395 research outputs found

    Analysis of Soil and Groundwater Microbial Population Dynamics at in situ Bioremediation Sites in California and Texas

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    Traditional methods for assessing in situ microbial communities often provide limited information on substrate utilization in bioremediation processes. The goal of this research was to assess new methods for describing the microbial communities found in the groundwater and affected contaminated soils documenting changes in community structure, population dynamics, substrate utilization and biodegradation of constituents of concern (CoC) during a site remediation. Two in situ bioremediation pilot studies using biological plugs are being conducted, one in the California San Francisco Bay Area (Sunnyvale) and one in the East Texas Piney Woods (Longhorn). The hypothesis is that changes in community structure, population dynamics, substrate utilization and biodegradation of CoC will be successfully described by EcoPlate™ and MicroPlate™ (Biolog, LLC) assays, population counts, and MicroTox® acute toxicity tests. Chlorinated aliphatic hydrocarbon and heterotroph plate counts were used to find the number of colony-forming units. The biological plugs successfully introduced chlorinated aliphatic degrading microorganisms to affected areas. At the Sunnyvale site, the average colony forming unit (CFU)/ml tracked reductions in CoC from August 2012 through January 2014. Reductions in CoC, in particular, trichloroethylene (TCE), were seen over a defined time frame of months to years for Sunnyvale. There was a correlation among increased microbial species diversity and abundance and decreased CoC. The average well color development (AWCD) maximum value increased almost 10 fold, the functional diversity and Shannon-Weaver index values showed notable improvement, and the carbon substrate utilization did not show major changes across all monitoring wells on site. At the Longhorn site, the average CFU/ml varied in population totals providing no clear indication of CoC reduction. Plate counts decreased initially but then started to rise again. The number of samples with a high functional diversity and AWCD also increased. Unfortunately, more samples showed a zero for the Shannon-Weaver index. Carbon substrate utilization showed modest improvement. Since the Longhorn site has been in operation for only 1.5 years compared to Sunnyvale’s 5 years, a clearer picture of Sunnyvale’s improvement may be seen. Assays provided correlated assessment of community viability and functionality for both sites

    Tacit knowledge, learning and expertise in dry stone walling

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    This is a detailed study of learning in the context of dry stone walling. It examines what happens in the learning situation. The aim of this work was: 'To understand the nature of expertise in dry stone walling, how it is understood by those practising the craft, and how it is transmitted to others'. The main research questions were, therefore: What happens when dry stone wallers are learning their craft? How do they acquire expertise in dry stone walling? How is this learning communicated? This process necessitated developing a way of engaging with the practitioners, eliciting descriptive data about what they were doing, and why they were doing it, through interviews (or conversations) with both individuals and groups, whilst they practiced their skill. Twenty three wailers were interviewed as they worked, building walls. The material obtained was analysed under seven different themes: 'Knowing how' The use of tacit knowledge or intuition 'Flow' Constant decision making, reflection and learning from mistakes Individual and subjective variations and experiences The relevance of emotion The use of 'rules of thumb' or maxims. Learning walling does not fit simply into any of the seven themes. It is contextualised, complex and individual. It demonstrates tacit knowledge and intuition. It involves emotion, sometimes consciously, sometimes not. It involves memory, problem solving, and learning from mistakes, and reflection. Maxims or 'rules of thumb' were a key element in the learning process at all stages. Linear stages of learning were not evidenced. Deep understanding of the practice is evidenced, and the wider learning and teaching implications are explored.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Spindle Checkpoint Protein Dynamics at Kinetochores in Living Cells

