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Search Results: 1 - 10 of 402226 matches for " Clemens M Ortner "
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Evaluation of performance of two different chest tubes with either a sharp or a blunt tip for thoracostomy in 100 human cadavers
Clemens M Ortner, Kurt Ruetzler, Nikolaus Schaumann, Veit Lorenz, Peter Schellongowski, Ernst Schuster, Ramez M Salem, Michael Frass
Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine , 2012, DOI: 10.1186/1757-7241-20-10
Abstract: Twenty emergency physicians performed five tube thoracostomies using both blunt and sharp tipped tube kits in 100 fresh human cadavers (100 thoracostomies with each kit). Time until tube insertion served as primary outcome. Complications and success rate were examined by pathological dissection and served as further outcomes parameters.Difference in mean time until tube insertion (63s vs. 59s) was statistically not significant. In both groups, time for insertion decreased from the 1st to the 5th attempt and showed dependency on the cadaver's BMI and on the individual physician. Success rate differed between both groups (92% using blunt vs. 86% using sharp tipped kits) and injuries and misplacements occurred significantly more frequently using chest tubes with sharp tips (p = 0.04).Data suggest that chest drain insertion with trocars is associated with a 6-14% operator-related complication rate. No difference in average time could be found. However, misplacements and organ injuries occurred more frequently using sharp tips. Consequently, if using a trocar technique, the use of blunt tipped kits is recommended.Pneumothorax occurs in 5-41% of all thoracic injuries [1-3], and in up to 25% of patients suffering multiple injuries [4,5]. Besides hemothorax, pneumothorax is the most frequent indication for insertion of a chest tube in trauma patients [4,5]. Complications like tube malposition have been reported in up to 25% of attempted insertions of a chest tube [1,6-8]. In an emergency setting, needle decompression is a widely used technique to manage a tension pneumothorax. However, this is an inexact and potentially dangerous technique. It may be ineffective, and requires subsequent chest tube insertion in a significant number of cases [9-13]. Therefore, needle decompression may be considered primarily as a diagnostic manoeuvre. In advanced pre-hospital emergency care, tube thoracostomy serves as the gold standard in treating tension pneumothorax [14]. The success rate
Teachers’ burnout is related to lowered speed and lowered quality for demanding short-term tasks
Tuulia M. Ortner
Psychological Test and Assessment Modeling , 2012,
Abstract: The present study addressed the relation between self-reported burnout experiences and objective performance in teachers. As an alternative to the distal long-term criteria that are usually used, we followed a new approach using tasks to assess samples of short-term behavior in simulated stressful situations. Tasks requiring low cognitive demand had to be solved in situations involving (a) task collision, (b) a hindrance of the scheduled course of action, or (c) awkward working conditions. Performance data and self-reported work-related experiences were obtained from 103 school teachers. Scales related to self-reported exhaustion revealed several significant medium correlations with objective performance speed as well as performance quality (between r = .23 and r = .30). Lower speed when hindered in their scheduled course of action and a lower quality of task effort under awkward working conditions were shown for teachers suffering from burnout.
Correlation energy of an electron gas in strong magnetic fields at high densities
M. Steinberg,J. Ortner
Physics , 1998, DOI: 10.1103/PhysRevB.58.15460
Abstract: The high-density electron gas in a strong magnetic field B and at zero temperature is investigated. The quantum strong-field limit is considered in which only the lowest Landau level is occupied. It is shown that the perturbation series of the ground-state energy can be represented in analogy to the Gell-Mann Brueckner expression of the ground-state energy of the field-free electron gas. The role of the expansion parameter is taken by r_B= (2/3 \pi^2) (B/m^2) (\hbar r_s /e)^3 instead of the field-free Gell-Mann Brueckner parameter r_s. The perturbation series is given exactly up to o(r_B) for the case of a small filling factor for the lowest Landau level.
Ground-state energy of a high-density electron gas in a strong magnetic field
M. Steinberg,J. Ortner
Physics , 1999,
Abstract: The high-density electron gas in a strong magnetic field B and at zero temperature is investigated. The quantum strong-field limit is considered in which only the lowest Landau level is occupied. It is shown that the perturbation series of the ground-state energy can be represented in analogy to the Gell-Mann Brueckner expression of the ground-state energy of the field-free electron gas. The role of the expansion parameter is taken by $r_B= (2/3 \pi^2) (B/m^2) (\hbar r_S/e)^3$ instead of the field-free Gell-Mann Brueckner parameter r_s.
The use of relativistic action in strong-field nonlinear photoionization
J. Ortner,V. M. Rylyuk
Physics , 1999,
Abstract: Nonlinear relativistic ionization phenomena induced by a strong linearly polarized laser field are considered. The starting point is the classical relativistic action for a free electron moving in the electromagnetic field created by a strong laser beam. This action has been used to calculate semiclassical transition rates. Simple analytical expressions for the ionization rate, the photoelectron emission velocity and for the drift momentum distribution of the photoelectron have been found. The analytical formulas apply to nonrelativistic bound systems as well as to initial states with an energy corresponding to the upper boundary of the lower continuum and to the tunnel as well as the multiphoton regime. In the case of a nonrelativistic bound system we recover the Keldysh formula for the ionization rate. Relativistic effects in the initial state lead to a weak enhancement of the rate of sub-barrier ionization and to the appearance of a nonzero photoelectron leaving velocity.
