4,546 research outputs found

    Hemolytic activity of adenylate cyclase toxin fromBordetella pertussis

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    AbstractAdenylate cyclase (AC) toxin fromB. pertussis enters eukaryotic cells where it produces supraphysiologie levels of cAMP. Purification of AC toxin activity [(1989) J. Biol. Chem. 264, 19279] results in increasing potency of hemolytic activity and electroelution of the 216-kDA holotoxin yields a single protein with AC enzymatic, toxin and hemolytic activities. AC toxin andE. coli hemolysin, which have DNA sequence homology [(1988) EMBO J. 7, 3997] are immunologically cross-reactive. The time courses of hemolysis elicited by the two molecules are strikingly different, however, with AC toxin eliciting cAMP accumulation with rapid onset, but hemolysis with a lag of ≥ 45 min. Finally, osmotic protection experiments indicate that the size of the putative pore produced by AC toxin is 3 5-fold smaller than that ofE. coli hemolysin

    Randomised controlled trial of the clinical and cost-effectiveness of a peer delivered self-management intervention to prevent relapse in crisis resolution team users: study protocol

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    Introduction: Crisis resolution teams (CRTs) provide assessment and intensive home treatment in a crisis, aiming to offer an alternative for people who would otherwise require a psychiatric inpatient admission. They are available in most areas in England. Despite some evidence for their clinical and cost-effectiveness, recurrent concerns are expressed regarding discontinuity with other services and lack of focus on preventing future relapse and readmission to acute care. Currently evidence on how to prevent readmissions to acute care is limited. Self management interventions, involving supporting service users in recognising and managing signs of their own illness and in actively planning their recovery, have some supporting evidence, but have not been tested as a means of preventing readmission to acute care in people leaving community crisis care. We thus proposed the current study to test the effectiveness of such an intervention. We selected peer support workers as the preferred staff to deliver such an intervention, as they are well-placed to model and encourage active and autonomous recovery from mental health problems. Methods and analysis: The CORE (CRT Optimisation and Relapse Prevention) self management trial compares the effectiveness of a peer provided self-management intervention for people leaving CRT care, with treatment as usual supplemented by a booklet on self-management. The planned sample is 440 participants, including 40 participants in an internal pilot. The primary outcome measure is whether participants are readmitted to acute care over 1 year of follow-up following entry to the trial. Secondary outcomes include self-rated recovery at 4 and at 18 months following trial entry, measured using the Questionnaire on the Process of Recovery. Analysis will follow an intention to treatment principle. Random effects logistic regression modelling with adjustment for clustering by peer support worker will be used to test the primary hypothesis

    WESTT (Workload, Error, Situational Awareness, Time and Teamwork): An analytical prototyping system for command and control

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    Modern developments in the use of information technology within command and control allow unprecedented scope for flexibility in the way teams deal with tasks. These developments, together with the increased recognition of the importance of knowledge management within teams present difficulties for the analyst in terms of evaluating the impacts of changes to task composition or team membership. In this paper an approach to this problem is presented that represents team behaviour in terms of three linked networks (representing task, social network structure and knowledge) within the integrative WESTT software tool. In addition, by automating analyses of workload and error based on the same data that generate the networks, WESTT allows the user to engage in the process of rapid and iterative “analytical prototyping”. For purposes of illustration an example of the use of this technique with regard to a simple tactical vignette is presented

    A national survey of supervised toothbrushing programmes in England

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    Introduction Supervised toothbrushing programmes (STPs) are a cost-effective public health intervention, reducing tooth decay and health inequalities in children. However, the uptake of STPs in England is unknown. This study aimed to establish the current provision of STPs across England and summarise the barriers and facilitators to their implementation. Methods An online survey was sent to dental public health consultants, local authority (LA) oral health leads, and public health practitioners across England. Quantitative data were analysed using descriptive statistics. Barriers and facilitators were analysed using the Consolidated Framework for Implementation Research. Results Information was received for 141 LAs across England. Approximately half implemented an STP (n = 68/141). Most STPs were commissioned by LAs (n = 44/68) and adopted a targeted approach (n = 54/68). Barriers to implementation were: 1) acquiring funding; 2) poor communication and engagement between LAs, oral health providers and settings; 3) oral health not a priority; 4) logistically challenging to implement; and 5) lack of capacity. Facilitators were: 1) an integrated and mandated public health approach; 2) collaboration and ongoing support between LAs, oral health providers, and settings; 3) clarity of guidance; 4) flexible approach to delivery; 5) adequate available resources; and 6) ownership and empowerment of setting staff. Conclusion The current provision of STPs is varied, and although there are challenges to their implementation, there are also areas of good practice where these challenges have been overcome

