167 research outputs found
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
Financing equitable access to antiretroviral treatment in South Africa
<p>Abstract</p> <p>Background</p> <p>While South Africa spends approximately 7.4% of GDP on healthcare, only 43% of these funds are spent in the public system, which is tasked with the provision of care to the majority of the population including a large proportion of those in need of antiretroviral treatment (ART). South Africa is currently debating the introduction of a National Health Insurance (NHI) system. Because such a universal health system could mean increased public healthcare funding and improved access to human resources, it could improve the sustainability of ART provision. This paper considers the minimum resources that would be required to achieve the proposed universal health system and contrasts these with the costs of scaled up access to ART between 2010 and 2020.</p> <p>Methods</p> <p>The costs of ART and universal coverage (UC) are assessed through multiplying unit costs, utilization and estimates of the population in need during each year of the planning cycle. Costs are from the provider’s perspective reflected in real 2007 prices.</p> <p>Results</p> <p>The annual costs of providing ART increase from US3.6 billion in 2020. If increases in funding to public healthcare only keep pace with projected real GDP growth, then close to 30% of these resources would be required for ART by 2020. However, an increase in the public healthcare resource envelope from 3.2% to 5%-6% of GDP would be sufficient to finance both ART and other services under a universal system (if based on a largely public sector model) and the annual costs of ART would not exceed 15% of the universal health system budget.</p> <p>Conclusions</p> <p>Responding to the HIV-epidemic is one of the many challenges currently facing South Africa. Whether this response becomes a “resource for democracy” or whether it undermines social cohesiveness within poor communities and between rich and poor communities will be partially determined by the steps that are taken during the next ten years. While the introduction of a universal system will be complex, it could generate a health system responsive to the needs of all South Africans.</p
Development and testing of a composite index to monitor the continuum of maternal health service delivery at provincial and district level in South Africa
The continuum of care is a recommended framework for comprehensive health service
delivery for maternal health, and it integrates health system and social determinants of
health. There is a current lack of knowledge on a measurement approach to monitor performance
on the framework. In this study we aim to develop and test a composite index for
assessing the maternal health continuum in a province in South Africa with the possibility of
nationwide use
Children’s representations of nature using photovoice and community mapping: perspectives from South Africa
The aim of the study was to explore children’s representations and perceptions of natural spaces using photovoice and community mapping. The sample consisted of 28 children aged 12–14 years residing in urban and rural communities in the Western Cape, South Africa. Data were collected by means of a series of six focus groups interviews (three photovoice discussion groups and three community mapping discussion groups). For the photovoice missions, children were provided with a 28-exposure disposable camera and given 1 week to complete their missions. Thematic analysis was employed to analyse the data. Three key themes emerged, namely: safe spaces in nature, unsafe spaces in nature, and children’s favourite places in nature. Socio-economic status (SES) was found to be a determining factor in how children make sense of natural spaces. Children from low SES communities indicated being more constricted in their mobility, and were unable to access to safe natural spaces compared to the children from the middle SES community. It is recommended that an expedient starting point would be to work towards and build environmentally and child-friendly communities for children, with children as key contributors in the planning process using a child participation framework.IS
Tracking the international spread of SARS-CoV-2 lineages B.1.1.7 and B.1.351/501Y-V2 with grinch
Late in 2020, two genetically-distinct clusters of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with mutations of biological concern were reported, one in the United Kingdom and one in South Africa. Using a combination of data from routine surveillance, genomic sequencing and international travel we track the international dispersal of lineages B.1.1.7 and B.1.351 (variant 501Y-V2). We account for potential biases in genomic surveillance efforts by including passenger volumes from location of where the lineage was first reported, London and South Africa respectively. Using the software tool grinch (global report investigating novel coronavirus haplotypes), we track the international spread of lineages of concern with automated daily reports, Further, we have built a custom tracking website (cov-lineages.org/global_report.html) which hosts this daily report and will continue to include novel SARS-CoV-2 lineages of concern as they are detected.fals
