Social climate: the subjective experience of pupils about school and class environment

Bei der Interpretation menschlichen Verhaltens erlangen ökologische Variablen zunehmende Bedeutung. Eine dieser Variablen - das Sozialklima - reflektiert das subjektive Erleben schulischer Umwelt als Gemeinsamkeit zwischen den Schülern einer Klasse oder Schule. Das Sozialklima wurde vorwiegend durch Fragebogen erhoben. Die bisherigen Forschungsergebnisse zeigen, daß (a) der Einfluß des Lehrers und der von Kontextvariablen auf das Sozialklima zu wenig untersucht worden ist, (b) individuelle Schülermerkmale den größten Einfluß auf die Umweltwahrnehmung haben, (c) die Häufigkeitsverteilung von Individualmerkmalen eine maßgebliche Rolle spielt, und (d) daß das Sozialklima ein guter Prädiktor für Schulleistungen ist. Wünschenswert sind Längsschnittuntersuchungen, die eine dringend notwendige Kausalanalyse des Sozialklimas möglich machen. (DIPF/Orig.)In explaining human behavior ecological variables receive growing importance. One of these variables - the social-emotional climate - reflects common subjective experiences of pupils about school or class environment. Up to now the climate was mainly assessed by questionnaires. The empirical results show that (a) the influence of the teacher and of context variables are seriously neglected, (b) the individual characteristics of pupils have the greatest influence on the perception of school environment, (c) the frequency distribution of individual variables plays a very important role, (d) climate is a good predictor for school performance. It is desirable to carry out longitudinal studies to get indispensable causal interpretations for climate as an independent and dependent construct

Laserspektroskopische Untersuchungen laminarer Grenzschichten turbulenter Strömungen mit Hilfe molekularer Marker

Im Rahmen dieser Arbeit wurde zunächst ein Strömungskanal zur Untersuchung einer statistisch stationären turbulenten Strömung aufgebaut. Der Kanal besteht aus einem Beobachtungsbereich einer Länge von 18 cm, der so konstruiert ist, dass die Bodenplatte des Kanals problemlos ausgetauscht und durch Platten unterschiedlicher Beschaffenheit ersetzt werden kann. Durch ein sehr großes Seitenverhältnis (Faktor 12) ändert sich die Strömungsgeschwindigkeit nur in Abhängigkeit der Höhe über der Bodenplatte. In dem Strömungskanal lassen sich turbulente Luft- und Stickstoffströmungen bei Reynolds-Zahlen zwischen Re = 6000 und 15500 mit korrespondierenden mittleren Maximalgeschwindigkeiten zwischen 18 und 47 m/s realisieren. Unter Anwendung der am Physikalisch-Chemischen Institut entwickelten Strömungsmarkierungstechnik wurden, basierend auf der Erzeugung von linienförmigen Stickstoffmonoxid-Strukturen, verschiedene turbulente Strömungen untersucht. Die bestehende Technik wurde dahingehend weiterentwickelt, dass die Erzeugung einer Struktur aus drei parallelen NO-Linien möglich ist. Ein detaillierter Vergleich der experimentellen Ergebnisse mit einer am Interdisziplinären Zentrum für wissenschaftliches Rechnen der Universität Heidelberg ausgeführten direkten numerischen Simulation (DNS) zeigt eine sehr gute Übereinstimmung der Verschiebung und der großskaligen Verformung der erzeugten Linienstrukturen durch die turbulente Strömung. Zum Vergleich der in der Simulation initialisierten Turbulenz mit der im Experiment realisierten Strömung wurden simultane Messungen der Linienverschiebung mit Hilfe der Strömungsmarkierungstechnik und des 2-dimensionalen Strömungsgeschwindigkeitsfeldes unter Einsatz der Particle Image Velocimetry (PIV) durchgeführt. Um die in der DNS dargestellte zeitliche Entwicklung der Turbulenzstrukturen experimentell verifizieren zu können, wurde anschließend ein System zum mehrfachen Nachweis einer erzeugten Stickstoffmonoxid-Linie aufgebaut. Experimente zum doppelten Nachweis einer Linienstruktur ermöglichen einen Vergleich der zeitlichen Entwicklung der Linienstruktur zwischen Experiment und Simulation. Die zeitliche Entwicklung selbst kleinskaliger Strukturänderungen lässt sich mit dem aufgebauten System erfolgreich nachweisen. Das Verfahren ermöglicht außerdem die Bestimmung der Dicke der Geschwindigkeitsgrenzschicht, d.h. des Bereiches der größten Geschwindigkeitsänderung zwischen Wand und turbulenter Pfropfenströmung in der Kanalmitte. Aus dem beobachteten Transport der Linie in dieser Geschwindigkeitsgrenzschicht wurde die Verteilung der Strömungsgeschwindigkeiten in Abhängigkeit vom Wandabstand bestimmt. Parallel dazu wurden unterschiedliche Verfahren zur inhomogenen Strömungsdotierung mit molekularen Tracern angewandt. Die Verfahren ermöglichen zum einen, ausschließlich die Grenzschicht mit Naphthalin und Stickstoffmonoxid zu markieren und zum anderen eine Wolke aus Stickstoffmonoxid-Molekülen in der turbulenten Strömung zu verfolgen. Durch die in der Strömung entstehenden Konzentrationsgradienten erlauben diese Verfahren jeweils die Identifizierung der reibungsbestimmten Grenzschicht direkt an der Wand, eine Visualisierung des diffusiven Spezies-Transportes durch diese Grenzschicht hindurch und eine Visualisierung des turbulenten Spezies-Transportes aus dieser Grenzschicht in die turbulente Strömung hinein

