859 research outputs found

    Surrogate models for direct dark matter detection

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    In this work we introduce RAPIDD, a surrogate model that speeds up the computation of the expected spectrum of dark matter particles in direct detection experiments. RAPIDD replaces the exact calculation of the dark matter differential rate (which in general involves up to three nested integrals) with a much faster parametrization in terms of ordinary polynomials of the dark matter mass and couplings, obtained in an initial training phase. In this article, we validate our surrogate model on the multi-dimensional parameter space resulting from the effective field theory description of dark matter interactions with nuclei, including also astrophysical uncertainties in the description of the dark matter halo. As a concrete example, we use this tool to study the complementarity of different targets to discriminate simplified dark matter models. We demonstrate that RAPIDD is fast and accurate, and particularly well-suited to explore a multi-dimensional parameter space, such as the one in effective field theory approach, and scans with a large number of evaluations

    Radiotherapy optimAl Design: An Academic Radiotherapy Treatment Design System

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    Optimally designing radiotherapy and radiosurgery treatments to increase the likelihood of a successful recovery from cancer is an important application of operations research. Researchers have been hindered by the lack of academic software that supports head-to-head comparisons of different techniques, and this article addresses the inherent difficulties of designing and implementing an academic treatment planning system. In particular, this article details the algorithms and the software design of Radiotherapy optimAl Design (RAD)

    Ten-year audit of Lichtenstein hernioplasty under local anaesthesia performed by surgical residents

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    <p>Abstract</p> <p>Background</p> <p>To analyse in a prospective trial the long-term results of Lichtenstein hernioplasty performed by surgical trainees.</p> <p>Methods</p> <p>Training of tension-free Lichtenstein hernia operation was started in our ambulatory unit as an outpatient procedure under local anaesthesia in 1996. After performing 36 teaching operations together with residents and their supervising specialist, 281 patients were operated during 1996-2000 either by one senior consultant (n = 141) or by 12 surgical trainees (n = 140). After 10 years, 247 (88%) patients were available for the long-term assessment.</p> <p>Results</p> <p>After one month postoperatively, the rate of wound infections (consultant 1.1%, residents 0.7%) and hematomas (consultant 1.1%, residents 3.0%) were low and not related to surgeon's training level (ns). Only 6 (2.1%) clinically evident recurrences were found after 10 years: two after specialist repair and four after trainee repair (ns). Although one third of the patients reported some discomfort after 3 and 10 years, 93-95% of the patients were very satisfied with the operation, with no statistical difference between the surgeons.</p> <p>Conclusion</p> <p>Ambulatory open mesh repair under local anaesthesia was a safe operation and the long-term results were acceptable among the patients operated by surgical trainees.</p

    Impact Factor: outdated artefact or stepping-stone to journal certification?

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    A review of Garfield's journal impact factor and its specific implementation as the Thomson Reuters Impact Factor reveals several weaknesses in this commonly-used indicator of journal standing. Key limitations include the mismatch between citing and cited documents, the deceptive display of three decimals that belies the real precision, and the absence of confidence intervals. These are minor issues that are easily amended and should be corrected, but more substantive improvements are needed. There are indications that the scientific community seeks and needs better certification of journal procedures to improve the quality of published science. Comprehensive certification of editorial and review procedures could help ensure adequate procedures to detect duplicate and fraudulent submissions.Comment: 25 pages, 12 figures, 6 table

    <i>Gaia</i> Data Release 1. Summary of the astrometric, photometric, and survey properties

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    Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7. Aims. A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release. Methods. The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue. Results. Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the HIPPARCOS and Tycho-2 catalogues – a realisation of the Tycho-Gaia Astrometric Solution (TGAS) – and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of ∼3000 Cepheid and RR-Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr−1 for the proper motions. A systematic component of ∼0.3 mas should be added to the parallax uncertainties. For the subset of ∼94 000 HIPPARCOS stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr−1. For the secondary astrometric data set, the typical uncertainty of the positions is ∼10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to ∼0.03 mag over the magnitude range 5 to 20.7. Conclusions. Gaia DR1 is an important milestone ahead of the next Gaia data release, which will feature five-parameter astrometry for all sources. Extensive validation shows that Gaia DR1 represents a major advance in the mapping of the heavens and the availability of basic stellar data that underpin observational astrophysics. Nevertheless, the very preliminary nature of this first Gaia data release does lead to a number of important limitations to the data quality which should be carefully considered before drawing conclusions from the data

    Associations between music education, intelligence, and spelling ability in elementary school

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    Musical education has a beneficial effect on higher cognitive functions, but questions arise whether associations between music lessons and cognitive abilities are specific to a domain or general. We tested 194 boys in Grade 3 by measuring reading and spelling performance, non verbal intelligence and asked parents about musical activities since preschool. Questionnaire data showed that 53% of the boys had learned to play a musical instrument. Intelligence was higher for boys playing an instrument (p < .001). To control for unspecific effects we excluded families without instruments. The effect on intelligence remained (p < .05). Furthermore, boys playing an instrument showed better performance in spelling compared to the boys who were not playing, despite family members with instruments (p < .01). This effect was observed independently of IQ. Our findings suggest an association between music education and general cognitive ability as well as a specific language link

    Deconstructing Disability: A Philosophy for Inclusion

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    This article offers derrida's deconstruction as a philosophy and practical strategy that challenges the assumed, factual nature of "disability" as a construct explaining human differences. The appeal of deconstruction lies in the contradictory philosophy currently articulated by the inclusion movement, a philosophy that simultaneously supports the disability construct as objective reality while calling for students "with disabilities" to be placed in educational settings designed for students considered nondisabled. This article proposes deconstruction as one coherent philosophical orientation for inclusion, an approach that critiques the political and moral hierarchy of ability and disability. A deconstructionist critique of disability is explained and demonstrated. Practical suggestions for the utilization of deconstruction by special educators are outlined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68721/2/10.1177_074193259701800605.pd

    'A critical autoethnography of a doctoral students ’ research journey: learning to take risks in the academy

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    What is missing in present-day physical education teacher education research is the individual female doctoral student perspective and how individuals come to understand academic research culture within the neoliberal university. Through a critical autoethnography, this paper uncovered a transformative learning journey of one doctoral student as she encountered the field of research in higher education. After taking a critically orientated qualitative methods class, the doctoral student recognised that the neoliberal university includes a research agenda entwined in politics, finding that neophyte researchers should be aware of the ‘mess’ (Cheek, J. (2017). Qualitative inquiry, research marketplaces, and neoliberalism. In N. K. Denzin, & M. D. Giardina (Eds.), Qualitative Inquiry in Neoliberal Times (pp. 19–36). New York: Routledge). By questioning how one is disciplined in research and through becoming aware of normalising techniques, the doctoral student interrogated her research methods and philosophical orientation. Ethnodrama (Denzin, N. K. (2010). The qualitative manifesto. Walnut Creek: Left Coast Press) and autoethnography provided the doctoral student with an opportunity for alternate meaning-making, which can be productive in understanding the journey of becoming in academia
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