Sample records for dysmetria experimental evidence

  1. Mechanisms of human cerebellar dysmetria: experimental evidence and current conceptual bases

    PubMed Central

    Manto, Mario

    2009-01-01

    The human cerebellum contains more neurons than any other region in the brain and is a major actor in motor control. Cerebellar circuitry is unique by its stereotyped architecture and its modular organization. Understanding the motor codes underlying the organization of limb movement and the rules of signal processing applied by the cerebellar circuits remains a major challenge for the forthcoming decades. One of the cardinal deficits observed in cerebellar patients is dysmetria, designating the inability to perform accurate movements. Patients overshoot (hypermetria) or undershoot (hypometria) the aimed target during voluntary goal-directed tasks. The mechanisms of cerebellar dysmetria are reviewed, with an emphasis on the roles of cerebellar pathways in controlling fundamental aspects of movement control such as anticipation, timing of motor commands, sensorimotor synchronization, maintenance of sensorimotor associations and tuning of the magnitudes of muscle activities. An overview of recent advances in our understanding of the contribution of cerebellar circuitry in the elaboration and shaping of motor commands is provided, with a discussion on the relevant anatomy, the results of the neurophysiological studies, and the computational models which have been proposed to approach cerebellar function. PMID:19364396

  2. Rehabilitation of the Pontine Ataxia-Dysmetria Syndrome.

    PubMed

    Li, Stephanie; Hartman, Kasondra; Surapaneni, Krishna; Altschuler, Eric L

    2017-06-01

    We present a case of a patient with significant ataxia and dysmetria following a lacunar pontine infarction and review the literature on this uncommon syndrome. The patient had an excellent clinical course with near resolution of symptoms and signs in less than 3 weeks. We illustrate the patient's ataxia and dysmetria with videos and also use the videos to demonstrate and characterize the features of the dysmetria. Interestingly, the characteristics of the dysmetria appear to be different from those seen in patients with dysmetria arising from a cerebellar or thalamic lesion. We discuss the likely neurophysiologic mechanisms responsible for the condition and recovery. Simple noninvasive study of patients with ataxia and dysmetria secondary to a pontine lacunar infarct may be most helpful in elucidating the contribution of pontocerebellar fibers to motor control. V. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  3. Embodied cognition and the cerebellum: Perspectives from the Dysmetria of Thought and the Universal Cerebellar Transform theories.

    PubMed

    Guell, Xavier; Gabrieli, John D E; Schmahmann, Jeremy D

    2018-03-01

    In this report, we analyze the relationship between embodied cognition and current theories of the cerebellum, particularly the Dysmetria of Thought theory and the concept of the Universal Cerebellar Transform (UCT). First, we describe the UCT and the Dysmetria of Thought theories, highlight evidence supporting these hypotheses and discuss their mechanisms, functions and relevance. We then propose the following relationships. (i) The UCT strengthens embodied cognition because it provides an example of embodiment where the nature and intensity of the dependence between cognitive, affective and sensorimotor processes are defined. (ii) Conversely, embodied cognition bolsters the UCT theory because it contextualizes a cerebellum-focused theory within a general neurological theory. (iii) Embodied cognition supports the extension to other brain regions of the principles of organization of cerebral cortical connections that underlie the UCT: The notion that cytoarchitectonically determined transforms manifest via connectivity as sensorimotor, cognitive and affective functions resonates with the embodiment thesis that cognitive, affective and sensorimotor systems are interdependent. (iv) Embodied cognition might shape future definitions of the UCT because embodiment redefines the relationship between the neurological systems modulated by the UCT. We conclude by analyzing the relationship between our hypotheses and the concept of syntax and action semantics deficits in motor diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Preliminary pilot fMRI study of neuropostural optimization with a noninvasive asymmetric radioelectric brain stimulation protocol in functional dysmetria

    PubMed Central

    Mura, Marco; Castagna, Alessandro; Fontani, Vania; Rinaldi, Salvatore

    2012-01-01

    Purpose This study assessed changes in functional dysmetria (FD) and in brain activation observable by functional magnetic resonance imaging (fMRI) during a leg flexion-extension motor task following brain stimulation with a single radioelectric asymmetric conveyer (REAC) pulse, according to the precisely defined neuropostural optimization (NPO) protocol. Population and methods Ten healthy volunteers were assessed using fMRI conducted during a simple motor task before and immediately after delivery of a single REAC-NPO pulse. The motor task consisted of a flexion-extension movement of the legs with the knees bent. FD signs and brain activation patterns were compared before and after REAC-NPO. Results A single 250-millisecond REAC-NPO treatment alleviated FD, as evidenced by patellar asymmetry during a sit-up motion, and modulated activity patterns in the brain, particularly in the cerebellum, during the performance of the motor task. Conclusion Activity in brain areas involved in motor control and coordination, including the cerebellum, is altered by administration of a REAC-NPO treatment and this effect is accompanied by an alleviation of FD. PMID:22536071

  5. Experimental evidence of a pathogen invasion threshold

    PubMed Central

    Krkošek, Martin

    2018-01-01

    Host density thresholds to pathogen invasion separate regions of parameter space corresponding to endemic and disease-free states. The host density threshold is a central concept in theoretical epidemiology and a common target of human and wildlife disease control programmes, but there is mixed evidence supporting the existence of thresholds, especially in wildlife populations or for pathogens with complex transmission modes (e.g. environmental transmission). Here, we demonstrate the existence of a host density threshold for an environmentally transmitted pathogen by combining an epidemiological model with a microcosm experiment. Experimental epidemics consisted of replicate populations of naive crustacean zooplankton (Daphnia dentifera) hosts across a range of host densities (20–640 hosts l−1) that were exposed to an environmentally transmitted fungal pathogen (Metschnikowia bicuspidata). Epidemiological model simulations, parametrized independently of the experiment, qualitatively predicted experimental pathogen invasion thresholds. Variability in parameter estimates did not strongly influence outcomes, though systematic changes to key parameters have the potential to shift pathogen invasion thresholds. In summary, we provide one of the first clear experimental demonstrations of pathogen invasion thresholds in a replicated experimental system, and provide evidence that such thresholds may be predictable using independently constructed epidemiological models. PMID:29410876

  6. Theoretical and Experimental Evidence for a Nodal Energy Gap in MgB2

    DTIC Science & Technology

    2017-02-17

    1   Theoretical and Experimental Evidence for a Nodal Energy Gap in MgB2 Y. Dan Agassia and Daniel E. Oatesb aConsultant, Jerusalem, Israel bMIT...surface impedance and intermodulation distortion in high-quality thin films. We briefly review experimental evidence in support of our hypothesis and...demonstrates, this experimental evidence agrees with the l = 6 hypothesis, while inconsistent with s-wave symmetry. To give the l = 6 hypothesis a

  7. Experimental Evidence for LENR in a Polarized Pd/D Lattice

    NASA Astrophysics Data System (ADS)

    Szpak, S.

    2005-03-01

    Experimental evidence in support of claims that excess enthalpy production in a polarized Pd/D lattice is of a nuclear origin is questioned on various grounds, eg marginal intensity and difficulty in reproducing. Here, evidence is presented that is 100% reproducible and of sufficient intensity to be well outside of experimental errors. In addition to the thermal behavior, the nuclear manifestations include: X-ray emission; tritium production; and, when an operating cell is placed in an external electric field, fusion to create heavier metals such as Ca, Al, Mg, and Zn.

  8. Experimental evidence for herbivore limitation of the treeline.

    PubMed

    Speed, James D M; Austrheim, Gunnar; Hester, Alison J; Mysterud, Atle

    2010-11-01

    The treeline ecotone divides forest from open alpine or arctic vegetation states. Treelines are generally perceived to be temperature limited. The role of herbivores in limiting the treeline is more controversial, as experimental evidence from relevant large scales is lacking. Here we quantify the impact of different experimentally controlled herbivore densities on the recruitment and survival of birch Betula pubescens tortuosa along an altitudinal gradient in the mountains of southern Norway. After eight years of summer grazing in large-scale enclosures at densities of 0, 25, and 80 sheep/km2, birch recruited within the whole altitudinal range of ungrazed enclosures, but recruitment was rarer in enclosures with low-density sheep and was largely limited to within the treeline in enclosures with high-density sheep. In contrast, the distribution of saplings (birch older than the experiment) did not differ between grazing treatments, suggesting that grazing sheep primarily limit the establishment of new tree recruits rather than decrease the survival of existing individuals. This study provides direct experimental evidence that herbivores can limit the treeline below its potential at the landscape scale and even at low herbivore densities in this climatic zone. Land use changes should thus be considered in addition to climatic changes as potential drivers of ecotone shifts.

  9. Single-Subject Experimental Design for Evidence-Based Practice

    ERIC Educational Resources Information Center

    Byiers, Breanne J.; Reichle, Joe; Symons, Frank J.

    2012-01-01

    Purpose: Single-subject experimental designs (SSEDs) represent an important tool in the development and implementation of evidence-based practice in communication sciences and disorders. The purpose of this article is to review the strategies and tactics of SSEDs and their application in speech-language pathology research. Method: The authors…

  10. Experimental Evidence of Dipolar Interaction in Bilayer Nanocomposite Magnets

    DTIC Science & Technology

    2010-11-25

    corporated to improve experimental systems. However, re- ported bulk nanocomposite magnets exhibit (BH)max val- ues that are far below the...Appl Phys A DOI 10.1007/s00339-010-6073-6 Experimental evidence of dipolar interaction in bilayer nanocomposite magnets A.J. Zambano · H. Oguchi · I...Abstract We use magnetic thin film hard/non/soft-mag- netic trilayer systems to probe the nature of the hard–soft phase interaction and the role

  11. The experimental evidence for parapsychological phenomena: A review.

    PubMed

    Cardeña, Etzel

    2018-05-24

    This article presents a comprehensive integration of current experimental evidence and theories about so-called parapsychological (psi) phenomena. Throughout history, people have reported events that seem to violate the common sense view of space and time. Some psychologists have been at the forefront of investigating these phenomena with sophisticated research protocols and theory, while others have devoted much of their careers to criticizing the field. Both stances can be explained by psychologists' expertise on relevant processes such as perception, memory, belief, and conscious and nonconscious processes. This article clarifies the domain of psi, summarizes recent theories from physics and psychology that present psi phenomena as at least plausible, and then provides an overview of recent/updated meta-analyses. The evidence provides cumulative support for the reality of psi, which cannot be readily explained away by the quality of the studies, fraud, selective reporting, experimental or analytical incompetence, or other frequent criticisms. The evidence for psi is comparable to that for established phenomena in psychology and other disciplines, although there is no consensual understanding of them. The article concludes with recommendations for further progress in the field including the use of project and data repositories, conducting multidisciplinary studies with enough power, developing further nonconscious measures of psi and falsifiable theories, analyzing the characteristics of successful sessions and participants, improving the ecological validity of studies, testing how to increase effect sizes, recruiting more researchers at least open to the possibility of psi, and situating psi phenomena within larger domains such as the study of consciousness. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  12. Cycle frequency in standard Rock-Paper-Scissors games: Evidence from experimental economics

    NASA Astrophysics Data System (ADS)

    Xu, Bin; Zhou, Hai-Jun; Wang, Zhijian

    2013-10-01

    The Rock-Paper-Scissors (RPS) game is a widely used model system in game theory. Evolutionary game theory predicts the existence of persistent cycles in the evolutionary trajectories of the RPS game, but experimental evidence has remained to be rather weak. In this work, we performed laboratory experiments on the RPS game and analyzed the social-state evolutionary trajectories of twelve populations of N=6 players. We found strong evidence supporting the existence of persistent cycles. The mean cycling frequency was measured to be 0.029±0.009 period per experimental round. Our experimental observations can be quantitatively explained by a simple non-equilibrium model, namely the discrete-time logit dynamical process with a noise parameter. Our work therefore favors the evolutionary game theory over the classical game theory for describing the dynamical behavior of the RPS game.

  13. The Development of Experimentation and Evidence Evaluation Skills at Preschool Age

    NASA Astrophysics Data System (ADS)

    Piekny, Jeanette; Grube, Dietmar; Maehler, Claudia

    2014-01-01

    Researchers taking a domain-general approach to the development of scientific reasoning long thought that the ability to engage in scientific reasoning did not develop until adolescence. However, more recent studies have shown that preschool children already have a basic ability to evaluate evidence and a basic understanding of experimentation. Data providing insights into when exactly in the preschool years significant gains in these abilities occur are scarce. Drawing on a sample of 138 preschool children, this longitudinal study therefore examined how children's ability to evaluate evidence and their understanding of experimentation develop between the ages of four and six. Findings showed that the ability to evaluate evidence was already well developed at age four and increased steadily and significantly over time as long as the pattern of covariation was perfect. In the case of imperfect covariation, the proportion of correct answers was low over the period of observation, but showed a significant increase between the ages of four and five. If the data did not allow relationship between variables to be inferred, the proportion of correct answers was low, with a significant increase between the ages of five and six. The children's understanding of experimentation increased significantly between the ages of five and six. The implications of these findings for age-appropriate science programs in preschool are discussed.

  14. Early-Life Nutritional Programming of Type 2 Diabetes: Experimental and Quasi-Experimental Evidence.

    PubMed

    Vaiserman, Alexander M

    2017-03-05

    Consistent evidence from both experimental and human studies suggest that inadequate nutrition in early life can contribute to risk of developing metabolic disorders including type 2 diabetes (T2D) in adult life. In human populations, most findings supporting a causative relationship between early-life malnutrition and subsequent risk of T2D were obtained from quasi-experimental studies ('natural experiments'). Prenatal and/or early postnatal exposures to famine were demonstrated to be associated with higher risk of T2D in many cohorts around the world. Recent studies have highlighted the importance of epigenetic regulation of gene expression as a possible major contributor to the link between the early-life famine exposure and T2D in adulthood. Findings from these studies suggest that prenatal exposure to the famine may result in induction of persistent epigenetic changes that have adaptive significance in postnatal development but can predispose to metabolic disorders including T2D at the late stages of life. In this review, quasi-experimental data on the developmental programming of T2D are summarized and recent research findings on changes in DNA methylation that mediate these effects are discussed.

  15. Early-Life Nutritional Programming of Type 2 Diabetes: Experimental and Quasi-Experimental Evidence

    PubMed Central

    Vaiserman, Alexander M.

    2017-01-01

    Consistent evidence from both experimental and human studies suggest that inadequate nutrition in early life can contribute to risk of developing metabolic disorders including type 2 diabetes (T2D) in adult life. In human populations, most findings supporting a causative relationship between early-life malnutrition and subsequent risk of T2D were obtained from quasi-experimental studies (‘natural experiments’). Prenatal and/or early postnatal exposures to famine were demonstrated to be associated with higher risk of T2D in many cohorts around the world. Recent studies have highlighted the importance of epigenetic regulation of gene expression as a possible major contributor to the link between the early-life famine exposure and T2D in adulthood. Findings from these studies suggest that prenatal exposure to the famine may result in induction of persistent epigenetic changes that have adaptive significance in postnatal development but can predispose to metabolic disorders including T2D at the late stages of life. In this review, quasi-experimental data on the developmental programming of T2D are summarized and recent research findings on changes in DNA methylation that mediate these effects are discussed. PMID:28273874

  16. Computational neurobiology is a useful tool in translational neurology: the example of ataxia

    PubMed Central

    Brown, Sherry-Ann; McCullough, Louise D.; Loew, Leslie M.

    2014-01-01

    Hereditary ataxia, or motor incoordination, affects approximately 150,000 Americans and hundreds of thousands of individuals worldwide with onset from as early as mid-childhood. Affected individuals exhibit dysarthria, dysmetria, action tremor, and diadochokinesia. In this review, we consider an array of computational studies derived from experimental observations relevant to human neuropathology. A survey of related studies illustrates the impact of integrating clinical evidence with data from mouse models and computational simulations. Results from these studies may help explain findings in mice, and after extensive laboratory study, may ultimately be translated to ataxic individuals. This inquiry lays a foundation for using computation to understand neurobiochemical and electrophysiological pathophysiology of spinocerebellar ataxias and may contribute to development of therapeutics. The interdisciplinary analysis suggests that computational neurobiology can be an important tool for translational neurology. PMID:25653585

  17. A Review of Experimental Evidence Linking Neurotoxic Organophosphorus Compounds and Inflammation

    PubMed Central

    Banks, Christopher N.; Lein, Pamela J.

    2012-01-01

    Organophosphorus (OP) nerve agents and pesticides inhibit acetylcholinesterase (AChE), and this is thought to be a primary mechanism mediating the neurotoxicity of these compounds. However, a number of observations suggest that mechanisms other than or in addition to AChE inhibition contribute to OP neurotoxicity. There is significant experimental evidence that acute OP intoxication elicits a robust inflammatory response, and emerging evidence suggests that chronic repeated low-level OP exposure also upregulates inflammatory mediators. A critical question that is just beginning to be addressed experimentally is the pathophysiologic relevance of inflammation in either acute or chronic OP intoxication. The goal of this article is to provide a brief review of the current status of our knowledge linking inflammation to OP intoxication, and to discuss the implications of these findings in the context of therapeutic and diagnostic approaches to OP neurotoxicity. PMID:22342984

  18. Teacher Incentives in Developing Countries: Experimental Evidence from India. Research Brief

    ERIC Educational Resources Information Center

    National Center on Performance Incentives, 2008

    2008-01-01

    In "Teacher Incentives in Developing Countries: Experimental Evidence from India"--a paper presented at the National Center on Performance Incentives research to policy conference in February--Karthik Muralidharan (Harvard University) and Venkatesh Sundararaman (The World Bank) present findings from a randomized experiment conducted in…

  19. Evidence for chaos in an experimental time series from serrated plastic flow

    NASA Astrophysics Data System (ADS)

    Venkadesan, S.; Valsakumar, M. C.; Murthy, K. P. N.; Rajasekar, S.

    1996-07-01

    An experimental time series from a tensile test of an Al-Mg alloy in the serrated plastic flow domain is analyzed for signature of chaos. We employ state space reconstruction by embedding of time delay vectors. The minimum embedding dimension is found to be 4 and the largest Lyapunov exponent is positive, thereby providing prima facie evidence for chaos in an experimental time series of serrated plastic flow data.

  20. How experimental biology and ecology can support evidence-based decision-making in conservation: avoiding pitfalls and enabling application.

    PubMed

    Cooke, Steven J; Birnie-Gauvin, Kim; Lennox, Robert J; Taylor, Jessica J; Rytwinski, Trina; Rummer, Jodie L; Franklin, Craig E; Bennett, Joseph R; Haddaway, Neal R

    2017-01-01

    Policy development and management decisions should be based upon the best available evidence. In recent years, approaches to evidence synthesis, originating in the medical realm (such as systematic reviews), have been applied to conservation to promote evidence-based conservation and environmental management. Systematic reviews involve a critical appraisal of evidence, but studies that lack the necessary rigour (e.g. experimental, technical and analytical aspects) to justify their conclusions are typically excluded from systematic reviews or down-weighted in terms of their influence. One of the strengths of conservation physiology is the reliance on experimental approaches that help to more clearly establish cause-and-effect relationships. Indeed, experimental biology and ecology have much to offer in terms of building the evidence base that is needed to inform policy and management options related to pressing issues such as enacting endangered species recovery plans or evaluating the effectiveness of conservation interventions. Here, we identify a number of pitfalls that can prevent experimental findings from being relevant to conservation or would lead to their exclusion or down-weighting during critical appraisal in a systematic review. We conclude that conservation physiology is well positioned to support evidence-based conservation, provided that experimental designs are robust and that conservation physiologists understand the nuances associated with informing decision-making processes so that they can be more relevant.

  1. How experimental biology and ecology can support evidence-based decision-making in conservation: avoiding pitfalls and enabling application

    PubMed Central

    Birnie-Gauvin, Kim; Lennox, Robert J.; Taylor, Jessica J.; Rytwinski, Trina; Rummer, Jodie L.; Franklin, Craig E.; Bennett, Joseph R.; Haddaway, Neal R.

    2017-01-01

    Abstract Policy development and management decisions should be based upon the best available evidence. In recent years, approaches to evidence synthesis, originating in the medical realm (such as systematic reviews), have been applied to conservation to promote evidence-based conservation and environmental management. Systematic reviews involve a critical appraisal of evidence, but studies that lack the necessary rigour (e.g. experimental, technical and analytical aspects) to justify their conclusions are typically excluded from systematic reviews or down-weighted in terms of their influence. One of the strengths of conservation physiology is the reliance on experimental approaches that help to more clearly establish cause-and-effect relationships. Indeed, experimental biology and ecology have much to offer in terms of building the evidence base that is needed to inform policy and management options related to pressing issues such as enacting endangered species recovery plans or evaluating the effectiveness of conservation interventions. Here, we identify a number of pitfalls that can prevent experimental findings from being relevant to conservation or would lead to their exclusion or down-weighting during critical appraisal in a systematic review. We conclude that conservation physiology is well positioned to support evidence-based conservation, provided that experimental designs are robust and that conservation physiologists understand the nuances associated with informing decision-making processes so that they can be more relevant. PMID:28835842

  2. Experimental Evidence on Iterated Reasoning in Games

    PubMed Central

    Grehl, Sascha; Tutić, Andreas

    2015-01-01

    We present experimental evidence on two forms of iterated reasoning in games, i.e. backward induction and interactive knowledge. Besides reliable estimates of the cognitive skills of the subjects, our design allows us to disentangle two possible explanations for the observed limits in performed iterated reasoning: Restrictions in subjects’ cognitive abilities and their beliefs concerning the rationality of co-players. In comparison to previous literature, our estimates regarding subjects’ skills in iterated reasoning are quite pessimistic. Also, we find that beliefs concerning the rationality of co-players are completely irrelevant in explaining the observed limited amount of iterated reasoning in the dirty faces game. In addition, it is demonstrated that skills in backward induction are a solid predictor for skills in iterated knowledge, which points to some generalized ability of the subjects in iterated reasoning. PMID:26312486

  3. Experimental evidence of a symbiosis between red-cockaded woodpeckers and fungi.

    PubMed

    Jusino, Michelle A; Lindner, Daniel L; Banik, Mark T; Rose, Kevin R; Walters, Jeffrey R

    2016-03-30

    Primary cavity excavators, such as woodpeckers, are ecosystem engineers in many systems. Associations between cavity excavators and fungi have long been hypothesized to facilitate cavity excavation, but these relationships have not been experimentally verified. Fungi may help excavators by softening wood, while excavators may facilitate fungal dispersal. Here we demonstrate that excavators facilitate fungal dispersal and thus we report the first experimental evidence of a symbiosis between fungi and a cavity excavator, the red-cockaded woodpecker (RCW,Picoides borealis). Swab samples of birds showed that RCWs carry fungal communities similar to those found in their completed excavations. A 26-month field experiment using human-made aseptically drilled excavations in live trees, half of which were inaccessible to RCWs, demonstrated that RCWs directly alter fungal colonization and community composition. Experimental excavations that were accessible to RCWs contained fungal communities similar to natural RCW excavations, whereas inaccessible experimental excavations contained significantly different fungal communities. Our work demonstrates a complex symbiosis between cavity excavators and communities of fungi, with implications for forest ecology, wildlife management, and conservation. © 2016 The Author(s).

  4. Experimental evidence of body centered cubic iron in Earth's core

    NASA Astrophysics Data System (ADS)

    Hrubiak, R.; Meng, Y.; Shen, G.

    2017-12-01

    The Earth's core is mainly composed of iron. While seismic evidence has shown a liquid outer core and a solid inner core, the crystalline nature of the solid iron at the core condition remains debated, largely due to the difficulties in experimental determination of exact polymorphs at corresponding pressure-temperature conditions. We have examined crystal structures of iron up to 220 GPa and 6000 K with x-ray diffraction using a double-sided laser heating system at HPCAT, Advanced Photon Source. The iron sample is confined in a small chamber surrounded by single crystal MgO. The laser power can be modulated together with temperature measurements. The modulated heating of iron in an MgO single crystal matrix allows for microstructure analysis during heating and after the sample is quenched. We present experimental evidence of a body-centered-cubic (BCC) iron from about 100 GPa and 3000 K to at least 220 GPa and 4000 K. The observed BCC phase may be consistent with a theoretically predicted BCC phase that is dynamically stable in similar pressure-temperature conditions [1]. We will discuss the stability region of the BCC phase and the melting curve of iron and their implications in the nature of the Earth's inner core. References: A. B. Belonoshko et al., Nat. Geosci., 1-6 (2017).

  5. Quasi-experimental study designs series-paper 12: strengthening global capacity for evidence synthesis of quasi-experimental health systems research.

    PubMed

    Rockers, Peter C; Tugwell, Peter; Grimshaw, Jeremy; Oliver, Sandy; Atun, Rifat; Røttingen, John-Arne; Fretheim, Atle; Ranson, M Kent; Daniels, Karen; Luiza, Vera Lucia; Bärnighausen, Till

    2017-09-01

    Evidence from quasi-experimental studies is often excluded from systematic reviews of health systems research despite the fact that such studies can provide strong causal evidence when well conducted. This article discusses global coordination of efforts to institutionalize the inclusion of causal evidence from quasi-experiments in systematic reviews of health systems research. In particular, we are concerned with identifying opportunities for strengthening capacity at the global and local level for implementing protocols necessary to ensure that reviews that include quasi-experiments are consistently of the highest quality. We first describe the current state of the global infrastructure that facilitates the production of systematic reviews of health systems research. We identify five important types of actors operating within this infrastructure: review authors; synthesis collaborations that facilitate the review process; synthesis interest groups that supplement the work of the larger collaborations; review funders; and end users, including policymakers. Then, we examine opportunities for intervening to build the capacity of each type of actors to support the inclusion of quasi-experiments in reviews. Finally, we suggest practical next steps for proceeding with capacity building efforts. Because of the complexity and relative nascence of the field, we recommend a carefully planned and executed approach to strengthening global capacity for the inclusion of quasi-experimental studies in systematic reviews. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Experimental evidence for inherent Lévy search behaviour in foraging animals.

    PubMed

    Kölzsch, Andrea; Alzate, Adriana; Bartumeus, Frederic; de Jager, Monique; Weerman, Ellen J; Hengeveld, Geerten M; Naguib, Marc; Nolet, Bart A; van de Koppel, Johan

    2015-05-22

    Recently, Lévy walks have been put forward as a new paradigm for animal search and many cases have been made for its presence in nature. However, it remains debated whether Lévy walks are an inherent behavioural strategy or emerge from the animal reacting to its habitat. Here, we demonstrate signatures of Lévy behaviour in the search movement of mud snails (Hydrobia ulvae) based on a novel, direct assessment of movement properties in an experimental set-up using different food distributions. Our experimental data uncovered clusters of small movement steps alternating with long moves independent of food encounter and landscape complexity. Moreover, size distributions of these clusters followed truncated power laws. These two findings are characteristic signatures of mechanisms underlying inherent Lévy-like movement. Thus, our study provides clear experimental evidence that such multi-scale movement is an inherent behaviour rather than resulting from the animal interacting with its environment. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  7. Experimental evidence for inherent Lévy search behaviour in foraging animals

    PubMed Central

    Kölzsch, Andrea; Alzate, Adriana; Bartumeus, Frederic; de Jager, Monique; Weerman, Ellen J.; Hengeveld, Geerten M.; Naguib, Marc; Nolet, Bart A.; van de Koppel, Johan

    2015-01-01

    Recently, Lévy walks have been put forward as a new paradigm for animal search and many cases have been made for its presence in nature. However, it remains debated whether Lévy walks are an inherent behavioural strategy or emerge from the animal reacting to its habitat. Here, we demonstrate signatures of Lévy behaviour in the search movement of mud snails (Hydrobia ulvae) based on a novel, direct assessment of movement properties in an experimental set-up using different food distributions. Our experimental data uncovered clusters of small movement steps alternating with long moves independent of food encounter and landscape complexity. Moreover, size distributions of these clusters followed truncated power laws. These two findings are characteristic signatures of mechanisms underlying inherent Lévy-like movement. Thus, our study provides clear experimental evidence that such multi-scale movement is an inherent behaviour rather than resulting from the animal interacting with its environment. PMID:25904671

  8. Experimental evidence for homeostatic sex allocation after sex-biased reintroductions.

    PubMed

    Linklater, Wayne Leslie; Law, Peter Roy; Gedir, Jay Vinson; du Preez, Pierre

    2017-03-06

    First principles predict negative frequency-dependent sex allocation, but it is unproven in field studies and seldom considered, despite far-reaching consequences for theory and practice in population genetics and dynamics as well as animal ecology and behaviour. Twenty-four years of rhinoceros calving after 45 reintroductions across southern Africa provide the first in situ experimental evidence that unbalanced operational sex ratios predicted offspring sex and offspring sex ratios. Our understanding of population dynamics, especially reintroduction and invasion biology, will be significantly impacted by these findings.

  9. Neurological soft signs feature a double dissociation within the language system in Williams syndrome.

    PubMed

    Tavano, Alessandro; Gagliardi, Chiara; Martelli, Sara; Borgatti, Renato

    2010-09-01

    The neurocognitive profile of Williams-Beuren syndrome (WBS) is characterized by visuospatial deficits, apparently fluent language, motor soft signs, and hypersociability. We investigated the association between neuromotor soft signs and visuospatial, executive-attentive, mnestic and linguistic functions in a group of 26 children and young adults with WBS. We hypothesized that neurological soft signs could be an index of subtle neurofunctional deficits and thus provide a behavioural window into the processes underlying neurocognition in Williams-Beuren syndrome. Dysmetria and dystonic movements were selected as grouping neurological variables, indexing cerebellar and basal ganglia dysfunction, respectively. No detrimental effects on visuospatial/visuoconstructive skills were evident following the presence of either neurological variable. As for language skills, participants with dysmetria showed markedly reduced expressive syntactic and lexico-semantic skills as compared to non-affected individuals, while no difference in chronological age was evident. Participants with dystonic movements showed reduced receptive syntax and increased lexical comprehension skills as compared to non-affected individuals, the age factor being significant. In both instances, the effect size was greater for syntactic measures. We take these novel findings as suggestive of a double dissociation between expressive and receptive skills at sentence level within the WBS linguistic phenotype. The investigation of neuromotor soft signs and neuropsychological functions may provide a key to new non-cortico-centric genotype/phenotype relationships. Copyright 2010 Elsevier Ltd. All rights reserved.

  10. Experimental evidence on microwave induced electron losses from ECRIS plasma

    NASA Astrophysics Data System (ADS)

    Sakildien, M.; Tarvainen, O.; Kronholm, R.; Izotov, I.; Skalyga, V.; Kalvas, T.; Jones, P.; Koivisto, H.

    2018-06-01

    The balance between warm and hot (>1 keV) electron density and their losses from the magnetic confinement system of an Electron Cyclotron Resonance Ion Source (ECRIS) plasma is considered to be one of the main factors determining the rate of the high charge state ion production. One of the key loss channels for heated electrons is thought to be induced by the injected microwaves. While this loss mechanism, referred to as rf-induced pitch angle scattering, has been studied theoretically and with computational tools, direct experimental evidence of its significance in minimum-B ECRIS plasmas remains limited. In this work, experimental evidence of microwave induced electron losses in the axial direction is presented in both continuous wave (CW) and pulsed operation of a 14 GHz ECRIS. In the CW mode, the experiment was carried out by comparing the characteristic X-ray emission from the plasma volume and from the surface of the biased disc located in the flux of the escaping electron at the axial magnetic mirror. Parametric sweeps of magnetic field, neutral gas pressure, and microwave power were conducted to determine their effect on electron losses. In the pulsed mode, the experiment was conducted by measuring the flux of escaping electrons through aluminum foils of different thicknesses providing some energy resolution. Both diagnostics support the view that rf-induced losses account for up to 70% of total hot electron losses and their importance depends on the source parameters, especially power and neutral gas pressure.

  11. Experimental evidence that parasites drive eco-evolutionary feedbacks.

    PubMed

    Brunner, Franziska S; Anaya-Rojas, Jaime M; Matthews, Blake; Eizaguirre, Christophe

    2017-04-04

    Host resistance to parasites is a rapidly evolving trait that can influence how hosts modify ecosystems. Eco-evolutionary feedbacks may develop if the ecosystem effects of host resistance influence selection on subsequent host generations. In a mesocosm experiment, using a recently diverged (<100 generations) pair of lake and stream three-spined sticklebacks, we tested how experimental exposure to a common fish parasite ( Gyrodactylus spp.) affects interactions between hosts and their ecosystems in two environmental conditions (low and high nutrients). In both environments, we found that stream sticklebacks were more resistant to Gyrodactylus and had different gene expression profiles than lake sticklebacks. This differential infection led to contrasting effects of sticklebacks on a broad range of ecosystem properties, including zooplankton community structure and nutrient cycling. These ecosystem modifications affected the survival, body condition, and gene expression profiles of a subsequent fish generation. In particular, lake juvenile fish suffered increased mortality in ecosystems previously modified by lake adults, whereas stream fish showed decreased body condition in stream fish-modified ecosystems. Parasites reinforced selection against lake juveniles in lake fish-modified ecosystems, but only under oligotrophic conditions. Overall, our results highlight the overlapping timescales and the interplay of host-parasite and host-ecosystem interactions. We provide experimental evidence that parasites influence host-mediated effects on ecosystems and, thereby, change the likelihood and strength of eco-evolutionary feedbacks.

  12. Experimental evidence that parasites drive eco-evolutionary feedbacks

    PubMed Central

    Brunner, Franziska S.; Anaya-Rojas, Jaime M.; Matthews, Blake; Eizaguirre, Christophe

    2017-01-01

    Host resistance to parasites is a rapidly evolving trait that can influence how hosts modify ecosystems. Eco-evolutionary feedbacks may develop if the ecosystem effects of host resistance influence selection on subsequent host generations. In a mesocosm experiment, using a recently diverged (<100 generations) pair of lake and stream three-spined sticklebacks, we tested how experimental exposure to a common fish parasite (Gyrodactylus spp.) affects interactions between hosts and their ecosystems in two environmental conditions (low and high nutrients). In both environments, we found that stream sticklebacks were more resistant to Gyrodactylus and had different gene expression profiles than lake sticklebacks. This differential infection led to contrasting effects of sticklebacks on a broad range of ecosystem properties, including zooplankton community structure and nutrient cycling. These ecosystem modifications affected the survival, body condition, and gene expression profiles of a subsequent fish generation. In particular, lake juvenile fish suffered increased mortality in ecosystems previously modified by lake adults, whereas stream fish showed decreased body condition in stream fish-modified ecosystems. Parasites reinforced selection against lake juveniles in lake fish-modified ecosystems, but only under oligotrophic conditions. Overall, our results highlight the overlapping timescales and the interplay of host–parasite and host–ecosystem interactions. We provide experimental evidence that parasites influence host-mediated effects on ecosystems and, thereby, change the likelihood and strength of eco-evolutionary feedbacks. PMID:28320947

  13. Eye movement abnormalities in essential tremor

    PubMed Central

    Plinta, Klaudia; Krzak-Kubica, Agnieszka; Zajdel, Katarzyna; Falkiewicz, Marcel; Dylak, Jacek; Ober, Jan; Szczudlik, Andrzej; Rudzińska, Monika

    2016-01-01

    Abstract Essential tremor (ET) is the most prevalent movement disorder, characterized mainly by an action tremor of the arms. Only a few studies published as yet have assessed oculomotor abnormalities in ET and their results are unequivocal. The aim of this study was to assess the oculomotor abnormalities in ET patients compared with the control group and to find the relationship between oculomotor abnormalities and clinical features of ET patients. We studied 50 ET patients and 42 matched by age and gender healthy controls. Saccadometer Advanced (Ober Consulting, Poland) was used to investigate reflexive, pace-induced and cued saccades and conventional electrooculography for evaluation of smooth pursuit and fixation. The severity of the tremor was assessed by the Clinical Rating Scale for Tremor. Significant differences between ET patients and controls were found for the incidence of reflexive saccades dysmetria and deficit of smooth pursuit. Reflexive saccades dysmetria was more frequent in patients in the second and third phase of ET compared to the first phase. The reflexive saccades latency increase was correlated with severity of the tremor. In conclusion, oculomotor abnormalities were significantly more common in ET patients than in healthy subjects. The most common oculomotor disturbances in ET were reflexive saccades dysmetria and slowing of smooth pursuit. The frequency of reflexive saccades dysmetria increased with progression of ET. The reflexive saccades latency increase was related to the severity of tremor. PMID:28149393

  14. Experimental evidence of hourglass fermion in the candidate nonsymmorphic topological insulator KHgSb

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ma, Junzhang; Yi, Changjiang; Lv, Baiqing

    Topological insulators (TIs) host novel states of quantum matter characterized by nontrivial conducting boundary states connecting valence and conduction bulk bands. All TIs discovered experimentally so far rely on either time-reversal or mirror crystal symmorphic symmetry to protect massless Dirac-like boundary states. Several materials were recently proposed to be TIs with nonsymmorphic symmetry, where a glide mirror protects exotic surface fermions with hourglass-shaped dispersion. However, an experimental confirmation of this new fermion is missing. Using angle-resolved photoemission spectroscopy, we provide experimental evidence of hourglass fermions on the (010) surface of crystalline KHgSb, whereas the (001) surface has no boundary state,more » in agreement with first-principles calculations. Our study will stimulate further research activities of topological properties of nonsymmorphic materials.« less

  15. Experimental evidence of hourglass fermion in the candidate nonsymmorphic topological insulator KHgSb

    DOE PAGES

    Ma, Junzhang; Yi, Changjiang; Lv, Baiqing; ...

    2017-05-05

    Topological insulators (TIs) host novel states of quantum matter characterized by nontrivial conducting boundary states connecting valence and conduction bulk bands. All TIs discovered experimentally so far rely on either time-reversal or mirror crystal symmorphic symmetry to protect massless Dirac-like boundary states. Several materials were recently proposed to be TIs with nonsymmorphic symmetry, where a glide mirror protects exotic surface fermions with hourglass-shaped dispersion. However, an experimental confirmation of this new fermion is missing. Using angle-resolved photoemission spectroscopy, we provide experimental evidence of hourglass fermions on the (010) surface of crystalline KHgSb, whereas the (001) surface has no boundary state,more » in agreement with first-principles calculations. Our study will stimulate further research activities of topological properties of nonsymmorphic materials.« less

  16. Experimental evidence of rainfall driven knickpoints

    NASA Astrophysics Data System (ADS)

    Singh, A.; Tejedor, A.; Grimaud, J. L.; Foufoula-Georgiou, E.

    2017-12-01

    Formation of knickpoints is typically associated with a landscape's response to differential uplift causing a base-level fall that results in a steep region along a river's long profile. However, to the best of our knowledge, knickpoints have never been reported to form in landscapes subject to varying precipitation rate wherein uplift rate remains constant. Here we reveal evidence that knickpoints can indeed result from increasing precipitation rate, which reorganizes the production and delivery of sediment across a range of spatial and temporal scales, creating thus constraints and water-sediment flux disequilibria at local scales. We base our findings on analysis of high resolution topography data obtained from an experimental landscape conducted to study the effect of changing rainfall intensity on landscape evolution at short and long-time scales. Results from our study suggest that at the transient state of increasing precipitation, a scale-dependent behavior of erosion rates emerges that results in a regime shift in the transport processes in channels from supply-limited to sediment-flux dependent. This regime shift is caused by an increase in the sediment supply from the hillslopes, generating variability in water to sediment flux ratio (Qs/Qw) in channels of different sub-drainage basins which is further manifested in the longitudinal river profiles as abrupt changes in their gradients (knickpoints), advecting upstream on the river network as time proceeds.

  17. Experimental evidence for drought induced alternative stable states of soil moisture

    NASA Astrophysics Data System (ADS)

    Robinson, David. A.; Jones, Scott B.; Lebron, Inma; Reinsch, Sabine; Domínguez, María T.; Smith, Andrew R.; Jones, Davey L.; Marshall, Miles R.; Emmett, Bridget A.

    2016-01-01

    Ecosystems may exhibit alternative stable states (ASS) in response to environmental change. Modelling and observational data broadly support the theory of ASS, however evidence from manipulation experiments supporting this theory is limited. Here, we provide long-term manipulation and observation data supporting the existence of drought induced alternative stable soil moisture states (irreversible soil wetting) in upland Atlantic heath, dominated by Calluna vulgaris (L.) Hull. Manipulated repeated moderate summer drought, and intense natural summer drought both lowered resilience resulting in shifts in soil moisture dynamics. The repeated moderate summer drought decreased winter soil moisture retention by ~10%. However, intense summer drought, superimposed on the experiment, that began in 2003 and peaked in 2005 caused an unexpected erosion of resilience and a shift to an ASS; both for the experimental drought manipulation and control plots, impairing the soil from rewetting in winter. Measurements outside plots, with vegetation removal, showed no evidence of moisture shifts. Further independent evidence supports our findings from historical soil moisture monitoring at a long-term upland hydrological observatory. The results herald the need for a new paradigm regarding our understanding of soil structure, hydraulics and climate interaction.

  18. Experimental evidence for drought induced alternative stable states of soil moisture

    PubMed Central

    Robinson, David. A.; Jones, Scott B.; Lebron, Inma; Reinsch, Sabine; Domínguez, María T.; Smith, Andrew R.; Jones, Davey L.; Marshall, Miles R.; Emmett, Bridget A.

    2016-01-01

    Ecosystems may exhibit alternative stable states (ASS) in response to environmental change. Modelling and observational data broadly support the theory of ASS, however evidence from manipulation experiments supporting this theory is limited. Here, we provide long-term manipulation and observation data supporting the existence of drought induced alternative stable soil moisture states (irreversible soil wetting) in upland Atlantic heath, dominated by Calluna vulgaris (L.) Hull. Manipulated repeated moderate summer drought, and intense natural summer drought both lowered resilience resulting in shifts in soil moisture dynamics. The repeated moderate summer drought decreased winter soil moisture retention by ~10%. However, intense summer drought, superimposed on the experiment, that began in 2003 and peaked in 2005 caused an unexpected erosion of resilience and a shift to an ASS; both for the experimental drought manipulation and control plots, impairing the soil from rewetting in winter. Measurements outside plots, with vegetation removal, showed no evidence of moisture shifts. Further independent evidence supports our findings from historical soil moisture monitoring at a long-term upland hydrological observatory. The results herald the need for a new paradigm regarding our understanding of soil structure, hydraulics and climate interaction. PMID:26804897

  19. Experimental evidence of low-density liquid water upon rapid decompression

    PubMed Central

    Lin, Chuanlong; Smith, Jesse S.; Sinogeikin, Stanislav V.; Shen, Guoyin

    2018-01-01

    Water is an extraordinary liquid, having a number of anomalous properties which become strongly enhanced in the supercooled region. Due to rapid crystallization of supercooled water, there exists a region that has been experimentally inaccessible for studying deeply supercooled bulk water. Using a rapid decompression technique integrated with in situ X-ray diffraction, we show that a high-pressure ice phase transforms to a low-density noncrystalline (LDN) form upon rapid release of pressure at temperatures of 140–165 K. The LDN subsequently crystallizes into ice-Ic through a diffusion-controlled process. Together with the change in crystallization rate with temperature, the experimental evidence indicates that the LDN is a low-density liquid (LDL). The measured X-ray diffraction data show that the LDL is tetrahedrally coordinated with the tetrahedral network fully developed and clearly linked to low-density amorphous ices. On the other hand, there is a distinct difference in structure between the LDL and supercooled water or liquid water in terms of the tetrahedral order parameter. PMID:29440411

  20. Experimental evidence for a liquid-liquid crossover in deeply cooled confined water.

    PubMed

    Cupane, Antonio; Fomina, Margarita; Piazza, Irina; Peters, Judith; Schirò, Giorgio

    2014-11-21

    In this work we investigate, by means of elastic neutron scattering, the pressure dependence of mean square displacements (MSD) of hydrogen atoms of deeply cooled water confined in the pores of a three-dimensional disordered SiO2 xerogel; experiments have been performed at 250 and 210 K from atmospheric pressure to 1200 bar. The "pressure anomaly" of supercooled water (i.e., a mean square displacement increase with increasing pressure) is observed in our sample at both temperatures; however, contrary to previous simulation results and to the experimental trend observed in bulk water, the pressure effect is smaller at lower (210 K) than at higher (250 K) temperature. Elastic neutron scattering results are complemented by differential scanning calorimetry data that put in evidence, besides the glass transition at about 170 K, a first-order-like endothermic transition occurring at about 230 K that, in view of the neutron scattering results, can be attributed to a liquid-liquid crossover. Our results give experimental evidence for the presence, in deeply cooled confined water, of a crossover occurring at about 230 K (at ambient pressure) from a liquid phase predominant at 210 K to another liquid phase predominant at 250 K; therefore, they are fully consistent with the liquid-liquid transition hypothesis.

  1. Communicating Uncertain Experimental Evidence

    ERIC Educational Resources Information Center

    Davis, Alexander L.; Fischhoff, Baruch

    2014-01-01

    Four experiments examined when laypeople attribute unexpected experimental outcomes to error, in foresight and in hindsight, along with their judgments of whether the data should be published. Participants read vignettes describing hypothetical experiments, along with the result of the initial observation, considered as either a possibility…

  2. Experimental evidence of super-resolution better than λ/105 with positive refraction

    NASA Astrophysics Data System (ADS)

    Miñano, Juan C.; Sánchez-Dehesa, José; González, Juan C.; Benítez, P.; Grabovičkić, D.; Carbonell, Jorge; Ahmadpanahi, H.

    2014-03-01

    Super-resolution (SR) systems surpassing the Abbe diffraction limit have been theoretically and experimentally demonstrated using a number of different approaches and technologies: using materials with a negative refractive index, utilizing optical super-oscillation, using a resonant metalens, etc. However, recently it has been proved theoretically that in the Maxwell fish-eye lens (MFE), a device made of positive refractive index materials, the same phenomenon takes place. Moreover, using a simpler device equivalent to the MFE called the spherical geodesic waveguide (SGW), an SR of up to λ/3000 was simulated in COMSOL. Until now, only one piece of experimental evidence of SR with positive refraction has been reported (up to λ/5) for an MFE prototype working at microwave frequencies. Here, experimental results are presented for an SGW prototype showing an SR of up to λ/105. The SGW prototype consists of two concentric metallic spheres with an air space in between and two coaxial ports acting as an emitter and a receiver. The prototype has been analyzed in the range 1 GHz to 1.3 GHz.

  3. Evidence for distinct cognitive deficits after focal cerebellar lesions.

    PubMed

    Gottwald, B; Wilde, B; Mihajlovic, Z; Mehdorn, H M

    2004-11-01

    Anatomical evidence and lesion studies, as well as functional magnetic resonance imaging (fMRI) studies, indicate that the cerebellum contributes to higher cognitive functions. Cerebellar posterior lateral regions seem to be relevant for cognition, while vermal lesions seem to be associated with changes in affect. However, the results remain controversial. Deficits of patients are sometimes still attributed to motor impairment. We present data from a detailed neuropsychological examination of 21 patients with cerebellar lesions due to tumour or haematoma, and 21 controls matched for age, sex, and years of education. Patients showed deficits in executive function, and in attentional processes such as working memory and divided attention. Further analysis revealed that patients with right-sided lesions were in general more impaired than those with left-sided lesions. Those hypotheses that suggest that lesions of the right cerebellar hemisphere lead to verbal deficits, while those of the left lead to non-verbal deficits, have in part been confirmed. The generally greater impairment of those patients with a right-sided lesion has been interpreted as resulting from the connection of the right cerebellum to the left cerebral hemisphere, which is dominant for language functions and crucial for right hand movements. Motor impairment was correlated with less than half of the cognitive measures, with no stronger tendency for correlation with cognitive tests that require motor responses discernible. The results are discussed on the basis of an assumption that the cerebellum has a predicting and preparing function, indicating that cerebellar lesions lead to a "dysmetria of thought."

  4. Theory and experimental evidence of phonon domains and their roles in pre-martensitic phenomena

    NASA Astrophysics Data System (ADS)

    Jin, Yongmei M.; Wang, Yu U.; Ren, Yang

    2015-12-01

    Pre-martensitic phenomena, also called martensite precursor effects, have been known for decades while yet remain outstanding issues. This paper addresses pre-martensitic phenomena from new theoretical and experimental perspectives. A statistical mechanics-based Grüneisen-type phonon theory is developed. On the basis of deformation-dependent incompletely softened low-energy phonons, the theory predicts a lattice instability and pre-martensitic transition into elastic-phonon domains via 'phonon spinodal decomposition.' The phase transition lifts phonon degeneracy in cubic crystal and has a nature of phonon pseudo-Jahn-Teller lattice instability. The theory and notion of phonon domains consistently explain the ubiquitous pre-martensitic anomalies as natural consequences of incomplete phonon softening. The phonon domains are characterised by broken dynamic symmetry of lattice vibrations and deform through internal phonon relaxation in response to stress (a particular case of Le Chatelier's principle), leading to previously unexplored new domain phenomenon. Experimental evidence of phonon domains is obtained by in situ three-dimensional phonon diffuse scattering and Bragg reflection using high-energy synchrotron X-ray single-crystal diffraction, which observes exotic domain phenomenon fundamentally different from usual ferroelastic domain switching phenomenon. In light of the theory and experimental evidence of phonon domains and their roles in pre-martensitic phenomena, currently existing alternative opinions on martensitic precursor phenomena are revisited.

  5. Experimental Evidence for Wigner’s Tunneling Time

    NASA Astrophysics Data System (ADS)

    Camus, N.; Yakaboylu, E.; Fechner, L.; Klaiber, M.; Laux, M.; Mi, Y.; Hatsagortsyan, K. Z.; Pfeifer, T.; Keitel, C. H.; Moshammer, R.

    2018-04-01

    Tunneling of a particle through a barrier is one of the counter-intuitive properties of quantum mechanical motion. Thanks to advances in the generation of strong laser fields, new opportunities to dynamically investigate this process have been developed. In the so-called attoclock measurements the electron’s properties after tunneling are mapped on its emission direction. We investigate the tunneling dynamics and achieve a high sensitivity thanks to two refinements of the attoclock principle. Using near-IR wavelength we place firmly the ionization process in the tunneling regime. Furthermore, we compare the electron momentum distributions of two atomic species of slightly different atomic potentials (argon and krypton) being ionized under absolutely identical conditions. Experimentally, using a reaction microscope, we succeed in measuring the 3D electron momentum distributions for both targets simultaneously. Theoretically, the time resolved description of tunneling in strong-field ionization is studied using the leading quantum-mechanical Wigner treatment. A detailed analysis of the most probable photoelectron emission for Ar and Kr allows testing the theoretical models and a sensitive check of the electron initial conditions at the tunnel exit. The agreement between experiment and theory provides a clear evidence for a non-zero tunneling time delay and a non-vanishing longitudinal momentum at this point.

  6. Study types and reliability of Real World Evidence compared with experimental evidence used in Polish reimbursement decision-making processes.

    PubMed

    Wilk, N; Wierzbicka, N; Skrzekowska-Baran, I; Moćko, P; Tomassy, J; Kloc, K

    2017-04-01

    The aim of this study was to identify the relationship and impact between Real World Evidence (RWE) and experimental evidence (EE) in Polish decision-making processes for the drugs from selected Anatomical Therapeutic Chemical (ATC) groups. Descriptive study. A detailed analysis was performed for 58 processes from five ATC code groups in which RWE for effectiveness, or effectiveness and safety were cited in Agency for Health Technology Assessment and Tariff System's (AOTMiT) documents published between January 2012 and September 2015: Verification Analysis of AOTMiT, Statement of the Transparency Council of AOTMiT, and Recommendation of the President of AOTMiT. In 62% of the cases, RWE supported the EE and confirmed its main conclusions. The majority of studies in the EE group showed to be RCTs (97%), and the RWE group included mainly cohort studies (89%). There were more studies without a control group within RWE compared with the EE group (10% vs 1%). Our results showed that EE are more often assessed using Jadad, NICE or NOS scale by AOTMiT compared with RWE (93% vs 48%). When the best evidence within a given decision-making process is analysed, half of RWE and two-thirds of EE are considered high quality evidence. RWE plays an important role in the decision-making processes on public funding of drugs in Poland, contributing to nearly half (45%) of all the evidence considered. There exist such processes in which the proportion of RWE is dominant, with one process showing RWE as the only evidence presented. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  7. Experimental evidence of the decrease of kinetic energy of hadrons in passing through atomic nuclei

    NASA Technical Reports Server (NTRS)

    Strugalski, Z.

    1985-01-01

    Hadrons with kinetic energies higher than the pion production threshold lose their kinetic energies monotonically in traversing atomic nuclei, due to the strong interactions in nuclear matter. This phenomenon is a crude analogy to the energy loss of charged particles in their passage through materials. Experimental evidence is presented.

  8. Experimental evidence against the paradigm of mortality risk aversion.

    PubMed

    Rheinberger, Christoph M

    2010-04-01

    This article deals with the question of how societal impacts of fatal accidents can be integrated into the management of natural or man-made hazards. Today, many governmental agencies give additional weight to the number of potential fatalities in their risk assessments to reflect society's aversion to large accidents. Although mortality risk aversion has been proposed in numerous risk management guidelines, there has been no evidence that lay people want public decisionmakers to overweight infrequent accidents of large societal consequences against more frequent ones of smaller societal consequences. Furthermore, it is not known whether public decisionmakers actually do such overweighting when they decide upon the mitigation of natural or technical hazards. In this article, we report on two experimental tasks that required participants to evaluate negative prospects involving 1-100 potential fatalities. Our results show that neither lay people nor hazard experts exhibit risk-averse behavior in decisions on mortality risks.

  9. Speciation in caves: experimental evidence that permanent darkness promotes reproductive isolation

    PubMed Central

    Riesch, Rüdiger; Plath, Martin; Schlupp, Ingo

    2011-01-01

    Divergent selection through biotic factors like predation or parasitism can promote reproductive isolation even in the absence of geographical barriers. On the other hand, evidence for a role of adaptation to abiotic factors during ecological speciation in animals is scant. In particular, the role played by perpetual darkness in establishing reproductive isolation in cave animals (troglobites) remains elusive. We focused on two reproductively isolated ecotypes (surface- and cave-dwelling) of the widespread livebearer Poecilia mexicana, and raised offspring of wild-caught females to sexual maturity in a 12-month common-garden experiment. Fish were reared in light or darkness combined with high- or low-food conditions. Females, but not males, of the surface ecotype suffered from almost complete reproductive failure in darkness, especially in the low-food treatment. Furthermore, surface fish suffered from a significantly higher rate of spontaneous, stress-related infection with bacterial columnaris disease. This experimental evidence for strong selection by permanent darkness on non-adapted surface-dwelling animals adds depth to our understanding of the selective forces establishing and maintaining reproductive isolation in cave faunas. PMID:21561964

  10. Experimental evidence for action imitation in killer whales (Orcinus orca).

    PubMed

    Abramson, José Z; Hernández-Lloreda, Victoria; Call, Josep; Colmenares, Fernando

    2013-01-01

    Comparative experimental studies of imitative learning have focused mainly on primates and birds. However, cetaceans are promising candidates to display imitative learning as they have evolved in socioecological settings that have selected for large brains, complex sociality, and coordinated predatory tactics. Here we tested imitative learning in killer whales, Orcinus orca. We used a 'do-as-other-does' paradigm in which 3 subjects witnessed a conspecific demonstrator's performance that included 15 familiar and 4 novel behaviours. The three subjects (1) learned the copy command signal 'Do that' very quickly, that is, 20 trials on average; (2) copied 100 % of the demonstrator's familiar and novel actions; (3) achieved full matches in the first attempt for 8-13 familiar behaviours (out of 15) and for the 2 novel behaviours (out of 2) in one subject; and (4) took no longer than 8 trials to accurately copy any familiar behaviour, and no longer than 16 trials to copy any novel behaviour. This study provides experimental evidence for body imitation, including production imitation, in killer whales that is comparable to that observed in dolphins tested under similar conditions. These findings suggest that imitative learning may underpin some of the group-specific traditions reported in killer whales in the field.

