178 research outputs found

    Cepheid Calibration of the Peak Brightness of SNe Ia -- IX. SN 1989B in NGC 3627

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    (Abridged) Repeated imaging observations have been made of NGC 3627 with the HST in 1997/98, over an interval of 58 days. Images were obtained on 12 epochs in the F555W band and on five epochs in the F814W band. The galaxy hosted the prototypical, `Branch normal', type Ia supernova SN 1989B. A total of 83 variables have been found, of which 68 are definite Cepheid variables with periods ranging from 75 days to 3.85 days. The de-reddened distance modulus is determined to be (m-M)_0= 30.22+/-0.12 (internal uncertainty) using a subset of the Cepheid data whose reddening and error parameters are secure. The photometric data of Wells et al. (1994), combined with the Cepheid data for NGC 3627 give M_B(max)= -19.36+/-0.18 and M_V(max)= -19.34+/-0.16 for SN 1989B. Combined with the previous six calibrations in this program, plus two additional calibrations determined by others gives the mean absolute magnitudes at maximum of = -19.48+/-0.07 and = -19.48 +/-0.07 for `Branch normal' SNe Ia at this interim stage in the calibration program. The second parameter correlations of M(max) of blue SNe Ia with decay rate, color at maximum, and Hubble type are re-investigated. The dependence of on decay rate is non-linear, showing a minimum for decay rates between 1.0< Delta m_15 <1.6. Magnitudes corrected for decay rate show no dependence on Hubble type, but a dependence on color remains. Correcting both the fiducial sample of 34 SNe Ia with decay-rate data and the current 8 calibrating SNe Ia for the correlation with decay rate as well as color gives H_0= 60+/-2 (internal) km/s/Mpc, in both B and V. The same value to within 4% is obtained if only the SNe Ia in spirals (without second parameter corrections) are considered.Comment: 32 pages (with 7 tables and 14 figures) LaTeX, uses emulateapj.sty; a full-resolution version with complete figs. 4 and 5 is available at http://www.astro.unibas.ch/cosmology/papers.html ; accepted for publication in Ap

    Cepheid Calibration of the Peak Brightness of SNe Ia. X. SN 1991T in NGC 4527

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    Repeated imaging observations have been made of NGC 4527 with the Hubble Space Telescope between April and June 1999, over an interval of 69 days. Images were obtained on 12 epochs in the F555W band and on five epochs in the F814W band. The galaxy hosted the type Ia supernova SN1991T, which showed relatively unusual behavior by having both an abnormal spectrum near light maximum, and a slower declining light curve than the proto-typical Branch normal SNe Ia. A total of 86 variables that are putative Cepheids have been found, with periods ranging from 7.4 days to over 70 days. From photometry with the DoPHOT program, the de-reddened distance modulus is determined to be (m-M)_0 = 30.67 +/- 0.12 (internal uncertainty) using a subset of the Cepheid data whose reddening and error parameters are secure. A parallel analysis of the Cepheids using photometry with ROMAFOT yields (m -M)_0 =30.82 +/- 0.11. The final adopted modulus is (m -M)_0 =30.74 +/- 0.12 +/- 0.12 (d=14.1 +/- 0.8 +/- 0.8 Mpc). The photometric data for SN1991T are used in combination with the Cepheid distance to NGC 4527 to obtain the absolute magnitude for this supernova of M_V^0(max) = -19.85 +/- 0.29. The relatively large uncertainty is a result of the range in estimates of the reddening to the supernova. Thus SN1991T is seen to be only moderately brighter (by ~ 0.3 mag) than the mean for spectroscopically normal supernovae, although magnitude differences of up to 0.6 mag cannot be ruled out.Comment: 46 pages, LATEX using aaspp4.sty, including 9 embedded tables, 19 figures (gif and jpg files), a full-resolution version (ps files) is available at http://www.astro.unibas.ch/forschung/ll/cepheid.shtml, accepted for publication in the Astrophysical Journa

