1,153 research outputs found
Heavy flavor in heavy-ion collisions at RHIC and RHIC II
In the initial years of operation, experiments at the Relativistic Heavy Ion
Collider (RHIC) have identified a new form of matter formed in nuclei-nuclei
collisions at energy densities more than 100 times that of a cold atomic
nucleus. Measurements and comparison with relativistic hydrodynamic models
indicate that the matter thermalizes in an unexpectedly short time, has an
energy density at least 15 times larger than needed for color deconfinement,
has a temperature about twice the critical temperature predicted by lattice
QCD, and appears to exhibit collective motion with ideal hydrodynamic
properties - a "perfect liquid" that appears to flow with a near-zero viscosity
to entropy ratio - lower than any previously observed fluid and perhaps close
to a universal lower bound. However, a fundamental understanding of the medium
seen in heavy-ion collisions at RHIC does not yet exist. The most important
scientific challenge for the field in the next decade is the quantitative
exploration of the new state of nuclear matter. That will require new data that
will, in turn, require enhanced capabilities of the RHIC detectors and
accelerator. In this report we discuss the scientific opportunities for an
upgraded RHIC facility - RHIC II - in conjunction with improved capabilities of
the two large RHIC detectors, PHENIX and STAR. We focus solely on heavy flavor
probes. Their production rates are calculable using the well-established
techniques of perturbative QCD and their sizable interactions with the hot QCD
medium provide unique and sensitive measurements of its crucial properties
making them one of the key diagnostic tools available to us.Comment: 96 pages, 53 figures. Accepted for publication in Physics Reports.
Fixed typo in Fig. 15 captio
Narrowing the uncertainty on the total charm cross section and its effect on the J/\psi\ cross section
We explore the available parameter space that gives reasonable fits to the
total charm cross section to make a better estimate of its true uncertainty. We
study the effect of the parameter choices on the energy dependence of the
J/\psi\ cross section.Comment: 19 pages, 13 figure
Improving the J/psi Production Baseline at RHIC and the LHC
We assess the theoretical uncertainties on the inclusive J/psi production
cross section in the Color Evaporation Model (CEM) using values for the charm
quark mass, renormalization and factorization scales obtained from a fit to the
charm production data. We use our new results to provide improved baseline
comparison calculations at RHIC and the LHC. We also study cold matter effects
on J/psi production at leading relative to next-to-leading order in the CEM
within this approach.Comment: Proceedings for Hard Probes 2012, Cagliari, Ital
Application of a Multi-Objective Network Model to a Combat Simulation Game: The Drive on Metz Case Study
War games are routinely analyzed by the Department of Defense to study the players decision making process. This research develops a multicriteria model that enhances a war game players decision-making capability. The war game consists of a hexagonal-grid map of varying terrain that will be represent as a two-dimensional directed network. The network is obstructed by multiple enemy threats that expose a unit traversing the network to possible attack. The player is faced with the decision of choosing a route to a target node that balances the objectives of following the shortest path and maximizing the probability of success. A weighted arc cost matrix is supplied to Dijkstras shortest path algorithm to and an optimal route. Critical values of the ratio of the objective function weights determine where the optimal path changes. These values are determined on a test scenario for the war game The Drive On Metz
Improved definition of crustal magnetic anomalies for MAGSAT data
The routine correction of MAGSAT vector magnetometer data for external field effects such as the ring current and the daily variation by filtering long wavelength harmonics from the data is described. Separation of fields due to low altitude sources from those caused by high altitude sources is affected by means of dual harmonic expansions in the solution of Dirichlet's problem. This regression/harmonic filter procedure is applied on an orbit by orbit basis, and initial tests on MAGSAT data from orbit 1176 show reduction in external field residuals by 24.33 nT RMS in the horizontal component, and 10.95 nT RMS in the radial component
The Utilization of Health Services and Self-Care by Older Women With Sleeping Problems: Results From a Nationally Representative Sample of 9,110 Women.
OBJECTIVE: This research aims to investigate the health service use-including complementary and alternative medicine (CAM)-and self-care by women aged 62 to 67 with sleeping problems. METHOD: In total, 9,110 participants (99.6%) responded to questions about sleeping problems, health service utilization and self-care (e.g., herbal medicines and vitamins), demographics, and chronic illnesses. RESULTS: In all, 48.2% ( n = 4,394) women indicated that they had a sleeping problem. Women with sleeping problems consulted a general practitioner (GP) more frequently (odds ratio [OR] = 1.72; 95% confidence interval [CI] = [1.36, 2.17]; p < .005) and were more likely to be using herbal medicines (OR = 1.24; 95% CI = [1.13, 1.36]; p < .005) than women without sleeping problems. DISCUSSION: Health professionals, particularly GPs, may need to actively inquire with older patients in their care with sleeping problems about the use of herbal medicines, to ensure their sleeping problems are being directly and effectively treated, particularly in light of increased risks associated with sleeping problems for this age cohort
The proportion of loss to follow-up from antiretroviral therapy (ART) and its association with age among adolescents living with HIV in sub-Saharan Africa: A systematic review and meta-analysis.
