2,578 research outputs found
Observation of the Far-ultraviolet Continuum Background with SPEAR/FIMS
We present the general properties of the far-ultraviolet (FUV; 1370-1720A)
continuum background over most of the sky, obtained with the Spectroscopy of
Plasma Evolution from Astrophysical Radiation instrument (SPEAR, also known as
FIMS), flown aboard the STSAT-1 satellite mission. We find that the diffuse FUV
continuum intensity is well correlated with N_{HI}, 100 m, and H-alpha
intensities but anti-correlated with soft X-ray. The correlation of the diffuse
background with the direct stellar flux is weaker than the correlation with
other parameters. The continuum spectra are relatively flat. However, a weak
softening of the FUV spectra toward some sight lines, mostly at high Galactic
latitudes, is found not only in direct-stellar but also in diffuse background
spectra. The diffuse background is relatively softer that the direct stellar
spectrum. We also find that the diffuse FUV background averaged over the sky
has about the same level as the direct-stellar radiation field in the
statistical sense and a bit softer spectrum compared to direct stellar
radiation. A map of the ratio of 1400-1510A to 1560-1660A shows that the sky is
divided into roughly two parts. However, this map shows a lot of patchy
structures on small scales. The spatial variation of the hardness ratio seems
to be largely determined by the longitudinal distribution of spectral types of
stars in the Galactic plane. A correlation of the hardness ratio with the FUV
intensity at high intensities is found but an anti-correlation at low
intensities. We also find evidence that the FUV intensity distribution is
log-normal in nature.Comment: 39 pages, 26 figures, accepted for publication in ApJ
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Racial and ethnic disparities in the prescribing of pain medication in US primary care settings, 1999–2019: where are we now?
BACKGROUND: Policy initiatives have attempted to reduce healthcare inequalities in the USA, but evidence on whether these initiatives have reduced racial and ethnic disparities in pain treatment in primary care is lacking. OBJECTIVE: To determine whether racial and ethnic disparities in medication prescribed for pain in primary care settings have diminished over a 21-year period from 1999 to 2019. DESIGN: An annual, representative cross-sectional probability sample of visits to US primary care physicians, taken from the National Ambulatory Medical Care Survey. PATIENTS: Pain-related visits to primary care physicians. MAIN MEASURES: Prescriptions for opioid and non-opioid analgesics. KEY RESULTS: Of 599,293 (16%) sampled visits, 94,422 were pain-related, representing a population-weighted estimate of 143 million visits made annually to primary care physicians for pain. Relative risk analysis controlling for insurance, pain type, and other potential confounds showed no difference in pain medication prescribed between Black and White patients (p = .121). However, White patients were 1.61 (95% CI 1.32-1.97) and Black patients 1.57 (95% CI 1.26-1.95) times more likely to be prescribed opioids than a more underrepresented group consisting of Asian, Native-Hawaiian/Pacific-Islander, and American-Indian/Alaska-Natives (ps < .001). Non-Hispanic/Latino patients were 1.32 (95% CI 1.18-1.45) times more likely to receive opioids for pain than Hispanic/Latino patients (p < .001). Penalized cubic spline regression found no substantive narrowing of disparities over time. CONCLUSIONS: These findings suggest that additional intervention strategies, or better implementation of existing strategies, are needed to eliminate ethnic and racial disparities in pain treatment towards the goal of equitable healthcare
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Efficacy and acceptability of pharmacological and non-pharmacological interventions for non-specific chronic low back pain:a protocol for a systematic review and network meta-analysis
Background: Despite the enormous financial and humanistic burden of chronic low back pain (CLBP), there is little consensus on what constitutes the best treatment options from a multitude of competing interventions. The objective of this network meta-analysis (NMA) is to determine the relative efficacy and acceptability of primary care treatments for non-specific CLBP, with the overarching aim of providing a comprehensive evidence base for informing treatment decisions.
