QCD corrections to longitudinal spin asymmetries in W±W^\pm-boson production at RHIC

The polarized antiquark distributions in the proton can be measured by studying spin asymmetries in vector boson production in longitudinally polarized proton-proton collisions. The STAR and PHENIX experiments at BNL RHIC have reported first observations of single spin asymmetries in $W^\pm$-production most recently. We compute the QCD corrections to single and double spin asymmetries, taking account of the leptonic decay of the $W^\pm$ boson and of restrictions on the kinematical acceptance of the detectors. The QCD corrections have only a small impact on the asymmetries, such that a reliable extraction of the polarized antiquark distributions can be envisaged once more precise measurements are made.Comment: LaTeX, 12 pages, typos corrected, references adde

Endoscopic endodontic microsurgery: 2-year evaluation of healing and functionality.

This prospective clinical study aimed to evaluate the benefits of the endoscope as an aid to root-end management, and to assess the treatment outcome during 2 years following surgery. Forty-three endodontic surgical procedures in 30 patients were performed with the aid of an endoscope and followed for a period of 2 years. Radiographic criteria and clinical evaluation were used to assess the outcome. All cases were evaluated in terms of healing and functionality. 91.1% and 90.7% of the teeth evaluated after 1 and 2 years, respectively, were classified as successful. We found no statistically significant differences for both healing and functionality between the 1- and 2-year evaluations. No difference related to tooth type or tooth location was found at the 2-year follow-up. Fisher's exact test was used to statistically assess the difference between successful and unsuccessful cases for each of the variables considered. The endoscope can be an aid for endodontic surgical procedures in terms of both periapical healing and functionality up to 2 years follow-up

Guided tissue regeneration using a barrier membrane in endodontic surgery

Endodontic surgery aims at the resolution of a periapical inflammatory process by surgical access followed by enucleation of the lesion and root-end filling to curb any potentially noxious agent within the physical confines of the affected root. Guided bone regeneration could be associated to endodontic surgery aiming to enhance periradicular tissue regeneration. The objective of this paper was to review the scientific literature about guided bone regeneration in endodontic surgery, evaluating the effects on periapical lesion healing process. The included articles are classified considering the anatomical characteristics of the lesion. Fourteen articles were included in the review after abstract and title selection. Eight articles were on studies on lesions affecting only the periapical region (three about through-and-through lesions) while six were about the treatment of apico-marginal lesions. On the basis of the currently available literature, there is a low scientific evidence of a benefit related. to the use of guided bone regeneration procedure in endodontic surgery

Hudson '70 : gravity observations 62.9S̊ - 57.5N̊ along 150W̊

To provide geoidal topography over the world oceans, a radar altimeter carried by earth satellite is planned. Ground truth calibration will be provided by a grid comprised of the equatorial belt and meridional traverses along the 30°W and 150°W meridians. Ground truth topography is derived from gravity values measured along these traverses. This report presents the free air gravity values and the computed free air anomalies obtained from 62.9°S to 57.5°N along the 150°W meridian.Supported by the Office of Naval Research under Contract N00014-66-C0241; NR 083-004

Regularization in quantum field theory from the causal point of view

The causal approach to perturbative quantum field theory is presented in detail, which goes back to a seminal work by Henri Epstein and Vladimir Jurko Glaser in 1973. Causal perturbation theory is a mathematically rigorous approach to renormalization theory, which makes it possible to put the theoretical setup of perturbative quantum field theory on a sound mathematical basis. Epstein and Glaser solved this problem for a special class of distributions, the time-ordered products, that fulfill a causality condition, which itself is a basic requirement in axiomatic quantum field theory. In their original work, Epstein and Glaser studied only theories involving scalar particles. In this review, the extension of the method to theories with higher spin, including gravity, is presented. Furthermore, specific examples are presented in order to highlight the technical differences between the causal method and other regularization methods, like, e.g. dimensional regularization.Comment: 75 pages, 8 figures, style file included, some comments and references adde

Fate of charge order in overdoped La-based cuprates

In high-temperature cuprate superconductors, stripe order refers broadly to a coupled spin and charge modulation with a commensuration of eight and four lattice units, respectively. How this stripe order evolves across optimal doping remains a controversial question. Here we present a systematic resonant inelastic x-ray scattering study of weak charge correlations in La$_{2−x}$Sr$_{x}$CuO$_{4}$ and La$_{1.8−x}$Eu$_{0.2}$Sr$_{x}$CuO$_{4}$. Ultra high energy resolution experiments demonstrate the importance of the separation of inelastic and elastic scattering processes. Long-range temperature-dependent stripe order is only found below optimal doping. At higher doping, short-range temperature-independent correlations are present up to the highest doping measured. This transformation is distinct from and preempts the pseudogap critical doping. We argue that the doping and temperature-independent short-range correlations originate from unresolved electron–phonon coupling that broadly peaks at the stripe ordering vector. In La$_{2−x}$Sr$_{x}$CuO$_{4}$, long-range static stripe order vanishes around optimal doping and we discuss both quantum critical and crossover scenarios

Long-term soil water limitation and previous tree vigor drive local variability of drought-induced crown dieback in Fagus sylvatica.

Ongoing climate warming is increasing evapotranspiration, a process that reduces plant-available water and aggravates the impact of extreme droughts during the growing season. Such an exceptional hot drought occurred in Central Europe in 2018 and caused widespread defoliation in mid-summer in European beech (Fagus sylvatica L.) forests. Here, we recorded crown damage in 2021 in nine mature even-aged beech-dominated stands in northwestern Switzerland along a crown damage severity gradient (low, medium, high) and analyzed tree-ring widths of 21 mature trees per stand. We aimed at identifying predisposing factors responsible for differences in crown damage across and within stands such as tree growth characteristics (average growth rates and year-to-year variability) and site-level variables (mean canopy height, soil properties). We found that stand-level crown damage severity was strongly related to soil water availability, inferred from tree canopy height and plant available soil water storage capacity (AWC). Trees were shorter in drier stands, had higher year-to-year variability in radial growth, and showed higher growth sensitivity to moisture conditions of previous late summer than trees growing on soils with sufficient AWC, indicating that radial growth in these forests is principally limited by soil water availability. Within-stand variation of post-drought crown damage corresponded to growth rate and tree size (diameter at breast height, DBH), i.e., smaller and slower-growing trees that face more competition, were associated with increased crown damage after the 2018 drought. These findings point to tree vigor before the extreme 2018 drought (long-term relative growth rate) as an important driver of damage severity within and across stands. Our results suggest that European beech is less likely to be able to cope with future climate change-induced extreme droughts on shallow soils with limited water retention capacity

Uniaxial pressure induced stripe order rotation in La1.88Sr0.12CuO4

Static stripe order is detrimental to superconductivity. Yet, it has been proposed that transverse stripe fluctuations may enhance the inter-stripe Josephson coupling and thus promote superconductivity. Direct experimental studies of stripe dynamics, however, remain difficult. From a strong-coupling perspective, transverse stripe fluctuations are realized in the form of dynamic “kinks”—sideways shifting stripe sections. Here, we show how modest uniaxial pressure tuning reorganizes directional kink alignment. Our starting point is La1.88Sr0.12CuO4 where transverse kink ordering results in a rotation of stripe order away from the crystal axis. Application of mild uniaxial pressure changes the ordering pattern and pins the stripe order to the crystal axis. This reordering occurs at a much weaker pressure than that to detwin the stripe domains and suggests a rather weak transverse stripe stiffness. Weak spatial stiffness and transverse quantum fluctuations are likely key prerequisites for stripes to coexist with superconductivity