1,287 research outputs found

    Constructing Melchior Lorichs's 'Panorama of Constantinople'

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    In Constructing Melchior Lorichs's Panorama of Constantinople, Nigel Westbrook, Kenneth Rainsbury Dark, and Rene Van Meeuwen propose that Melchior Lorichs's 1559 Panorama of Constantinople was created by using a viewing grid. The panorama is thus a reliable graphic source for the lost or since-altered Ottoman and Byzantine buildings of the city. The panorama appears to lie outside the conventional symbolic mode of topographical depiction common for its period and constitutes a rare "scientific" record of an encounter of a perspicacious observer with a vast subject. The drawing combines elements of allegory with extensive empirical observation. Several unknown structures, shown on the drawing, have been located in relation to the present-day topography of Istanbul, as a test-case for further research

    USER STUDIES FOR DIGITAL LIBRARIES EVALUATION AND DEVELOPMENT

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    This tutorial - the only one in JCDL 2012 Conference - introduces a range of methods which can be applied to understand better user needs and expectations (surveys, questionnaires, interviews, deep log analysis, personas, eye tracking, ethnographic studies) and to give a practical feel how they work in real practice through a series of recent studies. It includes real life international case study which will help the participants to get a better understanding what studies could be particularly helpful according to the products and services they develop, how to involve user s in digital library evaluation, and how to engage better with users

    Effective Hamiltonian study of excitations in a boson- fermion mixture with attraction between components

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    An effective Hamiltonian for the Bose subsystem in the mixture of ultracold atomic clouds of bosons and fermions with mutual attractive interaction is used for investigating collective excitation spectrum. The ground state and mode frequencies of the 87^{87}Rb and 40^{40}K mixture are analyzed quantitatively at zero temperature. We find analytically solutions of the hydrodynamics equations in the Thomas- Fermi approximation. We discuss the relation between the onset of collapse and collective modes softening and the dependence of collective oscillations on scattering length and number of boson atoms.Comment: 9 pages, 5 figure

    PREDICTING THE DATE OF FIRST CATCH OF THE CORN EARWORM, HELICOVERPA ZEA, IN CENTRAL U.S.

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    This paper develops predictive (or correlative) models for the date of first catch of the com earworm, Helicoverpa zea, as a basis for identifying biotic and abiotic factors that influence dispersal and migration. Data described in Goodenough et al. (1988, J. Econ. Entomol.) on the catch of H. zea gathered at over 150 sites predominantly in the central U.S. from 1983 to 1986 are analyzed. The dependent variables, Y1 and Y2, are date of first meaningful catch and date when cumulative catch exceeds 5, respectively; the independent variables are latitude, longitude and elevation of the site. Outstanding among the findings are the following : 1) There is no statistical evidence based on all the data that the slopes of the simple linear regression models of Y2 on latitude differ among the four years. The common slope estimate is 8.11 days/degree, the intercepts differ by as many as 16 days, and the combined model has r2 = 0.69. 2) There is no statistical evidence based on the data in the central U.S. that the partial slopes of the multiple regression models of Y2 on latitude and longitude differ among the four years. The common partial slope estimates are 7.36 and -1.27 days/degree, the intercepts differ by as many as 17 days, and the combined model has R 2= 0.69. Second order terms are not significant . 3) An exploratory analysis using GIS mapping software suggests that elevation is also a significant predictor variable. The suggestion is confirmed in multiple regression models for both Y1 and Y22= 0.71 and 0.72 respectively. The intercepts differ by as many as 20 and 17 days, respectively, over the four years . These results imply that the time of fi!\u27st appearance at any location in the central U.S. could be predicted once the date of first appearance in South Texas is ascertained. They also demonstrate the utility of analyzing residuals using GIS mapping software. Research is in progress to investigate other possible predictor variables including soil moisture, soil temperature and precipitation

    X-Atlas: An Online Archive of Chandra's Stellar High Energy Transmission Gratings Observations

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    The high-resolution X-ray spectroscopy made possible by the 1999 deployment of the Chandra X-ray Observatory has revolutionized our understanding of stellar X-ray emission. Many puzzles remain, though, particularly regarding the mechanisms of X-ray emission from OB stars. Although numerous individual stars have been observed in high-resolution, realizing the full scientific potential of these observations will necessitate studying the high-resolution Chandra dataset as a whole. To facilitate the rapid comparison and characterization of stellar spectra, we have compiled a uniformly processed database of all stars observed with the Chandra High Energy Transmission Grating (HETG). This database, known as X-Atlas, is accessible through a web interface with searching, data retrieval, and interactive plotting capabilities. For each target, X-Atlas also features predictions of the low-resolution ACIS spectra convolved from the HETG data for comparison with stellar sources in archival ACIS images. Preliminary analyses of the hardness ratios, quantiles, and spectral fits derived from the predicted ACIS spectra reveal systematic differences between the high-mass and low-mass stars in the atlas and offer evidence for at least two distinct classes of high-mass stars. A high degree of X-ray variability is also seen in both high and low-mass stars, including Capella, long thought to exhibit minimal variability. X-Atlas contains over 130 observations of approximately 25 high-mass stars and 40 low-mass stars and will be updated as additional stellar HETG observations become public. The atlas has recently expanded to non-stellar point sources, and Low Energy Transmission Grating (LETG) observations are currently being added as well