Methods: We will perform a systematic search to identify randomised controlled trials of interventions endorsed in primary care guidelines for the treatment of non-specific CLBP in adults. Information sources searched will include major bibliographic databases (MEDLINE, Embase, CENTRAL, CINAHL, PsycINFO and LILACS) and clinical trial registries. Our primary outcomes will be patient-reported pain ratings and treatment acceptability (all-cause discontinuation), and secondary outcomes will be functional ability, quality of life and patient/physician ratings of overall improvement. A hierarchical Bayesian class-based NMA will be performed to determine the relative effects of different classes of pharmacological (NSAIDs, opioids, paracetamol, anti-depressants, muscle relaxants) and non- pharmacological (exercise, patient education, manual therapies, psychological therapy, multidisciplinary approaches, massage, acupuncture, mindfulness) interventions and individual treatments within a class (e.g. NSAIDs: diclofenac, ibuprofen, naproxen). We will conduct risk of bias assessments and threshold analysis to assess the robustness of the findings to potential bias. We will compute the effect of different interventions relative to placebo/no treatment for both short- and long-term efficacy and acceptability.
Discussion: While many factors are important in selecting an appropriate intervention for an individual patient, evidence for the analgesic effects and acceptability of a treatment are key factors in guiding this selection. Thus, this NMA will provide an important source of evidence to inform treatment decisions and future clinical guidelines
Can Clustal-style progressive pairwise alignment of multiple sequences be used in RNA secondary structure prediction?
<p>Abstract</p> <p>Background</p> <p>In ribonucleic acid (RNA) molecules whose function depends on their final, folded three-dimensional shape (such as those in ribosomes or spliceosome complexes), the secondary structure, defined by the set of internal basepair interactions, is more consistently conserved than the primary structure, defined by the sequence of nucleotides.</p> <p>Results</p> <p>The research presented here investigates the possibility of applying a progressive, pairwise approach to the alignment of multiple RNA sequences by simultaneously predicting an energy-optimized consensus secondary structure. We take an existing algorithm for finding the secondary structure common to two RNA sequences, Dynalign, and alter it to align profiles of multiple sequences. We then explore the relative successes of different approaches to designing the tree that will guide progressive alignments of sequence profiles to create a multiple alignment and prediction of conserved structure.</p> <p>Conclusion</p> <p>We have found that applying a progressive, pairwise approach to the alignment of multiple ribonucleic acid sequences produces highly reliable predictions of conserved basepairs, and we have shown how these predictions can be used as constraints to improve the results of a single-sequence structure prediction algorithm. However, we have also discovered that the amount of detail included in a consensus structure prediction is highly dependent on the order in which sequences are added to the alignment (the guide tree), and that if a consensus structure does not have sufficient detail, it is less likely to provide useful constraints for the single-sequence method.</p
Effects of using coding potential, sequence conservation and mRNA structure conservation for predicting pyrroly-sine containing genes
BACKGROUND: Pyrrolysine (the 22nd amino acid) is in certain organisms and under certain circumstances encoded by the amber stop codon, UAG. The circumstances driving pyrrolysine translation are not well understood. The involvement of a predicted mRNA structure in the region downstream UAG has been suggested, but the structure does not seem to be present in all pyrrolysine incorporating genes. RESULTS: We propose a strategy to predict pyrrolysine encoding genes in genomes of archaea and bacteria. We cluster open reading frames interrupted by the amber codon based on sequence similarity. We rank these clusters according to several features that may influence pyrrolysine translation. The ranking effects of different features are assessed and we propose a weighted combination of these features which best explains the currently known pyrrolysine incorporating genes. We devote special attention to the effect of structural conservation and provide further substantiation to support that structural conservation may be influential – but is not a necessary factor. Finally, from the weighted ranking, we identify a number of potentially pyrrolysine incorporating genes. CONCLUSIONS: We propose a method for prediction of pyrrolysine incorporating genes in genomes of bacteria and archaea leading to insights about the factors driving pyrrolysine translation and identification of new gene candidates. The method predicts known conserved genes with high recall and predicts several other promising candidates for experimental verification. The method is implemented as a computational pipeline which is available on request
