1,799 research outputs found

    Effect of the Photon's Brownian Doppler Shift on the Weak-Localization Coherent-Backscattering Cone

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    We report the first observation of the dependence of the coherent-backscattering (CBS) enhanced cone with the frequency of the backscattered photon. The experiment is performed on a diffusing liquid suspension and the Doppler broadening of light is induced by the Brownian motion of the scatterers. Heterodyne detection on a CCD camera is used to measure the complex field (i.e., the hologram) of the light that is backscattered at a given frequency. The analysis of the holograms yield the frequency and the propagation direction of the backscattered photons. We observe that the angular CBS cone becomes more narrow in the tail of the Brownian spectrum. The experimental results are in good agreement with a simple theoretical model

    Multicenter experience of upper extremity access in complex endovascular aortic aneurysm repair

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    Purpose: Upper extremity access (UEA) for antegrade cannulation of aortic side branches is a relevant part of endovascular treatment of complex aortic aneurysms and can be achieved using several techniques, sites, and sides. The purpose of this study was to evaluate different UEA strategies in a multicenter registry of complex endovascular aortic aneurysm repair (EVAR). Methods: In six aortic centers in the Netherlands, all endovascular aortic procedures from 2006 to 2019 were retrospectively reviewed. Patients who received UEA during complex EVAR were included. The primary outcome was a composite end point of any access complication, excluding minor hematomas. Secondary outcomes were access characteristics, access complications considered individually, access reinterventions, and incidence of ischemic cerebrovascular events. Results: A total of 417 patients underwent 437 UEA for 303 fenestrated/branched EVARs and 114 chimney EVARs. Twenty patients had bilateral, 295 left-sided, and 102 right-sided UEA. A total of 413 approaches were performed surgically and 24 percutaneously. Distal brachial access (DBA) was used in 89 cases, medial brachial access (MBA) in 149, proximal brachial access (PBA) in 140, and axillary access (AA) in 59 cases. No significant differences regarding the composite end point of access complications were seen (DBA: 11.3% vs MBA: 6.7% vs PBA: 13.6% vs AA: 10.2%; P =.29). Postoperative neuropathy occurred most after PBA (DBA: 1.1% vs MBA: 1.3% vs PBA: 9.3% vs AA: 5.1%; P =.003). There were no differences in cerebrovascular complications between access sides (right: 5.9% vs left: 4.1% vs bilateral: 5%; P =.75). Significantly more overall access complications were seen after a percutaneous approach (29.2% vs 6.8%; P =.002). In multivariate analysis, the risk for access complications after an open approach was decreased by male sex (odds ratio [OR]: 0.27; 95% confidence interval [CI]: 0.10-0.72; P =.009), whereas an increase in age per year (OR: 1.08; 95% CI: 1.004-1.179; P =.039) and diabetes mellitus type 2 (OR: 3.70; 95% CI: 1.20-11.41; P =.023) increased the risk. Conclusions: Between the four access localizations, there were no differences in overall access complications. Female sex, diabetes mellitus type 2, and aging increased the risk for access complications after a surgical approach. Furthermore, a percutaneous UEA resulted in higher complication rates than a surgical approach

    Anatomy of a post-starburst minor merger: a multi-wavelength WFC3 study of NGC 4150

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    (Abridged) We present a spatially-resolved near-UV/optical study of NGC 4150, using the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. Previous studies of this early-type galaxy (ETG) indicate that it has a large reservoir of molecular gas, exhibits a kinematically decoupled core (likely indication of recent merging) and strong, central H_B absorption (indicative of young stars). The core of NGC 4150 shows ubiquitous near-UV emission and remarkable dusty substructure. Our analysis shows this galaxy to lie in the near-UV green valley, and its pixel-by-pixel photometry exhibits a narrow range of near-UV/optical colours that are similar to those of nearby E+A (post-starburst) galaxies. We parametrise the properties of the recent star formation (age, mass fraction, metallicity and internal dust content) in the NGC 4150 pixels by comparing the observed near-UV/optical photometry to stellar models. The typical age of the recent star formation (RSF) is around 0.9 Gyrs, consistent with the similarity of the near-UV colours to post-starburst systems, while the morphological structure of the young component supports the proposed merger scenario. The RSF metallicity, representative of the metallicity of the gas fuelling star formation, is around 0.3 - 0.5 Zsun. Assuming that this galaxy is a merger and that the gas is sourced mainly from the infalling companion, these metallicities plausibly indicate the gas-phase metallicity (GPM) of the accreted satellite. Comparison to the local mass-GPM relation suggests (crudely) that the mass of the accreted system is around 3x10^8 Msun, making NGC 4150 a 1:20 minor merger. A summation of the pixel RSF mass fractions indicates that the RSF contributes about 2-3 percent of the stellar mass. This work reaffirms our hypothesis that minor mergers play a significant role in the evolution of ETGs at late epochs.Comment: 28 pages, 2 tables, accepted for publication in Ap

    Mapping physiological G protein-coupled receptor signaling pathways reveals a role for receptor phosphorylation in airway contraction.