BACKGROUND: Human immunodeficiency virus (HIV) remains a global health threat, especially in developing countries. The successful scale-up of antiretroviral therapy (ART) programs to address this threat is hindered by a high proportion of patient loss to follow-up (LTFU). LTFU is associated with poor viral suppression and increased mortality. It is particularly acute among adolescents, who face unique adherence challenges. Although LTFU is a critical obstacle on the continuum of care for adolescents, few regional-level studies report the proportion of LTFU among adolescents receiving ART. Therefore, a systematic review and meta-analysis were conducted to estimate the pooled LTFU in ART programs among adolescents living with HIV in sub-Saharan Africa (SSA). METHODS: We searched five databases (PubMed, Embase (Elsevier), PsycINFO, CINAHL, and Scopus) for articles published between 2005 and 2020 and reference lists of included articles. The PRISMA guidelines for systematic reviews were followed. A standardised checklist to extract data was used. Descriptive summaries were presented using narrative tables and figures. Heterogeneity within the included studies was examined using the Cochrane Q test statistics and I2 test. Random effect models were used to estimate the pooled prevalence of LTFU among ALHIV. We used Stata version 16 statistical software for our analysis. RESULTS: Twenty-nine eligible studies (n = 285,564) were included. An estimated 15.07% (95% CI: 11.07, 19.07) of ALHIV were LTFU. Older adolescents (15-19 years old) were 43% (AOR = 0.57, 95% CI: 0.37, 0.87) more likely to be LTFU than younger (10-14 years old) adolescents. We find an insignificant relationship between gender and LTFU (AOR = 0.95, 95% CI: 0.87, 1.03). A subgroup analysis found that regional differences in the proportion of adolescent LTFU were not statistically significant. The trend analysis indicates an increasing proportion of adolescent LTFU over time. CONCLUSIONS AND RECOMMENDATIONS: The proportion of LTFU among HIV-positive adolescents in SSA seems higher than those reported in other regions. Older adolescents in the region are at an increased risk for LTFU than younger adolescents. These findings may help policymakers develop appropriate strategies to retain ALHIV in ART services. Such strategies could include community ART distribution points, appointment spacing, adherence clubs, continuous free access to ART, and community-based adherence support
Is there an association between the use of complementary medicine and vaccine uptake: Results of a pilot study
© 2018 The Author(s). Objective: Despite the incredible success of paediatric immunisation, support is not universal. It has been suggested that complementary medicine practitioners enable vaccine rejection and his study aims to explore the relationship between complementary medicine use and paediatric vaccination. A total of 149 Australian parents were recruited via a parenting website and Facebook groups to complete an online questionnaire. Results: The majority of parents (66.4%) stated that their children's vaccination status was up-to-date. Vaccination status was associated with parental education, area of residence, income, private health insurance, and having a Health Care Card (p < 0.05). Children's vaccinations were more likely to be up-to-date if they had consulted a general practitioner in the previous 12 months (OR 21.75; p < 0.001), and less likely to be up-to-date if they had consulted a complementary medicine practitioner (OR 0.10; p < 0.001) in the same period. Concerns about vaccine safety and efficacy were the most common reasons for a child's immunisation status not being up-to-date. These findings highlight an interface between lower vaccine uptake and visits to complementary medicine practitioners. These results emphasise the need to examine the routine paediatric care practices of complementary medicine practitioners as a crucial piece of the puzzle in understanding vaccine rejection
Exploring Sport and Intergroup Relations in Fiji: Guidance for Researchers Undertaking Short-Term Ethnography
There is a key tension associated with ethnographic explorations into the lives of people in the Global South – ‘outsider’ researchers from the Global North who lack experience of the environments they are seeking to understand. A considered response, therefore, is for scholars to seek physical immersion in a field—to live among those they are trying to understand. Such ethnographic inquiries are optimal when researchers have the capacity to engage over long periods of time. However, in some circumstances, this may not feasible. Thus, questions arise about the veracity of field work investigations that are not only temporally brief but undertaken by scholars who lack local experience. This paper reflects on the experiences of a researcher who was faced with those challenges. It provides guidance as to how scholars might prepare for short-term ethnography (STE) in field work, along with the limitations and constraints of such an approach. The research centered on a sport for development and peace study into intergroup relations and ethnic separatism in Fijian sport
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