Curvaton Decay into Baryons, anti-Baryons and Radiation

This paper calculates the amount of baryon/radiation isocurvature fluctuation produced through the decay of a curvaton field. It is shown in particular that if curvaton decay preserves baryon number and the curvaton dominates the energy density at the time of decay, the initial curvaton/radiation isocurvature mode is entirely transfered into a baryon/radiation isocurvature mode. This situation is opposite to that previously studied in three fluid models of curvaton decay; this difference is related to the conservation of the pre-existing baryon asymmetry and to the efficiency of the annihilation of all baryon/anti-baryon pairs produced in the decay. We study in detail the relevant cases in which the curvaton decay preserves or not baryon number and provide analytical and numerical calculations for each situation.Comment: 11 pages, 4 figures, published versio

Reduced auger recombination in mid-infrared semiconductor lasers

A quantum-design approach to reduce the Auger losses in two micron InGaSb type-I quantum well edge-emitting lasers is reported. Experimentally realized structures show a 3X reduction in the threshold, which results in 4.6 lower Auger current loss at room temperature. This is equivalent to a carrier lifetime improvement of 5.7 and represents about a 19-fold reduction in the equivalent “Auger coefficient.

RXTE Spectral Observations of the 1996-97 Outburst of the Microquasar GRO J1655-40

Excellent coverage of the entire 16-month 1996-97 outburst cycle of GRO J1655-40 was provided by RXTE. We present a full spectral analysis of these data, which includes 52 PCA spectra from 2.5-20 keV and HEXTE spectra above 20 keV. We also include a nearly continuous ASM light curve with several intensity measurements per day. The data are interpreted in the context of the multicolor blackbody disk/power-law model. The source is observed in the very high, high/soft, and low/hard outburst states. During the very high state, the source exhibits intense hard flares on time scales of hours to days which are correlated with changes in both the fitted temperature and radius of the inner accretion disk. During the high/soft state, the spectrum is dominated by the soft thermal emission from the accretion disk with spectral parameters that suggest approximately constant inner disk radius and temperature. We find that a tight relationship exists between the observed inner radius of the disk and the flux in the power-law component. During intense hard flares, the inner disk radius is observed to decrease by as much as a factor of three on a time scale of days. The apparent decrease of the inner disk radius observed during the flares may be due to the failure of the multicolor disk model caused by a steepening of the radial temperature profile in the disk coupled with increased spectral hardening and not physical changes of the inner disk radius. Assuming that our spectral model is valid during periods of weak power-law emission, our most likely value for the inner disk radius implies a* < 0.7. Such a low value for the black hole angular momentum is inconsistent with the relativistic frame dragging and the `diskoseismic' models as interpretations for the 300 Hz X-ray QPO seen during some of these RXTE observations.Comment: 34 pages including 9 figures and 3 tables. Accepted for publication in the Astrophysical Journal. Our interpretation of the data and the main conclusions have been significantly revise

Local Government Capacity for Policy Implementation in South Africa: A Study of the Saldanha Bay and Swellendam Municipalities in the Western Cape Province

Philosophiae Doctor - PhDLocal government in South Africa is an autonomous policy implementation arm of the government system. The purpose of this study was to examine the institutional, organisational, and human resource capacity challenges the Saldanha Bay and Swellendam Municipalities in the Western Cape faced in their policy implementation especially on poverty alleviation. The objectives of the study were to develop a theoretical framework for examining institutional, organisational and human resource capacity in the Saldanha Bay and Swellendam Municipalities; to discuss the local government constitutional, legislative and policy framework within which the Saldanha Bay and Swellendam Municipalities delivered services to communities; to examine the capacity challenges in the service delivery of the Saldanha Bay and Swellendam Municipalities and, thereby, highlight operational problem areas; and to make general policy recommendations on the basis of the research findings of the study. The methodology used was the case-study approach. It allowed an in-depth understanding of the dynamics present within Saldanha Bay and Swellendam municipality. The methodology enabled the researcher to answer the research question: In what ways, and with what results has institutional, organisational and human resource capacity affected service delivery in the Saldanha Bay and Swellendam Municipalities in the Western Cape? The major findings of the study were that local government capacity for policy implementation is directly influenced by the presence or otherwise of institutional, organisational and human resource capacity. These dimensions of capacity are mutually inclusive, independent and interrelated in practice. The study makes several policy recommendations. In the area of institutional capacity the recommendations were that floor-crossing legislation and practices must be done away with; that weak capacitated municipalities ought to be alleviated by public - private partnerships as a mechanism to enhance a municipality's ability to develop and implement policy; and that instead of solely setting standards and monitoring performance, the provincial treasury should assist municipalities to acquire financial competencies. In the area of organisational capacity it was recommended that the community ought to participate in the recruitment and selection committee of the Municipal Manager. It was also recommended that municipalities should establish district-wide forums for financial heads whose purpose would be to create a platform for collaboration, and for the exchange of ideas. And in the area of human resource capacity it was recommended that district municipalities ought to assume a more prominent role in building the capacity of the local authorities with which they share legislative and administrative powers. It was also recommended that both the administrative and political leadership ought to participate in compulsory executive and/or leadership training programmes SALGA implements through some tertiary educational institutions and/or through private service providers

