2,051 research outputs found
Physical properties of two low-luminosity z ~ 1.9 galaxies behind the lensing cluster AC 114
We present VLT/ISAAC near-infrared spectroscopy of two gravitationally-lensed
z ~ 1.9 galaxies, A2 and S2, located behind the cluster AC 114. Thanks to large
magnification factors, we have been successful in detecting rest-frame optical
emission lines in star-forming galaxies 1 to 2 magnitudes fainter than in
previous studies of Lyman break galaxies (LBGs) at z ~ 3. From the Ha
luminosity, we estimate star formation rates (SFRs) which are 7 to 15 times
higher than those inferred from the UV continuum flux at 1500 ang without dust
extinction correction. The behavior of S2 and A2 in terms of O/H and N/O
abundance ratios are very different, and they are also different from typical
LBGs at z ~ 3. S2 is a low-metallicity object (Z ~ 0.03 Zsun) with a low N/O
ratio, similar to those derived in the most metal-poor nearby HII galaxies. In
contrast, A2 is a high-metallicity galaxy (Z ~ 1.3 Zsun) with a high N/O
abundance ratio, similar to those derived in the most metal-rich starburst
nucleus galaxies. The virial masses, derived from emission-line widths, are 0.5
and 2.4 x 10^10 Msun, for S2 and A2 respectively. Thanks to the gravitational
amplification, the line profiles of S2 are spatially resolved, leading to a
velocity gradient of +- 240 km/s, which yields a dynamical mass of ~ 1.3 x
10^10 Msun within the inner 1 kpc radius. Combining these new data with the
sample of LBGs at z ~ 3, we conclude that these three galaxies exhibit
different physical properties in terms of SFRs, abundance and mass-to-light
ratios, and reddening. High-redshift galaxies of different luminosities could
thus have quite different star formation histories (abridged version).Comment: 11 pages, 8 figures. Accepted for publication in A&
Mapping the submillimeter spiral wave in NGC 6946
We have analysed SCUBA 850\mum images of the (near) face-on spiral galaxy NGC
6946, and found a tight correlation between dust thermal emission and molecular
gas. The map of visual optical depth relates well to the distribution of
neutral gas (HI+H2) and implies a global gas-to-dust ratio of 90. There is no
significant radial variation of this ratio: this can be understood, since the
gas content is dominated by far by the molecular gas. The latter is estimated
through the CO emission tracer, which is itself dependent on metallicity,
similarly to dust emission. By comparing the radial profile of our visual
optical depth map with that of the SCUBA image, we infer an emissivity (dust
absorption coefficient) at 850\mum that is 3 times lower than the value
measured by COBE in the Milky Way, and 9 times lower than in NGC 891. A
decomposition of the spiral structure half way out along the disk of NGC 6946
suggests an interarm optical depth of between 1 and 2. These surprisingly high
values represent 40-80% of the visual opacity that we measure for the arm
region (abridged).Comment: 12 pages, 9 figures, accepted in A&
Vote buying or (political) business (cycles) as usual?
We study the short-run effect of elections on monetary aggregates in a sample of 85 low and middle income democracies (1975-2009). We find an increase in the growth rate of M1 during election months of about one tenth of a standard deviation. A similar effect can neither be detected in established OECD democracies nor in other months. The effect is larger in democracies with many poor and uneducated voters, and in Sub-Saharan Africa, Latin America, and in East-Asia and the Pacific. We argue that the election month monetary expansion is related to systemic vote buying which requires significant amounts of cash to be disbursed right before elections. The finely timed increase in M1 is consistent with this; is inconsistent with a monetary cycle aimed at creating an election time boom; and it cannot be, fully, accounted for by alternative explanations
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
Integral field spectroscopy of a sample of nearby galaxies: II. Properties of the H ii regions
In this work we analyze the spectroscopic properties of a large number of H
ii regions, \sim2600, located in 38 galaxies. The sample of galaxies has been
assembled from the face-on spirals in the PINGS survey and a sample described
in M\'armol-Queralt\'o (2011, henceforth Paper I). All the galaxies were
observed using Integral Field Spectroscopy with a similar setup, covering their
optical extension up to \sim2.4 effective radii within a wavelength range from
\sim3700 to \sim6900{\AA}. We develop a new automatic procedure to detect H ii
regions, based on the contrast of the H{\alpha} intensity maps. Once detected,
the procedure provides us with the integrated spectra of each individual
segmented region. A well-tested automatic decoupling procedure has been applied
to remove the underlying stellar population, deriving the main proper- ties of
the strongest emission lines in the considered wavelength range (covering from
[O ii] {\lambda}3727 to [S ii] {\lambda}6731). A final catalogue of the
spectroscopic properties of these regions has been created for each galaxy. In
the current study we focused on the understanding of the average properties of
the H ii regions and their radial distributions. We find that the gas-phase
oxygen abundance and the H{\alpha} equivalent width present negative and
positive gradient, respectively. The distribution of slopes is statistically
compatible with a random Gaussian distribution around the mean value, if the
radial distances are measured in units of the respective effective radius. No
difference in the slope is found for galaxies of different morphologies:
barred/non-barred, grand-design/flocculent. Therefore, the effective radius is
a universal scale length for gradients in the evolution of galaxies. Other
properties have a larger variance across each object.Comment: 29 pages, 13 figures, accepted for publishing in Astronomy and
Astrophysics (A&A
The continuity of effect of schizophrenia polygenic risk score and patterns of cannabis use on transdiagnostic symptom dimensions at first-episode psychosis: findings from the EU-GEI study
Diagnostic categories do not completely reflect the heterogeneous expression of psychosis. Using data from the EU-GEI study, we evaluated the impact of schizophrenia polygenic risk score (SZ-PRS) and patterns of cannabis use on the transdiagnostic expression of psychosis. We analysed first-episode psychosis patients (FEP) and controls, generating transdiagnostic dimensions of psychotic symptoms and experiences using item response bi-factor modelling. Linear regression was used to test the associations between these dimensions and SZ-PRS, as well as the combined effect of SZ-PRS and cannabis use on the dimensions of positive psychotic symptoms and experiences. We found associations between SZ-PRS and (1) both negative (B = 0.18; 95%CI 0.03–0.33) and positive (B = 0.19; 95%CI 0.03–0.35) symptom dimensions in 617 FEP patients, regardless of their categorical diagnosis; and (2) all the psychotic experience dimensions in 979 controls. We did not observe associations between SZ-PRS and the general and affective dimensions in FEP. Daily and current cannabis use were associated with the positive dimensions in FEP (B = 0.31; 95%CI 0.11–0.52) and in controls (B = 0.26; 95%CI 0.06–0.46), over and above SZ-PRS. We provide evidence that genetic liability to schizophrenia and cannabis use map onto transdiagnostic symptom dimensions, supporting the validity and utility of the dimensional representation of psychosis. In our sample, genetic liability to schizophrenia correlated with more severe psychosis presentation, and cannabis use conferred risk to positive symptomatology beyond the genetic risk. Our findings support the hypothesis that psychotic experiences in the general population have similar genetic substrates as clinical disorders
Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study
Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised
Estimating the Production Function for Human Capital: Results from a Randomized Control Trial in Colombia
Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).
Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)
- …