998 research outputs found
Natural Populations of Woodchuck Hepatitis Virus Contain Variant Precore and Core Sequences Including a Premature Stop Codon in the Epsilon Motif
We have determined a consensus sequence and the type and the frequency of spontaneous sequence variations in the woodchuck hepatitis virus (WHV) precore gene and the 5' region of the core gene in 101 serum samples from 53 naturally WHV-infected woodchucks by polymerase chain reaction sequencing. Twenty of the 53 woodchucks were found to have variant sequences. Ten patterns of variant sequences were identified in these 20 animals. WHV sequences from 4 woodchucks had 1 nucleotide change, 3 had 2 nucleotide changes and 3 had 3 nucleotide changes. The nucleotide changes were not randomly distributed, but were limited to only 8 sites. Four sites were in the epsilon motif of the precore gene and four were in the 5' region of the core gene. Sixteen of the 53 (30%) woodchucks had precore sequence variants. All altered sites were analogous to previously described mutations in hepatitis B virus. There was a nucleotide change at nucleotide 2016 in codon 29 of the precore region that produced a stop codon in 4 animals. This site is analogous to a common hepatitis B virus e antigen mutation. The sequence from the initial blood samples from 3 of 4 animals with this stop codon producing variant appeared to be the consensus sequence; however, in later samples the variant occurred as a mixed infection with the consensus sequence. The mixed infections were chronic and the proportion of the variant sequence was maintained or increased in the course of infection. In the fourth animal only the variant was found and it persisted for over 14 months of infection. WHV appears to be a valuable model for the study of the structure and function of the hepadnavirus precore region
The 2p21D and (2p3p + 2s3d)3D autoionizing resonances of the helium isoelectronic sequence.
Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.Sc.)--University of Windsor (Canada), 1973
Anthropometric profiles of elite athletes
Quantifying body composition is central to monitoring performance and training in athletes, however limited sport-specific anthropometric reference data, assessed and reported in a standardised manner, is available. This study provides anthropometric profiles in elite male athletes from different sports. Elite male athletes (n = 73) from National squads of boxing (n = 10), cricket (n = 21), swimming (n = 23), hockey (n = 10) and eventing (n = 9) were assessed for body mass, height, eight skinfolds (triceps, subscapular, biceps, iliac crest, supraspinal, abdominal, thigh and medial calf), body circumferences (arm, waist, hip, thigh and calf) and muscle circumferences (arm, thigh, calf) using ISAK standardised guidelines. For all athletes, large variability exists for measures of skinfold thickness at each skinfold site. Swimming (64.6 ± 16.1 mm) and boxing (63.5 ± 16.1 mm) were similar for the sum of eight skinfolds (Σ8SKF) but swimming had lower Σ8SKF compared to cricket (86.1 ± 21.3 mm; p = .011) and eventing (89.9 ± 30.7 mm; p = .028). Hockey (81.9 ± 26.3 mm) and eventing had the most varied Σ8SKF. Thigh body (p=.006) and muscle circumferences (p = .005) were significantly reduced in boxing compared to hockey. No differences were seen between sports for arm (p = .346; ES = .06) and calf (p = .382; ES = .06) muscle circumferences. The anthropometric profiles for elite athletes from various sports during pre-season training will be a useful resource for sports professionals when monitoring and interpreting body composition data. Large variation exists in anthropometric profiles between the different athletes and different sports, highlighting the necessity to have sport-specific normative ranges available to allow optimal monitoring of individual athletes particularly varying across sports as well as age, training status and position
Determining the sex of Little Penguins (Eudyptula minor) in northern Bass Strait using morphometric measurements
In avian species with no obvious differences in plumage or body size between the sexes, such as penguins, discriminant function analysis (DFA) of morphometric measurements that display sexual dimorphism can provide a simple and rapid means of determining sex in the field. Like most other penguin species, the Little Penguin (Eudyptula minor) displays sexual dimorphism in bill shape and size. In the present study, discriminant functions (DFs) were developed for sexing adult Little Penguins at two colonies in northern Bass Strait, Victoria, Australia, and their accuracies were compared with those obtained previously in other parts of the species\u27 range. Backwards stepwise DFA indicated that birds at Phillip Island can be sexed with an accuracy of 91% using a single measurement of bill depth (>13.33 mm classed as males). Similar analyses at Gibson Steps produced a DF incorporating bill length, bill depth and head length [although the model with the greatest accuracy when applied to birds from Phillip Island (91%) also contained only bill depth]. Published DFs derived in New Zealand had accuracies of 50–85% when applied to birds from Phillip Island and Gibson Steps, supporting earlier suggestions that DFs are not applicable across subspecies of the Little Penguin. In contrast, there was little difference between the accuracy of the DFs in the present study and that previously derived for the same subspecies in Tasmania when applied to birds from Phillip Island (89%) and Gibson Steps (92%). However, as the degree of variation in bill size within a subspecies is unknown it may still be prudent to derive colony-specific DFs.<br /