Food assistance is associated with improved body mass index, food security and attendance at clinic in an HIV program in central Haiti: a prospective observational cohort study

<p>Abstract</p> <p>Background</p> <p>Few data are available to guide programmatic solutions to the overlapping problems of undernutrition and HIV infection. We evaluated the impact of food assistance on patient outcomes in a comprehensive HIV program in central Haiti in a prospective observational cohort study.</p> <p>Methods</p> <p>Adults with HIV infection were eligible for monthly food rations if they had any one of: tuberculosis, body mass index (BMI) <18.5kg/m², CD4 cell count <350/mm³(in the prior 3 months) or severe socio-economic conditions. A total of 600 individuals (300 eligible and 300 ineligible for food assistance) were interviewed before rations were distributed, at 6 months and at 12 months. Data collected included demographics, BMI and food insecurity score (range 0 - 20).</p> <p>Results</p> <p>At 6- and 12-month time-points, 488 and 340 subjects were eligible for analysis. Multivariable analysis demonstrated that at 6 months, food security significantly improved in those who received food assistance versus who did not (-3.55 vs -0.16; P < 0.0001); BMI decreased significantly less in the food assistance group than in the non-food group (-0.20 vs -0.66; P = 0.020). At 12 months, food assistance was associated with improved food security (-3.49 vs -1.89, P = 0.011) and BMI (0.22 vs -0.67, P = 0.036). Food assistance was associated with improved adherence to monthly clinic visits at both 6 (P < 0.001) and 12 months (P = 0.033).</p> <p>Conclusions</p> <p>Food assistance was associated with improved food security, increased BMI, and improved adherence to clinic visits at 6 and 12 months among people living with HIV in Haiti and should be part of routine care where HIV and food insecurity overlap.</p

Information management to enable personalized medicine: stakeholder roles in building clinical decision support

<p>Abstract</p> <p>Background</p> <p>Advances in technology and the scientific understanding of disease processes are presenting new opportunities to improve health through individualized approaches to patient management referred to as personalized medicine. Future health care strategies that deploy genomic technologies and molecular therapies will bring opportunities to prevent, predict, and pre-empt disease processes but will be dependent on knowledge management capabilities for health care providers that are not currently available. A key cornerstone to the potential application of this knowledge will be effective use of electronic health records. In particular, appropriate clinical use of genomic test results and molecularly-targeted therapies present important challenges in patient management that can be effectively addressed using electronic clinical decision support technologies.</p> <p>Discussion</p> <p>Approaches to shaping future health information needs for personalized medicine were undertaken by a work group of the American Health Information Community. A needs assessment for clinical decision support in electronic health record systems to support personalized medical practices was conducted to guide health future development activities. Further, a suggested action plan was developed for government, researchers and research institutions, developers of electronic information tools (including clinical guidelines, and quality measures), and standards development organizations to meet the needs for personalized approaches to medical practice. In this article, we focus these activities on stakeholder organizations as an operational framework to help identify and coordinate needs and opportunities for clinical decision support tools to enable personalized medicine.</p> <p>Summary</p> <p>This perspective addresses conceptual approaches that can be undertaken to develop and apply clinical decision support in electronic health record systems to achieve personalized medical care. In addition, to represent meaningful benefits to personalized decision-making, a comparison of current and future applications of clinical decision support to enable individualized medical treatment plans is presented. If clinical decision support tools are to impact outcomes in a clear and positive manner, their development and deployment must therefore consider the needs of the providers, including specific practice needs, information workflow, and practice environment.</p