932 research outputs found

    The energetic consequence of specific dynamic action in southern bluefin tuna Thunnus maccoyii

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    Copyright © 2007 The Company of BiologistsThe effect of feeding on the rate of oxygen consumption (O2) of four groups of three southern bluefin tuna Thunnus maccoyii (SBT) was examined in a large static respirometer at water temperatures of 18.2-20.3°C. Six feeding events of rations between 2.1-8.5% body mass (%Mb) of Australian sardines (Sardinops neopilchardus) were recorded (two of the groups were fed twice). Before feeding, fish swam between 0.71 and 1.4 body lengths s-1 (BL s-1) and the routine metabolic rate (RMR) was 366±32.5 mg kg-1 h-1 (mean ± s.e.m.). For all trials, O2 was elevated post feeding, presumably as a result of specific dynamic action (SDA). Swimming velocity was also elevated post feeding for periods similar to that of O2 (between 20-45 h, longest for the largest rations). Post feeding swimming velocity increased to between 0.87-2.6 BL s-1 and was also dependent on ration consumed. It is suggested that the purpose of increased post-feeding swimming velocity was to increase ventilation volume as a response to the enhanced metabolic demand associated with SDA. Peak post-prandial O2 increased linearly with ration size to a maximum of 1290 mg kg-1 h-1, corresponding to 2.8 times the RMR. When converted to its energy equivalent, total magnitude of SDA was linearly correlated with ration size to a maximum of 192 kJ kg-1 h-1, and as a proportion of gross energy ingested (SDA coefficient), it averaged 35±2.2%. These results demonstrate that, although the factorial increase of SDA in SBT is similar to that of other fish species, the absolute energetic cost of SDA is much higher. These results support the contention that tuna are energy speculators, gambling high rates of energy expenditure for potentially higher rates of energy returns. The ration that southern bluefin tuna require to equal the combined metabolic costs of SDA and RMR is estimated in this study to be 3.5%Mb of Australian sardines per day.Q. P. Fitzgibbon, R. S. Seymour, D. Ellis and J. Buchana

    New results on GP Com

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    We present high resolution optical and UV spectra of the 46 min orbital period, helium binary, GP Com. Our data contains simultaneous photometric correction which confirms the flaring behaviour observed in previous optical and UV data. In this system all lines show a triple peaked structure where the outer two peaks are associated with the accretion disc around the compact object. The main aim of this paper is to constrain the origin of the central peak, also called ``central spike''. We find that the central spike contributes to the flare spectra indicating that its origin is probably the compact object. We also detect that the central spike moves with orbital phase following an S-wave pattern. The radial velocity semiamplitude of the S-wave is ~10 km/s indicating that its origin is near the centre of mass of the system, which in this case lies very close to the white dwarf. Our resolution is higher than that of previous data which allows us to resolve structure in the central peak of the line. The central spike in three of the HeI lines shows another peak blueshifted with respect to the main peak. We propose that one of the peaks is a neutral helium forbidden transition excited in a high electron density region. This forbidden transition is associated with the permitted one (the stronger peak in two of the lines). The presence of a high electron density region again favours the white dwarf as their origin.Comment: 14 pages, 16 figures. Accepted for publication in A&

    Drug ranking using machine learning systematically predicts the efficacy of anti-cancer drugs

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    Artificial intelligence and machine learning (ML) promise to transform cancer therapies by accurately predicting the most appropriate therapies to treat individual patients. Here, we present an approach, named Drug Ranking Using ML (DRUML), which uses omics data to produce ordered lists of >400 drugs based on their anti-proliferative efficacy in cancer cells. To reduce noise and increase predictive robustness, instead of individual features, DRUML uses internally normalized distance metrics of drug response as features for ML model generation. DRUML is trained using in-house proteomics and phosphoproteomics data derived from 48 cell lines, and it is verified with data comprised of 53 cellular models from 12 independent laboratories. We show that DRUML predicts drug responses in independent verification datasets with low error (mean squared error < 0.1 and mean Spearman’s rank 0.7). In addition, we demonstrate that DRUML predictions of cytarabine sensitivity in clinical leukemia samples are prognostic of patient survival (Log rank p < 0.005). Our results indicate that DRUML accurately ranks anti-cancer drugs by their efficacy across a wide range of pathologies

    Society of Behavior Medicine (SBM) Urges Congress to Ensure Affordable Care Act Coverage of Prostate Cancer Screening Support Services for High-Risk Men

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    © Society of Behavioral Medicine 2019. All rights reserved. For permissions, please e-mail: [email protected]. Prostate cancer (PCa) disproportionately affects African American men. Early detection reduces risk of mortality. The United States Preventive Services Task Force (USPSTF) issued an updated recommendation statement on serum Prostate Specific Antigen (PSA)-based screening for PCa. Specifically, in 2012, the USPSTF recommended against PSA-based screening due to risk for overdiagnosis and overtreatment. However, the updated 2018 guidelines recommend consideration of screening for certain at risk men and revised the recommendation rating from D to C. This new guideline recommends providers to educate high-risk men on the benefits and harms of PSA-based PCa screening so that they can make an informed decision. The Affordable Care Act (ACA) includes provisions of service coverage for patient navigators who can help patients decide whether screening is appropriate, given potential risks and benefits, and training of health care providers in shared-decision regarding screening/treatment. These services can be utilized to support health care providers to better adhere to the new guideline. However, recommendations that are given a C rating or lower are not consistently reimbursed through many plans, including those offered through the ACA marketplace. The Society of Behavioral Medicine (SBM) supports the USPSTF guideline for the consideration of prostate cancer screening for high-risk men between the ages of 55 and 69. SBM encourages policymakers to include provisions for coverage of patient navigation services in the ACA to facilitate shared decision-making between providers and patients regarding screening

