2,204 research outputs found
Measuring cognitive load management in a traditional martial arts training model
A training method utilized in a few martial arts was found to agree strongly with current cognitive psychology theory. Further study extracted a procedural model for learning a complex set of whole-body, dyadic motor skills involving high-speed, interactive, continuous situation assessment and decision making. A broader literature survey found relevance in several fields of research, supporting the definition of four performance dimensions in the activity. Data collected from one experienced student partnering with each of ten students of various experience levels was analyzed on these four dimensions. These dimensions were found sufficient to show both individual differences and changes across an instructional intervention. Strong correlations found under linear regression were supportive of anecdotal evidence from the model??s long empirical history in training. Data provided evidence of a self-organizing dynamic emerging from the interaction of a dyad participating in this activity, and of individual differences in cognitive resource management dynamically setting allocation priorities among specific aspects of a complex motor/cognitive activity. Highly individual responses demonstrate a mechanism for insight into students that are difficult to read. Numerous comparisons and contrasts show interactivity of performance dimensions. Impact is foreseen for research, training and testing in motor learning fields, as well as situation awareness, decision making and military tactical training. Further research is recommended to replicate these findings, test hypotheses derived from them, and to extend testing of the drill-network model into other fields of learning
Influence of modulus‐to‐hardness ratio and harmonic parameters on continuous stiffness measurement during nanoindentation
Dynamic nanoindentation is a popular method for continuously probing the mechanical properties of a sample as a function of depth. Its operation principle and main applications will be reviewed at first. Then, it will be shown that special caution should be exercised when testing materials with high modulus-to-hardness ratios (E/H) at fast loading rates, as the choice of harmonic parameters can result in a significant underestimation of the contact stiffness and hence the elastic modulus.
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Wave nucleation rate in excitable systems in the low noise limit
Motivated by recent experiments on intracellular calcium dynamics, we study
the general issue of fluctuation-induced nucleation of waves in excitable
media. We utilize a stochastic Fitzhugh-Nagumo model for this study, a
spatially-extended non-potential pair of equations driven by thermal (i.e.
white) noise. The nucleation rate is determined by finding the most probable
escape path via minimization of an action related to the deviation of the
fields from their deterministic trajectories. Our results pave the way both for
studies of more realistic models of calcium dynamics as well as of nucleation
phenomena in other non-equilibrium pattern-forming processes
Rapid identification of Burkholderia mallei and Burkholderia pseudomallei by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typing
BACKGROUND: Burkholderia (B.) pseudomallei and B. mallei are genetically closely related species. B. pseudomallei causes melioidosis in humans and animals, whereas B. mallei is the causative agent of glanders in equines and rarely also in humans. Both agents have been classified by the CDC as priority category B biological agents. Rapid identification is crucial, because both agents are intrinsically resistant to many antibiotics. Matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-TOF MS) has the potential of rapid and reliable identification of pathogens, but is limited by the availability of a database containing validated reference spectra. The aim of this study was to evaluate the use of MALDI-TOF MS for the rapid and reliable identification and differentiation of B. pseudomallei and B. mallei and to build up a reliable reference database for both organisms. RESULTS: A collection of ten B. pseudomallei and seventeen B. mallei strains was used to generate a library of reference spectra. Samples of both species could be identified by MALDI-TOF MS, if a dedicated subset of the reference spectra library was used. In comparison with samples representing B. mallei, higher genetic diversity among B. pseudomallei was reflected in the higher average Eucledian distances between the mass spectra and a broader range of identification score values obtained with commercial software for the identification of microorganisms. The type strain of B. pseudomallei (ATCC 23343) was isolated decades ago and is outstanding in the spectrum-based dendrograms probably due to massive methylations as indicated by two intensive series of mass increments of 14 Da specifically and reproducibly found in the spectra of this strain. CONCLUSIONS: Handling of pathogens under BSL 3 conditions is dangerous and cumbersome but can be minimized by inactivation of bacteria with ethanol, subsequent protein extraction under BSL 1 conditions and MALDI-TOF MS analysis being faster than nucleic amplification methods. Our spectra demonstrated a higher homogeneity in B. mallei than in B. pseudomallei isolates. As expected for closely related species, the identification process with MALDI Biotyper software (Bruker Daltonik GmbH, Bremen, Germany) requires the careful selection of spectra from reference strains. When a dedicated reference set is used and spectra of high quality are acquired, it is possible to distinguish both species unambiguously. The need for a careful curation of reference spectra databases is stressed
Physiology and Pharmacology Episcleral Venous Pressure and IOP Responses to Central Electrical Stimulation in the Rat
