476 research outputs found

    Teachers Creating Safe School Environments: Prevention of Elementary Student-to-Student Bullying

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    Student-to-student bullying is still a current issue within elementary schools nationwide. Educators are often unaware, improperly trained and/or unwilling to help in student bullying incidences. Without training or willingness, teachers often are driven into silence and inaction, effectively putting the wellbeing of students at risk. The present study examines this topic through previous literature, gathers data to raise further awareness and better understanding of this issue, and provides proactive bullying prevention strategies for teachers. The present study collects data quantitatively and qualitatively with the conduction of surveys and personal interviews of pre-service and veteran educators respectively. Findings reveal increasing efforts to address student bullying, and evidence suggests pre-service and veteran teachers are still underprepared to handle student bullying. There remains ongoing need for further research to provide best methods of bullying prevention for all students involved in order to bring about positive and lasting change

    sscMap: An extensible Java application for connecting small-molecule drugs using gene-expression signatures

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    Background: Connectivity mapping is a process to recognize novel pharmacological and toxicological properties in small molecules by comparing their gene expression signatures with others in a database. A simple and robust method for connectivity mapping with increased specificity and sensitivity was recently developed, and its utility demonstrated using experimentally derived gene signatures. Results: This paper introduces sscMap (statistically significant connections' map), a Java application designed to undertake connectivity mapping tasks using the recently published method. The software is bundled with a default collection of reference gene-expression profiles based on the publicly available dataset from the Broad Institute Connectivity Map 02, which includes data from over 7000 Affymetrix microarrays, for over 1000 small-molecule compounds, and 6100 treatment instances in 5 human cell lines. In addition, the application allows users to add their custom collections of reference profiles and is applicable to a wide range of other 'omics technologies. Conclusions: The utility of sscMap is two fold. First, it serves to make statistically significant connections between a user-supplied gene signature and the 6100 core reference profiles based on the Broad Institute expanded dataset. Second, it allows users to apply the same improved method to custom-built reference profiles which can be added to the database for future referencing. The software can be freely downloaded from http://purl.oclc.org/NET/sscMapComment: 3 pages, 1 table, 1 eps figur

    Experimentation and modelling of near field explosions

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    Repeatable experimental results and numerical work has shown that using the Jones-Wilkins-Lee (JWL) equation of state (EOS) will give very accurate results of peak pressures and impulse delivered to a rigid target at large scaled distances. However, recent experiments/numerical modelling at small scaled distances show that the JWL will overpredict peak pressures and impulse due to the assumption of (near) instantaneous energy release from detonation. The results of this experimental/numerical study are presented herein. In the experimental work PE4 spheres at two different scaled distances have been tested using an array of Hopkinson Pressure Bars (HPB) at specific points on a rigid target to measure the local pressure-time histories. From the HPB measurements, it appears that below certain scaled distances there are chemical-physical mechanisms that do not have sufficient time to contribute to the energy driving the loading mechanisms, explaining the over-prediction of the JWL. Importantly though, the experimental results show that at very small scaled distances (0.172 m/kg1/3) the test to test percentage variation is very low (5.1%); whilst at larger scaled distances (0.819 m/kg1/3) it is much higher (23.1%). This paper presents a model which describes the process by which experimental results move from repeatable to variable to repeatable as scaled distance increases from the extreme near field to far field

    Band gaps of crystalline solids from Wannier-localization based optimal tuning of a screened range-separated hybrid functional

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    Accurate prediction of fundamental band gaps of crystalline solid state systems entirely within density functional theory is a long standing challenge. Here, we present a simple and inexpensive method that achieves this by means of non-empirical optimal tuning of the parameters of a screened range-separated hybrid functional. The tuning involves the enforcement of an ansatz that generalizes the ionization potential theorem to the removal of an electron in an occupied state described by a localized Wannier function in a modestly sized supercell calculation. The method is benchmarked against experiment for a set of systems ranging from narrow band gap semiconductors to large band gap insulators, spanning a range of fundamental band gaps from 0.2 to 14.2 eV and is found to yield quantitative accuracy across the board, with a mean absolute error of \sim0.1 eV and a maximal error of \sim0.2 eV.Comment: 10 pages, 2 figure

    Optical absorption spectra of metal oxides from time-dependent density functional theory and many-body perturbation theory based on optimally-tuned hybrid functionals

