946 research outputs found
When Spreading HIV May Matter Most: The Unclassifiable Sexual Non-Identity Of Adolescent African American MSMW On Their Journey To Testing
Recent studies have found that many young African American men who have sex with men and women (MSMW) do not identify as bisexual or non-heterosexual. The present study explored the mental journeys of twenty African American MSMW as they decided to undergo HIV testing. The rejection of sexual identity labels may contribute to the rising annual HIV infection rate among African American men who have sex with men (MSM) and MSMW. Furthermore, sexual identity ambivalence may lead to secretive sexual behavior and failure to disclose homosexual relations to female partners, behavior colloquially referred to as “down-low.” Greater understanding of the nuanced distinctions between sexual identity and behavior may help public health researchers address the needs of this racial and sexual minority that remains especially vulnerable to HIV/AIDS.
Two roles of relativistic spin operators
Operators that are associated with several important quantities, like angular
momentum, play a double role: they are both generators of the symmetry group
and ``observables.'' The analysis of different splittings of angular momentum
into "spin" and "orbital" parts reveals the difference between these two roles.
We also discuss a relation of different choices of spin observables to the
violation of Bell inequalities.Comment: RevTeX 4, 4 pages A discussion on relation of different choices of
spin observables to the observed violation of Bell inequalities is added,
some misprints corrected and the presentation is clarifie
Options to Accelerate Ozone Recovery: Ozone and Climate Benefits
The humankind or anthropogenic influence on ozone primarily originated from the chlorofluorocarbons and halons (chlorine and bromine). Representatives from governments have met periodically over the years to establish international regulations starting with the Montreal Protocol in 1987, which greatly limited the release of these ozone-depleting substances (DDSs). Two global models have been used to investigate the impact of hypothetical reductions in future emissions of ODSs on total column ozone. The investigations primarily focused on chlorine- and bromine-containing gases, but some computations also included nitrous oxide (N2O). The Montreal Protocol with ODS controls have been so successful that further regulations of chlorine- and bromine-containing gases could have only a fraction of the impact that regulations already in force have had. if all anthropogenic ODS emissions were halted beginning in 2011, ozone is calculated to be higher by about 1-2% during the period 2030-2100 compared to a case of no additional ODS restrictions. Chlorine- and bromine-containing gases and nitrous oxide are also greenhouse gases and lead to warming of the troposphere. Elimination of N 20 emissions would result in a reduction of radiative forcing of 0.23 W/sq m in 2100 than presently computed and destruction of the CFC bank would produce a reduction in radiative forcing of 0.005 W/sq m in 2100. This paper provides a quantitative way to consider future regulations of the CFC bank and N 20 emission
Youth sport during the COVID-19 pandemic: The influence of race and affluence on parents’ perspectives of youth participation
COVID-19 restrictions led to a nearly 50% decline in youth sport participation across the United States (Dorsch et al., 2021). Today, communities and sport organizations have resumed sport. However, research has yet to fully elucidate how COVID-19 restrictions impacted youth participation across different sociodemographic groups during the pandemic. The present study explored the association between race and affluence and their relationship with parents' attitudes toward children's youth sport participation before, during, and after the COVID-19 pandemic. Online questionnaires were completed by a nationally representative sample of 3706 parents (Mage = 39.57 ± 9.03 years) who had a child regularly participating in youth sport before COVID-19. Multivariate Analyses of Variance using Tukey post-hoc tests were conducted to examine the main effect differences by race and affluence and the interactive effects of race and affluence. Results suggest that race and affluence -- independently and in combination -- were salient categorical variables of children's weekly hours of sport participation during the COVID-19 pandemic. Findings highlight that White*high affluent groups had the highest rates of sport participation during the COVID-19 pandemic and that these families desire to invest more time and money at greater rates upon returning. Theoretically, designed intersectionality research is recommended to explore further effects of race and affluence in youth sport
Facile one-pot synthesis of amoxicillin-coated gold nanoparticles and their antimicrobial activity
Nanomaterials have been the object of intense study due to promising applications in a number of different disciplines. In particular, medicine and biology have seen the potential of these novel materials with their nanoscale properties for use in diverse areas such as imaging, sensing and drug vectorisation. Gold nanoparticles (GNPs) are considered a very useful platform to create a valid and efficient drug delivery/carrier system due to their facile and well-studied synthesis, easy surface functionalization and biocompatibility. In the present study, stable antibiotic conjugated GNPs were synthesised by a one-step reaction using a poorly water soluble antibiotic, amoxicillin. Amoxicillin, a member of the penicillin family, reduces the chloroauric acid to form nanoparticles and at the same time coats them to afford the functionalised nanomaterial. A range of techniques including UV-vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) were used to ascertain the gold/drug molar ratio and the optimum temperature for synthesis of uniform monodisperse particles in the ca. 30-40 nm size range. Amoxicillin-conjugated gold showed an enhancement of antibacterial activity against Escherichia coli compared to the antibiotic alone
The GALEX View of "Boyajian's Star" (KIC 8462852)
The enigmatic star KIC 8462852, informally known as "Boyajian's Star", has
exhibited unexplained variability from both short timescale (days) dimming
events, and years-long fading in the Kepler mission. No single physical
mechanism has successfully explained these observations to date. Here we
investigate the ultraviolet variability of KIC 8462852 on a range of timescales
using data from the GALEX mission that occurred contemporaneously with the
Kepler mission. The wide wavelength baseline between the Kepler and GALEX data
provides a unique constraint on the nature of the variability. Using 1600
seconds of photon-counting data from four GALEX visits spread over 70 days in