  11. Experimental evidence of electromagnetic pollution of ionosphere

    NASA Astrophysics Data System (ADS)

    Pronenko, Vira; Korepanov, Valery; Dudkin, Denis

    multiple low orbiting satellites have confirmed a significant increase in their intensity over the populated areas of Europe and Asia. Recently, there are many experimental evidences of the existence of power line harmonic radiation (PLHR) in the ionosphere. Their spectra consist of succession of 50 (60) Hz harmonics which is accompanied by a set of lines separated by 50 (60) or 100 (120) Hz - the central frequency of which is shifted to high frequency. These lines cover rather wide band - according to the available experimental data, their central frequencies are observed from ~1.5 - 3 kHz up to 15 kHz, and recently the main mains frequencies are also observed. The examples of power line harmonic radiation, which were detected by “Sich-1M”, “Chibis-M” and “Demeter” satellites, have been presented and discussed. The available experimental data, as well as theoretical estimations, allow us with a high degree of certainty to say that the permanent satellite monitoring of the ionospheric and magnetospheric anthropogenic EM perturbations is necessary for: a) objective assessment and prediction of the space weather conditions; b) evaluation of the daily or seasonal changes in the level of energy consumption; c) construction of a map for estimation of near space EM pollution. This study is partially supported by SSAU contract N 4-03/13.

  12. Experimental evidence for superionic water ice using shock compression

    NASA Astrophysics Data System (ADS)

    Millot, Marius; Hamel, Sebastien; Rygg, J. Ryan; Celliers, Peter M.; Collins, Gilbert W.; Coppari, Federica; Fratanduono, Dayne E.; Jeanloz, Raymond; Swift, Damian C.; Eggert, Jon H.

    2018-03-01

    In stark contrast to common ice, Ih, water ice at planetary interior conditions has been predicted to become superionic with fast-diffusing (that is, liquid-like) hydrogen ions moving within a solid lattice of oxygen. Likely to constitute a large fraction of icy giant planets, this extraordinary phase has not been observed in the laboratory. Here, we report laser-driven shock-compression experiments on water ice VII. Using time-resolved optical pyrometry and laser velocimetry measurements as well as supporting density functional theory-molecular dynamics (DFT-MD) simulations, we document the shock equation of state of H2O to unprecedented extreme conditions and unravel thermodynamic signatures showing that ice melts near 5,000 K at 190 GPa. Optical reflectivity and absorption measurements also demonstrate the low electronic conductivity of ice, which, combined with previous measurements of the total electrical conductivity under reverberating shock compression, provides experimental evidence for superionic conduction in water ice at planetary interior conditions, verifying a 30-year-old prediction.

  13. Experimental and CFD evidence of multiple solutions in a naturally ventilated building.

    PubMed

    Heiselberg, P; Li, Y; Andersen, A; Bjerre, M; Chen, Z

    2004-02-01

    This paper considers the existence of multiple solutions to natural ventilation of a simple one-zone building, driven by combined thermal and opposing wind forces. The present analysis is an extension of an earlier analytical study of natural ventilation in a fully mixed building, and includes the effect of thermal stratification. Both computational and experimental investigations were carried out in parallel with an analytical investigation. When flow is dominated by thermal buoyancy, it was found experimentally that there is thermal stratification. When the flow is wind-dominated, the room is fully mixed. Results from all three methods have shown that the hysteresis phenomena exist. Under certain conditions, two different stable steady-state solutions are found to exist by all three methods for the same set of parameters. As shown by both the computational fluid dynamics (CFD) and experimental results, one of the solutions can shift to another when there is a sufficient perturbation. These results have probably provided the strongest evidence so far for the conclusion that multiple states exist in natural ventilation of simple buildings. Different initial conditions in the CFD simulations led to different solutions, suggesting that caution must be taken when adopting the commonly used 'zero initialization'.

  14. Experimental evidence of hepatitis A virus infection in pigs.

    PubMed

    Song, Young-Jo; Park, Woo-Jung; Park, Byung-Joo; Kwak, Sang-Woo; Kim, Yong-Hyeon; Lee, Joong-Bok; Park, Seung-Yong; Song, Chang-Seon; Lee, Sang-Won; Seo, Kun-Ho; Kang, Young-Sun; Park, Choi-Kyu; Song, Jae-Young; Choi, In-Soo

    2016-04-01

    Hepatitis A virus (HAV) is the leading cause of acute viral hepatitis worldwide, with HAV infection being restricted to humans and nonhuman primates. In this study, HAV infection status was serologically determined in domestic pigs and experimental infections of HAV were attempted to verify HAV infectivity in pigs. Antibodies specific to HAV or HAV-like agents were detected in 3.5% of serum samples collected from pigs in swine farms. When the pigs were infected intravenously with 2 × 10(5) 50% tissue culture infectious dose (TCID50 ) of HAV, shedding of the virus in feces, viremia, and seroconversion were detected. In pigs orally infected with the same quantity of HAV, viral shedding was detected only in feces. HAV genomic RNA was detected in the liver and bile of intravenously infected pigs, but only in the bile of orally infected pigs. In further experiments, pigs were intravenously infected with 6 × 10(5) TCID50 of HAV. Shedding of HAV in feces, along with viremia and seroconversion, were confirmed in infected pigs but not in sentinel pigs. HAV genomic RNA was detected in the liver, bile, spleen, lymph node, and kidney of the infected pigs. HAV antigenomic RNA was detected in the spleen of one HAV-infected pig, suggesting HAV replication in splenic cells. Infiltration of inflammatory cells was observed in the livers of infected pigs but not in controls. This is the first experimental evidence to demonstrate that human HAV strains can infect pigs. © 2015 Wiley Periodicals, Inc.

  15. The paradox of natural products as pharmaceuticals. Experimental evidences of a mango stem bark extract.

    PubMed

    Núñez-Sellés, Alberto J; Delgado-Hernández, René; Garrido-Garrido, Gabino; García-Rivera, Dagmar; Guevara-García, Mariela; Pardo-Andreu, Gilberto L

    2007-05-01

    Recent findings regarding basic, pre-clinical and clinical studies on a mango stem bark extract (MSBE) developed in Cuba (Vimang) on an industrial scale are summarized. Ethnomedical studies, extract reproducibility, biological effects and clinical evaluations in terms of patient quality of life are described as experimental evidences to support the statement that natural products, even being a mixture of compounds, could be as effective as "monoceuticals" for medical uses. Discussion about the use of "monoceuticals" versus "natureceuticals" in health care and medicine is based on effectiveness and availability, taking Vimang as an example of a natural product with supported scientific evidence to be used as antioxidant, analgesic, anti-inflammatory and immunomodulator.

  16. Delayed School Start Times and Adolescent Sleep: A Systematic Review of the Experimental Evidence

    PubMed Central

    Minges, Karl E.; Redeker, Nancy S.

    2016-01-01

    Summary Many schools have instituted later morning start times to improve sleep, academic, and other outcomes in response to the mismatch between youth circadian rhythms and early morning start times. However, there has been no systematic synthesis of the evidence on the effects of this practice. To examine the impact of delayed school start time on students’ sleep, health, and academic outcomes, electronic databases were systematically searched and data were extracted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Six studies satisfied selection criteria and used pre-post, no control (n=3), randomized controlled trial (n=2), and quasi-experimental (n=1) designs. School start times were delayed 25 to 60 minutes, and correspondingly, total sleep time increased from 25 to 77 minutes per weeknight. Some studies revealed reduced daytime sleepiness, depression, caffeine use, tardiness to class, and trouble staying awake. Overall, the evidence supports recent non-experimental study findings and calls for policy that advocates for delayed school start time to improve sleep. This presents a potential long-term solution to chronic sleep restriction during adolescence. However, there is a need for rigorous randomized study designs and reporting of consistent outcomes, including objective sleep measures and consistent measures of health and academic performance. PMID:26545246

  17. Experimental evidence for a new single-event upset (SEU) mode in a CMOS SRAM obtained from model verification

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Smith, L. S.; Soli, G. A.; Lo, R. Y.

    1987-01-01

    Modeling of SEU has been done in a CMOS static RAM containing 1-micron-channel-length transistors fabricated from a p-well epilayer process using both circuit-simulation and numerical-simulation techniques. The modeling results have been experimentally verified with the aid of heavy-ion beams obtained from a three-stage tandem van de Graaff accelerator. Experimental evidence for a novel SEU mode in an ON n-channel device is presented.

  18. Origin of Aphyric Phonolitic Magmas: Natural Evidences and Experimental Constraints

    NASA Astrophysics Data System (ADS)

    Masotta, M.; Freda, C.; Gaeta, M.

    2010-12-01

    Large explosive phonolitic eruptions are commonly characterised by aphyric juvenile eruptive products. Taking into account the low density contrast among phonolitic composition and settling phases (i.e., feldspar and leucite), the almost complete lack of crystals in these differentiated compositions rises the question of which process could produce such an efficient crystal-melt separation. Seeking for an answer, we have investigated crystallization in presence of a thermal gradient as a possible mechanism for crystal-melt separation, considering both chemical and physical effects acting on a variably crystallized system. Using a natural tephri-phonolitic composition as starting material (M.te Aguzzo scoria cone, Sabatini Volcanic District, Central Italy), we have reproduced thermal gradient-driven crystallization in order to simulate the crystallization process in a thermally zoned magma chamber. Crystallization degree (paragenesis made of clinopyroxene±feldspars±leucite) as well as melt composition varies along the thermal gradient. In particular, melt composition ranges from the tephri-phonolitic starting composition at the bottom of the charge (hottest and aphyric zone) to phonolitic at the top (cooler and heterogeneously-crystallised zone). Backscattered images of experimental products clearly evidence: i) the aphyric tephri-phonolitic melt region at the bottom of the charge; ii) a drop-shaped crystal clustering in the middle zone; and iii) large aphyric belt and pockets (up to 100 µm wide) of phonolitic melt, with large deformed-shaped sanidine occurring at their margin, at the charge top region. The latter two features, resulting from solid-melt displacements, suggest that the segregation of phonolitic melt can be related to crystal sinking and compaction. On the other hand, the compositional variability of the melt along the thermal gradient is directly related to the crystallization degree, indicating that chemical diffusion and thermal migration have

  19. Why Nudges Coerce: Experimental Evidence on the Architecture of Regulation.

    PubMed

    Hill, Adam

    2017-07-04

    Critics frequently argue that nudges are more covert, less transparent, and more difficult to monitor than traditional regulatory tools. Edward Glaeser, for example, argues that "[p]ublic monitoring of soft paternalism is much more difficult than public monitoring of hard paternalism". As one of the leading proponents of soft paternalism, Cass Sunstein, acknowledges, while "[m]andates and commands are highly visible", soft paternalism, "and some nudges in particular[,] may be invisible". In response to this challenge, proponents of nudging argue that invisibility for any given individual in a particular choice environment is compatible with "careful public scrutiny" of the nudge. This paper offers the first of its kind experimental evidence that tests whether nudges are, in fact, compatible with "careful public scrutiny". Using three sets of experiments, the paper argues that, even when entirely visible, nudges attract less scrutiny than their "hard law" counterparts.

  20. Experimental evidence of pollination in marine flowers by invertebrate fauna

    PubMed Central

    van Tussenbroek, Brigitta I.; Villamil, Nora; Márquez-Guzmán, Judith; Wong, Ricardo; Monroy-Velázquez, L. Verónica; Solis-Weiss, Vivianne

    2016-01-01

    Pollen transport by water-flow (hydrophily) is a typical, and almost exclusive, adaptation of plants to life in the marine environment. It is thought that, unlike terrestrial environments, animals are not involved in pollination in the sea. The male flowers of the tropical marine angiosperm Thalassia testudinum open-up and release pollen in mucilage at night when invertebrate fauna is active. Here we present experimental evidence that, in the absence of water-flow, these invertebrates visit the flowers, carry and transfer mucilage mass with embedded pollen from the male flowers to the stigmas of the female flowers. Pollen tubes are formed on the stigmas, indicating that pollination is successful. Thus, T. testudinum has mixed abiotic–biotic pollination. We propose a zoobenthophilous pollination syndrome (pollen transfer in the benthic zone by invertebrate animals) which shares many characteristics with hydrophily, but flowers are expected to open-up during the night. PMID:27680661

  1. Scientific reasoning in early and middle childhood: the development of domain-general evidence evaluation, experimentation, and hypothesis generation skills.

    PubMed

    Piekny, Jeanette; Maehler, Claudia

    2013-06-01

    According to Klahr's (2000, 2005; Klahr & Dunbar, 1988) Scientific Discovery as Dual Search model, inquiry processes require three cognitive components: hypothesis generation, experimentation, and evidence evaluation. The aim of the present study was to investigate (a) when the ability to evaluate perfect covariation, imperfect covariation, and non-covariation evidence emerges, (b) when experimentation emerges, (c) when hypothesis generation skills emerge, and (d), whether these abilities develop synchronously during childhood. We administered three scientific reasoning tasks referring to the three components to 223 children of five age groups (from age 4.0 to 13.5 years). Our results show that the three cognitive components of domain-general scientific reasoning emerge asynchronously. The development of domain-general scientific reasoning begins with the ability to handle unambiguous data, progresses to the interpretation of ambiguous data, and leads to a flexible adaptation of hypotheses according to the sufficiency of evidence. When children understand the relation between the level of ambiguity of evidence and the level of confidence in hypotheses, the ability to differentiate conclusive from inconclusive experiments accompanies this development. Implications of these results for designing science education concepts for young children are briefly discussed. © 2012 The British Psychological Society.

  2. Arsenic Exposure and Type 2 Diabetes: A Systematic Review of the Experimental and Epidemiologic Evidence

    PubMed Central

    Navas-Acien, Ana; Silbergeld, Ellen K.; Streeter, Robin A.; Clark, Jeanne M.; Burke, Thomas A.; Guallar, Eliseo

    2006-01-01

    Chronic arsenic exposure has been suggested to contribute to diabetes development. We performed a systematic review of the experimental and epidemiologic evidence on the association of arsenic and type 2 diabetes. We identified 19 in vitro studies of arsenic and glucose metabolism. Five studies reported that arsenic interfered with transcription factors involved in insulin-related gene expression: upstream factor 1 in pancreatic β-cells and peroxisome proliferative-activated receptor γ in preadipocytes. Other in vitro studies assessed the effect of arsenic on glucose uptake, typically using very high concentrations of arsenite or arsenate. These studies provide limited insight on potential mechanisms. We identified 10 in vivo studies in animals. These studies showed inconsistent effects of arsenic on glucose metabolism. Finally, we identified 19 epidemiologic studies (6 in high-arsenic areas in Taiwan and Bangladesh, 9 in occupational populations, and 4 in other populations). In studies from Taiwan and Bangladesh, the pooled relative risk estimate for diabetes comparing extreme arsenic exposure categories was 2.52 (95% confidence interval, 1.69–3.75), although methodologic problems limit the interpretation of the association. The evidence from occupational studies and from general populations other than Taiwan or Bangladesh was inconsistent. In summary, the current available evidence is inadequate to establish a causal role of arsenic in diabetes. Because arsenic exposure is widespread and diabetes prevalence is reaching epidemic proportions, experimental studies using arsenic concentrations relevant to human exposure and prospective epidemiologic studies measuring arsenic biomarkers and appropriately assessing diabetes should be a research priority. PMID:16675414

  3. Experimental evidence of thermal vibrational convection in a nonuniformly heated fluid in a reduced gravity environment.

    PubMed

    Mialdun, A; Ryzhkov, I I; Melnikov, D E; Shevtsova, V

    2008-08-22

    We report experimental evidence of convection caused by translational vibration of nonuniformly heated fluid in low gravity. The theory of vibrational convection in weightlessness is well developed but direct experimental proof has been missing. An innovative point of the experiment is the observation of a temperature field in the front and side views of the cubic cell. In addition, particle tracing is employed. The evolution of this field is studied systematically in a wide range of frequencies and amplitudes. The flow structures reported in previous numerical studies are confirmed. The transition from four-vortex flow to the pattern with three vortices is observed in the transient state.

  4. Experimental evidence of space charge driven resonances in high intensity linear accelerators

    DOE PAGES

    Jeon, Dong -O

    2016-01-12

    In the construction of high intensity accelerators, it is the utmost goal to minimize the beam loss by avoiding or minimizing contributions of various halo formation mechanisms. As a halo formation mechanism, space charge driven resonances are well known for circular accelerators. However, the recent finding showed that even in linear accelerators the space charge potential can excite the 4σ = 360° fourth order resonance [D. Jeon et al., Phys. Rev. ST Accel. Beams 12, 054204 (2009)]. This study increased the interests in space charge driven resonances of linear accelerators. Experimental studies of the space charge driven resonances of highmore » intensity linear accelerators are rare as opposed to the multitude of simulation studies. This paper presents an experimental evidence of the space charge driven 4σ ¼ 360° resonance and the 2σ x(y) – 2σ z = 0 resonance of a high intensity linear accelerator through beam profile measurements from multiple wire-scanners. Moreover, measured beam profiles agree well with the characteristics of the space charge driven 4σ = 360° resonance and the 2σ x(y) – 2σ z = 0 resonance that are predicted by the simulation.« less

  5. The impact of free trial acceptance on demand for alternative nicotine products: evidence from experimental auctions.

    PubMed

    Rousu, Matthew C; O'Connor, Richard J; Bansal-Travers, Maansi; Pitcavage, James M; Thrasher, James F

    2015-06-11

    This study explored the relationship between product trials and consumer demand for alternative nicotine products (ANP). An experimental auction was conducted with 258 adult smokers, wherein participants were randomly assigned to one of four experimental conditions. The participants received the opportunity to try, but did not have to accept, one of three relatively novel ST products (i.e., snus, dissolvable tobacco, or medicinal nicotine), or they were placed into a control group (i.e., no trial). All the participants then bid on all three of these products, as well as on cigarettes. We assessed interest in using ANP based on both trial of the product and bids placed for the products in the experimental auction. Fewer smokers were willing to try snus (44%) than dissolvable tobacco (64%) or medicine nicotine (68%). For snus, we find modest evidence suggesting that willingness to try is associated with greater demand for the product. For dissolvable tobacco or medicinal nicotine, we find no evidence that those who accept the product trial have higher demand for the product. Free trials of a novel ANP were not strongly associated with product demand, as assessed by willingness to pay. Given the debate over the potential for ANP to reduce the harm from smoking, these results are important in understanding the impact of free trial offers on adoption of ST product as a strategy to reduce harm from tobacco use.

  6. Biparental incubation-scheduling: no experimental evidence for major energetic constraints

    PubMed Central

    Cresswell, Will; Rutten, Anne L.; Valcu, Mihai; Kempenaers, Bart

    2015-01-01

    Incubation is energetically demanding, but it is debated whether these demands constrain incubation-scheduling (i.e., the length, constancy, and timing of incubation bouts) in cases where both parents incubate. Using 2 methods, we experimentally reduced the energetic demands of incubation in the semipalmated sandpiper, a biparental shorebird breeding in the harsh conditions of the high Arctic. First, we decreased the demands of incubation for 1 parent only by exchanging 1 of the 4 eggs for an artificial egg that heated up when the focal bird incubated. Second, we reanalyzed the data from the only published experimental study that has explicitly tested energetic constraints on incubation-scheduling in a biparentally incubating species (Cresswell et al. 2003). In this experiment, the energetic demands of incubation were decreased for both parents by insulating the nest cup. We expected that the treated birds, in both experiments, would change the length of their incubation bouts, if biparental incubation-scheduling is energetically constrained. However, we found no evidence that heating or insulation of the nest affected the length of incubation bouts: the combined effect of both experiments was an increase in bout length of 3.6min (95% CI: −33 to 40), which is equivalent to a 0.5% increase in the length of the average incubation bout. These results demonstrate that the observed biparental incubation-scheduling in semipalmated sandpipers is not primarily driven by energetic constraints and therefore by the state of the incubating bird, implying that we still do not understand the factors driving biparental incubation-scheduling. PMID:25713473

  7. Biparental incubation-scheduling: no experimental evidence for major energetic constraints.

    PubMed

    Bulla, Martin; Cresswell, Will; Rutten, Anne L; Valcu, Mihai; Kempenaers, Bart

    2015-01-01

    Incubation is energetically demanding, but it is debated whether these demands constrain incubation-scheduling (i.e., the length, constancy, and timing of incubation bouts) in cases where both parents incubate. Using 2 methods, we experimentally reduced the energetic demands of incubation in the semipalmated sandpiper, a biparental shorebird breeding in the harsh conditions of the high Arctic. First, we decreased the demands of incubation for 1 parent only by exchanging 1 of the 4 eggs for an artificial egg that heated up when the focal bird incubated. Second, we reanalyzed the data from the only published experimental study that has explicitly tested energetic constraints on incubation-scheduling in a biparentally incubating species (Cresswell et al. 2003). In this experiment, the energetic demands of incubation were decreased for both parents by insulating the nest cup. We expected that the treated birds, in both experiments, would change the length of their incubation bouts, if biparental incubation-scheduling is energetically constrained. However, we found no evidence that heating or insulation of the nest affected the length of incubation bouts: the combined effect of both experiments was an increase in bout length of 3.6min (95% CI: -33 to 40), which is equivalent to a 0.5% increase in the length of the average incubation bout. These results demonstrate that the observed biparental incubation-scheduling in semipalmated sandpipers is not primarily driven by energetic constraints and therefore by the state of the incubating bird, implying that we still do not understand the factors driving biparental incubation-scheduling.

  8. Behavioural evidence of magnetoreception in dolphins: detection of experimental magnetic fields

    NASA Astrophysics Data System (ADS)

    Kremers, Dorothee; López Marulanda, Juliana; Hausberger, Martine; Lemasson, Alban

    2014-11-01

    Magnetoreception, meaning the perception of magnetic fields, is supposed to play an important role for orientation/navigation in some terrestrial and aquatic species. Although some spatial observations of free-ranging cetaceans' migration routes and stranding sites led to the assumption that cetaceans may be sensitive to the geomagnetic field, experimental evidence is lacking. Here, we tested the spontaneous response of six captive bottlenose dolphins to the presentation of two magnetized and demagnetized controlled devices while they were swimming freely. Dolphins approached the device with shorter latency when it contained a strongly magnetized neodymium block compared to a control demagnetized block that was identical in form and density and therefore undistinguishable with echolocation. We conclude that dolphins are able to discriminate the two stimuli on the basis of their magnetic properties, a prerequisite for magnetoreception-based navigation.

  9. Behavioural evidence of magnetoreception in dolphins: detection of experimental magnetic fields.

    PubMed

    Kremers, Dorothee; López Marulanda, Juliana; Hausberger, Martine; Lemasson, Alban

    2014-11-01

    Magnetoreception, meaning the perception of magnetic fields, is supposed to play an important role for orientation/navigation in some terrestrial and aquatic species. Although some spatial observations of free-ranging cetaceans' migration routes and stranding sites led to the assumption that cetaceans may be sensitive to the geomagnetic field, experimental evidence is lacking. Here, we tested the spontaneous response of six captive bottlenose dolphins to the presentation of two magnetized and demagnetized controlled devices while they were swimming freely. Dolphins approached the device with shorter latency when it contained a strongly magnetized neodymium block compared to a control demagnetized block that was identical in form and density and therefore undistinguishable with echolocation. We conclude that dolphins are able to discriminate the two stimuli on the basis of their magnetic properties, a prerequisite for magnetoreception-based navigation.

  10. Evidence-based nursing: a stereotyped view of quantitative and experimental research could work against professional autonomy and authority.

    PubMed

    Bonell, C

    1999-07-01

    In recent years, there have been calls within the United Kingdom's National Health Service (NHS) for evidence-based health care. These resonate with long-standing calls for nursing to become a research-based profession. Evidence-based practice could enable nurses to demonstrate their unique contribution to health care outcomes, and support their seeking greater professionalization, in terms of enhanced authority and autonomy. Nursing's professionalization project, and, within this, various practices comprising the 'new nursing', whilst sometimes not delivering all that was hoped of them, have been important in developing certain conditions conducive to developing evidence-based practice, notably a critical perspective on practice and a reluctance merely to follow physicians' orders. However, nursing has often been hesitant in its adoption of quantitative and experimental research. This hesitancy, it is argued, has been influenced by the propounding by some authors within the new nursing of a stereotyped view of quantitative/experimental methods which equates them with a number of methodological and philosophical points which are deemed, by at least some of these authors, as inimical to, or problematic within, nursing research. It is argued that, not only is the logic on which the various stereotyped views are based flawed, but further, that the wider influence of these viewpoints on nurses could lead to a greater marginalization of nurses in research and evidence-based practice initiatives, thus perhaps leading to evidence-based nursing being led by other groups. In the longer term, this might result in a form of evidence-based nursing emphasizing routinization, thus--ironically--working against strategies of professional authority and autonomy embedded in the new nursing. Nursing research should instead follow the example of nurse researchers who already embrace multiple methods. While the paper describes United Kingdom experiences and debates, points raised about

  11. Self-Organization of Blood Pressure Regulation: Experimental Evidence

    PubMed Central

    Fortrat, Jacques-Olivier; Levrard, Thibaud; Courcinous, Sandrine; Victor, Jacques

    2016-01-01

    Blood pressure regulation is a prime example of homeostatic regulation. However, some characteristics of the cardiovascular system better match a non-linear self-organized system than a homeostatic one. To determine whether blood pressure regulation is self-organized, we repeated the seminal demonstration of self-organized control of movement, but applied it to the cardiovascular system. We looked for two distinctive features peculiar to self-organization: non-equilibrium phase transitions and hysteresis in their occurrence when the system is challenged. We challenged the cardiovascular system by means of slow, 20-min Tilt-Up and Tilt-Down tilt table tests in random order. We continuously determined the phase between oscillations at the breathing frequency of Total Peripheral Resistances and Heart Rate Variability by means of cross-spectral analysis. We looked for a significant phase drift during these procedures, which signed a non-equilibrium phase transition. We determined at which head-up tilt angle it occurred. We checked that this angle was significantly different between Tilt-Up and Tilt-Down to demonstrate hysteresis. We observed a significant non-equilibrium phase transition in nine healthy volunteers out of 11 with significant hysteresis (48.1 ± 7.5° and 21.8 ± 3.9° during Tilt-Up and Tilt-Down, respectively, p < 0.05). Our study shows experimental evidence of self-organized short-term blood pressure regulation. It provides new insights into blood pressure regulation and its related disorders. PMID:27065880

  12. Experimental evidence of locally resonant sonic band gap in two-dimensional phononic stubbed plates

    NASA Astrophysics Data System (ADS)

    Oudich, Mourad; Senesi, Matteo; Assouar, M. Badreddine; Ruzenne, Massimo; Sun, Jia-Hong; Vincent, Brice; Hou, Zhilin; Wu, Tsung-Tsong

    2011-10-01

    We provide experimental evidence of the existence of a locally resonant sonic band gap in a two-dimensional stubbed plate. Structures consisting of a periodic arrangement of silicone rubber stubs deposited on a thin aluminium plate were fabricated and characterized. Brillouin spectroscopy analysis is carried out to determine the elastic constants of the used rubber. The constants are then implemented in an efficient finite-element model that predicts the band structure and transmission to identify the theoretical band gap. We measure a complete sonic band gap for the out-of-plane Lamb wave modes propagating in various samples fabricated with different stub heights. Frequency domain measurements of full wave field and transmission are performed through a scanning laser Doppler vibrometer. A complete band gap from 1.9 to 2.6 kHz is showed using a sample with 6-mm stub diameter, 5-mm thickness, and 1-cm structure periodicity. Very good agreement between numerical and experimental results is obtained.

  13. Experimental evidence of a liquid-liquid transition in interfacial water

    NASA Astrophysics Data System (ADS)

    Zanotti, J.-M.; Bellissent-Funel, M.-C.; Chen, S.-H.

    2005-07-01

    At ambient pressure, bulk liquid water shows an anomalous increase of thermodynamic quantities and apparent divergences of dynamic properties on approaching a temperature Ts of 228 K. At normal pressure, supercooled water spontaneously freezes below the homogeneous nucleation temperature, TH = 235 K. Upon heating, the two forms of Amorphous Solid Water (ASW), LDA (Low Density Amorphous Ice) and HDA (High Density Amorphous Ice), crystallise above TX = 150 K. As a consequence, up to now no experiment has been able to explore the properties of liquid water in this very interesting temperature range between 150 and 235 K. We present nanosecond-time-scale measurements of local rotational and translational dynamics of interfacial, non-crystalline, water from 77 to 280 K. These experimental dynamic results are combined with calorimetric and diffraction data to show that after exhibiting a glass transition at 165 K, interfacial water experiences a first-order liquid-liquid transition at 240 K from a low-density to a high-density liquid. This is the first direct evidence of the existence of a liquid-liquid transition involving water.

  14. Gender-specific effects of early nutritional restriction on adult obesity risk: evidence from quasi-experimental studies.

    PubMed

    Robinson, Whitney R

    2012-12-01

    In countries undergoing nutrition transition and historically poor minority groups in wealthy countries, obesity tends to be more common in women than men. A potential contributor to this female excess of obesity is a mismatch between perinatal nutritional restriction and a later calorie-rich environment. Several epidemiologic and quasi-experimental studies support a gender-differential effect of early nutritional deprivation on adult obesity. The quasi-experimental studies are of particular interest because results of quasi-experimental studies are typically less vulnerable to confounding bias than observational studies. Four quasi-experimental studies-exploiting 20th century famines that occurred in Europe, Africa, and Asia-provide evidence that perinatal nutritional restriction followed by relative caloric abundance may increase adult obesity risk to a greater extent in women than men. If the findings are accurate and generalizable to contemporary food environments, they suggest that the female offspring of poor, or otherwise nutritionally restricted, women in rapidly developing and wealthy countries may be at particularly high risk of adult obesity. Research into gender-specific effects of early life nutritional deprivation and its interactions with later environmental exposures may provide insight into global gender differences in obesity prevalence.

  15. Market versus Residence Principle: Experimental Evidence on the Effects of a Financial Transaction Tax.

    PubMed

    Huber, Jürgen; Kirchler, Michael; Kleinlercher, Daniel; Sutter, Matthias

    2017-10-01

    The effects of a financial transaction tax (FTT) are scientifically disputed, as seemingly small details of its implementation may matter a lot. In this article, we provide experimental evidence on the different effects of an FTT, depending on whether it is implemented as a tax on markets, on residents, or a combination of both. We find that a tax on markets has negative effects on volatility and trading volume, whereas a tax on residents shows none of these undesired effects. Additionally, we observe that individual risk attitude is not related to traders' reaction to the different forms of an FTT.

  16. Experimental evidence of Ga-vacancy induced room temperature ferromagnetic behavior in GaN films

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Roul, Basanta; Kumar, Mahesh; Central Research Laboratory, Bharat Electronics, Bangalore 560013

    We have grown Ga deficient GaN epitaxial films on (0001) sapphire substrate by plasma-assisted molecular beam epitaxy and report the experimental evidence of room temperature ferromagnetic behavior. The observed yellow emission peak in room temperature photoluminescence spectra and the peak positioning at 300 cm{sup -1} in Raman spectra confirms the existence of Ga vacancies. The x-ray photoelectron spectroscopic measurements further confirmed the formation of Ga vacancies; since the N/Ga is found to be >1. The ferromagnetism is believed to originate from the polarization of the unpaired 2p electrons of N surrounding the Ga vacancy.

  17. Theoretical and experimental evidence for a nodal energy gap in MgB2

    NASA Astrophysics Data System (ADS)

    Agassi, Y. Dan; Oates, Daniel E.

    2017-11-01

    We present a phenomenological model that strongly suggests that the smaller of the two energy gaps in MgB2, the so-called π gap, contains nodal lines with a six-fold symmetry (i-wave). The model also indicates that the larger gap, the so-called σ gap, is conventional s-wave. The model is an extension of the BCS gap equation that accounts for the elastic anisotropy in MgB2 and the Coulomb repulsion. It is based on a phononic pairing mechanism and assumes no coupling between the two energy gaps in MgB2 at zero temperature. All of the parameters of the model, such as sound velocities and masses, are independently determined material constants. The results agree with a previous ad-hoc hypothesis that the π energy gap has six nodal lines. That hypothesis was motivated by low-temperature measurements of the surface impedance and intermodulation distortion in high-quality thin films. We briefly review experimental evidence in the literature that is relevant to the energy-gap symmetry. We find that the evidence from the literature for s-wave is inconclusive. Our finding is that the π gap has six nodal lines.

  18. Scientific Reasoning in Early and Middle Childhood: The Development of Domain-General Evidence Evaluation, Experimentation, and Hypothesis Generation Skills

    ERIC Educational Resources Information Center

    Piekny, Jeanette; Maehler, Claudia

    2013-01-01

    According to Klahr's (2000, 2005; Klahr & Dunbar, 1988) Scientific Discovery as Dual Search model, inquiry processes require three cognitive components: hypothesis generation, experimentation, and evidence evaluation. The aim of the present study was to investigate (a) when the ability to evaluate perfect covariation, imperfect covariation,…

  19. Genetics Home Reference: Pelizaeus-Merzbacher-like disease type 1

    MedlinePlus

    ... scale (dysmetria), tremors that occur mainly during movement (intention tremors), and head and neck tremors (titubation). People ... Available from http://www.ncbi.nlm.nih.gov/books/NBK470716/ Citation on PubMed Orthmann-Murphy JL, Freidin ...

  20. Role of Chronic Inflammation in Myopia Progression: Clinical Evidence and Experimental Validation.

    PubMed

    Lin, Hui-Ju; Wei, Chang-Ching; Chang, Ching-Yao; Chen, Ter-Hsin; Hsu, Yu-An; Hsieh, Yi-Ching; Chen, Hsuan-Ju; Wan, Lei

    2016-08-01

    Prevention and treatment of myopia is an important public problem worldwide. We found a higher incidence of myopia among patients with inflammatory diseases such as type 1 diabetes mellitus (7.9%), uveitis (3.7%), or systemic lupus erythematosus (3.5%) compared to those without inflammatory diseases (p<0.001) using data from children (<18years old) in the National Health Insurance Research database. We then examined the inhibition of myopia by atropine in Syrian hamsters with monocular form deprivation (MFD), an experimental myopia model. We found atropine downregulated inflammation in MFD eyes. The expression levels of c-Fos, nuclear factor κB (NFκB), interleukin (IL)-6, and tumor necrosis factor (TNF)-α were upregulated in myopic eyes and downregulated upon treatment with atropine. The relationship between the inflammatory response and myopia was investigated by treating MFD hamsters with the immunosuppressive agent cyclosporine A (CSA) or the inflammatory stimulators lipopolysaccharide (LPS) or peptidoglycan (PGN). Myopia progression was slowed by CSA application but was enhanced by LPS and PGN administration. The levels of c-Fos, NF-κB, IL-6, and TNF-α were upregulated in LPS- and PGN-treated eyes and downregulated by CSA treatment. These findings provide clinical and experimental evidence that inflammation plays a crucial role in the development of myopia. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Experimental evidence supports the abscess theory of development of radicular cysts.

    PubMed

    Nair, P N R; Sundqvist, Göran; Sjögren, Ulf

    2008-08-01

    The objective of this study was to experimentally induce inflammatory cysts in an animal model so as to test the hypothesis that radicular cysts develop via the "abscess pathway." Twenty-eight perforated custom-made Teflon cages were surgically implanted into defined locations in the back of 7 Sprague Dawley rats. A week after the implantation of the cages, a known quantity of freshly grown, close allogeneic oral keratinocytes in phosphate buffer solution (PBS) was injected into each cage. One cage per animal was treated as the control that received only epithelial cells. The remaining 3 cages of each animal were trials. Seven days post epithelial cell inoculation; a suspension of 0.2 mL of Fusobacterium nucleatum (10(8) bacteria per mL) was injected into each of the 3 trial cages. Two, 12, and 24 weeks after the inoculation of the bacteria, the cages were taken out, and the tissue contents were fixed and processed by correlative light and transmission electron microscopy. Sixteen of the 21 trial cages could be processed and yielded results. Inoculations of epithelial cells followed 1 week later by F. nucleatum into tissue cages resulted in the development inflammatory cysts in 2 of the 16 cages. The 2 cages contained a total of 4 cystic sites. None of the control cages showed the presence of any cyst-like pathology. Inflammatory cysts were induced by initiating acute inflammatory foci (abscess/necrotic area) by bacterial injection that got enclosed by a proliferating epithelium. This finding provides strong experimental evidence in support of the "abscess theory" of development of radicular cysts.

  2. Experimental evidence of massive-scale emotional contagion through social networks

    PubMed Central

    Kramer, Adam D. I.; Guillory, Jamie E.; Hancock, Jeffrey T.

    2014-01-01

    Emotional states can be transferred to others via emotional contagion, leading people to experience the same emotions without their awareness. Emotional contagion is well established in laboratory experiments, with people transferring positive and negative emotions to others. Data from a large real-world social network, collected over a 20-y period suggests that longer-lasting moods (e.g., depression, happiness) can be transferred through networks [Fowler JH, Christakis NA (2008) BMJ 337:a2338], although the results are controversial. In an experiment with people who use Facebook, we test whether emotional contagion occurs outside of in-person interaction between individuals by reducing the amount of emotional content in the News Feed. When positive expressions were reduced, people produced fewer positive posts and more negative posts; when negative expressions were reduced, the opposite pattern occurred. These results indicate that emotions expressed by others on Facebook influence our own emotions, constituting experimental evidence for massive-scale contagion via social networks. This work also suggests that, in contrast to prevailing assumptions, in-person interaction and nonverbal cues are not strictly necessary for emotional contagion, and that the observation of others’ positive experiences constitutes a positive experience for people. PMID:24889601

  3. Experimental evidences of the Gardner phase in a granular glass

    NASA Astrophysics Data System (ADS)

    Dauchot, Olivier; Seguin, Antoine

    The constituent particles of a glass are caged by their neighbors and thus cannot relax density fluctuations. This is also true for hard particles under compression. The associated slowing down of the dynamics is related to a complex free energy landscape. It was recently shown theoretically that the hard sphere glass in infinite dimension undergoes a Gardner transition, at which the glass basin breaks into a hierarchy of marginally stable sub-basins. This was very recently confirmed in simulations of 2d and 3d hard sphere (HS) glasses. We present the first direct experimental evidences of the Gardner phase, taking advantage of a well controlled granular experiment, which has already proven to successfully probe the vicinity of the jamming transition in a bi-dimensional granular glass former. More precisely, we perform independent compressions of a carefully prepared granular glass and show that for large enough compression, the final state differs from one compression to another. To do so we compare the average cage size within one state, and the average distance separating the cages of the same particles across successive compression cycles. The latter plateaus to a constant value, when entering the Gardner phase.

  4. Experimental evidence of massive-scale emotional contagion through social networks.

    PubMed

    Kramer, Adam D I; Guillory, Jamie E; Hancock, Jeffrey T

    2014-06-17

    Emotional states can be transferred to others via emotional contagion, leading people to experience the same emotions without their awareness. Emotional contagion is well established in laboratory experiments, with people transferring positive and negative emotions to others. Data from a large real-world social network, collected over a 20-y period suggests that longer-lasting moods (e.g., depression, happiness) can be transferred through networks [Fowler JH, Christakis NA (2008) BMJ 337:a2338], although the results are controversial. In an experiment with people who use Facebook, we test whether emotional contagion occurs outside of in-person interaction between individuals by reducing the amount of emotional content in the News Feed. When positive expressions were reduced, people produced fewer positive posts and more negative posts; when negative expressions were reduced, the opposite pattern occurred. These results indicate that emotions expressed by others on Facebook influence our own emotions, constituting experimental evidence for massive-scale contagion via social networks. This work also suggests that, in contrast to prevailing assumptions, in-person interaction and nonverbal cues are not strictly necessary for emotional contagion, and that the observation of others' positive experiences constitutes a positive experience for people.

  5. Experimental evidence for frequency dependent self-fertilization in the gynodioecious plant, Silene vulgaris.

    PubMed

    Miyake, Keiko; Olson, Matthew S

    2009-06-01

    After over a half century of empirical and theoretical research regarding the evolution and maintenance of gynodioecy in plants, unexplored factors influencing the relative fitnesses of females and hermaphrodites remain. Theoretical studies suggest that hermaphrodite self-fertilization (selfing) rate influences the maintenance of gynodioecy and we hypothesized that population sex ratio may influence hermaphrodite selfing rate. An experimental test for frequency-dependent self-fertilization was conducted using replicated populations constructed with different sex ratios of the gynodioecious plant Silene vulgaris. We found that hermaphrodite selfing increased with decreased hermaphrodite frequency, whereas evidence for increased inbreeding depression was equivocal. We argue that incorporation of context dependent inbreeding into future models of the evolution of gynodioecy is likely to yield novel insights into sex ratio evolution.

  6. Poverty, inequality, and increased consumption of high calorie food: Experimental evidence for a causal link.

    PubMed

    Bratanova, Boyka; Loughnan, Steve; Klein, Olivier; Claassen, Almudena; Wood, Robert

    2016-05-01

    Rising obesity represents a serious, global problem. It is now well established that obesity is associated with poverty and wealth inequality, suggesting that these factors may promote caloric intake. Whereas previous work has examined these links from an epidemiological perspective, the current paper examined them experimentally. In Study 1 we found that people experimentally induced to view themselves as poor (v. wealthy) exhibited increased calorie intake. In Study 2, participants who believed that they were poorer or wealthier than their interaction partners exhibited higher levels of anxiety compared to those in an equal partners condition; this anxiety in turn led to increased calorie consumption for people who had a strong need to belong. The findings provide causal evidence for the poverty-intake and inequality-intake links. Further, we identify social anxiety and a strong need to belong as important social psychological factors linking inequality to increased calorie intake. Copyright © 2016. Published by Elsevier Ltd.

  7. Direct, experimental evidence of the Fermi surface in YBa2Cu3O(7-x)

    NASA Astrophysics Data System (ADS)

    Haghighi, H.; Kaiser, J. H.; Rayner, S. L.; West, R. N.; Liu, J. Z.; Shelton, R.; Howell, R. H.; Sterne, P. A.; Solal, F. R.; Fluss, M. J.

    1991-04-01

    We report new measurements of the electron positron momentum spectra of YBa2Cu3O(7-x) performed with ultra-high statistical precision. These data differ from previous results in two significant respects: They show the D(sub 2) symmetry appropriate for untwinned crystals and, more importantly, they show unmistakable, statistically significant, discontinuities that are evidence of a major Fermi surface section. These results provide a partial answer to a question of special significance to the study of high temperature superconductors i.e., the distribution of the electrons in the material, the electronic structure. Special consideration has been given both experimentally and theoretically to the existence and shape of a Fermi surface in the materials and to the superconducting gap. There are only three experimental techniques that can provide details of the electronic structure at useful resolutions. They are angular correlation of positron annihilation radiation, ACAR, angle resolved photo emission, PE, and de Haas van Alphen measurements.

  8. Johari-Goldstein Relaxation Far Below Tg: Experimental Evidence for the Gardner Transition in Structural Glasses?

    NASA Astrophysics Data System (ADS)

    Geirhos, K.; Lunkenheimer, P.; Loidl, A.

    2018-02-01

    Experimental evidence for the Gardner transition, theoretically predicted to arise deep in the glassy state of matter, is scarce. At this transition, the energy landscape sensed by the particles forming the glass is expected to become more complex. In the present Letter, we report the dielectric response of two typical glass formers with well-pronounced Johari-Goldstein β relaxation, following this response down to unprecedented low temperatures, far below the glass transition. As the Johari-Goldstein process is believed to arise from the local structure of the energy landscape, its investigation seems an ideal tool to seek evidence for the Gardner transition. Indeed, we find an unusual broadening of the β relaxation below about 110 K for sorbitol and 100 K for xylitol, in excess of the expected broadening arising from a distribution of energy barriers. These results are well consistent with the presence of the Gardner transition in canonical structural glass formers.

  9. Experimental evidence of a φ Josephson junction.

    PubMed

    Sickinger, H; Lipman, A; Weides, M; Mints, R G; Kohlstedt, H; Koelle, D; Kleiner, R; Goldobin, E

    2012-09-07

    We demonstrate experimentally the existence of Josephson junctions having a doubly degenerate ground state with an average Josephson phase ψ=±φ. The value of φ can be chosen by design in the interval 0<φ<π. The junctions used in our experiments are fabricated as 0-π Josephson junctions of moderate normalized length with asymmetric 0 and π regions. We show that (a) these φ Josephson junctions have two critical currents, corresponding to the escape of the phase ψ from -φ and +φ states, (b) the phase ψ can be set to a particular state by tuning an external magnetic field, or (c) by using a proper bias current sweep sequence. The experimental observations are in agreement with previous theoretical predictions.

  10. Experimental evidence for real-time song frequency shift in response to urban noise in a passerine bird.

    PubMed

    Bermúdez-Cuamatzin, Eira; Ríos-Chelén, Alejandro A; Gil, Diego; Garcia, Constantino Macías

    2011-02-23

    Research has shown that bird songs are modified in different ways to deal with urban noise and promote signal transmission through noisy environments. Urban noise is composed of low frequencies, thus the observation that songs have a higher minimum frequency in noisy places suggests this is a way of avoiding noise masking. Most studies are correlative and there is as yet little experimental evidence that this is a short-term mechanism owing to individual plasticity. Here we experimentally test if house finches (Carpodacus mexicanus) can modulate the minimum frequency of their songs in response to different noise levels. We exposed singing males to three continuous treatments: low-high-low noise levels. We found a significant increase in minimum frequency from low to high and a decrement from high to low treatments. We also found that this was mostly achieved by modifying the frequency of the same low-frequency syllable types used in the different treatments. When different low-frequency syllables were used, those sung during the noisy condition were longer than the ones sang during the quiet condition. We conclude that house finches modify their songs in several ways in response to urban noise, thus providing evidence of a short-term acoustic adaptation.

  11. A review of experimental evidence for the carcinogenicity of man-made vitreous fibers.

    PubMed

    Davis, J M

    1986-01-01

    This paper reviews experimental studies on the carcinogenicity of man-made vitreous fibers. Long-term inhalation studies using several animal species and dust preparations of fibrous glass, rock wool or slag wool have produced little evidence of pulmonary fibrosis or pulmonary tumors. While some intratracheal injection studies found almost no pathological changes in lung tissue, some showed that pulmonary fibrosis can occur. Only one intratracheal injection study has reported that vitreous fibers can be carcinogenic; in contrast, many workers have reported that, following intrapleural or intraperitoneal injection, man-made vitreous fibers are highly carcinogenic, and tumor production appears to be closely related to fiber size. In vitro tests confirm that vitreous fibers can be toxic and can cause neoplastic transformation of cultured cells. The discrepancies between some experimental studies probably result from the relatively high solubility of most vitreous fibers. It seems likely that, while these fibers can survive in body cavities long enough to cause tumor production, they dissolve in lung tissue fast enough to have relatively little harmful effect. Rock-wool fibers appear more durable than glass- or slag-wool fibers, and, with similar fiber numbers and sizes in any dust cloud, this material is the most likely to have harmful potential.

  12. The scientific consensus on climate change as a gateway belief: experimental evidence.

    PubMed

    van der Linden, Sander L; Leiserowitz, Anthony A; Feinberg, Geoffrey D; Maibach, Edward W

    2015-01-01

    There is currently widespread public misunderstanding about the degree of scientific consensus on human-caused climate change, both in the US as well as internationally. Moreover, previous research has identified important associations between public perceptions of the scientific consensus, belief in climate change and support for climate policy. This paper extends this line of research by advancing and providing experimental evidence for a "gateway belief model" (GBM). Using national data (N = 1104) from a consensus-message experiment, we find that increasing public perceptions of the scientific consensus is significantly and causally associated with an increase in the belief that climate change is happening, human-caused and a worrisome threat. In turn, changes in these key beliefs are predictive of increased support for public action. In short, we find that perceived scientific agreement is an important gateway belief, ultimately influencing public responses to climate change.

  13. The Scientific Consensus on Climate Change as a Gateway Belief: Experimental Evidence

    PubMed Central

    van der Linden, Sander L.; Leiserowitz, Anthony A.; Feinberg, Geoffrey D.; Maibach, Edward W.

    2015-01-01

    There is currently widespread public misunderstanding about the degree of scientific consensus on human-caused climate change, both in the US as well as internationally. Moreover, previous research has identified important associations between public perceptions of the scientific consensus, belief in climate change and support for climate policy. This paper extends this line of research by advancing and providing experimental evidence for a “gateway belief model” (GBM). Using national data (N = 1104) from a consensus-message experiment, we find that increasing public perceptions of the scientific consensus is significantly and causally associated with an increase in the belief that climate change is happening, human-caused and a worrisome threat. In turn, changes in these key beliefs are predictive of increased support for public action. In short, we find that perceived scientific agreement is an important gateway belief, ultimately influencing public responses to climate change. PMID:25714347

  14. Isomer depletion as experimental evidence of nuclear excitation by electron capture

    NASA Astrophysics Data System (ADS)

    Chiara, C. J.; Carroll, J. J.; Carpenter, M. P.; Greene, J. P.; Hartley, D. J.; Janssens, R. V. F.; Lane, G. J.; Marsh, J. C.; Matters, D. A.; Polasik, M.; Rzadkiewicz, J.; Seweryniak, D.; Zhu, S.; Bottoni, S.; Hayes, A. B.; Karamian, S. A.

    2018-02-01

    The atomic nucleus and its electrons are often thought of as independent systems that are held together in the atom by their mutual attraction. Their interaction, however, leads to other important effects, such as providing an additional decay mode for excited nuclear states, whereby the nucleus releases energy by ejecting an atomic electron instead of by emitting a γ-ray. This ‘internal conversion’ has been known for about a hundred years and can be used to study nuclei and their interaction with their electrons. In the inverse process—nuclear excitation by electron capture (NEEC)—a free electron is captured into an atomic vacancy and can excite the nucleus to a higher-energy state, provided that the kinetic energy of the free electron plus the magnitude of its binding energy once captured matches the nuclear energy difference between the two states. NEEC was predicted in 1976 and has not hitherto been observed. Here we report evidence of NEEC in molybdenum-93 and determine the probability and cross-section for the process in a beam-based experimental scenario. Our results provide a standard for the assessment of theoretical models relevant to NEEC, which predict cross-sections that span many orders of magnitude. The greatest practical effect of the NEEC process may be on the survival of nuclei in stellar environments, in which it could excite isomers (that is, long-lived nuclear states) to shorter-lived states. Such excitations may reduce the abundance of the isotope after its production. This is an example of ‘isomer depletion’, which has been investigated previously through other reactions, but is used here to obtain evidence for NEEC.

  15. Live Fast, Die Young: Experimental Evidence of Population Extinction Risk due to Climate Change.

    PubMed

    Bestion, Elvire; Teyssier, Aimeric; Richard, Murielle; Clobert, Jean; Cote, Julien

    2015-10-01

    Evidence has accumulated in recent decades on the drastic impact of climate change on biodiversity. Warming temperatures have induced changes in species physiology, phenology, and have decreased body size. Such modifications can impact population dynamics and could lead to changes in life cycle and demography. More specifically, conceptual frameworks predict that global warming will severely threaten tropical ectotherms while temperate ectotherms should resist or even benefit from higher temperatures. However, experimental studies measuring the impacts of future warming trends on temperate ectotherms' life cycle and population persistence are lacking. Here we investigate the impacts of future climates on a model vertebrate ectotherm species using a large-scale warming experiment. We manipulated climatic conditions in 18 seminatural populations over two years to obtain a present climate treatment and a warm climate treatment matching IPCC predictions for future climate. Warmer temperatures caused a faster body growth, an earlier reproductive onset, and an increased voltinism, leading to a highly accelerated life cycle but also to a decrease in adult survival. A matrix population model predicts that warm climate populations in our experiment should go extinct in around 20 y. Comparing our experimental climatic conditions to conditions encountered by populations across Europe, we suggest that warming climates should threaten a significant number of populations at the southern range of the distribution. Our findings stress the importance of experimental approaches on the entire life cycle to more accurately predict population and species persistence in future climates.

  16. Live Fast, Die Young: Experimental Evidence of Population Extinction Risk due to Climate Change

    PubMed Central

    Bestion, Elvire; Teyssier, Aimeric; Richard, Murielle; Clobert, Jean; Cote, Julien

    2015-01-01

    Evidence has accumulated in recent decades on the drastic impact of climate change on biodiversity. Warming temperatures have induced changes in species physiology, phenology, and have decreased body size. Such modifications can impact population dynamics and could lead to changes in life cycle and demography. More specifically, conceptual frameworks predict that global warming will severely threaten tropical ectotherms while temperate ectotherms should resist or even benefit from higher temperatures. However, experimental studies measuring the impacts of future warming trends on temperate ectotherms' life cycle and population persistence are lacking. Here we investigate the impacts of future climates on a model vertebrate ectotherm species using a large-scale warming experiment. We manipulated climatic conditions in 18 seminatural populations over two years to obtain a present climate treatment and a warm climate treatment matching IPCC predictions for future climate. Warmer temperatures caused a faster body growth, an earlier reproductive onset, and an increased voltinism, leading to a highly accelerated life cycle but also to a decrease in adult survival. A matrix population model predicts that warm climate populations in our experiment should go extinct in around 20 y. Comparing our experimental climatic conditions to conditions encountered by populations across Europe, we suggest that warming climates should threaten a significant number of populations at the southern range of the distribution. Our findings stress the importance of experimental approaches on the entire life cycle to more accurately predict population and species persistence in future climates. PMID:26501958

  17. Experimental evidence of symmetry-breaking supercritical transition in pipe flow of shear-thinning fluids

    NASA Astrophysics Data System (ADS)

    Wen, Chaofan; Poole, Robert J.; Willis, Ashley P.; Dennis, David J. C.

    2017-03-01

    Experimental results reveal that the asymmetric flow of shear-thinning fluid through a cylindrical pipe, which was previously associated with the laminar-turbulent transition process, appears to have the characteristics of a nonhysteretic, supercritical instability of the laminar base state. Contrary to what was previously believed, classical transition is found to be responsible for returning symmetry to the flow. An absence of evidence of the instability in simulations (either linear or nonlinear) suggests that an element of physics is lacking in the commonly used rheological model for inelastic shear-thinning fluids. These unexpected discoveries raise new questions regarding the stability of these practically important fluids and how they can be successfully modeled.

  18. Self-deception as self-signalling: a model and experimental evidence

    PubMed Central

    Mijović-Prelec, Danica; Prelec, Draz̆en

    2010-01-01

    Self-deception has long been the subject of speculation and controversy in psychology, evolutionary biology and philosophy. According to an influential ‘deflationary’ view, the concept is an over-interpretation of what is in reality an instance of motivationally biased judgement. The opposite view takes the interpersonal deception analogy seriously, and holds that some part of the self actively manipulates information so as to mislead the other part. Building on an earlier self-signalling model of Bodner and Prelec, we present a game-theoretic model of self-deception. We propose that two distinct mechanisms collaborate to produce overt expressions of belief: a mechanism responsible for action selection (including verbal statements) and an interpretive mechanism that draws inferences from actions and generates emotional responses consistent with the inferences. The model distinguishes between two modes of self-deception, depending on whether the self-deceived individual regards his own statements as fully credible. The paper concludes with a new experimental study showing that self-deceptive judgements can be reliably and repeatedly elicited with financial incentives in a categorization task, and that the degree of self-deception varies with incentives. The study also finds evidence of the two forms of self-deception. The psychological benefits of self-deception, as measured by confidence, peak at moderate levels. PMID:20026461

  19. Experimental Evidence of Kinetic Effects in Indirect-Drive Inertial Confinement Fusion Hohlraums

    NASA Astrophysics Data System (ADS)

    Shan, L. Q.; Cai, H. B.; Zhang, W. S.; Tang, Q.; Zhang, F.; Song, Z. F.; Bi, B.; Ge, F. J.; Chen, J. B.; Liu, D. X.; Wang, W. W.; Yang, Z. H.; Qi, W.; Tian, C.; Yuan, Z. Q.; Zhang, B.; Yang, L.; Jiao, J. L.; Cui, B.; Zhou, W. M.; Cao, L. F.; Zhou, C. T.; Gu, Y. Q.; Zhang, B. H.; Zhu, S. P.; He, X. T.

