Using π0’s to Understand Proton Spin Structure through Polarized p+p Collisions at 1 \u3c η \u3c 2 and √s = 200 GeV at STAR

Measurements of spin dependent observables at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory provide unique insight into the contribution of a proton\u27s constituents to its spin. The Solenoidal Tracker at RHIC (STAR) can be used to measure effects of the quark and gluon spins in the proton by observations of neutral pions that result from longitudinally and transversely polarized proton-proton collisions in STAR. The neutral pions (π0’s) decay into two photons that, for pseudorapidity (η) 1 to 2, can be observed in the endcap electromagnetic calorimeter in STAR. These are used to reconstruct the kinematic properties of the π0’s and we can then look for spin asymmetries in π0 production. Measurements of both the longitudinal and transverse spin asymmetries in the production of π0’s from data taken in 2006 have made some contributions to our understanding of the structure of the proton. New data taken in 2009, in a longitudinal spin run with greater luminosity, will provide greater precision in the final results. Results from 2006 (STAR’s most recent spin paper, submitted to Phys. Rev. D: arXiv:1309.1800) and preliminary work on 2009 data are shown

Neutral Pion Asymmetries at Intermediate Pseudorapidity in Transversely Polarized p + p Collisions at √ s = 200 GeV

Among the unanswered questions pertaining to nucleon spin physics is the origin of large azimuthal asymmetries (AN ) found in π forward pseudorapidity, η, from high-energy transversely polarized p + p collisions. One possible explanation is offered by twist-3 parton distribution and fragmentation functions. In order to test these and other mechanisms, it is important to study how the asymmetry changes over a range of pion kinematics. The STAR Endcap Electromagnetic Calorimeter (EEMC) is the only RHIC detector with the ability to study AN for π available at intermediate pseudorapidity, 0.8 ≤ η ≤ 2.0. STAR recently published the first measurement of AN for π using data collected in 2006 with collision energy √ STAR collected a high-statistics dataset with transverse beam polarization at √ s = 200 GeV. This offers over a five-fold increase in integrated luminosity relative to the 2006 dataset and a chance to enhance the precision of the previous results. The primary objective of this study is to determine the quality of the data from 2012 and to estimate the final statistical uncertainty.Preliminary results from this study indicate a significant improvement over the 2006 results

Understanding Proton Spin Structure through Polarized p+p Collisions at 200 GeV at STAR

Measurements of spin observables at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory provide unique insight into the contribution of a proton\u27s constituents to its spin. The Solenoidal Tracker at RHIC (STAR) is sensitive to the proton spin from polarized proton-proton collisions. One of the primary products of these collisions are neutral pions, (π0) which decay into two photons. The photons are reconstructed in the endcap electro-magnetic calorimeter of STAR, and are used to reconstruct the π0 and its properties. Measurements of both the longitudinal and transverse spin asymmetries in the production of π0 from data taken in 2006 have made some contributions in our understanding of the structure of the proton. New data taken in 2009, in an experimental setup resulting in less background and with more statistics, will provide greater precision to the final results. Some results from 2006 and preliminary work on 2009 data will be shown

A First-Principle Study of Small Neutral and Anionic Silver Halide Clusters

Silver halide is a material that was traditionally used in photographic films. In recent years, there has been a revived interest in using small clusters of silver halides for photocatalytic and photovoltaic applications. We present the results of a theoretical study of neutral and anionic AgnXn (X = F, Cl, and Br, and n = 1-6) clusters. Quantum-mechanical calculations were performed using Density Functional Theory (DFT) in search of the lowest-energy isomers of the neutral and anionic clusters with applied symmetry constraints. The optimal configurations are compared across the series of AgF, AgCl, and AgBr. The variation in binding energies, bond lengths, charge distributions, HOMO-LUMO gaps, and electron affinities will be discussed as a function of cluster size and composition. The study of these clusters allows us to gain a better understanding of the structure and function of these materials in current and future applications

Disparities in access to musculoskeletal care: Narrowing the gap: AOA critical issues symposium

The current health-care system in the United States has numerous barriers to quality, accessible, and affordable musculoskeletal care for multiple subgroups of our population. These hurdles include complex cultural, educational, and socioeconomic factors. Tertiary referral centers provide a disproportionately large amount of the care for the uninsured and underinsured members of our society. These gaps in access to care for certain subgroups lead to inappropriate emergency room usage, lengthy hospitalizations, increased administrative load, lost productivity, and avoidable complications and/or deaths, which all represent a needless burden on our health-care system. Through advocacy, policy changes, workforce diversification, and practice changes, orthopaedic surgeons have a responsibility to seek solutions to improve access to quality and affordable musculoskeletal care for the communities that they serve

Neuromuscular responses to mild-muscle damaging eccentric exercise in a low glycogen state.

