666 research outputs found

    Locked entropy in partially coherent fields

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    We introduce a taxonomy for partially coherent optical fields spanning multiple degrees of freedom (DoFs) based on the rank of the associated coherence matrix (the number of non-zero eigenvalues). When DoFs comprise two spatial modes and polarization, a fourfold classification emerges, with rank-1 fields corresponding to fully coherent fields. We demonstrate theoretically and confirm experimentally that these classes have heretofore unrecognized different properties. Specifically, whereas rank-2 fields can always be rendered separable with respect to its DoFs via a unitary transformation, rank-3 fields are always non-separable. Consequently, the entropy for a rank-2 field can always be concentrated into a single DoF (thus ridding the other DoF of statistical fluctuations), whereas some entropy is always 'locked' in one DoF of a rank-3 field

    Antiretroviral therapy to prevent HIV acquisition in serodiscordant couples in a hyperendemic community in rural South Africa

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    Background. Antiretroviral therapy (ART) was highly efficacious in preventing human immunodeficiency virus (HIV) transmission in stable serodiscordant couples in the HPTN-052 study, a resource-intensive randomized controlled trial with near-perfect ART adherence and mutual HIV status disclosure among all participating couples. However, minimal evidence exists of the effectiveness of ART in preventing HIV acquisition in stable serodiscordant couples in "real-life" population-based settings in hyperendemic communities of sub-Saharan Africa, where health systems are typically resource-poor and overburdened, adherence to ART is often low, and partners commonly do not disclose their HIV status to each other. Methods. Data arose from a population-based open cohort in KwaZulu-Natal, South Africa. A total of 17 016 HIV-uninfected individuals present between January 2005 and December 2013 were included. Interval-censored time-updated proportional hazards regression was used to assess how the ART status affected HIV transmission risk in stable serodiscordant relationships. Results. We observed 1619 HIV seroconversions in 17 016 individuals, over 60 349 person-years follow-up time. During the follow-up period, 1846 individuals had an HIV-uninfected and 196 had an HIV-infected stable partner HIV incidence was 3.8/100 person-years (PY) among individuals with an HIV-infected partner (95% confidence interval [CI], 2.3-5.6), 1.4/100 PY (.4-3.5) among those with HIV-infected partners receiving ART, and 5.6/100 PY (3.5-8.4) among those with HIV-infected partners not receiving ART. Use of ART was associated with a 77% decrease in HIV acquisition risk among serodiscordant couples (adjusted hazard ratio, 0.23; 95% CI,. 07-.80). Conclusions. ART initiation was associated with a very large reduction in HIV acquisition in serodiscordant couples in rural KwaZulu-Natal. However, this "real-life" effect was substantially lower than the effect observed in the HPTN-052 trial. To eliminate HIV transmission in serodiscordant couples, additional prevention interventions are probably needed

    Serial testing with an interferon-γ release assay in German healthcare workers

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    Aim: Data concerning conversion and reversion rates in the serial testing of healthcare workers (HCWs) is rare. So far, there is no consensus on how to define and interpret interferon-gamma release assays (IGRA) conversions and reversions, or how to deal with such results. We analysed conversion and reversion rates in the serial testing of HCWs using an IGRA

    Prevalence and correlates of adolescent self-injurious thoughts and behaviors: A population-based study in Burkina Faso