    2018-05-01

    We present the first experimental evidence supported by simulations of kinetic effects launched in the interpenetration layer between the laser-driven hohlraum plasma bubbles and the corona plasma of the compressed pellet at the Shenguang-III prototype laser facility. Solid plastic capsules were coated with carbon-deuterium layers; as the implosion neutron yield is quenched, DD fusion yield from the corona plasma provides a direct measure of the kinetic effects inside the hohlraum. An anomalous large energy spread of the DD neutron signal (˜282 keV ) and anomalous scaling of the neutron yield with the thickness of the carbon-deuterium layers cannot be explained by the hydrodynamic mechanisms. Instead, these results can be attributed to kinetic shocks that arise in the hohlraum-wall-ablator interpenetration region, which result in efficient acceleration of the deuterons (˜28.8 J , 0.45% of the total input laser energy). These studies provide novel insight into the interactions and dynamics of a vacuum hohlraum and near-vacuum hohlraum.

  20. Evidence of low dimensional chaos in renal blood flow control in genetic and experimental hypertension

    NASA Astrophysics Data System (ADS)

    Yip, K.-P.; Marsh, D. J.; Holstein-Rathlou, N.-H.

    1995-01-01

    We applied a surrogate data technique to test for nonlinear structure in spontaneous fluctuations of hydrostatic pressure in renal tubules of hypertensive rats. Tubular pressure oscillates at 0.03-0.05 Hz in animals with normal blood pressure, but the fluctuations become irregular with chronic hypertension. Using time series from rats with hypertension we produced surrogate data sets to test whether they represent linearly correlated noise or ‘static’ nonlinear transforms of a linear stochastic process. The correlation dimension and the forecasting error were used as discriminating statistics to compare surrogate with experimental data. The results show that the original experimental time series can be distinguished from both linearly and static nonlinearly correlated noise, indicating that the nonlinear behavior is due to the intrinsic dynamics of the system. Together with other evidence this strongly suggests that a low dimensional chaotic attractor governs renal hemodynamics in hypertension. This appears to be the first demonstration of a transition to chaotic dynamics in an integrated physiological control system occurring in association with a pathological condition.

  1. Counter-intuitive experimental evidence on the initiation of radical crack in ceramic thin films at the atomic scale

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhuang, Chunqiang, E-mail: chunqiang.zhuang@bjut.edu.cn; Li, Zhipeng; Lin, Songsheng

    2015-10-15

    The basic issue related to radial crack in ceramic thin films has received considerable attention due to the fact that the radial crack plays an important role in evaluating the toughness properties of ceramic materials. In this work, an atomic-scale new experimental evidence is clearly presented to reveal the counter-intuitive initiation, the nucleation and the propagation mechanism of the radial crack in Al-Cr-N ceramic thin films.

  2. The experimental evidence for weight-loss treatment of essential hypertension: a critical review.

    PubMed Central

    Hovell, M F

    1982-01-01

    The empirical evidence concerning the therapeutic effects of weight loss for hypertension treatment was reviewed. Interventions were critically reviewed for strength of measures and experimental design. Six of 21 intervention studies proved to be methodologically strong. However, only one study was considered a randomized clinical trial, testing the combined effects of weight reduction and pharmacological treatment of hypertension. Average blood pressure decrease obtained from the methodologically strongest studies was -21 mmHg and -13 mmHg, for systolic and diastolic measures, respectively. This magnitude change suggests that weight loss may be a clinically and statistically significant treatment. Confounding and bias variables, such as adherence to diet, medication, salt consumption, etc., were discussed and future areas of research were outlined. It was concluded that weight loss appears to be an effective and safe treatment of hypertension. PMID:7039371

  3. Decompression to altitude: assumptions, experimental evidence, and future directions.

    PubMed

    Foster, Philip P; Butler, Bruce D

    2009-02-01

    Although differences exist, hypobaric and hyperbaric exposures share common physiological, biochemical, and clinical features, and their comparison may provide further insight into the mechanisms of decompression stress. Although altitude decompression illness (DCI) has been experienced by high-altitude Air Force pilots and is common in ground-based experiments simulating decompression profiles of extravehicular activities (EVAs) or astronauts' space walks, no case has been reported during actual EVAs in the non-weight-bearing microgravity environment of orbital space missions. We are uncertain whether gravity influences decompression outcomes via nitrogen tissue washout or via alterations related to skeletal muscle activity. However, robust experimental evidence demonstrated the role of skeletal muscle exercise, activities, and/or movement in bubble formation and DCI occurrence. Dualism of effects of exercise, positive or negative, on bubble formation and DCI is a striking feature in hypobaric exposure. Therefore, the discussion and the structure of this review are centered on those highlighted unresolved topics about the relationship between muscle activity, decompression, and microgravity. This article also provides, in the context of altitude decompression, an overview of the role of denitrogenation, metabolic gases, gas micronuclei, stabilization of bubbles, biochemical pathways activated by bubbles, nitric oxide, oxygen, anthropometric or physiological variables, Doppler-detectable bubbles, and potential arterialization of bubbles. These findings and uncertainties will produce further physiological challenges to solve in order to line up for the programmed human return to the Moon, the preparation for human exploration of Mars, and the EVAs implementation in a non-zero gravity environment.

  4. Experimental and clinical evidence for modification of hepatic ischaemia–reperfusion injury by N-acetylcysteine during major liver surgery

    PubMed Central

    Jegatheeswaran, Santhalingam; Siriwardena, Ajith K

    2011-01-01

    Background Hepatic ischaemia–reperfusion (I/R) injury occurs in both liver resectional surgery and in transplantation. The biochemistry of I/R injury involves short-lived oxygen free radicals. N-acetylcysteine (NAC) is a thiol-containing synthetic compound used in the treatment of acetaminophen toxicity. The present study is a detailed overview of the experimental and clinical evidence for the use of NAC as a pharmaco-protection agent in patients undergoing major liver surgery or transplantation. Methods A computerized search of the Medline, Embase and SCI databases for the period from 1st January 1988 to 31st December 2008 produced 40 reports. For clinical studies, the quality of reports was assessed according to the criteria reported by the Cochrane communication review group. Results Nineteen studies evaluated NAC in experimental liver I/R injury. NAC was administered before induction of ischaemia in 13. The most widely used concentration was 150 mg/kg by intravenous bolus. Fifteen studies report an improvement in outcome, predominantly a reduction in transaminase. Seven studies used an isolated perfused liver model with all showing improvement (predominantly an improvement in bile production after N-acetylcysteine). Two out of four transplantation models showed an improvement in hepatic function. Clinical studies in transplantation show a modest improvement in transaminase levels with no beneficial effect on either patient or graft survival. Conclusion N-acetylcysteine, given before induction of a liver I/R injury in an experimental model can ameliorate liver injury. Clinical outcome data are limited and there is currently little evidence to justify use either in liver transplantation or in liver resectional surgery. PMID:21241423

  5. Experimental and clinical evidence for loss of effect (tolerance) during prolonged treatment with antiepileptic drugs.

    PubMed

    Löscher, Wolfgang; Schmidt, Dieter

    2006-08-01

    Development of tolerance (i.e., the reduction in response to a drug after repeated administration) is an adaptive response of the body to prolonged exposure to the drug, and tolerance to antiepileptic drugs (AEDs) is no exception. Tolerance develops to some drug effects much more rapidly than to others. The extent of tolerance depends on the drug and individual (genetic?) factors. Tolerance may lead to attenuation of side effects but also to loss of efficacy of AEDs and is reversible after discontinuation of drug treatment. Different experimental approaches are used to study tolerance in laboratory animals. Development of tolerance depends on the experimental model, drug, drug dosage, and duration of treatment, so that a battery of experimental protocols is needed to evaluate fully whether tolerance to effect occurs. Two major types of tolerance are known. Pharmacokinetic (metabolic) tolerance, due to induction of AED-metabolizing enzymes has been shown for most first-generation AEDs, and is easy to overcome by increasing dosage. Pharmacodynamic (functional) tolerance is due to "adaptation" of AED targets (e.g., by loss of receptor sensitivity) and has been shown experimentally for all AEDs that lose activity during prolonged treatment. Functional tolerance may lead to complete loss of AED activity and cross-tolerance to other AEDs. Convincing experimental evidence indicates that almost all first-, second-, and third-generation AEDs lose their antiepileptic activity during prolonged treatment, although to a different extent. Because of diverse confounding factors, detecting tolerance in patients with epilepsy is more difficult but can be done with careful assessment of decline during long-term individual patient response. After excluding confounding factors, tolerance to antiepileptic effect for most modern and old AEDs can be shown in small subgroups of responders by assessing individual or group response. Development of tolerance to the antiepileptic activity of

  6. Xe incorporation in crust and upper mantle minerals: new experimental and theoretical evidences

    NASA Astrophysics Data System (ADS)

    Celine, C.; Sanloup, C.; Blanchard, M.; Lazzeri, M.; Balan, E.; Hudspeth, J.

    2017-12-01

    Storage of Xe in silicate minerals has been proposed to explain the `Missing Xenon' issue, i.e. the low Xe abundance in the Earth's and Mars' atmospheres compared to other noble gases [1]. However, data about Xe incorporation in minerals remain scarce due to high Xe volatility preventing studies at ambient conditions. Xe incorporations in olivine [2] and quartz [3] have been proposed based on experimental evidences at high pressures and temperatures. Nevertheless, Xe incorporation mechanisms remained so far only hypothetical. We present here new in situ X-ray diffraction data in diamond-anvil cell showing Xe incorporation in widespread silicate minerals of the continental crust (feldspars and quartz) and of the upper mantle (olivine) at relevant pressure and temperature conditions. Significant variations in cell parameters are retrieved in Xe-rich minerals as well as new peaks, implying change in the crystal structures linked to Xe incorporation. Theoretical calculations have been performed (using the density functional theory) to propose Xe incorporation sites able to reproduce experimental observations. In olivine, a Xe for Si substitutions is proposed, with up to 0.4 at% Xe potentially stored in olivine at depth. These new constraints on Xe incorporation at depths in silicate minerals, often neglected, could be crucial in the `Missing Xenon' issue. [1] Anders and Owen (1977) Science 198, 453-465, [2] Sanloup et al. (2011) Geochim. Cosmochim. Acta 75, 6271-6284, [3] Sanloup et al., (2005) Science, 310, 1174-1177

  7. Design and experimental evidence of a flat graded-index photonic crystal lens

    NASA Astrophysics Data System (ADS)

    Gaufillet, F.; Akmansoy, É.

    2013-08-01

    We report on the design and the experimental evidence of a flat graded index photonic crystal lens. The gradient has been designed so that the flat slab focuses a plane wave and so that it converts the wave issued from a point source into a plane wave. This graded-index photonic crystal lens operates as a convex lens. The gradient of index results from varying the filling factor of the photonic crystal in the direction perpendicular to that of the propagation of the electromagnetic field. The shape of the gradient of index has been designed by engineering the iso-frequency curves of the photonic crystal. As only a few layers were necessary and as graded photonic crystals may be fabricated by a variety of processes, this shows the ability of graded photonic crystals to efficiently apply for various photonic devices, from microwave range to the optical domain. 42.70.Qs Photonic bandgap materials, 78.67.Pt Optical properties of photonic structures, 41.20.Jb Electromagnetic wave propagation; radiowave propagation 84.40.Ba Antennas.

  8. Experimental Evidence for Quantum Tunneling Time

    NASA Astrophysics Data System (ADS)

    Camus, Nicolas; Yakaboylu, Enderalp; Fechner, Lutz; Klaiber, Michael; Laux, Martin; Mi, Yonghao; Hatsagortsyan, Karen Z.; Pfeifer, Thomas; Keitel, Christoph H.; Moshammer, Robert

    2017-07-01

    The first hundred attoseconds of the electron dynamics during strong field tunneling ionization are investigated. We quantify theoretically how the electron's classical trajectories in the continuum emerge from the tunneling process and test the results with those achieved in parallel from attoclock measurements. An especially high sensitivity on the tunneling barrier is accomplished here by comparing the momentum distributions of two atomic species of slightly deviating atomic potentials (argon and krypton) being ionized under absolutely identical conditions with near-infrared laser pulses (1300 nm). The agreement between experiment and theory provides clear evidence for a nonzero tunneling time delay and a nonvanishing longitudinal momentum of the electron at the "tunnel exit."

  9. Experimental evidence for non-Abelian gauge potentials in twisted graphene bilayers

    NASA Astrophysics Data System (ADS)

    Yin, Long-Jing; Qiao, Jia-Bin; Zuo, Wei-Jie; Li, Wen-Tian; He, Lin

    2015-08-01

    Non-Abelian gauge potentials are quite relevant in subatomic physics, but they are relatively rare in a condensed matter context. Here we report the experimental evidence for non-Abelian gauge potentials in twisted graphene bilayers by scanning tunneling microscopy and spectroscopy. At a magic twisted angle, θ ≈(1.11±0.05 ) ∘ , a pronounced sharp peak, which arises from the nondispersive flat bands at the charge neutrality point, is observed in the tunneling density of states due to the action of the non-Abelian gauge fields. Moreover, we observe confined electronic states in the twisted bilayer, as manifested by regularly spaced tunneling peaks with energy spacing δ E ≈vF/D ≈70 meV (here vF is the Fermi velocity of graphene and D is the period of the moiré patterns). This indicates that the non-Abelian gauge potentials in twisted graphene bilayers confine low-energy electrons into a triangular array of quantum dots following the modulation of the moiré patterns. Our results also directly demonstrate that the Fermi velocity in twisted bilayers can be tuned from about 106m /s to zero by simply reducing the twisted angle of about 2∘.

  10. Experimental evidence of chaotic mixing at pore scale in 3D porous media

    NASA Astrophysics Data System (ADS)

    Heyman, J.; Turuban, R.; Jimenez Martinez, J.; Lester, D. R.; Meheust, Y.; Le Borgne, T.

    2017-12-01

    Mixing of dissolved chemical species in porous media plays a central role in many natural and industrial processes, such as contaminant transport and degradation in soils, oxygen and nitrates delivery in river beds, clogging in geothermal systems, CO2 sequestration. In particular, incomplete mixing at the pore scale may strongly affect the spatio-temporal distribution of reaction rates in soils and rocks, questioning the validity of diffusion-reaction models at the Darcy scale. Recent theoretical [1] and numerical [2] studies of flow in idealized porous media have suggested that fluid mixing may be chaotic at pore scale, hence pointing to a whole new set of models for mixing and reaction in porous media. However, so far this remained to be confirmed experimentally. Here we present experimental evidence of the chaotic nature of transverse mixing at the pore scale in three-dimensional porous media. We designed a novel experimental setup allowing high resolution pore scale imaging of the structure of a tracer plume in porous media columns consisting of 7, 10 and 20 mm glass bead packings. We conjointly used refractive index matching techniques, laser induced fluorescence and a moving laser-sheet to reconstruct the shape of a steady tracer plume as it gets deformed by the porous media flow. In this talk, we focus on the transverse behavior of mixing, that is, on the plane orthogonal to the main flow direction, in the limit of high Péclet numbers (diffusion is negligible). Moving away from the injection point, the plume cross-section turns quickly into complex, interlaced, lamellar structures. These structures elongated at an exponential rate, characteristic of a chaotic system, that can be characterized by an average Lyapunov exponent. We finally discuss the origin of this chaotic behavior and its most significant consequences for upscaling mixing and reactive transport in porous media. Reference:[1] D. R. Lester, G. Metcafle, M. G. Trefry, Physical Review Letters

  11. Experimental Evidence for Quantum Tunneling Time.

    PubMed

    Camus, Nicolas; Yakaboylu, Enderalp; Fechner, Lutz; Klaiber, Michael; Laux, Martin; Mi, Yonghao; Hatsagortsyan, Karen Z; Pfeifer, Thomas; Keitel, Christoph H; Moshammer, Robert

    2017-07-14

    The first hundred attoseconds of the electron dynamics during strong field tunneling ionization are investigated. We quantify theoretically how the electron's classical trajectories in the continuum emerge from the tunneling process and test the results with those achieved in parallel from attoclock measurements. An especially high sensitivity on the tunneling barrier is accomplished here by comparing the momentum distributions of two atomic species of slightly deviating atomic potentials (argon and krypton) being ionized under absolutely identical conditions with near-infrared laser pulses (1300 nm). The agreement between experiment and theory provides clear evidence for a nonzero tunneling time delay and a nonvanishing longitudinal momentum of the electron at the "tunnel exit."

  12. Experimental evidence of turbulence regulation by time-varying E  ×  B flows

    NASA Astrophysics Data System (ADS)

    Silva, C.; Henriques, R.; Hidalgo, C.; Fernandes, H.

    2018-02-01

    The interaction between zonal flows and turbulence is a self-regulating mechanism. Understanding this interaction is crucial to control plasma confinement. Results presented in this paper aim at understanding the conditions under which geodesic acoustic modes (GAMs) influence turbulent transport. This is achieved by performing perturbative experiments where GAMs are stimulated and externally controlled. Experiments on ISTTOK revealed that increasing the GAM shear rate over its natural value leads to a reduction of the turbulent transport and to an enhancement in particle confinement. Taking advantage of our unique experimental tools, it is shown that GAMs play an important role in the regulation of the fluctuations, constituting further evidence that the GAM shear rate is enough to regulate the ambient fluctuations without totally suppressing the turbulence.

  13. Experimental evidence consistent with a magnon Nernst effect in the antiferromagnetic insulator MnPS3

    NASA Astrophysics Data System (ADS)

    Shiomi, Y.; Takashima, R.; Saitoh, E.

    2017-10-01

    A magnon Nernst effect, an antiferromagnetic analog of the magnon Hall effect in ferromagnetic insulators, has been studied experimentally for the layered antiferromagnetic insulator MnPS3 in contact with two Pt strips. Thermoelectric voltage in the Pt strips grown on MnPS3 single crystals exhibits nonmonotonic temperature dependence at low temperatures, which is unlikely to be explained by electronic origins in Pt but can be ascribed to the inverse spin Hall voltage induced by a magnon Nernst effect. Control of antiferromagnetic domains in the MnPS3 crystal by magnetoelectric cooling is found to modulate the low-temperature thermoelectric voltage in Pt, which is evidence consistent with the emergence of the magnon Nernst effect in Pt-MnPS3 hybrid structures.

  14. Towards the evidence of a purely spatial Einstein-Podolsky-Rosen paradox in images: measurement scheme and first experimental results

    NASA Astrophysics Data System (ADS)

    Devaux, F.; Mougin-Sisini, J.; Moreau, P. A.; Lantz, E.

    2012-07-01

    We propose a scheme to evidence the Einstein-Podolsky-Rosen (EPR) paradox for photons produced by spontaneous down conversion, from measurement of purely spatial correlations of photon positions both in the near- and in the far-field. Experimentally, quantum correlations have been measured in the far-field of parametric fluorescence created in a type II BBO crystal. Imaging is performed in the photon counting regime with an electron-multiplying CCD (EMCCD) camera.

  15. Evidence-Based Special Education in the Context of Scarce Evidence-Based Practices

    ERIC Educational Resources Information Center

    TEACHING Exceptional Children, 2014

    2014-01-01

    Evidence-based practices (EBPs) are supported as generally effective for populations of learners by bodies of high-quality and experimental research and, when aligned with stakeholder values and practical needs, should be prioritized for implementation. However, evidence-based practices are not currently available for all learner types in all…

  16. Evidence for side-chain π-delocalization in a planar substituted benzene: an experimental and theoretical charge density study on 2,5-dimethoxybenzaldehyde thiosemicarbazone.

    PubMed

    Farrugia, Louis J; Khalaji, Aliakbar Dehno

    2011-11-17

    The charge density in 2,5-dimethoxybenzaldehyde thiosemicarbazone (1) has been studied experimentally using Mo-K(α) X-ray diffraction at 100 K, and by theory using DFT calculations at the B3LYP/6-311++G(2d,2p) level. The quantum theory of atoms in molecules (QTAIM) was used to investigate the extent of π-delocalization in the thioamide side-chain, which is virtually coplanar with the benzene ring. The experimental and theoretical ellipticity profiles along the bond paths were in excellent agreement, and showed that some of the formal single bonds in the side-chain have significant π-bond character. This view was supported by the magnitudes of the topological bond orders and by the delocalization indices δ(Ω(A), Ω(B)). An orbital decomposition of δ(Ω(A), Ω(B)) demonstrated that there was significant π-character in all the interchain non-H chemical bonds. On the other hand, the source function referenced at the interchain bond critical points could not provide any evidence for π-delocalization, showing instead only limited σ-delocalization between nearest neighbors. Overall, the topological evidence and the atomic graphs of the oxygen atoms did not provide convincing evidence for π-delocalization involving the methoxy substituents.

  17. Bilateral oligopoly in pollution permit markets: experimental evidence

    USDA-ARS?s Scientific Manuscript database

    We experimentally investigate behavior in a bilateral oligopoly using a supply function equilibria model (Klemper and Meyer 1989; Hendricks and McAfee 2010; Malueg and Yates 2009). We focus on the role that market size and the degree of firm heterogeneity have on the market equilibrium. Our results ...

  18. The impact of product information and trials on demand for smokeless tobacco and cigarettes: Evidence from experimental auctions

    PubMed Central

    Rousu, Matthew C.; O'Connor, Richard; Thrasher, James F; June, Kristie; Bansal-Travers, Maansi; Pitcavage, James

    2014-01-01

    Introduction Epidemiological and toxicological evidence suggests lower risk of smokeless tobacco (ST) products compared to cigarettes. Less is known, however, about consumer perceptions and use of novel forms of ST, including snus and dissolvable tobacco. Methods In this study, we conducted in-person experimental auctions in Buffalo, NY, Columbia, SC, and Selinsgrove, PA with 571 smokers to test the impact of information and product trials on smokers’ preferences. Auctions were conducted between November 2010-November 2011. Results We found no evidence of an impact of product trials on demand in our auctions. Anti-ST information increased demand for cigarettes when presented alone, but when presented with Pro-ST information it decreased demand for cigarettes. It did not decrease demand for ST products. Anti-smoking information increased demand for ST products, but did not affect cigarette demand. Conclusions These findings suggest that credible and effective communications about tobacco harm reduction should reinforce the negative effects of smoking. PMID:24321456

  19. The impact of product information and trials on demand for smokeless tobacco and cigarettes: evidence from experimental auctions.

    PubMed

    Rousu, Matthew C; O'Connor, Richard J; Thrasher, James F; June, Kristie M; Bansal-Travers, Maansi; Pitcavage, James

    2014-03-01

    Epidemiological and toxicological evidence suggests lower risk of smokeless tobacco (ST) products compared to cigarettes. Less is known, however, about consumer perceptions and use of novel forms of ST, including snus and dissolvable tobacco. In this study, we conducted in-person experimental auctions in Buffalo, NY, Columbia, SC, and Selinsgrove, PA with 571 smokers to test the impact of information and product trials on smokers' preferences. Auctions were conducted between November 2010-November 2011. We found no evidence of an impact of product trials on demand in our auctions. Anti-ST information increased demand for cigarettes when presented alone, but when presented with pro-ST information it decreased demand for cigarettes. It did not decrease demand for ST products. Anti-smoking information increased demand for ST products, but did not affect cigarette demand. These findings suggest that credible and effective communications about tobacco harm reduction should reinforce the negative effects of smoking. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Experimental Evidence for a Structural-Dynamical Transition in Trajectory Space.

    PubMed

    Pinchaipat, Rattachai; Campo, Matteo; Turci, Francesco; Hallett, James E; Speck, Thomas; Royall, C Patrick

    2017-07-14

    Among the key insights into the glass transition has been the identification of a nonequilibrium phase transition in trajectory space which reveals phase coexistence between the normal supercooled liquid (active phase) and a glassy state (inactive phase). Here, we present evidence that such a transition occurs in experiments. In colloidal hard spheres, we find a non-Gaussian distribution of trajectories leaning towards those rich in locally favored structures (LFSs), associated with the emergence of slow dynamics. This we interpret as evidence for a nonequilibrium transition to an inactive LFS-rich phase. Reweighting trajectories reveals a first-order phase transition in trajectory space between a normal liquid and a LFS-rich phase. We also find evidence for a purely dynamical transition in trajectory space.

  1. Experimenter bias and subliminal perception

    ERIC Educational Resources Information Center

    Barber, Paul J.; Rushton, J. Philippe

    1975-01-01

    It has been suggested that subliminal perception phenomena may be in part due to experimenter bias effects. Two studies that obtained positive evidence of subliminal perception were therefore replicated with experimenters tested under blind and not blind conditions. (Editor)

  2. The Hissar–Alay and the Pamirs: Deep-Seated Structure, Geodynamic Model, and Experimental Evidence

    NASA Astrophysics Data System (ADS)

    Leonov, M. G.; Rybin, A. K.; Batalev, V. Yu.; Matyukov, V. E.; Shchelochkov, G. G.

    2018-03-01

    The structural and geodynamic features of the Pamirs and the Hissar-Alay have been revealed based on geological and geophysical evidence supplemented by experimental data. It has been shown that both the Pamirs and the Hissar-Alay are geodynamic systems, the formation of which is related to interference of two geodynamic regimes: (i) global orogeny covering extensive territories of Eurasia and determining their similarity and (ii) regional regimes differing for the Pamirs and the Alay, which act independently within Central Asian and Apline-Himalayan mobile belts, respectively. The Pamirs do not act as an indentor during the formation of structure of the Hissar-Alay and areas to the north. It is stated that the Pamir-Alay segment of Asia is a reflection of the geodynamic countermotion setting (3D flow of mountain masses) of several distinct segments of the continental lithosphere, while the Pamirs are an intracontinental subduction domain at the surface, which represents a special tectonic-geodynamic type of structures.

  3. Enjoyment: A Conceptual Exploration and Overview of Experimental Evidence in the Context of Games for Health.

    PubMed

    Crutzen, Rik; van 't Riet, Jonathan; Short, Camille E

    2016-02-01

    Enjoyment is consistently noted as important for engaging audiences in games for health. However, as a term, enjoyment is often used interchangeably with a host of other terms, some of which overlap conceptually. This obscures what does and what does not constitute enjoyment, and in turn slows scientific progress by making the study of enjoyment and the synthesis of enjoyment-related research difficult. This article is aimed at improving our understanding of enjoyment by distinguishing enjoyment from other important constructs, such as fun and engagement, and by providing an overview of the experimental evidence on the determinants of enjoyment in videogames. Competence, narrative transportation, and relevance are identified as key factors related to enjoyment, and future studies examining these factors using games for health are recommended.

  4. Experimental evidence of the spatial coherence moiré and the filtering of classes of radiator pairs.

    PubMed

    Castaneda, Roman; Usuga-Castaneda, Mario; Herrera-Ramírez, Jorge

    2007-08-01

    Evidence of the physical existence of the spatial coherence moiré is obtained by confronting numerical results with experimental results of spatially partial interference. Although it was performed for two particular cases, the results reveal a general behavior of the optical fields in any state of spatial coherence. Moreover, the study of the spatial coherence moiré deals with a new type of filtering, named filtering of classes of radiator pairs, which allows changing the power spectrum at the observation plane by modulating the complex degree of spatial coherence, without altering the power distribution at the aperture plane or introducing conventional spatial filters. This new procedure can optimize some technological applications of actual interest, as the beam shaping for instance.

  5. Bisphenol A and Reproductive Health: Update of Experimental and Human Evidence, 2007–2013

    PubMed Central

    Peretz, Jackye; Vrooman, Lisa; Ricke, William A.; Hunt, Patricia A.; Ehrlich, Shelley; Hauser, Russ; Padmanabhan, Vasantha; Taylor, Hugh S.; Swan, Shanna H.; VandeVoort, Catherine A.

    2014-01-01

    health: update of experimental and human evidence, 2007–2013. Environ Health Perspect 122:775–786; http://dx.doi.org/10.1289/ehp.1307728 PMID:24896072

  6. Constructing a new theory from old ideas and new evidence

    PubMed Central

    Rhodes, Marjorie; Wellman, Henry

    2014-01-01

    A central tenet of constructivist models of conceptual development is that children’s initial conceptual level constrains how they make sense of new evidence and thus whether exposure to evidence will prompt conceptual change. Yet, little experimental evidence directly examines this claim for the case of sustained, fundamental conceptual achievements. The present study combined scaling and experimental microgenetic methods to examine the processes underlying conceptual change in the context of an important conceptual achievement of early childhood—the development of a representational theory of mind. Results from 47 children (M age = 3.7 years) indicate that only children who were conceptually close to understanding false belief at the beginning of the study, and who were experimentally exposed to evidence of people acting on false beliefs, reliably developed representational theories of minds. Combined scaling and microgenetic data revealed how prior conceptual level interacts with experience, thereby providing critical experimental evidence for how conceptual change results from the interplay between conceptions and evidence. PMID:23489194

  7. Transanal total mesorectal excision: a systematic review of the experimental and clinical evidence.

    PubMed

    Araujo, S E; Crawshaw, B; Mendes, C R; Delaney, C P

    2015-02-01

    Achieving a clear distal or circumferential resection margins with laparoscopic total mesorectal excision (TME) may be laborious, especially in obese males and when operating on advanced distal rectal tumors with a poor response to neoadjuvant treatment. Transanal (TaTME) is a new natural orifice translumenal endoscopic surgery modality in which the rectum is mobilized transanally using endoscopic techniques with or without laparoscopic assistance. We conducted a comprehensive systematic review of publications on this new technique in PubMed and Embase databases from January, 2008, to July, 2014. Experimental and clinical studies written in English were included. Experimental research with TaTME was done on pigs with and without survival models and on human cadavers. In these studies, laparoscopic or transgastric assistance was frequently used resulting in an easier upper rectal dissection and in a longer rectal specimen. To date, 150 patients in 16 clinical studies have undergone TaTME. In all but 15 cases, transabdominal assistance was used. A rigid transanal endoscopic operations/transanal endoscopic microsurgery (TEO/TEM) platform was used in 37 patients. Rectal adenocarcinoma was the indication in all except for nine cases of benign diseases. Operative times ranged from 90 to 460 min. TME quality was deemed intact, satisfactory, or complete. Involvement in circumferential resection margins was detected in 16 (11.8 %) patients. The mean lymph node harvest was equal or greater than 12 in all studies. Regarding morbidity, pneumoretroperitoneum, damage to the urethra, and air embolism were reported intraoperatively. Mean hospital stay varied from 4 to 14 days. Postoperative complications occurred in 34 (22.7 %) patients. TaTME with TEM is feasible in selected cases. Oncologic safety parameters seem to be adequate although the evidence relies on small retrospective series conducted by highly trained surgeons. Further studies are expected.

  8. Flutter and divergence instability in the Pflüger column: Experimental evidence of the Ziegler destabilization paradox

    NASA Astrophysics Data System (ADS)

    Bigoni, Davide; Kirillov, Oleg N.; Misseroni, Diego; Noselli, Giovanni; Tommasini, Mirko

    2018-07-01

    Flutter instability in elastic structures subject to follower load, the most important cases being the famous Beck's and Pflüger's columns (two elastic rods in a cantilever configuration, with an additional concentrated mass at the end of the rod in the latter case), have attracted, and still attract, a thorough research interest. In this field, the most important issue is the validation of the model itself of follower force, a nonconservative action which was harshly criticized and never realized in practice for structures with diffused elasticity. An experimental setup to introduce follower tangential forces at the end of an elastic rod was designed, realized, validated, and tested, in which the follower action is produced by exploiting Coulomb friction on an element (a freely-rotating wheel) in sliding contact against a flat surface (realized by a conveyor belt). It is therefore shown that follower forces can be realized in practice and the first experimental evidence is given for both the flutter and divergence instabilities occurring in the Pflüger's column. In particular, load thresholds for the two instabilities are measured and the detrimental effect of dissipation on the critical load for flutter is experimentally demonstrated, while a slight increase in load is found for the divergence instability. The presented approach to follower forces discloses new horizons for testing self-oscillating structures and for exploring and documenting dynamic instabilities possible when nonconservative loads are applied.

  9. Cash transfers, maternal depression and emotional well-being: Quasi-experimental evidence from India's Janani Suraksha Yojana programme.

    PubMed

    Powell-Jackson, Timothy; Pereira, Shreya K; Dutt, Varun; Tougher, Sarah; Haldar, Kaveri; Kumar, Paresh

    2016-08-01

    Maternal depression is an important public health concern. We investigated whether a national-scale initiative that provides cash transfers to women giving birth in government health facilities, the Janani Suraksha Yojana (JSY), reduced maternal depression in India's largest state, Uttar Pradesh. Using primary data on 1695 women collected in early 2015, our quasi-experimental design exploited the fact that some women did not receive the JSY cash due to administrative problems in its disbursement - reasons that are unlikely to be correlated with determinants of maternal depression. We found that receipt of the cash was associated with an 8.5% reduction in the continuous measure of maternal depression and a 36% reduction in moderate depression. There was no evidence of an association with measures of emotional well-being, namely happiness and worry. The results suggest that the JSY had a clinically meaningful effect in reducing the burden of maternal depression, possibly by lessening the financial strain of delivery care. They contribute to the evidence that financial incentive schemes may have public health benefits beyond improving uptake of targeted health services. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Experimental evidence that wildflower strips increase pollinator visits to crops.

    PubMed

    Feltham, Hannah; Park, Kirsty; Minderman, Jeroen; Goulson, Dave

    2015-08-01

    Wild bees provide a free and potentially diverse ecosystem service to farmers growing pollination-dependent crops. While many crops benefit from insect pollination, soft fruit crops, including strawberries are highly dependent on this ecosystem service to produce viable fruit. However, as a result of intensive farming practices and declining pollinator populations, farmers are increasingly turning to commercially reared bees to ensure that crops are adequately pollinated throughout the season. Wildflower strips are a commonly used measure aimed at the conservation of wild pollinators. It has been suggested that commercial crops may also benefit from the presence of noncrop flowers; however, the efficacy and economic benefits of sowing flower strips for crops remain relatively unstudied. In a study system that utilizes both wild and commercial pollinators, we test whether wildflower strips increase the number of visits to adjacent commercial strawberry crops by pollinating insects. We quantified this by experimentally sowing wildflower strips approximately 20 meters away from the crop and recording the number of pollinator visits to crops with, and without, flower strips. Between June and August 2013, we walked 292 crop transects at six farms in Scotland, recording a total of 2826 pollinators. On average, the frequency of pollinator visits was 25% higher for crops with adjacent flower strips compared to those without, with a combination of wild and commercial bumblebees (Bombus spp.) accounting for 67% of all pollinators observed. This effect was independent of other confounding effects, such as the number of flowers on the crop, date, and temperature. Synthesis and applications. This study provides evidence that soft fruit farmers can increase the number of pollinators that visit their crops by sowing inexpensive flower seed mixes nearby. By investing in this management option, farmers have the potential to increase and sustain pollinator populations over time.

  11. Experimental evidence that wildflower strips increase pollinator visits to crops

    PubMed Central

    Feltham, Hannah; Park, Kirsty; Minderman, Jeroen; Goulson, Dave

    2015-01-01

    Wild bees provide a free and potentially diverse ecosystem service to farmers growing pollination-dependent crops. While many crops benefit from insect pollination, soft fruit crops, including strawberries are highly dependent on this ecosystem service to produce viable fruit. However, as a result of intensive farming practices and declining pollinator populations, farmers are increasingly turning to commercially reared bees to ensure that crops are adequately pollinated throughout the season. Wildflower strips are a commonly used measure aimed at the conservation of wild pollinators. It has been suggested that commercial crops may also benefit from the presence of noncrop flowers; however, the efficacy and economic benefits of sowing flower strips for crops remain relatively unstudied. In a study system that utilizes both wild and commercial pollinators, we test whether wildflower strips increase the number of visits to adjacent commercial strawberry crops by pollinating insects. We quantified this by experimentally sowing wildflower strips approximately 20 meters away from the crop and recording the number of pollinator visits to crops with, and without, flower strips. Between June and August 2013, we walked 292 crop transects at six farms in Scotland, recording a total of 2826 pollinators. On average, the frequency of pollinator visits was 25% higher for crops with adjacent flower strips compared to those without, with a combination of wild and commercial bumblebees (Bombus spp.) accounting for 67% of all pollinators observed. This effect was independent of other confounding effects, such as the number of flowers on the crop, date, and temperature. Synthesis and applications. This study provides evidence that soft fruit farmers can increase the number of pollinators that visit their crops by sowing inexpensive flower seed mixes nearby. By investing in this management option, farmers have the potential to increase and sustain pollinator populations over time

  12. Nanostructured diamine-fullerene derivatives: computational density functional theory study and experimental evidence for their formation via gas-phase functionalization.

    PubMed

    Contreras-Torres, Flavio F; Basiuk, Elena V; Basiuk, Vladimir A; Meza-Laguna, Víctor; Gromovoy, Taras Yu

    2012-02-16

    Nanostructure derivatives of fullerene C(60) are used in emerging applications of composite matrices, including protective and decorative coating, superadsorbent material, thin films, and lightweight high-strength fiber-reinforced materials, etc. In this study, quantum chemical calculations and experimental studies were performed to analyze the derivatives of diamine-fullerene prepared by the gas-phase solvent-free functionalization technique. In particular, the aliphatic 1,8-diamino-octane and the aromatic 1,5-diaminonaphthalene, which are diamines volatile in vacuum, were studied. We addressed two alternative mechanisms of the amination reaction via polyaddition and cross-linking of C(60) with diamines, using the pure GGA BLYP, PW91, and PBE functionals; further validation calculations were performed using the semiempirical dispersion GGA B97-D functional which contains parameters that have been specially adjusted by a more realistic view on dispersion contributions. In addition, we looked for experimental evidence for the covalent functionalization by using laser desorption/ionization time-of-flight mass spectrometry, thermogravimetric analysis, and atomic force microscopy.

  13. Enhancing the gene-environment interaction framework through a quasi-experimental research design: evidence from differential responses to September 11.

    PubMed

    Fletcher, Jason M

    2014-01-01

    This article uses a gene-environment interaction framework to examine the differential responses to an objective external stressor based on genetic variation in the production of depressive symptoms. This article advances the literature by utilizing a quasi-experimental environmental exposure design, as well as a regression discontinuity design, to control for seasonal trends, which limit the potential for gene-environment correlation and allow stronger causal claims. Replications are attempted for two prominent genes (5-HTT and MAOA), and three additional genes are explored (DRD2, DRD4, and DAT1). This article provides evidence of a main effect of 9/11 on reports of feelings of sadness and fails to replicate a common finding of interaction using 5-HTT but does show support for interaction with MAOA in men. It also provides new evidence that variation in the DRD4 gene modifies an individual's response to the exposure, with individuals with no 7-repeats found to have a muted response.

  14. Is there any evidence that cerebral protection is beneficial? Experimental data.

    PubMed

    Macdonald, S

    2006-04-01

    This article presents the available experimental data from the world literature on the use of cerebral protection devices during carotid artery stenting (CAS). Clinical studies relying on surrogate markers of cerebral embolisation in place of neurological event rate as primary outcome measures are evaluated alongside bench-top and animal studies. These surrogate markers include evaluations of outcomes using procedural transcranial Doppler (TCD) and diffusion-weighted magnetic resonance imaging of brain (DWI). Pathological analyses of debris retrieved from in-vivo analyses of protection devices are also included in this review because although the focus of these studies was primarily clinical, the laboratory data will be preferentially presented and it provides interesting insights. It can be shown that each of the three philosophies of cerebral protection, namely flow arrest (proximal or distal), flow reversal and distal filtration is capable of the entrapment of sizeable debris that would logically threaten devastating stroke if it embolized to the brain. Whilst balloon occlusion significantly reduces the procedural microembolic load (particles less than 60 mm) and flow reversal may be the first means to entirely eliminate it, filters may be associated with increased microembolization. This has been described by some workers as controlled embolization. Certainly, particles smaller than the pore size of currently available filters (60-140 mm) will readily evade capture due to filter periflow and through-flow. There is evidence to suggest that tens of thousands of particles of this size may be released during CAS and there is some evidence that this may be associated with more new white lesions on DWI of brain. The clinical consequences of this controlled embolization however, remain unclear and sophisticated neuropsychometric test batteries may need to be applied at later time points to detect subtle injury that may be compounded by a late inflammatory response

  15. Physics of human cooperation: experimental evidence and theoretical models

    NASA Astrophysics Data System (ADS)

    Sánchez, Angel

    2018-02-01

    In recent years, many physicists have used evolutionary game theory combined with a complex systems perspective in an attempt to understand social phenomena and challenges. Prominent among such phenomena is the issue of the emergence and sustainability of cooperation in a networked world of selfish or self-focused individuals. The vast majority of research done by physicists on these questions is theoretical, and is almost always posed in terms of agent-based models. Unfortunately, more often than not such models ignore a number of facts that are well established experimentally, and are thus rendered irrelevant to actual social applications. I here summarize some of the facts that any realistic model should incorporate and take into account, discuss important aspects underlying the relation between theory and experiments, and discuss future directions for research based on the available experimental knowledge.

  16. Experimental evidence of quantum radiation reaction in aligned crystals.

    PubMed

    Wistisen, Tobias N; Di Piazza, Antonino; Knudsen, Helge V; Uggerhøj, Ulrik I

    2018-02-23

    Quantum radiation reaction is the influence of multiple photon emissions from a charged particle on the particle's dynamics, characterized by a significant energy-momentum loss per emission. Here we report experimental radiation emission spectra from ultrarelativistic positrons in silicon in a regime where quantum radiation reaction effects dominate the positron's dynamics. Our analysis shows that while the widely used quantum approach is overall the best model, it does not completely describe all the data in this regime. Thus, these experimental findings may prompt seeking more generally valid methods to describe quantum radiation reaction. This experiment is a fundamental test of quantum electrodynamics in a regime where the dynamics of charged particles is strongly influenced not only by the external electromagnetic fields but also by the radiation field generated by the charges themselves and where each photon emission may significantly reduce the energy of the charge.

  17. Experimental evidence for the cardioprotective effects of red wine

    PubMed Central

    Das, Samarjit; Santani, Dev D; Dhalla, Naranjan S

    2007-01-01

    Both epidemiological and experimental studies have revealed that intake of wine, particularly red wine, in moderation protects cardiovascular health; however, the experimental basis for such an action is not fully understood. Because all types of red wine contain varying amounts of alcohol and antioxidants, it is likely that the cardioprotective effect of red wine is due to both these constituents. In view of its direct action on the vascular smooth muscle cells, alcohol may produce coronary vasodilation in addition to attenuating oxidative stress by its action on the central nervous system. The antioxidant components of red wine may provide cardioprotection by their ability to reduce oxidative stress in the heart under different pathological conditions. Mild-to-moderate red wine consumption improves cardiac function in the ischemic myocardium through the protection of endothelial function, the expression of several cardioprotective oxidative stress-inducible proteins, as well as the activation of adenosine receptors and nitrous oxide synthase mechanisms. PMID:18650973

  18. Experimental evidence for the cardioprotective effects of red wine.

    PubMed

    Das, Samarjit; Santani, Dev D; Dhalla, Naranjan S

    2007-01-01

    Both epidemiological and experimental studies have revealed that intake of wine, particularly red wine, in moderation protects cardiovascular health; however, the experimental basis for such an action is not fully understood. Because all types of red wine contain varying amounts of alcohol and antioxidants, it is likely that the cardioprotective effect of red wine is due to both these constituents. In view of its direct action on the vascular smooth muscle cells, alcohol may produce coronary vasodilation in addition to attenuating oxidative stress by its action on the central nervous system. The antioxidant components of red wine may provide cardioprotection by their ability to reduce oxidative stress in the heart under different pathological conditions. Mild-to-moderate red wine consumption improves cardiac function in the ischemic myocardium through the protection of endothelial function, the expression of several cardioprotective oxidative stress-inducible proteins, as well as the activation of adenosine receptors and nitrous oxide synthase mechanisms.

  19. Photorespiratory Bypasses Lead to Increased Growth in Arabidopsis thaliana: Are Predictions Consistent with Experimental Evidence?

    PubMed Central

    Basler, Georg; Küken, Anika; Fernie, Alisdair R.; Nikoloski, Zoran

    2016-01-01

    Arguably, the biggest challenge of modern plant systems biology lies in predicting the performance of plant species, and crops in particular, upon different intracellular and external perturbations. Recently, an increased growth of Arabidopsis thaliana plants was achieved by introducing two different photorespiratory bypasses via metabolic engineering. Here, we investigate the extent to which these findings match the predictions from constraint-based modeling. To determine the effect of the employed metabolic network model on the predictions, we perform a comparative analysis involving three state-of-the-art metabolic reconstructions of A. thaliana. In addition, we investigate three scenarios with respect to experimental findings on the ratios of the carboxylation and oxygenation reactions of Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). We demonstrate that the condition-dependent growth phenotypes of one of the engineered bypasses can be qualitatively reproduced by each reconstruction, particularly upon considering the additional constraints with respect to the ratio of fluxes for the RuBisCO reactions. Moreover, our results lend support for the hypothesis of a reduced photorespiration in the engineered plants, and indicate that specific changes in CO2 exchange as well as in the proxies for co-factor turnover are associated with the predicted growth increase in the engineered plants. We discuss our findings with respect to the structure of the used models, the modeling approaches taken, and the available experimental evidence. Our study sets the ground for investigating other strategies for increase of plant biomass by insertion of synthetic reactions. PMID:27092301

  20. Genetic evidence for involvement of classical complement pathway in induction of experimental autoimmune myasthenia gravis.

    PubMed

    Tüzün, Erdem; Scott, Benjamin G; Goluszko, Elzbieta; Higgs, Stephen; Christadoss, Premkumar

    2003-10-01

    Abs to acetylcholine receptor (AChR) and complement are the major constituents of pathogenic events causing neuromuscular junction destruction in both myasthenia gravis (MG) and experimental autoimmune MG (EAMG). To analyze the differential roles of the classical vs alternative complement pathways in EAMG induction, we immunized C3(-/-), C4(-/-), C3(+/-), and C4(+/-) mice and their control littermates (C3(+/+) and C4(+/+) mice) with AChR in CFA. C3(-/-) and C4(-/-) mice were resistant to disease, whereas mice heterozygous for C3 or C4 displayed intermediate susceptibility. Although C3(-/-) and C4(-/-) mice had anti-AChR Abs in their sera, anti-AChR IgG production by C3(-/-) mice was significantly suppressed. Both C3(-/-) and C4(-/-) mice had reduced levels of B cells and increased expression of apoptotis inducers (Fas ligand, CD69) and apoptotic cells in lymph nodes. Immunofluorescence studies showed that the neuromuscular junction of C3(-/-) and C4(-/-) mice lacked C3 or membrane attack complex deposits, despite having IgG deposits, thus providing in vivo evidence for the incapacity of anti-AChR IgGs to induce full-blown EAMG without the aid of complements. The data provide the first direct genetic evidence for the classical complement pathway in the induction of EAMG induced by AChR immunization. Accordingly, severe MG and other Ab- and complement-mediated diseases could be effectively treated by inhibiting C4, thus leaving the alternative complement pathway intact.

  1. Experimental evidence that RNA recombination occurs in the Japanese encephalitis virus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chuang, C.-K.; Chen, W.-J., E-mail: wjchen@mail.cgu.edu.t; Department of Public Health and Parasitology, Chang Gung University, Kwei-San, Tao-Yuan 33332, Taiwan

    2009-11-25

    Due to the lack of a proofreading function and error-repairing ability of genomic RNA, accumulated mutations are known to be a force driving viral evolution in the genus Flavivirus, including the Japanese encephalitis (JE) virus. Based on sequencing data, RNA recombination was recently postulated to be another factor associated with genomic variations in these viruses. We herein provide experimental evidence to demonstrate the occurrence of RNA recombination in the JE virus using two local pure clones (T1P1-S1 and CJN-S1) respectively derived from the local strains, T1P1 and CJN. Based on results from a restriction fragment length polymorphism (RFLP) assay onmore » the C/preM junction comprising a fragment of 868 nucleotides (nt 10-877), the recombinant progeny virus was primarily formed in BHK-21 cells that had been co-infected with the two clones used in this study. Nine of 20 recombinant forms of the JE virus had a crossover in the nt 123-323 region. Sequencing data derived from these recombinants revealed that no nucleotide deletion or insertion occurred in this region favoring crossovers, indicating that precisely, not aberrantly, homologous recombination was involved. With site-directed mutagenesis, three stem-loop secondary structures were destabilized and re-stabilized in sequence, leading to changes in the frequency of recombination. This suggests that the conformation, not the free energy, of the secondary structure is important in modulating RNA recombination of the virus. It was concluded that because RNA recombination generates genetic diversity in the JE virus, this must be considered particularly in studies of viral evolution, epidemiology, and possible vaccine safety.« less

  2. Quasi-experimental study designs series-paper 11: supporting the production and use of health systems research syntheses that draw on quasi-experimental study designs.

    PubMed

    Lavis, John N; Bärnighausen, Till; El-Jardali, Fadi

    2017-09-01

    To describe the infrastructure available to support the production of policy-relevant health systems research syntheses, particularly those incorporating quasi-experimental evidence, and the tools available to support the use of these syntheses. Literature review. The general challenges associated with the available infrastructure include their sporadic nature or limited coverage of issues and countries, whereas the specific ones related to policy-relevant syntheses of quasi-experimental evidence include the lack of mechanism to register synthesis titles and scoping review protocols, the limited number of groups preparing user-friendly summaries, and the difficulty of finding quasi-experimental studies for inclusion in rapid syntheses and research syntheses more generally. Although some new tools have emerged in recent years, such as guidance workbooks and citizen briefs and panels, challenges related to using available tools to support the use of policy-relevant syntheses of quasi-experimental evidence arise from such studies potentially being harder for policymakers and stakeholders to commission and understand. Policymakers, stakeholders, and researchers need to expand the coverage and institutionalize the use of the available infrastructure and tools to support the use of health system research syntheses containing quasi-experimental evidence. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. The fishermen were right: experimental evidence for tributary refuge hypothesis during floods.

    PubMed

    Koizumi, Itsuro; Kanazawa, Yukiyo; Tanaka, Yuuki

    2013-05-01

    Fishermen often anecdotally report an unexpected increase of fish caught in small tributary streams during floods, presumably due to refuge-seeking behavior from the main stem. From a population perspective, this implies the significance of refuge habitats and connectivity for population viability against natural disturbances. Despite the plausibility, however, surprisingly few studies have examined the tributary refuge hypothesis, mainly due to the difficulty in field survey during floods. Here, we made use of a large-scale controlled flood to assess whether fishes move into tributaries during flooding in the main stem. A planned water release from the Satsunai River Dam located on Hokkaido Island in Japan rapidly increased the main stem discharge by more than 20-fold. Before, during, and after flooding censuses in four tributaries provided evidence of the refuge-seeking behavior of fishes from the main stem. For example, more than 10 Dolly Varden char, a salmonid fish, were caught in a tributary during the flood, even though almost no individuals were captured before or after the flood. The fish responded immediately to the flooding, suggesting the need for studies during disturbances. In addition, the likelihood of refuge movements varied among tributaries, suggesting the importance of local environmental differences between tributary and the main stem habitats. This is the first study to experimentally confirm the tributary refuge hypothesis, and underscores the roles of habitat diversity and connectivity during disturbances, even though some habitats are not used during normal conditions.

  4. The Experimental Design Ability Test (EDAT)

    ERIC Educational Resources Information Center

    Sirum, Karen; Humburg, Jennifer

    2011-01-01

    Higher education goals include helping students develop evidence based reasoning skills; therefore, scientific thinking skills such as those required to understand the design of a basic experiment are important. The Experimental Design Ability Test (EDAT) measures students' understanding of the criteria for good experimental design through their…

  5. Experimental evidence of human recreational disturbance effects on bird-territory establishment.

    PubMed

    Bötsch, Yves; Tablado, Zulima; Jenni, Lukas

    2017-07-12

    The worldwide increase in human outdoor activities raises concerns for wildlife. Human disturbances, even at low levels, are likely to impact species during sensitive periods of the annual cycle. However, experimental studies during the putative sensitive period of territory establishment of birds which not only investigate low disturbance levels, but which also exclude the effect of habitat modification (e.g. walking trails) are lacking. Here, we experimentally disturbed birds in forest plots by walking through twice a day during territory establishment. Later we compared the breeding bird community of experimentally disturbed plots with that of undisturbed control plots. We discovered that the number of territories (-15.0%) and species richness (-15.2%) in disturbed plots were substantially reduced compared with control plots. Species most affected included those sensitive to human presence (assessed by flight-initiation distances), open-cup nesters and above-ground foragers. Long-distance migrants, however, were unaffected due to their arrival after experimental disturbance took place. These findings highlight how territory establishment is a sensitive period for birds, when even low levels of human recreation may be perceived as threatening, and alter settlement decisions. This can have important implications for the conservation of species, which might go unnoticed when focusing only on already established birds. © 2017 The Author(s).

  6. Quasi-experimental study designs series-paper 4: uses and value.

    PubMed

    Bärnighausen, Till; Tugwell, Peter; Røttingen, John-Arne; Shemilt, Ian; Rockers, Peter; Geldsetzer, Pascal; Lavis, John; Grimshaw, Jeremy; Daniels, Karen; Brown, Annette; Bor, Jacob; Tanner, Jeffery; Rashidian, Arash; Barreto, Mauricio; Vollmer, Sebastian; Atun, Rifat

    2017-09-01

    Quasi-experimental studies are increasingly used to establish causal relationships in epidemiology and health systems research. Quasi-experimental studies offer important opportunities to increase and improve evidence on causal effects: (1) they can generate causal evidence when randomized controlled trials are impossible; (2) they typically generate causal evidence with a high degree of external validity; (3) they avoid the threats to internal validity that arise when participants in nonblinded experiments change their behavior in response to the experimental assignment to either intervention or control arm (such as compensatory rivalry or resentful demoralization); (4) they are often well suited to generate causal evidence on long-term health outcomes of an intervention, as well as nonhealth outcomes such as economic and social consequences; and (5) they can often generate evidence faster and at lower cost than experiments and other intervention studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. The fungal colonisation of rock-art caves: experimental evidence.

    PubMed

    Jurado, Valme; Fernandez-Cortes, Angel; Cuezva, Soledad; Laiz, Leonila; Cañaveras, Juan Carlos; Sanchez-Moral, Sergio; Saiz-Jimenez, Cesareo

    2009-09-01

    The conservation of rock-art paintings in European caves is a matter of increasing interest. This derives from the bacterial colonisation of Altamira Cave, Spain and the recent fungal outbreak of Lascaux Cave, France-both included in the UNESCO World Heritage List. Here, we show direct evidence of a fungal colonisation of rock tablets in a testing system exposed in Altamira Cave. After 2 months, the tablets, previously sterilised, were heavily colonised by fungi and bacteria. Most fungi isolated were labelled as entomopathogens, while the bacteria were those regularly identified in the cave. Rock colonisation was probably promoted by the dissolved organic carbon supplied with the dripping and condensation waters and favoured by the displacement of aerosols towards the interior of the cave, which contributed to the dissemination of microorganisms. The role of arthropods in the dispersal of spores may also help in understanding fungal colonisation. This study evidences the fragility of rock-art caves and demonstrates that microorganisms can easily colonise bare rocks and materials introduced into the cavity.

