420 research outputs found

    First Detection of Cosmic Microwave Background Lensing and Lyman-{\alpha} Forest Bispectrum

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    We present the first detection of a correlation between the Lyman-α\alpha forest and cosmic microwave background (CMB) lensing. For each Lyman-α\alpha forest in SDSS-III/BOSS DR12, we correlate the one-dimensional power spectrum with the CMB lensing convergence on the same line of sight from Planck. This measurement constitutes a position-dependent power spectrum, or a squeezed bispectrum, and quantifies the non-linear response of the Lyman-α\alpha forest power spectrum to a large-scale overdensity. The signal is measured at 5~σ\sigma and is consistent with the Λ\LambdaCDM expectation. We measure the linear bias of the Lyman-α\alpha forest with respect to the dark matter distribution, and constrain a combination of non-linear terms including the non-linear bias. This new observable provides a consistency check for the Lyman-α\alpha forest as a large-scale structure probe and tests our understanding of the relation between intergalactic gas and dark matter. In the future, it could be used to test hydrodynamical simulations and calibrate the relation between the Lyman-α\alpha forest and dark matter.Comment: 8 pages, 7 figures; accepted for publication in Phys. Rev.

    The origin and prevention of pandemics.

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    Despite the fact that most emerging diseases stem from the transmission of pathogenic agents from animals to humans, the factors that mediate this process are still ill defined. What is known, however, is that the interface between humans and animals is of paramount importance in the process. This review will discuss the importance of the human-animal interface to the disease emergence process. We also provide an overview of factors that are believed to contribute to the origin and global spread of emerging infectious diseases and offer suggestions that may serve as future prevention strategies, such as social mobilization, public health education, behavioral change, and communication strategies. Because there exists no comprehensive global surveillance system to monitor zoonotic disease emergence, the intervention measures discussed herein may prove effective temporary alternatives

    Enhancement of the electronic contribution to the low temperature specific heat of Fe/Cr magnetic multilayer

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    We measured the low temperature specific heat of a sputtered (Fe23A˚/Cr12A˚)33(Fe_{23\AA}/Cr_{12\AA})_{33} magnetic multilayer, as well as separate 1000A˚1000\AA thick Fe and Cr films. Magnetoresistance and magnetization measurements on the multilayer demonstrated antiparallel coupling between the Fe layers. Using microcalorimeters made in our group, we measured the specific heat for 4<T<30K4<T<30 K and in magnetic fields up to 8T8 T for the multilayer. The low temperature electronic specific heat coefficient of the multilayer in the temperature range 4<T<14K4<T<14 K is γML=8.4mJ/K2g−at\gamma_{ML}=8.4 mJ/K^{2}g-at. This is significantly larger than that measured for the Fe or Cr films (5.4 and 3.5mJ/K2mol3.5 mJ/K^{2}mol respectively). No magnetic field dependence of γML\gamma_{ML} was observed up to 8T8 T. These results can be explained by a softening of the phonon modes observed in the same data and the presence of an Fe-Cr alloy phase at the interfaces.Comment: 20 pages, 5 figure

    The distribution of biodiversity richness in the tropics

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    We compare the numbers of vascular plant species in the three major tropical areas. The Afrotropical Region (Africa south of the Sahara Desert plus Madagascar), roughly equal in size to the Latin American Region (Mexico southward), has only 56,451 recorded species (about 170 being added annually), as compared with 118,308 recorded species (about 750 being added annually) in Latin America. Southeast Asia, only a quarter the size of the other two tropical areas, has approximately 50,000 recorded species, with an average of 364 being added annually. Thus, Tropical Asia is likely to be proportionately richest in plant diversity, and for biodiversity in general, for its size. In the animal groups we reviewed, the patterns of species diversity were mostly similar except for mammals and butterflies. Judged from these relationships, Latin America may be home to at least a third of global biodiversity

