Dark-adapted red flash ERGs in healthy adults

Purpose: The x-wave of the dark-adapted (DA) ERG to a red flash reflects DA cone function. This exploratory study of healthy adults aimed to investigate changes in the DA red ERG with flash strength and during dark adaptation to optimise visualisation and therefore quantification of the x-wave. Methods: The effect of altering red flash strength was investigated in four subjects by recording ERGs after 20 minutes dark adaptation to red flashes (0.2–2.0 cd s m-2) using skin electrodes and natural pupils. The effect of dark adaptation duration was investigated in 16 subjects during 20 minutes in the dark, by recording DA 1.5 red ERGs at 1, 2, 3, 4, 5, 10, 15 and 20 minutes. Results: For a dark adaption period of 20 minutes, the x-wave was more clearly visualised to weaker (< 0.6 cd s m-2) red flash strengths: to stronger flashes it became obscured by the b-wave. For red flashes of 1.5 cd s m-2, the x-wave was most prominent in ERGs recorded after 1–5 minutes of dark adaptation: with longer dark-adaptation, it was subsumed into the b-wave’s rising edge. Conclusions: This small study suggests that x-wave visibility in healthy subjects after 20 minutes dark adaptation is improved by using flashes weaker than around 0.6 cd s m-2; for flash strengths of 1.5 cd s m-2, x-wave visibility is enhanced by recording after only around 5 minutes of dark adaptation. No evidence was found that interim red flash ERGs affecting the dark-adapted state of the normal retina

Multi-wall carbon nanotubes as quantum dots

We have measured the differential conductance dI/dV of individual multi-wall carbon nanotubes (MWNT) of different lengths. A cross-over from wire-like (long tubes) to dot-like (short tubes) behavior is observed. dI/dV is dominated by random conductance fluctuations (UCF) in long MWNT devices (L=2...7 $\mu m$), while Coulomb blockade and energy level quantization are observed in short ones (L=300 nm). The electron levels of short MWNT dots are nearly four-fold degenerate (including spin) and their evolution in magnetic field (Zeeman splitting) agrees with a g-factor of 2. In zero magnetic field the sequential filling of states evolves with spin S according to S=0 -> 1/2 -> 0... In addition, a Kondo enhancement of the conductance is observed when the number of electrons on the tube is odd.Comment: 10 pages, 4 figure

Commodities and cognition

A commentary on "An enquiry concerning the nature of conceptual categories: a case-study on the social dimension of human cognition", by John Stewart (2014)in 'Frontiers in Psychology', Vol.5

[Rezension zu:] David von Mayenburg: Kriminologie und Strafrecht zwischen Kaiserreich und Nationalsozialismus. Hans von Hentig (1887-1974) (= Rheinische Schriften zur Rechtsgeschichte; Bd. 1), Baden-Baden: NOMOS 2006, 492 S., ISBN 978-3-8329-1883-5, EUR 89,00

Hans von Hentig war ein impulsiver Abenteurer mit wenig Respekt vor Autorität. Und er war ein extrem schreibfreudiger Wissenschaftler, der zu den Begründern einer modernen, durch die Verbindung juristischer und medizinisch-psychologischer Kenntnisse und Zugänge bestimmten Kriminologie gehörte. Hans von Hentig wurde 1887 als Sohn des Rechtsanwalts Otto Hentig geboren. Dieser hatte zunächst in Berlin praktiziert, bevor er als Spezialist für Wirtschaftsrecht 1893 zum Verwalter der Güter Karl Egon IV. zu Fürstenberg und 1900 zum Staatsminister des Herzogtums Sachsen Coburg und Gotha wurde; letzteres Amt brachte der Familie die Nobilitierung ein. ..

Higgs Radiation off Top Quarks at the Tevatron and the LHC

Higgs bosons can be searched for in the channels $p\bar p/pp\to t\bar tH+X$ at the Tevatron and the LHC. We have calculated the QCD corrections to these processes in the Standard Model at next-to-leading order. The higher-order corrections reduce the renormalization and factorization scale dependence considerably and stabilize the theoretical predictions for the cross sections. At the central scale $\mu=(2m_t+M_H)/2$ the properly defined $K$ factors are slightly below unity for the Tevatron ($K \sim 0.8$) and slightly above unity for the LHC ($K \sim 1.2$).Comment: 5 pages, latex, 2 figure

Friedrich Hamm zum Gedenken : 12.4.1891 - 4.7.1972

Dr. phil. nat. FRIEDRICH HAMM wurde in Osnabrück, Krahnstraße 1, als Sohn des Sanitätsrates Dr. med. et Dr. phil. HERMANN HAMM und seiner Frau MARIA BRINKMANN-TO BROXEN am 12. April 1891 - einem Sonntag - geboren. Er überlebte seine 5 Geschwister, die alle vor dem Erreichen des 1. Lebensjahres starben