182 research outputs found

    Modelling and observation of transionospheric propagation results from ISIS II in preparation for ePOP

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    The enhanced Polar Outflow Probe (ePOP) is scheduled to be launched as part of the Cascade Demonstrator Small-Sat and Ionospheric Polar Explorer (CASSIOPE) satellite in early 2008. A Radio Receiver Instrument (RRI) on ePOP will receive HF transmissions from various ground-based transmitters. In preparation for the ePOP mission, data from a similar transionospheric experiment performed by the International Satellites for Ionospheric Studies (ISIS) II satellite has been studied. Prominent features in the received 9.303-MHz signal were periodic Faraday fading of signal intensity at rates up to 13 Hz and a time of arrival delay between the O- and X-modes of up to 0.8 ms. Both features occurred when the satellite was above or south of the Ottawa transmitter. Ionospheric models for ray tracing were constructed using both International Reference Ionosphere (IRI) profiles and local peak electron density values from ISIS ionograms. Values for fade rate and differential mode delay were computed and compared to the values observed in the ISIS II data. The computed values showed very good agreement to the observed values of both received signal parameters when the topside sounding <I>fo</I>F2 values were used to scale IRI profiles, but not when strictly modelled IRI profiles were used. It was determined that the primary modifier of the received signal parameters was the <I>fo</I>F2 density and not the shape of the profile. This dependence was due to refraction, at the 9.303-MHz signal frequency, causing the rays to travel larger distances near the peak density where essentially all the mode splitting occurred. This study should assist in interpretation of ePOP RRI data when they are available

    Assessment of Clinical Partner Violence Screening Tools

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    Objective: to compare the Women’s Experience with Battering Scale (WEB) with the Index of Spouse Abuse-Physical Scale (ISA-P) as screening tools to identify intimate partner violence (IPV). Methods: We conducted a large cross-sectional survey of women age 18 to 65 attending one of two family practice clinics from 1997 to 1998. All women completed both the WEB and the ISA-P and a telephone interview. We figured agreement estimates between the two tools, used stratified analyses to evaluate attributes of those more likely to screen as battered or physically assaulted, and compared associations between the WEB and ISA-P and a range of mental and physical health indicators known to be associated with IPV. Results: 18% of 1152 eligible women surveyed had experienced IPV in a current or most recent intimate rela-tionship with a male partner; 17% had been battered (WEB+), and 10% had been physically assaulted (ISA-P+). Had we used the ISA-P alone to assess IPV, we would have missed almost 45% of IPV. As anticipated, the ISA-P was more strongly associated with IPV-associated injuries and number of physician visits in the last year. The WEB was more strongly associated with self-perceived mental health, anxiety, depression, drug abuse, and low social support. Conclusion: Clinicians need validated screening tools to rapidly and reliably screen patients for IPV. Most screening tools assess physical violence and injury without considering the more chronic experience of battering and the psychological terror associated with this violence. The WEB may identify more abused women than tools measuring physical assaults

    The Relationship Between Diet, Activity, and Other Factors, and Postpartum Weight Change by Race

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    Objective: To identify the impact of dietary intake and activity level on postpartum weight change. Methods: White (n = 121) and black (n = 224) women, 7-12 months postpartum, participating in the Special Supplemental Feeding Program for Women, Infants, and Children were assessed for dietary intake, activity level, body weight, and other maternal characteristics. Results: For both black and white women, the most important variables in predicting postpartum weight loss were pre-pregnancy weight, gestational weight gain, parity, and prenatal exercise. After these factors were controlled, race predicted that black women retained 6.4 lb more than white women. These results may be due to the finding that black women reported significantly higher mean energy intake (2039 versus 1552 kcal, P \u3c .001), higher percent fat in diet (41 versus 38%, P \u3c .001), and significantly lower amounts of prenatal and postpartum activity. Conclusion: Higher energy intake and lower activity levels in black postpartum mothers compared with white mothers may contribute to the significantly higher rates of obesity found in black mothers. This study suggests the need for intervention strategies in the prenatal and postpartum periods to help those at risk of retaining weight gained during pregnancy

    Soil zinc content, groundwater usage, and prostate cancer incidence in South Carolina

