1,181 research outputs found
The Relationship between Cost Analysis and Program Management
Cost analysis if often viewed as applying basic principles and cost methodologies to determine total system cost. These finished estimates then flow into a decision making process and the cost estimator leaves the stage. Reality shows that the cost estimator is actually one of the main contributors to the decision making process. Our introduction to this special issue explores the areas where cost estimating plays a major role in program management in areas beyond the normal program estimate. We have included articles that show the key role estimators can play in source selection strategies and evaluation; cost of delay analysis for management decisions, earned value management methods to predict program costs; decision criteria to rank competing projects that complement traditional cost-based methods; and a new methodology for determining research and development budget profiles
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Grindr Users Take More Risks, but Are More Open to Human Immunodeficiency Virus (HIV) Pre-exposure Prophylaxis: Could This Dating App Provide a Platform for HIV Prevention Outreach?
BackgroundTechnology has changed the way that men who have sex with men (MSM) seek sex. More than 60% of MSM in the United States use the internet and/or smartphone-based geospatial networking apps to find sex partners. We correlated use of the most popular app (Grindr) with sexual risk and prevention behavior among MSM.MethodsA nested cohort study was conducted between September 2018 and June 2019 among MSM receiving community-based human immunodeficiency virus (HIV) and sexually transmitted infection (STI) screening in central San Diego. During the testing encounter, participants were surveyed for demographics, substance use, risk behavior (previous 3 months), HIV pre-exposure prophylaxis (PrEP) use, and Grindr usage. Participants who tested negative for HIV and who were not on PrEP were offered immediate PrEP.ResultsThe study included 1256 MSM, 1090 of whom (86.8%) were not taking PrEP. Overall, 580 of 1256 (46%) participants indicated that they used Grindr in the previous 7 days. Grindr users reported significantly higher risk behavior (greater number of male partners and condomless sex) and were more likely to test positive for chlamydia or gonorrhea (8.6% vs 4.7% of nonusers; P = .005). Grindr users were also more likely to be on PrEP (18.7% vs 8.7% of nonusers; P < .001) and had fewer newly diagnosed HIV infections (9 vs 26 among nonusers; P = .014). Grindr users were also nearly twice as likely as nonusers to initiate PrEP (24.6% vs 14%; P < .001).ConclusionsGiven the higher risk behavior and greater acceptance of PrEP among MSM who used Grindr, Grindr may provide a useful platform to promote HIV and STI testing and increase PrEP uptake
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âI Would Absolutely Need to Know That My Partner Is Still Going to be Protectedâ: Perceptions of HIV Cure-Related Research Among Diverse HIV Serodifferent Couples in the United States
Most HIV cure studies remain in the early stage of investigation and may carry clinical risks to the participants and, in some cases, their partners. Surprisingly little sociobehavioral research has investigated the perceptions of couples-including HIV serodifferent couples-around HIV cure research, including factors that would influence recruitment and retention in trials. We conducted a qualitative study to explore perceptions of diverse HIV serodifferent partners in the United States. We recruited 10 diverse HIV serodifferent couples (20 participants). We found participants had learned to cope with the reality of HIV, including protections during sex, and ascribed both positive and negative meanings to an HIV cure. Partners expressed concern about each other's health and potentially caring for a sick partner and emphasized the importance of safety when participating in an HIV cure trial. They identified the need for partner protection measures during analytical treatment interruptions (ATIs) as an ethical imperative. Participants recounted experiences of HIV stigma due to being in HIV serodifferent relationships and viewed ATIs as leading to a detectable viral load, which could limit sexual expression, complicate disclosure decision making, and worsen HIV-related stigma. Our study's main contribution is to inform efforts to meaningfully engage diverse HIV serodifferent partners in HIV cure research in the United States. Our data suggest people with HIV make decisions to participate in research based on close ones in their life and underscore the critical importance of acknowledging relationship dynamics in decisions to participate in research
Metal nanofilm in strong ultrafast optical fields
We predict that a metal nanofilm subjected to an ultrashort (single
oscillation) optical pulse of a high field amplitude at
normal incidence undergoes an ultrafast (at subcycle times ) transition to a state resembling semimetal. Its reflectivity is
greatly reduced, while the transmissivity and the optical field inside the
metal are greatly increased. The temporal profiles of the optical fields are
predicted to exhibit pronounced subcycle oscillations, which are attributed to
the Bloch oscillations and formation of the Wannier-Stark ladder of electronic
states. The reflected, transmitted, and inside-the-metal pulses have non-zero
areas approaching half-cycle pulses. The effects predicted are promising for
applications to nanoplasmonic modulators and field-effect transistors with
petahertz bandwidth
The Three Dimensional Structure of EUV Accretion Regions in AM Herculis Stars: Modeling of EUV Photometric and Spectroscopic Observations
We have developed a model of the high-energy accretion region for magnetic
cataclysmic variables and applied it to {\it Extreme Ultraviolet Explorer}
observations of 10 AM Herculis type systems. The major features of the EUV
light curves are well described by the model. The light curves exhibit a large
variety of features such as eclipses of the accretion region by the secondary
star and the accretion stream, and dips caused by material very close to the
accretion region. While all the observed features of the light curves are
highly dependent on viewing geometry, none of the light curves are consistent
with a flat, circular accretion spot whose lightcurve would vary solely from