  8. Experimental evidence that mycorrhizal nitrogen strategies affect soil carbon

    Treesearch

    Nina Wurzburger; E. N. Jack Brookshire

    2017-01-01

    Most land plants acquire nitrogen (N) through associations with arbuscular (AM) and ectomycorrhizal (ECM) fungi, but these symbionts employ contrasting strategies for N acquisition, which may lead to different stocks of soil carbon (C). We experimentally test this hypothesis with a mesocosm system where AM and ECM tree seedling roots, or their hyphae only, could access...

  9. Experimental evidence for circular inference in schizophrenia.

    PubMed

    Jardri, Renaud; Duverne, Sandrine; Litvinova, Alexandra S; Denève, Sophie

    2017-01-31

    Schizophrenia (SCZ) is a complex mental disorder that may result in some combination of hallucinations, delusions and disorganized thinking. Here SCZ patients and healthy controls (CTLs) report their level of confidence on a forced-choice task that manipulated the strength of sensory evidence and prior information. Neither group's responses can be explained by simple Bayesian inference. Rather, individual responses are best captured by a model with different degrees of circular inference. Circular inference refers to a corruption of sensory data by prior information and vice versa, leading us to 'see what we expect' (through descending loops), to 'expect what we see' (through ascending loops) or both. Ascending loops are stronger for SCZ than CTLs and correlate with the severity of positive symptoms. Descending loops correlate with the severity of negative symptoms. Both loops correlate with disorganized symptoms. The findings suggest that circular inference might mediate the clinical manifestations of SCZ.

  10. Experimental evidence for circular inference in schizophrenia

    NASA Astrophysics Data System (ADS)

    Jardri, Renaud; Duverne, Sandrine; Litvinova, Alexandra S.; Denève, Sophie

    2017-01-01

    Schizophrenia (SCZ) is a complex mental disorder that may result in some combination of hallucinations, delusions and disorganized thinking. Here SCZ patients and healthy controls (CTLs) report their level of confidence on a forced-choice task that manipulated the strength of sensory evidence and prior information. Neither group's responses can be explained by simple Bayesian inference. Rather, individual responses are best captured by a model with different degrees of circular inference. Circular inference refers to a corruption of sensory data by prior information and vice versa, leading us to `see what we expect' (through descending loops), to `expect what we see' (through ascending loops) or both. Ascending loops are stronger for SCZ than CTLs and correlate with the severity of positive symptoms. Descending loops correlate with the severity of negative symptoms. Both loops correlate with disorganized symptoms. The findings suggest that circular inference might mediate the clinical manifestations of SCZ.

  11. Strategic sophistication of individuals and teams. Experimental evidence

    PubMed Central

    Sutter, Matthias; Czermak, Simon; Feri, Francesco

    2013-01-01

    Many important decisions require strategic sophistication. We examine experimentally whether teams act more strategically than individuals. We let individuals and teams make choices in simple games, and also elicit first- and second-order beliefs. We find that teams play the Nash equilibrium strategy significantly more often, and their choices are more often a best response to stated first order beliefs. Distributional preferences make equilibrium play less likely. Using a mixture model, the estimated probability to play strategically is 62% for teams, but only 40% for individuals. A model of noisy introspection reveals that teams differ from individuals in higher order beliefs. PMID:24926100

  12. Physiology and pathology of saccades and gaze holding.

    PubMed

    Shaikh, Aasef G; Ghasia, Fatema F

    2013-01-01

    Foveation is the fundamental requirement for clear vision. Saccades rapidly shift the gaze to the interesting target while gaze holding ensures foveation of the desired object. We will review the pertinent physiology of saccades and gaze holding and their pathophysiology leading to saccadic oscillations, slow saccades, saccadic dysmetria, and nystagmus. Motor commands for saccades are generated at multiple levels of the neuraxis. The frontal and parietal eye field send saccadic commands to the superior colliculus. Latter then projects to the brain-stem saccadic burst generator. The brain-stem burst generators guarantee optimum signal to ensure rapid saccadic velocity, while the neural integrator, by mathematically integrating the saccadic pulse, facilitates stable gaze holding. Reciprocal innervations that ensure rapid saccadic velocity are prone to inherent instability leading to saccadic oscillations. In contrast, suboptimal function of the burst generators causes slow saccades. Impaired error correction, either at the cerebellum or the inferior olive, leads to impaired saccade adaptation and ultimately saccadic dysmetria and oculopalatal tremor. Impairment in the function of neural integrator causes nystagmus. Neurophysiology of saccades, gaze holding, and their deficits are well recognized. These principles can be implemented to define novel therapeutic and rehabilitation approaches.

  13. Experimental evidence for circular inference in schizophrenia

    PubMed Central

    Jardri, Renaud; Duverne, Sandrine; Litvinova, Alexandra S; Denève, Sophie

    2017-01-01

    Schizophrenia (SCZ) is a complex mental disorder that may result in some combination of hallucinations, delusions and disorganized thinking. Here SCZ patients and healthy controls (CTLs) report their level of confidence on a forced-choice task that manipulated the strength of sensory evidence and prior information. Neither group's responses can be explained by simple Bayesian inference. Rather, individual responses are best captured by a model with different degrees of circular inference. Circular inference refers to a corruption of sensory data by prior information and vice versa, leading us to ‘see what we expect' (through descending loops), to ‘expect what we see' (through ascending loops) or both. Ascending loops are stronger for SCZ than CTLs and correlate with the severity of positive symptoms. Descending loops correlate with the severity of negative symptoms. Both loops correlate with disorganized symptoms. The findings suggest that circular inference might mediate the clinical manifestations of SCZ. PMID:28139642

  14. Observational Versus Experimental Studies: What’s the Evidence for a Hierarchy?

    PubMed Central

    Concato, John

    2004-01-01

    Summary: The tenets of evidence-based medicine include an emphasis on hierarchies of research design (i.e., study architecture). Often, a single randomized, controlled trial is considered to provide “truth,” whereas results from any observational study are viewed with suspicion. This paper describes information that contradicts and discourages such a rigid approach to evaluating the quality of research design. Unless a more balanced strategy evolves, new claims of methodological authority may be just as problematic as the traditional claims of medical authority that have been criticized by proponents of evidence-based medicine. PMID:15717036

  15. Predicting the Unpredictable: 75 Years of Experimental Evidence

    NASA Astrophysics Data System (ADS)

    Radin, Dean I.

    2011-11-01

    From time immemorial, people have reported foreknowledge of future events. To determine whether such experiences are best understood via conventional explanations, or whether a retrocausal phenomenon might be involved in some instances, researchers have conducted hundreds of controlled laboratory experiments over the past 75 years. These studies fall into four general classes, and each class has generated repeatable evidence consistent with retrocausation. The statistical results for a class of forced-choice studies is associated with odds against chance of about 1024; for a class of free-response studies, odds about 1020; for psychophysiological-based studies, odds about 1017; and for implicit decision studies, odds about 1010. Effect sizes observed in the latter three classes are nearly identical, indicating replication of similar underlying effects. These effects are also in close agreement with the average effect size across 25,000 conventional social psychology experiments conducted over the last century, suggesting that retrocausal phenomena may not be especially unique, at least not in terms of the magnitude of effect. Bayesian analyses of the most recent classes of experiments confirm that the evidence is strongly in favor of a genuine effect, with Bayes Factors ranging from 13,669 to 1 for implicit decision experiments, to 2.9×1013 to 1 for psychophysiological designs. For the two most recent classes of studies examining retrocausal effects via unconscious physiological or behavioral measures, 85 of 101 studies (84%) reported by 25 different laboratories from the United States, Italy, Spain, Holland, Austria, Sweden, England, Scotland, Iran, Japan, and Australia, have produced results in the direction predicted by a retrocausal effect (odds against chance = 1.3×1012, via a sign test). Assessment of the methodologies used in these studies has not identified plausible conventional alternatives for the observed outcomes, suggesting the existence of a

  16. Experimental Evidence for the Role of Intonation in Evidential Marking.

    PubMed

    Vanrell, Maria Del Mar; Armstrong, Meghan E; Prieto, Pilar

    2017-06-01

    This paper investigates the role of intonation in the marking of directly-perceived information in Majorcan Catalan polar questions. We conducted a perception experiment in which a total of 72 participants were introduced to a set of twins who were exposed to different types of evidence for a given p(roposition). One twin inferred p based on direct sensory information (via one of the five senses), while the other had been told that p by a third party, that is, reported information. Participants listened to a set of discourse contexts that ended in critical stimuli with three attested combinations of particle/intonation in this variety of Catalan: (1) polar questions produced with a falling nuclear contour ¡H+L* L%; (2) polar questions headed with the particle que 'that' produced with ¡H+L* L%; and (3) polar questions headed with the particle que and produced with a rise-fall L+H* L%. After hearing the stimulus, participants had to decide which of the twins had uttered the question-the one who inferred a proposition ( p) based on direct sensory information or the one who had been told p by a third party. The results show that listeners very consistently associate the que + L+H* L% combination with inferences drawn from direct sensory evidence as opposed to reported evidence. This shows that particles may work in tandem with intonation to convey the information source. Importantly, we show that intonation is a part of grammar that may be recruited for evidential strategies.

  17. The effects of prosocial video games on prosocial behaviors: international evidence from correlational, longitudinal, and experimental studies.

    PubMed

    Gentile, Douglas A; Anderson, Craig A; Yukawa, Shintaro; Ihori, Nobuko; Saleem, Muniba; Ming, Lim Kam; Shibuya, Akiko; Liau, Albert K; Khoo, Angeline; Bushman, Brad J; Rowell Huesmann, L; Sakamoto, Akira

    2009-06-01

    Although dozens of studies have documented a relationship between violent video games and aggressive behaviors, very little attention has been paid to potential effects of prosocial games. Theoretically, games in which game characters help and support each other in nonviolent ways should increase both short-term and long-term prosocial behaviors. We report three studies conducted in three countries with three age groups to test this hypothesis. In the correlational study, Singaporean middle-school students who played more prosocial games behaved more prosocially. In the two longitudinal samples of Japanese children and adolescents, prosocial game play predicted later increases in prosocial behavior. In the experimental study, U.S. undergraduates randomly assigned to play prosocial games behaved more prosocially toward another student. These similar results across different methodologies, ages, and cultures provide robust evidence of a prosocial game content effect, and they provide support for the General Learning Model.

  18. The Effects of Prosocial Video Games on Prosocial Behaviors: International Evidence from Correlational, Longitudinal, and Experimental Studies

    PubMed Central

    Gentile, Douglas A.; Anderson, Craig A.; Yukawa, Shintaro; Ihori, Nobuko; Saleem, Muniba; Ming, Lim Kam; Shibuya, Akiko; Liau, Albert K.; Khoo, Angeline; Bushman, Brad J.; Huesmann, L. Rowell; Sakamoto, Akira

    2009-01-01

    Although dozens of studies have documented a relation between violent video games and aggressive behaviors, very little attention has been paid to potential effects of prosocial games. Theoretically, games in which game characters help and support each other in nonviolent ways should increase both short-term and long-term prosocial behaviors. We report three studies conducted in three countries with three age groups to test this hypothesis. In the correlational study, Singaporean middle-school students who played more prosocial games behaved more prosocially. In the two longitudinal samples of Japanese children and adolescents, prosocial game play predicted later increases in prosocial behavior. In the experimental study, U.S. undergraduates randomly assigned to play prosocial games behaved more prosocially toward another student. These similar results across different methodologies, ages, and cultures provide robust evidence a prosocial game content effect, and provide support for the General Learning Model. PMID:19321812

  19. Coincidence-enhanced stochastic resonance: experimental evidence challenges the psychophysical theory behind stochastic resonance.

    PubMed

    Perez, Claudio A; Cohn, Theodore E; Medina, Leonel E; Donoso, José R

    2007-08-31

    Stochastic resonance (SR) is the counterintuitive phenomenon in which noise enhances detection of sub-threshold stimuli. The SR psychophysical threshold theory establishes that the required amplitude to exceed the sensory threshold barrier can be reached by adding noise to a sub-threshold stimulus. The aim of this study was to test the SR theory by comparing detection results from two different randomly-presented stimulus conditions. In the first condition, optimal noise was present during the whole attention interval; in the second, the optimal noise was restricted to the same time interval as the stimulus. SR threshold theory predicts no difference between the two conditions because noise helps the sub-threshold stimulus to reach threshold in both cases. The psychophysical experimental method used a 300 ms rectangular force pulse as a stimulus within an attention interval of 1.5 s, applied to the index finger of six human subjects in the two distinct conditions. For all subjects we show that in the condition in which the noise was present only when synchronized with the stimulus, detection was better (p<0.05) than in the condition in which the noise was delivered throughout the attention interval. These results provide the first direct evidence that SR threshold theory is incomplete and that a new phenomenon has been identified, which we call Coincidence-Enhanced Stochastic Resonance (CESR). We propose that CESR might occur because subject uncertainty is reduced when noise points at the same temporal window as the stimulus.

  20. Experimental evidence for partial spatial coherence in imaging Mueller polarimetry.

    PubMed

    Ossikovski, Razvigor; Arteaga, Oriol; Yoo, Sang Hyuk; Garcia-Caurel, Enric; Hingerl, Kurt

    2017-11-15

    We demonstrate experimentally the validity of the partial spatial coherence formalism in Mueller polarimetry and show that, in a finite spatial resolution experiment, the measured response is obtained through convolving the theoretical one with the instrument function. The reported results are of primary importance for Mueller imaging systems.

  1. Discriminating evidence accumulation from urgency signals in speeded decision making.

    PubMed

    Hawkins, Guy E; Wagenmakers, Eric-Jan; Ratcliff, Roger; Brown, Scott D

    2015-07-01

    The dominant theoretical paradigm in explaining decision making throughout both neuroscience and cognitive science is known as “evidence accumulation”--The core idea being that decisions are reached by a gradual accumulation of noisy information. Although this notion has been supported by hundreds of experiments over decades of study, a recent theory proposes that the fundamental assumption of evidence accumulation requires revision. The "urgency gating" model assumes decisions are made without accumulating evidence, using only moment-by-moment information. Under this assumption, the successful history of evidence accumulation models is explained by asserting that the two models are mathematically identical in standard experimental procedures. We demonstrate that this proof of equivalence is incorrect, and that the models are not identical, even when both models are augmented with realistic extra assumptions. We also demonstrate that the two models can be perfectly distinguished in realistic simulated experimental designs, and in two real data sets; the evidence accumulation model provided the best account for one data set, and the urgency gating model for the other. A positive outcome is that the opposing modeling approaches can be fruitfully investigated without wholesale change to the standard experimental paradigms. We conclude that future research must establish whether the urgency gating model enjoys the same empirical support in the standard experimental paradigms that evidence accumulation models have gathered over decades of study. Copyright © 2015 the American Physiological Society.

  2. Standardized description of scientific evidence using the Evidence Ontology (ECO)

    PubMed Central

    Chibucos, Marcus C.; Mungall, Christopher J.; Balakrishnan, Rama; Christie, Karen R.; Huntley, Rachael P.; White, Owen; Blake, Judith A.; Lewis, Suzanna E.; Giglio, Michelle

    2014-01-01

    The Evidence Ontology (ECO) is a structured, controlled vocabulary for capturing evidence in biological research. ECO includes diverse terms for categorizing evidence that supports annotation assertions including experimental types, computational methods, author statements and curator inferences. Using ECO, annotation assertions can be distinguished according to the evidence they are based on such as those made by curators versus those automatically computed or those made via high-throughput data review versus single test experiments. Originally created for capturing evidence associated with Gene Ontology annotations, ECO is now used in other capacities by many additional annotation resources including UniProt, Mouse Genome Informatics, Saccharomyces Genome Database, PomBase, the Protein Information Resource and others. Information on the development and use of ECO can be found at http://evidenceontology.org. The ontology is freely available under Creative Commons license (CC BY-SA 3.0), and can be downloaded in both Open Biological Ontologies and Web Ontology Language formats at http://code.google.com/p/evidenceontology. Also at this site is a tracker for user submission of term requests and questions. ECO remains under active development in response to user-requested terms and in collaborations with other ontologies and database resources. Database URL: Evidence Ontology Web site: http://evidenceontology.org PMID:25052702

  3. Theoretical and experimental evidence of non-symmetric doubly localized rogue waves.

    PubMed

    He, Jingsong; Guo, Lijuan; Zhang, Yongshuai; Chabchoub, Amin

    2014-11-08

    We present determinant expressions for vector rogue wave (RW) solutions of the Manakov system, a two-component coupled nonlinear Schrödinger (NLS) equation. As a special case, we generate a family of exact and non-symmetric RW solutions of the NLS equation up to third order, localized in both space and time. The derived non-symmetric doubly localized second-order solution is generated experimentally in a water wave flume for deep-water conditions. Experimental results, confirming the characteristic non-symmetric pattern of the solution, are in very good agreement with theory as well as with numerical simulations, based on the modified NLS equation, known to model accurately the dynamics of weakly nonlinear wave packets in deep water.

  4. Exercise and physical activity in mental disorders: clinical and experimental evidence.

    PubMed

    Zschucke, Elisabeth; Gaudlitz, Katharina; Ströhle, Andreas

    2013-01-01

    Several epidemiological studies have shown that exercise (EX) and physical activity (PA) can prevent or delay the onset of different mental disorders, and have therapeutic benefits when used as sole or adjunct treatment in mental disorders. This review summarizes studies that used EX interventions in patients with anxiety, affective, eating, and substance use disorders, as well as schizophrenia and dementia/mild cognitive impairment. Despite several decades of clinical evidence with EX interventions, controlled studies are sparse in most disorder groups. Preliminary evidence suggests that PA/EX can induce improvements in physical, subjective and disorder-specific clinical outcomes. Potential mechanisms of action are discussed, as well as implications for psychiatric research and practice.

  5. Further Evidence for the Efficacy of an Evidence-Based, Small Group, Literacy Intervention Program for Young Struggling Readers

    ERIC Educational Resources Information Center

    Wheldall, Kevin; Wheldall, Robyn; Madelaine, Alison; Reynolds, Meree; Arakelian, Sarah

    2017-01-01

    An earlier series of pilot studies and small-scale experimental studies had previously provided some evidence for the efficacy of a small group early literacy intervention program for young struggling readers. The present paper provides further evidence for efficacy based on a much larger sample of young, socially disadvantaged, at-risk readers.…

  6. Experimental Evaluations of Elementary Science Programs: A Best-Evidence Synthesis

    ERIC Educational Resources Information Center

    Slavin, Robert E.; Lake, Cynthia; Hanley, Pam; Thurston, Allen

    2014-01-01

    This article presents a systematic review of research on the achievement outcomes of all types of approaches to teaching science in elementary schools. Study inclusion criteria included use of randomized or matched control groups, a study duration of at least 4 weeks, and use of achievement measures independent of the experimental treatment. A…

  7. Smectite clays in Mars soil - Evidence for their presence and role in Viking biology experimental results

    NASA Technical Reports Server (NTRS)

    Banin, A.; Rishpon, J.

    1979-01-01

    Evidence for the presence of smectite clays in Martian soils is reviewed and results of experiments with certain active clays simulating the Viking biology experiments are reported. Analyses of Martian soil composition by means of X-ray fluorescence spectrometry and dust storm spectroscopy and Martian geological history strongly suggest the presence of a mixture of weathered ferro-silicate minerals, mainly nontronite and montmorillonite, accompanied by soluble sulphate salts, as major constituents. Samples of montmorillonite and nontronite incubated with (C-14)-formate or the radioactive nutrient medium solution used in the Viking Labeled Release experiment, were found to produce patterns of release of radioactive gas very similar to those observed in the Viking experiments, indicating the iron-catalyzed decomposition of formate as the reaction responsible for the Viking results. The experimental results of Hubbard (1979) simulating the results of the Viking Pyrolytic Release experiment using iron montmorillonites are pointed out, and it is concluded that many of the results of the Viking biology experiments can be explained in terms of the surface activity of smectite clays in catalysis and adsorption.

  8. A young woman with seizures and psychosis

    PubMed Central

    Naha, Sowjanya; Naha, Kushal; Hande, H Manjunath; Vivek, Ganapathiraman

    2014-01-01

    We present a case of a 24-year-old woman with abnormal behaviour of recent onset. She had been diagnosed previously with epilepsy and had been started on antiepileptic medication. Clinical examination confirmed features of psychosis including paranoid delusions and auditory hallucination. Neurological examination showed nystagmus and dysmetria. Further evaluation revealed the underlying cause for her symptoms. She responded promptly to appropriate therapy with complete resolution of psychosis. PMID:25008334

  9. Experimental evidence of mobility enhancement in short-channel ultra-thin body double-gate MOSFETs by magnetoresistance technique

    NASA Astrophysics Data System (ADS)

    Chaisantikulwat, W.; Mouis, M.; Ghibaudo, G.; Cristoloveanu, S.; Widiez, J.; Vinet, M.; Deleonibus, S.

    2007-11-01

    Double-gate transistor with ultra-thin body (UTB) has proved to offer advantages over bulk device for high-speed, low-power applications. There is thus a strong need to obtain an accurate understanding of carrier transport and mobility in such device. In this work, we report for the first time an experimental evidence of mobility enhancement in UTB double-gate (DG) MOSFETs using magnetoresistance mobility extraction technique. Mobility in planar DG transistor operating in single- and double-gate mode is compared. The influence of different scattering mechanisms in the channel is also investigated by obtaining mobility values at low temperatures. The results show a clear mobility improvement in double-gate mode compared to single-gate mode mobility at the same inversion charge density. This is explained by the role of volume inversion in ultra-thin body transistor operating in DG mode. Volume inversion is found to be especially beneficial in terms of mobility gain at low-inversion densities.

  10. Theoretical and experimental evidence of non-symmetric doubly localized rogue waves

    PubMed Central

    He, Jingsong; Guo, Lijuan; Zhang, Yongshuai; Chabchoub, Amin

    2014-01-01

    We present determinant expressions for vector rogue wave (RW) solutions of the Manakov system, a two-component coupled nonlinear Schrödinger (NLS) equation. As a special case, we generate a family of exact and non-symmetric RW solutions of the NLS equation up to third order, localized in both space and time. The derived non-symmetric doubly localized second-order solution is generated experimentally in a water wave flume for deep-water conditions. Experimental results, confirming the characteristic non-symmetric pattern of the solution, are in very good agreement with theory as well as with numerical simulations, based on the modified NLS equation, known to model accurately the dynamics of weakly nonlinear wave packets in deep water. PMID:25383023

  11. The role of barrier membranes for guided bone regeneration and restoration of large bone defects: current experimental and clinical evidence

    PubMed Central

    2012-01-01

    Treatment of large bone defects represents a great challenge in orthopedic and craniomaxillofacial surgery. Although there are several methods for bone reconstruction, they all have specific indications and limitations. The concept of using barrier membranes for restoration of bone defects has been developed in an effort to simplify their treatment by offering a sinlge-staged procedure. Research on this field of bone regeneration is ongoing, with evidence being mainly attained from preclinical studies. The purpose of this review is to summarize the current experimental and clinical evidence on the use of barrier membranes for restoration of bone defects in maxillofacial and orthopedic surgery. Although there are a few promising preliminary human studies, before clinical applications can be recommended, future research should aim to establish the 'ideal' barrier membrane and delineate the need for additional bone grafting materials aiming to 'mimic' or even accelerate the normal process of bone formation. Reproducible results and long-term observations with barrier membranes in animal studies, and particularly in large animal models, are required as well as well-designed clinical studies to evaluate their safety, efficacy and cost-effectiveness. PMID:22834465

  12. Infectivity of DWV Associated to Flower Pollen: Experimental Evidence of a Horizontal Transmission Route

    PubMed Central

    Luisi, Elena; Forzan, Mario; Giusti, Matteo; Sagona, Simona; Tolari, Francesco; Felicioli, Antonio

    2014-01-01

    Deformed wing virus (DWV) is a honeybee pathogen whose presence is generally associated with infestation of the colony by the mite Varroa destructor, leading to the onset of infections responsible for the collapse of the bee colony. DWV contaminates bee products such as royal jelly, bee-bread and honey stored within the infected hive. Outside the hive, DWV has been found in pollen loads collected directly from infected as well as uninfected forager bees. It has been shown that the introduction of virus-contaminated pollen into a DWV-free hive results in the production of virus-contaminated food, whose role in the development of infected bees from virus-free eggs has been experimentally demonstrated. The aim of this study was twofold: (i) to ascertain the presence of DWV on pollen collected directly from flowers visited by honeybees and then quantify the viral load and (ii) determine whether the virus associated with pollen is infective. The results of our investigation provide evidence that DWV is present on pollen sampled directly from visited flowers and that, following injection in individuals belonging to the pollinator species Apis mellifera, it is able to establish an active infection, as indicated by the presence of replicating virus in the head of the injected bees. We also provide the first indication that the pollinator species Osmia cornuta is susceptible to DWV infection. PMID:25419704

  13. The price elasticity of demand for heroin: Matched longitudinal and experimental evidence.

    PubMed

    Olmstead, Todd A; Alessi, Sheila M; Kline, Brendan; Pacula, Rosalie Liccardo; Petry, Nancy M

    2015-05-01

    This paper reports estimates of the price elasticity of demand for heroin based on a newly constructed dataset. The dataset has two matched components concerning the same sample of regular heroin users: longitudinal information about real-world heroin demand (actual price and actual quantity at daily intervals for each heroin user in the sample) and experimental information about laboratory heroin demand (elicited by presenting the same heroin users with scenarios in a laboratory setting). Two empirical strategies are used to estimate the price elasticity of demand for heroin. The first strategy exploits the idiosyncratic variation in the price experienced by a heroin user over time that occurs in markets for illegal drugs. The second strategy exploits the experimentally induced variation in price experienced by a heroin user across experimental scenarios. Both empirical strategies result in the estimate that the conditional price elasticity of demand for heroin is approximately -0.80. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. The price elasticity of demand for heroin: matched longitudinal and experimental evidence#

    PubMed Central

    Olmstead, Todd A.; Alessi, Sheila M.; Kline, Brendan; Pacula, Rosalie Liccardo; Petry, Nancy M.

    2015-01-01

    This paper reports estimates of the price elasticity of demand for heroin based on a newly constructed dataset. The dataset has two matched components concerning the same sample of regular heroin users: longitudinal information about real-world heroin demand (actual price and actual quantity at daily intervals for each heroin user in the sample) and experimental information about laboratory heroin demand (elicited by presenting the same heroin users with scenarios in a laboratory setting). Two empirical strategies are used to estimate the price elasticity of demand for heroin. The first strategy exploits the idiosyncratic variation in the price experienced by a heroin user over time that occurs in markets for illegal drugs. The second strategy exploits the experimentally-induced variation in price experienced by a heroin user across experimental scenarios. Both empirical strategies result in the estimate that the conditional price elasticity of demand for heroin is approximately −0.80. PMID:25702687

  15. Clinical evidence for cervical myelopathy due to Chiari malformation and spinal stenosis in a non-randomized group of patients with the diagnosis of fibromyalgia.

    PubMed

    Heffez, Dan S; Ross, Ruth E; Shade-Zeldow, Yvonne; Kostas, Konstantinos; Shah, Sagar; Gottschalk, Robert; Elias, Dean A; Shepard, Alan; Leurgans, Sue E; Moore, Charity G

    2004-10-01

    While patients with fibromyalgia report symptoms consistent with cervical myelopathy, a detailed neurological evaluation is not routine. We sought to determine if patients with fibromyalgia manifest objective neurological signs of cervical myelopathy. Two hundred and seventy patients, 18 years and older, who carried the diagnosis of fibromyalgia but who had no previously recognized neurological disease underwent detailed clinical neurological and neuroradiological evaluation for the prevalence of objective evidence of cervical myelopathy and radiological evidence of cerebellar tonsillar herniation (Chiari 1 malformation) or cervical spinal canal stenosis. Patients were primarily women (87%), of mean age 44 years, who had been symptomatic for 8 years (standard deviation, 6.3 years). The predominant complaints were neck/back pain (95%), fatigue (95%), exertional fatigue (96%), cognitive impairment (92%), instability of gait (85%), grip weakness (83%), paresthesiae (80%), dizziness (71%) and numbness (69%). Eighty-eight percent of patients reported worsening symptoms with neck extension. The neurological examination was consistent with cervical myelopathy: upper thoracic spinothalamic sensory level (83%), hyperreflexia (64%), inversion of the radial periosteal reflex (57%), positive Romberg sign (28%), ankle clonus (25%), positive Hoffman sign (26%), impaired tandem walk (23%), dysmetria (15%) and dysdiadochokinesia (13%). MRI and contrast-enhanced CT imaging of the cervical spine revealed stenosis. The mean antero-posterior (AP) spinal canal diameter at C2/3, C3/4, C4/5, C5/6, C6/7 and C7/T1 was 13.5 mm, 11.8 mm, 11.5 mm, 10.4 mm, 11.3 mm and 14.5 mm respectively, (CT images). In 46% of patients, the AP spinal diameter at C5/6 measured 10 mm, or less, with the neck positioned in mild extension, i.e., clinically significant spinal canal stenosis. MRI of the brain revealed tonsillar ectopia >5 mm in 20% of patients (mean=7.1+/-1.8 mm), i.e., Chiari 1 malformation

  16. Integrative review of implementation strategies for translation of research-based evidence by nurses.

    PubMed

    Wuchner, Staci S

    2014-01-01

    The purpose of this review was to synthesize and critique experimental and/or quasi-experimental research that has evaluated implementation strategies for translation of research-based evidence into nursing practice. Successfully implementing evidence-based research can improve patient outcomes. Identifying successful implementation strategies is imperative to move research-based evidence into practice. As implementation science gains popularity, it is imperative to understand the strategies that most effectively translate research-based evidence into practice. The review used the CINAHL and MEDLINE (Ovid) databases. Articles were included if they were experimental and/or quasi-experimental research designs, were written in English, and measured nursing compliance to translation of research-based evidence. An independent review was performed to select and critique the included articles. A wide array of interventions were completed, including visual cues, audit and feedback, educational meetings and materials, reminders, outreach, and leadership involvement. Because of the complex multimodal nature of the interventions and the variety of research topics, comparison across interventions was difficult. Many difficulties exist in determining what implementation strategies are most effective for translation of research-based evidence into practice by nurses. With these limited findings, further research is warranted to determine which implementation strategies most successfully translate research-based evidence into practice.

  17. Detrimental effects of introducing partial compulsory vaccination: experimental evidence.

    PubMed

    Betsch, Cornelia; Böhm, Robert

    2016-06-01

    During outbreaks of vaccine-preventable diseases, compulsory vaccination is sometimes discussed as a last resort to counter vaccine refusal. Besides ethical arguments, however, empirical evidence on the consequences of making selected vaccinations compulsory is lacking. Such evidence is needed to make informed public health decisions. This study therefore assesses the effect of partial compulsory vaccination on the uptake of other voluntary vaccines. A total of 297 (N) participants took part in an online experiment that simulated two sequential vaccination decisions using an incentivized behavioural vaccination game. The game framework bases on epidemiological, psychological and game-theoretical models of vaccination. Participants were randomized to the compulsory vaccination intervention (n = 144) or voluntary vaccination control group (n = 153), which determined the decision architecture of the first of two decisions. The critical second decision was voluntary for all participants. We also assessed the level of anger, vaccination attitude and perceived severity of the two diseases. Compulsory vaccination increased the level of anger among individuals with a rather negative vaccination attitude, whereas voluntary vaccination did not. This led to a decrease in vaccination uptake by 39% in the second voluntary vaccination (reactance). Making only selected vaccinations compulsory can have detrimental effects on the vaccination programme by decreasing the uptake of voluntary vaccinations. As this effect occurred especially for vaccine hesitant participants, the prevalence of vaccine hesitancy within a society will influence the damage of partial compulsory vaccination. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

  18. The impact of feedback valence and communication style on intrinsic motivation in middle childhood: Experimental evidence and generalization across individual differences.

    PubMed

    Mabbe, Elien; Soenens, Bart; De Muynck, Gert-Jan; Vansteenkiste, Maarten

    2018-06-01

    Prior research among adolescents and emerging adults has provided evidence for the beneficial effects of positive (relative to negative) feedback and an autonomy-supportive (relative to a controlling) communication style on students' intrinsic motivation. Unfortunately, similar experimental research in middle childhood is lacking. Moreover, little attention has been paid to the question of whether individual differences in personality and perceived parenting play a role in these effects. In the current experimental study (N = 110; M age  = 10.71 years), children completed puzzles at school under one of four experimental conditions, thereby crossing normative feedback valence (i.e., positive vs. negative) with communication style (i.e., autonomy supportive vs. controlling). Prior to the experiment, children filled out questionnaires tapping into the Big Five personality traits and into perceived maternal autonomy support and psychological control. After the experimental induction, children rated several motivational constructs (i.e., intrinsic motivation and need-based experiences). In addition, their voluntary behavioral persistence in a subsequent challenging puzzle task was recorded objectively. Providing positive normative feedback in an autonomy-supportive way yielded the most favorable motivational outcomes. Both feedback valence and communication style yielded an independent impact on children's experiences of competence and autonomy during task engagement, which in turn helped to explain children's elevated intrinsic motivation, as reflected by their perceived interest and behavioral persistence. A few effects were moderated by children's perceived parenting and personality traits, but the number of interactions was limited. The discussion focuses on the motivating role of positive normative feedback and an autonomy-supportive communication style for children. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Improving evidence based practice in postgraduate nursing programs: A systematic review: Bridging the evidence practice gap (BRIDGE project).

    PubMed

    Hickman, Louise D; DiGiacomo, Michelle; Phillips, Jane; Rao, Angela; Newton, Phillip J; Jackson, Debra; Ferguson, Caleb

    2018-04-01

    The nursing profession has a significant evidence to practice gap in an increasingly complex and dynamic health care environment. To evaluate effectiveness of teaching and learning strategies related to a capstone project within a Masters of Nursing program that encourage the development of evidence based practice capabilities. Systematic review that conforms to the PRISMA statement. Master's Nursing programs that include elements of a capstone project within a university setting. MEDLINE, CINAHL, Cochrane Database of Systematic Reviews, ERIC and PsycInfo were used to search for RCT's or quasi experimental studies conducted between 1979 and 9 June 2017, published in a peer reviewed journal in English. Of 1592 studies, no RCT's specifically addressed the development of evidence based practice capabilities within the university teaching environment. Five quasi-experimental studies integrated blended learning, guided design processes, small group work, role play and structured debate into Masters of Nursing research courses. All five studies demonstrated some improvements in evidence based practice skills and/or research knowledge translation, with three out of five studies demonstrating significant improvements. There is a paucity of empirical evidence supporting the best strategies to use in developing evidence based practice skills and/or research knowledge translation skills for Master's Nursing students. As a profession, nursing requires methodologically robust studies that are discipline specific to identify the best approaches for developing evidence-based practice skills and/or research knowledge translation skills within the university teaching environment. Provision of these strategies will enable the nursing profession to integrate the best empirical evidence into nursing practice. Copyright © 2018. Published by Elsevier Ltd.

  20. Experimental and clinical evidence of antioxidant therapy in acute pancreatitis

    PubMed Central

    Esrefoglu, Mukaddes

    2012-01-01

    Oxidative stress has been shown to play an important role in the pathogenesis of acute pancreatitis (AP). Antioxidants, alone or in combination with conventional therapy, should improve oxidative-stress-induced organ damage and therefore accelerate the rate of recovery. In recent years, substantial amounts of data about the efficiency of antioxidants against oxidative damage have been obtained from experiments with rodents. Some of these antioxidants have been found beneficial in the treatment of AP in humans; however, at present there is insufficient clinical data to support the benefits of antioxidants, alone or in combination with conventional therapy, in the management of AP in humans. Conflicting results obtained from experimental animals and humans may represent distinct pathophysiological mechanisms mediating tissue injury in different species. Further detailed studies should be done to clarify the exact mechanisms of tissue injury in human AP. Herein I tried to review the existing experimental and clinical studies on AP in order to determine the efficiency of antioxidants. The use of antioxidant enriched nutrition is a potential direction of clinical research in AP given the lack of clues about the efficiency and safety of antioxidant usage in patients with AP. PMID:23112545

  1. Experimental evidence of spatial memory and home range affinity in White-tailed Deer (Odocoileus virginianus)

    USGS Publications Warehouse

    Nelson, Michael E.

    2015-01-01

    The role of spatial memory in the movement of animals through landscapes remains elusive. To examine spatial memory and home range affinity of White-tailed Deer (Odocoileus virginianus) in northeastern Minnesota during 1995–2007, I translocated 17 adult does with known home ranges to unfamiliar sites and radio-tracked them after their release. Twelve does wearing transmitting radio-collars returned to their home ranges. Death and collar expiration precluded determination of whether the remaining five does would have returned to home ranges. Three of five does wearing global positioning system collars traveled throughout hundreds of square kilometres, circling, backtracking, and returning to release sites, while two others exhibited directional movement for tens of kilometres. Four does that survived to parturition stopped traveling and moved at hourly rates similar to those of control does during the first three weeks of the typical fawn-rearing period, but continued traveling later. Their aberrant extensive travel before and after interruption by parturition suggests that they recognized they were in unfamiliar areas, demonstrating both their capacity and propensity to search for and occupy the familiar space of their individual home ranges. Their successful return to home ranges provided experimental evidence of spatial memory and further elucidated its pervasive role in White-tailed Deer spatial ecology.

  2. Experimental observation of Lorenz chaos in the Quincke rotor dynamics.

    PubMed

    Peters, François; Lobry, Laurent; Lemaire, Elisabeth

    2005-03-01

    In this paper, we report experimental evidence of Lorenz chaos for the Quincke rotor dynamics. We study the angular motion of an insulating cylinder immersed in slightly conducting oil and submitted to a direct current electric field. The simple equations which describe the dynamics of the rotor are shown to be equivalent to the Lorenz equations. In particular, we observe two bifurcations in our experimental system. Above a critical value of the electric field, the cylinder rotates at a constant rate. At a second bifurcation, the system becomes chaotic. The characteristic shape of the experimental first return map provides strong evidence for Lorenz-type chaos.

  3. Experimental observation of Lorenz chaos in the Quincke rotor dynamics

    NASA Astrophysics Data System (ADS)

    Peters, François; Lobry, Laurent; Lemaire, Elisabeth

    2005-03-01

    In this paper, we report experimental evidence of Lorenz chaos for the Quincke rotor dynamics. We study the angular motion of an insulating cylinder immersed in slightly conducting oil and submitted to a direct current electric field. The simple equations which describe the dynamics of the rotor are shown to be equivalent to the Lorenz equations. In particular, we observe two bifurcations in our experimental system. Above a critical value of the electric field, the cylinder rotates at a constant rate. At a second bifurcation, the system becomes chaotic. The characteristic shape of the experimental first return map provides strong evidence for Lorenz-type chaos.

  4. Experimental Evidence of Weak Excluded Volume Effects for Nanochannel Confined DNA

    NASA Astrophysics Data System (ADS)

    Gupta, Damini; Miller, Jeremy J.; Muralidhar, Abhiram; Mahshid, Sara; Reisner, Walter; Dorfman, Kevin D.

    In the classical de Gennes picture of weak polymer nanochannel confinement, the polymer contour is envisioned as divided into a series of isometric blobs. Strong excluded volume interactions are present both within a blob and between blobs. In contrast, for semiflexible polymers like DNA, excluded volume interactions are of borderline strength within a blob but appreciable between blobs, giving rise to a chain description consisting of a string of anisometric blobs. We present experimental validation of this subtle effect of excluded volume for DNA nanochannel confinement by performing measurements of variance in chain extension of T4 DNA molecules as a function of effective nanochannel size (305-453 nm). Additionally, we show an approach to systematically reduce the effect of molecular weight dispersity of DNA samples, a typical experimental artifact, by combining confinement spectroscopy with simulations.

  5. Mechanisms of methylmercury-induced neurotoxicity: evidence from experimental studies

    PubMed Central

    Farina, Marcelo; Rocha, João B. T.; Aschner, Michael

    2011-01-01

    Neurological disorders are common, costly, and can cause enduring disability. Although mostly unknown, a few environmental toxicants are recognized causes of neurological disorders and subclinical brain dysfunction. One of the best known neurotoxins is methylmercury (MeHg), a ubiquitous environmental toxicant that leads to long-lasting neurological and developmental deficits in animals and humans. In the aquatic environment, MeHg is accumulated in fish, which represent a major source of human exposure. Although several episodes of MeHg poisoning have contributed to the understanding of the clinical symptoms and histological changes elicited by this neurotoxicant in humans, experimental studies have been pivotal in elucidating the molecular mechanisms that mediate MeHg-induced neurotoxicity. The objective of this mini-review is to summarize data from experimental studies on molecular mechanisms of MeHg-induced neurotoxicity. While the full picture has yet to be unmasked, in vitro approaches based on cultured cells, isolated mitochondria and tissue slices, as well as in vivo studies based mainly on the use of rodents, point to impairment in intracellular calcium homeostasis, alteration of glutamate homeostasis and oxidative stress as important events in MeHg-induced neurotoxicity. The potential relationship among these events is discussed, with particular emphasis on the neurotoxic cycle triggered by MeHg-induced excitotoxicity and oxidative stress. The particular sensitivity of the developing brain to MeHg toxicity, the critical role of selenoproteins and the potential protective role of selenocompounds are also discussed. These concepts provide the biochemical bases to the understanding of MeHg neurotoxicity, contributing to the discovery of endogenous and exogenous molecules that counteract such toxicity and provide efficacious means for ablating this vicious cycle. PMID:21683713

  6. Honest sexual signaling in turtles: experimental evidence of a trade-off between immune response and coloration in red-eared sliders Trachemys scripta elegans.

    PubMed

    Ibáñez, Alejandro; Polo-Cavia, Nuria; López, Pilar; Martín, José

    2014-10-01

    Sexual signals can be evolutionarily stable if they are honest and condition dependent or costly to the signaler. One possible cost is the existence of a trade-off between maintaining the immune system and the elaboration of ornaments. This hypothesis has been experimentally tested in some groups of animals but not in others such as turtles. We experimentally challenged the immune system of female red-eared sliders Trachemys scripta elegans, with a bacterial antigen (lipopolysaccharide (LPS)) without pathogenic effects to explore whether the immune activation affected visual colorful ornaments of the head. The LPS injection altered the reflectance patterns of color ornaments. In comparison to the control animals, the yellow chin stripes of injected animals exhibited (1) reduced brightness, (2) lower long wavelength (>470 nm) reflectance, and (3) lower values for carotenoid chroma. The postorbital patches of injected individuals also showed reduced very long wavelength (>570 nm) reflectance but did not change in carotenoid chroma. Thus, experimental turtles showed darker and less "yellowish" chin stripes and less "reddish" postorbital patches at the end of the experiment, whereas control turtles did not change their coloration. This is the first experimental evidence supporting the existence of a trade-off between the immune system and the expression of visual ornaments in turtles. We suggest that this trade-off may allow turtles to honestly signal individual quality via characteristics of coloration, which may have an important role in intersexual selection processes.

  7. Honest sexual signaling in turtles: experimental evidence of a trade-off between immune response and coloration in red-eared sliders Trachemys scripta elegans

    NASA Astrophysics Data System (ADS)

    Ibáñez, Alejandro; Polo-Cavia, Nuria; López, Pilar; Martín, José

    2014-10-01

    Sexual signals can be evolutionarily stable if they are honest and condition dependent or costly to the signaler. One possible cost is the existence of a trade-off between maintaining the immune system and the elaboration of ornaments. This hypothesis has been experimentally tested in some groups of animals but not in others such as turtles. We experimentally challenged the immune system of female red-eared sliders Trachemys scripta elegans, with a bacterial antigen (lipopolysaccharide (LPS)) without pathogenic effects to explore whether the immune activation affected visual colorful ornaments of the head. The LPS injection altered the reflectance patterns of color ornaments. In comparison to the control animals, the yellow chin stripes of injected animals exhibited (1) reduced brightness, (2) lower long wavelength (>470 nm) reflectance, and (3) lower values for carotenoid chroma. The postorbital patches of injected individuals also showed reduced very long wavelength (>570 nm) reflectance but did not change in carotenoid chroma. Thus, experimental turtles showed darker and less "yellowish" chin stripes and less "reddish" postorbital patches at the end of the experiment, whereas control turtles did not change their coloration. This is the first experimental evidence supporting the existence of a trade-off between the immune system and the expression of visual ornaments in turtles. We suggest that this trade-off may allow turtles to honestly signal individual quality via characteristics of coloration, which may have an important role in intersexual selection processes.

  8. Constructing a New Theory from Old Ideas and New Evidence

    ERIC Educational Resources Information Center

    Rhodes, Marjorie; Wellman, Henry

    2013-01-01

    A central tenet of constructivist models of conceptual development is that children's initial conceptual level constrains how they make sense of new evidence and thus whether exposure to evidence will prompt conceptual change. Yet little experimental evidence directly examines this claim for the case of sustained, fundamental conceptual…

  9. Synovial fluid cytology in experimental acute canine monocytic ehrlichiosis (Ehrlichia canis).

    PubMed

    Theodorou, Konstantina; Leontides, Leonidas; Siarkou, Victoria I; Petanides, Theodoros; Tsafas, Konstantinos; Harrus, Shimon; Mylonakis, Mathios E

    2015-05-15

    Evidence-based information of a cause-and-effect relationship between Ehrlichia canis infection and polyarthritis in naturally- or experimentally-infected dogs is currently lacking. The aim of this prospective study was to investigate whether synovial fluid cytological evidence of arthritis could be documented in dogs with acute monocytic ehrlichiosis. Direct synovial fluid cytology smears from eight Beagle dogs experimentally infected with E. canis were examined prior to, and on 21, 35 and 63 days post-inoculation. The cytological variables assessed included cellularity, percentages of mononuclear cells and neutrophils, macrophage reactivity and evidence of E. canis morulae. The median cellularity and percentages of mononuclear cells and neutrophils prior to inoculation did not differ when compared to post-inoculation cytological evaluation. Increased cellularity, E. canis morulae or cytological evidence of arthritis or macrophage reactivity were not observed throughout the course of the study. In the present study, no cytological evidence of arthritis was found in dogs with experimental acute canine monocytic ehrlichiosis, suggesting that E. canis infection should be considered a rather uncommon cause of arthritis in dogs. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Spontaneous Time Symmetry Breaking in System with Mixed Strategy Nash Equilibrium: Evidences in Experimental Economics Data

    NASA Astrophysics Data System (ADS)

    Wang, Zhijian; Xu, Bin; Zhejiang Collaboration

    2011-03-01

    In social science, laboratory experiment with human subjects' interaction is a standard test-bed for studying social processes in micro level. Usually, as in physics, the processes near equilibrium are suggested as stochastic processes with time-reversal symmetry (TRS). To the best of our knowledge, near equilibrium, the breaking time symmetry, as well as the existence of robust time anti-symmetry processes, has not been reported clearly in experimental economics till now. By employing Markov transition method to analysis the data from human subject 2x2 Games with wide parameters and mixed Nash equilibrium, we study the time symmetry of the social interaction process near Nash equilibrium. We find that, the time symmetry is broken, and there exists a robust time anti-symmetry processes. We also report the weight of the time anti-symmetry processes in the total processes of each the games. Evidences in laboratory marketing experiments, at the same time, are provided as one-dimension cases. In these cases, time anti-symmetry cycles can also be captured. The proposition of time anti-symmetry processes is small, but the cycles are distinguishable.

  11. Experimental evidence for adaptive personalities in a wild passerine bird

    PubMed Central

    Nicolaus, Marion; Tinbergen, Joost M.; Bouwman, Karen M.; Michler, Stephanie P. M.; Ubels, Richard; Both, Christiaan; Kempenaers, Bart; Dingemanse, Niels J.

    2012-01-01

    Individuals of the same species differ consistently in risky actions. Such ‘animal personality’ variation is intriguing because behavioural flexibility is often assumed to be the norm. Recent theory predicts that between-individual differences in propensity to take risks should evolve if individuals differ in future fitness expectations: individuals with high long-term fitness expectations (i.e. that have much to lose) should behave consistently more cautious than individuals with lower expectations. Consequently, any manipulation of future fitness expectations should result in within-individual changes in risky behaviour in the direction predicted by this adaptive theory. We tested this prediction and confirmed experimentally that individuals indeed adjust their ‘exploration behaviour’, a proxy for risk-taking behaviour, to their future fitness expectations. We show for wild great tits (Parus major) that individuals with experimentally decreased survival probability become faster explorers (i.e. increase risk-taking behaviour) compared to individuals with increased survival probability. We also show, using quantitative genetics approaches, that non-genetic effects (i.e. permanent environment effects) underpin adaptive personality variation in this species. This study thereby confirms a key prediction of adaptive personality theory based on life-history trade-offs, and implies that selection may indeed favour the evolution of personalities in situations where individuals differ in future fitness expectations. PMID:23097506

  12. Evidence-based health promotion: applying it in practice.

    PubMed

    Wong, M L

    2002-09-01

    In health promotion, we should use interventions established by evidence to be effective in improving the health of the community. This paper reviews the concepts, evaluation and use of evidence in health promotion. A literature search of evidence-based health promotion and evaluation of health promotion was conducted using Medline, Social Science Citation Index (SSCI), PsycLIT and evidence-based web sites on health promotion, health education and community preventive services. Recent issues of key journals on health promotion, health education and public health were also hand-searched. The concept of evidence in health promotion interventions is complex due to its multidimensional nature. Evidence of effectiveness in health promotion is assessed by combining quantitative data on effect change in outcome measures and qualitative data on process evaluation of health promotion activities. Limitations to the use of randomised trials in community-based health promotion interventions include ethical and logistic problems in maintaining randomisation of subjects over long periods, absence of experimental conditions in the real-world setting, contamination of control subjects and the multidimensional nature of health promotion interventions. Randomised controlled trials should be used to evaluate the effectiveness of most health education and behavioural interventions in clinical settings. When such trials are not feasible as in community-based health promotion interventions, quasi-experimental designs provide strong evidence. Multiple methods are needed to assess evidence of effectiveness of health promotion programmes. Appropriate practice of evidence-based health promotion requires consideration of quality of available evidence, local values and prevailing resources.

  13. Monitoring healthy and disturbed sleep through smartphone applications: a review of experimental evidence.

    PubMed

    Fino, Edita; Mazzetti, Michela

    2018-04-23

    Smartphone applications are considered as the prime candidate for the purposes of large-scale, low-cost and long-term sleep monitoring. How reliable and scientifically grounded is smartphone-based assessment of healthy and disturbed sleep remains a key issue in this direction. Here we offer a review of validation studies of sleep applications to the aim of providing some guidance in terms of their reliability to assess sleep in healthy and clinical populations, and stimulating further examination of their potential for clinical use and improved sleep hygiene. Electronic literature review was conducted on Pubmed. Eleven validation studies published since 2012 were identified, evaluating smartphone applications' performance compared to standard methods of sleep assessment in healthy and clinical samples. Studies with healthy populations show that most sleep applications meet or exceed accuracy levels of wrist-based actigraphy in sleep-wake cycle discrimination, whereas performance levels drop in individuals with low sleep efficiency (SE) and in clinical populations, mirroring actigraphy results. Poor correlation with polysomnography (PSG) sleep sub-stages is reported by most accelerometer-based apps. However, multiple parameter-based applications (i.e., EarlySense, SleepAp) showed good capability in detection of sleep-wake stages and sleep-related breathing disorders (SRBD) like obstructive sleep apnea (OSA) respectively with values similar to PSG. While the reviewed evidence suggests a potential role of smartphone sleep applications in pre-screening of SRBD, more experimental studies are warranted to assess their reliability in sleep-wake detection particularly. Apps' utility in post treatment follow-up at home or as an adjunct to the sleep diary in clinical setting is also stressed.

  14. Experimental Evidence of the Tonic Vibration Reflex during Whole-Body Vibration of the Loaded and Unloaded Leg

    PubMed Central

    Zaidell, Lisa N.; Mileva, Katya N.; Sumners, David P.; Bowtell, Joanna L.

    2013-01-01

    Increased muscle activation during whole-body vibration (WBV) is mainly ascribed to a complex spinal and supraspinal neurophysiological mechanism termed the tonic vibration reflex (TVR). However, TVR has not been experimentally demonstrated during low-frequency WBV, therefore this investigation aimed to determine the expression of TVR during WBV.  Whilst seated, eight healthy males were exposed to either vertical WBV applied to the leg via the plantar-surface of the foot, or Achilles tendon vibration (ATV) at 25Hz and 50Hzfor 70s. Ankle plantar-flexion force, tri-axial accelerations at the shank and vibration source, and surface EMG activity of m. soleus (SOL) and m. tibialis anterior (TA) were recorded from the unloaded and passively loaded leg to simulate body mass supported during standing.  Plantar flexion force was similarly augmented by WBV and ATV and increased over time in a load- and frequency dependent fashion. SOL and TA EMG amplitudes increased over time in all conditions independently of vibration mode. 50Hz WBV and ATV resulted in greater muscle activation than 25Hz in SOL when the shank was loaded and in TA when the shank was unloaded despite the greater transmission of vertical acceleration from source to shank with 25Hz and WBV, especially during loading. Low-amplitude WBV of the unloaded and passively loaded leg produced slow tonic muscle contraction and plantar-flexion force increase of similar magnitudes to those induced by Achilles tendon vibration at the same frequencies. This study provides the first experimental evidence supporting the TVR as a plausible mechanism underlying the neuromuscular response to whole-body vibration. PMID:24386466

  15. Induction and inhibition of diapause by the same photoperiod: experimental evidence for a "double circadian oscillator clock".

    PubMed

    Spieth, Hubert R; Xue, Fangsen; Strau, Katharina

    2004-12-01

    On the southern Iberian Peninsula, the seasonal life history of the large white butterfly, Pieris brassicae, comprises 2 different photoperiodically induced developmental arrests: a hibernation diapause at photophases < 11 h and an estivation diapause at photophases > 14 h. At intermediate photophases (12 h to 13 h), the butterfly responds with a nondiapause. Combined with the experimental setup to determine photosensitivity in insects, the different photoperiodic responses at long-, intermediate-, and short-night conditions were examined to gain more insight into the time measurement mechanism in P. brassicae. The study reveals evidence for a "double circadian oscillator clock" mechanism that is based on 2 submechanisms, a "short-night determining system" and a separate "long-night determining system." This conclusion was drawn from the facts that an LD 9:15 long-night induces a hibernation diapause but inhibits an estivation diapause and, conversely, that an LD 16:8 short-night inhibits a hibernation diapause but induces an estivation diapause. This opposite effect of the same photoperiod supports the argument for the existence of 2 independent targets for light-dark cycles, interpreted as 2 antagonistic time measurement systems. The existence and independence of 2 systems was further shown by differences in long-night versus short-night responses regarding photosensitivity, temperature dependence, and heritable factors. The long-night measurement system is most effective in the 5th larval stage, is highly affected by temperature, and is easy to manipulate by selective inbreeding. The short-night measurement system is most effective in the 4th larval stage, is largely temperature compensated, and is not affected by experimental manipulation of the longnight measurement system.

  16. Experimental evidence and modelling of drought induced alternative stable soil moisture states

    NASA Astrophysics Data System (ADS)

    Robinson, David; Jones, Scott; Lebron, Inma; Reinsch, Sabine; Dominguez, Maria; Smith, Andrew; Marshal, Miles; Emmett, Bridget

    2017-04-01

    The theory of alternative stable states in ecosystems is well established in ecology; however, evidence from manipulation experiments supporting the theory is limited. Developing the evidence base is important because it has profound implications for ecosystem management. Here we show evidence of the existence of alternative stable soil moisture states induced by drought in an upland wet heath. We used a long-term (15 yrs) climate change manipulation experiment with moderate sustained drought, which reduced the ability of the soil to retain soil moisture by degrading the soil structure, reducing moisture retention. Moreover, natural intense droughts superimposed themselves on the experiment, causing an unexpected additional alternative soil moisture state to develop, both for the drought manipulation and control plots; this impaired the soil from rewetting in winter. Our results show the coexistence of three stable states. Using modelling with the Hydrus 1D software package we are able to show the circumstances under which shifts in soil moisture states are likely to occur. Given the new understanding it presents a challenge of how to incorporate feedbacks, particularly related to soil structure, into soil flow and transport models?

