O(αsv2)O(\alpha_s v^2) correction to pseudoscalar quarkonium decay to two photons

We investigate the $O(\alpha_s v^2)$ correction to the process of pseudoscalar quarkonium decay to two photons in nonrelativistic QCD (NRQCD) factorization framework. The short-distance coefficient associated with the relative-order $v^2$ NRQCD matrix element is determined to next-to-leading order in $\alpha_s$ through the perturbative matching procedure. Some technical subtleties encountered in calculating the {O(\alpha_s) QCD amplitude are thoroughly addressed.Comment: v2, 28 pages, 2 figures and 2 tables, matching the published version; typos corrected, references added, as well as a "Note added in the proof

Association between clean delivery kit use, clean delivery practices, and neonatal survival: pooled analysis of data from three sites in South Asia

Sepsis accounts for up to 15% of an estimated 3.3 million annual neonatal deaths globally. We used data collected from the control arms of three previously conducted cluster-randomised controlled trials in rural Bangladesh, India, and Nepal to examine the association between clean delivery kit use or clean delivery practices and neonatal mortality among home births

State of newborn care in South Sudan’s displacement camps: a descriptive study of facility-based deliveries

BACKGROUND: Approximately 2.7 million neonatal deaths occur annually, with highest rates of neonatal mortality in countries that have recently experienced conflict. Constant instability in South Sudan further strains a weakened health system and poses public health challenges during the neonatal period. We aimed to describe the state of newborn facility-level care in displaced person camps across Juba, Malakal, and Maban. METHODS: We conducted clinical observations of the labor and delivery period, exit interviews with recently delivered mothers, health facility assessments, and direct observations of midwife time-use. Study participants were mother-newborn pairs who sought services and birth attendants who provided delivery services between April and June 2016 in five health facilities. RESULTS: Facilities were found to be lacking the recommended medical supplies for essential newborn care. Two of the five facilities had skilled midwives working during all operating hours, with 6.2% of their time spent on postnatal care. Selected components of thermal care (62.5%), infection prevention (74.8%), and feeding support (63.6%) were commonly practiced, but postnatal monitoring (27.7%) was less consistently observed. Differences were found when comparing the primary care level to the hospital (thermal: relative risk [RR] 0.48 [95% CI] 0.40–0.58; infection: RR 1.28 [1.11–1.47]; feeding: RR 0.49 [0.40–0.58]; postnatal: RR 3.17 [2.01–5.00]). In the primary care level, relative to newborns delivered by traditional birth attendants, those delivered by skilled attendants were more likely to receive postnatal monitoring (RR 1.59 [1.09-2. 32]), but other practices were not statistically different. Mothers’ knowledge of danger signs was poor, with fever as the highest reported (44.8%) followed by not feeding well (41.0%), difficulty breathing (28.9%), reduced activity (27.7%), feeling cold (18.0%) and convulsions (11.2%). CONCLUSIONS: Addressing health service delivery in contexts affected by conflict is vital to reducing the global newborn mortality rate and reaching the Sustainable Development Goals. Gaps in intrapartum and postnatal care, particularly skilled care at birth, suggest a critical need to build the capacity of the existing health workforce while increasing access to skilled deliveries.IS

The role of metal hydroxide complexes in late transition metal-mediated transmetalation reaction : the case of gold

In gold chemistry, the hydroxide function on the metal center was observed to act as a potent transmetalation group facilitator when reacted with boronic acids leading to the exceedingly rapid formation of gold-aryl bonds

Sensitive X-ray detectors made of methylammonium lead tribromide perovskite single crystals

The large mobilities and carrier lifetimes of hybrid perovskite single crystals and the high atomic numbers of Pb, I and Br make them ideal for X-ray and gamma-ray detection. Here, we report a sensitive X-ray detector made of methylammonium lead bromide perovskite single crystals. A record-high mobility-lifetime product of 1.2 x 10(-2) cm(2) V-1 and an extremely small surface charge recombination velocity of 64 cm s(-1) are realized by reducing the bulk defects and passivating surface traps. Single-crystal devices with a thickness of 2-3 mm show 16.4% detection efficiency at near zero bias under irradiation with continuum X-ray energy up to 50 keV. The lowest detectable X-ray dose rate is 0.5 mu Gy(air) s(-1) with a sensitivity of 80 mu C Gy(air)(-1) cm(-2), which is four times higher than the sensitivity achieved with alpha-Se X-ray detectors. This allows the radiation dose applied to a human body to be reduced for many medical and security check applications

Fractal morphology, imaging and mass spectrometry of single aerosol particles in flight

The morphology of micrometre-size particulate matter is of critical importance in fields ranging from toxicology to climate science, yet these properties are surprisingly difficult to measure in the particles' native environment. Electron microscopy requires collection of particles on a substrate; visible light scattering provides insufficient resolution; and X-ray synchrotron studies have been limited to ensembles of particles. Here we demonstrate an in situ method for imaging individual sub-micrometre particles to nanometre resolution in their native environment, using intense, coherent X-ray pulses from the Linac Coherent Light Source free-electron laser. We introduced individual aerosol particles into the pulsed X-ray beam, which is sufficiently intense that diffraction from individual particles can be measured for morphological analysis. At the same time, ion fragments ejected from the beam were analysed using mass spectrometry, to determine the composition of single aerosol particles. Our results show the extent of internal dilation symmetry of individual soot particles subject to non-equilibrium aggregation, and the surprisingly large variability in their fractal dimensions. More broadly, our methods can be extended to resolve both static and dynamic morphology of general ensembles of disordered particles. Such general morphology has implications in topics such as solvent accessibilities in proteins, vibrational energy transfer by the hydrodynamic interaction of amino acids, and large-scale production of nanoscale structures by flame synthesis