329 research outputs found

    The Origin and Significance of Reverse Zoning in Melilite from Allende Type B Inclusions

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    In many Type B Allende inclusions, melilite is reversely-zoned over restricted portions of each crystal. Textural relationships and the results of dynamic crystallization experiments suggest that the reverselyzoned intervals in these Type melilites result from the co-precipitation of melilite with clinopyroxene from a melt, prior to the onset of anorthite precipitation. When clinopyroxene begins to precipitate, the Al/Mg ratio of the melt rises, causing the crystallizing melilite to become more gehlenitic, an effect which is negated by crystallization of anorthite. Because the equilibrium crystallization sequence in these liquids is anorthite before pyroxene, melilite reverse zoning can occur only when anorthite nucleation is suppressed relative to pyroxene. This has been achieved in our experiments at cooling rates as low as 0.5°C/hour. Our experiments further indicate, however, that reverse zoning does not form at cooling rates ≥50°C/hour , probably because the clinopyroxene becomes too Al-rich to drive up the Al/Mg ratio of the liquid. Type inclusions with reversely-zoned melilites must have cooled at rates greater than those at which anorthite begins to crystallize before clinopyroxene but <50°C/hour. Such rates are far too slow for the Type droplets to have cooled by radiation into a nebular gas but are much faster than the cooling rate of the solar nebula itself. One possibility is that Type B's formed in local hot regions within the nebula, where their cooling rate was equal to that of their surrounding gas. Other possibilities are that their cooling rates reflect their movement along nebular temperature gradients or the influence of a heat source. The sun or viscous drag on inclusions as they moved through the nebular gas are potential candidates for such heat sources

    Using Metareasoning on a Mobile Ground Robot to Recover from Path Planning Failures

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    Autonomous mobile ground robots use global and local path planners to determine the routes that they should follow to achieve mission goals while avoiding obstacles. Although many path planners have been developed, no single one is best for all situations. This paper describes metareasoning approaches that enable a robot to select a new path planning algorithm when the current planning algorithm cannot find a feasible solution. We implemented the approaches within a ROS-based autonomy stack and conducted simulation experiments to evaluate their performance in multiple scenarios. The results show that these metareasoning approaches reduce the frequency of failures and reduce the time required to complete the mission.This work was supported by the U.S. Army Research Laboratory (Award W911NF2120076)

    Tower and Aircraft Eddy Covariance Measurements of Water Vapor, Energy, and Carbon Dioxide Fluxes during SMACEX

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    Abstract A network of eddy covariance (EC) and micrometeorological flux (METFLUX) stations over corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] canopies was established as part of the Soil Moisture–Atmosphere Coupling Experiment (SMACEX) in central Iowa during the summer of 2002 to measure fluxes of heat, water vapor, and carbon dioxide (CO2) during the growing season. Additionally, EC measurements of water vapor and CO2 fluxes from an aircraft platform complemented the tower-based measurements. Sensible heat, water vapor, and CO2 fluxes showed the greatest spatial and temporal variability during the early crop growth stage. Differences in all of the energy balance components were detectable between corn and soybean as well as within similar crops throughout the study period. Tower network–averaged fluxes of sensible heat, water vapor, and CO2 were observed to be in good agreement with area-averaged aircraft flux measurements

    Piperazinyl quinolines as chemosensitizers to increase fluconazole susceptibility of Candida albicans clinical isolates

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    The effectiveness of the potent antifungal drug fluconazole is being compromised by the rise of drug-resistant fungal pathogens. While inhibition of Hsp90 or calcineurin can reverse drug resistance in Candida, such inhibitors also impair the homologous human host protein and fungal-selective chemosensitizers remain rare. The MLPCN library was screened to identify compounds that selectively reverse fluconazole resistance in a Candida albicans clinical isolate, while having no antifungal activity when administered as a single agent. A piperazinyl quinoline was identified as a new small-molecule probe (ML189) satisfying these criteria.National Institutes of Health (U.S.) (1 R03 MH086456-01

    Acupuncture for pain and osteoarthritis of the knee: a pilot study for an open parallel-arm randomised controlled trial

