Optimizing the third-and-a-half post-Newtonian gravitational radiation-reaction force for numerical simulations

The gravitational radiation-reaction force acting on perfect fluids at 3.5 post-Newtonian order is cast into a form which is directly applicable to numerical simulations. Extensive use is made of metric-coefficient changes induced by functional coordinate transformations, of the continuity equation, as well as of the equations of motion. We also present an expression appropriate for numerical simulations of the radiation field causing the worked out reaction force.Comment: 22 pages to appear in Physical Review

Oscillation of the tunnel splitting in nanospin systems within the particle mapping formalism

The oscillation of tunnel splitting in the biaxial spin system within magnetic field along the anisotropy axis is analyzed within the particle mapping approach, rather than in the (\theta-\phi) spin coherent-state representation. In our mapping procedure, the spin system is transformed into a particle moving in the restricted $S^1$ geometry whose wave function subjects to the boundary condition involving additional phase shift. We obtain the new topological phase that plays the same role as the Wess-Zumino action in spin coherent-state representation. Considering the interference of two possible trajectories, instanton and anti-instanton, we get the identical condition for the field at which tunneling is quenched, with the previous result within spin coherent-state representation.Comment: 11 pages, 1 figure; Some typographical errors have been correcte

Relaxation and Landau-Zener experiments down to 100 mK in ferritin

Temperature-independent magnetic viscosity in ferritin has been observed from 2 K down to 100 mK, proving that quantum tunneling plays the main role in these particles at low temperature. Magnetic relaxation has also been studied using the Landau-Zener method making the system crossing zero resonant field at different rates, alpha=dH/dt, ranging from 10^{-5} to 10^{-3} T/s, and at different temperatures, from 150 mK up to the blocking temperature. We propose a new Tln(Delta H_{eff}/tau_0 alpha) scaling law for the Landau-Zener probability in a system distributed in volumes, where Delta H_{eff} is the effective width of the zero field resonance.Comment: 13 pages, 4 postscript figure

On the Evolution Equation for Magnetic Geodesics

In this paper we prove the existence of long time solutions for the parabolic equation for closed magnetic geodesics.Comment: In this paper we prove the existence of long time solutions for the parabolic equation for closed magnetic geodesic

Religious Freedom Restoration Acts and Sexual Minority Population Health in the United States

Religious freedom restoration acts (RFRAs) in the United States potentially facilitate discrimination against lesbian, gay, and bisexual individuals (i.e., sexual minorities). In the current investigation, we explored whether a population health metric among sexual minority adults changed over time based on the presence, absence, or introduction of a state RFRA. Data are from 21 of the United States that gathered sexual orientation data from population-based samples of noninstitutionalized adults in the 2015 Behavioral Risk Factor Surveillance System (CDC, 2015, 2016). The analytic sample included 4,911 sexual minority individuals. Time was measured in 4 3-month quarters (i.e., Q1, Q2, Q3, Q4). For each state, the prevalence of sexual minority adults reporting =14 unhealthy days/30 days was calculated. Only Indiana (the only state in the sample that passed an RFRA in 2015) exhibited significant increasing proportions over time of sexual minority adults reporting =14 unhealthy days (Q1 = 24.5%, Q2 = 34.8%, Q3 = 41.2%, Q4 = 59.5%; β = 0.50, SE = 0.23, p = .037). Post hoc analyses revealed that unhealthy days did not increase for heterosexual adults in Indiana. Indiana's RFRA could have contributed to the increasing prevalence of unhealthy days among sexual minority adults in that state during 2015. Public health surveillance tools are needed to expedite analyses of the impact of laws on minority population health

High frequency resonant experiments in Fe8_8 molecular clusters

Precise resonant experiments on Fe$_{8}$ magnetic clusters have been conducted down to 1.2 K at various tranverse magnetic fields, using a cylindrical resonator cavity with 40 different frequencies between 37 GHz and 110 GHz. All the observed resonances for both single crystal and oriented powder, have been fitted by the eigenstates of the hamiltonian ${\cal H}=-DS_z^2+ES_x^2-g\mu_B{\bf H}\cdot {\bf S}$. We have identified the resonances corresponding to the coherent quantum oscillations for different orientations of spin S = 10.Comment: to appear in Phys.Rev. B (August 2000

Black Men Who Have Sex with Men and Lifetime HIV Testing: Characterizing the Reasons and Consequences of Having Never Tested for HIV