    Pressure Measurements Using an Airborne Differential Absorption Lidar

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    Remote airborne measurements of the vertical and horizontal structure of the atmospheric pressure field in the lower troposphere are made with an oxygen differential absorption lidar (DIAL). A detailed analysis of this measurement technique is provided which includes corrections for imprecise knowledge of the detector background level, the oxygen absorption fine parameters, and variations in the laser output energy. In addition, we analyze other possible sources of systematic errors including spectral effects related to aerosol and molecular scattering interference by rotational Raman scattering and interference by isotopic oxygen fines

    Abstracts reporting of HIV/AIDS randomized controlled trials in general medicine and infectious diseases journals: completeness to date and improvement in the quality since CONSORT extension for abstracts

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    Abstract Background Sufficiently detailed abstracts of randomized controlled trials (RCTs) are important, because readers often base their assessment of a trial solely on information in the abstract. We aimed at comparing reporting quality of RCTs in HIV/AIDS medicine before and after the publication of the 2008 CONSORT extension for abstracts and to investigate factors associated with better reporting quality. Methods We searched PubMed/Medline for HIV/AIDS RCTs published between 2006–07 (Pre-CONSORT) and 2014–15 (Post-CONSORT) in 40 leading general medicine and infectious diseases journals. Two investigators extracted data and scored abstracts. The primary outcome was the adjusted mean number of items reported among the 17 required. Proportions of abstracts reporting each of 17 items were considered as secondary outcome. The adjustment was done for journal field, CONSORT endorsement, abstract format, type of intervention, journal impact factor and authorship. This study received no funding. Results The adjusted mean number of reported items was 7.2 (95 % CI 6.6–7.7) in pre-CONSORT (n = 159) and 7.8 (95 % confidence interval [CI] 7.3–8.4) in post-CONSORT (n = 153) (mean difference 0.7; 95 % CI 0.1–1.2). Journal high impact factor (adjusted incidence rate ratio 2.16; 95 % CI 1.83–2.54), abstract with 13 authors or more (1.39; 95 % CI 1.07–1.79) and non-pharmacological intervention (1.19; 95 % CI 1.03–1.37) were independent factors for better reporting quality. There were significant improvements in reporting on participants, randomization, outcome results, registration and funding; regression for author contact; and no change for other items: title, design, interventions, objective, primary outcome, blinding, number randomized, recruitment, number analyzed, harms and conclusions. Conclusions After the publication of the CONSORT extension for abstracts, the reporting quality of HIV/AIDS RCT abstracts in general medicine and infectious diseases journals has suboptimally improved. Thus, stricter adherence to the CONSORT for abstract are needed to improve the reporting quality of HIV/AIDS RCT abstracts

    Prevalence of Gestational Diabetes in Hospitals in the City of Lubumbashi in the Democratic Republic of Congo: Case of the Jason Sendwe General Reference Hospital in 2015 to 2019

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    Gestational diabetes is defined as a carbohydrate tolerance disorder leading to hyperglycaemia of varying severity, occurring or first diagnosed during pregnancy, regardless of the treatment required and the course of the postpartum period. Its prevalence has been estimated at between 2.2% and 8.8% of pregnancies, depending on the populations studied and the screening criteria used. We determined the prevalence of gestational diabetes at the Jason Sendwe General Referral Hospital. A descriptive cross-sectional study was carried out from January 2015 to December 2019 at Sendwe Hospital. It concerned 48 pregnant women from 24 weeks of pregnancy. The diagnosis of gestational diabetes was made by blood glucose obtained with the O'Sullivan test or by fasting blood glucose. The prevalence of gestational diabetes was 2.15%. Modifiable and non-modifiable factors associated with gestational diabetes in this study are age ≥ 35 years, parity, history of macrosomia, and history of type 2 diabetes in the surrogates of the pregnancies. The prevalence rate remains high and shows that gestational diabetes is a public health problem in the city of Lubumbashi. The O'Sullivan test is a valid alternative for its good detection. We found that age, especially after 35 years is the major determinant of gestational diabetes in the population living in Lubumbashi

    A study of the significance of photoparoxysmal responses and spontaneous epileptiform discharges in the EEG in childhood epilepsy