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    <p>Abstract</p> <p>Background</p> <p>There is some evidence that acupuncture for pain and osteoarthritis (OA) of the knee is more than a placebo, and short term clinical benefits have been observed when acupuncture is compared to usual care. However there is insufficient evidence on whether clinical benefits of acupuncture are sustained over the longer term. In this study our key objectives are to inform the design parameters for a fully powered pragmatic randomised controlled trial. These objectives include establishing potential recruitment rates, appropriate validated outcome measures, attendance levels for acupuncture treatment, loss to follow up and the sample size for a full scale trial.</p> <p>Methods</p> <p>Potential participants aged over 50 with pain and osteoarthritis of the knee were identified from a GP database. Eligible patients were randomised to either 'acupuncture plus usual care' and 'usual care' alone, with allocation appropriately concealed. Acupuncture consisted of up to 10 sessions usually weekly. Outcome measures included Western Ontario and McMaster Universities (WOMAC) index with the sample size for a full scale trial determined from the variance.</p> <p>Results</p> <p>From the GP database of 15,927 patients, 335 potential trial participants were identified and invited to participate. After screening responses, 78 (23%) were identified as eligible and 30 patients who responded most promptly were randomised to 'acupuncture plus usual care' (15 patients) and 'usual care' alone (15 patients). Attendance for acupuncture appointments was high at 90% of the maximum. Although the trial was not powered to detect significant changes in outcome, the WOMAC pain index showed a statistically significant reduction at 3 months in the acupuncture group compared to usual care. This was not sustained at 12 months. The sample size for a fully powered two-arm trial was estimated to be 350.</p> <p>Conclusion</p> <p>This pilot study provided the evidence that a fully powered study to explore the longer term impact of acupuncture would be worthwhile, and relevant design features for such a trial were determined.</p> <p>Trial registration number</p> <p>ISRCTN25134802.</p

    Cytokine profile and induction of T helper type 17 and regulatory T cells by human peripheral mononuclear cells after microbial exposure

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    The immunomodulatory effects of probiotics were assessed following exposure of normal peripheral blood mononuclear cells (PBMC), cord blood cells and the spleen-derived monocyte/macrophage cell line CRL-9850 to Lactobacillus acidophilus LAVRI-A1, Lb. rhamnosus GG, exopolysaccharides (EPS)-producing Streptococcus thermophilus St1275, Bifidobacteriun longum BL536, B. lactis B94 and Escherichia coli TG1 strains. The production of a panel of pro- and anti-inflammatory cytokines by PBMC following bacterial stimulation was measured, using live, heat-killed or mock gastrointestinal tract (GIT)-exposed bacteria, and results show that (i) all bacterial strains investigated induced significant secretion of pro- and anti-inflammatory cytokines from PBMC-derived monocytes/macrophages; and (ii) cytokine levels increased relative to the expansion of bacterial cell numbers over time for cells exposed to live cultures. Bifidobacteria and S. thermophilus stimulated significant concentrations of transforming growth factor (TGF)-β, an interleukin necessary for the differentiation of regulatory T cells (Treg)/T helper type 17 (Th17) cells and, as such, the study further examined the induction of Th17 and Treg cells after PBMC exposure to selected bacteria for 96 h. Data show a significant increase in the numbers of both cell types in the exposed populations, measured by cell surface marker expression and by cytokine production. Probiotics have been shown to induce cytokines from a range of immune cells following ingestion of these organisms. These studies suggest that probiotics' interaction with immune-competent cells produces a cytokine milieu, exerting immunomodulatory effects on local effector cells, as well as potently inducing differentiation of Th17 and Treg cells

    Cryptic Distant Relatives Are Common in Both Isolated and Cosmopolitan Genetic Samples

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    Although a few hundred single nucleotide polymorphisms (SNPs) suffice to infer close familial relationships, high density genome-wide SNP data make possible the inference of more distant relationships such as 2nd to 9th cousinships. In order to characterize the relationship between genetic similarity and degree of kinship given a timeframe of 100–300 years, we analyzed the sharing of DNA inferred to be identical by descent (IBD) in a subset of individuals from the 23andMe customer database (n = 22,757) and from the Human Genome Diversity Panel (HGDP-CEPH, n = 952). With data from 121 populations, we show that the average amount of DNA shared IBD in most ethnolinguistically-defined populations, for example Native American groups, Finns and Ashkenazi Jews, differs from continentally-defined populations by several orders of magnitude. Via extensive pedigree-based simulations, we determined bounds for predicted degrees of relationship given the amount of genomic IBD sharing in both endogamous and ‘unrelated’ population samples. Using these bounds as a guide, we detected tens of thousands of 2nd to 9th degree cousin pairs within a heterogenous set of 5,000 Europeans. The ubiquity of distant relatives, detected via IBD segments, in both ethnolinguistic populations and in large ‘unrelated’ populations samples has important implications for genetic genealogy, forensics and genotype/phenotype mapping studies

