149 research outputs found
Strange Quark Contribution to the Proton Spin, from Elastic and Scattering
The strangeness contribution to the vector and axial form factors of the
proton is presented for momentum transfers in the range 0.45 < < 1.0
GeV. The results are obtained via a combined analysis of forward-scattering
parity-violating elastic asymmetry data from the G0 and HAPPEx
experiments at Jefferson Lab, and elastic and scattering
data from Experiment 734 at Brookhaven National Laboratory. The combination of
the two data sets allows for the simultaneous extraction of , ,
and over a significant range of for the very first time.
Determination of the strange axial form factor is vital to an
understanding of the strange quark contribution to the proton spin.Comment: 4 pages, 1 figure; proceedings for SPIN 2006; will be published in
AIP Conference Proceeding
PHENIX Measurement of Parity-Violating Single Spin Asymmetry in W Production in p+p Collisions at 500 GeV
The flavor-separated polarized parton distribution functions for light quarks
and anti-quarks in the proton can be studied in the production of bosons in
+ collisions. The s are produced in processes like
and and we observe the
lepton (an electron or muon) from the decay channel . The electron energy spectrum from decays measured with an
integrated luminosity of approximately 10 pb will be shown, with a
measurement of the electron single spin asymmetry in central rapidity.Comment: Proceedings of the DIFFRACTION 2010 Conference; 4 pages, 2 figure
Progress On Neutrino-Proton Neutral-Current Scattering In MicroBooNE
The MicroBooNE Experiment at the Fermi National Accelerator Laboratory, an
89-ton active mass liquid argon time projection chamber, affords a unique
opportunity to observe low- neutral-current neutrino-proton scattering
events. Neutral-current neutrino-proton scattering at GeV is
dominated by the proton's axial form factor, which can be written as a
combination of contributions from the up, down, and strange quarks: . The contribution from up and
down quarks has been established in past charged-current measurements. The
contribution from strange quarks at low remains unmeasured; this is of
great interest since the strange quark contribution to the proton spin can be
determined from the low- behavior: . MicroBooNE
began operating in the Booster Neutrino Beam in October 2015. I will present
the status in observing isolated proton tracks in the MicroBooNE detector as a
signature for neutral-current neutrino-proton events. The sensitivity of the
MicroBooNE experiment for measuring the strange quark contribution to the
proton spin will be discussed.Comment: Proceedings for the 26th International Nuclear Physics Conference,
11-16 September, 2016, Adelaide, Australi
Multisite study assessing the effect of cognitive test anxiety on academic and standardized test performance
Objective. To evaluate the degree of cognitive test anxiety (CTA) present in student pharmacists at multiple pharmacy programs in the United States and to determine if there are associations between self-reported CTA and relevant academic outcomes. Methods. All 2018-2019 advanced pharmacy practice experience (APPE) students from three US Doctor of Pharmacy (PharmD) programs (N=260) were invited to participate in the study. Participants completed a validated 37-question survey that included the Cognitive Test Anxiety Scale-2 (CTAS-2) along with demographics-related questions. Responses were analyzed using analysis of variance (ANOVA), Kruskal Wallace, and multiple linear regression where appropriate. Results. One hundred twenty-four students (48%) from the three programs participated in the study, and the individual data of 119 (46%) were included in the final analysis. Twenty-two students (18.5%) were classified as having high CTA, 41 (34.5%) as having moderate CTA, and 56 (47.1%) as having low CTA. High CTA predicted a 8.9 point lower NAPLEX total scaled score after accounting for other variables and was also correlated with lower cumulative didactic GPA, performance on the Pharmacy Curriculum Outcomes Assessment (PCOA), and increased likelihood of requiring course remediation. Conclusion. High cognitive test anxiety affects 18% of pharmacy students and may significantly impact their performance on a variety of traditional student success measures, including the NAPLEX. Pharmacy educators should consider further use and adoption of test anxiety measurements to identify and assist potentially struggling students
Initiation of antihypertensive monotherapy and incident fractures among Medicare beneficiaries