HIV testing remains a critical point of entry to HIV treatment services and now biomedical prevention as well. Yet despite the high HIV prevalence among Black men who have sex with men (MSM), insufficient attention has been given to factors associated with those Black MSM in the United States who have never received an HIV test in their lifetime. Promoting Our Worth, Equality, & Resilience (POWER) is a cross-sectional observational study that recruited Black MSM at Black Pride events across six cities in the United States from 2014 to 2017. Participants completed an anonymous questionnaire and were offered free, confidential HIV testing. Of the 4174 Black MSM without a prior HIV diagnosis, 404 (9.68%) had never tested for HIV (mean age = 31.03 years). Lower education and greater internalized homophobia were associated with never having tested for HIV. Higher age (AOR = 1.05, 95%, 1.02–1.07) and assumption of HIV-positivity (AOR = 3.24, 95% CI 1.53–6.84) were both associated with increased odds of an HIV-positive test result (n = 119; 36%). To compare, HIV prevalence among Black MSM who had received at least one HIV test before study participation was 23%. While a minority of Black MSM had never received an HIV test, this group had a significantly higher likelihood of HIV infection. Alternative HIV testing strategies are needed to facilitate HIV testing initiation among Black MSM for whom conventional HIV testing modalities are insufficient

Psychosocial Health Disparities Among Black Bisexual Men in the U.S.: Effects of Sexuality Nondisclosure and Gay Community Support

Compared with Black gay men, Black bisexual men experience psychosocial health disparities, including depression, polydrug use, physical assault, and intimate partner violence (IPV). Black bisexual men are also less likely to disclose their sexuality, which may result in them receiving less sexual minority community support, exacerbating psychosocial health disparities. We assessed relationships between bisexual behavior, bisexual identity, sexuality nondisclosure, gay community support, and psychosocial morbidities among Black men who have sex with men (MSM). Between 2014 and 2017, survey data were collected from Black MSM ≥ 18 years old (n = 4430) at Black Pride events in six U.S. cities. We differentiated between bisexual-identified men reporting past-year sex with men and women (bisexual MSMW, 8.4%); gay-identified men reporting sex with men only (gay MSMO, 73.1%); gay MSMW (8.0%); and bisexual MSMO (8.4%). Multivariable regressions contrasted these groups by psychosocial morbidities, sexuality nondisclosure, and gay community support. Structural equation models assessed total, direct, and indirect effects. Compared with gay MSMO, bisexual MSMW and gay MSMW were significantly more likely to report polydrug use, depression symptoms, IPV, physical assault, sexuality nondisclosure, and lack of gay community support. Lack of gay community support had significant indirect effects on the relationships between bisexual behavior and psychosocial morbidity (p < .001) and between bisexual identity and psychosocial morbidity (p < .001). Sexuality nondisclosure had significant indirect effects on relationships between bisexual behavior (p < .001), bisexual identity (p < .001), and lack of gay community support. Psychosocial health disparities experienced by Black bisexual men are associated with both bisexual behavior and bisexual identity. Interventions decreasing biphobia will facilitate opportunities for protective sexuality disclosure and access to sexual minority community support

Running Backwards: Consequences of Current HIV Incidence Rates for the Next Generation of Black MSM in the United States

Black men who have sex with men (MSM) in the United States are disproportionately impacted by HIV. To better understand this public health problem, we reviewed the literature to calculate an estimate of HIV incidence among Black MSM. We used this rate to model HIV prevalence over time within a simulated cohort, which we subsequently compared to prevalence from community-based samples. We searched all databases accessible through PubMed, and Conference on Retroviruses and Opportunistic Infections abstracts for HIV incidence estimates among Black MSM. Summary HIV incidence rates and 95 % confidence intervals (CIs) were calculated using random effects models. Using the average incidence rate, we modeled HIV prevalence within a simulated cohort of Black MSM (who were all HIV-negative at the start) from ages 18 through 40. Based on five incidence rates totaling 2898 Black MSM, the weighted mean incidence was 4.16 % per year (95 % CI 2.76–5.56). Using this annual incidence rate, our model predicted that 39.94 % of Black MSM within the simulated cohort would be HIV-positive by age 30, and 60.73 % by 40. Projections were similar to HIV prevalence found in community-based samples of Black MSM. High HIV prevalence will persist across the life-course among Black MSM, unless effective prevention and treatment efforts are increased to substantially reduce HIV transmission among this underserved and marginalized population

Theoretical study of the absorption spectra of the sodium dimer

Absorption of radiation from the sodium dimer molecular states correlating to Na(3s)-Na(3s) is investigated theoretically. Vibrational bound and continuum transitions from the singlet X Sigma-g+ state to the first excited singlet A Sigma-u+ and singlet B Pi-u states and from the triplet a Sigma-u+ state to the first excited triplet b Sigma-g+ and triplet c Pi-g states are studied quantum-mechanically. Theoretical and experimental data are used to characterize the molecular properties taking advantage of knowledge recently obtained from ab initio calculations, spectroscopy, and ultra-cold atom collision studies. The quantum-mechanical calculations are carried out for temperatures in the range from 500 to 3000 K and are compared with previous calculations and measurements where available.Comment: 19 pages, 8 figures, revtex, eps