200 research outputs found

    Mexican-American Adolescents’ Gender-Typed Characteristics: The Role of Sibling and Friend Characteristics

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    This study examined the role of sibling and friend characteristics in Mexican-American youth’s gender-typed characteristics (i.e., attitudes, interests, and leisure activities) in early versus middle adolescence using a sibling design. Mexican-American 7th graders (M = 12.51 years; SD = .58) and their older siblings (M = 15.48 years; SD = 1.57) from 246 families participated in home interviews and a series of seven nightly phone calls. Results revealed that younger/early adolescent siblings reported more traditional gender role attitudes than their older/middle adolescent siblings and older brothers were more traditional in their attitudes than older sisters. When comparing siblings’ gender-typed interests and leisure activities, boys reported more masculine orientations than girls and girls reported more feminine orientations than boys. Older brothers’ gender-typed characteristics were associated with the amount of time spent with and gender characteristics of their friendship group, but for younger brothers, sibling characteristics were associated with their gender-typed characteristics. In contrast, both sibling and friendship characteristics were significantly associated with older and younger sisters’ gender-typed characteristics. The discussion addressed the different correlates of older and younger sisters’ and brothers’ gender-typed characteristics

    A Single Scale Theory for Cold and Hot Dark Matter

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    We show that a recently proposed extension of the MSSM can provide a scenario where both the cold and hot dark matter of the universe owe their origin to a single scale connected with the breakdown of the global B-L symmetry. The susy partner of the majoron and the light Majorana neutrinos are the cold and hot dark matter candidates respectively in this model and their desired relative abundances emerge when the scale of B-L symmetry breaking is in the TeV range.Comment: UMD-PP-94-102 (latex file; 15 pages

    Type Ia Supernovae: An Examination of Potential Progenitors and the Redshift Distribution

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    We examine the possibility that supernovae type Ia (SN Ia) are produced by white dwarfs accreting from Roche-lobe filling evolved companions, under the assumption that a strong optically thick stellar wind from accretor is able to stabilize the mass transfer. We show that if a mass transfer phase on a thermal timescale precedes a nuclear burning driven phase, then such systems (of which the supersoft X-ray sources are a subgroup) can account for about 10% of the inferred SN Ia rate. In addition, we examine the cosmic history of the supernova rate, and we show that the ratio of the rate of SN Ia to the rate of supernovae produced by massive stars (supernovae of types II, Ib, Ic) should increase from about z = 1 towards lower redshifts.Comment: 29 pages, Latex, 6 figures, aasms4.sty, psfig.sty, to appear in The Astrophysical Journa

    The absolute infrared magnitudes of type Ia supernovae

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    The absolute luminosities and homogeneity of early-time infrared (IR) light curves of type Ia supernovae are examined. Eight supernovae are considered. These are selected to have accurately known epochs of maximum blue light as well as having reliable distance estimates and/or good light curve coverage. Two approaches to extinction correction are considered. Owing to the low extinction in the IR, the differences in the corrections via the two methods are small. Absolute magnitude light curves in the J, H and K-bands are derived. Six of the events, including five established ``Branch-normal'' supernovae show similar coeval magnitudes. Two of these, SNe 1989B and 1998bu, were observed near maximum infrared light. This occurs about 5 days {\it before} maximum blue light. Absolute peak magnitudes of about -19.0, -18.7 and -18.8 in J, H & K respectively were obtained. The two spectroscopically peculiar supernovae in the sample, SNe 1986G and 1991T, also show atypical IR behaviour. The light curves of the six similar supernovae can be represented fairly consistently with a single light curve in each of the three bands. In all three IR bands the dispersion in absolute magnitude is about 0.15 mag, and this can be accounted for within the uncertainties of the individual light curves. No significant variation of absolute IR magnitude with B-band light curve decline rate, Delta m_{15}(B), is seen over the range 0.87<Delta m_{15}(B)<1.31. However, the data are insufficient to allow us to decide whether or not the decline rate relation is weaker in the IR than in the optical region. IR light curves of type Ia supernovae should eventually provide cosmological distance estimates which are of equal or even superior quality to those obtained in optical studies.Comment: 19 pages, 9 figures, MNRAS in press (includes Referee's changes

    Quantum phase transition in the Frenkel-Kontorova chain: from pinned instanton glass to sliding phonon gas

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    We study analytically and numerically the one-dimensional quantum Frenkel-Kontorova chain in the regime when the classical model is located in the pinned phase characterized by the gaped phonon excitations and devil's staircase. By extensive quantum Monte Carlo simulations we show that for the effective Planck constant \hbar smaller than the critical value c\hbar_c the quantum chain is in the pinned instanton glass phase. In this phase the elementary excitations have two branches: phonons, separated from zero energy by a finite gap, and instantons which have an exponentially small excitation energy. At =c\hbar=\hbar_c the quantum phase transition takes place and for >c\hbar>\hbar_c the pinned instanton glass is transformed into the sliding phonon gas with gapless phonon excitations. This transition is accompanied by the divergence of the spatial correlation length and appearence of sliding modes at >c\hbar>\hbar_c.Comment: revtex 16 pages, 18 figure

    Patient-Reported Outcomes Through 1 Year of an HIV-1 Clinical Trial Evaluating Long-Acting Cabotegravir and Rilpivirine Administered Every 4 or 8 Weeks (ATLAS-2M)