    A Cepheid Distance to NGC 4603 in Centaurus

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    In an attempt to use Cepheid variables to determine the distance to the Centaurus cluster, we have obtained images of NGC 4603 with the Hubble Space Telescope on 9 epochs using WFPC2 and the F555W and F814W filters. This galaxy has been suggested to lie within the ``Cen30'' portion of the cluster and is the most distant object for which this method has been attempted. Previous distance estimates for Cen30 have varied significantly and some have presented disagreements with the peculiar velocity predicted from redshift surveys, motivating this investigation. Using our observations, we have found 61 candidate Cepheid variable stars; however, a significant fraction of these candidates are likely to be nonvariable stars whose magnitude measurement errors happen to fit a Cepheid light curve of significant amplitude for some choice of period and phase. Through a maximum likelihood technique, we determine that we have observed 43 +/- 7 real Cepheids and that NGC 4603 has a distance modulus of 32.61 +0.11/-0.10 (random, 1 sigma) +0.24/-0.25 (systematic, adding in quadrature), corresponding to a distance of 33.3 Mpc. This is consistent with a number of recent estimates of the distance to NGC 4603 or Cen30 and implies a small peculiar velocity consistent with predictions from the IRAS 1.2 Jy redshift survey if the galaxy lies in the foreground of the cluster.Comment: Accepted for publication in the Astrophysical Journal. 17 pages with 17 embedded figures and 3 tables using emulateapj.sty. Additional figures and images may be obtained from http://astro.berkeley.edu/~marc/n4603

    A systematic review of primary care models for non-communicable disease interventions in Sub-Saharan Africa

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    Background Chronic diseases, primarily cardiovascular disease, respiratory disease, diabetes and cancer, are the leading cause of death and disability worldwide. In sub-Saharan Africa (SSA), where communicable disease prevalence still outweighs that of non-communicable disease (NCDs), rates of NCDs are rapidly rising and evidence for primary healthcare approaches for these emerging NCDs is needed. Methods A systematic review and evidence synthesis of primary care approaches for chronic disease in SSA. Quantitative and qualitative primary research studies were included that focused on priority NCDs interventions. The method used was best-fit framework synthesis. Results Three conceptual models of care for NCDs in low- and middle-income countries were identified and used to develop an a priori framework for the synthesis. The literature search for relevant primary research studies generated 3759 unique citations of which 12 satisfied the inclusion criteria. Eleven studies were quantitative and one used mixed methods. Three higher-level themes of screening, prevention and management of disease were derived. This synthesis permitted the development of a new evidence-based conceptual model of care for priority NCDs in SSA. Conclusions For this review there was a near-consensus that passive rather than active case-finding approaches are suitable in resource-poor settings. Modifying risk factors among existing patients through advice on diet and lifestyle was a common element of healthcare approaches. The priorities for disease management in primary care were identified as: availability of essential diagnostic tools and medications at local primary healthcare clinics and the use of standardized protocols for diagnosis, treatment, monitoring and referral to specialist care

    Same-day antiretroviral therapy initiation in people living with HIV who have tuberculosis symptoms: a systematic review

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    Objectives Tuberculosis symptoms are very common among people living with HIV (PLHIV) initiating antiretroviral therapy (ART), are not specific for tuberculosis disease and may result in delayed ART start. The risks and benefits of same-day ART initiation in PLHIV with tuberculosis symptoms are unknown. Methods We systematically reviewed nine databases on 12 March 2020 to identify studies that investigated same-day ART initiation among PLHIV with tuberculosis symptoms and reported both their approach to TB screening and clinical outcomes. We extracted and summarised data about TB screening, numbers of people starting same-day ART and outcomes. Results We included four studies. Two studies deferred ART for everyone with any tuberculosis symptoms (one or more of cough, fever, night sweats or weight loss) and substantial numbers of people had deferred ART start (28% and 39% did not start same-day ART). Two studies permitted some people with tuberculosis symptoms to start same-day ART, and fewer people deferred ART (2% and 16% did not start same-day). Two of the four studies were conducted sequentially; proven viral load suppression at eight months was 31% when everyone with tuberculosis symptoms had ART deferred, and 44% when algorithm was changed so that some people with tuberculosis symptoms could start same-day ART. Conclusions Although tuberculosissymptoms are very common in people starting ART, there is insufficient evidence about whether presence of tuberculosis symptoms should lead to ART start being deferred or not. Research to inform clear guidelines would help maximise benefits of sameday ART

    Serum 25-hydroxyvitamin D levels and intramuscular vitamin D3 supplementation among Eritrean migrants recently arrived in Switzerland.

