807 research outputs found

    Population structure, long-term connectivity, and effective size of mutton snapper (Lutjanus analis) in the Caribbean Sea and Florida Keys

    Get PDF
    Genetic structure and average long-term connectivity and effective size of mutton snapper (Lutjanus analis) sampled from offshore localities in the U.S. Caribbean and the Florida Keys were assessed by using nuclear-encoded microsatellites and a fragment of mitochondrial DNA. No significant differences in allele, genotype (microsatellites), or haplotype (mtDNA) distributions were detected; tests of selective neutrality (mtDNA) were nonsignificant after Bonferroni correction. Heuristic estimates of average long-term rate of migration (proportion of migrant individuals/generation) between geographically adjacent localities varied from 0.0033 to 0.0054, indicating that local subpopulations could respond independently of environmental perturbations. Estimates of average longterm effective population sizes varied from 341 to 1066 and differed significantly among several of the localities. These results indicate that over time larval drift and interregional adult movement may not be sufficient to maintain population sustainability across the region and that there may be different demographic stocks at some of the localities studied. The estimate of long-term effective population size at the locality offshore of St. Croix was below the minimum threshold size considered necessary to maintain the equilibrium between the loss of adaptive genetic variance from genetic drift and its replacement by mutation. Genetic variability in mutton snapper likely is maintained at the intraregional level by aggregate spawning and random mating of local populations. This feature is perhaps ironic in that aggregate spawning also renders mutton snapper especially vulnerable to overexploitation

    POES satellite observations of EMIC-wave driven relativistic electron precipitation during 1998-2010

    Get PDF
    [1] Using six Polar Orbiting Environmental Satellites (POES) satellites that have carried the Space Environment Module-2 instrument package, a total of 436,422 individual half-orbits between 1998 and 2010 were inspected by an automatic detection algorithm searching for electromagnetic ion cyclotron (EMIC) driven relativistic electron precipitation (REP). The algorithm searched for one of the key characteristics of EMIC-driven REP, identified as the simultaneity between spikes in the P1 (52 keV differential proton flux channel) and P6 (>800 keV electron channel). In all, 2331 proton precipitation associated REP (PPAREP) events were identified. The majority of events were observed at L-values within the outer radiation belt (3 < L < 7) and were more common in the dusk and night sectors as determined by magnetic local time. The majority of events occurred outside the plasmasphere, at L-values ~1 Re greater than the plasmapause location determined from two different statistical models. The events make up a subset of EMIC-driven proton spikes investigated by Sandanger et al. (2009), and potentially reflect different overall characteristics compared with proton spikes, particularly when comparing their location to that of the plasmapause, i.e., EMIC-driven proton precipitation inside the plasmapause, and potentially EMIC-driven REP outside the plasmapause. There was no clear relationship between the location of plasmaspheric plumes and the locations of the PPAREP events detected. Analysis of the PPAREP event occurrence indicates that high solar wind speed and high geomagnetic activity levels increase the likelihood of an event being detected. The peak PPAREP event occurrence was during the declining phase of solar cycle 23, consistent with the 2003 maximum in the geomagnetic activity index, Ap

    The Structure of Nuclear Star Clusters in Nearby Late-type Spiral Galaxies from Hubble Space Telescope Wide Field Camera 3 Imaging

    Full text link
    We obtained Hubble Space Telescope/Wide Field Camera 3 imaging of a sample of ten of the nearest and brightest nuclear clusters residing in late-type spiral galaxies, in seven bands that span the near-ultraviolet to the near-infrared. Structural properties of the clusters were measured by fitting two-dimensional surface brightness profiles to the images using GALFIT. The clusters exhibit a wide range of structural properties. For six of the ten clusters in our sample, we find changes in the effective radius with wavelength, suggesting radially varying stellar populations. In four of the objects, the effective radius increases with wavelength, indicating the presence of a younger population which is more concentrated than the bulk of the stars in the cluster. However, we find a general decrease in effective radius with wavelength in two of the objects in our sample, which may indicate extended, circumnuclear star formation. We also find a general trend of increasing roundness of the clusters at longer wavelengths, as well as a correlation between the axis ratios of the NCs and their host galaxies. These observations indicate that blue disks aligned with the host galaxy plane are a common feature of nuclear clusters in late-type galaxies, but are difficult to detect in galaxies that are close to face-on. In color-color diagrams spanning the near-UV through the near-IR, most of the clusters lie far from single-burst evolutionary tracks, showing evidence for multi-age populations. Most of the clusters have integrated colors consistent with a mix of an old population (> 1 Gyr) and a young population (~100-300 Myr). The wide wavelength coverage of our data provides a sensitivity to populations with a mix of ages that would not be possible to achieve with imaging in optical bands only.Comment: Corrected a typo in author name and affiliation for MC and corrected a typo in the conclusio