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    Background Prostate cancer (PrCA) incidence in South Carolina (SC) exceeds the national average, particularly among African Americans (AAs). Though data are limited, low environmental zinc exposures and down-regulation of prostatic zinc transporter proteins among AAs may explain, in part, the racial PrCA disparity. Methods Age-adjusted PrCA rates were calculated by census tract. Demographic data were obtained from the 1990 census. Hazardous waste site locations and soil zinc concentrations were obtained from existing federal and state databases. A geographic information system and Poisson regression were used to test the hypothesis that census tracts with reduced soil zinc concentrations, elevated groundwater use, or more agricultural or hazardous waste sites had elevated PrCA risks. Results Census tracts with high groundwater use and low zinc concentrations had higher PrCA rate ratios (RR: 1.270; 95% confidence interval: 1.079, 1.505). This effect was not more apparent in areas populated primarily by AAs. Conclusion Increased PrCA rates were associated with reduced soil zinc concentrations and elevated groundwater use, although this observation is not likely to contribute to SC’s racial PrCA disparity. Statewide mapping and statistical modeling of relationships between environmental factors, demographics, and cancer incidence can be used to screen hypotheses focusing on novel PrCA risk factors

    Provider Behavior Under Global Budgeting and Policy Responses: An Observational Study on Eye Care Services in Taiwan

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    Third-party payer systems are consistently associated with health care cost escalation. Taiwan’s single-payer, universal coverage National Health Insurance (NHI) adopted global budgeting (GB) to achieve cost control. This study captures ophthalmologists’ response to GB, specifically service volume changes and service substitution between low-revenue and high-revenue services following GB implementation, the subsequent Bureau of NHI policy response, and the policy impact. De-identified eye clinic claims data for the years 2000, 2005, and 2007 were analyzed to study the changes in Simple Claim Form (SCF) claims versus Special Case Claims (SCCs). The 3 study years represent the pre-GB period, post-GB but prior to region-wise service cap implementation period, and the post-service cap period, respectively. Repeated measures multilevel regression analysis was used to study the changes adjusting for clinic characteristics and competition within each health care market. SCF service volume (low-revenue, fixed-price patient visits) remained constant throughout the study period, but SCCs (covering services involving variable provider effort and resource use with flexibility for discretionary billing) increased in 2005 with no further change in 2007. The latter is attributable to a 30% cap negotiated by the NHI Bureau with the ophthalmology association and enforced by the association. This study demonstrates that GB deployed with ongoing monitoring and timely policy responses that are designed in collaboration with professional stakeholders can contain costs in a health insurance–financed health care system

    Characterisation of extracellular redox enzyme concentrations in response to exercise in humans.

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    Redox enzymes are ubiquitous proteins that modulate intracellular redox balance and can be secreted in response to cellular oxidative stress, potentially modulating systemic inflammation. Both aerobic and resistance exercise are known to cause acute systemic oxidative stress and inflammation; however, how redox enzyme concentrations alter in extracellular fluids following bouts of either type of exercise is unknown. Recreationally active males (n=26, age 28 ± 8 years) took part in either: 1) two separate energy-matched cycling bouts: one of moderate intensity (MOD) and a bout of high intensity interval exercise (HIIE) or 2) a resistance exercise protocol. Alterations in plasma (study 1) and serum (study 2) peroxiredoxin (PRDX)-2, PRDX-4, superoxide dismutase-3 (SOD3), thioredoxin (TRX-1), TRX-reductase and Interleukin (IL)-6 were assessed before and at various timepoints after exercise. There was a significant increase in SOD3 (+1.5 ng/mL) and PRDX-4 (+5.9 ng/mL) concentration following HIIE only, peaking at 30- and 60-min post-exercise respectively. TRX-R decreased immediately and 60-min following HIIE (-7.3 ng/mL) and MOD (-8.6 ng/mL) respectively. In non-resistance trained males, no significant changes in redox enzyme concentrations were observed up to 48 hours following resistance exercise, despite significant muscle damage. IL-6 concentration increased in response to all trials, however there was no significant relationship between absolute or exercise-induced changes in redox enzyme concentrations. These results collectively suggest that HIIE, but not MOD or eccentric exercise increase the extracellular concentration of PRDX-4 and SOD3. Exercise-induced changes in redox enzyme concentration do not appear to directly relate to systemic changes in IL-6 concentration

    Phonon dispersion in 1-layer cuprate HgBa2CuO4+d

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    We investigate the low energy acoustical and optical modes in HgBa2CuO4+δ\mathrm{HgBa_2CuO_{4+\delta}} using inelastic x-ray scattering (IXS). The experimental phonon dispersion and the dynamical structure factor are compared with an atomic shell model, and the set of the atomic potentials obtained are discussed. Our results are also compared with those obtained by Raman spectroscopy and with density-of-state data measured by inelastic neutron scattering
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