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    In a cross-sectional screening programme, we assessed serum vitamin D levels in adult Eritrean refugees recently arrived in Switzerland. Median vitamin D level among 107 participants (95 males and 12 females) was 27 nmol/l (interquartile range 23-42 nmol/l), 86% had insufficient vitamin D levels (≤50 nmol/l) and 36% severe deficiency (<25 nmol/l). In 29 participants who received single-dose intramuscular vitamin D substitution (300 000 IU), median vitamin D levels increased from 25 to 35 nmol/l after 3 months (p = 0.005); only 11 (38%) reached sufficient vitamin D levels. Eritrean migrants should be routinely screened for vitamin D deficiency. Single-dose intramuscular supplementation appeared to be insufficient to achieve optimal levels in the majority of participants

    Head-to-head comparison of the WHO STEPwise approach with immediate unattended and delayed unattended automated blood pressure measurements during household-based screening: a diagnostic accuracy study in Lesotho

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    BACKGROUND: WHO introduced the STEPwise approach to surveillance (STEPS) to monitor trends in non-communicable diseases. For arterial hypertension, the STEPS protocol takes the average of the last two out of three standard blood pressure measurements (SBPM). This study assesses the diagnostic accuracy of SBPM, same-day and next-day unattended automated measurement (uABP), with 24 h ambulatory measurement (24 h-ABPM) as reference. METHODS: This diagnostic accuracy study was done within a population-based household survey on cardiovascular risk factors in two districts in Northern Lesotho. Adults (aged ≥ 18 years) with elevated SBPM (defined as ≥140/90 mmHg), and 2:1 age- and sex-matched participants with normal SBPM during the survey were recruited. Following SBPM, first uABP readings were obtained on survey day. Afterwards, participants received a 24 h-ABPM device. Second uABP readings were taken 24 h later, after retrieval of the 24 h-ABPM. The main outcome was overall diagnostic accuracy of all screening measurements (SBPM, first uABP, and second uABP), determined using area under the receiver operating characteristic curve (AUROC), with 24 h-ABPM as a reference. FINDINGS: Between November 2, 2021 and August 31, 2022, 275 participants (mean age 58 years (SD: 16 years), 163 (59%) female) were enrolled, 183 of whom had elevated and 92 had normal SBPM. Mean difference between systolic daytime 24 h-ABPM and screening measurements was highest for SBPM (mean difference: -13 mmHg; 95% CI: -14 to -11). Mean difference between diastolic daytime 24 h-ABPM and diastolic SBPM was -2 mmHg (95% CI: -4 to -1), whereas no difference was found for mean diastolic first uABP (mean difference: -1 mmHg; 95% CI: -2.0 to 0.3); and mean diastolic second uABP (mean difference: 1.0 mmHg; 95% CI: -0.4 to 2.3). White coat hypertension was highest with SBPM (55 [20%]), followed by first uABP (27 [9.8%]), and second uABP (18 [6.5%]). Using systolic daytime 24 h-ABPM as a reference, the uABPs had higher AUROC (first uABP: 87% [95% CI: 83-91]; second uABP: 88% [95% CI: 84-92]); SBPM: (79% [95% CI: 74-85]). This difference was significant between first uABP and SBPM (P = 0.0024), and between second uABP and SBPM (P = 0.0017). INTERPRETATION: uABP had better diagnostic performance than SBPM. Integration of uABP into STEPS protocol should be considered. FUNDING: Swiss Agency for Development and Cooperation under the ComBaCaL project, and the World Diabetes Foundation

    Task shifting to non-physician clinicians for integrated management of hypertension and diabetes in rural Cameroon: a programme assessment at two years