PURPOSE. Histological evidence suggests a role for the central nervous system in controlling episcleral venous pressure (EVP). Based on prior studies that identified candidate regions in the brain stem, the present study assessed the effect of electrical stimulation at the location of the superior salivatory nucleus (SSN) on EVP in rats. METHODS. Male Sprague-Dawley rats (n ¼ 11) were anesthetized using pentobarbital sodium (50 mg/kg intraperitoneally initially, supplemented intravenously [IV] as needed) and paralyzed with gallamine triethiodide (1 mg/kg, IV). The animals were artificially ventilated and the femoral artery and vein were cannulated for blood pressure measurement and drug administration. Carotid blood flow was measured with an ultrasound flow probe and heart rate with a cardiotachometer. IOP was measured through a cannula in the vitreous compartment and EVP was measured through a micropipette in episcleral veins using the servonull technique. After a craniotomy was performed, a unipolar stainless steel electrode was inserted into the brainstem at the coordinates of the SSN using a stereotactic instrument. Stimulations were performed at 20Hz, 9 lA, 1 ms pulse duration, and 200 pulses. RESULTS. Stimulation at the SSN coordinates increased IOP from 10.6 6 0.4 to 11.8 6 0.6 mm Hg (P < 0.01) and EVP from 7.8 6 1.3 to 10.7 6 1.1 mm Hg (P < 0.01). Mean arterial pressure, carotid blood flow, and heart rate remained unaltered. CONCLUSIONS. The present study indicates that the SSN may participate in regulating EVP. Keywords: episcleral venous pressure, superior salivatory nucleus, stimulation, IOP S teady-state IOP can be described by the Goldmann equation as the relationship between aqueous flow, uveoscleral outflow, outflow facility, and episcleral venous pressure (EVP). 1,2 EVP is the pressure that has to be overcome for fluid to leave the eye via the trabecular outflow pathway and, in humans under normal conditions, EVP accounts for roughly 60% of IOP. Despite its importance for IOP homeostasis, the physiology of the episcleral venous pressure is poorly understood. The current de facto standard for measuring EVP is the venomanometer described by Zeimer et al. 12 Recently, a study by Samuels et al. The brainstem, however, appears to be the first relay station for nerves supplying the eye, and, thus, the nuclei there are likely to be more specialized than higher-order centers in the diencephalon. METHODS The study was approved by the institutional animal care and use committee of the University of Texas Health Science Center at San Antonio and conducted in accordance with the ARVO guidelines for animal use in vision research. All animals were euthanized with an anesthetic overdose at the end of the experiment without regaining consciousness. Animal Preparation Male Sprague Dawley rats (n ¼ 11, 305.4 6 8.6 g) were anesthetized using pentobarbital sodium (Sigma-Aldrich, 50 mg/kg intraperitoneally, supplemented intravenously as needed). A tracheotomy was performed and the animal was respire
SchussenAktivplus: reduction of micropollutants and of potentially pathogenic bacteria for further water quality improvement of the river Schussen, a tributary of Lake Constance, Germany
The project focuses on the efficiency of combined technologies to reduce the release of micropollutants and bacteria into surface waters via sewage treatment plants of different size and via stormwater overflow basins of different types. As a model river in a highly populated catchment area, the river Schussen and, as a control, the river Argen, two tributaries of Lake Constance, Southern Germany, are under investigation in this project. The efficiency of the different cleaning technologies is monitored by a wide range of exposure and effect analyses including chemical and microbiological techniques as well as effect studies ranging from molecules to communities
Evaluating Depressive Symptoms in Schizophrenia: A Psychometric Comparison of the Calgary Depression Scale for Schizophrenia and the Hamilton Depression Rating Scale
Background: The aim of this study was to compare two measures of depression in patients with schizophrenia and schizophrenia spectrum disorder, including patients with delusional and schizoaffective disorder, to conclude implications for their application. Sampling and Methods: A total of 278 patients were assessed using the Calgary Depression Scale for Schizophrenia (CDSS) and the Hamilton Depression Rating Scale (HAMD-17). The Positive and Negative Syndrome Scale (PANSS) was also applied. At admission and discharge, a principal component analysis was performed with each depression scale. The two depression rating scales were furthermore compared using correlation and regression analyses. Results: Three factors were revealed for the CDSS and HAMD-17 factor component analysis. A very similar item loading was found for the CDSS at admission and discharge, whereas results of the loadings of the HAMD-17 items were less stable. The first two factors of the CDSS revealed correlations with positive, negative and general psychopathology. In contrast, multiple significant correlations were found for the HAMD-17 factors and the PANSS sub-scores. Multiple regression analyses demonstrated that the HAMD-17 accounted more for the positive and negative symptom domains than the CDSS. Conclusions:The present results suggest that compared to the HAMD-17, the CDSS is a more specific instrument to measure depressive symptoms in schizophrenia and schizophrenia spectrum disorder, especially in acutely ill patients. Copyright (c) 2012 S. Karger AG, Base
The C-terminal region of Net1 is an activator of RNA polymerase I transcription with conserved features from yeast to human
RNA polymerase I (Pol I) synthesizes ribosomal RNA (rRNA) in all eukaryotes, accounting for the major part of transcriptional activity in proliferating cells. Although basal Pol I transcription factors have been characterized in diverse organisms, the molecular basis of the robust rRNA production in vivo remains largely unknown. In S. cerevisiae, the multifunctional Net1 protein was reported to stimulate Pol I transcription. We found that the Pol I-stimulating function can be attributed to the very C-terminal region (CTR) of Net1. The CTR was required for normal cell growth and Pol I recruitment to rRNA genes in vivo and sufficient to promote Pol I transcription in vitro. Similarity with the acidic tail region of mammalian Pol I transcription factor UBF, which could partly functionally substitute for the CTR, suggests conserved roles for CTR-like domains in Pol I transcription from yeast to human. Author summary The production of ribosomes, cellular factories of protein synthesis, is an essential process driving proliferation and cell growth. Ribosome biogenesis is controlled at the level of synthesis of its components, ribosomal proteins and ribosomal RNA. In eukaryotes, RNA polymerase I is dedicated to transcribe the ribosomal RNA. RNA polymerase I has been identified as a potential target for cell proliferation inhibition. Here we describe the C-terminal region of Net1 as an activator of RNA polymerase I transcription in baker's yeast. In the absence of this activator RNA polymerase I transcription is downregulated and cell proliferation is strongly impaired. Strikingly, this activator might be conserved in human cells, which points to a general mechanism. Our discovery will help to gain a better understanding of the molecular basis of ribosomal RNA synthesis and may have implications in developing strategies to control cellular growth
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