Inhalte von Regeln und Klassenmanagement

Regeln leisten einen wichtigen Beitrag zu einem erfolgreichen Unterricht, in dem wenig gestört und gut mitgearbeitet wird. Allerdings beachtete die Forschung bisher kaum, welche Inhalte in den Regeln thematisiert werden und wie die inhaltliche Gestaltung von Regeln mit dem Klassenmanagement zusammenhängt. Hier liegt der Fokus dieses Artikels. Anhand von Lehrpersonen-Daten (N=605) und Schüler-Daten (N=923) wird gezeigt, dass sich mit «Sozialer Interaktion» sowie «Ruhe, Ordnung» zwei Bereiche abzeichnen, bei denen ein Regelungsbedarf vorliegt. Eine einseitige Fokussierung auf Ordnungsregeln geht hingegen häufig mit einem höheren Ausmass an Unterrichtsstörungen einher. Abschliessend wird in einem Modell die indirekte Natur dieser Relation veranschaulicht und die Rolle der intermittierenden Variablen – insbesondere der Lehrperson-Schüler-Beziehung – diskutiert. (DIPF/Orig.)Rules make an important contribution to successful teaching where there is little disruption and a high level of participation. However, so far research has barely paid attention to the contents of these rules and to their relationship to the classroom management. This article highlights with the help of teachers’ (N=605) and pupils’ (N=923) data these questions. It identifies aspects (social interaction, silence and order) where regulation is needed. But an unbalanced focusing on rules of order is often accompanied by a higher degree of disruption during classes. Finally, the indirect nature of this correlation is illustrated in a model and the role of the intermittent variables (especially the relationship between teachers and pupils) is discussed. (DIPF/Orig.

Late metal-silicate separation on the IAB parent asteroid: Constraints from combined W and Pt isotopes and thermal modelling

The short-lived $^{182}$Hf-$^{182}$W decay system is a powerful chronometer for constraining the timing of metal-silicate separation and core formation in planetesimals and planets. Neutron capture effects on W isotopes, however, significantly hamper the application of this tool. In order to correct for neutron capture effects, Pt isotopes have emerged as a reliable in-situ neutron dosimeter. This study applies this method to IAB iron meteorites, in order to constrain the timing of metal segregation on the IAB parent body. The $\epsilon^{182}$W values obtained for the IAB iron meteorites range from -3.61 $\pm$ 0.10 to -2.73 $\pm$ 0.09. Correlating $\epsilon^{\mathrm{i}}$Pt with $^{182}$W data yields a pre-neutron capture $^{182}$W of -2.90 $\pm$ 0.06. This corresponds to a metal-silicate separation age of 6.0 $\pm$ 0.8 Ma after CAI for the IAB parent body, and is interpreted to represent a body-wide melting event. Later, between 10 and 14 Ma after CAI, an impact led to a catastrophic break-up and subsequent reassembly of the parent body. Thermal models of the interior evolution that are consistent with these estimates suggest that the IAB parent body underwent metal-silicate separation as a result of internal heating by short-lived radionuclides and accreted at around 1.4 $\pm$ 0.1 Ma after CAIs with a radius of greater than 60 km.Comment: 11 pages, 8 figures, 2 tables; open access article under the CC BY-NC-ND license (see http://creativecommons.org/licenses/by-nc-nd/4.0/

The role of civil society in civilian protection and conflict transformation during armed conflict: the case study of Idlib (Syria)

Treball final de Màster Universitari en Estudis internacionals de Pau, Conflictes i Desenvolupament. Codi: SBG119. Curs acadèmic 2015-2016This research examines the link between civilian protection and conflict transformation and what role civil society plays in it. The qualitative research uses the case study of Idlib, Syria, to show how civil society organizations (CSOs) apply traditional and other nonviolent tools to deal with violence and conflicts on a local level. The findings demonstrate a certain lack of awareness of most CSOs of their transformative potential. The thesis proposes an analytical framework that allows to link civilian protection to conflict transformation and elicits alternative approaches for supporting local CSOs in their efforts in protection and building peace