    Duration-dependent effects of the BDNF Val66Met polymorphism on anodal tDCS induced motor cortex plasticity in older adults: a group and individual perspective

    Get PDF
    The brain derived neurotrophic factor (BDNF) Val66Met polymorphism and stimulation duration are thought to play an important role in modulating motor cortex plasticity induced by non-invasive brain stimulation (NBS). In the present study we sought to determine whether these factors interact or exert independent effects in older adults. Fifty-four older adults (mean age = 66.85 years) underwent two counterbalanced sessions of 1.5 mA anodal transcranial direct current stimulation (atDCS), applied over left M1 for either 10 min or 20 min. Single pulse transcranial magnetic stimulation (TMS) was used to assess corticospinal excitability (CSE) before and every 5 min for 30 min following atDCS. On a group level, there was an interaction between stimulation duration and BDNF genotype, with Met carriers (n =13) showing greater post-intervention potentiation of CSE compared to Val66Val homozygotes (n = 37) following 20 min (p = 0.002) but not 10 min (p = 0.219) of stimulation. Moreover, Met carriers, but not Val66Val homozygotes, exhibited larger responses to TMS (p = 0.046) after 20 min atDCS, than following 10 min atDCS. On an individual level, two-step cluster analysis revealed a considerable degree of inter-individual variability, with under half of the total sample (42%) showing the expected potentiation of CSE in response to atDCS across both sessions. Intra-individual variability in response to different durations of atDCS was also apparent, with one-third of the total sample (34%) exhibiting LTP-like effects in one session but LTD-like effects in the other session. Both the inter-individual (p = 0.027) and intra-individual (p = 0.04) variability was associated with BDNF genotype.In older adults, the BDNF Val66Met polymorphism along with stimulation duration appears to play a role in modulating tDCS-induced motor cortex plasticity. The results may have implications for the design of NBS protocols for healthy and diseased aged populations

    Population Structure, Long-Term Connectivity, and Effective Size of Mutton Snapper (\u3ci\u3eLutjanus analis\u3c/i\u3e) In the Caribbean Sea and Florida Keys

    Get PDF
    Genetic structure and average long-term connectivity and effective size of mutton snapper (Lutjanus analis) sampled from offshore localities in the U.S. Caribbean and the Florida Keys were assessed by using nuclear-encoded microsatellites and a fragment of mitochondrial DNA. No significant differences in allele, genotype (microsatellites), or haplotype (mtDNA) distributions were detected; tests of selective neutrality (mtDNA) were nonsignificant after Bonferroni correction. Heuristic estimates of average long-term rate of migration (proportion of migrant individuals/generation) between geographically adjacent localities varied from 0.0033 to 0.0054, indicating that local subpopulations could respond independently of environmental perturbations. Estimates of average long-term effective population sizes varied from 341 to 1066 and differed significantly among several of the localities. These results indicate that over time larval drift and interregional adult movement may not be sufficient to maintain population sustainability across the region and that there may be different demographic stocks at some of the localities studied. The estimate of long-term effective population size at the locality offshore of St. Croix was below the minimum threshold size considered necessary to maintain the equilibrium between the loss of adaptive genetic variance from genetic drift and its replacement by mutation. Genetic variability in mutton snapper likely is maintained at the intraregional level by aggregate spawning and random mating of local populations. This feature is perhaps ironic in that aggregate spawning also renders mutton snapper especially vulnerable to overexploitation

    Nature and type of patient-reported safety incidents in primary care: Cross-sectional survey of patients from Australia and England

