The Large N_c Baryon-Meson I_t = J_t Rule Holds for Three Flavors

It has long been known that nonstrange baryon-meson scattering in the 1/N_c expansion of QCD greatly simplifies when expressed in terms of t-channel exchanges: The leading-order amplitudes satisfy the selection rule I_t = J_t. We show that I_t = J_t, as well as Y_t = 0, also hold for the leading amplitudes when the baryon and/or meson contain strange quarks, and also characterize their 1/N_c corrections, thus opening a new front in the phenomenological study of baryon-meson scattering and baryon resonances.Comment: 12 pages, 0 figures, ReVTe

Renormalized Kaluza-Klein theories

Using six-dimensional quantum electrodynamics ($QED_6$) as an example we study the one-loop renormalization of the theory both from the six and four-dimensional points of view. Our main conclusion is that the properly renormalized four dimensional theory never forgets its higher dimensional origin. In particular, the coefficients of the neccessary extra counterterms in the four dimensional theory are determined in a precise way. We check our results by studying the reduction of $QED_4$ on a two-torus.Comment: LaTeX, 36 pages. A new section added; references improved, typos fixe

Our virtual tribe:Sustaining and enhancing community via online music improvisation

This article documents experiences of Glasgow Improvisers Orchestra’s virtual, synchronous improvisation sessions during COVID-19 pandemic via interviews with 29 participants. Sessions included an international, gender balanced, and cross generational group of over 70 musicians all of whom were living under conditions of social distancing. All sessions were recorded using Zoom software. After 3 months of twice weekly improvisation sessions, 29 interviews with participants were undertaken, recorded, transcribed, and analyzed. Key themes include how the sessions provided opportunities for artistic development, enhanced mood, reduced feelings of isolation, and sustained and developed community. Particular attention is placed upon how improvisation as a universal, real time, social, and collaborative process facilitates interaction, allowing the technological affordances of software (latencies, sound quality, and gallery/speaker view) and hardware (laptop, tablet, instruments, microphones, headphones, and objects in room) to become emergent properties of artistic collaborations. The extent to which this process affects new perceptual and conceptual breakthroughs for practitioners is discussed as is the crucial and innovative relationship between audio and visual elements. Analysis of edited films of the sessions highlight artistic and theoretical and conceptual issues discussed. Emphasis is given to how the domestic environment merges with technologies to create The Theatre of Home.publishedVersio

Interacción calmodulina-melatonina: efectos sobre la oxidación de la calmodulina y la actividad de la calmodulina cinasa II

Reactive oxygen species are the most reactive molecules that, among other characteristics, have different half-lives, cellular concentrations, and reaction targets. They are present in different compartments and react with different gradients of molecules in the cell. In particular, proteins can react with almost all oxygen radicals present in the cell, and ultimately, these oxidation reactions produce conformational changes in these molecules due to carbonylation and sulfoxidation that impact different cellular functions. In the case of calmodulin, a protein that acts as a Ca2+ sensor, it can be oxidized by oxygen free radicals and can undergo modifications in its secondary structure, and consequently, its function can be altered until it is degraded. Free radicals are regulated in the cell by antioxidant mechanisms which can be classified as enzymatic such as superoxide dismutase and non-enzymatic such as glutathione. Other molecules can capture free radicals and therefore participate in the regulation of oxidation, such as melatonin, which is a hormone with multiple functions in addition to acting as a signal that regulates the circadian rhythm. In psychiatric diseases, particularly schizophrenia, antioxidant mechanisms are deregulated and high levels of oxidation have been found in brain tissue, as well as the presence of metabolites that indirectly show an increase in free radicals. In this dissertation work, the calmodulin-melatonin interaction and its impact on enzyme activity in an oxidative microenvironment were studied, as well as the oxidation profile in cells of patients with schizophrenia.Las especies reactivas de oxígeno son las moléculas más reactivas que, entre otras características, tienen diferentes vidas medias, concentraciones celulares y blancos de reacción. Están presentes en diferentes compartimentos y reaccionan con diferentes gradientes de moléculas en la célula. En particular las proteínas pueden reaccionar con casi todos los radicales de oxígeno presentes en la célula y al final, estas reacciones de oxidación producen cambios conformacionales en estas moléculas debido a la carbonilación y a la sulfoxidación que impacta diferentes funciones celulares. En el caso de la calmodulina, una proteína que actúa como un sensor de Ca2+, se puede oxidar por radicales libres de oxígeno y puede experimentar modificaciones en su estructura secundaria y en consecuencia se puede alterar su función hasta llegar a su degradación. Los radicales libres son regulados en la célula por mecanismos antioxidantes los cuales se pueden clasificar en enzimáticos como la superóxido dismutasa y no enzimáticos como el glutatión. Existen otras moléculas que pueden captar radicales libres y por lo tanto participar en la regulación de la oxidación, como lo es la melatonina, que es una hormona de múltiples funciones además de actuar como una señal que sincroniza el medio interno con el fotoperiodo. En las enfermedades psiquiátricas, en particular en la esquizofrenia, están desregulados los mecanismos antioxidantes y se han encontrado altos niveles de oxidación en tejido cerebral, así como la presencia de metabolitos que de manera indirecta muestran el incremento de radicales libres. En esta tesis se estudió la interacción calmodulina melatonina y su impacto en la actividad enzimática en un microambiente oxidante, así como también se caracterizó el perfil de oxidación en células de pacientes con esquizofrenia