    How much time do nurses have for patients? a longitudinal study quantifying hospital nurses' patterns of task time distribution and interactions with health professionals

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    <p>Abstract</p> <p>Background</p> <p>Time nurses spend with patients is associated with improved patient outcomes, reduced errors, and patient and nurse satisfaction. Few studies have measured how nurses distribute their time across tasks. We aimed to quantify how nurses distribute their time across tasks, with patients, in individual tasks, and engagement with other health care providers; and how work patterns changed over a two year period.</p> <p>Methods</p> <p>Prospective observational study of 57 nurses for 191.3 hours (109.8 hours in 2005/2006 and 81.5 in 2008), on two wards in a teaching hospital in Australia. The validated Work Observation Method by Activity Timing (WOMBAT) method was applied. Proportions of time in 10 categories of work, average time per task, time with patients and others, information tools used, and rates of interruptions and multi-tasking were calculated.</p> <p>Results</p> <p>Nurses spent 37.0%[95%CI: 34.5, 39.3] of their time with patients, which did not change in year 3 [35.7%; 95%CI: 33.3, 38.0]. Direct care, indirect care, medication tasks and professional communication together consumed 76.4% of nurses' time in year 1 and 81.0% in year 3. Time on direct and indirect care increased significantly (respectively 20.4% to 24.8%, P < 0.01;13.0% to 16.1%, P < 0.01). Proportion of time on medication tasks (19.0%) did not change. Time in professional communication declined (24.0% to 19.2%, P < 0.05). Nurses completed an average of 72.3 tasks per hour, with a mean task length of 55 seconds. Interruptions arose at an average rate of two per hour, but medication tasks incurred 27% of all interruptions. In 25% of medication tasks nurses multi-tasked. Between years 1 and 3 nurses spent more time alone, from 27.5%[95%CI 24.5, 30.6] to 39.4%[34.9, 43.9]. Time with health professionals other than nurses was low and did not change.</p> <p>Conclusions</p> <p>Nurses spent around 37% of their time with patients which did not change. Work patterns were increasingly fragmented with rapid changes between tasks of short length. Interruptions were modest but their substantial over-representation among medication tasks raises potential safety concerns. There was no evidence of an increase in team-based, multi-disciplinary care. Over time nurses spent significantly less time talking with colleagues and more time alone.</p

    Not Just Efficiency: Insolvency Law in the EU and Its Political Dimension

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    Certain insolvency law rules, like creditors’ priorities and set-off rights, have a distributive impact on creditors. Distributional rules reflect the hierarchies of values and interests in each jurisdiction and, as a result, have high political relevance and pose an obstacle to reforming the EU Insolvency Regulation. This paper will show the difficulty of reform by addressing two alternative options to regulate cross-border insolvencies in the European Union. The first one is the ‘choice model’, under which companies can select the insolvency law they prefer. Although such a model would allow distressed firms to select the most efficient insolvency law, it would also displace Member States’ power to protect local constituencies. The choice model therefore produces negative externalities and raises legitimacy concerns. The opposite solution is full harmonisation of insolvency law at EU level, including distributional rules. Full harmonisation would have the advantage of internalising all externalities produced by cross-border insolvencies. However, the EU legislative process, which is still based on negotiations between states, is not apt to decide on distributive insolvency rules; additionally, if harmonisation includes such rules, it will indirectly modify national social security strategies and equilibria. This debate shows that the choice regarding power allocation over bankruptcies in the EU depends on the progress of European integration and is mainly a matter of political legitimacy, not only of efficiency

    Trapped-ion probing of light-induced charging effects on dielectrics

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    We use a string of confined 40^{40}Ca+^+ ions to measure perturbations to a trapping potential which are caused by light-induced charging of an anti-reflection coated window and of insulating patches on the ion-trap electrodes. The electric fields induced at the ions' position are characterised as a function of distance to the dielectric, and as a function of the incident optical power and wavelength. The measurement of the ion-string position is sensitive to as few as 4040 elementary charges per Hz\sqrt{\mathrm{Hz}} on the dielectric at distances of order millimetres, and perturbations are observed for illumination with light of wavelengths as long as 729\,nm. This has important implications for the future of miniaturised ion-trap experiments, notably with regards to the choice of electrode material, and the optics that must be integrated in the vicinity of the ion. The method presented can be readily applied to the investigation of charging effects beyond the context of ion trap experiments.Comment: 11 pages, 5 figure
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