886 research outputs found

    Wandel der Lehre. Persönlicher Rückblick

    Get PDF

    Pursuing More Aggressive Timelines in the Surgical Treatment of Traumatic Spinal Cord Injury (TSCI): A Retrospective Cohort Study with Subgroup Analysis

    Get PDF
    Background: The optimal timing of surgical therapy for traumatic spinal cord injury (TSCI) remains unclear. The purpose of this study is to evaluate the impact of “ultra-early” (<4 h) versus “early” (4–24 h) time from injury to surgery in terms of the likelihood of neurologic recovery. Methods: The effect of surgery on neurological recovery was investigated by comparing the assessed initial and final values of the American Spinal Injury Association (ASIA) Impairment Scale (AIS). A post hoc analysis was performed to gain insight into different subgroup regeneration behaviors concerning neurological injury levels. Results: Datasets from 69 cases with traumatic spinal cord injury were analyzed. Overall, 19/46 (41.3%) patients of the “ultra-early” cohort saw neurological recovery compared to 5/23 (21.7%) patients from the “early” cohort (p = 0.112). The subgroup analysis revealed differences based on the neurological level of injury (NLI) of a patient. An optimal cutpoint for patients with a cervical lesion was estimated at 234 min. Regarding the prediction of neurological improvement, sensitivity was 90.9% with a specificity of 68.4%, resulting in an AUC (area under the curve) of 84.2%. In thoracically and lumbar injured cases, the estimate was lower, ranging from 284 (thoracic) to 245 min (lumbar) with an AUC of 51.6% and 54.3%. Conclusions: Treatment within 24 h after TSCI is associated with neurological recovery. Our hypothesis that intervention within 4 h is related to an improvement in the neurological outcome was not confirmed in our collective. In a clinical context, this suggests that after TSCI there is a time frame to get the right patient to the right hospital according to advanced trauma life support (ATLS) guidelines

    Is Quantum Chaos Weaker Than Classical Chaos?

    Full text link
    We investigate chaotic behavior in a 2-D Hamiltonian system - oscillators with anharmonic coupling. We compare the classical system with quantum system. Via the quantum action, we construct Poincar\'{e} sections and compute Lyapunov exponents for the quantum system. We find that the quantum system is globally less chaotic than the classical system. We also observe with increasing energy the distribution of Lyapunov exponts approaching a Gaussian with a strong correlation between its mean value and energy.Comment: text (LaTeX) + 7 figs.(ps

    The Pennsylvania Dutchman Vol. 8, No. 4

    Get PDF
    ● Such Fancy Boxes, Yet ● Dried Corn ● Pennsylvania Dutch Cooking is Corny ● The Amish at Play ● Colonial Button Mold ● Illness and Cure of Domestic Animals Among the Pennsylvania Dutch ● Pennsylvania Dutch Pioneershttps://digitalcommons.ursinus.edu/dutchmanmag/1011/thumbnail.jp

    The Pennsylvania Dutchman Vol. 8, No. 3

    Get PDF
    ● The Dutch Touch in Iron ● The Pennsylvania Dutch Village ● Five June Days ● On an Amish Farm ● Traveling Pennsylvanians ● The Trail of the Stone Arched Bridges in Berks County ● Displaced Dutchmen Crave Shoo-flies ● Florence Starr Taylor ● Pennsylvania Dutch Pioneers ● Zinzendorf and Moravian Research ● Sheep in Dutchlandhttps://digitalcommons.ursinus.edu/dutchmanmag/1010/thumbnail.jp

    The Dutchman Vol. 6, No. 2

    Get PDF
    ● Spatterware ● That\u27s a Lot of Boloney ● A Dutch Touch ● Birds in Dutchland ● Cornelius Weygandt Day ● Brick-end Barns ● Hardly Bigger Than a Peanut ● Pennsylvania Dutch Pioneers ● Sycamores in Dutchland ● The Zehn-uhr Schtickhttps://digitalcommons.ursinus.edu/dutchmanmag/1001/thumbnail.jp

    The Dutchman Vol. 6, No. 1

    Get PDF
    ● Editorial ● Somerset County Decorated Barns ● Butter Molds ● Restaurants, too, Go Dutch ● The Hostetter Fractur Collection ● Bindnagle\u27s Church ● The Harry S. High Folk Art Collection ● Lebanon Valley Date Stones ● Of Bells and Bell Towers ● John Durang, the First Native American Dancer ● Stoffel Rilbps\u27 Epistle ● The First Singing of Our National Anthem ● Pennsylvania Dutch Pioneershttps://digitalcommons.ursinus.edu/dutchmanmag/1000/thumbnail.jp

    Approach to ergodicity in quantum wave functions

    Full text link
    According to theorems of Shnirelman and followers, in the semiclassical limit the quantum wavefunctions of classically ergodic systems tend to the microcanonical density on the energy shell. We here develop a semiclassical theory that relates the rate of approach to the decay of certain classical fluctuations. For uniformly hyperbolic systems we find that the variance of the quantum matrix elements is proportional to the variance of the integral of the associated classical operator over trajectory segments of length THT_H, and inversely proportional to TH2T_H^2, where TH=hρˉT_H=h\bar\rho is the Heisenberg time, ρˉ\bar\rho being the mean density of states. Since for these systems the classical variance increases linearly with THT_H, the variance of the matrix elements decays like 1/TH1/T_H. For non-hyperbolic systems, like Hamiltonians with a mixed phase space and the stadium billiard, our results predict a slower decay due to sticking in marginally unstable regions. Numerical computations supporting these conclusions are presented for the bakers map and the hydrogen atom in a magnetic field.Comment: 11 pages postscript and 4 figures in two files, tar-compressed and uuencoded using uufiles, to appear in Phys Rev E. For related papers, see http://www.icbm.uni-oldenburg.de/icbm/kosy/ag.htm
    corecore