an ID specialist was also associated with lower use of broad-spectrum antibacterials (0.61; .54-.70) and higher narrow-spectrum β-lactam use (1.43; 1.22-1.67). Total antibacterial exposure (inpatient plus postdischarge) was lower among patients at ID versus non-ID sites (0.92; .86-.99).ConclusionsPatients at hospitals with an ID specialist received antibiotics in a way more consistent with stewardship principles. The presence of an ID specialist may be important to effective antibiotic stewardship