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    Self-injurious thoughts and behaviors (SITBs) are a growing concern among youth in sub-Saharan Africa, but their prevalence and correlates in this region are poorly understood. We therefore examined self-reported SITBs in a population-representative sample of youth in rural Burkina Faso. We used interviews from 1,538 adolescents aged 12 to 20 years living in 10 villages and 1 town in northwestern Burkina Faso. Adolescents were asked about their experiences with suicidal and nonsuicidal SITBs, adverse environmental factors, psychiatric symptoms, and interpersonal-social experiences. SITBs included lifetime prevalence of life is not worth living, passive suicide ideation, active suicide ideation, and nonsuicidal self-injury (NSSI). After describing SITB prevalence, we ran logistic and negative binomial regression models to predict SITBs. Weighted lifetime SITB prevalence estimates were: 15.6% (95% confidence interval [CI]: 13.7-18.0) for NSSI; 15.1% (95% CI: [13.2, 17.0]) for life is not worth living; 5.0% (95% CI [3.9, 6.0]) for passive suicide ideation; and 2.3% (95% CI [1.6, 3.0]) for active suicide ideation. Prevalence of life is not worth living increased with age. All four SITBs were significantly positively associated with mental health symptoms (depression symptoms, probable posttraumatic stress disorder) and interpersonal-social experiences (peer and social connectedness, physical assault, sexual assault and unwanted sexual experiences). Females were significantly more likely to report that their life was not worth living compared to males (aOR = 0.68; 95% CI [0.48, 0.96]). There is a high prevalence of SITBs among youth in rural Burkina Faso, most notably NSSI and life is not worth living, with interpersonal-social factors being the strongest predictors. Our results highlight the need for longitudinal SITB assessment to understand how risk for SITBs operates in resource-constrained settings, and to design interventions to mitigate risk. Given low school enrollment in rural Burkina Faso, it will be important to consider youth suicide prevention and mental health initiatives that are not school-based

    Effect of HIV self-testing on the number of sexual partners among female sex workers in Zambia: A randomized controlled trial

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    Objectives: To assess the effect of two health system approaches to distribute HIV selftests on the number of female sex workers’ client and nonclient sexual partners. Design: Cluster randomized controlled trial. Methods: Peer educators recruited 965 participants. Peer educator–participant groups were randomized 1 : 1 : 1 to one of three arms: delivery of HIV self-tests directly from a peer educator, free facility-based delivery of HIV self-tests in exchange for coupons, or referral to standard-of-care HIV testing. Participants in all three arms completed four peer educator intervention sessions, which included counseling and condom distribution. Participants were asked the average number of client partners they had per night at baseline, 1 and 4 months, and the number of nonclient partners they had in the past 12 months (at baseline) and in the past month (at 1 month and 4 months). Results: At 4 months, participants reported significantly fewer clients per night in the direct delivery arm (mean difference 0.78 clients, 95% CI 1.28 to 0.28, P ¼ 0.002) and the coupon arm (0.71, 95% CI 1.21 to 0.21, P ¼ 0.005) compared with standard of care. Similarly, they reported fewer nonclient partners in the direct delivery arm (3.19, 95% CI 5.18 to 1.21, P ¼ 0.002) and in the coupon arm (1.84, 95% CI 3.81 to 0.14, P ¼ 0.07) arm compared with standard of care. Conclusion: Expansion of HIV self-testing may have positive behavioral effects enhancing other HIV prevention efforts among female sex workers in Zambia. Trial Registration: ClinicalTrials.gov NCT02827240. Copyrigh

    Clinical outcomes and cost-effectiveness of COVID-19 vaccination in South Africa

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    Low- and middle-income countries are implementing COVID-19 vaccination strategies in light of varying vaccine efficacies and costs, supply shortages, and resource constraints. Here, we use a microsimulation model to evaluate clinical outcomes and cost-effectiveness of a COVID-19 vaccination program in South Africa. We varied vaccination coverage, pace, acceptance, effectiveness, and cost as well as epidemic dynamics. Providing vaccines to at least 40% of the population and prioritizing vaccine rollout prevented >9 million infections and >73,000 deaths and reduced costs due to fewer hospitalizations. Model results were most sensitive to assumptions about epidemic growth and prevalence of prior immunity to SARS-CoV-2, though the vaccination program still provided high value and decreased both deaths and health care costs across a wide range of assumptions. Vaccination program implementation factors, including prompt procurement, distribution, and rollout, are likely more influential than characteristics of the vaccine itself in maximizing public health benefits and economic efficiency