From genes to ecosystems: the ocean\u27s new frontier
The application of new molecular and genomic techniques to the ocean is driving a scientific revolution in marine microbiology. Discoveries range from previously unknown groups of organisms and novel metabolic pathways to a deeper appreciation of the fundamental genetic and functional diversity of oceanic microbes. The “oceanic genotype” represents only the potential biological capacity and sets an upper constraint on possible pathways and ecosystem rates. The realized structure and functioning of marine ecosystems, the “oceanic phenotype”, reflects the complex interactions of individuals and populations with their physical and chemical environment and with each other. A comprehensive exploitation of the wealth of new genomic data therefore requires a close synergy with interdisciplinary ocean research. Incorporating the information from environmental genomics, targeted process studies, and ocean observing systems into numerical models will improve predictions of the ocean\u27s response to environmental perturbations. Integrating information from genes, populations, and ecosystems is the next great challenge for oceanography
Spiral Evolution in a Confined Geometry
Supported nanoscale lead crystallites with a step emerging from a
non-centered screw dislocation on the circular top facet were prepared by rapid
cooling from just above the melting temperature. STM observations of the top
facet show a nonuniform rotation rate and shape of the spiral step as the
crystallite relaxes. These features can be accurately modeled using curvature
driven dynamics, as in classical models of spiral growth, with boundary
conditions fixing the dislocation core and regions of the step lying along the
outer facet edge.Comment: 4 pages, 3 figures, to be published in Physical Review Letter
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Mental health in UK Biobank - development, implementation and results from an online questionnaire completed by 157 366 participants: a reanalysis
Background
UK Biobank is a well-characterised cohort of over 500 000 participants including genetics, environmental data and imaging. An online mental health questionnaire was designed for UK Biobank participants to expand its potential.
Aims
Describe the development, implementation and results of this questionnaire.
Method
An expert working group designed the questionnaire, using established measures where possible, and consulting a patient group. Operational criteria were agreed for defining likely disorder and risk states, including lifetime depression, mania/hypomania, generalised anxiety disorder, unusual experiences and self-harm, and current post-traumatic stress and hazardous/harmful alcohol use.
Results
A total of 157 366 completed online questionnaires were available by August 2017. Participants were aged 45–82 (53% were ≥65 years) and 57% women. Comparison of self-reported diagnosed mental disorder with a contemporary study shows a similar prevalence, despite respondents being of higher average socioeconomic status. Lifetime depression was a common finding, with 24% (37 434) of participants meeting criteria and current hazardous/harmful alcohol use criteria were met by 21% (32 602), whereas other criteria were met by less than 8% of the participants. There was extensive comorbidity among the syndromes. Mental disorders were associated with a high neuroticism score, adverse life events and long-term illness; addiction and bipolar affective disorder in particular were associated with measures of deprivation.
Conclusions
The UK Biobank questionnaire represents a very large mental health survey in itself, and the results presented here show high face validity, although caution is needed because of selection bias. Built into UK Biobank, these data intersect with other health data to offer unparalleled potential for crosscutting biomedical research involving mental health
Neutrino-Induced Giant Air Showers in Large Extra Dimension Models
In models based on large extra dimensions where massive spin 2 exchange can
dominate at high energies, the neutrino-proton cross section can rise to
typical hadronic values at energies above 10^20 eV. The neutrino then becomes a
candidate for the primary that initiates the highest energy cosmic ray showers.
