2,588 research outputs found

    A systematic review of tuberculosis detection and prevention studies in prisons

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    Many studies have demonstrated that prisons are hotspots of tuberculosis disease and transmission. Despite this, it remains unclear which interventions are most effective at controlling tuberculosis in prisons. The objective was to determine the study designs used to investigate tuberculosis control in prisons, and the efficacy of interventions undertaken. This systematic review included published studies which had the aim of reducing TB incidence or prevalence, or increasing the number of people screened for active pulmonary tuberculosis in incarcerated populations. 2,429 records were identified, 178 full-text articles were screened, and 17 studies included. The majority of reports were before/after or prospective non-comparative studies. The median study duration was 23 months (range 5-144). The most common intervention was the introduction of active case finding (10/17 studies) but the timing and methods varied. Comparable pre- and post intervention outcome values were infrequently reported; therefore, it was not possible to quantify the efficacy of interventions. Data from studies of tuberculosis control in prisons is limited by a lack of: controlled interventions, reporting of pre-intervention methods, and comparable pre- and post-intervention outcomes. Prospective comparative trials of adequate duration to determine trends in incidence are necessary to understand which interventions are effective in prisons

    WZ Cygni: a Marginal Contact Binary in a Triple System?

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    We present new multiband CCD photometry for WZ Cyg made on 22 nights in two observing seasons of 2007 and 2008. Our light-curve synthesis indicates that the system is in poor thermal contact with a fill-out factor of 4.8% and a temperature difference of 1447 K. Including our 40 timing measurements, a total of 371 times of minimum light spanning more than 112 yr were used for a period study. Detailed analysis of the OO--CC diagram showed that the orbital period has varied by a combination with an upward parabola and a sinusoid. The upward parabola means the continuous period increase and indicates that some stellar masses are thermally transferred from the less to the more massive primary star at a rate of about 5.80×108\times10^{-8} M_\odot yr1^{-1}. The sinusoidal variation with a period of 47.9 yr and a semi-amplitude of 0.008 d can be interpreted most likely as the light-travel-time effect due to the existence of a low-mass M-type tertiary companion with a projected mass of M3sini3M_3 \sin i_3=0.26 M_\odot. We examined the evolutionary status of WZ Cyg from the absolute dimensions of the eclipsing pair. It belongs to the marginal contact binary systems before broken-contact phase, consisting of a massive primary star with spectral type of F4 and a secondary with the type K1.Comment: 20 pages, including 3 figures and 6 tables, accepted for publication in A

    A pulse of meteoric subsurface fluid discharging into the Chukchi Sea during the Early Holocene Thermal Maximum (EHTM)

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    This work was supported bythe Korea Ministry of Science and ICT (GP2020-038), by the Korea Ministry of Oceans and Fisheries (NP2011-040 and 1525011795), and by the Korea Polar Research Institute (Grants No. PE20350). W.-L.H. acknowledges the supports from the ArcticSGD, a project supported by the Norway Grants and the EEA Grants (2019/34/H/ST10/00645). Additional funds were contributed by the AWI Research Program PACES-II Workpackage 3.1 and 3.2.The response of Arctic Ocean biogeochemistry to subsurface flow driven by permafrost thaw is poorly understood. We present dissolved chloride and water isotopic data from the Chukchi Sea Shelf sediments that reveal the presence of a meteoric subsurface flow enriched in cations with a radiogenic Sr fingerprint. This subsurface fluid is also enriched in dissolved inorganic carbon and methane that bear isotopic compositions indicative of a carbon reservoir modified by reactions in a closed system. Such fluid characteristics are in stark contrast with those from other sites in the Chukchi Sea where the pore water composition shows no sign of meteoric input, but reflect typical biogeochemical reactions associated with early diagenetic sequences in marine sediment. The most likely source of the observed subsurface flow at the Chukchi Sea Shelf is from the degradation of permafrost that had extended to the shelf region during the Last Glacial Maximum. Our data suggest that the permafrost-driven subsurface flow most likely took place during the 2-3 oC warming in the Early Holocene Thermal Maximum (EHTM). This time scale is supported by numerical simulation of pore fluid profiles, which indicate that a minimum of several thousand years must have passed since the cessation of the subsurface methane-bearing fluid flow.Publisher PDFPeer reviewe

