Acceptability, feasibility and impact of routine screening to detect undiagnosed HIV infection in 17 - 24-month-old children in the western sub-district of Cape Town

Objectives. To explore the acceptability and feasibility of routine HIV screening in children at primary healthcare clinics and ascertain the prevalence of previously undiagnosed HIV infection in 17 - 24-month-old children accessing curative and routine services.Methods. A survey was conducted in 4 primary health clinics in the western sub-district of Cape Town. Rapid HIV screening of 17 - 24-monthold children was performed for consenting caregiver-child pairs. Data on demographics, child health and antenatal history were collected using questionnaires.Results. During recruitment, 358 children (72%) were tested for HIV infection. Most of the children (95.8%) were accompanied by a parent. The prevalence of reported HIV exposure among children was 21% (107/499). Of these, 3 had previously confirmed HIV infection; 1 was reportedly confirmed by a 6-week HIV test, and the other 2 probably contracted the virus via late postpartum transmission. The overall transmission rate was 3.5% (3/86) and the confirmed proportion of HIV-infected children was 0.8% (3/361). No previously unknown HIV infection was detected.Conclusions. Programmes to prevent mother-to-child transmission are effective, but at-risk infants who test negative at 6 weeks should be monitored for subsequent seroconversion. Parents of HIV-exposed infants are more likely to permit (re)testing of their infants than those whose offspring are not at risk. Routine HIV testing of children is feasible and acceptable at primary level, but may require additional resources to achieve universal coverage. Routine screening at an earlier age may detect previously undiagnosed HIV infection

Combinatorial Bounds and Characterizations of Splitting Authentication Codes

We present several generalizations of results for splitting authentication codes by studying the aspect of multi-fold security. As the two primary results, we prove a combinatorial lower bound on the number of encoding rules and a combinatorial characterization of optimal splitting authentication codes that are multi-fold secure against spoofing attacks. The characterization is based on a new type of combinatorial designs, which we introduce and for which basic necessary conditions are given regarding their existence.Comment: 13 pages; to appear in "Cryptography and Communications

The history of stellar metallicity in a simulated disc galaxy

We explore the chemical distribution of stars in a simulated galaxy. Using simulations of the same initial conditions but with two different feedback schemes (McMaster Unbiased Galaxy Simulations – MUGS – and Making Galaxies in a Cosmological Context – MaGICC), we examine the features of the age–metallicity relation (AMR), and the three-dimensional age– [Fe/H]–[O/Fe] distribution, both for the galaxy as a whole and decomposed into disc, bulge, halo and satellites. The MUGS simulation, which uses traditional supernova feedback, is replete with chemical substructure. This substructure is absent from the MaGICC simulation, which includes early feedback from stellar winds, a modified initial mass function and more efficient feedback. The reduced amount of substructure is due to the almost complete lack of satellites in MaGICC. We identify a significant separation between the bulge and disc AMRs, where the bulge is considerably more metal-rich with a smaller spread in metallicity at any given time than the disc. Our results suggest, however, that identifying the substructure in observations will require exquisite age resolution, of the order of 0.25 Gyr. Certain satellites show exotic features in the AMR, even forming a ‘sawtooth’ shape of increasing metallicity followed by sharp declines which correspond to pericentric passages. This fact, along with the large spread in stellar age at a given metallicity, compromises the use of metallicity as an age indicator, although alpha abundance provides a more robust clock at early times. This may also impact algorithms that are used to reconstruct star formation histories from resolved stellar populations, which frequently assume a monotonically increasing AMR

Violence-related Police Crime Arrests in the United States, 2005-2011

This study is a quantitative content analysis of news reports and court records on 3,328 violence-related arrest cases of 2,586 individual sworn law enforcement officers during the years 2005-2011. The arrested officers were employed by 1,445 nonfederal state, local, special, constable, tribal, and regional law enforcement agencies located in 805 counties and independent cities in 49 states and the District of Columbia. Binary logistic regression and classification and regression tree (CART) analyses were conducted to predict criminal conviction in violence-related police crime arrest cases. Finding indicate that conviction of police officers on one or more offenses charged are driven by specific legal and extralegal factors. Policy implications will be discussed

Polarimetry of transneptunian objects (136472) Makemake and (90482) Orcus

Context. We study the surface properties of transneptunian populations of Solar-system bodies. Aims. We investigate the surface characteristics of the dwarf planet (136472) Makemake and the resonant object (90482) Orcus. Methods. Using the FORS2 instrument of the ESO-VLT we have carried out linear polarisation measurements of Makemake and Orcus. Results. Polarisation of Orcus is similar to that of smaller size objects. The polarimetric properties of Makemake are very close to those of Eris and Pluto. We have not found any significant differences in the polarisation properties of objects from different dynamical classes. However, there are significant differences in polarisation of large and smaller size objects, and between large TNOs with water-ice and methane-ice dominated surfaces. Conclusions. We confirm the different types of polarisation phase behavior for the largest and smaller size TNOs. To explain subtle surface polarisation of Pluto, Makemake and Eris we assume that their surfaces are covered by a thin layer of hoarfrost masking the surface structure

Plant invasion impacts on fungal community structure and function depends on soil warming and nitrogen enrichment

