537 research outputs found
Time varying Na I D absorption in ILRTs as a probe of circumstellar material
Intermediate-Luminosity Red Transients (ILRTs) are a class of observed
transient posited to arise from the production of an electron-capture supernova
from a super-asymptotic giant branch star within a dusty cocoon. In this paper,
we present a systematic analysis of narrow Na I D absorption as a means of
probing the circumstellar environment of these events. We find a wide diversity
of evolution in ILRTs in terms of line strength, time-scale, and shape. We
present a simple toy model designed to predict this evolution as arising from
ejecta from a central supernova passing through a circumstellar environment
wherein Na II is recombining to Na I over time. We find that while our toy
model can qualitatively explain the evolution of a number of ILRTs, the
majority of our sample undergoes evolution more complex than predicted. The
success of using the Na I D doublet as a diagnostic tool for studying
circumstellar material will rely on the availability of regular high-resolution
spectral observations of multiple ILRTs, and more detailed spectral modelling
will be required to produce models capable of explaining the diverse range of
behaviours exhibited by ILRTs. In addition, the strength of the Na I D
absorption feature has been used as a means of estimating the extinction of
sources, and we suggest that the variability visible in ILRTs would prevent
such methods from being used for this class of transient, and any others
showing evidence of variabilityComment: 14 pages, 10 figures, submitted to MNRA
The effect of hypoglycaemia during hospital admission on health-related outcomes for people with diabetes: a systematic review and meta-analysis
Aims: To assess the health-related outcomes of hypoglycaemia for people with diabetes admitted to hospital; specifically, hospital length of stay and mortality.Methods: We conducted a systematic review and meta-analysis of studies relating to inpatient hypoglycaemia (<4 mmol/L) for hospitalised adults (≥16 years) with diabetes reporting the primary outcomes of interest, hospital length of stay or mortality. Final papers for inclusion were reviewed in duplicate and the adjusted results of each were pooled, using a random effects model then undergoing further prespecified subgroup analysis.Results: 15 studies were included in the meta-analysis. The pooled mean difference in length of stay for ward-based inpatients exposed to hypoglycaemia was 4.1 days longer (95% confidence interval [CI], 2.36-5.79; IÇ = 99%) compared to inpatients without hypoglycaemia. This association remained robust across the pre-specified subgroup analyses. The pooled relative risk (RR) of in-hospital mortality was greater for inpatients exposed to hypoglycaemia 2.09 (95% CI, 1.64 to 2.67; IÇ = 94%, n=7 studies) but not in intensive care unit mortality RR 0.75 (0.49 to 1.16; IÇ =0%, n=2 studies).Conclusion: There is an association between inpatient hypoglycaemia and longer length of stay and greater in-hospital mortality. Studies examining this association were heterogenous in terms of both clinical populations and effect size, but the overall direction of the association was consistent. Therefore, glucose concentration should be considered a potential tool to aid the identification of patients at risk of poor health-related outcomes
Isolation, characterization, and cross‐amplification of 20 microsatellite markers for Conospermum undulatum (Proteaceae)
PREMISE: Recent habitat fragmentation is posing a risk to the wavy‐leaved smokebush, Conospermum undulatum (Proteaceae), a rare plant species endemic to southwestern Western Australia. Microsatellite markers are required to characterize the genetic diversity and structure of the species for conservation purposes and to facilitate ecological studies.
METHODS AND RESULTS: Illumina MiSeq high‐throughput sequencing was used to develop 20 novel microsatellite markers for C. undulatum. Polymorphism at each locus was assessed using 72 individuals from three natural populations. Nineteen markers were polymorphic, with the number of alleles per locus ranging from two to 21, and observed and expected heterozygosity ranging from 0.000 to 1.000 and 0.117 to 0.919, respectively. All markers successfully amplified in three congeneric species (C. stoechadis, C. canaliculatum and C. triplinervium).