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    G protein-coupled receptors (GPCRs) are known to initiate a plethora of signaling pathways in vitro. However, it is unclear which of these pathways are engaged to mediate physiological responses. Here, we examine the distinct roles of Gq/11-dependent signaling and receptor phosphorylation-dependent signaling in bronchial airway contraction and lung function regulated through the M3-muscarinic acetylcholine receptor (M3-mAChR). By using a genetically engineered mouse expressing a G protein-biased M3-mAChR mutant, we reveal the first evidence, to our knowledge, of a role for M3-mAChR phosphorylation in bronchial smooth muscle contraction in health and in a disease state with relevance to human asthma. Furthermore, this mouse model can be used to distinguish the physiological responses that are regulated by M3-mAChR phosphorylation (which include control of lung function) from those responses that are downstream of G protein signaling. In this way, we present an approach by which to predict the physiological/therapeutic outcome of M3-mAChR-biased ligands with important implications for drug discovery.This study is funded by the Medical Research Council (MRC) through funding of program leaders provided by the MRC Toxicology Unit (to A.B.T.)

    Resistance training in humans and mechanical overload in rodents do not elevate muscle protein lactylation

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    Although several reports have hypothesized that exercise may increase skeletal muscle protein lactylation, empirical evidence in humans is lacking. Thus, we adopted a multifaceted approach to examine if acute and subchronic resistance training (RT) altered skeletal muscle protein lactylation levels. In mice, we also sought to examine if surgical ablation-induced plantaris hypertrophy coincided with increases in muscle protein lactylation. To examine acute responses, participants’ blood lactate concentrations were assessed before, during, and after eight sets of an exhaustive lower body RT bout (n = 10 trained college-aged men). Vastus lateralis biopsies were also taken before, 3-h post, and 6-h post-exercise to assess muscle protein lactylation. To identify training responses, another cohort of trained college-aged men (n = 14) partook in 6 weeks of lower-body RT (3x/week) and biopsies were obtained before and following the intervention. Five-month-old C57BL/6 mice were subjected to 10 days of plantaris overload (OV, n = 8) or served as age-matched sham surgery controls (Sham, n = 8). Although acute resistance training significantly increased blood lactate responses ~7.2- fold (p \u3c 0.001), cytoplasmic and nuclear protein lactylation levels were not significantly altered at the post-exercise time points, and no putative lactylation-dependent mRNA was altered following exercise. Six weeks of RT did not alter cytoplasmic protein lactylation (p = 0.800) despite significantly increasing VL muscle size (+3.5%, p=0.037), and again, no putative lactylation-dependent mRNA was significantly affected by training. Plantaris muscles were larger in OV versus Sham mice (+43.7%, p \u3c 0.001). However, cytoplasmic protein lactylation was similar between groups (p = 0.369), and nuclear protein lactylation was significantly lower in OV versus Sham mice (p \u3c 0.001). The current null findings, along with other recent null findings in the literature, challenge the thesis that lactate has an appreciable role in promoting skeletal muscle hypertrophy

    Constitutional Ethnography: An Introduction

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    Constitutional ethnography is the study of the central legal elements of polities using methods that are capable of recovering the lived detail of the politico-legal landscape. This article provides an introduction to this sort of study by contrasting constitutional ethnography with multivariate analysis and with nationalist constitutional analysis. The article advocates not a universal one-size-fits-all theory or an elegant model that abstracts away the distinctive, but instead outlines an approach that can identify a set of repertoires found in real cases. Learning the set of repertoires that constitutional ethnography reveals, one can see more deeply into particular cases. Constitutional ethnography has as its goal, then, not prediction but comprehension, not explained variation but thematization

    In the dedicated pursuit of dedicated capital: restoring an indigenous investment ethic to British capitalism

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    Tony Blair’s landslide electoral victory on May 1 (New Labour Day?) presents the party in power with a rare, perhaps even unprecedented, opportunity to revitalise and modernise Britain’s ailing and antiquated manufacturing economy.* If it is to do so, it must remain true to its long-standing (indeed, historic) commitment to restore an indigenous investment ethic to British capitalism. In this paper we argue that this in turn requires that the party reject the very neo-liberal orthodoxies which it offered to the electorate as evidence of its competence, moderation and ‘modernisation’, which is has internalised, and which it apparently now views as circumscribing the parameters of the politically and economically possible

    Binary and Millisecond Pulsars at the New Millennium

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    We review the properties and applications of binary and millisecond pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1300. There are now 56 binary and millisecond pulsars in the Galactic disk and a further 47 in globular clusters. This review is concerned primarily with the results and spin-offs from these surveys which are of particular interest to the relativity community.Comment: 59 pages, 26 figures, 5 tables. Accepted for publication in Living Reviews in Relativity (http://www.livingreviews.org

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 6060^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law EγE^{-\gamma} with index γ=2.70±0.02(stat)±0.1(sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)1.2+1.0(sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO
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