WorldWideScience

Sample records for activity current hypotheses

  1. Use of hypotheses for analysis of variance Models: Challenging the current practice

    NARCIS (Netherlands)

    van Wesel, F.; Boeije, H.R.; Hoijtink, H

    2013-01-01

    In social science research, hypotheses about group means are commonly tested using analysis of variance. While deemed to be formulated as specifically as possible to test social science theory, they are often defined in general terms. In this article we use two studies to explore the current

  2. Urinary plasmin activates collecting duct ENaC current in preeclampsia

    DEFF Research Database (Denmark)

    Buhl, KB; Friis, Ulla Glenert; Svenningsen, Per

    2012-01-01

    In nephrotic syndrome, plasminogen is aberrantly filtered from plasma to the urinary space and activated along the tubular system. In vitro, plasmin increases ENaC current by proteolytic cleavage of the γ-subunit. It was hypothesized that preeclampsia is associated with plasmin-dependent ability...

  3. Global changes of climate through human activities. New clues and hypotheses

    Energy Technology Data Exchange (ETDEWEB)

    Grassl, H

    1988-02-01

    New clues to world-wide changes of climate through human activities have been found or corroborated: Precipitation belts have shifted during the last 30 years; ozone over Antarctica in spring has fallen to its lowest level ever (1956); near-ground ozone in our latitudes has at least doubled in this century. Newly discussed hypotheses are: The oxidation capacity and, consequently, the purification capacity of the atmosphere decreases in the southern hemisphere owing above all to the increase in methane. Increased backscatter of solar radiation through low clouds during periods of turbid air in the atmosphere attenuates the greenhouse effect, the increase in icy clouds through condensation trails of jets flying at high altitudes intensifies the greenhouse effect of the atmosphere. The paper analyses these hypotheses and shows that the distinction between change of climate on the one hand and ecological damage on the other is not justifiable any longer. (orig./HSCH).

  4. HyQue: evaluating hypotheses using Semantic Web technologies

    Directory of Open Access Journals (Sweden)

    Callahan Alison

    2011-05-01

    Full Text Available Abstract Background Key to the success of e-Science is the ability to computationally evaluate expert-composed hypotheses for validity against experimental data. Researchers face the challenge of collecting, evaluating and integrating large amounts of diverse information to compose and evaluate a hypothesis. Confronted with rapidly accumulating data, researchers currently do not have the software tools to undertake the required information integration tasks. Results We present HyQue, a Semantic Web tool for querying scientific knowledge bases with the purpose of evaluating user submitted hypotheses. HyQue features a knowledge model to accommodate diverse hypotheses structured as events and represented using Semantic Web languages (RDF/OWL. Hypothesis validity is evaluated against experimental and literature-sourced evidence through a combination of SPARQL queries and evaluation rules. Inference over OWL ontologies (for type specifications, subclass assertions and parthood relations and retrieval of facts stored as Bio2RDF linked data provide support for a given hypothesis. We evaluate hypotheses of varying levels of detail about the genetic network controlling galactose metabolism in Saccharomyces cerevisiae to demonstrate the feasibility of deploying such semantic computing tools over a growing body of structured knowledge in Bio2RDF. Conclusions HyQue is a query-based hypothesis evaluation system that can currently evaluate hypotheses about the galactose metabolism in S. cerevisiae. Hypotheses as well as the supporting or refuting data are represented in RDF and directly linked to one another allowing scientists to browse from data to hypothesis and vice versa. HyQue hypotheses and data are available at http://semanticscience.org/projects/hyque.

  5. HyQue: evaluating hypotheses using Semantic Web technologies

    Science.gov (United States)

    2011-01-01

    Background Key to the success of e-Science is the ability to computationally evaluate expert-composed hypotheses for validity against experimental data. Researchers face the challenge of collecting, evaluating and integrating large amounts of diverse information to compose and evaluate a hypothesis. Confronted with rapidly accumulating data, researchers currently do not have the software tools to undertake the required information integration tasks. Results We present HyQue, a Semantic Web tool for querying scientific knowledge bases with the purpose of evaluating user submitted hypotheses. HyQue features a knowledge model to accommodate diverse hypotheses structured as events and represented using Semantic Web languages (RDF/OWL). Hypothesis validity is evaluated against experimental and literature-sourced evidence through a combination of SPARQL queries and evaluation rules. Inference over OWL ontologies (for type specifications, subclass assertions and parthood relations) and retrieval of facts stored as Bio2RDF linked data provide support for a given hypothesis. We evaluate hypotheses of varying levels of detail about the genetic network controlling galactose metabolism in Saccharomyces cerevisiae to demonstrate the feasibility of deploying such semantic computing tools over a growing body of structured knowledge in Bio2RDF. Conclusions HyQue is a query-based hypothesis evaluation system that can currently evaluate hypotheses about the galactose metabolism in S. cerevisiae. Hypotheses as well as the supporting or refuting data are represented in RDF and directly linked to one another allowing scientists to browse from data to hypothesis and vice versa. HyQue hypotheses and data are available at http://semanticscience.org/projects/hyque. PMID:21624158

  6. HyQue: evaluating hypotheses using Semantic Web technologies.

    Science.gov (United States)

    Callahan, Alison; Dumontier, Michel; Shah, Nigam H

    2011-05-17

    Key to the success of e-Science is the ability to computationally evaluate expert-composed hypotheses for validity against experimental data. Researchers face the challenge of collecting, evaluating and integrating large amounts of diverse information to compose and evaluate a hypothesis. Confronted with rapidly accumulating data, researchers currently do not have the software tools to undertake the required information integration tasks. We present HyQue, a Semantic Web tool for querying scientific knowledge bases with the purpose of evaluating user submitted hypotheses. HyQue features a knowledge model to accommodate diverse hypotheses structured as events and represented using Semantic Web languages (RDF/OWL). Hypothesis validity is evaluated against experimental and literature-sourced evidence through a combination of SPARQL queries and evaluation rules. Inference over OWL ontologies (for type specifications, subclass assertions and parthood relations) and retrieval of facts stored as Bio2RDF linked data provide support for a given hypothesis. We evaluate hypotheses of varying levels of detail about the genetic network controlling galactose metabolism in Saccharomyces cerevisiae to demonstrate the feasibility of deploying such semantic computing tools over a growing body of structured knowledge in Bio2RDF. HyQue is a query-based hypothesis evaluation system that can currently evaluate hypotheses about the galactose metabolism in S. cerevisiae. Hypotheses as well as the supporting or refuting data are represented in RDF and directly linked to one another allowing scientists to browse from data to hypothesis and vice versa. HyQue hypotheses and data are available at http://semanticscience.org/projects/hyque.

  7. Mechanistic Mathematical Modeling Tests Hypotheses of the Neurovascular Coupling in fMRI.

    Directory of Open Access Journals (Sweden)

    Karin Lundengård

    2016-06-01

    Full Text Available Functional magnetic resonance imaging (fMRI measures brain activity by detecting the blood-oxygen-level dependent (BOLD response to neural activity. The BOLD response depends on the neurovascular coupling, which connects cerebral blood flow, cerebral blood volume, and deoxyhemoglobin level to neuronal activity. The exact mechanisms behind this neurovascular coupling are not yet fully investigated. There are at least three different ways in which these mechanisms are being discussed. Firstly, mathematical models involving the so-called Balloon model describes the relation between oxygen metabolism, cerebral blood volume, and cerebral blood flow. However, the Balloon model does not describe cellular and biochemical mechanisms. Secondly, the metabolic feedback hypothesis, which is based on experimental findings on metabolism associated with brain activation, and thirdly, the neurotransmitter feed-forward hypothesis which describes intracellular pathways leading to vasoactive substance release. Both the metabolic feedback and the neurotransmitter feed-forward hypotheses have been extensively studied, but only experimentally. These two hypotheses have never been implemented as mathematical models. Here we investigate these two hypotheses by mechanistic mathematical modeling using a systems biology approach; these methods have been used in biological research for many years but never been applied to the BOLD response in fMRI. In the current work, model structures describing the metabolic feedback and the neurotransmitter feed-forward hypotheses were applied to measured BOLD responses in the visual cortex of 12 healthy volunteers. Evaluating each hypothesis separately shows that neither hypothesis alone can describe the data in a biologically plausible way. However, by adding metabolism to the neurotransmitter feed-forward model structure, we obtained a new model structure which is able to fit the estimation data and successfully predict new

  8. Preliminary testing of flow-ecology hypotheses developed for the GCP LCC region

    Science.gov (United States)

    Brewer, Shannon K.; Davis, Mary

    2014-01-01

    The Ecological Limits of Hydrological Alteration (ELOHA) framework calls for the development of flow-ecology hypotheses to support protection of the flow regime from ecologically harmful alteration due to human activities. As part of a larger instream flow project for the Gulf Coast Prairie Landscape Conservation Cooperative (GCP LCC), regional flow-ecology hypotheses were developed for fish, mussels, birds, and riparian vegetation (Davis and Brewer 20141). The objective of this study was to assess the usefulness of existing ecological and hydrological data to test these hypotheses or others that may be developed in the future. Several databases related to biological collections and hydrologic data from Oklahoma, Texas, and Louisiana were compiled. State fish-community data from Oklahoma and Louisiana were summarized and paired with existing USGS gage data having at least a 40-year period of record that could be separated into reference and current conditions for comparison. The objective of this study was not to conduct exhaustive analyses of these data, the hypotheses, or analyses interpretation, but rather to use these data to determine if existing data were adequate to statistically test the regional flow-ecology hypotheses. The regional flow-ecology hypotheses were developed for the GCP LCC by a committee chaired by Shannon Brewer and Mary Davis (Davis and Brewer 2014). Existing data were useful for informing the hypotheses and suggest support for some hypotheses, but also highlight the need for additional testing and development as some results contradicted hypotheses. Results presented here suggest existing data are adequate to support some flow-ecology hypotheses; however, lack of sampling effort reported with the fish collections and the need for ecoregion-specific analyses suggest more data would be beneficial to analyses in some ecoregions. Additional fish sampling data from Texas and Louisiana will be available for future analyses and may ameliorate

  9. Testing competing hypotheses about single trial fMRI

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Purushotham, Archana; Kim, Seong-Ge

    2002-01-01

    We use a Bayesian framework to compute probabilities of competing hypotheses about functional activation based on single trial fMRI measurements. Within the framework we obtain a complete probabilistic picture of competing hypotheses, hence control of both type I and type II errors....

  10. Rapid Detection Strategies for the Global Threat of Zika Virus: Current State, New Hypotheses and Limitations

    Directory of Open Access Journals (Sweden)

    Shruti Shukla

    2016-10-01

    Full Text Available The current scenario regarding the widespread Zika virus (ZIKV has resulted in numerous diagnostic studies, specifically in South America and in locations where there is frequent entry of travelers returning from ZIKV-affected areas, including pregnant women with or without clinical symptoms of ZIKV infection. The World Health Organization, WHO, announced that millions of cases of ZIKV are likely to occur in the United States of America in the near future. This situation has created an alarming public health emergency of international concern requiring the detection of this life-threatening viral candidate due to increased cases of newborn microcephaly associated with ZIKV infection. Hence, this review reports possible methods and strategies for the fast and reliable detection of ZIKV with particular emphasis on current updates, knowledge and new hypotheses that might be helpful for medical professionals in poor and developing countries that urgently need to address this problem. In particular, we emphasize liposome-based biosensors. Although these biosensors are currently among the less popular tools for human disease detection, they have become useful tools for the screening and detection of pathogenic bacteria, fungi and viruses because of their versatile advantageous features compared to other sensing devices. This review summarizes the currently available methods employed for the rapid detection of ZIKV and suggests an innovative approach involving the application of a liposome-based hypothesis for the development of new strategies for ZIKV detection and their use as effective biomedicinal tools.

  11. Dental Hypotheses: Seeks to Publish Hypotheses from All Areas of Dentistry

    Directory of Open Access Journals (Sweden)

    Edward F. Rossomando

    2010-07-01

    Full Text Available Starting a new open access journal in a rapid growing scientific panorama is a severe challenge. However, the first issue of dental hypotheses is now history and the even skeptics can appreciate that dental hypotheses is a success - it is a journal of high quality that provides an outlet for publication of articles that encourage readers to question dental paradigms. But dental hypotheses readers might have noticed that the majority of the articles published in the first issue of dental hypotheses concern clinical dentistry. However, dental hypotheses editors recognize that there are many other areas in dentistry that present challenges and that our readers may offer suggestions for their solution. Some of these challenges relate to: dental education; digital dental technology; teledentistry and access to dental care; dental practice issues, such as, dental office design, dental office management, the slow rate of acceptance of innovative technology in the dental office; and issues related to innovation and dental entrepreneurship including intellectual property protection. Nevertheless, the dental profession faces many challenges - in many areas - and with the publication of dental hypotheses our profession has a venue for presentation of possible solutions. If you have developed a hypothesis that might help, please share it with your colleagues. As many have noted, the intellectual power of the global village in which we now live is formidable. The internet has provided the technology to bring us together and dental hypotheses has provided the venue. Please use it. New radical, speculative and non-mainstream scientific ideas are always welcome.

  12. The evolution of parental care in insects: A test of current hypotheses

    Science.gov (United States)

    Gilbert, James D J; Manica, Andrea

    2015-01-01

    Which sex should care for offspring is a fundamental question in evolution. Invertebrates, and insects in particular, show some of the most diverse kinds of parental care of all animals, but to date there has been no broad comparative study of the evolution of parental care in this group. Here, we test existing hypotheses of insect parental care evolution using a literature-compiled phylogeny of over 2000 species. To address substantial uncertainty in the insect phylogeny, we use a brute force approach based on multiple random resolutions of uncertain nodes. The main transitions were between no care (the probable ancestral state) and female care. Male care evolved exclusively from no care, supporting models where mating opportunity costs for caring males are reduced—for example, by caring for multiple broods—but rejecting the “enhanced fecundity” hypothesis that male care is favored because it allows females to avoid care costs. Biparental care largely arose by males joining caring females, and was more labile in Holometabola than in Hemimetabola. Insect care evolution most closely resembled amphibian care in general trajectory. Integrating these findings with the wealth of life history and ecological data in insects will allow testing of a rich vein of existing hypotheses. PMID:25825047

  13. The evolution of parental care in insects: A test of current hypotheses.

    Science.gov (United States)

    Gilbert, James D J; Manica, Andrea

    2015-05-01

    Which sex should care for offspring is a fundamental question in evolution. Invertebrates, and insects in particular, show some of the most diverse kinds of parental care of all animals, but to date there has been no broad comparative study of the evolution of parental care in this group. Here, we test existing hypotheses of insect parental care evolution using a literature-compiled phylogeny of over 2000 species. To address substantial uncertainty in the insect phylogeny, we use a brute force approach based on multiple random resolutions of uncertain nodes. The main transitions were between no care (the probable ancestral state) and female care. Male care evolved exclusively from no care, supporting models where mating opportunity costs for caring males are reduced-for example, by caring for multiple broods-but rejecting the "enhanced fecundity" hypothesis that male care is favored because it allows females to avoid care costs. Biparental care largely arose by males joining caring females, and was more labile in Holometabola than in Hemimetabola. Insect care evolution most closely resembled amphibian care in general trajectory. Integrating these findings with the wealth of life history and ecological data in insects will allow testing of a rich vein of existing hypotheses. © 2015 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

  14. Voltage Dependence of a Neuromodulator-Activated Ionic Current123

    Science.gov (United States)

    2016-01-01

    Abstract The neuromodulatory inward current (IMI) generated by crab Cancer borealis stomatogastric ganglion neurons is an inward current whose voltage dependence has been shown to be crucial in the activation of oscillatory activity of the pyloric network of this system. It has been previously shown that IMI loses its voltage dependence in conditions of low extracellular calcium, but that this effect appears to be regulated by intracellular calmodulin. Voltage dependence is only rarely regulated by intracellular signaling mechanisms. Here we address the hypothesis that the voltage dependence of IMI is mediated by intracellular signaling pathways activated by extracellular calcium. We demonstrate that calmodulin inhibitors and a ryanodine antagonist can reduce IMI voltage dependence in normal Ca2+, but that, in conditions of low Ca2+, calmodulin activators do not restore IMI voltage dependence. Further, we show evidence that CaMKII alters IMI voltage dependence. These results suggest that calmodulin is necessary but not sufficient for IMI voltage dependence. We therefore hypothesize that the Ca2+/calmodulin requirement for IMI voltage dependence is due to an active sensing of extracellular calcium by a GPCR family calcium-sensing receptor (CaSR) and that the reduction in IMI voltage dependence by a calmodulin inhibitor is due to CaSR endocytosis. Supporting this, preincubation with an endocytosis inhibitor prevented W7 (N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride)-induced loss of IMI voltage dependence, and a CaSR antagonist reduced IMI voltage dependence. Additionally, myosin light chain kinase, which is known to act downstream of the CaSR, seems to play a role in regulating IMI voltage dependence. Finally, a Gβγ-subunit inhibitor also affects IMI voltage dependence, in support of the hypothesis that this process is regulated by a G-protein-coupled CaSR. PMID:27257619

  15. ITSSOIN Hypotheses

    NARCIS (Netherlands)

    Anheier, H.K.; Krlev, G.; Preuss, S.; Mildenberger, G.; Bekkers, R.H.F.P.; Brink Lund, A.

    2014-01-01

    This report brings together findings from the first ITSSOIN project working steps to formulate empirically testable hypotheses on the impact of the third sector and social innovation – in particular regarding the role of the third sector in generating social innovation but also with reference to

  16. Testing hypotheses in order

    OpenAIRE

    Paul R. Rosenbaum

    2008-01-01

    In certain circumstances, one wishes to test one hypothesis only if certain other hypotheses have been rejected. This ordering of hypotheses simplifies the task of controlling the probability of rejecting any true hypothesis. In an example from an observational study, a treated group is shown to be further from both of two control groups than the two control groups are from each other. Copyright 2008, Oxford University Press.

  17. The revelation effect: A meta-analytic test of hypotheses.

    Science.gov (United States)

    Aßfalg, André; Bernstein, Daniel M; Hockley, William

    2017-12-01

    Judgments can depend on the activity directly preceding them. An example is the revelation effect whereby participants are more likely to claim that a stimulus is familiar after a preceding task, such as solving an anagram, than without a preceding task. We test conflicting predictions of four revelation-effect hypotheses in a meta-analysis of 26 years of revelation-effect research. The hypotheses' predictions refer to three subject areas: (1) the basis of judgments that are subject to the revelation effect (recollection vs. familiarity vs. fluency), (2) the degree of similarity between the task and test item, and (3) the difficulty of the preceding task. We use a hierarchical multivariate meta-analysis to account for dependent effect sizes and variance in experimental procedures. We test the revelation-effect hypotheses with a model selection procedure, where each model corresponds to a prediction of a revelation-effect hypothesis. We further quantify the amount of evidence for one model compared to another with Bayes factors. The results of this analysis suggest that none of the extant revelation-effect hypotheses can fully account for the data. The general vagueness of revelation-effect hypotheses and the scarcity of data were the major limiting factors in our analyses, emphasizing the need for formalized theories and further research into the puzzling revelation effect.

  18. Explanatory hypotheses formation and the anomalous β spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Gauderis, Tjerk [Centre for Logic and Philosophy of Science, Ghent University (Belgium)

    2013-07-01

    Between 1928 and 1934, a persevering anomaly mystified the physics community: while alpha decay behaved perfectly according to the new quantum mechanics, the energy of electrons emitted in beta decay displayed a broad continuous spectrum. This puzzle invoked a lively debate among the most established physicists at the time. But the curious thing was that they all suggested hypotheses of very different formal types: Rutherford and Chadwick thought of varying internal energies, Bohr suggested to restrict the energy conservation principle, Heisenberg tinkered with a new quantization of space, and Pauli suggested the existence of a new elementary particle - all these hypotheses being radical and highly controversial. In physics, an anomalous experimental result can trigger the formation of formally very different hypotheses. A scientist confronted with such a result has no strict guidelines to help her decide whether she should explain this result by withdrawing or adapting a constraint (e.g. a law) of the current theory, or by presupposing the existence of a hitherto unobserved entity (e.g. a particle) that makes the anomaly fit within that theory. In this talk I aim to gain some insights how scientists make this choice, by examining in the above case study how the choice of the various mentioned physicists depended on their previous experiences and their specific perception of the problem.

  19. Economic and evolutionary hypotheses for cross-population variation in parochialism

    OpenAIRE

    Daniel Jacob Hruschka; Joseph eHenrich

    2013-01-01

    Human populations differ reliably in the degree to which people favor family, friends and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review recent attempts to test them. We also discuss the key methodological challenges in assessing these diverse economic and evolutionary theories...

  20. Using Transcranial tDCS to test cognitive hypotheses

    Directory of Open Access Journals (Sweden)

    Nazbanou Nozari

    2014-04-01

    Full Text Available Transcranial Direct Current Stimulation (tDCS is used increasingly often for testing cognitive hypotheses. It is, however, often ignored that many assumptions regarding how the neural tissue reacts to stimulation have only been verified in the motor domain. Extrapolating these assumptions to the cognitive domain has a set of unique issues which, if ignored, can lead to incorrect interpretations. In this talk I will review a number of common pitfalls in using tDCS for testing a cognitive hypothesis, and discuss some solutions for better-controlled designs. I will address the following issues: 1- Making an incorrect assumption about the nature of the effect: It is often assumed that anodal stimulation has “excitatory” and cathodal stimulation has “inhibitory” effects. Results are then interpreted in light of this assumption. Obviously, if the assumption is incorrect, the interpretation of the results too will be incorrect. I will discuss how the effects of polarity can change as a function of a number of design parameters, and the dangers of making a priori assumptions about the direction of stimulation effects, especially when employing a new design. 2- Choosing an inappropriate montage: By definition, tDCS requires two electrodes, although we are often only interested in stimulating one brain region. Where the second (reference electrode is placed may not be of theoretical interest to us, but it can have serious consequences for our effects of interest. For one thing the path of the direct current changes as a function of where the reference electrode is placed. This affects the density of the current, as well as the regions that undergo stimulation. Moreover, the region directly under the reference electrode is very likely to be affected by stimulation. Therefore, sometimes the changes in behavior may be due to the unanticipated effects at the reference electrode site, as opposed to the hypothesized effects at the target electrode site

  1. Does bipolar pacemaker current activate blood platelets?

    DEFF Research Database (Denmark)

    Gjesdal, Grunde; Hansen, Annebirthe Bo; Brandes, Axel

    2009-01-01

    OBJECTIVE: The aim of this study was to investigate whether bipolar pacemaker current lead can activate blood platelets. The null hypothesis was that 1 minute of electrical stimulation of platelets would not influence their subsequent reactivity to adenosine diphosphate (ADP). BACKGROUND: Both...... platelets and muscle cells contain actin and myosin filaments, and both cells are activated following calcium influx. Muscle cells open their calcium channels and contract when exposed to an electric current. Current through a bipolar pacemaker lead will expose a small volume of blood, including platelets......, to the depolarizing current. Platelet activation may ensue, resulting in aggregation, release reaction, and contraction. In contrast, a unipolar pacemaker system will not depolarize blood, but transmit current directly into the myocardium, and the current afterward passes through other tissues before returning...

  2. Causes of bat fatalities at wind turbines: Hypotheses and predictions

    Science.gov (United States)

    Cryan, P.M.; Barclay, R.M.R.

    2009-01-01

    Thousands of industrial-scale wind turbines are being built across the world each year to meet the growing demand for sustainable energy. Bats of certain species are dying at wind turbines in unprecedented numbers. Species of bats consistently affected by turbines tend to be those that rely on trees as roosts and most migrate long distances. Although considerable progress has been made in recent years toward better understanding the problem, the causes of bat fatalities at turbines remain unclear. In this synthesis, we review hypothesized causes of bat fatalities at turbines. Hypotheses of cause fall into 2 general categoriesproximate and ultimate. Proximate causes explain the direct means by which bats die at turbines and include collision with towers and rotating blades, and barotrauma. Ultimate causes explain why bats come close to turbines and include 3 general types: random collisions, coincidental collisions, and collisions that result from attraction of bats to turbines. The random collision hypothesis posits that interactions between bats and turbines are random events and that fatalities are representative of the bats present at a site. Coincidental hypotheses posit that certain aspects of bat distribution or behavior put them at risk of collision and include aggregation during migration and seasonal increases in flight activity associated with feeding or mating. A surprising number of attraction hypotheses suggest that bats might be attracted to turbines out of curiosity, misperception, or as potential feeding, roosting, flocking, and mating opportunities. Identifying, prioritizing, and testing hypothesized causes of bat collisions with wind turbines are vital steps toward developing practical solutions to the problem. ?? 2009 American Society of Mammalogists.

  3. Evaluation of Extremal Hypotheses as a Criterion to Resolve Channel Indeterminacy

    Science.gov (United States)

    Tranmer, A.

    2012-12-01

    Design criteria for river restoration and sustainable development have significantly advanced in recent decades, yet complete deterministic formulations to address channel form and sinuosity still prove elusive. Many hypotheses have been presented to ascertain the dynamic-equilibrium of a stream at both the cross sectional and reach level. These efforts to better understand the functioning of alluvial systems include regime theory, stability theory, perturbation analysis, threshold theory, reference reach comparison, downstream hydraulic geometry, and extremal hypotheses. The latter of these theories, the extremal hypothesis, is based on optimizing one variable or criterion in the alluvial system in order to find closure to the channel design problem. Currently, there is no method to directly compare the various hypotheses at the system scale, understanding of their sensitivity to the various formulae employed or consensus regarding which hypothesis is most appropriate. This study analyzed the various extremal hypotheses in as close to a pristine environment as exists (a remote part of Patagonia, Chile), in order to assess which hypothesis (or collective hypotheses) is most appropriate for channel design. Extremal hypotheses were applied in the longitudinal direction, under the assumption of a space-for-time substitution, to evaluate the geomorphic trends of a river evolving during deglaciation. The space-for-time model assumes the watershed reaches stable, dynamic-equilibrium in its lower meandering reaches and the point of equilibrium extends upstream through its braiding reaches as the watershed adapts to new climatic and environmental conditions. Extremal hypotheses applied in a downstream fashion are then expected to predict chaotic and oversized channel characteristics in the upstream reaches and trend towards a point of equilibrium (minimum/maximum of tested hypothesis). Initial findings indicate that many hypotheses predict similar geometry and sinuosity

  4. Economic and evolutionary hypotheses for cross-population variation in parochialism.

    Science.gov (United States)

    Hruschka, Daniel J; Henrich, Joseph

    2013-09-11

    Human populations differ reliably in the degree to which people favor family, friends, and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review recent attempts to test them. We also discuss the key methodological challenges in assessing these diverse economic and evolutionary theories for cross-population differences in parochialism.

  5. Predictive hypotheses are ineffectual in resolving complex biochemical systems.

    Science.gov (United States)

    Fry, Michael

    2018-03-20

    Scientific hypotheses may either predict particular unknown facts or accommodate previously-known data. Although affirmed predictions are intuitively more rewarding than accommodations of established facts, opinions divide whether predictive hypotheses are also epistemically superior to accommodation hypotheses. This paper examines the contribution of predictive hypotheses to discoveries of several bio-molecular systems. Having all the necessary elements of the system known beforehand, an abstract predictive hypothesis of semiconservative mode of DNA replication was successfully affirmed. However, in defining the genetic code whose biochemical basis was unclear, hypotheses were only partially effective and supplementary experimentation was required for its conclusive definition. Markedly, hypotheses were entirely inept in predicting workings of complex systems that included unknown elements. Thus, hypotheses did not predict the existence and function of mRNA, the multiple unidentified components of the protein biosynthesis machinery, or the manifold unknown constituents of the ubiquitin-proteasome system of protein breakdown. Consequently, because of their inability to envision unknown entities, predictive hypotheses did not contribute to the elucidation of cation theories remained the sole instrument to explain complex bio-molecular systems, the philosophical question of alleged advantage of predictive over accommodative hypotheses became inconsequential.

  6. Economic and evolutionary hypotheses for cross-population variation in parochialism

    Directory of Open Access Journals (Sweden)

    Daniel Jacob Hruschka

    2013-09-01

    Full Text Available Human populations differ reliably in the degree to which people favor family, friends and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review recent attempts to test them. We also discuss the key methodological challenges in assessing these diverse economic and evolutionary theories for cross-population differences in parochialism.

  7. Quantitative linking hypotheses for infant eye movements.

    Directory of Open Access Journals (Sweden)

    Daniel Yurovsky

    Full Text Available The study of cognitive development hinges, largely, on the analysis of infant looking. But analyses of eye gaze data require the adoption of linking hypotheses: assumptions about the relationship between observed eye movements and underlying cognitive processes. We develop a general framework for constructing, testing, and comparing these hypotheses, and thus for producing new insights into early cognitive development. We first introduce the general framework--applicable to any infant gaze experiment--and then demonstrate its utility by analyzing data from a set of experiments investigating the role of attentional cues in infant learning. The new analysis uncovers significantly more structure in these data, finding evidence of learning that was not found in standard analyses and showing an unexpected relationship between cue use and learning rate. Finally, we discuss general implications for the construction and testing of quantitative linking hypotheses. MATLAB code for sample linking hypotheses can be found on the first author's website.

  8. Pearce element ratios: A paradigm for testing hypotheses

    Science.gov (United States)

    Russell, J. K.; Nicholls, Jim; Stanley, Clifford R.; Pearce, T. H.

    Science moves forward with the development of new ideas that are encapsulated by hypotheses whose aim is to explain the structure of data sets or to expand existing theory. These hypotheses remain conjecture until they have been tested. In fact, Karl Popper advocated that a scientist's job does not finish with the creation of an idea but, rather, begins with the testing of the related hypotheses. In Popper's [1959] advocation it is implicit that there be tools with which we can test our hypotheses. Consequently, the development of rigorous tests for conceptual models plays a major role in maintaining the integrity of scientific endeavor [e.g., Greenwood, 1989].

  9. Drug-Resistant Epilepsy: Multiple Hypotheses, Few Answers

    Directory of Open Access Journals (Sweden)

    Fei Tang

    2017-07-01

    Full Text Available Epilepsy is a common neurological disorder that affects over 70 million people worldwide. Despite the recent introduction of new antiseizure drugs (ASDs, about one-third of patients with epilepsy have seizures refractory to pharmacotherapy. Early identification of patients who will become refractory to ASDs could help direct such patients to appropriate non-pharmacological treatment, but the complexity in the temporal patterns of epilepsy could make such identification difficult. The target hypothesis and transporter hypothesis are the most cited theories trying to explain refractory epilepsy, but neither theory alone fully explains the neurobiological basis of pharmacoresistance. This review summarizes evidence for and against several major theories, including the pharmacokinetic hypothesis, neural network hypothesis, intrinsic severity hypothesis, gene variant hypothesis, target hypothesis, and transporter hypothesis. The discussion is mainly focused on the transporter hypothesis, where clinical and experimental data are discussed on multidrug transporter overexpression, substrate profiles of ASDs, mechanism of transporter upregulation, polymorphisms of transporters, and the use of transporter inhibitors. Finally, future perspectives are presented for the improvement of current hypotheses and the development of treatment strategies as guided by the current understanding of refractory epilepsy.

  10. How doctors generate diagnostic hypotheses: a study of radiological diagnosis with functional magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Marcio Melo

    Full Text Available In medical practice, diagnostic hypotheses are often made by physicians in the first moments of contact with patients; sometimes even before they report their symptoms. We propose that generation of diagnostic hypotheses in this context is the result of cognitive processes subserved by brain mechanisms that are similar to those involved in naming objects or concepts in everyday life.To test this proposal we developed an experimental paradigm with functional magnetic resonance imaging (fMRI using radiological diagnosis as a model. Twenty-five radiologists diagnosed lesions in chest X-ray images and named non-medical targets (animals embedded in chest X-ray images while being scanned in a fMRI session. Images were presented for 1.5 seconds; response times (RTs and the ensuing cortical activations were assessed. The mean response time for diagnosing lesions was 1.33 (SD ±0.14 seconds and 1.23 (SD ±0.13 seconds for naming animals. 72% of the radiologists reported cogitating differential diagnoses during trials (3.5 seconds. The overall pattern of cortical activations was remarkably similar for both types of targets. However, within the neural systems shared by both stimuli, activation was significantly greater in left inferior frontal sulcus and posterior cingulate cortex for lesions relative to animals.Generation of diagnostic hypotheses and differential diagnoses made through the immediate visual recognition of clinical signs can be a fast and automatic process. The co-localization of significant brain activation for lesions and animals suggests that generating diagnostic hypotheses for lesions and naming animals are served by the same neuronal systems. Nevertheless, diagnosing lesions was cognitively more demanding and associated with more activation in higher order cortical areas. These results support the hypothesis that medical diagnoses based on prompt visual recognition of clinical signs and naming in everyday life are supported by similar

  11. An extension of hypotheses regarding rapid-acting, treatment-refractory, and conventional antidepressant activity of dextromethorphan and dextrorphan.

    Science.gov (United States)

    Lauterbach, Edward C

    2012-06-01

    It was previously hypothesized that dextromethorphan (DM) and dextrorphan (DX) may possess antidepressant properties, including rapid and conventional onsets of action and utility in treatment-refractory depression, based on pharmacodynamic similarities to ketamine. These similarities included sigma-1 (σ(1)) agonist and NMDA antagonist properties, calcium channel blockade, muscarinic binding, serotonin transporter (5HTT) inhibition, and μ receptor potentiation. Here, six specific hypotheses are developed in light of additional mechanisms and evidence. Comparable potencies to ketamine for DM and DX are detailed for σ(1) (DX>DM>ketamine), NMDA PCP site (DX>ketamine>DM), and muscarinic (DX>ketamine>DM) receptors, 5HTT (DM>DX≫ketamine), and NMDA antagonist potentiation of μ receptor stimulation (DM>ketamine). Rapid acting antidepressant properties of DM include NMDA high-affinity site, NMDR-2A, and functional NMDR-2B receptor antagonism, σ(1) stimulation, putative mTOR activation (by σ(1) stimulation, μ potentiation, and 5HTT inhibition), putative AMPA receptor trafficking (by mTOR activation, PCP antagonism, σ(1) stimulation, μ potentiation, and 5HTT inhibition), and dendritogenesis, spinogenesis, synaptogenesis, and neuronal survival by NMDA antagonism and σ(1) and mTOR signaling. Those for dextrorphan include NMDA high-affinity site and NMDR-2A antagonism, σ(1) stimulation, putative mTOR activation (by σ(1) stimulation and ß adrenoreceptor stimulation), putative AMPA receptor trafficking (by mTOR activation, PCP antagonism, σ(1) stimulation, ß stimulation, and μ antagonism), and dendritogenesis, spinogenesis, synaptogenesis, and neuronal survival by NMDA antagonism and σ(1) and mTOR signaling. Conventional antidepressant properties for dextromethorphan and dextrorphan include 5HTT and norepinephrine transporter inhibition, σ(1) stimulation, NMDA and PCP antagonism, and possible serotonin 5HT1b/d receptor stimulation. Additional properties for

  12. A survey of etiologic hypotheses among testicular cancer researchers.

    Science.gov (United States)

    Stang, A; Trabert, B; Rusner, C; Poole, C; Almstrup, K; Rajpert-De Meyts, E; McGlynn, K A

    2015-01-01

    Basic research results can provide new ideas and hypotheses to be examined in epidemiological studies. We conducted a survey among testicular cancer researchers on hypotheses concerning the etiology of this malignancy. All researchers on the mailing list of Copenhagen Testis Cancer Workshops and corresponding authors of PubMed-indexed articles identified by the search term 'testicular cancer' and published within 10 years (in total 2750 recipients) were invited to respond to an e-mail-based survey. Participants of the 8th Copenhagen Testis Cancer Workshop in May 2014 were subsequently asked to rate the plausibility of the suggested etiologic hypotheses on a scale of 1 (very implausible) to 10 (very plausible). This report describes the methodology of the survey, the score distributions by individual hypotheses, hypothesis group, and the participants' major research fields, and discuss the hypotheses that scored as most plausible. We also present plans for improving the survey that may be repeated at a next international meeting of experts in testicular cancer. Overall 52 of 99 (53%) registered participants of the 8th Copenhagen Testis Cancer Workshop submitted the plausibility rating form. Fourteen of 27 hypotheses were related to exposures during pregnancy. Hypotheses with the highest mean plausibility ratings were either related to pre-natal exposures or exposures that might have an effect during pregnancy and in post-natal life. The results of the survey may be helpful for triggering more specific etiologic hypotheses that include factors related to endocrine disruption, DNA damage, inflammation, and nutrition during pregnancy. The survey results may stimulate a multidisciplinary discussion about new etiologic hypotheses of testicular cancer. Published 2014. This article is a U. S. Government work and is in the public domain in the USA.

  13. Scientific 'Laws', 'Hypotheses' and 'Theories'

    Indian Academy of Sciences (India)

    verified, the hypothesis changes from the status of a 'mere' hypothesis, and ... a pre-existing law and the body of facts upon which that law is based. Hypotheses .... implicit belief that order objectively exists in nature, and that scientific laws ...

  14. Scientific 'Laws', 'Hypotheses' and 'Theories'

    Indian Academy of Sciences (India)

    theories, defines a hypothesis as "any supposition which we may ... about the origin of the solar system are also hypotheses of this type. They are about the birth of the planets, an event, which has happened, in the past history of our Universe.

  15. Scientific'Laws','Hypotheses' and'Theories'

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 12. Scientific 'Laws', 'Hypotheses' and 'Theories' - How are They Related? J R Lakshmana Rao. General Article Volume 3 Issue 12 December 1998 pp 55-61. Fulltext. Click here to view fulltext PDF. Permanent link:

  16. Testing hypotheses for differences between linear regression lines

    Science.gov (United States)

    Stanley J. Zarnoch

    2009-01-01

    Five hypotheses are identified for testing differences between simple linear regression lines. The distinctions between these hypotheses are based on a priori assumptions and illustrated with full and reduced models. The contrast approach is presented as an easy and complete method for testing for overall differences between the regressions and for making pairwise...

  17. Phonological and conceptual activation in speech comprehension

    NARCIS (Netherlands)

    Norris, D.; Cutler, A.; McQueen, J.M.; Butterfield, S.

    2006-01-01

    We propose that speech comprehension involves the activation of token representations of the phonological forms of current lexical hypotheses, separately from the ongoing construction of a conceptual interpretation of the current utterance. In a series of cross-modal priming experiments,

  18. Independence of long-term contextual memory and short-term perceptual hypotheses: evidence from contextual cueing of interrupted search

    OpenAIRE

    Schlagbauer, B.; Mink, M.; Muller, Hermann J.; Geyer, T.

    2017-01-01

    Observers are able to resume an interrupted search trial faster relative to responding to a new, unseen display. This finding of rapid resumption is attributed to short-term perceptual hypotheses generated on the current look and confirmed upon subsequent looks at the same display. It has been suggested that the contents of perceptual hypotheses are similar to those of other forms of memory acquired long-term through repeated exposure to the same search displays over the course of several tri...

  19. Independence of long-term contextual memory and short-term perceptual hypotheses: Evidence from contextual cueing of interrupted search.

    Science.gov (United States)

    Schlagbauer, Bernhard; Mink, Maurice; Müller, Hermann J; Geyer, Thomas

    2017-02-01

    Observers are able to resume an interrupted search trial faster relative to responding to a new, unseen display. This finding of rapid resumption is attributed to short-term perceptual hypotheses generated on the current look and confirmed upon subsequent looks at the same display. It has been suggested that the contents of perceptual hypotheses are similar to those of other forms of memory acquired long-term through repeated exposure to the same search displays over the course of several trials, that is, the memory supporting "contextual cueing." In three experiments, we investigated the relationship between short-term perceptual hypotheses and long-term contextual memory. The results indicated that long-term, contextual memory of repeated displays neither affected the generation nor the confirmation of short-term perceptual hypotheses for these displays. Furthermore, the analysis of eye movements suggests that long-term memory provides an initial benefit in guiding attention to the target, whereas in subsequent looks guidance is entirely based on short-term perceptual hypotheses. Overall, the results reveal a picture of both long- and short-term memory contributing to reliable performance gains in interrupted search, while exerting their effects in an independent manner.

  20. In silico generation of alternative hypotheses using causal mapping (CMAP.

    Directory of Open Access Journals (Sweden)

    Gabriel E Weinreb

    Full Text Available Previously, we introduced causal mapping (CMAP as an easy to use systems biology tool for studying the behavior of biological processes that occur at the cellular and molecular level. CMAP is a coarse-grained graphical modeling approach in which the system of interest is modeled as an interaction map between functional elements of the system, in a manner similar to portrayals of signaling pathways commonly used by molecular cell biologists. CMAP describes details of the interactions while maintaining the simplicity of other qualitative methods (e.g., Boolean networks.In this paper, we use the CMAP methodology as a tool for generating hypotheses about the mechanisms that regulate molecular and cellular systems. Furthermore, our approach allows competing hypotheses to be ranked according to a fitness index and suggests experimental tests to distinguish competing high fitness hypotheses. To motivate the CMAP as a hypotheses generating tool and demonstrate the methodology, we first apply this protocol to a simple test-case of a three-element signaling module. Our methods are next applied to the more complex phenomenon of cortical oscillations observed in spreading cells. This analysis produces two high fitness hypotheses for the mechanism that underlies this dynamic behavior and suggests experiments to distinguish the hypotheses. The method can be widely applied to other cellular systems to generate and compare alternative hypotheses based on experimentally observed data and using computer simulations.

  1. Electric-current Neutralization, Magnetic Shear, and Eruptive Activity in Solar Active Regions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang; Sun, Xudong [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085 (United States); Török, Tibor; Titov, Viacheslav S. [Predictive Science Inc., 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States); Leake, James E. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2017-09-01

    The physical conditions that determine whether or not solar active regions (ARs) produce strong flares and coronal mass ejections (CMEs) are not yet well understood. Here, we investigate the association between electric-current neutralization, magnetic shear along polarity inversion lines (PILs), and eruptive activity in four ARs: two emerging and two well-developed ones. We find that the CME-producing ARs are characterized by a strongly non-neutralized total current, while the total current in the ARs that did not produce CMEs is almost perfectly neutralized. The difference in the PIL shear between these two groups is much less pronounced, which suggests that the degree of current neutralization may serve as a better proxy for assessing the ability of ARs to produce CMEs.

  2. Human female orgasm as evolved signal: a test of two hypotheses.

    Science.gov (United States)

    Ellsworth, Ryan M; Bailey, Drew H

    2013-11-01

    We present the results of a study designed to empirically test predictions derived from two hypotheses regarding human female orgasm behavior as an evolved communicative trait or signal. One hypothesis tested was the female fidelity hypothesis, which posits that human female orgasm signals a woman's sexual satisfaction and therefore her likelihood of future fidelity to a partner. The other was sire choice hypothesis, which posits that women's orgasm behavior signals increased chances of fertilization. To test the two hypotheses of human female orgasm, we administered a questionnaire to 138 females and 121 males who reported that they were currently in a romantic relationship. Key predictions of the female fidelity hypothesis were not supported. In particular, orgasm was not associated with female sexual fidelity nor was orgasm associated with male perceptions of partner sexual fidelity. However, faked orgasm was associated with female sexual infidelity and lower male relationship satisfaction. Overall, results were in greater support of the sire choice signaling hypothesis than the female fidelity hypothesis. Results also suggest that male satisfaction with, investment in, and sexual fidelity to a mate are benefits that favored the selection of orgasmic signaling in ancestral females.

  3. Seed dormancy and germination - Emerging mechanisms and new hypotheses

    Directory of Open Access Journals (Sweden)

    Hiroyuki eNonogaki

    2014-05-01

    Full Text Available Seed dormancy has played a significant role in adaptation and evolution of seed plants. While its biological significance is clear, molecular mechanisms underlying seed dormancy induction, maintenance and alleviation still remain elusive. Intensive efforts have been made to investigate gibberellin and abscisic acid metabolism in seeds, which greatly contributed to the current understanding of seed dormancy mechanisms. Other mechanisms, which might be independent of hormones, or specific to the seed dormancy pathway, are also emerging from genetic analysis of seed dormancy mutants. These studies suggest that chromatin remodeling through histone ubiquitination, methylation and acetylation, which could lead to transcription elongation or gene silencing, may play a significant role in seed dormancy regulation. Small interfering RNA and/or long non-coding RNA might be a trigger of epigenetic changes at the seed dormancy or germination loci, such as DELAY OF GERMINATION1. While new mechanisms are emerging from genetic studies of seed dormancy, novel hypotheses are also generated from seed germination study with high throughput gene expression analysis. Recent studies on tissue-specific gene expression in tomato and Arabidopsis seeds, which suggested possible mechanosensing in the regulatory mechanisms, advanced our understanding of embryo-endosperm interaction and have potential to re-draw the traditional hypotheses or integrate them into a comprehensive scheme. The progress in basic seed science will enable knowledge translation, another frontier of research to be expanded for food and fuel production.

  4. CURRENT AND KINETIC HELICITY OF LONG-LIVED ACTIVITY COMPLEXES

    International Nuclear Information System (INIS)

    Komm, Rudolf; Gosain, Sanjay

    2015-01-01

    We study long-lived activity complexes and their current helicity at the solar surface and their kinetic helicity below the surface. The current helicity has been determined from synoptic vector magnetograms from the NSO/SOLIS facility, and the kinetic helicity of subsurface flows has been determined with ring-diagram analysis applied to full-disk Dopplergrams from NSO/GONG and SDO/HMI. Current and kinetic helicity of activity complexes follow the hemispheric helicity rule with mainly positive values (78%; 78%, respectively, with a 95% confidence level of 31%) in the southern hemisphere and negative ones (80%; 93%, respectively, with a 95% confidence level of 22% and 14%, respectively) in the northern hemisphere. The locations with the dominant sign of kinetic helicity derived from Global Oscillation Network Group (GONG) and SDO/HMI data are more organized than those of the secondary sign even if they are not part of an activity complex, while locations with the secondary sign are more fragmented. This is the case for both hemispheres even for the northern one where it is not as obvious visually due to the large amount of magnetic activity present as compared to the southern hemisphere. The current helicity shows a similar behavior. The dominant sign of current helicity is the same as that of kinetic helicity for the majority of the activity complexes (83% with a 95% confidence level of 15%). During the 24 Carrington rotations analyzed here, there is at least one longitude in each hemisphere where activity complexes occur repeatedly throughout the epoch. These ''active'' longitudes are identifiable as locations of strong current and kinetic helicity of the same sign

  5. ASIC-like, proton-activated currents in rat hippocampal neurons.

    Science.gov (United States)

    Baron, Anne; Waldmann, Rainer; Lazdunski, Michel

    2002-03-01

    The expression of mRNA for acid sensing ion channels (ASIC) subunits ASIC1a, ASIC2a and ASIC2b has been reported in hippocampal neurons, but the presence of functional hippocampal ASIC channels was never assessed. We report here the first characterization of ASIC-like currents in rat hippocampal neurons in primary culture. An extracellular pH drop induces a transient Na(+) current followed by a sustained non-selective cation current. This current is highly sensitive to pH with an activation threshold around pH 6.9 and a pH(0.5) of 6.2. About half of the total peak current is inhibited by the spider toxin PcTX1, which is specific for homomeric ASIC1a channels. The remaining PcTX1-resistant ASIC-like current is increased by 300 microM Zn(2+) and, whereas not fully activated at pH 5, it shows a pH(0.5) of 6.0 between pH 7.4 and 5. We have previously shown that Zn(2+) is a co-activator of ASIC2a-containing channels. Thus, the hippocampal transient ASIC-like current appears to be generated by a mixture of homomeric ASIC1a channels and ASIC2a-containing channels, probably heteromeric ASIC1a+2a channels. The sustained non-selective current suggests the involvement of ASIC2b-containing heteromeric channels. Activation of the hippocampal ASIC-like current by a pH drop to 6.9 or 6.6 induces a transient depolarization which itself triggers an initial action potential (AP) followed by a sustained depolarization and trains of APs. Zn(2+) increases the acid sensitivity of ASIC channels, and consequently neuronal excitability. It is probably an important co-activator of ASIC channels in the central nervous system.

  6. New hypotheses regarding the Danish health puzzle.

    Science.gov (United States)

    Bakah, May; Raphael, Dennis

    2017-12-01

    Nordic welfare states have achieved admirable population health profiles as a result of public policies that provide economic and social security across the life course. Denmark has been an exception to this rule, as its life expectancies and infant mortality rates since the mid-1970s have lagged behind the other Nordic nations and, in the case of life expectancy, behind most Organisation for Economic Co-operation and Development nations. In this review paper, we identify a number of new hypotheses for why this may be the case. These hypotheses concern the health effects of neo-liberal restructuring of the economy and its institutions, the institution of flexi-security in Denmark's labour market and the influence of Denmark's tobacco and alcohol industries. Also of note is that Denmark experienced higher unemployment rates during its initial period of health stagnation, as well as its treatment of non-Western immigrants and high wealth inequality and, until recently, the fact that Denmark did not systematically address the issue of health inequalities. These hypotheses may serve as covering explanations for the usually provided accounts of elevated behavioural risks and psychosocial stress as being responsible for Denmark's health profile.

  7. Deformational plagiocephaly in normal infants: a systematic review of causes and hypotheses.

    Science.gov (United States)

    De Bock, Freia; Braun, Volker; Renz-Polster, Herbert

    2017-06-01

    Deformational plagiocephaly (DP) is one of the most prevalent abnormal findings in infants and a frequent reason for parents to seek paediatric advice. To systematically review the literature and identify evidence and hypotheses on the aetiology and determinants of DP in otherwise healthy infants. Systematic keyword search in all major biomedical databases to identify peer-reviewed publications reporting (a) empirical research or (b) hypotheses on the aetiology of DP in healthy, term infants. 3150 studies published between 1985 and 2016 and containing relevant keywords were screened. In a two-pronged approach, results were summarised separately for the body of empirical work (22 studies) and the body of hypotheses (110 articles). Only a few empirical studies have examined risk factors in non-selected patient populations on a higher grade methodological level. The most commonly reported risk factors were: male gender, supine sleep position, limited neck rotation or preference in head position, first-born child, lower level of activity and lack of tummy time. Agreement between empirical studies was poor for most exposures, including supine sleep position, tummy time and use of car seats. The articles reporting hypotheses on the aetiology of DP cover a wide field of environmental and biological factors, but include little suggestions as to the potential influence of the everyday care environment of the baby. The evidence on the aetiology of DP is fragmentary and heterogeneous. In addition, factors possibly relevant to the development of DP have not been appreciated in the scientific discussion. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  8. Adolescents' physical activity is associated with previous and current physical activity practice by their parents.

    Science.gov (United States)

    Christofaro, Diego Giulliano Destro; Andersen, Lars Bo; Andrade, Selma Maffei de; Barros, Mauro Virgílio Gomes de; Saraiva, Bruna Thamyres Ciccotti; Fernandes, Rômulo Araújo; Ritti-Dias, Raphael Mendes

    The purpose of this study was to determine whether parents' current and previous physical activity practice is associated with adolescents' physical activity. The sample was composed of 1231 adolescents (14-17 years), and 1202 mothers and 871 fathers were interviewed. Weight and height of the adolescents were measured. Self-reported parents' weight and height were obtained. The current and previous physical activity levels (Baecke's questionnaire) of parents (during childhood and adolescence) and adolescents' physical activity levels were obtained using a questionnaire. The magnitude of the associations between parent and adolescent physical activity levels was determined by binary logistic regression (adjusted by sex, age, and socioeconomic level of adolescents and education level of parents). The current physical activity practice by parents was associated with adolescents' physical activity (p<0.001). The physical activities reported by parents in their childhood and adolescence were also associated with higher physical activity levels among adolescents. Adolescents whose parents were both physically active in the past and present were six times (OR=6.67 [CI=1.94-22.79]) more likely to be physically active compared to adolescents with no parents who were physically active in the past. The current and previous physical activities of parents were associated with higher levels of physical activity in adolescents, even after controlling for confounding factors. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  9. Adolescents' physical activity is associated with previous and current physical activity practice by their parents

    Directory of Open Access Journals (Sweden)

    Diego Giulliano Destro Christofaro

    Full Text Available Abstract Objective: The purpose of this study was to determine whether parents' current and previous physical activity practice is associated with adolescents' physical activity. Methods: The sample was composed of 1231 adolescents (14-17 years, and 1202 mothers and 871 fathers were interviewed. Weight and height of the adolescents were measured. Self-reported parents' weight and height were obtained. The current and previous physical activity levels (Baecke's questionnaire of parents (during childhood and adolescence and adolescents' physical activity levels were obtained using a questionnaire. The magnitude of the associations between parent and adolescent physical activity levels was determined by binary logistic regression (adjusted by sex, age, and socioeconomic level of adolescents and education level of parents. Results: The current physical activity practice by parents was associated with adolescents' physical activity (p < 0.001. The physical activities reported by parents in their childhood and adolescence were also associated with higher physical activity levels among adolescents. Adolescents whose parents were both physically active in the past and present were six times (OR = 6.67 [CI = 1.94-22.79] more likely to be physically active compared to adolescents with no parents who were physically active in the past. Conclusions: The current and previous physical activities of parents were associated with higher levels of physical activity in adolescents, even after controlling for confounding factors.

  10. Singularity hypotheses a scientific and philosophical assessment

    CERN Document Server

    Moor, James; Søraker, Johnny; Steinhart, Eric

    2012-01-01

    Singularity Hypotheses: A Scientific and Philosophical Assessment offers authoritative, jargon-free essays and critical commentaries on accelerating technological progress and the notion of technological singularity. It focuses on conjectures about the intelligence explosion, transhumanism, and whole brain emulation. Recent years have seen a plethora of forecasts about the profound, disruptive impact that is likely to result from further progress in these areas. Many commentators however doubt the scientific rigor of these forecasts, rejecting them as speculative and unfounded. We therefore invited prominent computer scientists, physicists, philosophers, biologists, economists and other thinkers to assess the singularity hypotheses. Their contributions go beyond speculation, providing deep insights into the main issues and a balanced picture of the debate.

  11. On active current selection for Lagrangian profilers

    DEFF Research Database (Denmark)

    Jouffroy, Jerome; Zhou, Qiuyang; Zielinski, Oliver

    2013-01-01

    simple and computationally-efficient control strategies to actively select and use ocean currents so that a profiler can autonomously reach a desired destination. After briefly presenting a typical profiler and possible mechanical modifications for a coastal environment, we introduce simple mathematical...... models for the profiler and the currents it will use. We then present simple feedback controllers that, using the direction of the currents and taking into account the configuration of the environment (coastal or deep-sea), is able to steer the profiler to any desired horizontal location. To illustrate...

  12. Host Lipid Mediators in Leprosy: The Hypothesized Contributions to Pathogenesis

    Directory of Open Access Journals (Sweden)

    Carlos A. M. Silva

    2018-02-01

    Full Text Available The spectrum of clinical forms observed in leprosy and its pathogenesis are dictated by the host’s immune response against Mycobacterium leprae, the etiological agent of leprosy. Previous results, based on metabolomics studies, demonstrated a strong relationship between clinical manifestations of leprosy and alterations in the metabolism of ω3 and ω6 polyunsaturated fatty acids (PUFAs, and the diverse set of lipid mediators derived from PUFAs. PUFA-derived lipid mediators provide multiple functions during acute inflammation, and some lipid mediators are able to induce both pro- and anti-inflammatory responses as determined by the cell surface receptors being expressed, as well as the cell type expressing the receptors. However, little is known about how these compounds influence cellular immune activities during chronic granulomatous infectious diseases, such as leprosy. Current evidence suggests that specialized pro-resolving lipid mediators (SPMs are involved in the down-modulation of the innate and adaptive immune response against M. leprae and that alteration in the homeostasis of pro-inflammatory lipid mediators versus SPMs is associated with dramatic shifts in the pathogenesis of leprosy. In this review, we discuss the possible consequences and present new hypotheses for the involvement of ω3 and ω6 PUFA metabolism in the pathogenesis of leprosy. A specific emphasis is placed on developing models of lipid mediator interactions with the innate and adaptive immune responses and the influence of these interactions on the outcome of leprosy.

  13. Fast inhibition of glutamate-activated currents by caffeine.

    Directory of Open Access Journals (Sweden)

    Nicholas P Vyleta

    Full Text Available BACKGROUND: Caffeine stimulates calcium-induced calcium release (CICR in many cell types. In neurons, caffeine stimulates CICR presynaptically and thus modulates neurotransmitter release. METHODOLOGY/PRINCIPAL FINDINGS: Using the whole-cell patch-clamp technique we found that caffeine (20 mM reversibly increased the frequency and decreased the amplitude of miniature excitatory postsynaptic currents (mEPSCs in neocortical neurons. The increase in mEPSC frequency is consistent with a presynaptic mechanism. Caffeine also reduced exogenously applied glutamate-activated currents, confirming a separate postsynaptic action. This inhibition developed in tens of milliseconds, consistent with block of channel currents. Caffeine (20 mM did not reduce currents activated by exogenous NMDA, indicating that caffeine block is specific to non-NMDA type glutamate receptors. CONCLUSIONS/SIGNIFICANCE: Caffeine-induced inhibition of mEPSC amplitude occurs through postsynaptic block of non-NMDA type ionotropic glutamate receptors. Caffeine thus has both pre and postsynaptic sites of action at excitatory synapses.

  14. The RNA-world and co-evolution hypotheses and the origin of life: Implications, research strategies and perspectives

    Science.gov (United States)

    Lahav, Noam

    1993-12-01

    The applicability of the RNA-world and co-evolution hypotheses to the study of the very first stages of the origin of life is discussed. The discussion focuses on the basic differences between the two hypotheses and their implications, with regard to the reconstruction methodology, ribosome emergence, balance between ribozymes and protein enzymes, and their major difficulties. Additional complexities of the two hypotheses, such as membranes and the energy source of the first reactions, are not treated in the present work. A central element in the proposed experimental strategies is the study of the catalytic activities of very small peptides and RNA-like oligomers, according to existing, as well as to yet-to-be-invented scenarios of the two hypotheses under consideration. It is suggested that the noveldirected molecular evolution technology, andmolecular computational modeling, can be applied to this research. This strategy is assumed to be essential for the suggested goal of future studies of the origin of life, namely, the establishment of a ‘Primordial Darwinian entity’.

  15. Current fluctuations of interacting active Brownian particles

    OpenAIRE

    Pre, Trevor Grand; Limmer, David T.

    2018-01-01

    We derive the distribution function for particle currents for a system of interacting active Brownian particles in the long time limit using large deviation theory and a weighted many body expansion. We find the distribution is non-Gaussian, except in the limit of passive particles. The non-Gaussian fluctuations can be understood from the effective potential the particles experience when conditioned on a given current. This potential suppresses fluctuations of the particle's orientation, and ...

  16. The role of edge current-driven modes in ELM activity

    Energy Technology Data Exchange (ETDEWEB)

    Gimblett, C G; Hastie, R J; Helander, P [EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom)

    2006-10-15

    We propose a model for edge localized mode (ELM) evolution which goes beyond linear stability arguments by hypothesizing that peeling modes initiate a Taylor relaxation (a constrained minimization of the magnetic energy) of an outer annular plasma region. The relaxation has two effects on peeling mode stability: (a) As the relaxation process proceeds radially inwards it leaves in its wake a Taylor state, which for conventional tokamak ordering is simply a flattened equilibrium toroidal current density. This effect acting in isolation would provide a destabilizing effect (for conventional current profiles the edge current density would increase); (b) The formation of a (negative for conventional current profiles) skin current at the plasma-vacuum interface which has a counteracting stabilizing effect on peeling modes. For a finite relaxed annulus, these two opposing effects can balance and give a configuration that is stable to all possible peeling instabilities. The radial extent of the relaxed region required for stability can be calculated using this balance. This then leads to model predictions for ELM characteristics such as the widths and mode numbers, the magnitude of the attendant energy losses and the natural (deterministic) scatter in these quantities. We compare these model predictions with a number of experimentally observed ELM properties. Further, expanding the governing equations gives analytic expressions for ELM widths in terms of localized edge parameters. Peeling modes can occur even when the critical pressure gradient for the onset of ballooning modes has not been reached. For this reason 'type III' ELMs, which typically occur just above the threshold for L-H transitions, may be best described by this model.

  17. The role of edge current-driven modes in ELM activity

    International Nuclear Information System (INIS)

    Gimblett, C G; Hastie, R J; Helander, P

    2006-01-01

    We propose a model for edge localized mode (ELM) evolution which goes beyond linear stability arguments by hypothesizing that peeling modes initiate a Taylor relaxation (a constrained minimization of the magnetic energy) of an outer annular plasma region. The relaxation has two effects on peeling mode stability: (a) As the relaxation process proceeds radially inwards it leaves in its wake a Taylor state, which for conventional tokamak ordering is simply a flattened equilibrium toroidal current density. This effect acting in isolation would provide a destabilizing effect (for conventional current profiles the edge current density would increase); (b) The formation of a (negative for conventional current profiles) skin current at the plasma-vacuum interface which has a counteracting stabilizing effect on peeling modes. For a finite relaxed annulus, these two opposing effects can balance and give a configuration that is stable to all possible peeling instabilities. The radial extent of the relaxed region required for stability can be calculated using this balance. This then leads to model predictions for ELM characteristics such as the widths and mode numbers, the magnitude of the attendant energy losses and the natural (deterministic) scatter in these quantities. We compare these model predictions with a number of experimentally observed ELM properties. Further, expanding the governing equations gives analytic expressions for ELM widths in terms of localized edge parameters. Peeling modes can occur even when the critical pressure gradient for the onset of ballooning modes has not been reached. For this reason 'type III' ELMs, which typically occur just above the threshold for L-H transitions, may be best described by this model

  18. Testing statistical hypotheses

    CERN Document Server

    Lehmann, E L

    2005-01-01

    The third edition of Testing Statistical Hypotheses updates and expands upon the classic graduate text, emphasizing optimality theory for hypothesis testing and confidence sets. The principal additions include a rigorous treatment of large sample optimality, together with the requisite tools. In addition, an introduction to the theory of resampling methods such as the bootstrap is developed. The sections on multiple testing and goodness of fit testing are expanded. The text is suitable for Ph.D. students in statistics and includes over 300 new problems out of a total of more than 760. E.L. Lehmann is Professor of Statistics Emeritus at the University of California, Berkeley. He is a member of the National Academy of Sciences and the American Academy of Arts and Sciences, and the recipient of honorary degrees from the University of Leiden, The Netherlands and the University of Chicago. He is the author of Elements of Large-Sample Theory and (with George Casella) he is also the author of Theory of Point Estimat...

  19. Testing statistical hypotheses of equivalence

    CERN Document Server

    Wellek, Stefan

    2010-01-01

    Equivalence testing has grown significantly in importance over the last two decades, especially as its relevance to a variety of applications has become understood. Yet published work on the general methodology remains scattered in specialists' journals, and for the most part, it focuses on the relatively narrow topic of bioequivalence assessment.With a far broader perspective, Testing Statistical Hypotheses of Equivalence provides the first comprehensive treatment of statistical equivalence testing. The author addresses a spectrum of specific, two-sided equivalence testing problems, from the

  20. Mirror bootstrap method for testing hypotheses of one mean

    OpenAIRE

    Varvak, Anna

    2012-01-01

    The general philosophy for bootstrap or permutation methods for testing hypotheses is to simulate the variation of the test statistic by generating the sampling distribution which assumes both that the null hypothesis is true, and that the data in the sample is somehow representative of the population. This philosophy is inapplicable for testing hypotheses for a single parameter like the population mean, since the two assumptions are contradictory (e.g., how can we assume both that the mean o...

  1. NASA's current activities in free space optical communications

    Science.gov (United States)

    Edwards, Bernard L.

    2017-11-01

    NASA and other space agencies around the world are currently developing free space optical communication systems for both space-to-ground links and space-to-space links. This paper provides an overview of NASA's current activities in free space optical communications with a focus on Near Earth applications. Activities to be discussed include the Lunar Laser Communication Demonstration, the Laser Communications Relay Demonstration, and the commercialization of the underlying technology. The paper will also briefly discuss ongoing efforts and studies for Deep Space optical communications. Finally the paper will discuss the development of international optical communication standards within the Consultative Committee for Space Data Systems.

  2. Current hypotheses on the mechanisms of alcoholism.

    Science.gov (United States)

    Vetreno, R P; Crews, F T

    2014-01-01

    Chronic use of alcohol results in progressive changes to brain and behavior that often lead to the development of alcohol dependence and alcoholism. Although the mechanisms underlying the development of alcoholism remain to be fully elucidated, diminished executive functioning due to hypoactive prefrontal cortex executive control and hyperactive limbic system anxiety and negative emotion might contribute mechanistically to the shift from experimental use to alcoholism and dependence. In the chapter that follows, behavioral deficits associated with cortical dysfunction and neurodegeneration will be related to the behavioral characteristics of alcoholism (e.g., diminished executive function, impulsivity, altered limbic modulation). We will provide evidence that alterations in cyclic AMP-responsive element binding protein (CREB: neurotrophic) and NF-κB (neuroimmune) signaling contribute to the development and persistence of alcoholism. In addition, genetic predispositions and an earlier age of drinking onset will be discussed as contributing factors to the development of alcohol dependence and alcoholism. Overall chronic ethanol-induced neuroimmune gene induction is proposed to alter limbic and frontal neuronal networks contributing to the development and persistence of alcoholism. © 2014 Elsevier B.V. All rights reserved.

  3. Evaluating hypotheses in geolocation on a very large sample of Twitter

    DEFF Research Database (Denmark)

    Salehi, Bahar; Søgaard, Anders

    2017-01-01

    Recent work in geolocation has madeseveral hypotheses about what linguisticmarkers are relevant to detect where peoplewrite from. In this paper, we examinesix hypotheses against a corpus consistingof all geo-tagged tweets from theUS, or whose geo-tags could be inferred,in a 19% sample of Twitter...

  4. Pituitary adenylate cyclase activating polypeptide reduces A-type K+ currents and caspase activity in cultured adult mouse olfactory neurons.

    Science.gov (United States)

    Han, P; Lucero, M T

    2005-01-01

    Pituitary adenylate cyclase activating polypeptide has been shown to reduce apoptosis in neonatal cerebellar and olfactory receptor neurons, however the underlying mechanisms have not been elucidated. In addition, the neuroprotective effects of pituitary adenylate cyclase activating polypeptide have not been examined in adult tissues. To study the effects of pituitary adenylate cyclase activating polypeptide on neurons in apoptosis, we measured caspase activation in adult olfactory receptor neurons in vitro. Interestingly, we found that the protective effects of pituitary adenylate cyclase activating polypeptide were related to the absence of a 4-aminopyridine (IC50=144 microM) sensitive rapidly inactivating potassium current often referred to as A-type current. In the presence of 40 nM pituitary adenylate cyclase activating polypeptide 38, both A-type current and activated caspases were significantly reduced. A-type current reduction by pituitary adenylate cyclase activating polypeptide was blocked by inhibiting the phospholipase C pathway, but not the adenylyl cyclase pathway. Our observation that 5 mM 4-aminopyridine mimicked the caspase inhibiting effects of pituitary adenylate cyclase activating polypeptide indicates that A-type current is involved in apoptosis. This work contributes to our growing understanding that potassium currents are involved with the activation of caspases to affect the balance between cell life and death.

  5. Kolmogorov similarity hypotheses for scalar fields: sampling intermittent turbulent mixing in the ocean and galaxy

    International Nuclear Information System (INIS)

    Gibson, C.H.

    1991-01-01

    Kolmogorov's three universal similarity hypotheses are extrapolated to describe scalar fields like temperature mixed by turbulence. The analogous first and second hypotheses for scalars include the effects of Prandtl number and rate-of-strain mixing. Application of velocity and scalar similarity hypotheses to the ocean must take into account the damping of active turbulence by density stratification and the Earth's rotation to form fossil turbulence. By the analogous Kolmogorov third hypothesis for scalars, temperature dissipation rates χ averaged over lengths r > L K should be lognormally distributed with intermittency factors σ 2 that increase with increasing turbulence energy length scales L O as σ ln r 2 approx = μ θ ln(L O /r). Tests of kolmogorovian velocity and scalar universal similarity hypotheses for very large ranges of turbulence length and timescales are provided by data from the ocean and the galactic interstellar medium. These ranges are from 1 to 9 decades in the ocean, and over 12 decades in the interstellar medium. The universal constant for turbulent mixing intermittency μ θ is estimated from oceanic data to be 0.44±0.01, which is remarkably close to estimates for Kolmorgorov's turbulence intermittency constant μ of 0.45±0.05 from galactic as well as atmospheric data. Extreme intermittency complicates the oceanic sampling problem, and may lead to quantitative and qualitative undersampling errors in estimates of mean oceanic dissipation rates and fluxes. Intermittency of turbulence and mixing in the interstellar medium may be a factor in the formation of stars. (author)

  6. Adaptive hatching hypotheses do not explain asynchronous ...

    African Journals Online (AJOL)

    At the core of the suite of adaptive hatching hypotheses advanced to explain asynchronous hatching in birds is the assumption that if food is not limited then all the hatchlings will develop normally to adulthood. In this study Brown-headed Parrot Poicephalus cryptoxanthus chicks were hand fed and weighed on a daily basis.

  7. NOS CO-OPS Active Currents Data, 6-Minute

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has surface Active Currents data from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS). WARNING: These raw data have not...