    Workforce capacity to address obesity: a Western Australian cross-sectional study identifies the gap between health priority and human resources needed

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    Background: The disease burden due to poor nutrition, physical inactivity and obesity is high and increasing. An adequately sized and skilled workforce is required to respond to this issue. This study describes the public health nutrition and physical activity (NAPA) practice priorities and explores health managers and practitioner’s beliefs regarding workforce capacity to deliver on these priorities. Methods: A workforce audit was conducted including a telephone survey of all managers and a postal survey of practitioners working in the area of NAPA promotion in Western Australia in 2004. Managers gave their perspective on workforce priorities, current competencies and future needs, with a 70 % response rate. Practitioners reported on public health workforce priorities, qualifications and needs, with a 56 % response rate. Results: The top practice priorities for managers were diabetes (35 %), alcohol and other drugs (33 %), and cardiovascular disease (27 %). Obesity (19 %), poor nutrition (15 %) and inadequate physical activity (10 %) were of lower priority. For nutrition, managers identified lack of staff (60.4 %), organisational and management factors (39.5 %) and insufficient financial resources (30.2 %) as the major barriers to adequate service delivery. For physical activity services, insufficient financial resources (41.7 %) and staffing (35.4 %) and a lack of specific physical activity service specifications (25.0 %) were the main barriers. Practitioners identified inadequate staffing as the main barrier to service delivery for nutrition (42.3 %) and physical activity (23.3 %). Ideally, managers said they required 152 % more specialist nutritionists in the workforce and 131 % specialists for physical activity services to meet health outcomes in addition to other generalist staff. Conclusion: Human and financial resources and organisational factors were the main barriers to meeting obesity, and public health nutrition and physical activity outcomes. Services were being delivered by generalists rather than specialists, which may reduce service effectiveness. Although conclusions from this research need to take into account the fact that the audit was conducted in 2004, the findings suggest that there was a need to equip health services with an adequately skilled workforce of sufficient capacity to deliver an effective public health response to the obesity epidemic, particularly addressing poor nutrition and physical inactivity

    REFOCUS: developing a recovery focus in mental health services in England

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    Background: Recovery in mental health services is defined as living a satisfying, hopeful, and contributing life even with any limitations caused by illness. An evidence base for understanding and supporting recovery is needed.Objectives: To carry out a programme of linked research studies to understand how mental health services can promote recovery.Design: A two phase, mixed methods study. Phase 1 (theory) involved seven systematic reviews (develop a conceptual framework for recovery; establish its cross-cultural validity; develop a recovery practice framework; review measures of recovery measures; recovery support measures; strengths measures; staff understanding of recovery), development and evaluation of three new measures (INSPIRE for recovery support; IOM for individualised measurement of recovery; SAFE for feasibility assessment), evaluation of existing recovery measure (QPR), national survey, three qualitative studies (conceptual framework validation, staff recoveryoriented practice, black service users), and development of a new manualised REFOCUS intervention. Phase 2 involved a two-site cluster randomised controlled trial of the REFOCUS intervention, with a nested secondary outcome study, process and economic evaluation, interrupted time series analysis, sub-group analysis of black service users, and outcomes comparison. The impact of PPI on the programme was also empirically evaluated.Setting: Six mental health Trusts in England.Participants: 741 community mental health service users, 1,169 mental health staff and 54 expert stakeholders.Interventions: The manualised team-level REFOCUS intervention to increase support for personal recovery.Main outcome measures: Survey: Recovery Self Assessment (RSA). Trial: Questionnaire about the Process of Recovery (QPR), Client Satisfaction Questionnaire (CSQ).Results: Phase 1: the conceptual framework for recovery identified characteristics, stages and processes of recovery. It was cross-culturally valid and applicable to current service users. The recovery practice framework identified four domains of recovery support. INSPIRE, SAFE and IOM were developed and evaluated. The national survey identified differences between team managers (n=22), workers (n=120) and service users (n=108), and found higher recovery orientation was associated with improved recovery. The REFOCUS intervention has two elements: recovery promoting relationships and working practices. Phase 2: the 27-team trial involving 403 service users (297 at follow-up) showed no differences on primary outcomes of QPR (adjusted difference 0.63, 95%CI: -1.4 to 2.3, p=.55), but secondary outcomes of functioning (adjusted difference 5.90, 95%CI 2.6 to 9.2,
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