The relationship between the critical thinking skills and the academic language proficiency of prospective teachers

We report on the relationships that exist between the critical thinking skills and the academic language proficiency of a group of first-year prospective teachers at a South African university (n = 89). The results revealed the nature of the critical thinking skills as well as the academic language proficiency of the students. Significant correlations between academic language proficiency and making inferences, as well as between academic language proficiency and critical thinking as a general competency, were noted. The article concludes with recommendations on how to enhance critical thinking and language proficiency in the teacher-training curriculum.Keywords: critical thinking ability, critical thinking dispositions, critical thinking skills, improving academic language proficiency, improving critical thinking, language proficiency, outcomes for teacher training, teacher training, teacher training curriculu

Cyclische Diazastannylene. - XI : Ringe und Käfige mit Dimethylbis(methylamido)silan-Liganden am zweiwertigen Zinn

SnCl2 und (LiNMe)2SiMe2 (Me = CH3) reagieren unter Abspaltung von LiCl zu dem molekularen Polycyclus (Me2Si)3(NMe)5Sn2 (I) und zu polymerem (SnNMe)n (II). I kann auch durch Einwirkung von Dimethylbis(methylamino)-silan auf das stannylen Me2Si(NCMe3)2Sn dargestellt werden, wobei weiterhin der Käfig (Me2Si)(NMe)5Sn4 (III) entsteht, wenn ohne Lösungsmittel gearbeitet wird. Auf Grund von 1H-NMR-Spectren und einer Röntgenstrukturanalyse ergeben sich für I und III folgende Strukturen: das Molekülgerüst von I besteht aus einem Sn2N2-Vierring, der in 1,3-Position die Atomsequenz ---Si---N---Si--- und in 2,4-Position ---N—Si---N--- als Brücken trägt; III hat die Structur eines "Basketans\u27;: vier tetraedrisch ausgerichtete Zinnatome und vier Stickstoffatome bilden einen Würfel, in dessen eine Kante eine MeNSiMe2-Einheit eingeschoben ist. Die NMR-Spectren zeigen an, dass in III bei Zimmertemperatur in organischen Lösungsmitteln Bindungsfluktuationen auftreten

High-performance generalized tensor operations: A compiler-oriented approach

The efficiency of tensor contraction is of great importance. Compilers cannot optimize it well enough to come close to the performance of expert-tuned implementations. All existing approaches that provide competitive performance require optimized external code. We introduce a compiler optimization that reaches the performance of optimized BLAS libraries without the need for an external implementation or automatic tuning. Our approach provides competitive performance across hardware architectures and can be generalized to deliver the same benefits for algebraic path problems. By making fast linear algebra kernels available to everyone, we expect productivity increases when optimized libraries are not available. © 2018 Association for Computing Machinery

Kerncraft: A Tool for Analytic Performance Modeling of Loop Kernels

Achieving optimal program performance requires deep insight into the interaction between hardware and software. For software developers without an in-depth background in computer architecture, understanding and fully utilizing modern architectures is close to impossible. Analytic loop performance modeling is a useful way to understand the relevant bottlenecks of code execution based on simple machine models. The Roofline Model and the Execution-Cache-Memory (ECM) model are proven approaches to performance modeling of loop nests. In comparison to the Roofline model, the ECM model can also describes the single-core performance and saturation behavior on a multicore chip. We give an introduction to the Roofline and ECM models, and to stencil performance modeling using layer conditions (LC). We then present Kerncraft, a tool that can automatically construct Roofline and ECM models for loop nests by performing the required code, data transfer, and LC analysis. The layer condition analysis allows to predict optimal spatial blocking factors for loop nests. Together with the models it enables an ab-initio estimate of the potential benefits of loop blocking optimizations and of useful block sizes. In cases where LC analysis is not easily possible, Kerncraft supports a cache simulator as a fallback option. Using a 25-point long-range stencil we demonstrate the usefulness and predictive power of the Kerncraft tool.Comment: 22 pages, 5 figure