We investigate characteristics of neutrino-induced showers compared to
proton-induced showers. The comparison includes study of starting depth,
profile with depth, lateral particle distribution at ground and muon lateral
distribution at ground level. We find that for cross sections above 20 mb there
are regions of parameter space where the two types of showers are essentially
indistinguishable. We conclude that the neutrino candidate hypothesis cannot be
ruled out on the basis of shower characteristics.Comment: 24 pages, latex, 19 figures; text discussion and references added,
typos corrected; figures and conclusions unchange
Heart Fatty Acid Binding Protein and cardiac troponin: development of an optimal rule-out strategy for acute myocardial infarction
Background: Improved ability to rapidly rule-out Acute Myocardial Infarction (AMI) in patients presenting with chest pain will promote decongestion of the Emergency Department (ED) and reduce unnecessary hospital admissions. We assessed a new commercial Heart Fatty Acid Binding Protein (H-FABP) assay for additional diagnostic value when combined with cardiac troponin (using a high sensitivity assay). Methods: H-FABP and high-sensitivity troponins I (hs-cTnI) and T (hs-cTnT) were measured in samples taken on-presentation from patients, attending the ED, with symptoms triggering investigation for possible acute coronary syndrome. The optimal combination of H-FABP with each hs-cTn was defined as that which maximized the proportion of patients with a negative test (low-risk) whilst maintaining at least 99 % sensitivity for AMI. A negative test comprised both H-FABP and hs-cTn below the chosen threshold in the absence of ischemic changes on the ECG. Results: One thousand seventy-nine patients were recruited including 248 with AMI. H-FABP 99 % sensitivity for AMI whilst classifying 40.9 % of patients as low-risk. The combination of H-FABP < 3.9 ng/mL and hs-cTnT < 7.6 ng/L with a negative ECG maintained the same sensitivity whilst classifying 32.1 % of patients as low risk. Conclusions: In patients requiring rule-out of AMI, the addition of H-FABP to hs-cTn at presentation (in the absence of new ischaemic ECG findings) may accelerate clinical diagnostic decision making by identifying up to 40 % of such patients as low-risk for AMI on the basis of blood tests performed on presentation. If implemented this has the potential to significantly accelerate triaging of patients for early discharge from the ED
Extensive hydrogen supersaturations in the western South Atlantic Ocean suggest substantial underestimation of nitrogen fixation
The nitrogen cycle is fundamental to Earth's biogeochemistry. Yet major uncertainties of quantification remain, particularly regarding the global oceanic nitrogen fixation rate. Hydrogen is produced during nitrogen fixation and will become supersaturated in surface waters if there is net release from diazotrophs. Ocean surveys of hydrogen supersaturation thus have the potential to illustrate the spatial and temporal distribution of nitrogen fixation, and to guide the far more onerous but quantitative methods for measuring it. Here we present the first transect of high resolution measurements of hydrogen supersaturations in surface waters along a meridional 10,000 km cruise track through the Atlantic. We compare measured saturations with published measurements of nitrogen fixation rates and also with model-derived values. If the primary source of excess hydrogen is nitrogen fixation and has a hydrogen release ratio similar to Trichodesmium, our hydrogen measurements would point to similar rates of fixation in the North and South Atlantic, roughly consistent with modelled fixation rates but not with measured rates, which are lower in the south. Possible explanations would include any substantial nitrogen fixation by newly discovered diazotrophs, particularly any having a hydrogen release ratio similar to or exceeding that of Trichodesmium; under-sampling of nitrogen fixation south of the equator related to excessive focus on Trichodesmium; and methodological shortcomings of nitrogen fixation techniques that cause a bias towards colonial diazotrophs relative to unicellular forms. Alternatively our data are affected by an unknown hydrogen source that is greater in the southern half of the cruise track than the northern
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