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    BACKGROUND: To test current models for how unattached and untense kinetochores prevent Cdc20 activation of the anaphase-promoting complex/cyclosome (APC/C) throughout the spindle and the cytoplasm, we used GFP fusions and live-cell imaging to quantify the abundance and dynamics of spindle checkpoint proteins Mad1, Mad2, Bub1, BubR1, Mps1, and Cdc20 at kinetochores during mitosis in living PtK2 cells. RESULTS: Unattached kinetochores in prometaphase bound on average only a small fraction (estimated at 500-5000 molecules) of the total cellular pool of each spindle checkpoint protein. Measurements of fluorescence recovery after photobleaching (FRAP) showed that GFP-Cdc20 and GFP-BubR1 exhibit biphasic exponential kinetics at unattached kinetochores, with approximately 50% displaying very fast kinetics (t1/2 of approximately 1-3 s) and approximately 50% displaying slower kinetics similar to the single exponential kinetics of GFP-Mad2 and GFP-Bub3 (t1/2 of 21-23 s). The slower phase of GFP-Cdc20 likely represents complex formation with Mad2 since it was tension insensitive and, unlike the fast phase, it was absent at metaphase kinetochores that lack Mad2 but retain Cdc20 and was absent at unattached prometaphase kinetochores for the Cdc20 derivative GFP-Cdc20delta1-167, which lacks the major Mad2 binding domain but retains kinetochore localization. GFP-Mps1 exhibited single exponential kinetics at unattached kinetochores with a t1/2 of approximately 10 s, whereas most GFP-Mad1 and GFP-Bub1 were much more stable components. CONCLUSIONS: Our data support catalytic models of checkpoint activation where Mad1 and Bub1 are mainly resident, Mad2 free of Mad1, BubR1 and Bub3 free of Bub1, Cdc20, and Mps1 dynamically exchange as part of the diffuse wait-anaphase signal; and Mad2 interacts with Cdc20 at unattached kinetochores

    Spindle Checkpoint Protein Dynamics at Kinetochores in Living Cells

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    BACKGROUND: To test current models for how unattached and untense kinetochores prevent Cdc20 activation of the anaphase-promoting complex/cyclosome (APC/C) throughout the spindle and the cytoplasm, we used GFP fusions and live-cell imaging to quantify the abundance and dynamics of spindle checkpoint proteins Mad1, Mad2, Bub1, BubR1, Mps1, and Cdc20 at kinetochores during mitosis in living PtK2 cells. RESULTS: Unattached kinetochores in prometaphase bound on average only a small fraction (estimated at 500-5000 molecules) of the total cellular pool of each spindle checkpoint protein. Measurements of fluorescence recovery after photobleaching (FRAP) showed that GFP-Cdc20 and GFP-BubR1 exhibit biphasic exponential kinetics at unattached kinetochores, with approximately 50% displaying very fast kinetics (t1/2 of approximately 1-3 s) and approximately 50% displaying slower kinetics similar to the single exponential kinetics of GFP-Mad2 and GFP-Bub3 (t1/2 of 21-23 s). The slower phase of GFP-Cdc20 likely represents complex formation with Mad2 since it was tension insensitive and, unlike the fast phase, it was absent at metaphase kinetochores that lack Mad2 but retain Cdc20 and was absent at unattached prometaphase kinetochores for the Cdc20 derivative GFP-Cdc20delta1-167, which lacks the major Mad2 binding domain but retains kinetochore localization. GFP-Mps1 exhibited single exponential kinetics at unattached kinetochores with a t1/2 of approximately 10 s, whereas most GFP-Mad1 and GFP-Bub1 were much more stable components. CONCLUSIONS: Our data support catalytic models of checkpoint activation where Mad1 and Bub1 are mainly resident, Mad2 free of Mad1, BubR1 and Bub3 free of Bub1, Cdc20, and Mps1 dynamically exchange as part of the diffuse wait-anaphase signal; and Mad2 interacts with Cdc20 at unattached kinetochores

    Benefits of Incentives for Breastfeeding and Smoking cessation in pregnancy (BIBS): a mixed-methods study to inform trial design