  17. Income Mobility Breeds Tolerance for Income Inequality: Cross-National and Experimental Evidence.

    PubMed

    Shariff, Azim F; Wiwad, Dylan; Aknin, Lara B

    2016-05-01

    American politicians often justify income inequality by referencing the opportunities people have to move between economic stations. Though past research has shown associations between income mobility and resistance to wealth redistribution policies, no experimental work has tested whether perceptions of mobility influence tolerance for inequality. In this article, we present a cross-national comparison showing that income mobility is associated with tolerance for inequality and experimental work demonstrating that perceptions of higher mobility directly affect attitudes toward inequality. We find support for both the prospect of upward mobility and the view that peoples' economic station is the product of their own efforts, as mediating mechanisms. © The Author(s) 2016.

  18. Multiple Openings and Competitiveness of Forward Markets: Experimental Evidence

    PubMed Central

    Ferreira, José Luis; Kujal, Praveen; Rassenti, Stephen

    2016-01-01

    We test the competition enhancing effect of selling forward in experimental Cournot duopoly and quadropoly with multiple forward markets. We find that two forward periods yields competitive outcomes and that the results are very close to the predicted theoretical results for quantity setting duopolies and quadropolies. Our experiments lend strong support to the hypothesis that forward markets are competition enhancing. We then test a new market that allows for endogenously determined indefinitely many forward periods that only close when sellers coordinate on selling a zero amount in a forward market. We find that the outcomes under an endogenous close rule are also very competitive. These results hold for both duopolies and quadropolies. PMID:27442516

  19. Experimental evidence of a symbiosis between red-cockaded woodpeckers and fungi

    Treesearch

    Michelle A. Jusino; Daniel L. Lindner; Mark T. Banik; Kevin R. Rose; Jeffrey R. Walters

    2016-01-01

    Primary cavity excavators, such as woodpeckers, are ecosystem engineers in many systems. Associations between cavity excavators and fungi have long been hypothesized to facilitate cavity excavation, but these relationships have not been experimentally verified. Fungi may help excavators by softening wood, while excavators may facilitate fungal dispersal. Here we...

  20. Experimental evidence for improved neuroimaging interpretation using three-dimensional graphic models.

    PubMed

    Ruisoto, Pablo; Juanes, Juan Antonio; Contador, Israel; Mayoral, Paula; Prats-Galino, Alberto

    2012-01-01

    Three-dimensional (3D) or volumetric visualization is a useful resource for learning about the anatomy of the human brain. However, the effectiveness of 3D spatial visualization has not yet been assessed systematically. This report analyzes whether 3D volumetric visualization helps learners to identify and locate subcortical structures more precisely than classical cross-sectional images based on a two dimensional (2D) approach. Eighty participants were assigned to each experimental condition: 2D cross-sectional visualization vs. 3D volumetric visualization. Both groups were matched for age, gender, visual-spatial ability, and previous knowledge of neuroanatomy. Accuracy in identifying brain structures, execution time, and level of confidence in the response were taken as outcome measures. Moreover, interactive effects between the experimental conditions (2D vs. 3D) and factors such as level of competence (novice vs. expert), image modality (morphological and functional), and difficulty of the structures were analyzed. The percentage of correct answers (hit rate) and level of confidence in responses were significantly higher in the 3D visualization condition than in the 2D. In addition, the response time was significantly lower for the 3D visualization condition in comparison with the 2D. The interaction between the experimental condition (2D vs. 3D) and difficulty was significant, and the 3D condition facilitated the location of difficult images more than the 2D condition. 3D volumetric visualization helps to identify brain structures such as the hippocampus and amygdala, more accurately and rapidly than conventional 2D visualization. This paper discusses the implications of these results with regards to the learning process involved in neuroimaging interpretation. Copyright © 2012 American Association of Anatomists.

  1. Modulation of Antioxidant Enzymatic Activities by Certain Antiepileptic Drugs (Valproic Acid, Oxcarbazepine, and Topiramate): Evidence in Humans and Experimental Models

    PubMed Central

    Cárdenas-Rodríguez, Noemí; Coballase-Urrutia, Elvia; Rivera-Espinosa, Liliana; Romero-Toledo, Arantxa; Sampieri, Aristides III; Ortega-Cuellar, Daniel; Montesinos-Correa, Hortencia; Floriano-Sánchez, Esaú; Carmona-Aparicio, Liliana

    2013-01-01

    It is estimated that at least 100 million people worldwide will suffer from epilepsy at some point in their lives. This neurological disorder induces brain death due to the excessive liberation of glutamate, which activates the postsynaptic N-methyl-D-aspartic acid (NMDA) receptors, which in turn cause the reuptake of intracellular calcium (excitotoxicity). This excitotoxicity elicits a series of events leading to nitric oxide synthase (NOS) activation and the generation of reactive oxygen species (ROS). Several studies in experimental models and in humans have demonstrated that certain antiepileptic drugs (AEDs) exhibit antioxidant effects by modulating the activity of various enzymes associated with this type of stress. Considering the above-mentioned data, we aimed to compile evidence elucidating how AEDs such as valproic acid (VPA), oxcarbazepine (OXC), and topiramate (TPM) modulate oxidative stress. PMID:24454986

  2. Quasi experimental designs in pharmacist intervention research.

    PubMed

    Krass, Ines

    2016-06-01

    Background In the field of pharmacist intervention research it is often difficult to conform to the rigorous requirements of the "true experimental" models, especially the requirement of randomization. When randomization is not feasible, a practice based researcher can choose from a range of "quasi-experimental designs" i.e., non-randomised and at time non controlled. Objective The aim of this article was to provide an overview of quasi-experimental designs, discuss their strengths and weaknesses and to investigate their application in pharmacist intervention research over the previous decade. Results In the literature quasi experimental studies may be classified into five broad categories: quasi-experimental design without control groups; quasi-experimental design that use control groups with no pre-test; quasi-experimental design that use control groups and pre-tests; interrupted time series and stepped wedge designs. Quasi-experimental study design has consistently featured in the evolution of pharmacist intervention research. The most commonly applied of all quasi experimental designs in the practice based research literature are the one group pre-post-test design and the non-equivalent control group design i.e., (untreated control group with dependent pre-tests and post-tests) and have been used to test the impact of pharmacist interventions in general medications management as well as in specific disease states. Conclusion Quasi experimental studies have a role to play as proof of concept, in the pilot phases of interventions when testing different intervention components, especially in complex interventions. They serve to develop an understanding of possible intervention effects: while in isolation they yield weak evidence of clinical efficacy, taken collectively, they help build a body of evidence in support of the value of pharmacist interventions across different practice settings and countries. However, when a traditional RCT is not feasible for

  3. Assessing the Role of Experimental Evidence for Interface Judgment: Licensing of Negative Polarity Items, Scalar Readings, and Focus

    PubMed Central

    Giannakidou, Anastasia; Etxeberria, Urtzi

    2018-01-01

    This paper reviews a series of experimental studies that address what we call “interface judgment,” which is the complex judgment involving integration from multiple levels of grammatical representation such as the syntax-semantics and prosody-semantics interface. We first discuss the results from the ERP literature connected to NPI licensing in different languages, paying particular attention to the N400 and the P600 as neural correlates of this specific phenomenon and focusing on the study by Xiang et al. (2016). The results of this study show evidence that there are two distinct NPI licensing mechanisms, i.e., licensing and rescuing, in line with Giannakidou (1998, 2006). Then we discuss an acceptability judgment task on Greek NPIs which supports the negativity as a scale hypothesis (Zwarts, 1995, 1996; Giannakidou, 1998). For the semantics-prosody interface judgment, we discuss two types of findings on two different phenomena and languages: (i) the study by Giannakidou and Yoon (2016) on scalar and non-scalar NPIs in Greek and Korean, which serves as the foundation for Chatzikonstantinou's (2016) study of production data showing distinct prosodic properties in emphatic (scalar) and non-emphatic (non-scalar) Greek NPIs; (ii) a (production and perception) study by Etxeberria and Irurtzun (2015) on the prosodic disambiguation of the scalar/non-scalar readings of sentences containing the focus particle “ere” in Basque. The main conclusion of the paper is that experimental methods of the kind discussed in the paper are useful in establishing physical, quantitative correlates of interface judgment. PMID:29515470

  4. Reproductive interference and fecundity affect competitive interactions of sibling species with low mating barriers: experimental and theoretical evidence.

    PubMed

    Gebiola, M; Kelly, S E; Velten, L; Zug, R; Hammerstein, P; Giorgini, M; Hunter, M S

    2017-12-01

    When allopatric species with incomplete prezygotic isolation come into secondary contact, the outcome of their interaction is not easily predicted. The parasitoid wasp Encarsia suzannae (iES), infected by Cardinium inducing cytoplasmic incompatibility (CI), and its sibling species E. gennaroi (EG), not infected by bacterial endosymbionts, may have diverged because of the complementary action of CI and asymmetric hybrid incompatibilities. Whereas postzygotic isolation is now complete because of sterility of F1 hybrid progeny, prezygotic isolation is still incipient. We set up laboratory population cage experiments to evaluate the outcome of the interaction between ES and EG in two pairwise combinations: iES vs EG and cured ES (cES, where Cardinium was removed with antibiotics) vs EG. We also built a theoretical model aimed at exploring the role of life-history differences and asymmetric mating on competitive outcomes. In three of four cages in each treatment, ES dominated the interaction. We found evidence for reproductive interference, driven by asymmetric mating preferences, that gave a competitive edge to ES, the species that better discriminated against heterospecifics. However, we did not find the fecundity cost previously shown to be associated with Cardinium infection in iES. The model largely supported the experimental results. The finding of only a slight competitive edge of ES over EG in population cages suggests that in a more heterogeneous environment the species could coexist. This is supported by evidence that the two species coexist in sympatry, where preliminary data suggest reproductive character displacement may have reinforced postzygotic isolation.

  5. Experimental evidence of interhemispheric transport from airborne carbon monoxide measurements

    NASA Technical Reports Server (NTRS)

    Newell, R. E.; Gauntner, D. J.

    1979-01-01

    During the period 28-30 October 1977, a Pan American 747-SP aircraft flew around the world with an automated instrument package that included measurements of atmospheric CO made every 4 sec. The flight path extended from San Francisco, over the North Pole to London, south to Capetown, over the South Pole to Auckland, and back to San Francisco. The data collected show large changes with longitude, which are interpreted as direct evidence of interhemispheric mixing. Possible sources for CO are discussed.

  6. On the early emergence of reverse transcription: theoretical basis and experimental evidence

    NASA Technical Reports Server (NTRS)

    Lazcano, A.; Valverde, V.; Hernandez, G.; Gariglio, P.; Fox, G. E.; Oro, J.

    1992-01-01

    Reverse transcriptase (RT) was first discovered as an essential catalyst in the biological cycle of retroviruses. However, in the past years evidence has accumulated showing that RTs are involved in a surprisingly large number of RNA-mediated transpositional events that include both viral and nonviral genetic entities. Although it is probable that some RT-bearing genetic elements like the different types of AIDS viruses and the mammalian LINE family have arisen in recent geological times, the possibility that reverse transcription first took place in the early Archean is supported by (1) the hypothesis that RNA preceded DNA as cellular genetic material; (2) the existence of homologous regions of the subunit tau of the E. coli DNA polymerase III with the simian immunodeficiency virus RT, the hepatitis B virus RT, and the beta' subunit of the E. coli RNA polymerase (McHenry et al. 1988); (3) the presence of several conserved motifs, including a 14-amino-acid segment that consists of an Asp-Asp pair flanked by hydrophobic amino acids, which are found in all RTs and in most cellular and viral RNA polymerases. However, whether extant RTs descend from the primitive polymerase involved in the RNA-to-DNA transition remains unproven. Substrate specificity of the AMV and HIV-1 RTs can be modified in the presence of Mn2+, a cation which allows them to add ribonucleotides to an oligo (dG) primer in a template-dependent reaction. This change in specificity is comparable to that observed under similar conditions in other nucleic acid polymerases. This experimentally induced change in RT substrate specificity may explain previous observations on the misincorporation of ribonucleotides by the Maloney murine sarcoma virus RT in the minus and plus DNA of this retrovirus (Chen and Temin 1980). Our results also suggest that HIV-infected macrophages and T-cell cells may contain mixed polynucleotides containing both ribo- and deoxyribonucleotides. The evolutionary significance of these

  7. Experimental evidence for an effect of early-diagenetic interaction between labile and refractory marine sedimentary organic matter on nitrogen dynamics

    NASA Astrophysics Data System (ADS)

    Turnewitsch, Robert; Domeyer, Bettina; Graf, Gerhard

    2007-05-01

    In most natural sedimentary systems labile and refractory organic material (OM) occur concomitantly. Little, however, is known on how different kinds of OM interact and how such interactions affect early diagenesis in sediments. In a simple sediment experiment, we investigated how interactions of OM substrates of different degradability affect benthic nitrogen (N) dynamics. Temporal evolution of a set of selected biogeochemical parameters was monitored in sandy sediment over 116 days in three experimental set-ups spiked with labile OM (tissue of Mytilus edulis), refractory OM (mostly aged Zostera marina and macroalgae), and a 1:1 mixture of labile and refractory OM. The initial amounts of particulate organic carbon (POC) were identical in the three set-ups. To check for non-linear interactions between labile and refractory OM, the evolution of the mixture system was compared with the evolution of the simple sum of the labile and refractory systems, divided by two. The sum system is the experimental control where labile and refractory OM are virtually combined but not allowed to interact. During the first 30 days there was evidence for net dissolved-inorganic-nitrogen (DIN) production followed by net DIN consumption. (Here 'DIN' is the sum of ammonium, nitrite and nitrate.) After ˜ 30 days a quasi steady state was reached. Non-linear interactions between the two types of OM were reflected by three main differences between the early-diagenetic evolutions of nitrogen dynamics of the mixture and sum (control) systems: (1) In the mixture system the phases of net DIN production and consumption commenced more rapidly and were more intense. (2) The mixture system was shifted towards a more oxidised state of DIN products [as indicated by increased (nitrite + nitrate)/(ammonium) ratios]. (3) There was some evidence that more OM, POC and particulate nitrogen were preserved in the mixture system. That is, in the mixture system more particulate OM was preserved while a higher

  8. Experimental measurement of ablation effects in plasma armature railguns

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Parker, J.V.; Parsons, W.M.

    1986-01-01

    Experimental evidence supporting the importance of ablation in plasma armature railguns is presented. Experiments conducted using the HYVAX and MIDI-2 railguns are described. Several indirect effects of ablation are identified from the experimental results. An improved ablation model of plasma armature dynamics is proposed which incorporates the restrike process.

  9. Experimental measurement of ablation effects in plasma armature railguns

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Parker, J.V.; Parsons, W.M.

    1986-11-01

    Experimental evidence supporting the importance of ablation in plasma armature railguns is presented. Experiments conducted using the HYVAX and MIDI-2 railguns are described. Several indirect effects of ablation are identified from the experimental results. An improved ablation model of plasma armature dynamics is proposed which incorporates the restrike process.

  10. Long-Term Effects of Teacher Performance Pay: Experimental Evidence from India

    ERIC Educational Resources Information Center

    Muralidharan, Karthik

    2012-01-01

    While the idea of teacher performance-pay is increasingly making its way into policy, the evidence on the effectiveness of such programs is both limited and mixed. The central questions in the literature on teacher performance pay to date have been whether teacher performance pay based on test scores can improve student achievement, and whether…

  11. Glazed clay pottery and lead exposure in Mexico: Current experimental evidence.

    PubMed

    Diaz-Ruiz, Araceli; Tristán-López, Luis Antonio; Medrano-Gómez, Karen Itzel; Torres-Domínguez, Juan Alejandro; Ríos, Camilo; Montes, Sergio

    2017-11-01

    Lead exposure remains a significant environmental problem; lead is neurotoxic, especially in developing humans. In Mexico, lead in human blood is still a concern. Historically, much of the lead exposure is attributed to the use of handcrafted clay pottery for cooking, storing and serving food. However, experimental cause-and-effect demonstration is lacking. The present study explores this issue with a prospective experimental approach. We used handcrafted clay containers to prepare and store lemonade, which was supplied as drinking water to pregnant rats throughout the gestational period. We found that clay pots, jars, and mugs leached on average 200 µg/l lead, and exposure to the lemonade resulted in 2.5 µg/dl of lead in the pregnant rats' blood. Neonates also showed increased lead content in the hippocampus and cerebellum. Caspase-3 activity was found to be statistically increased in the hippocampus in prenatally exposed neonates, suggesting increased apoptosis in that brain region. Glazed ceramics are still an important source of lead exposure in Mexico, and our results confirm that pregnancy is a vulnerable period for brain development.

  12. Experimental identification of nitrogen-vacancy complexes in nitrogen implanted silicon

    NASA Astrophysics Data System (ADS)

    Adam, Lahir Shaik; Law, Mark E.; Szpala, Stanislaw; Simpson, P. J.; Lawther, Derek; Dokumaci, Omer; Hegde, Suri

    2001-07-01

    Nitrogen implantation is commonly used in multigate oxide thickness processing for mixed signal complementary metal-oxide-semiconductor and System on a Chip technologies. Current experiments and diffusion models indicate that upon annealing, implanted nitrogen diffuses towards the surface. The mechanism proposed for nitrogen diffusion is the formation of nitrogen-vacancy complexes in silicon, as indicated by ab initio studies by J. S. Nelson, P. A. Schultz, and A. F. Wright [Appl. Phys. Lett. 73, 247 (1998)]. However, to date, there does not exist any experimental evidence of nitrogen-vacancy formation in silicon. This letter provides experimental evidence through positron annihilation spectroscopy that nitrogen-vacancy complexes indeed form in nitrogen implanted silicon, and compares the experimental results to the ab initio studies, providing qualitative support for the same.

  13. Pursuing Quality Evidence: Applying Single-Subject Quality Indicators to Non-Experimental Qualitative Educational Research

    ERIC Educational Resources Information Center

    Stodden, Robert A.; Yamamoto, Kathryn K.; Folk, Eric; Kong, Eran; Otsuji, Derek N.

    2013-01-01

    The need for quality evidence in support of strategies used while working with persons with autism and intellectual disability (ID) has been long been recognized by researchers and practitioners. The authors reviewed and applied a number of evidence-based indicators, developed through the "What Works Clearinghouse" (WWC), to the conduct…

  14. Bias against foreign-born or foreign-trained doctors: experimental evidence.

    PubMed

    Louis, Winnifred R; Lalonde, Richard N; Esses, Victoria M

    2010-12-01

    Bias against foreign-born or -trained medical students and doctors is not well understood, despite its documented impact on recruitment, integration and retention. This research experimentally examines the interaction of location of medical education and nationality in evaluations of doctors' competence and trustworthiness. A convenience sample of prospective patients evaluated fictitious candidates for a position as a doctor in community practice at a new local health clinic. All applicants were described as having the same personality profile, legal qualifications to practise, a multi-degree education and relevant work experience. The location of medical education (the candidate's home country or the UK) and national background (Australia or Pakistan) of the applicants were independently experimentally manipulated. Consistent with previous research on skills discounting and bias, foreign-born candidates were evaluated less favourably than native-born candidates, despite their comparable education level, work experience and personality. However, overseas medical education obtained in the First World both boosted evaluations (of competence and trustworthiness) and attenuated bias based on nationality. The present findings demonstrate the selective discounting of foreign-born doctors' credentials. The data show an interaction of location of medical education and birth nationality in bias against foreign doctors. On an applied level, the data document that the benefits of medical education obtained in the First World can extend beyond its direct outcomes (high-quality training and institutional recognition) to the indirect benefit of the attenuation of patient bias based on nationality. © Blackwell Publishing Ltd 2010.

  15. Characterization of Evidence for Human System Risk Assessment

    NASA Technical Reports Server (NTRS)

    Steinberg, S. L.; Van Baalen, M.; Rossi, M.; Riccio, G.; Romero, E.; Francisco, D.

    2016-01-01

    Understanding the kinds of evidence available and using the best evidence to answer a question is critical to evidenced-based decision-making, and it requires synthesis of evidence from a variety of sources. Categorization of human system risks in spaceflight, in particular, focuses on how well the integration and interpretation of all available evidence informs the risk statement that describes the relationship between spaceflight hazards and an outcome of interest. A mature understanding and categorization of these risks requires: 1) sufficient characterization of risk, 2) sufficient knowledge to determine an acceptable level of risk (i.e., a standard), 3) development of mitigations to meet the acceptable level of risk, and 4) identification of factors affecting generalizability of the evidence to different design reference missions. In the medical research community, evidence is often ranked by increasing confidence in findings gleaned from observational and experimental research (e.g., "levels of evidence"). However, an approach based solely on aspects of experimental design is problematic in assessing human system risks for spaceflight. For spaceflight, the unique challenges and opportunities include: (1) The independent variables in most evidence are the hazards of spaceflight, such as space radiation or low gravity, which cannot be entirely duplicated in terrestrial (Earth-based) analogs, (2) Evidence is drawn from multiple sources including medical and mission operations, Lifetime Surveillance of Astronaut Health (LSAH), spaceflight research (LSDA), and relevant environmental & terrestrial databases, (3) Risk metrics based primarily on LSAH data are typically derived from available prevalence or incidence data, which may limit rigorous interpretation, (4) The timeframe for obtaining adequate spaceflight sample size (n) is very long, given the small population, (5) Randomized controlled trials are unattainable in spaceflight, (6) Collection of personal and

  16. Neurovascular unit dysfunction with blood-brain barrier hyperpermeability contributes to major depressive disorder: a review of clinical and experimental evidence

    PubMed Central

    2013-01-01

    About one-third of people with major depressive disorder (MDD) fail at least two antidepressant drug trials at 1 year. Together with clinical and experimental evidence indicating that the pathophysiology of MDD is multifactorial, this observation underscores the importance of elucidating mechanisms beyond monoaminergic dysregulation that can contribute to the genesis and persistence of MDD. Oxidative stress and neuroinflammation are mechanistically linked to the presence of neurovascular dysfunction with blood-brain barrier (BBB) hyperpermeability in selected neurological disorders, such as stroke, epilepsy, multiple sclerosis, traumatic brain injury, and Alzheimer’s disease. In contrast to other major psychiatric disorders, MDD is frequently comorbid with such neurological disorders and constitutes an independent risk factor for morbidity and mortality in disorders characterized by vascular endothelial dysfunction (cardiovascular disease and diabetes mellitus). Oxidative stress and neuroinflammation are implicated in the neurobiology of MDD. More recent evidence links neurovascular dysfunction with BBB hyperpermeability to MDD without neurological comorbidity. We review this emerging literature and present a theoretical integration between these abnormalities to those involving oxidative stress and neuroinflammation in MDD. We discuss our hypothesis that alterations in endothelial nitric oxide levels and endothelial nitric oxide synthase uncoupling are central mechanistic links in this regard. Understanding the contribution of neurovascular dysfunction with BBB hyperpermeability to the pathophysiology of MDD may help to identify novel therapeutic and preventative approaches. PMID:24289502

  17. Quality Appraisal of Single-Subject Experimental Designs: An Overview and Comparison of Different Appraisal Tools

    ERIC Educational Resources Information Center

    Wendt, Oliver; Miller, Bridget

    2012-01-01

    Critical appraisal of the research literature is an essential step in informing and implementing evidence-based practice. Quality appraisal tools that assess the methodological quality of experimental studies provide a means to identify the most rigorous research suitable for evidence-based decision-making. In single-subject experimental research,…

  18. Dose-specific effects of transcutaneous electrical nerve stimulation (TENS) on experimental pain: a systematic review.

    PubMed

    Claydon, Leica S; Chesterton, Linda S; Barlas, Panos; Sim, Julius

    2011-09-01

    To determine the hypoalgesic effects of transcutaneous electrical nerve stimulation (TENS) parameter combinations on experimental models in healthy humans. Searches were performed using the electronic databases Ovid MEDLINE, CINAHL, AMED, and Web of Science (from inception to December 2009). Manual searches of journals and reference lists of retrieved trials were also performed. Randomized controlled trials (RCTs) were included in the review if they compared the hypoalgesic effect of TENS relative with placebo and control, using an experimental pain model in healthy human participants. Two reviewers independently selected the trials, assessed their methodologic quality and extracted data. Forty-three RCTs were eligible for inclusion. A best evidence synthesis revealed: Overall "conflicting" (inconsistent findings in multiple RCTs) evidence of TENS efficacy on experimental pain irrespective of TENS parameters used. Overall intense TENS has "moderate" evidence of efficacy (1 high-quality and 2 low-quality trials). Conventional TENS has overall conflicting evidence of efficacy, this is derived from "strong" evidence of efficacy (generally consistent findings in multiple high-quality RCTs) on pressure pain but strong evidence of inefficacy on other pain models. "Limited" evidence (positive findings from 1 RCT) of hypoalgesia exists for some novel parameters. Low-intensity, low-frequency, local TENS has strong evidence of inefficacy. Inappropriate TENS (using "barely perceptible" intensities) has moderate evidence of inefficacy. The level of hypoalgesic efficacy of TENS is clearly dependent on TENS parameter combination selection (defined in terms of intensity, frequency, and stimulation site) and experimental pain model. Future clinical RCTs may consider these TENS dose responses.

  19. Loss for photoemission versus gain for Auger: Direct experimental evidence of crystal-field splitting and charge transfer in photoelectron spectroscopy

    DOE PAGES

    Woicik, J. C.; Weiland, C.; Rumaiz, A. K.

    2015-05-29

    Here, we find a 5 eV satellite in the Ti1s photoelectron spectrum of the transition-metal oxide SrTiO 3. This satellite appears in addition to the well-studied 13 eV structure that is typically associated with the Ti2p core line. We give direct experimental evidence that the presence of two satellites is due to the crystal-field splitting of the metal 3d orbitals. They originate from ligand 2pt 2g → metal3dt 2g and ligand 2pe g → metal 3de g monopole charge-transfer excitations within the sudden approximation of quantum mechanics. This assignment is made by the energetics of the resonant and high-energy thresholdmore » behaviors of the TiK–L 2L 3 Auger decay that follows Ti1s photoionization.« less

  20. A Review of Evidence for High Life Coefficients on Propeller and Rotor Blades Under Static Thrust Conditions with Some New Experimental Results

    NASA Technical Reports Server (NTRS)

    Talbot, Peter D.; Meyer, Mark; Branum, Lonnie; Burks, John S. (Technical Monitor)

    1994-01-01

    Interest has increased recently in the thrust-producing capability of rotors at very high collective pitch angles. An early reference noted this behaviour in rotors and offered alternative models for section lift characteristics to explain it. The same phenomenon was coincidentally noted and used in a propeller code, resulting in very good correlation with static thrust data. The proposed paper will present experimental data demonstrating the pronounced persistence of thrust for propellers at increasing collective pitch angles. Comparisons with blade element/momentum theory will be made. These results are expected to point to the need to define (ultimately to explain) aerodynamic lift and drag behaviour in a rotating environment. Experimental measurements made by the U.S. Army Aeroflightdynamics Directorate at the Ames Research Center have shown that locally measured normal force coefficients along the span of a highly twisted rotor blade continue to increase at high values of collective pitch. In some cases these coefficients exceed expected values for the same type of airfoil tested under two dimensional conditions. To date no one to the authors' knowledge has defined the variation of C(n) with pitch for very high angles (to 45 deg) in a rotating environment and for a blade of reasonably high aspect ratio; however, total propeller thrust measurements support the idea that stalling does not occur in the same way as on a wing. This paper will present experimental data in the form of surface pressure distributions as well as flow visualization (microtufts) to explore the aerodynamic behavior of the rotating airfoil at high values of blade incidence. This paper also reviews experimental evidence and infers some high lift coefficient behavior from it. Comparisons between predicted thrust, utilizing modified airfoil characteristics and a blade element model, and measured thrust for both rotors and propellers that cover the extremes of collective pitch are shown and

  1. GEOMORPHOLOGY. Experimental evidence for hillslope control of landscape scale.

    PubMed

    Sweeney, K E; Roering, J J; Ellis, C

    2015-07-03

    Landscape evolution theory suggests that climate sets the scale of landscape dissection by modulating the competition between diffusive processes that sculpt convex hillslopes and advective processes that carve concave valleys. However, the link between the relative dominance of hillslope and valley transport processes and landscape scale is difficult to demonstrate in natural landscapes due to the episodic nature of erosion. Here, we report results from laboratory experiments combining diffusive and advective processes in an eroding landscape. We demonstrate that rainsplash-driven disturbances in our experiments are a robust proxy for hillslope transport, such that increasing hillslope transport efficiency decreases drainage density. Our experimental results demonstrate how the coupling of climate-driven hillslope- and valley-forming processes, such as bioturbation and runoff, dictates the scale of eroding landscapes. Copyright © 2015, American Association for the Advancement of Science.

  2. Experimental scattershot boson sampling

    PubMed Central

    Bentivegna, Marco; Spagnolo, Nicolò; Vitelli, Chiara; Flamini, Fulvio; Viggianiello, Niko; Latmiral, Ludovico; Mataloni, Paolo; Brod, Daniel J.; Galvão, Ernesto F.; Crespi, Andrea; Ramponi, Roberta; Osellame, Roberto; Sciarrino, Fabio

    2015-01-01

    Boson sampling is a computational task strongly believed to be hard for classical computers, but efficiently solvable by orchestrated bosonic interference in a specialized quantum computer. Current experimental schemes, however, are still insufficient for a convincing demonstration of the advantage of quantum over classical computation. A new variation of this task, scattershot boson sampling, leads to an exponential increase in speed of the quantum device, using a larger number of photon sources based on parametric down-conversion. This is achieved by having multiple heralded single photons being sent, shot by shot, into different random input ports of the interferometer. We report the first scattershot boson sampling experiments, where six different photon-pair sources are coupled to integrated photonic circuits. We use recently proposed statistical tools to analyze our experimental data, providing strong evidence that our photonic quantum simulator works as expected. This approach represents an important leap toward a convincing experimental demonstration of the quantum computational supremacy. PMID:26601164

  3. Experimental scattershot boson sampling.

    PubMed

    Bentivegna, Marco; Spagnolo, Nicolò; Vitelli, Chiara; Flamini, Fulvio; Viggianiello, Niko; Latmiral, Ludovico; Mataloni, Paolo; Brod, Daniel J; Galvão, Ernesto F; Crespi, Andrea; Ramponi, Roberta; Osellame, Roberto; Sciarrino, Fabio

    2015-04-01

    Boson sampling is a computational task strongly believed to be hard for classical computers, but efficiently solvable by orchestrated bosonic interference in a specialized quantum computer. Current experimental schemes, however, are still insufficient for a convincing demonstration of the advantage of quantum over classical computation. A new variation of this task, scattershot boson sampling, leads to an exponential increase in speed of the quantum device, using a larger number of photon sources based on parametric down-conversion. This is achieved by having multiple heralded single photons being sent, shot by shot, into different random input ports of the interferometer. We report the first scattershot boson sampling experiments, where six different photon-pair sources are coupled to integrated photonic circuits. We use recently proposed statistical tools to analyze our experimental data, providing strong evidence that our photonic quantum simulator works as expected. This approach represents an important leap toward a convincing experimental demonstration of the quantum computational supremacy.

  4. INSTITUTIONS AND BEHAVIOR: EXPERIMENTAL EVIDENCE ON THE EFFECTS OF DEMOCRACY

    PubMed Central

    Bó, Pedro Dal; Foster, Andrew; Putterman, Louis

    2013-01-01

    A novel experiment is used to show that the effect of a policy on the level of cooperation is greater when it is chosen democratically by the subjects than when it is exogenously imposed. In contrast to the previous literature, our experimental design allows us to control for selection effects (e.g. those who choose the policy may be affected differently by it). Our finding implies that democratic institutions may affect behavior directly in addition to having effects through the choice of policies. Our findings have implications for the generalizability of the results of randomized policy interventions. PMID:25076785

  5. Translating evidence-based protocol of wound drain management for total joint arthroplasty into practice: A quasi-experimental study.

    PubMed

    Tsang, Lap Fung; Cheng, Hang Cheong; Ho, Hon Shuen; Hsu, Yung Chak; Chow, Chiu Man; Law, Heung Wah; Fong, Lup Chau; Leung, Lok Ming; Kong, Ivy Ching Yan; Chan, Chi Wai; Sham, Alice So Yuen

    2016-05-01

    Although various drains have long been used in total joint replacement, evidence suggests inconsistent practice exists in the use of drainage systems including intermittently applying suction or free of drainage suction, and variations in the optimal timing for wound drain removal. A comprehensive systematic review of available evidence up to 2013 was conducted in a previous study and a protocol was adapted for clinical application according to the summary of the retrieved information (Tsang, 2015). To determine if the protocol could reduce blood loss and blood transfusion after operation and to develop a record form so as to enhance communication of drainage record amongst surgeons and nurses. A quasi-experimental time-series design was undertaken. In the conventional group, surgeons ordered free drainage if the drain output was more than 300 ml. The time of removal of the drain was based on their professional judgement. In the protocol group the method of drainage was dependant of the drainage output as was the timing of the removal of the drain. A standardized record form was developed to guide operating room and orthopaedic ward nurses to manage the drainage system. The drain was removed significantly earlier in the protocol group. Blood loss rate at the first hour of post-operation was extremely low in the protocol group due to clamping effect. Blood loss in volume during the first three hours in the protocol group was significantly lower than that in the conventional group. Only in 11.1% and 4% of cases was it necessary to clamp at the three and four hour post-operative hours. No clamping was required at the two and eight hour postoperative period. There was no significant difference in blood loss during the removal of the drain and during blood transfusion, which was required for patients upon removal of the drain in the two groups. This is the first clinical study to develop an evidence-based protocol to manage wound drain effectively in Hong Kong. Total

  6. Evidence based general practice: a retrospective study of interventions in one training practice.

    PubMed Central

    Gill, P.; Dowell, A. C.; Neal, R. D.; Smith, N.; Heywood, P.; Wilson, A. E.

    1996-01-01

    OBJECTIVES--To estimate the proportion of interventions in general practice that are based on evidence from clinical trials and to assess the appropriateness of such an evaluation. DESIGN--Retrospective review of case notes. SETTING--One suburban training general practice. SUBJECTS--122 consecutive doctor-patient consultations over two days. MAIN OUTCOME MEASURES--Proportions of interventions based on randomised controlled trials (from literature search with Medline, pharmaceutical databases, and standard textbooks), on convincing non-experimental evidence, and without substantial evidence. RESULTS--21 of the 122 consultations recorded were excluded due to insufficient data; 31 of the interventions were based on randomised controlled trial evidence and 51 based on convincing non-experimental evidence. Hence 82/101 (81%) of interventions were based on evidence meeting our criteria. CONCLUSIONS--Most interventions within general practice are based on evidence from clinical trials, but the methods used in such trials may not be the most appropriate to apply to this setting. PMID:8608291

  7. Vestibular and Oculomotor Physiology: International Meeting of the Barany Society. Volume 374. Annals of the New York Academy of Sciences

    DTIC Science & Technology

    1981-11-06

    A. L. 1968. The Brain Stem of the Cat. University of Wisconsin Press. Madison . Wis. 8. KICVER, 1-. & E. BARRERA. 1953. A method for the combined...Inhibition of central vestibular neurons from the W~ UW % labyrinth and its mediating pathway. 1. NeurophysioL 29: 467-492. S1 MI 1111 t BAME & A. GLWTYN. 1980...revealed lethargy, slow speech, nystagmus, dysmetria, and ataxia. A lumbar puncture at that time showed a spinal fluid protein of 110 mg%, glucose of 15

  8. Experimental Evidence for the Los Alamos Proton Storage Ring Beam Instability

    NASA Astrophysics Data System (ADS)

    Plum, M.; Fitzgerald, D. H.; Macek, R.; Sander, O.; Thiessen, H. A.; Wang, T. S.; Wilkinson, C.

    1997-05-01

    Although the exact instability mechanism at the Proton Storage Ring (PSR) has not yet been conclusively identified, the evidence gathered to date is consistent with an e-p instability. We have recently acquired new data which shows that clearing electrodes significantly affect the instability threshold. A set of comprehensive measurements is also planned for the first months of 1997. In this paper we will present our latest data.

  9. Numerical and experimental evidence of the inter-blade cavitation vortex development at deep part load operation of a Francis turbine

    NASA Astrophysics Data System (ADS)

    Yamamoto, K.; Müller, A.; Favrel, A.; Landry, C.; Avellan, F.

    2016-11-01

    Francis turbines are subject to various types of the cavitation flow depending on the operating conditions. In order to compensate for the stochastic nature of renewable energy sources, it is more and more required to extend the operating range of the generating units, from deep part load to full load conditions. In the deep part load condition, the formation of cavitation vortices in the turbine blade to blade channels called inter-blade cavitation vortex is often observed. The understanding of the dynamic characteristics of these inter-blade vortices and their formation mechanisms is of key importance in an effort of developing reliable flow simulation tools. This paper reports the numerical and experimental investigations carried out in order to establish the vortex characteristics, especially the inception and the development of the vortex structure. The unsteady RANS simulation for the multiphase flow is performed with the SST- SAS turbulence model by using the commercial flow solver ANSYS CFX. The simulation results in terms of the vortex structure and the cavitation volume are evaluated by comparing them to the flow visualizations of the blade channel acquired through a specially instrumented guide vane as well as from the downstream of the runner across the draft tube cone. The inter-blade cavitation vortex is successfully captured by the simulation and both numerical and experimental results evidence that the inter-blade vortices are attached to the runner hub.

  10. Experimental studies of electroweak physics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Etzion, E.

    1997-09-01

    Some experimental new Electroweak physics results measured at the LEP/SLD and the TEVATRON are discussed. The excellent accuracy achieved by the experiments still yield no significant evidence for deviation from the Standard Model predictions, or signal to physics beyond the Standard Model. The Higgs particle still has not been discovered and a low bound is given to its mass.

  11. Theory of simultaneous excitonic-superconductivity condensation II Experimental evidence and stoichiometric interpretations

    NASA Astrophysics Data System (ADS)

    Wong, K. W.; Ching, W. Y.

    1989-04-01

    We discuss a variety of experimental observations which are consistent with theory of the excitonic-enhancement model (EEM) presented earlier. The experimental works discussed are: (1) isotope substitution; (2) fluorinated YBa 2Cu 3O 7- x; (3) infrared optical spectra; (4) specific heat and tunneling gap; (5) Hall effect and nuclear spin relaxation; (6) positron annihilation; (7) utrasound velocity and sound attenuation; (8) Meissner effect and critical current; (9) antiferromagnetism and oxygen deficiency; (10) flux quantization; and (11) photoemission. A simple stoichiometric interpretation on the existing high temperature superconducting oxides based on the specific stacking of chemical subsystems is also presented. It is argued that according to EEM theory, a superconducting oxide must contain two stable oxides, one having excitonic levels such as Cu 2O; the other having intrinsic hole population at the top of the valence band such as CuO. A systematic search for other potential high Tc compounds is also suggested.

  12. Experimental and computational evidence of halogen bonds involving astatine

    NASA Astrophysics Data System (ADS)

    Guo, Ning; Maurice, Rémi; Teze, David; Graton, Jérôme; Champion, Julie; Montavon, Gilles; Galland, Nicolas

    2018-03-01

    The importance of halogen bonds—highly directional interactions between an electron-deficient σ-hole moiety in a halogenated compound and an acceptor such as a Lewis base—is being increasingly recognized in a wide variety of fields from biomedicinal chemistry to materials science. The heaviest halogens are known to form stronger halogen bonds, implying that if this trend continues down the periodic table, astatine should exhibit the highest halogen-bond donating ability. This may be mitigated, however, by the relativistic effects undergone by heavy elements, as illustrated by the metallic character of astatine. Here, the occurrence of halogen-bonding interactions involving astatine is experimentally evidenced. The complexation constants of astatine monoiodide with a series of organic ligands in cyclohexane solution were derived from distribution coefficient measurements and supported by relativistic quantum mechanical calculations. Taken together, the results show that astatine indeed behaves as a halogen-bond donor—a stronger one than iodine—owing to its much more electrophilic σ-hole.

  13. Experimental Evidence of the Knowledge Gap: Message Arousal, Motivation, and Time Delay

    ERIC Educational Resources Information Center

    Grabe, Maria Elizabeth; Yegiyan, Narine; Kamhawi, Rasha

    2008-01-01

    This study experimentally tested the knowledge gap from an information processing perspective. Specifically, knowledge acquisition was investigated under conditions of medium and low news message arousal, with time delay. Results show the persistence of a knowledge gap, particularly for low arousing messages. In fact, at low levels of message…

  14. OA01.25.The first direct experimental evidence correlating ayurveda based tridosha prakriti, with western constitutional psychology somatotypes

    PubMed Central

    Metri, Kashinath G; Bhargav, Hemant; Ramarao, Nagendra Hongasandra; Rizzo-Sierra; Basavakatti, Ramakrishna R

    2012-01-01

    Purpose: Ayurveda is one of the most ancient systems of medical health care. The basic principles, diagnosis of the diseases and their treatment are based on individual prakriti (constitutional type). Ayurveda further classifies the prakriti of an individual on the basis of a set of psychosomatic attributes of personality, depending on whether this individual belongs to Vata, Pitta, or Kapha prakriti, or any combination of them (Patwardhan et al., 2005). The appropriate prakriti assessment is done by several means including questionnaires (Rastogi, 2012; Shilpa and Venkatesha-Murthy, 2011). We aimed to obtain experimental evidence correlating Ayurveda based tridosha-prakriti with western constitutional psychology somatotypes (Rizzo-Sierra, 2011). Method: We employed our Tridosha-prakriti questionnaire (Ramakrishna and Nagendra, 2012), and compared its results with a set of body composition parameters: Height, body weight, body mass index (BMI), muscle mass, fat mass, and fat percentage in normal healthy volunteers (25 males and 25 females, mean age was 26 (± 4) and 25 (± 6) years respectively). Moreover, two-tailed Pearson's correlations were investigated to match the extreme prakriti types with the western constitutional psychology somatotypes, through the mentioned body composition measures. Result: Significant negative correlations were observed between the percentage of Vata attributes as per the questionnaire in the individuals and their BMI, body weight and fat mass respectively (p<0.05). Similarly, there was a significant positive correlation between the percentage of Pitta attributes with the height, body weight, and muscle mass respectively. Also, a significant positive correlation was observed between the percentage of Kapha attributes with fat mass and fat percentage, along with a negative correlation with height. Conclusion: We provide evidence-linking Ayurveda to modern constitutional psychology. In this way, a concept such as prakriti is suggested

  15. Anomalous Evidence, Confidence Change, and Theory Change.

    PubMed

    Hemmerich, Joshua A; Van Voorhis, Kellie; Wiley, Jennifer

    2016-08-01

    A novel experimental paradigm that measured theory change and confidence in participants' theories was used in three experiments to test the effects of anomalous evidence. Experiment 1 varied the amount of anomalous evidence to see if "dose size" made incremental changes in confidence toward theory change. Experiment 2 varied whether anomalous evidence was convergent (of multiple types) or replicating (similar finding repeated). Experiment 3 varied whether participants were provided with an alternative theory that explained the anomalous evidence. All experiments showed that participants' confidence changes were commensurate with the amount of anomalous evidence presented, and that larger decreases in confidence predicted theory changes. Convergent evidence and the presentation of an alternative theory led to larger confidence change. Convergent evidence also caused more theory changes. Even when people do not change theories, factors pertinent to the evidence and alternative theories decrease their confidence in their current theory and move them incrementally closer to theory change. Copyright © 2015 Cognitive Science Society, Inc.

  16. Evidence for stable grain boundary melt films in experimentally deformed olivine-orthopyroxene rocks

    NASA Astrophysics Data System (ADS)

    de Kloe, R.; Drury, M. R.; van Roermund, H. L. M.

    The microstructure of olivine-olivine grain boundaries has been studied in experimentally deformed (1200-1227°C, 300MPa) partially molten olivine and olivine-orthopyroxene rocks. In-situ melting produced 1vol% melt in all samples studied. Grain boundary analyses were carried out using a number of transmission electron microscopy techniques. The grain boundary chemistry in undeformed olivine-orthopyroxene starting material showed evidence for the presence of an intergranular phase along some, but not all, of the olivine-olivine boundaries. In the deformed samples, ultrathin Si-rich, Al- and Ca-bearing amorphous films have been observed along all investigated olivine-olivine grain boundaries. The chemistry of the grain boundaries, which is considered to be indicative for the presence of a thin film, was measured with energy-dispersive X-ray spectroscopy (EDX) and energy-filtering imaging. The amorphous nature of the films was confirmed with diffuse dark field imaging, Fresnel fringe imaging, and high-resolution electron microscopy. The films range in thickness from 0.6 to 3.0nm, and EDX analyses show that the presence of Al and Ca is restricted to this ultrathin film along the grain boundaries. Because thin melt films have been observed in all the samples, they are thought to be stable features of the melt microstructure in deformed partially molten rocks. The transition from the occasional presence of films in the undeformed starting material to the general occurrence of the films in deformed materials suggests that deformation promotes the formation and distribution of the films. Alternatively, hot-pressing may be too short for films to develop along all grain boundaries. A difference in creep strength between the studied samples could not be attributed to grain boundary melt films, as these have been found in all deformed samples. However, a weakening effect of grain boundary melt films on olivine rheology could not be ruled out due to the lack of confirmed melt

  17. Criminogenic Effects of the Prison Environment on Inmate Behavior: Some Experimental Evidence

    ERIC Educational Resources Information Center

    Camp, Scott D.; Gaes, Gerald G.

    2005-01-01

    The current study analyzed a subset of the experimental data collected by Berk, Ladd, Graziano, and Baek (2003) to test whether different intensities of incarceration make inmates more criminal while incarcerated. There were 561 male inmates whose equivalent classification scores indicated they had the same level of risk to commit institutional…

  18. Experimental evidence that microbial activity lowers the albedo of glacier surfaces: the cryoconite casserole experiment.

    NASA Astrophysics Data System (ADS)

    Musilova, M.; Tranter, M.; Takeuchi, N.; Anesio, A. M.

    2014-12-01

    Darkened glacier and ice sheet surfaces have lower albedos, absorb more solar radiation and consequently melt more rapidly. The increase in glacier surface darkening is an important positive feedback to warming global temperatures, leading to ever growing world-wide ice mass loss. Most studies focus primarily on glacial albedo darkening caused by the physical properties of snow and ice surfaces, and the deposition of dark impurities on glaciers. To date, however, the important effects of biological activity have not been included in most albedo reduction models. This study provides the first experimental evidence that microbial activity can significantly decrease the albedo of glacier surfaces. An original laboratory experiment, the cryoconite casserole, was designed to test the microbial darkening of glacier surface debris (cryoconite) under simulated Greenlandic summer conditions. It was found that minor fertilisation of the cryoconite (at nutrient concentrations typical of glacial ice melt) stimulated extensive microbial activity. Microbes intensified their organic carbon fixation and even mined phosphorous out of the glacier surface sediment. Furthermore, the microbial organic carbon production, accumulation and transformation caused the glacial debris to darken further by 17.3% reflectivity (albedo analogue). These experiments are consistent with the hypothesis that enhanced fertilisation by anthropogenic inputs results in substantial amounts of organic carbon fixation, debris darkening and ultimately to a considerable decrease in the ice albedo of glacier surfaces on global scales. The sizeable amounts of microbially produced glacier surface organic matter and nutrients can thus be a vital source of bioavailable nutrients for subglacial and downstream environments.

  19. Secondary school physics teachers' conceptions of scientific evidence: A collective case study

    NASA Astrophysics Data System (ADS)

    Taylor, Joseph A.

    Engaging secondary school students in inquiry-oriented tasks that more closely simulate the scholarly activities of scientists has been recommended as a way to improve scientific literacy. Two tasks that are frequently recommended include students' design of original experiments, and students' evaluation of scientific evidence and conclusions. Yet, little is known about teachers' conceptions of experimentation. The principal aim of this study, therefore, was to describe the nature of prospective and practicing physics teachers' conceptions of scientific evidence. More specifically, the following research questions guided this study: (1) What types of issues related to the measurement reliability and experimental validity of scientific evidence do practicing and prospective physics teachers think about when designing experiments? (2) When presented with hypothetical scenarios that describe unsound experimental procedures or poorly supported conclusions (or both), what concerns will prospective and practicing physics teachers raise? And (3) When the participants' responses to parallel research prompts are compared across protocols, what similarities and differences exist? The nature of the teacher-participants' conceptions was described from an analysis of data collected from research prompts such as interviews and hand written artifacts. In these research prompts, the teachers "thought aloud" while designing experiments and critically evaluated student-collected evidence presented in hypothetical classroom scenarios. The data from this study suggested that the three teachers, while contemplating the reliability and validity of scientific evidence, frequently used their conceptions of evidence in conjunction with specific subject matter conceptions. The data also indicated that the relationship between subject matter knowledge and conceptions of evidence was more pronounced for some conceptions of evidence than for others. Suggestions for future research included

  20. Selective Cooperation in the Supermarket : Field Experimental Evidence for Indirect Reciprocity.

    PubMed

    Lange, Florian; Eggert, Frank

    2015-12-01

    Numerous laboratory experiments suggest that mechanisms of indirect reciprocity might account for human cooperation. However, conclusive field data supporting the predictions of indirect reciprocity in everyday life situations is still scarce. Here, we attempt to compensate for this lack by examining the determinants of cooperative behavior in a German supermarket. Our methods were as follows: Confederates of the experimenter lined up at the checkout, apparently to buy a single item. As an act of cooperation, the waiting person in front (the potential helper) could allow the confederate to go ahead. By this means, the potential helper could take a cost (additional waiting time) by providing the confederate with a benefit (saved waiting time). We recorded the potential helpers' behavior and the number of items they purchased as a quantitative measure proportional to the confederate's benefit. Moreover, in a field experimental design, we varied the confederates' image by manipulating the item they purchased (beer vs. water). As predicted, the more waiting time they could save, the more likely the confederates were to receive cooperation. This relationship was moderated by the confederates' image. Cost-to-benefit ratios were required to be more favorable for beer-purchasing individuals to receive cooperation. Our results demonstrate that everyday human cooperation can be studied unobtrusively in the field and that cooperation among strangers is selective in a way that is consistent with current models of indirect reciprocity.

  1. Reaction time effects in lab- versus Web-based research: Experimental evidence.

    PubMed

    Hilbig, Benjamin E

    2016-12-01

    Although Web-based research is now commonplace, it continues to spur skepticism from reviewers and editors, especially whenever reaction times are of primary interest. Such persistent preconceptions are based on arguments referring to increased variation, the limits of certain software and technologies, and a noteworthy lack of comparisons (between Web and lab) in fully randomized experiments. To provide a critical test, participants were randomly assigned to complete a lexical decision task either (a) in the lab using standard experimental software (E-Prime), (b) in the lab using a browser-based version (written in HTML and JavaScript), or (c) via the Web using the same browser-based version. The classical word frequency effect was typical in size and corresponded to a very large effect in all three conditions. There was no indication that the Web- or browser-based data collection was in any way inferior. In fact, if anything, a larger effect was obtained in the browser-based conditions than in the condition relying on standard experimental software. No differences between Web and lab (within the browser-based conditions) could be observed, thus disconfirming any substantial influence of increased technical or situational variation. In summary, the present experiment contradicts the still common preconception that reaction time effects of only a few hundred milliseconds cannot be detected in Web experiments.

  2. Diverse convergent evidence in the genetic analysis of complex disease: coordinating omic, informatic, and experimental evidence to better identify and validate risk factors

    PubMed Central

    2014-01-01

    In omic research, such as genome wide association studies, researchers seek to repeat their results in other datasets to reduce false positive findings and thus provide evidence for the existence of true associations. Unfortunately this standard validation approach cannot completely eliminate false positive conclusions, and it can also mask many true associations that might otherwise advance our understanding of pathology. These issues beg the question: How can we increase the amount of knowledge gained from high throughput genetic data? To address this challenge, we present an approach that complements standard statistical validation methods by drawing attention to both potential false negative and false positive conclusions, as well as providing broad information for directing future research. The Diverse Convergent Evidence approach (DiCE) we propose integrates information from multiple sources (omics, informatics, and laboratory experiments) to estimate the strength of the available corroborating evidence supporting a given association. This process is designed to yield an evidence metric that has utility when etiologic heterogeneity, variable risk factor frequencies, and a variety of observational data imperfections might lead to false conclusions. We provide proof of principle examples in which DiCE identified strong evidence for associations that have established biological importance, when standard validation methods alone did not provide support. If used as an adjunct to standard validation methods this approach can leverage multiple distinct data types to improve genetic risk factor discovery/validation, promote effective science communication, and guide future research directions. PMID:25071867

  3. Experimental Trials and "What Works?" in Education: The Case of Grammar for Writing

    ERIC Educational Resources Information Center

    Wyse, Dominic; Torgerson, Carole

    2017-01-01

    The place of evidence to inform educational effectiveness has received increasing attention internationally in the last two decades. An important contribution to evidence-informed policy has been greater attention to experimental trials including randomised controlled trials (RCTs). The aim of this paper is to examine the use of evidence,…

  4. Where Does Good Evidence Come from?

    ERIC Educational Resources Information Center

    Gorard, Stephen; Cook, Thomas

    2007-01-01

    This article started as a debate between the two authors. Both authors present a series of propositions about quality standards in education research. Cook's propositions, as might be expected, not only concern the importance of experimental trials for establishing the security of causal evidence, but also include some important practical and…

  5. Evidence for Future Cognition in Animals

    ERIC Educational Resources Information Center

    Roberts, William A.

    2012-01-01

    Evidence concerning the possibility of mental time travel into the future by animals was reviewed. Both experimental laboratory studies and field observations were considered. Paradigms for the study of future anticipation and planning included inhibition of consumption of current food contingent on future receipt of either a larger quantity or…

  6. Endocrine-disrupting chemicals and risk of diabetes: an evidence-based review.

    PubMed

    Lind, P Monica; Lind, Lars

    2018-05-09

    The purpose of this study was to review the epidemiological and experimental evidence linking background exposure to a selection of environmental endocrine-disrupting chemicals (EDCs) with diabetes and impaired glucose metabolism. The review summarises the literature on both cross-sectional and prospective studies in humans, as well as experimental in vivo and in vitro studies. The findings were subjected to evidence grading according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) classification. We found >40 cross-sectional and seven prospective studies regarding EDCs and risk of diabetes. Taken together, there is moderate evidence for a relationship between exposure to dichlorodiphenyldichloroethylene (p,p'-DDE), a metabolite of the pesticide dichlorodiphenyltrichloroethane, and diabetes development. Regarding polychlorinated biphenyls (PCBs), it is likely that the rodent models used are not appropriate, and therefore the evidence is poorer than for p,p'-DDE. For other EDCs, such as bisphenol A, phthalates and perfluorinated chemicals, the evidence is scarce, since very few prospective studies exist. Brominated flame retardants do not seem to be associated with a disturbed glucose tolerance. Thus, evidence is accumulating that EDCs might be involved in diabetes development. Best evidence exists for p,p'-DDE. For other chemicals, both prospective studies and supporting animal data are still lacking.