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    Aim: In clinical practice, there is a prevailing notion that photosensitivity mostly occurs in children with epilepsy (CWE) with idiopathic generalized epilepsy. We investigated the distribution of epilepsy types and etiology in photosensitive children and the associations with specific clinical and electroencephalogram (EEG) variables. Methods: In this retrospective cohort study, clinical data were acquired from all children that showed photosensitivity during systematic intermittent photic stimulation (IPS), over a 10-year interval at a tertiary level Children\u27s Hospital, Winnipeg. Patient demographics, EEG findings, and clinical data and symptoms during IPS were abstracted. Classification of diagnoses using the International League Against Epilepsy (ILAE) 2017 guidelines was done by an expert panel. Results: Seventy-eight photosensitive children were identified. Forty (51.3%) had generalized epilepsy (idiopathic: 27, structural: 2, other: 11) compared with 19 (24.4%) focal (idiopathic: 1, structural: 2, other: 16), 8 (10.3%) combined focal and generalized (structural: 4, other: 4), and 11 (14.1%) unknown epilepsy (other: 11); (χ2 (3) = 32.1, p = .000). Self-sustaining or outlasting photoparoxysmal responses (PPRs) occurred in association with all epilepsy types; however, the EEGs of focal CWE without treatment comprised almost solely of PPRs which outlasted the stimulus (8/10), in contrast to only 8/17 of focal CWE with treatment and to 13/26 of generalized epilepsy without treatment. Most frequency intervals in individual patients were less under treatment: a decrease in standardized photosensitivity range (SPR) was seen in 5 CWE, an increase in 2, and no change in 1 during treatment. Both CWE with focal and generalized epilepsy showed abnormal activity on EEG during hyperventilation (40% vs 65.7%). Thirteen out of 14 CWE with clinical signs during IPS had independent spontaneous epileptiform discharges (SEDs) in the EEG recording. Conclusion: Photosensitivity occurs in all types of epilepsy rather than in idiopathic generalized epilepsy alone. Surprisingly, there is a tendency for focal epilepsy to be associated with self-sustaining PPRs, especially when no treatment is used. Treatment tends to make the PPR more self-limiting and decrease the SPR. There is a tendency that clinical signs during IPS occur in EEGs in individuals with SEDs

    Determinants of occurrence of chronic hypertension in patients who had preeclampsia at the Yaoundé central hospital

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    Background: Preeclampsia is an abnormal elevation of blood pressure with systolic blood pressure ≥140 mmHg, and/or diastolic blood pressure ≥90 mmHg associated with proteinuria in a pregnant woman beyond 20 weeks of gestation. This generally disappears postpartum. Some women, however, will later on develop chronic hypertension. Our objective was to assess the determinants of occurrence of chronic hypertension in patients who had preeclampsia at the Yaoundé Central Hospital. Methods: we carried out a retrospective case-control study over ten years from January 2012 to December 2022. The cases consisted of women who developed chronic hypertension within 5 years following an episode of preeclampsia in pregnancy. These were matched with two controls each; women who had not developed chronic hypertension following preeclampsia in pregnancy. Results: We recruited 60 cases and 120 controls. After bivariate analysis, the sociodemographic factors seemingly associated with the occurrence of chronic hypertension were; age between 25-35 years p=0.01; OR=2.9 (1.5-5.5), the profession of pupil/student; p=0.05; OR=0.3 (0.12-0.7). The clinical factors found were multigravidas; OR=3.1 (1.6-5.9); p=0.00, as well as pauciparous women; OR=2.1 (1.1-4.4); p=0.03, family history of hypertension; OR=2.5 (1.3-4.8); p=0.04 and BMI greater than 40 kg/m2; OR=3.8 (1.0-13.6); p=0.02. After logistic regression, the factor independently associated with the occurrence of chronic hypertension is a family history of hypertension; p=0.01; OR=2.45 (1.18-4.96). Conclusions: A family history of hypertension is a major risk factor for the occurrence of chronic hypertension in patients who have had preeclampsia
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