g_{rho sigma gamma} coupling constant in light cone QCD

The coupling constant g_{rho sigma gamma} is determined from light cone QCD sum rules. A comparison of our result with the ones existing in literature is presented.Comment: 7 pp, 2 figures (postscript formatted), LaTex formatte

Outcome Expectations of Total Knee Arthroplasty Patients: The Influence of Demographic Factors, Pain, Personality Traits, Physical and Psychological Status

Unfulfilled preoperative expectations have a strong influence on the outcome after total knee arthroplasty (TKA). More insight into determinants of the level of expectations is useful in identifying patients at risk for having expectations of the treatment result that are too high or too low. This information can be used in optimizing preoperative expectation management. The aim of the current study was to analyze to what extent preoperative outcome expectations of TKA patients are affected by psychological factors, demographic factors, pain, physical function, and general health status. We performed a cross-sectional analysis of 204 patients with symptomatic and radiographic knee osteoarthritis (OA), scheduled for primary TKA. Outcome expectations were measured using the hospital for special surgery knee replacement expectations survey. Independent variables included were age, sex, body mass index, and patient-reported outcome measures for pain, physical function, quality of life, anxiety, depression, catastrophizing, optimism, and pessimism. Multiple linear regression analyses were used to evaluate associations between these variables and preoperative outcome expectations. Female sex, higher age, higher depression score, and duration of complaints > 50 months showed to be significant predictors of lower expectations for the treatment outcome after TKA. Baseline pain and function scores were not related to the level of preoperative expectations. The present study aids in identifying patients at risk for having either too high or too low expectations. This knowledge can be utilized in individualized expectation management interventions

Conceptualizing autonomy in the context of chronic physical illness: relating philosophical theories to social scientific perspectives

The aim of this article is to conceptualize autonomy in the context of chronic physical illness. To this end, we compare and contrast a selection of contemporary philosophical theories of autonomy with social scientific perspectives on chronic illness, particularly models of disability and symbolic interactionism. The philosophical theories mainly depart from a positive conceptualization of autonomy, which involves actively shaping one's life and identifying with fundamental values. This conceptualization is preferred over a negative conceptualization, which defines autonomy as non-interference, for its compatibility with social models of disability and with the assumption that people are interdependent. Interference may disable, but also enable people with a chronic illness to shape their lives. What matters is that people can realize what they want to realize. We suggest that, in the context of chronic physical illness, autonomy might be conceptualized as correspondence between what people want their lives to be like and what their lives are actually like. Disturbed autonomy might be restored either by expanding opportunities to arrange life or by adjusting how one wants life to be arranged. The grounds for the latter approach might be questioned, first, if people have not adjusted what they want carefully, and second, if reorganization of the material and social environment would have made it unnecessary to adjust one's arrangement of life

Universal trapping scaling on the unstable manifold for a collisionless electrostatic mode

An amplitude equation for an unstable mode in a collisionless plasma is derived from the dynamics on the two-dimensional unstable manifold of the equilibrium. The mode amplitude $\rho(t)$ decouples from the phase due to the spatial homogeneity of the equilibrium, and the resulting one-dimensional dynamics is analyzed using an expansion in $\rho$. As the linear growth rate $\gamma$ vanishes, the expansion coefficients diverge; a rescaling $\rho(t)\equiv\gamma^2\,r(\gamma t)$ of the mode amplitude absorbs these singularities and reveals that the mode electric field exhibits trapping scaling $|E_1|\sim\gamma^2$ as $\gamma\rightarrow0$. The dynamics for $r(\tau)$ depends only on the phase $e^{i\xi}$ where $d\epsilon_{{k}} /dz=|{\epsilon_{{k}}}|e^{-i\xi/2}$ is the derivative of the dielectric as $\gamma\rightarrow0$.Comment: 11 pages (Latex/RevTex), 2 figures available in hard copy from the Author ([email protected]); paper accepted by Physical Review Letter

The Hubble Effective Potential

We generalize the effective potential to scalar field configurations which are proportional to the Hubble parameter of a homogeneous and isotropic background geometry. This may be useful in situations for which curvature effects are significant. We evaluate the one loop contribution to the Hubble Effective Potential for a massless scalar with arbitrary conformal and quartic couplings, on a background for which the deceleration parameter is constant. Among other things, we find that inflationary particle production leads to symmetry restoration at late times.Comment: 32 pages, 6 figures, version 2 published in JCAP with some typoes corrected and two additional reference

The graviton one-loop effective action in cosmological space-times with constant deceleration

We consider the quantum Friedmann equations which include one-loop vacuum fluctuations due to gravitons and scalar field matter in a FLRW background with constant $\epsilon=-{\dot{H}}/{H^2}$. After several field redefinitions, to remove the mixing between the gravitational and matter degrees of freedom, we can construct the one loop correction to the Friedmann equations. Due to cosmological particle creation, the propagators needed in such a calculation are typically infrared divergent. In this paper we construct the graviton and matter propagators, making use of the recent construction of the infrared finite scalar propagators calculated on a compact spatial manifold in \cite{Janssen:2008px}. The resulting correction to the Friedman equations is suppressed with respect to the tree level contribution by a factor of $H^2/m_p^2$ and shows no secular growth.Comment: 37 pages, 1 figure. Revised version, including a proper treatment of the infrared secto

