1,687 research outputs found

    A study of the deep structure of the energy landscape of glassy polystyrene: the exponential distribution of the energy-barriers revealed by high-field Electron Spin Resonance spectroscopy

    Full text link
    The reorientation of one small paramagnetic molecule (spin probe) in glassy polystyrene (PS) is studied by high-field Electron Spin Resonance spectroscopy at two different Larmor frequencies (190 and 285 GHz). The exponential distribution of the energy-barriers for the rotational motion of the spin probe is unambigously evidenced at both 240K and 270K. The same shape for the distribution of the energy-barriers of PS was evidenced by the master curves provided by previous mechanical and light scattering studies. The breadth of the energy-barriers distribution of the spin probe is in the range of the estimates of the breadth of the PS energy-barriers distribution. The evidence that the deep structure of the energy landscape of PS exhibits the exponential shape of the energy-barriers distribution agrees with results from extreme-value statistics and the trap model by Bouchaud and coworkers.Comment: Final version in press as Letter to the Editor on J.Phys.:Condensed Matter. Changes in bol

    The Advanced LIGO Photon Calibrators

    Get PDF
    The two interferometers of the Laser Interferometry Gravitaional-wave Observatory (LIGO) recently detected gravitational waves from the mergers of binary black hole systems. Accurate calibration of the output of these detectors was crucial for the observation of these events, and the extraction of parameters of the sources. The principal tools used to calibrate the responses of the second-generation (Advanced) LIGO detectors to gravitational waves are systems based on radiation pressure and referred to as Photon Calibrators. These systems, which were completely redesigned for Advanced LIGO, include several significant upgrades that enable them to meet the calibration requirements of second-generation gravitational wave detectors in the new era of gravitational-wave astronomy. We report on the design, implementation, and operation of these Advanced LIGO Photon Calibrators that are currently providing fiducial displacements on the order of 10−1810^{-18} m/Hz\sqrt{\textrm{Hz}} with accuracy and precision of better than 1 %.Comment: 14 pages, 19 figure

    What makes you not a Buddhist? : a preliminary mapping of values

    Get PDF
    This study sets out to establish which Buddhist values contrasted with or were shared by adolescents from a non-Buddhist population. A survey of attitude toward a variety of Buddhist values was fielded in a sample of 352 non-Buddhist schoolchildren aged between 13 and 15 in London. Buddhist values where attitudes were least positive concerned the worth of being a monk/nun or meditating, offering candles & incense on the Buddhist shrine, friendship on Sangha Day, avoiding drinking alcohol, seeing the world as empty or impermanent and Nirvana as the ultimate peace. Buddhist values most closely shared by non-Buddhists concerned the Law of Karma, calming the mind, respecting those deserving of respect, subjectivity of happiness, welfare work, looking after parents in old age and compassion to cuddly animals. Further significant differences of attitude toward Buddhism were found in partial correlations with the independent variables of sex, age and religious affiliation. Correlation patterns paralleled those previously described in theistic religions. Findings are applied to spiritual, moral, social and cultural development and for the teaching of religious to pupils of no faith adherence. The study recommends that quantitative psychometrics employed to conceptualize Buddhist values by discriminant validity in this study could be extended usefully to other aspects of the study of Buddhism, particularly in quest of validity in the conceptualization of Buddhist identity within specifically Buddhist populations

    Same, Similar, or Something Completely Different? Calibrating Student Surveys and Classroom Observations of Teaching Quality Onto a Common Metric

    Get PDF
    Using item response theory, this study explores whether student survey and classroom observation items can be calibrated onto a common metric of teaching quality. The data comprises 269 lessons of 141 teachers that were scored on the International Comparative Analysis of Learning and Teaching (ICALT) observation instrument and the My Teacher student survey. Using Rasch model concurrent calibration, items from both instruments were calibrated onto a common one‐dimensional metric of teaching quality. Most items were found to fit the model. Challenges pertain mainly to items measuring teaching students learning strategies and differentiation. Explanations for these difficulties are discussed

    Termination of pregnancy due to Thalassemia major, Hemophilia, and Down's Syndrome: the views of Iranian physicians