  8. Current activities at the MIT Research Reactor

    International Nuclear Information System (INIS)

    Hu Linwen; Bernard, John A.; Harling, Otto K.; Kohse, Gordon E.; Ames, Michael; Olmez, Ilhan

    1998-01-01

    The MIT Research Reactor (MITR) is a MW nuclear research reactor that is owned and operated by the Massachusetts Institute of Technology to further its educational and research goals at both the undergraduate and graduate level. The reactor first achieved criticality in 1958. It was largely rebuilt in 1973/1974 by MIT staff and students, and its current license expires in August 1999. The current facility, which is designated as the MITR-H, uses a compact core with finned, aluminum-clad, plate-type fuel that is cooled and moderated by light water and reflected by heavy water. The reactor core can hold twenty-seven fuel elements. However, the normal configuration is twenty-four elements. A maximum of four fuel elements can be replaced with in-core experimental facilities. A unique feature of the MITR-II's design is that fixed absorber plates can be inserted in the upper half of the core. These cause the flux to peak in the lower half which benefits experimenters and also facilitates a fuel strategy that involves inversion of fuel elements midway through their life cycle. The MITR-II currently operates continuously for four weeks followed by shutdown of a few days for maintenance. This paper provides an overview of current activities at the MITR including preparations for re-licensing. The status of an on-going Phase-I clinical trial of boron neutron capture therapy for both glioblastoma multiforme and metastatic melanoma is described as well as the design of a fission converter facility for BNCT. Environmental research using neutron activation analysis is summarized as well as in-pile research focussed on LWR water chemistry and structural materials. (author)

  9. Inward rectifier potassium current IKir promotes intrinsic pacemaker activity of thalamocortical neurons.

    Science.gov (United States)

    Amarillo, Yimy; Tissone, Angela I; Mato, Germán; Nadal, Marcela S

    2018-06-01

    Slow repetitive burst firing by hyperpolarized thalamocortical (TC) neurons correlates with global slow rhythms (rectifier potassium current I Kir induces repetitive burst firing at slow and delta frequency bands. We demonstrate this in mouse TC neurons in brain slices by manipulating the Kir maximum conductance with dynamic clamp. We also performed a thorough theoretical analysis that explains how the unique properties of I Kir enable this current to induce slow periodic bursting in TC neurons. We describe a new ionic mechanism based on the voltage- and time-dependent interaction of I Kir and hyperpolarization-activated cationic current I h that endows TC neurons with the ability to oscillate spontaneously at very low frequencies, even below 0.5 Hz. Bifurcation analysis of conductance-based models of increasing complexity demonstrates that I Kir induces bistability of the membrane potential at the same time that it induces sustained oscillations in combination with I h and increases the robustness of low threshold-activated calcium current I T -mediated oscillations. NEW & NOTEWORTHY The strong inwardly rectifying potassium current I Kir of thalamocortical neurons displays a region of negative slope conductance in the current-voltage relationship that generates potassium currents activated by hyperpolarization. Bifurcation analysis shows that I Kir induces bistability of the membrane potential; generates sustained subthreshold oscillations by interacting with the hyperpolarization-activated cationic current I h ; and increases the robustness of oscillations mediated by the low threshold-activated calcium current I T . Upregulation of I Kir in thalamocortical neurons induces repetitive burst firing at slow and delta frequency bands (<4 Hz).

  10. The effect of activity history and current activity on static and dynamic postural balance in older adults.

    Science.gov (United States)

    Bulbulian, R; Hargan, M L

    2000-01-01

    The purpose of this study was to investigate the effects of former athleticism and current activity status on static and dynamic postural balance in older adults. Fifty-six subjects participated in four study groups including former athletes, currently active (AA; n = 15; 69.1+/-4.4 years.; 77.8+/-9.8 kg), former athletes, currently inactive (AI; n = 12; 66.7 years.; 87.2+/-15.1 kg), controls currently active (CA; n = 14; 68.6 +/- 4.5 years.; 73.9+/-15 kg), and controls currently inactive (CI; n = 15; 72.8+/-4.8 years; 81.1+/-14.8). All subjects were tested for height, weight, flexibility, thigh circumference, and static (sharpened Romberg/unipedal stance), and dynamic (step length and width) balance tests. The sharpened Romberg (eyes open) test showed that AA (60.0+/-0 s) and CA (59.4+/- 0.5 s) balanced significantly longer than AI (41.5+/-7.2 s), and CI (41.8+/-6.1 s) (punipedal (eyes open) test balance scores for AA, CA, AI, and CI were respectively 40.0+/-4.5, 55.1+/- 3.4, 33.0+/-7.1, and 27.5+/-6.1 s, with CA significantly better than CI (ptest results for relative group comparisons were similar. Overall, two-way analysis of variance showed a significant activity main effect for all dependent variables measured (p<0.05). The results indicated that current activity status plays a key role on balance performance in older adults. Furthermore, former athletic activity history provides no protection for the age related onset of postural imbalance.

  11. History of body weight and physical activity of elderly women differing in current physical activity

    NARCIS (Netherlands)

    Voorrips, L E; Meijers, J H; Sol, P; Seidell, J C; van Staveren, W.A.

    Development of overweight and physical activity during life was studied retrospectively in a group of physically active and a group of sedentary elderly women. The two groups of elderly women were selected based on a validated physical activity questionnaire. A previous study on their current

  12. Cancer stem cell hypotheses: Impact on modern molecular

    Indian Academy of Sciences (India)

    basis for the so-called cancer stem cell (CSC) hypotheses. The first exact proof of CSC ... or less equal ability for tumour regeneration and repopulation. (Nowell 1976 .... Also, there are reports that the 'stemness' (stem-like properties) of brain.

  13. A novel approach to generating CER hypotheses based on mining clinical data.

    Science.gov (United States)

    Zhang, Shuo; Li, Lin; Yu, Yiqin; Sun, Xingzhi; Xu, Linhao; Zhao, Wei; Teng, Xiaofei; Pan, Yue

    2013-01-01

    Comparative effectiveness research (CER) is a scientific method of investigating the effectiveness of alternative intervention methods. In a CER study, clinical researchers typically start with a CER hypothesis, and aim to evaluate it by applying a series of medical statistical methods. Traditionally, the CER hypotheses are defined manually by clinical researchers. This makes the task of hypothesis generation very time-consuming and the quality of hypothesis heavily dependent on the researchers' skills. Recently, with more electronic medical data being collected, it is highly promising to apply the computerized method for discovering CER hypotheses from clinical data sets. In this poster, we proposes a novel approach to automatically generating CER hypotheses based on mining clinical data, and presents a case study showing that the approach can facilitate clinical researchers to identify potentially valuable hypotheses and eventually define high quality CER studies.

  14. Association between Hypothesized Parental Influences and Preschool Children's Physical Activity Behavior

    Science.gov (United States)

    Loprinzi, Paul D.; Schary, David P.; Beets, Michael W.; Leary, Janie; Cardinal, Bradley J.

    2013-01-01

    Background: To date, most research investigating the influence of parents on children"s physical activity behavior has been conducted among school-aged children. As a result, we have a limited understanding of the mechanisms through which parents can influence their young children's physical activity behavior. The purpose of this study was to…

  15. Testing hypotheses involving Cronbach's alpha using marginal models

    NARCIS (Netherlands)

    Kuijpers, R.E.; van der Ark, L.A.; Croon, M.A.

    2013-01-01

    We discuss the statistical testing of three relevant hypotheses involving Cronbach's alpha: one where alpha equals a particular criterion; a second testing the equality of two alpha coefficients for independent samples; and a third testing the equality of two alpha coefficients for dependent

  16. Active current control in wind power plants during grid faults

    DEFF Research Database (Denmark)

    Martinez, Jorge; Kjær, Phillip C.; Rodriguez, Pedro

    2010-01-01

    Modern wind power plants are required and designed to ride through faults in electrical networks, subject to fault clearing. Wind turbine fault current contribution is required from most countries with a high amount of wind power penetration. In order to comply with such grid code requirements......, wind turbines usually have solutions that enable the turbines to control the generation of reactive power during faults. This paper addresses the importance of using an optimal injection of active current during faults in order to fulfil these grid codes. This is of relevant importance for severe...... faults, causing low voltages at the point of common coupling. As a consequence, a new wind turbine current controller for operation during faults is proposed. It is shown that to achieve the maximum transfer of reactive current at the point of common coupling, a strategy for optimal setting of the active...

  17. A Bayesian decision procedure for testing multiple hypotheses in DNA microarray experiments.

    Science.gov (United States)

    Gómez-Villegas, Miguel A; Salazar, Isabel; Sanz, Luis

    2014-02-01

    DNA microarray experiments require the use of multiple hypothesis testing procedures because thousands of hypotheses are simultaneously tested. We deal with this problem from a Bayesian decision theory perspective. We propose a decision criterion based on an estimation of the number of false null hypotheses (FNH), taking as an error measure the proportion of the posterior expected number of false positives with respect to the estimated number of true null hypotheses. The methodology is applied to a Gaussian model when testing bilateral hypotheses. The procedure is illustrated with both simulated and real data examples and the results are compared to those obtained by the Bayes rule when an additive loss function is considered for each joint action and the generalized loss 0-1 function for each individual action. Our procedure significantly reduced the percentage of false negatives whereas the percentage of false positives remains at an acceptable level.

  18. Data-driven efficient score tests for deconvolution hypotheses

    NARCIS (Netherlands)

    Langovoy, M.

    2008-01-01

    We consider testing statistical hypotheses about densities of signals in deconvolution models. A new approach to this problem is proposed. We constructed score tests for the deconvolution density testing with the known noise density and efficient score tests for the case of unknown density. The

  19. Influence of Anodal Transcranial Direct Current Stimulation (tDCS) over the Right Angular Gyrus on Brain Activity during Rest

    Science.gov (United States)

    Clemens, Benjamin; Jung, Stefanie; Mingoia, Gianluca; Weyer, David; Domahs, Frank; Willmes, Klaus

    2014-01-01

    Although numerous studies examined resting-state networks (RSN) in the human brain, so far little is known about how activity within RSN might be modulated by non-invasive brain stimulation applied over parietal cortex. Investigating changes in RSN in response to parietal cortex stimulation might tell us more about how non-invasive techniques such as transcranial direct current stimulation (tDCS) modulate intrinsic brain activity, and further elaborate our understanding of how the resting brain responds to external stimulation. Here we examined how activity within the canonical RSN changed in response to anodal tDCS applied over the right angular gyrus (AG). We hypothesized that changes in resting-state activity can be induced by a single tDCS session and detected with functional magnetic resonance imaging (fMRI). Significant differences between two fMRI sessions (pre-tDCS and post-tDCS) were found in several RSN, including the cerebellar, medial visual, sensorimotor, right frontoparietal, and executive control RSN as well as the default mode and the task positive network. The present results revealed decreased and increased RSN activity following tDCS. Decreased RSN activity following tDCS was found in bilateral primary and secondary visual areas, and in the right putamen. Increased RSN activity following tDCS was widely distributed across the brain, covering thalamic, frontal, parietal and occipital regions. From these exploratory results we conclude that a single session of anodal tDCS over the right AG is sufficient to induce large-scale changes in resting-state activity. These changes were localized in sensory and cognitive areas, covering regions close to and distant from the stimulation site. PMID:24760013

  20. Influence of anodal transcranial direct current stimulation (tDCS) over the right angular gyrus on brain activity during rest.

    Science.gov (United States)

    Clemens, Benjamin; Jung, Stefanie; Mingoia, Gianluca; Weyer, David; Domahs, Frank; Willmes, Klaus

    2014-01-01

    Although numerous studies examined resting-state networks (RSN) in the human brain, so far little is known about how activity within RSN might be modulated by non-invasive brain stimulation applied over parietal cortex. Investigating changes in RSN in response to parietal cortex stimulation might tell us more about how non-invasive techniques such as transcranial direct current stimulation (tDCS) modulate intrinsic brain activity, and further elaborate our understanding of how the resting brain responds to external stimulation. Here we examined how activity within the canonical RSN changed in response to anodal tDCS applied over the right angular gyrus (AG). We hypothesized that changes in resting-state activity can be induced by a single tDCS session and detected with functional magnetic resonance imaging (fMRI). Significant differences between two fMRI sessions (pre-tDCS and post-tDCS) were found in several RSN, including the cerebellar, medial visual, sensorimotor, right frontoparietal, and executive control RSN as well as the default mode and the task positive network. The present results revealed decreased and increased RSN activity following tDCS. Decreased RSN activity following tDCS was found in bilateral primary and secondary visual areas, and in the right putamen. Increased RSN activity following tDCS was widely distributed across the brain, covering thalamic, frontal, parietal and occipital regions. From these exploratory results we conclude that a single session of anodal tDCS over the right AG is sufficient to induce large-scale changes in resting-state activity. These changes were localized in sensory and cognitive areas, covering regions close to and distant from the stimulation site.

  1. Active power compensator of the current harmonics based on the instantaneous power theory

    Directory of Open Access Journals (Sweden)

    Marian GAICEANU

    2005-12-01

    Full Text Available The quality of the electrical current becomes a major concern. The proliferation of the power electronic converters, which are used extensively to control electrical apparatus in industrial and commercial applications (dc and ac variable speed motor drives, induction furnaces, power line conditioners, and industrial power supplies, is at the origin of the AC current distribution network pollution and the reactive power demand. These power electronic converters typically draw non-sinusoidal currents from the utility, causing interference with adjacent sensitive loads and limit the utilization of the available electrical supply. The quality of the electrical current thus becomes a significant concern for the distributors of energy and their customers. Recent progress as regards technology of the power electronics brings a capacity of compensation and correction of the harmonic distortion generated by the nonlinear loads. In this paper a parallel active filter prototype capable of reducing the total harmonic distortion in the supply for most current source or adjustable speed drive type loads is presented. A 33 kVA active power filter was developed for harmonic and reactive power compensation based on the instantaneous power theory. The active filter configuration requires the measurement of both the load and filter currents. Experimental results from a prototype active power filter confirm the suitability of the proposed approach. The actual 33kVA prototype converter has been built and tested in the SIEI S.p.A. (Italy laboratory under the Marie Curie Post Doctoral research. The active power compensator is controlled by a high performance DSP platform, resulting in the following active filter features: source current reduction up to the 25th harmonic, 10% THD achievable for current source type loads, efficiency above 97%, does not cause resonance with other loads, operation in the presence of unbalanced loads, reactive power and harmonics

  2. Toward Valid Measurement of Stephen Pepper's World Hypotheses.

    Science.gov (United States)

    Johnson, John A.

    Two measures of the "world hypotheses" of Stephen Pepper were mailed to 100 sociobiologists, 87 behaviorists, 79 personality psychologists, and 45 human developmentalists. The World Hypothesis Scale (WHS) was designed to measure Pepper's four world views: (1) formism; (2) mechanism; (3) organicism; and (4) contextualism. The…

  3. Active current sheets near the earth's bow shock

    International Nuclear Information System (INIS)

    Schwartz, S.J.; Kessel, R.L.; Brown, C.C.; Woolliscroft, L.J.C.; Dunlop, M.W.; Farrugia, C.J.; Hall, D.S.

    1988-01-01

    The authors present here an investigation of active current sheets observed by the AMPTE UK spacecraft near the Earth's bow shock, concentrating on their macroscopic features and geometry. Events selected primarily by flow directions which deviate substantially from the Sun-Earth line show similar characteristics, including their association with an underlying macroscopic current sheet and a hot central region whose flow direction is organized, at least in part, by location relative to the inferred initial intersection point between the current sheet and the bow shock. This region is flanked by edges which, according to a Rankine-Hugoniot analysis, are often fast shocks whose orientation is consistent with that expected if a bulge on the bow shock convected past the spacecraft. They have found the magnetosheath manifestations of these events which they study in detail. They suggest that these events are the direct result of the disruption and reformation of the bow shock by the passage of an interplanetary current sheet, most probably a tangential discontinuity

  4. What Is the Problem of Ad Hoc Hypotheses?

    Science.gov (United States)

    Bamford, Greg

    1999-01-01

    Philosophers' attempts to convincingly explicate the received view of an ad hoc hypothesis--that it accounts for only the observations it was designed to account for--have been unsuccessful. Familiar and firmer criteria for evaluating the hypotheses or modified theories so classified are characteristically available. Contains 41 references.…

  5. Analysis by nuclear reactions and activations. A current bibliography

    International Nuclear Information System (INIS)

    Bujdoso, E.

    2001-01-01

    A current bibliography based on INIS Atomindex with 78 references on Analysis by nuclear reactions and activations has been prepared for year 1998. References are arranged by first authors' name. (N.T.)

  6. Electroconvulsive therapy's mechanism of action: neuroendocrine hypotheses.

    Science.gov (United States)

    Haskett, Roger F

    2014-06-01

    Despite a range of etiological theories since the introduction of electroconvulsive therapy (ECT) more than 75 years ago, its mechanism of action remains poorly understood. The neuroendocrine hypothesis is based on the seizure-related release of hypothalamic hormones into the blood and cerebrospinal fluid and evidence of endocrine dysfunction in many patients with severe mood disorder. The specific effect of ECT was hypothesized to result from the transverse passage of current through the brain with direct stimulation of axial structures including the diencephalon. The prompt release of adrenocorticotropic hormone, cortisol, and prolactin into blood followed ECT with a return to pretreatment baseline levels in several hours. The elevated levels of hormones were absorbed by the cerebrospinal fluid, providing contact with brain cells and central nervous system structures. An apparently specific pattern of ECT-induced hormone changes, limited to prolactin and cortisol, suggested that ECT released a substance with dopaminergic antagonist and antipsychotic properties. As hypothalamic dysfunction is a key finding in endogenomorphic depression and the abnormal endocrine and physiological functions usually normalize with recovery, this led to a search for biological markers that would supplement clinical assessment of diagnosis and treatment response. One of these, the overnight dexamethasone suppression test found that 40% to 50% of melancholic depressed patients had abnormal results, whereas 90% of control patients suppressed normally. This was followed by a period of uncritical overenthusiasm followed by wholesale rejection of the clinical neuroendocrine strategies. Several key methodological issues received inadequate attention, and there have been calls to revisit this topic.

  7. Control algorithms based on the active and non-active currents for a UPQC without series transformers

    OpenAIRE

    Correa Monteiro, Luis Fernando; Aredes, Mauricio; Pinto, J. G.; Exposto, Bruno; Afonso, João L.

    2016-01-01

    This study presents control algorithms for a new unified power quality conditioner (UPQC) without the series transformers that are frequently used to make the insertion of the series converter of the UPQC between the power supply and the load. The behaviour of the proposed UPQC is evaluated in presence of voltage imbalances, as well as under non-sinusoidal voltage-and current conditions. The presented algorithms derive from the concepts involving the active and non-active currents, together w...

  8. Revisiting the environmental Kuznets curve and pollution haven hypotheses: MIKTA sample.

    Science.gov (United States)

    Bakirtas, Ibrahim; Cetin, Mumin Atalay

    2017-08-01

    This study aims to examine the validity of the environmental Kuznets curve (EKC) and pollution haven hypotheses in Mexico, Indonesia, South Korea, Turkey, and Australia (MIKTA) countries from 1982 to 2011 by using a panel vector auto regressive (PVAR) model. Empirical findings imply that the EKC hypothesis is rejected by the MIKTA sample. However, PVAR estimations reveal Granger causality from income level, foreign direct investment (FDI) inward, and energy consumption to CO 2 emissions. Orthogonalized impulse-response functions are derived from PVAR estimations. According to the analysis results, the response of CO 2 emissions to a shock on FDI is positive. These results assert that FDI has a detrimental effect on environmental quality in MIKTA countries which means the pollution haven hypothesis is confirmed by the MIKTA sample. Therefore, MIKTA countries should revise their current economic growth plans to provide sustainable development and also re-organize their legal infrastructure to induce usage of renewable energy sources.

  9. Black/White Differences in Adolescent Drug Use: A Test of Six Hypotheses

    Science.gov (United States)

    Rote, Sunshine M.; Taylor, John

    2014-01-01

    Six specific hypotheses have been developed to account for why Caucasians have higher rates of drug use compared to African-Americans. This article utilizes data from a South Florida-based community study of 893 young adults (1998-2002) to test these hypotheses. Specifically, Caucasians (1) initiate drug use at younger ages than African-Americans…

  10. Human memory research: Current hypotheses and new perspectives

    Directory of Open Access Journals (Sweden)

    Antônio Jaeger

    Full Text Available Abstract Research on human memory has increased significantly in the last few decades. Inconsistencies and controversies inherent to such research, however, are rarely articulated on published reports. The goal of the present article is to present and discuss a series of open questions related to major topics on human memory research that can be addressed by future research. The topics covered here are visual working memory, recognition memory, emotion and memory interaction, and methodological issues of false memories studies. Overall, the present work reveals a series of open questions and alternative analysis which could be useful for the process of hypothesis generation, and consequently for the design and implementation of future research on human memory.

  11. Current hypotheses and research milestones in Alzheimer's disease

    National Research Council Canada - National Science Library

    Maccioni, Ricardo B; Perry, George

    2009-01-01

    .... This book contains 20 seminal chapters by authors with different views that in a multidisciplinary approach focus on the main issues of neuroanatomical, neuropathological, neuropsychological, neurological, and molecular biological aspects of AD. The idea for this collection arose during the preparation of the proceedings for the International Summit Meeting...

  12. Current Hypotheses on How Microsatellite Instability Leads to Enhanced Survival of Lynch Syndrome Patients

    Directory of Open Access Journals (Sweden)

    Kristen M. Drescher

    2010-01-01

    Full Text Available High levels of microsatellite instability (MSI-high are a cardinal feature of colorectal tumors from patients with Lynch Syndrome. Other key characteristics of Lynch Syndrome are that these patients experience fewer metastases and have enhanced survival when compared to patients diagnosed with microsatellite stable (MSS colorectal cancer. Many of the characteristics associated with Lynch Syndrome including enhanced survival are also observed in patients with sporadic MSI-high colorectal cancer. In this review we will present the current state of knowledge regarding the mechanisms that are utilized by the host to control colorectal cancer in Lynch Syndrome and why these same mechanisms fail in MSS colorectal cancers.

  13. Current hypotheses on how microsatellite instability leads to enhanced survival of Lynch Syndrome patients.

    Science.gov (United States)

    Drescher, Kristen M; Sharma, Poonam; Lynch, Henry T

    2010-01-01

    High levels of microsatellite instability (MSI-high) are a cardinal feature of colorectal tumors from patients with Lynch Syndrome. Other key characteristics of Lynch Syndrome are that these patients experience fewer metastases and have enhanced survival when compared to patients diagnosed with microsatellite stable (MSS) colorectal cancer. Many of the characteristics associated with Lynch Syndrome including enhanced survival are also observed in patients with sporadic MSI-high colorectal cancer. In this review we will present the current state of knowledge regarding the mechanisms that are utilized by the host to control colorectal cancer in Lynch Syndrome and why these same mechanisms fail in MSS colorectal cancers.

  14. Twelve testable hypotheses on the geobiology of weathering

    Science.gov (United States)

    S.L. Brantley; J.P. Megonigal; F.N. Scatena; Z. Balogh-Brunstad; R.T. Barnes; M.A. Bruns; P. van Cappelen; K. Dontsova; H.E. Hartnett; A.S. Hartshorn; A. Heimsath; E. Herndon; L. Jin; C.K. Keller; J.R. Leake; W.H. McDowell; F.C. Meinzer; T.J. Mozdzer; S. Petsch; J. Pett-Ridge; K.S. Pretziger; P.A. Raymond; C.S. Riebe; K. Shumaker; A. Sutton-Grier; R. Walter; K. Yoo

    2011-01-01

    Critical Zone (CZ) research investigates the chemical, physical, and biological processes that modulate the Earth's surface. Here, we advance 12 hypotheses that must be tested to improve our understanding of the CZ: (1) Solar-to-chemical conversion of energy by plants regulates flows of carbon, water, and nutrients through plant-microbe soil networks, thereby...

  15. Transfer factor - hypotheses for its structure and function.

    Science.gov (United States)

    Shifrine, M; Scibienski, R

    1975-01-01

    Transfer factor (TF) is a dialyzable extract from primed lymphocytes that is able to transfer specific delayed hypersensitivity from one animal to another. On the basis of available data we suggest that TF is a polypeptide with a molecular weight below 15,000 daltons. We hypothesize that TF is the variable light or heavy chain domain of immunoglobulin: such a molecule conforms with the accepted properties of TF and also has the necessary specificity requirements. We also hypothesize that TF is part of a receptor site. beta-2-microglobulin, a molecule that is an integral part of cell surfaces, could be the anchor for TF. beta-2-microglobulin has homologies with the constant portion of immunoglobulin light or heavy chain and thus would combine with the variable domain (TF) to form a complete receptor site for a specific antigen. The properties of TF suggest its mode of action, which is discussed in detail in the text. The biologic advantages of TF is its ability to confer immediate (immunologie specific) protection while the 'normal' immune response develops.

  16. 5-HT modulation of hyperpolarization-activated inward current and calcium- dependent outward current in a crustacean motor neuron

    DEFF Research Database (Denmark)

    Kiehn, O.; Harris-Warrick, R. M.

    1992-01-01

    1. Serotonergic modulation of a hyperpolarization-activated inward current, I(h), and a calcium-dependent outward current, I(o(Ca)), was examined in the dorsal gastric (DG) motor neuron, with the use of intracellular recording techniques in an isolated preparation of the crab stomatogastric....... The time course of activation of I(h) was well fitted by a single exponential function and strongly voltage dependent. 5-HT increased the rate of activation of I(h). 5- HT also slowed the rate of deactivation of the I(h) tail on repolarization to -50 mV. 6. The activation curve for the conductance (G...... reduced or eliminated the 5-HT response in the depolarizing range, suggesting that 5-HT specifically reduces I(o(Ca)). 11. These results demonstrate that 5-HT has dual effects on the DG motor neuron, in the crab stomatogastric ganglion. We suggest that changes in the two conductances are responsible...

  17. A survey of etiologic hypotheses among testicular cancer researchers

    DEFF Research Database (Denmark)

    Stang, A; Trabert, B; Rusner, C

    2015-01-01

    Basic research results can provide new ideas and hypotheses to be examined in epidemiological studies. We conducted a survey among testicular cancer researchers on hypotheses concerning the etiology of this malignancy. All researchers on the mailing list of Copenhagen Testis Cancer Workshops...... and corresponding authors of PubMed-indexed articles identified by the search term 'testicular cancer' and published within 10 years (in total 2750 recipients) were invited to respond to an e-mail-based survey. Participants of the 8th Copenhagen Testis Cancer Workshop in May 2014 were subsequently asked to rate...... that scored as most plausible. We also present plans for improving the survey that may be repeated at a next international meeting of experts in testicular cancer. Overall 52 of 99 (53%) registered participants of the 8th Copenhagen Testis Cancer Workshop submitted the plausibility rating form. Fourteen of 27...

  18. Light and sporadic physical activity overlooked by current guidelines makes older women more active than older men.

    Science.gov (United States)

    Amagasa, Shiho; Fukushima, Noritoshi; Kikuchi, Hiroyuki; Takamiya, Tomoko; Oka, Koichiro; Inoue, Shigeru

    2017-05-02

    Men are generally believed to be more physically active than women when evaluated using current physical activity (PA) guidelines, which count only moderate-to-vigorous physical activity (MVPA) in bouts lasting at least 10 min. However, it remains unclear men are truly more physically active provided that all-intensity PA are evaluated. This population based cross-sectional study aimed to examine gender differences in patterns of objectively-assessed PA in older adults. One thousand two hundred ten community-dwelling Japanese older adults who were originally randomly selected from residential registry of three municipalities were asked to respond a questionnaire and wear an accelerometer (HJA-350IT, Omron Healthcare). The prevalence of achieving current PA guidelines, ≥150 min/week MVPA in bouts lasting at least 10 min, was calculated. Gender differences in volume of each-intensity activity (METs-hour) were assessed by analysis of covariance after adjustment for age and wear time. Data from 450 (255 men, mean 74 years) participants who had valid accelerometer data were analyzed. Women were less likely to meet the guidelines (men: 31.0, women: 21.5%; p women accumulated more light-intensity PA (LPA) and short-bout (1-9 min) MVPA, and thus established higher total volume of PA (men: 22.0 METs-hour/day, women: 23.9 METs-hour/day) (p women were less active when evaluated against current PA guidelines, but more active by total PA. Considering accumulated evidence on health benefits of LPA and short-bout MVPA, our findings highlight the potential for the limitation of assessing PA using current PA guidelines.

  19. Design and implementation of predictive filtering system for current reference generation of active power filter

    Energy Technology Data Exchange (ETDEWEB)

    Kilic, Tomislav; Milun, Stanko; Petrovic, Goran [FESB University of Split, Faculty of Electrical Engineering, Machine Engineering and Naval Architecture, R. Boskovica bb, 21000, Split (Croatia)

    2007-02-15

    The shunt active power filters are used to attenuate the harmonic currents in power systems by injecting equal but opposite compensating currents. Successful control of the active filters requires an accurate current reference. In this paper the current reference determination based on predictive filtering structure is presented. Current reference was obtained by taking the difference of load current and its fundamental harmonic. For fundamental harmonic determination with no time delay a combination of digital predictive filter and low pass filter is used. The proposed method was implemented on a laboratory prototype of a three-phase active power filter. The algorithm for current reference determination was adapted and implemented on DSP controller. Simulation and experimental results show that the active power filter with implemented predictive filtering structure gives satisfactory performance in power system harmonic attenuation. (author)

  20. ADOPTING SOCIO-DEMOGRAPHIC CHARACTERISTICS IN PROFILING GREEN CONSUMERS: A REVIEW OF HYPOTHESES

    Directory of Open Access Journals (Sweden)

    Arif Hartono

    2009-02-01

    Full Text Available In the last three decades worldwide environmental consciousness has increased dramatically as well as profiling green consumers have gained tremendous attention in the past. Segmenting and targeting markets base on pro-environmental purchase behavior are essential when companies positioning their green products. Socio-demographic characteristics have gained a lot of attention as the key profiling variables. Such characteristics have been employed by many scholars more frequently for the bases of segmenting and profiling green consumers. However, most existing studies of green consumers’ socio-demographic were US based. The present article attempts to review the common hypotheses of socio-demographic characteristics in profiling green consumers. The present article reviews five general hypotheses relating to socio-demographics and environmental consciousness of green consumers, namely the gender, age, education level, income, and occupation hypotheses, as well as the theoretical explanation for each hypothesis. Most previous studies tend to have the same conclusion in the gender, age, education level, and  income characteristics. Critics to socio-demographic characteristics and a need to conduct green marketing research in Indonesia was also reviewed.Key words: profiling, socio-demographic, green consumer, hypotheses.

  1. Landscape moderation of biodiversity patterns and processes - eight hypotheses

    NARCIS (Netherlands)

    Tscharntke, T.; Tylianakis, J.M.; Rand, T.A.; Didham, R.K.; Fahrig, L.; Batary, P.; Bengtsson, J.; Clough, Y.; Crist, T.O.; Dormann, C.; Ewers, R.M.; Frund, J.; Holt, R.D.; Holzschuh, A.; Klein, A.M.; Kleijn, D.; Kremen, C.; Landis, D.A.; Laurance, W.F.; Lindenmayer, D.B.; Scherber, C.; Sodhi, N.; Steffan-Dewenter, I.; Thies, C.; Putten, van der W.H.; Westphal, C.

    2012-01-01

    Understanding how landscape characteristics affect biodiversity patterns and ecological processes at local and landscape scales is critical for mitigating effects of global environmental change. In this review, we use knowledge gained from human-modified landscapes to suggest eight hypotheses, which

  2. Towards Self-Learning Based Hypotheses Generation in Biomedical Text Domain.

    Science.gov (United States)

    Gopalakrishnan, Vishrawas; Jha, Kishlay; Xun, Guangxu; Ngo, Hung Q; Zhang, Aidong

    2017-12-26

    The overwhelming amount of research articles in the domain of bio-medicine might cause important connections to remain unnoticed. Literature Based Discovery is a sub-field within biomedical text mining that peruses these articles to formulate high confident hypotheses on possible connections between medical concepts. Although many alternate methodologies have been proposed over the last decade, they still suffer from scalability issues. The primary reason, apart from the dense inter-connections between biological concepts, is the absence of information on the factors that lead to the edge-formation. In this work, we formulate this problem as a collaborative filtering task and leverage a relatively new concept of word-vectors to learn and mimic the implicit edge-formation process. Along with single-class classifier, we prune the search-space of redundant and irrelevant hypotheses to increase the efficiency of the system and at the same time maintaining and in some cases even boosting the overall accuracy. We show that our proposed framework is able to prune up to 90% of the hypotheses while still retaining high recall in top-K results. This level of efficiency enables the discovery algorithm to look for higher-order hypotheses, something that was infeasible until now. Furthermore, the generic formulation allows our approach to be agile to performboth open and closed discovery.We also experimentally validate that the core data-structures upon which the system bases its decision has a high concordance with the opinion of the experts.This coupled with the ability to understand the edge formation process provides us with interpretable results without any manual intervention. The relevant JAVA codes are available at: https://github.com/vishrawas/Medline-Code_v2. vishrawa@buffalo.edukishlayj@buffalo.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email

  3. New digital reference current generation for shunt active power filter under distorted voltage conditions

    Energy Technology Data Exchange (ETDEWEB)

    Abdusalam, Mohamed; Karimi, Shahram; Saadate, Shahrokh [Groupe de Recherche en Electrotechnique et Electronique de Nancy (GREEN), CNRS UMR 7037 (France); Poure, Philippe [Laboratoire d' Instrumentation Electronique de Nancy (LIEN), EA 3440, Universite Henri Poincare - Nancy Universite, B.P. 239, 54506 Vandoeuvre les Nancy Cedex (France)

    2009-05-15

    In this paper, a new reference current computation method suitable for shunt active power filter control under distorted voltage conditions is proposed. The active power filter control is based on the use of self-tuning filters (STF) for the reference current generation and on a modulated hysteresis current controller. This active filter is intended for harmonic compensation of a diode rectifier feeding a RL load under distorted voltage conditions. The study of the active filter control is divided in two parts. The first one deals with the harmonic isolator which generates the harmonic reference currents and is experimentally implemented in a DS1104 card of a DSPACE prototyping system. The second part focuses on the generation of the switching pattern of the inverter by using a modulated hysteresis current controller, implemented in an analogue card. The use of STF instead of classical extraction filters allows extracting directly the voltage and current fundamental components in the {alpha}-{beta} axis without phase locked loop (PLL). The performances are good even under distorted voltage conditions. First, the effectiveness of the new proposed method is mathematically studied and verified by computer simulation. Then, experimental results are presented using a DSPACE system associated with the analogue current controller for a real shunt active power filter. (author)

  4. Silicone Substrate with Collagen and Carbon Nanotubes Exposed to Pulsed Current for MSC Osteodifferentiation

    Directory of Open Access Journals (Sweden)

    Daniyal Jamal

    2017-01-01

    Full Text Available Autologous human adipose tissue-derived mesenchymal stem cells (MSCs have the potential for clinical translation through their induction into osteoblasts for regeneration. Bone healing can be driven by biophysical stimulation using electricity for activating quiescent adult stem cells. It is hypothesized that application of electric current will enhance their osteogenic differentiation, and addition of conductive carbon nanotubes (CNTs to the cell substrate will provide increased efficiency in current transmission. Cultured MSCs were seeded and grown onto fabricated silicone-based composites containing collagen and CNT fibers. Chemical inducers, namely, glycerol phosphate, dexamethasone, and vitamin C, were then added to the medium, and pulsatile submilliampere electrical currents (about half mA for 5 cycles at 4 mHz, twice a week were applied for two weeks. Calcium deposition indicative of MSC differentiation and osteoblastic activity was quantified through Alizarin Red S and spectroscopy. It was found that pulsed current significantly increased osteodifferentiation on silicone-collagen films without CNTs. Under no external current, the presence of 10% (m/m CNTs led to a significant and almost triple upregulation of calcium deposition. Both CNTs and current parameters did not appear to be synergistic. These conditions of enhanced osteoblastic activities may further be explored ultimately towards future therapeutic use of MSCs.

  5. Obesity and Cancer: Existing and New Hypotheses for a Causal Connection

    Directory of Open Access Journals (Sweden)

    Trevor W. Stone

    2018-04-01

    Full Text Available Existing explanations of obesity-associated cancer emphasise direct mutagenic effects of dietary components or hormonal imbalance. Some of these hypotheses are reviewed briefly, but recent evidence suggests a major role for chronic inflammation in cancer risk, possibly involving dietary content. These ideas include the inflammation-induced activation of the kynurenine pathway and its role in feeding and metabolism by activation of the aryl hydrocarbon receptor (AHR and by modulating synaptic transmission in the brain. Evidence for a role of the kynurenine pathway in carcinogenesis then provides a potentially major link between obesity and cancer. A second new hypothesis is based on evidence that serine proteases can deplete cells of the tumour suppressors Deleted in Colorectal Cancer (DCC and neogenin. These enzymes include mammalian chymotryptic proteases released by pro-inflammatory neutrophils and macrophages. Blood levels of chymotrypsin itself increase in parallel with food intake. The mechanistically similar bacterial enzyme subtilisin is widespread in the environment, animal probiotics, meat processing and cleaning products. Simple public health schemes in these areas, with selective serine protease inhibitors and AHR antagonists and could prevent a range of intestinal and other cancers. Keywords: Obesity, Serine proteases, Chymotrypsin, Subtilisin, Dependence receptors, DCC, Kynurenine

  6. How the mainstream limits the spreading of alternative hypotheses

    Science.gov (United States)

    Kalenda, Pavel

    2014-05-01

    that prof. Djuric had tried for more than 10 years to publish this article in various peer-reviewed journals. So, prof. Djuric got into the official book (list) of "scientific dissidents" among hundreds of other professors and doctors of science (De Climont 2012). These "scientific dissidents" do not have access to established journals and may possibly publish privately or at best on the web in marginal journals whose list was published by De Climont (2012). Such a marginal journal in the field of geophysics and geology is New Concepts in Global Tectonics. This journal has been established because the current hypothesis about the movement of the continents due to convection currents in the mantle becomes under the weight of new observation quite untenable. 4) Scientific consensus History has known many hypotheses that were accepted as proven truth but later, in the light of new knowledge, they completely failed. - No one has the right to decide which scientific hypotheses will be accepted and which will not get into print. Perhaps the worst situation is in climatology (due to global effects and impacts), when the plenary session of IPCC consensually stated that the current global warming was mainly due to the human activity. References De Climont, J. (2012): The worldwide list of dissident scientists. http://astrojan.hostei.com/droa.htm. Djurič, J. (2006): Unification Of Gravitation And Electromagnetism. http://jovandjuric.tripod.com/ David H. Douglass, John R. Christy, Benjamin D. Pearson and S. Fred Singer (2007): A comparison of tropical temperature trends with model predictions. International Journal of Climatology, Volume 28, Issue 13, 15 November 2008, Pages: 1693-1701. http://onlinelibrary.wiley.com/doi/10.1002/joc.1651/pdf. Einstein, A. : List of scientific publications by Albert Einstein. /wiki/List_of_scientific_publications_by_Albert_Einstein. Kolínský, P., Valenta, J. and Gaždová, R. (2012): Seismicity, groundwater level variations and earth tides in

  7. GRS current activities in East-European countries overview

    International Nuclear Information System (INIS)

    Teske, H.; Janke, R.

    2001-01-01

    This report presents the following items: agreement between the Federal Government and Utility Companies about the future utilization of the existing nuclear power plants in Germany, June 2001; GRS current activities in the Eastern European countries; science-technical co-operation with Russia; assessment of safety significance of the events for German NPP; Leningrad in-depth safety assessment, co-operation SEC NRS and GRS

  8. Common catabolic enzyme patterns in a microplankton community of the Humboldt Current System off northern and central-south Chile: Malate dehydrogenase activity as an index of water-column metabolism in an oxygen minimum zone

    Science.gov (United States)

    González, R. R.; Quiñones, R. A.

    2009-07-01

    An extensive subsurface oxygen minimum zone off northern and central-south Chile, associated with the Peru-Chile undercurrent, has important effects on the metabolism of the organisms inhabiting therein. Planktonic species deal with the hypoxic and anoxic environments by relying on biochemical as well as physiological processes related to their anaerobic metabolisms. Here we characterize, for the first time, the potential enzymatic activities involved in the aerobic and anaerobic energy production pathways of microplanktonic organisms (oxygen concentration and microplanktonic biomass in the oxygen minimum zone and adjacent areas of the Humboldt Current System water column. Our results demonstrate significant potential enzymatic activity of catabolic pathways in the oxygen minimum zone. Malate dehydrogenase had the highest oxidizing activity of nicotinamide adenine dinucleotide (reduced form) in the batch of catabolic enzymatic activities assayed, including potential pyruvate oxidoreductases activity, the electron transport system, and dissimilatory nitrate reductase. Malate dehydrogenase correlated significantly with almost all the enzymes analyzed within and above the oxygen minimum zone, and also with the oxygen concentration and microplankton biomass in the water column of the Humboldt Current System, especially in the oxygen minimum zone off Iquique. These results suggest a possible specific pattern for the catabolic activity of the microplanktonic realm associated with the oxygen minimum zone spread along the Humboldt Current System off Chile. We hypothesize that malate dehydrogenase activity could be an appropriate indicator of microplankton catabolism in the oxygen minimum zone and adjacent areas.

  9. Testing Hypotheses About Glacial Cycles Against the Observational Record

    DEFF Research Database (Denmark)

    Kaufmann, Robert; Juselius, Katarina

    2013-01-01

    We estimate an identified cointegrated vector autoregression (CVAR) model of the climate system to test hypotheses about the physical mechanisms that may drive glacial cycles during the late Pleistocene. Results indicate that a permanent doubling of CO2 generates a 11.1oC rise in Antarctic...

  10. Passivity enhancement by series LC filtered active damper with zero current reference

    DEFF Research Database (Denmark)

    Bai, Haofeng; Wang, Xiongfei; Blaabjerg, Frede

    2016-01-01

    can be improved by enhancing the passivity of the total admittance seen by the grid, which allows for a zero current reference and a much simpler current controller for the active damper. To show the performance of the active damper with zero reference, this paper first carries out the impedance based...... stability analysis of grid converters in the weak grid. Based on the impedance model of the series LC filtered active damper, the real part of its output admittance is investigated and shown to be able to enhance the passivity of the admittance of the converters seen by the grid. Finally, simulation...

  11. A cyclic GMP-dependent calcium-activated chloride current in smooth-muscle cells from rat mesenteric resistance arteries

    DEFF Research Database (Denmark)

    Matchkov, Vladimir; Aalkjær, Christian; Nilsson, Holger

    2004-01-01

    We have previously demonstrated the presence of a cyclic GMP (cGMP)-dependent calcium-activated inward current in vascular smooth-muscle cells, and suggested this to be of importance in synchronizing smooth-muscle contraction. Here we demonstrate the characteristics of this current. Using......M) in the pipette solution. The current was found to be a calcium-activated chloride current with an absolute requirement for cyclic GMP (EC50 6.4 microM). The current could be activated by the constitutively active subunit of PKG. Current activation was blocked by the protein kinase G antagonist Rp-8-Br-PET-cGMP...... differed from those of the calcium-activated chloride current in pulmonary myocytes, which was cGMP-independent, exhibited a high sensitivity to inhibition by niflumic acid, was unaffected by zinc ions, and showed outward current rectification as has previously been reported for this current. Under...

  12. Muscarinic activation of Ca2+-activated Cl- current in interstitial cells of Cajal.

    Science.gov (United States)

    Zhu, Mei Hong; Sung, In Kyung; Zheng, Haifeng; Sung, Tae Sik; Britton, Fiona C; O'Driscoll, Kate; Koh, Sang Don; Sanders, Kenton M

    2011-09-15

    Interstitial cells of Cajal (ICC) provide pacemaker activity and functional bridges between enteric motor nerve terminals and gastrointestinal smooth muscle cells. The ionic conductance(s) in ICC that are activated by excitatory neural inputs are unknown. Transgenic mice (Kit(copGFP/+)) with constitutive expression of a bright green fluorescent protein were used to investigate cellular responses of ICC to cholinergic stimulation. ICC displayed spontaneous transient inward currents (STICs) under voltage clamp that corresponded to spontaneous transient depolarizations (STDs) under current clamp. STICs reversed at 0 mV when E(Cl) = 0 mV and at -40 mV when E(Cl) was -40 mV, suggesting the STICs were due to a chloride conductance. Carbachol (CCh, 100 nm and 1 μm) induced a sustained inward current (depolarization in current clamp) and increased the amplitude and frequency of STICs and STDs. CCh responses were blocked by atropine (10 μm) or 4-DAMP (100 nm), an M(3) receptor antagonist. STDs were blocked by niflumic acid and 5-nitro-2-(3-phenylpropylamino)-benzoic acid (both 100 μm), and CCh had no effect in the presence of these drugs. The responses of intact circular muscles to CCh and stimulation of intrinsic excitatory nerves by electrical field stimulation (EFS) were also compared. CCh (1 μm) caused atropine-sensitive depolarization and increased the maximum depolarization of slow waves. Similar atropine-sensitive responses were elicited by stimulation of intrinsic excitatory neurons. Niflumic acid (100 μm) blocked responses to EFS but had minor effect on responses to exogenous CCh. These data suggest that different ionic conductances are responsible for electrical responses elicited by bath-applied CCh and cholinergic nerve stimulation.

  13. Advancing the literature on designing audit and feedback interventions: identifying theory-informed hypotheses.

    Science.gov (United States)

    Colquhoun, Heather L; Carroll, Kelly; Eva, Kevin W; Grimshaw, Jeremy M; Ivers, Noah; Michie, Susan; Sales, Anne; Brehaut, Jamie C

    2017-09-29

    Audit and feedback (A&F) is a common strategy for helping health providers to implement evidence into practice. Despite being extensively studied, health care A&F interventions remain variably effective, with overall effect sizes that have not improved since 2003. Contributing to this stagnation is the fact that most health care A&F interventions have largely been designed without being informed by theoretical understanding from the behavioral and social sciences. To determine if the trend can be improved, the objective of this study was to develop a list of testable, theory-informed hypotheses about how to design more effective A&F interventions. Using purposive sampling, semi-structured 60-90-min telephone interviews were conducted with experts in theories related to A&F from a range of fields (e.g., cognitive, health and organizational psychology, medical decision-making, economics). Guided by detailed descriptions of A&F interventions from the health care literature, interviewees described how they would approach the problem of designing improved A&F interventions. Specific, theory-informed hypotheses about the conditions for effective design and delivery of A&F interventions were elicited from the interviews. The resulting hypotheses were assigned by three coders working independently into themes, and categories of themes, in an iterative process. We conducted 28 interviews and identified 313 theory-informed hypotheses, which were placed into 30 themes. The 30 themes included hypotheses related to the following five categories: A&F recipient (seven themes), content of the A&F (ten themes), process of delivery of the A&F (six themes), behavior that was the focus of the A&F (three themes), and other (four themes). We have identified a set of testable, theory-informed hypotheses from a broad range of behavioral and social science that suggest conditions for more effective A&F interventions. This work demonstrates the breadth of perspectives about A&F from non

  14. Comparative study of microcontroller controlled four-wire voltage and current source shunt active power filters

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, S.

    2009-07-01

    During the past two decades, active power filters have increasingly grown their popularity as a viable method for improving electric power quality. The main reasons for this have been the advent of fast self-commutating solid-state devices, the progression of digital technology and the improved sensor technology. Four-wire active power filters provide an efficient solution for improving the quality of supply in grounded three-phase systems or three-phase systems with neutral conductors, which are commonly used for powering residential, office and public buildings. Four-wire active power filters are applicable in compensating current harmonics, reactive power, neutral current and load phase imbalance.This thesis presents a comparative study of microcontroller controlled four-wire voltage and current source shunt active power filters. The study includes two voltage source topologies and a current source topology with two different dc-link energy storage structures, which are compared on the basis of their filtering properties, filtering performance and efficiency. The obtained results are used for determining the suitability of current source technology for four-wire active power filtering and finding the most viable four-wire shunt active power filter topology. One commonly recognized disadvantage of the current source active power filter has always been the bulky dc-link inductor. To reduce the size of the dc-link inductor, an alternative dc-link structure for current source active power filters was introduced in the late 80's. The hybrid energy storage consists of both inductive and capacitive energy storage elements, two diodes and two controllable semiconductor switching devices. Since the capacitive element is used as a main storage unit, the inductance of the dc-link inductor can be considerably reduced. However, the original dc current control method proposed is not able to utilize the full potential of the hybrid energy storage and the inductance

  15. Cell cycle-dependent activity of the volume- and Ca2+-activated anion currents in Ehrlich lettre ascites cells

    DEFF Research Database (Denmark)

    Klausen, Thomas Kjaer; Bergdahl, Andreas; Christophersen, Palle

    2007-01-01

    Recent evidence implicates the volume-regulated anion current (VRAC) and other anion currents in control or modulation of cell cycle progression; however, the precise involvement of anion channels in this process is unclear. Here, Cl- currents in Ehrlich Lettre Ascites (ELA) cells were monitored...... during cell cycle progression, under three conditions: (i) after osmotic swelling (i.e., VRAC), (ii) after an increase in the free intracellular Ca2+ concentration (i.e., the Ca2+-activated Cl- current, CaCC), and (iii) under steady-state isotonic conditions. The maximal swelling-activated VRAC current......+ in the pipette), was unaltered from G0 to G1, but decreased in early S phase. A novel high-affinity anion channel inhibitor, the acidic di-aryl-urea NS3728, which inhibited both VRAC and CaCC, attenuated ELA cell growth, suggesting a possible mechanistic link between cell cycle progression and cell cycle...

  16. Automatic Bayes Factors for Testing Equality- and Inequality-Constrained Hypotheses on Variances.

    Science.gov (United States)

    Böing-Messing, Florian; Mulder, Joris

    2018-05-03

    In comparing characteristics of independent populations, researchers frequently expect a certain structure of the population variances. These expectations can be formulated as hypotheses with equality and/or inequality constraints on the variances. In this article, we consider the Bayes factor for testing such (in)equality-constrained hypotheses on variances. Application of Bayes factors requires specification of a prior under every hypothesis to be tested. However, specifying subjective priors for variances based on prior information is a difficult task. We therefore consider so-called automatic or default Bayes factors. These methods avoid the need for the user to specify priors by using information from the sample data. We present three automatic Bayes factors for testing variances. The first is a Bayes factor with equal priors on all variances, where the priors are specified automatically using a small share of the information in the sample data. The second is the fractional Bayes factor, where a fraction of the likelihood is used for automatic prior specification. The third is an adjustment of the fractional Bayes factor such that the parsimony of inequality-constrained hypotheses is properly taken into account. The Bayes factors are evaluated by investigating different properties such as information consistency and large sample consistency. Based on this evaluation, it is concluded that the adjusted fractional Bayes factor is generally recommendable for testing equality- and inequality-constrained hypotheses on variances.

  17. Single-current-sensor-based active front-end-converter-fed four ...

    Indian Academy of Sciences (India)

    Joseph Kiran Banda

    Keywords. Field-oriented control; vector control of induction motor; active front end converter; power factor correction .... sinusoidal three-phase input currents applied to the stator. ... with necessary feed-forward terms are employed to control.

  18. DSP based adaptive hysteresis-band current controlled active filter ...

    African Journals Online (AJOL)

    The use of non-linear loads critically affects the quality of supply by drawing harmonic currents and reactive power from the electrical distribution system. Active power filters are the most viable solution for solving such power quality problems in compliance with the harmonic standards. This article presents a digital signal ...

  19. Effects of current physical activity on affective response to exercise: physical and social-cognitive mechanisms.

    Science.gov (United States)

    Magnan, Renee E; Kwan, Bethany M; Bryan, Angela D

    2013-01-01

    Affective responses during exercise are often important determinants of exercise initiation and maintenance. Current physical activity may be one individual difference that is associated with the degree to which individuals have positive (or negative) affective experiences during exercise. The objective of this study was to explore physical and cognitive explanations of the relationship between current activity status (more versus less active) and affective response during a 30-minute bout of moderate-intensity exercise. Participants reported their current level of physical activity, exercise self-efficacy and affect during a 30-minute bout of moderate-intensity exercise. More active individuals experienced higher levels of positive affect and tranquillity and lower levels of negative affect and fatigue during exercise. Multivariate models for each affective state indicated separate processes through which physical activity may be associated with changes in affect during exercise. These models indicate that affect experienced during physical activity is related to the current activity level and these relationships can be partially explained by the physical and cognitive factors explored in this study. Recommendations for future research to elucidate whether positive affective response to physical activity improves as a function of becoming more active over time are discussed.

  20. How do trees die? A test of the hydraulic failure and carbon starvation hypotheses

    Science.gov (United States)

    Sevanto, Sanna; Mcdowell, Nate G; Dickman, L Turin; Pangle, Robert; Pockman, William T

    2014-01-01

    Despite decades of research on plant drought tolerance, the physiological mechanisms by which trees succumb to drought are still under debate. We report results from an experiment designed to separate and test the current leading hypotheses of tree mortality. We show that piñon pine (Pinus edulis) trees can die of both hydraulic failure and carbon starvation, and that during drought, the loss of conductivity and carbohydrate reserves can also co-occur. Hydraulic constraints on plant carbohydrate use determined survival time: turgor loss in the phloem limited access to carbohydrate reserves, but hydraulic control of respiration prolonged survival. Our data also demonstrate that hydraulic failure may be associated with loss of adequate tissue carbohydrate content required for osmoregulation, which then promotes failure to maintain hydraulic integrity. PMID:23730972

  1. Muscarinic activation of Ca2+-activated Cl− current in interstitial cells of Cajal

    Science.gov (United States)

    Zhu, Mei Hong; Sung, In Kyung; Zheng, Haifeng; Sung, Tae Sik; Britton, Fiona C; O'Driscoll, Kate; Koh, Sang Don; Sanders, Kenton M

    2011-01-01

    Abstract Interstitial cells of Cajal (ICC) provide pacemaker activity and functional bridges between enteric motor nerve terminals and gastrointestinal smooth muscle cells. The ionic conductance(s) in ICC that are activated by excitatory neural inputs are unknown. Transgenic mice (KitcopGFP/+) with constitutive expression of a bright green fluorescent protein were used to investigate cellular responses of ICC to cholinergic stimulation. ICC displayed spontaneous transient inward currents (STICs) under voltage clamp that corresponded to spontaneous transient depolarizations (STDs) under current clamp. STICs reversed at 0 mV when ECl = 0 mV and at –40 mV when ECl was –40 mV, suggesting the STICs were due to a chloride conductance. Carbachol (CCh, 100 nm and 1 μm) induced a sustained inward current (depolarization in current clamp) and increased the amplitude and frequency of STICs and STDs. CCh responses were blocked by atropine (10 μm) or 4-DAMP (100 nm), an M3 receptor antagonist. STDs were blocked by niflumic acid and 5-nitro-2-(3-phenylpropylamino)-benzoic acid (both 100 μm), and CCh had no effect in the presence of these drugs. The responses of intact circular muscles to CCh and stimulation of intrinsic excitatory nerves by electrical field stimulation (EFS) were also compared. CCh (1 μm) caused atropine-sensitive depolarization and increased the maximum depolarization of slow waves. Similar atropine-sensitive responses were elicited by stimulation of intrinsic excitatory neurons. Niflumic acid (100 μm) blocked responses to EFS but had minor effect on responses to exogenous CCh. These data suggest that different ionic conductances are responsible for electrical responses elicited by bath-applied CCh and cholinergic nerve stimulation. PMID:21768263

  2. Evolution of microgastropods (Ellobioidea, Carychiidae): integrating taxonomic, phylogenetic and evolutionary hypotheses

    Science.gov (United States)

    2013-01-01

    Background Current biodiversity patterns are considered largely the result of past climatic and tectonic changes. In an integrative approach, we combine taxonomic and phylogenetic hypotheses to analyze temporal and geographic diversification of epigean (Carychium) and subterranean (Zospeum) evolutionary lineages in Carychiidae (Eupulmonata, Ellobioidea). We explicitly test three hypotheses: 1) morphospecies encompass unrecognized evolutionary lineages, 2) limited dispersal results in a close genetic relationship of geographical proximally distributed taxa and 3) major climatic and tectonic events had an impact on lineage diversification within Carychiidae. Results Initial morphospecies assignments were investigated by different molecular delimitation approaches (threshold, ABGD, GMYC and SP). Despite a conservative delimitation strategy, carychiid morphospecies comprise a great number of unrecognized evolutionary lineages. We attribute this phenomenon to historic underestimation of morphological stasis and phenotypic variability amongst lineages. The first molecular phylogenetic hypothesis for the Carychiidae (based on COI, 16S and H3) reveals Carychium and Zospeum to be reciprocally monophyletic. Geographical proximally distributed lineages are often closely related. The temporal diversification of Carychiidae is best described by a constant rate model of diversification. The evolution of Carychiidae is characterized by relatively few (long distance) colonization events. We find support for an Asian origin of Carychium. Zospeum may have arrived in Europe before extant members of Carychium. Distantly related Carychium clades inhabit a wide spectrum of the available bioclimatic niche and demonstrate considerable niche overlap. Conclusions Carychiid taxonomy is in dire need of revision. An inferred wide distribution and variable phenotype suggest underestimated diversity in Zospeum. Several Carychium morphospecies are results of past taxonomic lumping. By collecting

  3. Current Activities of the Joint Council on Economic Education.

    Science.gov (United States)

    Highsmith, Robert J.

    1987-01-01

    Reviews current activities of the Joint Council, among them, a researcher training institute, a new K-12 economic education scope and sequence document, a junior high level test of economic knowledge, an instructional package for advanced placement classes, a textbook conference, a project to help teachers of students who work with at-risk…

  4. Reduced Sodium Current in the Lateral Ventricular Wall Induces Inferolateral J-Waves.

    Science.gov (United States)

    Meijborg, Veronique M F; Potse, Mark; Conrath, Chantal E; Belterman, Charly N W; De Bakker, Jacques M T; Coronel, Ruben

    2016-01-01

    J-waves in inferolateral leads are associated with a higher risk for idiopathic ventricular fibrillation. We aimed to test potential mechanisms (depolarization or repolarization dependent) responsible for inferolateral J-waves. We hypothesized that inferolateral J-waves can be caused by regional delayed activation of myocardium that is activated late during normal conditions. Computer simulations were performed to evaluate how J-point elevation is influenced by reducing sodium current conductivity (GNa), increasing transient outward current conductivity (Gto), or cellular uncoupling in three predefined ventricular regions (lateral, anterior, or septal). Two pig hearts were Langendorff-perfused with selective perfusion with a sodium channel blocker of lateral or anterior/septal regions. Volume-conducted pseudo-electrocardiograms (ECG) were recorded to detect the presence of J-waves. Epicardial unipolar electrograms were simultaneously recorded to obtain activation times (AT). Simulation data showed that conduction slowing, caused by reduced sodium current, in lateral, but not in other regions induced inferolateral J-waves. An increase in transient outward potassium current or cellular uncoupling in the lateral zone elicited slight J-point elevations which did not meet J-wave criteria. Additional conduction slowing in the entire heart attenuated J-waves and J-point elevations on the ECG, because of masking by the QRS. Experimental data confirmed that conduction slowing attributed to sodium channel blockade in the left lateral but not in the anterior/septal ventricular region induced inferolateral J-waves. J-waves coincided with the delayed activation. Reduced sodium current in the left lateral ventricular myocardium can cause inferolateral J-waves on the ECG.

  5. Interleaved Buck Converter with Variable Number of Active Phases and a Predictive Current Sharing Scheme

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes; Garcia, O.; Oliver, J. A.

    2008-01-01

    The efficiency of an interleaved Buck converter is typically low at light load conditions because of the switching losses in each of the switching stages. Improvements in the converter efficiency can be achieved by dynamically changing the number of active phases depending on the load current....... This paper addresses the issues related to the transient response of the converter when the number of active phases is changed by a digital control scheme. The problem arises because the current in the individual phases of the interleaved Buck converter will not be equal immediately after the controller has...... changed the number of active phases. This paper proposes a current equalisation scheme that adjusts the duty cycle of each phase in a manner that ensures equal average inductor current in all active phases in one or two PWM periods. The current equalisation scheme relies on the measurement of the output...

  6. How and when do expert emergency physicians generate and evaluate diagnostic hypotheses? A qualitative study using head-mounted video cued-recall interviews.

    Science.gov (United States)

    Pelaccia, Thierry; Tardif, Jacques; Triby, Emmanuel; Ammirati, Christine; Bertrand, Catherine; Dory, Valérie; Charlin, Bernard

    2014-12-01

    The ability to make a diagnosis is a crucial skill in emergency medicine. Little is known about the way emergency physicians reach a diagnosis. This study aims to identify how and when, during the initial patient examination, emergency physicians generate and evaluate diagnostic hypotheses. We carried out a qualitative research project based on semistructured interviews with emergency physicians. The interviews concerned management of an emergency situation during routine medical practice. They were associated with viewing the video recording of emergency situations filmed in an "own-point-of-view" perspective. The emergency physicians generated an average of 5 diagnostic hypotheses. Most of these hypotheses were generated before meeting the patient or within the first 5 minutes of the meeting. The hypotheses were then rank ordered within the context of a verification procedure based on identifying key information. These tasks were usually accomplished without conscious effort. No hypothesis was completely confirmed or refuted until the results of investigations were available. The generation and rank ordering of diagnostic hypotheses is based on the activation of cognitive processes, enabling expert emergency physicians to process environmental information and link it to past experiences. The physicians seemed to strive to avoid the risk of error by remaining aware of the possibility of alternative hypotheses as long as they did not have the results of investigations. Understanding the diagnostic process used by emergency physicians provides interesting ideas for training residents in a specialty in which the prevalence of reasoning errors leading to incorrect diagnoses is high. Copyright © 2014 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

  7. Development of a patient-reported outcome measure of recovery after abdominal surgery: a hypothesized conceptual framework.

    Science.gov (United States)

    Alam, Roshni; Figueiredo, Sabrina M; Balvardi, Saba; Nauche, Bénédicte; Landry, Tara; Lee, Lawrence; Mayo, Nancy E; Feldman, Liane S; Fiore, Julio F

    2018-05-17

    We initiated a research program to develop a novel patient-reported outcome measure (PROM) to assess postoperative recovery from the perspective of abdominal surgery patients. In light of FDA recommendations, the first stage of our program aimed to, based on previous literature and expert input, develop a hypothesized conceptual framework portraying the health domains that are potentially relevant to the process of recovery after abdominal surgery. This study was conducted in three phases: (1) systematic review to identify PROMs with measurement properties appraised in the context of recovery after abdominal surgery, (2) content analysis to categorize the health domains covered by the PROMs according to the ICF, and (3) two-round Delphi study to gain expert input regarding which of these health domains are relevant to the process of recovery. Participants were experts in perioperative care identified through two major surgical societies (35 invited). The systematic review identified 19 PROMs covering 66 ICF domains. 23 experts (66%) participated in the Delphi process. After Round 2, experts agreed that 22 health domains (8 body functions, 14 activities and participation) are potentially relevant to the process of recovery after abdominal surgery. These domains were organized into a diagram, representing our hypothesized conceptual framework. This hypothesized conceptual framework is an important first step in our research program and will be further refined based on in-depth qualitative interviews with patients. The sound methodological approach used to derive this framework may be valuable for studies aimed to develop PROMs according to FDA standards.

  8. Comparison for aphasic and control subjects of eye movements hypothesized in neurolinguistic programming.

    Science.gov (United States)

    Dooley, K O; Farmer, A

    1988-08-01

    Neurolinguistic programming's hypothesized eye movements were measured independently using videotapes of 10 nonfluent aphasic and 10 control subjects matched for age and sex. Chi-squared analysis indicated that eye-position responses were significantly different for the groups. Although earlier research has not supported the hypothesized eye positions for normal subjects, the present findings support the contention that eye-position responses may differ between neurologically normal and aphasic individuals.

  9. A Novel Sliding Mode Control Technique for Indirect Current Controlled Active Power Filter

    Directory of Open Access Journals (Sweden)

    Juntao Fei

    2012-01-01

    Full Text Available A novel sliding mode control (SMC method for indirect current controlled three-phase parallel active power filter is presented in this paper. There are two designed closed loops in the system: one is the DC voltage controlling loop and the other is the reference current tracking loop. The first loop with a PI regulator is used to control the DC voltage approximating to the given voltage of capacitor, and the output of PI regulator through a low-pass filter is applied as the input of the power supply reference currents. The second loop implements the tracking of the reference currents using integral sliding mode controller, which can improve the harmonic treating performance. Compared with the direct current control technique, it is convenient to be implemented with digital signal processing system because of simpler system structure and better harmonic treating property. Simulation results verify that the generated reference currents have the same amplitude with the load currents, demonstrating the superior harmonic compensating effects with the proposed shunt active power filter compared with the hysteresis method.

  10. A linear combination of pharmacophore hypotheses as a new tool in search of new active compounds--an application for 5-HT1A receptor ligands.

    Directory of Open Access Journals (Sweden)

    Dawid Warszycki

    Full Text Available This study explores a new approach to pharmacophore screening involving the use of an optimized linear combination of models instead of a single hypothesis. The implementation and evaluation of the developed methodology are performed for a complete known chemical space of 5-HT1AR ligands (3616 active compounds with K i < 100 nM acquired from the ChEMBL database. Clusters generated from three different methods were the basis for the individual pharmacophore hypotheses, which were assembled into optimal combinations to maximize the different coefficients, namely, MCC, accuracy and recall, to measure the screening performance. Various factors that influence filtering efficiency, including clustering methods, the composition of test sets (random, the most diverse and cluster population-dependent and hit mode (the compound must fit at least one or two models from a final combination were investigated. This method outmatched both single hypothesis and random linear combination approaches.

  11. Risk, innovation, electricity infrastructure and construction cost overruns: Testing six hypotheses

    International Nuclear Information System (INIS)

    Sovacool, Benjamin K.; Gilbert, Alex; Nugent, Daniel

    2014-01-01

    This study investigates the frequency and magnitude of cost and time overruns occurring during the construction of 401 electricity projects built between 1936 and 2014 in 57 countries. In aggregate, these projects required approximately $820 billion in investment, and amounted to 325,515 MW of installed capacity and 8495 km of transmission lines. We use this sample of projects to test six hypotheses about construction cost overruns related to (1) diseconomies of scale, (2) project delays, (3) technological learning, (4) regulation and markets, (5) decentralization and modularity, and (6) normalization of results to scale. We find that nuclear reactors are the riskiest technology in terms of mean cost escalation as a percentage of budget and frequency; that hydroelectric dams stand apart for their mean cost escalation in total dollars; that many of the hypotheses grounded in the literature appear wrong; and that financing, partnerships, modularity, and accountability may have more to do with overruns than technology. - Highlights: • Many hypotheses about construction overruns grounded in the literature appear wrong. • Nuclear reactors are the most prone to cost overruns as a percentage of budget and frequency. • Hydroelectric dams stand apart for their mean cost escalation in total dollars. • Solar and wind energy systems are least at risk to cost overruns

  12. Experienced physicians benefit from analyzing initial diagnostic hypotheses

    Science.gov (United States)

    Bass, Adam; Geddes, Colin; Wright, Bruce; Coderre, Sylvain; Rikers, Remy; McLaughlin, Kevin

    2013-01-01

    Background Most incorrect diagnoses involve at least one cognitive error, of which premature closure is the most prevalent. While metacognitive strategies can mitigate premature closure in inexperienced learners, these are rarely studied in experienced physicians. Our objective here was to evaluate the effect of analytic information processing on diagnostic performance of nephrologists and nephrology residents. Methods We asked nine nephrologists and six nephrology residents at the University of Calgary and Glasgow University to diagnose ten nephrology cases. We provided presenting features along with contextual information, after which we asked for an initial diagnosis. We then primed participants to use either hypothetico-deductive reasoning or scheme-inductive reasoning to analyze the remaining case data and generate a final diagnosis. Results After analyzing initial hypotheses, both nephrologists and residents improved the accuracy of final diagnoses (31.1% vs. 65.6%, p inductive reasoning (odds ratio [95% confidence interval] 5.69 [1.59, 20.33], p = 0.07), whereas the performance of experienced nephrologists did not differ between strategies (odds ratio 0.57 [0.23, 1.39], p = 0.20). Discussion Experienced nephrologists and nephrology residents can improve their performance by analyzing initial diagnostic hypotheses. The explanation of the interaction between experience and the effect of different reasoning strategies is unclear, but may relate to preferences in reasoning strategy, or the changes in knowledge structure with experience. PMID:26451203

  13. Kolmogorov's refined similarity hypotheses for turbulence and general stochastic processes

    International Nuclear Information System (INIS)

    Stolovitzky, G.; Sreenivasan, K.R.

    1994-01-01

    Kolmogorov's refined similarity hypotheses are shown to hold true for a variety of stochastic processes besides high-Reynolds-number turbulent flows, for which they were originally proposed. In particular, just as hypothesized for turbulence, there exists a variable V whose probability density function attains a universal form. Analytical expressions for the probability density function of V are obtained for Brownian motion as well as for the general case of fractional Brownian motion---the latter under some mild assumptions justified a posteriori. The properties of V for the case of antipersistent fractional Brownian motion with the Hurst exponent of 1/3 are similar in many details to those of high-Reynolds-number turbulence in atmospheric boundary layers a few meters above the ground. The one conspicuous difference between turbulence and the antipersistent fractional Brownian motion is that the latter does not possess the required skewness. Broad implications of these results are discussed

  14. Constant conditional entropy and related hypotheses

    International Nuclear Information System (INIS)

    Ferrer-i-Cancho, Ramon; Dębowski, Łukasz; Moscoso del Prado Martín, Fermín

    2013-01-01

    Constant entropy rate (conditional entropies must remain constant as the sequence length increases) and uniform information density (conditional probabilities must remain constant as the sequence length increases) are two information theoretic principles that are argued to underlie a wide range of linguistic phenomena. Here we revise the predictions of these principles in the light of Hilberg’s law on the scaling of conditional entropy in language and related laws. We show that constant entropy rate (CER) and two interpretations for uniform information density (UID), full UID and strong UID, are inconsistent with these laws. Strong UID implies CER but the reverse is not true. Full UID, a particular case of UID, leads to costly uncorrelated sequences that are totally unrealistic. We conclude that CER and its particular cases are incomplete hypotheses about the scaling of conditional entropies. (letter)

  15. A set working hypotheses towards a unified view of the universe

    International Nuclear Information System (INIS)

    Kecher, J.-C.; Vigier, J.P.; Centre National de la Recherche Scientifique, 75 - Paris; Paris-6 Univ., 75

    1976-01-01

    Some observation evidence (anisotropy and inhomogeneity of the Hubble constant, abnormal red shifts) led the authors to formulate working hypotheses compatible with these observations. The logics of these hypotheses led to consider the universe as a ''hierarchical'' universe similar to Charlier one, and to find the cause of the apparent expansion in the interactions affecting the path of the photons. As, in some cases, intrinsic red shifts are very important this reduces the distance of the considered objects and their absolute luminosity, and forces to link them with ordinary galaxies; a scheme of evolution of extragalactic objects is suggested, to account for the geometrical location of abnormal objects, and for some aspects of their morphology. Coherent picture of the universe might emerge from the suggested studies

  16. Current status of research and related activities in NAA application

    International Nuclear Information System (INIS)

    Ab Khalik bin Haji Wood

    1999-01-01

    Current activities of Analytical Chemistry Group of MINT (Malaysia Institute for Nuclear Technology Research) laboratory for elemental analysis of trace amounts in environmental samples such as air particulate matter (on air filter), soils/sediments, water, flora/fauna, oil sludge/waste sludge, and tailing/blasting slag and others, utilizing particularly NAA (Neutron Activation Analysis) method are reviewed. The laboratory participates in the IAEA-organized Interlaboratory Comparison Studies to ensure the analytical system. Other activities include analytical chemistry services with ICP-mass spectrometry and GC/GCMS to compliment the NAA and, moreover, air and marine pollution studies with participation in the UNDP/RCA/IAEA project. (S. Ohno)

  17. Active superconducting DC fault current limiter based on flux compensation

    International Nuclear Information System (INIS)

    Shi Jing; Tang Yuejin; Wang, Chen; Zhou Yusheng; Li Jingdong; Ren Li; Chen Shijie

    2006-01-01

    With the extensive application of DC power systems, suppression of DC fault current is an important subject that guarantees system security. This paper presents an active superconducting DC fault current limiter (DC-SFCL) based on flux compensation. The DC-SFCL is composed of two superconducting windings wound on a single iron core, the primary winding is in series with DC power system, and the second winding is connected with AC power system through a PWM converter. In normal operating state, the flux in the iron core is compensated to zero, and the SFCL has no influence on DC power system. In the case of DC system accident, through regulating the active power exchange between the SFCL's second winding and the AC power system, the current on the DC side can be limited to different level complying with the system demand. Moreover, the PWM converter that interface the DC system and AC system can be controlled as a reactive power source to supply voltage support for the AC side, which has little influence on the performance of SFCL. Using MATLAB SIMULINK, the mathematic model of the DC-SFCL is created, simulation results validate the dynamics of system, and the performance of DC-SFCL is confirmed

  18. Development of working hypotheses linking management of the Missouri River to population dynamics of Scaphirhynchus albus (pallid sturgeon)

    Science.gov (United States)

    Jacobson, Robert B.; Parsley, Michael J.; Annis, Mandy L.; Colvin, Michael E.; Welker, Timothy L.; James, Daniel A.