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    <p>Abstract</p> <p>Background</p> <p>The burden of non-communicable chronic diseases, such as hypertension and diabetes, increases in sub-Saharan Africa. However, the majority of the rural population does still not have access to adequate care. The objective of this study is to examine the effectiveness of integrating care for hypertension and type 2 diabetes by task shifting to non-physician clinician (NPC) facilities in eight rural health districts in Cameroon.</p> <p>Methods</p> <p>Of the 75 NPC facilities in the area, 69 (87%) received basic equipment and training in hypertension and diabetes care. Effectiveness was assessed after two years on status of equipment, knowledge among trained NPCs, number of newly detected patients, retention of patients under care, treatment cost to patients and changes in blood pressure (BP) and fasting plasma glucose (FPG) among treated patients.</p> <p>Results</p> <p>Two years into the programme, of 54 facilities (78%) available for re-assessment, all possessed a functional sphygmomanometer and stethoscope (65% at baseline); 96% stocked antihypertensive drugs (27% at baseline); 70% possessed a functional glucose meter and 72% stocked oral anti-diabetics (15% and 12% at baseline). NPCs' performance on multiple-choice questions of the knowledge-test was significantly improved. During a period of two years, trained NPCs initiated treatment for 796 patients with hypertension and/or diabetes. The retention of treated patients at one year was 18.1%. Hypertensive and diabetic patients paid a median monthly amount of 1.4 and 0.7 Euro respectively for their medication. Among hypertensive patients with ≥ 2 documented visits (n = 493), systolic BP decreased by 22.8 mmHg (95% CI: -20.6 to -24.9; p < 0.0001) and diastolic BP by 12.4 mmHg (-10.9 to -13.9; p < 0.0001). Among diabetic patients (n = 79) FPG decreased by 3.4 mmol/l (-2.3 to -4.5; p < 0.001).</p> <p>Conclusions</p> <p>The integration of hypertension and diabetes into primary health care of NPC facilities in rural Cameroon was feasible in terms of equipment and training, accessible in terms of treatment cost and showed promising BP- and FPG-trends. However, low case-detection rates per NPC and a very high attrition among patients enrolled into care, limited the effectiveness of the programme.</p

    CORS Baade-Wesselink distance to the LMC NGC 1866 blue populous cluster

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    We used Optical, Near Infrared photometry and radial velocity data for a sample of 11 Cepheids belonging to the young LMC blue populous cluster NGC 1866 to estimate their radii and distances on the basis of the CORS Baade-Wesselink method. This technique, based on an accurate calibration of the surface brightness as a function of (U-B), (V-K) colors, allows us to estimate, simultaneously, the linear radius and the angular diameter of Cepheid variables, and consequently to derive their distance. A rigorous error estimate on radius and distances was derived by using Monte Carlo simulations. Our analysis gives a distance modulus for NGC 1866 of 18.51+/-0.03 mag, which is in agreement with several independent results.Comment: 21 pages, 10 figures, Accepted for publication in the Astrophysical Journa

    Low agreement and frequent invalid controls in two SARS-CoV-2 T-cell assays in people with compromised immune function

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    T-cell response plays an important role in SARS-CoV-2 immunogenicity. For people living with HIV (PWH) and solid organ transplant (SOT) recipients there is limited evidence on the reliability of commercially available T-cell tests. We assessed 173 blood samples from 81 participants (62 samples from 35 PWH; 111 samples from 46 SOT recipients [lung and kidney]) with two commercial SARS-CoV-2 Interferon-γ (IFN-γ) release assays (IGRA; SARS-CoV-2 IGRA by Euroimmun, and IGRA SARS-CoV-2 by Roche). The reliability between the tests was judged as low (Cohen's kappa [κ] = 0.20; overall percent agreement [OPA] = 66%). A high proportion of tests were invalid (22% Euroimmun; 8% Roche). When excluding these invalid tests, the agreement was higher (κ  =  0.43; OPA = 90%). The low reliability between the two T-cell tests indicates that results should be interpreted with caution in SOT recipients and PWH and that SARS-CoV-2 T-cell tests need to be optimized and further validated for use in vulnerable patient populations
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