    Get PDF
    Background Patient engagement in safety has shown positive effects in preventing or reducing adverse events and potential safety risks. Capturing and utilising patient-reported safety incident data can be used for service learning and improvement. Objective The aim of this study was to characterise the nature of patient-reported safety incidents in primary care. Design Secondary analysis of two cross sectional studies. Participants Adult patients from Australian and English primary care settings. Measures Patients’ self-reported experiences of safety incidents were captured using the validated Primary Care Patient Measure of Safety questionnaire. Qualitative responses to survey items were analysed and categorised using the Primary Care Patient Safety Classification System. The frequency and type of safety incidents, contributory factors, and patient and system level outcomes are presented. Results A total of 1329 patients (n=490, England; n=839, Australia) completed the questionnaire. Overall, 5.3% (n=69) of patients reported a safety incident over the preceding 12 months. The most common incident types were administration incidents (n=27, 31%) (mainly delays in accessing a physician) and incidents involving diagnosis and assessment (n=16, 18.4%). Organisation of care accounted for 27.6% (n=29) of the contributory factors identified in the safety incidents. Staff factors (n=13, 12.4%) was the second most commonly reported contributory factor. Where an outcome could be determined, patient inconvenience (n=24, 28.6%) and clinical harm (n=21, 25%) (psychological distress and unpleasant experience) were the most frequent. Conclusions The nature and outcomes of patient-reported incidents differ markedly from those identified in studies of staff-reported incidents. The findings from this study emphasise the importance of capturing patient-reported safety incidents in the primary care setting. The patient perspective can complement existing sources of safety intelligence with the potential for service improvement

    High-impact jumping mitigates the short-term effects of low energy availability on bone resorption but not formation in regularly menstruating females:A randomized control trial

    Get PDF
    Low energy availability (LEA) is prevalent in active individuals and negatively impacts bone turnover in young females. High-impact exercise can promote bone health in an energy efficient manner and may benefit bone during periods of LEA. Nineteen regularly menstruating females (aged 18–31 years) participated in two three-day conditions providing 15 (LEA) and 45 kcals kg fat-free mass−1 day−1 (BAL) of energy availability, each beginning 3 ± 1 days following the self-reported onset of menses. Participants either did (LEA+J, n = 10) or did not (LEA, n = 9) perform 20 high-impact jumps twice per day during LEA, with P1NP, β-CTx (circulating biomarkers of bone formation and resorption, respectively) and other markers of LEA measured pre and post in a resting and fasted state. Data are presented as estimated marginal mean ± 95% CI. P1NP was significantly reduced in LEA (71.8 ± 6.1–60.4 ± 6.2 ng mL−1, p 0.999, d = 0.19), and these effects were significantly different (time by condition interaction: p = 0.007). Morning basal bone formation rate is reduced following 3 days LEA, induced via dietary restriction, with or without high-impact jumping in regularly menstruating young females. However, high-impact jumping can prevent an increase in morning basal bone resorption rate and may benefit long-term bone health in individuals repeatedly exposed to such bouts

    COVID-19: Beyond Washing Your Hands and Social Distancing

    Get PDF
    A pandemic due to the outbreak of the COVID-19 virus was declared as of March 2020. The authors provide perspective towards preventing and/or mitigating the impact of contracting the virus known as COVID-19. The authors posit straightforward strategies that an individual could implement that may decrease the likelihood of developing COVID-19, help lessen the severity of the symptoms related to the COVID-19 and potentially mitigate the transmission of the virus. The authors consider their comments as food for thought and not as professional medical advice. If you believe you have contracted the COVID-19 virus seek the advice of your healthcare provider

    Grip Strength and Functional Measures in the Mature Adult: Brief Report II

    Get PDF
    Grip strength has been shown to be closely linked to body strength in mature aged adults. However what may be of greater importance is the relationship between grip strength and functional movements in aging adults. Purpose: This study examined the relationship between grip strength and functional body movements in mature aged adults. Methods: Female (n=12, age=71.2±3.8 years, mass=66.3±9.2 kg) and male (n=16, age=72.9±4.7 years, mass=85.5±9.4 kg) participants completed functional body movements including: vertical jump (VJ), medicine ball (MB) throws (1.5, 3.0, & 5.0 Kgs), and a stair climb (SC) test. Likewise, all participants performed maximal hand grip (MG) with the Jamar hand grip dynamometer. Pearson correlation coefficients (PCC) were then calculated to determine the relationship between dominant hand MG and the functional body movement scores. Results: PCC’s were as follows: MG-VJ (r=0.62), MG-MB1.5 (r=0.86), MG-MB3.0 (r=0.87), MG-MB5.0 (r=0.91), and MG-SCP (r=0.79). All PCC’s were statistically significant at P\u3c0.01. Conclusions: Within the parameters of this study, MG strength is strongly reflective of functional body movements that require upper and lower body power output. In this regard, assessing grip strength may be beneficial to clinicians interested in assessing functional body movements in aging adults
    corecore