2,569 research outputs found
A two-loop relation between inclusive radiative and semileptonic B-decay spectra
A shape-function independent relation is derived between the partial
B->X_u+l+nu decay rate with a cut on P_+=E_X-P_X<Delta and a weighted integral
over the normalized B->X_s+gamma photon-energy spectrum. The leading-power
contribution to the weight function is calculated at next-to-next-to-leading
order in renormalization-group improved perturbation theory, including exact
two-loop matching corrections at the scale mu_i^2 ~ m_b*Lambda_{QCD}. The
overall normalization of the weight function is obtained up to yet unknown
corrections of order [alpha_s(m_b)]^2. Power corrections from phase-space
factors are included exactly, while the remaining subleading contributions are
included at first order in 1/m_b. At this level unavoidable hadronic
uncertainties enter, which are estimated in a conservative way. The combined
theoretical accuracy in the extraction of |V_{ub}| is at the level of 5% if a
value of Delta near the charm threshold can be achieved experimentally.Comment: 22 pages, 4 figures; few comments and one reference added; version to
appear in JHE
Semantische und syntaktische Integration von konkurrierenden Informationssystemen in der Medizin
Die Integration von Informationssystemen zu einem Krankenhaus-Informationssystem wird seit ĂŒber 30 Jahren als eine
der dringendsten Herausforderungen der Medizinischen Informatik angesehen.
Typischerweise entsteht ein KIS durch die Integration von Einzelsystemen zu einem Informationssystem.
Diese Entwicklung lĂ€sst sich auch am UniversitĂ€tsklinikum MĂŒnster verfolgen. Dort wird seit 1995 ein integriertes System fĂŒr die Patientendatenverwaltung eingesetzt. Hinzu kommen zahlreiche Systeme in diagnostischen und administrativen Abteilungen. Gegenstand dieser Arbeit ist die Analyse der Kommunikationsbeziehungen zwischen dem PDV- und dem Klinischen Arbeitsplatzsystem am UKM und die Darstellung der Kopplung der Systeme. Gezeigt wird, dass die Verwendung von Standards wie HL7 und der Einsatz eines Kommunikationsservers fĂŒr die Kopplung der Systeme kein "plug and play" beinhaltet. Es wird deutlich gemacht, dass der Erfolg einer Integration, neben der
physikalischen und syntaktischen Kopplung, von einer umfassenden Analyse der semantischen Integration der Systeme abhÀngig ist
Low-noise 0.8-0.96- and 0.96-1.12-THz superconductor-insulator-superconductor mixers for the Herschel Space Observatory
Heterodyne mixers incorporating Nb SIS junctions and NbTiN-SiO/sub 2/-Al microstrip tuning circuits offer the lowest reported receiver noise temperatures to date in the 0.8-0.96- and 0.96-1.12-THz frequency bands. In particular, improvements in the quality of the NbTiN ground plane of the SIS devices' on-chip microstrip tuning circuits have yielded significant improvements in the sensitivity of the 0.96-1.12-THz mixers relative to previously presented results. Additionally, an optimized RF design incorporating a reduced-height waveguide and suspended stripline RF choke filter offers significantly larger operating bandwidths than were obtained with mixers that incorporated full-height waveguides near 1 THz. Finally, the impact of junction current density and quality on the performance of the 0.8-0.96-THz mixers is discussed and compared with measured mixer sensitivities, as are the relative sensitivities of the 0.8-0.96- and 0.96-1.12-THz mixers
Using a multi-level tailored design process to develop a customer satisfaction survey for university evaluation
A multi-level procedure is described in order to develop a total quality management survey tool in the field of engineering academia. As a first step a review of
available evaluation tools for universities is conducted, resulting in over 150 items used for evaluation purposes. Secondly all dimensions of educational evaluation used in previous research are summarized, resulting in 15 dimensions. In a third step, items are assigned to the dimensions, overlapping items were combined or removed, and item content and dimensions were adjusted to the specific conditions of the target faculty. Fourthly, the resulting twelve dimensions were used in first, investigative interviews in the target population. Results indicate that eleven dimensions sufficiently mapped all aspects of evaluation. After revising the items to improve understanding in a fifth step cognitive pretests were conducted. The final revision resulted in 83 items assigned to eleven dimensions
Empirical competence-testing: A psychometric examination of the German version of the Emotional Competence Inventory
The âEmotional Competence Inventoryâ (ECI 2.0) by Goleman and Boyatzis assesses emotional intelligence (EI) in organizational context by means of 72 items in 4 clusters (self-awareness, self- management, social awareness, social skills) which at large consist of 18 competencies. Our study examines the psychometric properties of the first German translation of this instrument in two different surveys (N = 236). If all items are included in reliability analysis the ECI is reliable (Cronbachâs Alpha = .90), whereas the reliability of the four sub dimensions is much smaller (Alpha = .62 - .81). For 43 items the corrected item-total correlation with its own scale is higher than correlations with the other three clusters. Convergent validity was examined by using another EI instrument (Wong & Law, 2002). We found a significant correlation between the two instruments (r = .41). The German version of the ECI seems to be quite useful, although the high reliability is achieved by a large number of items. Possibilities of improvement are discussed
Evidence for impaired extinction learning in humans after distal stress exposure
