347 research outputs found
Athletic Ticket Pricing in the Collegiate Environment: An Agenda for Research
s pressure mounts for intercollegiate athletic departments to be more selfsufficient, administrators must respond by increasing generated revenues. Despite the importance of ticket sales in this endeavor, however, little is known about the underlying ticket pricing structures and policies used by National Collegiate Athletic Association (NCAA) institutions. Of the limited existing scholarship focused on managerial pricing decisions in the field of sport management, only professional sports settings have been addressed. Given the unique operational differences between professional and intercollegiate sport, this paper is designed to establish a foundation from which to build future research concerning the pricing of college sport tickets. The frameworks of stakeholder theory and institutional theory are proposed to ground future study in an attempt to strengthen our understanding of the process and behavior of price setting in intercollegiate athletics
A Qualitative Exploration of Ticket-Pricing Decisions in Intercollegiate Athletics
Ticket sales represent a significant revenue stream for NCAA Football Bowl Subdivision athletic departments, yet little is known about how administrators determine prices for those tickets. Utilizing strategic planning as the primary framework and supplemented by stakeholder theory, this study examines ticket-pricing decisions from the viewpoint of athletic administrators with various departmental responsibilities to better understand the role of ticket pricing in intercollegiate sport. Twenty athletic administrators, representing two Power 5 and two Group of 5 institutions, were interviewed about their experiences with ticket pricing. In addition to common pricing objectives related to revenue, patronage, and operations, administrators also suggested attendance-oriented pricing objectives unique to college sport pricing theory. However, findings suggest no well-defined organizational objective for ticket pricing exists within the departments sampled. The factors athletic administrators consider when contemplating pricing decisions can be categorized into seven areas: (a) scheduling, (b) research, (c) team performance, (d) stakeholders, (e) discrimination, (f) fan experience, and (g) competitive comparisons
Athletic Ticket Pricing in the Collegiate Environment: An Agenda for Research
As pressure mounts for intercollegiate athletic departments to be more selfsufficient, administrators must respond by increasing generated revenues. Despite the importance of ticket sales in this endeavor, however, little is known about the underlying ticket pricing structures and policies used by National Collegiate Athletic Association (NCAA) institutions. Of the limited existing scholarship focused on managerial pricing decisions in the field of sport management, only professional sports settings have been addressed. Given the unique operational differences between professional and intercollegiate sport, this paper is designed to establish a foundation from which to build future research concerning the pricing of college sport tickets. The frameworks of stakeholder theory and institutional theory are proposed to ground future study in an attempt to strengthen our understanding of the process and behavior of price setting in intercollegiate athletics
Cold Helium Pressurization for Liquid Oxygen / Liquid Methane Propulsion Systems: Fully-Integrated Initial Hot-Fire Test Results
A prototype cold helium active pressurization system was incorporated into an existing liquid oxygen (LOX) / liquid methane (LCH4) prototype planetary lander and hot-fire tested to collect vehicle-level performance data. Results from this hot-fire test series were used to validate integrated models of the vehicle helium and propulsion systems and demonstrate system effectiveness for a throttling lander. Pressurization systems vary greatly in complexity and efficiency between vehicles, so a pressurization performance metric was also developed as a means to compare different active pressurization schemes. This implementation of an active repress system is an initial sizing draft. Refined implementations will be tested in the future, improving the general knowledge base for a cryogenic lander-based cold helium system
The distribution of transit durations for Kepler planet candidates and implications for their orbital eccentricities