projection effects. The accretion region immediately above the WD surface is a
source of EUV radiation caused by either a vertical extent to the accretion
spot, or Compton scattering off electrons in the accretion column, or, very
likely, both. Our model yields spot sizes averaging 0.06 R, or the WD surface area, and average spot heights of 0.023
R. Spectra extracted during broad dip phases are softer than spectra
during the out-of-dip phases. This spectral ratio measurement leads to the
conclusion that Compton scattering, some absorption by a warm absorber,
geometric effects, an asymmetric temperature structure in the accretion region
and an asymmetric density structure of the accretion columnare all important
components needed to fully explain the data. Spectra extracted at phases where
the accretion spot is hidden behind the limb of the WD, but with the accretion
column immediately above the spot still visible, show no evidence of emission
features characteristic of a hot plasma.Comment: 30 Pages, 11 Figure
Substance Use Disorders, Violence, Mental Health, and HIV: Differentiating a Syndemic Factor by Gender and Sexuality
This paper measures syndemic substance use disorder, violence, and mental health and compares the syndemic among HIV-infected heterosexual men, heterosexual women, and men who have sex with men (MSM). Data were from a sample of high needs substance-using, HIV-infected people in South Florida between 2010 and 2012 (n = 481). We used confirmatory factor analysis to measure a syndemic latent variable and applied measurement invariance models to identify group differences in the data structure of syndemic co-morbidities among heterosexual men, heterosexual women, and MSM. We found that variables used to measure the syndemic fit each sub-group, supporting that substance use disorder, violence, and mental health coincide in HIV-infected individuals. Heterosexual men and MSM demonstrated similar syndemic latent variable factor loadings, but significantly different item intercepts, indicating that heterosexual men had larger mean values on substance use disorder, anxiety, and depression than MSM. Heterosexual men and heterosexual women demonstrated significantly different syndemic variable factor loadings, indicating that anxiety and depression contribute more (and substance use contributes less) to the syndemic in heterosexual men compared to heterosexual women. MSM and heterosexual women demonstrated similar syndemic latent variable factor loadings and intercepts, but had significantly different factor residual variances indicating more variance in violent victimization and depression for MSM and more variance in stress for heterosexual women than what is captured by the observed syndemic indicators. Furthermore, heterosexual women had a larger syndemic factor mean than MSM, indicating that the syndemic burden is greater among heterosexual women than MSM. Our findings support that measurement invariance can elucidate differences in the syndemic to tailor interventions to sub-group needs
Simultaneous optical polarimetry and X-ray data of the near synchronous polar RX J2115-5840
We present simultaneous optical polarimetry and X-ray data of the near
synchronous polar RX J2115-5840. We model the polarisation data using the
Stokes imaging technique of Potter et al. We find that the data are best
modelled using a relatively high binary inclination and a small angle between
the magnetic and spin axes. We find that for all spin-orbit beat phases, a
significant proportion of the accretion flow is directed onto the lower
hemisphere of the white dwarf, producing negative circular polarisation. Only
for a small fraction of the beat cycle is a proportion of the flow directed
onto the upper hemisphere. However, the accretion flow never occurs near the
upper magnetic pole, whatever the orientation of the magnetic poles. This
indicates the presence of a non-dipole field with the field strength at the
upper pole significantly higher. We find that the brightest parts of the hard
X-ray emitting region and the cyclotron region are closely coincident.Comment: 9 pages, accepted for publication in MNRAS 2 March 200
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Masculinity and engagement in HIV care among male fisherfolk on HIV treatment in Uganda.
This study explored the intersection of masculinity and HIV care engagement among fishermen and other male fisherfolk on antiretroviral therapy (ART) in Wakiso District, Uganda. We conducted 30 in-depth interviews with men on ART recruited from HIV treatment sites and used a thematic analysis approach. Since HIV diagnosis and ART initiation, men had adopted masculine identities more conducive to HIV care engagement. The masculine roles of worker and provider, husband and sexual partner and the appearance of physical strength were compromised by HIV, but restored by ART's positive effects on health. Peers also emerged as facilitators to HIV care, with men supporting each other to seek testing and treatment. However, structural and occupational barriers to HIV care associated with the masculine role of worker remained a barrier to care engagement. Findings suggest that emphasising the benefits of ART in bolstering men's ability to fulfil the roles important to them may improve the effectiveness of HIV testing and treatment messaging for men. Differentiated care models that address structural-level barriers to care, and community-level gender-transformative programming to help fishermen engage in HIV care, may be beneficial
Mesoscopic Cooperative Emission From a Disordered System
We study theoretically the cooperative light emission from a system of classical oscillators confined within a volume with spatial scale, , much
smaller than the radiation wavelength, . We assume
that the oscillators frequencies are randomly distributed around a central
frequency, , with some characteristic width, . In
the absence of disorder, that is , the cooperative emission spectrum
is composed of a narrow subradiant peak superimposed on a wide superradiant
band. When , we demonstrate that if is large enough, the
subradiant peak is not simply broadened by the disorder but rather splits into
a system of random narrow peaks. We estimate the spectral width of these peaks
as a function of , and . We also estimate the
amplitude of this mesoscopic structure in the emission spectrum.Comment: 25 pages including 6 figure
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