  7. Verb Form Indicates Discourse Segment Type in Biological Research Papers: Experimental Evidence

    ERIC Educational Resources Information Center

    de Waard, Anita; Maat, Henk Pander

    2012-01-01

    Corpus studies suggest that verb tense is a differentiating feature between, on the one hand, text pertaining to experimental results (involving methods and results) and on the other hand, text pertaining to more abstract concepts (i.e. regarding background knowledge in a field, hypotheses, problems or claims). In this paper, we describe a user…

  8. Persistence of Learning Gains from Computer Assisted Learning: Experimental Evidence from China

    ERIC Educational Resources Information Center

    Mo, D.; Zhang, L.; Wang, J.; Huang, W.; Shi, Y.; Boswell, M.; Rozelle, S.

    2015-01-01

    Computer assisted learning (CAL) programs have been shown to be effective in improving educational outcomes. However, the existing studies on CAL have almost all been conducted over a short period of time. There is very little evidence on how the impact evolves over time. In response, we conducted a clustered randomized experiment involving 2741…

  9. Memory for Scientific Arguments and Their Sources: Claim-Evidence Consistency Matters

    ERIC Educational Resources Information Center

    Steffens, Brent; Britt, M. Anne; Braasch, Jason L.; Strømsø, Helge; Bråten, Ivar

    2014-01-01

    We investigated whether memory for scientific arguments and their sources were affected by the appropriateness of the claim-evidence relationship. Undergraduates read health articles in one of four conditions derived by crossing claim type (causal with definite qualifier, associative with tentative qualifier) and evidence type (experimental,…

  10. Experimental evidence of solitary wave interaction in Hertzian chains

    NASA Astrophysics Data System (ADS)

    Santibanez, Francisco; Munoz, Romina; Caussarieu, Aude; Job, Stéphane; Melo, Francisco

    2011-08-01

    We study experimentally the interaction between two solitary waves that approach one another in a linear chain of spheres interacting via the Hertz potential. When these counterpropagating waves collide, they cross each other and a phase shift in respect to the noninteracting waves is introduced as a result of the nonlinear interaction potential. This observation is well reproduced by our numerical simulations and is shown to be independent of viscoelastic dissipation at the bead contact. In addition, when the collision of equal amplitude and synchronized counterpropagating waves takes place, we observe that two secondary solitary waves emerge from the interacting region. The amplitude of the secondary solitary waves is proportional to the amplitude of incident waves. However, secondary solitary waves are stronger when the collision occurs at the middle contact in chains with an even number of beads. Although numerical simulations correctly predict the existence of these waves, experiments show that their respective amplitudes are significantly larger than predicted. We attribute this discrepancy to the rolling friction at the bead contact during solitary wave propagation.

  11. QED: Experimental Evidence

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lincoln, Don

    The theory of quantum electrodynamics (QED) is perhaps the most precisely tested physics theory ever conceived. It describes the interaction of charged particles by emitting photons. The most precise prediction of this very precise theory is the magnetic strength of the electron, what physicists call the magnetic moment. Prediction and measurement agree to 12 digits of precision. In this video, Fermilab’s Dr. Don Lincoln talks about this amazing measurement.

  12. QED: Experimental Evidence

    ScienceCinema

    Lincoln, Don

    2018-01-16

    The theory of quantum electrodynamics (QED) is perhaps the most precisely tested physics theory ever conceived. It describes the interaction of charged particles by emitting photons. The most precise prediction of this very precise theory is the magnetic strength of the electron, what physicists call the magnetic moment. Prediction and measurement agree to 12 digits of precision. In this video, Fermilab’s Dr. Don Lincoln talks about this amazing measurement.

  13. Experimental hypervigilance changes the intensity/unpleasantness ratio of pressure sensations: evidence for the generalized hypervigilance hypothesis.

    PubMed

    Hollins, Mark; Walters, Sloan

    2016-06-01

    Patients with chronic pain conditions such as fibromyalgia often demonstrate hypervigilance-undue alertness for unpleasant or threatening bodily sensations-as well as enhancement of these sensations. The generalized hypervigilance hypothesis (GHH) of Rollman and colleagues asserts that hypervigilance leads to this perceptual amplification. However, cause-and-effect relationships are difficult to establish in studies using a quasi-experimental design. In the present study, we sought to address this issue by attempting to induce hypervigilance experimentally, in one of two groups to which young, healthy adults had been randomly assigned. Those in the experimental group wrote about the flu and practiced counting their own blinks, breaths, and heartbeats; those in the control group wrote about a neutral topic and counted innocuous lights and sounds. Next, both groups rated the intensity and unpleasantness of pressure sensations (ranging from mild to painful) caused by a series of applications of a weighted rod to the forearm. The intensity/unpleasantness ratio of these ratings was significantly greater in the experimental group, suggesting that induced hypervigilance had caused perceptual amplification that generalized to pressure sensations, which had not been part of the experimental manipulation. Psychometric measures of anxiety and catastrophizing were equivalent in the two groups, indicating that the experimental manipulation operated via attentional rather than emotional changes. The results support the GHH.

  14. Questioning the application of risk of bias tools in appraising evidence from natural experimental studies: critical reflections on Benton et al., IJBNPA 2016.

    PubMed

    Humphreys, David K; Panter, Jenna; Ogilvie, David

    2017-04-19

    We recently read the article by Benton et al. which reviewed risk of bias in natural experimental studies investigating the impact of the built environment on physical activity (Benton et al., 2016; Int J Behav Nutr Phys Act 13:107). As a technical exercise in assessing risk of bias to understand study quality, we found the results of this study both interesting and potentially useful. However, it prompted a number of concerns with the use of risk of bias tools for assessing the quality of evidence from studies exploiting natural experiments. As we discuss in this commentary, the rigid application of such tools could have adverse effects on the uptake and use of natural experiments in population health research and practice.

  15. Benzodiazepines, opioids and driving: an overview of the experimental research.

    PubMed

    Leung, Stefanie Y

    2011-05-01

    Road crashes contribute significantly to the total burden of injury in Australia, with the risk of injury being associated with the presence of drugs and/or alcohol in the driver's blood. Increasingly, some of the most commonly detected drugs include prescription medicines, the most notable of these being benzodiazepines and opioids. However, there is a paucity of experimental research into the effects of prescribed psychoactive drugs on driving behaviours. This paper provides an overview of experimental studies investigating the effects of prescribed doses of benzodiazepines and opioids on driving ability, and points to future directions for research. There is growing epidemiological evidence linking the therapeutic use of benzodiazepines and opioids to an increased crash risk. However, the current experimental literature remains unclear. Limitations to study methodologies have resulted in inconsistent findings. Limited experimental evidence exists to inform policy and guidelines regarding fitness-to-drive for patients taking prescribed benzodiazepines and opioids. Further experimental research is required to elucidate the effects of these medications on driving, under varying conditions and in different medical contexts. This will ensure that doctors prescribing benzodiazepines and opioids are well informed, and can appropriately advise patients of the risks associated with driving whilst taking these medications. © 2011 Australasian Professional Society on Alcohol and other Drugs.

  16. Experimental evidence of nitrous acid formation in the electron beam treatment of flue gas

    NASA Astrophysics Data System (ADS)

    Mätzing, H.; Namba, H.; Tokunaga, O.

    1994-03-01

    In the Electron Beam Dry Scrubbing (EBDS) process, flue gas from fossil fuel burning power plants is irradiated with accelerated (300-800 keV) electrons. Thereby, nitrogen oxide (NO x) and sulfur dioxide (SO 2) traces are transformed into nitric and sulfuric acids, respectively, which are converted into particulate ammonium nitrate and sulfate upon the addition of ammonia. The powdery can be filtered from the main gas stream and can be sold as agricultural fertilizer. A lot of experimental investigations have been performed on the EBDS process and computer models have been developed to interpret the experimental results and to predict economic improvements. According to the model calculations, substantial amounts of intermediate nitrous acid (HNO 2) are formed in the electron beam treatment of flue gas. However, no corresponding experimental information is available so far. Therefore, we have undertaken the first experimental investigation about the formation of nitrous acid in an irradiated mixture of NO in synthetic air. Under these conditions, aerosol formation is avoided. UV spectra of the irradiated gas were recorded in the wavelength range λ = 345-375 nm. Both NO 2 and HNO 2 have characteristic absorption bands in this wavelength range. Calibration spectra of NO 2 were subtracted from the sample spectra. The remaining absorption bands can clearly be assigned to nitrous acid. The concentration of nitrous acid was determined by differential optical absorption. It was found lower than the model prediction. The importance of nitrous acid formation in the EBDS process needs to be clarified.

  17. Experimental evidence for negative turgor pressure in small leaf cells of Robinia pseudoacacia L versus large cells of Metasequoia glyptostroboides Hu et W.C.Cheng. 1. Evidence from pressure-volume curve analysis of dead tissue.

    PubMed

    Yang, Dongmei; Pan, Shaoan; Ding, Yiting; Tyree, Melvin T

    2017-03-01

    This paper provides a mini-review of evidence for negative turgor pressure in leaf cells starting with experimental evidence in the late 1950s and ending with biomechanical models published in 2014. In the present study, biomechanical models were used to predict how negative turgor pressure might be manifested in dead tissue, and experiments were conducted to test the predictions. The main findings were as follows: (i) Tissues killed by heating to 60 or 80 °C or by freezing in liquid nitrogen all became equally leaky to cell sap solutes and all seemed to pass freely through the cell walls. (ii) Once cell sap solutes could freely pass the cell walls, the shape of pressure-volume curves was dramatically altered between living and dead cells. (iii) Pressure-volume curves of dead tissue seem to measure negative turgor defined as negative when inside minus outside pressure is negative. (iv) Robinia pseudoacacia leaves with small palisade cells had more negative turgor than Metasequoia glyptostroboides with large cells. (v) The absolute difference in negative turgor between R. pseudoacacia and M. glyptostroboides approached as much as 1.0 MPa in some cases. The differences in the manifestation of negative turgor in living versus dead tissue are discussed. © 2016 John Wiley & Sons Ltd.

  18. Wundt, Völkerpsychologie, and experimental social psychology.

    PubMed

    Greenwood, John D

    2003-02-01

    Wilhelm Wundt distinguished between "experimental psychology" and Volkerpsychologie. It is often claimed that Wundt maintained that social psychological phenomena, the subject matter of Völkerpsychologie, could not be investigated experimentally but must be explored via comparative-historical methods. In this article it is argued that it is doubtful if many of the passages usually cited as evidence that Wundt held such a view actually such such a view. It is also argued that if Wundt did hold such a view, it was inconsistent with his own general theoretical position and methodological practice. It is suggested that it is anachronistic to attribute such a view to Wundt, because he appears to have had little interest in the experimental analysis of the synchronic social dynamics of psychological processes. Most of Wundt's arguments about the inappropriateness of experimentation were directed against the introspective analysis of diachronic historical processes.

  19. Chronic Histopathological and Behavioral Outcomes of Experimental Traumatic Brain Injury in Adult Male Animals

    PubMed Central

    Osier, Nicole D.; Carlson, Shaun W.; DeSana, Anthony

    2015-01-01

    Abstract The purpose of this review is to survey the use of experimental animal models for studying the chronic histopathological and behavioral consequences of traumatic brain injury (TBI). The strategies employed to study the long-term consequences of TBI are described, along with a summary of the evidence available to date from common experimental TBI models: fluid percussion injury; controlled cortical impact; blast TBI; and closed-head injury. For each model, evidence is organized according to outcome. Histopathological outcomes included are gross changes in morphology/histology, ventricular enlargement, gray/white matter shrinkage, axonal injury, cerebrovascular histopathology, inflammation, and neurogenesis. Behavioral outcomes included are overall neurological function, motor function, cognitive function, frontal lobe function, and stress-related outcomes. A brief discussion is provided comparing the most common experimental models of TBI and highlighting the utility of each model in understanding specific aspects of TBI pathology. The majority of experimental TBI studies collect data in the acute postinjury period, but few continue into the chronic period. Available evidence from long-term studies suggests that many of the experimental TBI models can lead to progressive changes in histopathology and behavior. The studies described in this review contribute to our understanding of chronic TBI pathology. PMID:25490251

  20. Implicit negotiation beliefs and performance: experimental and longitudinal evidence.

    PubMed

    Kray, Laura J; Haselhuhn, Michael P

    2007-07-01

    The authors argue that implicit negotiation beliefs, which speak to the expected malleability of negotiating ability, affect performance in dyadic negotiations. They expected negotiators who believe negotiating attributes are malleable (incremental theorists) to outperform negotiators who believe negotiating attributes are fixed (entity theorists). In Study 1, they gathered evidence of convergent and discriminant validity for the implicit negotiation belief construct. In Study 2, they examined the impact of implicit beliefs on the achievement goals that negotiators pursue. In Study 3, they explored the causal role of implicit beliefs on negotiation performance by manipulating negotiators' implicit beliefs within dyads. They also identified perceived ability as a moderator of the link between implicit negotiation beliefs and performance. In Study 4, they measured negotiators' beliefs in a classroom setting and examined how these beliefs affected negotiation performance and overall performance in the course 15 weeks later. Across all performance measures, incremental theorists outperformed entity theorists. Consistent with the authors' hypotheses, incremental theorists captured more of the bargaining surplus and were more integrative than their entity theorist counterparts, suggesting implicit theories are important determinants of how negotiators perform. Implications and future directions are discussed. Copyright 2007 APA, all rights reserved.

  1. Too good to be true: publication bias in two prominent studies from experimental psychology.

    PubMed

    Francis, Gregory

    2012-04-01

    Empirical replication has long been considered the final arbiter of phenomena in science, but replication is undermined when there is evidence for publication bias. Evidence for publication bias in a set of experiments can be found when the observed number of rejections of the null hypothesis exceeds the expected number of rejections. Application of this test reveals evidence of publication bias in two prominent investigations from experimental psychology that have purported to reveal evidence of extrasensory perception and to indicate severe limitations of the scientific method. The presence of publication bias suggests that those investigations cannot be taken as proper scientific studies of such phenomena, because critical data are not available to the field. Publication bias could partly be avoided if experimental psychologists started using Bayesian data analysis techniques.

  2. Histological and serological evidence of experimental paracoccidioidomycosis in Calomys callosus (Rodentia: Cricetidae)

    PubMed Central

    Berbert, Alceu LCV; Faria, Gabriele G; Gennari-Cardoso, Margareth L; Silva, Maria MMD; Mineo, José R; Loyola, Adriano M

    2007-01-01

    The responses of animal experimental models related to the infectivity, virulence and pathogenicity of Paracoccidioides brasiliensis is constantly used to develop new perspectives of investigation. The rodent Calomys callosus, Rengger 1830 (Rodentia: Cricetidae) is an indigenous inhabitant of the savannah environment found in the central regions of Brazil. The aim of the present work was to evaluate the histopathological and serological features of C. callosus after inoculation with the Pb18 strain of P. brasiliensis. Furthermore, A/Sn and B10.A mice strains were also tested to compare the results obtained in C. callosus to these well-established experimental models of resistance and susceptibility respectively. In every instance, survival analysis was performed, and histopathological study of the lungs, liver and spleen was employed to investigate tissue involvement, degree of inflammation and fungal presence. Levels of antibodies to P. brasiliensis were measured by using an enzyme-linked immunosorbent assay after 4 weeks and at the advanced stage of infection. The mortality rate was proportional to inoculation dose in all groups, but overall it was much superior in C. callosus than in the B10.A-susceptible mice. Macroscopical and microscopical pathological alterations were also more extensive and remarkable for C. callosus, once again proportional to inoculation dose, but more noticeable differences among the studied groups were found with 0.6 × 105 inoculum. In addition, the serological profile of C. callosus was similar to that found for B10.A-susceptible mice. Infection of C. callosus with 0.6 × 108 Pb18 inoculum resulted in more serious illness, and it decreased in severity in proportion to the inoculum dose. This difference was more pronounced in C. callosus, and the clinical, serological and pathological findings in this animal were more intense and precocious compared with the B10.A-susceptible mice. The present results suggest that C. callosus is a

  3. From randomized controlled trials to evidence grading schemes: current state of evidence-based practice in social sciences.

    PubMed

    Boruch, Robert; Rui, Ning

    2008-11-01

    With the advance of web search and navigation technology, enormous amount of information, non-information, and misinformation may be obtained in milliseconds in response to questions about 'what works' in social sciences. Today, policy makers in non-medical public service arenas are under increasing pressure to make sound decisions based on scientific evidence. Some of these decisions are a matter of legal requirement. This paper shows how such movements are closely aligned with the evolution of organizations that develop and apply evidence standards and evidence grading schemes within the social science communities. The current state of evidence-based practice in social sciences is examined by reviewing the latest development of randomized trials and evidence grading schemes in the fields of education, criminal justice, and social welfare. Studies conducted under the auspices of the Campbell Collaboration and What Works Clearinghouse are used to illustrate ingredients of evidence grading schemes, graphic display of results of systematic reviews, and discrepancies of evidence derived from randomized trials and non-experimental trials. Furthermore, it is argued that the use of evidence on 'what works' depends on the potential users' awareness, understanding of the evidence, as well as their capacity and willingness to use it. Awareness and understanding depends on the world wide web and its augmentations, while capacity and willingness depends more on incentives to use good evidence and on political and ethical values. Implications for the future development of evidence grading organizations are discussed. © 2008 Blackwell Publishing Asia Pty Ltd and Chinese Cochrane Center, West China Hospital of Sichuan University.

  4. Growing evidence for human health benefits of boron

    USDA-ARS?s Scientific Manuscript database

    Growing evidence from numerous laboratories using a variety of experimental models shows that boron is a bioactive beneficial, perhaps essential, element for humans. Reported beneficial actions of boron include arthritis alleviation or risk reduction; bone growth and maintenance; central nervous sys...

  5. An experimental study on providing a scientific evidence for seven-time alcohol-steaming of Rhei Rhizoma when clinically used.

    PubMed

    Sim, Yeomoon; Oh, Hyein; Oh, Dal-Seok; Kim, Namkwon; Gu, Pil Sung; Choi, Jin Gyu; Kim, Hyo Geun; Kang, Tong Ho; Oh, Myung Sook

    2015-10-27

    Rhei Rhizoma (RR) has been widely used as laxative and processed to alter its therapeutic actions or reduce its side effects. In this study, we evaluated experimentally the clinical application guideline that RR should be alcohol-steamed seven times before being used in elderly patients, as described in Dongeuibogam, the most famous book on Korean traditional medicine. Unprocessed RR (RR-U) was soaked in rice wine, steamed and then fully dried (RR-P1). The process was repeated four (RR-P4) or seven times (RR-P7). Reversed-phase high-performance liquid chromatography was used to determine the RR-U, RR-P1, RR-P4 and RR-P7 (RRs) constituents. To evaluate the effect of RRs on liver toxicity, human hepatoma cells (HepG2) were treated with RRs at 100 μg/mL for 4 h and then cell viabilities were measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. To confirm the effects in vivo, 5-week-old male Sprague-Dawley rats were treated with RRs at 3 g/kg/day for 21 days. Body weight and serum biochemical parameters were measured and liver histology was assessed. The levels of sennosides decreased in processed RRs in an iteration-dependent manner, while the emodin level was unaffected. In HepG2 cells, cell viability was reduced with RR-U, while the toxicity decreased according to the number of processing cycles. The changes in body weight, relative liver weight and liver enzymes of RR-U-treated rats were reduced in processed RRs-treated rats. Histopathological analysis indicated swelling and cholestasis improved following seven times alcohol-steaming cycles. These results provide experimental evidence that RR-P7 almost completely reduces RR hepatotoxicity.

  6. Experimental evidence for the ancestry of allotetraploid Trifolium repens and creation of synthetic forms with value for plant breeding.

    PubMed

    Williams, Warren M; Ellison, Nicholas W; Ansari, Helal A; Verry, Isabelle M; Hussain, S Wajid

    2012-04-24

    White clover (Trifolium repens) is a ubiquitous weed of the temperate world that through use of improved cultivars has also become the most important legume of grazed pastures world-wide. It has long been suspected to be allotetraploid, but the diploid ancestral species have remained elusive. Putative diploid ancestors were indicated by DNA sequence phylogeny to be T. pallescens and T. occidentale. Here, we use further DNA evidence as well as a combination of molecular cytogenetics (FISH and GISH) and experimental hybridization to test the hypothesis that white clover originated as a hybrid between T. pallescens and T. occidentale. T. pallescens plants were identified with chloroplast trnL intron DNA sequences identical to those of white clover. Similarly, T. occidentale plants with nuclear ITS sequences identical to white clover were also identified. Reciprocal GISH experiments, alternately using labeled genomic DNA probes from each of the putative ancestral species on the same white clover cells, showed that half of the chromosomes hybridized with each probe. F1 hybrids were generated by embryo rescue and these showed strong interspecific chromosome pairing and produced a significant frequency of unreduced gametes, indicating the likely mode of polyploidization. The F1 hybrids are inter-fertile with white clover and function as synthetic white clovers, a valuable new resource for the re-incorporation of ancestral genomes into modern white clover for future plant breeding. Evidence from DNA sequence analyses, molecular cytogenetics, interspecific hybridization and breeding experiments supports the hypothesis that a diploid alpine species (T. pallescens) hybridized with a diploid coastal species (T. occidentale) to generate tetraploid T. repens. The coming together of these two narrowly adapted species (one alpine and the other maritime), along with allotetraploidy, has led to a transgressive hybrid with a broad adaptive range.

  7. The Evidence and Conclusion Ontology (ECO): Supporting GO Annotations.

    PubMed

    Chibucos, Marcus C; Siegele, Deborah A; Hu, James C; Giglio, Michelle

    2017-01-01

    The Evidence and Conclusion Ontology (ECO) is a community resource for describing the various types of evidence that are generated during the course of a scientific study and which are typically used to support assertions made by researchers. ECO describes multiple evidence types, including evidence resulting from experimental (i.e., wet lab) techniques, evidence arising from computational methods, statements made by authors (whether or not supported by evidence), and inferences drawn by researchers curating the literature. In addition to summarizing the evidence that supports a particular assertion, ECO also offers a means to document whether a computer or a human performed the process of making the annotation. Incorporating ECO into an annotation system makes it possible to leverage the structure of the ontology such that associated data can be grouped hierarchically, users can select data associated with particular evidence types, and quality control pipelines can be optimized. Today, over 30 resources, including the Gene Ontology, use the Evidence and Conclusion Ontology to represent both evidence and how annotations are made.

  8. Climate warming drives local extinction: Evidence from observation and experimentation.

    PubMed

    Panetta, Anne Marie; Stanton, Maureen L; Harte, John

    2018-02-01

    Despite increasing concern about elevated extinction risk as global temperatures rise, it is difficult to confirm causal links between climate change and extinction. By coupling 25 years of in situ climate manipulation with experimental seed introductions and both historical and current plant surveys, we identify causal, mechanistic links between climate change and the local extinction of a widespread mountain plant ( Androsace septentrionalis ). Climate warming causes precipitous declines in population size by reducing fecundity and survival across multiple life stages. Climate warming also purges belowground seed banks, limiting the potential for the future recovery of at-risk populations under ameliorated conditions. Bolstered by previous reports of plant community shifts in this experiment and in other habitats, our findings not only support the hypothesis that climate change can drive local extinction but also foreshadow potentially widespread species losses in subalpine meadows as climate warming continues.

  9. Experimental evidence for excess entropy discontinuities in glass-forming solutions.

    PubMed

    Lienhard, Daniel M; Zobrist, Bernhard; Zuend, Andreas; Krieger, Ulrich K; Peter, Thomas

    2012-02-21

    Glass transition temperatures T(g) are investigated in aqueous binary and multi-component solutions consisting of citric acid, calcium nitrate (Ca(NO(3))(2)), malonic acid, raffinose, and ammonium bisulfate (NH(4)HSO(4)) using a differential scanning calorimeter. Based on measured glass transition temperatures of binary aqueous mixtures and fitted binary coefficients, the T(g) of multi-component systems can be predicted using mixing rules. However, the experimentally observed T(g) in multi-component solutions show considerable deviations from two theoretical approaches considered. The deviations from these predictions are explained in terms of the molar excess mixing entropy difference between the supercooled liquid and glassy state at T(g). The multi-component mixtures involve contributions to these excess mixing entropies that the mixing rules do not take into account. © 2012 American Institute of Physics

  10. Genetic susceptibility to retinopathy of prematurity: the evidence from clinical and experimental animal studies.

    PubMed

    Holmström, Gerd; van Wijngaarden, Peter; Coster, Douglas J; Williams, Keryn A

    2007-12-01

    Despite advances in management and treatment, retinopathy of prematurity remains a major cause of childhood blindness. Evidence for a genetic basis for susceptibility to retinopathy of prematurity is examined, including the influences of sex, ethnicity, and ocular pigmentation. The role of polymorphisms is explored in the genes for vascular endothelial growth factor and insulin-like growth factor-1, and of mutations in the Norrie disease gene. Insights into the genetic basis of retinopathy of prematurity provided by the animal model of oxygen induced retinopathy are examined. Evidence for a genetic component for susceptibility to retinopathy of prematurity is strong, although the molecular identity of the gene or genes involved remains uncertain.

  11. Reversal of liver cirrhosis: current evidence and expectations.

    PubMed

    Jung, Young Kul; Yim, Hyung Joon

    2017-03-01

    In the past, liver cirrhosis was considered an irreversible phenomenon. However, many experimental data have provided evidence of the reversibility of liver fibrosis. Moreover, multiple clinical studies have also shown regression of fibrosis and reversal of cirrhosis on repeated biopsy samples. As various etiologies are associated with liver fibrosis via integrated signaling pathways, a comprehensive understanding of the pathobiology of hepatic fibrogenesis is critical for improving clinical outcomes. Hepatic stellate cells play a central role in hepatic fibrogenesis upon their activation from a quiescent state. Collagen and other extracellular material components from activated hepatic stellate cells are deposited on, and damage, the liver parenchyma and vascular structures. Hence, inactivation of hepatic stellate cells can lead to enhancement of fibrolytic activity and could be a potential target of antifibrotic therapy. In this regard, continued efforts have been made to develop better treatments for underlying liver diseases and antifibrotic agents in multiple clinical and therapeutic trials; the best results may be expected with the integration of such evidence. In this article, we present the underlying mechanisms of fibrosis, current experimental and clinical evidence of the reversibility of liver fibrosis/cirrhosis, and new agents with therapeutic potential for liver fibrosis.

  12. Reversal of liver cirrhosis: current evidence and expectations

    PubMed Central

    Jung, Young Kul; Yim, Hyung Joon

    2017-01-01

    In the past, liver cirrhosis was considered an irreversible phenomenon. However, many experimental data have provided evidence of the reversibility of liver fibrosis. Moreover, multiple clinical studies have also shown regression of fibrosis and reversal of cirrhosis on repeated biopsy samples. As various etiologies are associated with liver fibrosis via integrated signaling pathways, a comprehensive understanding of the pathobiology of hepatic fibrogenesis is critical for improving clinical outcomes. Hepatic stellate cells play a central role in hepatic fibrogenesis upon their activation from a quiescent state. Collagen and other extracellular material components from activated hepatic stellate cells are deposited on, and damage, the liver parenchyma and vascular structures. Hence, inactivation of hepatic stellate cells can lead to enhancement of fibrolytic activity and could be a potential target of antifibrotic therapy. In this regard, continued efforts have been made to develop better treatments for underlying liver diseases and antifibrotic agents in multiple clinical and therapeutic trials; the best results may be expected with the integration of such evidence. In this article, we present the underlying mechanisms of fibrosis, current experimental and clinical evidence of the reversibility of liver fibrosis/cirrhosis, and new agents with therapeutic potential for liver fibrosis. PMID:28171717

  13. Models and mechanisms of anxiety: evidence from startle studies

    PubMed Central

    Grillon, Christian

    2009-01-01

    Rationale Preclinical data indicates that threat stimuli elicit two classes of defensive behaviors, those that are associated with imminent danger and are characterized by avoidance or fight (fear), and those that are associated with temporally uncertain danger and are characterized by sustained apprehension and hypervigilance (anxiety). Objective To 1) review evidence for a distinction between fear and anxiety in animal and human experimental models using the startle reflex as an operational measure of aversive states, 2) describe experimental models of anxiety, as opposed to fear, in humans, 3) examine the relevance of these models to clinical anxiety. Results The distinction between phasic fear to imminent threat and sustained anxiety to temporally uncertain danger is suggested by psychopharmacological and behavioral evidence from ethological studies and can be traced back to distinct neuroanatomical systems, the amygdala and the bed nucleus of the stria terminalis. Experimental models of anxiety, not fear, are relevant to non-phobic anxiety disorders. Conclusions Progress in our understanding of normal and abnormal anxiety is critically dependent on our ability to model sustained aversive states to temporally uncertain threat. PMID:18058089

  14. Evidence-Based Advances in Reptile Medicine.

    PubMed

    Mitchell, Mark A; Perry, Sean M

    2017-09-01

    Evidence-based medicine allows veterinarians to practice high-quality medicine, because the basis for all decision making is quantitative, objective, and reproducible. Case reports and case series are limited in their scope and application. Cross-sectional studies, likewise, cannot provide answers to specific variable testing with a temporal application. It is essential for the reptile specialty to expand into case-control studies, cohort studies, and experimental/intervention studies. Unfortunately, much of the reptile literature remains limited to descriptive studies. This article reviews current evidence-based topics in reptile medicine and shares how everyone practicing in the field can contribute to improving this specialty. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Chemopreventive properties of 3,3′-diindolylmethane in breast cancer: evidence from experimental and human studies

    PubMed Central

    Ho, Emily; Strom, Meghan B.

    2016-01-01

    Diet is a modifiable factor associated with the risk of several cancers, with convincing evidence showing a link between diet and breast cancer. The role of bioactive compounds of food origin, including those found in cruciferous vegetables, is an active area of research in cancer chemoprevention. This review focuses on 3,3′-diindolylmethane (DIM), the major bioactive indole in crucifers. Research of the cancer-preventive activity of DIM has yielded basic mechanistic, animal, and human trial data. Further, this body of evidence is largely supported by observational studies. Bioactive DIM has demonstrated chemopreventive activity in all stages of breast cancer carcinogenesis. This review describes current evidence related to the metabolism and mechanisms of DIM involved in the prevention of breast cancer. Importantly, this review also focuses on current evidence from human observational and intervention trials that have contributed to a greater understanding of exposure estimates that will inform recommendations for DIM intake. PMID:27261275

  16. Sustainability of Evidence-Based Acute Pain Management Practices for Hospitalized Older Adults.

    PubMed

    Shuman, Clayton J; Xie, Xian-Jin; Herr, Keela A; Titler, Marita G

    2017-11-01

    Little is known regarding sustainability of evidence-based practices (EBPs) following implementation. This article reports sustainability of evidence-based acute pain management practices in hospitalized older adults following testing of a multifaceted Translating Research Into Practice (TRIP) implementation intervention. A cluster randomized trial with follow-up period was conducted in 12 Midwest U.S. hospitals (six experimental, six comparison). Use of evidence-based acute pain management practices and mean pain intensity were analyzed using generalized estimating equations across two time points (following implementation and 18 months later) to determine sustainability of TRIP intervention effects. Summative Index scores and six of seven practices were sustained. Experimental and comparison group differences for mean pain intensity over 72 hours following admission were sustained. Results revealed most evidence-based acute pain management practices were sustained for 18 months following implementation. Further work is needed to identify factors affecting sustainability of EBPs to guide development and testing of sustainability strategies.

  17. A comparative analysis of experimental selection on the stickleback pelvis.

    PubMed

    Miller, S E; Barrueto, M; Schluter, D

    2017-06-01

    Mechanisms of natural selection can be identified using experimental approaches. However, such experiments often yield nonsignificant effects and imprecise estimates of selection due to low power and small sample sizes. Combining results from multiple experimental studies might produce an aggregate estimate of selection that is more revealing than individual studies. For example, bony pelvic armour varies conspicuously among stickleback populations, and predation by vertebrate and insect predators has been hypothesized to be the main driver of this variation. Yet experimental selection studies testing these hypotheses frequently fail to find a significant effect. We experimentally manipulated length of threespine stickleback (Gasterosteus aculeatus) pelvic spines in a mesocosm experiment to test whether prickly sculpin (Cottus asper), an intraguild predator of stickleback, favours longer spines. The probability of survival was greater for stickleback with unclipped pelvic spines, but this effect was noisy and not significant. We used meta-analysis to combine the results of our mesocosm experiment with previously published experimental studies of selection on pelvic armour. We found evidence that fish predation indeed favours increased pelvic armour, with a moderate effect size. The same approach found little evidence that insect predation favours reduced pelvic armour. The causes of reduced pelvic armour in many stickleback populations remain uncertain. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  18. In vivo evidence for a functional role of both tumor necrosis factor (TNF) receptors and transmembrane TNF in experimental hepatitis.

    PubMed

    Küsters, S; Tiegs, G; Alexopoulou, L; Pasparakis, M; Douni, E; Künstle, G; Bluethmann, H; Wendel, A; Pfizenmaier, K; Kollias, G; Grell, M

    1997-11-01

    The significance of tumor necrosis factor receptor 1 (TNFR1) for TNF function in vivo is well documented, whereas the role of TNFR2 so far remains obscure. In a model of concanavalin A (Con A)-induced, CD4+ T cell-dependent experimental hepatitis in mice, in which TNF is a central mediator of apoptotic and necrotic liver damage, we now provide evidence for an essential in vivo function of TNFR2 in this pathophysiological process. We demonstrate that a cooperation of TNFR1 and TNFR2 is required for hepatotoxicity as mice deficient of either receptor were resistant against Con A. A significant role of TNFR2 for Con A-induced hepatitis is also shown by the enhanced sensitivity of transgenic mice overexpressing the human TNFR2. The ligand for cytotoxic signaling via both TNF receptors is the precursor of soluble TNF, i.e. transmembrane TNF. Indeed, transmembrane TNF is sufficient to mediate hepatic damage, as transgenic mice deficient in wild-type soluble TNF but expressing a mutated nonsecretable form of TNF developed inflammatory liver disease.

  19. What Makes an Effective Teacher? Quasi-Experimental Evidence. NBER Working Paper No. 16885

    ERIC Educational Resources Information Center

    Lavy, Victor

    2011-01-01

    This paper measures empirically the relationship between classroom teaching practices and student achievements. Based on primary- and middle-school data from Israel, I find very strong evidence that two important elements of teaching practices cause student achievements to improve. In particular, classroom teaching that emphasizes the instilment…

  20. Experimental and theoretical evidence for bilayer-by-bilayer surface melting of crystalline ice

    PubMed Central

    Sánchez, M. Alejandra; Kling, Tanja; Ishiyama, Tatsuya; van Zadel, Marc-Jan; Mezger, Markus; Jochum, Mara N.; Cyran, Jenée D.; Smit, Wilbert J.; Bakker, Huib J.; Shultz, Mary Jane; Morita, Akihiro; Donadio, Davide; Nagata, Yuki; Bonn, Mischa; Backus, Ellen H. G.

    2017-01-01

    On the surface of water ice, a quasi-liquid layer (QLL) has been extensively reported at temperatures below its bulk melting point at 273 K. Approaching the bulk melting temperature from below, the thickness of the QLL is known to increase. To elucidate the precise temperature variation of the QLL, and its nature, we investigate the surface melting of hexagonal ice by combining noncontact, surface-specific vibrational sum frequency generation (SFG) spectroscopy and spectra calculated from molecular dynamics simulations. Using SFG, we probe the outermost water layers of distinct single crystalline ice faces at different temperatures. For the basal face, a stepwise, sudden weakening of the hydrogen-bonded structure of the outermost water layers occurs at 257 K. The spectral calculations from the molecular dynamics simulations reproduce the experimental findings; this allows us to interpret our experimental findings in terms of a stepwise change from one to two molten bilayers at the transition temperature. PMID:27956637

  1. Building evaluative culture in community services: Caring for evidence.

    PubMed

    Mayne, John

    2017-05-25

    An organization with a strong evaluative culture engages in self-reflection, evidence-based learning and experimentation. It sees evidence as essential for managing well, but building such a culture is challenging. Community service organizations seek to provide effective services for their clients. To build an evaluative culture, they need to acquire basic monitoring and evaluation capabilities, be provided with opportunities for using these capabilities and be adequately motivated to care about evidence as a means to improve services to their clients. Leadership along with a phased in approach are key in bringing about these behaviour changes. Copyright © 2017. Published by Elsevier Ltd.

  2. NEW EXPERIMENTAL EVIDENCES ABOUT THE FORMATION AND CONSUMPTION OF KETOHYDROPEROXIDES

    PubMed Central

    Battin-Leclerc, Frédérique; Herbinet, Olivier; Glaude, Pierre-Alexandre; Fournet, René; Zhou, Zhongyue; Deng, Liulin; Guo, Huijun; Xie, Mingfeng; Qi, Fei

    2013-01-01

    The formation of hydroperoxides postulated in all the kinetic models for the low temperature oxidation of alkanes have been experimentally proved thanks to a new type of apparatus associating a quartz jet-stirred reactor through a molecular-beam sampling system to a reflectron time-of-flight mass spectrometer combined with tunable synchrotron vacuum ultraviolet photoionization. This apparatus has been used to investigate the low-temperature oxidation of n-butane and has allowed demonstrating the formation of different types of alkylhydroperoxides, namely methylhydroperoxide, ethylhydroperoxide and butylhydroperoxide, and of C4 alkylhydroperoxides including a carbonyl function (ketohydroperoxides). In addition, the formation of products deriving from these ketohydroperoxides, such as C4 molecules including either two carbonyl groups or one carbonyl and one alcohol functions, has been observed. Simulations using a detailed kinetic model have been performed to support some of the assumptions made in this work. PMID:23700382

  3. Climate warming drives local extinction: Evidence from observation and experimentation

    PubMed Central

    Panetta, Anne Marie; Stanton, Maureen L.; Harte, John

    2018-01-01

    Despite increasing concern about elevated extinction risk as global temperatures rise, it is difficult to confirm causal links between climate change and extinction. By coupling 25 years of in situ climate manipulation with experimental seed introductions and both historical and current plant surveys, we identify causal, mechanistic links between climate change and the local extinction of a widespread mountain plant (Androsace septentrionalis). Climate warming causes precipitous declines in population size by reducing fecundity and survival across multiple life stages. Climate warming also purges belowground seed banks, limiting the potential for the future recovery of at-risk populations under ameliorated conditions. Bolstered by previous reports of plant community shifts in this experiment and in other habitats, our findings not only support the hypothesis that climate change can drive local extinction but also foreshadow potentially widespread species losses in subalpine meadows as climate warming continues. PMID:29507884

  4. Genetic susceptibility to retinopathy of prematurity: the evidence from clinical and experimental animal studies

    PubMed Central

    Holmström, Gerd; van Wijngaarden, Peter; Coster, Douglas J; Williams, Keryn A

    2007-01-01

    Despite advances in management and treatment, retinopathy of prematurity remains a major cause of childhood blindness. Evidence for a genetic basis for susceptibility to retinopathy of prematurity is examined, including the influences of sex, ethnicity, and ocular pigmentation. The role of polymorphisms is explored in the genes for vascular endothelial growth factor and insulin‐like growth factor‐1, and of mutations in the Norrie disease gene. Insights into the genetic basis of retinopathy of prematurity provided by the animal model of oxygen induced retinopathy are examined. Evidence for a genetic component for susceptibility to retinopathy of prematurity is strong, although the molecular identity of the gene or genes involved remains uncertain. PMID:18024814

  5. Experimental evidence for dynamic friction on rock fractures from frequency-dependent nonlinear hysteresis and harmonic generation

    NASA Astrophysics Data System (ADS)

    Saltiel, Seth; Bonner, Brian P.; Mittal, Tushar; Delbridge, Brent; Ajo-Franklin, Jonathan B.

    2017-07-01

    Frictional properties affect the propagation of high-amplitude seismic waves across rock fractures and faults. Laboratory evidence suggests that these properties can be measured in active seismic surveys, potentially offering a route to characterizing friction in situ. We present experimental results from a subresonance torsional modulus and attenuation apparatus that utilizes micron-scale sinusoidal oscillations to probe the nonlinear stress-strain relation at a range of strain amplitudes and rates. Nonlinear effects are further quantified using harmonic distortion; however, time series data best illuminate underlying physical processes. The low-frequency stress-strain hysteretic loops show stiffening at the sinusoid's static ends, but stiffening is reduced above a threshold frequency. This shape is determined by harmonic generation in the strain; the stress signal has no harmonics, confirming that the fractured sample is the source of the nonlinearity. These qualitative observations suggest the presence of rate-dependent friction and are consistent between fractures in three different rock types. We propose that static friction at the low strain rate part of the cycle, when given sufficient "healing" time at low oscillation frequencies, causes this stiffening cusp shape in the hysteresis loop. While rate-and-state friction is commonly used to represent dynamic friction, it cannot capture static friction or negative slip velocities. So we implement another dynamic friction model, based on the work of Dahl, which describes this process and produces similar results. Since the two models have a similar form, parameterizations of field data could constraint fault model inputs, such as specific location velocity strengthening or weakening properties.

  6. The flaws and human harms of animal experimentation.

    PubMed

    Akhtar, Aysha

    2015-10-01

    Nonhuman animal ("animal") experimentation is typically defended by arguments that it is reliable, that animals provide sufficiently good models of human biology and diseases to yield relevant information, and that, consequently, its use provides major human health benefits. I demonstrate that a growing body of scientific literature critically assessing the validity of animal experimentation generally (and animal modeling specifically) raises important concerns about its reliability and predictive value for human outcomes and for understanding human physiology. The unreliability of animal experimentation across a wide range of areas undermines scientific arguments in favor of the practice. Additionally, I show how animal experimentation often significantly harms humans through misleading safety studies, potential abandonment of effective therapeutics, and direction of resources away from more effective testing methods. The resulting evidence suggests that the collective harms and costs to humans from animal experimentation outweigh potential benefits and that resources would be better invested in developing human-based testing methods.

  7. Can exercise affect the course of inflammatory bowel disease? Experimental and clinical evidence.

    PubMed

    Bilski, Jan; Mazur-Bialy, Agnieszka; Brzozowski, Bartosz; Magierowski, Marcin; Zahradnik-Bilska, Janina; Wójcik, Dagmara; Magierowska, Katarzyna; Kwiecien, Slawomir; Mach, Tomasz; Brzozowski, Tomasz

    2016-08-01

    The inflammatory bowel disease (IBD) consisting of Crohn's disease (CD) and ulcerative colitis (UC) are defined as idiopathic, chronic and relapsing intestinal disorders occurring in genetically predisposed individuals exposed to environmental risk factors such as diet and microbiome changes. Since conventional drug therapy is expensive and not fully efficient, there is a need for alternative remedies that can improve the outcome in patients suffering from IBD. Whether exercise, which has been proposed as adjunct therapy in IBD, can be beneficial in patients with IBD remains an intriguing question. In this review, we provide an overview of the effects of exercise on human IBD and experimental colitis in animal models that mimic human disease, although the information on exercise in human IBD are sparse and poorly understood. Moderate exercise can exert a beneficial ameliorating effect on IBD and improve the healing of experimental animal colitis due to the activity of protective myokines such as irisin released from working skeletal muscles. CD patients with higher levels of exercise were significantly less likely to develop active disease at six months. Moreover, voluntary exercise has been shown to exert a positive effect on IBD patients' mood, weight maintenance and osteoporosis. On the other hand, depending on its intensity and duration, exercise can evoke transient mild systemic inflammation and enhances pro-inflammatory cytokine release, thereby exacerbating the gastrointestinal symptoms. We discuss recent advances in the mechanism of voluntary and strenuous exercise affecting the outcome of IBD in patients and experimental animal models. Copyright © 2016 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  8. The Experimental Evidence in Support of Glycosylation Mechanisms at the SN1-SN2 Interface.

    PubMed

    Adero, Philip Ouma; Amarasekara, Harsha; Wen, Peng; Bohé, Luis; Crich, David

    2018-05-30

    A critical review of the state-of-the-art evidence in support of the mechanisms of glycosylation reactions is provided. Factors affecting the stability of putative oxocarbenium ions as intermediates at the S N 1 end of the mechanistic continuum are first surveyed before the evidence, spectroscopic and indirect, for the existence of such species on the time scale of glycosylation reactions is presented. Current models for diastereoselectivity in nucleophilic attack on oxocarbenium ions are then described. Evidence in support of the intermediacy of activated covalent glycosyl donors is reviewed, before the influences of the structure of the nucleophile, of the solvent, of temperature, and of donor-acceptor hydrogen bonding on the mechanism of glycosylation reactions are surveyed. Studies on the kinetics of glycosylation reactions and the use of kinetic isotope effects for the determination of transition-state structure are presented, before computational models are finally surveyed. The review concludes with a critical appraisal of the state of the art.

  9. The Response of Cerebral Cortex to Haemorrhagic Damage: Experimental Evidence from a Penetrating Injury Model

    PubMed Central

    Purushothuman, Sivaraman; Marotte, Lauren; Stowe, Sally; Johnstone, Daniel M.; Stone, Jonathan

    2013-01-01

    Understanding the response of the brain to haemorrhagic damage is important in haemorrhagic stroke and increasingly in the understanding the cerebral degeneration and dementia that follow head trauma and head-impact sports. In addition, there is growing evidence that haemorrhage from small cerebral vessels is important in the pathogenesis of age-related dementia (Alzheimer’s disease). In a penetration injury model of rat cerebral cortex, we have examined the neuropathology induced by a needlestick injury, with emphasis on features prominent in the ageing and dementing human brain, particularly plaque-like depositions and the expression of related proteins. Needlestick lesions were made in neo- and hippocampal cortex in Sprague Dawley rats aged 3–5 months. Brains were examined after 1–30 d survival, for haemorrhage, for the expression of hyperphosphorylated tau, Aβ, amyloid precursor protein (APP), for gliosis and for neuronal death. Temporal cortex from humans diagnosed with Alzheimer’s disease was examined with the same techniques. Needlestick injury induced long-lasting changes–haem deposition, cell death, plaque-like deposits and glial invasion–along the needle track. Around the track, the lesion induced more transient changes, particularly upregulation of Aβ, APP and hyperphosporylated tau in neurons and astrocytes. Reactions were similar in hippocampus and neocortex, except that neuronal death was more widespread in the hippocampus. In summary, experimental haemorrhagic injury to rat cerebral cortex induced both permanent and transient changes. The more permanent changes reproduced features of human senile plaques, including the formation of extracellular deposits in which haem and Aβ-related proteins co-localised, neuronal loss and gliosis. The transient changes, observed in tissue around the direct lesion, included the upregulation of Aβ, APP and hyperphosphorylated tau, not associated with cell death. The findings support the possibility

  10. Designing a light fabric metamaterial being highly macroscopically tough under directional extension: first experimental evidence

    NASA Astrophysics Data System (ADS)

    dell'Isola, Francesco; Lekszycki, Tomasz; Pawlikowski, Marek; Grygoruk, Roman; Greco, Leopoldo

    2015-12-01

    In this paper, we study a metamaterial constructed with an isotropic material organized following a geometric structure which we call pantographic lattice. This relatively complex fabric was studied using a continuous model (which we call pantographic sheet) by Rivlin and Pipkin and includes two families of flexible fibers connected by internal pivots which are, in the reference configuration, orthogonal. A rectangular specimen having one side three times longer than the other is cut at 45° with respect to the fibers in reference configuration, and it is subjected to large-deformation plane-extension bias tests imposing a relative displacement of shorter sides. The continuum model used, the presented numerical models and the extraordinary advancements of the technology of 3D printing allowed for the design of some first experiments, whose preliminary results are shown and seem to be rather promising. Experimental evidence shows three distinct deformation regimes. In the first regime, the equilibrium total deformation energy depends quadratically on the relative displacement of terminal specimen sides: Applied resultant force depends linearly on relative displacement. In the second regime, the applied force varies nonlinearly on relative displacement, but the behavior remains elastic. In the third regime, damage phenomena start to occur until total failure, but the exerted resultant force continues to be increasing and reaches a value up to several times larger than the maximum shown in the linear regime before failure actually occurs. Moreover, the total energy needed to reach structural failure is larger than the maximum stored elastic energy. Finally, the volume occupied by the material in the fabric is a small fraction of the total volume, so that the ratio weight/resistance to extension is very advantageous. The results seem to require a refinement of the used theoretical and numerical methods to transform the presented concept into a promising technological

  11. Extraction of Pharmacokinetic Evidence of Drug–Drug Interactions from the Literature

    PubMed Central

    Kolchinsky, Artemy; Lourenço, Anália; Wu, Heng-Yi; Li, Lang; Rocha, Luis M.

    2015-01-01

    Drug-drug interaction (DDI) is a major cause of morbidity and mortality and a subject of intense scientific interest. Biomedical literature mining can aid DDI research by extracting evidence for large numbers of potential interactions from published literature and clinical databases. Though DDI is investigated in domains ranging in scale from intracellular biochemistry to human populations, literature mining has not been used to extract specific types of experimental evidence, which are reported differently for distinct experimental goals. We focus on pharmacokinetic evidence for DDI, essential for identifying causal mechanisms of putative interactions and as input for further pharmacological and pharmacoepidemiology investigations. We used manually curated corpora of PubMed abstracts and annotated sentences to evaluate the efficacy of literature mining on two tasks: first, identifying PubMed abstracts containing pharmacokinetic evidence of DDIs; second, extracting sentences containing such evidence from abstracts. We implemented a text mining pipeline and evaluated it using several linear classifiers and a variety of feature transforms. The most important textual features in the abstract and sentence classification tasks were analyzed. We also investigated the performance benefits of using features derived from PubMed metadata fields, various publicly available named entity recognizers, and pharmacokinetic dictionaries. Several classifiers performed very well in distinguishing relevant and irrelevant abstracts (reaching F1≈0.93, MCC≈0.74, iAUC≈0.99) and sentences (F1≈0.76, MCC≈0.65, iAUC≈0.83). We found that word bigram features were important for achieving optimal classifier performance and that features derived from Medical Subject Headings (MeSH) terms significantly improved abstract classification. We also found that some drug-related named entity recognition tools and dictionaries led to slight but significant improvements, especially in

  12. Evidence for Tempo-Specific Timing in Music Using a Web-Based Experimental Setup

    ERIC Educational Resources Information Center

    Honing, Henkjan

    2006-01-01

    Perceptual invariance has been studied and found in several domains of cognition, including those of speech, motor behavior, and object motion. It has also been the topic of several studies in music perception. However, the existing perceptual studies present rather inconclusive evidence with regard to the perceptual invariance of expressive…

  13. Experimental Evidence for Reduced Rodent Diversity Causing Increased Hantavirus Prevalence

    PubMed Central

    Suzán, Gerardo; Marcé, Erika; Giermakowski, J. Tomasz; Mills, James N.; Ceballos, Gerardo; Ostfeld, Richard S.; Armién, Blas; Pascale, Juan M.; Yates, Terry L.

    2009-01-01

    Emerging and re-emerging infectious diseases have become a major global environmental problem with important public health, economic, and political consequences. The etiologic agents of most emerging infectious diseases are zoonotic, and anthropogenic environmental changes that affect wildlife communities are increasingly implicated in disease emergence and spread. Although increased disease incidence has been correlated with biodiversity loss for several zoonoses, experimental tests in these systems are lacking. We manipulated small-mammal biodiversity by removing non-reservoir species in replicated field plots in Panama, where zoonotic hantaviruses are endemic. Both infection prevalence of hantaviruses in wild reservoir (rodent) populations and reservoir population density increased where small-mammal species diversity was reduced. Regardless of other variables that affect the prevalence of directly transmitted infections in natural communities, high biodiversity is important in reducing transmission of zoonotic pathogens among wildlife hosts. Our results have wide applications in both conservation biology and infectious disease management. PMID:19421313

  14. Quasi-experimental study designs series-paper 8: identifying quasi-experimental studies to inform systematic reviews.

    PubMed

    Glanville, Julie; Eyers, John; Jones, Andrew M; Shemilt, Ian; Wang, Grace; Johansen, Marit; Fiander, Michelle; Rothstein, Hannah

    2017-09-01

    This article reviews the available evidence and guidance on methods to identify reports of quasi-experimental (QE) studies to inform systematic reviews of health care, public health, international development, education, crime and justice, and social welfare. Research, guidance, and examples of search strategies were identified by searching a range of databases, key guidance documents, selected reviews, conference proceedings, and personal communication. Current practice and research evidence were summarized. Four thousand nine hundred twenty-four records were retrieved by database searches, and additional documents were obtained by other searches. QE studies are challenging to identify efficiently because they have no standardized nomenclature and may be indexed in various ways. Reliable search filters are not available. There is a lack of specific resources devoted to collecting QE studies and little evidence on where best to search. Searches to identify QE studies should search a range of resources and, until indexing improves, use strategies that focus on the topic rather than the study design. Better definitions, better indexing in databases, prospective registers, and reporting guidance are required to improve the retrieval of QE studies and promote systematic reviews of what works based on the evidence from such studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Understanding Counterfactuality: A Review of Experimental Evidence for the Dual Meaning of Counterfactuals

    PubMed Central

    Nieuwland, Mante S.

    2016-01-01

    Abstract Cognitive and linguistic theories of counterfactual language comprehension assume that counterfactuals convey a dual meaning. Subjunctive‐counterfactual conditionals (e.g., ‘If Tom had studied hard, he would have passed the test’) express a supposition while implying the factual state of affairs (Tom has not studied hard and failed). The question of how counterfactual dual meaning plays out during language processing is currently gaining interest in psycholinguistics. Whereas numerous studies using offline measures of language processing consistently support counterfactual dual meaning, evidence coming from online studies is less conclusive. Here, we review the available studies that examine online counterfactual language comprehension through behavioural measurement (self‐paced reading times, eye‐tracking) and neuroimaging (electroencephalography, functional magnetic resonance imaging). While we argue that these studies do not offer direct evidence for the online computation of counterfactual dual meaning, they provide valuable information about the way counterfactual meaning unfolds in time and influences successive information processing. Further advances in research on counterfactual comprehension require more specific predictions about how counterfactual dual meaning impacts incremental sentence processing. PMID:27512408

  16. Evidence For Multiple Cell Death Pathways during Development of Experimental Cytomegalovirus Retinitis in Mice with Retrovirus-Induced Immunosuppression: Apoptosis, Necroptosis, and Pyroptosis

    PubMed Central

    Chien, Hsin

    2012-01-01

    AIDS-related human cytomegalovirus (HCMV) retinitis remains a major ophthalmologic problem worldwide. Although this sight-threatening disease is well characterized clinically, many pathogenic issues remain unresolved, among them a basic understanding of the relative roles of cell death pathways during development of retinal tissue destruction. Using an established model of experimental murine cytomegalovirus (MCMV) retinitis in mice with retrovirus-induced immunosuppression (MAIDS), we initially investigated MCMV-infected eyes for evidence of apoptosis-associated molecules in mice with MAIDS of 4 weeks' (MAIDS-4) and 10 weeks' (MAIDS-10) duration, which were resistant and susceptible to retinal disease, respectively, but which harbored equivalent amounts of infectious MCMV. Whereas MCMV-infected eyes of MAIDS-4 mice showed little evidence of apoptosis-associated molecules, MCMV-infected eyes of MAIDS-10 mice showed significant amounts of tumor necrosis factor alpha (TNF-α), TNF receptors 1 and 2, active caspase 8, active caspase 3, TNF-related apoptosis-inducing ligand (TRAIL), TRAIL-R(DR5), Fas, and Fas ligand mRNAs and/or proteins, all detected at peak amounts prior to development of most severe retinal disease. Immunohistochemical staining showed macrophages, granulocytes (neutrophils), Müller cells, and microglial cells as TNF-α sources. Remarkably, quantification of apoptosis by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay suggested that apoptosis contributed minimally to retinal disease in MCMV-infected eyes of MAIDS-10 mice. Subsequent studies demonstrated that MCMV-infected eyes of MAIDS-10 mice, but not MAIDS-4 mice, showed evidence of significant increases in molecules associated with two additional cell death pathways, necroptosis (receptor-interacting protein 1 [RIP1] and RIP3 mRNAs) and pyroptosis (caspase 1, interleukin 1β [IL-1β], and IL-18 mRNAs). We conclude that apoptosis, necroptosis, and

  17. On the psychology of cooperation in humans and other primates: combining the natural history and experimental evidence of prosociality

    PubMed Central

    Jaeggi, Adrian V.; Burkart, Judith M.; Van Schaik, Carel P.

