262 research outputs found
Cepheid Calibration of the Peak Brightness of SNe Ia -- IX. SN 1989B in NGC 3627
(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
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
Long-term outcome after SARS-CoV-2 infection in healthcare workers: a single centre cohort study
BACKGROUND: Long-term symptoms after acute COVID-19 are highly debated. Nevertheless, data on long-term symptoms of COVID-19 in healthcare workers are scarce. METHODS: We assessed frequency and risk factors of persisting symptoms in a retrospective cohort of healthcare workers infected with SARS-CoV-2. RESULTS: Persistent symptoms at 3 and 12 months were reported by 26.5% and 13.5% of participants, respectively. Most commonly reported symptoms were fatigue, impaired sense of taste or smell and general weakness. A history of depression or state of exhaustion, pre-existing lung disease and older age were associated with persisting symptoms. CONCLUSION: Our study shows that a relevant proportion of healthcare workers with mild COVID-19 report persisting symptoms over 3 and 12 months. Although in the majority of cases symptoms are mild, this study highlights the need for further research into causes and therapy
Mental health and resilience among Eritrean refugees at arrival and one-year post-registration in Switzerland: a cohort study
OBJECTIVE: Eritrea is the most frequent country of origin among asylum seekers in Switzerland. On their journey through the desert and across the Mediterranean Sea, Eritrea refugees are often exposed to traumatizing experiences. The aim of this study is to assess the mental health status and resilience of Eritrean migrants in Switzerland upon arrival and one-year post-arrival, using standardized mental health screening and resilience assessment tools. RESULTS: At baseline, 107 refugees (11.2% female, median age 25) were interviewed: 52 (48.6%) screened positive for Post-Traumatic Stress Disorder (score ≥ 30), 10.3% for anxiety (≥ 10) and 15.0% for depression (≥ 10); 17.8% scored as risk/hazardous drinkers (≥ 8). The majority (94.4%) had a high resilience score (≥ 65). For one-year follow-up, 48 asylum seekers could be reached. In interviews 18 (38%) of these reported imprisonment in a transit country and 28 (58%) that they had witnessed the death of a close person along the migration route. At the one year assessment, rates of risky/hazardous alcohol use remained unchanged, rates of positive PTSD screening tended to be lower (50.0% (24/48) at baseline vs 25.0% (12/48) at follow-up), as were rates of positive screening for anxiety (8.3% vs 4.2%) and depression (14.6 vs 6.3%)
Reaching absent and refusing individuals during home-based HIV testing through self-testing-at what cost?
Introduction: In the HOSENG trial (NCT03598686), the secondary distribution of oral self-tests for persons absent or refusing to test during a home-based HIV testing campaign in rural Lesotho resulted in an increase in testing coverage of 21% compared to a testing campaign without secondary distribution. This study aims to determine the per patient costs of both HOSENG trial arms. Method: We conducted a micro-costing study to estimate the cost of home-based HIV testing with (HOSENG intervention arm) and without (HOSENG control arm) secondary self-test distribution from a provider's perspective. A mixture of top-down and bottom-up costing was used. We estimated both the financial and economic per patient costs of each possible testing cascade scenario. The costs were adjusted to 2018 US36,481 among the 4,174 persons enumerated and 3,094 eligible for testing in the intervention villages compared to US11.79 in the intervention vs. US15.70 vs. US889.79 in the intervention and US$753.17 in the control. Conclusion: During home-based HIV testing in Lesotho, the secondary distribution of self-tests for persons absent or refusing to test during the visit reduced the costs per person tested and thus presents a promising add-on for such campaigns. Trial Registration:https://ClinicalTrials.gov/, identifier: NCT03598686
A Cepheid Distance to NGC 4603 in Centaurus
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
Cepheids and Long Period Variables in NGC 4395
Repeated imaging observations of NGC 4395 were made with the WIYN 3.5 m and
the KPNO 2.1 m telescopes. From the photometry of the resolved brighter stars