    Remote Sensing Phenology of Antarctic Green and Red Snow Algae Using WorldView Satellites

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    Snow algae are an important group of terrestrial photosynthetic organisms in Antarctica, where they mostly grow in low lying coastal snow fields. Reliable observations of Antarctic snow algae are difficult owing to the transient nature of their blooms and the logistics involved to travel and work there. Previous studies have used Sentinel 2 satellite imagery to detect and monitor snow algal blooms remotely, but were limited by the coarse spatial resolution and difficulties detecting red blooms. Here, for the first time, we use high-resolution WorldView multispectral satellite imagery to study Antarctic snow algal blooms in detail, tracking the growth of red and green blooms throughout the summer. Our remote sensing approach was developed alongside two Antarctic field seasons, where field spectroscopy was used to build a detection model capable of estimating cell density. Global Positioning System (GPS) tagging of blooms and in situ life cycle analysis was used to validate and verify our model output. WorldView imagery was then used successfully to identify red and green snow algae on Anchorage Island (Ryder Bay, 67°S), estimating peak coverage to be 9.48 × 104 and 6.26 × 104 m2, respectively. Combined, this was greater than terrestrial vegetation area coverage for the island, measured using a normalized difference vegetation index. Green snow algae had greater cell density and average layer thickness than red blooms (6.0 × 104 vs. 4.3 × 104 cells ml−1) and so for Anchorage Island we estimated that green algae dry biomass was over three times that of red algae (567 vs. 180 kg, respectively). Because the high spatial resolution of the WorldView imagery and its ability to detect red blooms, calculated snow algal area was 17.5 times greater than estimated with Sentinel 2 imagery. This highlights a scaling problem of using coarse resolution imagery and suggests snow algal contribution to net primary productivity on Antarctica may be far greater than previously recognized

    Remote sensing reveals Antarctic green snow algae as important terrestrial carbon sink

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    Abstract: We present the first estimate of green snow algae community biomass and distribution along the Antarctic Peninsula. Sentinel 2 imagery supported by two field campaigns revealed 1679 snow algae blooms, seasonally covering 1.95 × 106 m2 and equating to 1.3 × 103 tonnes total dry biomass. Ecosystem range is limited to areas with average positive summer temperatures, and distribution strongly influenced by marine nutrient inputs, with 60% of blooms less than 5 km from a penguin colony. A warming Antarctica may lose a majority of the 62% of blooms occupying small, low-lying islands with no high ground for range expansion. However, bloom area and elevation were observed to increase at lower latitudes, suggesting that parallel expansion of bloom area on larger landmasses, close to bird or seal colonies, is likely. This increase is predicted to outweigh biomass lost from small islands, resulting in a net increase in snow algae extent and biomass as the Peninsula warms

    Quantization and Compressive Sensing

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    Quantization is an essential step in digitizing signals, and, therefore, an indispensable component of any modern acquisition system. This book chapter explores the interaction of quantization and compressive sensing and examines practical quantization strategies for compressive acquisition systems. Specifically, we first provide a brief overview of quantization and examine fundamental performance bounds applicable to any quantization approach. Next, we consider several forms of scalar quantizers, namely uniform, non-uniform, and 1-bit. We provide performance bounds and fundamental analysis, as well as practical quantizer designs and reconstruction algorithms that account for quantization. Furthermore, we provide an overview of Sigma-Delta (ΣΔ\Sigma\Delta) quantization in the compressed sensing context, and also discuss implementation issues, recovery algorithms and performance bounds. As we demonstrate, proper accounting for quantization and careful quantizer design has significant impact in the performance of a compressive acquisition system.Comment: 35 pages, 20 figures, to appear in Springer book "Compressed Sensing and Its Applications", 201

