Long-term X-ray spectral variability in AGN from the Palomar sample observed by Swift

We present X-ray spectral variability of 24 local active galactic nuclei (AGN) from the Palomar sample of nearby galaxies, as observed mainly by Swift. From hardness ratio measurements, we find that 18 AGN with low accretion rates show hardening with increasing count rate, converse to the softer-when-brighter behaviour normally observed in AGN with higher accretion rates. Two AGN show softening with increasing count rate, two show more complex behaviour, and two do not show any simple relationship. Sufficient data were available for the spectra of 13 AGN to be summed in flux-bins. In nine of these sources, correlated luminosity-dependent changes in the photon index (?) of a power-law component are found to be the main cause of hardness variability. For six objects, with a low accretion rate as a fraction of the Eddington rate (m?Edd), ? is anticorrelated with m?Edd, i.e. ‘harder-when-brighter’ behaviour is observed. The three higher m?Edd-rate objects show a positive correlation between ? and m?Edd. This transition from harder-when-brighter at low m?Eddto softer-when-brighter at high m?Edd can be explained by a change in the dominant source of seed-photons for X-ray emission from cyclo-synchrotron emission from the Comptonizing corona itself to thermal seed-photons from the accretion disc. This transition is also seen in the ‘hard state’ of black hole X-ray binaries (BHXRBs). The results support the idea that low-ionization nuclear emission-line regions are analogues of BHXRBs in the hard state and that Seyferts are analogues of BHXRBs in either the high-accretion rate end of the hard state or in the hard-intermediate state

Estimating the cost-effectiveness of detecting cases of chronic hepatitis C infection on reception into prison

Background In England and Wales where less than 1% of the population are Injecting drug users (IDUs), 97% of HCV reports are attributed to injecting drug use. As over 60% of the IDU population will have been imprisoned by the age of 30 years, prison may provide a good location in which to offer HCV screening and treatment. The aim of this work is to examine the cost effectiveness of a number of alternative HCV case-finding strategies on prison reception Methods A decision analysis model embedded in a model of the flow of IDUs through prison was used to estimate the cost effectiveness of a number of alternative case-finding strategies. The model estimates the average cost of identifying a new case of HCV from the perspective of the health care provider and how these estimates may evolve over time. Results The results suggest that administering verbal screening for a past positive HCV test and for ever having engaged in illicit drug use prior to the administering of ELISA and PCR tests can have a significant impact on the cost effectiveness of HCV case-finding strategies on prison reception; the discounted cost in 2017 being £2,102 per new HCV case detected compared to £3,107 when no verbal screening is employed. Conclusion The work here demonstrates the importance of targeting those individuals that have ever engaged in illicit drug use for HCV testing in prisons, these individuals can then be targeted for future intervention measures such as treatment or monitored to prevent future transmission

Effect of time and day of admission on hospital care quality for patients with chronic obstructive pulmonary disease exacerbation in England and Wales: single cohort study

OBJECTIVE: To evaluate if observed increased weekend mortality was associated with poorer quality of care for patients admitted to hospital with chronic obstructive pulmonary disease (COPD) exacerbation. DESIGN: Prospective case ascertainment cohort study. SETTING: 199 acute hospitals in England and Wales, UK. PARTICIPANTS: Consecutive COPD admissions, excluding subsequent readmissions, from 1 February to 30 April 2014 of whom 13 414 cases were entered into the study. MAIN OUTCOMES: Process of care mapped to the National Institute for Health and Care Excellence clinical quality standards, access to specialist respiratory teams and facilities, mortality and length of stay, related to time and day of the week of admission. RESULTS: Mortality was higher for weekend admissions (unadjusted OR 1.20, 95% CI 1.00 to 1.43), and for case-mix adjusted weekend mortality when calculated for admissions Friday morning through to Monday night (adjusted OR 1.19, 95% CI 1.00 to 1.43). Median time to death was 6 days. Some clinical processes were poorer on Mondays and during normal working hours but not weekends or out of hours. Specialist respiratory care was less available and less prompt for Friday and Saturday admissions. Admission to a specialist ward or high dependency unit was less likely on a Saturday or Sunday. CONCLUSIONS: Increased mortality observed in weekend admissions is not easily explained by deficiencies in early clinical guideline care. Further study of out-of-hospital factors, specialty care and deaths later in the admission are required if effective interventions are to be made to reduce variation by day of the week of admission

Crystal Structure of the Sodium Cobaltate Deuterate Superconductor NaxCoO2o4xD2O (x=1/3)