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    Background: Smoking in pregnancy and/or not breastfeeding have considerable negative health outcomes for mother and baby. Aim: To understand incentive mechanisms of action for smoking cessation in pregnancy and breastfeeding, develop a taxonomy and identify promising, acceptable and feasible interventions to inform trial design. Design: Evidence syntheses, primary qualitative survey, and discrete choice experiment (DCE) research using multidisciplinary, mixed methods. Two mother-and-baby groups in disadvantaged areas collaborated throughout. Setting: UK. Participants: The qualitative study included 88 pregnant women/recent mothers/partners, 53 service providers, 24 experts/decision-makers and 63 conference attendees. The surveys included 1144 members of the general public and 497 health professionals. The DCE study included 320 women with a history of smoking. Methods: (1) Evidence syntheses: incentive effectiveness (including meta-analysis and effect size estimates), delivery processes, barriers to and facilitators of smoking cessation in pregnancy and/or breastfeeding, scoping review of incentives for lifestyle behaviours; (2) qualitative research: grounded theory to understand incentive mechanisms of action and a framework approach for trial design; (3) survey: multivariable ordered logit models; (4) DCE: conditional logit regression and the log-likelihood ratio test. Results: Out of 1469 smoking cessation and 5408 breastfeeding multicomponent studies identified, 23 smoking cessation and 19 breastfeeding studies were included in the review. Vouchers contingent on biochemically proven smoking cessation in pregnancy were effective, with a relative risk of 2.58 (95% confidence interval 1.63 to 4.07) compared with non-contingent incentives for participation (four studies, 344 participants). Effects continued until 3 months post partum. Inconclusive effects were found for breastfeeding incentives compared with no/smaller incentives (13 studies) but provider commitment contracts for breastfeeding show promise. Intervention intensity is a possible confounder. The acceptability of seven promising incentives was mixed. Women (for vouchers) and those with a lower level of education (except for breastfeeding incentives) were more likely to disagree. Those aged ≤ 44 years and ethnic minority groups were more likely to agree. Agreement was greatest for a free breast pump and least for vouchers for breastfeeding. Universal incentives were preferred to those targeting low-income women. Initial daily text/telephone support, a quitting pal, vouchers for > £20.00 per month and values up to £80.00 increase the likelihood of smoking cessation. Doctors disagreed with provider incentives. A ‘ladder’ logic model emerged through data synthesis and had face validity with service users. It combined an incentive typology and behaviour change taxonomy. Autonomy and well-being matter. Personal difficulties, emotions, socialising and attitudes of others are challenges to climbing a metaphorical ‘ladder’ towards smoking cessation and breastfeeding. Incentive interventions provide opportunity ‘rungs’ to help, including regular skilled flexible support, a pal, setting goals, monitoring and outcome verification. Individually tailored and non-judgemental continuity of care can bolster women’s capabilities to succeed. Rigid, prescriptive interventions placing the onus on women to behave ‘healthily’ risk them feeling pressurised and failing. To avoid ‘losing face’, women may disengage. Limitations: Included studies were heterogeneous and of variable quality, limiting the assessment of incentive effectiveness. No cost-effectiveness data were reported. In surveys, selection bias and confounding are possible. The validity and utility of the ladder logic model requires evaluation with more diverse samples of the target population. Conclusions: Incentives provided with other tailored components show promise but reach is a concern. Formal evaluation is recommended. Collaborative service-user involvement is importan

    Gravitational Wave Experiments and Early Universe Cosmology

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    Gravitational-wave experiments with interferometers and with resonant masses can search for stochastic backgrounds of gravitational waves of cosmological origin. We review both experimental and theoretical aspects of the search for these backgrounds. We give a pedagogical derivation of the various relations that characterize the response of a detector to a stochastic background. We discuss the sensitivities of the large interferometers under constructions (LIGO, VIRGO, GEO600, TAMA300, AIGO) or planned (Avdanced LIGO, LISA) and of the presently operating resonant bars, and we give the sensitivities for various two-detectors correlations. We examine the existing limits on the energy density in gravitational waves from nucleosynthesis, COBE and pulsars, and their effects on theoretical predictions. We discuss general theoretical principles for order-of-magnitude estimates of cosmological production mechanisms, and then we turn to specific theoretical predictions from inflation, string cosmology, phase transitions, cosmic strings and other mechanisms. We finally compare with the stochastic backgrounds of astrophysical origin.Comment: 99 pages, Latex, 17 figures. To appear in Physics Report. v4: conceptual changes in sect. 7.

