917 research outputs found
On Fermionic Shadow Wave Functions for strongly-correlated multi-reference systems based on a single Slater determinant
We demonstrate that extending the Shadow Wave Function to fermionic systems
facilitates to accurately calculate strongly-correlated multi-reference systems
such as the stretched H2 molecule. This development considerably extends the
scope of electronic structure calculations and enables to efficiently recover
the static correlation energy using just a single Slater determinant.Comment: 6 pages, 2 figure
Idiopathische thrombozytopenische Purpura im Kindesalter
Zusammenfassung: Die idiopathische thrombozytopenische Purpura (ITP) ist eine Blutungskrankheit, die durch eine verkürzte Lebensdauer der Thrombozyten charakterisiert ist. Sie ist heterogen ausgeprägt und wird durch endogene und erworbene Faktoren beeinflusst. Sie ist eine Ausschlussdiagnose, deren Differenzialdiagnose stets bedacht werden muss. Die Unkenntnis der Ätiologie und der Mangel an klinischen Daten aus kontrollierten prospektiven Studien haben Kontroversen hinsichtlich Diagnose und Behandlung zur Folge. Die bisherigen prospektiven Therapiestudien haben die Beschleunigung des Thrombozytenanstiegs zum Ziel. Diese Zielsetzung wird oft in den klinischen Alltag übertragen, ohne dass bisher gezeigt werden konnte, dass ein rascher Thrombozytenanstieg von klinischem Wert ist. Bei der Behandlung des Patienten mit ITP ist meist eine Vorbeugung vor fatalen Blutungen beabsichtigt. Diese sind aber im Kindesalter sehr selten. Die Therapieziele im klinischen Alltag, aber auch in klinischen Studien müssen überdacht werden. Andere wichtige Gesichtspunkte sind Blutungen, die Lebensqualität des Patienten und seiner Angehörigen, Nebenwirkungen von Medikamenten und ökonomische Aspekt
Cavity-enhanced optical Hall effect in two-dimensional free charge carrier gases detected at terahertz frequencies
The effect of a tunable, externally coupled Fabry-P\'{e}rot cavity to
resonantly enhance the optical Hall effect signatures at terahertz frequencies
produced by a traditional Drude-like two-dimensional electron gas is shown and
discussed in this communication. As a result, the detection of optical Hall
effect signatures at conveniently obtainable magnetic fields, for example by
neodymium permanent magnets, is demonstrated. An AlInN/GaN-based high electron
mobility transistor structure grown on a sapphire substrate is used for the
experiment. The optical Hall effect signatures and their dispersions, which are
governed by the frequency and the reflectance minima and maxima of the
externally coupled Fabry-P\'{e}rot cavity, are presented and discussed. Tuning
the externally coupled Fabry-P\'{e}rot cavity strongly modifies the optical
Hall effect signatures, which provides a new degree of freedom for optical Hall
effect experiments in addition to frequency, angle of incidence and magnetic
field direction and strength
Electron effective mass in AlGaN alloys determined by mid-infrared optical Hall effect
The effective electron mass parameter in Si-doped AlGaN is
determined to be from mid-infrared optical Hall
effect measurements. No significant anisotropy of the effective electron mass
parameter is found supporting theoretical predictions. Assuming a linear change
of the effective electron mass with the Al content in AlGaN alloys and
for GaN, an average effective electron mass of
can be extrapolated for AlN. The analysis of mid-infrared
spectroscopic ellipsometry measurements further confirms the two phonon mode
behavior of the E(TO) and one phonon mode behavior of the A(LO) phonon
mode in high-Al-content AlGaN alloys as seen in previous Raman scattering
studies
Characterization and financial impact of implantable cardioverter-defibrillator patients without interventions 5 years after implantation
Background: Implantable cardioverter defibrillators (ICD's) are increasingly used for primary and secondary prevention of sudden cardiac death. However, data on how many ICD patients indeed receive appropriate ICD therapy during long-term follow-up is scarce. Aim: The aim of our study was to determine the number of patients without appropriate ICD therapy 5 years after ICD implantation, to identify predicting factors, to assess the occurrence of late first ICD therapy and to quantify the financial impact of ICD therapy in a real-world setting. Design: Prospective observational study. Methods: We prospectively enrolled 322 consecutive ICD patients. Baseline data were collected at implantation and patients were followed for a median of 7.3 years (IQR 5.8-9.2 years). Time to first appropriate ICD therapy (either antitachycardia pacing or cardioversion) was documented. Results: Five years after implantation, 139 patients (43%) had not received appropriate ICD therapy. In multivariable analysis, a primary prevention indication and negative electrophysiological studies prior to ICD implantation were independent predictors of freedom from ICD therapy. Of the patients without ICD therapy, 5 years after implantation, 25% had experienced inappropriate ICD shocks. Two hundred and seven devices (1.5 devices per patient) were needed for the 139 patients without ICD intervention within 5 years, accounting for €31 784 per patient. During an additional follow-up of 3 years, 12% of the patients with unused ICD received a late first appropriate ICD therapy. Conclusions: About half of the ICD patients receive appropriate ICD therapy within 5 years after implantation. Furthermore, there is a significant proportion of patients receiving late first shocks after five initially uneventful year
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