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    BACKGROUND: Advances in HIV-1 therapeutics have led to the development of a range of daily oral treatment regimens, which share similar high efficacy rates. Consequently, more emphasis is being placed upon the individual\u27s experience of treatment and impact on quality of life. The first long-acting injectable antiretroviral therapy for HIV-1 (long-acting cabotegravir + rilpivirine [CAB + RPV LA]) may address challenges associated with oral treatment for HIV-1, such as stigma, pill burden/fatigue, drug-food interactions, and adherence. Patient-reported outcomes (PROs) collected in an HIV-1 clinical trial (ATLAS-2M; NCT03299049) comparing participants\u27 experience with two dosing regimens (every 4 weeks [Q4W] vs. every 8 weeks [Q8W]) of CAB + RPV LA are presented herein. METHODS: PRO endpoints evaluated through 48 weeks of therapy included treatment satisfaction (HIV Treatment Satisfaction Questionnaire [HIVTSQ]), treatment acceptance ( General Acceptance domain of the Chronic Treatment Acceptance [ACCEPT RESULTS: Overall, 1045 participants were randomized to the Q8W (n = 522) and Q4W (n = 523) regimens; 37% (n = 391/1045) had previously received CAB + RPV in ATLAS. For participants without prior CAB + RPV exposure, large increases from baseline were reported in treatment satisfaction in both long-acting arms (HIVTSQ status version), with Q8W dosing statistically significantly favored at Weeks 24 (p = 0.036) and 48 (p = 0.004). Additionally, improvements from baseline were also observed in the General Acceptance domain of the ACCEPT questionnaire in both long-acting arms for participants without prior CAB + RPV exposure; however, no statistically significant difference was observed between arms at either timepoint (Week 24, p = 0.379; Week 48, p = 0.525). Significant improvements (p \u3c 0.001) in the Acceptance of Injection Site Reactions domain of the PIN questionnaire were observed from Week 8 to Weeks 24 and 48 in both arms for participants without prior CAB + RPV exposure. Participants with prior CAB + RPV exposure reported high treatment satisfaction (mean [HIVTSQ status version]: Q8W 62.2/66.0; Q4W 62.0/66.0), treatment acceptance (mean: Q8W 89.3/100; Q4W 91.2/100), and acceptance of injection site reactions (mean [5 = not at all acceptable; 1 = totally acceptable]: Q8W 1.72; Q4W 1.59) at baseline/Week 8 that were maintained over time. Participants without prior CAB + RPV exposure who received Q8W dosing preferred this regimen over oral CAB + RPV (98%, n = 300/306). Among those with prior Q4W exposure, 94% (n = 179/191) preferred Q8W dosing versus Q4W dosing (3%, n = 6/191) or oral CAB + RPV (2%, n = 4/191). CONCLUSIONS: Both long-acting regimens provided high treatment satisfaction and acceptance, irrespective of prior CAB + RPV exposure, with most participants preferring Q8W dosing over both the Q4W regimen and their previous daily oral regimen. The PRO data collected at Week 48 support the therapeutic potential of CAB + RPV LA. FUNDING: ViiV Healthcare and Janssen. TRIAL REGISTRATION: ATLAS-2M: ClinicalTrials.gov NCT03299049, registered October 2, 2017

    Unemployment Insurance and Low-Educated Single Working Mothers Before and After Welfare Reform

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    Using the Survey of Income and Program Participation (SIPP), a nationally representative, longitudinal survey, this study examines changing levels of Unemployment Insurance (UI) eligibility and benefit receipt among working low-educated single mothers, 1990–2005. It also examines changing participation in cash welfare and the Food Stamp Program (FSP). Relative to single childless women, there has been no increase in UI benefit receipt among single mothers entering a spell of unemployment in the postreform period, even though single mothers have increased their relative rates of UI eligibility. Because of declining cash assistance receipt, UI became a more common income support than cash assistance for this population during the period 2001–2005. Furthermore, the probability of accessing FSP for low-educated single mothers entering a spell of unemployment increased in the years 2001–2005. As a result, the proportion of this population accessing benefits from one or more of these programs remained virtually unchanged across the study period

    Cost Effectiveness of a Pharmacy-Only Refill Program in a Large Urban HIV/AIDS Clinic in Uganda

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    HIV/AIDS clinics in Uganda and other low-income countries face increasing numbers of patients and workforce shortages. We performed a cost-effectiveness analysis comparing a Pharmacy-only Refill Program (PRP), a form of task-shifting, to the Standard of Care (SOC) at a large HIV/AIDS clinic in Uganda, the Infectious Diseases Institute (IDI). The PRP was started to reduce workforce shortages and optimize patient care by substituting pharmacy visits for SOC involving monthly physician visits for accessing antiretroviral medicines.We used a retrospective cohort analysis to compare the effectiveness of the PRP compared to SOC. Effectiveness was defined as Favorable Immune Response (FIR), measured as having a CD4 lymphocyte count of over 500 cells/µl at follow-up. We used multivariate logistic regression to assess the difference in FIR between patients in the PRP and SOC. We incorporated estimates of effectiveness into an incremental cost-effectiveness analysis performed from a limited societal perspective. We estimated costs from previous studies at IDI and conducted univariate and probabilistic sensitivity analyses. We identified 829 patients, 578 in the PRP and 251 in SOC. After 12.8 months (PRP) and 15.1 months (SOC) of follow-up, 18.9% of patients had a FIR, 18.6% in the PRP and 19.6% in SOC. There was a non-significant 9% decrease in the odds of having a FIR for PRP compared to SOC after adjusting for other variables (OR 0.93, 95% CI 0.55-1.58). The PRP was less costly than the SOC (US520vs.655annually,respectively).TheincrementalcosteffectivenessratiocomparingPRPtoSOCwasUS 520 vs. 655 annually, respectively). The incremental cost-effectiveness ratio comparing PRP to SOC was US 13,500 per FIR. PRP remained cost-effective at univariate and probabilistic sensitivity analysis.The PRP is more cost-effective than the standard of care. Similar task-shifting programs might help large HIV/AIDS clinics in Uganda and other low-income countries to cope with increasing numbers of patients seeking care
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