    Coinfection of Viral Agents in Korean Children with Acute Watery Diarrhea

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    Currently, there are a few reports on viral coinfection that causes an acute watery diarrhea in Korean children. So, to evaluate the features of coinfectious viral agents in children with acute watery diarrhea, we enrolled 155 children with acute watery diarrhea from July 2005 to June 2006. Fecal samples were collected and evaluated for various viral infections such as rotavirus, norovirus, adenovirus and astrovirus. The mean (±standard deviation) age of the children was 2.71±2.37 yr. The detection rate of viral agents was most common in children between the ages of 1 and 3 yr. Rotavirus was detected in 63 children (41.3%), norovirus in 56 (36.2%), adenovirus in 11 (7.1%), and astrovirus in 1 (0.6%). Regarding rotavirus, there were 38 (60.3%) cases with monoinfection and 25 (39.7%) with coinfection. For norovirus, there were 33 (58.9%) cases with monoinfection and 23 (41.1%) with coinfection. Coinfection with rotavirus and norovirus was most common, and occurred in 20/155 cases (12.9%) including coinfection with adenovirus. So, rotavirus and norovirus were the most common coinfectious viral agents in our study population with acute watery diarrhea

    The Algol System SZ Herculis: Physical Nature and Orbital Behavior

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    Multiband CCD photometric observations of SZ Her were obtained between 2008 February and May. The light curve was completely covered and indicated a significant temperature difference between both components. The light-curve synthesis presented in this paper indicates that the eclipsing binary is a classical Algol-type system with parameters of qq=0.472, ii=87^\circ.57, and Δ\Delta(T1T_{1}--T2T_{2})=2,381 K; the primary component fills approximately 77% of its limiting lobe and is slightly larger than the lobe-filling secondary. More than 1,100 times of minimum light spanning more than one century were used to study an orbital behavior of the binary system. It was found that the orbital period of SZ Her has varied due to a combination of two periodic variations with cycle lengths of P3P_3=85.8 yr and P4P_4=42.5 yr and semi-amplitudes of K3K_3=0.013 d and K4K_4=0.007 d, respectively. The most reasonable explanation for them is a pair of light-time effects (LITEs) driven by the possible existence of two M-type companions with minimum masses of M3M_3=0.22 M_\odot and M4M_4=0.19 M_\odot, that are located close to the 2:1 mean motion resonance. If two additional bodies exist, then the overall dynamics of the multiple system may provide a significant clue to the formation and evolution of the eclipsing pair.Comment: 23 pages, including 5 figures and 7 tables, accepted for publication in A

    Comparative Microsatellite Typing of New World Leishmania infantum Reveals Low Heterogeneity among Populations and Its Recent Old World Origin

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    Leishmania infantum (syn. L. chagasi) is the causative agent of visceral leishmaniasis (VL) in the New World (NW) with endemic regions extending from southern USA to northern Argentina. The two hypotheses about the origin of VL in the NW suggest (1) recent importation of L. infantum from the Old World (OW), or (2) an indigenous origin and a distinct taxonomic rank for the NW parasite. Multilocus microsatellite typing was applied in a survey of 98 L. infantum isolates from different NW foci. The microsatellite profiles obtained were compared to those of 308 L. infantum and 20 L. donovani strains from OW countries previously assigned to well-defined populations. Two main populations were identified for both NW and OW L. infantum. Most of the NW strains belonged to population 1, which corresponded to the OW MON-1 population. However, the NW population was much more homogeneous. A second, more heterogeneous, population comprised most Caribbean strains and corresponded to the OW non-MON-1 population. All Brazilian L. infantum strains belonged to population 1, although they represented 61% of the sample and originated from 9 states. Population analysis including the OW L. infantum populations indicated that the NW strains were more similar to MON-1 and non-MON-1 sub-populations of L. infantum from southwest Europe, than to any other OW sub-population. Moreover, similarity between NW and Southwest European L. infantum was higher than between OW L. infantum from distinct parts of the Mediterranean region, Middle East and Central Asia. No correlation was found between NW L. infantum genotypes and clinical picture or host background. This study represents the first continent-wide analysis of NW L. infantum population structure. It confirmed that the agent of VL in the NW is L. infantum and that the parasite has been recently imported multiple times to the NW from southwest Europe

    Dynamical Boson Stars

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    The idea of stable, localized bundles of energy has strong appeal as a model for particles. In the 1950s John Wheeler envisioned such bundles as smooth configurations of electromagnetic energy that he called {\em geons}, but none were found. Instead, particle-like solutions were found in the late 1960s with the addition of a scalar field, and these were given the name {\em boson stars}. Since then, boson stars find use in a wide variety of models as sources of dark matter, as black hole mimickers, in simple models of binary systems, and as a tool in finding black holes in higher dimensions with only a single killing vector. We discuss important varieties of boson stars, their dynamic properties, and some of their uses, concentrating on recent efforts.Comment: 79 pages, 25 figures, invited review for Living Reviews in Relativity; major revision in 201
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