5,276 research outputs found

    Adobe Flash as a medium for online experimentation: a test of reaction time measurement capabilities

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    Adobe Flash can be used to run complex psychological experiments over the Web. We examined the reliability of using Flash to measure reaction times (RTs) using a simple binary-choice task implemented both in Flash and in a Linux-based system known to record RTs with millisecond accuracy. Twenty-four participants were tested in the laboratory using both implementations; they also completed the Flash version on computers of their own choice outside the lab. RTs from the trials run on Flash outside the lab were approximately 20 msec slower than those from trials run on Flash in the lab, which in turn were approximately 10 msec slower than RTs from the trials run on the Linux-based system (baseline condition). RT SDs were similar in all conditions, suggesting that although Flash may overestimate RTs slightly, it does not appear to add significant noise to the data recorded

    Health Care Expenditures in OECD Countries: A Panel Unit Root and Cointegration Analysis

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    This paper examines the linkationship between health care expenditures and gdp for 21 oecd countries using panel cointegration techniques. the analysis accounts for the fact that health care expenditures are not solely driven by income, but also by medical progress, where different measures are used. in the extended models, cointegration can be established. the income elasticity is not different from unity, implying that health care is not a luxury good. this finding is robust for alternative proxies of medical progress, and various estimators of the cointegration vector. in addition, cointegration can be detected even between nonstationary common factors.health care expenditures; medical progress, panel cointegration, common factors

    A rotating helical filament in the L1251 dark cloud

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    (Abridged) Aims. We derive the physical properties of a filament discovered in the dark cometary-shaped cloud L1251. Methods. Mapping observations in the NH3(1,1) and (2,2) inversion lines, encompassing 300 positions toward L1251, were performed with the Effelsberg 100-m telescope at a spatial resolution of 40 arcsec and a spectral resolution of 0.045 km/s. Results. The filament L1251A consists of three condensations (alpha, beta, and gamma) of elongated morphology, which are combined in a long and narrow structure covering a 38 arcmin by 3 arcmin angular range. The opposite chirality (dextral and sinistral) of the alpha+beta and gamma condensations indicates magnetic field helicities of two types, negative and positive, which were most probably caused by dynamo mechanisms. We estimated the magnetic Reynolds number Rm > 600 and the Rossby number R < 1, which means that dynamo action is important.Comment: 21 pages, 10 figures, 1 table. Accepted for publication in A&

    THE ROLE OF IMPORTS IN THE CHANGING NATURE OF THE U.S. FARM MACHINERY INDUSTRY

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    Agribusiness, International Relations/Trade,

    The baryon density at z=0.9-1.9 - Tracing the warm-hot intergalactic medium with broad Lyman alpha absorption

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    We present an analysis of the Lyman alpha forests of five quasar spectra in the near UV. Properties of the intergalactic medium (IGM) at an intermediate redshift interval (0.9 < z < 1.9) are studied. The amount of baryons in the diffuse photoionised IGM and the warm-hot intergalactic medium (WHIM) are traced to get constraints on the redshift evolution of the different phases of the intergalactic gas. The baryon density of the diffuse IGM is determined with photoionisation calculations under the assumption of local hydrostatic equilibrium. We assume that the gas is ionised by a metagalactic background radiation with a Haardt & Madau (2001) spectrum. The WHIM is traced with broad Lyman alpha (BLA) absorption. The properties of a number of BLA detections are studied. Under the assumption of collisional ionisation equilibrium a lower limit to the baryon density could be estimated. It is found that the diffuse photoionised IGM contains at least 25% of the total baryonic matter at redshifts 1 < z < 2. For the WHIM a lower limit of 2.4% could be determined. Furthermore the data indicates that the intergalactic gas is in a state of evolution at z=1.5. We confirm that a considerable part of the WHIM is created between z=1 and z=2.Comment: 6 pages, 1 figure, accepted for publication in A&

    Star-forming regions of the Aquila rift cloud complex. II. Turbulence in molecular cores probed by NH3 emission

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    (Abridged) Aims. We intend to derive statistical properties of stochastic gas motion inside the dense low mass star forming molecular cores traced by NH3(1,1) and (2,2) emission lines. Methods. We use the spatial two-point autocorrelation (ACF) and structure functions calculated from maps of the radial velocity fields. Results. We find oscillating ACFs which eventually decay to zero with increasing lags on scales of 0.04 <= l <= 0.5 pc. The current paradigm supposes that the star formation process is controlled by the interplay between gravitation and turbulence, the latter preventing molecular cores from a rapid collapse due to their own gravity. Thus, oscillating ACFs may indicate a damping of the developed turbulent flows surrounding the dense but less turbulent core - a transition to dominating gravitational forces and, hence, to gravitational collapse.Comment: 11 pages, 16 figures, 3 tables, to be published in Astronomy and Astrophysic

    A New Version of Reimers' law of Mass Loss Based on a Physical Approach

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    We present a new semi-empirical relation for the mass loss of cool stellar winds, which so far has frequently been described by "Reimers' law". Originally, this relation was based solely on dimensional scaling arguments without any physical interpretation. In our approach, the wind is assumed to result from the spill-over of the extended chromosphere, possibly associated with the action of waves, especially Alfven waves, which are used as guidance in the derivation of the new formula. We obtain a relation akin to the original Reimers law, but which includes two new factors. They reflect how the chromospheric height depends on gravity and how the mechanical energy flux depends, mainly, on effective temperature. The new relation is tested and sensitively calibrated by modelling the blue end of the Horizontal Branch of globular clusters. The most significant difference from mass loss rates predicted by the Reimers relation is an increase by up to a factor of 3 for luminous late-type (super-)giants, in good agreement with observations.Comment: 12 pages, 4 figures, accepted by ApJ Letter

    Lending a Megaphone to the Muted: The Merits of Comprehensive Conflict Engagement through Photovoice in Refugee Resettlement Communities

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    Local refugee resettlement sites are often overlooked as hotspots of conflict because of the unstated assumption that resettlement and escape from militarized conflict automatically mean peace. However, refugees are resettled in local communities into which old conflicts are imported, and where new ones emerge as refugees and locals need to find ways of coexisting despite cultural differences. This research was developed in response to calls by the US Office of Refugee Resettlement and the US Senate Committee on Foreign Relations for grassroots-level data on the challenges faced by residents of resettlement communities and for the development of strategies for promoting intercultural understanding. This dissertation delineates the development of the Comprehensive Conflict Engagement Model, based on which the image- and dialogue-based Photovoice methodology was modified and applied as a practical conflict intervention. This work bridges the gap between conflict theory and practice by collecting bottom-up information about the dynamics that shape people’s lives in Clarkston, a refugee resettlement hub in Georgia, and exploring the utility of the CCEM applied through Photovoice as a comprehensive conflict engagement strategy that concurrently targets the internal, relational, and structural bases of conflict. The results suggest that the participants were generally satisfied with aspects of their environment on which they had an impact and dissatisfied when they were impacted uni-directionally, without reciprocal relationships and the power to actively shape their experiences. The results further demonstrate that a CCEM-based adaptation of Photovoice is a suitable comprehensive conflict engagement strategy for practitioners operating at the community level
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