32 research outputs found
Synthese von Kurz- und LangzeitgedĂ€chtnisspanne : Experimentelle ĂberprĂŒfung eines mathematischen Modells
In acht Experimenten mit Variation des Stimulusmaterials und Probanden mit verschiedenen Muttersprachen wurden drei Invarianzhypothesen geprĂŒft. Die erste Invarianzhypothese zum KurzzeitgedĂ€chtnis wurde abgeleitet aus dem ErklĂ€rungsansatz zum WortlĂ€ngeneffekt innerhalb des ArbeitsgedĂ€chtnis-Modells von A. Baddeley. Postuliert wird eine invariante Haltbarkeit der GedĂ€chtnisspur, die sich formal aus dem Produkt von KurzzeitgedĂ€chtnisspanne und Artikulationszeit zusammensetzt. Diese Hypothese wird einer zweiten Invarianzhypothese zum KurzzeitgedĂ€chtnis gegenĂŒber gestellt: Experimentell wurde in einer Studie von Dosher und Ma zum Phonologischen Ăhnlichkeitseffekt eine konstante Dauer der Gesamtwiedergabe-Zeit bei der Reproduktion in einem GedĂ€chtnistest festgestellt, die durch das Produkt von KurzzeitgedĂ€chtnisspanne und Reproduktionszeit pro Item formalisiert werden kann. Die dritte Invarianzhypothese, die modifizierte Total-Time-Hypothese (mTTH), verbindet Kurz- und LangzeitgedĂ€chtnisspanne. Angenommen wird, erstens, ein hyperbolischer Anstieg aufgenommener Information mit der Lernzeit, wenn der insgesamt zu verarbeitende Informationsgehalt die KapazitĂ€t des KurzzeitgedĂ€chtnisses ĂŒberschreitet, und, zweitens, eine Ăquivalenz zwischen Asymptote dieser Lernfunktion und der KurzzeitgedĂ€chtnisspanne in bit. Die Ergebnisse sprechen fĂŒr die GĂŒltigkeit der Invarianzhypothese von Baddeley. Die Invarianzhypothese nach Dosher und Ma konnte nicht universell bestĂ€tigt werden: in AbhĂ€ngigkeit der Muttersprache der Probanden bestanden systematische Unterschiede in der Gesamtwiedergabe-Zeit. Im Vergleich dieser beiden Hypothesen erwies sich die Reproduktionszeit als besserer PrĂ€diktor der KurzzeitgedĂ€chtnisspanne als die Artikulationszeit. Die GĂŒltigkeit der mTTH wurde in allen Experimenten nachgewiesen, doch ergab sich spezifisch bei Zahlenmaterial keine Ăquivalenz zwischen Asymptote und KurzzeitgedĂ€chtnisspanne. FĂŒr Wortmaterialien dagegen hatte die Ăquivalenzhypothese Bestand
Extended point defects in crystalline materials: Ge and Si
B diffusion measurements are used to probe the basic nature of
self-interstitial 'point' defects in Ge. We find two distinct self-interstitial
forms - a simple one with low entropy and a complex one with entropy ~30 k at
the migration saddle point. The latter dominates diffusion at high temperature.