    2016-01-20

    This report documents a process of filtering of hypotheses that relate Missouri River Scaphirhynchus albus (pallid sturgeon) population dynamics to management actions including flow alterations, channel reconfigurations, and pallid sturgeon population augmentation. The filtering process was a partnership among U.S. Geological Survey, U.S. Army Corps of Engineers, and U.S. Fish and Wildlife Service to contribute to the Missouri River Recovery Management Plan process. The objective of the filtering process was to produce a set of hypotheses with high relevance to pallid sturgeon population dynamics and decision making on the Missouri River. The Missouri River Pallid Sturgeon Effects Analysis team filtered hundreds of potential hypotheses implicit in conceptual ecological models to develop a set of 40 candidate dominant hypotheses that were identified by experts as being important in pallid sturgeon population dynamics. Using a modified Delphi process and additional expert opinion, the team reduced this set of hypotheses to 23 working dominant hypotheses. We then matched the 23 hypotheses with management actions that could influence the biotic outcomes, resulting in as many as 176 potential effects between management actions and pallid sturgeon in the Missouri River. This number was consolidated to a candidate set of 53 working management hypotheses because some management actions applied to multiple life stages of the pallid sturgeon. We used an additional round of expert surveys to identify a set of 30 working management hypotheses. Finally, the set of working management hypotheses was filtered by the U.S. Army Corps of Engineers, Missouri River Recovery Program for actions that were within the agency’s authority and jurisdiction. This round resulted in a set of 21 hypotheses for initial modeling of linkages from management to pallid sturgeon population responses.

  19. Axonal and glial currents activated during the post-tetanic hyperpolarization in non-myelinated nerve.

    Science.gov (United States)

    Robert, A; Jirounek, P

    1998-07-01

    Changes in membrane potential and potassium concentration in the extracellular space ([K+]e) of rabbit vagus nerve were measured simultaneously during electrical activity and during the period of recovery using a modified sucrose-gap method and potassium-sensitive microelectrodes. After stimulation for 15 s at 15 Hz the main activity-induced increase in [K+]e reached 16.9 mM. This increase in [K+]e was paralleled by a depolarization of the preparation. The period of activity was followed by a post-tetanic hyperpolarization (PTH) lasting tens of seconds, generated by the axonal electrogenic Na+-K+ pump and to a lesser extent by the pump of the surrounding Schwann cells. The amplitude of the PTH dramatically increased in experiments in which inward currents were blocked by removal of Cl– or after application of Cs+ or Ba2+, indicating that under normal conditions the current generated by the Na+-K+ pump is strongly short-circuited. A pharmacological and kinetic study showed that these currents are: (1) the hyperpolarization-activated current I h, and (2) the inwardly rectifying I KIR current. The results show that the latter originates from Schwann cells. Our data indicate that in non-myelinated nerves there is a subtle association of inward ionic channels which (1) helps the cell to maintain an optimal membrane potential after a period of activity, and (2) contributes to the removal of excess K+ from the extracellular space.

  20. Assessing hypotheses about nesting site occupancy dynamics

    Science.gov (United States)

    Bled, Florent; Royle, J. Andrew; Cam, Emmanuelle

    2011-01-01

    Hypotheses about habitat selection developed in the evolutionary ecology framework assume that individuals, under some conditions, select breeding habitat based on expected fitness in different habitat. The relationship between habitat quality and fitness may be reflected by breeding success of individuals, which may in turn be used to assess habitat quality. Habitat quality may also be assessed via local density: if high-quality sites are preferentially used, high density may reflect high-quality habitat. Here we assessed whether site occupancy dynamics vary with site surrogates for habitat quality. We modeled nest site use probability in a seabird subcolony (the Black-legged Kittiwake, Rissa tridactyla) over a 20-year period. We estimated site persistence (an occupied site remains occupied from time t to t + 1) and colonization through two subprocesses: first colonization (site creation at the timescale of the study) and recolonization (a site is colonized again after being deserted). Our model explicitly incorporated site-specific and neighboring breeding success and conspecific density in the neighborhood. Our results provided evidence that reproductively "successful'' sites have a higher persistence probability than "unsuccessful'' ones. Analyses of site fidelity in marked birds and of survival probability showed that high site persistence predominantly reflects site fidelity, not immediate colonization by new owners after emigration or death of previous owners. There is a negative quadratic relationship between local density and persistence probability. First colonization probability decreases with density, whereas recolonization probability is constant. This highlights the importance of distinguishing initial colonization and recolonization to understand site occupancy. All dynamics varied positively with neighboring breeding success. We found evidence of a positive interaction between site-specific and neighboring breeding success. We addressed local

  1. Corrigendum to: Bayesian evaluation of informative hypotheses in SEM using Mplus

    NARCIS (Netherlands)

    van de Schoot, R.; Verhoeven, Marjolein; Hoijtink, H.

    2014-01-01

    This paper corrects: van de Schoot, R., Verhoeven, M., & Hoijtink, H. (2013). Bayesian evaluation ofinformative hypotheses in SEM using Mplus: A black bear story. EuropeanJournal of Developmental Psychology, 10, 81 –98.

  2. Apelin-13 enhances arcuate POMC neuron activity via inhibiting M-current.

    Directory of Open Access Journals (Sweden)

    Dong Kun Lee

    Full Text Available The hypothalamus is a key element of the neural circuits that control energy homeostasis. Specific neuronal populations within the hypothalamus are sensitive to a variety of homeostatic indicators such as circulating nutrient levels and hormones that signal circulating glucose and body fat content. Central injection of apelin secreted by adipose tissues regulates feeding and glucose homeostasis. However, the precise neuronal populations and cellular mechanisms involved in these physiological processes remain unclear. Here we examine the electrophysiological impact of apelin-13 on proopiomelanocortin (POMC neuron activity. Approximately half of POMC neurons examined respond to apelin-13. Apelin-13 causes a dose-dependent depolarization. This effect is abolished by the apelin (APJ receptor antagonist. POMC neurons from animals pre-treated with pertussis toxin still respond to apelin, whereas the Gβγ signaling inhibitor gallein blocks apelin-mediated depolarization. In addition, the effect of apelin is inhibited by the phospholipase C and protein kinase inhibitors. Furthermore, single-cell qPCR analysis shows that POMC neurons express the APJ receptor, PLC-β isoforms, and KCNQ subunits (2, 3 and 5 which contribute to M-type current. Apelin-13 inhibits M-current that is blocked by the KCNQ channel inhibitor. Therefore, our present data indicate that apelin activates APJ receptors, and the resultant dissociation of the Gαq heterotrimer triggers a Gβγ-dependent activation of PLC-β signaling that inhibits M-current.

  3. Possibilities for Estimating Horizontal Electrical Currents in Active Regions on the Sun

    Science.gov (United States)

    Fursyak, Yu. A.; Abramenko, V. I.

    2017-12-01

    Part of the "free" magnetic energy associated with electrical current systems in the active region (AR) is released during solar flares. This proposition is widely accepted and it has stimulated interest in detecting electrical currents in active regions. The vertical component of an electric current in the photosphere can be found by observing the transverse magnetic field. At present, however, there are no direct methods for calculating transverse electric currents based on these observations. These calculations require information on the field vector measured simultaneously at several levels in the photosphere, which has not yet been done with solar instrumentation. In this paper we examine an approach to calculating the structure of the square of the density of a transverse electrical current based on a magnetogram of the vertical component of the magnetic field in the AR. Data obtained with the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory (SDO) for the AR of NOAA AR 11283 are used. It is shown that (1) the observed variations in the magnetic field of a sunspot and the proposed estimate of the density of an annular horizontal current around the spot are consistent with Faraday's law and (2) the resulting estimates of the magnitude of the square of the density of the horizontal current {j}_{\\perp}^2 = (0.002- 0.004) A2/m4 are consistent with previously obtained values of the density of a vertical current in the photosphere. Thus, the proposed estimate is physically significant and this method can be used to estimate the density and structure of transverse electrical currents in the photosphere.

  4. Controversial hypotheses on the relationship between researcher and informant in qualitative research.

    Science.gov (United States)

    Wilde, V

    1992-02-01

    This paper addresses methodological issues that emerged unexpectedly during a qualitative study set up to explore nurses' descriptions of difficult, challenging and satisfying experiences at work. The purpose of the study had been to look for critical factors influencing nurses' perceptions of their performance in specific situations, and their labelling of each event. Ten nurses were asked to describe in detail three events; a difficult situation in which they had coped well, a difficult situation in which they would like to have coped better, and a satisfying or rewarding situation. The critical incident technique was used. Rich descriptions were obtained, tape recorded, transcribed verbatum, and analysed by constant comparative analysis, following the principles of grounded theory. Some suprising hypotheses emerged regarding the methodology of the informal interview in qualitative research. This paper addresses these hypotheses, which focus on the interaction between the researcher and informant, the role conflict facing the nurse researcher, the effect of the researcher's past experience on the interaction, the use of counselling strategies and the principle of self-disclosure. These hypotheses were incidental to the original area of study and were more exciting in their emergence because of this.

  5. Estimating the Proportion of True Null Hypotheses in Multiple Testing Problems

    Directory of Open Access Journals (Sweden)

    Oluyemi Oyeniran

    2016-01-01

    Full Text Available The problem of estimating the proportion, π0, of the true null hypotheses in a multiple testing problem is important in cases where large scale parallel hypotheses tests are performed independently. While the problem is a quantity of interest in its own right in applications, the estimate of π0 can be used for assessing or controlling an overall false discovery rate. In this article, we develop an innovative nonparametric maximum likelihood approach to estimate π0. The nonparametric likelihood is proposed to be restricted to multinomial models and an EM algorithm is also developed to approximate the estimate of π0. Simulation studies show that the proposed method outperforms other existing methods. Using experimental microarray datasets, we demonstrate that the new method provides satisfactory estimate in practice.

  6. Individual differences in learning correlate with modulation of brain activity induced by transcranial direct current stimulation

    Science.gov (United States)

    Falcone, Brian; Wada, Atsushi; Parasuraman, Raja

    2018-01-01

    Transcranial direct current stimulation (tDCS) has been shown to enhance cognitive performance on a variety of tasks. It is hypothesized that tDCS enhances performance by affecting task related cortical excitability changes in networks underlying or connected to the site of stimulation facilitating long term potentiation. However, many recent studies have called into question the reliability and efficacy of tDCS to induce modulatory changes in brain activity. In this study, our goal is to investigate the individual differences in tDCS induced modulatory effects on brain activity related to the degree of enhancement in performance, providing insight into this lack of reliability. In accomplishing this goal, we used functional magnetic resonance imaging (fMRI) concurrently with tDCS stimulation (1 mA, 30 minutes duration) using a visual search task simulating real world conditions. The experiment consisted of three fMRI sessions: pre-training (no performance feedback), training (performance feedback which included response accuracy and target location and either real tDCS or sham stimulation given), and post-training (no performance feedback). The right posterior parietal cortex was selected as the site of anodal tDCS based on its known role in visual search and spatial attention processing. Our results identified a region in the right precentral gyrus, known to be involved with visual spatial attention and orienting, that showed tDCS induced task related changes in cortical excitability that were associated with individual differences in improved performance. This same region showed greater activity during the training session for target feedback of incorrect (target-error feedback) over correct trials for the tDCS stim over sham group indicating greater attention to target features during training feedback when trials were incorrect. These results give important insight into the nature of neural excitability induced by tDCS as it relates to variability in

  7. Recruitment processes in Baltic sprat - A re-evaluation of GLOBEC Germany hypotheses

    Science.gov (United States)

    Voss, Rüdiger; Peck, Myron A.; Hinrichsen, Hans-Harald; Clemmesen, Catriona; Baumann, Hannes; Stepputtis, Daniel; Bernreuther, Matthias; Schmidt, Jörn O.; Temming, Axel; Köster, Fritz W.

    2012-12-01

    The GLOBEC Germany program (2002-2007) had the ambitious goal to resolve the processes impacting the recruitment dynamics of Baltic sprat (Sprattus sprattus L.) by examining various factors affecting early life history stages. At the start of the research program, a number of general recruitment hypotheses were formulated, i.e. focusing on (1) predation, (2) food availability, (3) physical parameters, (4) the impact of current systems, and finally (5) the importance of top-down vs bottom-up effects. The present study synthesizes the results of field sampling (2002 and 2003), laboratory experiments, and modeling studies to re-evaluate these hypotheses for the Baltic sprat stock. Recruitment success was quite different in the 2 years investigated. Despite a lower spawning stock biomass in 2003, the total number of recruits was almost 2-fold higher that year compared to 2002. The higher recruitment success in 2003 could be attributed to enhanced survival success during the post-larval/juvenile stage, a life phase that appears to be critical for recruitment dynamics. In the state of the Baltic ecosystem during the period of investigation, we consider bottom-up control (e.g. temperature, prey abundance) to be more important than top-down control (predation mortality). This ranking in importance does not vary seasonally. Prevailing water circulation patterns and the transport dynamics of larval cohorts have a strong influence on sprat recruitment success. Pronounced transport to coastal areas is detrimental for year-class strength particularly at high sprat stock sizes. A suggested mechanism is density-dependant regulation of survival via intra- and inter-specific competition for prey in coastal areas. A documented change in larval vertical migration behavior between the early 1990s and early 2000s increased the transport potential to the coast, strengthening the coupling between inter-annual differences in the magnitude and direction of wind-driven surface currents and

  8. [A review of current studies on leisure activities performed by community-dwelling elders].

    Science.gov (United States)

    Li, Yueh-Ping; Chen, Ching-Huey

    2010-02-01

    This article reviewed and summarized the findings of previously published studies on the leisure activities of community elders over 55 years of age. A total of 17 related articles, published before 2008, were identified in the search of electronic databases, which included the Chinese Periodical Table of Contents Index Image System, CEPS, Medline and Ageline. Leisure activities measurements used in this study consisted of recoding activities either categorically or by frequency. The majority of research indicated that elderly engage in primarily static activities and that participation in leisure activities had positive effects on cognitive and psychological health. However, inconsistencies in results were found due to differences in measurement tools and sample populations used among studies, making it difficult to conduct a valid comparison of specific features of elderly leisure activities. Most current leisure activity studies utilize cross-sectional research methodologies with restricted topics, which result in limited applicability of research results. In conclusion, we suggest that future studies should develop instruments to assess leisure activities that correspond to local conditions identified through qualitative research. With such, researchers can study different age groups by applying relevant ageing theories to construct empirical data related to current elderly leisure activities.

  9. An investigation of the impact of selected prereading activities on student content learning through laboratory activities

    Science.gov (United States)

    Kass, Jesse (Shaya)

    This study investigated whether two prereading activities impacted student learning from hands-on science activities. The study was based on constructivist learning theory. Based on the work of Piaget, it was hypothesized that students who activated prior knowledge would learn more from the activities. Based on the work of Vygotsky it was hypothesized that students who talk more and write more would learn more from the activity. The K-W-L chart and anticipation guide strategies were used with eighth grade students at Graves Middle School in Whittier, California before learning about levers and convection currents. D. M. Ogle (1986) created the three-column K-W-L chart to have students activate prior knowledge. In the first column, the students write what they already know about a subject, in the second column, the students write what they want to know about the subject, and the students complete the third column after learning about a subject by writing answers to the questions that they asked in the second column. Duffelmeyer (1994) created the anticipation guide based on Herber's (1978) reasoning guide. In the anticipation guide, the teacher creates three or four sentences that convey the major ideas of the topic and the students either agree or disagree with the statements. After learning about the topic, students revisit their answers and decide if they were correct or incorrect and they must defend their choices. This research used the Solomon (1947) four-square design and compared both the experimental groups to a control group that simply discussed the concepts before completing the activity. The research showed no significant difference between the control group and either of the treatment groups. The reasons for the lack of significant differences are considered. It was hypothesized that since the students were unfamiliar with the prereading activities and did not have much experience with using either writing-to-learn or talking-to-learn strategies, the

  10. Polyphenol-Protein Complexes and Their Consequences for the Redox Activity, Structure and Function of Honey. A Current View and New Hypothesis – a Review

    Directory of Open Access Journals (Sweden)

    Brudzynski Katrina

    2015-06-01

    Full Text Available There is increasing evidence that protein complexation by honey polyphenols is changing honey structure and function. This relatively less investigated filed of honey research is presented in a context of known mechanism of formation of the stable polyphenol-protein complexes in other foods. At a core of these interactions lies the ability of polyphenols to form non-covalent and covalent bonds with proteins leading to transient and/or irreversible complexes, respectively. Honey storage and thermal processing induces non-enzymatic oxidation of polyphenols to reactive quinones and enables them to form covalent bonds with proteins. In this short review, we present data from our laboratory on previously unrecognized types of protein-polyphenol complexes that differed in size, stoichiometry, and antioxidant capacities, and the implications they have to honey antioxidant and antibacterial activities. Our intent is to provide a current understanding of protein-polyphenol complexation in honey and also some new thoughts /hypotheses that can be useful in directing future research.

  11. Modulation of membrane potential by an acetylcholine-activated potassium current in trout atrial myocytes

    DEFF Research Database (Denmark)

    Molina, C.E.; Gesser, Hans; Llach, A.

    2007-01-01

    mV from 4.3 pA/pF to 27 pA/pF with an EC50 of 45 nM in atrial myocytes. Moreover, 3 nM ACh increased the slope conductance of Im fourfold, shifted its reversal potential from -78 ± 3 to -84 ± 3 mV, and stabilized the resting membrane potential at -92 ± 4 mV. ACh also shortened the action potential...... hypothesized that this is at least partly due to a small slope conductance of Im around the resting membrane potential in atrial myocytes. In accordance with this hypothesis, the slope conductance of Im was about sevenfold smaller in atrial than in ventricular myocytes. Interestingly, ACh increased Im at -120...... of an inwardly rectifying K+ current can modulate the membrane potential in the trout atrial myocytes and stabilize the resting membrane potential. teleost heart; IK,ACh; cholinergic modulation; action potential...

  12. Support for major hypotheses in invasion biology is uneven and declining

    Czech Academy of Sciences Publication Activity Database

    Jeschke, J.M.; Aparicio, L.G.; Haider, S.; Heger, T.; Lortie, C. J.; Pyšek, Petr; Strayer, D.L.

    2012-01-01

    Roč. 2012, č. 14 (2012), s. 1-20 ISSN 1619-0033 R&D Projects: GA ČR(CZ) GAP504/11/1028 Institutional support: RVO:67985939 Keywords : biological invasions * hypotheses * testing Subject RIV: EF - Botanics

  13. Grid-Current-Feedback Active Damping for LCL Resonance in Grid-Connected Voltage-Source Converters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2016-01-01

    This paper investigates active damping of LCL-filter resonance in a grid-connected voltage-source converter with only grid-current feedback control. Basic analysis in the s-domain shows that the proposed damping technique with a negative high-pass filter along its damping path is equivalent...... of phase-lag, in turn, helps to shrink the region of nonminimum-phase behavior caused by negative virtual resistance inserted unintentionally by most digitally implemented active damping techniques. The presented high-pass-filtered active damping technique with a single grid-current feedback loop is thus...

  14. Serial Learning Process: Test of Chaining, Position, and Dual-Process Hypotheses

    Science.gov (United States)

    Giurintano, S. L.

    1973-01-01

    The chaining, position, and dual-process hypotheses of serial learning (SL) as well as serial recall, reordering, and relearning of paired-associate learning were examined to establish learning patterns. Results provide evidence for dual-process hypothesis. (DS)

  15. Use of Computational Modeling to Evaluate Hypotheses About the Molecular and Cellular Mechanisms of Bystander Effects

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yuchao; Conolly, Rory B; Andersen, Melvin E.

    2006-11-21

    This report describes the development of a computational systems biology approach to evaluate the hypotheses of molecular and cellular mechanisms of adaptive response to low dose ionizing radiation. Our concept is that computational models of signaling pathways can be developed and linked to biologically based dose response models to evaluate the underlying molecular mechanisms which lead to adaptive response. For development of quantitatively accurate, predictive models, it will be necessary to describe tissues consisting of multiple cell types where the different types each contribute in their own way to the overall function of the tissue. Such a model will probably need to incorporate not only cell type-specific data but also spatial information on the architecture of the tissue and on intercellular signaling. The scope of the current model was more limited. Data obtained in a number of different biological systems were synthesized to describe a chimeric, “average” population cell. Biochemical signaling pathways involved in sensing of DNA damage and in the activation of cell cycle checkpoint controls and the apoptotic path were also included. As with any computational modeling effort, it was necessary to develop these simplified initial descriptions (models) that can be iteratively refined. This preliminary model is a starting point which, with time, can evolve to a level of refinement where large amounts of detailed biological information are synthesized and a capability for robust predictions of dose- and time-response behaviors is obtained.

  16. Ground Return Current Behaviour in High Voltage Alternating Current Insulated Cables

    Directory of Open Access Journals (Sweden)

    Roberto Benato

    2014-12-01

    Full Text Available The knowledge of ground return current in fault occurrence plays a key role in the dimensioning of the earthing grid of substations and of cable sealing end compounds, in the computation of rise of earth potential at substation sites and in electromagnetic interference (EMI on neighbouring parallel metallic conductors (pipes, handrails, etc.. Moreover, the ground return current evaluation is also important in steady-state regime since this stray current can be responsible for EMI and also for alternating current (AC corrosion. In fault situations and under some assumptions, the ground return current value at a substation site can be computed by means of k-factors. The paper shows that these simplified and approximated approaches have a lot of limitations and only multiconductor analysis can show the ground return current behaviour along the cable (not only the two end values both in steady-state regime and in short circuit occurrence (e.g., phase-to-ground and phase-to-phase-to-ground. Multiconductor cell analysis (MCA considers the cable system in its real asymmetry without simplified and approximated hypotheses. The sensitivity of ground return current on circuit parameters (cross-bonding box resistances, substation earthing resistances, soil resistivity is presented in the paper.

  17. Review of current activities to model and measure the orbital debris environment in low-earth orbit

    Science.gov (United States)

    Reynolds, R. C.

    A very active orbital debris program is currently being pursued at the NASA/Johnson Space Center (JSC), with projects designed to better define the current environment, to project future environments, to model the processes contributing to or constraining the growth of debris in the environment, and to gather supporting data needed to improve the understanding of the orbital debris problem and the hazard it presents to spacecraft. This paper is a review of the activity being conducted at JSC, by NASA, Lockheed Engineering and Sciences Company, and other support contractors, and presents a review of current activity, results of current research, and a discussion of directions for future development.

  18. Accumulation of slowly activating delayed rectifier potassium current (IKs) in canine ventricular myocytes

    DEFF Research Database (Denmark)

    Stengl, Milan; Volders, Paul G A; Thomsen, Morten Bækgaard

    2003-01-01

    In guinea-pig ventricular myocytes, in which the deactivation of slowly activating delayed rectifier potassium current (IKs) is slow, IKs can be increased by rapid pacing as a result of incomplete deactivation and subsequent current accumulation. Whether accumulation of IKs occurs in dogs, in which...

  19. Skin Stem Cell Hypotheses and Long Term Clone Survival - Explored Using Agent-based Modelling

    OpenAIRE

    Li, X.; Upadhyay, A.K.; Bullock, A.J.; Dicolandrea, T.; Xu, J.; Binder, R.L.; Robinson, M.K.; Finlay, D.R.; Mills, K.J.; Bascom, C.C.; Kelling, C.K.; Isfort, R.J.; Haycock, J.W.; MacNeil, S.; Smallwood, R.H.

    2013-01-01

    Epithelial renewal in skin is achieved by the constant turnover and differentiation of keratinocytes. Three popular hypotheses have been proposed to explain basal keratinocyte regeneration and epidermal homeostasis: 1) asymmetric division (stem-transit amplifying cell); 2) populational asymmetry (progenitor cell with stochastic fate); and 3) populational asymmetry with stem cells. In this study, we investigated lineage dynamics using these hypotheses with a 3D agent-based model of the epiderm...

  20. Volunteering and overseas placements in the NHS: a survey of current activity.

    Science.gov (United States)

    Chatwin, John; Ackers, Louise

    2016-10-19

    The study aimed to establish current levels of overseas volunteering and placement activity across all staff grades within the National Health Service (NHS) in the North West of England. Cross-sectional survey. Descriptive statistics. 4 main regional hospitals in the North West of England, and additional NHS staff training events. Convenience sample of NHS staff (n=911). 911 NHS staff took part in the survey. The medical and dental staff group returned the highest number of responses (32.1%). 42% of staff reported some form of overseas volunteering or placement experience. Most staff took an international placement as students (33.6% men; 40.6% women). Medium-term placements were undertaken by 46.7% of men, and 52.5% of women. Settlement stays (ie, over 1 year) were reported by 7.6% men, and 8.3% women). The majority of respondents engaged in international placement were from the age groups incorporating 'below 25' to '41-50' (74%). Multiple placement experiences were uncommon: 2.5% of respondents reported three periods of overseas activity, and 1.5% reported four. All those with multiple placement experience came from the staff groups incorporating midwife/nurse/health visitor, and medical and dental. This survey captured a snapshot of current levels of volunteering and overseas placement activity across NHS staff grades in the North West. Owing to relatively homogenous organisational structures, findings are likely to broadly represent the position across the organisation as a whole. Although some degree of overseas placement activity is undertaken by a relatively high proportion of NHS staff, such activity is currently heavily skewed towards higher clinical staff grades. Significant numbers of allied health professionals and equivalent non-clinical cadres also report overseas experience, and we anticipate that the numbers will continue to rise if current policy initiatives gain momentum. Published by the BMJ Publishing Group Limited. For permission to use

  1. Vestigial Biological Structures: A Classroom-Applicable Test of Creationist Hypotheses

    Science.gov (United States)

    Senter, Phil; Ambrocio, Zenis; Andrade, Julia B.; Foust, Katanya K.; Gaston, Jasmine E.; Lewis, Ryshonda P.; Liniewski, Rachel M.; Ragin, Bobby A.; Robinson, Khanna L.; Stanley, Shane G.

    2015-01-01

    Lists of vestigial biological structures in biology textbooks are so short that some young-Earth creationist authors claim that scientists have lost confidence in the existence of vestigial structures and can no longer identify any verifiable ones. We tested these hypotheses with a method that is easily adapted to biology classes. We used online…

  2. Tricarbonyldichlororuthenium (II) dimer (CORM2) activates non-selective cation current in human endothelial cells independently of carbon monoxide releasing.

    Science.gov (United States)

    Dong, De-Li; Chen, Chang; Huang, Wei; Chen, Yan; Zhang, Xiao-Lan; Li, Zhe; Li, Yue; Yang, Bao-Feng

    2008-08-20

    Tricarbonyldichlororuthenium (II) dimer (CORM2) has been developed as carbon monoxide (CO) donor. We found that CORM2 activated a type of specific current which was distinct from the big-conductance Ca(2+)-activated K(+) current activated by CO in human umbilical vein endothelial cells (HUVECs). So the aim of the present study was to characterize the CORM2-induced current and to access the relation with CO releasing. CORM2 (100 microM) activated a kind of bi-directional current in HUVECs when the ramp protocol (holding potential 0 mV, from -120 mV to +120 mV) was applied. The current was not blocked by apamin, TRAM-34 and iberiotoxin, the small, intermediate and big-conductance Ca(2+) -activated K(+) channel blockers, and it was not sensitive to the pipette solution chelated with EGTA. CORM2 still activated the current when the chloride in the pipette solution was substituted by equal mol gluconic acid. Substitution of the sodium in the bath with choline significantly reduced the current activated by CORM2. The current was regarded as the non-selective cation current. The current showed slightly inward rectifier property and was not sensitive to Gd(3+) (100 microM), La(3+) (10 microM) or 2-aminoethoxydiphenyl borate (100 microM). CO (10 microM), CORM3 (100, 200 microM) and RuCl(3) (100 microM) were used as controls and showed no effect of the current activation. In conclusion, CORM2 activated the non-selective cation current in HUVECs independently of its CO releasing.

  3. Political Participation Online: The Replacement and the Mobilisation Hypotheses Revisited

    DEFF Research Database (Denmark)

    Jensen, Jakob Linaa

    2013-01-01

    This article discusses the state of political participation online more than ten years after the Internet’s great popular breakthrough as an everyday medium. Denmark is used as a case study to critically re-examine the frequently discussed replacement and mobilisation hypotheses on behalf of the ...... participation, efficacy and social capital seem to have less impact on online political participation. In the end, these findings are related to more overall discussions on the democratising potential of the Internet.......This article discusses the state of political participation online more than ten years after the Internet’s great popular breakthrough as an everyday medium. Denmark is used as a case study to critically re-examine the frequently discussed replacement and mobilisation hypotheses on behalf...... of the Internet. The pure replacement hypothesis is rejected. Instead, it is found that the Internet still supplements rather than replaces other media, even among heavy Internet users. The Internet is one among several media used by ‘media omnivores’, and political participation online supplements rather than...

  4. Dysfunctional amygdala activation and connectivity with the prefrontal cortex in current cocaine users

    NARCIS (Netherlands)

    Crunelle, C.L.; Kaag, A.M.; van den Munkhof, H.E.; Reneman, L.; Homberg, J.R.; Sabbe, B.; van den Brink, W.; van Wingen, G.

    2015-01-01

    OBJECTIVES: Stimulant use is associated with increased anxiety and a single administration of dexamphetamine increases amygdala activation to biologically salient stimuli in healthy individuals. Here, we investigate how current cocaine use affects amygdala activity and amygdala connectivity with the

  5. Dysfunctional amygdala activation and connectivity with the prefrontal cortex in current cocaine users

    NARCIS (Netherlands)

    Crunelle, Cleo L.; Kaag, Anne Marije; van den Munkhof, Hanna E.; Reneman, Liesbeth; Homberg, Judith R.; Sabbe, Bernard; van den Brink, Wim; van Wingen, Guido

    2015-01-01

    Stimulant use is associated with increased anxiety and a single administration of dexamphetamine increases amygdala activation to biologically salient stimuli in healthy individuals. Here, we investigate how current cocaine use affects amygdala activity and amygdala connectivity with the prefrontal

  6. Pickles and ice cream! Food cravings in pregnancy: hypotheses, preliminary evidence, and directions for future research

    Science.gov (United States)

    Orloff, Natalia C.; Hormes, Julia M.

    2014-01-01

    Women in the United States experience an increase in food cravings at two specific times during their life, (1) perimenstrually and (2) prenatally. The prevalence of excess gestational weight gain (GWG) is a growing concern due to its association with adverse health outcomes in both mothers and children. To the extent that prenatal food cravings may be a determinant of energy intake in pregnancy, a better understanding of craving etiology could be crucial in addressing the issue of excessive GWG. This paper reviews the available literature to corroborate and/or dispute some of the most commonly accepted hypotheses regarding the causes of food cravings during pregnancy, including a role of (1) hormonal changes, (2) nutritional deficits, (3) pharmacologically active ingredients in the desired foods, and (4) cultural and psychosocial factors. An existing model of perimenstrual chocolate craving etiology serves to structure the discussion of these hypotheses. The main hypotheses discussed receive little support, with the notable exception of a postulated role of cultural and psychosocial factors. The presence of cravings during pregnancy is a common phenomenon across different cultures, but the types of foods desired and the adverse impact of cravings on health may be culture-specific. Various psychosocial factors appear to correlate with excess GWG, including the presence of restrained eating. Findings strongly suggest that more research be conducted in this area. We propose that future investigations fall into one of the four following categories: (1) validation of food craving and eating-related measures specifically in pregnant populations, (2) use of ecological momentary assessment to obtain real time data on cravings during pregnancy, (3) implementation of longitudinal studies to address causality between eating disorder symptoms, food cravings, and GWG, and (4) development of interventions to ensure proper prenatal nutrition and prevent excess GWG. PMID:25295023

  7. Pickles and Ice Cream! Food Cravings in Pregnancy: Hypotheses, Preliminary Evidence, and Directions for Future Research

    Directory of Open Access Journals (Sweden)

    Natalia C. Orloff

    2014-09-01

    Full Text Available Women in the United States experience an increase in food cravings at two specific times during their life, 1 perimenstrually and 2 prenatally. The prevalence of excess gestational weight gain (GWG is a growing concern due to its association with adverse health outcomes in both mothers and children. To the extent that prenatal food cravings may be a determinant of energy intake in pregnancy, a better understanding of craving etiology could be crucial in addressing the issue of excessive GWG. This paper reviews the available literature to corroborate and/or dispute some of the most commonly accepted hypotheses regarding the causes of food cravings during pregnancy, including a role of 1 hormonal changes, 2 nutritional deficits, 3 pharmacologically active ingredients in the desired foods, and 4 cultural and psychosocial factors. An existing model of perimenstrual chocolate craving etiology serves to structure the discussion of these hypotheses. The main hypotheses discussed receive little support, with the notable exception of a postulated role of cultural and psychosocial factors. The presence of cravings during pregnancy is a common phenomenon across different cultures, but the types of foods desired and the adverse impact of cravings on health may be culture-specific. Various psychosocial factors appear to correlate with excess GWG, including the presence of restrained eating. Findings strongly suggest that more research be conducted in this area. We propose that future investigations fall into one of the four following categories: 1 validation of food craving and eating-related measures specifically in pregnant populations, 2 use of ecological momentary assessment to obtain real time data on cravings during pregnancy, 3 implementation of longitudinal studies to address causality between eating disorder symptoms, food cravings, and gestational weight gain, and 4 development of interventions to ensure proper prenatal nutrition and prevent excess

  8. Activation of the Ca2+-sensing receptors increases currents through inward rectifier K+ channels via activation of phosphatidylinositol 4-kinase.

    Science.gov (United States)

    Liu, Chung-Hung; Chang, Hsueh-Kai; Lee, Sue-Ping; Shieh, Ru-Chi

    2016-11-01

    Inward rectifier K + channels are important for maintaining normal electrical function in many cell types. The proper function of these channels requires the presence of membrane phosphoinositide 4,5-bisphosphate (PIP 2 ). Stimulation of the Ca 2+ -sensing receptor CaR, a pleiotropic G protein-coupled receptor, activates both G q/11 , which decreases PIP 2 , and phosphatidylinositol 4-kinase (PI-4-K), which, conversely, increases PIP 2 . How membrane PIP 2 levels are regulated by CaR activation and whether these changes modulate inward rectifier K + are unknown. In this study, we found that activation of CaR by the allosteric agonist, NPSR568, increased inward rectifier K + current (I K1 ) in guinea pig ventricular myocytes and currents mediated by Kir2.1 channels exogenously expressed in HEK293T cells with a similar sensitivity. Moreover, using the fluorescent PIP 2 reporter tubby-R332H-cYFP to monitor PIP 2 levels, we found that CaR activation in HEK293T cells increased membrane PIP 2 concentrations. Pharmacological studies showed that both phospholipase C (PLC) and PI-4-K are activated by CaR stimulation with the latter played a dominant role in regulating membrane PIP 2 and, thus, Kir currents. These results provide the first direct evidence that CaR activation upregulates currents through inward rectifier K + channels by accelerating PIP 2 synthesis. The regulation of I K1 plays a critical role in the stability of the electrical properties of many excitable cells, including cardiac myocytes and neurons. Further, synthetic allosteric modulators that increase CaR activity have been used to treat hyperparathyroidism, and negative CaR modulators are of potential importance in the treatment of osteoporosis. Thus, our results provide further insight into the roles played by CaR in the cardiovascular system and are potentially valuable for heart disease treatment and drug safety.

  9. Causal null hypotheses of sustained treatment strategies: What can be tested with an instrumental variable?

    Science.gov (United States)

    Swanson, Sonja A; Labrecque, Jeremy; Hernán, Miguel A

    2018-05-02

    Sometimes instrumental variable methods are used to test whether a causal effect is null rather than to estimate the magnitude of a causal effect. However, when instrumental variable methods are applied to time-varying exposures, as in many Mendelian randomization studies, it is unclear what causal null hypothesis is tested. Here, we consider different versions of causal null hypotheses for time-varying exposures, show that the instrumental variable conditions alone are insufficient to test some of them, and describe additional assumptions that can be made to test a wider range of causal null hypotheses, including both sharp and average causal null hypotheses. Implications for interpretation and reporting of instrumental variable results are discussed.

  10. Using potential performance theory to test five hypotheses about meta-attribution.

    Science.gov (United States)

    Trafimow, David; Hunt, Gayle; Rice, Stephen; Geels, Kasha

    2011-01-01

    Based on I. Kant's (1991) distinction between perfect and imperfect duties and the attribution literature pertaining to that distinction, the authors proposed and tested 5 hypotheses about meta-attribution. More specifically, violations of perfect duties have been shown to arouse both more negative affect and stronger correspondent inferences than do violations of imperfect duties (e.g., D. Trafimow, I. K. Bromgard, K. A. Finlay, & T. Ketelaar, 2005). But when it comes to making meta-attributions-that is, guessing the attributions others would make-is the affect differential an advantage or a disadvantage? In addition to the null hypothesis of no effect, the authors proposed and tested additional hypotheses about how negative affect might increase or decrease the effectiveness of people's meta-attribution strategies and how even if there is no effect on strategy effectiveness, negative affect could increase or decrease the consistencies with which these strategies could be used.

  11. Modelling and analysis of the transformer current resonance in dual active bridge converters

    DEFF Research Database (Denmark)

    Qin, Zian; Shen, Zhan; Blaabjerg, Frede

    2017-01-01

    Due to the parasitic capacitances of the transformer and inductor in Dual Active Bridge (DAB) converters, resonance happens in the transformer currents. This high frequency resonant current flowing into the full bridges will worsen their soft-switching performance and thereby reduce its efficiency....... In order to study the generation mechanism of this current resonance, the impedance of the transformer and inductor with parasitic components is modelled in this digest. Then, based on the impedance model, an approach is proposed to mitigate the current resonance. Finally, both the impedance model...

  12. Masticatory-stress hypotheses and the supraorbital region of primates.

    Science.gov (United States)

    Hylander, W L; Picq, P G; Johnson, K R

    1991-09-01

    The purpose of this study is to test various masticatory-stress hypotheses about the evolution and function of well-developed browridges of higher primates. This was done by measuring and analyzing patterns of in vivo bone strain recorded from three-element rosette strain gages bonded to the supraorbital region and to other portions of the bony face of Macaca fascicularis and Papio anubis during mastication and incision. The magnitude and direction of the principal strains recorded support Endo's hypothesis that the supraorbital region during mastication and incision is bent in the frontal plane (Endo, 1966). Our data do not, however, support his hypothesis that the supraorbital region is bent more during incision than during mastication. The data also demonstrate that overall levels of supraorbital strain are not larger in more prognathic subjects. Most importantly, the data indicate that the supraorbital region of nonhuman catarrhines is strained very little during mastication and incision. This indicates that there is much more supraorbital bone than is necessary both to counter masticatory loads and to provide an adequate safety factor to failure for these loads. This in turn suggests that the macaque and baboon browridges can be considerably reduced in size and still maintain these required structural characteristics. Thus, our experiments provide no support whatsoever for those hypotheses that directly link browridge morphology to masticatory stress (cf. Endo, 1966; Russell, 1983, 1985). A recent review of Endo's original work indicates that this latter statement is also true for humans (Picq and Hylander, 1989). We conclude, therefore, that there is no good reason to believe that enlarged browridges in living and/or fossil primates are structural adaptations to counter intense masticatory forces. The evolution of browridge morphology in primates is best explained on the basis of factors related to the position of the brain relative to the orbits (Moss and

  13. The Current Status of Classroom Inclusion Activities of Secondary Agriculture Teachers

    Science.gov (United States)

    Hoerst, Caryn M.; Whittington, M. Susie

    2009-01-01

    The current status of classroom inclusion activities among agriculture teachers in comprehensive secondary agricultural education programs in Ohio is reported. The researchers describe secondary agriculture teachers' needs related to teaching learners with special needs in inclusion classes, given legislative mandates. Specifically, the…

  14. Striatal activity is modulated by target probability.

    Science.gov (United States)

    Hon, Nicholas

    2017-06-14

    Target probability has well-known neural effects. In the brain, target probability is known to affect frontal activity, with lower probability targets producing more prefrontal activation than those that occur with higher probability. Although the effect of target probability on cortical activity is well specified, its effect on subcortical structures such as the striatum is less well understood. Here, I examined this issue and found that the striatum was highly responsive to target probability. This is consistent with its hypothesized role in the gating of salient information into higher-order task representations. The current data are interpreted in light of that fact that different components of the striatum are sensitive to different types of task-relevant information.

  15. The current implementation status of the integration of sports and physical activity into Dutch rehabilitation care

    NARCIS (Netherlands)

    Hoekstra, Femke; Hettinga, Florentina J; Alingh, Rolinde A; Duijf, Marjo; Dekker, Rienk; van der Woude, Lucas H V; van der Schans, Cees P

    PURPOSE: To describe the current status of the nationwide implementation process of a sports and physical activity stimulation programme to gain insight into how sports and physical activity were integrated into Dutch rehabilitation care. METHODS: The current implementation status of a sports and

  16. Rocket-based measurement of Birkeland currents in an active post-midnight aurora

    International Nuclear Information System (INIS)

    Coley, W.R.

    1979-01-01

    At 10:45 U.T. on March 1, 1976, an instrumented payload was launched by a Nike-Tomahawk rocket from Poker Flat, Alaska. The payload passed over auroral breakup activity that had a visual intensity of about 150 kR. An electron detector covering the 8 to 10 keV energy range observed electron precipitation while a cesium vapor vector magnetometer measured magnetic perturbations along the vehicle trajectory. From the magnetic measurements a current system consisting of horizontal electrojets and two pairs of oppositely directed field-aligned current sheets was inferred. The total current density carried by these sheets is much larger than that carried by the energetic electrons alone; hence, other particles are the primary current carriers. Data provided by the Chatanika radar facility are used along with other ground-based data to obtain electric fields conductivity estimates, and current densities, which are compared to the currents measured by the flight magnetometer. Results indicate that the ionosphere acts as an electrical load, providing the closing current for Birkeland current flow being generated out in the magnetosphere

  17. INFLUENCES ON AND FROM THE SEGMENTATION OF NETWORKS - HYPOTHESES AND TESTS

    NARCIS (Netherlands)

    BAERVELDT, C; SNIJDERS, T

    This article discusses (a) the influence of network structure on the diffusion of (new) cultural behavior within the network and (b) the influence of external events, especially of social programs, on the diffusion of (new) cultural behavior, and on the network structure. Hypotheses are formulated

  18. Editorial: hypotheses about protein folding - the proteomic code and wonderfolds

    Directory of Open Access Journals (Sweden)

    Agutter Paul S

    2009-12-01

    Full Text Available Abstract Theoretical biology journals can contribute in many ways to the progress of knowledge. They are particularly well-placed to encourage dialogue and debate about hypotheses addressing problematical areas of research. An online journal provides an especially useful forum for such debate because of the option of posting comments within days of the publication of a contentious article.

  19. Current studies of biological materials using instrumental and radiochemical neutron activation analysis

    International Nuclear Information System (INIS)

    Fardy, J.J.; McOrist, G.D.; Farrar, Y.J.

    1985-01-01

    Instrumental neutron activation analysis still remains the preferred option when analysing the trace element distribution in a wide rage of materials by neutron activation analysis. However, when lower limits of detection are required or major interferences reduce the effectiveness of this technique, radiochemical neutron activation analysis is applied. This paper examines the current use of both methods and the development of rapid radiochemical techniques for analysis of the biological materials, hair, cow's milk, human's milk, milk powder, blood and blood serum

  20. Wearable activity monitors in oncology trials: Current use of an emerging technology.

    Science.gov (United States)

    Gresham, Gillian; Schrack, Jennifer; Gresham, Louise M; Shinde, Arvind M; Hendifar, Andrew E; Tuli, Richard; Rimel, B J; Figlin, Robert; Meinert, Curtis L; Piantadosi, Steven

    2018-01-01

    Physical activity is an important outcome in oncology trials. Physical activity is commonly assessed using self-reported questionnaires, which are limited by recall and response biases. Recent advancements in wearable technology have provided oncologists with new opportunities to obtain real-time, objective physical activity data. The purpose of this review was to describe current uses of wearable activity monitors in oncology trials. We searched Pubmed, Embase, and the Cochrane Central Register of Controlled Trials for oncology trials involving wearable activity monitors published between 2005 and 2016. We extracted details on study design, types of activity monitors used, and purpose for their use. We summarized activity monitor metrics including step counts, sleep and sedentary time, and time spent in moderate-to-vigorous activity. We identified 41 trials of which 26 (63%) involved cancer survivors (post-treatment) and 15 trials (37%) involved patients with active cancer. Most trials (65%) involved breast cancer patients. Wearable activity monitors were commonly used in exercise (54%) or behavioral (29%) trials. Cancer survivors take between 4660 and 11,000 steps/day and those undergoing treatment take 2885 to 8300steps/day. Wearable activity monitors are increasingly being used to obtain objective measures of physical activity in oncology trials. There is potential for their use to expand to evaluate and predict clinical outcomes such as survival, quality of life, and treatment tolerance in future studies. Currently, there remains a lack of standardization in the types of monitors being used and how their data are being collected, analyzed, and interpreted. Recent advancements in wearable activity monitor technology have provided oncologists with new opportunities to monitor their patients' daily activity in real-world settings. The integration of wearable activity monitors into cancer care will help increase our understanding of the associations between

  1. Hypotheses about geoglyphs at Nasca, Peru: new discoveries

    Directory of Open Access Journals (Sweden)

    Jaroslav Klokočník

    2016-07-01

    Full Text Available The known hypotheses about the reasons why the geoglyphs in the Nasca and Palpa region of Peru were created are many: roads/paths, rituals/ceremonials, use of hallucinogens, astronomical meaning, influence of extraterrestrials, underground water… and so on. We present a new hypothesis, formulated by J. Sonnek (first published in 2011 in the context of all previous hypotheses.1 Sonnek explains the geoglyphs as tidied work areas for the production of rope and nets, although he goes much further than Stierlin. This eccentric hypothesis now has not only experimental but also archaeological and ethnographical support, which is presented here. Geoglyphs of a special shape were discovered in the pampas; they may represent technical objects – different types of ‘rope twisters’. Following this idea, Sonnek made technical devices (using today’s materials and tested them in practice; they work perfectly, see his YouTube videos.2 In November 2012, wooden pieces, which may be the remnants of ropemaking, were collected from the pampa near the towns of Nasca and Palpa, in vicinity of these hypothetic ropemaking places. Radiocarbon testing by 14C standardized radio-carbon age according to Stuiver-Polach convention and Accelerator Mass Spectroscopy (AMS of these wood pieces shows the age to be in a wide range from Early Nasca to the 17th century (and to our epoch with a fake geoglyph, too, thus supporting (but surely not proving the new hypothesis. Moreover, in the Quechua language, the word huasca, waskha (read: uasca means a rope or cord or place where these are produced. This word is very similar to ‘nasca’.

  2. Experienced physicians benefit from analyzing initial diagnostic hypotheses

    Directory of Open Access Journals (Sweden)

    Adam Bass

    2013-03-01

    Full Text Available Background: Most incorrect diagnoses involve at least one cognitive error, of which premature closure is the most prevalent. While metacognitive strategies can mitigate premature closure in inexperienced learners, these are rarely studied in experienced physicians. Our objective here was to evaluate the effect of analytic information processing on diagnostic performance of nephrologists and nephrology residents. Methods: We asked nine nephrologists and six nephrology residents at the University of Calgary and Glasgow University to diagnose ten nephrology cases. We provided presenting features along with contextual information, after which we asked for an initial diagnosis. We then primed participants to use either hypothetico-deductive reasoning or scheme-inductive reasoning to analyze the remaining case data and generate a final diagnosis. Results: After analyzing initial hypotheses, both nephrologists and residents improved the accuracy of final diagnoses (31.1% vs. 65.6%, p < 0.001, and 40.0% vs. 70.0%, p < 0.001, respectively. We found a significant interaction between experience and analytic processing strategy (p = 0.002: nephrology residents had significantly increased odds of diagnostic success when using scheme-inductive reasoning (odds ratio [95% confidence interval] 5.69 [1.59, 20.33], p = 0.007, whereas the performance of experienced nephrologists did not differ between strategies (odds ratio 0.57 [0.23, 1.39], p = 0.2. Discussion: Experienced nephrologists and nephrology residents can improve their performance by analyzing initial diagnostic hypotheses. The explanation of the interaction between experience and the effect of different reasoning strategies is unclear, but may relate to preferences in reasoning strategy, or the changes in knowledge structure with experience.

  3. Contribution of delayed rectifier potassium currents to the electrical activity of murine colonic smooth muscle

    Science.gov (United States)

    Koh, S D; Ward, S M; Dick, G M; Epperson, A; Bonner, H P; Sanders, K M; Horowitz, B; Kenyon, J L

    1999-01-01

    We used intracellular microelectrodes to record the membrane potential (Vm) of intact murine colonic smooth muscle. Electrical activity consisted of spike complexes separated by quiescent periods (Vm≈−60 mV). The spike complexes consisted of about a dozen action potentials of approximately 30 mV amplitude. Tetraethylammonium (TEA, 1–10 mM) had little effect on the quiescent periods but increased the amplitude of the action potential spikes. 4-Aminopyridine (4-AP, ⋧ 5 mM) caused continuous spiking.Voltage clamp of isolated myocytes identified delayed rectifier K+ currents that activated rapidly (time to half-maximum current, 11.5 ms at 0 mV) and inactivated in two phases (τf = 96 ms, τs = 1.5 s at 0 mV). The half-activation voltage of the permeability was −27 mV, with significant activation at −50 mV.TEA (10 mM) reduced the outward current at potentials positive to 0 mV. 4-AP (5 mM) reduced the early current but increased outward current at later times (100–500 ms) consistent with block of resting channels relieved by depolarization. 4-AP inhibited outward current at potentials negative to −20 mV, potentials where TEA had no effect.Qualitative PCR amplification of mRNA identified transcripts encoding delayed rectifier K+ channel subunits Kv1.6, Kv4.1, Kv4.2, Kv4.3 and the Kvβ1.1 subunit in murine colon myocytes. mRNA encoding Kv 1.4 was not detected.We find that TEA-sensitive delayed rectifier currents are important determinants of action potential amplitude but not rhythmicity. Delayed rectifier currents sensitive to 4-AP are important determinants of rhythmicity but not action potential amplitude. PMID:10050014

  4. Current clinical evidence on pioglitazone pharmacogenomics

    Directory of Open Access Journals (Sweden)

    Marina eKawaguchi-Suzuki

    2013-11-01

    Full Text Available Pioglitazone is the most widely used thiazolidinedione and acts as an insulin-sensitizer through activation of the Peroxisome Proliferator-Activated Receptor-γ (PPARγ. Pioglitazone is approved for use in the management of type 2 diabetes mellitus, but its use in other therapeutic areas is increasing due to pleiotropic effects. In this hypothesis article, the current clinical evidence on pioglitazone pharmacogenomics is summarized and related to variability in pioglitazone response. How genetic variation in the human genome affects the pharmacokinetics and pharmacodynamics of pioglitazone was examined. For pharmacodynamic effects, hypoglycemic and anti-atherosclerotic effects, risks of fracture or edema, and the increase in body mass index in response to pioglitazone based on genotype were examined. The genes CYP2C8 and PPARG are the most extensively studied to date and selected polymorphisms contribute to respective variability in pioglitazone pharmacokinetics and pharmacodynamics. We hypothesized that genetic variation in pioglitazone pathway genes contributes meaningfully to the clinically observed variability in drug response. To test the hypothesis that genetic variation in PPARG associates with variability in pioglitazone response, we conducted a meta-analysis to synthesize the currently available data on the PPARG p.Pro12Ala polymorphism. The results showed that PPARG 12Ala carriers had a more favorable change in fasting blood glucose from baseline as compared to patients with the wild-type Pro12Pro genotype (p=0.018. Unfortunately, findings for many other genes lack replication in independent cohorts to confirm association; further studies are needed. Also, the biological functionality of these polymorphisms is unknown. Based on current evidence, we propose that pharmacogenomics may provide an important tool to individualize pioglitazone therapy and better optimize therapy in patients with T2DM or other conditions for which pioglitazone

  5. Current NDT activities at Cekmece Nuclear Research and Training Center

    International Nuclear Information System (INIS)

    Ekinci, S.

    2004-01-01

    Nondestructive testing (NDT) activities at Cekmece Nuclear Research and Training Center (CNAEM) has been initiated in the Industrial Application Department of the Center which was established in 1976 as the Radioisotope Applications Group for Industry. The Department started its first NDT activity with industrial radiography. The NDT activities have been developed by the support of various national (State Planning Organization (DPT)) and international (IAEA and UNDP) projects. Today, there are five basic NDT techniques (radiography, ultrasonic, magnetic particle, liquid penetrant and eddy current) used in the Industrial Application Department. The Department arranges routinely NDT qualification courses according to ISO 9712 and TS EN 473 standards for level 1 and 2 for Turkish Industry. It also carries out national DPT and IAEA Technical Co-operation projects and gives NDT services in the laboratory and in the field. Digital radiography and digital ultrasonic techniques are being used in advanced NDT applications. This paper describes the NDT activities of CNAEM. (author)

  6. Differential contribution of Ca2+ sources to day and night BK current activation in the circadian clock.

    Science.gov (United States)

    Whitt, Joshua P; McNally, Beth A; Meredith, Andrea L

    2018-02-05

    Large conductance K + (BK) channels are expressed widely in neurons, where their activation is regulated by membrane depolarization and intracellular Ca 2+ (Ca 2+ i ). To enable this regulation, BK channels functionally couple to both voltage-gated Ca 2+ channels (VGCCs) and channels mediating Ca 2+ release from intracellular stores. However, the relationship between BK channels and their specific Ca 2+ source for particular patterns of excitability is not well understood. In neurons within the suprachiasmatic nucleus (SCN)-the brain's circadian clock-BK current, VGCC current, and Ca 2+ i are diurnally regulated, but paradoxically, BK current is greatest at night when VGCC current and Ca 2+ i are reduced. Here, to determine whether diurnal regulation of Ca 2+ is relevant for BK channel activation, we combine pharmacology with day and night patch-clamp recordings in acute slices of SCN. We find that activation of BK current depends primarily on three types of channels but that the relative contribution changes between day and night. BK current can be abrogated with nimodipine during the day but not at night, establishing that L-type Ca 2+ channels (LTCCs) are the primary daytime Ca 2+ source for BK activation. In contrast, dantrolene causes a significant decrease in BK current at night, suggesting that nighttime BK activation is driven by ryanodine receptor (RyR)-mediated Ca 2+ i release. The N- and P/Q-type Ca 2+ channel blocker ω-conotoxin MVIIC causes a smaller reduction of BK current that does not differ between day and night. Finally, inhibition of LTCCs, but not RyRs, eliminates BK inactivation, but the BK β2 subunit was not required for activation of BK current by LTCCs. These data reveal a dynamic coupling strategy between BK channels and their Ca 2+ sources in the SCN, contributing to diurnal regulation of SCN excitability. © 2018 Whitt et al.

  7. Hyperpolarization-activated current (I(h)) in vestibular calyx terminals: characterization and role in shaping postsynaptic events.

    Science.gov (United States)

    Meredith, Frances L; Benke, Tim A; Rennie, Katherine J

    2012-12-01

    Calyx afferent terminals engulf the basolateral region of type I vestibular hair cells, and synaptic transmission across the vestibular type I hair cell/calyx is not well understood. Calyces express several ionic conductances, which may shape postsynaptic potentials. These include previously described tetrodotoxin-sensitive inward Na(+) currents, voltage-dependent outward K(+) currents and a K(Ca) current. Here, we characterize an inwardly rectifying conductance in gerbil semicircular canal calyx terminals (postnatal days 3-45), sensitive to voltage and to cyclic nucleotides. Using whole-cell patch clamp, we recorded from isolated calyx terminals still attached to their type I hair cells. A slowly activating, noninactivating current (I(h)) was seen with hyperpolarizing voltage steps negative to the resting potential. External Cs(+) (1-5 mM) and ZD7288 (100 μM) blocked the inward current by 97 and 83 %, respectively, confirming that I(h) was carried by hyperpolarization-activated, cyclic nucleotide gated channels. Mean half-activation voltage of I(h) was -123 mV, which shifted to -114 mV in the presence of cAMP. Activation of I(h) was well described with a third order exponential fit to the current (mean time constant of activation, τ, was 190 ms at -139 mV). Activation speeded up significantly (τ=136 and 127 ms, respectively) when intracellular cAMP and cGMP were present, suggesting that in vivo I(h) could be subject to efferent modulation via cyclic nucleotide-dependent mechanisms. In current clamp, hyperpolarizing current steps produced a time-dependent depolarizing sag followed by either a rebound afterdepolarization or an action potential. Spontaneous excitatory postsynaptic potentials (EPSPs) became larger and wider when I(h) was blocked with ZD7288. In a three-dimensional mathematical model of the calyx terminal based on Hodgkin-Huxley type ionic conductances, removal of I(h) similarly increased the EPSP, whereas cAMP slightly decreased simulated EPSP size

  8. Data Mining Activities for Bone Discipline - Current Status

    Science.gov (United States)

    Sibonga, J. D.; Pietrzyk, R. A.; Johnston, S. L.; Arnaud, S. B.

    2008-01-01

    The disciplinary goals of the Human Research Program are broadly discussed. There is a critical need to identify gaps in the evidence that would substantiate a skeletal health risk during and after spaceflight missions. As a result, data mining activities will be engaged to gather reviews of medical data and flight analog data and to propose additional measures and specific analyses. Several studies are briefly reviewed which have topics that partially address these gaps in knowledge, including bone strength recovery with recovery of bone mass density, current renal stone formation knowledge, herniated discs, and a review of bed rest studies conducted at Ames Human Research Facility.

  9. Validity of the Environmental Kuznets Curve Hypotheses in Water Pollution A Case Study

    Directory of Open Access Journals (Sweden)

    Hediyeh Alishiri

    2017-03-01

    Full Text Available Among the different environmental pollutions, water pollution is of especial importance due to the rather unchanging supply of this vital resource on a global scale and because of the dire consequences of its pollution for human health. The relationship between water production and its pollution can thus established and used as a measure of environmental degradation. This relationship can then be captured and analyzed in terms of environmental Kuznets hypotheses. It may be claimed that the early stages of economic growth is associated with lower per capita income and water pollution but the trend is reversed with increasing per capita income and improved economic growth. The present study was conducted using the panel data technique and the Kuznets environmental hypotheses were examined for the two groups of developed and developing countries under the two scenarios of using either per capita GDP or the share of industry to the added value in GDP as an indicator of economic growth. Results indicate that under both scenarios, Kuznets hypotheses are confirmed when studying the situation in developing countries but refuted in the case of developed countries.

  10. The current implementation status of the integration of sports and physical activity into Dutch rehabilitation care.

    Science.gov (United States)

    Hoekstra, Femke; Hettinga, Florentina J; Alingh, Rolinde A; Duijf, Marjo; Dekker, Rienk; van der Woude, Lucas H V; van der Schans, Cees P

    2017-01-01

    To describe the current status of the nationwide implementation process of a sports and physical activity stimulation programme to gain insight into how sports and physical activity were integrated into Dutch rehabilitation care. The current implementation status of a sports and physical activity stimulation programme in 12 rehabilitation centres and 5 hospitals with a rehabilitation department was described by scoring fidelity and satisfaction. Seventy-one rehabilitation professionals filled out a questionnaire on how sports and physical activity, including stimulation activities, were implemented into rehabilitation care. Total fidelity scores (in %) were calculated for each organization. Professionals' satisfaction was rated on a scale from 1 to 10. In most organizations sports and physical activity were to some extent integrated during and after rehabilitation (fidelity scores: median = 54%, IQR = 23%). Physical activity stimulation was not always embedded as standard component of a rehabilitation treatment. Professionals' satisfaction rated a median value of 8.0 (IQR = 0.0) indicating high satisfaction rates. The fidelity outcome showed that activities to stimulate sports and physical activity during and after rehabilitation were integrated into rehabilitation care, but not always delivered as standardized component. These findings have emphasized the importance to focus on integrating these activities into routines of organizations. Implications for Rehabilitation Components of an evidence-based programme to stimulate sports and physical activity during and after rehabilitation can be used to measure the current status of the integration of sports and physical activity in rehabilitation care in a structural and effective way. The method described in the current study can be used to compare the content of the rehabilitation care regarding the integration of sports and physical activity among organizations both on a national and international level

  11. Hypotheses on citation practices as revealed in the literature of the ...

    African Journals Online (AJOL)

    Citations found in two historical articles, which appeared in Cancer Research, a top American Journal, were used to show both positive and negative attitudes towards my 22 historical publications on cancer carriage in the body. Therefore, scientific information concepts are cited critically and two hypotheses are advanced ...

  12. Examining Preservice Science Teachers' Skills of Formulating Hypotheses and Identifying Variables

    Science.gov (United States)

    Aydogdu, Bülent

    2015-01-01

    The aim of this study is to examine preservice science teachers' skills of formulating hypotheses and identifying variables. The research has a phenomenological research design. The data was gathered qualitatively. In this study, preservice science teachers were first given two scenarios (Scenario-1 & Scenario-2) containing two different…

  13. Thymus is enlarged in children with current atopic dermatitis. A cross-sectional study

    DEFF Research Database (Denmark)

    Olesen, Anne Braae; Andersen, Gratien; Jeppesen, Dorthe

    2005-01-01

    Atopic dermatitis is a common skin disorder of unknown aetiology with peak incidence in early childhood. The disease is associated with peripheral T-cell accumulation in the skin. The thymus is a key organ of the cellular immune response early in life. We hypothesized that atopic dermatitis...... is associated with an unbalanced establishment of the peripheral T-lymphocyte system. This cross-sectional study was performed to compare thymus sizes in patients with atopic dermatitis and healthy controls. Thirty-seven children with current atopic dermatitis were enrolled and compared with 29 healthy controls...... of thymus is compatible with increased thymic activity and emission of T lymphocytes....

  14. Experimental study of anti-tumor activity of direct current

    International Nuclear Information System (INIS)

    Ito, Hisao; Hashimoto, Shozo

    1989-01-01

    The anti-tumor activity of direct current combined with radiation was studied. The experiments were performed with fibrosarcomas (FSA, NFSA) syngenetic to C3H mice. Direct current (0.6mA, 120min) alone was effective to reduce the tumor sizes, but could not cure the tumors. When the direct current therapy (DC therapy) was combined with radiation the DC therapy following radiation was more effective than that before radiation. Using TCD 50 assay, the DC therapy enhanced the effect of a single dose of radiation with the dose-modifying factor of 1.2. However, tumor control rates by the combination therapy were more improved at the smaller doses of radiation than at the larger ones. When the single DC therapy (0.6mA, 120min) was applied immediately after the first radiation of fractionated one the combination therapy still showed the enhanced effect. However, both DC therapy and the radiation therapy were divided in three fractions, and the DC therapy (0.6mA, 40min) was applied after each radiation. Tumor growth retardation by the combination therapy was no different from that by radiation alone. This result suggests that there might be a minimum required dose of coulombs to show the effect of the combination therapy. (author)

  15. Vertically oriented graphene bridging active-layer/current-collector interface for ultrahigh rate supercapacitors.

    Science.gov (United States)

    Bo, Zheng; Zhu, Weiguang; Ma, Wei; Wen, Zhenhai; Shuai, Xiaorui; Chen, Junhong; Yan, Jianhua; Wang, Zhihua; Cen, Kefa; Feng, Xinliang

    2013-10-25

    Dense networks of graphene nanosheets standing vertically on a current collector can work as numerous electrically conductive bridges to facilitate charge transport and mitigate the constriction/spreading resistance at the interface between the active material and the current collector. The vertically oriented graphene-bridged supercapacitors present excellent rate and power capabilities. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Current Limitations and Recommendations to Improve Testing for the Environmental Assessment of Endocrine Active Substances

    DEFF Research Database (Denmark)

    Coady, Katherine K; Biever, Ronald C; Denslow, Nancy D

    2017-01-01

    In this paper existing regulatory frameworks and test systems for assessing potential endocrine-active chemicals are described, and associated challenges discussed, along with proposed approaches to address these challenges. Regulatory frameworks vary somewhat across geographies, but all basically...... evaluate whether a chemical possesses endocrine activity and whether this activity can result in adverse outcomes either to humans or the environment. Current test systems include in silico, in vitro and in vivo techniques focused on detecting potential endocrine activity, and in vivo tests that collect...... methods currently do not exist, and addressing key endocrine pathways of possible concern in addition to those associated with estrogen, androgen and thyroid signaling. This article is protected by copyright. All rights reserved....

  17. Hypothesized eye movements of neurolinguistic programming: a statistical artifact.

    Science.gov (United States)

    Farmer, A; Rooney, R; Cunningham, J R

    1985-12-01

    Neurolinguistic programming's hypothesized eye-movements were measured independently from videotapes of 30 subjects, aged 15 to 76 yr., who were asked to recall visual pictures, recorded audio sounds, and textural objects. chi 2 indicated that subjects' responses were significantly different from those predicted. When chi 2 comparisons were weighted by number of eye positions assigned to each modality (3 visual, 3 auditory, 1 kinesthetic), subjects' responses did not differ significantly from the expected pattern. These data indicate that the eye-movement hypothesis may represent randomly occurring rather than sensory-modality-related positions.

  18. Active Search for Antecedents in Cataphoric Pronoun Resolution

    Directory of Open Access Journals (Sweden)

    Leticia ePablos

    2015-10-01

    Full Text Available Cataphoric dependencies where a pronoun precedes its antecedent appear to call on different mechanisms in language comprehension from forward dependencies where the antecedent precedes the pronoun. Previous research has shown that the resolution of cataphoric dependencies involves predictive processes such as the Active Search Mechanism, which hypothesizes the automatic search for an antecedent immediately after encountering a cataphoric pronoun. The current study employs gender mismatch to investigate whether the active search for an antecedent of a cataphoric pronoun is restricted only to grammatically licit positions. We present results from an event-related potential experiment on the reading comprehension of cataphoric dependencies in Dutch. Results show that gender mismatch gives rise to an anterior negativity at grammatically licit antecedent positions only. We hypothesize that this negativity reflects the prediction failure for an antecedent after encountering a pronoun, rather than a gender mismatch. We discuss the timing, topography and functionality of this negativity with respect to previous studies and how this relates to the ERPs elicited in the processing of structural constraints on pronoun resolution.

  19. Foraging response and acclimation of ambush feeding and feeding-current feeding copepods to toxic dinoflagellates

    DEFF Research Database (Denmark)

    Xu, Jiayi; Nielsen, Lasse Tor; Kiørboe, Thomas

    2018-01-01

    reticulatum. We hypothesize (1) that ambush feeders are less affected by toxic algae than feeding-current feeders, (2) that copepods acclimate to the toxic algae, and (3) that phytoplankton cells previously exposed to copepod cues elicit stronger responses. Both copepod species consumed the toxic algae...... to examine the response and temporal acclimation (5 d) of two copepods with different foraging behaviors to toxic dinoflagellates. Feeding-current feeding Temora longicornis and ambush feeding Acartia tonsa were offered three strains of toxic Alexandrium tamarense and a nontoxic control Protoceratium...... at a reduced rate and there was no difference in their net-response, but the mechanisms differed. T. longicornis responded in strain-specific ways by reducing its feeding activity, by rejecting captured algae, or by regurgitating consumed cells. A. tonsa reduced its consumption rate, jump frequency, and jump...

  20. Novel dimeric bis(7)-tacrine proton-dependently inhibits NMDA-activated currents

    International Nuclear Information System (INIS)

    Luo, Jialie; Li, Wenming; Liu, Yuwei; Zhang, Wei; Fu, Hongjun; Lee, Nelson T.K.; Yu, Hua; Pang, Yuanping; Huang, Pingbo; Xia, Jun; Li, Zhi-Wang; Li, Chaoying; Han, Yifan

    2007-01-01

    Bis(7)-tacrine has been shown to prevent glutamate-induced neuronal apoptosis by blocking NMDA receptors. However, the characteristics of the inhibition have not been fully elucidated. In this study, we further characterize the features of bis(7)-tacrine inhibition of NMDA-activated current in cultured rat hippocampal neurons. The results show that with the increase of extracellular pH, the inhibitory effect decreases dramatically. At pH 8.0, the concentration-response curve of bis(7)-tacrine is shifted rightwards with the IC 50 value increased from 0.19 ± 0.03 μM to 0.41 ± 0.04 μM. In addition, bis(7)-tacrine shifts the proton inhibition curve rightwards. Furthermore, the inhibitory effect of bis(7)-tacrine is not altered by the presence of the NMDA receptor proton sensor shield spermidine. These results indicate that bis(7)-tacrine inhibits NMDA-activated current in a pH-dependent manner by sensitizing NMDA receptors to proton inhibition, rendering it potentially beneficial therapeutic effects under acidic conditions associated with stroke and ischemia

  1. The effect of physical activity on mood - a review of current literature

    Directory of Open Access Journals (Sweden)

    Mateusz Łakomski

    2017-04-01

    Full Text Available The impact of physical activity on human health has many benefits. Equally important in improving physical fitness and normalizing cardiovascular system seems to be the impact of exercise on mood of patients. Physical activity improves well-being, satisfaction and self-confidence. However, the condition of effective therapeutic intervention is due to its regularity, since only systematic exercises allow to maintain the beneficial effects of physical activity. Otherwise, the results achieved are only temporary. This article aims to review the current literature and show the most important aspects of motion therapy in improving the psychophysical condition of patients.

