Synthese von Kurz- und Langzeitgedächtnisspanne : Experimentelle Überprüfung eines mathematischen Modells

In acht Experimenten mit Variation des Stimulusmaterials und Probanden mit verschiedenen Muttersprachen wurden drei Invarianzhypothesen geprüft. Die erste Invarianzhypothese zum Kurzzeitgedächtnis wurde abgeleitet aus dem Erklärungsansatz zum Wortlängeneffekt innerhalb des Arbeitsgedächtnis-Modells von A. Baddeley. Postuliert wird eine invariante Haltbarkeit der Gedächtnisspur, die sich formal aus dem Produkt von Kurzzeitgedächtnisspanne und Artikulationszeit zusammensetzt. Diese Hypothese wird einer zweiten Invarianzhypothese zum Kurzzeitgedächtnis gegenüber gestellt: Experimentell wurde in einer Studie von Dosher und Ma zum Phonologischen Ähnlichkeitseffekt eine konstante Dauer der Gesamtwiedergabe-Zeit bei der Reproduktion in einem Gedächtnistest festgestellt, die durch das Produkt von Kurzzeitgedächtnisspanne und Reproduktionszeit pro Item formalisiert werden kann. Die dritte Invarianzhypothese, die modifizierte Total-Time-Hypothese (mTTH), verbindet Kurz- und Langzeitgedächtnisspanne. Angenommen wird, erstens, ein hyperbolischer Anstieg aufgenommener Information mit der Lernzeit, wenn der insgesamt zu verarbeitende Informationsgehalt die Kapazität des Kurzzeitgedächtnisses überschreitet, und, zweitens, eine Äquivalenz zwischen Asymptote dieser Lernfunktion und der Kurzzeitgedächtnisspanne in bit. Die Ergebnisse sprechen für die Gültigkeit der Invarianzhypothese von Baddeley. Die Invarianzhypothese nach Dosher und Ma konnte nicht universell bestätigt werden: in Abhängigkeit der Muttersprache der Probanden bestanden systematische Unterschiede in der Gesamtwiedergabe-Zeit. Im Vergleich dieser beiden Hypothesen erwies sich die Reproduktionszeit als besserer Prädiktor der Kurzzeitgedächtnisspanne als die Artikulationszeit. Die Gültigkeit der mTTH wurde in allen Experimenten nachgewiesen, doch ergab sich spezifisch bei Zahlenmaterial keine Äquivalenz zwischen Asymptote und Kurzzeitgedächtnisspanne. Für Wortmaterialien dagegen hatte die Äquivalenzhypothese 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 German‐Speaking 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 Evidence‐based 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 −2 , 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 zugänglich. - 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. - Prinmärausgabe im Karger-Verlag (www.karger.com/?doi=10.1159/000124276) erschienen