We propose that its structure is similar to that of an amorphous pocket - we
name it a 'morph'. Computational modelling suggests that morphs exist in both
self-interstitial and vacancy-like forms, and are crucial for diffusion and
defect dynamics in Ge, Si and probably many other crystalline solids
A Mutational Hotspot in the 2B Domain of Human Hair Basic Keratin 6 (hHb6) in Monilethrix Patients
Monilethrix is an inherited hair dystrophy in which affected, fragile, hairs have an unique beaded morphology. Ultrastructural studies suggest a defect in filament structure in the cortex of the hair, and the hard keratins of hair and nail are thus candidate genes. In several families with autosomal dominant monilethrix, the disorder has been linked to the type II keratin gene cluster at chromosome 12q13. Recently, causative mutations in the critical helix termination motif in the 2B domain of the human hair basic keratin 6 (hHb6) have been identified. We now report the results of sequencing this domain in 13 unrelated families or cases with monilethrix. Five of the 13 had the same mutation as previously found, a G to A transversion leading to a lysine for glutamic acid substitution (E413K) in the 2B domain (residue 117 of the 2B helix) of hHb6. The mutation was confirmed by a restriction fragment length polymorphism assay developed for this purpose, and, as this mutation is evidently a common cause of the syndrome, for use in screening other cases. In eight families or cases, however, including three in whom linkage data are consistent with a defect at the type II keratin locus, no mutation was found in this domain of hHb6
S1 Guideline onychomycosis
Onychomycosis is a fungal infection of the fingernails and toenails. In Europe, tinea unguium is mainly caused by dermatophytes. The diagnostic workup comprises microscopic examination, culture and/or molecular testing (nail scrapings). Local treatment with antifungal nail polish is recommended for mild or moderate nail infections. In case of moderate to severe onychomycosis, oral treatment is recommended (in the absence of contraindications). Treatment should consist of topical and systemic agents. The aim of this update of the German S1 guideline is to simplify the selection and implementation of appropriate diagnostics and treatment. The guideline was based on current international guidelines and the results of a literature review conducted by the experts of the guideline committee. This multidisciplinary committee consisted of representatives from the German Society of Dermatology (DDG), the GermanâSpeaking Mycological Society (DMykG), the Association of German Dermatologists (BVDD), the German Society for Hygiene and Microbiology (DGHM), the German Society of Pediatric and Adolescent Medicine (DGKJ), the Working Group for Pediatric Dermatology (APD) and the German Society for Pediatric Infectious Diseases (DGPI). The Division of Evidenceâbased Medicine (dEBM) provided methodological assistance. The guideline was approved by the participating medical societies following a comprehensive internal and external review
Influence of boron-interstitials clusters on hole mobility degradation in high dose boron-implanted ultrashallow junctions
International audienceHole mobility degradation has been studied in high-dose boron-implanted ultrashallow junctions containing high concentrations of boron-interstitial clusters BICs, combining an empirical method based on the self-consistent interpretation of secondary-ion-mass spectrometry SIMS and Hall measurements and liquid-nitrogen LN 2 to room temperature RT hole mobility measurements. It has been found that BICs act as independent scattering centers which have a strong impact on hole mobility in addition to the other scattering mechanisms such as lattice and impurities scattering. A mobility degradation coefficient has been introduced, which gives information on the mobility degradation level in the analyzed junctions. In the case of very high concentrations of BICs containing a boron density up to 8 10 14 cm â2 , measured hole mobilities were found to be 40% lower than corresponding theoretical values. BICs dissolution through multiple Flash anneals at high temperature 1300 ° C reduces the observe mobility degradation
Overlayer stress effects on defect formation in Si and Ge
International audiencePoint-defect formation energies in bulk crystalline materials such as Si and Ge are material specific quantities defined for the case of formation at a free surface, but in many cases of technological interest, point defects are formed at the interface between the crystalline substrate and a strained material overlayer. Here the energy cost of generating a bulk point defect at the overlayer/substrate interface is modified by the stress interaction during defect formation, leading to an effective supersaturation or undersaturation in the bulk, relative to the 'equilibrium' concentration expected for the case of a free surface. This in turn impacts on diffusion, defect formation and activation of dopant impurities in the substrate. We present current experimental evidence for this phenomenon, based on studies of B diffusion under tensile-strained nitride layers, and discuss the likely implications for dopant activation in Si and Ge
Testing the diagnostic value of electrical ear canal stimulation in cochlear implant candidates by functional magnetic resonance imaging
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugÀnglich. - This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively. - PrinmÀrausgabe im Karger-Verlag (www.karger.com/?doi=10.1159/000124276) erschienen