Stressful or traumatic events can be risk factors for anxiety or trauma- and stressor-related disorders. In this regard, it has been shown that stress affects aversive learning and memory processes. In rodents, stress exposure 10 days prior to fear acquisition impairs fear extinction. However, in humans the effect of distal stress on fear conditioning is sparse. Therefore, we examined the influence of distal stress on fear memory in humans in two studies. In Study 1, participants underwent either socially evaluated cold-pressor test (SECPT) or sham procedure 10 days or 40 min before a fear conditioning paradigm (four groups, N = 78). In Study 2, context effects were examined by conducting SECPT and sham procedures 10 days prior conditioning either in the later fear conditioning context or in another context (three groups, N = 69). During acquisition phase, one geometrical shape (conditioned stimulus, CS+) was paired with painful electric shocks (unconditioned stimulus, US), but never a second shape (CSâ). Extinction phase was identical to acquisition, but without US delivery. Importantly, for Study 1 these phases were conducted on one day, while for Study 2 on two separated days. Successful fear acquisition was indicated by aversive ratings and startle potentiation to CS+ versus CSâ in both studies. Interestingly, participants stressed 10 days earlier showed impaired extinction on the implicit level (startle potentiation to CS+ vs. CSâ) in Study 1 and only in the acquisition context on the explicit level (aversive ratings for CS+ vs. CSâ) in Study 2. In sum, distal stress may strengthen later acquired fear memories and thereby impair fear extinction. This finding could have clinical implications, showing that prior stress exposure sensitizes later aversive processing and impairs therapy
Emotional Intelligence and its consequences for occupational and life satisfaction - Emotional Intelligence in the context of irrational beliefs
According to Albert Ellis' theory of Rational Emotive Behavior Therapy irrational beliefs (IB) lead to maladaptive emotions. A central component of irrationality is the denial of one's own possibilities to control important aspects of life. A specific IB is that one cannot control and thus cannot avoid certain emotion states. Emotion research considers regulative emotion control a pivotal component of the concept of emotional intelligence (EI). A negative association between IB and EI can thus be theoretically derived from both concepts. Furthermore both should be related to life satisfaction. We examined the relationship between IB and EI using standardized questionnaire instruments and the predictive value of both concepts regarding life satisfaction. We found a significant negative correlation between both conceptions (r = -.21). Life satisfaction and occupational satisfaction are better predicted by IB. RÂČ increases from .04 to .12 when both concepts are incorporated in regression analysis
Experimental investigation of ultracold atom-molecule collisions
Ultracold collisions between Cs atoms and Cs2 dimers in the electronic ground
state are observed in an optically trapped gas of atoms and molecules. The Cs2
molecules are formed in the triplet ground state by cw-photoassociation through
the outer well of the 0g-(P3/2) excited electronic state. Inelastic
atom-molecule collisions converting internal excitation into kinetic energy
lead to a loss of Cs2 molecules from the dipole trap. Rate coefficients are
determined for collisions involving Cs atoms in either the F=3 or F=4 hyperfine
ground state and Cs2 molecules in either highly vibrationally excited states
(v'=32-47) or in low vibrational states (v'=4-6) of the a ^3 Sigma_u^+ triplet
ground state. The rate coefficients beta ~10^{-10} cm^3/s are found to be
largely independent of the vibrational and rotational excitation indicating
unitary limited cross sections.Comment: 4 pages, 3 figures, submitted for publicatio
Comparison of structure and transport properties of concentrated hard and soft sphere fluids
Using Newtonian and Brownian dynamics simulations, the structural and
transport properties of hard and soft spheres have been studied. The soft
spheres were modeled using inverse power potentials (, with
the potential softness). Although the pressure, diffusion coefficient and
viscosity depend at constant density on the particle softness up to extremely
high values of , we show that scaling the density with the freezing point
for every system effectively collapses these parameters for
(including hard spheres), for large densities. At the freezing points, the long
range structure of all systems is identical, when the distance is measured in
units of the interparticle distance, but differences appear at short distances
(due to the different shape of the interaction potential). This translates into
differences at short times in the velocity and stress autocorrelation
functions, although they concur to give the same value of the corresponding
transport coefficient (for the same density to freezing ratio); the microscopic
dynamics also affects the short time behaviour of the correlation functions and
absolute values of the transport coefficients, but the same scaling with the
freezing density works for Newtonian or Brownian dynamics. For hard spheres,
the short time behaviour of the stress autocorrelation function has been
studied in detail, confirming quantitatively the theoretical forms derived for
it.Comment: 8 pages, 10 figure
Experimentelle ĂberprĂŒfung einer evolutionstheoretischen ErklĂ€rung von SchlafplatzprĂ€ferenzen des Menschen
Obwohl Menschen einen groĂen Teil des Tages an ihrem
Schlafplatz verbringen, gibt es kaum experimentelle und
theoriegeleitete Studien zur Schlafplatzwahl des Menschen.
Da der Mensch im Schlaf relativ schutzlos gegenĂŒber Angreifern ist und eine passende Wahl der Schlafumgebung Schutz und damit höhere Ăberlebenschancen bietet, wird die Schlafplatzwahl aus evolutionĂ€rer Perspektive untersucht.
Es wird ein Evolutionsbedingter Psychologischer Mechanismus (EPM) zur Schlafplatzwahl postuliert und daraus abgeleitete Hypothesen ĂŒberprĂŒft: Ein Schlafplatz sollte so gewĂ€hlt werden, dass er schnelle Reaktionen auf Angreifer ermöglicht. Daher sollte (1) vom Bett aus die TĂŒr im Blickfeld sein, (2) das Bett in deutlicher Weise von der TĂŒr abgerĂŒckt sein und (3) bevorzugt in die ZimmerhĂ€lfte gestellt werden, in die sich die TĂŒr öffnet. Eine Studie mit 138 Probanden, die Möbel auf experimentell manipulierten Grundrissen anrichten, kann diese Hypothesen bestĂ€tigen
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