  2. Neurokinin-1 receptor activation in globus pallidus

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2009-10-01

    Full Text Available The undecapeptide substance P has been demonstrated to modulate neuronal activity in a number of brain regions by acting on neurokinin-1 receptors. Anatomical studies revealed a moderate level of neurokinin-1 receptor in rat globus pallidus. To determine the electrophysiological effects of neurokinin-1 receptor activation in globus pallidus, whole-cell patch-clamp recordings were performed in the present study. Under current-clamp recordings, neurokinin-1 receptor agonist, [Sar9, Met(O211] substance P (SM-SP at 1 μM, depolarized globus pallidus neurons and increased their firing rate. Consistently, SM-SP induced an inward current under voltage-clamp recording. The depolarization evoked by SM-SP persisted in the presence of tetrodotoxin, glutamate and GABA receptor antagonists, indicating its direct postsynaptic effects. The neurokinin-1 receptor antagonist, SR140333B, could block SM-SP-induced depolarization. Further experiments showed that suppression of potassium conductance was the predominant ionic mechanism of SM-SP-induced depolarization. To determine if neurokinin-1 receptor activation exerts any effects on GABAergic and glutamatergic neurotransmission, the action of SM-SP on synaptic currents was studied. SM-SP significantly increased the frequency of spontaneous inhibitory postsynaptic currents, but only induced a transient increase in the frequency of miniature inhibitory postsynaptic currents. No change was observed in both spontaneous and miniature excitatory postsynaptic currents. Based on the direct excitatory effects of SM-SP on pallidal neurons, we hypothesize that neurokinin-1 receptor activation in globus pallidus may be involved in the beneficial effect of substance P in Parkinson’s disease.

  3. Economic stress and low leisure-time physical activity: Two life course hypotheses

    Directory of Open Access Journals (Sweden)

    Martin Lindström

    2018-04-01

    Full Text Available The aim was to investigate associations between economic stress in childhood and adulthood, and low leisure-time physical activity (LTPA in adulthood from two life course perspectives. The public health survey in Scania in the southernmost part of Sweden in 2012 is a cross-sectional study based on a stratified random sample with 28,029 respondents aged 18–80 (51.7% response rate. Associations between childhood and adult economic stress, and low LTPA were analyzed with logistic regressions. A 14.8% prevalence of men and 13.5% of women had low LTPA (sedentary lifestyle. Low LTPA was associated with higher age, being born abroad, low socioeconomic status, low trust, smoking, poor self-rated health, and economic stress in childhood and adulthood. The odds ratios of low LTPA increased with more accumulated economic stress across the life course in a dose-response relationship. There was no specific critical period (childhood or adulthood, because economic stress in childhood and adulthood were both associated with low LTPA but the associations were attenuated after the introduction of smoking and self-rated health. The accumulation hypothesis was supported because the odds ratios of low LTPA indicated a graded response to life course economic stress. The critical period hypothesis was thus not supported. Economic stress across the life course seems to be associated with low LTPA in adulthood. Keywords: Economic stress, Leisure-time physical activity, Accumulation, Critical period, Social capital, Sweden

  4. NegaWatt 2011-2050 scenario - Hypotheses and method. Technical report, May 2014

    International Nuclear Information System (INIS)

    2014-05-01

    This report proposes an analysis of the negaWatt 2011 scenario. It describes in detail the methodology adopted to elaborate this prospective scenario, and presents the major part of the hypotheses which structure this scenario. A first part presents the approach and methodology (constraints, scenario, model). The second part addresses the issue of energy saving and energy efficiency through a sector-based analysis (housing and office building, transports, industrial and agricultural production). The third part studies the substitution by renewable energies through a supply analysis: energy production based on biomass, renewable energies, and fissile and fossil energies. It outlines the major role of grids in the supply-demand balance. The results of the negaWatt 2011 scenario are presented in terms of final energy, primary energies, and impact on greenhouse gas emissions. Hypotheses and results related to the different sectors (building, transports, industry and agriculture, energy production) are given in appendix

  5. A comparison of professional-level faculty and student perceptions of active learning: its current use, effectiveness, and barriers

    Science.gov (United States)

    Metz, Michael J.

    2014-01-01

    Active learning is an instructional method in which students become engaged participants in the classroom through the use of in-class written exercises, games, problem sets, audience-response systems, debates, class discussions, etc. Despite evidence supporting the effectiveness of active learning strategies, minimal adoption of the technique has occurred in many professional programs. The goal of this study was to compare the perceptions of active learning between students who were exposed to active learning in the classroom (n = 116) and professional-level physiology faculty members (n = 9). Faculty members reported a heavy reliance on lectures and minimal use of educational games and activities, whereas students indicated that they learned best via the activities. A majority of faculty members (89%) had observed active learning in the classroom and predicted favorable effects of the method on student performance and motivation. The main reported barriers by faculty members to the adoption of active learning were a lack of necessary class time, a high comfort level with traditional lectures, and insufficient time to develop materials. Students hypothesized similar obstacles for faculty members but also associated many negative qualities with the traditional lecturers. Despite these barriers, a majority of faculty members (78%) were interested in learning more about the alternative teaching strategy. Both faculty members and students indicated that active learning should occupy portions (29% vs. 40%) of face-to-face class time. PMID:25179615

  6. Exhaustive sampling of docking poses reveals binding hypotheses for propafenone type inhibitors of P-glycoprotein.

    Directory of Open Access Journals (Sweden)

    Freya Klepsch

    2011-05-01

    Full Text Available Overexpression of the xenotoxin transporter P-glycoprotein (P-gp represents one major reason for the development of multidrug resistance (MDR, leading to the failure of antibiotic and cancer therapies. Inhibitors of P-gp have thus been advocated as promising candidates for overcoming the problem of MDR. However, due to lack of a high-resolution structure the concrete mode of interaction of both substrates and inhibitors is still not known. Therefore, structure-based design studies have to rely on protein homology models. In order to identify binding hypotheses for propafenone-type P-gp inhibitors, five different propafenone derivatives with known structure-activity relationship (SAR pattern were docked into homology models of the apo and the nucleotide-bound conformation of the transporter. To circumvent the uncertainty of scoring functions, we exhaustively sampled the pose space and analyzed the poses by combining information retrieved from SAR studies with common scaffold clustering. The results suggest propafenone binding at the transmembrane helices 5, 6, 7 and 8 in both models, with the amino acid residue Y307 playing a crucial role. The identified binding site in the non-energized state is overlapping with, but not identical to, known binding areas of cyclic P-gp inhibitors and verapamil. These findings support the idea of several small binding sites forming one large binding cavity. Furthermore, the binding hypotheses for both catalytic states were analyzed and showed only small differences in their protein-ligand interaction fingerprints, which indicates only small movements of the ligand during the catalytic cycle.

  7. Feeding activity of mussels Mytilus edulis related to near-bed currents and phytoplankton biomass

    DEFF Research Database (Denmark)

    Dolmer, Per

    2000-01-01

    The feeding activity of blue mussels Mytilus edulis was investigated in the field and related to near-bottom current velocities and the phytoplankton biomass in the near-bottom water layers for four days. The body content of Chl-a in mussels and their shell gap size were used as indices of filtra......The feeding activity of blue mussels Mytilus edulis was investigated in the field and related to near-bottom current velocities and the phytoplankton biomass in the near-bottom water layers for four days. The body content of Chl-a in mussels and their shell gap size were used as indices...... of filtration activity. During days 1 and 2 the near-bed current velocities were low (1.2-2.1 cm s(-1)), and the near-bed phytoplankton biomass was at the same time lower than near the water surface. Between 44 and 69% of the mussels had closed shells and accumulated only small amounts of Chl-a in the body....... During day 3 and day 4 the near-bed current velocities increased to 6.5 and 3.9 cm s(-1). respectively, and the Chl-a was homogeneously distributed in the water column. Now only 17 and 25% of the mussels had closed valves and they accumulated a larger amount of Chl-a. The actual population filtration...

  8. Magnesium Counteracts Vascular Calcification: Passive Interference or Active Modulation?

    Science.gov (United States)

    Ter Braake, Anique D; Shanahan, Catherine M; de Baaij, Jeroen H F

    2017-08-01

    Over the last decade, an increasing number of studies report a close relationship between serum magnesium concentration and cardiovascular disease risk in the general population. In end-stage renal disease, an association was found between serum magnesium and survival. Hypomagnesemia was identified as a strong predictor for cardiovascular disease in these patients. A substantial body of in vitro and in vivo studies has identified a protective role for magnesium in vascular calcification. However, the precise mechanisms and its contribution to cardiovascular protection remain unclear. There are currently 2 leading hypotheses: first, magnesium may bind phosphate and delay calcium phosphate crystal growth in the circulation, thereby passively interfering with calcium phosphate deposition in the vessel wall. Second, magnesium may regulate vascular smooth muscle cell transdifferentiation toward an osteogenic phenotype by active cellular modulation of factors associated with calcification. Here, the data supporting these major hypotheses are reviewed. The literature supports both a passive inorganic phosphate-buffering role reducing hydroxyapatite formation and an active cell-mediated role, directly targeting vascular smooth muscle transdifferentiation. However, current evidence relies on basic experimental designs that are often insufficient to delineate the underlying mechanisms. The field requires more advanced experimental design, including determination of intracellular magnesium concentrations and the identification of the molecular players that regulate magnesium concentrations in vascular smooth muscle cells. © 2017 American Heart Association, Inc.

  9. THE EVOLUTION OF THE ELECTRIC CURRENT DURING THE FORMATION AND ERUPTION OF ACTIVE-REGION FILAMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jincheng; Yan, Xiaoli; Qu, Zhongquan; Xue, Zhike; Xiang, Yongyuan; Li, Hao, E-mail: egnever@ynao.ac.cn [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China)

    2016-02-01

    We present a comprehensive study of the electric current related to the formation and eruption of active region filaments in NOAA AR 11884. The vertical current on the solar surface was investigated by using vector magnetograms (VMs) observed by HMI on board the Solar Dynamics Observatory. To obtain the electric current along the filament's axis, we reconstructed the magnetic fields above the photosphere by using nonlinear force-free field extrapolation based on photospheric VMs. Spatio-temporal evolutions of the vertical current on the photospheric surface and the horizontal current along the filament's axis were studied during the long-term evolution and eruption-related period, respectively. The results show that the vertical currents of the entire active region behaved with a decreasing trend and the magnetic fields also kept decreasing during the long-term evolution. For the eruption-related evolution, the mean transverse field strengths decreased before two eruptions and increased sharply after two eruptions in the vicinity of the polarity inversion lines underneath the filament. The related vertical current showed different behaviors in two of the eruptions. On the other hand, a very interesting feature was found: opposite horizontal currents with respect to the current of the filament's axis appeared and increased under the filament before the eruptions and disappeared after the eruptions. We suggest that these opposite currents were carried by the new flux emerging from the photosphere bottom and might be the trigger mechanism for these filament eruptions.

  10. Calcium current activation kinetics in isolated pyramidal neurones of the Ca1 region of the mature guinea-pig hippocampus.

    Science.gov (United States)

    Kay, A R; Wong, R K

    1987-11-01

    1. Neurones were isolated from the CA1 region of the guinea-pig hippocampus and subjected to the whole-cell mode of voltage clamping, to determine the kinetics of voltage-gated Ca2+ channel activation. 2. Isolated neurones had an abbreviated morphology, having lost most of the distal dendritic tree during the isolation procedure. The electrical compactness of the cells facilitates voltage clamp analysis. 3. Block of sodium and potassium currents revealed a persistent current activated on depolarization above -40 mV, which inactivated slowly when the intracellular medium contained EGTA. The current was blocked by Co2+ and Cd2+, augmented by increases in Ca2+ and could be carried by Ba2+, suggesting that the current is borne by Ca2+. 4. Steady-state activation of the Ca2+ current was found to be well described by the Boltzman equation raised to the second power. 5. The open channel's current-voltage (I-V) relationship rectified in the inward direction and was consistent with the constant-field equation. 6. The kinetics of Ca2+ current onset followed m2 kinetics throughout the range of its activation. Tail current kinetics were in accord with this model. A detailed Hodgkin-Huxley model was derived, defining the activation of this current. 7. The kinetics of the currents observed in this regionally and morphologically defined class of neurones were consistent with the existence of a single kinetic class of channels.

  11. Radio Astronomy in Malaysia: Current Status and Outreach Activities

    Science.gov (United States)

    Hashim, N.; Abidin, Z. Z.; Ibrahim, U. F. S. U.; Umar, R.; Hassan, M. S. R.; Rosli, Z.; Hamidi, Z. S.; Ibrahim, Z. A.

    2011-12-01

    In this paper, we will present the current status of radio astronomical research and outreach in Malaysia. We will also present a short history of our research group, which is currently the only radio astronomical facility in Malaysia. Our group is called the Radio Cosmology Research Lab and was established in 2005 by Dr Zamri Zainal Abidin and Prof Dr Zainol Abidin Ibrahim. We will discuss the future plans for this group including our keen interest in being part of a more global network of radio astronomers. We are already an active member of the South-East Asia Astronomy Network (SEAAN) and aims to have a radio astronomical facility in order to join the Global Very Long Baseline Interferometer (VLBI) as well becoming a research hub for the future Square Kilometer Array (SKA) project. We will also present some of the scientific goals of our group including providing a platform for radio astronomers to be able to do observations of weak and high red-shifted radio objects such as galaxy clusters and supernovae.

  12. Properties of hypothesis testing techniques and (Bayesian) model selection for exploration-based and theory-based (order-restricted) hypotheses.

    Science.gov (United States)

    Kuiper, Rebecca M; Nederhoff, Tim; Klugkist, Irene

    2015-05-01

    In this paper, the performance of six types of techniques for comparisons of means is examined. These six emerge from the distinction between the method employed (hypothesis testing, model selection using information criteria, or Bayesian model selection) and the set of hypotheses that is investigated (a classical, exploration-based set of hypotheses containing equality constraints on the means, or a theory-based limited set of hypotheses with equality and/or order restrictions). A simulation study is conducted to examine the performance of these techniques. We demonstrate that, if one has specific, a priori specified hypotheses, confirmation (i.e., investigating theory-based hypotheses) has advantages over exploration (i.e., examining all possible equality-constrained hypotheses). Furthermore, examining reasonable order-restricted hypotheses has more power to detect the true effect/non-null hypothesis than evaluating only equality restrictions. Additionally, when investigating more than one theory-based hypothesis, model selection is preferred over hypothesis testing. Because of the first two results, we further examine the techniques that are able to evaluate order restrictions in a confirmatory fashion by examining their performance when the homogeneity of variance assumption is violated. Results show that the techniques are robust to heterogeneity when the sample sizes are equal. When the sample sizes are unequal, the performance is affected by heterogeneity. The size and direction of the deviations from the baseline, where there is no heterogeneity, depend on the effect size (of the means) and on the trend in the group variances with respect to the ordering of the group sizes. Importantly, the deviations are less pronounced when the group variances and sizes exhibit the same trend (e.g., are both increasing with group number). © 2014 The British Psychological Society.

  13. De bruikbaarheid van de ‘shaken baby syndroom’-hypothese in het strafproces

    NARCIS (Netherlands)

    Hoving, R.A.

    In het Nederlandse strafproces wordt regelmatig gebruik gemaakt van deskundigenbewijs van deskundigen die uitgaan van de ‘shaken baby syndroom’-hypothese om aan te tonen dat een verdachte een baby heeft mishandeld of gedood. In onder meer de Verenigde Staten en Engeland woedt een felle discussie

  14. The Ranschburg Effect: Tests of the Guessing-Bias and Proactive Interference Hypotheses

    Science.gov (United States)

    Walsh, Michael F.; Schwartz, Marian

    1977-01-01

    The guessing-bias and proactive interference hypotheses of the Ranschburg Effect were investigated by giving three groups different instructions as to guessing during recall. Results failed to support the prediction that the effect should be reduced or eliminated on shift trials. Neither hypothesis received significant support. (CHK)

  15. Na(+)/K(+) pump interacts with the h-current to control bursting activity in central pattern generator neurons of leeches.

    Science.gov (United States)

    Kueh, Daniel; Barnett, William H; Cymbalyuk, Gennady S; Calabrese, Ronald L

    2016-09-02

    The dynamics of different ionic currents shape the bursting activity of neurons and networks that control motor output. Despite being ubiquitous in all animal cells, the contribution of the Na(+)/K(+) pump current to such bursting activity has not been well studied. We used monensin, a Na(+)/H(+) antiporter, to examine the role of the pump on the bursting activity of oscillator heart interneurons in leeches. When we stimulated the pump with monensin, the period of these neurons decreased significantly, an effect that was prevented or reversed when the h-current was blocked by Cs(+). The decreased period could also occur if the pump was inhibited with strophanthidin or K(+)-free saline. Our monensin results were reproduced in model, which explains the pump's contributions to bursting activity based on Na(+) dynamics. Our results indicate that a dynamically oscillating pump current that interacts with the h-current can regulate the bursting activity of neurons and networks.

  16. Procoagulant State in Current and Former Anabolic Androgenic Steroid Abusers

    DEFF Research Database (Denmark)

    Chang, Simon; Rasmussen, Jon J; Frandsen, Mikkel N

    2018-01-01

    BACKGROUND:  Anabolic androgenic steroid (AAS) abusers are considered at increased risk of cardiovascular morbidity and mortality. We hypothesized that current and former AAS abuse would induce a procoagulant shift in the haemostatic balance. METHODS:  Men 18 to 50 years of age were included...

  17. Uranium exploration in Egypt past, current and future activities

    International Nuclear Information System (INIS)

    Farag, N.

    2014-01-01

    The Egyptian Nuclear Materials Authority (NMA), is the government body responsible for exploration of the nuclear raw materials in the country. The early NMA U-exploration activities has included training of exploration teams, conduction of airborne, ground follow up and preliminary geological mapping as well as execution of limited exploration drilling. A number of TC projects and expert missions were mainly executed in collaboration with the IAEA for this purpose. These efforts have resulted in the discovery of seven U-potential prospects. NMA has also exercised limited heap leaching on experimental scale and obtained small amounts of U-concentrates, utilized for R & D purposes. However, the exploration activities remained in the preliminary phases and did not succeed to reach either reliable evaluation of the discovered uranium resources or running productive U-exploitation. By the end of the last decade, Egypt has declared the intention to adopt a peaceful program for electric power generation; this implied NMA to implement a twofold plan as described hereafter. Regarding the conventional U-resources, occurring in the Eastern Desert, NMA focus the exploration activities on the younger granites of Pan African type, and the associated inter-mountain basins. The activities will be restricted to the evaluation of U-reserves in at least three of the most promising uranium prospects that still require extensive exploration drilling programs. NMA is now implementing an international bid announcement seeking for partnership of an experienced international firm, to assess the uranium resources in these sites, in addition to receiving relevant IAEA/TC programs. Regarding non-conventional resources, the black sand project is mainly a resource of a titanium and zirconium minerals; however, NMA is now trying to process monazite to obtain mainly Th and minor U by-products. NMA has successfully completed an exploration study and. the Government of Egypt has recently

  18. A Metabolic Biofuel Cell: Conversion of Human Leukocyte Metabolic Activity to Electrical Currents

    Directory of Open Access Journals (Sweden)

    Cui X Tracy

    2011-05-01

    Full Text Available Abstract An investigation of the electrochemical activity of human white blood cells (WBC for biofuel cell (BFC applications is described. WBCs isolated from whole human blood were suspended in PBS and introduced into the anode compartment of a proton exchange membrane (PEM fuel cell. The cathode compartment contained a 50 mM potassium ferricyanide solution. Average current densities between 0.9 and 1.6 μA cm-2 and open circuit potentials (Voc between 83 and 102 mV were obtained, which were both higher than control values. Cyclic voltammetry was used to investigate the electrochemical activity of the activated WBCs in an attempt to elucidate the mechanism of electron transfer between the cells and electrode. Voltammograms were obtained for the WBCs, including peripheral blood mononuclear cells (PBMCs - a lymphocyte-monocyte mixture isolated on a Ficoll gradient, a B lymphoblastoid cell line (BLCL, and two leukemia cell lines, namely K562 and Jurkat. An oxidation peak at about 363 mV vs. SCE for the PMA (phorbol ester activated primary cells, with a notable absence of a reduction peak was observed. Oxidation peaks were not observed for the BLCL, K562 or Jurkat cell lines. HPLC confirmed the release of serotonin (5-HT from the PMA activated primary cells. It is believed that serotonin, among other biochemical species released by the activated cells, contributes to the observed BFC currents.

  19. Testing evolutionary hypotheses for phenotypic divergence using landscape genetics.

    Science.gov (United States)

    Funk, W Chris; Murphy, Melanie A

    2010-02-01

    Understanding the evolutionary causes of phenotypic variation among populations has long been a central theme in evolutionary biology. Several factors can influence phenotypic divergence, including geographic isolation, genetic drift, divergent natural or sexual selection, and phenotypic plasticity. But the relative importance of these factors in generating phenotypic divergence in nature is still a tantalizing and unresolved problem in evolutionary biology. The origin and maintenance of phenotypic divergence is also at the root of many ongoing debates in evolutionary biology, such as the extent to which gene flow constrains adaptive divergence (Garant et al. 2007) and the relative importance of genetic drift, natural selection, and sexual selection in initiating reproductive isolation and speciation (Coyne & Orr 2004). In this issue, Wang & Summers (2010) test the causes of one of the most fantastic examples of phenotypic divergence in nature: colour pattern divergence among populations of the strawberry poison frog (Dendrobates pumilio) in Panama and Costa Rica (Fig. 1). This study provides a beautiful example of the use of the emerging field of landscape genetics to differentiate among hypotheses for phenotypic divergence. Using landscape genetic analyses, Wang & Summers were able to reject the hypotheses that colour pattern divergence is due to isolation-by-distance (IBD) or landscape resistance. Instead, the hypothesis left standing is that colour divergence is due to divergent selection, in turn driving reproductive isolation among populations with different colour morphs. More generally, this study provides a wonderful example of how the emerging field of landscape genetics, which has primarily been applied to questions in conservation and ecology, now plays an essential role in evolutionary research.

  20. Intracellular Ca(2+) release from endoplasmic reticulum regulates slow wave currents and pacemaker activity of interstitial cells of Cajal.

    Science.gov (United States)

    Zhu, Mei Hong; Sung, Tae Sik; O'Driscoll, Kate; Koh, Sang Don; Sanders, Kenton M

    2015-04-15

    Interstitial cells of Cajal (ICC) provide pacemaker activity in gastrointestinal muscles that underlies segmental and peristaltic contractions. ICC generate electrical slow waves that are due to large-amplitude inward currents resulting from anoctamin 1 (ANO1) channels, which are Ca(2+)-activated Cl(-) channels. We investigated the hypothesis that the Ca(2+) responsible for the stochastic activation of ANO1 channels during spontaneous transient inward currents (STICs) and synchronized activation of ANO1 channels during slow wave currents comes from intracellular Ca(2+) stores. ICC, obtained from the small intestine of Kit(+/copGFP) mice, were studied under voltage and current clamp to determine the effects of blocking Ca(2+) uptake into stores and release of Ca(2+) via inositol 1,4,5-trisphosphate (IP3)-dependent and ryanodine-sensitive channels. Cyclocpiazonic acid, thapsigargin, 2-APB, and xestospongin C inhibited STICs and slow wave currents. Ryanodine and tetracaine also inhibited STICs and slow wave currents. Store-active compounds had no direct effects on ANO1 channels expressed in human embryonic kidney-293 cells. Under current clamp, store-active drugs caused significant depolarization of ICC and reduced spontaneous transient depolarizations (STDs). After block of ryanodine receptors with ryanodine and tetracaine, repolarization did not restore STDs. ANO1 expressed in ICC has limited access to cytoplasmic Ca(2+) concentration, suggesting that pacemaker activity depends on Ca(2+) dynamics in restricted microdomains. Our data from studies of isolated ICC differ somewhat from studies on intact muscles and suggest that release of Ca(2+) from both IP3 and ryanodine receptors is important in generating pacemaker activity in ICC. Copyright © 2015 the American Physiological Society.

  1. Intracellular Ca2+ release from endoplasmic reticulum regulates slow wave currents and pacemaker activity of interstitial cells of Cajal

    Science.gov (United States)

    Zhu, Mei Hong; Sung, Tae Sik; O'Driscoll, Kate; Koh, Sang Don

    2015-01-01

    Interstitial cells of Cajal (ICC) provide pacemaker activity in gastrointestinal muscles that underlies segmental and peristaltic contractions. ICC generate electrical slow waves that are due to large-amplitude inward currents resulting from anoctamin 1 (ANO1) channels, which are Ca2+-activated Cl− channels. We investigated the hypothesis that the Ca2+ responsible for the stochastic activation of ANO1 channels during spontaneous transient inward currents (STICs) and synchronized activation of ANO1 channels during slow wave currents comes from intracellular Ca2+ stores. ICC, obtained from the small intestine of Kit+/copGFP mice, were studied under voltage and current clamp to determine the effects of blocking Ca2+ uptake into stores and release of Ca2+ via inositol 1,4,5-trisphosphate (IP3)-dependent and ryanodine-sensitive channels. Cyclocpiazonic acid, thapsigargin, 2-APB, and xestospongin C inhibited STICs and slow wave currents. Ryanodine and tetracaine also inhibited STICs and slow wave currents. Store-active compounds had no direct effects on ANO1 channels expressed in human embryonic kidney-293 cells. Under current clamp, store-active drugs caused significant depolarization of ICC and reduced spontaneous transient depolarizations (STDs). After block of ryanodine receptors with ryanodine and tetracaine, repolarization did not restore STDs. ANO1 expressed in ICC has limited access to cytoplasmic Ca2+ concentration, suggesting that pacemaker activity depends on Ca2+ dynamics in restricted microdomains. Our data from studies of isolated ICC differ somewhat from studies on intact muscles and suggest that release of Ca2+ from both IP3 and ryanodine receptors is important in generating pacemaker activity in ICC. PMID:25631870

  2. A Decentralized Approach to the Formulation of Hypotheses: A Hierarchical Structural Model for a Prion Self-Assembled System

    Science.gov (United States)

    Wang, Mingyang; Zhang, Feifei; Song, Chao; Shi, Pengfei; Zhu, Jin

    2016-07-01

    Innovation in hypotheses is a key transformative driver for scientific development. The conventional centralized hypothesis formulation approach, where a dominant hypothesis is typically derived from a primary phenomenon, can, inevitably, impose restriction on the range of conceivable experiments and legitimate hypotheses, and ultimately impede understanding of the system of interest. We report herein the proposal of a decentralized approach for the formulation of hypotheses, through initial preconception-free phenomenon accumulation and subsequent reticular logical reasoning processes. The two-step approach can provide an unbiased, panoramic view of the system and as such should enable the generation of a set of more coherent and therefore plausible hypotheses. As a proof-of-concept demonstration of the utility of this open-ended approach, a hierarchical model has been developed for a prion self-assembled system, allowing insight into hitherto elusive static and dynamic features associated with this intriguing structure.

  3. Current UNSCEAR Activities

    International Nuclear Information System (INIS)

    Mohamed, G.

    2010-01-01

    UNSCEAR stands for United Nation Scientific Committee of Effects of Atomic Radiation. It has been in service for 55 years. It reports to the General Assembly. Its role is to assess global levels and effects of ionizing radiation and to provide scientific basis UNSCEAR in Africa: Egypt joined UNSCEAR in 1955 while Sudan joined in 1973. UNSCEAR in IRPA-11: Norman Gentner (Canada), the Scientific Secretary from 2001- 2005 gave a presentation about UNSCEAR. It was in Madrid, Spain 2004 UNSCEAR in second IRPA Africa’S Congress: This was in Egypt 2007. Abel Gonzalez (Argentina) who is a Member of UNSCEAR gave two presentations. i.e. a refresher course (UNSCEAR ) and a general lecture about UNSCEAR activities UNSCEAR in IRPA-12: Was held in 2008 and Malcolm Crick (UNSCEAR Scientific secretary) from 2005 gave a lecture entitled „Epistemology of radiation protection status of levels and effects of ionizing radiation.. UNSCEAR at IRPA Egypt workshop was held in Egypt January 2010 and Gomaa presented Malcolm Crick lecture to IRPA-12 to the participants of IRPA Egypt workshop January 2010. UNSCEAR Latest publications: Among the publications are:- UNSCEAR 2006 Report: E ffects of ionizing radiation” 5 UNSCEAR 2008 Report: S ources and effects of ionizing radiation”. The 57 Session of UNSCEAR activities: a. The activities included reporting to the General Assembly on three levels. Part -1: Report on session deliberations Part-2: Scientific Report: Summary of low-dose radiation effects on health Part-3: Response to paragraph 13 of resolution 64/85 b. There were also discussions on some documents which included: -Assessment of levels of radiation from electrical energy production -Uncertainty in radiation risk estimation - Health effects attributable to radiation exposure -Methodology for estimating exposures due to discharges -Summary of radiation effects on health -Improving data collection, analysis and dissemination At the end of the lecture, there was an invitation

  4. Bullying Victimization and Adolescent Self-Harm: Testing Hypotheses from General Strain Theory

    Science.gov (United States)

    Hay, Carter; Meldrum, Ryan

    2010-01-01

    Self-harm is widely recognized as a significant adolescent social problem, and recent research has begun to explore its etiology. Drawing from Agnew's (1992) social psychological strain theory of deviance, this study considers this issue by testing three hypotheses about the effects of traditional and cyber bullying victimization on deliberate…

  5. A comparison of professional-level faculty and student perceptions of active learning: its current use, effectiveness, and barriers.

    Science.gov (United States)

    Miller, Cynthia J; Metz, Michael J

    2014-09-01

    Active learning is an instructional method in which students become engaged participants in the classroom through the use of in-class written exercises, games, problem sets, audience-response systems, debates, class discussions, etc. Despite evidence supporting the effectiveness of active learning strategies, minimal adoption of the technique has occurred in many professional programs. The goal of this study was to compare the perceptions of active learning between students who were exposed to active learning in the classroom (n = 116) and professional-level physiology faculty members (n = 9). Faculty members reported a heavy reliance on lectures and minimal use of educational games and activities, whereas students indicated that they learned best via the activities. A majority of faculty members (89%) had observed active learning in the classroom and predicted favorable effects of the method on student performance and motivation. The main reported barriers by faculty members to the adoption of active learning were a lack of necessary class time, a high comfort level with traditional lectures, and insufficient time to develop materials. Students hypothesized similar obstacles for faculty members but also associated many negative qualities with the traditional lecturers. Despite these barriers, a majority of faculty members (78%) were interested in learning more about the alternative teaching strategy. Both faculty members and students indicated that active learning should occupy portions (29% vs. 40%) of face-to-face class time. Copyright © 2014 The American Physiological Society.

  6. Feeding activity of mussels Mytilus edulis related to near-bed currents and phytoplankton biomass

    DEFF Research Database (Denmark)

    Dolmer, Per

    2000-01-01

    The feeding activity of blue mussels Mytilus edulis was investigated in the field and related to near-bottom current velocities and the phytoplankton biomass in the near-bottom water layers for four days. The body content of Chl-a in mussels and their shell gap size were used as indices...... of filtration activity. During days 1 and 2 the near-bed current velocities were low (1.2-2.1 cm s(-1)), and the near-bed phytoplankton biomass was at the same time lower than near the water surface. Between 44 and 69% of the mussels had closed shells and accumulated only small amounts of Chl-a in the body....... During day 3 and day 4 the near-bed current velocities increased to 6.5 and 3.9 cm s(-1). respectively, and the Chl-a was homogeneously distributed in the water column. Now only 17 and 25% of the mussels had closed valves and they accumulated a larger amount of Chl-a. The actual population filtration...

  7. Na+/K+ pump interacts with the h-current to control bursting activity in central pattern generator neurons of leeches

    Science.gov (United States)

    Kueh, Daniel; Barnett, William H; Cymbalyuk, Gennady S; Calabrese, Ronald L

    2016-01-01

    The dynamics of different ionic currents shape the bursting activity of neurons and networks that control motor output. Despite being ubiquitous in all animal cells, the contribution of the Na+/K+ pump current to such bursting activity has not been well studied. We used monensin, a Na+/H+ antiporter, to examine the role of the pump on the bursting activity of oscillator heart interneurons in leeches. When we stimulated the pump with monensin, the period of these neurons decreased significantly, an effect that was prevented or reversed when the h-current was blocked by Cs+. The decreased period could also occur if the pump was inhibited with strophanthidin or K+-free saline. Our monensin results were reproduced in model, which explains the pump’s contributions to bursting activity based on Na+ dynamics. Our results indicate that a dynamically oscillating pump current that interacts with the h-current can regulate the bursting activity of neurons and networks. DOI: http://dx.doi.org/10.7554/eLife.19322.001 PMID:27588351

  8. Educational Transitions in Israel: A Test of the Industrialization and Credentialism Hypotheses.

    Science.gov (United States)

    Shavit, Yossi; Kraus, Vered

    1990-01-01

    Explores the industrialization and credentialism hypotheses and predictions of educational attainment levels. Finds the effects of the father's education and occupation were stable for those attending school in the 1940s, 1950s, and 1960s. Notes that the effects of ethnicity declined in the transition from primary to secondary school. (NL)

  9. Increased carbon sequestration in a Danish beech forest during 1996-2016: Observations and hypotheses.

    Science.gov (United States)

    Pilegaard, Kim; Ibrom, Andreas

    2017-04-01

    A study of the net exchange of CO2 (NEE) between the atmosphere and a beech forest near Sorø, Denmark, during 14 years (1996-2009) showed that the beech forest acted as an increasing sink of CO2 [1]. A significant increase in gross primary production (GPP) and a smaller and not significant increase in ecosystem respiration (RE) were also found. Thus, the increased NEE was mainly attributed to an increase in GPP. The length of the carbon uptake period (CUP) significantly increased, whereas there was a no increase in the leafed period (LP). This means that the leaves stayed active longer. The increase in the carbon uptake period explained about half of the increasing NEE. The remaining increase was believed to be due to an observed increased uptake capacity of the canopy and increased annual radiation efficiency[2]. The causes for this were hypothesized to be a combination of increase in atmospheric CO2 concentration, higher summer precipitation, and increased availability of N. A higher nitrogen content in the leaves was observed towards the end of the observation period. An updated analysis of the flux data, now including the years 1996-2016, confirms the increasing trend in carbon sequestration of the forest, an increasingly longer growing season, and a significant correlation of NEE and CUP, however, similarly to the first study, the increase in CUP only explains about half of the total increase. Here we investigate three hypotheses for the remaining reasons for the increase: H1: increased canopy nitrogen content H2: carbon dioxide fertilisation H3: increased water availability due to changing precipitation patterns. We describe the multiannual development of canopy photosynthesis capacity with regression analysis and perform sensitivity studies with the canopy model MAESTRA [3] to investigate the above hypotheses. The results will be presented, critically discussed and interpreted with respect to general effects of global climate change and site specific, local

  10. Current limitations and recommendations to improve testing for the environmental assessment of endocrine active substances

    Science.gov (United States)

    Coady, Katherine K.; Biever, Ronald C.; Denslow, Nancy D.; Gross, Melanie; Guiney, Patrick D.; Holbech, Henrik; Karouna-Renier, Natalie K.; Katsiadaki, Ioanna; Krueger, Hank; Levine, Steven L.; Maack, Gerd; Williams, Mike; Wolf, Jeffrey C.; Ankley, Gerald T.

    2017-01-01

    In the present study, existing regulatory frameworks and test systems for assessing potential endocrine active chemicals are described, and associated challenges are discussed, along with proposed approaches to address these challenges. Regulatory frameworks vary somewhat across geographies, but all basically evaluate whether a chemical possesses endocrine activity and whether this activity can result in adverse outcomes either to humans or to the environment. Current test systems include in silico, in vitro, and in vivo techniques focused on detecting potential endocrine activity, and in vivo tests that collect apical data to detect possible adverse effects. These test systems are currently designed to robustly assess endocrine activity and/or adverse effects in the estrogen, androgen, and thyroid hormone signaling pathways; however, there are some limitations of current test systems for evaluating endocrine hazard and risk. These limitations include a lack of certainty regarding: 1) adequately sensitive species and life stages; 2) mechanistic endpoints that are diagnostic for endocrine pathways of concern; and 3) the linkage between mechanistic responses and apical, adverse outcomes. Furthermore, some existing test methods are resource intensive with regard to time, cost, and use of animals. However, based on recent experiences, there are opportunities to improve approaches to and guidance for existing test methods and to reduce uncertainty. For example, in vitro high-throughput screening could be used to prioritize chemicals for testing and provide insights as to the most appropriate assays for characterizing hazard and risk. Other recommendations include adding endpoints for elucidating connections between mechanistic effects and adverse outcomes, identifying potentially sensitive taxa for which test methods currently do not exist, and addressing key endocrine pathways of possible concern in addition to those associated with estrogen, androgen, and thyroid

  11. Feedback from physical activity monitors is not compatible with current recommendations: A recalibration study.

    Science.gov (United States)

    Thompson, Dylan; Batterham, Alan M; Peacock, Oliver J; Western, Max J; Booso, Rahuman

    2016-10-01

    Wearable devices to self-monitor physical activity have become popular with individuals and healthcare practitioners as a route to the prevention of chronic disease. It is not currently possible to reconcile feedback from these devices with activity recommendations because the guidelines refer to the amount of activity required on top of normal lifestyle activities (e.g., 150 minutes of moderate-to-vigorous intensity activity per week over-and-above normal moderate-to-vigorous lifestyle activities). The aim of this study was to recalibrate the feedback from self-monitoring. We pooled data from four studies conducted between 2006 and 2014 in patients and volunteers from the community that included both sophisticated measures of physical activity and 10-year risk for cardiovascular disease and type 2 diabetes (n=305). We determined the amount of moderate-to-vigorous intensity activity that corresponded to FAO/WHO/UNU guidance for a required PAL of 1.75 (Total Energy Expenditure/Basal Metabolic Rate). Our results show that, at the UK median PAL, total moderate-to-vigorous intensity physical activity will be around 735 minutes per week (~11% of waking time). We estimate that a 4% increase in moderate-to-vigorous intensity activity will achieve standardised guidance from FAO/WHO/UNU and will require ~1000 minutes of moderate-to-vigorous intensity activity per week. This study demonstrates that feedback from sophisticated wearable devices is incompatible with current physical activity recommendations. Without adjustment, people will erroneously form the view that they are exceeding recommendations by several fold. A more appropriate target from self-monitoring that accounts for normal moderate-to-vigorous lifestyle activities is ~1000 minutes per week, which represents ~15% of waking time. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Detection of TRPV4 channel current-like activity in Fawn Hooded hypertensive (FHH rat cerebral arterial muscle cells.

    Directory of Open Access Journals (Sweden)

    Debebe Gebremedhin

    Full Text Available The transient receptor potential vallinoid type 4 (TRPV4 is a calcium entry channel known to modulate vascular function by mediating endothelium-dependent vasodilation. The present study investigated if isolated cerebral arterial myocytes of the Fawn Hooded hypertensive (FHH rat, known to display exaggerated KCa channel current activity and impaired myogenic tone, express TRPV4 channels at the transcript and protein level and exhibit TRPV4-like single-channel cationic current activity. Reverse transcription polymerase chain reaction (RT-PCR, Western blot, and immunostaining analysis detected the expression of mRNA transcript and translated protein of TRPV4 channel in FHH rat cerebral arterial myocytes. Patch clamp recording of single-channel current activity identified the presence of a single-channel cationic current with unitary conductance of ~85 pS and ~96 pS at hyperpolarizing and depolarizing potentials, respectively, that was inhibited by the TRPV4 channel antagonist RN 1734 or HC 067074 and activated by the potent TRPV4 channel agonist GSK1016790A. Application of negative pressure via the interior of the patch pipette increased the NPo of the TRPV4-like single-channel cationic current recorded in cell-attached patches at a patch potential of 60 mV that was inhibited by prior application of the TRPV4 channel antagonist RN 1734 or HC 067047. Treatment with the TRPV4 channel agonist GSK1016790A caused concentration-dependent increase in the NPo of KCa single-channel current recorded in cell-attached patches of cerebral arterial myocytes at a patch potential of 40 mV, which was not influenced by pretreatment with the voltage-gated L-type Ca2+ channel blocker nifedipine or the T-type Ca2+ channel blocker Ni2+. These findings demonstrate that FHH rat cerebral arterial myocytes express mRNA transcript and translated protein for TRPV4 channel and display TRPV4-like single-channel cationic current activity that was stretch-sensitive and

  13. A review of active learning approaches to experimental design for uncovering biological networks

    Science.gov (United States)

    2017-01-01

    Various types of biological knowledge describe networks of interactions among elementary entities. For example, transcriptional regulatory networks consist of interactions among proteins and genes. Current knowledge about the exact structure of such networks is highly incomplete, and laboratory experiments that manipulate the entities involved are conducted to test hypotheses about these networks. In recent years, various automated approaches to experiment selection have been proposed. Many of these approaches can be characterized as active machine learning algorithms. Active learning is an iterative process in which a model is learned from data, hypotheses are generated from the model to propose informative experiments, and the experiments yield new data that is used to update the model. This review describes the various models, experiment selection strategies, validation techniques, and successful applications described in the literature; highlights common themes and notable distinctions among methods; and identifies likely directions of future research and open problems in the area. PMID:28570593

  14. About hypotheses and paradigms: exploring the Discreetness-Chance Paradigm.

    Science.gov (United States)

    Kaellis, Eugene

    2006-01-01

    Hypotheses generally conform to paradigms which, over time, change, usually tardily, after they have become increasingly difficult to sustain under the impact of non-conforming evidence and alternative hypotheses, but more important, when they no longer are comfortably ensconced in the surrounding social-economic-political-cultural milieu. It is asserted that this milieu is the most important factor in shaping scientific theorizing. Some examples are cited: the rejection of the evidence that the world orbits around the sun (suspected by Pythagoras) in favor of centuries-long firm adherence to the Ptolemaic geocentric system; the early acceptance of Natural Selection in spite of its tautological essence and only conjectural supporting evidence, because it justified contemporaneous social-political ideologies as typified by, e.g., Spencer and Malthus. Economic, social, and cultural factors are cited as providing the ground, i.e., ideational substrate, for what is cited as the Discreetness-Chance Paradigm (DCP), that has increasingly dominated physics, biology, and medicine for over a century and which invokes small, discrete packets of energy/matter (quanta, genes, microorganisms, aberrant cells) functioning within an environment of statistical, not determined, causality. There is speculation on a possible paradigmatic shift from the DCP, which has fostered the proliferation, parallel with ("splitting") taxonomy, of alleged individual disease entities, their diagnoses, and, when available, their specific remedies, something particularly prominent in, e.g., psychiatry's Diagnostic and Statistical Manual, a codified compendium of alleged mental and behavioral disorders, but evident in any textbook of diagnosis and treatment of physical ailments. This presumed paradigm shift may be reflected in Western medicine, presently increasingly empirical and atomized, towards a growing acceptance of a more generalized, subject-oriented, approach to health and disease, a non

  15. Limits on hypothesizing new quantum numbers

    International Nuclear Information System (INIS)

    Goldstein, G.R.; Moravcsik, M.J.

    1986-01-01

    According to a recent theorem, for a general quantum-mechanical system undergoing a process, one can tell from measurements on this system whether or not it is characterized by a quantum number, the existence of which is unknown to the observer, even though the detecting equipment used by the observer is unable to distinguish among the various possible values of the ''secret'' quantum number and hence always averages over them. The present paper deals with situations in which this averaging is avoided and hence the ''secret'' quantum number remains ''secret.'' This occurs when a new quantum number is hypothesized in such a way that all the past measurements pertain to the system with one and the same value of the ''secret'' quantum number, or when the new quantum number is related to the old ones by a specific dynamical model providing a one-to-one correspondence. In the first of these cases, however, the one and the same state of the ''secret'' quantum number needs to be a nondegenerate one. If it is degenerate, the theorem can again be applied. This last feature provides a tool for experimentally testing symmetry breaking and the reestablishment of symmetries in asymptotic regions. The situation is illustrated on historical examples like isospin and strangeness, as well as on some contemporary schemes involving spaces of higher dimensionality

  16. ASIC-like currents in freshly isolated cerebral artery smooth muscle cells are inhibited by endogenous oxidase activity.

    Science.gov (United States)

    Chung, Wen-Shuo; Farley, Jerry M; Drummond, Heather A

    2011-01-01

    The aim of this study was to determine if VSMC ASIC-like currents are regulated by oxidative state. We used whole-cell patch clamp of isolated mouse cerebral VSMCs to determine if 1) reducing agents, such as DTT and GSH, and 2) inhibition of endogenous oxidase activity from NADPH and Xanthine oxidases potentiate active currents and activate electrically silent currents. Pretreatment with 2 mM DTT or GSH, increased the mean peak amplitude of ASIC-like currents evoked by pH 6.0 from 0.4 ± 0.1 to 14.9 ± 3.6 pA/pF, and from 0.9 ± 0.3 to 11.3 ± 2.4 pA/pF, respectively. Pretreatment with apocynin, a NADPH oxidase inhibitor, mimics the effect of the reducing agents, with the mean peak current amplitude increased from 0.9 ± 0.5 to 7.0 ± 2.6 pA/pF and from 0.5 ± 0.2 to 26.4 ± 6.8 pA/pF by 50 and 200 μM apocynin, respectively. Pretreatment with allopurinol, a xanthine oxidase inhibitor, also potentiates the VSMC ASIC-like activity. These findings suggest that VSMC ASIC-like channels are regulated by oxidative state and may be inhibited by basal endogenous oxidative sources such as NADPH and xanthine oxidase. Copyright © 2011 S. Karger AG, Basel.

  17. Current active and passive smoking among adults living with same sex partners in Spain.

    Science.gov (United States)

    Perales, Jaime; Checa, Irene; Espejo, Begoña

    2017-05-19

    To assess the association between current active and passive tobacco smoking and living with a same-sex partner in Spain. We analysed data from two cross-sectional national surveys of the Spanish population 15 years and older (2011-Encuesta Nacional de Salud en España and 2014-Encuesta Europea de Salud en España). Analyses included only people living with their partner. Associations were calculated using multiple logistic regressions adjusting for gender, social class and age. Current active and passive smoking were significantly associated with living with same sex partners (odds ratio: 2.71 and 2.88), and particularly strong among women. Spanish adults living with same-sex partners are at higher risk of active and passive smoking. This risk varies by gender. Spanish national surveys should include items on sexual orientation for improved data on health disparities. Copyright © 2017 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

  18. Distinguishing 'Higgs' spin hypotheses using γγ and WW* decays

    International Nuclear Information System (INIS)

    Ellis, John; Fok, Ricky; Hwang, Dae Sung; Sanz, Veronica; You, Tevong

    2013-01-01

    The new particle X recently discovered by the ATLAS and CMS Collaborations in searches for the Higgs boson has been observed to decay into γγ, ZZ * and WW * , but its spin and parity, J P , remain a mystery, with J P = 0 + and 2 + being open possibilities. We use PYTHIA and Delphes to simulate an analysis of the angular distribution of gg → X → γγ decays in a full 2012 data set, including realistic background levels. We show that this angular distribution should provide strong discrimination between the possibilities of spin zero and spin two with graviton-like couplings: ∝3 σ if a conservative symmetric interpretation of the log-likelihood ratio (LLR) test statistic is used, and ∝6 σ if a less conservative asymmetric interpretation is used. The WW and ZZ couplings of the Standard Model Higgs boson and of a 2 + particle with graviton-like couplings are both expected to exhibit custodial symmetry. We simulate the present ATLAS and CMS search strategies for X → WW * using PYTHIA and Delphes, and show that their efficiencies in the case of a spin-2 particle with graviton-like couplings are a factor ≅ 1.9 smaller than in the spin-0 case. On the other hand, the ratio of X 2 + → WW * and ZZ * branching ratios is larger than that in the 0 + case by a factor ≅ 1.3. We find that the current ATLAS and CMS results for X → WW * and X → ZZ * decays are compatible with custodial symmetry under both the spin-0 and -2 hypotheses, and that the data expected to become available during 2012 are unlikely to discriminate significantly between these possibilities. (orig.)

  19. Contribution of Field Strength Gradients to the Net Vertical Current of Active Regions

    Science.gov (United States)

    Vemareddy, P.

    2017-12-01

    We examined the contribution of field strength gradients for the degree of net vertical current (NVC) neutralization in active regions (ARs). We used photospheric vector magnetic field observations of AR 11158 obtained by Helioseismic and Magnetic Imager on board SDO and Hinode. The vertical component of the electric current is decomposed into twist and shear terms. The NVC exhibits systematic evolution owing to the presence of the sheared polarity inversion line between rotating and shearing magnetic regions. We found that the sign of shear current distribution is opposite in dominant pixels (60%–65%) to that of twist current distribution, and its time profile bears no systematic trend. This result indicates that the gradient of magnetic field strength contributes to an opposite signed, though smaller in magnitude, current to that contributed by the magnetic field direction in the vertical component of the current. Consequently, the net value of the shear current is negative in both polarity regions, which when added to the net twist current reduces the direct current value in the north (B z > 0) polarity, resulting in a higher degree of NVC neutralization. We conjecture that the observed opposite signs of shear and twist currents are an indication, according to Parker, that the direct volume currents of flux tubes are canceled by their return currents, which are contributed by field strength gradients. Furthermore, with the increase of spatial resolution, we found higher values of twist, shear current distributions. However, the resolution effect is more useful in resolving the field strength gradients, and therefore suggests more contribution from shear current for the degree of NVC neutralization.

  20. Transitionality in addiction: A "temporal continuum" hypotheses involving the aberrant motivation, the hedonic dysregulation, and the aberrant learning.

    Science.gov (United States)

    Patrono, Enrico; Gasbarri, Antonella; Tomaz, Carlos; Nishijo, Hisao

    2016-08-01

    Addiction is a chronic compulsion and relapsing disorder. It involves several brain areas and circuits, which encode vary functions such as reward, motivation, and memory. Drug addiction is defined as a "pathological pattern of use of a substance", characterized by the loss of control on drug-taking-related behaviors, the pursuance of those behaviors even in the presence of negative consequences, and a strong motivated activity to assume substances. Three different theories guide experimental research on drug addiction. Each of these theories consider singles features, such as an aberrant motivation, a hedonic dysregulation, and an aberrant habit learning as the main actor to explain the entire process of the addictive behaviors. The major goal of this study is to present a new hypotheses of transitionality from a controlled use to abuse of addictive substances trough the overview of the three different theories, considering all the single features of each single theory together on the same "temporal continuum" from use to abuse of addictive substances. Recently, it has been suggested that common neural systems may be activated by natural and pharmacological stimuli, raising the hypotheses that binge-eating disorders could be considered as addictive behaviors. The second goal of this study is to present evidences in order to highlight a possible psycho-bio-physiological superimposition between drug and "food addiction". Finally, interesting questions are brought up starting from last findings about a theoretical/psycho-bio-physiological superimposition between drug and "food addiction" and their possibly same transitionality along the same "temporal continuum" from use to abuse of addictive substances in order to investigate new therapeutic strategies based on new therapeutic strategies based on the individual moments characterizing the transition from the voluntary intake of substances to the maladaptive addictive behavior. Copyright © 2016. Published by Elsevier

  1. An automated framework for hypotheses generation using literature

    Directory of Open Access Journals (Sweden)

    Abedi Vida

    2012-08-01

    Full Text Available Abstract Background In bio-medicine, exploratory studies and hypothesis generation often begin with researching existing literature to identify a set of factors and their association with diseases, phenotypes, or biological processes. Many scientists are overwhelmed by the sheer volume of literature on a disease when they plan to generate a new hypothesis or study a biological phenomenon. The situation is even worse for junior investigators who often find it difficult to formulate new hypotheses or, more importantly, corroborate if their hypothesis is consistent with existing literature. It is a daunting task to be abreast with so much being published and also remember all combinations of direct and indirect associations. Fortunately there is a growing trend of using literature mining and knowledge discovery tools in biomedical research. However, there is still a large gap between the huge amount of effort and resources invested in disease research and the little effort in harvesting the published knowledge. The proposed hypothesis generation framework (HGF finds “crisp semantic associations” among entities of interest - that is a step towards bridging such gaps. Methodology The proposed HGF shares similar end goals like the SWAN but are more holistic in nature and was designed and implemented using scalable and efficient computational models of disease-disease interaction. The integration of mapping ontologies with latent semantic analysis is critical in capturing domain specific direct and indirect “crisp” associations, and making assertions about entities (such as disease X is associated with a set of factors Z. Results Pilot studies were performed using two diseases. A comparative analysis of the computed “associations” and “assertions” with curated expert knowledge was performed to validate the results. It was observed that the HGF is able to capture “crisp” direct and indirect associations, and provide knowledge

  2. An automated framework for hypotheses generation using literature.

    Science.gov (United States)

    Abedi, Vida; Zand, Ramin; Yeasin, Mohammed; Faisal, Fazle Elahi

    2012-08-29

    In bio-medicine, exploratory studies and hypothesis generation often begin with researching existing literature to identify a set of factors and their association with diseases, phenotypes, or biological processes. Many scientists are overwhelmed by the sheer volume of literature on a disease when they plan to generate a new hypothesis or study a biological phenomenon. The situation is even worse for junior investigators who often find it difficult to formulate new hypotheses or, more importantly, corroborate if their hypothesis is consistent with existing literature. It is a daunting task to be abreast with so much being published and also remember all combinations of direct and indirect associations. Fortunately there is a growing trend of using literature mining and knowledge discovery tools in biomedical research. However, there is still a large gap between the huge amount of effort and resources invested in disease research and the little effort in harvesting the published knowledge. The proposed hypothesis generation framework (HGF) finds "crisp semantic associations" among entities of interest - that is a step towards bridging such gaps. The proposed HGF shares similar end goals like the SWAN but are more holistic in nature and was designed and implemented using scalable and efficient computational models of disease-disease interaction. The integration of mapping ontologies with latent semantic analysis is critical in capturing domain specific direct and indirect "crisp" associations, and making assertions about entities (such as disease X is associated with a set of factors Z). Pilot studies were performed using two diseases. A comparative analysis of the computed "associations" and "assertions" with curated expert knowledge was performed to validate the results. It was observed that the HGF is able to capture "crisp" direct and indirect associations, and provide knowledge discovery on demand. The proposed framework is fast, efficient, and robust in

  3. Green Compact Temperature Evolution during Current-Activated Tip-Based Sintering (CATS of Nickel

    Directory of Open Access Journals (Sweden)

    Khaled Morsi

    2013-04-01

    Full Text Available Current-activated tip-based sintering (CATS is a novel process where spark plasma sintering conditions are applied through an electrically conducting tip on a locally controlled area on a green powder compact/bed. The localization of electric current in CATS allows for unique temporal and spatial current and temperature distributions within the tip and powder compact. In this paper, special experimental setups were used to monitor the temperature profiles in the tip and at multiple locations on the surface of nickel powder compacts. A variation in the initial green density was found to have a significant effect on the maximum temperature in the tip as well as the temperature distribution across the powder compact. In general, the lowest green density specimens displayed the best conditions for localized densification. The concept of effective current density is introduced and results are discussed in relation to the densification parameter.

  4. Williams Syndrome Hypersociability: A Neuropsychological Study of the Amygdala and Prefrontal Cortex Hypotheses

    Science.gov (United States)

    Capitao, Liliana; Sampaio, Adriana; Fernandez, Montse; Sousa, Nuno; Pinheiro, Ana; Goncalves, Oscar F.

    2011-01-01

    Individuals with Williams syndrome display indiscriminate approach towards strangers. Neuroimaging studies conducted so far have linked this social profile to structural and/or functional abnormalities in WS amygdala and prefrontal cortex. In this study, the neuropsychological hypotheses of amygdala and prefrontal cortex involvement in WS…

  5. Cholinergic Hypofunction in Presbycusis-Related Tinnitus With Cognitive Function Impairment: Emerging Hypotheses.

    Science.gov (United States)

    Ruan, Qingwei; Yu, Zhuowei; Zhang, Weibin; Ruan, Jian; Liu, Chunhui; Zhang, Ruxin

    2018-01-01

    Presbycusis (age-related hearing loss) is a potential risk factor for tinnitus and cognitive deterioration, which result in poor life quality. Presbycusis-related tinnitus with cognitive impairment is a common phenotype in the elderly population. In these individuals, the central auditory system shows similar pathophysiological alterations as those observed in Alzheimer's disease (AD), including cholinergic hypofunction, epileptiform-like network synchronization, chronic inflammation, and reduced GABAergic inhibition and neural plasticity. Observations from experimental rodent models indicate that recovery of cholinergic function can improve memory and other cognitive functions via acetylcholine-mediated GABAergic inhibition enhancement, nicotinic acetylcholine receptor (nAChR)-mediated anti-inflammation, glial activation inhibition and neurovascular protection. The loss of cholinergic innervation of various brain structures may provide a common link between tinnitus seen in presbycusis-related tinnitus and age-related cognitive impairment. We hypothesize a key component of the condition is the withdrawal of cholinergic input to a subtype of GABAergic inhibitory interneuron, neuropeptide Y (NPY) neurogliaform cells. Cholinergic denervation might not only cause the degeneration of NPY neurogliaform cells, but may also result in decreased AChR activation in GABAergic inhibitory interneurons. This, in turn, would lead to reduced GABA release and inhibitory regulation of neural networks. Reduced nAChR-mediated anti-inflammation due to the loss of nicotinic innervation might lead to the transformation of glial cells and release of inflammatory mediators, lowering the buffering of extracellular potassium and glutamate metabolism. Further research will provide evidence for the recovery of cholinergic function with the use of cholinergic input enhancement alone or in combination with other rehabilitative interventions to reestablish inhibitory regulation mechanisms of

  6. Why Be a Shrub? A Basic Model and Hypotheses for the Adaptive Values of a Common Growth Form

    Science.gov (United States)

    Götmark, Frank; Götmark, Elin; Jensen, Anna M.

    2016-01-01

    Shrubs are multi-stemmed short woody plants, more widespread than trees, important in many ecosystems, neglected in ecology compared to herbs and trees, but currently in focus due to their global expansion. We present a novel model based on scaling relationships and four hypotheses to explain the adaptive significance of shrubs, including a review of the literature with a test of one hypothesis. Our model describes advantages for a small shrub compared to a small tree with the same above-ground woody volume, based on larger cross-sectional stem area, larger area of photosynthetic tissue in bark and stem, larger vascular cambium area, larger epidermis (bark) area, and larger area for sprouting, and faster production of twigs and canopy. These components form our Hypothesis 1 that predicts higher growth rate for a small shrub than a small tree. This prediction was supported by available relevant empirical studies (14 publications). Further, a shrub will produce seeds faster than a tree (Hypothesis 2), multiple stems in shrubs insure future survival and growth if one or more stems die (Hypothesis 3), and three structural traits of short shrub stems improve survival compared to tall tree stems (Hypothesis 4)—all hypotheses have some empirical support. Multi-stemmed trees may be distinguished from shrubs by more upright stems, reducing bending moment. Improved understanding of shrubs can clarify their recent expansion on savannas, grasslands, and alpine heaths. More experiments and other empirical studies, followed by more elaborate models, are needed to understand why the shrub growth form is successful in many habitats. PMID:27507981

  7. Active current management for four-rail railguns

    International Nuclear Information System (INIS)

    Beno, J.H.; Weldon, W.F.

    1991-01-01

    In this paper a system of auxiliary conductors designed to reduce current density peaks in railgun rails for four-rail, round-bore railguns is described. The effects on rail current density and projectile force are discussed. Railgun cross-sectional designs are presented for round-bore, four-rail railguns which operate at lower peak current densities and develop greater projectile forces than conventional two-rail, round-bore railguns

  8. Coping with the Stigma of Mental Illness: Empirically-Grounded Hypotheses from Computer Simulations

    Science.gov (United States)

    Kroska, Amy; Har, Sarah K.

    2011-01-01

    This research demonstrates how affect control theory and its computer program, "Interact", can be used to develop empirically-grounded hypotheses regarding the connection between cultural labels and behaviors. Our demonstration focuses on propositions in the modified labeling theory of mental illness. According to the MLT, negative societal…

  9. The Outwardly Rectifying Current of Layer 5 Neocortical Neurons that was Originally Identified as "Non-Specific Cationic" Is Essentially a Potassium Current.

    Directory of Open Access Journals (Sweden)

    Omer Revah

    Full Text Available In whole-cell patch clamp recordings from layer 5 neocortical neurons, blockade of voltage gated sodium and calcium channels leaves a cesium current that is outward rectifying. This current was originally identified as a "non-specific cationic current", and subsequently it was hypothesized that it is mediated by TRP channels. In order to test this hypothesis, we used fluorescence imaging of intracellular sodium and calcium indicators, and found no evidence to suggest that it is associated with influx of either of these ions to the cell body or dendrites. Moreover, the current is still prominent in neurons from TRPC1-/- and TRPC5-/- mice. The effects on the current of various blocking agents, and especially its sensitivity to intracellular tetraethylammonium, suggest that it is not a non-specific cationic current, but rather that it is generated by cesium-permeable delayed rectifier potassium channels.

  10. From themes to hypotheses: following up with quantitative methods.

    Science.gov (United States)

    Morgan, David L

    2015-06-01

    One important category of mixed-methods research designs consists of quantitative studies that follow up on qualitative research. In this case, the themes that serve as the results from the qualitative methods generate hypotheses for testing through the quantitative methods. That process requires operationalization to translate the concepts from the qualitative themes into quantitative variables. This article illustrates these procedures with examples that range from simple operationalization to the evaluation of complex models. It concludes with an argument for not only following up qualitative work with quantitative studies but also the reverse, and doing so by going beyond integrating methods within single projects to include broader mutual attention from qualitative and quantitative researchers who work in the same field. © The Author(s) 2015.

  11. Pharmacological activation of rapid delayed rectifier potassium current suppresses bradycardia-induced triggered activity in the isolated guinea pig heart

    DEFF Research Database (Denmark)

    Hansen, Rie Schultz; Olesen, Søren-Peter; Grunnet, Morten

    2007-01-01

    arrhythmias. We present here data that support that NS3623 affects native I(Kr) and report the effects that activating this potassium current have in the intact guinea pig heart. In Langendorff-perfused hearts, the compound showed a concentration-dependent shortening of action potential duration, which...

  12. Parameter design and performance simulation of a 10 kV voltage compensation type active superconducting fault current limiter

    International Nuclear Information System (INIS)

    Chen, L.; Tang, Y.J.; Song, M.; Shi, J.; Ren, L.

    2013-01-01

    Highlights: •For a practical 10 kV system, the 10 kV active SFCL’s basic parameters are designed. •Under different fault conditions, the 10 kV active SFCL’s performances are simulated. •The designed 10 kV active SFCL’s engineering feasibility is discussed preliminarily. -- Abstract: Since the introduction of superconducting fault current limiter (SFCL) into electrical distribution system may be a good choice with economy and practicability, the parameter design and current-limiting characteristics of a 10 kV voltage compensation type active SFCL are studied in this paper. Firstly, the SFCL’s circuit structure and operation principle are presented. Then, taking a practical 10 kV distribution system as its application object, the SFCL’s basic parameters are designed to meet the system requirements. Further, using MATLAB, the detailed current-limiting performances of the 10 kV active SFCL are simulated under different fault conditions. The simulation results show that the active SFCL can deal well with the faults, and the parameter design’s suitability can be testified. At the end, in view of the engineering feasibility of the 10 kV active SFCL, some preliminary discussions are carried out

  13. Influence of active dendritic currents on input-output processing in spinal motoneurons in vivo.

    Science.gov (United States)

    Lee, R H; Kuo, J J; Jiang, M C; Heckman, C J

    2003-01-01

    The extensive dendritic tree of the adult spinal motoneuron generates a powerful persistent inward current (PIC). We investigated how this dendritic PIC influenced conversion of synaptic input to rhythmic firing. A linearly increasing, predominantly excitatory synaptic input was generated in triceps ankle extensor motoneurons by slow stretch (duration: 2-10 s) of the Achilles tendon in the decerebrate cat preparation. The firing pattern evoked by stretch was measured by injecting a steady current to depolarize the cell to threshold for firing. The effective synaptic current (I(N), the net synaptic current reaching the soma of the cell) evoked by stretch was measured during voltage clamp. Hyperpolarized holding potentials were used to minimize the activation of the dendritic PIC and thus estimate stretch-evoked I(N) for a passive dendritic tree (I(N,PASS)). Depolarized holding potentials that approximated the average membrane potential during rhythmic firing allowed strong activation of the dendritic PIC and thus resulted in marked enhancement of the total stretch-evoked I(N) (I(N,TOT)). The net effect of the dendritic PIC on the generation of rhythmic firing was assessed by plotting stretch-evoked firing (strong PIC activation) versus stretch-evoked I(N,PASS) (minimal PIC activation). The gain of this input-output function for the neuron (I-O(N)) was found to be ~2.7 times as high as for the standard injected frequency current (F-I) function in low-input conductance neurons. However, about halfway through the stretch, firing rate tended to become constant, resulting in a sharp saturation in I-O(N) that was not present in F-I. In addition, the gain of I-O(N) decreased sharply with increasing input conductance, resulting in much lower stretch-evoked firing rates in high-input conductance cells. All three of these phenomena (high initial gain, saturation, and differences in low- and high-input conductance cells) were also readily apparent in the differences between

  14. Why are there lasting effects from exposure to stress during development? An analysis of current models of early stress.

    Science.gov (United States)

    Chaby, Lauren E

    2016-10-01

    The potential for stressful experiences in early life to cause lasting changes in phenotype is well documented, but the functional and evolutionary context of these changes is not well understood. Many hypotheses have been proposed to explain the role of lasting effects of stress exposure during gestation and early development; the purpose of this review is to discuss these hypotheses in the context of human and non-human animal research in the last three decades in order to (i) further dialogues between those approaching early stress from biomedical and evolutionary/ecological perspectives, (ii) outline strengths and limitations of current hypotheses, with respect to species and context-specific effects of exposure to stress in early development, and (iii) address recent evidence suggesting that stress in early development can have beneficial effects in adulthood. It is suggested that the hypotheses discussed are not mutually exclusive, but the applicability of each hypothesis will depend upon the environmental conditions and stability a species, or perhaps even an individual, experiences in their lifetime. Potential investigations to clarify applications of the current hypotheses are discussed, including longitudinal studies that span multiple developmental stages and investigations of species where measures of fitness are possible. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Search for active-sterile neutrino mixing using neutral-current interactions in NOvA

    Science.gov (United States)

    Adamson, P.; Aliaga, L.; Ambrose, D.; Anfimov, N.; Antoshkin, A.; Arrieta-Diaz, E.; Augsten, K.; Aurisano, A.; Backhouse, C.; Baird, M.; Bambah, B. A.; Bays, K.; Behera, B.; Bending, S.; Bernstein, R.; Bhatnagar, V.; Bhuyan, B.; Bian, J.; Blackburn, T.; Bolshakova, A.; Bromberg, C.; Brown, J.; Brunetti, G.; Buchanan, N.; Butkevich, A.; Bychkov, V.; Campbell, M.; Catano-Mur, E.; Childress, S.; Choudhary, B. C.; Chowdhury, B.; Coan, T. E.; Coelho, J. A. B.; Colo, M.; Cooper, J.; Corwin, L.; Cremonesi, L.; Cronin-Hennessy, D.; Davies, G. S.; Davies, J. P.; Derwent, P. F.; Dharmapalan, R.; Ding, P.; Djurcic, Z.; Dukes, E. C.; Duyang, H.; Edayath, S.; Ehrlich, R.; Feldman, G. J.; Frank, M. J.; Gabrielyan, M.; Gallagher, H. R.; Germani, S.; Ghosh, T.; Giri, A.; Gomes, R. A.; Goodman, M. C.; Grichine, V.; Groh, M.; Group, R.; Grover, D.; Guo, B.; Habig, A.; Hartnell, J.; Hatcher, R.; Hatzikoutelis, A.; Heller, K.; Himmel, A.; Holin, A.; Howard, B.; Hylen, J.; Jediny, F.; Judah, M.; Kafka, G. K.; Kalra, D.; Kasahara, S. M. S.; Kasetti, S.; Keloth, R.; Kolupaeva, L.; Kotelnikov, S.; Kourbanis, I.; Kreymer, A.; Kumar, A.; Kurbanov, S.; Lackey, T.; Lang, K.; Lee, W. M.; Lin, S.; Lokajicek, M.; Lozier, J.; Luchuk, S.; Maan, K.; Magill, S.; Mann, W. A.; Marshak, M. L.; Matera, K.; Matveev, V.; Méndez, D. P.; Messier, M. D.; Meyer, H.; Miao, T.; Miller, W. H.; Mishra, S. R.; Mohanta, R.; Moren, A.; Mualem, L.; Muether, M.; Mufson, S.; Murphy, R.; Musser, J.; Nelson, J. K.; Nichol, R.; Niner, E.; Norman, A.; Nosek, T.; Oksuzian, Y.; Olshevskiy, A.; Olson, T.; Paley, J.; Patterson, R. B.; Pawloski, G.; Pershey, D.; Petrova, O.; Petti, R.; Phan-Budd, S.; Plunkett, R. K.; Poling, R.; Potukuchi, B.; Principato, C.; Psihas, F.; Radovic, A.; Rameika, R. A.; Rebel, B.; Reed, B.; Rocco, D.; Rojas, P.; Ryabov, V.; Sachdev, K.; Sail, P.; Samoylov, O.; Sanchez, M. C.; Schroeter, R.; Sepulveda-Quiroz, J.; Shanahan, P.; Sheshukov, A.; Singh, J.; Singh, J.; Singh, P.; Singh, V.; Smolik, J.; Solomey, N.; Song, E.; Sousa, A.; Soustruznik, K.; Strait, M.; Suter, L.; Talaga, R. L.; Tas, P.; Thayyullathil, R. B.; Thomas, J.; Tian, X.; Tognini, S. C.; Tripathi, J.; Tsaris, A.; Urheim, J.; Vahle, P.; Vasel, J.; Vinton, L.; Vold, A.; Vrba, T.; Wang, B.; Wetstein, M.; Whittington, D.; Wojcicki, S. G.; Wolcott, J.; Yadav, N.; Yang, S.; Zalesak, J.; Zamorano, B.; Zwaska, R.; NOvA Collaboration

    2017-10-01

    We report results from the first search for sterile neutrinos mixing with active neutrinos through a reduction in the rate of neutral-current interactions over a baseline of 810 km between the NOvA detectors. Analyzing a 14-kton detector equivalent exposure of 6.05 ×1020 protons-on-target in the NuMI beam at Fermilab, we observe 95 neutral-current candidates at the Far Detector compared with 83.5 ±9.7 (stat ) ±9.4 (syst ) events predicted assuming mixing only occurs between active neutrino species. No evidence for νμ→νs transitions is found. Interpreting these results within a 3 +1 model, we place constraints on the mixing angles θ24<20.8 ° and θ34<31.2 ° at the 90% C.L. for 0.05 eV2≤Δ m412≤0.5 eV2 , the range of mass splittings that produce no significant oscillations over the Near Detector baseline.