Transmission electron microscopy and energy dispersive X-ray spectroscopy on the worn surface of nano-structured TiAlN/VN multilayer coating

Nano-structured TiAIN/VN multilayer hard coatings grown by cathodic arc metal ion etching and unbalanced magnetron sputtering deposition have repeatedly shown low coefficients of friction and wear. In this paper, we employed the combined methods of cross-sectional ion beam milling sample preparation, conventional transmission electron microscopy, energy dispersive X-ray spectroscopy and quantitative spectrum analysis to give a comprehensive characterization of wear induced tribofilm, worn TiAIN/VN surface as well as wear debris. The major wear mechanism operating in the TiAIN/VN coating is the tribo-oxidation wear. A 20-50 nm thick tribofilm was observed on the TiAIN/VN worn surface, having inhomogeneous density, amorphous structure and multicomponent V-Al-Ti-O composition. Therefore the real sliding contact during the ball-on-disk test was a three-body sliding system including the tribofilm, in which the self-sintering and shearing deformation of the multicomponent oxide film played a significant role in determining the low friction coefficient. Owing to the low friction and high hardness, the TiAIN/VN worn surface retained good structural integrity without any crack, delamination or detectable deformation, resulting in minimized mechanical wear. (c) 2005 Elsevier B.V. All rights reserved

Relationship between FEV1 change and patient-reported outcomes in randomised trials of inhaled bronchodilators for stable COPD: a systematic review.

BACKGROUND: Interactions between spirometry and patient-reported outcomes in COPD are not well understood. This systematic review and study-level analysis investigated the relationship between changes in FEV1 and changes in health status with bronchodilator therapy. METHODS: Six databases (to October 2009) were searched to identify studies with long-acting bronchodilator therapy reporting FEV1 and health status, dyspnoea or exacerbations. Mean and standard deviations of treatment effects were extracted for each arm of each study. Relationships between changes in trough FEV1 and outcomes were assessed using correlations and random-effects regression modelling. The primary outcome was St George's Respiratory Questionnaire (SGRQ) total score. RESULTS: Thirty-six studies (≥ 3 months) were included. Twenty-two studies (23,654 patients) with 49 treatment arms each contributing one data point provided SGRQ data. Change in trough FEV1 and change in SGRQ total score were negatively correlated (r = -0.46, p < 0.001); greater increases in FEV1 were associated with greater reductions (improvements) in SGRQ. The correlation strengthened with increasing study duration from 3 to 12 months. Regression modelling indicated that 100 mL increase in FEV1 (change at which patients are more likely to report improvement) was associated with a statistically significant reduction in SGRQ of 2.5 (95% CI 1.9, 3.1), while a clinically relevant SGRQ change (4.0) was associated with 160.6 (95% CI 129.0, 211.6) mL increase in FEV1. The association between change in FEV1 and other patient-reported outcomes was generally weak. CONCLUSIONS: Our analyses indicate, at a study level, that improvement in mean trough FEV1 is associated with proportional improvements in health status

Toward a structural understanding of turbulent drag reduction: nonlinear coherent states in viscoelastic shear flows

Nontrivial steady flows have recently been found that capture the main structures of the turbulent buffer layer. We study the effects of polymer addition on these "exact coherent states" (ECS) in plane Couette flow. Despite the simplicity of the ECS flows, these effects closely mirror those observed experimentally: Structures shift to larger length scales, wall-normal fluctuations are suppressed while streamwise ones are enhanced, and drag is reduced. The mechanism underlying these effects is elucidated. These results suggest that the ECS are closely related to buffer layer turbulence.Comment: 5 pages, 3 figures, published version, Phys. Rev. Lett. 89, 208301 (2002

Cost-effectiveness of strategies preventing late-onset infection in preterm infants