Neutron and x-ray powder diffraction have been used to investigate the crystal structures of a sample of the newly-discovered superconducting sodium cobaltate deuterate compound with composition Na0.31(3)CoO2o1.25(2)D2O and its anhydrous parent compound Na0.61(1)CoO2. The deuterate superconducting compound is formed by coordinating four D2O molecules (two above and two below) to each Na ion in a way that gives Na-O distances nearly equal to those in the parent compound. One deuteron of the D2O molecule is hydrogen bonded to an oxygen atom in the CoO2 plane and the oxygen atom and the second deuteron of each D2O molecule lie approximately in a plane between the Na layer and the CoO2 layers. This coordination of Na by four D2O molecules leads to ordering of the Na ions and D2O molecules. The sample studied here, which has Tc=4.5 K, has a refined composition of Na0.31(3)CoO2o1.25(2)D2O, in agreement with the expected 1:4 ratio of Na to D2O. These results show that the optimal superconducting composition should be viewed as a specific hydrated compound, not a solid solution of Na and D2O (H2O) in NaxCoO2oyD2O. Studies of physical properties vs. Na or D2O composition should be viewed with caution until it is verified that the compound remains in the same phase over the composition range of the study.Comment: 22 pages, 8 figure

Examining the validity and reliability of the Activities-Specific Balance Confidence Scale-6 (ABC-6) in a diverse group of older adults

Losing confidence in the ability to maintain balance can be more debilitating than a fall. Therefore, considering the importance of measuring balance confidence, the purpose of this study was to examine the validity and reliability of the ABC-6, a shortened version of the ABC-16, among diverse older adults. Participants were 251 diverse (72.1% African Americans, 62.5% low-income, 61% low-education) older adults (M age = 71.2 years, SD = 8.9). Participants volunteered for a falls risk screening which assessed multiple falls risk factors and balance confidence. The ABC-6 had excellent internal consistency reliability, substantial intraclass correlations, significant moderate to large correlations with physical activity, mobility, balance, and total falls risk, the ability to discriminate between fallers and nonfallers, and it was the only significant predictor of total falls risk. The ABC-6 was a valid and reliable measure of balance confidence and is a suitable measure for use among diverse older adults

The development of a dispersion modeling casebook for potential hazardous chemical releases

In order to be effective, emergency response actions must be implemented and notifications made almost immediately following a release of hazardous chemicals into the environment. This is particularly true for airborne releases in which dangerous concentrations of a chemical may reach off-site receptors in a matter of minutes. For these releases, preplanning is extremely important. A well-designed dispersion modeling casebook can be a valuable tool for emergency management personnel in these emergencies. This thesis develops a methodology for preparing a dispersion modeling casebook for the potential release of hazardous chemicals. The development of such a casebook consists of several steps including: selecting the chemicals to be considered, obtaining representative meteorological conditions for a facility, determining which airborne chemical concentration levels are going to represent trigger values (values that prompt notification and/or protective action), and performing the dispersion modeling to determine the concentrations that result from several credible chemical release scenarios. The methodology developed in this thesis can be used by any industrial or research facility to prepare a dispersion modeling casebook for airborne hazardous chemical releases. Using the methodology developed in this thesis, a dispersion modeling casebook was prepared for Oak Ridge National Laboratory

Preparation, structural characterisation and antibacterial properties of Ga-doped sol-gel phosphate-based glass

A sol-gel preparation of Ga-doped phosphate-based glass with potential application in antimicrobial devices has been developed. Samples of composition (CaO)(0.30)(Na2O)(0.20-x) (Ga2O3) (x) (P2O5)(0.50) where x = 0 and 0.03 were prepared, and the structure and properties of the gallium-doped sample compared with those of the sample containing no gallium. Analysis of the P-31 MAS NMR data demonstrated that addition of gallium to the sol-gel reaction increases the connectivity of the phosphate network at the expense of hydroxyl groups. This premise is supported by the results of the elemental analysis, which showed that the gallium-free sample contains significantly more hydrogen and by FTIR spectroscopy, which revealed a higher concentration of -OH groups in that sample. Ga K-edge extended X-ray absorption fine structure and X-ray absorption near-edge structure data revealed that the gallium ions are coordinated by six oxygen atoms. In agreement with the X-ray absorption data, the high-energy XRD results also suggest that the Ga3+ ions are octahedrally coordinated with respect to oxygen. Antimicrobial studies demonstrated that the sample containing Ga3+ ions had significant activity against Staphylococcus aureus compared to the control