Increase of Black Hole Entropy in Higher Curvature Gravity

We examine the Zeroth Law and the Second Law of black hole thermodynamics within the context of effective gravitational actions including higher curvature interactions. We show that entropy can never decrease for quasi-stationary processes in which a black hole accretes positive energy matter, independent of the details of the gravitational action. Within a class of higher curvature theories where the Lagrangian consists of a polynomial in the Ricci scalar, we use a conformally equivalent theory to establish that stationary black hole solutions with a Killing horizon satisfy the Zeroth Law, and that the Second Law holds in general for any dynamical process. We also introduce a new method for establishing the Second Law based on a generalization of the area theorem, which may prove useful for a wider class of Lagrangians. Finally, we show how one can infer the form of the black hole entropy, at least for the Ricci polynomial theories, by integrating the changes of mass and angular momentum in a quasistationary accretion process.Comment: 20 pages, LaTe

Entropy of Lovelock Black Holes

A general formula for the entropy of stationary black holes in Lovelock gravity theories is obtained by integrating the first law of black hole mechanics, which is derived by Hamiltonian methods. The entropy is not simply one quarter of the surface area of the horizon, but also includes a sum of intrinsic curvature invariants integrated over a cross section of the horizon.Comment: 15 pages, plain Latex, NSF-ITP-93-4

Lorentz violation at high energy: concepts, phenomena and astrophysical constraints

We consider here the possibility of quantum gravity induced violation of Lorentz symmetry (LV). Even if suppressed by the inverse Planck mass such LV can be tested by current experiments and astrophysical observations. We review the effective field theory approach to describing LV, the issue of naturalness, and many phenomena characteristic of LV. We discuss some of the current observational bounds on LV, focusing mostly on those from high energy astrophysics in the QED sector at order E/M_Planck. In this context we present a number of new results which include the explicit computation of rates of the most relevant LV processes, the derivation of a new photon decay constraint, and modification of previous constraints taking proper account of the helicity dependence of the LV parameters implied by effective field theory.Comment: v.1 56 pages, 3 figures, Invited article for Annals of Physics; v.2: 60 pages, 3 figures. Typos fixed, references added, minor editing for clarity and accuracy; discussion of fermion pair emission added. To appear in January 2006 special issue of Annals of Physic

Impact evaluation of a community-based intervention to reduce risky sexual behaviour among female sex workers in Shanghai, China.

BACKGROUND: Female sex workers (FSWs) are at risk for sexually transmitted infections (STIs), including HIV. We implemented an HIV/STI preventive intervention among FSWs in Shanghai that aimed to increase condom use, improve HIV knowledge, and reduce STI and HIV incidence. METHODS: From six districts in Shanghai, 750 randomly selected venue-based FSWs were allocated to either a behavioural intervention or control group. In the intervention and control groups, 221 and 278 participants, respectively, had at least one follow-up at three or six months. In analysis, we randomly selected 57 lost to follow-up cases in the intervention group and imputed baseline values to equalize the arms at n = 278 (74.1% follow-up rate in each group). The impacts of the intervention on condom use, HIV/STI risk perception and knowledge, and STI incidence were assessed using either a logistic or linear model, adjusting for the baseline measure of the outcome and venue type. RESULTS: The intervention improved consistent condom use with any partner type in the previous month (AOR = 2.09, 95% CI, 1.43-3.04, p = 0.0001). Consistent condom use with clients in the three most recent sex acts increased in both arms, and with primary partners in the intervention arm, but there was no difference between groups after adjusting for baseline condom use and venue type. There were no differences in cumulative incidence of any STI (i.e., chlamydia, gonorrhoea, syphilis) between groups. HIV transmission knowledge (p = 0.0001), condom use skill (p = 0.0421), and self-efficacy for using condoms (p = 0.0071) were improved by the intervention. HIV-related stigma declined (p = 0.0119) and HIV and STI risk perception were improved (4.6 to 13.9%, and 9.4 to 20.0%, respectively). The intervention was associated with these improvements after adjusting for the baseline measure and venue type. CONCLUSION: Following a preventive intervention among Shanghai FSWs, our findings demonstrate that a simple, community-based educational intervention improved overall condom use, HIV and STI knowledge, and attitudes in relation to HIV/AIDS. The intervention should be implemented widely after tailoring educational materials regarding condom negotiation with different partner types (i.e., commercial sex clients and primary partners)

HIV testing experiences of Aboriginal youth in Canada: service implications

The objective of this study was to explore HIV testing experiences and service views of Canadian Aboriginal youth in order to provide information for HIV testing services. An exploratory, mixed-method, community-based research design was used for this study. Findings reported here are from 210 survey participants who had experienced an HIV test. Youth were recruited through 11 Aboriginal organizations across Canada, including AIDS service organizations, health centers, community organizations, and friendship centers. Youth who had tested for HIV ranged in age from 15 to 30 years of age (20% were B20), and came from First Nations (75%), Me ́ tis (14%), and Inuit (9%) backgrounds. Participants lived in all provinces and one territory. Over half (62%) were female. While the majority of survey respondents indicated at their last HIV test they had been treated with care (80%), respect (77%), or kindness (76%), some reported being treated with hostility (19%), fear (12%), discrimination (11%), avoidance (10%), or being treated in a bored way (15%). When asked about information they had received, 28% of survey respondents could not remember; 23% said they were not given any information, and 24% said their questions were not answered. Emotional reactions to testing ranged from anxiety/apprehension (64% of survey respondents) to being ‘‘calm’’ (19%). When asked for suggestions to improve testing services, participants indicated emotional support, compassion, professional yet personable services, and personalized HIV information were important. Study results suggest that to facilitate HIV testing for Aboriginal youth, testing services and counseling must be respectful, compassionate, non-judgmental, and culturally responsive in order to provide emotional support and HIV information that is meaningful and memorable

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected

HIV and Rehabilitation Training Needs of Health Professionals in Canada: Results of a National Survey

Background: People with HIV experience a range of health-related challenges that rehabilitation services are well-positioned to address. The purpose of this study was to explore professional knowledge and views about HIV rehabilitation among HIV specialists and rehabilitation professionals in Canada.Methods and Findings: We conducted a nationwide cross-sectional postal survey with a random sample of rehabilitation professionals (physical therapists, occupational therapists, speech-language pathologists, and physiatrists) (N = 1058) and the known population of HIV specialists (physicians, nurses, social workers, pharmacists, psychologists, and dietitians) in Canada (N = 214). Two-thirds (67%) of rehabilitation professionals disagreed that rehabilitation professionals possess adequate knowledge and skills to assess and treat people living with HIV. The majority of all respondent groups felt that rehabilitation professionals who work with people living with HIV require specialized HIV training. Approximately one-third (32%) of rehabilitation professionals who had served people living with HIV stated they received some HIV training as part of their professional degree.Conclusions: This was the first national survey to explore HIV specialist and rehabilitation professionals’ knowledge and views about HIV rehabilitation. Findings indicate the need for interprofessional education, training, and mentorship of health professionals to address the gap between the needs of people living with HIV and rehabilitation services provision