Impact splash chondrule formation during planetesimal recycling

Chondrules are the dominant bulk silicate constituent of chondritic meteorites and originate from highly energetic, local processes during the first million years after the birth of the Sun. So far, an astrophysically consistent chondrule formation scenario, explaining major chemical, isotopic and textural features, remains elusive. Here, we examine the prospect of forming chondrules from planetesimal collisions. We show that intensely melted bodies with interior magma oceans became rapidly chemically equilibrated and physically differentiated. Therefore, collisional interactions among such bodies would have resulted in chondrule-like but basaltic spherules, which are not observed in the meteoritic record. This inconsistency with the expected dynamical interactions hints at an incomplete understanding of the planetary growth regime during the protoplanetary disk phase. To resolve this conundrum, we examine how the observed chemical and isotopic features of chondrules constrain the dynamical environment of accreting chondrite parent bodies by interpreting the meteoritic record as an impact-generated proxy of planetesimals that underwent repeated collision and reaccretion cycles. Using a coupled evolution-collision model we demonstrate that the vast majority of collisional debris feeding the asteroid main belt must be derived from planetesimals which were partially molten at maximum. Therefore, the precursors of chondrite parent bodies either formed primarily small, from sub-canonical aluminum-26 reservoirs, or collisional destruction mechanisms were efficient enough to shatter planetesimals before they reached the magma ocean phase. Finally, we outline the window in parameter space for which chondrule formation from planetesimal collisions can be reconciled with the meteoritic record and how our results can be used to further constrain early solar system dynamics.Comment: 20 pages, 11 figures, 2 tables; accepted for publication in Icarus; associated blog article at goo.gl/5bDqG

Freshness-indices of roasted coffee : monitoring the loss of freshness for single serve capsules and roasted whole beans in different packaging

With the growing demand for high-quality coffee, it is becoming increasingly important to establish quantitative measures of the freshness of coffee, or the loss thereof, over time. Indeed, freshness has become a critical quality criterion in the specialty coffee scene, where the aim is to deliver the most pleasant flavor in the cup, from highest quality beans. A series of intensity ratios of selected volatile organic compounds (VOC) in the headspace of coffee (by gas chromatography–mass spectrometry) were revisited, with the aim to establish robust indicators of freshness of coffee – called freshness indices. Roasted whole beans in four different packaging materials and four commercial capsule systems from the Swiss market were investigated over a period of up to one year of storage time. These measurements revealed three types of insight. First, a clear link between barrier properties of the packaging material and the evolution of selected freshness indices was observed. Packaging materials that contain an aluminum layer offer better protection. Second, processing steps prior to packaging are reflected in the absolute values of freshness indices. Third, differences in the standard deviations of freshness-indices for single serve coffee capsule systems are indicative of differences in the consistency among systems, consistency being an important quality attribute of capsules

The formation of Jupiter by hybrid pebble-planetesimal accretion

The standard model for giant planet formation is based on the accretion of solids by a growing planetary embryo, followed by rapid gas accretion once the planet exceeds a so-called critical mass. The dominant size of the accreted solids (cm-size particles named pebbles or km to hundred km-size bodies named planetesimals) is, however, unknown. Recently, high-precision measurements of isotopes in meteorites provided evidence for the existence of two reservoirs in the early Solar System. These reservoirs remained separated from ~1 until ~ 3 Myr after the beginning of the Solar System's formation. This separation is interpreted as resulting from Jupiter growing and becoming a barrier for material transport. In this framework, Jupiter reached ~20 Earth masses within ~1 Myr and slowly grew to ~50 Earth masses in the subsequent 2 Myr before reaching its present-day mass. The evidence that Jupiter slowed down its growth after reaching 20 Earth masses for at least 2 Myr is puzzling because a planet of this mass is expected to trigger fast runaway gas accretion. Here, we use theoretical models to describe the conditions allowing for such a slow accretion and show that Jupiter grew in three distinct phases. First, rapid pebble accretion brought the major part of Jupiter's core mass. Second, slow planetesimal accretion provided the energy required to hinder runaway gas accretion during 2 Myr. Third, runaway gas accretion proceeded. Both pebbles and planetesimals therefore have an important role in Jupiter's formation.Comment: Published in Nature Astronomy on August 27, 201