Evidence from Focal Brain Lesions

Neuroimaging and neuropsychological experiments suggest that modality- preferential cortices, including motor- and somatosensory areas, contribute to the semantic processing of action related concrete words. Still, a possible role of sensorimotor areas in processing abstract meaning remains under debate. Recent fMRI studies indicate an involvement of the left sensorimotor cortex in the processing of abstract-emotional words (e.g., “love”) which resembles activation patterns seen for action words. But are the activated areas indeed necessary for processing action-related and abstract words? The current study now investigates word processing in two patients suffering from focal brain lesion in the left frontocentral motor system. A speeded Lexical Decision Task on meticulously matched word groups showed that the recognition of nouns from different semantic categories – related to food, animals, tools, and abstract-emotional concepts – was differentially affected. Whereas patient HS with a lesion in dorsolateral central sensorimotor systems next to the hand area showed a category-specific deficit in recognizing tool words, patient CA suffering from lesion centered in the left supplementary motor area was primarily impaired in abstract-emotional word processing. These results point to a causal role of the motor cortex in the semantic processing of both action-related object concepts and abstract-emotional concepts and therefore suggest that the motor areas previously found active in action-related and abstract word processing can serve a meaning-specific necessary role in word recognition. The category-specific nature of the observed dissociations is difficult to reconcile with the idea that sensorimotor systems are somehow peripheral or ‘epiphenomenal’ to meaning and concept processing. Rather, our results are consistent with the claim that cognition is grounded in action and perception and based on distributed action perception circuits reaching into modality-preferential cortex

Adults with autism spectrum condition have atypical perception of ambiguous figures when bottom-up and top-down interactions are incongruous.

We examined the perception of an ambiguous squares stimulus evoking bistable perception in a sample of 31 individuals with autistic spectrum condition and 22 matched typical adults. The perception of the ambiguous figure was manipulated by adaptation to unambiguous figures and/or by placing the ambiguous figure into a context of unambiguous figures. This resulted in four conditions testing the independent and combined (congruent and incongruent) manipulations of adaptation (bottom-up) and spatial context (top-down) effects. The strength of perception, as measured by perception of the first reported orientation of the ambiguous stimulus, was affected comparably between groups. Nevertheless, the strength of perception, as measured by perceptual durations, was affected differently between groups: the perceptual effect was strongest for the autistic spectrum condition group when combined bottom-up and top-down conditions were congruent. In contrast, the strength of the perceptual effect in response to the same condition in the typical adults group was comparable to the adaptation, but stronger than both the context and the incongruent combined bottom-up and top-down conditions. Furthermore, the context condition was stronger than the incongruent combined bottom-up and top-down conditions for the typical adults group. Thus, our findings support the view of stimulus-specific top-down modulation in autistic spectrum condition

Detecting the Psychosis Prodrome Across High-Risk Populations Using Neuroanatomical Biomarkers

