Correlation between topological band character and chemical bonding in a Bi14Rh3I9\mathbf{Bi_{14}Rh_{3}I_{9}}-based family of insulators

Recently the presence of topologically protected edge-states in Bi$_{14}$Rh$_3$I$_9$ was confirmed by scanning tunnelling microscopy consolidating this compound as a weak 3D topological insulator (TI). Here, we present a density-functional-theory-based study on a family of TIs derived from the Bi$_{14}$Rh$_3$I$_9$ parent structure via substitution of Ru, Pd, Os, Ir and Pt for Rh. Comparative analysis of the band-structures throughout the entire series is done by means of a unified minimalistic tight-binding model that evinces strong similarity between the quantum-spin-Hall (QSH) layer in Bi$_{14}$Rh$_3$I$_9$ and graphene in terms of $p_z$-molecular orbitals. Topologically non-trivial energy gaps are found for the Ir-, Rh-, Pt- and Pd-based systems, whereas the Os- and Ru-systems remain trivial. Furthermore, the energy position of the metal $d$-band centre is identified as the parameter which governs the evolution of the topological character of the band structure through the whole family of TIs. The $d$-band position is shown to correlate with the chemical bonding within the QSH layers, thus revealing how the chemical nature of the constituents affects the topological band character

Durable, Yet Different: Monarchies in the Arab Spring

Over three years into the Arab Spring, the Middle East is characterized by a striking difference in durability between monarchies and republics. Beyond this difference, some significant gaps within the group of the eight Middle East monarchies have so far been overlooked. Drawing on the existing monarchy research, we first make the case that there were three distinct types of durable monarchies prior to the Arab Spring. Confronted with social and political crises, each type reacted differently to the challenges presented to them after 2011. While five "rentier" and "dynastic" Gulf monarchies (Bahrain, Kuwait, Qatar, Saudi Arabia and the UAE (United Arab Emirates)) mainly rely on material distribution and family rule, the non-oil "linchpins" of Jordan and Morocco, attracting additional external funds, undertook constitutional changes in an attempt at procedural legitimation. The Sultanate of Oman, however, falls in between. This "linchtier" monarchy used modest material cooptation, a selected personal reshuffing at the top of the regime as well as targeted institutional adaptations. We illustrate our findings with similarly structured brief case studies of the three prototypes of Qatar, Jordan and Oman

Functional analysis of the magnetosome island in Magnetospirillum gryphiswaldense: the mamAB operon is sufficient for magnetite biomineralization

Bacterial magnetosomes are membrane-enveloped, nanometer-sized crystals of magnetite, which serve for magnetotactic navigation. All genes implicated in the synthesis of these organelles are located in a conserved genomic magnetosome island (MAI). We performed a comprehensive bioinformatic, proteomic and genetic analysis of the MAI in Magnetospirillum gryphiswaldense. By the construction of large deletion mutants we demonstrate that the entire region is dispensable for growth, and the majority of MAI genes have no detectable function in magnetosome formation and could be eliminated without any effect. Only <25% of the region comprising four major operons could be associated with magnetite biomineralization, which correlated with high expression of these genes and their conservation among magnetotactic bacteria. Whereas only deletion of the mamAB operon resulted in the complete loss of magnetic particles, deletion of the conserved mms6, mamGFDC, and mamXY operons led to severe defects in morphology, size and organization of magnetite crystals. However, strains in which these operons were eliminated together retained the ability to synthesize small irregular crystallites, and weakly aligned in magnetic fields. This demonstrates that whereas the mamGFDC, mms6 and mamXY operons have crucial and partially overlapping functions for the formation of functional magnetosomes, the mamAB operon is the only region of the MAI, which is necessary and sufficient for magnetite biomineralization. Our data further reduce the known minimal gene set required for magnetosome formation and will be useful for future genome engineering approaches

