2,292 research outputs found

    The L_X--M relation of Clusters of Galaxies

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    We present a new measurement of the scaling relation between X-ray luminosity and total mass for 17,000 galaxy clusters in the maxBCG cluster sample. Stacking sub-samples within fixed ranges of optical richness, N_200, we measure the mean 0.1-2.4 keV X-ray luminosity, , from the ROSAT All-Sky Survey. The mean mass, , is measured from weak gravitational lensing of SDSS background galaxies (Johnston et al. 2007). For 9 <= N_200 < 200, the data are well fit by a power-law, /10^42 h^-2 erg/s = (12.6+1.4-1.3 (stat) +/- 1.6 (sys)) (/10^14 h^-1 M_sun)^1.65+/-0.13. The slope agrees to within 10% with previous estimates based on X-ray selected catalogs, implying that the covariance in L_X and N_200 at fixed halo mass is not large. The luminosity intercent is 30%, or 2\sigma, lower than determined from the X-ray flux-limited sample of Reiprich & Bohringer (2002), assuming hydrostatic equilibrium. This difference could arise from a combination of Malmquist bias and/or systematic error in hydrostatic mass estimates, both of which are expected. The intercept agrees with that derived by Stanek et al. (2006) using a model for the statistical correspondence between clusters and halos in a WMAP3 cosmology with power spectrum normalization sigma_8 = 0.85. Similar exercises applied to future data sets will allow constraints on the covariance among optical and hot gas properties of clusters at fixed mass.Comment: 5 pages, 1 figure, MNRAS accepte

    Lessons Learned From Inspire Super-Performers

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    Objective: The purpose of this study is to examine what demographic factors correlate with greater rates of upper airway stimulation adherence and efficacy. Study Design: Case control study Introduction: Upper airway stimulation (UAS) is emerging as an effective procedure for select patients with obstructive sleep apnea. As initially studied, this procedure is reserved for those exhibiting body mass index (BMI) Methods: We queried a single surgeonā€™s database of UAS cases, totaling 97 at the time of study. The electronic medical record (EMR) was queried for each patient and pertinent demographics were recorded. We began by defining cohorts: super-adherers were those with greater than 6 hours of nightly device use; non-adherers less than 4. Super-responders had a post-operative AHI and ESS less than 10, and greater than 80% decrease in AHI. Non-responders had an AHI greater than 20 and less than 50% decrease. Super-performers met both super-adherer responder criteria, while non-performers similarly met both negative criteria. Results: Overall, 97 patients underwent hypoglossal nerve stimulation with an average AHI reduction of 67.1%, and 6.2 hours of nightly adherence. 11 patients were defined as super-performers, and 3 as non-performers. 20 patients were super responders vs 11 non-responders. 49 were super adherers vs 34 non-adherers. P-values for various categories will be displayed in Table 1, no difference was found between the groups as age, BMI, sex, pre-op AHI, and pre-op VOTE score were examined. Conclusions: Upper airway stimulation is an effective treatment for patients intolerant of CPAP. In this review there were no statistically significant differences found between the best and lowers performing patients in terms of baseline characteristics

    The social value of a QALY : raising the bar or barring the raise?

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    Background: Since the inception of the National Institute for Health and Clinical Excellence (NICE) in England, there have been questions about the empirical basis for the cost-per-QALY threshold used by NICE and whether QALYs gained by different beneficiaries of health care should be weighted equally. The Social Value of a QALY (SVQ) project, reported in this paper, was commissioned to address these two questions. The results of SVQ were released during a time of considerable debate about the NICE threshold, and authors with differing perspectives have drawn on the SVQ results to support their cases. As these discussions continue, and given the selective use of results by those involved, it is important, therefore, not only to present a summary overview of SVQ, but also for those who conducted the research to contribute to the debate as to its implications for NICE. Discussion: The issue of the threshold was addressed in two ways: first, by combining, via a set of models, the current UK Value of a Prevented Fatality (used in transport policy) with data on fatality age, life expectancy and age-related quality of life; and, second, via a survey designed to test the feasibility of combining respondentsā€™ answers to willingness to pay and health state utility questions to arrive at values of a QALY. Modelling resulted in values of Ā£10,000-Ā£70,000 per QALY. Via survey research, most methods of aggregating the data resulted in values of a QALY of Ā£18,000-Ā£40,000, although others resulted in implausibly high values. An additional survey, addressing the issue of weighting QALYs, used two methods, one indicating that QALYs should not be weighted and the other that greater weight could be given to QALYs gained by some groups. Summary: Although we conducted only a feasibility study and a modelling exercise, neither present compelling evidence for moving the NICE threshold up or down. Some preliminary evidence would indicate it could be moved up for some types of QALY and down for others. While many members of the public appear to be open to the possibility of using somewhat different QALY weights for different groups of beneficiaries, we do not yet have any secure evidence base for introducing such a system

    Ralph B. Stine and Margaret E. Stine v. Henry Girola and Diane Girola and State Underwriters, Inc. : Petition for Rehearing

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    In this paper we present a Remote Control Unit (RCU) that can be attached to any location on a rifle, binoculars, etc., and be operated by a single finger of a soldier without removing his hand from the device. Even for a gloved hand a haptic feedback from the RCU will be realized. A RCU prototype, equipped with a single button, is used as a remote Push-to-Talk (PTT) device for the radio being carried by the soldier. The RCU is powered by the radio waves emitted by this radio. The RCU - being attached to the device - works with a receive unit (RXU) that is attached to and operates the radio. The RCU consists of a RF harvester, energy storage device, a button and a transmitter. Laboratory prototypes are demonstrated

    Responses and relationship dynamics of men and their spouses during active surveillance for prostate cancer: health literacy as an inquiry framework

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    BACKGROUND: Early stage prostate cancer patients may be allocated to active surveillance, where the condition is observed over time with no intervention. Living with a cancer diagnosis may impose stress on both the men and their spouses. In this study we explore whether the scores of and verbal responses to a Health Literacy Questionnaire can be used to identify individuals in need of information and support and to reveal differences in perception and understanding in health related situations within couples. METHODS: We used the nine-domain Health Literacy Questionnaire (HLQ) as a framework to explore health literacy in eight couples where the men were on active surveillance for prostate cancer progression. Scores were calculated for each domain for both individuals. For each couple differences in scores were also calculated and related to the informants\u27 self-reported experiences and reflections in relation to participating in an active surveillance program. Also an inductive analysis was performed to identify themes in the responses and these themes were compared to those of HLQ. RESULTS: The men tended to score higher than their spouses. There was no consistent relation between scores and the reported experiences and reflections. However, some interesting patterns emerged, e.g. in two of the three couples with the largest within couple differences in HLQ scores, responses revealed discrepancies in how the men and their spouses perceived their situation. Also, three themes emerged which related to six of the HLQ domains, i.e. involvement of spouses and other people around the men; support from and interaction with healthcare professionals; and use of the Internet for information retrieval. CONCLUSIONS: Using the HLQ as an interview framework provided insight into the differences within couples and provided new perspectives on their experiences, including their contact with health professionals and the patient-spouse interaction when dealing with prostate cancer. The HLQ used as a dialogue tool may be an adjunct to assist healthcare providers to understand the need for support and information of men with prostate cancer on active surveillance and the dynamics within couples
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