smyRNA: A Novel Ab Initio ncRNA Gene Finder
Background: Non-coding RNAs (ncRNAs) have important functional roles in the cell: for example, they regulate gene expression by means of establishing stable joint structures with target mRNAs via complementary sequence motifs. Sequence motifs are also important determinants of the structure of ncRNAs. Although ncRNAs are abundant, discovering novel ncRNAs on genome sequences has proven to be a hard task; in particular past attempts for ab initio ncRNA search mostly failed with the exception of tools that can identify micro RNAs. Methodology/Principal Findings: We present a very general ab initio ncRNA gene finder that exploits differential distributions of sequence motifs between ncRNAs and background genome sequences. Conclusions/Significance: Our method, once trained on a set of ncRNAs from a given species, can be applied to a genome sequences of other organisms to find not only ncRNAs homologous to those in the training set but also others that potentially belong to novel (and perhaps unknown) ncRNA families. Availability
Cost-effectiveness of HBV and HCV screening strategies:a systematic review of existing modelling techniques
Introduction:
Studies evaluating the cost-effectiveness of screening for Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV) are generally heterogeneous in terms of risk groups, settings, screening intervention, outcomes and the economic modelling framework. It is therefore difficult to compare cost-effectiveness results between studies. This systematic review aims to summarise and critically assess existing economic models for HBV and HCV in order to identify the main methodological differences in modelling approaches.
Methods:
A structured search strategy was developed and a systematic review carried out. A critical assessment of the decision-analytic models was carried out according to the guidelines and framework developed for assessment of decision-analytic models in Health Technology Assessment of health care interventions.
Results:
The overall approach to analysing the cost-effectiveness of screening strategies was found to be broadly consistent for HBV and HCV. However, modelling parameters and related structure differed between models, producing different results. More recent publications performed better against a performance matrix, evaluating model components and methodology.
Conclusion:
When assessing screening strategies for HBV and HCV infection, the focus should be on more recent studies, which applied the latest treatment regimes, test methods and had better and more complete data on which to base their models. In addition to parameter selection and associated assumptions, careful consideration of dynamic versus static modelling is recommended. Future research may want to focus on these methodological issues. In addition, the ability to evaluate screening strategies for multiple infectious diseases, (HCV and HIV at the same time) might prove important for decision makers
Spatial Variation in Foraging Behaviour of a Marine Top Predator (Phoca vitulina) Determined by a Large-Scale Satellite Tagging Program
The harbour seal (Phoca vitulina) is a widespread marine predator in Northern Hemisphere waters. British populations have been subject to rapid declines in recent years. Food supply or inter-specific competition may be implicated but basic ecological data are lacking and there are few studies of harbour seal foraging distribution and habits. In this study, satellite tagging conducted at the major seal haul outs around the British Isles showed both that seal movements were highly variable among individuals and that foraging strategy appears to be specialized within particular regions. We investigated whether these apparent differences could be explained by individual level factors: by modelling measures of trip duration and distance travelled as a function of size, sex and body condition. However, these were not found to be good predictors of foraging trip duration or distance, which instead was best predicted by tagging region, time of year and inter-trip duration. Therefore, we propose that local habitat conditions and the constraints they impose are the major determinants of foraging movements. Specifically the distance to profitable feeding grounds from suitable haul-out locations may dictate foraging strategy and behaviour. Accounting for proximity to productive foraging resources is likely to be an important component of understanding population processes. Despite more extensive offshore movements than expected, there was also marked fidelity to the local haul-out region with limited connectivity between study regions. These empirical observations of regional exchange at short time scales demonstrates the value of large scale electronic tagging programs for robust characterization of at-sea foraging behaviour at a wide spatial scale
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