    Pendataan Jumlah Penduduk, Bangunan dan Usaha di Kelurahan Rufei Sorong

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    Kelurahan Rufei sendiri merupakan kelurahan yang memiliki tingkat kepadatan penduduk cukup besar dimana sebagian besar penduduk terutama masyarakat yang baru tinggal banyak yang belum terdaftar/terdata di kelurahan. Berdasarkan data hasil interview dengan Kepala Kelurahan Rufei pendataan penduduk di kelurahan ini khususnya di RW 03 belum dilakukan secara optimal. Program yang akan dilakukan dalam kegiatan pengabdian ini adalah membantu pihak kelurahan untuk melakukan pendataan penduduk khususnya di wilayah RW 3 yang memiliki 4 RT. Pendataan yang akan dilakukan terbagi menjadi 3 (tiga) bidang yaitu bidang kependudukan, bidang bangunan, dan bidang usaha. Hasil dari program pengabdian ini diperoleh data bahwa RW 03 memiliki jumlah penduduk laki-lakinya hampir sama dengan penduduk perempuan, dimana dalam keluarga memiliki rata-rata Anggota Rumah Tangga (ART) sekitar 4-5 orang. Masyarakat yang ada pada kelurahan Rufei khususnya RW 03 juga kebanyakan penduduknya non Papua dibanding Papua. Bangunan terbanyak yang ada di RW ini adalah bangunan permanen, dimana bangunan yang ada sebagian besar adalah milik sendiri. Ada juga masyarakat yang tinggal di RW ini hanya sewa, dan tidak menetap secara permanen. Masyarakat yang memiliki usaha di RW ini kebanyakan tidak memiliki ijin usaha, hal ini dikarenakan usaha yang ada hanya usaha Mikro. Usaha yang memiliki ijin usaha adalah usaha yang sudah termasuk dalam usaha menengah keatas

    Frailty and physical performance in the context of extreme poverty: a population-based study of older adults in rural Burkina Faso [version 1; peer review: 2 approved]

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    Background: Little is known about the prevalence of frailty and about normal values for physical performance among older individuals in low-income countries, in particular those in sub-Saharan Africa. We describe the prevalence of phenotypic frailty, and values and correlates of several physical performance measures in a cohort of middle-aged and older people living in rural Burkina Faso, one of the world’s poorest communities. Methods: We analysed data collected from participants aged over 40 in Nouna district, Burkina Faso. We measured handgrip strength, four metre walk speed, chair rise time, and derived the Fried frailty score based on grip strength, gait speed, body mass index, self-reported exhaustion, and physical activity. Frailty and physical performance indicators were then correlated with health and sociodemographic variables including comorbid disease, marital status, age, sex, wealth and activity impairment. Results: Our sample included 2973 individuals (1503 women), mean age 54 years. 1207 (43%) were categorised as non-frail, 1324 (44%) as prefrail, 212 (7%) as frail, and 167 (6%) were unable to complete all five frailty score components. Lower grip strength, longer chair stand time, lower walk speed and prevalence of frailty rose with age. Frailty was more common in women than men (8% vs 6%, p=0.01) except in those aged 80 and over. Frailty was strongly associated with impairment of activities of daily living and with lower wealth, being widowed, diabetes mellitus, hypertension, and self-reported diagnoses of tuberculosis or heart disease. With the exception of grip strength, which was higher in women than prior international normative values, women had greater deficits than men in physical performance. Conclusions: Phenotypic frailty and impaired physical performance were associated as expected with female sex, co-morbidities, increasing age and impaired activities of daily living. These results support the use of frailty measurements for classification of ageing related syndromes in this setting

    Decaying Hidden Dark Matter in Warped Compactification

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    The recent PAMELA and ATIC/Fermi/HESS experiments have observed an excess of electrons and positrons, but not anti-protons, in the high energy cosmic rays. To explain this result, we construct a decaying hidden dark matter model in string theory compactification that incorporates the following two ingredients, the hidden dark matter scenario in warped compactification and the phenomenological proposal of hidden light particles that decay to the Standard Model. In this model, on higher dimensional warped branes, various warped Kaluza-Klein particles and the zero-mode of gauge field play roles of the hidden dark matter or mediators to the Standard Model.Comment: 15 pages; v4, several clarifications added, update on Fermi/HESS result
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