Insights from surface enhanced resonance Raman spectroscopy and QM/MM calculations

Understanding the coupling between heme reduction and proton translocation in cytochrome c oxidase (CcO) is still an open problem. The propionic acids of heme a3 have been proposed to act as a proton loading site (PLS) in the proton pumping pathway, yet this proposal could not be verified by experimental data so far. We have set up an experiment where the redox states of the two hemes in CcO can be controlled via external electrical potential. Surface enhanced resonance Raman (SERR) spectroscopy was applied to simultaneously monitor the redox state of the hemes and the protonation state of the heme propionates. Simulated spectra based on QM/MM calculations were used to assign the resonant enhanced CH2 twisting modes of the propionates to the protonation state of the individual heme a and heme a3 propionates respectively. The comparison between calculated and measured H2OD2O difference spectra allowed a sound band assignment. In the fully reduced enzyme at least three of the four heme propionates were found to be protonated whereas in the presence of a reduced heme a and an oxidized heme a3 only protonation of one heme a3 propionates was observed. Our data supports the postulated scenario where the heme a3 propionates are involved in the proton pathway

Renewable energy resource assessment

© The Author(s) 2019. Literature overview of published global and regional renewable energy potential estimates. This section provides definitions for different types of RE potentials and introduces a new category, the economic renewable energy potential in space constrained environments. The potential for utility scale solar and onshore wind in square kilometre and maximum possible installed capacity (in GW) are provided for 75 different regions. The results set the upper limits for the deployment of solar- and wind technologies for the development of the 2.0 °C and 1.5 °C energy pathways

Measuring instructional quality in mathematics education

International audienceInstructional research has recently become more important within the framework of teaching effectiveness research. Various instruments have been developed within this research discipline in order to gain a better insight of what is really happening in the classroom. Most of these instruments mainly focus on generic aspects of instructional quality. In this paper we first describe a subject-specific dimension of instructional quality. Second, we show how these subject-specific aspects could be measured empirically with a standardized observational instrument. The results point out both good interrater agreement and satisfying reliability measures. The presented observational instrument has been developed within the study TEDS-instruct in which relations to teachers' competencies and students' achievement are analyzed

Fachspezifische Unterrichtsqualität im Mathematikunterricht

In der empirischen Unterrichtsforschung in Deutschland hat die Frage nach der Fachspezifizität von Unterrichtsqualität bislang wenig Beachtung gefunden. Es haben sich drei Basisdimensionen (kognitive Aktivierung, konstruktive Unterstützung, Klassenführung) von Unterrichtsqualität etabliert, die letztere in verschiedenen Fächern gleichermaßen beschreiben sollen (z.B. Klieme & Rakoczy, 2008). Hierbei ist fraglich, inwieweit relevante Fachspezifika von Mathematikunterricht ausreichend berücksichtigt werden. Blum und andere (2006) fordern aus diesem Grund neben den drei asisdimensionen eine "fachlich gehaltvolle Gestaltung" von Mathematikunterricht als zusätzlichen Qualitätsaspekt. Insbesondere existiert nach unserem Kenntnisstand kein standardisiertes Instrument zur Erfassung der Qualität von Mathematikunterricht, das neben den fachübergreifenden Basisdimensionen fachspezifische Qualitätsaspekte erhebt, ohne sich dabei auf einen bestimmten mathematischen Inhaltsbereich zu beschränken. Ausgehend von diesem Desiderat wird in dem vorliegenden Beitrag die Fragestellung untersucht, inwieweit sich eine fachspezifische Dimension von Unterrichtsqualität neben den drei etablierten Basisdimensionen konzeptualisieren und mit einem standardisierten Beobachtungsinstrument erfassen lässt