  16. Non-invasive brain stimulation for Parkinson's disease: Current concepts and outlook 2015.

    Science.gov (United States)

    Benninger, David H; Hallett, Mark

    2015-01-01

    In advanced Parkinson's disease (PD), the emergence of symptoms refractory to conventional therapy poses a therapeutic challenge. The success of deep brain stimulation (DBS) and advances in the understanding of the pathophysiology of PD have raised interest in non-invasive brain stimulation as an alternative therapeutic tool. The rationale for its use draws from the concept that reversing abnormalities in brain activity and physiology thought to cause the clinical deficits may restore normal functioning. Currently the best evidence in support of this concept comes from DBS, which improves motor deficits, and modulates brain activity and motor cortex physiology, though whether a causal interaction exists remains largely undetermined. Most trials of non-invasive brain stimulation in PD have applied repetitive transcranial magnetic stimulation (rTMS) targeting the primary motor cortex and cortical areas of the motor circuit. Published studies suggest a possible therapeutic potential of rTMS and transcranial direct current stimulation (tDCS), but clinical effects so far have been small and negligible regarding functional independence and quality of life. Approaches to potentiate the efficacy of rTMS, including increasing stimulation intensity and novel stimulation parameters, derive their rationale from studies of brain physiology. These novel parameters simulate normal firing patterns or act on the hypothesized role of oscillatory activity in the motor cortex and basal ganglia in motor control. There may also be diagnostic potential of TMS in characterizing individual traits for personalized medicine.

  17. New Vehicle Detection Method with Aspect Ratio Estimation for Hypothesized Windows

    Directory of Open Access Journals (Sweden)

    Jisu Kim

    2015-12-01

    Full Text Available All kinds of vehicles have different ratios of width to height, which are called the aspect ratios. Most previous works, however, use a fixed aspect ratio for vehicle detection (VD. The use of a fixed vehicle aspect ratio for VD degrades the performance. Thus, the estimation of a vehicle aspect ratio is an important part of robust VD. Taking this idea into account, a new on-road vehicle detection system is proposed in this paper. The proposed method estimates the aspect ratio of the hypothesized windows to improve the VD performance. Our proposed method uses an Aggregate Channel Feature (ACF and a support vector machine (SVM to verify the hypothesized windows with the estimated aspect ratio. The contribution of this paper is threefold. First, the estimation of vehicle aspect ratio is inserted between the HG (hypothesis generation and the HV (hypothesis verification. Second, a simple HG method named a signed horizontal edge map is proposed to speed up VD. Third, a new measure is proposed to represent the overlapping ratio between the ground truth and the detection results. This new measure is used to show that the proposed method is better than previous works in terms of robust VD. Finally, the Pittsburgh dataset is used to verify the performance of the proposed method.

  18. Delinquency and Peer Acceptance in Adolescence: A Within-Person Test of Moffitt's Hypotheses

    Science.gov (United States)

    Rulison, Kelly L.; Kreager, Derek A.; Osgood, D. Wayne

    2014-01-01

    We tested 2 hypotheses derived from Moffitt's (1993) taxonomic theory of antisocial behavior, both of which are central to her explanation for the rise in delinquency during adolescence. We tested whether persistently delinquent individuals become more accepted by their peers during adolescence and whether individuals who abstain from delinquent…

  19. Performance-Enhanced Activated Carbon Electrodes for Supercapacitors Combining Both Graphene-Modified Current Collectors and Graphene Conductive Additive

    Science.gov (United States)

    Wang, Rubing; Qian, Yuting; Li, Weiwei; Zhu, Shoupu; Liu, Fengkui; Guo, Yufen; Chen, Mingliang; Li, Qi; Liu, Liwei

    2018-01-01

    Graphene has been widely used in the active material, conductive agent, binder or current collector for supercapacitors, due to its large specific surface area, high conductivity, and electron mobility. However, works simultaneously employing graphene as conductive agent and current collector were rarely reported. Here, we report improved activated carbon (AC) electrodes (AC@G@NiF/G) simultaneously combining chemical vapor deposition (CVD) graphene-modified nickel foams (NiF/Gs) current collectors and high quality few-layer graphene conductive additive instead of carbon black (CB). The synergistic effect of NiF/Gs and graphene additive makes the performances of AC@G@NiF/G electrodes superior to those of electrodes with CB or with nickel foam current collectors. The performances of AC@G@NiF/G electrodes show that for the few-layer graphene addition exists an optimum value around 5 wt %, rather than a larger addition of graphene, works out better. A symmetric supercapacitor assembled by AC@G@NiF/G electrodes exhibits excellent cycling stability. We attribute improved performances to graphene-enhanced conductivity of electrode materials and NiF/Gs with 3D graphene conductive network and lower oxidation, largely improving the electrical contact between active materials and current collectors. PMID:29762528

  20. Performance-Enhanced Activated Carbon Electrodes for Supercapacitors Combining Both Graphene-Modified Current Collectors and Graphene Conductive Additive.

    Science.gov (United States)

    Wang, Rubing; Qian, Yuting; Li, Weiwei; Zhu, Shoupu; Liu, Fengkui; Guo, Yufen; Chen, Mingliang; Li, Qi; Liu, Liwei

    2018-05-15

    Graphene has been widely used in the active material, conductive agent, binder or current collector for supercapacitors, due to its large specific surface area, high conductivity, and electron mobility. However, works simultaneously employing graphene as conductive agent and current collector were rarely reported. Here, we report improved activated carbon (AC) electrodes (AC@G@NiF/G) simultaneously combining chemical vapor deposition (CVD) graphene-modified nickel foams (NiF/Gs) current collectors and high quality few-layer graphene conductive additive instead of carbon black (CB). The synergistic effect of NiF/Gs and graphene additive makes the performances of AC@G@NiF/G electrodes superior to those of electrodes with CB or with nickel foam current collectors. The performances of AC@G@NiF/G electrodes show that for the few-layer graphene addition exists an optimum value around 5 wt %, rather than a larger addition of graphene, works out better. A symmetric supercapacitor assembled by AC@G@NiF/G electrodes exhibits excellent cycling stability. We attribute improved performances to graphene-enhanced conductivity of electrode materials and NiF/Gs with 3D graphene conductive network and lower oxidation, largely improving the electrical contact between active materials and current collectors.

  1. Exploration of miRNA families for hypotheses generation.

    KAUST Repository

    Kamanu, T.K.

    2013-10-15

    Technological improvements have resulted in increased discovery of new microRNAs (miRNAs) and refinement and enrichment of existing miRNA families. miRNA families are important because they suggest a common sequence or structure configuration in sets of genes that hint to a shared function. Exploratory tools to enhance investigation of characteristics of miRNA families and the functions of family-specific miRNA genes are lacking. We have developed, miRNAVISA, a user-friendly web-based tool that allows customized interrogation and comparisons of miRNA families for hypotheses generation, and comparison of per-species chromosomal distribution of miRNA genes in different families. This study illustrates hypothesis generation using miRNAVISA in seven species. Our results unveil a subclass of miRNAs that may be regulated by genomic imprinting, and also suggest that some miRNA families may be species-specific, as well as chromosome- and/or strand-specific.

  2. Induction of self awareness in dreams through frontal low current stimulation of gamma activity.

    Science.gov (United States)

    Voss, Ursula; Holzmann, Romain; Hobson, Allan; Paulus, Walter; Koppehele-Gossel, Judith; Klimke, Ansgar; Nitsche, Michael A

    2014-06-01

    Recent findings link fronto-temporal gamma electroencephalographic (EEG) activity to conscious awareness in dreams, but a causal relationship has not yet been established. We found that current stimulation in the lower gamma band during REM sleep influences ongoing brain activity and induces self-reflective awareness in dreams. Other stimulation frequencies were not effective, suggesting that higher order consciousness is indeed related to synchronous oscillations around 25 and 40 Hz.

  3. Enhanced Stability of Capacitor-Current Feedback Active Damping for LCL-Filtered Grid Converters

    DEFF Research Database (Denmark)

    Xin, Zhen; Wang, Xiongfei; Loh, Poh Chiang

    2015-01-01

    The proportional capacitor-current feedback active damping method has been widely used to suppress the LCL-filter resonance. However, the time delay in the damping control loop may lead to non-minimum phase or even unstable responses when the resonance frequency varies in a wide range. To improve...

  4. A statistical study of current-sheet formation above solar active regions based on selforganized criticality

    Science.gov (United States)

    Dimitropoulou, M.; Isliker, H.; Vlahos, L.; Georgoulis, M.; Anastasiadis, A.; Toutountzi, A.

    2013-09-01

    We treat flaring solar active regions as physical systems having reached the self-organized critical state. Their evolving magnetic configurations in the low corona may satisfy an instability criterion, related to the excession of a specific threshold in the curl of the magnetic field. This imposed instability criterion implies an almost zero resistivity everywhere in the solar corona, except in regions where magnetic-field discontinuities and. hence, local currents, reach the critical value. In these areas, current-driven instabilities enhance the resistivity by many orders of magnitude forming structures which efficiently accelerate charged particles. Simulating the formation of such structures (thought of as current sheets) via a refined SOC cellular-automaton model provides interesting information regarding their statistical properties. It is shown that the current density in such unstable regions follows power-law scaling. Furthermore, the size distribution of the produced current sheets is best fitted by power laws, whereas their formation probability is investigated against the photospheric magnetic configuration (e.g. Polarity Inversion Lines, Plage). The average fractal dimension of the produced current sheets is deduced depending on the selected critical threshold. The above-mentioned statistical description of intermittent electric field structures can be used by collisional relativistic test particle simulations, aiming to interpret particle acceleration in flaring active regions and in strongly turbulent media in astrophysical plasmas. The above work is supported by the Hellenic National Space Weather Research Network (HNSWRN) via the THALIS Programme.

  5. Political market orientation and strategic party postures: Some hypotheses regarding profiles and relationship strengths

    DEFF Research Database (Denmark)

    Ormrod, Robert P.; Henneberg, Stephan C. M.

    2007-01-01

    an integrated construct of political marketing strategy which is exemplified by the derivation of hypotheses of the relationships between organizational stances on the one hand, and attitudinal and behavioural aspects of political market orientation on the other. We propose two levels of hypotheses: Firstly......Recently, the areas of strategic political marketing as well as political market orientation have been the subject of several conceptual articles (e.g., Henneberg 2006a; O'Cass 1996; Ormrod 2005, 2007). These have laid the theoretical foundations for further empirical work (e.g., Henneberg 2006b; O......'Cass 1996, 2001a, 2001b; Ormrod et al. 2007; Ormrod and Henneberg 2008 forthcoming). However, despite the close conceptual relatedness between some of these concepts they have yet to be integrated to provide a more nuanced picture which researchers but also political marketing practitioners can utilise...

  6. Skin stem cell hypotheses and long term clone survival--explored using agent-based modelling.

    Science.gov (United States)

    Li, X; Upadhyay, A K; Bullock, A J; Dicolandrea, T; Xu, J; Binder, R L; Robinson, M K; Finlay, D R; Mills, K J; Bascom, C C; Kelling, C K; Isfort, R J; Haycock, J W; MacNeil, S; Smallwood, R H

    2013-01-01

    Epithelial renewal in skin is achieved by the constant turnover and differentiation of keratinocytes. Three popular hypotheses have been proposed to explain basal keratinocyte regeneration and epidermal homeostasis: 1) asymmetric division (stem-transit amplifying cell); 2) populational asymmetry (progenitor cell with stochastic fate); and 3) populational asymmetry with stem cells. In this study, we investigated lineage dynamics using these hypotheses with a 3D agent-based model of the epidermis. The model simulated the growth and maintenance of the epidermis over three years. The offspring of each proliferative cell was traced. While all lineages were preserved in asymmetric division, the vast majority were lost when assuming populational asymmetry. The third hypothesis provided the most reliable mechanism for self-renewal by preserving genetic heterogeneity in quiescent stem cells, and also inherent mechanisms for skin ageing and the accumulation of genetic mutation.

  7. As the climatic disasters came. Hydrogen world view contra inflation of hypotheses; Als die Klimakatastrophen kamen. Wasserstoff-Weltbild kontra Hypothesen-Inflation

    Energy Technology Data Exchange (ETDEWEB)

    Gottfried, Rudolf J.

    2009-07-01

    The author of the contribution under consideration addresses to all persons which are interested scientifically and also are ready for leaving the well-trodden paths of conventional conceptions occasionally if it is shown that the paths mislead when continuing. In particular, here it is a matter of the controversy of the hydrogen conception of the world against hypothesis inflation. This book does not set up new hypotheses which are arranged in the numerously existing hypotheses according to the picture of the world. It is time to deliver the secured facts from the crusts of rigid hypotheses in order to look for new realizations without prejudices and in order to arrange the hypotheses meaningfully.

  8. Mixed Stimulus-Induced Mode Selection in Neural Activity Driven by High and Low Frequency Current under Electromagnetic Radiation

    Directory of Open Access Journals (Sweden)

    Lulu Lu

    2017-01-01

    Full Text Available The electrical activities of neurons are dependent on the complex electrophysiological condition in neuronal system, the three-variable Hindmarsh-Rose (HR neuron model is improved to describe the dynamical behaviors of neuronal activities with electromagnetic induction being considered, and the mode transition of electrical activities in neuron is detected when external electromagnetic radiation is imposed on the neuron. In this paper, different types of electrical stimulus impended with a high-low frequency current are imposed on new HR neuron model, and mixed stimulus-induced mode selection in neural activity is discussed in detail. It is found that mode selection of electrical activities stimulated by high-low frequency current, which also changes the excitability of neuron, can be triggered owing to adding the Gaussian white noise. Meanwhile, the mode selection of the neuron electrical activity is much dependent on the amplitude B of the high frequency current under the same noise intensity, and the high frequency response is selected preferentially by applying appropriate parameters and noise intensity. Our results provide insights into the transmission of complex signals in nerve system, which is valuable in engineering prospective applications such as information encoding.

  9. Cholinergic Hypofunction in Presbycusis-Related Tinnitus With Cognitive Function Impairment: Emerging Hypotheses

    Directory of Open Access Journals (Sweden)

    Qingwei Ruan

    2018-04-01

    Full Text Available Presbycusis (age-related hearing loss is a potential risk factor for tinnitus and cognitive deterioration, which result in poor life quality. Presbycusis-related tinnitus with cognitive impairment is a common phenotype in the elderly population. In these individuals, the central auditory system shows similar pathophysiological alterations as those observed in Alzheimer’s disease (AD, including cholinergic hypofunction, epileptiform-like network synchronization, chronic inflammation, and reduced GABAergic inhibition and neural plasticity. Observations from experimental rodent models indicate that recovery of cholinergic function can improve memory and other cognitive functions via acetylcholine-mediated GABAergic inhibition enhancement, nicotinic acetylcholine receptor (nAChR-mediated anti-inflammation, glial activation inhibition and neurovascular protection. The loss of cholinergic innervation of various brain structures may provide a common link between tinnitus seen in presbycusis-related tinnitus and age-related cognitive impairment. We hypothesize a key component of the condition is the withdrawal of cholinergic input to a subtype of GABAergic inhibitory interneuron, neuropeptide Y (NPY neurogliaform cells. Cholinergic denervation might not only cause the degeneration of NPY neurogliaform cells, but may also result in decreased AChR activation in GABAergic inhibitory interneurons. This, in turn, would lead to reduced GABA release and inhibitory regulation of neural networks. Reduced nAChR-mediated anti-inflammation due to the loss of nicotinic innervation might lead to the transformation of glial cells and release of inflammatory mediators, lowering the buffering of extracellular potassium and glutamate metabolism. Further research will provide evidence for the recovery of cholinergic function with the use of cholinergic input enhancement alone or in combination with other rehabilitative interventions to reestablish inhibitory regulation

  10. Analysis and design of grid-current-feedback active damping for LCL resonance in grid-connected voltage source converters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    This paper investigates the active damping of LCL-filter resonance within single-loop grid current control of grid-connected voltage source converters. First, the basic analysis in the continuous s-domain reveals that the grid-current-feedback active damping forms a virtual impedance across...... in a digital control system. The instability induced by the negative virtual resistance, which is commonly experienced in the feedback-type active damping, can thus be avoided. A systematic design method of the highpass filter is also proposed by the help of root locus analysis in the discrete z-domain. Lastly...

  11. On Active Current Selection for Lagrangian Profilers

    Directory of Open Access Journals (Sweden)

    J. Jouffroy

    2013-01-01

    Full Text Available Autonomous Lagrangian profilers are now widely used as measurement and monitoring platforms, notably in observation programs as Argo. In a typical mode of operation, the profilers drift passively at their parking depthbefore making a vertical profile to go back to the surface. This paperpresents simple and computationally-efficient control strategies to activelyselect and use ocean currents so that a profiler can autonomously reach adesired destination. After briefly presenting a typical profiler andpossible mechanical modifications for a coastal environment, we introducesimple mathematical models for the profiler and the currents it will use. Wethen present simple feedback controllers that, using the direction of thecurrents and taking into account the configuration of the environment(coastal or deep-sea, is able to steer the profiler to any desiredhorizontal location. To illustrate the approach, a few results are presentedusing both simulated currents and real current velocity profiles from theNorth Sea.

  12. 77 FR 37063 - Agency Information Collection Activities: Extension, Without Change, of a Currently Approved...

    Science.gov (United States)

    2012-06-20

    ... information technology, e.g., permitting electronic submission of responses. Overview of This Information... additional information should be directed to: John Ramsay, Program (Forms) Manager, U.S. Immigration and... Information Collection Activities: Extension, Without Change, of a Currently Approved Collection; Comment...

  13. Current Activities and Plans of ICRP

    International Nuclear Information System (INIS)

    Valentin, J.

    2001-01-01

    Full text: The International Commission on Radiological Protection (ICRP) is established to advance for the public benefit the science of (ionising) radiation protection by providing recommendations and guidance, aiming at an appropriate standard of protection without unduly limiting beneficial practices. The Main Commission of ICRP recently launched a Task Group on new, consolidated Recommendations, based on world-wide consultations through IRPA on concepts proposed by the ICRP Chairman. It has also established a Task Group on protection of the environment, to review the Commission's policy that if humans are protected to the degree thought necessary, then other species are adequately protected. Task Groups of Committee 1 (Radiation effects) are planning reports on cancer risks at low doses; radiation effects on the embryo/fetus; and radiation quality effects. Committee 2 (Doses from radiation exposures) has Task Groups on internal dosimetry and on dose calculations, currently drafting reports on embryo/fetus dose coefficients; application of the ICRP lung model, and radionuclide transfer to breast milk. Task Groups on the human alimentary tract and on reference man are also preparing reports. Committee 3 (Protection in medicine) has initiated a series of practical reports on pregnancy and medical radiation; interventional radiology; accident prevention in radiotherapy; computed tomography; and release of patients after therapy with unsealed sources; as well as its series on new radiopharmaceuticals. Committee 4 (Application of ICRP recommendations) is providing input to the Main Commission Task Groups and is proposing a Task Group on radiation in space flight. Information about ICRP activities is available at www.icrp.org. (author)

  14. "On Clocks and Clouds:" Confirming and Interpreting Climate Models as Scientific Hypotheses (Invited)

    Science.gov (United States)

    Donner, L.

    2009-12-01

    The certainty of climate change projected under various scenarios of emissions using general circulation models is an issue of vast societal importance. Unlike numerical weather prediction, a problem to which general circulation models are also applied, projected climate changes usually lie outside of the range of external forcings for which the models generating these changes have been directly evaluated. This presentation views climate models as complex scientific hypotheses and thereby frames these models within a well-defined process of both advancing scientific knowledge and recognizing its limitations. Karl Popper's Logik der Forschung (The Logic of Scientific Discovery, 1934) and 1965 essay “On Clocks and Clouds” capture well the methodologies and challenges associated with constructing climate models. Indeed, the process of a problem situation generating tentative theories, refined by error elimination, characterizes aptly the routine of general circulation model development. Limitations on certainty arise from the distinction Popper perceived in types of natural processes, which he exemplified by clocks, capable of exact measurement, and clouds, subject only to statistical approximation. Remarkably, the representation of clouds in general circulation models remains the key uncertainty in understanding atmospheric aspects of climate change. The asymmetry of hypothesis falsification by negation and much vaguer development of confidence in hypotheses consistent with some of their implications is an important practical challenge to confirming climate models. The presentation will discuss the ways in which predictions made by climate models for observable aspects of the present and past climate can be regarded as falsifiable hypotheses. The presentation will also include reasons why “passing” these tests does not provide complete confidence in predictions about the future by climate models. Finally, I will suggest that a “reductionist” view, in

  15. Teaching the fluctuation test in silico by using mutate: a program to distinguish between the adaptive and spontaneous mutation hypotheses.

    Science.gov (United States)

    Carvajal-Rodríguez, Antonio

    2012-07-01

    Mutate is a program developed for teaching purposes to impart a virtual laboratory class for undergraduate students of Genetics in Biology. The program emulates the so-called fluctuation test whose aim is to distinguish between spontaneous and adaptive mutation hypotheses in bacteria. The plan is to train students in certain key multidisciplinary aspects of current genetics such as sequence databases, DNA mutations, and hypothesis testing, while introducing the fluctuation test. This seminal experiment was originally performed studying Escherichia coli resistance to the infection by bacteriophage T1. The fluctuation test initiated the modern bacterial genetics that 25 years later ushered in the era of the recombinant DNA. Nowadays we know that some deletions in fhuA, the gene responsible for E. coli membrane receptor of T1, could cause the E. coli resistance to this phage. For the sake of simplicity, we will introduce the assumption that a single mutation generates the resistance to T1. During the practical, the students use the program to download some fhuA gene sequences, manually introduce some stop codon mutations, and design a fluctuation test to obtain data for distinguishing between preadaptative (spontaneous) and induced (adaptive) mutation hypotheses. The program can be launched from a browser or, if preferred, its executable file can be downloaded from http://webs.uvigo.es/acraaj/MutateWeb/Mutate.html. It requires the Java 5.0 (or higher) Runtime Environment (freely available at http://www.java.com). Copyright © 2012 Wiley Periodicals, Inc.

  16. An overview of currently available methods and future trends for physical activity

    Directory of Open Access Journals (Sweden)

    Alexander Kiško

    2013-12-01

    Full Text Available Background: Methodological limitations make comparison of various instruments difficult, although the number of publications on physical activity assessment has extensively increased. Therefore, systematization of techniques and definitions is essential for the improvement of knowledge in the area. Objective: This paper systematically describes and compares up-to-date methods that assess habitual physical activity and discusses main issues regarding the use and interpretation of data collected with these techniques. Methods: A general outline of the measures and techniques described above is presented in review form, along with their respective definition, usual applications, positive aspects and shortcomings. Results and conclusions: The various factors to be considered in the selection of physical activity assessment methods include goals, sample size, budget, cultural and social/environmental factors, physical burden for the subject, and statistical factors, such as accuracy and precision. It is concluded that no single current technique is able to quantify all aspects of physical activity under free-living conditions, requiring the use of complementary methods. In not too distant future, devices will take advantage of consumer technologies, such as mobile phones, GPS devices. It is important to perform other activities, such as detecting and responding to physical activity in a real time, creating new opportunities in measurement, remote compliance monitoring, data-driven discovery and intervention.

  17. Message and source factors, market uncertainty and extrafunctional information processing : hypotheses and empirical evidence

    NARCIS (Netherlands)

    Song, X.M.

    2001-01-01

    This article examines how the perceived quality of extrafunctional information improves the innovation management process and contributes to success with innovations. Data collected from 420 Japanese managers and 270 US managers are used to test hypotheses about the antecedents of satisfaction with

  18. Basally activated nonselective cation currents regulate the resting membrane potential in human and monkey colonic smooth muscle

    Science.gov (United States)

    Dwyer, Laura; Rhee, Poong-Lyul; Lowe, Vanessa; Zheng, Haifeng; Peri, Lauren; Ro, Seungil; Sanders, Kenton M.

    2011-01-01

    Resting membrane potential (RMP) plays an important role in determining the basal excitability of gastrointestinal smooth muscle. The RMP in colonic muscles is significantly less negative than the equilibrium potential of K+, suggesting that it is regulated not only by K+ conductances but by inward conductances such as Na+ and/or Ca2+. We investigated the contribution of nonselective cation channels (NSCC) to the RMP in human and monkey colonic smooth muscle cells (SMC) using voltage- and current-clamp techniques. Qualitative reverse transcriptase-polymerase chain reaction was performed to examine potential molecular candidates for these channels among the transient receptor potential (TRP) channel superfamily. Spontaneous transient inward currents and holding currents were recorded in human and monkey SMC. Replacement of extracellular Na+ with equimolar tetraethylammonium or Ca2+ with Mn2+ inhibited basally activated nonselective cation currents. Trivalent cations inhibited these channels. Under current clamp, replacement of extracellular Na+ with N-methyl-d-glucamine or addition of trivalent cations caused hyperpolarization. Three unitary conductances of NSCC were observed in human and monkey colonic SMC. Molecular candidates for basally active NSCC were TRPC1, C3, C4, C7, M2, M4, M6, M7, V1, and V2 in human and monkey SMC. Comparison of the biophysical properties of these TRP channels with basally active NSCC (bINSCC) suggests that TRPM4 and specific TRPC heteromultimer combinations may underlie the three single-channel conductances of bINSCC. In conclusion, these findings suggest that basally activated NSCC contribute to the RMP in human and monkey colonic SMC and therefore may play an important role in determining basal excitability of colonic smooth muscle. PMID:21566016

  19. Photonic Network R&D Activities in Japan-Current Activities and Future Perspectives

    Science.gov (United States)

    Kitayama, Ken-Ichi; Miki, Tetsuya; Morioka, Toshio; Tsushima, Hideaki; Koga, Masafumi; Mori, Kazuyuki; Araki, Soichiro; Sato, Ken-Ichi; Onaka, Hiroshi; Namiki, Shu; Aoyama, Tomonori

    2005-10-01

    R&D activities on photonic networks in Japan are presented. First, milestones in current ongoing R&D programs supported by Japanese government agencies are introduced, including long-distance and wavelength division multiplexing (WDM) fiber transmission, wavelength routing, optical burst switching (OBS), and control-plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP-over-WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R&D programs for photonic networks over the next 5 years until 2010, by focusing on the report that has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R&D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis, through the customer's initiative to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.

  20. Gender Relations and Economic Development: Hypotheses about the Reversal of Fortune in EurAsia

    NARCIS (Netherlands)

    de Pleijt, A.M.; van Zanden, J.L.; Carmichael, S.G.

    2016-01-01

    This paper develops an interrelated set of hypotheses about the links between gender relations, family systems and economic development in EurAsia. Firstly, we briefly discuss a number of ideas from the recent literature about the links between gender relations and economic development. Secondly, we

  1. Daydreaming Style Moderates the Relation between Working Memory and Mind Wandering: Integrating Two Hypotheses

    Science.gov (United States)

    Marcusson-Clavertz, David; Cardeña, Etzel; Terhune, Devin Blair

    2016-01-01

    Mind wandering--mentation unrelated to one's current activity and surroundings--is a ubiquitous phenomenon, but seemingly competing ideas have been proposed regarding its relation to executive cognitive processes. The control-failure hypothesis postulates that executive processes prevent mind wandering, whereas the global availability hypothesis…

  2. Hypothesizing Music Intervention Enhances Brain Functional Connectivity Involving Dopaminergic Recruitment: Common Neuro-correlates to Abusable Drugs.

    Science.gov (United States)

    Blum, Kenneth; Simpatico, Thomas; Febo, Marcelo; Rodriquez, Chris; Dushaj, Kristina; Li, Mona; Braverman, Eric R; Demetrovics, Zsolt; Oscar-Berman, Marlene; Badgaiyan, Rajendra D

    2017-07-01

    The goal of this review is to explore the clinical significance of music listening on neuroplasticity and dopaminergic activation by understanding the role of music therapy in addictive behavior treatment. fMRI data has shown that music listening intensely modifies mesolimbic structural changes responsible for reward processing (e.g., nucleus accumbens [NAc]) and may control the emotional stimuli's effect on autonomic and physiological responses (e.g., hypothalamus). Music listening has been proven to induce the endorphinergic response blocked by naloxone, a common opioid antagonist. NAc opioid transmission is linked to the ventral tegmental area (VTA) dopamine release. There are remarkable commonalities between listening to music and the effect of drugs on mesolimbic dopaminergic activation. It has been found that musical training before the age of 7 results in changes in white-matter connectivity, protecting carriers with low dopaminergic function (DRD2A1 allele, etc.) from poor decision-making, reward dependence, and impulsivity. In this article, we briefly review a few studies on the neurochemical effects of music and propose that these findings are relevant to the positive clinical findings observed in the literature. We hypothesize that music intervention enhances brain white matter plasticity through dopaminergic recruitment and that more research is needed to explore the efficacy of these therapies.

  3. Testing Alternative Hypotheses Regarding the Association between Behavioral Inhibition and Language Development in Toddlerhood

    Science.gov (United States)

    Watts, Ashley K. Smith; Patel, Deepika; Corley, Robin P.; Friedman, Naomi P.; Hewitt, John K.; Robinson, JoAnn L.; Rhee, Soo H.

    2014-01-01

    Studies have reported an inverse association between language development and behavioral inhibition or shyness across childhood, but the direction of this association remains unclear. This study tested alternative hypotheses regarding this association in a large sample of toddlers. Data on behavioral inhibition and expressive and receptive…

  4. Active and reactive power control of a current-source PWM-rectifier using space vectors

    Energy Technology Data Exchange (ETDEWEB)

    Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics

    1997-12-31

    In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.

  5. 75 FR 77939 - Agency Information Collection Activities; Revision of a Currently Approved Information Collection...

    Science.gov (United States)

    2010-12-14

    ...-0378] Agency Information Collection Activities; Revision of a Currently Approved Information Collection... Affairs, Office of Management and Budget. Comments should be addressed to the attention of the Desk... divided by 60 minutes per hour). Background: Under the Paperwork Reduction Act of 1995 (44 U.S.C. 3501...

  6. Testing Hypotheses on Risk Factors for Scientific Misconduct via Matched-Control Analysis of Papers Containing Problematic Image Duplications.

    Science.gov (United States)

    Fanelli, Daniele; Costas, Rodrigo; Fang, Ferric C; Casadevall, Arturo; Bik, Elisabeth M

    2018-02-19

    It is commonly hypothesized that scientists are more likely to engage in data falsification and fabrication when they are subject to pressures to publish, when they are not restrained by forms of social control, when they work in countries lacking policies to tackle scientific misconduct, and when they are male. Evidence to test these hypotheses, however, is inconclusive due to the difficulties of obtaining unbiased data. Here we report a pre-registered test of these four hypotheses, conducted on papers that were identified in a previous study as containing problematic image duplications through a systematic screening of the journal PLoS ONE. Image duplications were classified into three categories based on their complexity, with category 1 being most likely to reflect unintentional error and category 3 being most likely to reflect intentional fabrication. We tested multiple parameters connected to the hypotheses above with a matched-control paradigm, by collecting two controls for each paper containing duplications. Category 1 duplications were mostly not associated with any of the parameters tested, as was predicted based on the assumption that these duplications were mostly not due to misconduct. Categories 2 and 3, however, exhibited numerous statistically significant associations. Results of univariable and multivariable analyses support the hypotheses that academic culture, peer control, cash-based publication incentives and national misconduct policies might affect scientific integrity. No clear support was found for the "pressures to publish" hypothesis. Female authors were found to be equally likely to publish duplicated images compared to males. Country-level parameters generally exhibited stronger effects than individual-level parameters, because developing countries were significantly more likely to produce problematic image duplications. This suggests that promoting good research practices in all countries should be a priority for the international

  7. Landscape moderation of biodiversity patterns and processes - eight hypotheses.

    Science.gov (United States)

    Tscharntke, Teja; Tylianakis, Jason M; Rand, Tatyana A; Didham, Raphael K; Fahrig, Lenore; Batáry, Péter; Bengtsson, Janne; Clough, Yann; Crist, Thomas O; Dormann, Carsten F; Ewers, Robert M; Fründ, Jochen; Holt, Robert D; Holzschuh, Andrea; Klein, Alexandra M; Kleijn, David; Kremen, Claire; Landis, Doug A; Laurance, William; Lindenmayer, David; Scherber, Christoph; Sodhi, Navjot; Steffan-Dewenter, Ingolf; Thies, Carsten; van der Putten, Wim H; Westphal, Catrin

    2012-08-01

    Understanding how landscape characteristics affect biodiversity patterns and ecological processes at local and landscape scales is critical for mitigating effects of global environmental change. In this review, we use knowledge gained from human-modified landscapes to suggest eight hypotheses, which we hope will encourage more systematic research on the role of landscape composition and configuration in determining the structure of ecological communities, ecosystem functioning and services. We organize the eight hypotheses under four overarching themes. Section A: 'landscape moderation of biodiversity patterns' includes (1) the landscape species pool hypothesis-the size of the landscape-wide species pool moderates local (alpha) biodiversity, and (2) the dominance of beta diversity hypothesis-landscape-moderated dissimilarity of local communities determines landscape-wide biodiversity and overrides negative local effects of habitat fragmentation on biodiversity. Section B: 'landscape moderation of population dynamics' includes (3) the cross-habitat spillover hypothesis-landscape-moderated spillover of energy, resources and organisms across habitats, including between managed and natural ecosystems, influences landscape-wide community structure and associated processes and (4) the landscape-moderated concentration and dilution hypothesis-spatial and temporal changes in landscape composition can cause transient concentration or dilution of populations with functional consequences. Section C: 'landscape moderation of functional trait selection' includes (5) the landscape-moderated functional trait selection hypothesis-landscape moderation of species trait selection shapes the functional role and trajectory of community assembly, and (6) the landscape-moderated insurance hypothesis-landscape complexity provides spatial and temporal insurance, i.e. high resilience and stability of ecological processes in changing environments. Section D: 'landscape constraints on

  8. Method of Check of Statistical Hypotheses for Revealing of “Fraud” Point of Sale

    Directory of Open Access Journals (Sweden)

    T. M. Bolotskaya

    2011-06-01

    Full Text Available Application method checking of statistical hypotheses fraud Point of Sale working with purchasing cards and suspected of accomplishment of unauthorized operations is analyzed. On the basis of the received results the algorithm is developed, allowing receive an assessment of works of terminals in regime off-line.

  9. Voltage- and current-activated metal–insulator transition in VO2-based electrical switches: a lifetime operation analysis

    Directory of Open Access Journals (Sweden)

    Aurelian Crunteanu, Julien Givernaud, Jonathan Leroy, David Mardivirin, Corinne Champeaux, Jean-Christophe Orlianges, Alain Catherinot and Pierre Blondy

    2010-01-01

    Full Text Available Vanadium dioxide is an intensively studied material that undergoes a temperature-induced metal–insulator phase transition accompanied by a large change in electrical resistivity. Electrical switches based on this material show promising properties in terms of speed and broadband operation. The exploration of the failure behavior and reliability of such devices is very important in view of their integration in practical electronic circuits. We performed systematic lifetime investigations of two-terminal switches based on the electrical activation of the metal–insulator transition in VO2 thin films. The devices were integrated in coplanar microwave waveguides (CPWs in series configuration. We detected the evolution of a 10 GHz microwave signal transmitted through the CPW, modulated by the activation of the VO2 switches in both voltage- and current-controlled modes. We demonstrated enhanced lifetime operation of current-controlled VO2-based switching (more than 260 million cycles without failure compared with the voltage-activated mode (breakdown at around 16 million activation cycles. The evolution of the electrical self-oscillations of a VO2-based switch induced in the current-operated mode is a subtle indicator of the material properties modification and can be used to monitor its behavior under various external stresses in sensor applications.

  10. Myocardial perfusion imaging in Denmark: activity from 1997 to 2001 and current practice

    DEFF Research Database (Denmark)

    Petersen, Claus Leth; Kjaer, Andreas

    2003-01-01

    , and the survey thus covers all MPI performed in Denmark during the period in question. The number of MPI studies (examined patients) was 2,531 in 1997 (0.47 MPI/1,000/year) and 4,961 (0.93 MPI/1,000/year) in 2001, which is a doubling in activity in 5 years. Nineteen (95%) of the Danish departments performed MPI...... in 2001, and 14 (74%) of these reported that activity had increased over the past 5 years. MPI activity was unevenly distributed between hospitals and regions. In 2001, the university hospitals in the central Copenhagen region (capital) accounted for the highest MPI activity (2.00/1,000/year), while......A questionnaire was sent to all departments of nuclear medicine in Denmark (n=20) asking for details of myocardial perfusion imaging (MPI), including the number of patients examined each year from 1997 to 2001 and the current clinical and technical practice. All (100%) departments replied...

  11. Modulation by endothelin-1 of spontaneous activity and membrane currents of atrioventricular node myocytes from the rabbit heart.

    Directory of Open Access Journals (Sweden)

    Stéphanie C Choisy

    Full Text Available The atrioventricular node (AVN is a key component of the cardiac pacemaker-conduction system. Although it is known that receptors for the peptide hormone endothelin-1 (ET-1 are expressed in the AVN, there is very little information available on the modulatory effects of ET-1 on AVN electrophysiology. This study characterises for the first time acute modulatory effects of ET-1 on AVN cellular electrophysiology.Electrophysiological experiments were conducted in which recordings were made from rabbit isolated AVN cells at 35-37°C using the whole-cell patch clamp recording technique.Application of ET-1 (10 nM to spontaneously active AVN cells led rapidly (within ~13 s to membrane potential hyperpolarisation and cessation of spontaneous action potentials (APs. This effect was prevented by pre-application of the ET(A receptor inhibitor BQ-123 (1 µM and was not mimicked by the ET(B receptor agonist IRL-1620 (300 nM. In whole-cell voltage-clamp experiments, ET-1 partially inhibited L-type calcium current (I(Ca,L and rapid delayed rectifier K(+ current (I(Kr, whilst it transiently activated the hyperpolarisation-activated current (I(f at voltages negative to the pacemaking range, and activated an inwardly rectifying current that was inhibited by both tertiapin-Q (300 nM and Ba(2+ ions (2 mM; each of these effects was sensitive to ET(A receptor inhibition. In cells exposed to tertiapin-Q, ET-1 application did not produce membrane potential hyperpolarisation or immediate cessation of spontaneous activity; instead, there was a progressive decline in AP amplitude and depolarisation of maximum diastolic potential.Acutely applied ET-1 exerts a direct modulatory effect on AVN cell electrophysiology. The dominant effect of ET-1 in this study was activation of a tertiapin-Q sensitive inwardly rectifying K(+ current via ET(A receptors, which led rapidly to cell quiescence.

  12. AN INVESTIGATION OF THE HYPOTHESES FOR FORMATION OF THE PLATY-RIDGED-POLYGONIZED TERRAIN IN ELYSIUM PLANITIA, MARS

    Directory of Open Access Journals (Sweden)

    Z. Yue

    2017-07-01

    Full Text Available The origin of the platy-ridged-polygonized (PRP terrains on Martian surface has long been debated. The terrain has generally been classified as water, pack ice, or basalt lava related flow. The crater counting results of the PRP terrains suggest they are geologically very young; therefore, they are significant in understanding the recent evolution of Mars. This work evaluated the current hypotheses through detailed analysis of the distribution and microtopographies with the High Resolution Imaging Science Experiment (HiRISE images for the PRP terrains in Elysium Planitia, Mars. Quantitative measurements and statistics of the typical features of the PRP terrains were also made. In addition, we also found an analog site in Tarim Basin in Xinjiang, China. Our results suggest that mud flow is responsible for the formation of the PRP terrains on the Mars surface, although the hypothesis of low-viscosity basalt lava floods cannot be completely excluded. This finding implies that a regional environment suitable for liquid water may have existed in recent geologic time, which has great importance for future Mars scientific exploration.

  13. Principle and Control Design of Active Ground-Fault Arc Suppression Device for Full Compensation of Ground Current

    DEFF Research Database (Denmark)

    Wang, Wen; Zeng, Xiangjun; Yan, Lingjie

    2017-01-01

    current into the neutral without any large-capacity reactors, and thus avoids the aforementioned overvoltage. It compensates all the active, reactive and harmonic components of the ground current to reliably extinguish the ground-fault arcs. A dual-loop voltage control method is proposed to realize arc...... suppression without capacitive current detection. Its time-based feature also brings the benefit of fast response on ground-fault arc suppression. The principle of full current compensation is analyzed, together with the controller design method of the proposed device. Experiment on a prototype was carried...

  14. A Component-Minimized Single-Phase Active Power Decoupling Circuit with Reduced Current Stress to Semiconductor Switches

    DEFF Research Database (Denmark)

    Tang, Yi; Blaabjerg, Frede

    2015-01-01

    inductor. With such a configuration, this leg can control the current going into the two output capacitors connected in series for power decoupling, and the other leg can control the line current according to active and reactive power requirement. The proposed topology does not require additional passive...... component, e.g. inductors or film capacitors for ripple energy storage because this task can be accomplished by the dc-link capacitors, and therefore its implementation cost can be minimized. Another unique feature of the proposed topology is that the current stress of power semiconductors can be reduced...

  15. Hypotheses regarding the mechanisms of ayahuasca in the treatment of addictions.

    Science.gov (United States)

    Liester, Mitchell B; Prickett, James I

    2012-01-01

    Ayahuasca is a medicinal plant mixture utilized by indigenous peoples throughout the Amazon River basin for healing purposes. The "vine of the soul" or "vine of death," as it is known in South America, contains a combination of monoamine oxidase inhibitors and N,N-dimethyltryptamine (DMT). When ingested together, these medicines produce profound alterations in consciousness. Increasingly, ayahuasca is being utilized to treat addictions. However, the mechanism of action by which ayahuasca treats addictions remains unclear. We offer four hypotheses to explain possible biochemical, physiological, psychological, and transcendent mechanisms by which ayahuasca may exert its anti-addiction effects.

  16. Inhibition linearizes firing rate responses in human motor units: implications for the role of persistent inward currents.

    Science.gov (United States)

    Revill, Ann L; Fuglevand, Andrew J

    2017-01-01

    Motor neurons are the output neurons of the central nervous system and are responsible for controlling muscle contraction. When initially activated during voluntary contraction, firing rates of motor neurons increase steeply but then level out at modest rates. Activation of an intrinsic source of excitatory current at recruitment onset may underlie the initial steep increase in firing rate in motor neurons. We attempted to disable this intrinsic excitatory current by artificially activating an inhibitory reflex. When motor neuron activity was recorded while the inhibitory reflex was engaged, firing rates no longer increased steeply, suggesting that the intrinsic excitatory current was probably responsible for the initial sharp rise in motor neuron firing rate. During graded isometric contractions, motor unit (MU) firing rates increase steeply upon recruitment but then level off at modest rates even though muscle force continues to increase. The mechanisms underlying such firing behaviour are not known although activation of persistent inward currents (PICs) might be involved. PICs are intrinsic, voltage-dependent currents that activate strongly when motor neurons (MNs) are first recruited. Such activation might cause a sharp escalation in depolarizing current and underlie the steep initial rise in MU firing rate. Because PICs can be disabled with synaptic inhibition, we hypothesized that artificial activation of an inhibitory pathway might curb this initial steep rise in firing rate. To test this, human subjects performed slow triangular ramp contractions of the ankle dorsiflexors in the absence and presence of tonic synaptic inhibition delivered to tibialis anterior (TA) MNs by sural nerve stimulation. Firing rate profiles (expressed as a function of contraction force) of TA MUs recorded during these tasks were compared for control and stimulation conditions. Under control conditions, during the ascending phase of the triangular contractions, 93% of the firing

  17. Shallow Lunar Seismic Activity and the Current Stress State of the Moon

    Science.gov (United States)

    Watters, Thomas R.; Weber, Renee C.; Collins, Geoffrey C.; Johnson, Catherine L.

    2017-01-01

    A vast, global network of more than 3200 lobate thrust fault scarps has been revealed in high resolution Lunar Reconnaissance Orbiter Camera (LROC) images. The fault scarps are very young, less than 50 Ma, based on their small scale and crisp appearance, crosscutting relations with small-diameter impact craters, and rates of infilling of associated small, shallow graben and may be actively forming today. The population of young thrust fault scarps provides a window into the recent stress state of the Moon and offers insight into the origin of global lunar stresses. The distribution of orientations of the fault scarps is non-random, inconsistent with isotropic stresses from late-stage global contraction as the sole source of stress. Modeling shows that tidal stresses contribute significantly to the current stress state of the lunar crust. Tidal stresses (orbital recession and diurnal tides) superimposed on stresses from global contraction result in non-isotropic compressional stress and may produce thrust faults consistent with lobate scarp orientations. At any particular point on the lunar surface, peak compressive stress will be reached at a certain time in the diurnal cycle. Coseismic slip events on currently active thrust faults are expected to be triggered when peak stresses are reached. Analysis of the timing of the 28 the shallow moonquakes recorded by the Apollo seismic network shows that 19 indeed occur when the Moon is closer to apogee, while only 9 shallow events occur when the Moon is closer to perigee. Here we report efforts to refine the model for the current stress state of the Moon by investigating the contribution of polar wander. Progress on relocating the epicentral locations of the shallow moonquakes using an algorithm designed for sparse networks is also reported.

  18. Code Development and Validation Towards Modeling and Diagnosing Current Redistribution in an ITER-Type Superconducting Cable Subject to Current Imbalance

    International Nuclear Information System (INIS)

    Zani, L.; Gille, P.E.; Gonzales, C.; Kuppel, S.; Torre, A.

    2009-01-01

    In the framework of ITER magnet R and D activities, a significant number of conductor short-samples or inserts were tested throughout the past decades, either for development on cable layouts or for industrial qualifications. On a certain number of them critical properties degradations were encountered, some of which were identified to be caused by current imbalance between the different strands bundles twisted inside the cable. In order to address the analyses of those samples as reliably as possible, CEA developed a dedicated home code named Coupled Algorithm Resistive Modelling Electrical Network (CARMEN) having basically two specific functionalities: -a first routine which is devoted to compute strand bundles trajectories, with bundles down to the individual strand scale. This point allows to obtain a realistic E(J) law over the full conductor length -a second routine which is devoted to model inter-bundle currents redistribution, taking into account the magnetic field map. It basically makes use of a relevant discrete electrical network with defined sections including E(J) law obtained from the above-mentioned subroutine As a result, the E-J or E-T curves can be calculated and compared to the experimental data, provided adapted inputs on sample features are considered, such as strand contact resistances in joints, inter-bundles resistances or cable geometry. In a first part, the paper describes the different hypotheses that built the code structure, and in a second part, the application to the ITER TFCl insert coil is presented, focusing particularly on the validation of the potential use of the code to stand as a diagnostic tool for currents imbalance probing

  19. Cell-Type Specific Development of the Hyperpolarization-Activated Current, Ih, in Prefrontal Cortical Neurons

    Directory of Open Access Journals (Sweden)

    Sha-Sha Yang

    2018-05-01

    Full Text Available H-current, also known as hyperpolarization-activated current (Ih, is an inward current generated by the hyperpolarization-activated cyclic nucleotide-gated (HCN cation channels. Ih plays an essential role in regulating neuronal properties, synaptic integration and plasticity, and synchronous activity in the brain. As these biological factors change across development, the brain undergoes varying levels of vulnerability to disorders like schizophrenia that disrupt prefrontal cortex (PFC-dependent function. However, developmental changes in Ih in PFC neurons remains untested. Here, we examine Ih in pyramidal neurons vs. gamma-aminobutyric acid (GABAergic parvalbumin-expressing (PV+ interneurons in developing mouse PFC. Our findings show that the amplitudes of Ih in these cell types are identical during the juvenile period but differ at later time points. In pyramidal neurons, Ih amplitude significantly increases from juvenile to adolescence and follows a similar trend into adulthood. In contrast, the amplitude of Ih in PV+ interneurons decreases from juvenile to adolescence, and does not change from adolescence to adulthood. Moreover, the kinetics of HCN channels in pyramidal neurons is significantly slower than in PV+ interneurons, with a gradual decrease in pyramidal neurons and a gradual increase in PV+ cells across development. Our study reveals distinct developmental trajectories of Ih in pyramidal neurons and PV+ interneurons. The cell-type specific alteration of Ih during the critical period from juvenile to adolescence reflects the contribution of Ih to the maturation of the PFC and PFC-dependent function. These findings are essential for a better understanding of normal PFC function, and for elucidating Ih’s crucial role in the pathophysiology of neurodevelopmental disorders.

  20. Current activities handbook: formerly utilized sites remedial action program

    International Nuclear Information System (INIS)

    1981-01-01

    This volume is one of a series produced under contract with the DOE, by Politech Corporation to develop a legislative and regulatory data base to assist the FUSRAP management in addressing the institutional and socioeconomic issues involved in carrying out the Formerly Utilized Sites Remedial Action Program. This Information Handbook series contains information about all relevant government agencies at the Federal and state levels, the pertinent programs they administer, each affected state legislature, and current Federal and state legislative and regulatory initiatives. This volume is a compilation of information about the activities each of the thirteen state legislatures potentially affected by the Formerly Utilized Sites Remedial Action Program. It contains a description of the state legislative procedural rules and a schedule of each legislative session; a summary of pending relevant legislation; the name and telephone number of legislative and state agency contacts; and the full text of all bills identified

  1. Current activities handbook: formerly utilized sites remedial action program

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-02-27

    This volume is one of a series produced under contract with the DOE, by Politech Corporation to develop a legislative and regulatory data base to assist the FUSRAP management in addressing the institutional and socioeconomic issues involved in carrying out the Formerly Utilized Sites Remedial Action Program. This Information Handbook series contains information about all relevant government agencies at the Federal and state levels, the pertinent programs they administer, each affected state legislature, and current Federal and state legislative and regulatory initiatives. This volume is a compilation of information about the activities each of the thirteen state legislatures potentially affected by the Formerly Utilized Sites Remedial Action Program. It contains a description of the state legislative procedural rules and a schedule of each legislative session; a summary of pending relevant legislation; the name and telephone number of legislative and state agency contacts; and the full text of all bills identified.

  2. A criterion for testing hypotheses about the covariance function of a stationary Gaussian stochastic process

    OpenAIRE

    Kozachenko, Yuriy; Troshki, Viktor

    2015-01-01

    We consider a measurable stationary Gaussian stochastic process. A criterion for testing hypotheses about the covariance function of such a process using estimates for its norm in the space $L_p(\\mathbb {T}),\\,p\\geq1$, is constructed.

  3. Voltage sensitivity of M2 muscarinic receptors underlies the delayed rectifier-like activation of ACh-gated K(+) current by choline in feline atrial myocytes.

    Science.gov (United States)

    Navarro-Polanco, Ricardo A; Aréchiga-Figueroa, Iván A; Salazar-Fajardo, Pedro D; Benavides-Haro, Dora E; Rodríguez-Elías, Julio C; Sachse, Frank B; Tristani-Firouzi, Martin; Sánchez-Chapula, José A; Moreno-Galindo, Eloy G

    2013-09-01

    Choline (Ch) is a precursor and metabolite of the neurotransmitter acetylcholine (ACh). In canine and guinea pig atrial myocytes, Ch was shown to activate an outward K(+) current in a delayed rectifier fashion. This current has been suggested to modulate cardiac electrical activity and to play a role in atrial fibrillation pathophysiology. However, the exact nature and identity of this current has not been convincingly established. We recently described the unique ligand- and voltage-dependent properties of muscarinic activation of ACh-activated K(+) current (IKACh) and showed that, in contrast to ACh, pilocarpine induces a current with delayed rectifier-like properties with membrane depolarization. Here, we tested the hypothesis that Ch activates IKACh in feline atrial myocytes in a voltage-dependent manner similar to pilocarpine. Single-channel recordings, biophysical profiles, specific pharmacological inhibition and computational data indicate that the current activated by Ch is IKACh. Moreover, we show that membrane depolarization increases the potency and efficacy of IKACh activation by Ch and thus gives the appearance of a delayed rectifier activating K(+) current at depolarized potentials. Our findings support the emerging concept that IKACh modulation is both voltage- and ligand-specific and reinforce the importance of these properties in understanding cardiac physiology.

  4. Learned Helplessness and Depression in a Clinical Population: A Test of Two Behavioral Hypotheses

    Science.gov (United States)

    And Others; Price, Kenneth P.

    1978-01-01

    This study was undertaken to extend the learned helplessness phenomenon to a clinical population and to test the competing hypotheses of Seligman and Lewinsohn. 96 male hospitalized psychiatric and medical patients were randomly assigned to one of four experimental conditions. Results replicate the learned helplessness phenomenon in a group of…

  5. Is There an Opportunity for Current Chemotherapeutics to Up-regulate MIC-A/B Ligands?

    Directory of Open Access Journals (Sweden)

    Kendel Quirk

    2017-10-01

    Full Text Available Natural killer (NK cells are critical effectors of the immune system. NK cells recognize unhealthy cells by specific ligands [e.g., MHC- class I chain related protein A or B (MIC-A/B] for further elimination by cytotoxicity. Paradoxically, cancer cells down-regulate MIC-A/B and evade NK cell’s anticancer activity. Recent data indicate that cellular-stress induces MIC-A/B, leading to enhanced sensitivity of cancer cells to NK cell-mediated cytotoxicity. In this Perspective article, we hypothesize that current chemotherapeutics at sub-lethal, non-toxic dose may promote cellular-stress and up-regulate the expression of MIC-A/B ligands to augment cancer’s sensitivity to NK cell-mediated cytotoxicity. Preliminary data from two human breast cancer cell lines, MDA-MB-231 and T47D treated with clinically relevant therapeutics such as doxorubicin, paclitaxel and methotrexate support the hypothesis. The goal of this Perspective is to underscore the prospects of current chemotherapeutics in NK cell immunotherapy, and discuss potential challenges and opportunities to improve cancer therapy.

  6. Skin Stem Cell Hypotheses and Long Term Clone Survival – Explored Using Agent-based Modelling

    Science.gov (United States)

    Li, X.; Upadhyay, A. K.; Bullock, A. J.; Dicolandrea, T.; Xu, J.; Binder, R. L.; Robinson, M. K.; Finlay, D. R.; Mills, K. J.; Bascom, C. C.; Kelling, C. K.; Isfort, R. J.; Haycock, J. W.; MacNeil, S.; Smallwood, R. H.

    2013-01-01

    Epithelial renewal in skin is achieved by the constant turnover and differentiation of keratinocytes. Three popular hypotheses have been proposed to explain basal keratinocyte regeneration and epidermal homeostasis: 1) asymmetric division (stem-transit amplifying cell); 2) populational asymmetry (progenitor cell with stochastic fate); and 3) populational asymmetry with stem cells. In this study, we investigated lineage dynamics using these hypotheses with a 3D agent-based model of the epidermis. The model simulated the growth and maintenance of the epidermis over three years. The offspring of each proliferative cell was traced. While all lineages were preserved in asymmetric division, the vast majority were lost when assuming populational asymmetry. The third hypothesis provided the most reliable mechanism for self-renewal by preserving genetic heterogeneity in quiescent stem cells, and also inherent mechanisms for skin ageing and the accumulation of genetic mutation. PMID:23712735

  7. Educational attainment but not measures of current socioeconomic circumstances are associated with leukocyte telomere length in healthy older men and women.

    Science.gov (United States)

    Steptoe, Andrew; Hamer, Mark; Butcher, Lee; Lin, Jue; Brydon, Lena; Kivimäki, Mika; Marmot, Michael; Blackburn, Elizabeth; Erusalimsky, Jorge D

    2011-10-01

    Low socioeconomic status (SES) may be associated with accelerated biological aging, but findings relating SES with telomere length have been inconsistent. We tested the hypotheses that shorter telomere length and telomerase activity would be related more robustly to education, an early life indicator of socioeconomic position, than to current indicators of socioeconomic circumstances. Healthy men and women aged 53-76 years from the Whitehall II epidemiological cohort provided blood samples from which telomere length was assessed in 448 and telomerase activity in 416. Educational attainment was classified into four levels, while household income and grade of employment were measured as indicators of current socioeconomic circumstances. Age, gender, blood pressure, glycated hemoglobin, high density lipoprotein cholesterol, smoking, body mass index and physical activity were included as covariates. We found that lower educational attainment was associated with shorter telomere length after controlling statistically for biological and behavioral covariates. Neither household income nor employment grade was related to telomere length. The association between telomere length and education remained significant after adjusting for current socioeconomic circumstances. In men, highest levels of telomerase activity were found in the lowest education group. We conclude that low SES defined in terms of education but not current socioeconomic circumstances is associated with shortened telomeres. Low educational attainment may be an indicator of long-term SES trajectories, and be associated with accumulated allostatic load resulting in telomere shortening. Education may also promote problem-solving skills leading to reduced biological stress responsivity, with favorable consequences for biological aging. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Abnormal sympathetic nerve activity in women exposed to cigarette smoke: a potential mechanism to explain increased cardiac risk.

    Science.gov (United States)

    Middlekauff, Holly R; Park, Jeanie; Agrawal, Harsh; Gornbein, Jeffrey A

    2013-11-15

    In women, cardiac deaths attributable to tobacco exposure have reached the same high levels as men. Normally, sympathetic nerve activity (SNA) fluctuates according to the menstrual phase, but in habitual smokers, SNA levels remain constant. Our purpose is to extend these observations to other groups of women exposed to tobacco smoke and to explore potential mechanisms. We hypothesize that women exposed to secondhand smoke, but not former smokers, have nonfluctuating SNA compared with never smokers, and that impaired baroreflex suppression of SNA, and/or heightened central SNA responses, underlie this nonfluctuating SNA. We also hypothesize that female smokers have impaired nocturnal blood pressure dipping, normally mediated by modulation of SNA. In 49 females (19 never, 12 current, 9 former, 9 passive smokers), SNA was recorded (microneurography) during high- and low-hormone ovarian phases at rest, during pharmacological baroreflex testing, and during the cold pressor test (CPT). Twenty-four hour blood pressure (BP) monitoring was performed. Current and passive smokers, but not former smokers, had a nonfluctuating pattern of SNA, unlike never smokers in whom SNA varied with the menstrual phase. Baroreflex control of SNA was significantly blunted in current smokers, independent of menstrual phase. In passive smokers, SNA response to CPT was markedly increased. Nondipping was unexpectedly high in all groups. SNA does not vary during the menstrual cycle in active and passive smokers, unlike never and former smokers. Baroreflex control of SNA is blunted in current smokers, whereas SNA response to CPT is heightened in passive smokers. Smoking cessation is associated with return of the altered SNA pattern to normal.

  9. Thermal activation of current in an inhomogeneous Schottky diode with a Gaussian distribution of barrier height

    International Nuclear Information System (INIS)

    Guo-Ping, Ru; Rong, Yu; Yu-Long, Jiang; Gang, Ruan

    2010-01-01

    This paper investigates the thermal activation behaviour of current in an inhomogeneous Schottky diode with a Gaussian distribution of barrier height by numerical simulation. The analytical Gaussian distribution model predicted that the I-V-T curves may intersect with the possibility of the negative thermal activation of current, but may be contradictory to the thermionic emission mechanism in a Schottky diode. It shows that the cause of the unphysical phenomenon is related to the incorrect calculation of current across very low barriers. It proposes that junction voltage V j , excluding the voltage drop across series resistance from the external bias, is a crucial parameter for correct calculation of the current across very low barriers. For correctly employing the thermionic emission model, V j needs to be smaller than the barrier height ø. With proper scheme of series resistance connection where the condition of V j > ø is guaranteed, I-V-T curves of an inhomogeneous Schottky diode with a Gaussian distribution of barrier height have been simulated, which demonstrate normal thermal activation. Although the calculated results exclude the intersecting possibility of I-V-T curves with an assumption of temperature-independent series resistance, it shows that the intersecting is possible when the series resistance has a positive temperature coefficient. Finally, the comparison of our numerical and analytical results indicates that the analytical Gaussian distribution model is valid and accurate in analysing I-V-T curves only for small barrier height inhomogeneity. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  10. Testing contingency hypotheses in budgetary research: An evaluation of the use of moderated regression analysis

    NARCIS (Netherlands)

    Hartmann, Frank G.H.; Moers, Frank

    1999-01-01

    In the contingency literature on the behavioral and organizational effects of budgeting, use of the Moderated Regression Analysis (MRA) technique is prevalent. This technique is used to test contingency hypotheses that predict interaction effects between budgetary and contextual variables. This

  11. Role of Active Versus Passive Complementary and Integrative Health Approaches in Pain Management.

    Science.gov (United States)

    Cosio, David; Lin, Erica

    2018-01-01

    A general conclusion about the treatment of chronic, noncancer pain is that the results from traditional, passive modalities are disheartening. Perhaps this may be due to the propensity of patients to seek out passive versus active treatments. In pain management, active treatments should be the primary focus, with passive interventions as an adjunct. The current study tested the hypotheses that Veterans would report a greater significant increase in active versus transitional and active versus passive complementary and integrative health (CIH) utilization after completing a formal pain education program. The current study is a secondary analysis of existing data from an original study. The current study used a quasi-experimental, 1-group, pre-/posttest design. One hundred three Veterans completed a 12-week, "Pain Education School" program at a Midwestern VA Medical Center between November 4, 2011, and October 26, 2012. As part of the introduction and conclusion of the program, all Veterans completed a pre- and posteducation assessment which included an adaptation of the Complementary and Alternative Medicine Questionnaire©, SECTION A: Use of Alternative Health Care Providers measure. Significant differences were found between the pre- and posttest measures of use of active ( P  = .000) ( p pain education program also seems to be aligned with the goal of pain self-management, which is to utilize more active interventions as a primary therapy.

  12. Association between physical activity and major depressive disorder among current or former smokers with pulmonary disease.

    Science.gov (United States)

    Loprinzi, Paul D; Kane, Christy; Walker, Jerome F

    2013-11-01

    To examine the association between physical activity and major depressive disorder (MDD) in a nationally representative sample of current or former smokers with pulmonary impairments. The analyzed sample from the National Health and Nutrition Examination Survey (NHANES) 2007-2010 included 536 adults who indicated that they were current or former smokers, had at least mild pulmonary impairment (FEV1/FVCdepression and physical activity data. After controlling for asthma status, pulmonary impairment, age, poverty-to-income ratio (PIR), education, gender, marital status, body mass index (BMI), cotinine, comorbidity index, race-ethnicity, and smoking status, those who met physical activity guidelines had a 59% (odds ratio (OR)=0.41; 95% confidence interval (CI): 0.18-0.94) lower odds of having MDD. Using multivariate linear regression with depression symptoms as the outcome variable, and after adjustments, physical activity was inversely associated with depression symptoms in a dose-response manner; lowest tertile was the referent group, middle tertile coefficient: -1.06 (95% CI: -1.98 to -0.14), and highest tertile coefficient: -1.10 (95% CI: -1.84 to -0.34). Physical activity inversely associates with MDD in adults with pulmonary impairments, and does so in a dose-response manner. This suggests that individuals with pulmonary impairments should be encouraged to engage in enjoyable, safe forms of physical activity in a progressive manner. © 2013.

  13. Interactions between domestic and export markets for softwood lumber and plywood: tests of six hypotheses.

    Science.gov (United States)

    David R. Darr

    1981-01-01

    Price formation in export markets and available data on export and domestic markets are discussed. The results of tests of several hypotheses about interactions between domestic and export markets are presented and interpreted from the standpoints of trade promotion and trade policy.

  14. Utility of Krashen's Five Hypotheses in the Saudi Context of Foreign Language Acquisition/Learning

    Science.gov (United States)

    Gulzar, Malik Ajmal; Gulnaz, Fahmeeda; Ijaz, Attiya

    2014-01-01

    In the last twenty years, the paradigm that has dominated the discipline of language teaching is the SLA theory and Krashen's five hypotheses which are still proving flexible to accommodate earlier reforms. This paper reviews second language acquisition (SLA) theory to establish an understanding of its role in the EFL/ESL classrooms. Other areas…

  15. Agnostic Active Learning Without Constraints

    OpenAIRE

    Beygelzimer, Alina; Hsu, Daniel; Langford, John; Zhang, Tong

    2010-01-01

    We present and analyze an agnostic active learning algorithm that works without keeping a version space. This is unlike all previous approaches where a restricted set of candidate hypotheses is maintained throughout learning, and only hypotheses from this set are ever returned. By avoiding this version space approach, our algorithm sheds the computational burden and brittleness associated with maintaining version spaces, yet still allows for substantial improvements over supervised learning f...

  16. Past challenges faced: An overview of current educational activities of IUTOX

    International Nuclear Information System (INIS)

    Dybing, Erik; MacGregor, Judith; Malmfors, Torbjoern; Chipman, J. Kevin; Wright, Paul

    2005-01-01

    Over the past decade, educational programmes have been the main focus of the activities of the International Union of Toxicology (IUTOX). The IUTOX educational programmes are dynamic and have been growing in scope and frequency each year. It is envisaged that this growth will continue with guidance from our member societies and the continuing support of our sponsors. Presently, IUTOX is engaged in the following educational programmes: (1) International congresses that provide the opportunity for direct communication of current toxicological information. Fellowships are sponsored to facilitate attendance at these congresses for toxicologists in need. (2) Workshops that permit interaction on a more localised level of topics of more regional interest. Workshops have served to help stimulate formation of toxicology societies by bringing together sufficient scientists to facilitate these discussions. (3) Continuing educational (CE) programmes at member society meetings. Topics are prioritised based on input received from the local societies. Programmes often are those from CE courses given at meetings, such as conferences of the US Society of Toxicology (US SOT) and EUROTOX from the previous year. (4) Biennial Risk Assessment Summer School (RASS), an intensive week-long interaction between senior toxicologists who serve as faculty with attendees providing individual training. (5) Dissemination of donated printed toxicological books from publishers and syllabi from continuing education courses to regional locations. (6) Web-based interactive training programmes in regions where formal toxicological educational programmes are limited or lacking. (7) Preparation and distribution of monographs on selected topics of very current interest. Monographs on environmental oestrogens and genetically-modified foods have been published. The recent activities in each of these programmes are reviewed in this paper

  17. Nitric oxide/cGMP/PKG signaling pathway activated by M1-type muscarinic acetylcholine receptor cascade inhibits Na+-activated K+ currents in Kenyon cells

    Science.gov (United States)

    Hasebe, Masaharu

    2016-01-01

    The interneurons of the mushroom body, known as Kenyon cells, are essential for the long-term memory of olfactory associative learning in some insects. Some studies have reported that nitric oxide (NO) is strongly related to this long-term memory in Kenyon cells. However, the target molecules and upstream and downstream NO signaling cascades are not completely understood. Here we analyzed the effect of the NO signaling cascade on Na+-activated K+ (KNa) channel activity in Kenyon cells of crickets (Gryllus bimaculatus). We found that two different NO donors, S-nitrosoglutathione (GSNO) and S-nitroso-N-acetyl-dl-penicillamine (SNAP), strongly suppressed KNa channel currents. Additionally, this inhibitory effect of GSNO on KNa channel activity was diminished by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase (sGC), and KT5823, an inhibitor of protein kinase G (PKG). Next, we analyzed the role of ACh in the NO signaling cascade. ACh strongly suppressed KNa channel currents, similar to NO donors. Furthermore, this inhibitory effect of ACh was blocked by pirenzepine, an M1 muscarinic ACh receptor antagonist, but not by 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide (4-DAMP) and mecamylamine, an M3 muscarinic ACh receptor antagonist and a nicotinic ACh receptor antagonist, respectively. The ACh-induced inhibition of KNa channel currents was also diminished by the PLC inhibitor U73122 and the calmodulin antagonist W-7. Finally, we found that ACh inhibition was blocked by the nitric oxide synthase (NOS) inhibitor NG-nitro-l-arginine methyl ester (l-NAME). These results suggested that the ACh signaling cascade promotes NO production by activating NOS and NO inhibits KNa channel currents via the sGC/cGMP/PKG signaling cascade in Kenyon cells. PMID:26984419

  18. EVOLUTION OF CURRENTS OF OPPOSITE SIGNS IN THE FLARE-PRODUCTIVE SOLAR ACTIVE REGION NOAA 10930

    International Nuclear Information System (INIS)

    Ravindra, B.; Venkatakrishnan, P.; Tiwari, Sanjiv Kumar; Bhattacharyya, R.

    2011-01-01

    Analysis of a time series of high spatial resolution vector magnetograms of the active region NOAA 10930 available from the Solar Optical Telescope SpectroPolarimeter on board Hinode revealed that there is a mixture of upward and downward currents in the two footpoints of an emerging flux rope. The flux emergence rate is almost the same in both the polarities. We observe that along with an increase in magnetic flux, the net current in each polarity increases initially for about three days after which it decreases. This net current is characterized by having exactly opposite signs in each polarity while its magnitude remains almost the same most of the time. The decrease of the net current in both the polarities is due to the increase of current having a sign opposite to that of the net current. The dominant current, with the same sign as the net current, is seen to increase first and then decreases during the major X-class flares. Evolution of non-dominant current appears to be a necessary condition for flare initiation. The above observations can be plausibly explained in terms of the superposition of two different force-free states resulting in a non-zero Lorentz force in the corona. This Lorentz force then pushes the coronal plasma and might facilitate the magnetic reconnection required for flares. Also, the evolution of the net current is found to follow the evolution of magnetic shear at the polarity inversion line.