Recruitment failure and futility were the most common reasons for discontinuation of clinical drug trials. Results of a nationwide inception cohort study in the Netherlands

Objectives The objective of the study was to identify the reasons for discontinuation of clinical drug trials and to evaluate whether efficacy-related discontinuations were adequately planned in the trial protocol. Study Design and Setting All clinical drug trials in the Netherlands, reviewed by institutional review boards in 2007, were followed until December 2015. Data were obtained through the database of the Dutch competent authority (Central Committee on Research Involving Human Subjects [CCMO]) and a questionnaire to the principal investigators. Reasons for trial discontinuation were the primary outcome of the study. Three reasons for discontinuation were analyzed separately: all cause, recruitment failure, and efficacy related (when an interim analysis had demonstrated futility or superiority). Among the efficacy-related discontinuations, we examined whether the data monitoring committee, the stopping rule, and the moment of the interim analysis in the trial progress were specified in the trial protocol. Results Of the 574 trials, 102 (17.8%) were discontinued. The most common reasons were recruitment failure (33 of 574; 5.7%) and solely efficacy related (30 of 574; 5.2%). Of the efficacy-related discontinuations, 10 of 30 (33.3%) of the trial protocols reported all three aspects in the trial protocol, and 20 of 30 (66.7%) reported at least one aspect in the trial protocol. Conclusion One out of five clinical drug trials is discontinued before the planned trial end, with recruitment failure and futility as the most common reasons. The target sample size of trials should be feasible, and interim analyses should be adequately described in trial protocols

Mechanistic insights into the C₅₅-P targeting lipopeptide antibiotics revealed by structure-activity studies and high-resolution crystal structures

AbstractThe continued rise of antibiotic resistance is a global concern that threatens to undermine many aspects of modern medical practice. Key to addressing this threat is the discovery and development of new antibiotics that operate by unexploited modes of action. The so-called calcium-dependent lipopeptide antibiotics (CDAs) are an important emerging class of natural products that provides a source of new antibiotic agents rich in structural and mechanistic diversity. Notable in this regard is the subset of CDAs comprising the laspartomycins and amphomycins/friulimicins that specifically target the bacterial cell wall precursor undecaprenyl phosphate (C55-P). In this study we describe the design and synthesis of new C55-P-targeting CDAs with structural features drawn from both the laspartomycin and amphomycin/friulimicin classes. Assessment of these lipopeptides revealed previously unknown and surprisingly subtle structural features that are required for antibacterial activity. High-resolution crystal structures further indicate that the amphomycin/friulimicin-like lipopeptides adopt a unique crystal packing that governs their interaction with C55-P and provides an explanation for their antibacterial effect. In addition, live-cell microscopy studies provide further insights into the biological activity of the C55-P targeting CDAs highlighting their unique mechanism of action relative to the clinically used CDA daptomycin.Microbial Biotechnolog

On the role of the magnetic dipolar interaction in cold and ultracold collisions: Numerical and analytical results for NH(3Σ−^3\Sigma^-) + NH(3Σ−^3\Sigma^-)

We present a detailed analysis of the role of the magnetic dipole-dipole interaction in cold and ultracold collisions. We focus on collisions between magnetically trapped NH molecules, but the theory is general for any two paramagnetic species for which the electronic spin and its space-fixed projection are (approximately) good quantum numbers. It is shown that dipolar spin relaxation is directly associated with magnetic-dipole induced avoided crossings that occur between different adiabatic potential curves. For a given collision energy and magnetic field strength, the cross-section contributions from different scattering channels depend strongly on whether or not the corresponding avoided crossings are energetically accessible. We find that the crossings become lower in energy as the magnetic field decreases, so that higher partial-wave scattering becomes increasingly important \textit{below} a certain magnetic field strength. In addition, we derive analytical cross-section expressions for dipolar spin relaxation based on the Born approximation and distorted-wave Born approximation. The validity regions of these analytical expressions are determined by comparison with the NH + NH cross sections obtained from full coupled-channel calculations. We find that the Born approximation is accurate over a wide range of energies and field strengths, but breaks down at high energies and high magnetic fields. The analytical distorted-wave Born approximation gives more accurate results in the case of s-wave scattering, but shows some significant discrepancies for the higher partial-wave channels. We thus conclude that the Born approximation gives generally more meaningful results than the distorted-wave Born approximation at the collision energies and fields considered in this work.Comment: Accepted by Eur. Phys. J. D for publication in Special Issue on Cold Quantum Matter - Achievements and Prospects (2011

Scalar cosmological perturbations from inflationary black holes

We study the correction to the scale invariant power spectrum of a scalar field on de Sitter space from small black holes that formed during a pre-inflationary matter dominated era. The formation probability of such black holes is estimated from primordial Gaussian density fluctuations. We determine the correction to the spectrum by first deriving the Keldysh propagator for a massless scalar field on Schwarzschild-de Sitter space. Our results suggest that the effect is strong enough to be tested -- and possibly even ruled out -- by observations.Comment: 41 pages, 11 figures, published versio