2011, we find no coherent NUV variability in the system on 10-100 second or
months timescales. Comparing the integrated flux from these 2011 visits to the
2012 NUV flux published in the GALEX-CAUSE Kepler survey, we find a 3% decrease
in brightness for KIC 8462852. We find this level of variability is
significant, but not necessarily unusual for stars of similar spectral type in
the GALEX data. This decrease coincides with the secular optical fading
reported by Montet & Simon (2016). We find the multi-wavelength variability is
somewhat inconsistent with typical interstellar dust absorption, but instead
favors a R = 5.0 0.9 reddening law potentially from circumstellar
dust.Comment: 8 pages, 4 figures, ApJ Accepte
Incremental bounded model checking for embedded software
Program analysis is on the brink of mainstream usage in embedded systems development. Formal verification of behavioural requirements, finding runtime errors and test case generation are some of the most common applications of automated verification tools based on bounded model checking (BMC). Existing industrial tools for embedded software use an off-the-shelf bounded model checker and apply it iteratively to verify the program with an increasing number of unwindings. This approach unnecessarily wastes time repeating work that has already been done and fails to exploit the power of incremental SAT solving. This article reports on the extension of the software model checker CBMC to support incremental BMC and its successful integration with the industrial embedded software verification tool BTC EMBEDDED TESTER. We present an extensive evaluation over large industrial embedded programs, mainly from the automotive industry. We show that incremental BMC cuts runtimes by one order of magnitude in comparison to the standard non-incremental approach, enabling the application of formal verification to large and complex embedded software. We furthermore report promising results on analysing programs with arbitrary loop structure using incremental BMC, demonstrating its applicability and potential to verify general software beyond the embedded domain
The Long-term Middle Atmospheric Influence of Very Large Solar Proton Events
Long-term variations in ozone have been caused by both natural and humankind related processes. The humankind or anthropogenic influence on ozone originates from the chlorofluorocarbons and halons (chlorine and bromine) and has led to international regulations greatly limiting the release of these substances. Certain natural ozone influences are also important in polar regions and are caused by the impact of solar charged particles on the atmosphere. Such natural variations have been studied in order to better quantify the human influence on polar ozone. Large-scale explosions on the Sun near solar maximum lead to emissions of charged particles (mainly protons and electrons), some of which enter the Earth's magnetosphere and rain down on the polar regions. "Solar proton events" have been used to describe these phenomena since the protons associated with these solar events sometimes create a significant atmospheric disturbance. We have used the National Center for Atmospheric Research (NCAR) Whole Atmosphere Community Climate Model (WACCM) to study the long-term (> few months) influences of solar proton events from 1963 through 2004 on stratospheric ozone and temperature. There were extremely large solar proton events in 1972, 1989,2000,2001, and 2003. These events caused very distinctive polar changes in layers of the Earth's atmosphere known as the stratosphere (12-50 km; -7-30 miles) and mesosphere (50-90 km; 30-55 miles). The solar protons connected with these events created hydrogen- and nitrogen-containing compounds, which led to the polar ozone destruction. The nitrogen-containing compounds, called odd nitrogen, lasted much longer than the hydrogen-containing compounds and led to long-lived stratospheric impacts. An extremely active period for these events occurred in the five-year period, 2000- 2004, and caused increases in odd nitrogen which lasted for several months after individual events. Associated stratospheric ozone decreases of >lo% were calculated to last for up to five months past the largest events. However, the computed total column ozone and stratospheric temperature changes connected with the solar events were not found to be statistically significant. Thus, solar proton events do not likely contribute significantly to measured total column ozone fluctuations and stratospheric temperature changes
Overview of Aerosolized Florida Red Tide Toxins: Exposures and Effects
Florida red tide is caused by Karenia brevis, a dinoflagellate that periodically blooms, releasing its potent neurotoxin, brevetoxin, into the surrounding waters and air along the coast of the Gulf of Mexico. Exposure to Florida red tide toxins has been associated with adverse human health effects and massive fish and marine mammal deaths. The articles in this mini-monograph describe the ongoing interdisciplinary and interagency research program that characterizes the exposures and health effects of aerosolized Florida red tide toxins (brevetoxins). The interdisciplinary research program uses animal models and laboratory studies to develop hypotheses and apply these findings to in situ human exposures. Our ultimate goal is to develop appropriate prevention measures and medical interventions to mitigate or prevent adverse health effects from exposure to complex mixtures of aerosolized red tide toxins
Neurodevelopmental multimorbidity and educational outcomes of Scottish schoolchildren : A population-based record linkage cohort study
Data Availability: All health data are owned by the Information Services Division of NHS National Services Scotland (https://www.isdscotland.org), and all education data are owned by the ScotXed Unit, which is part of the Educational Analytical Services Division within the Learning and Justice Directorate of the Scottish Government (www2.gov.scot/Topics/Statistics/ScotXed). Interested researchers may apply at these sites for data access. Funding: The study was sponsored by Health Data Research UK (www.hdruk.ac.uk) (grant reference number MR/S003800/1) (MF) which is a joint investment led by the Medical Research Council, together with the National Institute for Health Research (England), the Chief Scientist Office (Scotland), Health and Care Research Wales, Health and Social Care Research and Development Division (Public Health Agency, Northern Ireland), the Engineering and Physical Sciences Research Council, the Economic and Social Research Council, the British Heart Foundation and Wellcome. There was additional funding from the Carnegie Trust for the Universities of Scotland (grant reference VAC007974) (EES) and an MRC Mental Health Data Pathfinder grant (grant reference MC_PC_17217) (MF, JPP, DK, SC).Peer reviewedPublisher PD
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