‘In these times, during the rise in the popularity of institutional repositories, the Society does not forbid authors from depositing their work in such repositories. However, the AAS regards the deposit of scholarly work in such repositories to be a decision of the individual scholar, as long as the individual's actions respect the diligence of the journals and their reviewers.’ Original article can be found at : http://iopscience.iop.org/ Copyright American Astronomical SocietyDoppler planet searches have discovered that giant planets follow orbits with a wide range of orbital eccentricities, revolutionizing theories of planet formation. The discovery of hundreds of exoplanet candidates by NASA's Kepler mission enables astronomers to characterize the eccentricity distribution of small exoplanets. Measuring the eccentricity of individual planets is only practical in favorable cases that are amenable to complementary techniques (e.g., radial velocities, transit timing variations, occultation photometry). Yet even in the absence of individual eccentricities, it is possible to study the distribution of eccentricities based on the distribution of transit durations (relative to the maximum transit duration for a circular orbit). We analyze the transit duration distribution of Kepler planet candidates. We find that for host stars with T > 5100 K we cannot invert this to infer the eccentricity distribution at this time due to uncertainties and possible systematics in the host star densities. With this limitation in mind, we compare the observed transit duration distribution with models to rule out extreme distributions. If we assume a Rayleigh eccentricity distribution for Kepler planet candidates, then we find best fits with a mean eccentricity of 0.1-0.25 for host stars with T ≤ 5100 K. We compare the transit duration distribution for different subsets of Kepler planet candidates and discuss tentative trends with planetary radius and multiplicity. High-precision spectroscopic follow-up observations for a large sample of host stars will be required to confirm which trends are real and which are the results of systematic errors in stellar radii. Finally, we identify planet candidates that must be eccentric or have a significantly underestimated stellar radius.Peer reviewedFinal Accepted Versio
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Missed Visits Associated With Future Preexposure Prophylaxis (PrEP) Discontinuation Among PrEP Users in a Municipal Primary Care Health Network
BackgroundMaintaining retention in preexposure prophylaxis (PrEP) care among diverse patient populations will be needed to support PrEP's efficacy. We characterized patterns of PrEP care retention in a US municipal primary care health network and examined whether missed visits, a metric of care retention that is easy to evaluate in clinic, are associated with subsequent discontinuation.MethodsWe included individuals on PrEP from July 2012 until August 2017 in the San Francisco Primary Care Clinics, a 15-clinic municipal health network. We categorized PrEP usage patterns as follows: early discontinuation (<90 days), later discontinuation (after ≥90 days), and continuing use at the end of follow-up. We first examined early discontinuation using adjusted Poisson regression. In patients who continued PrEP for ≥90 days, we examined factors associated with late discontinuation.ResultsOf the 364 individuals who started PrEP, 16% discontinued PrEP before 90 days, 46% discontinued later, and 38% were retained in care over a median 12 months of observation. Transgender women were more likely to discontinue PrEP early (adjusted risk ratio; 2.16; 95% confidence interval, 1.36-3.49), and younger users were more likely to discontinue late (0.82 per 10-year increase in age; .70-.96), as were persons who use illicit drugs (1.59; 1.02-2.47). Missed visits during use of PrEP were associated with future discontinuation (adjusted risk ratio, 1.52; 95% confidence interval, 1.14-2.03). Later year of current PrEP use was associated with both early and late discontinuation.ConclusionDiverse populations may require differentiated care to continue PrEP. Missed visits should trigger tailored interventions to maximize the impact of PrEP
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Brief Report
BackgroundTimely pre-exposure prophylaxis (PrEP) initiation is critical in at-risk populations, given that HIV acquisition risk persists during delays. Time to treatment initiation, a key metric in HIV care, has not been explored among PrEP users. Interventions that reduce time to PrEP initiation could prevent HIV infections.SettingIndividuals initiating PrEP in a large primary care health network of 15 clinics, the San Francisco Primary Care Clinics (SFPCC), from July 2012 to July 2017 (N = 411).MethodsWe examined factors associated with time from first PrEP discussion with a provider to PrEP initiation date using an adjusted Cox proportional-hazards model, with hazard ratios (HRs) >1 indicating earlier initiation. We also examined the relationship