To date, the MRI-based individualized prediction of psychosis has only been demonstrated in single-site studies. It remains unclear if MRI biomarkers generalize across different centers and MR scanners and represent accurate surrogates of the risk for developing this devastating illness. Therefore, we assessed whether a MRI-based prediction system identified patients with a later disease transition among 73 clinically defined high-risk persons recruited at two different early recognition centers. Prognostic performance was measured using cross-validation, independent test validation, and Kaplan-Meier survival analysis. Transition outcomes were correctly predicted in 80% of test cases (sensitivity: 76%, specificity: 85%, positive likelihood ratio: 5.1). Thus, given a 54-month transition risk of 45% across both centers, MRI-based predictors provided a 36%-increase of prognostic certainty. After stratifying individuals into low-, intermediate-, and high-risk groups using the predictor's decision score, the high- vs low-risk groups had median psychosis-free survival times of 5 vs 51 months and transition rates of 88% vs 8%. The predictor's decision function involved gray matter volume alterations in prefrontal, perisylvian, and subcortical structures. Our results support the existence of a cross-center neuroanatomical signature of emerging psychosis enabling individualized risk staging across different high-risk populations. Supplementary results revealed that (1) potentially confounding between-site differences were effectively mitigated using statistical correction methods, and (2) the detection of the prodromal signature considerably depended on the available sample sizes. These observations pave the way for future multicenter studies, which may ultimately facilitate the neurobiological refinement of risk criteria and personalized preventive therapies based on individualized risk profiling tool

Cross-sectional, descriptive study of Chagas disease among citizens of Bolivian origin living in Munich, Germany

PURPOSE: Chagas disease (CD) has become a global health issue mainly due to migration. Germany lacks surveillance data and is home to a large Latin American immigrant population. Recognising that Bolivia is the country with the highest CD prevalence in Latin America, this cross-sectional, descriptive pilot study investigated CD and associated factors among citizens of Bolivian origin living in Munich, Germany. METHODS: Participants completed a questionnaire in order to collect socioeconomic and health-related data. In addition, serology was performed. In case of positive serological tests, PCR diagnostic and clinical staging together with disease management was initiated. Qualitative research was conducted to identify personal and community barriers as well as strategies to increase CD awareness among the population at risk. RESULTS: Between June 2013 and June 2014, 43 people from Bolivia (or descendants) were enrolled. A total of 9.3% (4/43), of whom two women were of childbearing age, tested seropositive (ELISA and IFAT), and one also by PCR. For 2/4 positive participants, clinical evaluation was performed and the indeterminate form of CD was diagnosed. Knowledge about CD symptoms and ways of transmission were completely absent among 55.8% (24/43, 2/4 with CD) and 30.2% (13/43, 1/4 with CD) of participants, respectively. A total of 27.9% (12/43, 0/4 with CD) of participants had donated blood prior to the study, whereas 62.8% (27/43, 3/4 with CD) were motivated to donate blood in the future. The qualitative research identified lack of knowledge as well as stigma and fears related to CD. CONCLUSIONS: Despite the small number of participants, the prevalence of CD as well as the potential risk of non-vectorial transmission was alarming. Campaigns adapted for Latin American migrants as well as control strategies should be developed and put in place in order to prevent non-vectorial transmission and actively detect cases of CD in Germany.This study was supported through the Clinical Leave Programme (TI 07.001, grant to MP) and the MD Programme (TI 07.003, grant to MP and MH) by the German Center for Infection Research (DZIF). The University of Munich (LMU) contributed through the programme ‘Lehre@LMU’ (grants to MP and CS), and Mundo Sano provided financial and human resources to plan the informational approach to reach the Bolivian community living in Munich and to design and perform the qualitative research.S

Super-heavy fermion material as metallic refrigerant for adiabatic demagnetization cooling

Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, as the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with $^3$He gas are widely used for cooling below 1 Kelvin. However, usage of the gas is being increasingly difficult due to the current world-wide shortage. Therefore, it is important to consider alternative methods of refrigeration. Here, we show that a new type of refrigerant, super-heavy electron metal, YbCo$_2$Zn$_{20}$, can be used for adiabatic demagnetization refrigeration, which does not require 3He gas. A number of advantages includes much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb$_{1-x}$Sc$_x$Co$_2$Zn$_{20}$ by partial Sc substitution with $x\sim$0.19. The substitution induces chemical pressure which drives the materials close to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures enabling final temperatures well below 100 mK. Such performance has up to now been restricted to insulators. Since nearly a century the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. This study opens new possibilities of using itinerant magnetic moments for the cryogen-free refrigeration