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    Using both time-dependent density functional theory (TDDFT) and the ``single-shot" GWGW plus Bethe-Salpeter equation (GWGW-BSE) approach, we compute optical band gaps and optical absorption spectra from first principles for eight common binary and ternary closed-shell metal oxides (MgO, Al2_2O3_3, CaO, TiO2_2, Cu2_2O, ZnO, BaSnO3_3, and BiVO4_4), based on the non-empirical Wannier-localized optimally-tuned screened range-separated hybrid functional. Overall, we find excellent agreement between our TDDFT and GWGW-BSE results and experiment, with a mean absolute error less than 0.4 eV, including for Cu2_2O and ZnO, traditionally considered to be challenging for both methods

    Finite element simulation of plates under non-uniform blast loads using a point-load method: Buried explosives

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    There are two primary challenges associated with assessing the adequacy of a protective structure to resist explosive events: firstly the spatial variation of load acting on a target must be predicted to a sufficient level of accuracy; secondly, the response of the target to this load must also be quantified. When a high explosive is shallowly buried in soil, the added confinement given by the geotechnical material results in a blast which is predominantly directed vertically. This imparts an extremely high magnitude, spatially non-uniform load on the target structure. A recently commissioned experimental rig designed by the authors has enabled direct measurements of the blast load resulting from buried explosive events. These direct measurements have been processed using an in-house interpolation routine which evaluates the load acting over a regular grid of points. These loads can then be applied as the nodal-point loads in a finite element model. This paper presents results from a series of experiments where a free-flying plate was suspended above a shallow buried explosive. Dynamic and residual deformations are compared with finite element simulations of plates using the experimentally recorded, and interpolated, nodal point-loads. The results show very good agreement and highlight the use of this method for evaluating the efficacy of targets subjected to non-uniform blast loads

    A simple and robust method for connecting small-molecule drugs using gene-expression signatures

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    Interaction of a drug or chemical with a biological system can result in a gene-expression profile or signature characteristic of the event. Using a suitably robust algorithm these signatures can potentially be used to connect molecules with similar pharmacological or toxicological properties. The Connectivity Map was a novel concept and innovative tool first introduced by Lamb et al to connect small molecules, genes, and diseases using genomic signatures [Lamb et al (2006), Science 313, 1929-1935]. However, the Connectivity Map had some limitations, particularly there was no effective safeguard against false connections if the observed connections were considered on an individual-by-individual basis. Further when several connections to the same small-molecule compound were viewed as a set, the implicit null hypothesis tested was not the most relevant one for the discovery of real connections. Here we propose a simple and robust method for constructing the reference gene-expression profiles and a new connection scoring scheme, which importantly allows the valuation of statistical significance of all the connections observed. We tested the new method with the two example gene-signatures (HDAC inhibitors and Estrogens) used by Lamb et al and also a new gene signature of immunosuppressive drugs. Our testing with this new method shows that it achieves a higher level of specificity and sensitivity than the original method. For example, our method successfully identified raloxifene and tamoxifen as having significant anti-estrogen effects, while Lamb et al's Connectivity Map failed to identify these. With these properties our new method has potential use in drug development for the recognition of pharmacological and toxicological properties in new drug candidates.Comment: 8 pages, 2 figures, and 2 tables; supplementary data supplied as a ZIP fil

    Long-Term Survival in Octogenarians After Surgical Treatment for Colorectal Cancer:Prevention of Postoperative Complications is Key

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    BackgroundWhether to treat octogenarians with colorectal cancer (CRC) in the same manner as younger patients remains a challenging issue. The purpose of this study was to analyse postoperative complications and long-term survival in a consecutive cohort of octogenarians who were surgically treated for CRC.MethodsOctogenarians with primary CRC suitable for curative surgery between January 2008 and December 2011 were included. Data about comorbidities, tumour stage, and complications were retrospectively collected from patient files. Data about survival were retrieved with use of the Dutch database for persons and addresses. To identify factors associated with severe postoperative complications and postoperative survival, logistic regression analyses, and Cox regression analyses were performed. Odds ratios and hazard ratios (HR) with 95% confidence intervals (CI) were estimated.ResultsIn a series of 108 octogenarians, median age was 83years (range 80-94years). Median follow-up was 47 (range 1-107) months. Major postoperative complications occurred in 25% of the patients. No risk factors for development of severe postoperative complications could be identified. The 30-day mortality was 7%; 1- and 5-year mortality was 19% and 56%, respectively. Overall median survival was 48months: 66months in patients without complications versus 13months in patients with postoperative complications. Postoperative complications were most predictive of decreased survival (HR 3.16; 95% CI 1.79-5.59), even including tumour characteristics, comorbidity, and emergency surgery.ConclusionsLong-term survival in octogenarians deemed fit for surgery is reasonably good. Prevention of major postoperative complications could further improve clinical outcome.</p
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