Packaging of a high-speed optical modulator using flip chip interconnects

Optical modulators using lithium niobate (LiNbO3) have become the industry standard for high-speed data transmission and RF photonic links. Packaging is a determining factor in maintaining low cost and high-performance. This paper investigates the application of flip chip technology to optical modulator packaging. Experimental results show that rugged flip chip bonds can be realized with minimal impact on the modulator electrical performance

Isomorphisms of algebras of Colombeau generalized functions

We show that for smooth manifolds X and Y, any isomorphism between the special algebra of Colombeau generalized functions on X, resp. Y is given by composition with a unique Colombeau generalized function from Y to X. We also identify the multiplicative linear functionals from the special algebra of Colombeau generalized functions on X to the ring of Colombeau generalized numbers. Up to multiplication with an idempotent generalized number, they are given by an evaluation map at a compactly supported generalized point on X.Comment: 10 page

Regularity properties of distributions through sequences of functions

We give necessary and sufficient criteria for a distribution to be smooth or uniformly H\"{o}lder continuous in terms of approximation sequences by smooth functions; in particular, in terms of those arising as regularizations $(T\ast\phi_{n})$.Comment: 10 page

Interferon-γ acutely augments inhibition of neocortical layer 5 pyramidal neurons

BACKGROUND: Interferon-γ (IFN-γ, a type II IFN) is present in the central nervous system (CNS) under various conditions. Evidence is emerging that, in addition to its immunological role, IFN-γ modulates neuronal morphology, function, and development in several brain regions. Previously, we have shown that raising levels of IFN-β (a type I IFN) lead to increased neuronal excitability of neocortical layer 5 pyramidal neurons. Because of shared non-canonical signaling pathways of both cytokines, we hypothesized a similar neocortical role of acutely applied IFN-γ. METHODS: We used semi-quantitative RT-PCR, immunoblotting, and immunohistochemistry to analyze neuronal expression of IFN-γ receptors and performed whole-cell patch-clamp recordings in layer 5 pyramidal neurons to investigate sub- and suprathreshold excitability, properties of hyperpolarization-activated cyclic nucleotide-gated current (Ih), and inhibitory neurotransmission under the influence of acutely applied IFN-γ. RESULTS: We show that IFN-γ receptors are present in the membrane of rat's neocortical layer 5 pyramidal neurons. As expected from this and the putative overlap in IFN type I and II alternative signaling pathways, IFN-γ diminished Ih, mirroring the effect of type I IFNs, suggesting a likewise activation of protein kinase C (PKC). In contrast, IFN-γ did neither alter subthreshold nor suprathreshold neuronal excitability, pointing to augmented inhibitory transmission by IFN-γ. Indeed, IFN-γ increased electrically evoked inhibitory postsynaptic currents (IPSCs) on neocortical layer 5 pyramidal neurons. Furthermore, amplitudes of spontaneous IPSCs and miniature IPSCs were elevated by IFN-γ, whereas their frequency remained unchanged. CONCLUSIONS: The expression of IFN-γ receptors on layer 5 neocortical pyramidal neurons together with the acute augmentation of inhibition in the neocortex by direct application of IFN-γ highlights an additional interaction between the CNS and immune system. Our results strengthen our understanding of the role of IFN-γ in neocortical neurotransmission and emphasize its impact beyond its immunological properties, particularly in the pathogenesis of neuropsychiatric disorders

On the completeness of impulsive gravitational wave space-times

We consider a class of impulsive gravitational wave space-times, which generalize impulsive pp-waves. They are of the form $M=N\times\mathbb{R}^2_1$, where $(N,h)$ is a Riemannian manifold of arbitrary dimension and $M$ carries the line element $ds^2=dh^2+ 2dudv+f(x)\delta(u)du^2$ with $dh^2$ the line element of $N$ and $\delta$ the Dirac measure. We prove a completeness result for such space-times $M$ with complete Riemannian part $N$.Comment: 13 pages, minor changes suggested by the referee

On the Geroch-Traschen class of metrics

We compare two approaches to semi-Riemannian metrics of low regularity. The maximally 'reasonable' distributional setting of Geroch and Traschen is shown to be consistently contained in the more general setting of nonlinear distributional geometry in the sense of Colombea