Extension to Multiple Species of a Two-Equation Turbulence Model for High Speed Flows

The Wilcox (2006) k-co turbulence model has been extended to multiple species and implemented in a CFD code for high speed flows using the Steger-Warming flux-vector splitting scheme. The model was chosen because compressibility corrections are not required, nor are viscous damping factors or wall functions to produce the law of the wall, and it has previously been validated for approximately one hundred test cases ranging from incompressible to hypersonic flow regimes. Initial validation cases using first-order accuracy have been performed, including a Mach 2.5 flow past a backward-facing step and a Mach 2.85 flow into a 24° compression corner. For the backward-facing step simulation, the surface pressure has a maximum error of 63% in the separation region, less than 5% error after the flow reattaches, and an RMS error of 17.2%, all of which are less than those of Wind-US and Cobalt. For the compression corner case, the surface pressure has a maximum error of 27% in the separation region, roughly 5% error downstream of separation, and an RMS error of 7.76%

A flexible software architecture concept for the creation of accessible PDF documents

This paper presents a flexible software architecture concept that allows the automatic generation of fully accessible PDF documents originating from various authoring tools such as Adobe InDesign or Microsoft Word. The architecture can be extended to include any authoring tools capable of creating PDF documents. For each authoring tool, a software accessibility plug-in must be implemented which analyzes the logical structure of the document and creates an XML representation of it. This XML file is used in combination with an untagged non-accessible PDF to create an accessible PDF version of the document. The implemented accessibility plug-in prototype allows authors of documents to check for accessibility issues while creating their documents and add the additional semantic information needed to generate a fully accessible PDF document

DNA Methylation Analysis Validates Organoids as a Viable Model for Studying Human Intestinal Aging.

Background & aimsThe epithelia of the intestine and colon turn over rapidly and are maintained by adult stem cells at the base of crypts. Although the small intestine and colon have distinct, well-characterized physiological functions, it remains unclear if there are fundamental regional differences in stem cell behavior or region-dependent degenerative changes during aging. Mesenchyme-free organoids provide useful tools for investigating intestinal stem cell biology in vitro and have started to be used for investigating age-related changes in stem cell function. However, it is unknown whether organoids maintain hallmarks of age in the absence of an aging niche. We tested whether stem cell-enriched organoids preserved the DNA methylation-based aging profiles associated with the tissues and crypts from which they were derived.MethodsTo address this, we used standard human methylation arrays and the human epigenetic clock as a biomarker of age to analyze in vitro-derived, 3-dimensional, stem cell-enriched intestinal organoids.ResultsWe found that human stem cell-enriched organoids maintained segmental differences in methylation patterns and that age, as measured by the epigenetic clock, also was maintained in vitro. Surprisingly, we found that stem cell-enriched organoids derived from the small intestine showed striking epigenetic age reduction relative to organoids derived from colon.ConclusionsOur data validate the use of organoids as a model for studying human intestinal aging and introduce methods that can be used when modeling aging or age-onset diseases in vitro

Accelerated epigenetic aging in Werner syndrome.

Individuals suffering from Werner syndrome (WS) exhibit many clinical signs of accelerated aging. While the underlying constitutional mutation leads to accelerated rates of DNA damage, it is not yet known whether WS is also associated with an increased epigenetic age according to a DNA methylation based biomarker of aging (the "Epigenetic Clock"). Using whole blood methylation data from 18 WS cases and 18 age matched controls, we find that WS is associated with increased extrinsic epigenetic age acceleration (p=0.0072) and intrinsic epigenetic age acceleration (p=0.04), the latter of which is independent of age-related changes in the composition of peripheral blood cells. A multivariate model analysis reveals that WS is associated with an increase in DNA methylation age (on average 6.4 years, p=0.011) even after adjusting for chronological age, gender, and blood cell counts. Further, WS might be associated with a reduction in naïve CD8+ T cells (p=0.025) according to imputed measures of blood cell counts. Overall, this study shows that WS is associated with an increased epigenetic age of blood cells which is independent of changes in blood cell composition. The extent to which this alteration is a cause or effect of WS disease phenotypes remains unknown