    Enhancing the early student experience

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    This paper is concerned with identifying how the early student experience can be enhanced in order to improve levels of student retention and achievement. The early student experience is the focus of this project as the literature has consistently declared the first year to be the most critical in shaping persistence decisions. Programme managers of courses with high and low retention rates have been interviewed to identify activities that appear to be associated with good retention rates. The results show that there are similarities in the way programmes with high retention are run, with these features not being prevalent on programmes with low retention. Recommendations of activities that appear likely to enhance the early student experience are provided

    Quantification of Extracellular DNA Network Abundance and Architecture within Streptococcus gordonii Biofilms Reveals Modulatory Factors

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    Extracellular DNA (eDNA) is an important component of biofilm matrix that serves to maintain biofilm structural integrity, promotes genetic exchange within the biofilm, and provides protection against antimicrobial compounds. Advances in microscopy techniques have provided evidence of the cobweb- or lattice-like structures of eDNA within biofilms from a range of environmental niches. However, methods to reliably assess the abundance and architecture of eDNA remain lacking. This study aimed to address this gap by development of a novel, high-throughput image acquisition and analysis platform for assessment of eDNA networks in situ within biofilms. Utilizing Streptococcus gordonii as the model, the capacity for this imaging system to reliably detect eDNA networks and monitor changes in abundance and architecture (e.g., strand length and branch number) was verified. Evidence was provided of a synergy between glucans and eDNA matrices, while it was revealed that surface-bound nuclease SsnA could modify these eDNA structures under conditions permissive for enzymatic activity. Moreover, cross talk between the competence and hexaheptapeptide permease systems was shown to regulate eDNA release by S. gordonii. This novel imaging system can be applied across the wider field of biofilm research, with potential to significantly advance interrogation of the mechanisms by which the eDNA network architecture develops, how it can influence biofilm properties, and how it may be targeted for therapeutic benefit. IMPORTANCE Extracellular DNA (eDNA) is critical for maintaining the structural integrity of many microbial biofilms, making it an attractive target for the management of biofilms. However, our knowledge and targeting of eDNA are currently hindered by a lack of tools for the quantitative assessment of eDNA networks within biofilms. Here, we demonstrate use of a novel image acquisition and analysis platform with the capacity to reliably monitor the abundance and architecture of eDNA networks. Application of this tool to Streptococcus gordonii biofilms has provided new insights into how eDNA networks are stabilized within the biofilm and the pathways that can regulate eDNA release. This highlights how exploitation of this novel imaging system across the wider field of biofilm research has potential to significantly advance interrogation of the mechanisms by which the eDNA network architecture develops, how it can influence biofilm properties, and how it may be targeted for therapeutic benefit

    Overcoming barriers to engaging socio-economically disadvantaged populations in CHD primary prevention: a qualitative study

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    &lt;p&gt;&lt;b&gt;Background:&lt;/b&gt; Preventative medicine has become increasingly important in efforts to reduce the burden of chronic disease in industrialised countries. However, interventions that fail to recruit socio-economically representative samples may widen existing health inequalities. This paper explores the barriers and facilitators to engaging a socio-economically disadvantaged (SED) population in primary prevention for coronary heart disease (CHD).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods:&lt;/b&gt; The primary prevention element of Have a Heart Paisley (HaHP) offered risk screening to all eligible individuals. The programme employed two approaches to engaging with the community: a) a social marketing campaign and b) a community development project adopting primarily face-to-face canvassing. Individuals living in areas of SED were under-recruited via the social marketing approach, but successfully recruited via face-to-face canvassing. This paper reports on focus group discussions with participants, exploring their perceptions about and experiences of both approaches.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Results:&lt;/b&gt; Various reasons were identified for low uptake of risk screening amongst individuals living in areas of high SED in response to the social marketing campaign and a number of ways in which the face-to-face canvassing approach overcame these barriers were identified. These have been categorised into four main themes: (1) processes of engagement; (2) issues of understanding; (3) design of the screening service and (4) the priority accorded to screening. The most immediate barriers to recruitment were the invitation letter, which often failed to reach its target, and the general distrust of postal correspondence. In contrast, participants were positive about the face-to-face canvassing approach. Participants expressed a lack of knowledge and understanding about CHD and their risk of developing it and felt there was a lack of clarity in the information provided in the mailing in terms of the process and value of screening. In contrast, direct face-to-face contact meant that outreach workers could explain what to expect. Participants felt that the procedure for uptake of screening was demanding and inflexible, but that the drop-in sessions employed by the community development project had a major impact on recruitment and retention.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusion:&lt;/b&gt; Socio-economically disadvantaged individuals can be hard-to-reach; engagement requires strategies tailored to the needs of the target population rather than a population-wide approach.&lt;/p&gt

    Euclidean Structure from N>=2 Parallel Circles: Theory and Algorithms

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    International audienceOur problem is that of recovering, in one view, the 2D Euclidean structure, induced by the projections of N parallel circles. This structure is a prerequisite for camera calibration and pose computation. Until now, no general method has been described for N > 2. The main contribution of this work is to state the problem in terms of a system of linear equations to solve.We give a closed-form solution as well as bundle adjustment-like refinements, increasing the technical applicability and numerical stability. Our theoretical approach generalizes and extends all those described in existing works for N = 2 in several respects, as we can treat simultaneously pairs of orthogonal lines and pairs of circles within a unified framework. The proposed algorithm may be easily implemented, using well-known numerical algorithms. Its performance is illustrated by simulations and experiments with real images
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