8,442 research outputs found

    The Astrophysical Uncertainties Of Dark Matter Direct Detection Experiments

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    The effects of astrophysical uncertainties on the exclusion limits at dark matter direct detection experiments are investigated for three scenarios: elastic, momentum dependent and inelastically scattering dark matter. We find that varying the dark matter galactic escape velocity and the Sun's circular velocity can lead to significant variations in the exclusion limits for light (10\lesssim10 GeV) elastic and inelastic scattering dark matter. We also calculate the limits using one hundred velocity distributions extracted from the Via Lactea II and GHALO N-body simulations and find that a Maxwell-Boltzmann distribution with the same astrophysical parameters generally sets less constraining limits. The elastic and momentum dependent limits remain robust for masses 50\gtrsim50 GeV under variations of the astrophysical parameters and the form of the velocity distribution.Comment: 14 pages, 7 figures; v2 final corrected version to appear in Physical Review D; v3 corrected a typo in Eqn. (B4

    Alumina-supported Pd-Ag catalysts for low-temperature CO and methanol oxidation

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    Pd-Ag bimetallic catalysts, supported on gamma-Al2O3, have been evaluated as exhaust catalysts for methanol-fueled vehicles. Laboratory studies have shown that a 0.01% Pd-5% Ag catalyst has greater CO and CH3OH oxidation activity than either 0.01% Pd or 5% Ag catalysts alone. Moreover, Pd and Ag interact synergistically in the bimetallic catalyst to produce greater CO and CH3OH oxidation rates and lower yields of methanol partial oxidation products than expected from a mixture of the single-component catalysts. The Pd-Ag synergism results from Pd promoting the rate of O2 adsorption and reaction with CO and CH3OH on Ag. Rate enhancement by the bimetallic catalyst is greatest at short reactor residence times where the oxygen adsorption rate limits the overall reaction rate

    A new scale to assess the therapeutic relationship in community mental health care: STAR

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    Background. No instrument has been developed specifically for assessing the clinician-patient therapeutic relationship (TR) in community psychiatry. This study aimed to develop a measure of the TR with clinician and patient versions using psychometric principles for test construction. Method. A four-stage prospective study was undertaken, comprising qualitative semi-structured interviews about TRs with clinicians and patients and their assessment of nine established scales for their applicability to community care, administering an amalgamated scale of more than 100 items, followed by Principal Components Analysis (PCA) of these ratings for preliminary scale construction. test-retest reliability of the scale and administering the scale in a new sample to confirm its factorial structure. The sample consisted of patients with severe mental illness and a designated key worker in the care of 17 community mental health teams in England and Sweden. Results. New items not covered by established scales were identified, including clinician helpfulness in accessing services, patient aggression and family interference. The new patient (STAR-P) and clinician scales (STAR-C) each have 12 items comprising three subscales: positive collaboration and positive clinician input in both versions, non-supportive clinician input in the patient version, and emotional difficulties in the clinician version. Test-retest reliability was r = 0(.)76 for STAR-P and r = 0(.)68 for STAR-C. The factorial structure of the new scale was confirmed with a good fit. Conclusions. STAR is a specifically developed, brief scale to assess TRs in community psychiatry with good psychometric properties and is suitable for use in research and routine care
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