Competence orientation in teaching from the perspetive of teachers and students

Mit der Einführung der nationalen Bildungsstandards ging ein Perspektivwechsel von der Input- zur Outputorientierung im Unterricht einher und es wurde die Grundlage für die Entwicklung eines an Kompetenzen orientierten Unterrichts geschaffen. In dieser Studie werden kompetenzorientierte Aktivitäten im Deutschunterricht aus Lehrkraft- sowie Schülerinnen- und Schülerperspektive empirisch erfasst. Die Übereinstimmung beider Perspektiven und der Zusammenhang der Häufigkeit kompetenzorientierter Aktivitäten im Unterricht mit der Kompetenz der Schülerinnen und Schüler werden im Rahmen von Strukturgleichungsmodellen untersucht. Die Ergebnisse zeigen (a) eine moderate Übereinstimmung beider Perspektiven und (b) positive Zusammenhänge kompetenzorientierter Aktivitäten mit der Lesekompetenz der Schülerinnen und Schüler im Fach Deutsch. Die Ergebnisse werden mit Bezug auf die Erfassung von Kompetenzorientierung als Merkmal von Unterricht diskutiert. (DIPF/Orig.)The introduction of National Educational Standards (Bildungsstandards) in Germany in 2004 has shifted the focus from input- towards output-oriented instruction and was accompanied by an advancement in competence-based instruction. This study provides an empirical investigation of activities that characterize competence-based instruction in German from both teacher and student perspectives. Agreement among these perspectives and the association of competence-based activities and student achievement were analyzed using structural equation modeling. We found a moderate agreement of teacher and student perspectives regarding competence-based activities and that student achievement correlates positively with competence-based activities. The paper also discusses the assessment of competence-based instruction as measured by frequency of competence-based activities. (DIPF/Orig.

El arrepentido entre prueba y error

En los últimos años, la figura del arrepentido ha recibido un mayor interés, que también se refleja en su inclusión –de manera explícita o implícita– en diferentes ordenamientos jurídicos. Junto con ello aumentaron las discusiones alrededor de esta nueva herramienta de investigación de delitos y una de las preguntas más recurrentes versa sobre si y cómo se puede justificar la implementación de la delación premiada en nuestros ordenamientos jurídicos. En especial, me interesan dos cosas. Por un lado, intentaré ordenar y agrupar o sistematizar las diferentes posturas de aceptación o rechazo de la figura y por el otro lado buscaré formas para evaluar la aceptabilidad de sus argumentos. Espero que estas observaciones tentativas tengan utilidad para un problema recurrente en el análisis de los procedimientos y la prueba: el riesgo de aceptar o no ciertos errores y su vinculación con los estándares de prueba

The crown witness between proof and error

In recent years, there has been a growing interest in the concept of the «Crown witness», which is also reflected in its inclusion - explicitly or implicitly - in different legal systems. Along with this, the discussions around this new tool of criminal investigation have increased, and one of the most recurrent questions is whether and how the implementation of the Crown witness in our legal systems can be justified. In particular, I am interested in two things. On the one hand, I will try to sort and group or systematise the different positions of justification o rejection of the Crown witness and, on the other hand, I will search for ways to assess their convincing force. I hope that these tentative observations will be useful for a recurrent problem in the analysis of procedures and evidence: the risk of accepting or not accepting certain errors and their link with standards of proof.En los últimos años, la figura del arrepentido ha recibido un mayor interés, que también se refleja en su inclusión –de manera explícita o implícita– en diferentes ordenamientos jurídicos. Junto con ello aumentaron las discusiones alrededor de esta nueva herramienta de investigación de delitos y una de las preguntas más recurrentes versa sobre si y cómo se puede justificar la implementación de la delación premiada en nuestros ordenamientos jurídicos. En especial, me interesan dos cosas. Por un lado, intentaré ordenar y agrupar o sistematizar las diferentes posturas de aceptación o rechazo de la figura y por el otro lado buscaré formas para evaluar la aceptabilidad de sus argumentos. Espero que estas observaciones tentativas tengan utilidad para un problema recurrente en el análisis de los procedimientos y la prueba: el riesgo de aceptar o no ciertos errores y su vinculación con los estándares de prueba

E-storybooks and paper storybooks for preschoolers: effects on attention, learning and engagement

The increasing availability of electronic storybooks (e-books) for preschoolers has raised a variety of concerns regarding their potential to distract children and diminish prereading skill acquisition as well as change the nature of the parent-child interaction during book reading. Alternatively, because e-books are delivered via popular mobile devices, it has been suggested that they might motivate children to read more, allow children to benefit from built-in reading aids, and increase their focused attention to story details. The current study investigated the utility of e-books for facilitating early literacy skills in a sample of 79 3 to 5-year-olds. Children read an e-book and paper storybook with an experimenter and were asked story comprehension questions following each book reading. Children then completed two measures of executive function (Day-Night Task and Digit Span Task) as well a measure of receptive vocabulary. Dependent measures were children’s (1) recall of factual and inferred story detail (2) duration of looking to book, adult, and off-task during reading, (3) engagement and communication during story reading. ANOVAs revealed that: (1) there was a significant increase in recall of story information across age, but no difference as a function of story format (2) all children were highly attentive during story reading but looked relatively more at the e-book than the paper book and more at the adult during the paper book reading (3) children were engaged with and communicated about both stories, but more so with the e-book than the paper book. The results of the current study suggest that carefully designed e-books support story comprehension similarly to paper books and also increase children’s engagement and communication during book reading