Structure of Anxiety and Depression in Urban Youth: An Examination of the Tripartite Model.

In this study, the authors examined the validity of the tripartite model of anxiety and depression (L. A. Clark & D. Watson, 1991) in a community epidemiological sample of 467 urban African American youth. Participants completed the Baltimore How I Feel (N. S. Ialongo, S. G. Kellam, & J. Poduska, 1999), a measure of anxiety and depressive symptoms, in Grades 6 and 9. Confirmatory factor analyses indicated that a 3-factor model representing the tripartite model fit the data well and better than competing models. Longitudinal confirmatory factor analysis revealed configural invariance of the tripartite factor structure. However, a predicted divergence among dimensions over time was not evidenced. High correlations among the tripartite dimensions suggest that anxiety and mood symptoms may not differentiate in urban youth. Results are discussed in terms of the ethnicity and urban context of this community sample. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Subclinical Depression and Aging on Generative Reasoning About Linear Orders: Same or Different Processing Limitations?

The performance of older adults and depressed people on linear order reasoning is hypothesized to be best explained by different theoretical models. Whereas depressed younger adults are found to be impaired in generative inference making, older adults are well capable of making such inferences but exhibit problems with working memory (Experiments 1 and 2). Restriction of the available study time impairs reasoning by nondepressed control participants and. as such, proves to be a good model of older adults' but not depressed participants' limitations (Experiment 3). These results are replicated comparing depressed and older participants with a control group in the same study, providing increased power and linking the results to additional control measures of processing speed and working memory (Experiment 4). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Response-Discrimination Account of the Simon Effect.

Simon effects might partly reflect stimulus-triggered response activation. According to the response-discrimination hypothesis, however, stimulus-triggered response activation shows up in Simon effects only when stimulus locations match the top-down selected spatial codes used to discriminate between alternative responses. Five experiments support this hypothesis. In Experiment 1, spatial codes of each response differed by horizontal and vertical axis position, yet one axis discriminated between alternative responses, whereas the other did not. Simon effects resulted for targets on discriminating axes only. In Experiment 2, both spatial axes discriminated between responses, and targets on both axes produced Simon effects. In Experiment 3, Simon effects resulted for a spatial choice-reaction task but not for a go/no-go task. Even in the go/no-go task, a Simon effect was restored when a two-choice reaction task preceded the go/no-go task (Experiment 4) or when participants initiated trials with responses spatially discriminated from the go response (Experiment 5). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In-vivo confocal scanning laser microscopy of the cerebral microcirculation

Confocal scanning laser microscopy (CSLM) was used to study the microcirculation of the brain neocortex in anaesthetized rats. After removal of the dura mater, implantation of a closed cranial window, and intravenous injection of fluorescein, three-dimensional reconstructions of cortical capillaries were performed down to a depth of 250 μm below the pial surface. Using a one-dimensional approach (single line scanning), erythrocyte (negative contrast in fluorescently labelled plasma) and leucocyte (labelled with rhodamine 6 G) velocity and supply rate in cortical capillaries were measured. The effect of CO₂-inhalation on capillary blood flow dynamics was studied. Capillaries were imaged continuously for up to 1 h without changes in flow or fluorescence pattern. However, by increasing the laser power 10–100-fold, aggregate formation was induced and capillaries were occluded, possibly due to damage to vascular endothelium. We conclude that CSLM can be used to study morphological and dynamic aspects of fluorescently labelled subsurface structures in organs of experimental animals.     

The Significance of Epithelial-to-Mesenchymal Transition for Circulating Tumor Cells

Epithelial to mesenchymal transition (EMT) is a process involved in embryonic development, but it also plays a role in remote metastasis formation in tumor diseases. During this process cells lose their epithelial features and adopt characteristics of mesenchymal cells. Thereby single tumor cells, which dissolve from the primary tumor, are enabled to invade the blood vessels and travel throughout the body as so called “circulating tumor cells” (CTCs). After leaving the blood stream the reverse process of EMT, the mesenchymal to epithelial transition (MET) helps the cells to seed in different tissues, thereby generating the bud of metastasis formation. As metastasis is the main reason for tumor-associated death, CTCs and the EMT process are in the focus of research in recent years. This review summarizes what was already found out about the molecular mechanisms driving EMT, the consequences of EMT for tumor cell detection, and suitable markers for the detection of CTCs which underwent EMT. The research work done in this field could open new roads towards combating cancer.     

Reconciling fault-tolerant distributed computing and systems-on-chip

Classic distributed computing abstractions do not match well the reality of digital logic gates, which are the elementary building blocks of Systems-on-Chip (SoCs) and other Very Large Scale Integrated (VLSI) circuits: Massively concurrent, continuous computations undermine the concept of sequential processes executing sequences of atomic zero-time computing steps, and very limited computational resources at gate-level make even simple operations prohibitively costly. In this paper, we introduce a modeling and analysis framework based on continuous computations and zero-bit message channels, and employ this framework for the correctness & performance analysis of a distributed fault-tolerant clocking approach for Systems-on-Chip (SoCs). Starting out from a “classic” distributed Byzantine fault-tolerant tick generation algorithm, we show how to adapt it for direct implementation in clockless digital logic, and rigorously prove its correctness and derive analytic expressions for worst case performance metrics like synchronization precision and clock frequency. Rather than on absolute delay values, both the algorithm’s correctness and the achievable synchronization precision depend solely on the ratio of certain path delays. Since these ratios can be mapped directly to placement & routing constraints, there is typically no need for changing the algorithm when migrating to a faster implementation technology and/or when using a slightly different layout in an SoC.