    2010-01-01

    In any given species, cooperation involves prosocial acts that usually return a fitness benefit to the actor. These acts are produced by a set of psychological rules, which will be similar in related species if they have a similar natural history of cooperation. Prosocial acts can be (i) reactive, i.e. in response to specific stimuli, or (ii) proactive, i.e. occur in the absence of such stimuli. We propose that reactive prosocial acts reflect sensitivity to (i) signals or signs of need and (ii) the presence and size of an audience, as modified by (iii) social distance to the partner or partners. We examine the evidence for these elements in humans and other animals, especially non-human primates, based on the natural history of cooperation, quantified in the context of food sharing, and various experimental paradigms. The comparison suggests that humans share with their closest living relatives reactive responses to signals of need, but differ in sensitivity to signs of need and cues of being watched, as well as in the presence of proactive prosociality. We discuss ultimate explanations for these derived features, in particular the adoption of cooperative breeding as well as concern for reputation and costly signalling during human evolution. PMID:20679115

  18. Experimental evidence for the evolution of indirect genetic effects: changes in the interaction effect coefficient, psi (Psi), due to sexual selection.

    PubMed

    Chenoweth, Stephen F; Rundle, Howard D; Blows, Mark W

    2010-06-01

    Indirect genetics effects (IGEs)--when the genotype of one individual affects the phenotypic expression of a trait in another--may alter evolutionary trajectories beyond that predicted by standard quantitative genetic theory as a consequence of genotypic evolution of the social environment. For IGEs to occur, the trait of interest must respond to one or more indicator traits in interacting conspecifics. In quantitative genetic models of IGEs, these responses (reaction norms) are termed interaction effect coefficients and are represented by the parameter psi (Psi). The extent to which Psi exhibits genetic variation within a population, and may therefore itself evolve, is unknown. Using an experimental evolution approach, we provide evidence for a genetic basis to the phenotypic response caused by IGEs on sexual display traits in Drosophila serrata. We show that evolution of the response is affected by sexual but not natural selection when flies adapt to a novel environment. Our results indicate a further mechanism by which IGEs can alter evolutionary trajectories--the evolution of interaction effects themselves.

  19. Evidence for viable, non-clonal but fatherless Boa constrictors.

    PubMed

    Booth, Warren; Johnson, Daniel H; Moore, Sharon; Schal, Coby; Vargo, Edward L

    2011-04-23

    Parthenogenesis in vertebrates is considered an evolutionary novelty. In snakes, all of which exhibit genetic sex determination with ZZ : ZW sex chromosomes, this rare form of asexual reproduction has failed to yield viable female WW offspring. Only through complex experimental manipulations have WW females been produced, and only in fish and amphibians. Through microsatellite DNA fingerprinting, we provide the first evidence of facultative parthenogenesis in a Boa constrictor, identifying multiple, viable, non-experimentally induced females for the first time in any vertebrate lineage. Although the elevated homozygosity of the offspring in relation to the mother suggests that the mechanism responsible may be terminal fusion automixis, no males were produced, potentially indicating maternal sex chromosome hemizygosity (WO). These findings provide the first evidence of parthenogenesis in the family Boidae (Boas), and suggest that WW females may be more common within basal reptilian lineages than previously assumed.

  20. Evidence for viable, non-clonal but fatherless Boa constrictors

    PubMed Central

    Booth, Warren; Johnson, Daniel H.; Moore, Sharon; Schal, Coby; Vargo, Edward L.

    2011-01-01

    Parthenogenesis in vertebrates is considered an evolutionary novelty. In snakes, all of which exhibit genetic sex determination with ZZ : ZW sex chromosomes, this rare form of asexual reproduction has failed to yield viable female WW offspring. Only through complex experimental manipulations have WW females been produced, and only in fish and amphibians. Through microsatellite DNA fingerprinting, we provide the first evidence of facultative parthenogenesis in a Boa constrictor, identifying multiple, viable, non-experimentally induced females for the first time in any vertebrate lineage. Although the elevated homozygosity of the offspring in relation to the mother suggests that the mechanism responsible may be terminal fusion automixis, no males were produced, potentially indicating maternal sex chromosome hemizygosity (WO). These findings provide the first evidence of parthenogenesis in the family Boidae (Boas), and suggest that WW females may be more common within basal reptilian lineages than previously assumed. PMID:21047849

  1. Evidence-Based Kernels: Fundamental Units of Behavioral Influence

    ERIC Educational Resources Information Center

    Embry, Dennis D.; Biglan, Anthony

    2008-01-01

    This paper describes evidence-based kernels, fundamental units of behavioral influence that appear to underlie effective prevention and treatment for children, adults, and families. A kernel is a behavior-influence procedure shown through experimental analysis to affect a specific behavior and that is indivisible in the sense that removing any of…

  2. Teacher Opinions on Performance Pay: Evidence from India

    ERIC Educational Resources Information Center

    Muralidharan, Karthik; Sundararaman, Venkatesh

    2011-01-01

    The practical viability of performance-based pay programs for teachers depends critically on the extent of support the idea will receive from teachers. We present evidence on teacher opinions with regard to performance-based pay from teacher interviews conducted in the context of an experimental evaluation of a program that provided…

  3. A Direct Experimental Evidence For the New Thermodynamic Boundary in the Supercritical State: Implications for Earth and Planetary Sciences.

    NASA Astrophysics Data System (ADS)

    Bolmatov, D.

    2015-12-01

    While scientists have a good theoretical understanding of the heat capacity of both solids and gases, a general theory of the heat capacity of liquids has always remained elusive. Apart from being an awkward hole in our knowledge, heat capacity - the amount of heat needed to change a substance's temperature by a certain amount - is a relevant quantity that it would be nice to be able to predict. I will introduce a phonon-based approach to liquids and supercritical fluids to describe its thermodynamics in terms of sound propagation. I will show that the internal liquid energy has a transverse sound propagation gaps and explain their evolution with temperature variations on the P-T diagram. I will explain how this theoretical framework covers the Debye theory of solids, the phonon theory of liquids, and thermodynamic limits such as the Delong-Petit and the ideal gas thermodynamic limits. As a results, the experimental evidence for the new thermodynamic boundary in the supercritical state (the Frenkel line) on the P-T phase diagram will be demonstrated. Then, I will report on inelastic X-ray scattering experiments combined with the molecular dynamics simulations on deeply supercritical Ar. The presented results unveil the mechanism and regimes of sound propagation in the liquid matter and provide compelling evidence for the adiabatic-to-isothermal longitudinal sound propagation transition. As a result, a universal link will be demonstrated between the positive sound dispersion (PSD) phenomenon and the origin of transverse sound propagation revealing the viscous-to-elastic crossover in compressed liquids. Both can be considered as a universal fingerprint of the dynamic response of a liquid. They can be used then for a signal detection and analysis of a dynamic response in deep water and other fluids which is relevant for describing the thermodynamics of gas giants. The consequences of this finding will be discussed, including a physically justified way to demarcate the

  4. Dysphagia as a risk factor for mortality in Niemann-Pick disease type C: systematic literature review and evidence from studies with miglustat

    PubMed Central

    2012-01-01

    Niemann-Pick disease type C (NP-C) is a rare neurovisceral disease characterised by progressive neurological deterioration and premature death, and has an estimated birth incidence of 1:120,000. Mutations in the NPC1 gene (in 95% of cases) and the NPC2 gene (in approximately 4% of cases) give rise to impaired intracellular lipid metabolism in a number of tissues, including the brain. Typical neurological manifestations include vertical supranuclear gaze palsy, saccadic eye movement abnormalities, cerebellar ataxia, dystonia, dysmetria, dysphagia and dysarthria. Oropharyngeal dysphagia can be particularly problematic as it can often lead to food or fluid aspiration and subsequent pneumonia. Epidemiological data suggest that bronchopneumonia subsequent to food or fluid aspiration is a major cause of mortality in NP-C and other neurodegenerative disorders. These findings indicate that a therapy capable of improving or stabilising swallowing function might reduce the risk of aspiration pneumonia, and could have a positive impact on patient survival. Miglustat, currently the only approved disease-specific therapy for NP-C in children and adults, has been shown to stabilise key neurological manifestations in NP-C, including dysphagia. In this article we present findings from a systematic literature review of published data on bronchopneumonia/aspiration pneumonia as a cause of death, and on the occurrence of dysphagia in NP-C and other neurodegenerative diseases. We then examine the potential links between dysphagia, aspiration, pneumonia and mortality with a view to assessing the possible effect of miglustat on patient lifespan. PMID:23039766

  5. Porphyromonas gingivalis Peptidylarginine Deiminase, a Key Contributor in the Pathogenesis of Experimental Periodontal Disease and Experimental Arthritis

    PubMed Central

    Gully, Neville; Bright, Richard; Marino, Victor; Marchant, Ceilidh; Cantley, Melissa; Haynes, David; Butler, Catherine; Dashper, Stuart; Reynolds, Eric; Bartold, Mark

    2014-01-01

    Objectives To investigate the suggested role of Porphyromonas gingivalis peptidylarginine deiminase (PAD) in the relationship between the aetiology of periodontal disease and experimentally induced arthritis and the possible association between these two conditions. Methods A genetically modified PAD-deficient strain of P. gingivalis W50 was produced. The effect of this strain, compared to the wild type, in an established murine model for experimental periodontitis and experimental arthritis was assessed. Experimental periodontitis was induced following oral inoculation with the PAD-deficient and wild type strains of P. gingivalis. Experimental arthritis was induced via the collagen antibody induction process and was monitored by assessment of paw swelling and micro-CT analysis of the radio-carpal joints. Experimental periodontitis was monitored by micro CT scans of the mandible and histological assessment of the periodontal tissues around the mandibular molars. Serum levels of anti-citrullinated protein antibodies (ACPA) and P. gingivalis were assessed by ELISA. Results The development of experimental periodontitis was significantly reduced in the presence of the PAD-deficient P. gingivalis strain. When experimental arthritis was induced in the presence of the PAD-deficient strain there was less paw swelling, less erosive bone damage to the joints and reduced serum ACPA levels when compared to the wild type P. gingivalis inoculated group. Conclusion This study has demonstrated that a PAD-deficient strain of P. gingivalis was associated with significantly reduced periodontal inflammation. In addition the extent of experimental arthritis was significantly reduced in animals exposed to prior induction of periodontal disease through oral inoculation of the PAD-deficient strain versus the wild type. This adds further evidence to the potential role for P. gingivalis and its PAD in the pathogenesis of periodontitis and exacerbation of arthritis. Further studies are now

  6. Trichloroethylene: Mechanistic, epidemiologic and other supporting evidence of carcinogenic hazard.

    PubMed

    Rusyn, Ivan; Chiu, Weihsueh A; Lash, Lawrence H; Kromhout, Hans; Hansen, Johnni; Guyton, Kathryn Z

    2014-01-01

    The chlorinated solvent trichloroethylene (TCE) is a ubiquitous environmental pollutant. The carcinogenic hazard of TCE was the subject of a 2012 evaluation by a Working Group of the International Agency for Research on Cancer (IARC). Information on exposures, relevant data from epidemiologic studies, bioassays in experimental animals, and toxicity and mechanism of action studies was used to conclude that TCE is carcinogenic to humans (Group 1). This article summarizes the key evidence forming the scientific bases for the IARC classification. Exposure to TCE from environmental sources (including hazardous waste sites and contaminated water) is common throughout the world. While workplace use of TCE has been declining, occupational exposures remain of concern, especially in developing countries. The strongest human evidence is from studies of occupational TCE exposure and kidney cancer. Positive, although less consistent, associations were reported for liver cancer and non-Hodgkin lymphoma. TCE is carcinogenic at multiple sites in multiple species and strains of experimental animals. The mechanistic evidence includes extensive data on the toxicokinetics and genotoxicity of TCE and its metabolites. Together, available evidence provided a cohesive database supporting the human cancer hazard of TCE, particularly in the kidney. For other target sites of carcinogenicity, mechanistic and other data were found to be more limited. Important sources of susceptibility to TCE toxicity and carcinogenicity were also reviewed by the Working Group. In all, consideration of the multiple evidence streams presented herein informed the IARC conclusions regarding the carcinogenicity of TCE. © 2013.

  7. Trichloroethylene: Mechanistic, Epidemiologic and Other Supporting Evidence of Carcinogenic Hazard

    PubMed Central

    Rusyn, Ivan; Chiu, Weihsueh A.; Lash, Lawrence H.; Kromhout, Hans; Hansen, Johnni; Guyton, Kathryn Z.

    2013-01-01

    The chlorinated solvent trichloroethylene (TCE) is a ubiquitous environmental pollutant. The carcinogenic hazard of TCE was the subject of a 2012 evaluation by a Working Group of the International Agency for Research on Cancer (IARC). Information on exposures, relevant data from epidemiologic studies, bioassays in experimental animals, and toxicity and mechanism of action studies was used to conclude that TCE is carcinogenic to humans (Group 1). This article summarizes the key evidence forming the scientific bases for the IARC classification. Exposure to TCE from environmental sources (including from hazardous waste sites and contaminated water) is common throughout the world. While workplace use of TCE has been declining, occupational exposures remain of concern, especially in developing countries. Strongest human evidence is from studies of occupational TCE exposure and kidney cancer. Positive, although less consistent, associations were reported for liver cancer and non-Hodgkin's lymphoma. TCE is carcinogenic at multiple sites in multiple species and strains of experimental animals. The mechanistic evidence includes extensive data on the toxicokinetics and genotoxicity of TCE and its metabolites. Together, available evidence provided a cohesive database supporting the human cancer hazard of TCE, particularly in the kidney. For other target sites of carcinogenicity, mechanistic and other data were found to be more limited. Important sources of susceptibility to TCE toxicity and carcinogenicity were also reviewed by the Working Group. In all, consideration of the multiple evidence streams presented herein informed the IARC conclusions regarding the carcinogenicity of TCE. PMID:23973663

  8. An Application of Brief Experimental Analysis with Early Writing

    ERIC Educational Resources Information Center

    Parker, David C.; Dickey, Bradley N.; Burns, Matthew K.; McMaster, Kristen L.

    2012-01-01

    Students' poor performance on national assessments of writing suggests that educators need effective approaches to assess and intervene with writing problems. Brief experimental analysis (BEA) has supporting evidence for identifying interventions in reading, but little research has investigated BEA with writing. Early writing is an especially…

  9. Evidence, temperature, and the laws of thermodynamics.

    PubMed

    Vieland, Veronica J

    2014-01-01

    A primary purpose of statistical analysis in genetics is the measurement of the strength of evidence for or against hypotheses. As with any type of measurement, a properly calibrated measurement scale is necessary if we want to be able to meaningfully compare degrees of evidence across genetic data sets, across different types of genetic studies and/or across distinct experimental modalities. In previous papers in this journal and elsewhere, my colleagues and I have argued that geneticists ought to care about the scale on which statistical evidence is measured, and we have proposed the Kelvin temperature scale as a template for a context-independent measurement scale for statistical evidence. Moreover, we have claimed that, mathematically speaking, evidence and temperature may be one and the same thing. On first blush, this might seem absurd. Temperature is a property of systems following certain laws of nature (in particular, the 1st and 2nd Law of Thermodynamics) involving very physical quantities (e.g., energy) and processes (e.g., mechanical work). But what do the laws of thermodynamics have to do with statistical systems? Here I address that question. © 2014 S. Karger AG, Basel.

  10. Adaptation and adaptation transfer characteristics of five different saccade types in the monkey

    PubMed Central

    Fuchs, Albert F.; Soetedjo, Robijanto

    2015-01-01

    Shifts in the direction of gaze are accomplished by different kinds of saccades, which are elicited under different circumstances. Saccade types include targeting saccades to simple jumping targets, delayed saccades to visible targets after a waiting period, memory-guided (MG) saccades to remembered target locations, scanning saccades to stationary target arrays, and express saccades after very short latencies. Studies of human cases and neurophysiological experiments in monkeys suggest that separate pathways, which converge on a common locus that provides the motor command, generate these different types of saccade. When behavioral manipulations in humans cause targeting saccades to have persistent dysmetrias as might occur naturally from growth, aging, and injury, they gradually adapt to reduce the dysmetria. Although results differ slightly between laboratories, this adaptation generalizes or transfers to all the other saccade types mentioned above. Also, when one of the other types of saccade undergoes adaptation, it often transfers to another saccade type. Similar adaptation and transfer experiments, which allow inferences to be drawn about the site(s) of adaptation for different saccade types, have yet to be done in monkeys. Here we show that simian targeting and MG saccades adapt more than express, scanning, and delayed saccades. Adaptation of targeting saccades transfers to all the other saccade types. However, the adaptation of MG saccades transfers only to delayed saccades. These data suggest that adaptation of simian targeting saccades occurs on the pathway common to all saccade types. In contrast, only the delayed saccade command passes through the adaptation site of the MG saccade. PMID:25855693

  11. Experimental evidence of a helical, supercritical instability in pipe flow of shear thinning fluids

    NASA Astrophysics Data System (ADS)

    Picaut, L.; Ronsin, O.; Caroli, C.; Baumberger, T.

    2017-08-01

    We study experimentally the flow stability of entangled polymer solutions extruded through glass capillaries. We show that the pipe flow becomes linearly unstable beyond a critical value (Wic≃5 ) of the Weissenberg number, via a supercritical bifurcation which results in a helical distortion of the extrudate. We find that the amplitude of the undulation vanishes as the aspect ratio L /R of the capillary tends to zero, and saturates for large L /R , indicating that the instability affects the whole pipe flow, rather than the contraction or exit regions. These results, when compared to previous theoretical and experimental works, lead us to argue that the nature of the instability is controlled by the level of shear thinning of the fluids. In addition, we provide strong hints that the nonlinear development of the instabiilty is mitigated, in our system, by the gradual emergence of gross wall slip.

  12. The research evidence published in high impact nursing journals between 2000 and 2006: a quantitative content analysis.

    PubMed

    Mantzoukas, Stefanos

    2009-04-01

    Evidence-based practice has become an imperative for efficient, effective and safe practice. Furthermore, evidences emerging from published research are considered as valid knowledge sources to guiding practice. The aim of this paper is to review all research articles published in the top 10 general nursing journals for the years 2000-2006 to identify the methodologies used, the types of evidence these studies produced and the issues upon which they endeavored. Quantitative content analysis was implemented to study all published research papers of the top 10 general nursing journals for the years 2000-2006. The top 10 general nursing journals were included in the study. The abstracts of all research articles were analysed with regards the methodologies of enquiry, the types of evidence produced and the issues of study they endeavored upon. Percentages were developed as to enable conclusions to be drawn. The results for the category methodologies used were 7% experimental, 6% quasi-experimental, 39% non-experimental, 2% ethnographical studies, 7% phenomenological, 4% grounded theory, 1% action research, 1% case study, 15% unspecified, 5.5% other, 0.5% meta-synthesis, 2% meta-analysis, 5% literature reviews and 3% secondary analysis. For the category types of evidence were 4% hypothesis/theory testing, 11% evaluative, 5% comparative, 2% correlational, 46% descriptive, 5% interpretative and 27% exploratory. For the category issues of study were 45% practice/clinical, 8% educational, 11% professional, 3% spiritual/ethical/metaphysical, 26% health promotion and 7% managerial/policy. Published studies can provide adequate evidences for practice if nursing journals conceptualise evidence emerging from non-experimental and qualitative studies as relevant types of evidences for practice and develop appropriate mechanisms for assessing their validity. Also, nursing journals need to increase and encourage the publication of studies that implement RCT methodology, systematic

  13. Experimental evidence for chick discrimination without recognition in a brood parasite host.

    PubMed

    Grim, Tomás

    2007-02-07

    Recognition is considered a critical basis for discriminatory behaviours in animals. Theoretically, recognition and discrimination of parasitic chicks are not predicted to evolve in hosts of brood parasitic birds that evict nest-mates. Yet, an earlier study showed that host reed warblers (Acrocephalus scirpaceus) of an evicting parasite, the common cuckoo (Cuculus canorus), can avoid the costs of prolonged care for unrelated young by deserting the cuckoo chick before it fledges. Desertion was not based on specific recognition of the parasite because hosts accept any chick cross-fostered into their nests. Thus, the mechanism of this adaptive host response remains enigmatic. Here, I show experimentally that the cue triggering this 'discrimination without recognition' behaviour is the duration of parental care. Neither the intensity of brood care nor the presence of a single-chick in the nest could explain desertions. Hosts responded similarly to foreign chicks, whether heterospecific or experimental conspecifics. The proposed mechanism of discrimination strikingly differs from those found in other parasite-host systems because hosts do not need an internal recognition template of the parasite's appearance to effectively discriminate. Thus, host defences against parasitic chicks may be based upon mechanisms qualitatively different from those operating against parasitic eggs. I also demonstrate that this discriminatory mechanism is non-costly in terms of recognition errors. Comparative data strongly suggest that parasites cannot counter-evolve any adaptation to mitigate effects of this host defence. These findings have crucial implications for the process and end-result of host-parasite arms races and our understanding of the cognitive basis of discriminatory mechanisms in general.

  14. Visuospatial Orientational Shifts: Evidence for Three Independent Mechanisms.

    ERIC Educational Resources Information Center

    Noonan, Michael; Axelrod, Seymour

    While it is often assumed that a single mechanism underlies varied experimental evidences of selectivity, Berlyne (1969) suggested that attention-like selectivity may take place in a number of quite separate neural systems. This study examined the issue of visuospatial attention by investigating covert orientation or "looking out of the corner of…

  15. Disruptive changes of cerebellar functional connectivity with the default mode network in schizophrenia.

    PubMed

    Wang, Lubin; Zou, Feng; Shao, Yongcong; Ye, Enmao; Jin, Xiao; Tan, Shuwen; Hu, Dewen; Yang, Zheng

    2014-12-01

    The default mode network (DMN) plays an important role in the physiopathology of schizophrenia. Previous studies have suggested that the cerebellum participates in higher-order cognitive networks such as the DMN. However, the specific contribution of the cerebellum to the DMN abnormalities in schizophrenia has yet to be established. In this study, we investigated cerebellar functional connectivity differences between 60 patients with schizophrenia and 60 healthy controls from a public resting-state fMRI database. Seed-based correlation analysis was performed by using seeds from the left Crus I, right Crus I and Lobule IX, which have previously been identified as being involved in the DMN. Our results revealed that, compared with the healthy controls, the patients showed significantly reduced cerebellar functional connectivity with the thalamus and several frontal regions including the middle frontal gyrus, anterior cingulate cortex, and supplementary motor area. Moreover, the positive correlations between the strength of frontocerebellar and thalamocerebellar functional connectivity observed in the healthy subjects were diminished in the patients. Our findings implicate disruptive changes of the fronto-thalamo-cerebellar circuit in schizophrenia, which may provide further evidence for the "cognitive dysmetria" concept of schizophrenia. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. The smell of "anxiety": Behavioral modulation by experimental anosmia in zebrafish.

    PubMed

    Abreu, Murilo S; Giacomini, Ana C V V; Kalueff, Allan V; Barcellos, Leonardo J G

    2016-04-01

    Olfaction is strongly involved in the regulation of fish behavior, including reproductive, defensive, social and migration behaviors. In fish, anosmia (the lack of olfaction) can be induced experimentally, impairing their ability to respond to various olfactory stimuli. Here, we examine the effects of experimental lidocaine-induced anosmia on anxiety-like behavior and whole-body cortisol levels in adult zebrafish (Danio rerio). We show that experimentally-induced anosmia reduces anxiolytic-like behavioral effects of fluoxetine and seems to interact with anxiogenic effect of stress also paralleling cortisol responses in zebrafish. These findings provide first experimental evidence that temporary anosmia modulates anxiety-like behaviors and physiology in adult zebrafish. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Experimental challenge of pregnant cattle with the putative abortifacient Waddlia chondrophila.

    PubMed

    Wheelhouse, Nicholas; Flockhart, Allen; Aitchison, Kevin; Livingstone, Morag; Finlayson, Jeanie; Flachon, Virginie; Sellal, Eric; Dagleish, Mark P; Longbottom, David

    2016-11-14

    Waddlia chondrophila is a Gram-negative intracellular bacterial organism that is related to classical chlamydial species and has been implicated as a cause of abortion in cattle. Despite an increasing number of observational studies linking W. chondrophila infection to cattle abortion, little direct experimental evidence exists. Given this paucity of direct evidence the current study was carried out to investigate whether experimental challenge of pregnant cattle with W. chondrophila would result in infection and abortion. Nine pregnant Friesian-Holstein heifers received 2 × 10 8 inclusion forming units (IFU) W. chondrophila intravenously on day 105-110 of pregnancy, while four negative-control animals underwent mock challenge. Only one of the challenged animals showed pathogen-associated lesions, with the organism being detected in the diseased placenta. Importantly, the organism was re-isolated and its identity confirmed by whole genome sequencing, confirming Koch's third and fourth postulates. However, while infection of the placenta was observed, the experimental challenge in this study did not confirm the abortifacient potential of the organism.

  18. Range expansion promotes cooperation in an experimental microbial metapopulation

    PubMed Central

    Datta, Manoshi Sen; Korolev, Kirill S.; Cvijovic, Ivana; Dudley, Carmel; Gore, Jeff

    2013-01-01

    Natural populations throughout the tree of life undergo range expansions in response to changes in the environment. Recent theoretical work suggests that range expansions can have a strong effect on evolution, even leading to the fixation of deleterious alleles that would normally be outcompeted in the absence of migration. However, little is known about how range expansions might influence alleles under frequency- or density-dependent selection. Moreover, there is very little experimental evidence to complement existing theory, since expanding populations are difficult to study in the natural environment. In this study, we have used a yeast experimental system to explore the effect of range expansions on the maintenance of cooperative behaviors, which commonly display frequency- and density-dependent selection and are widespread in nature. We found that range expansions favor the maintenance of cooperation in two ways: (i) through the enrichment of cooperators at the front of the expanding population and (ii) by allowing cooperators to “outrun” an invading wave of defectors. In this system, cooperation is enhanced through the coupling of population ecology and evolutionary dynamics in expanding populations, thus providing experimental evidence for a unique mechanism through which cooperative behaviors could be maintained in nature. PMID:23569263

  19. Vanadium supersaturated silicon system: a theoretical and experimental approach

    NASA Astrophysics Data System (ADS)

    Garcia-Hemme, Eric; García, Gregorio; Palacios, Pablo; Montero, Daniel; García-Hernansanz, Rodrigo; Gonzalez-Diaz, Germán; Wahnon, Perla

    2017-12-01

    The effect of high dose vanadium ion implantation and pulsed laser annealing on the crystal structure and sub-bandgap optical absorption features of V-supersaturated silicon samples has been studied through the combination of experimental and theoretical approaches. Interest in V-supersaturated Si focusses on its potential as a material having a new band within the Si bandgap. Rutherford backscattering spectrometry measurements and formation energies computed through quantum calculations provide evidence that V atoms are mainly located at interstitial positions. The response of sub-bandgap spectral photoconductance is extended far into the infrared region of the spectrum. Theoretical simulations (based on density functional theory and many-body perturbation in GW approximation) bring to light that, in addition to V atoms at interstitial positions, Si defects should also be taken into account in explaining the experimental profile of the spectral photoconductance. The combination of experimental and theoretical methods provides evidence that the improved spectral photoconductance up to 6.2 µm (0.2 eV) is due to new sub-bandgap transitions, for which the new band due to V atoms within the Si bandgap plays an essential role. This enables the use of V-supersaturated silicon in the third generation of photovoltaic devices.

  20. Evidence Combination From an Evolutionary Game Theory Perspective

    PubMed Central

    Deng, Xinyang; Han, Deqiang; Dezert, Jean; Deng, Yong; Shyr, Yu

    2017-01-01

    Dempster-Shafer evidence theory is a primary methodology for multi-source information fusion because it is good at dealing with uncertain information. This theory provides a Dempster’s rule of combination to synthesize multiple evidences from various information sources. However, in some cases, counter-intuitive results may be obtained based on that combination rule. Numerous new or improved methods have been proposed to suppress these counter-intuitive results based on perspectives, such as minimizing the information loss or deviation. Inspired by evolutionary game theory, this paper considers a biological and evolutionary perspective to study the combination of evidences. An evolutionary combination rule (ECR) is proposed to help find the most biologically supported proposition in a multi-evidence system. Within the proposed ECR, we develop a Jaccard matrix game (JMG) to formalize the interaction between propositions in evidences, and utilize the replicator dynamics to mimick the evolution of propositions. Experimental results show that the proposed ECR can effectively suppress the counter-intuitive behaviors appeared in typical paradoxes of evidence theory, compared with many existing methods. Properties of the ECR, such as solution’s stability and convergence, have been mathematically proved as well. PMID:26285231

  1. Quasi-Experimental Analysis: A Mixture of Methods and Judgment.

    ERIC Educational Resources Information Center

    Cordray, David S.

    1986-01-01

    The role of human judgment in the development and synthesis of evidence has not been adequately developed or acknowledged within quasi-experimental analysis. Corrective solutions need to confront the fact that causal analysis within complex environments will require a more active assessment that entails reasoning and statistical modeling.…

  2. Passive Facebook usage undermines affective well-being: Experimental and longitudinal evidence.

    PubMed

    Verduyn, Philippe; Lee, David Seungjae; Park, Jiyoung; Shablack, Holly; Orvell, Ariana; Bayer, Joseph; Ybarra, Oscar; Jonides, John; Kross, Ethan

    2015-04-01

    Prior research indicates that Facebook usage predicts declines in subjective well-being over time. How does this come about? We examined this issue in 2 studies using experimental and field methods. In Study 1, cueing people in the laboratory to use Facebook passively (rather than actively) led to declines in affective well-being over time. Study 2 replicated these findings in the field using experience-sampling techniques. It also demonstrated how passive Facebook usage leads to declines in affective well-being: by increasing envy. Critically, the relationship between passive Facebook usage and changes in affective well-being remained significant when controlling for active Facebook use, non-Facebook online social network usage, and direct social interactions, highlighting the specificity of this result. These findings demonstrate that passive Facebook usage undermines affective well-being. (c) 2015 APA, all rights reserved).

  3. Inclusion of quasi-experimental studies in systematic reviews of health systems research.

    PubMed

    Rockers, Peter C; Røttingen, John-Arne; Shemilt, Ian; Tugwell, Peter; Bärnighausen, Till

    2015-04-01

    Systematic reviews of health systems research commonly limit studies for evidence synthesis to randomized controlled trials. However, well-conducted quasi-experimental studies can provide strong evidence for causal inference. With this article, we aim to stimulate and inform discussions on including quasi-experiments in systematic reviews of health systems research. We define quasi-experimental studies as those that estimate causal effect sizes using exogenous variation in the exposure of interest that is not directly controlled by the researcher. We incorporate this definition into a non-hierarchical three-class taxonomy of study designs - experiments, quasi-experiments, and non-experiments. Based on a review of practice in three disciplines related to health systems research (epidemiology, economics, and political science), we discuss five commonly used study designs that fit our definition of quasi-experiments: natural experiments, instrumental variable analyses, regression discontinuity analyses, interrupted times series studies, and difference studies including controlled before-and-after designs, difference-in-difference designs and fixed effects analyses of panel data. We further review current practices regarding quasi-experimental studies in three non-health fields that utilize systematic reviews (education, development, and environment studies) to inform the design of approaches for synthesizing quasi-experimental evidence in health systems research. Ultimately, the aim of any review is practical: to provide useful information for policymakers, practitioners, and researchers. Future work should focus on building a consensus among users and producers of systematic reviews regarding the inclusion of quasi-experiments. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Using semantics for representing experimental protocols.

    PubMed

    Giraldo, Olga; García, Alexander; López, Federico; Corcho, Oscar

    2017-11-13

    An experimental protocol is a sequence of tasks and operations executed to perform experimental research in biological and biomedical areas, e.g. biology, genetics, immunology, neurosciences, virology. Protocols often include references to equipment, reagents, descriptions of critical steps, troubleshooting and tips, as well as any other information that researchers deem important for facilitating the reusability of the protocol. Although experimental protocols are central to reproducibility, the descriptions are often cursory. There is the need for a unified framework with respect to the syntactic structure and the semantics for representing experimental protocols. In this paper we present "SMART Protocols ontology", an ontology for representing experimental protocols. Our ontology represents the protocol as a workflow with domain specific knowledge embedded within a document. We also present the S ample I nstrument R eagent O bjective (SIRO) model, which represents the minimal common information shared across experimental protocols. SIRO was conceived in the same realm as the Patient Intervention Comparison Outcome (PICO) model that supports search, retrieval and classification purposes in evidence based medicine. We evaluate our approach against a set of competency questions modeled as SPARQL queries and processed against a set of published and unpublished protocols modeled with the SP Ontology and the SIRO model. Our approach makes it possible to answer queries such as Which protocols use tumor tissue as a sample. Improving reporting structures for experimental protocols requires collective efforts from authors, peer reviewers, editors and funding bodies. The SP Ontology is a contribution towards this goal. We build upon previous experiences and bringing together the view of researchers managing protocols in their laboratory work. Website: https://smartprotocols.github.io/ .

  5. Evidence for the Formation of Nitrogen-Rich Platinum and Palladium Nitride Nanoparticles

    DOE PAGES

    Veith, Gabriel M.; Lupini, Andrew R.; Baggetto, Loïc; ...

    2013-12-03

    Here, we report evidence for the formation of nitrogen-rich precious metal nanoparticles (Pt, Pd) prepared by reactive sputtering of the pure metal in a N 2 plasma. The composition of the nanoparticles varies as a function of particle size and growth conditions. For the smallest particles the nitrogen content appears to be as high as 6.7 N atoms for each Pd atom or 5.9 N atoms for each Pt atom whereas bulk films have nominal compositions of Pt 7.3N and Pd 2.5N. The nanoparticles are metastable in air and moisture, slowly decomposing over several years. This paper describes the synthesismore » of these materials along with experimental evidence of the composition, oxidation state, and growth modes. Moreover, the catalytic properties of these N-rich nanoparticles were accessed by rotating disk electrode electrochemical studies, the liquid phase oxidation of benzyl alcohol and gas phase CO oxidation and support the experimental evidence for the materials composition.« less

  6. A review of the evidence regarding associations between attachment theory and experimentally induced pain.

    PubMed

    Meredith, Pamela Joy

    2013-04-01

    Theoretical and empirical evidence suggests that adult attachment and pain-related variables are predictably and consistently linked, and that understanding these links may guide pain intervention and prevention efforts. In general, insecure attachment has been portrayed as a risk factor, and secure attachment as a protective factor, for people with chronic pain conditions. In an effort to better understand the relationships among attachment and pain variables, these links have been investigated in pain-free samples using induced-pain techniques. The present paper reviews the available research linking adult attachment and laboratory-induced pain. While the diverse nature of the studies precludes definitive conclusions, together these papers offer support for associations between insecure attachment and a more negative pain experience. The evidence presented in this review highlights areas for further empirical attention, as well as providing some guidance for clinicians who may wish to employ preventive approaches and other interventions informed by attachment theory.

  7. Evidence of negative-index refraction in nonlinear chemical waves.

    PubMed

    Yuan, Xujin; Wang, Hongli; Ouyang, Qi

    2011-05-06

    The negative index of refraction of nonlinear chemical waves has become a recent focus in nonlinear dynamics researches. Theoretical analysis and computer simulations have predicted that the negative index of refraction can occur on the interface between antiwaves and normal waves in a reaction-diffusion (RD) system. However, no experimental evidence has been found so far. In this Letter, we report our experimental design in searching for such a phenomenon in a chlorite-iodide-malonic acid (CIMA) reaction. Our experimental results demonstrate that competition between waves and antiwaves at their interface determines the fate of the wave interaction. The negative index of refraction was only observed when the oscillation frequency of a normal wave is significantly smaller than that of the antiwave. All experimental results were supported by simulations using the Lengyel-Epstein RD model which describes the CIMA reaction-diffusion system.

  8. Experimental evidence that livestock grazing intensity affects the activity of a generalist predator

    NASA Astrophysics Data System (ADS)

    Villar, Nacho; Lambin, Xavier; Evans, Darren; Pakeman, Robin; Redpath, Steve

    2013-05-01

    Grazing by domestic ungulates has substantial impacts on ecosystem structure and composition. In grasslands of the northern hemisphere, livestock grazing limits populations of small mammals, which are a main food source for a variety of vertebrate predators. However, no experimental studies have described the impact of livestock grazing on vertebrate predators. We experimentally manipulated sheep and cattle grazing intensity in the Scottish uplands to test its impact on a relatively abundant small mammal, the field vole (Microtus agrestis), and its archetypal generalist predator, the red fox (Vulpes vulpes). We demonstrate that ungulate grazing had a strong consistent negative impact on both vole densities and indices of fox activity. Ungulate grazing did not substantially affect the relationship between fox activity and vole densities. However, the data suggested that, as grazing intensity increased i) fox activity indices tended to be higher when vole densities were low, and ii) the relationship between fox activity and vole density was weaker. All these patterns are surprising given the relative small scale of our experiment compared to large red fox territories in upland habitats of Britain, and suggest that domestic grazing intensity causes a strong response in the activity of generalist predators important for their conservation in grassland ecosystems.

  9. Evidence for robots.

    PubMed

    Shenoy, Ravikiran; Nathwani, Dinesh

    2017-01-01

    Robots have been successfully used in commercial industry and have enabled humans to perform tasks which are repetitive, dangerous and requiring extreme force. Their role has evolved and now includes many aspects of surgery to improve safety and precision. Orthopaedic surgery is largely performed on bones which are rigid immobile structures which can easily be performed by robots with great precision. Robots have been designed for use in orthopaedic surgery including joint arthroplasty and spine surgery. Experimental studies have been published evaluating the role of robots in arthroscopy and trauma surgery. In this article, we will review the incorporation of robots in orthopaedic surgery looking into the evidence in their use. © The Authors, published by EDP Sciences, 2017.

  10. Evidence for robots

    PubMed Central

    Shenoy, Ravikiran; Nathwani, Dinesh

    2017-01-01

    Robots have been successfully used in commercial industry and have enabled humans to perform tasks which are repetitive, dangerous and requiring extreme force. Their role has evolved and now includes many aspects of surgery to improve safety and precision. Orthopaedic surgery is largely performed on bones which are rigid immobile structures which can easily be performed by robots with great precision. Robots have been designed for use in orthopaedic surgery including joint arthroplasty and spine surgery. Experimental studies have been published evaluating the role of robots in arthroscopy and trauma surgery. In this article, we will review the incorporation of robots in orthopaedic surgery looking into the evidence in their use. PMID:28534472

  11. Experimental evidence for chick discrimination without recognition in a brood parasite host

    PubMed Central

    Grim, Tomáš

    2006-01-01

    Recognition is considered a critical basis for discriminatory behaviours in animals. Theoretically, recognition and discrimination of parasitic chicks are not predicted to evolve in hosts of brood parasitic birds that evict nest-mates. Yet, an earlier study showed that host reed warblers (Acrocephalus scirpaceus) of an evicting parasite, the common cuckoo (Cuculus canorus), can avoid the costs of prolonged care for unrelated young by deserting the cuckoo chick before it fledges. Desertion was not based on specific recognition of the parasite because hosts accept any chick cross-fostered into their nests. Thus, the mechanism of this adaptive host response remains enigmatic. Here, I show experimentally that the cue triggering this ‘discrimination without recognition’ behaviour is the duration of parental care. Neither the intensity of brood care nor the presence of a single-chick in the nest could explain desertions. Hosts responded similarly to foreign chicks, whether heterospecific or experimental conspecifics. The proposed mechanism of discrimination strikingly differs from those found in other parasite–host systems because hosts do not need an internal recognition template of the parasite's appearance to effectively discriminate. Thus, host defences against parasitic chicks may be based upon mechanisms qualitatively different from those operating against parasitic eggs. I also demonstrate that this discriminatory mechanism is non-costly in terms of recognition errors. Comparative data strongly suggest that parasites cannot counter-evolve any adaptation to mitigate effects of this host defence. These findings have crucial implications for the process and end-result of host–parasite arms races and our understanding of the cognitive basis of discriminatory mechanisms in general. PMID:17164201

  12. Gluconeogenesis in the ruminant fetus: evaluation of conflicting evidence from radiotracer and other experimental techniques

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Prior, R.L.

    1982-01-01

    Conflicting evidence exists as to whether the gluconeogenetic process is active in the late gestation fetal lamb. In vitro evidence based on measurements of enzyme activity and substrate flux into glucose indicates that the capacity for gluconeogenesis exists in fetal liver. The in vivo conversion of (/sup 14/C)lactate and (/sup 14/C)alanine into glucose in the lamb fetus has been demonstrated. Lactate and alanine account for 49 and 2.3% of the fetal glucose pool, respectively. Although gluconeogenesis can occur in the fetal lamb, alterations in net rates of umbilical uptake of glucose or lactate, fetal blood glucose concentrations, fetal or maternalmore » glucose replacement rates, or maternal nutrition may alter the observed rates of fetal gluconeogenesis.« less

  13. Fayalite Oxidation Processes: Experimental Evidence for the Stability of Pure Ferric Fayalite?

    NASA Technical Reports Server (NTRS)

    Martin, A. M.; Righter, K.; Keller, L. P.; Medard, E.; Devouard, B.; Rahman, Z.

    2011-01-01

    Olivine is one of the most important minerals in Earth and planetary sciences. Fayalite Fe2(2+)SiO4, the ferrous end-member of olivine, is present in some terrestrial rocks and primitive meteorites (CV3 chondrites). A ferric fayalite (or ferri-fayalite), Fe(2+) Fe2(3+)(SiO4)2 laihunite, has been reported in Earth samples (magnetite ore, metamorphic and volcanic rocks...) and in Martian meteorites (nakhlites). Laihunite was also synthesized at 1 atmosphere between 400 and 700 C. We show evidence for the stability of a pure ferrifayalite end-member and for potential minerals with XFe(3+) between 2/3 and 1.

  14. Links between Parents' Epistemological Stance and Children's Evidence Talk

    ERIC Educational Resources Information Center

    Luce, Megan R.; Callanan, Maureen A.; Smilovic, Sarah

    2013-01-01

    Recent experimental research highlights young children's selectivity in learning from others. Little is known, however, about the patterns of information that children actually encounter in conversations with adults. This study investigated variation in parents' tendency to focus on testable evidence as a way to answer science-related questions…

  15. A search for the evidence supporting community paediatric practice

    PubMed Central

    Rudolf, M; Lyth, N; Bundle, A; Rowland, G; Kelly, A; Bosson, S; Garner, M; Guest, P; Khan, M; Thazin, R; Bennett, T; Damman, D; Cove, V; Kaur, V

    1999-01-01

    AIM—Controversy exists regarding the evidence base of medicine. Estimates range from 20% to 80% in various specialties, but there have been no studies in paediatrics. The aim of this study was to ascertain the evidence base for community paediatrics.
METHODS—Twelve community paediatricians working in clinics and schools in Yorkshire, Manchester, Teesside, and Cheshire carried out a prospective review of consecutive clinical contacts. Evidence for diagnostic processes, prescribing, referrals, counselling/advice, and child health promotion was found by searching electronic databases. This information was critically appraised and a consensus was obtained regarding quality and whether it supported actions taken.
RESULTS—Two hundred and forty seven consultations and 1149 clinical actions were performed. Good evidence was found from a randomised controlled trial or other appropriate study for 39.9% of the 629actions studied; convincing non-experimental evidence for 7%; inconclusive evidence for 25.4%; evidence of ineffectiveness for 0.2%; and no evidence for 27.5%. Prescribing and child health promotion activities had the highest levels of quality evidence, and counselling/advice had the lowest.
CONCLUSIONS—An encouraging amount of evidence was found to support much of community paediatric practice. This study improved on previous research in other specialties because actions other than medications and surgery were included.

 PMID:10325707

  16. James Franck, the ionization potential of helium, and the experimental discovery of metastable states

    NASA Astrophysics Data System (ADS)

    Gearhart, Clayton A.

    2017-11-01

    In 1920, James Franck together with Fritz Reiche and Paul Knipping found strong experimental evidence that the lowest-lying triplet state in helium is metastable-an atom in this state cannot make a spontaneous transition to the ground state. Even though their evidence was entirely experimental, they tied their results almost inextricably to Alfred Landé's 1919 model of the helium atom, and in the process, misunderstood the new theoretical selection rules of Adalbert Rubinowicz and Niels Bohr. In an additional complication, experiments of the English physicists Frank Horton and Ann Catherine Davies contradicted Franck's. Although Franck's result has held up, the reasons for the discrepancies remain unclear.

  17. [Authentication of Trace Material Evidence in Forensic Science Field with Infrared Microscopic Technique].

    PubMed

    Jiang, Zhi-quan; Hu, Ke-liang

    2016-03-01

    In the field of forensic science, conventional infrared spectral analysis technique is usually unable to meet the detection requirements, because only very a few trace material evidence with diverse shapes and complex compositions, can be extracted from the crime scene. Infrared microscopic technique is developed based on a combination of Fourier-transform infrared spectroscopic technique and microscopic technique. Infrared microscopic technique has a lot of advantages over conventional infrared spectroscopic technique, such as high detection sensitivity, micro-area analysisand nondestructive examination. It has effectively solved the problem of authentication of trace material evidence in the field of forensic science. Additionally, almost no external interference is introduced during measurements by infrared microscopic technique. It can satisfy the special need that the trace material evidence must be reserved for witness in court. It is illustrated in detail through real case analysis in this experimental center that, infrared microscopic technique has advantages in authentication of trace material evidence in forensic science field. In this paper, the vibration features in infrared spectra of material evidences, including paints, plastics, rubbers, fibers, drugs and toxicants, can be comparatively analyzed by means of infrared microscopic technique, in an attempt to provide powerful spectroscopic evidence for qualitative diagnosis of various criminal and traffic accident cases. The experimental results clearly suggest that infrared microscopic technique has an incomparable advantage and it has become an effective method for authentication of trace material evidence in the field of forensic science.

  18. Experimental study of isolas in nonlinear systems featuring modal interactions

    PubMed Central

    Noël, Jean-Philippe; Virgin, Lawrence N.; Kerschen, Gaëtan

    2018-01-01

    The objective of the present paper is to provide experimental evidence of isolated resonances in the frequency response of nonlinear mechanical systems. More specifically, this work explores the presence of isolas, which are periodic solutions detached from the main frequency response, in the case of a nonlinear set-up consisting of two masses sliding on a horizontal guide. A careful experimental investigation of isolas is carried out using responses to swept-sine and stepped-sine excitations. The experimental findings are validated with advanced numerical simulations combining nonlinear modal analysis and bifurcation monitoring. In particular, the interactions between two nonlinear normal modes are shown to be responsible for the creation of the isolas. PMID:29584758

  19. The Use and Interpretation of Quasi-Experimental Studies in Medical Informatics

    PubMed Central

    Harris, Anthony D.; McGregor, Jessina C.; Perencevich, Eli N.; Furuno, Jon P.; Zhu, Jingkun; Peterson, Dan E.; Finkelstein, Joseph

    2006-01-01

    Quasi-experimental study designs, often described as nonrandomized, pre-post intervention studies, are common in the medical informatics literature. Yet little has been written about the benefits and limitations of the quasi-experimental approach as applied to informatics studies. This paper outlines a relative hierarchy and nomenclature of quasi-experimental study designs that is applicable to medical informatics intervention studies. In addition, the authors performed a systematic review of two medical informatics journals, the Journal of the American Medical Informatics Association (JAMIA) and the International Journal of Medical Informatics (IJMI), to determine the number of quasi-experimental studies published and how the studies are classified on the above-mentioned relative hierarchy. They hope that future medical informatics studies will implement higher level quasi-experimental study designs that yield more convincing evidence for causal links between medical informatics interventions and outcomes. PMID:16221933

  20. Experimental evidence for the influence of cognitions on compulsive buying.

    PubMed

    McQueen, Paul; Moulding, Richard; Kyrios, Michael

    2014-12-01

    Compulsive buying is a disabling condition, where individuals are unable to resist or control their buying behavior, leading to substantial social and financial problems. Cognitive models implicate the role of beliefs as one factor in buying behavior, for example, "this item is unique and will help me improve my life". This study experimentally examined the contribution of such beliefs to the disorder, in individuals who compulsively buy (N = 18) and in non-clinical controls (N = 17). Participants were presented with photographs of idiosyncratically appealing and unappealing items, in the context of imagined scenarios that either minimized or maximized aspects relevant to hypothesized "compulsive buying beliefs" (i.e., beliefs that acquisition can compensate for negative feelings, beliefs regarding uniqueness and lost opportunities, and emotional reasons for buying). It was found that individuals who compulsively buy demonstrated stronger urges to purchase than control participants, regardless of context, but the overall strength of these urges was responsive to manipulations of beliefs about consumer items said to be associated with compulsive buying. The main limitation of the study was a small sample size, potentially reducing power. Nonetheless, these findings provide insights into the processes underlying compulsive phenomena, in particular supporting the role of cognitions in compulsive buying. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Mimicking Aphasic Semantic Errors in Normal Speech Production: Evidence from a Novel Experimental Paradigm

    ERIC Educational Resources Information Center

    Hodgson, Catherine; Lambon Ralph, Matthew A.

    2008-01-01

    Semantic errors are commonly found in semantic dementia (SD) and some forms of stroke aphasia and provide insights into semantic processing and speech production. Low error rates are found in standard picture naming tasks in normal controls. In order to increase error rates and thus provide an experimental model of aphasic performance, this study…

  2. Experimental evidence for stochastic switching of supercooled phases in NdNiO3 nanostructures

    NASA Astrophysics Data System (ADS)

    Kumar, Devendra; Rajeev, K. P.; Alonso, J. A.

    2018-03-01

    A first-order phase transition is a dynamic phenomenon. In a multi-domain system, the presence of multiple domains of coexisting phases averages out the dynamical effects, making it nearly impossible to predict the exact nature of phase transition dynamics. Here, we report the metal-insulator transition in samples of sub-micrometer size NdNiO3 where the effect of averaging is minimized by restricting the number of domains under study. We observe the presence of supercooled metallic phases with supercooling of 40 K or more. The transformation from the supercooled metallic to the insulating state is a stochastic process that happens at different temperatures and times in different experimental runs. The experimental results are understood without incorporating material specific properties, suggesting that the behavior is of universal nature. The size of the sample needed to observe individual switching of supercooled domains, the degree of supercooling, and the time-temperature window of switching are expected to depend on the parameters such as quenched disorder, strain, and magnetic field.

  3. Experimental Evidence for Quantum Interference and Vibrationally Induced Decoherence in Single-Molecule Junctions

    NASA Astrophysics Data System (ADS)

    Ballmann, Stefan; Härtle, Rainer; Coto, Pedro B.; Elbing, Mark; Mayor, Marcel; Bryce, Martin R.; Thoss, Michael; Weber, Heiko B.

    2012-08-01

    We analyze quantum interference and decoherence effects in single-molecule junctions both experimentally and theoretically by means of the mechanically controlled break junction technique and density-functional theory. We consider the case where interference is provided by overlapping quasidegenerate states. Decoherence mechanisms arising from electronic-vibrational coupling strongly affect the electrical current flowing through a single-molecule contact and can be controlled by temperature variation. Our findings underline the universal relevance of vibrations for understanding charge transport through molecular junctions.

  4. Experimental evidence for quantum interference and vibrationally induced decoherence in single-molecule junctions.

    PubMed

    Ballmann, Stefan; Härtle, Rainer; Coto, Pedro B; Elbing, Mark; Mayor, Marcel; Bryce, Martin R; Thoss, Michael; Weber, Heiko B

    2012-08-03

    We analyze quantum interference and decoherence effects in single-molecule junctions both experimentally and theoretically by means of the mechanically controlled break junction technique and density-functional theory. We consider the case where interference is provided by overlapping quasidegenerate states. Decoherence mechanisms arising from electronic-vibrational coupling strongly affect the electrical current flowing through a single-molecule contact and can be controlled by temperature variation. Our findings underline the universal relevance of vibrations for understanding charge transport through molecular junctions.

  5. New insights into the negative thermal expansion: Direct experimental evidence for the “guitar-string” effect in cubic ScF 3

    DOE PAGES

    Hu, Lei; Chen, Jun; Sanson, Andrea; ...

    2016-06-23

    The understanding of the negative thermal expansion (NTE) mechanism remains challenging but critical for the development of NTE materials. This study sheds light on NTE of ScF 3, one of the most outstanding materials with NTE. The local dynamics of ScF 3 has been investigated by a combined analysis of synchrotron-based X-ray total scattering, ex-tended X-ray absorption fine structure and neutron powder diffraction. Very interestingly, we observe that i) the Sc-F nearest-neighbor distance strongly expands with increasing temperature while the Sc-Sc next-nearest-neighbor distance contracts, ii) the thermal ellipsoids of relative vibrations be-tween Sc-F nearest-neighbors are highly elongated in the directionmore » perpendicular to the Sc-F bond, indicating that the Sc-F bond is much softer to bend than to stretch, and iii) there is mainly dynamically transverse motion of fluorine atoms, rather than static shifts. Here, these results are the direct experimental evidence for the NTE mechanism, in which the rigid unit is not necessary for the occurrence of NTE, and the key role is played by the transverse thermal vibrations of fluorine atoms through the “guitar-string” effect.« less

  6. "No Excuses" Charter Schools: A Meta-Analysis of the Experimental Evidence on Student Achievement

    ERIC Educational Resources Information Center

    Cheng, Albert; Hitt, Collin; Kisida, Brian; Mills, Jonathan N.

    2017-01-01

    Many most well-known charter schools in the United States use a "No Excuses" approach. We conduct the first meta-analysis of the achievement impacts of No Excuses charter schools, focusing on experimental, lottery-based studies. We estimate that No Excuses charter schools increase student math and literacy achievement by 0.25 and 0.17,…

  7. Effectiveness of Student Learning during Experimental Work in Primary School.

    PubMed

    Logar, Ana; Peklaj, Cirila; Ferk Savec, Vesna

    2017-09-01

    The aim of the research was to optimize the effectiveness of student learning based on experimental work in chemistry classes in Slovenian primary schools. To obtain evidence about how experimental work is implemented during regular chemistry classes, experimental work was videotaped during 19 units of chemistry lessons at 12 Slovenian primary schools from the pool of randomly selected schools. Altogether 332 eight-grade students were involved in the investigation, with an average age of 14.2 years. Students were videotaped during chemistry lessons, and their worksheets were collected afterward. The 12 chemistry teachers, who conducted lessons in these schools, were interviewed before the lessons; their teaching plans were also collected. The collected data was analyzed using qualitative methods. The results indicate that many teachers in Slovenian primary schools are not fully aware of the potential of experimental work integrated into chemistry lessons for the development of students' experimental competence. Further research of the value of different kinds of training to support teachers for the use of experimental work in chemistry teaching is needed.

  8. Eliciting health care priorities in developing countries: experimental evidence from Guatemala.

    PubMed

    Font, Joan Costa; Forns, Joan Rovira; Sato, Azusa

    2016-02-01

    Although some methods for eliciting preferences to assist participatory priority setting in health care in developed countries are available, the same is not true for poor communities in developing countries whose preferences are neglected in health policy making. Existing methods grounded on self-interested, monetary valuations that may be inappropriate for developing country settings where community care is provided through 'social allocation' mechanisms. This paper proposes and examines an alternative methodology for eliciting preferences for health care programmes specifically catered for rural and less literate populations but which is still applicable in urban communities. Specifically, the method simulates a realistic collective budget allocation experiment, to be implemented in both rural and urban communities in Guatemala. We report evidence revealing that participatory budget-like experiments are incentive compatible mechanisms suitable for revealing collective preferences, while simultaneously having the advantage of involving communities in health care reform processes. © The Author 2015. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine.