The aim of this study was to examine the effect of low muscle glycogen on the neuromuscular responses to maximal eccentric contractions. Fourteen healthy men (22±3years) performed single-leg cycling (20min at ∼75% maximal oxygen uptake (V̇O2 max); eight 90 s sprints at a 1:1 work-to-rest ratio (5% decrements from 90% to 55% V̇O2 max until exhaustion) the evening before 100 eccentric (1.57rads(-1)) with reduced (RED) and normal glycogen (NORM). Neuromuscular responses were measured during and up to 48h after with maximal voluntary and involuntary (twitch, 20Hz and 50Hz) isometric contractions. During eccentric contractions, peak torque decreased (RED: -16.1±2.5%; NORM: -6.2±5.1%) and EMG frequency increased according to muscle length. EMG activity decreased for RED only. After eccentric contractions, maximal isometric force was reduced up to 24h for NORM (-13.5±5.8%) and 48h for RED (-7.4±10.9%). Twelve hours after eccentric contractions, twitch force and the 20:50Hz ratio were decreased for RED but not for NORM. Immediate involuntary with prolonged voluntary force loss suggests that reduced glycogen is associated with increased susceptibility to mild muscle-damaging eccentric exercise with contributions of peripheral and central mechanisms to be different during recovery

Science in neo-Victorian poetry

This article considers the work of three contemporary poets and their engagement, in verse, with Victorian science. Beginning with the outlandish ‘theories’ of Mick Imlah’s ‘The Zoologist’s Bath’ (1983), it moves on to two works of biografiction – Anthony Thwaite’s poem ‘At Marychurch’ (1980), which outlines Philip Henry Gosse’s doomed attempts to unite evolution and Christianity, and Ruth Padel’s Darwin: A Life in Poems (2009). Starting off with John Glendening’s idea that science in neo-Victorian fiction, if fully embraced, provides an opportunity for self-revelation to characters, this article explores the rather less happy resolutions of each of these poems, while in addition discussing the ways in which these poems perform the formal changes and mutability discussed within them

Chemical profiles of the oxides on tantalum in state of the art superconducting circuits

Over the past decades, superconducting qubits have emerged as one of the leading hardware platforms for realizing a quantum processor. Consequently, researchers have made significant effort to understand the loss channels that limit the coherence times of superconducting qubits. A major source of loss has been attributed to two level systems that are present at the material interfaces. We recently showed that replacing the metal in the capacitor of a transmon with tantalum yields record relaxation and coherence times for superconducting qubits, motivating a detailed study of the tantalum surface. In this work, we study the chemical profile of the surface of tantalum films grown on c-plane sapphire using variable energy X-ray photoelectron spectroscopy (VEXPS). We identify the different oxidation states of tantalum that are present in the native oxide resulting from exposure to air, and we measure their distribution through the depth of the film. Furthermore, we show how the volume and depth distribution of these tantalum oxidation states can be altered by various chemical treatments. By correlating these measurements with detailed measurements of quantum devices, we can improve our understanding of the microscopic device losses

More than just trees: Assessing reforestation success in tropical developing countries

Rural communities in many parts of the tropics are dependent of forests for their livelihoods and for environmental services. Forest resources in the tropics have declined rapidly over the past century and therefore many developing countries in the tropics have reforestation programs. Although reforestation is a long-term process with long-term benefits, existing evaluations of the success of these programs tends to focus on short-term establishment success indicators. This paper presents a review of reforestation assessment that highlights the need to not only consider short-term establishment success, but also longer-term growth and maturation success, environmental success and socio-economic success. In addition, we argue that reforestation assessment should not be based on success indicators alone, but should incorporate the drivers of success, which encompasses an array of biophysical, socio-economic, institutional and project characteristics. This is needed in order to understand the reasons why reforestation projects succeed or fail and therefore to design more successful projects in future. The paper presents a conceptual model for reforestation success assessment that links key groups of success indicators and drivers. This conceptual model provides the basis for a more comprehensive evaluation of reforestation success and the basis for the development of predictive systems-based assessment models. These models will be needed to better guide reforestation project planning and policy design and therefore assist rural communities in tropical developing countries to alleviate poverty and achieve a better quality of life