Abstract Background Research suggests antihypertensive medications are associated with fractures in older adults, however results are inconsistent and few have examined how the association varies over time. We sought to examine the association between antihypertensive class and incident non-vertebral fractures among older adults initiating monotherapy according to time since initiation. Methods We used a new-user cohort design to identify Medicare beneficiaries (⼠65 years of age) initiating antihypertensive monotherapy during 2008â2011 using a 20% random sample of Fee-For-Service Medicare beneficiaries enrolled in parts A (inpatient services), B (outpatient services), and D (prescription medication) coverage. Starting the day after the initial antihypertensive prescription, we followed beneficiaries for incident non-vertebral fractures. We used multinomial logistic regression models to estimate propensity scores for initiating each antihypertensive drug class. Using these propensity scores, we weighted beneficiaries to achieve the same baseline covariate distribution as beneficiaries initiating with angiotensin-converting enzyme inhibitors. Lastly, we used weighted Cox proportional hazard models to estimate hazard ratios (HRs) of having an incident fractures according to antihypertensive class and time since initiation. Results During 2008â2011, 122,629 Medicare beneficiaries initiated antihypertensive monotherapy (mean age 75, 61% women, 86% White). Fracture rates varied according to days since initiation and antihypertensive class. Beneficiaries initiating with thiazides had the highest fracture rate in the first 14 days following initiation (438 per 10,000 person-years, 95% confidence interval (CI): 294â628; HR: 1.40, 0.78â2.52). However, beneficiaries initiating with calcium channel blockers had the highest fracture rate during the 15â365 days after initiation (435 per 10,000 person-years, 95% CI: 404â468; HR: 1.11, 1.00â1.24). Beneficiaries initiating with angiotensin-receptor blockers had the lowest fracture rates during the initial 14 days (333 per 10,000 person-years, 190â546, HR: 0.92, 0.49â1.75) and during 15â365 days after initiation (321 per 10,000 person-years, 287â358, HR: 0.96, 0.84â1.09). Conclusion The association between antihypertensives and fractures varied according to class and time since initiation. Results suggest that when deciding upon antihypertensive therapy, clinicians may want to consider possible fracture risks when choosing between antihypertensive drug classes
Operational Implementation of the Healthy Communities Study How Communities Shape Childrenâs Health
The Healthy Communities Study (HCS) is examining how characteristics of community programs and policies targeting childhood obesity are related to childhood diet, physical activity, and obesity outcomes. The study involves selected districts and public schools in 130 communities; families recruited through schools; and data collected at the community, school, household, and child levels. Data collection took place in two wavesâWave 1 in Spring 2012 and Wave 2 from 2013 to 2015âwith analysis to be completed by August 2016. This paper describes operational elements of the HCS, including recruitment activities, field operations, training of data collectors, human subjects protection, and quality assurance and quality control procedures. Experienced trainers oversaw and conducted all training, including training of: (1) district and school recruitment staff; (2) telephone interviewers for household screening and recruitment; (3) field data collectors for conducting household data collection; and (4) community liaisons for conducting key informant interviews, document abstraction, and community observations. The study team developed quality assurance and quality control procedures that were implemented for all aspects of the study. Planning and operationalizing a study of this complexity and magnitude, with multiple functional teams, required frequent communication and strong collaboration among all study partners to ensure timely and effective decision making
Delays in Leniency Application: Is There Really a Race to the Enforcer's Door?
This paper studies cartelsâ strategic behavior in delaying leniency applications, a take-up decision that has been ignored in the previous literature. Using European Commission decisions issued over a 16-year span, we show, contrary to common beliefs and the existing literature, that conspirators
often apply for leniency long after a cartel collapses. We estimate hazard and probit models to study the determinants of leniency-application delays. Statistical tests find that delays are symmetrically affected by antitrust policies and macroeconomic fluctuations. Our results shed light on the design of
enforcement programs against cartels and other forms of conspiracy
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