CONCLUSIONS: The microsatellite markers will be useful for revealing patterns of genetic diversity, dispersal dynamics, and hybridization events for C. undulatum to inform future conservation efforts
Modeling suggests gene editing combined with vaccination could eliminate a persistent disease in livestock
Recent breakthroughs in gene-editing technologies that can render individual animals fully resistant to infections may offer unprecedented opportunities for controlling future epidemics in farm animals. Yet, their potential for reducing disease spread is poorly understood as the necessary theoretical framework for estimating epidemiological effects arising from gene-editing applications is currently lacking. Here, we develop semistochastic modeling approaches to investigate how the adoption of gene editing may affect infectious disease prevalence in farmed animal populations and the prospects and time scale for disease elimination. We apply our models to the porcine reproductive and respiratory syndrome (PRRS), one of the most persistent global livestock diseases to date. Whereas extensive control efforts have shown limited success, recent production of gene-edited pigs that are fully resistant to the PRRS virus have raised expectations for eliminating this deadly disease. Our models predict that disease elimination on a national scale would be difficult to achieve if gene editing was used as the only disease control. However, from a purely epidemiological perspective, disease elimination may be achievable within 3 to 6 y, if gene editing were complemented with widespread and sufficiently effective vaccination. Besides strategic distribution of genetically resistant animals, several other key determinants underpinning the epidemiological impact of gene editing were identified
Initial/boundary-value problems of tumor growth within a host tissue
This paper concerns multiphase models of tumor growth in interaction with a
surrounding tissue, taking into account also the interplay with diffusible
nutrients feeding the cells. Models specialize in nonlinear systems of possibly
degenerate parabolic equations, which include phenomenological terms related to
specific cell functions. The paper discusses general modeling guidelines for
such terms, as well as for initial and boundary conditions, aiming at both
biological consistency and mathematical robustness of the resulting problems.
Particularly, it addresses some qualitative properties such as a priori
nonnegativity, boundedness, and uniqueness of the solutions. Existence of the
solutions is studied in the one-dimensional time-independent case.Comment: 30 pages, 5 figure
Large-Scale Release of Campylobacter Draft Genomes: Resources for Food Safety and Public Health from the 100K Pathogen Genome Project.
Campylobacter is a food-associated bacterium and a leading cause of foodborne illness worldwide, being associated with poultry in the food supply. This is the initial public release of 202 Campylobacter genome sequences as part of the 100K Pathogen Genome Project. These isolates represent global genomic diversity in the Campylobacter genus
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PTSD and DNA Methylation in Select Immune Function Gene Promoter Regions: A Repeated Measures Case-Control Study of U.S. Military Service Members
Background: The underlying molecular mechanisms of PTSD are largely unknown. Distinct expression signatures for PTSD have been found, in particular for immune activation transcripts. DNA methylation may be significant in the pathophysiology of PTSD, since the process is intrinsically linked to gene expression. We evaluated temporal changes in DNA methylation in select promoter regions of immune system-related genes in U.S. military service members with a PTSD diagnosis, pre- and post-diagnosis, and in controls. Methods: Cases (n = 75) had a post-deployment diagnosis of PTSD in their medical record. Controls (n = 75) were randomly selected service members with no PTSD diagnosis. DNA was extracted from pre- and post-deployment sera. DNA methylation (%5-mC) was quantified at specific CpG sites in promoter regions of insulin-like growth factor 2 (IGF2), long non-coding RNA transcript H19, interleukin-8 (IL8), IL16, and IL18 via pyrosequencing. We used multivariate analysis of variance and generalized linear models to calculate adjusted means (adjusted for age, gender, and race) to make temporal comparisons of %5-mC for cases (pre- to post-deployment) versus controls (pre- to post-deployment). Results: There were significant differences in the change of %5-mC pre- to post-deployment between cases and controls for H19 (cases: +0.57%, controls: −1.97%; p = 0.04) and IL18 (cases: +1.39%, controls: −3.83%; p = 0.01). For H19 the difference was driven by a significant reduction in %5-mC among controls; for IL18 the difference was driven by both a reduction in %5-mC among controls and an increase in %5-mC among cases. Stratified analyses revealed more pronounced differences in the adjusted means of pre-post H19 and IL18 methylation differences for cases versus controls among older service members, males, service members of white race, and those with shorter deployments (6–12 months). Conclusion: In the study of deployed personnel, those who did not develop PTSD had reduced %5-mC levels of H19 and IL18 after deployment, while those who did develop PTSD had increased levels of IL18. Additionally, pre-deployment the people who later became cases had lower levels of IL18 %5-mC compared with controls. These findings are preliminary and should be investigated in larger studies
Nonalcoholic Fatty Liver Disease Is Associated With Higher 1-year All-Cause Rehospitalization Rates in Patients Admitted for Acute Heart Failure
Repeat hospitalization due to acute heart failure (HF) is a global public health problem that markedly impacts on health resource use. Identifying novel predictors of rehospitalization would help physicians to determine the optimal postdischarge plan for preventing HF rehospitalization. Nonalcoholic fatty liver disease (NAFLD) is an emerging risk factor for many heart diseases, including HF. We assessed whether NAFLD at hospital admission predicts 1-year all-cause rehospitalization in patients with acute HF.We enrolled all patients consecutively admitted for acute HF to our General Medicine Division, from January 2013 to April 2014, after excluding patients with acute myocardial infarction, severe heart valve diseases, malignancy, known liver diseases, and those with volume overload related to extracardiac causes. NAFLD was diagnosed by ultrasonography and exclusion of competing etiologies. The primary outcome of the study was the 1-year all-cause rehospitalization rate.Among the 107 patients enrolled in the study, the cumulative rehospitalization rate was 12.1% at 1 month, 25.2% at 3 months, 29.9% at 6 months, and 38.3% at 1 year. Patients with NAFLD had markedly higher 1-year rehospitalization rates than those without NAFLD (58% vs 21% at 1 y; P\u200a<\u200a0.001 by the log-rank test). Cox regression analysis revealed that NAFLD was associated with a 5.5-fold increased risk of rehospitalization (adjusted hazard ratio 5.56, 95% confidence interval 2.46-12.1, P\u200a<\u200a0.001) after adjustment for multiple HF risk factors and potential confounders.In conclusion, NAFLD was independently associated with higher 1-year rehospitalization in patients hospitalized for acute HF
Long-term chromospheric activity in southern M dwarfs: Gl 229 A and Gl 752 A
Several late-type stars present activity cycles similar to that of the Sun.
However, these cycles have been mostly studied in F to K stars. Due to their
small intrinsic brightness, M dwarfs are not usually the targets of long-term
observational studies of stellar activity, and their long-term variability is
generally not known. In this work, we study the long-term activity of two M
dwarf stars: Gl 229 A (M1/2) and Gl 752 A (M2.5). We employ medium resolution
echelle spectra obtained at the 2.15 m telescope at the Argentinian observatory
CASLEO between the years 2000 and 2010 and photometric observations obtained
from the ASAS database. We analyzed Ca \II K line-core fluxes and the mean V
magnitude with the Lomb-Scargle periodogram, and we obtain possible activity
cycles of 4 yr and 7 yr for Gl 229 A and Gl 752 A respectively.Comment: Accepted for publication by Astronomical Journal (AJ
Terahertz Magneto Optical Polarization Modulation Spectroscopy
We report the development of new terahertz techniques for rapidly measuring
the complex Faraday angle in systems with broken time-reversal symmetry using
the cyclotron resonance of a GaAs two-dimensional electron gas in a magnetic
field as a system for demonstration of performance. We have made polarization
modulation, high sensitivity (< 1 mrad) narrow band rotation measurements with
a CW optically pumped molecular gas laser, and by combining the distinct
advantages of terahertz (THz) time domain spectroscopy and polarization
modulation techniques, we have demonstrated rapid broadband rotation
measurements to < 5 mrad precision.Comment: 25 pages including 7 figures, introduces use of rotating polarizer
with THz TDS for Complex Faraday Angle determinatio
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