Relativistic semiclassical approach in strong-field nonlinear photoionization
J. Ortner,V. M. Rylyuk
Physics , 1999, DOI: 10.1103/PhysRevA.61.033403
Abstract: Nonlinear relativistic ionization phenomena induced by a strong laser radiation with elliptically polarization are considered. The starting point is the classical relativistic action for a free electron moving in the electromagnetic field created by a strong laser beam. The application of the relativistic action to the classical barrier-suppression ionization is briefly discussed. Further the relativistic version of the Landau-Dykhne formula is employed to consider the semiclassical sub-barrier ionization. Simple analytical expressions have been found for: (i) the rates of the strong-field nonlinear ionization including relativistic initial and final state effects; (ii) the most probable value of the components of the photoelectron final state momentum; (iii) the most probable direction of photoelectron emission and (iv) the distribution of the photoelectron momentum near its maximum value.
A Real-Time Implementable NMPC Output Feedback for a Diesel Engine Air Path Commande prédictive non linéaire avec retour de sortie implémentable en temps-réel pour un circuit d’air d’un moteur Diesel
Murilo A.,Alamir M.,Ortner P.
Oil & Gas Science and Technology , 2011, DOI: 10.2516/ogst/2011120
Abstract: In this paper, an experimental validation of a parameterized Nonlinear Model Predictive Control (NMPC) scheme with a Moving Horizon Observer (MHO) is presented for a Diesel engine air path. The control design based on the parameterized approach leads to a low dimensional optimization problem which makes the proposed controller real-time implementable. An attractive feature of this control strategy lies in its compatibility with more elaborated and fully nonlinear models since it uses the model as a black box predictor. Dans cet article, une validation expérimentale d’un schéma de commande prédictive non linéaire (CPNL) paramétrique avec un observateur à horizon glissant a été proposé pour le circuit d’air d’un moteur Diesel. La stratégie de commande basée sur l’approche paramétrique à faible dimension s’est montrée implémentable en temps réel et peut être utilisée aussi en tant qu’une solution du type bo te noire indépendamment de la structure du modèle non linéaire.
Ern hrungsphysiologische Analyse des E verhaltens der sterreicherInnen
Kiefer I,Kunze M,Ortner C
Journal für Ern?hrungsmedizin , 2000,
Abstract: Auf Grundlage zweier repr sentativer Bev lkerungsumfragen des Meinungsforschungsinstitutes A. C. Nielsen und des sterreichischen Gallup Institutes erfolgt eine ern hrungsphysiologische Analyse des E verhaltens der sterreicherInnen. Es werden der Energie-, Fett-, Eiwei -, Kohlenhydrat-, Ballaststoff-, Cholesterin- und Saccharosegehalt der typischen Lieblingsspeisen der sterreicherInnen ermittelt und das Naschverhalten sowie die Einsch tzung der sterreichischen Bev lkerung in bezug auf Gesundheit dargestellt. Die Ergebnisse zeigen, da die sterreicherInnen sehr gerne fett- und zuckerhaltige Speisen essen und somit Geschmack deutlich wichtiger ist als Gesundheit. Es wird angeregt, künftig Lebensmittel, Speisen und Getr nke nicht mehr isoliert, sondern im Kontext der Gesamtnahrungsaufnahme zu analysieren.
Effects of Regulating Positive Emotions through Reappraisal and Suppression on Verbal and Non-Verbal Recognition Memory
Catherine N. M. Ortner, Monica de Koning
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062750
Abstract: Previous research has suggested that regulating emotions through reappraisal does not incur cognitive costs. However, in those experiments, cognitive costs were often assessed by recognition memory for information that was contextually related to the emotionally evocative stimuli and may have been incorporated into the reappraisal script, facilitating memory. Furthermore, there is little research on the cognitive correlates of regulating positive emotions. In the current experiment, we tested memory for information that was contextually unrelated to the emotional stimuli and could not easily be related to the reappraisal. Participants viewed neutral and mildly positive slides and either reappraised, suppressed their emotions, or viewed the images with no emotion regulation instruction. At the same time, they heard abstract words that were unrelated to the picture stimuli. Subsequent verbal recognition memory was lower after reappraising than viewing, whereas non-verbal recognition memory (of the slides) was higher after reappraising, but only for positive pictures and when participants viewed the positive pictures first. Suppression had no significant effect on either verbal or non-verbal recognition scores, although there was a trend towards poorer recognition of verbal information. The findings support the notion that reappraisal is effortful and draws on limited cognitive resources, causing decrements in performance in a concurrent memory task.
Equation of state of a strongly magnetized hydrogen plasma
M. Steinberg,J. Ortner,W. Ebeling
Physics , 1998, DOI: 10.1103/PhysRevE.58.3806
Abstract: The influence of a constant uniform magnetic field on the thermodynamic properties of a partially ionized hydrogen plasma is studied. Using the method of Green' s function various interaction contributions to the thermodynamic functions are calculated. The equation of state of a quantum magnetized plasma is presented within the framework of a low density expansion up to the order e^4 n^2 and, additionally, including ladder type contributions via the bound states in the case of strong magnetic fields (2.35*10^{5} T << B << 2.35*10^{9} T). We show that for high densities (n=10^{27-30} m^{-3}) and temperatures T=10^5 - 10^6 K typical for the surface of neutron stars nonideality effects as, e.g., Debye screening must be taken into account.
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