between delayed PrEP initiation and PrEP persistence (staying on PrEP) in an adjusted Cox proportional-hazards model.ResultsPrEP users initiated PrEP after a median of only 7 days. However, there were notable outliers, with 29% waiting >30 days and 12% waiting >90 days. In an adjusted proportional-hazards model, a panel management and patient navigation intervention was associated with earlier PrEP initiation [HR: 1.5; 95% confidence interval (CI): 1.1 to 2.0], whereas only other race/ethnicity compared with white race was associated with delayed PrEP initiation (HR: 0.7; 95% CI: 0.5 to 1.0). Delayed PrEP initiation >30 days was associated with shorter PrEP persistence in an adjusted proportional-hazards model (HR: 1.3; 95% CI: 1.0 to 1.7).ConclusionsPrEP initiation within a week is feasible in a primary care safety-net health system. Setting a goal of rapid PrEP initiation, with the support of panel management and patient navigation, could address delays in at-risk groups
From Heisenberg matrix mechanics to EBK quantization: theory and first applications
Despite the seminal connection between classical multiply-periodic motion and
Heisenberg matrix mechanics and the massive amount of work done on the
associated problem of semiclassical (EBK) quantization of bound states, we show
that there are, nevertheless, a number of previously unexploited aspects of
this relationship that bear on the quantum-classical correspondence. In
particular, we emphasize a quantum variational principle that implies the
classical variational principle for invariant tori. We also expose the more
indirect connection between commutation relations and quantization of action
variables. With the help of several standard models with one or two degrees of
freedom, we then illustrate how the methods of Heisenberg matrix mechanics
described in this paper may be used to obtain quantum solutions with a modest
increase in effort compared to semiclassical calculations. We also describe and
apply a method for obtaining leading quantum corrections to EBK results.
Finally, we suggest several new or modified applications of EBK quantization.Comment: 37 pages including 3 poscript figures, submitted to Phys. Rev.
Mercury Exposure and Antinuclear Antibodies among Females of Reproductive Age in the United States: NHANES
Background: Immune dysregulation associated with mercury has been suggested, though data in the general population are lacking. Chronic exposure to low levels of methylmercury (organic) and inorganic mercury is common, such as through fish consumption and dental amalgams.
Objective: To examine associations between mercury biomarkers and antinuclear antibody (ANA) positivity and titer strength.
Methods: Among females 16-49 years (n=1352) from the National Health and Nutrition Examination Survey (NHANES) 1999-2004, we examined cross-sectional associations between mercury and ANAs (indirect immunofluorescence; cutoff ≥1:80). Three biomarkers of mercury exposure were utilized: hair (available 1999-2000) and total blood (1999-2004) predominantly represented methylmercury, and urinary (1999-2002) inorganic. Survey statistics were used. Multivariable modeling adjusted for several covariates, including age and omega-3 fatty acids.
Results: 16% of females were ANA-positive; 96% of ANA-positives had a nuclear staining pattern of speckled. Mercury geometric means (standard deviations) were: 0.22 (0.03) ppm hair, 0.92 (0.05) µg/L blood, and 0.62 (0.04) µg/L urinary. Hair and blood, but not urinary, mercury were associated with ANA positivity (sample sizes 452, 1352, and 804, respectively), adjusting for confounders: hair odds ratio (OR)=4.10 (95% CI: 1.66, 10.13); blood OR=2.32 (95% CI: 1.07, 5.03) comparing highest versus lowest quantiles. Magnitudes of association were strongest for high-titer (≥1:1280) ANA: hair OR=11.41 (95% CI: 1.60, 81.23); blood OR=5.93 (95% CI: 1.57, 22.47).
Conclusions: Methylmercury, at low levels generally considered safe, was associated with subclinical autoimmunity among reproductive-age females. Autoantibodies may predate clinical disease by years, thus methylmercury exposure may be relevant to future autoimmune disease risk.This work was supported by NIH/NIEHS K01ES019909, NIH/NIEHS
P30ES017885, and NIH/NCRR UL1RR024986. ECS was supported in part by an Arthritis Foundation Health Professional New Investigator Award.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110512/1/SOMERS_EHP.AdvancePubl 02102015.acco.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/110512/2/Somers_EHP Suppl-1408751.s001.508.pdf114Description of SOMERS_EHP.AdvancePubl 02102015.acco.pdf : Main ArticleDescription of Somers_EHP Suppl-1408751.s001.508.pdf : Supplementary Materia
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