Biochemistry of Cone Snail toxin activation

posterCone snails use venom to capture prey for food and for defense against predators. The venom is composed of over 100 active peptides that target specific receptors in the nervous system. Several of these peptides have the potential to become medicine for treatment of pain, depression, seizures, and neurological disorders such as Alzheimer 019s disease and MS. In our efforts to understand how cone snails make toxins, we want to purify the Astacin-like protease thought to execute the final steps in toxin activation. Initial trials indicated that purification from bacteria expressing the protease would be challenging. We applied a sparse matrix search to find buffer conditions (pH, salt, metal ions, additives) that maximized yield of soluble Astacin-like protease

Psychological skills training and a mindfulness-based intervention to enhance functional athletic performance: design of a randomized controlled trial using ambulatory assessment

Background: Struggling to deliver performance in competitions is one of the main reasons why athletes seek the advice of sport psychologists. Psychologists apply a variety of intervention techniques, many of which are not evidence-based. Evidence-based techniques promote quality management and could help athletes, for example, to increase and maintain functional athletic behavior in competitions/games (i.e., being focused on task relevant cues and executing movements and actions in high quality). However, well-designed trials investigating the effectiveness of sport psychological interventions for performance enhancement are scarce. The planed study is founded by the Swiss National Science Foundation and examines the effectiveness of two interventions with elite and sub-elite athletes. A psychological skills training (PST) and a mindfulness-based intervention (MI), administered as group-program, will be compared to a waiting-list control group concerning how they enhance functional athletic behavior - which is a prerequisite for optimal performance. Furthermore, we will investigate underlying mechanisms (mediators) and moderators (e.g., task difficulty, individual characteristics, intervention-expectancy and intervention-integrity). Methods/design: The presented trial uses a randomized controlled design with three groups, comparing PST, MI and a waiting list control condition. Both group interventions will last 5 weeks, consist of four 2 h sessions and will be administered by a trained sport psychologist. Primary outcome is functional athletic behavior assessed using ambulatory assessment in a competition/game. As secondary outcomes competition anxiety, cognitive interference and negative outcome expectations will be assessed. Assessments are held at pre- and post-intervention as well as at 2 months follow up. The study has been approved by the ethical committee of the Swiss Federal Institute of Sport. Discussion: Both PST and MI are expected to help improve functional behavior in athletes. By examining potential mechanisms of change and moderators of outcome we will not only be able to answer the question whether the interventions work, but also how, under what conditions, and for whom. This study may also fill a gap in sport psychology research, considering the current lack of randomized controlled trials. In the future, researchers could use the presented study protocol as template to investigate similar topics in sport psychology

Mindfulness Promotes the Ability to Deliver Performance in Highly Demanding Situations

Trait mindfulness helps people handle distress and improves their satisfaction with life. The aim of the present paper is to examine whether trait mindfulness also promotes positive functioning (i.e., performance) in highly demanding situations, such as in elite sports. Mindfulness has been shown to improve athletes’ ability to perform well, i.e., to increase their performance-delivery. However, researchers are still speculating about the underlying mechanism. The present research examines whether trait mindfulness enhances the ability of elite athletes to trigger performance in demanding situations by generally reducing competition anxiety and diminishing its negative impact when it occurs. Participants were 133 elite athletes from 23 different sports. They completed measures of trait mindfulness, competition anxiety, and performance-delivery. Mediation, moderation, and moderated-mediation effects of mindfulness and competition anxiety on performance-delivery were tested. Our findings indicate that trait mindfulness is related to fewer performance worries and prevents the remaining worries from influencing athletes’ behavior, thereby helping them to perform better. Implications and directions for further research are discussed. Apart from benefits for psychological health, instructing people to become more mindful might be a promising approach to help them optimize their performance in demanding situations

Effects of Gamma Ray Bursts in Earth Biosphere

We continue former work on the modeling of potential effects of Gamma Ray Bursts on Phanerozoic Earth. We focus on global biospheric effects of ozone depletion and show a first modeling of the spectral reduction of light by NO2 formed in the stratosphere. We also illustrate the current complexities involved in the prediction of how terrestrial ecosystems would respond to this kind of burst. We conclude that more biological field and laboratory data are needed to reach even moderate accuracy in this modelingComment: Accepted for publication in Astrophysics & Space Scienc