  19. Cross-cultural adaptation and validation of the Behcet's Disease Current Activity Form in Korea.

    Science.gov (United States)

    Choi, Hyo Jin; Seo, Mi Ryoung; Ryu, Hee Jung; Baek, Han Joo

    2015-09-01

    This study was undertaken to perform a cross-cultural adaptation of the Behcet's Disease Current Activity Form (BDCAF, version 2006) questionnaire to the Korean language and to evaluate its reliability and validity in a population of Korean patients with Behcet's disease (BD). A cross-cultural study was conducted among patients with BD who attended our rheumatology clinic between November 2012 and March 2013. There were 11 males and 35 females in the group. The mean age of the participants was 48.5 years and the mean disease duration was 6.4 years. The first BDCAF questionnaire was completed on arrival and the second assessment was performed 20 minutes later by a different physician. The test-retest reliability was analyzed by computing κ statistics. Kappa scores of > 0.6 indicated a good agreement. To assess the validity, we compared the total BDCAF score with the patient's/clinician's perception of disease activity and the Korean version of the Behcet's Disease Quality of Life (BDQOL). For the test-retest reliability, good agreements were achieved on items such as headache, oral/genital ulceration, erythema, skin pustules, arthralgia, nausea/vomiting/abdominal pain, and diarrhea with altered/frank blood per rectum. Moderate agreement was observed for eye and nervous system involvement. We achieved a fair agreement for arthritis and major vessel involvement. Significant correlations were obtained between the total BDCAF score with the BDQOL and the patient's/clinician's perception of disease activity p < 0.05). The Korean version of the BDCAF is a reliable and valid instrument for measuring current disease activity in Korean BD patients.

  20. Low Voltage Current Mode Switched-Current-Mirror Mixer

    Directory of Open Access Journals (Sweden)

    Chunhua Wang

    2009-09-01

    Full Text Available A new CMOS active mixer topology can operate at 1 V supply voltage by use of SCM (switched currentmirror. Such current-mode mixer requires less voltage headroom with good linearization. Mixing is achieved with four improved current mirrors, which are alternatively activated. For ideal switching, the operation is equivalent to a conventional active mixer. This paper analyzes the performance of the SCM mixer, in comparison with the conventional mixer, demonstrating competitive performance at a lower supply voltage. Moreover, the new mixer’s die, without any passive components, is very small, and the conversion gain is easy to adjust. An experimental prototype was designed and simulated in standard chartered 0.18μm RF CMOS Process with Spectre in Cadence Design Systems. Experimental results show satisfactory mixer performance at 2.4 GHz.

  1. A brief report on the statistical study of net electric current in solar active regions with longitudinal fields of opposite polarity

    International Nuclear Information System (INIS)

    Gao Yu

    2013-01-01

    Dynamic processes occurring in solar active regions are dominated by the solar magnetic field. As of now, observations using a solar magnetograph have supplied us with the vector components of a solar photospheric magnetic field. The two transverse components of a photospheric magnetic field allow us to compute the amount of electric current. We found that the electric current in areas with positive (negative) polarity due to the longitudinal magnetic field have both positive and negative signs in an active region, however, the net current is found to be an order-of-magnitude less than the mean absolute magnitude and has a preferred sign. In particular, we have statistically found that there is a systematic net electric current from areas with negative (positive) polarity to areas with positive (negative) polarity in solar active regions in the northern (southern) hemisphere, but during the solar minimum this tendency is reversed over time at some latitudes. The result indicates that there is weak net electric current in areas of solar active regions with opposite polarity, thus providing further details about the hemispheric helicity rule found in a series of previous studies.

  2. Current Reactor Physics Benchmark Activities at the Idaho National Laboratory

    International Nuclear Information System (INIS)

    Bess, John D.; Marshall, Margaret A.; Gorham, Mackenzie L.; Christensen, Joseph; Turnbull, James C.; Clark, Kim

    2011-01-01

    The International Reactor Physics Experiment Evaluation Project (IRPhEP) (1) and the International Criticality Safety Benchmark Evaluation Project (ICSBEP) (2) were established to preserve integral reactor physics and criticality experiment data for present and future research. These valuable assets provide the basis for recording, developing, and validating our integral nuclear data, and experimental and computational methods. These projects are managed through the Idaho National Laboratory (INL) and the Organisation for Economic Co-operation and Development Nuclear Energy Agency (OECD-NEA). Staff and students at the Department of Energy - Idaho (DOE-ID) and INL are engaged in the development of benchmarks to support ongoing research activities. These benchmarks include reactors or assemblies that support Next Generation Nuclear Plant (NGNP) research, space nuclear Fission Surface Power System (FSPS) design validation, and currently operational facilities in Southeastern Idaho.

  3. Perceiving active listening activates the reward system and improves the impression of relevant experiences.

    Science.gov (United States)

    Kawamichi, Hiroaki; Yoshihara, Kazufumi; Sasaki, Akihiro T; Sugawara, Sho K; Tanabe, Hiroki C; Shinohara, Ryoji; Sugisawa, Yuka; Tokutake, Kentaro; Mochizuki, Yukiko; Anme, Tokie; Sadato, Norihiro

    2015-01-01

    Although active listening is an influential behavior, which can affect the social responses of others, the neural correlates underlying its perception have remained unclear. Sensing active listening in social interactions is accompanied by an improvement in the recollected impressions of relevant experiences and is thought to arouse positive feelings. We therefore hypothesized that the recognition of active listening activates the reward system, and that the emotional appraisal of experiences that had been subject to active listening would be improved. To test these hypotheses, we conducted functional magnetic resonance imaging (fMRI) on participants viewing assessments of their own personal experiences made by evaluators with or without active listening attitude. Subjects rated evaluators who showed active listening more positively. Furthermore, they rated episodes more positively when they were evaluated by individuals showing active listening. Neural activation in the ventral striatum was enhanced by perceiving active listening, suggesting that this was processed as rewarding. It also activated the right anterior insula, representing positive emotional reappraisal processes. Furthermore, the mentalizing network was activated when participants were being evaluated, irrespective of active listening behavior. Therefore, perceiving active listening appeared to result in positive emotional appraisal and to invoke mental state attribution to the active listener.

  4. Active damping of LLCL-filter resonance based on LC-trap voltage and capacitor current feedback

    DEFF Research Database (Denmark)

    Huang, Min; Wang, Xiongfei; Loh, Poh Chiang

    2015-01-01

    . In this paper, different feedback coefficients like the proportional, derivative, integral, high pass and low pass feedback coefficients of the filter capacitor current and the LC-trap circuit voltage are investigated for damping the filter resonance. Active damping methods are analyzed by using the concept...

  5. Phylemon 2.0: a suite of web-tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing.

    Science.gov (United States)

    Sánchez, Rubén; Serra, François; Tárraga, Joaquín; Medina, Ignacio; Carbonell, José; Pulido, Luis; de María, Alejandro; Capella-Gutíerrez, Salvador; Huerta-Cepas, Jaime; Gabaldón, Toni; Dopazo, Joaquín; Dopazo, Hernán

    2011-07-01

    Phylemon 2.0 is a new release of the suite of web tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing. It has been designed as a response to the increasing demand of molecular sequence analyses for experts and non-expert users. Phylemon 2.0 has several unique features that differentiates it from other similar web resources: (i) it offers an integrated environment that enables evolutionary analyses, format conversion, file storage and edition of results; (ii) it suggests further analyses, thereby guiding the users through the web server; and (iii) it allows users to design and save phylogenetic pipelines to be used over multiple genes (phylogenomics). Altogether, Phylemon 2.0 integrates a suite of 30 tools covering sequence alignment reconstruction and trimming; tree reconstruction, visualization and manipulation; and evolutionary hypotheses testing.

  6. Phylemon 2.0: a suite of web-tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing

    Science.gov (United States)

    Sánchez, Rubén; Serra, François; Tárraga, Joaquín; Medina, Ignacio; Carbonell, José; Pulido, Luis; de María, Alejandro; Capella-Gutíerrez, Salvador; Huerta-Cepas, Jaime; Gabaldón, Toni; Dopazo, Joaquín; Dopazo, Hernán

    2011-01-01

    Phylemon 2.0 is a new release of the suite of web tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing. It has been designed as a response to the increasing demand of molecular sequence analyses for experts and non-expert users. Phylemon 2.0 has several unique features that differentiates it from other similar web resources: (i) it offers an integrated environment that enables evolutionary analyses, format conversion, file storage and edition of results; (ii) it suggests further analyses, thereby guiding the users through the web server; and (iii) it allows users to design and save phylogenetic pipelines to be used over multiple genes (phylogenomics). Altogether, Phylemon 2.0 integrates a suite of 30 tools covering sequence alignment reconstruction and trimming; tree reconstruction, visualization and manipulation; and evolutionary hypotheses testing. PMID:21646336

  7. Five hypotheses concerning the fate of the Singapore issues in the Doha Round

    OpenAIRE

    Evenett, Simon J.

    2017-01-01

    At the Cancún Ministerial Conference, the members of the World Trade Organization (WTO) disagreed on whether to launch negotiations on multilateral disciplines concerning the four areas of government policy collectively known as the ‘Singapore issues'. This amounted to a decision not to expand the WTO's boundaries along these dimensions. In this paper, five hypotheses concerning the treatment of the Singapore issues by the WTO's membership are described and assessed. The implications of this ...

  8. Recent and current activities of the OECD/NEA Working Group on Fuel Safety (NEA/CSNI). Recent and Current Activities of the Working Group on Fuel Safety (NEA/CSNI)

    International Nuclear Information System (INIS)

    Petit, Marc

    2013-01-01

    The Working Group on Fuel Safety (WGFS) is part of the Committee on the Safety of Nuclear Installations (CSNI) of the Nuclear Energy Agency and has the main mission of advancing the current understanding and addressing fuel safety issues. Recent and current activities of the working group have addressed mainly the loss of coolant accident (LOCA), the reactivity initiated accident (RIA), the fuel safety criteria and leaking fuel issues, as well as Fukushima-related fuel topics. In the area of LOCA, the group issued different documents, the most notable being a very comprehensive state of the art report [NEA/CSNI/R (2009)15]. Regarding RIA, some documents were finalised and issued in the recent years, as well as a state of the art report [NEA/CSNI/R (2010)1]. The question of leaking fuel and how it is handled in the reactors is an activity that is just starting. Of particular interest to people developing new fuel concepts is the Nuclear Fuel Safety Criteria Technical Review - Second Edition [NEA/CSNI/R (2012)3]. This document provides a broad overview of the numerous criteria used in the NEA member countries to demonstrate to safe use of fuel in light water reactors. The WGFS has started discussions about fuel related issues raised by the Fukushima accident, in particular, hydrogen production. New concepts have been proposed to solve these issues but it appears that these concepts will need to go through a long qualification process to assess their adequacy for the different situations considered in the evaluation of fuel safety, from normal operation to accident conditions

  9. Comparison of photospheric electric current and ultraviolet and x-ray emission in a solar active region

    International Nuclear Information System (INIS)

    Haisch, B.M.; Bruner, M.E.; Hagyard, M.J.; Bonnet, R.M.; NASA, Marshall Space Flight Center, Huntsville, AL; ESA, Paris, France)

    1986-01-01

    This paper presents an extensive set of coordinated observations of a solar active region, taking into account spectroheliograms obtained with the aid of the Solar Maximum Mission (SMM) Ultraviolet Spectrometer Polarimeter (UVSP) instrument, SMM soft x-ray polychromator (XRP) raster maps, and high spatial resolution ultraviolet images of the sun in Lyman-alpha and in the 1600 A continuum. These data span together the upper solar atmosphere from the temperature minimum to the corona. The data are compared to maps of the inferred photospheric electric current derived from the Marshall Space Flight Center (MSFC) vector magnetograph observations. Some empirical correlation is found between regions of inferred electric current density and the brightest features in the ultraviolet continuum and to a lesser extent those seen in Lyman-alpha within an active region. 29 references

  10. Remote sub-wavelength focusing of ultrasonically activated Lorentz current

    Science.gov (United States)

    Rekhi, Angad S.; Arbabian, Amin

    2017-04-01

    We propose the use of a combination of ultrasonic and magnetic fields in conductive media for the creation of RF electrical current via the Lorentz force, in order to achieve current generation with extreme sub-wavelength resolution at large depth. We demonstrate the modeling, generation, and measurement of Lorentz current in a conductive solution and show that this current can be localized at a distance of 13 cm from the ultrasonic source to a region about three orders of magnitude smaller than the corresponding wavelength of electromagnetic waves at the same operation frequency. Our results exhibit greater depth, tighter localization, and closer agreement with prediction than previous work on the measurement of Lorentz current in a solution of homogeneous conductivity. The proposed method of RF current excitation overcomes the trade-off between focusing and propagation that is fundamental in the use of RF electromagnetic excitation alone and has the potential to improve localization and depth of operation for RF current-based biomedical applications.

  11. Family stress and parental responses to children's negative emotions: tests of the spillover, crossover, and compensatory hypotheses.

    Science.gov (United States)

    Nelson, Jackie A; O'Brien, Marion; Blankson, A Nayena; Calkins, Susan D; Keane, Susan P

    2009-10-01

    The relations between 4 sources of family stress (marital dissatisfaction, home chaos, parental depressive symptoms, and job role dissatisfaction) and the emotion socialization practice of mothers' and fathers' responses to children's negative emotions were examined. Participants included 101 couples with 7-year-old children. Dyadic analyses were conducted using the Actor-Partner Interdependence Model and relations were tested in terms of the spillover, crossover, and compensatory hypotheses. Results suggest that measures of family stress relate to supportive and nonsupportive parental responses, though many of these relations differ by parent gender. The results are discussed in terms of the 3 theoretical hypotheses, all of which are supported to some degree depending on the family stressor examined.

  12. Reduced Hyperpolarization-Activated Current Contributes to Enhanced Intrinsic Excitability in Cultured Hippocampal Neurons from PrP(-/-) Mice.

    Science.gov (United States)

    Fan, Jing; Stemkowski, Patrick L; Gandini, Maria A; Black, Stefanie A; Zhang, Zizhen; Souza, Ivana A; Chen, Lina; Zamponi, Gerald W

    2016-01-01

    Genetic ablation of cellular prion protein (PrP(C)) has been linked to increased neuronal excitability and synaptic activity in the hippocampus. We have previously shown that synaptic activity in hippocampi of PrP-null mice is increased due to enhanced N-methyl-D-aspartate receptor (NMDAR) function. Here, we focused on the effect of PRNP gene knock-out (KO) on intrinsic neuronal excitability, and in particular, the underlying ionic mechanism in hippocampal neurons cultured from P0 mouse pups. We found that the absence of PrP(C) profoundly affected the firing properties of cultured hippocampal neurons in the presence of synaptic blockers. The membrane impedance was greater in PrP-null neurons, and this difference was abolished by the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker ZD7288 (100 μM). HCN channel activity appeared to be functionally regulated by PrP(C). The amplitude of voltage sag, a characteristic of activating HCN channel current (I h), was decreased in null mice. Moreover, I h peak current was reduced, along with a hyperpolarizing shift in activation gating and slower kinetics. However, neither HCN1 nor HCN2 formed a biochemical complex with PrP(C). These results suggest that the absence of PrP downregulates the activity of HCN channels through activation of a cell signaling pathway rather than through direct interactions. This in turn contributes to an increase in membrane impedance to potentiate neuronal excitability.

  13. CURRENT STATUS OF RESEARCH PROJECT ACTIVITIES IN MEDICAL UNIVERSITIES IN BULGARIA.

    Directory of Open Access Journals (Sweden)

    Svetoslav Garov

    2013-07-01

    Full Text Available Introduction: In Bulgaria there are five medical universities: in the cities of Sofia, Plovdiv, Varna, Pleven and Stara Zagora. Their main mission is training specialists in the fields of medicine and health care, increasing their qualification by means of postgraduate education and performing research activities. One of medical universities’ top priorities is encouraging research activities mainly aimed at preparation and implementation of research projects. Aim: The purpose of our study is to examine the current status of research project activities in Bulgarian medical universities.Material and methods: In order to define the science competitions related to Bulgarian medical universities we have applied a documentary and sociological approach. Results: Research projects that Bulgarian medical universities can apply for are divided into two groups – national and international. The most significant international projects are European ones since Bulgaria is an EU member state and this allows us to participate in such projects. Conclusion: Universities should strive for establishing even better conditions for encouraging application for research projects aimed at developing competent and experienced staff, even though the majority of them may not obtain approval for financing.The changes in the situation regarding Bulgarian science require the implementation and development of more research staff motivated to improve their knowledge and skills in the relevant dynamically changing competition and project field.

  14. Statistical analysis of hypotheses on the cointegrating relations in the I(2) model

    DEFF Research Database (Denmark)

    Johansen, Søren

    2006-01-01

    The cointegrated vector autoregressive model for I(2) variables is a non-linear parametric restriction on the linear I(2) regression model for variables of order I(0), I(1) and I(2). In this paper we discuss non-linear submodels given by smooth parametrizations. We give conditions on the parametr......) and the reformulation is applied to show that some hypotheses on the cointegrating coefficients in the cointegrated I(2) model give asymptotic ¿² inference....

  15. Vorapaxar: The Current Role and Future Directions of a Novel Protease-Activated Receptor Antagonist for Risk Reduction in Atherosclerotic Disease

    OpenAIRE

    Gryka, Rebecca J.; Buckley, Leo F.; Anderson, Sarah M.

    2017-01-01

    Introduction Despite the current standard of care, patients with cardiovascular disease remain at a high risk for recurrent events. Inhibition of thrombin-mediated platelet activation through protease-activated receptor-1 antagonism may provide reductions in atherosclerotic disease beyond those achievable with the current standard of care. Objective Our primary objective is to evaluate the clinical literature regarding the role of vorapaxar (Zontivity?) in the reduction of cardiovascular even...

  16. Cancer risks near nuclear facilities: the importance of research design and explicit study hypotheses.

    Science.gov (United States)

    Wing, Steve; Richardson, David B; Hoffmann, Wolfgang

    2011-04-01

    In April 2010, the U.S. Nuclear Regulatory Commission asked the National Academy of Sciences to update a 1990 study of cancer risks near nuclear facilities. Prior research on this topic has suffered from problems in hypothesis formulation and research design. We review epidemiologic principles used in studies of generic exposure-response associations and in studies of specific sources of exposure. We then describe logical problems with assumptions, formation of testable hypotheses, and interpretation of evidence in previous research on cancer risks near nuclear facilities. Advancement of knowledge about cancer risks near nuclear facilities depends on testing specific hypotheses grounded in physical and biological mechanisms of exposure and susceptibility while considering sample size and ability to adequately quantify exposure, ascertain cancer cases, and evaluate plausible confounders. Next steps in advancing knowledge about cancer risks near nuclear facilities require studies of childhood cancer incidence, focus on in utero and early childhood exposures, use of specific geographic information, and consideration of pathways for transport and uptake of radionuclides. Studies of cancer mortality among adults, cancers with long latencies, large geographic zones, and populations that reside at large distances from nuclear facilities are better suited for public relations than for scientific purposes.

  17. Acute desensitization of acetylcholine and endothelin-1 activated inward rectifier K+ current in myocytes from the cardiac atrioventricular node.

    Science.gov (United States)

    Choisy, Stéphanie C M; James, Andrew F; Hancox, Jules C

    2012-07-06

    The atrioventricular node (AVN) is a vital component of the pacemaker-conduction system of the heart, co-ordinating conduction of electrical excitation from cardiac atria to ventricles and acting as a secondary pacemaker. The electrical behaviour of the AVN is modulated by vagal activity via activation of muscarinic potassium current, IKACh. However, it is not yet known if this response exhibits 'fade' or desensitization in the AVN, as established for the heart's primary pacemaker--the sinoatrial node. In this study, acute activation of IKACh in rabbit single AVN cells was investigated using whole-cell patch clamp at 37 °C. 0.1-1 μM acetylcholine (ACh) rapidly activated a robust IKACh in AVN myocytes during a descending voltage-ramp protocol. This response was inhibited by tertiapin-Q (TQ; 300 nM) and by the M2 muscarinic ACh receptor antagonist AFDX-116 (1 μM). During sustained ACh exposure the elicited IKACh exhibited bi-exponential fade (τf of 2.0 s and τs 76.9 s at -120 mV; 1 μM ACh). 10 nM ET-1 elicited a current similar to IKACh, which faded with a mono-exponential time-course (τ of 52.6 s at -120 mV). When ET-1 was applied following ACh, the ET-1 activated response was greatly attenuated, demonstrating that ACh could desensitize the response to ET-1. For neither ACh nor ET-1 was the rate of current fade dependent upon the initial response magnitude, which is inconsistent with K+ flux mediated changes in electrochemical driving force as the underlying mechanism. Collectively, these findings demonstrate that TQ sensitive inwardly rectifying K+ current in cardiac AVN cells, elicited by M2 muscarinic receptor or ET-1 receptor activation, exhibits fade due to rapid desensitization. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Unilateral prefrontal direct current stimulation effects are modulated by working memory load and gender.

    Science.gov (United States)

    Meiron, Oded; Lavidor, Michal

    2013-05-01

    Recent studies revealed that anodal transcranial direct current stimulation (tDCS) to the left dorsolateral prefrontal cortex (DLPFC) may improve verbal working memory (WM) performance in humans. In the present study, we evaluated executive attention, which is the core of WM capacity, considered to be significantly involved in tasks that require active maintenance of memory representations in interference-rich conditions, and is highly dependent on DLPFC function. We investigated verbal WM accuracy using a WM task that is highly sensitive to executive attention function. We were interested in how verbal WM accuracy may be affected by WM load, unilateral DLPFC stimulation, and gender, as previous studies showed gender-dependent brain activation during verbal WM tasks. We utilized a modified verbal n-Back task hypothesized to increase demands on executive attention. We examined "online" WM performance while participants received transcranial direct current stimulation (tDCS), and implicit learning performance in a post-stimulation WM task. Significant lateralized "online" stimulation effects were found only in the highest WM load condition revealing that males benefit from left DLPFC stimulation, while females benefit from right DLPFC stimulation. High WM load performance in the left DLPFC stimulation was significantly related to post-stimulation recall performance. Our findings support the idea that lateralized stimulation effects in high verbal WM load may be gender-dependent. Further, our post-stimulation results support the idea that increased left hemisphere activity may be important for encoding verbal information into episodic memory as well as for facilitating retrieval of context-specific targets from semantic memory. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. [An increase in allergic diseases in childhood--current hypotheses and possible prevention].

    Science.gov (United States)

    Kurz, Herbert; Riedler, Jose

    2003-01-01

    During the last few decades there has ben a significant rise in the prevalence of allergic diseases such as asthma, hay fever and atopic dermatitis. Epidemiological studies strongly suggest that this increase is real and not due to changes in diagnostic labelling. It has become increasingly clear that a complex interplay between genetic and environmental factors account for this phenomenon. Genetically predisposed individuals are at an increased susceptibility to develop asthma or other allergic diseases when exposed to certain environmental or lifestyle factors. Particularly passive smoking has been shown to increase the risk for asthma in many studies and for atopy at least in some studies. This association is less clear for the exposure to sulfur dioxide, particulate matter, diesel exhaust and ozone. Lifestyle factors like socioeconomic status, sib-ship size, early childhood infections, dietary habits, growing up in antroposophic families or on a farm are more and more realised to be of great relevance for the development of allergic conditions. At the moment, there is a lot of uncertainty about which recommendations should be given for primary prevention. Recent studies have challenged the old paradigma that avoidance of early allergen contact could prevent the development of allergic disease. However, there is consensus that avoidance of smoking during pregnancy and avoidance of passive smoking during childhood should be recommended for primary prevention of asthma.

  20. Molecular Targets for PET Imaging of Activated Microglia: The Current Situation and Future Expectations.

    Science.gov (United States)

    Tronel, Claire; Largeau, Bérenger; Santiago Ribeiro, Maria Joao; Guilloteau, Denis; Dupont, Anne-Claire; Arlicot, Nicolas

    2017-04-11

    Microglia, as cellular mediators of neuroinflammation, are implicated in the pathogenesis of a wide range of neurodegenerative diseases. Positron emission tomography (PET) imaging of microglia has matured over the last 20 years, through the development of radiopharmaceuticals targeting several molecular biomarkers of microglial activation and, among these, mainly the translocator protein-18 kDa (TSPO). Nevertheless, current limitations of TSPO as a PET microglial biomarker exist, such as low brain density, even in a neurodegenerative setting, expression by other cells than the microglia (astrocytes, peripheral macrophages in the case of blood brain barrier breakdown), genetic polymorphism, inducing a variation for most of TSPO PET radiopharmaceuticals' binding affinity, or similar expression in activated microglia regardless of its polarization (pro- or anti-inflammatory state), and these limitations narrow its potential interest. We overview alternative molecular targets, for which dedicated radiopharmaceuticals have been proposed, including receptors (purinergic receptors P2X7, cannabinoid receptors, α7 and α4β2 nicotinic acetylcholine receptors, adenosine 2A receptor, folate receptor β) and enzymes (cyclooxygenase, nitric oxide synthase, matrix metalloproteinase, β-glucuronidase, and enzymes of the kynurenine pathway), with a particular focus on their respective contribution for the understanding of microglial involvement in neurodegenerative diseases. We discuss opportunities for these potential molecular targets for PET imaging regarding their selectivity for microglia expression and polarization, in relation to the mechanisms by which microglia actively participate in both toxic and neuroprotective actions in brain diseases, and then take into account current clinicians' expectations.

  1. Current topics in active and intelligent food packaging for preservation of fresh foods.

    Science.gov (United States)

    Lee, Seung Yuan; Lee, Seung Jae; Choi, Dong Soo; Hur, Sun Jin

    2015-11-01

    The purpose of this review is to provide an overview of current packaging systems, e.g. active packaging and intelligent packaging, for various foods. Active packaging, such as modified atmosphere packaging (MAP), extends the shelf life of fresh produce, provides a high-quality product, reduces economic losses, including those caused by delay of ripening, and improves appearance. However, in active packaging, several variables must be considered, such as temperature control and different gas formulations with different product types and microorganisms. Active packaging refers to the incorporation of additive agents into packaging materials with the purpose of maintaining or extending food product quality and shelf life. Intelligent packaging is emerging as a potential advantage in food processing and is an especially useful tool for tracking product information and monitoring product conditions. Moreover, intelligent packaging facilitates data access and information exchange by altering conditions inside or outside the packaging and product. In spite of these advantages, few of these packaging systems are commercialized because of high cost, strict safety and hygiene regulations or limited consumer acceptance. Therefore more research is needed to develop cheaper, more easily applicable and effective packaging systems for various foods. © 2015 Society of Chemical Industry.

  2. Observation of SOL Current Correlated with MHD Activity in NBI-heated DIII-D Tokamak Discharges

    International Nuclear Information System (INIS)

    Takahashi, H.; Fredrickson, E.D.; Schaffer, M.J.; Austin, M.E.; Evans, T.E.; Lao, L.L.; Watkins, J.G.

    2004-01-01

    This work investigates the potential roles played by the scrape-off-layer current (SOLC) in MHD activity of tokamak plasmas, including effects on stability. SOLCs are found during MHD activity that are: (1) slowly growing after a mode-locking-like event, (2) oscillating in the several kHz range and phase-locked with magnetic and electron temperature oscillations, (3) rapidly growing with a sub-ms time scale during a thermal collapse and a current quench, and (4) spiky in temporal behavior and correlated with spiky features in Da signals commonly identified with the edge localized mode (ELM). These SOLCs are found to be an integral part of the MHD activity, with a propensity to flow in a toroidally non-axisymmetric pattern and with magnitude potentially large enough to play a role in the MHD stability. Candidate mechanisms that can drive these SOLCs are identified: (a) toroidally non-axisymmetric thermoelectric potential, (b) electromotive force (EMF) from MHD activity, and (c) flux swing, both toroidal and poloidal, of the plasma column. An effect is found, stemming from the shear in the field line pitch angle, that mitigates the efficacy of a toroidally non-axisymmetric SOLC to generate a toroidally non-axisymmetric error field. Other potential magnetic consequences of the SOLC are identified: (i) its error field can introduce complications in feedback control schemes for stabilizing MHD activity and (ii) its toroidally non-axisymmetric field can be falsely identified as an axisymmetric field by the tokamak control logic and in equilibrium reconstruction. The radial profile of a SOLC observed during a quiescent discharge period is determined, and found to possess polarity reversals as a function of radial distance

  3. Transient Receptor Potential Vanilloid 4 Activation-Induced Increase in Glycine-Activated Current in Mouse Hippocampal Pyramidal Neurons

    Directory of Open Access Journals (Sweden)

    Mengwen Qi

    2018-02-01

    Full Text Available Background/Aims: Glycine plays an important role in regulating hippocampal inhibitory/ excitatory neurotransmission through activating glycine receptors (GlyRs and acting as a co-agonist of N-methyl-d-aspartate-type glutamate receptors. Activation of transient receptor potential vanilloid 4 (TRPV4 is reported to inhibit hippocampal A-type γ-aminobutyric acid receptor, a ligand-gated chloride ion channel. GlyRs are also ligand-gated chloride ion channels and this paper aimed to explore whether activation of TRPV4 could modulate GlyRs. Methods: Whole-cell patch clamp recording was employed to record glycine-activated current (IGly and Western blot was conducted to assess GlyRs subunits protein expression. Results: Application of TRPV4 agonist (GSK1016790A or 5,6-EET increased IGly in mouse hippocampal CA1 pyramidal neurons. This action was blocked by specific antagonists of TRPV4 (RN-1734 or HC-067047 and GlyR (strychnine, indicating that activation of TRPV4 increases strychnine-sensitive GlyR function in mouse hippocampal pyramidal neurons. GSK1016790A-induced increase in IGly was significantly attenuated by protein kinase C (PKC (BIM II or D-sphingosine or calcium/calmodulin-dependent protein kinase II (CaMKII (KN-62 or KN-93 antagonists but was unaffected by protein kinase A or protein tyrosine kinase antagonists. Finally, hippocampal protein levels of GlyR α1 α2, α3 and β subunits were not changed by treatment with GSK1016790A for 30 min or 1 h, but GlyR α2, α3 and β subunits protein levels increased in mice that were intracerebroventricularly (icv. injected with GSK1016790A for 5 d. Conclusion: Activation of TRPV4 increases GlyR function and expression, and PKC and CaMKII signaling pathways are involved in TRPV4 activation-induced increase in IGly. This study indicates that GlyRs may be effective targets for TRPV4-induced modulation of hippocampal inhibitory neurotransmission.

  4. Numerical studies of active current profile control in the reversed-field pinch

    International Nuclear Information System (INIS)

    Dahlin, J-E; Scheffel, J; Anderson, J K

    2007-01-01

    Quenching of the reversed-field pinch (RFP) dynamo is observed in numerical simulations using current profile control. A novel algorithm employing active feedback of the dynamo field has been utilized. The quasi-steady state achieved represents an important improvement as compared with earlier numerical work and may indicate a direction for the design of future experiments. Both earlier and the novel schemes of feedback control result in quasi-single helicity states. The energy confinement time and poloidal beta are observed to be substantially increased, as compared with the conventional RFP, in both the cases. Different techniques for experimental implementation are discussed

  5. Strategic Classification and Examination of the Development of Current Airline Alliance Activities

    Science.gov (United States)

    Wang, Zhi H.; Evans, Michael

    2002-01-01

    Previous research argues that despite the fact that strategic alliances have become an important feature of the world airline industry, little rigorous analysis has been done on the effects of these alliances. This is partially because there is a lack of precise definitions to specify different types of airline alliances in the literature. This research identifies several categories of airline alliances through a strategic classification of the current alliance activities involving the major airlines for the period 1989 to 1999. The classification enables this research to examine how strategic alliance activities are evolving, particularly to compare how airlines in North America, the European Union and the Asia Pacific region have committed to different alliances. Findings show that there is a significant difference between the number and scope of alliances adopted in the three aviation markets. These findings facilitate research to further analyse the impact of market liberalization on various formations of strategic airline alliances.

  6. The Association between Relational Aggression and Perceived Popularity in Early Adolescence: A Test of Competing Hypotheses

    Science.gov (United States)

    Gangel, Meghan J.; Keane, Susan P.; Calkins, Susan D.; Shanahan, Lilly; O'Brien, Marion

    2017-01-01

    This study examined two competing hypotheses regarding the moderators of the association between relational aggression and peer status in early adolescence. The "mitigation relational aggression" hypothesis examined whether positive social behaviors reduced the negative effects of relational aggression, thus amplifying the association…

  7. Coopersmith Self-Esteem: Two Different Hypothesized Factor Models--Both Acceptable for the Same Data Structure.

    Science.gov (United States)

    Hofmann, Rich; Sherman, Larry

    Using data from 135 sixth-, seventh-, and eighth-graders between 11 and 15 years old attending a middle school in a suburban Southwest Ohio school district, two hypothesized models of the factor structures for the Coopersmith Self-Esteem Inventory were tested. One model represents the original Coopersmith factor structure, and the other model is…

  8. Active load current sharing in fuel cell and battery fed DC motor drive for electric vehicle application

    International Nuclear Information System (INIS)

    Pany, Premananda; Singh, R.K.; Tripathi, R.K.

    2016-01-01

    Highlights: • Load current sharing in FC and battery fed dc drive. • Active current sharing control using LabVIEW. • Detail hardware implementation. • Controller performance is verified through MATLAB simulation and experimental results. - Abstract: In order to reduce the stress on fuel cell based hybrid source fed electric drive system the controller design is made through active current sharing (ACS) technique. The effectiveness of the proposed ACS technique is tested on a dc drive system fed from fuel cell and battery energy sources which enables both load current sharing and source power management. High efficiency and reliability of the hybrid system can be achieved by proper energy conversion and management of power to meet the load demand in terms of required voltage and current. To overcome the slow dynamics feature of FC, a battery bank of adequate power capacity has to be incorporated as FC voltage drops heavily during fast load demand. The controller allows fuel cell to operate in normal load region and draw the excess power from battery. In order to demonstrate the performance of the drive using ACS control strategy different modes of operation of the hybrid source with the static and dynamic behavior of the control system is verified through simulation and experimental results. This control scheme is implemented digitally in LabVIEW with PCI 6251 DAQ I/O interface card. The efficacy of the controller performance is demonstrated in system changing condition supplemented by experimental validation.

  9. The Calcium-Activated Slow AHP: Cutting Through the Gordian Knot

    Directory of Open Access Journals (Sweden)

    Rodrigo eAndrade

    2012-10-01

    Full Text Available The phenomenon known as the slow afterhyperpolarization (sAHP was originally described more than 30 years ago in pyramidal cells as a slow, Ca2+-dependent afterpotential controlling spike frequency adaptation. Subsequent work showed that similar sAHPs were widely expressed in the brain and were mediated by a Ca2+-activated potassium current that was voltage independent, insensitive to most potassium channel blockers, and strongly modulated by neurotransmitters. However the molecular basis for this current has remained poorly understood. The sAHP was initially imagined to reflect the activation of a potassium channel directly gated by Ca2+ but recent studies have begun to question this idea. The sAHP is distinct from the Ca2+-dependent fast and medium AHPs in that it appears to sense cytoplasmic [Ca2+]i and recent evidence implicates proteins of the neuronal calcium sensor family as diffusible cytoplasmic Ca2+ sensors for the sAHP. Translocation of Ca2+-bound sensor to the plasma membrane would then be an intermediate step between Ca2+ and the sAHP channels. Parallel studies strongly suggest that the sAHP current is carried by different potassium channel types depending on the cell type. Finally, the sAHP current is dependent on membrane PtdIns(4,5P2 and Ca2+ appears to gate this current by increasing PtdIns(4,5P2 levels. Because membrane PtdIns(4,5P2 is essential for the activity of many potassium channels, these finding have led us to hypothesize that the sAHP reflects a transient Ca2+-induced increase in the local availability of PtdIns(4,5P2 which then activates a variety of potassium channels. If this view is correct, the sAHP current would not represent a unitary ionic current but the embodiment of a generalized potassium channel gating mechanism. This model can potentially explain the cardinal features of the sAHP, including its cellular heterogeneity, slow kinetics, dependence on cytoplasmic [Ca2+], high temperature-dependence, and

  10. Action of methotrexate and tofacitinib on directly stimulated and bystander-activated lymphocytes.

    Science.gov (United States)

    Piscianz, Elisa; Candilera, Vanessa; Valencic, Erica; Loganes, Claudia; Paron, Greta; De Iudicibus, Sara; Decorti, Giuliana; Tommasini, Alberto

    2016-07-01

    Chronic inflammation associated with autoimmune activation is characteristic of rheumatic diseases from childhood to adulthood. In recent decades, significant improvements in the treatment of these types of disease have been achieved using disease modifying anti-rheumatic drugs (DMARDs), such as methotrexate (MTX) and, more recently, using biologic inhibitors. The recent introduction of kinase inhibitors (for example, tofacitinib; Tofa) further increases the available ARDs. However, there are patients that do not respond to any treatment strategies, for whom combination therapies are proposed. The data regarding the combined action of different drugs is lacking and the knowledge of the mechanisms of ARDs and their actions upon pathogenic lymphocytes, which are hypothesized to sustain disease, is poor. An in vitro model of inflammation was developed in the current study, in which stimulated and unstimulated lymphocytes were cultured together, but tracked separately, to investigate the action of MTX and Tofa on the two populations. By analysing lymphocyte proliferation and activation, and cytokine secretion in the culture supernatants, it was established that, due to the presence of activated cells, unstimulated cells underwent a bystander activation that was modulated by the ARDs. Additionally, varying administration schedules were demonstrated to affect lymphocytes differently in vitro, either directly or via bystander activation. Furthermore, MTX and Tofa exerted different effects; while MTX showed an antiproliferative effect, Tofa marginally effected activation, although only a slight antiproliferative action, which could be potentiated by sequential treatment with MTX. Thus, it was hypothesized that these differences may be exploited in sequential therapeutic strategies, to maximize the anti‑rheumatic effect. These findings are notable and must be accounted for, as bystander‑activated cells in vivo could contribute to the spread of autoimmune activation

  11. A comparison of photospheric electric current and ultraviolet and X-ray emission in a solar active region

    Science.gov (United States)

    Haisch, B. M.; Bruner, M. E.; Hagyard, M. J.; Bonnet, R. M.

    1986-01-01

    This paper presents an extensive set of coordinated observations of a solar active region, taking into account spectroheliograms obtained with the aid of the Solar Maximum Mission (SMM) Ultraviolet Spectrometer Polarimeter (UVSP) instrument, SMM soft X-ray polychromator (XRP) raster maps, and high spatial resolution ultraviolet images of the sun in Lyman-alpha and in the 1600 A continuum. These data span together the upper solar atmosphere from the temperature minimum to the corona. The data are compared to maps of the inferred photospheric electric current derived from the Marshall Space Flight Center (MSFC) vector magnetograph observations. Some empirical correlation is found between regions of inferred electric current density and the brightest features in the ultraviolet continuum and to a lesser extent those seen in Lyman-alpha within an active region.

  12. Family Stress and Parental Responses to Children’s Negative Emotions: Tests of the Spillover, Crossover, and Compensatory Hypotheses

    Science.gov (United States)

    Nelson, Jackie A.; O’Brien, Marion; Blankson, A. Nayena; Calkins, Susan D.; Keane, Susan P.

    2010-01-01

    The relations between 4 sources of family stress (marital dissatisfaction, home chaos, parental depressive symptoms, and job role dissatisfaction) and the emotion socialization practice of mothers’ and fathers’ responses to children’s negative emotions were examined. Participants included 101 couples with 7-year-old children. Dyadic analyses were conducted using the Actor–Partner Interdependence Model and relations were tested in terms of the spillover, crossover, and compensatory hypotheses. Results suggest that measures of family stress relate to supportive and nonsupportive parental responses, though many of these relations differ by parent gender. The results are discussed in terms of the 3 theoretical hypotheses, all of which are supported to some degree depending on the family stressor examined. PMID:19803603

  13. Generalized stability regions of current control for LCL-filtered grid-connected converters without passive or active damping

    DEFF Research Database (Denmark)

    Tang, Yi; Yoon, Changwoo; Zhu, Rongwu

    2015-01-01

    This paper investigates the stability regions of current control for LCL-filtered grid-connected converters, where no active or passive damping is required to stabilize the closed-loop control system. It is already identified in the literature that if the LCL resonance frequency is placed within 1....../6 to 1/2 of the system sampling frequency, the grid current control can be directly used without damping. If the resonance frequency is smaller than 1/6 of the sampling frequency, the converter current control should then be adopted. This paper further extends the analysis to the cases where...... the resonance frequency could be larger than 1/2 of the sampling frequency, and derives the complete stability regions for both grid and converter current control. Interestingly, it is found that for any given LCL-filter design, there will always be one stable current control design without any damping, which...

  14. An empirical evaluation of two theoretically-based hypotheses on the directional association between self-worth and hope.

    Science.gov (United States)

    McDavid, Lindley; McDonough, Meghan H; Smith, Alan L

    2015-06-01

    Fostering self-worth and hope are important goals of positive youth development (PYD) efforts, yet intervention design is complicated by contrasting theoretical hypotheses regarding the directional association between these constructs. Therefore, within a longitudinal design we tested: (1) that self-worth predicts changes in hope (self theory; Harter, 1999), and (2) that hope predicts changes in self-worth (hope theory; Snyder, 2002) over time. Youth (N = 321; Mage = 10.33 years) in a physical activity-based PYD program completed surveys 37-45 days prior to and on the second day and third-to-last day of the program. A latent variable panel model that included autoregressive and cross-lagged paths indicated that self-worth was a significant predictor of change in hope, but hope did not predict change in self-worth. Therefore, the directional association between self-worth and hope is better explained by self-theory and PYD programs should aim to enhance perceptions of self-worth to build perceptions of hope. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  15. Reactor Core Coolability Analysis during Hypothesized Severe Accidents of OPR1000

    International Nuclear Information System (INIS)

    Lee, Yongjae; Seo, Seungwon; Kim, Sung Joong; Ha, Kwang Soon; Kim, Hwan-Yeol

    2014-01-01

    Assessment of the safety features over the hypothesized severe accidents may be performed experimentally or numerically. Due to the considerable time and expenditures, experimental assessment is implemented only to the limited cases. Therefore numerical assessment has played a major role in revisiting severe accident analysis of the existing or newly designed power plants. Computer codes for the numerical analysis of severe accidents are categorized as the fast running integral code and detailed code. Fast running integral codes are characterized by a well-balanced combination of detailed and simplified models for the simulation of the relevant phenomena within an NPP in the case of a severe accident. MAAP, MELCOR and ASTEC belong to the examples of fast running integral codes. Detailed code is to model as far as possible all relevant phenomena in detail by mechanistic models. The examples of detailed code is SCDAP/RELAP5. Using the MELCOR, Carbajo. investigated sensitivity studies of Station Black Out (SBO) using the MELCOR for Peach Bottom BWR. Park et al. conduct regulatory research of the PWR severe accident. Ahn et al. research sensitivity analysis of the severe accident for APR1400 with MELCOR 1.8.4. Lee et al. investigated RCS depressurization strategy and developed a core coolability map for independent scenarios of Small Break Loss-of-Coolant Accident (SBLOCA), SBO, and Total Loss of Feed Water (TLOFW). In this study, three initiating cases were selected, which are SBLOCA without SI, SBO, and TLOFW. The initiating cases exhibit the highest probability of transitioning into core damage according to PSA 1 of OPR 1000. The objective of this study is to investigate the reactor core coolability during hypothesized severe accidents of OPR1000. As a representative indicator, we have employed Jakob number and developed JaCET and JaMCT using the MELCOR simulation. Although the RCS pressures for the respective accident scenarios were different, the JaMCT and Ja

  16. [The evolution of plant life span: facts and hypotheses].

    Science.gov (United States)

    2006-01-01

    There are two different views on the evolution of life forms in Cormophyta: from woody plants to herbaceous ones or in opposite direction - from herbs to trees. In accordance with these views it is supposed that life span in plants changed in the course of evolution from many years (perennials) to few years (annuals, biennials), or went in reverse - from few years to many years. The author discusses the problems of senescence and longevity in Cormophyta in the context of various hypotheses of ageing (programmed death theory, mutation accumulation, antagonistic pleiotropy, disposable soma, genes of ageing, genes of longevity). Special attention is given to bio-morphological aspects of longevity and cases of non-ageing plants ("negative senescence", "potential immortality"). It is proposed to distinguish seven models of simple ontogenesis in Cormophyta that can exemplify the diversity of mechanisms of ageing and longevity. The evolution of life span in plants is considered as an indirect result of natural selection of other characteristics of organisms or as a consequence of fixation of modifications (episelectional evolution). It seems that short life span could emerge several times during evolution of one group of plants, thus favoring its adaptive radiation.

  17. The SEDIBUD (Sediment Budgets in Cold Environments) Programme: Current activities and future key tasks

    Science.gov (United States)

    Beylich, A. A.; Lamoureux, S. F.; Decaulne, A.

    2012-04-01

    Projected climate change in cold regions is expected to alter melt season duration and intensity, along with the number of extreme rainfall events, total annual precipitation and the balance between snowfall and rainfall. Similarly, changes to the thermal balance are expected to reduce the extent of permafrost and seasonal ground frost and increase active layer depths. These effects will undoubtedly change surface environments in cold regions and alter the fluxes of sediments, nutrients and solutes, but the absence of quantitative data and coordinated process monitoring and analysis to understand the sensitivity of the Earth surface environment is acute in cold climate environments. The International Association of Geomorphologists (I.A.G./A.I.G.)SEDIBUD (Sediment Budgets in Cold Environments) Programme was formed in 2005 to address this existing key knowledge gap. SEDIBUD currently has about 400 members worldwide and the Steering Committee of this international programme is composed of ten scientists from eight different countries: Achim A. Beylich (Chair) (Norway), Armelle Decaulne (Secretary) (France), John C. Dixon (USA), Scott F. Lamoureux (Vice-Chair) (Canada), John F. Orwin (Canada), Jan-Christoph Otto (Austria), Irina Overeem (USA), Thorsteinn Saemundsson (Iceland), Jeff Warburton (UK), Zbigniew Zwolinski (Poland). The central research question of this global group of scientists is to: Assess and model the contemporary sedimentary fluxes in cold climates, with emphasis on both particulate and dissolved components. Initially formed as European Science Foundation (ESF) Network SEDIFLUX (2004-2006), SEDIBUD has further expanded to a global group of researchers with field research sites located in polar and alpine regions in the northern and southern hemisphere. Research carried out at each of the close to 50 defined SEDIBUD key test sites varies by programme, logistics and available resources, but typically represent interdisciplinary collaborations of

  18. Differential effects of the transient outward K(+) current activator NS5806 in the canine left ventricle

    DEFF Research Database (Denmark)

    Calloe, Kirstine; Soltysinska, Ewa; Jespersen, Thomas

    2009-01-01

    To examine the electrophysiological and molecular properties of the transient outward current (I(to)) in canine left ventricle using a novel I(to) activator, NS5806, I(to) was measured in isolated epicardial (Epi), midmyocardial (Mid) and endocardial (Endo) cells using whole-cell patch-clamp tech...

  19. Pharmacological modulations of cardiac ultra-rapid and slowly activating delayed rectifier currents: potential antiarrhythmic approaches.

    Science.gov (United States)

    Islam, Mohammed A

    2010-01-01

    Despite the emerging new insights into our understandings of the cellular mechanisms underlying cardiac arrhythmia, medical therapy for this disease remains unsatisfactory. Atrial fibrillation (AF), the most prevalent arrhythmia, is responsible for significant morbidity and mortality. On the other hand, ventricular fibrillation results in sudden cardiac deaths in many instances. Prolongation of cardiac action potential (AP) is a proven principle of antiarrhythmic therapy. Class III antiarrhythmic agents prolong AP and QT interval by blocking rapidly activating delayed rectifier current (I(Kr)). However, I(Kr) blocking drugs carry the risk of life-threatening proarrhythmia. Recently, modulation of atrial-selective ultra-rapid delayed rectifier current (I(Kur)), has emerged as a novel therapeutic approach to treat AF. A number of I(Kur) blockers are being evaluated for the treatment of AF. The inhibition of slowly activating delayed rectifier current (I(Ks)) has also been proposed as an effective and safer antiarrhythmic approach because of its distinguishing characteristics that differ in remarkable ways from other selective class III agents. Selective I(Ks) block may prolong AP duration (APD) at rapid rates without leading to proarrhythmia. This article reviews the pathophysiological roles of I(Kur) and I(Ks) in cardiac repolarization and the implications of newly developed I(Kur) and I(Ks) blocking agents as promising antiarrhythmic approaches. Several recent patents pertinent to antiarrhythmic drug development have been discussed. Further research will be required to evaluate the efficacy and safety of these agents in the clinical setting.

  20. H-convergence for quasi-linear elliptic equations under natural hypotheses on the correctors

    International Nuclear Information System (INIS)

    Bensoussan, A.; Boccardo, L.; Dall'Aglio, A.; Murat, F.

    1995-01-01

    In this paper we study the behavior of the solutions of quasi-linear Dirichlet problems when the principal parts H-converge and when the lower order terms have quadratic growth with respect to the gradient. We show that the limit problem consists of a principal part which is the H-limit of the principal parts and of the lower order term which is constructed from the corresponding terms by using a linear corrector result. We assume only natural hypotheses on the correctors (i.e. L 2 equi-integrability and not L ∞ boundedness). (author)

  1. Geophysical Evolution of Ch Asteroids and Testable Hypotheses for Future Missions

    Science.gov (United States)

    Castillo, J. C.

    2017-12-01

    The main population of asteroids related to meteorites in the collections remains to be explored in situ. Ch asteroids are the only midsized asteroids that display a signature of hydration (besides Pallas) and the spectral connection between Ch asteroids and CM chondrites suggests that the former represent potential parent bodies for the latter. This class of asteroids is particularly interesting because it hosts many objects 100-200 km in size, which are believed to belong to a primordial population of planetesimals. This presentation will explore multiple evolution pathways for Ch-asteroids leading to possible hypotheses on the geological, petrological, and geophysical properties that a disrupted parent body would present to a future mission. This work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA.

  2. Evaluating Hypotheses of Plant Species Invasions on Mediterranean Islands: Inverse Patterns between Alien and Endemic Species

    Directory of Open Access Journals (Sweden)

    Alexander Bjarnason

    2017-08-01

    Full Text Available Invasive alien species cause major changes to ecosystem functioning and patterns of biodiversity, and the main factors involved in invasion success remain contested. Using the Mediterranean island of Crete, Greece as a case study, we suggest a framework for analyzing spatial data of alien species distributions, based on environmental predictors, aiming to gain an understanding of their spatial patterns and spread. Mediterranean islands are under strong ecological pressure from invading species due to their restricted size and increased human impact. Four hypotheses of invasibility, the “propagule pressure hypothesis” (H1, “biotic resistance hypothesis vs. acceptance hypothesis” (H2, “disturbance-mediated hypothesis” (H3, and “environmental heterogeneity hypothesis” (H4 were tested. Using data from alien, native, and endemic vascular plant species, the propagule pressure, biotic resistance vs. acceptance, disturbance-mediated, and environmental heterogeneity hypotheses were tested with Generalized Additive Modeling (GAM of 39 models. Based on model selection, the optimal model includes the positive covariates of native species richness, the negative covariates of endemic species richness, and land area. Variance partitioning between the four hypotheses indicated that the biotic resistance vs. acceptance hypothesis explained the vast majority of the total variance. These results show that areas of high species richness have greater invasibility and support the acceptance hypothesis and “rich-get-richer” distribution of alien species. The negative correlation between alien and endemic species appears to be predominantly driven by altitude, with fewer alien and more endemic species at greater altitudes, and habitat richness. The negative relationship between alien and endemic species richness provides potential for understanding patterns of endemic and alien species on islands, contributing to more effective conservation

  3. Work related perceived stress and muscle activity during standardized computer work among female computer users

    DEFF Research Database (Denmark)

    Larsman, P; Thorn, S; Søgaard, K

    2009-01-01

    The current study investigated the associations between work-related perceived stress and surface electromyographic (sEMG) parameters (muscle activity and muscle rest) during standardized simulated computer work (typing, editing, precision, and Stroop tasks). It was part of the European case......-control study, NEW (Neuromuscular assessment in the Elderly Worker). The present cross-sectional study was based on a questionnaire survey and sEMG measurements among Danish and Swedish female computer users aged 45 or older (n=49). The results show associations between work-related perceived stress...... and trapezius muscle activity and rest during standardized simulated computer work, and provide partial empirical support for the hypothesized pathway of stress induced muscle activity in the association between an adverse psychosocial work environment and musculoskeletal symptoms in the neck and shoulder....

  4. Consumers' evaluations of socially responsible activities in retailing

    NARCIS (Netherlands)

    Herpen, van E.; Pennings, J.M.E.; Meulenberg, M.T.G.

    2003-01-01

    The authors approached Corporate Social Responsibility (CSR) as a process in which particular CSR activities impact on consumers’ store evaluation and trust. They hypothesized that consumers classify CSR activities along two dimensions: (1) the beneficiary of the activity and (2) the intrinsic

  5. Strategies to enhance biologically active-secondary metabolites in cell cultures of Artemisia - current trends.

    Science.gov (United States)

    Ali, Mohammad; Abbasi, Bilal Haider; Ahmad, Nisar; Khan, Haji; Ali, Gul Shad

    2017-11-01

    The genus Artemisia has been utilized worldwide due to its immense potential for protection against various diseases, especially malaria. Artemisia absinthium, previously renowned for its utilization in the popular beverage absinthe, is gaining resurgence due to its extensive pharmacological activities. Like A. annua, this species exhibits strong biological activities like antimalarial, anticancer and antioxidant. Although artemisinin was found to be the major metabolite for its antimalarial effects, several flavonoids and terpenoids are considered to possess biological activities when used alone and also to synergistically boost the bioavailability of artemisinin. However, due to the limited quantities of these metabolites in wild plants, in vitro cultures were established and strategies have been adopted to enhance medicinally important secondary metabolites in these cultures. This review elaborates on the traditional medicinal uses of Artemisia species and explains current trends to establish cell cultures of A. annua and A. absinthium for enhanced production of medicinally important secondary metabolites.

  6. Distinguishing 'Higgs' spin hypotheses using {gamma}{gamma} and WW{sup *} decays

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, John [King' s College London, Theoretical Particle Physics and Cosmology Group, Physics Department, London (United Kingdom); CERN, TH Division, Physics Department, Geneva (Switzerland); Fok, Ricky [York University, Department of Physics and Astronomy, Toronto, ON (Canada); Hwang, Dae Sung [Sejong University, Department of Physics, Seoul (Korea, Republic of); Sanz, Veronica [CERN, TH Division, Physics Department, Geneva (Switzerland); York University, Department of Physics and Astronomy, Toronto, ON (Canada); You, Tevong [King' s College London, Theoretical Particle Physics and Cosmology Group, Physics Department, London (United Kingdom)

    2013-07-15

    The new particle X recently discovered by the ATLAS and CMS Collaborations in searches for the Higgs boson has been observed to decay into {gamma}{gamma}, ZZ{sup *} and WW{sup *}, but its spin and parity, J{sup P}, remain a mystery, with J{sup P} = 0{sup +} and 2{sup +} being open possibilities. We use PYTHIA and Delphes to simulate an analysis of the angular distribution of gg {yields} X {yields} {gamma}{gamma} decays in a full 2012 data set, including realistic background levels. We show that this angular distribution should provide strong discrimination between the possibilities of spin zero and spin two with graviton-like couplings: {proportional_to}3 {sigma} if a conservative symmetric interpretation of the log-likelihood ratio (LLR) test statistic is used, and {proportional_to}6 {sigma} if a less conservative asymmetric interpretation is used. The WW and ZZ couplings of the Standard Model Higgs boson and of a 2{sup +} particle with graviton-like couplings are both expected to exhibit custodial symmetry. We simulate the present ATLAS and CMS search strategies for X {yields} WW{sup *} using PYTHIA and Delphes, and show that their efficiencies in the case of a spin-2 particle with graviton-like couplings are a factor {approx_equal} 1.9 smaller than in the spin-0 case. On the other hand, the ratio of X{sub 2{sup +}} {yields} WW{sup *} and ZZ{sup *} branching ratios is larger than that in the 0{sup +} case by a factor {approx_equal} 1.3. We find that the current ATLAS and CMS results for X {yields} WW{sup *} and X {yields} ZZ{sup *} decays are compatible with custodial symmetry under both the spin-0 and -2 hypotheses, and that the data expected to become available during 2012 are unlikely to discriminate significantly between these possibilities. (orig.)

  7. Positive deviance control-case life history: a method to develop grounded hypotheses about successful long-term avoidance of infection

    Directory of Open Access Journals (Sweden)

    Sandoval Milagros

    2008-03-01

    Full Text Available Abstract Background Prevalence rates for long-term injection drug users in some localities surpass 60% for HIV and 80% for HCV. We describe methods for developing grounded hypotheses about how some injectors avoid infection with either virus. Methods Subjects: 25 drug injectors who have injected drugs 8 – 15 years in New York City. 17 remain without antibody to either HIV or HCV; 3 are double-positives; and 5 are positive for HCV but not HIV. "Staying Safe" methodology compares serostatus groups using detailed biographical timelines and narratives; and information about how subjects maintain access to physical resources and social support; their strategies and tactics to remain safe; how they handle problems of addiction and demands by drug dealers and other drug users; and how their behaviors and strategies do or do not become socially-embedded practices. Grounded theory and life-history analysis techniques compare and contrast doubly-uninfected with those infected with both viruses or only with HCV. Results Themes and initial hypotheses emerging from analyses included two master hypotheses that, if confirmed, should help shape preventive interventions: 1 Staying uninfected is not simply a question of social structure or social position. It involves agency by drug injectors, including sustained hard work and adaptation to changing circumstances. 2 Multiple intentionalities contribute to remaining uninfected. These conscious goals include balancing one's need for drugs and one's income; developing ways to avoid drug withdrawal sickness; avoiding situations where other drug users importune you to share drugs; and avoiding HIV (and perhaps HCV infection. Thus, focusing on a single goal in prevention might be sub-optimal. Other hypotheses specify mechanisms of enacting these intentionalities. One example is finding ways to avoid extreme social ostracism. Conclusion We have identified strategies and tactics that some doubly-uninfected IDUs have

  8. Cross-cultural adaptation and validation of the Behcet’s Disease Current Activity Form in Korea

    Science.gov (United States)

    Choi, Hyo Jin; Seo, Mi Ryoung; Ryu, Hee Jung; Baek, Han Joo

    2015-01-01

    Background/Aims: This study was undertaken to perform a cross-cultural adaptation of the Behcet’s Disease Current Activity Form (BDCAF, version 2006) questionnaire to the Korean language and to evaluate its reliability and validity in a population of Korean patients with Behcet’s disease (BD). Methods: A cross-cultural study was conducted among patients with BD who attended our rheumatology clinic between November 2012 and March 2013. There were 11 males and 35 females in the group. The mean age of the participants was 48.5 years and the mean disease duration was 6.4 years. The first BDCAF questionnaire was completed on arrival and the second assessment was performed 20 minutes later by a different physician. The test-retest reliability was analyzed by computing κ statistics. Kappa scores of > 0.6 indicated a good agreement. To assess the validity, we compared the total BDCAF score with the patient’s/clinician’s perception of disease activity and the Korean version of the Behcet’s Disease Quality of Life (BDQOL). Results: For the test-retest reliability, good agreements were achieved on items such as headache, oral/genital ulceration, erythema, skin pustules, arthralgia, nausea/vomiting/abdominal pain, and diarrhea with altered/frank blood per rectum. Moderate agreement was observed for eye and nervous system involvement. We achieved a fair agreement for arthritis and major vessel involvement. Significant correlations were obtained between the total BDCAF score with the BDQOL and the patient’s/clinician’s perception of disease activity p < 0.05). Conclusions: The Korean version of the BDCAF is a reliable and valid instrument for measuring current disease activity in Korean BD patients. PMID:26354066

  9. NON-NEUTRALIZED ELECTRIC CURRENT PATTERNS IN SOLAR ACTIVE REGIONS: ORIGIN OF THE SHEAR-GENERATING LORENTZ FORCE

    International Nuclear Information System (INIS)

    Georgoulis, Manolis K.; Titov, Viacheslav S.; Mikić, Zoran

    2012-01-01

    Using solar vector magnetograms of the highest available spatial resolution and signal-to-noise ratio, we perform a detailed study of electric current patterns in two solar active regions (ARs): a flaring/eruptive and a flare-quiet one. We aim to determine whether ARs inject non-neutralized (net) electric currents in the solar atmosphere, responding to a debate initiated nearly two decades ago that remains inconclusive. We find that well-formed, intense magnetic polarity inversion lines (PILs) within ARs are the only photospheric magnetic structures that support significant net current. More intense PILs seem to imply stronger non-neutralized current patterns per polarity. This finding revises previous works that claim frequent injections of intense non-neutralized currents by most ARs appearing in the solar disk but also works that altogether rule out injection of non-neutralized currents. In agreement with previous studies, we also find that magnetically isolated ARs remain globally current-balanced. In addition, we confirm and quantify the preference of a given magnetic polarity to follow a given sense of electric currents, indicating a dominant sense of twist in ARs. This coherence effect is more pronounced in more compact ARs with stronger PILs and must be of sub-photospheric origin. Our results yield a natural explanation of the Lorentz force, invariably generating velocity and magnetic shear along strong PILs, thus setting a physical context for the observed pre-eruption evolution in solar ARs.

  10. Identification of Chloride Channels CLCN3 and CLCN5 Mediating the Excitatory Cl− Currents Activated by Sphingosine-1-Phosphate in Sensory Neurons

    Science.gov (United States)

    Qi, Yanmei; Mair, Norbert; Kummer, Kai K.; Leitner, Michael G.; Camprubí-Robles, María; Langeslag, Michiel; Kress, Michaela

    2018-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in numerous physiological and pathophysiological processes. We have previously reported a S1P-induced nocifensive response in mice by excitation of sensory neurons via activation of an excitatory chloride current. The underlying molecular mechanism for the S1P-induced chloride conductance remains elusive. In the present study, we identified two CLCN voltage-gated chloride channels, CLCN3 and CLCN5, which mediated a S1P-induced excitatory Cl− current in sensory neurons by combining RNA-seq, adenovirus-based gene silencing and whole-cell electrophysiological voltage-clamp recordings. Downregulation of CLCN3 and CLCN5 channels by adenovirus-mediated delivery of shRNA dramatically reduced S1P-induced Cl− current and membrane depolarization in sensory neurons. The mechanism of S1P-induced activation of the chloride current involved Rho GTPase but not Rho-associated protein kinase. Although S1P-induced potentiation of TRPV1-mediated ionic currents also involved Rho-dependent process, the lack of correlation of the S1P-activated Cl− current and the potentiation of TRPV1 by S1P suggests that CLCN3 and CLCN5 are necessary components for S1P-induced excitatory Cl− currents but not for the amplification of TRPV1-mediated currents in sensory neurons. This study provides a novel mechanistic insight into the importance of bioactive sphingolipids in nociception. PMID:29479306

  11. Identification of Chloride Channels CLCN3 and CLCN5 Mediating the Excitatory Cl− Currents Activated by Sphingosine-1-Phosphate in Sensory Neurons

    Directory of Open Access Journals (Sweden)

    Yanmei Qi

    2018-02-01

    Full Text Available Sphingosine-1-phosphate (S1P is a bioactive sphingolipid involved in numerous physiological and pathophysiological processes. We have previously reported a S1P-induced nocifensive response in mice by excitation of sensory neurons via activation of an excitatory chloride current. The underlying molecular mechanism for the S1P-induced chloride conductance remains elusive. In the present study, we identified two CLCN voltage-gated chloride channels, CLCN3 and CLCN5, which mediated a S1P-induced excitatory Cl− current in sensory neurons by combining RNA-seq, adenovirus-based gene silencing and whole-cell electrophysiological voltage-clamp recordings. Downregulation of CLCN3 and CLCN5 channels by adenovirus-mediated delivery of shRNA dramatically reduced S1P-induced Cl− current and membrane depolarization in sensory neurons. The mechanism of S1P-induced activation of the chloride current involved Rho GTPase but not Rho-associated protein kinase. Although S1P-induced potentiation of TRPV1-mediated ionic currents also involved Rho-dependent process, the lack of correlation of the S1P-activated Cl− current and the potentiation of TRPV1 by S1P suggests that CLCN3 and CLCN5 are necessary components for S1P-induced excitatory Cl− currents but not for the amplification of TRPV1-mediated currents in sensory neurons. This study provides a novel mechanistic insight into the importance of bioactive sphingolipids in nociception.

  12. Effects of Increasing Neuromuscular Electrical Stimulation Current Intensity on Cortical Sensorimotor Network Activation: A Time Domain fNIRS Study.

    Directory of Open Access Journals (Sweden)

    Makii Muthalib

    Full Text Available Neuroimaging studies have shown neuromuscular electrical stimulation (NMES-evoked movements activate regions of the cortical sensorimotor network, including the primary sensorimotor cortex (SMC, premotor cortex (PMC, supplementary motor area (SMA, and secondary somatosensory area (S2, as well as regions of the prefrontal cortex (PFC known to be involved in pain processing. The aim of this study, on nine healthy subjects, was to compare the cortical network activation profile and pain ratings during NMES of the right forearm wrist extensor muscles at increasing current intensities up to and slightly over the individual maximal tolerated intensity (MTI, and with reference to voluntary (VOL wrist extension movements. By exploiting the capability of the multi-channel time domain functional near-infrared spectroscopy technique to relate depth information to the photon time-of-flight, the cortical and superficial oxygenated (O2Hb and deoxygenated (HHb hemoglobin concentrations were estimated. The O2Hb and HHb maps obtained using the General Linear Model (NIRS-SPM analysis method, showed that the VOL and NMES-evoked movements significantly increased activation (i.e., increase in O2Hb and corresponding decrease in HHb in the cortical layer of the contralateral sensorimotor network (SMC, PMC/SMA, and S2. However, the level and area of contralateral sensorimotor network (including PFC activation was significantly greater for NMES than VOL. Furthermore, there was greater bilateral sensorimotor network activation with the high NMES current intensities which corresponded with increased pain ratings. In conclusion, our findings suggest that greater bilateral sensorimotor network activation profile with high NMES current intensities could be in part attributable to increased attentional/pain processing and to increased bilateral sensorimotor integration in these cortical regions.

  13. Effects of Increasing Neuromuscular Electrical Stimulation Current Intensity on Cortical Sensorimotor Network Activation: A Time Domain fNIRS Study.

    Science.gov (United States)

    Muthalib, Makii; Re, Rebecca; Zucchelli, Lucia; Perrey, Stephane; Contini, Davide; Caffini, Matteo; Spinelli, Lorenzo; Kerr, Graham; Quaresima, Valentina; Ferrari, Marco; Torricelli, Alessandro

    2015-01-01

    Neuroimaging studies have shown neuromuscular electrical stimulation (NMES)-evoked movements activate regions of the cortical sensorimotor network, including the primary sensorimotor cortex (SMC), premotor cortex (PMC), supplementary motor area (SMA), and secondary somatosensory area (S2), as well as regions of the prefrontal cortex (PFC) known to be involved in pain processing. The aim of this study, on nine healthy subjects, was to compare the cortical network activation profile and pain ratings during NMES of the right forearm wrist extensor muscles at increasing current intensities up to and slightly over the individual maximal tolerated intensity (MTI), and with reference to voluntary (VOL) wrist extension movements. By exploiting the capability of the multi-channel time domain functional near-infrared spectroscopy technique to relate depth information to the photon time-of-flight, the cortical and superficial oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentrations were estimated. The O2Hb and HHb maps obtained using the General Linear Model (NIRS-SPM) analysis method, showed that the VOL and NMES-evoked movements significantly increased activation (i.e., increase in O2Hb and corresponding decrease in HHb) in the cortical layer of the contralateral sensorimotor network (SMC, PMC/SMA, and S2). However, the level and area of contralateral sensorimotor network (including PFC) activation was significantly greater for NMES than VOL. Furthermore, there was greater bilateral sensorimotor network activation with the high NMES current intensities which corresponded with increased pain ratings. In conclusion, our findings suggest that greater bilateral sensorimotor network activation profile with high NMES current intensities could be in part attributable to increased attentional/pain processing and to increased bilateral sensorimotor integration in these cortical regions.

  14. Testing multiple statistical hypotheses resulted in spurious associations: a study of astrological signs and health.

    Science.gov (United States)

    Austin, Peter C; Mamdani, Muhammad M; Juurlink, David N; Hux, Janet E

    2006-09-01

    To illustrate how multiple hypotheses testing can produce associations with no clinical plausibility. We conducted a study of all 10,674,945 residents of Ontario aged between 18 and 100 years in 2000. Residents were randomly assigned to equally sized derivation and validation cohorts and classified according to their astrological sign. Using the derivation cohort, we searched through 223 of the most common diagnoses for hospitalization until we identified two for which subjects born under one astrological sign had a significantly higher probability of hospitalization compared to subjects born under the remaining signs combined (P<0.05). We tested these 24 associations in the independent validation cohort. Residents born under Leo had a higher probability of gastrointestinal hemorrhage (P=0.0447), while Sagittarians had a higher probability of humerus fracture (P=0.0123) compared to all other signs combined. After adjusting the significance level to account for multiple comparisons, none of the identified associations remained significant in either the derivation or validation cohort. Our analyses illustrate how the testing of multiple, non-prespecified hypotheses increases the likelihood of detecting implausible associations. Our findings have important implications for the analysis and interpretation of clinical studies.

  15. Shared Genetic Control of Brain Activity During Sleep and Insulin Secretion: A Laboratory-Based Family Study.

    Science.gov (United States)

    Morselli, Lisa L; Gamazon, Eric R; Tasali, Esra; Cox, Nancy J; Van Cauter, Eve; Davis, Lea K

    2018-01-01

    Over the past 20 years, a large body of experimental and epidemiologic evidence has linked sleep duration and quality to glucose homeostasis, although the mechanistic pathways remain unclear. The aim of the current study was to determine whether genetic variation influencing both sleep and glucose regulation could underlie their functional relationship. We hypothesized that the genetic regulation of electroencephalographic (EEG) activity during non-rapid eye movement sleep, a highly heritable trait with fingerprint reproducibility, is correlated with the genetic control of metabolic traits including insulin sensitivity and β-cell function. We tested our hypotheses through univariate and bivariate heritability analyses in a three-generation pedigree with in-depth phenotyping of both sleep EEG and metabolic traits in 48 family members. Our analyses accounted for age, sex, adiposity, and the use of psychoactive medications. In univariate analyses, we found significant heritability for measures of fasting insulin sensitivity and β-cell function, for time spent in slow-wave sleep, and for EEG spectral power in the delta, theta, and sigma ranges. Bivariate heritability analyses provided the first evidence for a shared genetic control of brain activity during deep sleep and fasting insulin secretion rate. © 2017 by the American Diabetes Association.