OBJECTIVE: Developing a model to analyse the cost-effectiveness of interventions preventing late-onset infection (LOI) in preterm infants and applying it to the evaluation of anti-microbial impregnated peripherally inserted central catheters (AM-PICCs) compared with standard PICCs (S-PICCs). DESIGN: Model-based cost-effectiveness analysis, using data from the Preventing infection using Antimicrobial Impregnated Long Lines (PREVAIL) randomised controlled trial linked to routine healthcare data, supplemented with published literature. The model assumes that LOI increases the risk of neurodevelopmental impairment (NDI). SETTING: Neonatal intensive care units in the UK National Health Service (NHS). PATIENTS: Infants born ≤32 weeks gestational age, requiring a 1 French gauge PICC. INTERVENTIONS: AM-PICC and S-PICC. MAIN OUTCOME MEASURES: Life expectancy, quality-adjusted life years (QALYs) and healthcare costs over the infants' expected lifetime. RESULTS: Severe NDI reduces life expectancy by 14.79 (95% CI 4.43 to 26.68; undiscounted) years, 10.63 (95% CI 7.74 to 14.02; discounted) QALYs and costs £19 057 (95% CI £14 197; £24697; discounted) to the NHS. If LOI causes NDI, the maximum acquisition price of an intervention reducing LOI risk by 5% is £120. AM-PICCs increase costs (£54.85 (95% CI £25.95 to £89.12)) but have negligible impact on health outcomes (-0.01 (95% CI -0.09 to 0.04) QALYs), compared with S-PICCs. The NHS can invest up to £2.4 million in research to confirm that AM-PICCs are not cost-effective. CONCLUSIONS: The model quantifies health losses and additional healthcare costs caused by NDI and LOI during neonatal care. Given these consequences, interventions preventing LOI, even by a small extent, can be cost-effective. AM-PICCs, being less effective and more costly than S-PICC, are not likely to be cost-effective. TRIAL REGISTRATION NUMBER: NCT03260517

A Comparative Computer Simulation of Dendritic Morphology

Computational modeling of neuronal morphology is a powerful tool for understanding developmental processes and structure-function relationships. We present a multifaceted approach based on stochastic sampling of morphological measures from digital reconstructions of real cells. We examined how dendritic elongation, branching, and taper are controlled by three morphometric determinants: Branch Order, Radius, and Path Distance from the soma. Virtual dendrites were simulated starting from 3,715 neuronal trees reconstructed in 16 different laboratories, including morphological classes as diverse as spinal motoneurons and dentate granule cells. Several emergent morphometrics were used to compare real and virtual trees. Relating model parameters to Branch Order best constrained the number of terminations for most morphological classes, except pyramidal cell apical trees, which were better described by a dependence on Path Distance. In contrast, bifurcation asymmetry was best constrained by Radius for apical, but Path Distance for basal trees. All determinants showed similar performance in capturing total surface area, while surface area asymmetry was best determined by Path Distance. Grouping by other characteristics, such as size, asymmetry, arborizations, or animal species, showed smaller differences than observed between apical and basal, pointing to the biological importance of this separation. Hybrid models using combinations of the determinants confirmed these trends and allowed a detailed characterization of morphological relations. The differential findings between morphological groups suggest different underlying developmental mechanisms. By comparing the effects of several morphometric determinants on the simulation of different neuronal classes, this approach sheds light on possible growth mechanism variations responsible for the observed neuronal diversity

Efficacy and safety of once-daily aclidinium in chronic obstructive pulmonary disease

BACKGROUND: The long-term efficacy and safety of aclidinium bromide, a novel, long-acting muscarinic antagonist, were investigated in patients with moderate to severe chronic obstructive pulmonary disease (COPD). METHODS: In two double-blind, 52-week studies, ACCLAIM/COPD I (n=843) and II (n=804), patients were randomised to inhaled aclidinium 200 μg or placebo once-daily. Patients were required to have a post-bronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity ratio of ≤70% and FEV1<80% of the predicted value. The primary endpoint was trough FEV1 at 12 and 28 weeks. Secondary endpoints were health status measured by St George's Respiratory Questionnaire (SGRQ) and time to first moderate or severe COPD exacerbation. RESULTS: At 12 and 28 weeks, aclidinium improved trough FEV1 versus placebo in ACCLAIM/COPD I (by 61 and 67 mL; both p<0.001) and ACCLAIM/COPD II (by 63 and 59 mL; both p<0.001). More patients had a SGRQ improvement≥4 units at 52 weeks with aclidinium versus placebo in ACCLAIM/COPD I (48.1% versus 39.5%; p=0.025) and ACCLAIM/COPD II (39.0% versus 32.8%; p=0.074). The time to first exacerbation was significantly delayed by aclidinium in ACCLAIM/COPD II (hazard ratio [HR] 0.7; 95% confidence interval [CI] 0.55 to 0.92; p=0.01), but not ACCLAIM/COPD I (HR 1.0; 95% CI 0.72 to 1.33; p=0.9). Adverse events were minor in both studies. CONCLUSION: Aclidinium is effective and well tolerated in patients with moderate to severe COPD