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Genetic disorders due to <b>kindred </b>marriages are common medical conditions in Iran; however, the legal aspects of abortion remain controversial. This study was undertaken to determine physicians' opinions regarding the termination of pregnancy for three genetic diseases: thalassemia major, hemophilia, and Down's syndrome.</p> <p>Methods</p> <p>A questionnaire was administered to selected physicians by stratified random sampling to determine the following: age, gender, knowledge about prenatal diagnosis of diseases in high risk pregnancies, agreement with abortion, recommended gestational age for abortion, and, if opposed to abortion, the reason.</p> <p>Results</p> <p>Of 323 physicians, who participated in the study, 91.3(295), 40.6(131), and 78.6%(254) were in agreement and 8.7(28), 59.4(192), and 21.4%(69) were opposed to abortion for thalassemia major, hemophilia, and Down's syndrome, respectively. Among 289 physicians opposed to abortion in respect of each of all three conditions, the following reasons were cited: religion, 18; emotional, 10; quality of care, 23; hope to find a new treatment option in the future, 103; miscellaneous reasons, 6; and a combination of these reasons, 129. Among 680 physicians in agreement with abortion in relation to all of the diseases, 4.6%(31) were agreed with abortion in less than 12 weeks gestation, 79.2%(538) in less than 16 weeks gestation, 5.6%(38) in less than 20 weeks gestation, 2.2%(15) in less than 24 weeks gestation, and 8.4%(58) were agreed with beyond the 24 weeks of gestational age.</p> <p>Conclusion</p> <p>The majority of physicians were in agreement with abortion for thalassemia major and Down's syndrome because of the overall prognosis, but opposed to abortion for hemophilia.</p

    Cardiac iron concentration in relation to systemic iron status and disease severity in non-ischaemic heart failure with reduced ejection fraction

    Get PDF
    Aims: Low cardiac iron levels promote heart failure in experimental models. While cardiac iron concentration (CI) is decreased in patients with advanced heart failure with reduced ejection fraction (HFrEF), CI has never been measured in non-advanced HFrEF. We measured CI in left ventricular (LV) endomyocardial biopsies (EMB) from patients with non-advanced HFrEF and explored CI association with systemic iron status and disease severity. Methods and results: We enrolled 80 consecutive patients with non-ischaemic HFrEF with New York Heart Association class II or III symptoms and a median (interquartile range) LV ejection fraction of 25 (18–33)%. CI was 304 (262–373) ÎŒg/g dry tissue. CI was not related to immunohistological findings or the presence of cardiotropic viral genomes in EMBs and was not related to biomarkers of systemic iron status or anaemia. Patients with CI in the lowest quartile (CIQ1) had lower body mass indices and more often presented with heart failure histories longer than 6 months than patients in the upper three quartiles (CIQ2–4). CIQ1 patients had higher serum N-terminal pro-B-type natriuretic peptide levels than CIQ2–4 patients [3566 (1513–6412) vs. 1542 (526–2811) ng/L; P = 0.005]. CIQ1 patients also had greater LV end-diastolic (P = 0.001) and end-systolic diameter indices (P = 0.003) and higher LV end-diastolic pressures (P = 0.046) than CIQ2–4 patients. Conclusion: Low CI is associated with greater disease severity in patients with non-advanced non-ischaemic HFrEF. CI is unrelated to systemic iron homeostasis. The prognostic and therapeutic implications of CI measurements in EMBs should be further explored

    A Standardised Procedure for Evaluating Creative Systems: Computational Creativity Evaluation Based on What it is to be Creative

    Get PDF
    Computational creativity is a flourishing research area, with a variety of creative systems being produced and developed. Creativity evaluation has not kept pace with system development with an evident lack of systematic evaluation of the creativity of these systems in the literature. This is partially due to difficulties in defining what it means for a computer to be creative; indeed, there is no consensus on this for human creativity, let alone its computational equivalent. This paper proposes a Standardised Procedure for Evaluating Creative Systems (SPECS). SPECS is a three-step process: stating what it means for a particular computational system to be creative, deriving and performing tests based on these statements. To assist this process, the paper offers a collection of key components of creativity, identified empirically from discussions of human and computational creativity. Using this approach, the SPECS methodology is demonstrated through a comparative case study evaluating computational creativity systems that improvise music

    A First Search for coincident Gravitational Waves and High Energy Neutrinos using LIGO, Virgo and ANTARES data from 2007

    Get PDF
    We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place limits on the density of joint high energy neutrino - gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events.Comment: 19 pages, 8 figures, science summary page at http://www.ligo.org/science/Publication-S5LV_ANTARES/index.php. Public access area to figures, tables at https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p120000
    • 

    corecore