The impacts of invasive species on biodiversity may be mitigated or exacerbated by abiotic environmental changes. Invasive plants can restructure soil fungal communities with important implications for native biodiversity and nutrient cycling, yet fungal responses to invasion may depend on numerous anthropogenic stressors. In this study, we experimentally invaded a long-term soil warming and simulated nitrogen deposition experiment with the widespread invasive plant Alliaria petiolata (garlic mustard) and tested the responses of soil fungal communities to invasion, abiotic factors, and their interaction. We focused on the phytotoxic garlic mustard because it suppresses native mycorrhizae across forests of North America. We found that invasion in combination with warming, but not under ambient conditions or elevated nitrogen, significantly reduced soil fungal biomass and ectomycorrhizal relative abundances and increased relative abundances of general soil saprotrophs and fungal genes encoding for hydrolytic enzymes. These results suggest that warming potentially exacerbates fungal responses to plant invasion. Soils collected from uninvaded and invaded plots across eight forests spanning a 4 °C temperature gradient further demonstrated that the magnitude of fungal responses to invasion was positively correlated with mean annual temperature. Our study is one of the first empirical tests to show that the impacts of invasion on fungal communities depends on additional anthropogenic pressures and were greater in concert with warming than under elevated nitrogen or ambient conditions

California Police Sexual Misconduct Arrest Cases, 2005-2011

This report was prepared at the request of the California Research Bureau. The data are from a larger study on police crime in the United States. Police crimes are those crimes committed by sworn law enforcement officers given the general powers of arrest at the time the offense was committed and/or at the time when the officer was arrested. These crimes can occur while the officer is on- or off-duty and include offenses committed by state, county, municipal, tribal, or special law enforcement agencies. Police crimes damage the occupational integrity of police officers, the organizational legitimacy of the employing law enforcement agency, and the overall authority and legitimacy of the law enforcement community. According to Stinson’s (2009) typology of police crime, nearly all crime committed by sworn law enforcement officers is alcohol-related, drug-related, sex-related, violence-related, and/or profit-motivated. This report focuses on the sex-related police crime arrests of sworn law enforcement officers in the State of California during the years 2005-2011

Breathing in Low Mass Galaxies: A Study of Episodic Star Formation

We simulate the collapse of isolated dwarf galaxies using SPH + N-Body simulations including a physically motivated description of the effects of supernova feedback. As the gas collapses and stars form, the supernova feedback disrupts enough gas to temporarily quench star formation. The gas flows outward into a hot halo, where it cools until star formation can continue once more and the cycle repeats. The star formation histories of isolated Local Group dwarf galaxies exhibit similar episodic bursts of star formation. We examine the mass dependence of the stellar velocity dispersions and find that they are no less than half the velocity of the halos measured at the virial radius.Comment: 5 pages, 3 figures, accepted ApJ. Full resolution figures and movies available at http://hpcc.astro.washington.edu/feedbac

The stellar metallicity distribution of disc galaxies and bulges in cosmological simulations

By means of high-resolution cosmological hydrodynamical simulations of Milky Way-like disc galaxies, we conduct an analysis of the associated stellar metallicity distribution functions (MDFs). After undertaking a kinematic decomposition of each simulation into spheroid and disc sub-components, we compare the predicted MDFs to those observed in the solar neighbourhood and the Galactic bulge. The effects of the star formation density threshold are visible in the star formation histories, which show a modulation in their behaviour driven by the threshold. The derived MDFs show median metallicities lower by 0.2-0.3 dex than the MDF observed locally in the disc and in the Galactic bulge. Possible reasons for this apparent discrepancy include the use of low stellar yields and/or centrally-concentrated star formation. The dispersions are larger than the one of the observed MDF; this could be due to simulated discs being kinematically hotter relative to the Milky Way. The fraction of low metallicity stars is largely overestimated, visible from the more negatively skewed MDF with respect to the observational sample. For our fiducial Milky Way analog, we study the metallicity distribution of the stars born "in situ" relative to those formed via accretion (from disrupted satellites), and demonstrate that this low-metallicity tail to the MDF is populated primarily by accreted stars. Enhanced supernova and stellar radiation energy feedback to the surrounding interstellar media of these pre-disrupted satellites is suggested as an important regulator of the MDF skewness.Comment: 20 pages, 14 figures, MNRAS, accepte

Clinician compliance with laboratory monitoring and prescribing guidelines in HIV 1-infected patients receiving tenofovir

Background. Tenofovir is part of the preferred first-line regimen for HIV-infected patients in South Africa (SA), but is associated with kidney toxicity. SA antiretroviral therapy (ART) guidelines recommend creatinine monitoring at baseline (ART start) and at 3, 6 and 12 months, and substituting tenofovir with zidovudine, stavudine or abacavir should creatinine clearance (CrCl) decrease to <50 mL/min.Objective. To assess clinician compliance with tenofovir monitoring and prescribing guidelines.Methods. We described the proportion of adult patients on tenofovir-based first-line ART who were screened for baseline renal impairment, were monitored according to the SA antiretroviral treatment guidelines, and were switched from tenofovir if renal function declined.Results. We included 13 168 patients who started ART from 2010 to 2012. Creatinine concentrations were recorded in 11 712 (88.9%) patients on tenofovir at baseline, 9 135/11 657 (78.4%) at 3 months, 5 426/10 554 (51.4%) at 6 months, and 5 949/ 8 421 (70.6%) at 12 months. At baseline, 227 (1.9%) started tenofovir despite a CrCl <50 mL/min. While on tenofovir, 525 patients had at least one CrCl of <50 mL/min. Of 382 patients with ≥3 months’ follow-up after a CrCl <50 mL/min, 114 (29.8%) stopped tenofovir within 3 months. Clinicians were more likely to stop tenofovir in patients with lower CrCl and CD4 count. Of 226 patients who continued to receive tenofovir and had further CrCls available, 156 (69.0%) had a CrCl ≥50 mL/min at their next visit.Conclusions. Creatinine monitoring is feasible where access to laboratory services is good. Kidney function recovered in most patients who continued to receive tenofovir despite a CrCl <50 mL/min. Further research is needed to determine how best to monitor renal function with tenofovir in resource-limited settings