  16. Zika virus: Current concerns in India

    Directory of Open Access Journals (Sweden)

    Sumit Bhardwaj

    2017-01-01

    Full Text Available With confirmation of Zika virus (ZIKV presence in India, screening of a large number of febrile illness samples yielded only four positive cases. In this review, we address the current concern with context to India. The possible reasons for low level of Zika prevalence in India have been discussed, by extracting some probable explanations from previous experience of chikungunya virus-vector model/studies. In the current context, it is hypothesized that Indian mosquito strains have lower susceptibility gradient/threshold for ZIKV. The very low positivity in the humans also indicates low levels of mosquito-human-mosquito transmission cycle. There is also a need to look for the existence of any such animal cycle/sylvatic involvement in India. The recently detected four cases in India show local transmission of ZIKV suggesting that ZIKV might have been present in India since long time. The earlier vector-virus relationship studies with chikungunya suggested that in due course of time, ZIKV might become a major public health concern in the future.

  17. Nest predation increases with parental activity: separating nest site and parental activity effects.

    OpenAIRE

    Martin, T E; Scott, J; Menge, C

    2000-01-01

    Alexander Skutch hypothesized that increased parental activity can increase the risk of nest predation. We tested this hypothesis using ten open-nesting bird species in Arizona, USA. Parental activity was greater during the nestling than incubation stage because parents visited the nest frequently to feed their young during the nestling stage. However, nest predation did not generally increase with parental activity between nesting stages across the ten study species. Previous investigators h...

  18. ASYMMETRIC SUNSPOT ACTIVITY AND THE SOUTHWARD DISPLACEMENT OF THE HELIOSPHERIC CURRENT SHEET

    International Nuclear Information System (INIS)

    Wang, Y.-M.; Robbrecht, E.

    2011-01-01

    Observations of the interplanetary magnetic field (IMF) have suggested a statistical tendency for the heliospheric current sheet (HCS) to be shifted a few degrees southward of the heliographic equator during the period 1965-2010, particularly in the years near sunspot minimum. Using potential-field source-surface extrapolations and photospheric flux-transport simulations, we demonstrate that this southward displacement follows from Joy's law and the observed hemispheric asymmetry in the sunspot numbers, with activity being stronger in the southern (northern) hemisphere during the declining (rising) phase of cycles 20-23. The hemispheric asymmetry gives rise to an axisymmetric quadrupole field, whose equatorial zone has the sign of the leading-polarity flux in the dominant hemisphere; during the last four cycles, the polarity of the IMF around the equator thus tended to match that of the north polar field both before and after polar field reversal. However, large fluctuations are introduced by the nonaxisymmetric field components, which depend on the longitudinal distribution of sunspot activity in either hemisphere. Consistent with this model, the HCS showed an average northward displacement during cycle 19, when the 'usual' alternation was reversed and the northern hemisphere became far more active than the southern hemisphere during the declining phase of the cycle. We propose a new method for determining the north-south displacement of the HCS from coronal streamer observations.

  19. Sedentary behaviour and physical activity in South Asian women: time to review current recommendations?

    Science.gov (United States)

    Waidyatilaka, Indu; Lanerolle, Pulani; Wickremasinghe, Rajitha; Atukorala, Sunethra; Somasundaram, Noel; de Silva, Angela

    2013-01-01

    Our aims were to describe activity and sedentary behaviours in urban Asian women, with dysglycaemia (diagnosed at recruitment), and without dysglycaemia and examine the relative contribution of these parameters to their glycaemic status. 2800 urban women (30-45 years) were selected by random cluster sampling and screened for dysglycaemia for a final sample of 272 newly diagnosed, drug naive dysglycaemic and 345 normoglycaemic women. Physical activity and sedentary behaviours were assessed by the International Physical Activity Questionnaire (IPAQ). Demographic data, diet and anthropometry were recorded. Logistic regression analysis assessed contribution of all parameters to dysglycaemia and exposure attributable fractions were calculated. The mean energy expenditure on walking (2648.5±1023.7 MET-min/week) and on moderate and vigorous physical activity (4342.3±1768.1 MET-min/week) for normoglycemic women and dysglycaemic women (walking;1046.4±728.4 MET-min/week, moderate and vigorous physical activity; 1086.7±1184.4 MET-min/week) was above the recommended amount of physical activity per week. 94.3% of women spent >1000 MET-minutes/week on activity. Mean sitting and TV time for normoglycaemic and dysglycaemic women were 154.3±62.8, 38.4±31.9, 312.6±116.7 and 140.2±56.5 minutes per day respectively. Physical activity and sedentary behaviour contributed to dysglycaemia after adjustment for family history, diet, systolic blood pressure and Body Mass Index. Exposure attributable fractions for dysglycaemia were; lower physical activity: 78%, higher waist circumference: 94%, and TV viewing time: 85%. Urban South Asian women are at risk of dysglycaemia at lower levels of sedentary behaviour and greater physical activity than western populations, indicating the need for re-visiting current physical activity guidelines for South Asians.

  20. Sedentary behaviour and physical activity in South Asian women: time to review current recommendations?

    Directory of Open Access Journals (Sweden)

    Indu Waidyatilaka

    Full Text Available OBJECTIVE: Our aims were to describe activity and sedentary behaviours in urban Asian women, with dysglycaemia (diagnosed at recruitment, and without dysglycaemia and examine the relative contribution of these parameters to their glycaemic status. METHODS: 2800 urban women (30-45 years were selected by random cluster sampling and screened for dysglycaemia for a final sample of 272 newly diagnosed, drug naive dysglycaemic and 345 normoglycaemic women. Physical activity and sedentary behaviours were assessed by the International Physical Activity Questionnaire (IPAQ. Demographic data, diet and anthropometry were recorded. Logistic regression analysis assessed contribution of all parameters to dysglycaemia and exposure attributable fractions were calculated. RESULTS: The mean energy expenditure on walking (2648.5±1023.7 MET-min/week and on moderate and vigorous physical activity (4342.3±1768.1 MET-min/week for normoglycemic women and dysglycaemic women (walking;1046.4±728.4 MET-min/week, moderate and vigorous physical activity; 1086.7±1184.4 MET-min/week was above the recommended amount of physical activity per week. 94.3% of women spent >1000 MET-minutes/week on activity. Mean sitting and TV time for normoglycaemic and dysglycaemic women were 154.3±62.8, 38.4±31.9, 312.6±116.7 and 140.2±56.5 minutes per day respectively. Physical activity and sedentary behaviour contributed to dysglycaemia after adjustment for family history, diet, systolic blood pressure and Body Mass Index. Exposure attributable fractions for dysglycaemia were; lower physical activity: 78%, higher waist circumference: 94%, and TV viewing time: 85%. CONCLUSIONS: Urban South Asian women are at risk of dysglycaemia at lower levels of sedentary behaviour and greater physical activity than western populations, indicating the need for re-visiting current physical activity guidelines for South Asians.

  1. Measurement technology of RF interference current in high current system

    Science.gov (United States)

    Zhao, Zhihua; Li, Jianxuan; Zhang, Xiangming; Zhang, Lei

    2018-06-01

    Current probe is a detection method commonly used in electromagnetic compatibility. With the development of power electronics technology, the power level of power conversion devices is constantly increasing, and the power current of the electric energy conversion device in the electromagnetic launch system can reach 10kA. Current probe conventionally used in EMC (electromagnetic compatibility) detection cannot meet the test requirements on high current system due to the magnetic saturation problem. The conventional high current sensor is also not suitable for the RF (Radio Frequency) interference current measurement in high current power device due to the high noise level in the output of active amplifier. In this paper, a passive flexible current probe based on Rogowski coil and matching resistance is proposed that can withstand high current and has low noise level, to solve the measurement problems of interference current in high current power converter. And both differential mode and common mode current detection can be easily carried out with the proposed probe because of the probe's flexible structure.

  2. Low noise signal-to-noise ratio enhancing readout circuit for current-mediated active pixel sensors

    International Nuclear Information System (INIS)

    Ottaviani, Tony; Karim, Karim S.; Nathan, Arokia; Rowlands, John A.

    2006-01-01

    Diagnostic digital fluoroscopic applications continuously expose patients to low doses of x-ray radiation, posing a challenge to both the digital imaging pixel and readout electronics when amplifying small signal x-ray inputs. Traditional switch-based amorphous silicon imaging solutions, for instance, have produced poor signal-to-noise ratios (SNRs) at low exposure levels owing to noise sources from the pixel readout circuitry. Current-mediated amorphous silicon pixels are an improvement over conventional pixel amplifiers with an enhanced SNR across the same low-exposure range, but whose output also becomes nonlinear with increasing dosage. A low-noise SNR enhancing readout circuit has been developed that enhances the charge gain of the current-mediated active pixel sensor (C-APS). The solution takes advantage of the current-mediated approach, primarily integrating the signal input at the desired frequency necessary for large-area imaging, while adding minimal noise to the signal readout. Experimental data indicates that the readout circuit can detect pixel outputs over a large bandwidth suitable for real-time digital diagnostic x-ray fluoroscopy. Results from hardware testing indicate that the minimum achievable C-APS output current that can be discerned at the digital fluoroscopic output from the enhanced SNR readout circuit is 0.341 nA. The results serve to highlight the applicability of amorphous silicon current-mediated pixel amplifiers for large-area flat panel x-ray imagers

  3. Improving the Development of Student's Research Questions and Hypotheses in an Introductory Business Research Methods Course

    Science.gov (United States)

    Strangman, Lauria; Knowles, Elizabeth

    2012-01-01

    In an introductory research methods course, students often develop research questions and hypotheses that are vague or confusing, do not contain measurable concepts, and are too narrow in scope or vision. Because of this, the final research projects often fail to provide useful information or address the overall research problem. A Lesson Study…

  4. Emergence of nutrient limitation in tropical dry forests: hypotheses from simulation models

    Science.gov (United States)

    Medvigy, D.; Waring, B. G.; Xu, X.; Trierweiler, A.; Werden, L. K.; Wang, G.; Zhu, Q.; Powers, J. S.

    2017-12-01

    It is unclear to what extent tropical dry forest productivity may be limited by nutrients. Direct assessment of nutrient limitation through fertilization experiments has been rare, and paradigms pertaining to other ecosystems may not extend to tropical dry forests. For example, because dry tropical forests have a lower water supply than moist tropical forests, dry forests can have lower decomposition rates, higher soil carbon and nitrogen concentrations, and a more open nitrogen cycle than moist forests. We used a mechanistic, numerical model to generate hypotheses about nutrient limitation in tropical dry forests. The model dynamically couples ED2 (vegetation dynamics), MEND (biogeochemistry), and N-COM (plant-microbe competition for nutrients). Here, the MEND-component of the model has been extended to include nitrogen (N) and phosphorus (P) cycles. We focus on simulation of sixteen 25m x 25m plots in Costa Rica where a fertilization experiment has been underway since 2015. Baseline simulations are characterized by both nitrogen and phosphorus limitation of vegetation. Fertilization with N and P increased vegetation biomass, with N fertilization having a somewhat stronger effect. Nutrient limitation was also sensitive to climate and was more pronounced during drought periods. Overflow respiration was identified as a key process that mitigated nutrient limitation. These results suggest that, despite often having richer soils than tropical moist forests, tropical dry forests can also become nutrient-limited. If the climate becomes drier in the next century, as is expected for Central America, drier soils may decrease microbial activity and exacerbate nutrient limitation. The importance of overflow respiration underscores the need for appropriate treatment of microbial dynamics in ecosystem models. Ongoing and new nutrient fertilization experiments will present opportunities for testing whether, and how, nutrient limitation may indeed be emerging in tropical dry

  5. One year after the Zika virus outbreak in Brazil: from hypotheses to evidence

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Antunes de Brito

    Full Text Available Abstract Zika virusis an arbovirus of the Flaviviridae family with two major strains, an Asian and an African strain. The main vectors involved in the transmission of Zika virus are the Aedes aegypti and Aedes albopictus mosquitoes. Despite its identification, discovered in 1947 in the Zika forest in Uganda, only isolated and sporadic occurrences of human infection were reported within a largely asymptomatic proportion of individuals. The first reported outbreak occurred in 2007 in the Yap Island, which belongs to the Federated States of Micronesia in the Pacific Ocean, and in French Polynesia, where high attack rates occurred and the first cases of associated Guillain-Barré syndrome were reported. From November 2014 to early 2015, the Northeast states of Brazil reported the first outbreaks of Zika virus infection, with laboratory confirmation of Zika virus circulation in April 2015. In the second quarter of 2015, the association between Zika virus infection and neurological symptoms was confirmed in adults. Moreover, in October 2015 a novel suspicion was raised based on clinical and epidemiological observations: that an association between Zika virus infection and neonatal microcephaly may exist. A year after the first reports on Zika virus in Brazil, many hypotheses and much evidence on the patterns of involvement of the disease and its complications have been produced, both in this country and others; other hypotheses still need to be clarified. This review is a synthesis of a new chapter in the history of medicine; it outlines the main results produced.

  6. Can manipulations of cognitive load be used to test evolutionary hypotheses?

    Science.gov (United States)

    Barrett, H Clark; Frederick, David A; Haselton, Martie G; Kurzban, Robert

    2006-09-01

    D. DeSteno, M. Y. Bartlett, J. Braverman, and P. Salovey proposed that if sex-differentiated responses to infidelity are evolved, then they should be automatic, and therefore cognitive load should not attenuate them. DeSteno et al. found smaller sex differences in response to sexual versus emotional infidelity among participants under cognitive load, an effect interpreted as evidence against the evolutionary hypothesis. This logic is faulty. Cognitive load probably affects mechanisms involved in simulating infidelity experiences, thus seriously challenging the usefulness of cognitive load manipulations in testing hypotheses involving simulation. The method also entails the assumption that evolved jealousy mechanisms are necessarily automatic, an assumption not supported by theory or evidence. Regardless of how the jealousy debate is eventually settled, cognitive load manipulations cannot rule out the operation of evolved mechanisms. ((c) 2006 APA, all rights reserved).

  7. Childhood asthma and physical activity

    DEFF Research Database (Denmark)

    Lochte, Lene; Nielsen, Kim G; Petersen, Poul Erik

    2016-01-01

    BACKGROUND: Childhood asthma is a global problem affecting the respiratory health of children. Physical activity (PA) plays a role in the relationship between asthma and respiratory health. We hypothesized that a low level of PA would be associated with asthma in children and adolescents. The obj......BACKGROUND: Childhood asthma is a global problem affecting the respiratory health of children. Physical activity (PA) plays a role in the relationship between asthma and respiratory health. We hypothesized that a low level of PA would be associated with asthma in children and adolescents......; however, there was some heterogeneity among the studies. This review reveals a critical need for future longitudinal assessments of low PA, its mechanisms, and its implications for incident asthma in children. The systematic review was prospectively registered at PROSPERO (registration number: CRD...

  8. An 11 μ w, two-electrode transimpedance biosignal amplifier with active current feedback stabilization.

    Science.gov (United States)

    Inan, O T; Kovacs, G T A

    2010-04-01

    A novel two-electrode biosignal amplifier circuit is demonstrated by using a composite transimpedance amplifier input stage with active current feedback. Micropower, low gain-bandwidth product operational amplifiers can be used, leading to the lowest reported overall power consumption in the literature for a design implemented with off-the-shelf commercial integrated circuits (11 μW). Active current feedback forces the common-mode input voltage to stay within the supply rails, reducing baseline drift and amplifier saturation problems that can be present in two-electrode systems. The bandwidth of the amplifier extends from 0.05-200 Hz and the midband voltage gain (assuming an electrode-to-skin resistance of 100 kΩ) is 48 dB. The measured output noise level is 1.2 mV pp, corresponding to a voltage signal-to-noise ratio approaching 50 dB for a typical electrocardiogram (ECG) level input of 1 mVpp. Recordings were taken from a subject by using the proposed two-electrode circuit and, simultaneously, a three-electrode standard ECG circuit. The residual of the normalized ensemble averages for both measurements was computed, and the power of this residual was 0.54% of the power of the standard ECG measurement output. While this paper primarily focuses on ECG applications, the circuit can also be used for amplifying other biosignals, such as the electroencephalogram.

  9. Current activities in development of PIE techniques in JMTR hot laboratory

    International Nuclear Information System (INIS)

    Ishii, Toshimitsu; Ohmi, Masao; Shimizu, Michio; Kaji, Yoshiyuki; Ueno, Fumiyoshi

    2006-01-01

    A wide variety of post-irradiation examinations (PIEs) for research and development of nuclear fuels and materials to be utilized in nuclear field has been carried out since 1971 in three kinds of β-γ hot cells; concrete, lead and steel cells in the JMTR Hot Laboratory (JMTR HL) associated with the Japan Materials Testing Reactor (JMTR). In addition to PIEs, the re-capsuling work including re-instrumentation was also conducted for the power ramping tests of the irradiated LWR fuels using Boiling Water Capsule (BOCA). Recently, new PIE techniques are required for the advanced irradiation studies. In this paper, the irradiation assisted stress corrosion cracking (IASCC) growth test technique of irradiated in-core structural materials and the remote operation technique of the atomic force microscope (AFM) are described as JMTR HL's current activities in the development of new PIE techniques. (author)

  10. Single Phase Current-Source Active Rectifier for Traction: Control System Design and Practical Problems

    Directory of Open Access Journals (Sweden)

    Jan Michalik

    2006-01-01

    Full Text Available This research has been motivated by industrial demand for single phase current-source active rectifier dedicated for reconstruction of older types of dc machine locomotives. This paper presents converters control structure design and simulations. The proposed converter control is based on the mathematical model and due to possible interaction with railway signaling and required low switching frequency employs synchronous PWM. The simulation results are verified by experimental tests performed on designed laboratory prototype of power of 7kVA

  11. In vitro - in vivo correlations for endocrine activity of a mixture of currently used pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Taxvig, Camilla, E-mail: camta@food.dtu.dk [Division of Toxicology and Risk Assessment, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg (Denmark); Hadrup, Niels; Boberg, Julie; Axelstad, Marta [Division of Toxicology and Risk Assessment, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg (Denmark); Bossi, Rossana [Department of Environmental Science, Aarhus University, DK-4000 Roskilde (Denmark); Bonefeld-Jørgensen, Eva Cecilie [Department of Public Health, University of Aarhus, DK-8000 Aarhus C (Denmark); Vinggaard, Anne Marie [Division of Toxicology and Risk Assessment, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg (Denmark)

    2013-11-01

    Two pesticide mixtures were investigated for potential endocrine activity. Mix 3 consisted of bitertanol, propiconazole, and cypermethrin, and Mix 5 included malathion and terbuthylazine in addition to the three pesticides in Mix 3. All five single pesticides and the two mixtures were investigated for their ability to affect steroidogenesis in vitro in H295R cells. The pesticides alone and both mixtures affected steroidogenesis with both mixtures causing increase in progesterone and decrease in testosterone. For Mix 5 an increase in estradiol was seen as well, indicating increased aromatase activity. The two mixtures were also investigated in pregnant rats dosed from gestational day 7 to 21, followed by examination of dams and fetuses. Decreased estradiol and reduced placental testosterone were seen in dams exposed to Mix 5. Also a significant increase in aromatase mRNA-levels in female adrenal glands was found for Mix5. However, either of the two mixtures showed any effects on fetal hormone levels in plasma or testis, or on anogenital distance. Overall, potential aromatase induction was found for Mix 5 both in vitro and in vivo, but not for Mix 3, an effect likely owed to terbuthylazine in Mix 5. However, the hormonal responses in vitro were only partly reflected in vivo, probably due to some toxicokinetic issues, as the pesticide levels in the amniotic fluid also were found to be negatively affected by the number of compounds present in the mixtures. Nonetheless, the H295R assay gives hints on conceivable interference with steroidogenesis, thus generating hypotheses on in vivo effects. - Highlights: • The study examines the endocrine disrupting potential of mixtures of pesticides. • All single pesticides and both mixtures affected steroidogenesis in vitro. • Potential aromatase induction was found for Mix 5 both in vitro and in vivo. • The hormonal responses in vitro were only partly reflected in vivo.

  12. Physiological consequences of transient outward K(+) current activation during heart failure in the canine left ventricle

    DEFF Research Database (Denmark)

    Cordeiro, Jonathan M; Callø, Kirstine; Moise, N Sydney

    2012-01-01

    .7±1.4pA/pF after 5weeks, +50mV). Current decay as well as recovery of I(to) from inactivation progressively slowed with the development of heart failure. Reduction of I(to) density was paralleled by a reduction in phase 1 magnitude, epicardial action potential notch and J wave amplitude recorded from......Background: Remodeling of ion channel expression is well established in heart failure (HF). We determined the extent to which I(to) is reduced in tachypacing-induced HF and assessed the ability of an I(to) activator (NS5806) to recover this current. Method and results: Whole-cell patch clamp...

  13. Fear of knowledge: Clinical hypotheses in diagnostic and prognostic reasoning.

    Science.gov (United States)

    Chiffi, Daniele; Zanotti, Renzo

    2017-10-01

    Patients are interested in receiving accurate diagnostic and prognostic information. Models and reasoning about diagnoses have been extensively investigated from a foundational perspective; however, for all its importance, prognosis has yet to receive a comparable degree of philosophical and methodological attention, and this may be due to the difficulties inherent in accurate prognostics. In the light of these considerations, we discuss a considerable body of critical thinking on the topic of prognostication and its strict relations with diagnostic reasoning, pointing out the distinction between nosographic and pathophysiological types of diagnosis and prognosis, underlying the importance of the explication and explanation processes. We then distinguish between various forms of hypothetical reasoning applied to reach diagnostic and prognostic judgments, comparing them with specific forms of abductive reasoning. The main thesis is that creative abduction regarding clinical hypotheses in diagnostic process is very unlikely to occur, whereas this seems to be often the case for prognostic judgments. The reasons behind this distinction are due to the different types of uncertainty involved in diagnostic and prognostic judgments. © 2016 John Wiley & Sons, Ltd.

  14. Mechanisms of exercise-induced bronchoconstriction in athletes: Current perspectives and future challenges.

    Science.gov (United States)

    Couto, M; Kurowski, M; Moreira, A; Bullens, D M A; Carlsen, K-H; Delgado, L; Kowalski, M L; Seys, S F

    2018-01-01

    The evidence of exercise-induced bronchoconstriction (EIB) without asthma (EIBw A ) occurring in athletes led to speculate about different endotypes inducing respiratory symptoms within athletes. Classical postulated mechanisms for bronchial obstruction in this population include the osmotic and the thermal hypotheses. More recently, the presence of epithelial injury and inflammation in the airways of athletes was demonstrated. In addition, neuronal activation has been suggested as a potential modulator of bronchoconstriction. Investigation of these emerging mechanisms is of major importance as EIB is a significant problem for both recreational and competitive athletes and is the most common chronic condition among Olympic athletes, with obvious implications for their competing performance, health and quality of life. Hereby, we summarize the latest achievements in this area and identify the current gaps of knowledge so that future research heads toward better defining the etiologic factors and mechanisms involved in development of EIB in elite athletes as well as essential aspects to ultimately propose preventive and therapeutic measures. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

  15. Localization of endocardial ectopic activity by means of noninvasive endocardial surface current density reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Lai Dakun; Liu Chenguang; Eggen, Michael D; He Bin [Department of Biomedical Engineering, University of Minnesota, MN (United States); Iaizzo, Paul A, E-mail: binhe@umn.edu [Department of Surgery, University of Minnesota, MN (United States)

    2011-07-07

    Localization of the source of cardiac ectopic activity has direct clinical benefits for determining the location of the corresponding ectopic focus. In this study, a recently developed current-density (CD)-based localization approach was experimentally evaluated in noninvasively localizing the origin of the cardiac ectopic activity from body-surface potential maps (BSPMs) in a well-controlled experimental setting. The cardiac ectopic activities were induced in four well-controlled intact pigs by single-site pacing at various sites within the left ventricle (LV). In each pacing study, the origin of the induced ectopic activity was localized by reconstructing the CD distribution on the endocardial surface of the LV from the measured BSPMs and compared with the estimated single moving dipole (SMD) solution and precise pacing site (PS). Over the 60 analyzed beats corresponding to ten pacing sites (six for each), the mean and standard deviation of the distance between the locations of maximum CD value and the corresponding PSs were 16.9 mm and 4.6 mm, respectively. In comparison, the averaged distance between the SMD locations and the corresponding PSs was slightly larger (18.4 {+-} 3.4 mm). The obtained CD distribution of activated sources extending from the stimulus site also showed high consistency with the endocardial potential maps estimated by a minimally invasive endocardial mapping system. The present experimental results suggest that the CD method is able to locate the approximate site of the origin of a cardiac ectopic activity, and that the distribution of the CD can portray the propagation of early activation of an ectopic beat.

  16. Direct current (DC) resistivity and induced polarization (IP) monitoring of active layer dynamics at high temporal resolution

    DEFF Research Database (Denmark)

    Doetsch, Joseph; Ingeman-Nielsen, Thomas; Christiansen, Anders V.

    2015-01-01

    With permafrost thawing and changes in active layer dynamics induced by climate change, interactions between biogeochemical and thermal processes in the ground are of great importance. Here, active layer dynamics have been monitored using direct current (DC) resistivity and induced polarization (IP...... in resistivity. While the freezing horizon generally moves deeper with time, some variations in the freezing depth are observed along the profile. Comparison with depth-specific soil temperature indicates an exponential relationship between resistivity and below-freezing temperature. Time-lapse inversions...

  17. Using active power filter to compensate the current component of asymmetrical non-linear load in the four wire network

    Directory of Open Access Journals (Sweden)

    Руслан Володимирович Власенко

    2016-07-01

    Full Text Available Electricity quality improving is extremely relevant nowadays. With such industrial loads as induction motors, induction furnaces, welding machines, controlled or uncontrolled rectifiers, frequency converters and others reactive power, harmonics and unbalance are generated in power grid. Reactive power, higher harmonic currents and asymmetry loads influence the functioning of electric devices and electrical mains. An effective technical solution is the use of new compensating devices, that is active power filters. The emergence of consumers with a unit capacity of four wire networks requires a new approach to building system control active power filter. When designing the active power filter control system the current flowing in the neutral wire must be taken into account. To assess the power balance in the four wire active power filter, scientists have proposed to apply pqr theory of power based on the Clarke transformation. There are different topologies of three-phase four wire active power filters. A visual simulation of Matlab / Simulink model with an active power filter based on pqr theory of power has been created. A method of pulse width modulation with four control channels was used as pulses forming systems with transistor keys. Operating conditions of three-phase four wire active power filter with asymmetry, non-sinosoidal voltage source and asymmetric load have been studied. The correction taking into account the means improving the active power filter has been offered as pqr theory of power does not take into account non-sinosoidal voltage

  18. Effect of water activity on rates of serpentinization of olivine.

    Science.gov (United States)

    Lamadrid, Hector M; Rimstidt, J Donald; Schwarzenbach, Esther M; Klein, Frieder; Ulrich, Sarah; Dolocan, Andrei; Bodnar, Robert J

    2017-07-14

    The hydrothermal alteration of mantle rocks (referred to as serpentinization) occurs in submarine environments extending from mid-ocean ridges to subduction zones. Serpentinization affects the physical and chemical properties of oceanic lithosphere, represents one of the major mechanisms driving mass exchange between the mantle and the Earth's surface, and is central to current origin of life hypotheses as well as the search for microbial life on the icy moons of Jupiter and Saturn. In spite of increasing interest in the serpentinization process by researchers in diverse fields, the rates of serpentinization and the controlling factors are poorly understood. Here we use a novel in situ experimental method involving olivine micro-reactors and show that the rate of serpentinization is strongly controlled by the salinity (water activity) of the reacting fluid and demonstrate that the rate of serpentinization of olivine slows down as salinity increases and H 2 O activity decreases.

  19. Effect of water activity on rates of serpentinization of olivine

    Science.gov (United States)

    Lamadrid, Hector M.; Rimstidt, J. Donald; Schwarzenbach, Esther M.; Klein, Frieder; Ulrich, Sarah; Dolocan, Andrei; Bodnar, Robert J.

    2017-07-01

    The hydrothermal alteration of mantle rocks (referred to as serpentinization) occurs in submarine environments extending from mid-ocean ridges to subduction zones. Serpentinization affects the physical and chemical properties of oceanic lithosphere, represents one of the major mechanisms driving mass exchange between the mantle and the Earth's surface, and is central to current origin of life hypotheses as well as the search for microbial life on the icy moons of Jupiter and Saturn. In spite of increasing interest in the serpentinization process by researchers in diverse fields, the rates of serpentinization and the controlling factors are poorly understood. Here we use a novel in situ experimental method involving olivine micro-reactors and show that the rate of serpentinization is strongly controlled by the salinity (water activity) of the reacting fluid and demonstrate that the rate of serpentinization of olivine slows down as salinity increases and H2O activity decreases.

  20. Combining soft decision algorithms and scale-sequential hypotheses pruning for object recognition

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V.P.; Manolakos, E.S. [Northeastern Univ., Boston, MA (United States)

    1996-12-31

    This paper describes a system that exploits the synergy of Hierarchical Mixture Density (HMD) estimation with multiresolution decomposition based hypothesis pruning to perform efficiently joint segmentation and labeling of partially occluded objects in images. First we present the overall structure of the HMD estimation algorithm in the form of a recurrent neural network which generates the posterior probabilities of the various hypotheses associated with the image. Then in order to reduce the large memory and computation requirement we propose a hypothesis pruning scheme making use of the orthonormal discrete wavelet transform for dimensionality reduction. We provide an intuitive justification for the validity of this scheme and present experimental results and performance analysis on real and synthetic images to verify our claims.

  1. Age and motives for volunteering: testing hypotheses derived from socioemotional selectivity theory.

    Science.gov (United States)

    Okun, Morris A; Schultz, Amy

    2003-06-01

    Following a meta-analysis of the relations between age and volunteer motives (career, understanding, enhancement, protective, making friends, social, and values), the authors tested hypotheses derived from socioemotional selectivity theory regarding the effects of age on these volunteer motives. The Volunteer Functions Inventory was completed by 523 volunteers from 2 affiliates of the International Habitat for Humanity. Multiple regression analyses revealed, as predicted, that as age increases, career and understanding volunteer motivation decrease and social volunteer motivation increases. Contrary to expectations, age did not contribute to the prediction of enhancement, protective, and values volunteer motivations and the relation between age and making friends volunteer motivation was nonlinear. The results were discussed in the context of age-differential and age-similarity perspectives on volunteer motivation.

  2. Do Job Demands of Chinese Manufacturing Employees Predict Positive or Negative Outcomes? A Test of Competing Hypotheses.

    Science.gov (United States)

    Cheung, Janelle H; Sinclair, Robert R; Shi, Junqi; Wang, Mo

    2015-12-01

    Karasek's job demands-control (JDC) model posits that job control can buffer against the harmful effects of demands experienced by employees. A large volume of JDC research has obtained support for the main effects of demands and control, but not the interactive effects. Recent research on the challenge-hindrance stressors framework, however, found that work stressors may not always be deleterious, suggesting alternative hypotheses about the effects of demands and control. The present study therefore examined competing hypotheses concerning the effects of job demands on occupational health outcomes. Using a sample of 316 employees in a Chinese manufacturing company, we found that, consistent with the challenge-hindrance framework, production demands were challenge stressors associated with favourable outcomes (i.e. job satisfaction and psychological well-being). In addition, results showed that the interactive role of job control depended on the nature of outcome variables. Future recommendations and implications of findings are discussed. Copyright © 2014 John Wiley & Sons, Ltd.

  3. A reading of the crisis of prevention activities: current paradoxes and future challenges

    Directory of Open Access Journals (Sweden)

    Rodolfo Andrade de Gouveia Vilela

    2017-12-01

    Full Text Available Introduction: The activity of occupational health and safety professionals is in a paradoxical situation considering, among other aspects, the productivity context, which gives low priority to safety and health, the limitation imposed by the hegemonic conceptual references in the field, the limitation of these professionals’ power to act and the highly conflicting and complex character of the occupational world. Objective: In essay form, the article, in dialog with the literature of the field, proposes to reflect on the impasses and challenges of the prevention field. Method: The reflections are based on the experience of the authors both in the practical area as also in research, teaching and extension activities in the field of health surveillance and workers’ safety. Results: Even though this field of activity has been recognized as a specialized and legal area for more than 40 years in the country, the magnitude of the data concerning occupational and industrial accidents reveals the limitations and difficulties that these professionals face, and justifies the importance of the analysis of current practices in order to understand the contradictions that lie at the root of the difficulties to achieve prevention. Conclusion: Citizens could pressure corporations to improve their safety practices and concepts. State can also be pressured to create new safety policies.

  4. [Co-occurrence of anxiety and autism. The social error and allostatic load hypotheses].

    Science.gov (United States)

    Paula-Perez, Isabel

    2013-02-22

    INTRODUCTION. The concept of comorbidity in neurodevelopmental disorders like autism is sometimes ambiguous. The co-occurrence of anxiety and autism is clinically significant, yet it is not always easy to determine whether it is a 'real' comorbidity, where the two comorbid conditions are phenotypically and aetiologically identical to what that anxiety would mean in persons with a neurotypical development, whether it is an anxiety that has been phenotypically modified by the pathological processes of the autism spectrum disorders, thus resulting in a specific variant of these latter, or whether we are dealing with a false comorbidity resulting from rather inaccurate differential diagnoses. DEVELOPMENT. The article puts forward two hypotheses to explain this co-occurrence, which provide each other with feedback and are little more than our reflections on the scientific evidence we have available today, but expressed aloud. The first is the 'social error' hypothesis, which considers that the maladjustments in the social behaviour of persons with autism (which arises from alterations affecting the processes involved in social cognition) help to aggravate anxiety in autism. The second hypothesis, referring to allostatic load, holds that anxiety is a response to chronic stress, wear or exhaustion that is produced by the hyperactivation of certain structures in the limbic system. CONCLUSIONS. The prototypical manifestations of anxiety present in the person with autism are not always related with the same biopsychosocial variables as those observed in persons without autism. Evidence points to hyper-reactive flee-or-fight responses (hypervigilance) when the person finds him or herself outside their comfort zone, and supports the hypotheses of 'social error' and of decompensation of the allostatic mechanism that makes it possible to cope with stress.

  5. Artificial light and nocturnal activity in gammarids

    Directory of Open Access Journals (Sweden)

    Elizabeth K. Perkin

    2014-03-01

    Full Text Available Artificial light is gaining attention as a potential stressor to aquatic ecosystems. Artificial lights located near streams increase light levels experienced by stream invertebrates and we hypothesized light would depress night drift rates. We also hypothesized that the effect of light on drift rates would decrease over time as the invertebrates acclimated to the new light level over the course of one month’s exposure. These hypotheses were tested by placing Gammarus spp. in eight, 75 m × 1 m artificial flumes. One flume was exposed to strong (416 lx artificial light at night. This strong light created a gradient between 4.19 and 0.04 lx over the neighboring six artificial flumes, while a control flume was completely covered with black plastic at night. Night-time light measurements taken in the Berlin area confirm that half the flumes were at light levels experienced by urban aquatic invertebrates. Surprisingly, no light treatment affected gammarid drift rates. In contrast, physical activity measurements of in situ individually caged G. roeseli showed they increased short-term activity levels in nights of complete darkness and decreased activity levels in brightly lit flumes. Both nocturnal and diurnal drift increased, and day drift rates were unexpectadly higher than nocturnal drift.

  6. Quantitative analysis of dental microwear in hadrosaurid dinosaurs, and the implications for hypotheses of jaw mechanics and feeding

    Science.gov (United States)

    Williams, Vincent S.; Barrett, Paul M.; Purnell, Mark A.

    2009-01-01

    Understanding the feeding mechanisms and diet of nonavian dinosaurs is fundamental to understanding the paleobiology of these taxa and their role in Mesozoic terrestrial ecosystems. Various methods, including biomechanical analysis and 3D computer modeling, have been used to generate detailed functional hypotheses, but in the absence of either direct observations of dinosaur feeding behavior, or close living functional analogues, testing these hypotheses is problematic. Microscopic scratches that form on teeth in vivo during feeding are known to record the relative motion of the tooth rows to each other during feeding and to capture evidence of tooth–food interactions. Analysis of this dental microwear provides a powerful tool for testing hypotheses of jaw mechanics, diet, and trophic niche; yet, quantitative analysis of microwear in dinosaurs has not been attempted. Here, we show that analysis of tooth microwear orientation provides direct evidence for the relative motions of jaws during feeding in hadrosaurid ornithopods, the dominant terrestrial herbivores of the Late Cretaceous. Statistical testing demonstrates that Edmontosaurus teeth preserve 4 distinct sets of scratches in different orientations. In terms of jaw mechanics, these data indicate an isognathic, near-vertical posterodorsal power stroke during feeding; near-vertical jaw opening; and propalinal movements in near anterior and near posterior directions. Our analysis supports the presence of a pleurokinetic hinge, and the straightness and parallelism of scratches indicate a tightly controlled occlusion. The dominance of scratched microwear fabrics suggests that Edmontosaurus was a grazer rather than a browser. PMID:19564603

  7. Direct current (DC) resistivity and Induced Polarization (IP) monitoring of active layer dynamics at high temporal resolution

    DEFF Research Database (Denmark)

    Doetsch, J.; Fiandaca, G.; Ingeman-Nielsen, Thomas

    2015-01-01

    With permafrost thawing and changes in active layer dynamics induced by climate change, interactions between biogeochemical and thermal processes in the ground are of great importance. Here, active layer dynamics have been monitored using direct current (DC) resistivity and induced polarization (IP...... the soil freezing as a strong increase in resistivity. While the freezing horizon generally moves deeper with time, some variations in the freezing depth are observed along the profile. Comparison with depth-specific soil temperature indicates an exponential relationship between resistivity and below...

  8. Current physical activity improves balance control during sensory conflicting conditions in older adults.

    Science.gov (United States)

    Buatois, S; Gauchard, G C; Aubry, C; Benetos, A; Perrin, P

    2007-01-01

    Aging process is characterized by difficulties in ensuring balance control, especially in conditions of reduced or conflicting sensory information, leading to an increased risk of falling. Conversely, the practise of physical activities (PA) has been recognized as a good approach to improve the quality of balance control. This study aimed to investigate the influence of current and/or past PA on balance-related neurosensorial organization in older adults on the maintenance of the upright stance, especially during sensory conflicting situations. Postural control was evaluated by means of the Sensory Organization Test on 130 healthy noninstitutionalized volunteers aged over 65, split into four groups according to the presence or absence of PA before or after retirement. Subjects who practised PA for a long time (Gr1) and subjects who started PA after retirement (Gr2) displayed the best postural performances and better managed sensory conflicting situations compared to subjects who had stopped PA for many years (Gr3) and subjects who had never practised PA (Gr4). Multiple regression analyses revealed that current PA was the major determinant for postural parameters during sensorial conflict compared to age, gender, body mass index and past PA. Regular PA, even when started late in life, allows appropriate reorganization of the different components of postural control during sensory conflicting situations. Indeed, active subjects were more able to compensate for suppressed or perturbed sensory information by an increased usage of another referential and so to correct their posture by adopting a more appropriate balance strategy. Thus, PA counteracts the age-related decline of postural control and could consequently reduce the risk of falling.

  9. Re-Mediating Current Activity for the Future

    Science.gov (United States)

    Gutierrez, Kris D.

    2012-01-01

    The growing poverty and inequity in America should create a sense of urgency in researchers to leverage what they know for the public good--to intervene more productively and vigorously in an ever more fragile public educational system and to address the increasing vulnerability of far too many youth in the United States. The current worldwide…

  10. When abuse primes addiction - automatic activation of alcohol concepts by child maltreatment related cues in emotionally abused alcoholics.

    Science.gov (United States)

    Potthast, Nadine; Neuner, Frank; Catani, Claudia

    2015-09-01

    Recent research indicates that there is a link between emotional maltreatment and alcohol dependence (AD), but the underlying mechanisms still need to be clarified. There is reason to assume that maltreatment related cues automatically activate an associative memory network comprising cues eliciting craving as well as alcohol-related responses. The current study aimed to examine this network in AD patients who experienced emotional abuse using a priming paradigm. A specific priming effect in emotionally abused AD subjects was hypothesized for maltreatment related words that preceded alcohol related words. 49 AD subjects (n=14 with emotional abuse vs. n=35 without emotional abuse) and 34 control subjects performed a priming task with maltreatment related and neutral prime words combined with alcohol related and neutral target words. Maltreatment related words consisted of socially and physically threatening words. As hypothesized, a specific priming effect for socially threatening and physically threatening cues was found only in AD subjects with emotional abuse. The present data are the first to provide evidence that child maltreatment related cues automatically activate an associative memory network in alcoholics with emotional abuse experiences. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Currently used pesticides and their mixtures affect the function of sex hormone receptors and aromatase enzyme activity

    Energy Technology Data Exchange (ETDEWEB)

    Kjeldsen, Lisbeth Stigaard; Ghisari, Mandana; Bonefeld-Jørgensen, Eva Cecilie, E-mail: ebj@mil.au.dk

    2013-10-15

    The endocrine-disrupting potential of pesticides is of health concern, since they are found ubiquitously in the environment and in food items. We investigated in vitro effects on estrogen receptor (ER) and androgen receptor (AR) transactivity, and aromatase enzyme activity, of the following pesticides: 2-methyl-4-chlorophenoxyacetic acid (MCPA), terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb, cypermethrin, tau fluvalinate, malathion and the metabolite ethylene thiourea (ETU). The pesticides were analyzed alone and in selected mixtures. Effects of the pesticides on ER and AR function were assessed in human breast carcinoma MVLN cells and hamster ovary CHO-K1 cells, respectively, using luciferase reporter gene assays. Effects on aromatase enzyme activity were analyzed in human choriocarcinoma JEG-3 cells, employing the classical [{sup 3}H]{sub 2}O method. Five pesticides (terbuthylazine, propiconazole, prothioconazole, cypermethrin and malathion) weakly induced the ER transactivity, and three pesticides (bitertanol, propiconazole and mancozeb) antagonized the AR activity in a concentration-dependent manner. Three pesticides (terbuthylazine, propiconazole and prothioconazole) weakly induced the aromatase activity. In addition, two mixtures, consisting of three pesticides (bitertanol, propiconazole, cypermethrin) and five pesticides (terbuthylazine, bitertanol, propiconazole, cypermethrin, malathion), respectively, induced the ER transactivity and aromatase activity, and additively antagonized the AR transactivity. In conclusion, our data suggest that currently used pesticides possess endocrine-disrupting potential in vitro which can be mediated via ER, AR and aromatase activities. The observed mixture effects emphasize the importance of considering the combined action of pesticides in order to assure proper estimations of related health effect risks

  12. Biorefineries: Current activities and future developments

    International Nuclear Information System (INIS)

    Demirbas, Ayhan

    2009-01-01

    This paper reviews the current refuel valorization facilities as well as the future importance of biorefineries. A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power, and chemicals from biomass. Biorefineries combine the necessary technologies of the biorenewable raw materials with those of chemical intermediates and final products. Char production by pyrolysis, bio-oil production by pyrolysis, gaseous fuels from biomass, Fischer-Tropsch liquids from biomass, hydrothermal liquefaction of biomass, supercritical liquefaction, and biochemical processes of biomass are studied and concluded in this review. Upgraded bio-oil from biomass pyrolysis can be used in vehicle engines as fuel.

  13. Biorefineries: Current activities and future developments

    Energy Technology Data Exchange (ETDEWEB)

    Demirbas, Ayhan [Sila Science, Trabzon (Turkey)

    2009-11-15

    This paper reviews the current refuel valorization facilities as well as the future importance of biorefineries. A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power, and chemicals from biomass. Biorefineries combine the necessary technologies of the biorenewable raw materials with those of chemical intermediates and final products. Char production by pyrolysis, bio-oil production by pyrolysis, gaseous fuels from biomass, Fischer-Tropsch liquids from biomass, hydrothermal liquefaction of biomass, supercritical liquefaction, and biochemical processes of biomass are studied and concluded in this review. Upgraded bio-oil from biomass pyrolysis can be used in vehicle engines as fuel. (author)

  14. Effects of antagonists and heat on TRPM8 channel currents in dorsal root ganglion neuron activated by nociceptive cold stress and menthol.

    Science.gov (United States)

    Naziroğlu, Mustafa; Ozgül, Cemil

    2012-02-01

    Transient receptor potential ion channel melastatin subtype 8 (TRPM8) is activated by cold temperature and cooling agents, such as menthol and icilin. Compounds containing peppermint are reported to reduce symptoms of environmental cold stress such as cold allodynia in dorsal root ganglion (DRG) neuron; however, the underlying mechanisms of action are unclear. We tested the effects of physiological heat (37°C), anthralic acid (ACA and 0.025 mM), 2-aminoethyl diphenylborinate (2-APB and 0.05) on noxious cold (10°C) and menthol (0.1 mM)-induced TRPM8 cation channel currents in the DRG neurons of rats. DRG neurons were freshly isolated from rats. In whole-cell patch clamp experiments, TRPM8 currents were consistently induced by noxious cold or menthol. TRPM8 channels current densities of the neurons were higher in cold and menthol groups than in control. When the physiological heat is introduced by chamber TRPM8 channel currents were inhibited by the heat. Noxious cold-induced Ca(2+) gates were blocked by the ACA although menthol-induced TRPM8 currents were not blocked by ACA and 2-APB. In conclusion, the results suggested that activation of TRPM8 either by menthol or nociceptive cold can activate TRPM8 channels although we observed the protective role of heat, ACA and 2-APB through a TRPM8 channel in nociceptive cold-activated DRG neurons. Since cold allodynia is a common feature of neuropathic pain and diseases of sensory neuron, our findings are relevant to the etiology of neuropathology in DRG neurons.

  15. The Hydrological Open Air Laboratory (HOAL) in Petzenkirchen: a hypotheses driven observatory

    Science.gov (United States)

    Blöschl, G.; Blaschke, A. P.; Broer, M.; Bucher, C.; Carr, G.; Chen, X.; Eder, A.; Exner-Kittridge, M.; Farnleitner, A.; Flores-Orozco, A.; Haas, P.; Hogan, P.; Kazemi Amiri, A.; Oismüller, M.; Parajka, J.; Silasari, R.; Stadler, P.; Strauß, P.; Vreugdenhil, M.; Wagner, W.; Zessner, M.

    2015-07-01

    Hydrological observatories bear a lot of resemblance to the more traditional research catchment concept but tend to differ in providing more long term facilities that transcend the lifetime of individual projects, are more strongly geared towards performing interdisciplinary research, and are often designed as networks to assist in performing collaborative science. This paper illustrates how the experimental and monitoring setup of an observatory, the 66 ha Hydrological Open Air Laboratory (HOAL) in Petzenkirchen, Lower Austria, has been established in a way that allows meaningful hypothesis testing. The overarching science questions guided site selection, identifying dissertation topics and the base monitoring. The specific hypotheses guided the dedicated monitoring and sampling, individual experiments, and repeated experiments with controlled boundary conditions. The purpose of the HOAL is to advance the understanding of water related flow and transport processes involving sediments, nutrients and microbes in small catchments. The HOAL catchment is ideally suited for this purpose, because it features a range of different runoff generation processes (surface runoff, springs, tile drains, wetlands), the nutrient inputs are known, and it is convenient from a logistic point of view as all instruments can be connected to the power grid and a high speed glassfibre Local Area Network. The multitude of runoff generation mechanisms in the catchment provide a genuine laboratory where hypotheses of flow and transport can be tested, either by controlled experiments or by contrasting sub-regions of different characteristics. This diversity also ensures that the HOAL is representative of a range of catchments around the world and the specific process findings from the HOAL are applicable to a variety of agricultural catchment settings. The HOAL is operated jointly by the Vienna University of Technology and the Federal Agency for Water Management and takes advantage of the

  16. A cluster-randomized controlled trial of strategies to increase adolescents' physical activity and motivation during physical education lessons: the Motivating Active Learning in Physical Education (MALP) trial.

    Science.gov (United States)

    Rosenkranz, Richard R; Lubans, David R; Peralta, Louisa R; Bennie, Andrew; Sanders, Taren; Lonsdale, Chris

    2012-10-01

    The physical activity (PA) levels of many children and adolescents in Australia are currently insufficient to promote health benefits. Physical education (PE) programs aim to promote PA and reach nearly all school-aged children, but PA levels within PE lessons are often low. PE teachers may influence children's motivation to be physically active in PE lessons, but little is known about teacher strategies that effectively motivate children to participate in PA, and few intervention studies have examined motivational strategies in PE. The purpose of this study was to compare the effect of three motivational strategies, each based on Self-Determination Theory (SDT), on PA levels, and their hypothesized antecedents, during year 8 PE lessons. This study employed a cluster-randomized controlled trial design. Following a familiarization session, PA levels and hypothesized PA antecedents were measured during a baseline lesson and a post-intervention or control lesson. Teachers (n = 16) and their classes from five secondary schools in Sydney, Australia were randomly assigned into four blocks and instructed to provide one of four 20-min lesson teaching strategy conditions: (1) explaining the relevance of activities; (2) providing choice from PA options selected by the teacher; (3) providing equipment and free choice of activities; or (4) usual practice. The primary outcomes were lesson time spent in moderate-to-vigorous PA, and motivation towards the lesson. Secondary outcomes were perceptions of teacher behavior, psychological needs satisfaction, and lesson time spent in sedentary behavior. PA and sedentary behavior were measured during baseline and post-intervention lessons with waist-mounted Actigraph GT3X accelerometers. Teacher behavior, psychological needs satisfaction, and motivation were assessed via questionnaires at the end of each lesson. Linear mixed-model analyses will be run on all outcomes, with students nested within teachers as a random effect. Study

  17. A cluster-randomized controlled trial of strategies to increase adolescents’ physical activity and motivation during physical education lessons: the Motivating Active Learning in Physical Education (MALP trial

    Directory of Open Access Journals (Sweden)

    Rosenkranz Richard R

    2012-10-01

    Full Text Available Abstract Background The physical activity (PA levels of many children and adolescents in Australia are currently insufficient to promote health benefits. Physical education (PE programs aim to promote PA and reach nearly all school-aged children, but PA levels within PE lessons are often low. PE teachers may influence children’s motivation to be physically active in PE lessons, but little is known about teacher strategies that effectively motivate children to participate in PA, and few intervention studies have examined motivational strategies in PE. The purpose of this study was to compare the effect of three motivational strategies, each based on Self-Determination Theory (SDT, on PA levels, and their hypothesized antecedents, during year 8 PE lessons. Methods/design This study employed a cluster-randomized controlled trial design. Following a familiarization session, PA levels and hypothesized PA antecedents were measured during a baseline lesson and a post-intervention or control lesson. Teachers (n = 16 and their classes from five secondary schools in Sydney, Australia were randomly assigned into four blocks and instructed to provide one of four 20-min lesson teaching strategy conditions: (1 explaining the relevance of activities; (2 providing choice from PA options selected by the teacher; (3 providing equipment and free choice of activities; or (4 usual practice. The primary outcomes were lesson time spent in moderate-to-vigorous PA, and motivation towards the lesson. Secondary outcomes were perceptions of teacher behavior, psychological needs satisfaction, and lesson time spent in sedentary behavior. PA and sedentary behavior were measured during baseline and post-intervention lessons with waist-mounted Actigraph GT3X accelerometers. Teacher behavior, psychological needs satisfaction, and motivation were assessed via questionnaires at the end of each lesson. Linear mixed-model analyses will be run on all outcomes, with students nested

  18. The activity of spontaneous action potentials in developing hair cells is regulated by Ca(2+-dependence of a transient K+ current.

    Directory of Open Access Journals (Sweden)

    Snezana Levic

    Full Text Available Spontaneous action potentials have been described in developing sensory systems. These rhythmic activities may have instructional roles for the functional development of synaptic connections. The importance of spontaneous action potentials in the developing auditory system is underpinned by the stark correlation between the time of auditory system functional maturity, and the cessation of spontaneous action potentials. A prominent K(+ current that regulates patterning of action potentials is I(A. This current undergoes marked changes in expression during chicken hair cell development. Although the properties of I(A are not normally classified as Ca(2+-dependent, we demonstrate that throughout the development of chicken hair cells, I(A is greatly reduced by acute alterations of intracellular Ca(2+. As determinants of spike timing and firing frequency, intracellular Ca(2+ buffers shift the activation and inactivation properties of the current to more positive potentials. Our findings provide evidence to demonstrate that the kinetics and functional expression of I(A are tightly regulated by intracellular Ca(2+. Such feedback mechanism between the functional expression of I(A and intracellular Ca(2+ may shape the activity of spontaneous action potentials, thus potentially sculpting synaptic connections in an activity-dependent manner in the developing cochlea.

  19. Antiarrhythmic properties of a rapid delayed-rectifier current activator in rabbit models of acquired long QT syndrome

    DEFF Research Database (Denmark)

    Diness, Thomas G; Yeh, Yung-Hsin; Qi, Xiao Yan

    2008-01-01

    effect of a novel compound (NS1643) that activates the rapid delayed-rectifier K+ current, I(Kr), in two rabbit models of acquired LQTS. METHODS AND RESULTS: We used two clinically relevant in vivo rabbit models of TdP in which we infused NS1643 or vehicle: (i) three-week atrioventricular block...

  20. LANSCE beam current limiter

    International Nuclear Information System (INIS)

    Gallegos, F.R.

    1996-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described

  1. Current Western Reactions to Mass Surveillance

    DEFF Research Database (Denmark)

    Nickel, Sandro

    2015-01-01

    hypotheses regarding the question why a movement has not been formed. The chapter produces support for the hypotheses that a lack of anger, a lack of hope for change, the ab-stractness of the issue, a lack of a common antagonist and a perceived shrinking importance of privacy are influential variables...

  2. Visual functions in phenylketonuria-evaluating the dopamine and long-chain polyunsaturated fatty acids depletion hypotheses.

    Science.gov (United States)

    Gramer, Gwendolyn; Förl, Birgit; Springer, Christina; Weimer, Petra; Haege, Gisela; Mackensen, Friederike; Müller, Edith; Völcker, Hans Eberhard; Hoffmann, Georg Friedrich; Lindner, Martin; Krastel, Hermann; Burgard, Peter

    2013-01-01

    In phenylketonuria presymptomatic treatment following newborn screening prevents severe mental and physical impairment. The reasons for subtle impairments of cerebral functions despite early treatment remain unclear. We assessed a broad spectrum of visual functions in early-treated patients with phenylketonuria and evaluated two hypotheses-the dopamine and the long-chain polyunsaturated fatty acids (LCPUFAs) depletion hypotheses. Contrast sensitivity, colour vision, electroretinography, frequency doubling technology campimetry (FDT), and their relation with blood phenylalanine and docosahexaenoic acid levels were assessed in 36 patients with phenylketonuria and 18 age-matched healthy controls. Contrast sensitivity was significantly lower and total error scores in colour vision significantly higher in patients than controls. Electroretinography results differed significantly between patients and controls. We found a trend for the effect of phenylalanine-levels on contrast sensitivity and a significant effect on colour vision/FDT results. Docosahexaenoic acid levels in erythrocytes were not associated with visual functions. This is the first evaluation of visual functions in phenylketonuria using a comprehensive ophthalmological test battery. We found no evidence supporting the long-chain polyunsaturated fatty acids depletion hypothesis. However, the effect of phenylalanine-levels on visual functions suggests that imbalance between phenylalanine and tyrosine may affect retinal dopamine levels in phenylketonuria. This is supported by the similar patterns of visual functions in patients with phenylketonuria observed in our study and patients with Parkinson's disease. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Confidence Intervals: From tests of statistical significance to confidence intervals, range hypotheses and substantial effects

    Directory of Open Access Journals (Sweden)

    Dominic Beaulieu-Prévost

    2006-03-01

    Full Text Available For the last 50 years of research in quantitative social sciences, the empirical evaluation of scientific hypotheses has been based on the rejection or not of the null hypothesis. However, more than 300 articles demonstrated that this method was problematic. In summary, null hypothesis testing (NHT is unfalsifiable, its results depend directly on sample size and the null hypothesis is both improbable and not plausible. Consequently, alternatives to NHT such as confidence intervals (CI and measures of effect size are starting to be used in scientific publications. The purpose of this article is, first, to provide the conceptual tools necessary to implement an approach based on confidence intervals, and second, to briefly demonstrate why such an approach is an interesting alternative to an approach based on NHT. As demonstrated in the article, the proposed CI approach avoids most problems related to a NHT approach and can often improve the scientific and contextual relevance of the statistical interpretations by testing range hypotheses instead of a point hypothesis and by defining the minimal value of a substantial effect. The main advantage of such a CI approach is that it replaces the notion of statistical power by an easily interpretable three-value logic (probable presence of a substantial effect, probable absence of a substantial effect and probabilistic undetermination. The demonstration includes a complete example.

  4. Understanding the current state of infection preventionists through competency, role, and activity self-assessment.

    Science.gov (United States)

    Kalp, Ericka L; Marx, James F; Davis, James

    2017-06-01

    The Association for Professionals in Infection Control and Epidemiology (APIC) MegaSurvey, administered in 2015, was completed by approximately 4,079 APIC members. The survey sought to gain a better understanding the current state of 4 components of infection prevention practice: demographic characteristics, compensation, organizational structure, and practice and competency. The data for this analysis come from the APIC MegaSurvey Practice and Competency domain. Descriptive statistics and χ 2 analyses were conducted to examine differences in infection preventionist (IP) competency, roles, and activity self-assessments. The majority of IPs self-assessed their competency as Proficient compared with Novice or Expert for each of the 8 IP core competency activities. Forty percent of IPs self-rated their competency as Expert in the Preventing/Controlling the Transmission of Infectious Agents/HAIs component. IPs reported Novice competency in Employee/Occupational Health (29%); Cleaning, Sterilization, Disinfection, and Asepsis (23%); and Education and Research categories (22%). Differences in self-rated competency among IPs by discipline type (public health, nurse, and laboratory) were identified. Differences in self-rated competency were identified for each of the 8 IP core competency activities. IPs report using various resource types to gain competency. Future research is needed to identify opportunities to increase competency levels in the weakest-rated competency activities. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  5. Properties of hypothesis testing techniques and (Bayesian) model selection for exploration-based and theory-based (order-restricted) hypotheses

    NARCIS (Netherlands)

    Kuiper, Rebecca M.; Nederhoff, Tim; Klugkist, Irene

    2015-01-01

    In this paper, the performance of six types of techniques for comparisons of means is examined. These six emerge from the distinction between the method employed (hypothesis testing, model selection using information criteria, or Bayesian model selection) and the set of hypotheses that is

  6. Nearly Complete 28S rRNA Gene Sequences Confirm New Hypotheses of Sponge Evolution

    Science.gov (United States)

    Thacker, Robert W.; Hill, April L.; Hill, Malcolm S.; Redmond, Niamh E.; Collins, Allen G.; Morrow, Christine C.; Spicer, Lori; Carmack, Cheryl A.; Zappe, Megan E.; Pohlmann, Deborah; Hall, Chelsea; Diaz, Maria C.; Bangalore, Purushotham V.

    2013-01-01

    The highly collaborative research sponsored by the NSF-funded Assembling the Porifera Tree of Life (PorToL) project is providing insights into some of the most difficult questions in metazoan systematics. Our understanding of phylogenetic relationships within the phylum Porifera has changed considerably with increased taxon sampling and data from additional molecular markers. PorToL researchers have falsified earlier phylogenetic hypotheses, discovered novel phylogenetic alliances, found phylogenetic homes for enigmatic taxa, and provided a more precise understanding of the evolution of skeletal features, secondary metabolites, body organization, and symbioses. Some of these exciting new discoveries are shared in the papers that form this issue of Integrative and Comparative Biology. Our analyses of over 300 nearly complete 28S ribosomal subunit gene sequences provide specific case studies that illustrate how our dataset confirms new hypotheses of sponge evolution. We recovered monophyletic clades for all 4 classes of sponges, as well as the 4 major clades of Demospongiae (Keratosa, Myxospongiae, Haploscleromorpha, and Heteroscleromorpha), but our phylogeny differs in several aspects from traditional classifications. In most major clades of sponges, families within orders appear to be paraphyletic. Although additional sampling of genes and taxa are needed to establish whether this pattern results from a lack of phylogenetic resolution or from a paraphyletic classification system, many of our results are congruent with those obtained from 18S ribosomal subunit gene sequences and complete mitochondrial genomes. These data provide further support for a revision of the traditional classification of sponges. PMID:23748742

  7. Mu-opioid receptor knockout mice show diminished food-anticipatory activity

    NARCIS (Netherlands)

    Kas, Martien J H; van den Bos, Ruud; Baars, Annemarie M; Lubbers, Marianne; Lesscher, Heidi M B; Hillebrand, Jacquelien J G; Schuller, Alwin G; Pintar, John E; Spruijt, Berry M

    We have previously suggested that during or prior to activation of anticipatory behaviour to a coming reward, mu-opioid receptors are activated. To test this hypothesis schedule induced food-anticipatory activity in mu-opioid receptor knockout mice was measured using running wheels. We hypothesized

  8. Are the physical activity parenting practices reported by U.S. and Canadian parents captured in currently published instruments?

    Science.gov (United States)

    The purpose of this study was to compare the physical activity parenting practices (PAPPs) parents report using with the PAPPs incorporated in the published literature. PAPPs in the literature were identified by reviewing the content of 74 published PAPPs measures obtained from current systematic re...

  9. Relationships between the Birkeland currents, ionospheric currents, and electric fields

    International Nuclear Information System (INIS)

    Bleuler, E.; Li, C.H.; Nisbet, J.S.

    1982-01-01

    Calculations are made of the currents and electric fields in the ionosphere by using a global model of the electron densities including conjugate coupling along field lines. Incoherent scatter and rocket measurements of high-latitude electron densities have been used to derive realistic variations of the polar conductivities as a function of magnetic activity. The Birkeland currents have been specified in terms of three indices, the total current into and out of the hemisphere, the ratio of the magnitudes of the currents in the AM and PM sectors, R/sub ap/ , and R 12 , the ratio of the magnitudes of the currents in region 1 and 2. The relationship between these parameters of the Birkeland current systems and the auroral electrojet indices AE, AL, and AU is examined as well as the polar cap potential and the electric field at lower latitudes. The cusp currents have been modeled in relation to the interplanetary magnetic field and calculations are given of their effect on electric field and current patterns. One aim of this study is to produce a mathematical model of the currents, electric fields and energy inputs produced by field aligned currents that is consistent with, and specifiable in terms of, measured geophysical indices

  10. Quantitative critical thinking: Student activities using Bayesian updating

    Science.gov (United States)

    Warren, Aaron R.

    2018-05-01

    One of the central roles of physics education is the development of students' ability to evaluate proposed hypotheses and models. This ability is important not just for students' understanding of physics but also to prepare students for future learning beyond physics. In particular, it is often hoped that students will better understand the manner in which physicists leverage the availability of prior knowledge to guide and constrain the construction of new knowledge. Here, we discuss how the use of Bayes' Theorem to update the estimated likelihood of hypotheses and models can help achieve these educational goals through its integration with evaluative activities that use hypothetico-deductive reasoning. Several types of classroom and laboratory activities are presented that engage students in the practice of Bayesian likelihood updating on the basis of either consistency with experimental data or consistency with pre-established principles and models. This approach is sufficiently simple for introductory physics students while offering a robust mechanism to guide relatively sophisticated student reflection concerning models, hypotheses, and problem-solutions. A quasi-experimental study utilizing algebra-based introductory courses is presented to assess the impact of these activities on student epistemological development. The results indicate gains on the Epistemological Beliefs Assessment for Physical Science (EBAPS) at a minimal cost of class-time.

  11. [Current animal feeds with antimicrobial activity].

    Science.gov (United States)

    Drumev, D

    1981-01-01

    Among the growth-promoting substances and factors contributing to fodder utilization in growing farm animals, also called nutritive, ergotropic means, the antibiotics and some synthetic chemotherapeutics have acquired special importance. To avoid the hazardous effect in humans consuming products of animal origin there should be no residual amounts of these stimulating agents in such products. That is why it has been assumed in a number of countries to use for the same purpose only nutritive means that are not applied as therapeutic agents. Such means should neither induce resistence to antibiotics and chemotherapeutics in microorganism nor should they be resorbed by the alimentary tract (or resorption should be negligible) or they are rapidly eliminated from the animal body, leaving no residual amounts. They should likewise act chiefly against gram-positive organisms, inducing no allergic reactions in the animals. Described are the following nutritive antibiotics: flavophospholipol (bambermycin, menomycin--flavomycin, producing a nutritive effect also in ruminants with a developed forestomach, and rebuilds sensitivity in antibiotic-resistant organisms belonging to Enterobacteriaceae), avoparcin (avotan--also active in ruminants with a developed forestomach), virginiamycin (staphylomycin--escalin, stafac), zincbacitracin (bacipharmin, baciferm), grisin (kormogrisin, of a road spectrum, with an antimycotic effect, raising the fertilization rate and activating phagocitosis), vitamycin-A (vitamycin--active also at retinol deficiency, lambdamycin, nosiheptide (primofax), efrotomycin. Due consideration is given to such chemotherapeutics as nitrovin (payson, paison), carbadox (mecadox, fortigro, of a broad spectrum retained for a longer period in the body of pigs), olaquindox (bio-N-celbar--of a broad spectrum, particularly with regard to gram-negative organisms, applied at present as a therapeutic and prophylactic preparation), cyadox (with a broad sprectrum). The

  12. On the role of neutral flow in field-aligned currents

    Science.gov (United States)

    Mannucci, Anthony J.; Verkhoglyadova, Olga P.; Meng, Xing; McGranaghan, Ryan

    2018-01-01

    In this brief note we explore the role of the neutral atmosphere in magnetosphere-ionosphere coupling. We analyze momentum balance in the ion rest frame to form hypotheses regarding the role of neutral momentum in the lower ionosphere during geomagnetic storms. Neutral momentum that appears in the ion rest frame is likely the result of momentum imparted to ionospheric ions by solar wind flow and the resultant magnetospheric dynamics. The resulting ion-neutral collisions lead to the existence of an electric field. Horizontal electron flow balances the momentum supplied by this electric field. We suggest a possible role played by the neutral atmosphere in generating field-aligned currents due to local auroral heating. Our physical interpretation suggests that thermospheric neutral dynamics plays a complementary role to the high-latitude field-aligned currents and electric fields resulting from magnetospheric dynamics.

  13. The Acute Relationships Between Affect, Physical Feeling States, and Physical Activity in Daily Life: A Review of Current Evidence

    OpenAIRE

    Liao, Yue; Shonkoff, Eleanor T.; Dunton, Genevieve F.

    2015-01-01

    Until recently, most studies investigating the acute relationships between affective and physical feeling states and physical activity were conducted in controlled laboratory settings, whose results might not translate well to everyday life. This review was among the first attempts to synthesize current evidence on the acute (e.g., within a few hours) relationships between affective and physical feeling states and physical activity from studies conducted in free-living, naturalistic settings ...

  14. Prolonged Intracellular Na+ Dynamics Govern Electrical Activity in Accessory Olfactory Bulb Mitral Cells.

    Directory of Open Access Journals (Sweden)

    Asaph Zylbertal

    2015-12-01

    Full Text Available Persistent activity has been reported in many brain areas and is hypothesized to mediate working memory and emotional brain states and to rely upon network or biophysical feedback. Here, we demonstrate a novel mechanism by which persistent neuronal activity can be generated without feedback, relying instead on the slow removal of Na+ from neurons following bursts of activity. We show that mitral cells in the accessory olfactory bulb (AOB, which plays a major role in mammalian social behavior, may respond to a brief sensory stimulation with persistent firing. By combining electrical recordings, Ca2+ and Na+ imaging, and realistic computational modeling, we explored the mechanisms underlying the persistent activity in AOB mitral cells. We found that the exceptionally slow inward current that underlies this activity is governed by prolonged dynamics of intracellular Na+ ([Na+]i, which affects neuronal electrical activity via several pathways. Specifically, elevated dendritic [Na+]i reverses the Na+-Ca2+ exchanger activity, thus modifying the [Ca2+]i set-point. This process, which relies on ubiquitous membrane mechanisms, is likely to play a role in other neuronal types in various brain regions.

  15. Comments and hypotheses on the mechanism of methane against ischemia/reperfusion injury

    Directory of Open Access Journals (Sweden)

    He Li

    2017-01-01

    Full Text Available As we all know, methane is a kind of fuel. Previous studies have shown that methanogens in the colon can react with carbon dioxide and hydrogen to produce methane. In a recent study, the anti-inflammatory effects of methane were shown in a dog model of small intestinal ischemia/reperfusion. The mechanism of this anti-inflammatory effect needs further investigation. Recently, studies have shown anti-inflammatory, anti-apoptotic and anti-oxidative effects of methane on different organic injuries. According to the results of these studies, we hypothesize that the initial effects of methane are to react with free radicals and enhance expression of antioxidase through forkhead box transcription factor class O pathway. The anti-inflammatory effect is following the anti-oxidative effect, and the anti-apoptotic effect relies on anti-inflammatory and anti-oxidative effects.

  16. Consider the Alternative: The Effects of Causal Knowledge on Representing and Using Alternative Hypotheses in Judgments under Uncertainty

    Science.gov (United States)

    Hayes, Brett K.; Hawkins, Guy E.; Newell, Ben R.

    2016-01-01

    Four experiments examined the locus of impact of causal knowledge on consideration of alternative hypotheses in judgments under uncertainty. Two possible loci were examined; overcoming neglect of the alternative when developing a representation of a judgment problem and improving utilization of statistics associated with the alternative…

  17. COVAR: Computer Program for Multifactor Relative Risks and Tests of Hypotheses Using a Variance-Covariance Matrix from Linear and Log-Linear Regression

    Directory of Open Access Journals (Sweden)

    Leif E. Peterson

    1997-11-01

    Full Text Available A computer program for multifactor relative risks, confidence limits, and tests of hypotheses using regression coefficients and a variance-covariance matrix obtained from a previous additive or multiplicative regression analysis is described in detail. Data used by the program can be stored and input from an external disk-file or entered via the keyboard. The output contains a list of the input data, point estimates of single or joint effects, confidence intervals and tests of hypotheses based on a minimum modified chi-square statistic. Availability of the program is also discussed.

  18. Current activities and future trends in reliability analysis and probabilistic safety assessment in Hungary

    International Nuclear Information System (INIS)

    Hollo, E.; Toth, J.