Monitoring and evaluation of sport-based HIV/AIDS awareness programmes: strengthening outcome indicators
There are number of Non-Governmental Organisations (NGOs) in South Africa that use sport as a tool to respond to Human
Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS), however, little is reported about the outcomes
and impact of these programmes. The aim of this study is to contribute to a generic monitoring and evaluation framework by
improving the options for the use of outcome indicators of sport-based HIV/AIDS awareness programmes of selected NGOs in
South Africa. A qualitative method study was carried out with seven employees of five selected NGOs that integrate sport to
deliver HIV/AIDS programmes in South Africa. The study further involved six specialists/experts involved in the field of HIV/
AIDS and an official from Sport Recreation South Africa (SRSA). Multiple data collection instruments including desktop review,
narrative systematic review, document analysis, one-on-one interviews and focus group interview were used to collect
information on outcomes and indicators for sport-based HIV/AIDS awareness programmes. The information was classified
according to the determinants of HIV/AIDS. The overall findings revealed that the sport-based HIV/AIDS awareness
programmes of five selected NGOs examined in this study focus on similar HIV prevention messages within the key priorities
highlighted in the current National Strategic Plan for HIV/AIDS, STIs and TB of South Africa. However, monitoring and
evaluating outcomes of sport-based HIV/AIDS programmes of the selected NGOs remains a challenge. A need exists for the
improvement of the outcome statements and indicators for their sport-based HIV/AIDS awareness programmes. This study
proposed a total of 51 generic outcome indicators focusing on measuring change in the knowledge of HIV/AIDS and change in
attitude and intention towards HIV risk behaviours. In addition, this study further proposed a total of eight generic outcome
indicators to measure predictors of HIV risk behaviour. The selected NGOs can adapt the proposed generic outcomes and
indicators based on the settings of their programmes. A collaborative approach by all stakeholders is required, from
international organisations, funders, governments, NGOs and communities to strengthening monitoring and evaluation of
sport-based HIV/AIDS awareness programmes including other development programmes. This will assist the NGOs that use
sport for development to be able to reflect accurately the information about their HIV/AIDS activities and also be able to
contribute to on-going monitoring activities at a national and global level as well as to the Sustainable Development Goals.IS
Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic
This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic
Democracy Does Not Cause Growth:The Importance of Endogeneity Arguments
This article challenges recent findings that democracy has sizable effects on economic growth. As extensive political science research indicates that economic turmoil is responsible for causing or facilitating many democratic transitions, the paper focuses on this endogeneity concern. Using a worldwide survey of 165 country-specific democracy experts conducted for this study, the paper separates democratic transitions into those occurring for reasons related to economic turmoil, here called endogenous, and those grounded in reasons more exogenous to economic growth. The behavior of economic growth following these more exogenous democratizations strongly indicates that democracy does not cause growth. Consequently, the common positive association between democracy and economic growth is driven by endogenous democratization episodes (i.e., due to faulty identification)
An Isolated Stellar-Mass Black Hole Detected Through Astrometric Microlensing
We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry of the source star of the long-duration (t_E ~ 270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462, in the direction of the Galactic bulge. HST imaging, conducted at eight epochs over an interval of six years, reveals a clear relativistic astrometric deflection of the background star's apparent position. Ground-based photometry shows a parallactic signature of the effect of the Earth's motion on the microlensing light curve. Combining the HST astrometry with the ground-based light curve and the derived parallax, we obtain a lens mass of 7.1 +/- 1.3 M_Sun and a distance of 1.58 +/- 0.18 kpc. We show that the lens emits no detectable light, which, along with having a mass higher than is possible for a white dwarf or neutron star, confirms its BH nature. Our analysis also provides an absolute proper motion for the BH. The proper motion is offset from the mean motion of Galactic-disk stars at similar distances by an amount corresponding to a transverse space velocity of ~45 km/s, suggesting that the BH received a modest natal 'kick' from its supernova explosion. Previous mass determinations for stellar-mass BHs have come from radial-velocity measurements of Galactic X-ray binaries, and from gravitational radiation emitted by merging BHs in binary systems in external galaxies. Our mass measurement is the first ever for an isolated stellar-mass BH using any technique
- …