    Ethnic inequalities and pathways to care in psychosis in England: a systematic review and meta-analysis

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    © The Author(s). 2018Background: As part of a national programme to tackle ethnic inequalities, we conducted a systematic review and meta-analysis of research on ethnic inequalities in pathways to care for adults with psychosis living in England and/or Wales. Methods: Nine databases were searched from inception to 03.07.17 for previous systematic reviews, including forward and backward citation tracking and a PROSPERO search to identify ongoing reviews. We then carried forward relevant primary studies from included reviews (with the latest meta-analyses reporting on research up to 2012), supplemented by a search on 18.10.17 in MEDLINE, Embase, PsycINFO and CINAHL for primary studies between 2012 and 2017 that had not been covered by previous meta-analyses. Results: Forty studies, all conducted in England, were included for our updated meta-analyses on pathways to care. Relative to the White reference group, elevated rates of civil detentions were found for Black Caribbean (OR = 3.43, 95% CI = 2.68 to 4.40, n = 18), Black African (OR = 3.11, 95% CI = 2.40 to 4.02, n = 6), and South Asian patients (OR = 1.50, 95% CI 1.07 to 2.12, n = 10). Analyses of each Mental Health Act section revealed significantly higher rates for Black people under (civil) Section 2 (OR = 1.53, 95% CI = 1.11 to 2.11, n = 3). Rates in repeat admissions were significantly higher than in first admission for South Asian patients (between-group difference p < 0.01). Some ethnic groups had more police contact (Black African OR = 3.60, 95% CI = 2.15 to 6.05, n = 2; Black Caribbean OR = 2.64, 95% CI = 1.88 to 3.72, n = 8) and criminal justice system involvement (Black Caribbean OR = 2.76, 95% CI = 2.02 to 3.78, n = 5; Black African OR = 1.92, 95% CI = 1.32 to 2.78, n = 3). The White Other patients also showed greater police and criminal justice system involvement than White British patients (OR = 1.49, 95% CI = 1.03 to 2.15, n = 4). General practitioner involvement was less likely for Black than the White reference group. No significant variations over time were found across all the main outcomes. Conclusions: Our updated meta-analyses reveal persisting but not significantly worsening patterns of ethnic inequalities in pathways to psychiatric care, particularly affecting Black groups. This provides a comprehensive evidence base from which to inform policy and practice amidst a prospective Mental Health Act reform. Trial registration: CRD42017071663Peer reviewedFinal Published versio

    Long-term weight loss following a randomised controlled trial of a weight management programme for men delivered through professional football clubs: the Football Fans in Training follow-up study

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    Background: Rising levels of obesity require interventions that support people in long-term weight loss. The Football Fans in Training (FFIT) programme uses loyalty to football teams to engage men in weight loss. In 2011/12, a randomised controlled trial (RCT) found that the FFIT programme was effective in helping men lose weight up to 12 months. Objectives: To investigate the long-term weight, and other physical, behavioural and psychological outcomes up to 3.5 years after the start of the RCT; the predictors, mediators and men’s qualitative experiences of long-term weight loss; cost-effectiveness; and the potential for long-term follow-up via men’s medical records. Design: A mixed-methods, longitudinal cohort study. Setting: Thirteen professional Scottish football clubs from the RCT and 16 additional Scottish football clubs that delivered the FFIT programme in 2015/16. Participants: A total of 665 men who were aged 35–65 years at the RCT baseline measures and who consented to follow-up after the RCT (intervention group, n = 316; comparison group, n = 349), and 511 men who took part in the 2015/16 deliveries of the FFIT programme. Interventions: None as part of this study. Main outcome measures: Objectively measured weight change from the RCT baseline to 3.5 years. Results: In total, 488 out of 665 men (73.4%) attended 3.5-year measurements. Participants in the FFIT follow-up intervention group sustained a mean weight loss from baseline of 2.90 kg [95% confidence interval (CI) 1.78 to 4.02 kg; p Additional co-authors: Colin McCowan, Alice McLean, Nanette Mutri
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