    1986-01-01

    In Hungary reliability analysis (RA) and probabilistic safety assessment (PSA) of nuclear power plants was initiated 3 years ago. First, computer codes for automatic fault tree analysis (CAT, PREP) and numerical evaluation (REMO, KITT1,2) were adapted. Two main case studies - detailed availability/reliability calculation of diesel sets and analysis of safety systems influencing event sequences induced by large LOCA - were performed. Input failure data were taken from publications, a need for failure and reliability data bank was revealed. Current and future activities involves: setup of national data bank for WWER-440 units; full-scope level-I PSA of PAKS NPP in Hungary; operational safety assessment of particular problems at PAKS NPP. In the present article the state of RA and PSA activities in Hungary, as well as the main objectives of ongoing work are described. A need for international cooperation (for unified data collection of WWER-440 units) and for IAEA support (within Interregional Program INT/9/063) is emphasized. (author)

  19. The Rhodes Scholarship in the Current Era of Student Activism: What Do We Consider "Prestigious" and Who Benefits?

    Science.gov (United States)

    Adam, LeAnn

    2016-01-01

    Contemporary student activism has revealed deep feelings of alienation on college campuses, prompting strong reactions to current and historical racial injustice, including the history of Cecil Rhodes. Can advisors promote restorative justice by encouraging reflection upon privileges afforded to Rhodes scholars and their responsibility to address…

  20. Blockade of persistent sodium currents contributes to the riluzole-induced inhibition of spontaneous activity and oscillations in injured DRG neurons.

    Directory of Open Access Journals (Sweden)

    Rou-Gang Xie

    Full Text Available In addition to a fast activating and immediately inactivating inward sodium current, many types of excitable cells possess a noninactivating or slowly inactivating component: the persistent sodium current (I(NaP. The I(NaP is found in normal primary sensory neurons where it is mediated by tetrodotoxin-sensitive sodium channels. The dorsal root ganglion (DRG is the gateway for ectopic impulses that originate in pathological pain signals from the periphery. However, the role of I(NaP in DRG neurons remains unclear, particularly in neuropathic pain states. Using in vivo recordings from single medium- and large-diameter fibers isolated from the compressed DRG in Sprague-Dawley rats, we show that local application of riluzole, which blocks the I(NaP, also inhibits the spontaneous activity of A-type DRG neurons in a dose-dependent manner. Significantly, riluzole also abolished subthreshold membrane potential oscillations (SMPOs, although DRG neurons still responded to intracellular current injection with a single full-sized spike. In addition, the I(NaP was enhanced in medium- and large-sized neurons of the compressed DRG, while bath-applied riluzole significantly inhibited the I(NaP without affecting the transient sodium current (I(NaT. Taken together, these results demonstrate for the first time that the I(NaP blocker riluzole selectively inhibits I(NaP and thereby blocks SMPOs and the ectopic spontaneous activity of injured A-type DRG neurons. This suggests that the I(NaP of DRG neurons is a potential target for treating neuropathic pain at the peripheral level.

  1. Blockade of persistent sodium currents contributes to the riluzole-induced inhibition of spontaneous activity and oscillations in injured DRG neurons.

    Science.gov (United States)

    Xie, Rou-Gang; Zheng, Da-Wei; Xing, Jun-Ling; Zhang, Xu-Jie; Song, Ying; Xie, Ya-Bin; Kuang, Fang; Dong, Hui; You, Si-Wei; Xu, Hui; Hu, San-Jue

    2011-04-25

    In addition to a fast activating and immediately inactivating inward sodium current, many types of excitable cells possess a noninactivating or slowly inactivating component: the persistent sodium current (I(NaP)). The I(NaP) is found in normal primary sensory neurons where it is mediated by tetrodotoxin-sensitive sodium channels. The dorsal root ganglion (DRG) is the gateway for ectopic impulses that originate in pathological pain signals from the periphery. However, the role of I(NaP) in DRG neurons remains unclear, particularly in neuropathic pain states. Using in vivo recordings from single medium- and large-diameter fibers isolated from the compressed DRG in Sprague-Dawley rats, we show that local application of riluzole, which blocks the I(NaP), also inhibits the spontaneous activity of A-type DRG neurons in a dose-dependent manner. Significantly, riluzole also abolished subthreshold membrane potential oscillations (SMPOs), although DRG neurons still responded to intracellular current injection with a single full-sized spike. In addition, the I(NaP) was enhanced in medium- and large-sized neurons of the compressed DRG, while bath-applied riluzole significantly inhibited the I(NaP) without affecting the transient sodium current (I(NaT)). Taken together, these results demonstrate for the first time that the I(NaP) blocker riluzole selectively inhibits I(NaP) and thereby blocks SMPOs and the ectopic spontaneous activity of injured A-type DRG neurons. This suggests that the I(NaP) of DRG neurons is a potential target for treating neuropathic pain at the peripheral level.

  2. Current and novel therapeutic molecules and targets in Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Ashwini Kumar

    2016-01-01

    Full Text Available Alzheimer's disease (AD is a neurodegenerative disorder in which the death of brain cells causes memory loss and cognitive decline, i.e., dementia. The disease starts with mild symptoms and gradually becomes severe. AD is one of the leading causes of mortality worldwide. Several different hallmarks of the disease have been reported such as deposits of β-amyloid around neurons, hyperphosphorylated tau protein, oxidative stress, dyshomeostasis of bio-metals, low levels of acetylcholine, etc. AD is not simple to diagnose since there is no single diagnostic test for it. Pharmacotherapy for AD currently provides only symptomatic relief and mostly targets cognitive revival. Computational biology approaches have proved to be reliable tools for the selection of novel targets and therapeutic ligands. Molecular docking is a key tool in computer-assisted drug design and development. Docking has been utilized to perform virtual screening on large libraries of compounds, and propose structural hypotheses of how the ligands bind with the target with lead optimization. Another potential application of docking is optimization stages of the drug-discovery cycle. This review summarizes the known drug targets of AD, in vivo active agents against AD, state-of-the-art docking studies done in AD, and future prospects of the docking with particular emphasis on AD.

  3. Dopamine D4 receptor activation increases hippocampal gamma oscillations by enhancing synchronization of fast-spiking interneurons.

    Directory of Open Access Journals (Sweden)

    Richard Andersson

    Full Text Available BACKGROUND: Gamma oscillations are electric activity patterns of the mammalian brain hypothesized to serve attention, sensory perception, working memory and memory encoding. They are disrupted or altered in schizophrenic patients with associated cognitive deficits, which persist in spite of treatment with antipsychotics. Because cognitive symptoms are a core feature of schizophrenia it is relevant to explore signaling pathways that potentially regulate gamma oscillations. Dopamine has been reported to decrease gamma oscillation power via D1-like receptors. Based on the expression pattern of D4 receptors (D4R in hippocampus, and pharmacological effects of D4R ligands in animals, we hypothesize that they are in a position to regulate gamma oscillations as well. METHODOLOGY/PRINCIPAL FINDINGS: To address this hypothesis we use rat hippocampal slices and kainate-induced gamma oscillations. Local field potential recordings as well as intracellular recordings of pyramidal cells, fast-spiking and non-fast-spiking interneurons were carried out. We show that D4R activation with the selective ligand PD168077 increases gamma oscillation power, which can be blocked by the D4R-specific antagonist L745,870 as well as by the antipsychotic drug Clozapine. Pyramidal cells did not exhibit changes in excitatory or inhibitory synaptic current amplitudes, but inhibitory currents became more coherent with the oscillations after application of PD168077. Fast-spiking, but not non-fast spiking, interneurons, increase their action potential phase-coupling and coherence with regard to ongoing gamma oscillations in response to D4R activation. Among several possible mechanisms we found that the NMDA receptor antagonist AP5 also blocks the D4R mediated increase in gamma oscillation power. CONCLUSIONS/SIGNIFICANCE: We conclude that D4R activation affects fast-spiking interneuron synchronization and thereby increases gamma power by an NMDA receptor-dependent mechanism. This

  4. Protein kinase C epsilon mediates the inhibition of angiotensin II on the slowly activating delayed-rectifier potassium current through channel phosphorylation.

    Science.gov (United States)

    Gou, Xiangbo; Wang, Wenying; Zou, Sihao; Qi, Yajuan; Xu, Yanfang

    2018-03-01

    The slowly activating delayed rectifier K + current (I Ks ) is one of the main repolarizing currents in the human heart. Evidence has shown that angiotensin II (Ang II) regulates I Ks through the protein kinase C (PKC) pathway, but the related results are controversial. This study was designed to identify PKC isoenzymes involved in the regulation of I Ks by Ang II and the underlying molecular mechanism. The whole-cell patch-clamp technique was used to record I Ks in isolated guinea pig ventricular cardiomyocytes and in human embryonic kidney (HEK) 293 cells co-transfected with human KCNQ1/KCNE1 genes and Ang II type 1 receptor genes. Ang II inhibited I Ks in a concentration-dependent manner in native cardiomyocytes. A broad PKC inhibitor Gö6983 (not inhibiting PKCε) and a selective cPKC inhibitor Gö6976 did not affect the inhibitory action of Ang II. In contrast, the inhibition was significantly attenuated by PKCε-selective peptide inhibitor εV1-2. However, direct activation of PKC by phorbol 12-myristate 13-acetate (PMA) increased the cloned human I Ks in HEK293 cells. Similarly, the cPKC peptide activator significantly enhanced the current. In contrast, the PKCε peptide activator inhibited the current. Further evidence showed that PKCε knockdown by siRNA antagonized the Ang II-induced inhibition on KCNQ1/KCNE1 current, whereas knockdown of cPKCs (PKCα and PKCβ) attenuated the potentiation of the current by PMA. Moreover, deletion of four putative phosphorylation sites in the C-terminus of KCNQ1 abolished the action of PMA. Mutation of two putative phosphorylation sites in the N-terminus of KCNQ1 and one site in KCNE1 (S102) blocked the inhibition of Ang II. Our results demonstrate that PKCε isoenzyme mediates the inhibitory action of Ang II on I Ks and by phosphorylating distinct sites in KCNQ1/KCNE1, cPKC and PKCε isoenzymes produce the contrary regulatory effects on the channel. These findings have provided new insight into the molecular mechanism

  5. Contralateral delay activity provides a neural measure of the number of representations in visual working memory.

    Science.gov (United States)

    Ikkai, Akiko; McCollough, Andrew W; Vogel, Edward K

    2010-04-01

    Visual working memory (VWM) helps to temporarily represent information from the visual environment and is severely limited in capacity. Recent work has linked various forms of neural activity to the ongoing representations in VWM. One piece of evidence comes from human event-related potential studies, which find a sustained contralateral negativity during the retention period of VWM tasks. This contralateral delay activity (CDA) has previously been shown to increase in amplitude as the number of memory items increases, up to the individual's working memory capacity limit. However, significant alternative hypotheses remain regarding the true nature of this activity. Here we test whether the CDA is modulated by the perceptual requirements of the memory items as well as whether it is determined by the number of locations that are being attended within the display. Our results provide evidence against these two alternative accounts and instead strongly support the interpretation that this activity reflects the current number of objects that are being represented in VWM.

  6. A priori assumptions about characters as a cause of incongruence between molecular and morphological hypotheses of primate interrelationships.

    Science.gov (United States)

    Tornow, Matthew A; Skelton, Randall R

    2012-01-01

    When molecules and morphology produce incongruent hypotheses of primate interrelationships, the data are typically viewed as incompatible, and molecular hypotheses are often considered to be better indicators of phylogenetic history. However, it has been demonstrated that the choice of which taxa to include in cladistic analysis as well as assumptions about character weighting, character state transformation order, and outgroup choice all influence hypotheses of relationships and may positively influence tree topology, so that relationships between extant taxa are consistent with those found using molecular data. Thus, the source of incongruence between morphological and molecular trees may lie not in the morphological data themselves but in assumptions surrounding the ways characters evolve and their impact on cladistic analysis. In this study, we investigate the role that assumptions about character polarity and transformation order play in creating incongruence between primate phylogenies based on morphological data and those supported by multiple lines of molecular data. By releasing constraints imposed on published morphological analyses of primates from disparate clades and subjecting those data to parsimony analysis, we test the hypothesis that incongruence between morphology and molecules results from inherent flaws in morphological data. To quantify the difference between incongruent trees, we introduce a new method called branch slide distance (BSD). BSD mitigates many of the limitations attributed to other tree comparison methods, thus allowing for a more accurate measure of topological similarity. We find that releasing a priori constraints on character behavior often produces trees that are consistent with molecular trees. Case studies are presented that illustrate how congruence between molecules and unconstrained morphological data may provide insight into issues of polarity, transformation order, homology, and homoplasy.

  7. Alcohol Use among College Students: Some Competing Hypotheses.

    Science.gov (United States)

    Igra, Amnon; Moos, Rudolf H.

    1979-01-01

    Proximity of dormitory peers, involvement in informal social activities, and lack of commitment to religious and academic values were independently related to drinking and drinking onset. Formal involvement in college activities and psychological stress had no independent effect. (CP)

  8. Capacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Lorzadeh, Iman; Askarian Abyaneh, Hossein; Savaghebi, Mehdi

    2016-01-01

    Inductive-capacitive-inductive (LCL)-type line filters are widely used in grid-connected voltage source inverters (VSIs), since they can provide substantially improved attenuation of switching harmonics in currents injected into the grid with lower cost, weight and power losses than their L......-type counterparts. However, the inclusion of third order LCL network complicates the current control design regarding the system stability issues because of an inherent resonance peak which appears in the open-loop transfer function of the inverter control system near the control stability boundary. To avoid...... passive (resistive) resonance damping solutions, due to their additional power losses, active damping (AD) techniques are often applied with proper control algorithms in order to damp the LCL filter resonance and stabilize the system. Among these techniques, the capacitor current feedback (CCF) AD has...

  9. Intrahost Diversity of Feline Coronavirus: A Consensus between the Circulating Virulent/Avirulent Strains and the Internal Mutation Hypotheses?

    Directory of Open Access Journals (Sweden)

    Aline S. Hora

    2013-01-01

    Full Text Available To evaluate the most controversial issue concerning current feline coronavirus (FCoV virology, the coexisting hypotheses of the intrahost and interhost origins of feline infectious peritonitis virus (FIPV in regard to the pathogenesis of feline infectious peritonitis (FIP, this study aimed to assess the molecular diversity of the membrane gene FCoVs in 190 samples from 10 cats with signs of FIP and in 5 faecal samples from cats without signs of FIP. All samples from the non-FIP cats and 25.26% of the samples from the FIP cats were positive for the FCoV membrane (M gene. Mutations in this gene consisted of SNP changes randomly scattered among the sequences; few mutations resulted in amino acid changes. No geographic pattern was observed. Of the cats without FIP that harboured FECoV, the amino acid sequence identities for the M gene were 100% among cats (Cats 1–3 from the same cattery, and the overall sequence identity for the M gene was ≥91%. In one cat, two different lineages of FCoV, one enteric and one systemic, were found that segregated apart in the M gene tree. In conclusion, the in vivo mutation transition hypothesis and the circulating high virulent-low virulent FCoV hypothesis have been found to be plausible according to the results obtained from sequencing the M gene.

  10. Methadone, monoamine oxidase, and depression: opioid distribution and acute effects on enzyme activity

    International Nuclear Information System (INIS)

    Kaufmann, C.A.; Kreek, M.J.; Raghunath, J.; Arns, P.

    1983-01-01

    Narcotic withdrawal is often accompanied by an atypical depression which responds to resumption of narcotics. It was hypothesized that methadone might exert its antidepressant effects through monoamine oxidase (MAO) inhibition. The current study examined 3 H-methadone distribution in rat brain and effects on regional MAO activity with acute doses (2.5 mg/kg) which approximate those found during chronic methadone maintenance in man. Limbic areas (amygdala, basomedial hypothalamus, caudate-putamen, hippocampus, preoptic nucleus), as well as pituitary and liver were assayed for MAO activity and methadone concentration. MAO activities did not differ significantly in acute methadone or saline-treated cage-mates at 1 or 24 hr. The concentrations of methadone at 1 hr ranged between 17 and 223 ng/100 mg wet wt tissue in the preoptic nucleus and pituitary, respectively. No significant correlation was found between change in MAO activity (MAO methadone/MAO saline) and methadone concentration in any region at 1 or 24 hr. This study does not support the hypothesis that methadone acts as an antidepressant through MAO inhibition, at least not following acute administration of this exogenous opioid

  11. Factors that encourage females to pursue physical science careers: Testing five common hypotheses

    Science.gov (United States)

    Hazari, Zahra; Potvin, Geoff; Lock, Robynne M.; Lung, Florin; Sadler, Philip M.; Sonnert, Gerhard

    2012-03-01

    There are many hypotheses regarding factors that may encourage female students to pursue careers in the physical sciences. Using Propensity Score Matching (PSM) on national data (n=7505) drawn from the Persistence Research in Science and Engineering (PRiSE) project, we test five commonly held beliefs including having a single-sex physics class, having a female physics teacher, having female scientist guest speakers in physics class, discussing the work of women scientists in physics class, and discussing the under-representation of women in physics class. The effect of these experiences is compared for female students who are matched on several factors, including parental education, prior science/math interests, and academic background, thereby controlling for the effect of many confounding variables.

  12. Evaluation of hypotheses for the cause of the 1886 Charleston earthquake

    Energy Technology Data Exchange (ETDEWEB)

    White, R.M.; Long, L.T. (Law Environmental, Inc., Kennesaw, GA (USA); Georgia Inst. of Tech., Atlanta, GA (USA))

    1989-10-01

    This report describes a geophysical/geological investigation of the earth's crust at seismogenic depths in the Charleston, South Carolina area. This investigation was made for the purpose of narrowing the range of theories that have been used to explain the historic 1886 Charleston earthquake. Since a number of these theories are based on only a portion of the available data, we have established a comprehensive data set in order to allow these hypotheses to be subjected to the entire data set. Specifically, we combined existing and new gravity, magnetic and topographic data in grids of 128 km, 256 km and 1028 km on a side centered on Charleston. Seismic, geologic and drilling data were collected and summarized. A magnetotelluric survey consisting of 12 soundings interpreted to depths of over 40 kilometers defined the bottom of the rigid crust with assistance from seismic reflection and other data. A geologic model of the crust in the area of Charleston was constructed and it defined the locations of Triassic/Jurassic basins Paleozoic plutons in greater detail than has previously been achieved. 102 refs., 75 figs.

  13. Evaluation of hypotheses for the cause of the 1886 Charleston earthquake

    International Nuclear Information System (INIS)

    White, R.M.; Long, L.T.

    1989-10-01

    This report describes a geophysical/geological investigation of the earth's crust at seismogenic depths in the Charleston, South Carolina area. This investigation was made for the purpose of narrowing the range of theories that have been used to explain the historic 1886 Charleston earthquake. Since a number of these theories are based on only a portion of the available data, we have established a comprehensive data set in order to allow these hypotheses to be subjected to the entire data set. Specifically, we combined existing and new gravity, magnetic and topographic data in grids of 128 km, 256 km and 1028 km on a side centered on Charleston. Seismic, geologic and drilling data were collected and summarized. A magnetotelluric survey consisting of 12 soundings interpreted to depths of over 40 kilometers defined the bottom of the rigid crust with assistance from seismic reflection and other data. A geologic model of the crust in the area of Charleston was constructed and it defined the locations of Triassic/Jurassic basins Paleozoic plutons in greater detail than has previously been achieved. 102 refs., 75 figs

  14. Single-Phase LLCL-Filter-based Grid-Tied Inverter with Low-Pass Filter Based Capacitor Current Feedback Active damper

    DEFF Research Database (Denmark)

    Liu, Yuan; Wu, Weimin; Li, Yun

    2016-01-01

    The capacitor-current-feedback active damping method is attractive for high-order-filter-based high power grid-tied inverter when the grid impedance varies within a wide range. In order to improve the system control bandwidth and attenuate the high order grid background harmonics by using the quasi....... In this paper, a low pass filter is proposed to be inserted in the capacitor current feedback loop op LLCL-filter based grid-tied inverter together with a digital proportional and differential compensator. The detailed theoretical analysis is given. For verification, simulations on a 2kW/220V/10kHz LLCL...

  15. The Development and Current State of Translation Process Research

    DEFF Research Database (Denmark)

    Lykke Jakobsen, Arnt

    2014-01-01

    The development and current state of translation process research ch Arnt Lykke Jakobsen Copenhagen Business School lInterest in process-oriented translation studies has been intense for the past almost half a century. Translation process research (TPR) is the label we have used to refer to a spe...... itself, into regions like cognitive psychology, psycho- and neurolinguistics, and neuroscience, where the interest in what goes on in our heads is also very strong.......The development and current state of translation process research ch Arnt Lykke Jakobsen Copenhagen Business School lInterest in process-oriented translation studies has been intense for the past almost half a century. Translation process research (TPR) is the label we have used to refer...... which simultaneously tracks the translator’s eye movements across a screen displaying both a source text and the translator’s emerging translation. This research method was developed as a means of qualifying and strengthening translation process hypotheses based on verbal reports by providing additional...

  16. Nonlinear Hydroelastic Waves Generated due to a Floating Elastic Plate in a Current

    Directory of Open Access Journals (Sweden)

    Ping Wang

    2017-01-01

    Full Text Available Effects of underlying uniform current on the nonlinear hydroelastic waves generated due to an infinite floating plate are studied analytically, under the hypotheses that the fluid is homogeneous, incompressible, and inviscid. For the case of irrotational motion, the Laplace equation is the governing equation, with the boundary conditions expressing a balance among the hydrodynamics, the uniform current, and elastic force. It is found that the convergent series solutions, obtained by the homotopy analysis method (HAM, consist of the nonlinear hydroelastic wave profile and the velocity potential. The impacts of important physical parameters are discussed in detail. With the increment of the following current intensity, we find that the amplitudes of the hydroelastic waves decrease very slightly, while the opposing current produces the opposite effect on the hydroelastic waves. Furthermore, the amplitudes of waves increase very obviously for higher opposing current speed but reduce very slightly for higher following current speed. A larger amplitude of the incident wave increases the hydroelastic wave deflections for both opposing and following current, while for Young’s modulus of the plate there is the opposite effect.

  17. Re-activation of degraded nickel cermet anodes - Nano-particle formation via reverse current pulses

    Science.gov (United States)

    Hauch, A.; Marchese, M.; Lanzini, A.; Graves, C.

    2018-02-01

    The Ni/yttria-stabilized-zirconia (YSZ) cermet is the most commonly applied fuel electrode for solid oxide cells (SOCs). Loss of Ni/YSZ electrode activity is a key life-time limiting factor of the SOC. Developing means to mitigate this loss of performance or re-activate a fuel electrode is therefore important. In this work, we report a series of five tests on state-of-the-art Ni/YSZ-YSZ-CGObarrier-LSC/CGO cells. All cells were deliberately degraded via gas stream impurities in CO2/CO or harsh steam electrolysis operation. The cells were re-activated via a variety of reverse current treatments (RCTs). Via electrochemical impedance spectroscopy, we found that the Ni/YSZ electrode performance could be recovered via RCT, but not via constant fuel cell operation. For optimized RCT, we obtained a lower Ni/YSZ electrode resistance than the initial resistance. E.g. at 700 °C we measured fuel electrode resistance of 180 mΩ cm2, 390 mΩ cm2, and 159 mΩ cm2 before degradation, after degradation and after re-activation via RCT, respectively. Post-test SEM revealed that the RCT led to formation of nano-particles in the fuel electrode. Besides the remarkable improvement, the results also showed that RCTs can weaken Ni/YSZ interfaces and the electrode/electrolyte interface. This indicates that finding an optimum RCT profile is crucial for achieving maximum benefit.

  18. Transcranial direct current stimulation versus caffeine as a fatigue countermeasure.

    Science.gov (United States)

    McIntire, Lindsey K; McKinley, R Andy; Nelson, Justin M; Goodyear, Chuck

    To assess the efficacy of using transcranial direct current stimulation (tDCS) to remediate the deleterious effects of fatigue induced by sleep deprivation and compare these results to caffeine, a commonly used fatigue countermeasure. Based on previous research, tDCS of the dorsolateral prefrontal cortex (DLPFC) can modulate attention and arousal. The authors hypothesize that tDCS can be an effective fatigue countermeasure. Five groups of ten participants each received either active tDCS and placebo gum at 1800, caffeine gum with sham tDCS at 1800, active tDCS and placebo gum at 0400, caffeine gum with sham tDCS at 0400, or sham tDCS with placebo gum at 1800 and 0400 during 36-h of sustained wakefulness. Participants completed a vigilance task, working memory task, psychomotor vigilance task (PVT), and a procedural game beginning at 1800 h and continued every two hours throughout the night until 1900 the next day. tDCS dosed at 1800 provided 6 h of improved attentional accuracy and reaction times compared to the control group. Caffeine did not produce an effect. Both tDCS groups also had an improved effect on mood. Participants receiving tDCS reported feeling more vigor, less fatigue, and less bored throughout the night compared to the control and caffeine groups. We believe tDCS could be a powerful fatigue countermeasure. The effects appear to be comparable or possibly more beneficial than caffeine because they are longer lasting and mood remains more positive. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. EEG alpha rhythm, ocular activity and basal skin resistance

    NARCIS (Netherlands)

    Verbaten, M.N.; Beaujon, J.N.R.; Sjouw, W.

    Most hypotheses about the origin of the occipital alpha rhythm stress the specific influence of ocular activity. In this study, the influence of eye-movement frequency and extreme upward deviation of the eyeballs (enlarging the corneo-retinal potential) on occipital alpha activity and basal skin

  20. The Glycolytic Metabolite, Fructose-1,6-bisphosphate, Blocks Epileptiform Bursts by Attenuating Voltage-Activated Calcium Currents in Hippocampal Slices

    Directory of Open Access Journals (Sweden)

    Li-Rong Shao

    2018-06-01

    Full Text Available Manipulation of metabolic pathways (e.g., ketogenic diet (KD, glycolytic inhibition alters neural excitability and represents a novel strategy for treatment of drug-refractory seizures. We have previously shown that inhibition of glycolysis suppresses epileptiform activity in hippocampal slices. In the present study, we aimed to examine the role of a “branching” metabolic pathway stemming off glycolysis (i.e., the pentose-phosphate pathway, PPP in regulating seizure activity, by using a potent PPP stimulator and glycolytic intermediate, fructose-1,6-bisphosphate (F1,6BP. Employing electrophysiological approaches, we investigated the action of F1,6BP on epileptiform population bursts, intrinsic neuronal firing, glutamatergic and GABAergic synaptic transmission and voltage-activated calcium currents (ICa in the CA3 area of hippocampal slices. Bath application of F1,6BP (2.5–5 mM blocked epileptiform population bursts induced in Mg2+-free medium containing 4-aminopyridine, in ~2/3 of the slices. The blockade occurred relatively rapidly (~4 min, suggesting an extracellular mechanism. However, F1,6BP did not block spontaneous intrinsic firing of the CA3 neurons (when synaptic transmission was eliminated with DNQX, AP-5 and SR95531, nor did it significantly reduce AMPA or NMDA receptor-mediated excitatory postsynaptic currents (EPSCAMPA and EPSCNMDA. In contrast, F1,6BP caused moderate reduction (~50% in GABAA receptor-mediated current, suggesting it affects excitatory and inhibitory synapses differently. Finally and unexpectedly, F1,6BP consistently attenuated ICa by ~40% without altering channel activation or inactivation kinetics, which may explain its anticonvulsant action, at least in this in vitro seizure model. Consistent with these results, epileptiform population bursts in CA3 were readily blocked by the nonspecific Ca2+ channel blocker, CdCl2 (20 μM, suggesting that these bursts are calcium dependent. Altogether, these data

  1. Can MOND type hypotheses be tested in a free fall laboratory environment?

    Science.gov (United States)

    Das, Saurya; Patitsas, S. N.

    2013-05-01

    The extremely small accelerations of objects required for the onset of modified Newtonian dynamics, or modified Newtonian dynamics (MOND), makes testing the hypothesis in conventional terrestrial laboratories virtually impossible. This is due to the large background acceleration of Earth, which is transmitted to the acceleration of test objects within an apparatus. We show, however, that it may be possible to test MOND-type hypotheses with experiments using a conventional apparatus capable of tracking very small accelerations of its components but performed in locally inertial frames such as artificial satellites and other freely falling laboratories. For example, experiments involving an optical interferometer or a torsion balance in these laboratories would show nonlinear dynamics and displacement amplitudes larger than expected. These experiments may also be able to test potential violations of the strong equivalence principle by MOND and to distinguish between its two possible interpretations (modified inertia and modified gravity).

  2. Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes

    Energy Technology Data Exchange (ETDEWEB)

    Han, Myung-Geun, E-mail: mghan@bnl.gov [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Garlow, Joseph A. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794 (United States); Marshall, Matthew S.J.; Tiano, Amanda L. [Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Wong, Stanislaus S. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Cheong, Sang-Wook [Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854 (United States); Walker, Frederick J.; Ahn, Charles H. [Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520 (United States); Zhu, Yimei [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2017-05-15

    Highlights: • Electron-beam-induced-current (EBIC) and active secondary-electron voltage-contrast (SE-VC) are demonstrated in STEM mode combined with in situ electrical biasing in a TEM. • Electrostatic potential maps in ferroelectric thin films, multiferroic nanowires, and single crystals obtained by off-axis electron holography were compared with EBIC and SE-VC data. • Simultaneous EBIC and active SE-VC performed with atomic resolution STEM are demonstrated. - Abstract: The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.

  3. Brown trout in the Lees Ferry reach of the Colorado River—Evaluation of causal hypotheses and potential interventions

    Science.gov (United States)

    Runge, Michael C.; Yackulic, Charles B.; Bair, Lucas S.; Kennedy, Theodore A.; Valdez, Richard A.; Ellsworth, Craig; Kershner, Jeffrey L.; Rogers, R. Scott; Trammell, Melissa A.; Young, Kirk L.

    2018-04-17

    model, and without any changes to management, we predict there is a 36-percent chance the brown trout population at Lees Ferry will not show sustained growth, and will remain around a mean size of 5,800 adults, near its current size; in contrast, we predict there is a 64-percent chance that the population has a positive intrinsic growth rate and will increase 3–10 fold over the next 20 years. A humpback chub population model linked to the brown trout model suggests an increase of brown trout of this magnitude could lead to declines in the minimum adult humpback chub population over the same time period. Forecasts of rainbow trout abundance, however, suggest that increased abundance of brown trout in the Lees Ferry reach does not pose a threat to the rainbow trout fishery there. There are interventions that may be effective in moderating the growth of the brown trout population in the Lees Ferry reach of the Colorado River. Across causal hypotheses, we predict that removal strategies (for example, a concerted electrofishing effort or an incentivized take program targeted at large brown trout) could reduce brown trout abundance by approximately 50 percent relative to status quo management. Reductions in the frequency or a change in the seasonal timing of high-flow releases from Glen Canyon Dam could be even more effective, but only under the causal hypotheses that involve effects of such releases on immigration or reproduction. Brown trout management flows— dam releases designed to strand young fish at a vulnerable stage—may be able to reduce brown trout abundance to some degree, but are not forecast to be the most effective strategy under any causal hypothesis. We predict that the alternative management interventions would have effects on other resource goals as well, and the pattern of these effects differs across causal hypotheses. The removal strategies would incur direct costs (on the order of $7 million over 20 years) and the mechanical removal strategy is

  4. On the role of neutral flow in field-aligned currents

    Directory of Open Access Journals (Sweden)

    A. J. Mannucci

    2018-01-01

    Full Text Available In this brief note we explore the role of the neutral atmosphere in magnetosphere–ionosphere coupling. We analyze momentum balance in the ion rest frame to form hypotheses regarding the role of neutral momentum in the lower ionosphere during geomagnetic storms. Neutral momentum that appears in the ion rest frame is likely the result of momentum imparted to ionospheric ions by solar wind flow and the resultant magnetospheric dynamics. The resulting ion-neutral collisions lead to the existence of an electric field. Horizontal electron flow balances the momentum supplied by this electric field. We suggest a possible role played by the neutral atmosphere in generating field-aligned currents due to local auroral heating. Our physical interpretation suggests that thermospheric neutral dynamics plays a complementary role to the high-latitude field-aligned currents and electric fields resulting from magnetospheric dynamics.

  5. Current Management Strategy for Active Surveillance in Prostate Cancer.

    Science.gov (United States)

    Syed, Jamil S; Javier-Desloges, Juan; Tatzel, Stephanie; Bhagat, Ansh; Nguyen, Kevin A; Hwang, Kevin; Kim, Sarah; Sprenkle, Preston C

    2017-02-01

    Active surveillance has been increasingly utilized as a strategy for the management of favorable-risk, localized prostate cancer. In this review, we describe contemporary management strategies of active surveillance, with a focus on traditional stratification schemes, new prognostic tools, and patient outcomes. Patient selection, follow-up strategy, and indication for delayed intervention for active surveillance remain centered around PSA, digital rectal exam, and biopsy findings. Novel tools which include imaging, biomarkers, and genetic assays have been investigated as potential prognostic adjuncts; however, their role in active surveillance remains institutionally dependent. Although 30-50% of patients on active surveillance ultimately undergo delayed treatment, the vast majority will remain free of metastasis with a low risk of dying from prostate cancer. The optimal method for patient selection into active surveillance is unknown; however, cancer-specific mortality rates remain excellent. New prognostication tools are promising, and long-term prospective, randomized data regarding their use in active surveillance will be beneficial.

  6. The role of Patient Health Engagement Model (PHE-model in affecting patient activation and medication adherence: A structural equation model.

    Directory of Open Access Journals (Sweden)

    Guendalina Graffigna

    Full Text Available Increasing bodies of scientific research today examines the factors and interventions affecting patients' ability to self-manage and adhere to treatment. Patient activation is considered the most reliable indicator of patients' ability to manage health autonomously. Only a few studies have tried to assess the role of psychosocial factors in promoting patient activation. A more systematic modeling of the psychosocial factors explaining the variance of patient activation is needed.To test the hypothesized effect of patient activation on medication adherence; to test the the hypothesized effects of positive emotions and of the quality of the patient/doctor relationship on patient activation; and to test the hypothesized mediating effect of Patient Health Engagement (PHE-model in this pathway.This cross-sectional study involved 352 Italian-speaking adult chronic patients. The survey included measures of i patient activation (Patient Activation Measure 13 -short form; ii Patient Health Engagement model (Patient Health Engagement Scale; iii patient adherence (4 item-Morinsky Medication Adherence Scale; iv the quality of the patients' emotional feelings (Manikin Self Assessment Scale; v the quality of the patient/doctor relationship (Health Care Climate Questionnaire. Structural equation modeling was used to test the hypotheses proposed.According to the theoretical model we hypothesized, research results confirmed that patients' activation significantly affects their reported medication adherence. Moreover, psychosocial factors, such as the patients' quality of the emotional feelings and the quality of the patient/doctor relationship were demonstrated to be factors affecting the level of patient activation. Finally, the mediation effect of the Patient Health Engagement model was confirmed by the analysis.Consistently with the results of previous studies, these findings demonstrate that the Patient Health Engagement Model is a critical factor in

  7. The role of Patient Health Engagement Model (PHE-model) in affecting patient activation and medication adherence: A structural equation model.

    Science.gov (United States)

    Graffigna, Guendalina; Barello, Serena; Bonanomi, Andrea

    2017-01-01

    Increasing bodies of scientific research today examines the factors and interventions affecting patients' ability to self-manage and adhere to treatment. Patient activation is considered the most reliable indicator of patients' ability to manage health autonomously. Only a few studies have tried to assess the role of psychosocial factors in promoting patient activation. A more systematic modeling of the psychosocial factors explaining the variance of patient activation is needed. To test the hypothesized effect of patient activation on medication adherence; to test the the hypothesized effects of positive emotions and of the quality of the patient/doctor relationship on patient activation; and to test the hypothesized mediating effect of Patient Health Engagement (PHE-model) in this pathway. This cross-sectional study involved 352 Italian-speaking adult chronic patients. The survey included measures of i) patient activation (Patient Activation Measure 13 -short form); ii) Patient Health Engagement model (Patient Health Engagement Scale); iii) patient adherence (4 item-Morinsky Medication Adherence Scale); iv) the quality of the patients' emotional feelings (Manikin Self Assessment Scale); v) the quality of the patient/doctor relationship (Health Care Climate Questionnaire). Structural equation modeling was used to test the hypotheses proposed. According to the theoretical model we hypothesized, research results confirmed that patients' activation significantly affects their reported medication adherence. Moreover, psychosocial factors, such as the patients' quality of the emotional feelings and the quality of the patient/doctor relationship were demonstrated to be factors affecting the level of patient activation. Finally, the mediation effect of the Patient Health Engagement model was confirmed by the analysis. Consistently with the results of previous studies, these findings demonstrate that the Patient Health Engagement Model is a critical factor in enhancing

  8. Testing Biological Hypotheses with Embodied Robots: Adaptations, Accidents, and By-Products in the Evolution of Vertebrates

    OpenAIRE

    Roberts, Sonia F.; Hirokawa, Jonathan; Rosenblum, Hannah G.; Sakhtah, Hassan; Gutierrez, Andres A.; Porter, Marianne E.; Long, John H.

    2014-01-01

    Evolutionary robotics allows biologists to test hypotheses about extinct animals. In our case, we modeled some of the first vertebrates, jawless fishes, in order to study the evolution of the trait after which vertebrates are named: vertebrae. We tested the hypothesis that vertebrae are an adaptation for enhanced feeding and fleeing performance. We created a population of autonomous embodied robots, Preyro, in which the number of vertebrae, N, were free to evolve. In addition, two other trait...

  9. Hyperactivity in boys with attention deficit/hyperactivity disorder (ADHD): the association between deficient behavioral inhibition, attentional processes, and objectively measured activity.

    Science.gov (United States)

    Alderson, R Matt; Rapport, Mark D; Kasper, Lisa J; Sarver, Dustin E; Kofler, Michael J

    2012-01-01

    Contemporary models of ADHD hypothesize that hyperactivity reflects a byproduct of inhibition deficits. The current study investigated the relationship between children's motor activity and behavioral inhibition by experimentally manipulating demands placed on the limited-resource inhibition system. Twenty-two boys (ADHD = 11, TD = 11) between the ages of 8 and 12 years completed a conventional stop-signal task, two choice-task variants (no-tone, ignore-tone), and control tasks while their motor activity was measured objectively by actigraphs placed on their nondominant wrist and ankles. All children exhibited significantly higher activity rates under all three experimental tasks relative to control conditions, and children with ADHD moved significantly more than typically developing children across conditions. No differences in activity level were observed between the inhibition and noninhibition experimental tasks for either group, indicating that activity level was primarily associated with basic attentional rather than behavioral inhibition processes.

  10. Life History theory hypotheses on child growth: Potential implications for short and long-term child growth, development and health.

    Science.gov (United States)

    Said-Mohamed, Rihlat; Pettifor, John M; Norris, Shane A

    2018-01-01

    Life history theory integrates ecological, physiological, and molecular layers within an evolutionary framework to understand organisms' strategies to optimize survival and reproduction. Two life history hypotheses and their implications for child growth, development, and health (illustrated in the South African context) are reviewed here. One hypothesis suggests that there is an energy trade-off between linear growth and brain growth. Undernutrition in infancy and childhood may trigger adaptive physiological mechanisms prioritizing the brain at the expense of body growth. Another hypothesis is that the period from conception to infancy is a critical window of developmental plasticity of linear growth, the duration of which may vary between and within populations. The transition from infancy to childhood may mark the end of a critical window of opportunity for improving child growth. Both hypotheses emphasize the developmental plasticity of linear growth and the potential determinants of growth variability (including the role of parent-offspring conflict in maternal resources allocation). Implications of these hypotheses in populations with high burdens of undernutrition and infections are discussed. In South Africa, HIV/AIDS during pregnancy (associated with adverse birth outcomes, short duration of breastfeeding, and social consequences) may lead to a shortened window of developmental plasticity of growth. Furthermore, undernutrition and infectious diseases in children living in South Africa, a country undergoing a rapid nutrition transition, may have adverse consequences on individuals' cognitive abilities and risks of cardio-metabolic diseases. Studies are needed to identify physiological mechanisms underlying energy allocation between biological functions and their potential impacts on health. © 2017 Wiley Periodicals, Inc.

  11. Call transmission efficiency in native and invasive anurans: competing hypotheses of divergence in acoustic signals.

    Science.gov (United States)

    Llusia, Diego; Gómez, Miguel; Penna, Mario; Márquez, Rafael

    2013-01-01

    Invasive species are a leading cause of the current biodiversity decline, and hence examining the major traits favouring invasion is a key and long-standing goal of invasion biology. Despite the prominent role of the advertisement calls in sexual selection and reproduction, very little attention has been paid to the features of acoustic communication of invasive species in nonindigenous habitats and their potential impacts on native species. Here we compare for the first time the transmission efficiency of the advertisement calls of native and invasive species, searching for competitive advantages for acoustic communication and reproduction of introduced taxa, and providing insights into competing hypotheses in evolutionary divergence of acoustic signals: acoustic adaptation vs. morphological constraints. Using sound propagation experiments, we measured the attenuation rates of pure tones (0.2-5 kHz) and playback calls (Lithobates catesbeianus and Pelophylax perezi) across four distances (1, 2, 4, and 8 m) and over two substrates (water and soil) in seven Iberian localities. All factors considered (signal type, distance, substrate, and locality) affected transmission efficiency of acoustic signals, which was maximized with lower frequency sounds, shorter distances, and over water surface. Despite being broadcast in nonindigenous habitats, the advertisement calls of invasive L. catesbeianus were propagated more efficiently than those of the native species, in both aquatic and terrestrial substrates, and in most of the study sites. This implies absence of optimal relationship between native environments and propagation of acoustic signals in anurans, in contrast to what predicted by the acoustic adaptation hypothesis, and it might render these vertebrates particularly vulnerable to intrusion of invasive species producing low frequency signals, such as L. catesbeianus. Our findings suggest that mechanisms optimizing sound transmission in native habitat can play a less

  12. Call transmission efficiency in native and invasive anurans: competing hypotheses of divergence in acoustic signals.

    Directory of Open Access Journals (Sweden)

    Diego Llusia

    Full Text Available Invasive species are a leading cause of the current biodiversity decline, and hence examining the major traits favouring invasion is a key and long-standing goal of invasion biology. Despite the prominent role of the advertisement calls in sexual selection and reproduction, very little attention has been paid to the features of acoustic communication of invasive species in nonindigenous habitats and their potential impacts on native species. Here we compare for the first time the transmission efficiency of the advertisement calls of native and invasive species, searching for competitive advantages for acoustic communication and reproduction of introduced taxa, and providing insights into competing hypotheses in evolutionary divergence of acoustic signals: acoustic adaptation vs. morphological constraints. Using sound propagation experiments, we measured the attenuation rates of pure tones (0.2-5 kHz and playback calls (Lithobates catesbeianus and Pelophylax perezi across four distances (1, 2, 4, and 8 m and over two substrates (water and soil in seven Iberian localities. All factors considered (signal type, distance, substrate, and locality affected transmission efficiency of acoustic signals, which was maximized with lower frequency sounds, shorter distances, and over water surface. Despite being broadcast in nonindigenous habitats, the advertisement calls of invasive L. catesbeianus were propagated more efficiently than those of the native species, in both aquatic and terrestrial substrates, and in most of the study sites. This implies absence of optimal relationship between native environments and propagation of acoustic signals in anurans, in contrast to what predicted by the acoustic adaptation hypothesis, and it might render these vertebrates particularly vulnerable to intrusion of invasive species producing low frequency signals, such as L. catesbeianus. Our findings suggest that mechanisms optimizing sound transmission in native habitat

  13. Trait approach and avoidance motivation: lateralized neural activity associated with executive function.

    Science.gov (United States)

    Spielberg, Jeffrey M; Miller, Gregory A; Engels, Anna S; Herrington, John D; Sutton, Bradley P; Banich, Marie T; Heller, Wendy

    2011-01-01

    Motivation and executive function are both necessary for the completion of goal-directed behavior. Research investigating the manner in which these processes interact is beginning to emerge and has implicated middle frontal gyrus (MFG) as a site of interaction for relevant neural mechanisms. However, this research has focused on state motivation, and it has not examined functional lateralization. The present study examined the impact of trait levels of approach and avoidance motivation on neural processes associated with executive function. Functional magnetic resonance imaging was conducted while participants performed a color-word Stroop task. Analyses identified brain regions in which trait approach and avoidance motivation (measured by questionnaires) moderated activation associated with executive control. Approach was hypothesized to be associated with left-lateralized MFG activation, whereas avoidance was hypothesized to be associated with right-lateralized MFG activation. Results supported both hypotheses. Present findings implicate areas of middle frontal gyrus in top-down control to guide behavior in accordance with motivational goals. Copyright © 2010 Elsevier Inc. All rights reserved.

  14. Nonlinear current diffusion in type-II superconductors

    International Nuclear Information System (INIS)

    Beek, C.J. van der; Nieuwenhuys, G.J.; Kes, P.H.; Schnack, H.G.; Griessen, R.

    1992-01-01

    The temporal evolution of flux profiles in superconducting slabs and cylinders is investigated numerically for the situation where the flux-creep activation barrier U depends explicitly on current density j, e.g., U(j) ∝ [(j c /j) μ -1] or U(j)∝ln(j c /j). Both field-independent and field-dependent forms of the critical current density j c are considered. Exact numerical results for the time-dependent magnetization and relaxation time τ are compared to approximate analytical solutions. When the flux-creep activation barrier diverges as j → 0, flux- and current-density profiles evolve towards an asymptotic behaviour that is independent of initial conditions. The time-dependent magnetization in the case of full flux penetration is then well described by the appropriate form for the magnetization of the sample in the critical state, but with a time-dependent surface current density replacing the critical current density. The current-dependent flux-creep activation barrier may be obtained from low-temperature experiments using the analysis method of Maley et al., even when j c depends explicitly on B. (orig.)

  15. Overview of the current and planned activities in the French underground research laboratory at Bure

    International Nuclear Information System (INIS)

    Delay, J.

    2006-01-01

    In November 1999 Andra began building an Underground Research Laboratory (URL) on the border of the Meuse and Haute-Marne departments in eastern France. The research activities of the URL are dedicated to reversible, deep geological disposal of high-activity, long-lived radioactive wastes in an argillaceous host rock. The studies covered four complementary aspects: acquisition of data (waste packages, material behaviour and clay medium), repository design and reversibility studies, analysis of the long term behaviour of the repository, safety analyses. For the next phase starting in 2007, Andra will carry out integrated tests of a technological scope, i.e. trial drift, demonstrator of current drift. The results should make it possible to assess the safety of a disposal over several tens and even hundreds of thousands of years and submit in 2015 a file for permission request for the HLW and ILW deep disposal. (author)

  16. Astrocytic actions on extrasynaptic neuronal currents

    Directory of Open Access Journals (Sweden)

    Balazs ePal

    2015-12-01

    Full Text Available In the last few decades, knowledge about astrocytic functions has significantly increased. It was demonstrated that astrocytes are not passive elements of the central nervous system, but active partners of neurons. There is a growing body of knowledge about the calcium excitability of astrocytes, the actions of different gliotransmitters and their release mechanisms, as well as the participation of astrocytes in the regulation of synaptic functions and their contribution to synaptic plasticity. However, astrocytic functions are even more complex than being a partner of the 'tripartite synapse', as they can influence extrasynaptic neuronal currents either by releasing substances or regulating ambient neurotransmitter levels. Several types of currents or changes of membrane potential with different kinetics and via different mechanisms can be elicited by astrocytic activity. Astrocyte-dependent phasic or tonic, inward or outward currents were described in several brain areas. Such currents, together with the synaptic actions of astrocytes, can contribute to neuromodulatory mechanisms, neurosensory and –secretory processes, cortical oscillatory activity, memory and learning or overall neuronal excitability. This mini-review is an attempt to give a brief summary of astrocyte-dependent extrasynaptic neuronal currents and their possible functional significance.

  17. Transformer current sensor for superconducting magnetic coils

    Science.gov (United States)

    Shen, S.S.; Wilson, C.T.

    1985-04-16

    The present invention is a current transformer for operating currents larger than 2kA (two kiloamps) that is capable of detecting a millivolt level resistive voltage in the presence of a large inductive voltage. Specifically, the present invention includes substantially cylindrical primary turns arranged to carry a primary current and substantially cylindrical secondary turns arranged coaxially with and only partially within the primary turns, the secondary turns including an active winding and a dummy winding, the active and dummy windings being coaxial, longitudinally separated and arranged to mutually cancel voltages excited by commonly experienced magnetic fields, the active winding but not the dummy winding being arranged within the primary turns.

  18. Current activities at the FiR 1 TRIGA reactor

    International Nuclear Information System (INIS)

    Salmenhaara, Seppo

    2002-01-01

    The FiR 1 -reactor, a 250 kW Triga reactor, has been in operation since 1962. The main purpose to run the reactor is now the Boron Neutron Capture Therapy (BNCT). The epithermal neutrons needed for the irradiation of brain tumor patients are produced from the fast fission neutrons by a moderator block consisting of Al+AlF 3 (FLUENTAL), which showed to be the optimum material for this purpose. Twenty-one patients have been treated since May 1999, when the license for patient treatment was granted to the responsible BNCT treatment organization. The treatment organization has a close connection to the Helsinki University Central Hospital. The BNCT work dominates the current utilization of the reactor: three days per week for BNCT purposes and only two days per week for other purposes such as the neutron activation analysis and isotope production. In the near future the back end solutions of the spent fuel management will have a very important role in our activities. The Finnish Parliament ratified in May 2001 the Decision in Principle on the final disposal facility for spent fuel in Olkiluoto, on the western coast of Finland. There is a special condition in our operating license. We have now about two years' time to achieve a binding agreement between VTT and the Nuclear Power Plant Companies about the possibility to use the final disposal facility of the Nuclear Power Plants for our spent fuel. If this will not happen, we have to make the agreement with the USDOE with the well-known time limits. At the moment it seems to be reasonable to prepare for both spent fuel management possibilities: the domestic final disposal and the return to the USA offered by USDOE. Because the cost estimates of the both possibilities are on the same order of magnitude, the future of the reactor itself will determine, which of the spent fuel policies will be obeyed. In a couple of years' time it will be seen, if the funding of the reactor and the incomes from the BNC treatments will cover

  19. Oxygen reduction activity of carbon fibers cathode, and application for current generation from the NAD+ and NADH recycling reaction

    Directory of Open Access Journals (Sweden)

    H. Maeda

    2012-03-01

    Full Text Available Carbon fibers treated at 700 oC for 10 min were found to have O2 reduction activity when being used as a cathode. The special type of partition combined with both cationic and anionic exchange membranes was applied between anode cell and cathode cell in order to use a highly acidic solution such as 0.5 M H2SO4 as an electrolyte of the cathode cell for increasing the efficiency of O2 reduction activity. The current generation from NAD+ and NADH recycling system combined with D-gluconolactone production from 500 mg of D-glucose was performed by applying only carbon fibers for both anode and cathode. The total current volume obtained was 81.4 mAh during the reaction for 10 h, and the current efficiency was 93%. One gram of carbon fibers was pressed with Nafion paste on a piece of carbon paper(area : 50 mm×50mm with heating to prepare the cathode, and this construct was combined with conventional fuel cell. The power density was 3.6 mW/cm2, and the total power volume was calculated to be 90 mW per 1 g of carbon fibers.

  20. Activity-dependent modulation of neural circuit synaptic connectivity

    Directory of Open Access Journals (Sweden)

    Charles R Tessier

    2009-07-01

    Full Text Available In many nervous systems, the establishment of neural circuits is known to proceed via a two-stage process; 1 early, activity-independent wiring to produce a rough map characterized by excessive synaptic connections, and 2 subsequent, use-dependent pruning to eliminate inappropriate connections and reinforce maintained synapses. In invertebrates, however, evidence of the activity-dependent phase of synaptic refinement has been elusive, and the dogma has long been that invertebrate circuits are “hard-wired” in a purely activity-independent manner. This conclusion has been challenged recently through the use of new transgenic tools employed in the powerful Drosophila system, which have allowed unprecedented temporal control and single neuron imaging resolution. These recent studies reveal that activity-dependent mechanisms are indeed required to refine circuit maps in Drosophila during precise, restricted windows of late-phase development. Such mechanisms of circuit refinement may be key to understanding a number of human neurological diseases, including developmental disorders such as Fragile X syndrome (FXS and autism, which are hypothesized to result from defects in synaptic connectivity and activity-dependent circuit function. This review focuses on our current understanding of activity-dependent synaptic connectivity in Drosophila, primarily through analyzing the role of the fragile X mental retardation protein (FMRP in the Drosophila FXS disease model. The particular emphasis of this review is on the expanding array of new genetically-encoded tools that are allowing cellular events and molecular players to be dissected with ever greater precision and detail.

  1. Autowaves in an active two-wire line with exponential current-voltage characteristics

    International Nuclear Information System (INIS)

    Zhuravlev, V. M.

    2006-01-01

    Nonlinear wave processes in two-wire lines containing an active element with an exponential current-voltage characteristic (CVC) similar to that of a p-n junction are investigated. These lines are models of systems that are encountered in various physical and biological applications, such as biological membranes and semiconductor devices. It is shown that such systems may operate in different modes each of which has different dispersion and dissipation properties and, as a consequence, is described by autowave processes of different types. The behavior of a system in all basic modes is analyzed. For each mode, exact solutions to relevant equations are found and their differential conservation laws and intrinsic symmetries are investigated. One of common properties of such equations is the presence of a special superposition principle that describes the discrete structure of excitations in a line that consist of individual elementary excitations. It is shown that autopulses may be generated in such systems

  2. Considerations on the mechanism of action of artemisinin antimalarials: part 1--the 'carbon radical' and 'heme' hypotheses.

    Science.gov (United States)

    Haynes, Richard K; Cheu, Kwan-Wing; N'Da, David; Coghi, Paolo; Monti, Diego

    2013-08-01

    The isolation of artemisinin from the traditional medicinal herb qīng hāo (Artemisia annua), its characterization as a peroxide and preparation of the derivatives dihydroartemisinin, artemether and artesunate in the 1970s and 1980s by Chinese scientists under the umbrella of Project 523 collectively represents one of the great events in medicine in the latter third of the 20(th) Century. Artemisinins have become the most important component of chemotherapy of malaria: although used initially in monotherapy, they are now used in combination therapies or ACTs with longer half-life quinolines or arylmethanols. Nevertheless, the recent emergence of artemisinin-tolerant strains of the malaria parasite as reflected in increased clearance times of parasitaemia in patients treated with ACTs represents the greatest threat to control of malaria since resistance to chloroquine was first reported over 55 years ago. Importantly, the event brings into sharp focus the realization that relatively little is precisely understood, as opposed to widely assumed, for the mechanism of drug action of artemisinins and their synthetic peroxide analogues. Thus, we review here their antimalarial activities, the use of artemisinins in combination therapies, drug-drug interactions with the quinolines and arylmethanols, and metabolism of the artemisinins and synthetic peroxides. The mechanism of action of quinolines and arylmethanols, in particular their ability to induce redistribution of heme into the parasite cytosol, is also highlighted. This collective information is then used as a counterpoint to screen the validity of two of the prevailing hypotheses of drug action of artemisinins and synthetic peroxides, namely i. 'the C-radical hypothesis' wherein the peroxide undergoes 'bioactivation' by ferrous iron to generate C-radicals that are held to be the cytotoxic agents and ii. the 'heme hypothesis' wherein ferrous heme may generate either the same type of 'cytotoxic' C-radical, or the

  3. Sub-kilometre (intra-crater) mounds in Utopia Planitia, Mars: character, occurrence and possible formation hypotheses

    Science.gov (United States)

    Soare, Richard J.; Conway, Susan J.; Pearce, Geoffrey D.; Costard, François; Séjourné, Antoine

    2013-08-01

    At the middle latitudes of Utopia Planitia (˜35-45°N; ˜65-101°E) hundreds of small-sized mounds located in sub-kilometre impact craters dot the landscape. Their shape varies from circular to crescentic and their height ranges from ˜10 to 50 m. Often, metre to decametre pitting is observed, as is metres-thick banding or stratification. Mound albedo is relatively high, i.e. ˜0.16. The plain's terrain in the region, previously linked to the latitude-dependent mantle (LDM) of ice-dust, displays pitting and albedo similar to the small intra-crater mounds. Some workers have suggested that the mounds and the plain's terrain share a common ice-dust origin. If so, then scrutinising the mounds could provide analogical insight on the key geological characteristics and spatial distribution of the LDM itself. Other workers have hypothesised that the mounds are eroded sedimentary landforms or periglacial mounds underlain by a perennial ice-core (closed-system pingos). In this article we develop and then discuss each of the three mound-hypotheses in a much more substantial manner than has been done hitherto. Towards this end we use high-resolution images, present a detailed regional-map of mound distribution and establish a regional platform of topographical analysis using MOLA data superposed on a large-scale CTX mosaic. Although the ice-dust hypothesis is consistent with some observations and measurements, we find that a (loess-based) sedimentary hypothesis shows greater plausibility. Of the three hypotheses evaluated, the pingo or periglacial one is the weakest.

  4. Replicated population divergence caused by localized coevolution? A test of three hypotheses in the red crossbill-lodgepole pine system.

    Science.gov (United States)

    Edelaar, P; Benkman, C W

    2006-09-01

    Several lines of evidence support the hypothesis that local populations of red crossbills (Loxia curvirostra complex) enter into a predator-prey arms race with lodgepole pine (Pinus contorta latifolia) in the absence of competing pine squirrels (Tamiasciurus hudsonicus). Nevertheless, the alternative hypotheses that neutral evolution or factors other than squirrels have caused crossbill population differentiation have not been thoroughly tested. We compared crossbill and pine cone morphology between island populations where squirrels are absent or present, and mainland sites where squirrels are present, in order to distinguish among these hypotheses. All comparisons supported an effect of squirrel absence, not island status, on crossbill and cone morphology. Hence our results provide further evidence that strong localized coevolutionary interactions in a geographic mosaic have driven adaptive population differentiation. In addition, vocal differentiation of crossbills was related to the absence of squirrels, but not to island status. As morphological and vocal differentiation is correlated with reproductive isolation in crossbills, the geographic mosaic of coevolution also seems to promote ecological speciation.

  5. Critical current density, irreversibility line, and flux creep activation energy in silver-sheathed Bi2Sr2Ca2Cu3Ox superconducting tapes

    International Nuclear Information System (INIS)

    Shi, D.; Wang, Z.; Sengupta, S.; Smith, M.; Goodrich, L.F.; Dou, S.X.; Liu, H.K.; Guo, Y.C.

    1992-08-01

    Transport data, magnetic hysteresis and flux creep activation energy experimental results are presented for silver-sheathed high-T c Bi 2 Sr 2 Ca 2 Cu 3 O x superconducting tapes. The 110 K superconducting phase was formed by lead doping in a Bi-Sr-Ca-Cu-0 system. The transport critical current density was measured at 4.0 K to be 0.7 x 10 5 A/cm 2 (the corresponding critical current is 74 A) at zero field and 1.6 x 10 4 A/cm 2 at 12 T for H parallel ab. Excellent grain alignment in the a-b plane was achieved by a short-melting method, which considerably improved the critical current density and irreversibility line. Flux creep activation energy as a function of current is obtained based on the magnetic relaxation measurements

  6. Purification of Active Myrosinase from Plants by Aqueous Two-Phase Counter-Current Chromatography

    Science.gov (United States)

    Wade, Kristina L.; Ito, Yoichiro; Ramarathnam, Aarthi; Holtzclaw, W. David; Fahey, Jed W.

    2014-01-01

    Introduction Myrosinase (thioglucoside glucohydrolase; E.C. 3.2.1.147), is a plant enzyme of increasing interest and importance to the biomedical community. Myrosinase catalyses the formation of isothiocyanates such as sulforaphane (frombroccoli) and 4-(α-l-rhamnopyranosyloxy)benzyl isothiocyanate (from moringa), which are potent inducers of the cytoprotective phase-2 response in humans, by hydrolysis of their abundant glucosinolate (β-thioglucoside N-hydroxysulphate) precursors. Objective To develop an aqueous two-phase counter-current chromatography (CCC) system for the rapid, three-step purification of catalytically active myrosinase. Methods A high-concentration potassium phosphate and polyethylene glycol biphasic aqueous two-phase system (ATPS) is used with a newly developed CCC configuration that utilises spiral-wound, flat-twisted tubing (with an ovoid cross-section). Results Making the initial crude plant extract directly in the ATPS and injecting only the lower phase permitted highly selective partitioning of the myrosinase complex before a short chromatography on a spiral disk CCC. Optimum phase retention and separation of myrosinase from other plant proteins afforded a 60-fold purification. Conclusion Catalytically active myrosinase is purified from 3-day broccoli sprouts, 7-day daikon sprouts, mustard seeds and the leaves of field-grown moringa trees, in a CCC system that is predictably scalable. PMID:25130502

  7. Purification of active myrosinase from plants by aqueous two-phase counter-current chromatography.

    Science.gov (United States)

    Wade, Kristina L; Ito, Yoichiro; Ramarathnam, Aarthi; Holtzclaw, W David; Fahey, Jed W

    2015-01-01

    Myrosinase (thioglucoside glucohydrolase; E.C. 3.2.1.147), is a plant enzyme of increasing interest and importance to the biomedical community. Myrosinase catalyses the formation of isothiocyanates such as sulforaphane (from broccoli) and 4-(α-l-rhamnopyranosyloxy)benzyl isothiocyanate (from moringa), which are potent inducers of the cytoprotective phase-2 response in humans, by hydrolysis of their abundant glucosinolate (β-thioglucoside N-hydroxysulphate) precursors. To develop an aqueous two-phase counter-current chromatography (CCC) system for the rapid, three-step purification of catalytically active myrosinase. A high-concentration potassium phosphate and polyethylene glycol biphasic aqueous two-phase system (ATPS) is used with a newly developed CCC configuration that utilises spiral-wound, flat-twisted tubing (with an ovoid cross-section). Making the initial crude plant extract directly in the ATPS and injecting only the lower phase permitted highly selective partitioning of the myrosinase complex before a short chromatography on a spiral disk CCC. Optimum phase retention and separation of myrosinase from other plant proteins afforded a 60-fold purification. Catalytically active myrosinase is purified from 3-day broccoli sprouts, 7-day daikon sprouts, mustard seeds and the leaves of field-grown moringa trees, in a CCC system that is predictably scalable. Copyright © 2014 John Wiley & Sons, Ltd.

  8. Comparison of antimalarial activity of Artemisia turanica extract with current drugs in vivo.

    Science.gov (United States)

    Taherkhani, Mahboubeh; Rustaiyan, Abdolhossein; Nahrevanian, Hossein; Naeimi, Sabah; Taherkhani, Tofigh

    2013-03-01

    The purpose of this study was to compare antimalarial activity of Artemisia turanica Krasch as Iranian flora with current antimalarial drugs against Plasmodium berghei in vivo in mice. Air-dried aerial parts of Iranian flora A. turanica were collected from Khorasan, northeastern Iran, extracted with Et2O/MeOH/Petrol and defatted. Toxicity of herbal extracts was assessed on male NMRI mice, and their antimalarial efficacy was compared with antimalarial drugs [artemether, chloroquine and sulfadoxinepyrimethamine (Fansidar)] on infected P. berghei animals. All the groups were investigated for parasitaemia, body weight, hepatomegaly, splenomegaly and anemia. The significance of differences was determined by Analysis of Variances (ANOVA) and Student's t-test using Graph Pad Prism software. The inhibitory effects of A. turanica extract on early decline of P. berghei parasitaemia highlights its antimalarial activity, however, this effect no longer can be observed in the late infection. This may be due to the metabolic process of A. turanica crude extract by mice and reduction of its concentration in the body. Crude extract of A. turanica represented its antisymptomatic effects by stabilization of body, liver and spleen weights. This study confirmed antimalarial effects of A. turanica extracts against murine malaria in vivo during early infection, however, there are more benefits on pathophysiological symptoms by this medication.

  9. Bumetanide increases Cl--dependent short-circuit current in late distal colon: Evidence for the presence of active electrogenic Cl- absorption.

    Science.gov (United States)

    Tang, Lieqi; Fang, Xiefan; Winesett, Steven P; Cheng, Catherine Y; Binder, Henry J; Rivkees, Scott A; Cheng, Sam X

    2017-01-01

    Mammalian colonic epithelia consist of cells that are capable of both absorbing and secreting Cl-. The present studies employing Ussing chamber technique identified two opposing short-circuit current (Isc) responses to basolateral bumetanide in rat distal colon. Apart from the transepithelial Cl--secretory Isc in early distal colon that was inhibited by bumetanide, bumetanide also stimulated Isc in late distal colon that had not previously been identified. Since bumetanide inhibits basolateral Na+-K+-2Cl- cotransporter (NKCC) in crypt cells and basolateral K+-Cl- cotransporter (KCC) in surface epithelium, we proposed this stimulatory Isc could represent a KCC-mediated Cl- absorptive current. In support of this hypothesis, ion substitution experiments established Cl- dependency of this absorptive Isc and transport inhibitor studies demonstrated the involvement of an apical Cl- conductance. Current distribution and RNA sequencing analyses revealed that this Cl- absorptive Isc is closely associated with epithelial Na+ channel (ENaC) but is not dependent on ENaC activity. Thus, inhibition of ENaC by 10 μM amiloride or benzamil neither altered the direction nor its activity. Physiological studies suggested that this Cl- absorptive Isc senses dietary Cl- content; thus when dietary Cl- was low, Cl- absorptive Isc was up-regulated. In contrast, when dietary Cl- was increased, Cl- absorptive Isc was down-regulated. We conclude that an active Cl- extrusion mechanism exists in ENaC-expressing late distal colon and likely operates in parallel with ENaC to facilitate NaCl absorption.

  10. The actions of mdivi-1, an inhibitor of mitochondrial fission, on rapidly activating delayed-rectifier K⁺ current and membrane potential in HL-1 murine atrial cardiomyocytes.

    Science.gov (United States)

    So, Edmund Cheung; Hsing, Chung-Hsi; Liang, Chia-Hua; Wu, Sheng-Nan

    2012-05-15

    Mdivi-1 is an inhibitor of dynamin related protein 1- (drp1)-mediated mitochondrial fission. However, the mechanisms through which this compound interacts directly with ion currents in heart cells remain unknown. In this study, its effects on ion currents and membrane potential in murine HL-1 cardiomyocytes were investigated. In whole-cell recordings, the addition of mdivi-1 decreased the amplitude of tail current (I(tail)) for the rapidly activating delayed-rectifier K⁺ current (I(Kr)) in a concentration-dependent manner with an IC₅₀ value at 11.6 μM, a value that resembles the inhibition requirement for mitochondrial division. It shifted the activation curve of I(tail) to depolarized voltages with no change in the gating charge. However, mdivi-1 did not alter the rate of recovery from current inactivation. In cell-attached configuration, mdivi-1 inside the pipette suppressed the activity of acetylcholine-activated K⁺ channels without modifying the single-channel conductance. Mdivi-1 (30 μM) slightly depressed the peak amplitude of Na⁺ current with no change in the overall current-voltage relationship. Under current-clamp recordings, addition of mdivi-1 resulted in prolongation for the duration of action potentials (APs) and to increase the firing of spontaneous APs in HL-1 cells. Similarly, in pituitary GH₃ cells, mdivi-1 was effective in directly suppressing the amplitude of ether-à-go-go-related gene-mediated K⁺ current. Therefore, the lengthening of AP duration and increased firing of APs caused by mdivi-1 can be primarily explained by its inhibition of these K⁺ channels enriched in heart cells. The observed effects of mdivi-1 on ion currents were direct and not associated with its inhibition of mitochondrial division. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Current status and issues of nuclear human resource development/General activities of Japan nuclear human resource development network

    International Nuclear Information System (INIS)

    Murakami, Hiroyuki; Hino, Sadami; Tsuru, Hisanori

    2013-01-01

    The Japan Nuclear Human Resource Development Network (JN-HRD Net) was established in November 2010 with the aim of developing a framework for mutual cooperation and information sharing among nuclear-related organizations. Although the tasks and goals of developing human resources in the nuclear field have been shifted since the accident at the Tokyo Electric Power Company (TEPCO) Fukushima Daiichi Nuclear Power Plant, the necessity of fostering capable personnel in this field stays unchanged and the importance of our network activities has further emphasized. The meeting of JN-HRD Net was held on the 5th of February 2013, where its activities by each field were reported and views and opinions were actively exchanged between more than 90 participants. This paper briefly describes current status and issues of JN-HRD Net and its general activities conducted by the JN-HRD Net secretariat. (J.P.N.)

  12. The Problematics of Implementing Innovation Activities by National Economic Actors in Conditions of the Currently Effective Legislation

    Directory of Open Access Journals (Sweden)

    Nosovets Oleksandra I.

    2017-07-01

    Full Text Available The article reviews the problematics of current effective legislation on the issues of regulating the innovation activities as to assessing the extent of obstacles and the ways of eliminating them, along with encouraging enterprises to move from an innovative focus to the actual commercialization of innovations. Systems of facilitating as well as impediment factors for the corresponding economic activities in Ukraine are presented in the format of grouping and structuring the elements of influence according to the principle of subordination of relations between them together with description of «bottlenecks» in the legal support and institutional provision, in the financing and preparedness of business entities to implement innovations. The chain of appearance of the low quality innovation supply in the marketplace starting from actors in innovative processes and weak formation of innovation demand for the transition to an innovative type of entrepreneurial activity has been substantiated.

  13. Coordination of Project and Current Activities on the Basis of the Strategy Alignment Metamodel in the Oil and Gas Company

    Directory of Open Access Journals (Sweden)

    R. Yu. Dashkov

    2017-01-01

    Full Text Available Purpose: the purpose of this article is to describe the Strategy Alignment Metamodel of the project and current activities, which allows us to connect the Goals and Strategies for Phases of the project with the Goals and Strategies of the company at all levels of the organization through targeted measurement and application of Interpretive Models. Building Networks of Goals and Strategies, and adopting organizational solutions, you coordinate the interaction of the Project office and departments of the company. This methodology is based on a Logical Rationale of the Contexts and Assumptions for establishing Goals and Strategies both for the project and for the company, and on preparation of Contexts and Assumptions, Goals and Strategies Alignment Matrices, which provides a flexible adaptation to the internal and external environment in the process of selecting the most successful Strategies to achieve the Goals. Methods: this article is based on the concept of Goals-Questions-Metrics+ Strategies, which is adapted as another concept of strategic monitoring and control system of projects: Goals-Phases-Metrics+Strategies. These concepts have formed the basis of the Strategy Alignment Metamodel, where a technology of Phases Earned Value Management is used as a measurement system for the project activity, and Balanced scorecard is applied for current operations. Results: strategy Alignment Metamodel of the project and current activities of the company is proposed hereby. It uses modern strategic monitoring and control systems for projects: Goals-Phases-Metrics+Strategies, and for the company: Goals-Questions-Metrics+ Strategies. The interaction between these systems is based on Contexts and Assumptions, Goals and Strategies Alignment Matrices. The existence of such matrices greatly simplifies management decisions and prevents the risk of delays in the execution of project Phases based on rational participation and coordination of the company</