    A primary care, multi-disciplinary disease management program for opioid-treated patients with chronic non-cancer pain and a high burden of psychiatric comorbidity

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    BACKGROUND: Chronic non-cancer pain is a common problem that is often accompanied by psychiatric comorbidity and disability. The effectiveness of a multi-disciplinary pain management program was tested in a 3 month before and after trial. METHODS: Providers in an academic general medicine clinic referred patients with chronic non-cancer pain for participation in a program that combined the skills of internists, clinical pharmacists, and a psychiatrist. Patients were either receiving opioids or being considered for opioid therapy. The intervention consisted of structured clinical assessments, monthly follow-up, pain contracts, medication titration, and psychiatric consultation. Pain, mood, and function were assessed at baseline and 3 months using the Brief Pain Inventory (BPI), the Center for Epidemiological Studies-Depression Scale scale (CESD) and the Pain Disability Index (PDI). Patients were monitored for substance misuse. RESULTS: Eighty-five patients were enrolled. Mean age was 51 years, 60% were male, 78% were Caucasian, and 93% were receiving opioids. Baseline average pain was 6.5 on an 11 point scale. The average CESD score was 24.0, and the mean PDI score was 47.0. Sixty-three patients (73%) completed 3 month follow-up. Fifteen withdrew from the program after identification of substance misuse. Among those completing 3 month follow-up, the average pain score improved to 5.5 (p = 0.003). The mean PDI score improved to 39.3 (p < 0.001). Mean CESD score was reduced to 18.0 (p < 0.001), and the proportion of depressed patients fell from 79% to 54% (p = 0.003). Substance misuse was identified in 27 patients (32%). CONCLUSIONS: A primary care disease management program improved pain, depression, and disability scores over three months in a cohort of opioid-treated patients with chronic non-cancer pain. Substance misuse and depression were common, and many patients who had substance misuse identified left the program when they were no longer prescribed opioids. Effective care of patients with chronic pain should include rigorous assessment and treatment of these comorbid disorders and intensive efforts to insure follow up

    Measurement of the Neutron Spin Structure Function g1ng_1^n with a Polarized ^3He Target

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    Results are reported from the HERMES experiment at HERA on a measurement of the neutron spin structure function g1n(x,Q2)g_1^n(x,Q^2) in deep inelastic scattering using 27.5 GeV longitudinally polarized positrons incident on a polarized 3^3He internal gas target. The data cover the kinematic range 0.023<x<0.60.023<x<0.6 and 1(GeV/c)2<Q2<15(GeV/c)21 (GeV/c)^2 < Q^2 <15 (GeV/c)^2. The integral 0.0230.6g1n(x)dx\int_{0.023}^{0.6} g_1^n(x) dx evaluated at a fixed Q2Q^2 of 2.5(GeV/c)22.5 (GeV/c)^2 is 0.034±0.013(stat.)±0.005(syst.)-0.034\pm 0.013(stat.)\pm 0.005(syst.). Assuming Regge behavior at low xx, the first moment Γ1n=01g1n(x)dx\Gamma_1^n=\int_0^1 g_1^n(x) dx is 0.037±0.013(stat.)±0.005(syst.)±0.006(extrapol.)-0.037\pm 0.013(stat.)\pm 0.005(syst.)\pm 0.006(extrapol.).Comment: 4 pages TEX, text available at http://www.krl.caltech.edu/preprints/OAP.htm
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