in this galaxy eleven Cepheids with periods ranging between 12 and 90 days have
been identified. The true distance modulus has been derived from the apparent
distance moduli in g, r and i. The distance modulus is 28.02 +/- 0.18 based on
the LMC P-L relation by Sandage et al. 2003; this corresponds to a distance of
4.0 +/- 0.3 Mpc. Using the P-L relation from Madore & Freedman 1991, the
distance modulus is 28.15 +/- 0.18; which corresponds to a distance of 4.3 +/-
0.4 Mpc. The reddening is calculated to be E(g-r) = 0.06 +/- 0.08 and E(r-i) =
0.10 +/- 0.08, again from the distance moduli mu_g, mu_r and mu_i. In addition,
37 other variables have been detected, the majority of which have definite
periods. They are probably all red long period variables.Comment: 54 pages, 8 figures, 8 tables, accepted for publication in the
Astronomical Journa
Mean JHK Magnitudes of Fundamental-Mode Cepheids from Single-Epoch Observations
We present an empirical method for converting single-point near-infrared J,
H, and K measurements of fundamental-mode Cepheids to mean magnitudes, using
complete light curves in V or I bands. The algorithm is based on the template
light curves in the near-infrared bandpasses. The mean uncertainty of the
method is estimated to about 0.03 mag, which is smaller than the uncertainties
obtained in other approaches to the problem in the literature.Comment: 20 pages, 5 figures, 4 table
Effectiveness of a peer educator-coordinated preference-based differentiated service delivery model on viral suppression among young people living with HIV in Lesotho: the PEBRA cluster-randomized trial
BACKGROUND: Southern and Eastern Africa is home to more than 2.1 million young people aged 15 to 24 years living with HIV. As compared with other age groups, this population group has poorer outcomes along the HIV care cascade. Young people living with HIV and the research team co-created the PEBRA (Peer Educator-Based Refill of ART) care model. In PEBRA, a peer educator (PE) delivered services as per regularly assessed patient preferences for medication pick-up, short message service (SMS) notifications, and psychosocial support. The cluster-randomized trial compared PEBRA model versus standard clinic care (no PE and ART refill done by nurses) in 3 districts in Lesotho. METHODS AND FINDINGS: Individuals taking antiretroviral therapy (ART) aged 15 to 24 years at 20 clinics (clusters) were eligible. In the 10 clinics randomized to the intervention arm, participants were offered the PEBRA model, coordinated by a trained PE and supported by an eHealth application (PEBRApp). In the 10 control clusters, participants received standard nurse-coordinated care without any service coordination by a PE. The primary endpoint was 12-month viral suppression below 20 copies/mL. Analyses were intention-to-treat and adjusted for sex. From November 6, 2019 to February 4, 2020, we enrolled 307 individuals (150 intervention, 157 control; 218 [71%] female, median age 19 years [interquartile range, IQR, 17 to 22]). At 12 months, 99 of 150 (66%) participants in the intervention versus 95 of 157 (61%) participants in the control arm had viral suppression (adjusted odds ratio (OR) 1.27; 95% confidence interval [CI] [0.79 to 2.03]; p = 0.327); 4 of 150 (2.7%) versus 1 of 157 (0.6%) had died (adjusted OR 4.12; 95% CI [0.45 to 37.62]; p = 0.210); and 12 of 150 (8%) versus 23 of 157 (14.7%) had transferred out (adjusted OR 0.53; 95% CI [0.25 to 1.13]; p = 0.099). There were no significant differences between arms in other secondary outcomes. Twenty participants (11 in intervention and 9 in control) were lost to follow-up over the entire study period. The main limitation was that the data collectors in the control clusters were also young peers; however, they used a restricted version of the PEBRApp to collect data and thus were not able to provide the PEBRA model. The trial was prospectively registered on ClinicalTrials.gov (NCT03969030). CONCLUSIONS: Preference-based peer-coordinated care for young people living with HIV, compared to nurse-based care only, did not lead to conclusive evidence for an effect on viral suppression. TRIAL REGISTRATION: clinicaltrials.gov, NCT03969030, https://clinicaltrials.gov/ct2/show/NCT03969030
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