  9. Interventions for acute stroke management in Africa: a systematic review of the evidence.

    PubMed

    Baatiema, Leonard; Chan, Carina K Y; Sav, Adem; Somerset, Shawn

    2017-10-24

    The past decades have witnessed a rapid evolution of research on evidence-based acute stroke care interventions worldwide. Nonetheless, the evidence-to-practice gap in acute stroke care remains variable with slow and inconsistent uptake in low-middle income countries (LMICs). This review aims to identify and compare evidence-based acute stroke management interventions with alternative care on overall patient mortality and morbidity outcomes, functional independence, and length of hospital stay across Africa. This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. An electronic search was conducted in six databases comprising MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science, Academic Search Complete and Cochrane Library for experimental and non-experimental studies. Eligible studies were abstracted into evidence tables and their methodological quality appraised using the Joanna Briggs Institute checklist. Data were analysed and presented narratively with reference to observed differences in patient outcomes, reporting p values and confidence intervals for any possible relationship. Initially, 1896 articles were identified and 37 fully screened. Four non-experimental studies (three cohort and one case series studies) were included in the final review. One study focused on the clinical efficacy of a stroke unit whilst the remaining three reported on thrombolytic therapy. The results demonstrated a reduction in patient deaths attributed to stroke unit care and thrombolytic therapy. Thrombolytic therapy was also associated with reductions in symptomatic intracerebral haemorrhage (SICH). However, the limited eligible studies and methodological limitations compromised definitive conclusions on the extent of and level of efficacy of evidence-based acute stroke care interventions across Africa. Evidence from this review confirms the widespread

  10. Facilitating healthcare decisions by assessing the certainty in the evidence from preclinical animal studies.

    PubMed

    Hooijmans, Carlijn R; de Vries, Rob B M; Ritskes-Hoitinga, Merel; Rovers, Maroeska M; Leeflang, Mariska M; IntHout, Joanna; Wever, Kimberley E; Hooft, Lotty; de Beer, Hans; Kuijpers, Ton; Macleod, Malcolm R; Sena, Emily S; Ter Riet, Gerben; Morgan, Rebecca L; Thayer, Kristina A; Rooney, Andrew A; Guyatt, Gordon H; Schünemann, Holger J; Langendam, Miranda W

    2018-01-01

    Laboratory animal studies are used in a wide range of human health related research areas, such as basic biomedical research, drug research, experimental surgery and environmental health. The results of these studies can be used to inform decisions regarding clinical research in humans, for example the decision to proceed to clinical trials. If the research question relates to potential harms with no expectation of benefit (e.g., toxicology), studies in experimental animals may provide the only relevant or controlled data and directly inform clinical management decisions. Systematic reviews and meta-analyses are important tools to provide robust and informative evidence summaries of these animal studies. Rating how certain we are about the evidence could provide important information about the translational probability of findings in experimental animal studies to clinical practice and probably improve it. Evidence summaries and certainty in the evidence ratings could also be used (1) to support selection of interventions with best therapeutic potential to be tested in clinical trials, (2) to justify a regulatory decision limiting human exposure (to drug or toxin), or to (3) support decisions on the utility of further animal experiments. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach is the most widely used framework to rate the certainty in the evidence and strength of health care recommendations. Here we present how the GRADE approach could be used to rate the certainty in the evidence of preclinical animal studies in the context of therapeutic interventions. We also discuss the methodological challenges that we identified, and for which further work is needed. Examples are defining the importance of consistency within and across animal species and using GRADE's indirectness domain as a tool to predict translation from animal models to humans.

  11. Facilitating healthcare decisions by assessing the certainty in the evidence from preclinical animal studies

    PubMed Central

    Hooijmans, Carlijn R.; de Vries, Rob B. M.; Ritskes-Hoitinga, Merel; Rovers, Maroeska M.; Leeflang, Mariska M.; IntHout, Joanna; Wever, Kimberley E.; Hooft, Lotty; de Beer, Hans; Kuijpers, Ton; Macleod, Malcolm R.; Sena, Emily S.; ter Riet, Gerben; Morgan, Rebecca L.; Thayer, Kristina A.; Rooney, Andrew A.; Guyatt, Gordon H.; Schünemann, Holger J.

    2018-01-01

    Laboratory animal studies are used in a wide range of human health related research areas, such as basic biomedical research, drug research, experimental surgery and environmental health. The results of these studies can be used to inform decisions regarding clinical research in humans, for example the decision to proceed to clinical trials. If the research question relates to potential harms with no expectation of benefit (e.g., toxicology), studies in experimental animals may provide the only relevant or controlled data and directly inform clinical management decisions. Systematic reviews and meta-analyses are important tools to provide robust and informative evidence summaries of these animal studies. Rating how certain we are about the evidence could provide important information about the translational probability of findings in experimental animal studies to clinical practice and probably improve it. Evidence summaries and certainty in the evidence ratings could also be used (1) to support selection of interventions with best therapeutic potential to be tested in clinical trials, (2) to justify a regulatory decision limiting human exposure (to drug or toxin), or to (3) support decisions on the utility of further animal experiments. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach is the most widely used framework to rate the certainty in the evidence and strength of health care recommendations. Here we present how the GRADE approach could be used to rate the certainty in the evidence of preclinical animal studies in the context of therapeutic interventions. We also discuss the methodological challenges that we identified, and for which further work is needed. Examples are defining the importance of consistency within and across animal species and using GRADE’s indirectness domain as a tool to predict translation from animal models to humans. PMID:29324741

  12. Evidence Combination From an Evolutionary Game Theory Perspective.

    PubMed

    Deng, Xinyang; Han, Deqiang; Dezert, Jean; Deng, Yong; Shyr, Yu

    2016-09-01

    Dempster-Shafer evidence theory is a primary methodology for multisource information fusion because it is good at dealing with uncertain information. This theory provides a Dempster's rule of combination to synthesize multiple evidences from various information sources. However, in some cases, counter-intuitive results may be obtained based on that combination rule. Numerous new or improved methods have been proposed to suppress these counter-intuitive results based on perspectives, such as minimizing the information loss or deviation. Inspired by evolutionary game theory, this paper considers a biological and evolutionary perspective to study the combination of evidences. An evolutionary combination rule (ECR) is proposed to help find the most biologically supported proposition in a multievidence system. Within the proposed ECR, we develop a Jaccard matrix game to formalize the interaction between propositions in evidences, and utilize the replicator dynamics to mimick the evolution of propositions. Experimental results show that the proposed ECR can effectively suppress the counter-intuitive behaviors appeared in typical paradoxes of evidence theory, compared with many existing methods. Properties of the ECR, such as solution's stability and convergence, have been mathematically proved as well.

  13. Evidence Evaluation: Measure "Z" Corresponds to Human Utility Judgments Better than Measure "L" and Optimal-Experimental-Design Models

    ERIC Educational Resources Information Center

    Rusconi, Patrice; Marelli, Marco; D'Addario, Marco; Russo, Selena; Cherubini, Paolo

    2014-01-01

    Evidence evaluation is a crucial process in many human activities, spanning from medical diagnosis to impression formation. The present experiments investigated which, if any, normative model best conforms to people's intuition about the value of the obtained evidence. Psychologists, epistemologists, and philosophers of science have proposed…

  14. [GRADE system: classification of quality of evidence and strength of recommendation].

    PubMed

    Aguayo-Albasini, José Luis; Flores-Pastor, Benito; Soria-Aledo, Víctor

    2014-02-01

    The acquisition and classification of scientific evidence, and subsequent formulation of recommendations constitute the basis for the development of clinical practice guidelines. There are several systems for the classification of evidence and strength of recommendations; the most commonly used nowadays is the Grading of Recommendations, Assessment, Development and Evaluation system (GRADE). The GRADE system initially classifies the evidence into high or low, coming from experimental or observational studies; subsequently and following a series of considerations, the evidence is classified into high, moderate, low or very low. The strength of recommendations is based not only on the quality of the evidence, but also on a series of factors such as the risk/benefit balance, values and preferences of the patients and professionals, and the use of resources or costs. Copyright © 2013 AEC. Published by Elsevier Espana. All rights reserved.

  15. An experimental study of the job demand-control model with measures of heart rate variability and salivary alpha-amylase: Evidence of increased stress responses to increased break autonomy.

    PubMed

    O'Donnell, Emma; Landolt, Kathleen; Hazi, Agnes; Dragano, Nico; Wright, Bradley J

    2015-01-01

    We assessed in an experimental design whether the stress response towards a work task was moderated by the autonomy to choose a break during the assigned time to complete the task. This setting is defined in accordance with the theoretical framework of the job-demand-control (JDC) model of work related stress. The findings from naturalistic investigations of a stress-buffering effect of autonomy (or 'buffer hypothesis') are equivocal and the experimental evidence is limited, especially with relation to physiological indices of stress. Our objective was to investigate if increased autonomy in a particular domain (break time control) was related with adaptive physiology using objective physiological markers of stress; heart rate variability (HRV) and salivary alpha amylase (sAA). We used a within-subject design and the 60 female participants were randomly assigned to an autonomy (free timing of break) and standard conditions (fixed timing of break) of a word processing task in a simulated office environment in a random order. Participants reported increased perceptions of autonomy, no difference in demand and performed worse in the task in the break-time autonomy versus the standard condition. The results revealed support for the manipulation of increased autonomy, but in the opposing direction. Increased autonomy was related with dysregulated physiological reactivity, synonymous with typical increased stress responses. Potentially, our findings may indicate that autonomy is not necessary a resource but could become an additional stressor when it adds additional complexity while the amount of work (demands) remains unchanged. Further, our findings underscore the need to collect objective physiological evidence of stress to supplement self-reported information. Self-report biases may partially explain the inconsistent findings with the buffer hypothesis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Time travel, Clock Puzzles and Their Experimental Tests

    NASA Astrophysics Data System (ADS)

    Ciufolini, Ignazio

    2013-09-01

    Is time travel possible? What is Einstein's theory of relativity mathematically predicting in that regard? Is time travel related to the so-called clock `paradoxes' of relativity and if so how? Is there any accurate experimental evidence of the phenomena regarding the different flow of time predicted by General Relativity and is there any possible application of the temporal phenomena predicted by relativity to our everyday life? Which temporal phenomena are predicted in the vicinities of a rotating body and of a mass-energy current, and do we have any experimental test of the occurrence of these phenomena near a rotating body? In this paper, we address and answer some of these questions.

  17. The interdependence of perceived confession voluntariness and case evidence.

    PubMed

    Greenspan, Rachel; Scurich, Nicholas

    2016-12-01

    The current research investigated the mechanisms by which perceptions of confession evidence both influence and are influenced by perceptions of other case evidence using the theoretical framework of coherence-based reasoning (CBR). CBR posits that ambiguity and uncertainty are eschewed by artificially imposing consistency between pieces of evidence through bidirectional reasoning: Inferences about evidence lead to a preferred verdict, which in turn radiates backward to influence the perception of evidence. Two studies tested the CBR account with regard to confessions. An online sample of participants evaluated confession and nonconfession evidence at pretest and posttest. Study 1 revealed that, during pretest, participants (N = 119) deemed the evidence independent and nonprobative and the confession to be voluntary. However, at posttest, in the context of a criminal trial, participants considered the same evidence interrelated and highly inculpatory or exculpatory, depending on their verdict. Moreover, participants who voted to convict deemed the confession substantially voluntary, whereas participants who voted to acquit deemed it involuntary. Study 2 experimentally manipulated the strength of the nonconfession evidence in an effort to push participants (N = 127) toward a particular verdict. The same patterns of results emerged but were conditional on the strength of the nonconfession evidence: Strong case evidence caused the confession to be perceived as more voluntary, despite the fact that the confession was held constant. These findings replicate the coherence effect in a new domain and suggest that judges conducting harmless error analysis or making admissibility decisions might underappreciate the impact of confession evidence on jurors' verdicts. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  18. Experimental evidence of a dual endocrine control of biosynthesis in the main nidamental glands of Sepia officinalis L. by factors from the central nervous system and the ovary.

    PubMed

    Henry, J; Boucaud-Camou, E

    1993-12-01

    1. A rapid, reliable and quantitative in vitro bioassay was developed to study the endocrine control of the biosynthesis of the egg capsule: incorporation of 14C-labelled D-glucose in polysaccharides and glycoproteins increased in dispersed-cell suspensions of main nidamental glands from maturing females. 2. Brain, optic lobes (OL) and ovary extracts from mature and maturing females stimulated the incorporation of 14C-labelled D-glucose in polysaccharidic and glycoproteic fractions of a nidamental cell suspension, whereas optic gland (OG) had no effect. 3. These results bring the first experimental evidence that one of the spawning events (egg-capsule edification) is controlled by the central nervous system and the ovary in a cephalopod.

  19. Review: fetal programming of polycystic ovary syndrome by androgen excess: evidence from experimental, clinical, and genetic association studies.

    PubMed

    Xita, Nectaria; Tsatsoulis, Agathocles

    2006-05-01

    Polycystic ovary syndrome (PCOS) is a common endocrine disorder of premenopausal women, characterized by hyperandrogenism, polycystic ovaries, and chronic anovulation along with insulin resistance and abdominal obesity as frequent metabolic traits. Although PCOS manifests clinically during adolescence, emerging data suggest that the natural history of PCOS may originate in intrauterine life. Evidence from experimental, clinical, and genetic research supporting the hypothesis for the fetal origins of PCOS has been analyzed. Female primates, exposed in utero to androgen excess, exhibit the phenotypic features of PCOS during adult life. Clinical observations also support a potential fetal origin of PCOS. Women with fetal androgen excess disorders, including congenital 21-hydroxylase deficiency and congenital adrenal virilizing tumors, develop features characteristic of PCOS during adulthood despite the normalization of androgen excess after birth. The potential mechanisms of fetal androgen excess leading to a PCOS phenotype in humans are not clearly understood. However, maternal and/or fetal hyperandrogenism can provide a plausible mechanism for fetal programing of PCOS, and this, in part, may be genetically determined. Thus, genetic association studies have indicated that common polymorphic variants of genes determining androgen activity or genes that influence the availability of androgens to target tissues are associated with PCOS and increased androgen levels. These genomic variants may provide the genetic link to prenatal androgenization in human PCOS. Prenatal androgenization of the female fetus induced by genetic and environmental factors, or the interaction of both, may program differentiating target tissues toward the development of PCOS phenotype in adult life.

  20. Experimental evidence for a transverse magnetization of the Abrikosov lattice in anisotropic superconductors

    NASA Technical Reports Server (NTRS)

    Farrel, D. E.; Williams, C. M.; Wolf, S. A.; Bansal, N. P.; Kogan, V. G.

    1988-01-01

    The torque on a superconductor in a magnetic field H has been thought to be dominated by trapped flux or sample shape effects, but it has recently been suggested that an anisotropic type-II material should experience an intrinsic torque for H(c1) much less than H, which in turn is less than H(c2). The predicted phenomenon results from transverse magnetization of the Abrikosov lattice. Measurements are presented on copper-oxide superconductors which delineate the experimental regime in which extrinsic effects are negligible and confirm the existence of the predicted intrinsic torque.

  1. A critical review of RHIC experimental results

    NASA Astrophysics Data System (ADS)

    Trainor, Thomas A.

    2014-07-01

    The relativistic heavy-ion collider (RHIC) was constructed to achieve an asymptotic state of nuclear matter in heavy-ion collisions, a near-ideal gas of deconfined quarks and gluons denoted quark-gluon plasma or QGP. RHIC collisions are indeed very different from the hadronic processes observed at the Bevalac and AGS, but high-energy elementary-collision mechanisms are also non-hadronic. The two-component model (TCM) combines measured properties of elementary collisions with the Glauber eikonal model to provide an alternative asymptotic limit for A-A collisions. RHIC data have been interpreted to indicate formation of a strongly-coupled QGP (sQGP) or "perfect liquid". In this review, I consider the experimental evidence that seems to support such conclusions and alternative evidence that may conflict with those conclusions and suggest different interpretations.

  2. Density functional theory calculations establish the experimental evidence of the DX center atomic structure in CdTe.

    PubMed

    Lany, Stephan; Wolf, Herbert; Wichert, Thomas

    2004-06-04

    The In DX center and the DX-like configuration of the Cd host atom in CdTe are investigated using density functional theory. The simultaneous calculation of the atomic structure and the electric field gradient (EFG) allows one to correlate the theoretically predicted structure of the DX center with an experimental observable, namely, the EFG obtained from radioactive 111In/111Cd probe atoms in In doped CdTe. In this way, the experimental identification of the DX center structure is established.

  3. Experimental Models of Maternal Obesity and Neuroendocrine Programming of Metabolic Disorders in Offspring.

    PubMed

    Reynolds, Clare M; Segovia, Stephanie A; Vickers, Mark H

    2017-01-01

    Evidence from epidemiological, clinical, and experimental studies have clearly shown that disease risk in later life is increased following a poor early life environment, a process preferentially termed developmental programming. In particular, this work clearly highlights the importance of the nutritional environment during early development with alterations in maternal nutrition, including both under- and overnutrition, increasing the risk for a range of cardiometabolic and neurobehavioral disorders in adult offspring characterized by both adipokine resistance and obesity. Although the mechanistic basis for such developmental programming is not yet fully defined, a common feature derived from experimental animal models is that of alterations in the wiring of the neuroendocrine pathways that control energy balance and appetite regulation during early stages of developmental plasticity. The adipokine leptin has also received significant attention with clear experimental evidence that normal regulation of leptin levels during the early life period is critical for the normal development of tissues and related signaling pathways that are involved in metabolic and cardiovascular homeostasis. There is also increasing evidence that alterations in the epigenome and other underlying mechanisms including an altered gut-brain axis may contribute to lasting cardiometabolic dysfunction in offspring. Ongoing studies that further define the mechanisms between these associations will allow for identification of early risk markers and implementation of strategies around interventions that will have obvious beneficial implications in breaking a programmed transgenerational cycle of metabolic disorders.

  4. Prediction and Experimental Evidence for Thermodynamically Stable Charged Orbital Domain Walls

    DOE PAGES

    Li, Qing’an; Gray, K. E.; Wilkins, S. B.; ...

    2014-08-18

    On theoretical grounds, we show that orbital domain walls (ODWs), which are known to exist in the charge and orbital ordered layered manganite LaSr 2Mn 2O 7, should be partially charged as a result of competition between orbital-induced strain and Coulomb repulsion. Furthermore, this unexpected result provides the necessary condition for the known thermodynamic stability of these ODWs, which are unlike the more typical domain walls that arise only from an external field. We offer experimental data consistent with this theoretical framework through a combined transport and x-ray-diffraction study. In particular, our transport data on this charge and orbital orderedmore » manganite exhibit abrupt transformations to higher conductance at a threshold electric field. As transport phenomena closely resemble effects found for sliding charge-density waves (SCDWs) in pseudo-one-dimensional (1D) materials, a SCDW along such pseudo-1D ODWs provides a natural explanation of our data. Importantly, x-ray-diffraction data eliminate heating and melting of charge order as tenable alternative explanations of our data.« less

  5. Yes, it turns: experimental evidence of pearl rotation during its formation.

    PubMed

    Gueguen, Yannick; Czorlich, Yann; Mastail, Max; Le Tohic, Bruno; Defay, Didier; Lyonnard, Pierre; Marigliano, Damien; Gauthier, Jean-Pierre; Bari, Hubert; Lo, Cedrik; Chabrier, Sébastien; Le Moullac, Gilles

    2015-07-01

    Cultured pearls are human creations formed by inserting a nucleus and a small piece of mantle tissue into a living shelled mollusc, usually a pearl oyster. Although many pearl observations intuitively suggest a possible rotation of the nucleated pearl inside the oyster, no experimental demonstration of such a movement has ever been done. This can be explained by the difficulty of observation of such a phenomenon in the tissues of a living animal. To investigate this question of pearl rotation, a magnetometer system was specifically engineered to register magnetic field variations with magnetic sensors from movements of a magnetic nucleus inserted in the pearl oyster. We demonstrated that a continuous movement of the nucleus inside the oyster starts after a minimum of 40 days post-grafting and continues until the pearl harvest. We measured a mean angular speed of 1.27° min(-1) calculated for four different oysters. Rotation variability was observed among oysters and may be correlated to pearl shape and defects. Nature's ability to generate so amazingly complex structures like a pearl has delivered one of its secrets.

  6. Adaptation of an evidence-based intervention to promote colorectal cancer screening: a quasi-experimental study

    PubMed Central

    2014-01-01

    Background To accelerate the translation of research findings into practice for underserved populations, we investigated the adaptation of an evidence-based intervention (EBI), designed to increase colorectal cancer (CRC) screening in one limited English-proficient (LEP) population (Chinese), for another LEP group (Vietnamese) with overlapping cultural and health beliefs. Methods Guided by Diffusion of Innovations Theory, we adapted the EBI to achieve greater reach. Core elements of the adapted intervention included: small media (a DVD and pamphlet) translated into Vietnamese from Chinese; medical assistants distributing the small media instead of a health educator; and presentations on CRC screening to the medical assistants. A quasi-experimental study examined CRC screening adherence among eligible Vietnamese patients at the intervention and control clinics, before and after the 24-month intervention. The proportion of the adherence was assessed using generalized linear mixed models that account for clustering under primary care providers and also within-patient correlation between baseline and follow up. Results Our study included two cross-sectional samples: 1,016 at baseline (604 in the intervention clinic and 412 in the control clinic) and 1,260 post-intervention (746 in the intervention and 514 in the control clinic), including appreciable overlaps between the two time points. Pre-post change in CRC screening over time, expressed as an odds ratio (OR) of CRC screening adherence by time, showed a marginally-significant greater increase in CRC screening adherence at the intervention clinic compared to the control clinic (the ratio of the two ORs = 1.42; 95% CI 0.95, 2.15). In the sample of patients who were non-adherent to CRC screening at baseline, compared to the control clinic, the intervention clinic had marginally-significant greater increase in FOBT (adjusted OR = 1.77; 95% CI 0.98, 3.18) and a statistically-significantly greater increase in CRC

  7. EVIDENCE FOR EFFECTS OF CHRONIC LEAD EXPOSURE ON BLOOD PRESSURE IN EXPERIMENTAL ANIMALS: AN OVERVIEW

    EPA Science Inventory

    Information obtained in a number of experimental studies conducted over the last forty years on the effects of lead on blood pressure is reviewed. Differences in animal species, age at beginning of exposure, level of lead exposure, indices of lead burden, and blood pressure effec...

  8. Neuroendocrine mechanisms of development of experimental hyperandrogen-induced anovulation.

    PubMed

    Reznikov, A G; Sinitsyn, P V; Tarasenko, L V; Polyakova, L I

    2003-10-01

    An experimental model of hyperandrogen-induced anovulatory infertility (s.c. implantation of Silastic capsules containing testosterone into adult female rats) was used to study morphological, hormonal, and biochemical measures characterizing the state of the hypothalamo-hypophyseal-ovarian system. Impairments in functional androgen metabolism in the hypothalamus were seen, with decreases in the Luliberin sensitivity of the hypophysis, changes in the structure of estral cycles, and morphological changes in the ovaries; these findings are evidence for neuroendocrine disturbances in the control of ovulation. Flutamide, an experimental antiandrogen, led to partial normalization of the hormonal, biochemical, and morphological characteristics, as well as to recovery of fertility in females with anovulatory infertility.

  9. A Rare Case of Cerebellar Ataxia Due to Voltage-Gated Calcium Channel and Glutamic Acid Decarboxylase Autoantibodies.

    PubMed

    Annunziata, Giuseppe; Lobo, Pamela; Carbuccia, Cristian

    2017-11-27

    BACKGROUND Autoimmune cerebellar ataxia can be paraneoplastic in nature or can occasionally present without evidence of an ongoing malignancy. The detection of specific autoantibodies has been statistically linked to different etiologies. CASE REPORT A 55-year-old African-American woman with hypertension and a past history of morbid obesity and uncontrolled diabetes status post gastric bypass four years prior to the visit (with significantly improved body mass index and hemoglobin A1c controlled at the time of the clinical encounter) presented to the office complaining of gradual onset of unsteadiness and recurrent falls for the past three years, as well as difficulties coordinating routine daily activities. The neurologic exam showed moderate dysarthria and ataxic gait with bilateral dysmetria and positive Romberg test. Routine laboratory test results were only remarkable for a mild elevation of erythrocyte sedimentation rate, and most laboratory and imaging tests for common causes of ataxia failed to demonstrate an etiology. Upon further workup, evidence of anti-voltage-gated calcium channel and anti-glutamic acid decarboxylase antibody was demonstrated. She was then treated with intravenous immunoglobulins with remarkable clinical improvement. CONCLUSIONS We present a case of antibody-mediated ataxia not associated with malignancy. While ataxia is rarely related to autoantibodies, in such cases it is critical to understand the etiology of this disabling condition in order to treat it correctly. Clinicians should be aware of the possible association with specific autoantibodies and the necessity to rule out an occult malignancy in such cases.

  10. Differential Activities of the Two Closely Related Withanolides, Withaferin A and Withanone: Bioinformatics and Experimental Evidences

    PubMed Central

    Manjunath, Kavyashree; Uthayakumar, M.; Kanaujia, Shankar P.; Kaul, Sunil C.; Sekar, Kanagaraj; Wadhwa, Renu

    2012-01-01

    Background and Purpose Withanolides are naturally occurring chemical compounds. They are secondary metabolites produced via oxidation of steroids and structurally consist of a steroid-backbone bound to a lactone or its derivatives. They are known to protect plants against herbivores and have medicinal value including anti-inflammation, anti-cancer, adaptogenic and anti-oxidant effects. Withaferin A (Wi-A) and Withanone (Wi-N) are two structurally similar withanolides isolated from Withania somnifera, also known as Ashwagandha in Indian Ayurvedic medicine. Ashwagandha alcoholic leaf extract (i-Extract), rich in Wi-N, was shown to kill cancer cells selectively. Furthermore, the two closely related purified phytochemicals, Wi-A and Wi-N, showed differential activity in normal and cancer human cells in vitro and in vivo. We had earlier identified several genes involved in cytotoxicity of i-Extract in human cancer cells by loss-of-function assays using either siRNA or randomized ribozyme library. Methodology/Principal Findings In the present study, we have employed bioinformatics tools on four genes, i.e., mortalin, p53, p21 and Nrf2, identified by loss-of-function screenings. We examined the docking efficacy of Wi-N and Wi-A to each of the four targets and found that the two closely related phytochemicals have differential binding properties to the selected cellular targets that can potentially instigate differential molecular effects. We validated these findings by undertaking parallel experiments on specific gene responses to either Wi-N or Wi-A in human normal and cancer cells. We demonstrate that Wi-A that binds strongly to the selected targets acts as a strong cytotoxic agent both for normal and cancer cells. Wi-N, on the other hand, has a weak binding to the targets; it showed milder cytotoxicity towards cancer cells and was safe for normal cells. The present molecular docking analyses and experimental evidence revealed important insights to the use of Wi-A and

  11. Experimental evidences of a large extrinsic spin Hall effect in AuW alloy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Laczkowski, P.; Rojas-Sánchez, J.-C.; INAC/SP2M, CEA-Université Joseph Fourier, F-38054 Grenoble

    2014-04-07

    We report an experimental study of a gold-tungsten alloy (7 at. % W concentration in Au host) displaying remarkable properties for spintronics applications using both magneto-transport in lateral spin valve devices and spin-pumping with inverse spin Hall effect experiments. A very large spin Hall angle of about 10% is consistently found using both techniques with the reliable spin diffusion length of 2 nm estimated by the spin sink experiments in the lateral spin valves. With its chemical stability, high resistivity, and small induced damping, this AuW alloy may find applications in the nearest future.

  12. The Effects of Evidence Bounds on Decision-Making: Theoretical and Empirical Developments

    PubMed Central

    Zhang, Jiaxiang

    2012-01-01

    Converging findings from behavioral, neurophysiological, and neuroimaging studies suggest an integration-to-boundary mechanism governing decision formation and choice selection. This mechanism is supported by sequential sampling models of choice decisions, which can implement statistically optimal decision strategies for selecting between multiple alternative options on the basis of sensory evidence. This review focuses on recent developments in understanding the evidence boundary, an important component of decision-making raised by experimental findings and models. The article starts by reviewing the neurobiology of perceptual decisions and several influential sequential sampling models, in particular the drift-diffusion model, the Ornstein–Uhlenbeck model and the leaky-competing-accumulator model. In the second part, the article examines how the boundary may affect a model’s dynamics and performance and to what extent it may improve a model’s fits to experimental data. In the third part, the article examines recent findings that support the presence and site of boundaries in the brain. The article considers two questions: (1) whether the boundary is a spontaneous property of neural integrators, or is controlled by dedicated neural circuits; (2) if the boundary is variable, what could be the driving factors behind boundary changes? The review brings together studies using different experimental methods in seeking answers to these questions, highlights psychological and physiological factors that may be associated with the boundary and its changes, and further considers the evidence boundary as a generic mechanism to guide complex behavior. PMID:22870070

  13. Improving implementation of evidence-based practice in mental health service delivery: protocol for a cluster randomised quasi-experimental investigation of staff-focused values interventions

    PubMed Central

    2013-01-01

    Background There is growing acceptance that optimal service provision for individuals with severe and recurrent mental illness requires a complementary focus on medical recovery (i.e., symptom management and general functioning) and personal recovery (i.e., having a ‘life worth living’). Despite significant research attention and policy-level support, the translation of this vision of healthcare into changed workplace practice continues to elude. Over the past decade, evidence-based training interventions that seek to enhance the knowledge, attitudes, and skills of staff working in the mental health field have been implemented as a primary redress strategy. However, a large body of multi-disciplinary research indicates disappointing rates of training transfer. There is an absence of empirical research that investigates the importance of worker-motivation in the uptake of desired workplace change initiatives. ‘Autonomy’ is acknowledged as important to human effectiveness and as a correlate of workplace variables like productivity, and wellbeing. To our knowledge, there have been no studies that investigate purposeful and structured use of values-based interventions to facilitate increased autonomy as a means of promoting enhanced implementation of workplace change. Methods This study involves 200 mental health workers across 22 worksites within five community-managed organisations in three Australian states. It involves cluster-randomisation of participants within organisation, by work site, to the experimental (values) condition, or the control (implementation). Both conditions receive two days of training focusing on an evidence-based framework of mental health service delivery. The experimental group receives a third day of values-focused intervention and 12 months of values-focused coaching. Well-validated self-report measures are used to explore variables related to values concordance, autonomy, and self-reported implementation success. Audits of work

  14. Comparing the Effectiveness of Public and Private Schools: A Review of Evidence and Interpretations. Occasional Paper.

    ERIC Educational Resources Information Center

    McEwan, Patrick J.

    This paper explores two questions: (1) Do private schools produce greater academic achievement or attainment than public schools? and (2) Does this evidence provide guidance on the potential impact of voucher plans? Based on recent experimental evidence, it finds that Catholic elementary schools have modest effects on the mathematics achievement…

  15. The experimenters' regress reconsidered: Replication, tacit knowledge, and the dynamics of knowledge generation.

    PubMed

    Feest, Uljana

    2016-08-01

    This paper revisits the debate between Harry Collins and Allan Franklin, concerning the experimenters' regress. Focusing my attention on a case study from recent psychology (regarding experimental evidence for the existence of a Mozart Effect), I argue that Franklin is right to highlight the role of epistemological strategies in scientific practice, but that his account does not sufficiently appreciate Collins's point about the importance of tacit knowledge in experimental practice. In turn, Collins rightly highlights the epistemic uncertainty (and skepticism) surrounding much experimental research. However, I will argue that his analysis of tacit knowledge fails to elucidate the reasons why scientists often are (and should be) skeptical of other researchers' experimental results. I will present an analysis of tacit knowledge in experimental research that not only answers to this desideratum, but also shows how such skepticism can in fact be a vital enabling factor for the dynamic processes of experimental knowledge generation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Combining Randomized and Non-Randomized Evidence in Clinical Research: A Review of Methods and Applications

    ERIC Educational Resources Information Center

    Verde, Pablo E.; Ohmann, Christian

    2015-01-01

    Researchers may have multiple motivations for combining disparate pieces of evidence in a meta-analysis, such as generalizing experimental results or increasing the power to detect an effect that a single study is not able to detect. However, while in meta-analysis, the main question may be simple, the structure of evidence available to answer it…

  17. Strain rate sensitivity of the tensile strength of two silicon carbides: experimental evidence and micromechanical modelling

    NASA Astrophysics Data System (ADS)

    Zinszner, Jean-Luc; Erzar, Benjamin; Forquin, Pascal

    2017-01-01

    Ceramic materials are commonly used to design multi-layer armour systems thanks to their favourable physical and mechanical properties. However, during an impact event, fragmentation of the ceramic plate inevitably occurs due to its inherent brittleness under tensile loading. Consequently, an accurate model of the fragmentation process is necessary in order to achieve an optimum design for a desired armour configuration. In this work, shockless spalling tests have been performed on two silicon carbide grades at strain rates ranging from 103 to 104 s-1 using a high-pulsed power generator. These spalling tests characterize the tensile strength strain rate sensitivity of each ceramic grade. The microstructural properties of the ceramics appear to play an important role on the strain rate sensitivity and on the dynamic tensile strength. Moreover, this experimental configuration allows for recovering damaged, but unbroken specimens, giving unique insight on the fragmentation process initiated in the ceramics. All the collected data have been compared with corresponding results of numerical simulations performed using the Denoual-Forquin-Hild anisotropic damage model. Good agreement is observed between numerical simulations and experimental data in terms of free surface velocity, size and location of the damaged zones along with crack density in these damaged zones. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  18. Strain rate sensitivity of the tensile strength of two silicon carbides: experimental evidence and micromechanical modelling.

    PubMed

    Zinszner, Jean-Luc; Erzar, Benjamin; Forquin, Pascal

    2017-01-28

    Ceramic materials are commonly used to design multi-layer armour systems thanks to their favourable physical and mechanical properties. However, during an impact event, fragmentation of the ceramic plate inevitably occurs due to its inherent brittleness under tensile loading. Consequently, an accurate model of the fragmentation process is necessary in order to achieve an optimum design for a desired armour configuration. In this work, shockless spalling tests have been performed on two silicon carbide grades at strain rates ranging from 10 3 to 10 4  s -1 using a high-pulsed power generator. These spalling tests characterize the tensile strength strain rate sensitivity of each ceramic grade. The microstructural properties of the ceramics appear to play an important role on the strain rate sensitivity and on the dynamic tensile strength. Moreover, this experimental configuration allows for recovering damaged, but unbroken specimens, giving unique insight on the fragmentation process initiated in the ceramics. All the collected data have been compared with corresponding results of numerical simulations performed using the Denoual-Forquin-Hild anisotropic damage model. Good agreement is observed between numerical simulations and experimental data in terms of free surface velocity, size and location of the damaged zones along with crack density in these damaged zones.This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'. © 2016 The Author(s).

  19. Strain rate sensitivity of the tensile strength of two silicon carbides: experimental evidence and micromechanical modelling

    PubMed Central

    Erzar, Benjamin

    2017-01-01

    Ceramic materials are commonly used to design multi-layer armour systems thanks to their favourable physical and mechanical properties. However, during an impact event, fragmentation of the ceramic plate inevitably occurs due to its inherent brittleness under tensile loading. Consequently, an accurate model of the fragmentation process is necessary in order to achieve an optimum design for a desired armour configuration. In this work, shockless spalling tests have been performed on two silicon carbide grades at strain rates ranging from 103 to 104 s−1 using a high-pulsed power generator. These spalling tests characterize the tensile strength strain rate sensitivity of each ceramic grade. The microstructural properties of the ceramics appear to play an important role on the strain rate sensitivity and on the dynamic tensile strength. Moreover, this experimental configuration allows for recovering damaged, but unbroken specimens, giving unique insight on the fragmentation process initiated in the ceramics. All the collected data have been compared with corresponding results of numerical simulations performed using the Denoual–Forquin–Hild anisotropic damage model. Good agreement is observed between numerical simulations and experimental data in terms of free surface velocity, size and location of the damaged zones along with crack density in these damaged zones. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’. PMID:27956504

  20. Yes, it turns: experimental evidence of pearl rotation during its formation

    PubMed Central

    Gueguen, Yannick; Czorlich, Yann; Mastail, Max; Le Tohic, Bruno; Defay, Didier; Lyonnard, Pierre; Marigliano, Damien; Gauthier, Jean-Pierre; Bari, Hubert; Lo, Cedrik; Chabrier, Sébastien; Le Moullac, Gilles

    2015-01-01

    Cultured pearls are human creations formed by inserting a nucleus and a small piece of mantle tissue into a living shelled mollusc, usually a pearl oyster. Although many pearl observations intuitively suggest a possible rotation of the nucleated pearl inside the oyster, no experimental demonstration of such a movement has ever been done. This can be explained by the difficulty of observation of such a phenomenon in the tissues of a living animal. To investigate this question of pearl rotation, a magnetometer system was specifically engineered to register magnetic field variations with magnetic sensors from movements of a magnetic nucleus inserted in the pearl oyster. We demonstrated that a continuous movement of the nucleus inside the oyster starts after a minimum of 40 days post-grafting and continues until the pearl harvest. We measured a mean angular speed of 1.27° min−1 calculated for four different oysters. Rotation variability was observed among oysters and may be correlated to pearl shape and defects. Nature's ability to generate so amazingly complex structures like a pearl has delivered one of its secrets. PMID:26587271

  1. Quasi-Experimental Evidence of Peer Effects in First-Year Economics Courses at a Chinese University

    ERIC Educational Resources Information Center

    Chen, Qihui; Tian, Guoqiang; Okediji, Tade O.

    2014-01-01

    The authors of this article implement a quasi-experimental strategy to estimate peer effects in economic education by exploiting the institutional setting in a large public university in China, where roommates are randomly assigned conditional on a student's major and province of origin. They found significant impacts of peer academic quality,…

  2. Distant Healing Intention Therapies: An Overview of the Scientific Evidence

    PubMed Central

    Schlitz, Marilyn; Baur, Christopher

    2015-01-01

    This article provides a broad overview of “distant healing intention” (DHI) therapies, ie, intentional healing modalities claimed to transcend the usual constraints of distance through space or time. We provide a summary of previous reviews and meta-analyses that have explored a diverse array of DHI modalities, outcome measures, and experimental protocols. While some significant experimental effects have been observed, the evidence to date does not yet provide confidence in its clinical efficacy. The purported “nonlocal” nature of DHI raises significant methodological and theoretical challenges. We recommend several avenues for improving future research. PMID:26665044

  3. Individual benefits of nestling begging: experimental evidence for an immediate effect, but no evidence for a delayed effect.

    PubMed

    Lessells, C Kate M; Riebel, Katharina; Draganoiu, Tudor Ion

    2011-06-23

    The evolutionary stability of honest signalling by offspring is thought to require that begging displays be costly, so the costs and benefits of begging--and whether they are experienced individually or by the whole brood--are crucial to understanding the evolution of begging behaviour. Begging is known to have immediate individual benefits (parents distribute more food to intensely begging individuals) and delayed brood benefits (parents increase provisioning rate to the brood), but the possibility of delayed individual benefits (previous begging affects the current distribution of food) has rarely, if ever, been researched. We did this using playback of great tit Parus major chick begging and a control sound from either side of the nest. Male parents fed chicks close to the speaker more when great tit chick begging, but not other stimuli, was played back. In contrast, there was no effect of playback at the previous visit on the chicks that male parents fed. We have thus demonstrated an immediate individual benefit to begging, but found no evidence of a delayed individual benefit in this species.

  4. The effect of integrating constructivist and evidence-based practice on baccalaureate nursing student's cognitive load and learning performance in a research course.

    PubMed

    Hsieh, Suh-Ing; Hsu, Li-Ling; Huang, Tzu-Hsin

    2016-07-01

    Baccalaureate nursing students perceive research as unattractive, doubt the value of nursing research, and do not appreciate the link of research with practice. No studies have examined students' cognitive load during an evidence-based practice research course versus a traditional research course. To assess the effect of integrating constructivist theories and evidence-based practice on student cognitive load and learning performance in a research course. A true experimental study. A Registered Nurse-to-Bachelor of Science in Nursing program. Six classes of second-year students. Students were randomly allocated to the control group (two classes) or the experimental group (two classes) using cluster randomization. The control group underwent "traditional research"; the experimental group experienced "integrating evidence-based practice into research." Instruments for outcome assessment include the Cognitive Load Scale, cognitive test, team critique paper, and qualitative feedback on course satisfaction. The between-subjects effects were compared by Analysis of Covariance. The experimental group had significantly higher mental load (8.74 vs. 7.27, p<.001), mental effort (11.07 vs. 10.07, p=.009), mental efficiency (0.33 vs. -0.31, p<.001), and research knowledge (70.61 vs. 44.92, p<.001) than the control group. The experimental group had better critique paper scores in introduction (92.80%), literature review (91.70%), and assignment requirement and writing (89.40%). Some experimental learners expressed satisfaction with learning evidence-based practice (17.78%) and critiquing a research article (7.78%). Integrating evidence-based practice into a research course not only improved the research knowledge of baccalaureate nursing students, but also increased their mental load, mental effort, and mental efficiency. Additional studies may track learners' responses to different learning systems using the developed instrument to measure the three types of cognitive load

  5. The emergence of modern statistics in agricultural science: analysis of variance, experimental design and the reshaping of research at Rothamsted Experimental Station, 1919-1933.

    PubMed

    Parolini, Giuditta

    2015-01-01

    During the twentieth century statistical methods have transformed research in the experimental and social sciences. Qualitative evidence has largely been replaced by quantitative results and the tools of statistical inference have helped foster a new ideal of objectivity in scientific knowledge. The paper will investigate this transformation by considering the genesis of analysis of variance and experimental design, statistical methods nowadays taught in every elementary course of statistics for the experimental and social sciences. These methods were developed by the mathematician and geneticist R. A. Fisher during the 1920s, while he was working at Rothamsted Experimental Station, where agricultural research was in turn reshaped by Fisher's methods. Analysis of variance and experimental design required new practices and instruments in field and laboratory research, and imposed a redistribution of expertise among statisticians, experimental scientists and the farm staff. On the other hand the use of statistical methods in agricultural science called for a systematization of information management and made computing an activity integral to the experimental research done at Rothamsted, permanently integrating the statisticians' tools and expertise into the station research programme. Fisher's statistical methods did not remain confined within agricultural research and by the end of the 1950s they had come to stay in psychology, sociology, education, chemistry, medicine, engineering, economics, quality control, just to mention a few of the disciplines which adopted them.

  6. EXTRAHEPATIC TOXICITY OF ACETAMINOPHEN: CRITICAL EVALUATION OF THE EVIDENCE AND PROPOSED MECHANISMS

    PubMed Central

    Kennon-McGill, Stefanie; McGill, Mitchell R.

    2017-01-01

    Research on acetaminophen (APAP) toxicity over the last several decades has focused on the pathophysiology of liver injury, but increasing attention is being paid to other known and possible adverse effects. It has been known for decades that APAP causes acute kidney injury, but confusion exists regarding prevalence, and the mechanisms have not been well investigated. More recently, a number of experimental, clinical and epidemiological studies have reported evidence for pulmonary, endocrine, neurological and neurodevelopmental toxicity, but the quality of evidence from those studies varies. It is important to consider these data due to implications for regulation and clinical practice. Here, we review the evidence and proposed mechanisms for extrahepatic adverse effects of APAP and weigh weaknesses and strengths in the data. We consider results from clinical, epidemiological and experimental research. Our goal is to determine the strength of claims regarding extrahepatic toxicity of APAP and to identify areas of need for future research. It is especially important to view claims of developmental effects of antenatal APAP exposure with a critical eye because APAP is currently the only over-the-counter medication recommended for pregnant women to self-treat pain and fever. PMID:29457141

  7. Quasi-experimental study designs series-paper 1: introduction: two historical lineages.

    PubMed

    Bärnighausen, Till; Røttingen, John-Arne; Rockers, Peter; Shemilt, Ian; Tugwell, Peter

    2017-09-01

    The objective of this study was to contrast the historical development of experiments and quasi-experiments and provide the motivation for a journal series on quasi-experimental designs in health research. A short historical narrative, with concrete examples, and arguments based on an understanding of the practice of health research and evidence synthesis. Health research has played a key role in developing today's gold standard for causal inference-the randomized controlled multiply blinded trial. Historically, allocation approaches developed from convenience and purposive allocation to alternate and, finally, to random allocation. This development was motivated both by concerns for manipulation in allocation as well as statistical and theoretical developments demonstrating the power of randomization in creating counterfactuals for causal inference. In contrast to the sequential development of experiments, quasi-experiments originated at very different points in time, from very different scientific perspectives, and with frequent and long interruptions in their methodological development. Health researchers have only recently started to recognize the value of quasi-experiments for generating novel insights on causal relationships. While quasi-experiments are unlikely to replace experiments in generating the efficacy and safety evidence required for clinical guidelines and regulatory approval of medical technologies, quasi-experiments can play an important role in establishing the effectiveness of health care practice, programs, and policies. The papers in this series describe and discuss a range of important issues in utilizing quasi-experimental designs for primary research and quasi-experimental results for evidence synthesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Inertial vestibular coding of motion: concepts and evidence

    NASA Technical Reports Server (NTRS)

    Hess, B. J.; Angelaki, D. E.

    1997-01-01

    Central processing of inertial sensory information about head attitude and motion in space is crucial for motor control. Vestibular signals are coded relative to a non-inertial system, the head, that is virtually continuously in motion. Evidence for transformation of vestibular signals from head-fixed sensory coordinates to gravity-centered coordinates have been provided by studies of the vestibulo-ocular reflex. The underlying central processing depends on otolith afferent information that needs to be resolved in terms of head translation related inertial forces and head attitude dependent pull of gravity. Theoretical solutions have been suggested, but experimental evidence is still scarce. It appears, along these lines, that gaze control systems are intimately linked to motor control of head attitude and posture.

  9. Mimicking aphasic semantic errors in normal speech production: evidence from a novel experimental paradigm.

    PubMed

    Hodgson, Catherine; Lambon Ralph, Matthew A

    2008-01-01

    Semantic errors are commonly found in semantic dementia (SD) and some forms of stroke aphasia and provide insights into semantic processing and speech production. Low error rates are found in standard picture naming tasks in normal controls. In order to increase error rates and thus provide an experimental model of aphasic performance, this study utilised a novel method- tempo picture naming. Experiment 1 showed that, compared to standard deadline naming tasks, participants made more errors on the tempo picture naming tasks. Further, RTs were longer and more errors were produced to living items than non-living items a pattern seen in both semantic dementia and semantically-impaired stroke aphasic patients. Experiment 2 showed that providing the initial phoneme as a cue enhanced performance whereas providing an incorrect phonemic cue further reduced performance. These results support the contention that the tempo picture naming paradigm reduces the time allowed for controlled semantic processing causing increased error rates. This experimental procedure would, therefore, appear to mimic the performance of aphasic patients with multi-modal semantic impairment that results from poor semantic control rather than the degradation of semantic representations observed in semantic dementia [Jefferies, E. A., & Lambon Ralph, M. A. (2006). Semantic impairment in stoke aphasia vs. semantic dementia: A case-series comparison. Brain, 129, 2132-2147]. Further implications for theories of semantic cognition and models of speech processing are discussed.

  10. The continuum of monocyte phenotypes: Experimental evidence and prognostic utility in assessing cardiovascular risk.

    PubMed

    Cignarella, Andrea; Tedesco, Serena; Cappellari, Roberta; Fadini, Gian Paolo

    2018-03-30

    The monocyte-macrophage cell lineage represents a major player in innate immunity, and is involved in many physiologic and pathologic conditions. Particularly, monocyte-macrophages play a very important role in atherosclerosis and cardiovascular disease. Monocyte heterogeneity is well recognized but the biologic and clinical meaning of the various monocyte subtypes is not entirely understood. Traditionally, monocytes can be divided in classical, intermediate, and nonclassical based on expression of the surface antigens CD14 and CD16. While macrophage diversity is now well recognized to organize as a continuum, monocyte subsets have long been considered as separated entities. However, mounting evidence obtained by tracking the ontology of human monocytes help clarifying that monocytes mature from classical to nonclassical ones, through an intermediate phenotype. This concept is therefore best depicted as a continuum, whereas the subdivision into discrete CD14/CD16 subsets appears an oversimplification. In this review, we discuss the evidence supporting the existence of a monocyte continuum along with the technical challenges of monocyte characterization. In particular, we describe the advantage of considering monocytes along a continuous distribution for the evaluation of cardiovascular risk. We make the point that small transition along the monocyte continuum better reflects cardiovascular risk than a simplified analysis of discrete monocyte subsets. Recognizing the monocyte continuum can be helpful to model other pathophysiologic conditions where these cells are involved. ©2018 Society for Leukocyte Biology.

  11. Evidence That Counts: 12 Teacher-Led Randomised Controlled Trials and Other Styles of Experimental Research

    ERIC Educational Resources Information Center

    Churches, Richard; McAleavy, Tony

    2016-01-01

    This publication contains 12 (A3 open-out) poster-style reports of teacher experimental research. The style of presentation parallels the type of preliminary reporting common at academic conferences and postgraduate events. At the same time, it aims to act as a form of short primer to introduce teachers to the basic options that there are when…

  12. Conscious and Nonconscious Processes:Distinct Forms of Evidence Accumulation?

    NASA Astrophysics Data System (ADS)

    Dehaene, Stanislas

    Among the many brain events evoked by a visual stimulus, which ones are associated specifically with conscious perception, and which merely reflect nonconscious processing? Understanding the neuronal mechanisms of consciousness is a major challenge for cognitive neuroscience. Recently, progress has been achieved by contrasting behavior and brain activation in minimally different experimental conditions, one of which leads to conscious perception whereas the other does not. This chapter reviews briefly this line of research and speculates on its theoretical interpretation. I propose to draw links between evidence accumulation models, which are highly successful in capturing elementary psychophysical decisions, and the conscious/nonconscious dichotomy. In this framework, conscious access would correspond to the crossing of a threshold in evidence accumulation within a distributed global workspace, a set of recurrently connected neurons with long axons that is able to integrate and broadcast back evidence from multiple brain processors. During nonconscious processing, evidence would be accumulated locally within specialized subcircuits, but would fail to reach the threshold needed for global ignition and, therefore, conscious reportability.

  13. The role of "evidence" in recovery from mental illness.

    PubMed

    Tanenbaum, Sandra J

    2006-12-01

    Evidence-based practice (EBP), a derivative of evidence-based medicine (EBM), is ascendant in the United States' mental health system; the findings of randomized controlled trials and other experimental research are widely considered authoritative in mental health practice and policy. The concept of recovery from mental illness is similarly pervasive in mental health programming and advocacy, and it emphasizes consumer expertise and self-determination. What is the relationship between these two powerful and potentially incompatible forces for mental health reform? This paper identifies four attempts, in the mental health literature, to delineate the role of "evidence" in recovery. One is the strong version of evidence-based practice-an applied science model-and three others address weaknesses in the first by limiting the authority of probabilistic findings. The paper also offers a fifth version, based on the concept of communicative accountability, which is derived from Habermas' work on communicative action. The fifth version responds to the other four and emphasizes learning, disclosure and respect in clinical and other helping relationships.

  14. How Do Ability Peer Effects Operate? Evidence on One Transmission Channel

    ERIC Educational Resources Information Center

    Kiss, David

    2018-01-01

    Many (quasi-)experimental studies show that students tend to learn more in classes with better peers. However, the (presumably numerous) factors mediating the positive relationship between peer and own achievement have received less attention in the literature. I present evidence on one particular transmission channel: teachers tend to grade…

  15. Classroom Simulation to Prepare Teachers to Use Evidence-Based Comprehension Practices

    ERIC Educational Resources Information Center

    Ely, Emily; Alves, Kat D.; Dolenc, Nathan R.; Sebolt, Stephanie; Walton, Emily A.

    2018-01-01

    Reading comprehension is an area of weakness for many students, including those with disabilities. Innovative technology methods may play a role in improving teacher readiness to use evidence-based comprehension practices for all students. In this experimental study, researchers examined a classroom simulation (TLE TeachLivE™) to improve…

  16. [Is it possible a bioethics based on the experimental evidence?].

    PubMed

    Pastor, Luis Miguel

    2013-01-01

    For years there are different types of criticism about principialist bioethics. One alternative that has been proposed is to introduce empirical evidence within the bioethical discourse to make it less formal, less theoretical and closer to reality. In this paper we analyze first in synthetic form diverse alternative proposals to make an empirical bioethics. Some of them are strongly naturalistic while others aim to provide empirical data only for correct or improve bioethical work. Most of them are not shown in favor of maintaining a complete separation between facts and values, between what is and what ought to be. With different nuances these proposals of moderate naturalism make ethical judgments depend normative social opinion resulting into a certain social naturalism. Against these proposals we think to make a bioethics in that relates the empirical facts with ethical duties, we must rediscover empirical reality of human action. Only from it and, in particular, from the activity of discernment that makes practical reason, when judged on the object of his action, it is possible to integrate the mere descriptive facts with ethical judgments of character prescriptive. In conclusion we think that it is not possible to perform bioethics a mode of empirical science, as this would be contrary to natural reason, leading to a sort of scientific reductionism. At the same time we believe that empirical data are important in the development of bioethics and to enhance and improve the innate ability of human reason to discern good. From this discernment could develop a bioethics from the perspective of ethical agents themselves, avoiding the extremes of an excessive normative rationalism, accepting empirical data and not falling into a simple pragmatism.

  17. Thermomechanical simulations and experimental validation for high speed incremental forming

    NASA Astrophysics Data System (ADS)

    Ambrogio, Giuseppina; Gagliardi, Francesco; Filice, Luigino; Romero, Natalia

    2016-10-01

    Incremental sheet forming (ISF) consists in deforming only a small region of the workspace through a punch driven by a NC machine. The drawback of this process is its slowness. In this study, a high speed variant has been investigated from both numerical and experimental points of view. The aim has been the design of a FEM model able to perform the material behavior during the high speed process by defining a thermomechanical model. An experimental campaign has been performed by a CNC lathe with high speed to test process feasibility. The first results have shown how the material presents the same performance than in conventional speed ISF and, in some cases, better material behavior due to the temperature increment. An accurate numerical simulation has been performed to investigate the material behavior during the high speed process confirming substantially experimental evidence.

  18. Experimental animal studies of radon and cigarette smoke

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cross, F.T.; Dagle, G.E.; Gies, R.A.

    Cigarette-smoking is a dominant cause of lung cancer and confounds risk assessment of exposure to radon decay products. Evidence in humans on the interaction between cigarette-smoking and exposure to radon decay products, although limited, indicates a possible synergy. Experimental animal data, in addition to showing synergy, also show a decrease or no change in risk with added cigarette-smoke exposures. This article reviews previous animal data developed at Compagnie Generale des Matieres Nucleaires and Pacific Northwest Laboratory (PNL) on mixed exposures to radon and cigarette smoke, and highlights new initiation-promotion-initiation (IPI) studies at PNL that were designed within the framework ofmore » a two-mutation carcinogenesis model. Also presented are the PNL exposure system, experimental protocols, dosimetry, and biological data observed to date in IPI animals.« less

  19. The rights of man and animal experimentation.

    PubMed Central

    Martin, J

    1990-01-01

    Since emotions give contradictory signals about animal experimentation in medical science, man's relationship to animals must be based upon reason. Thomas Aquinas argues that man is essentially different from animals because man's intellectual processes show evidence of an abstract mechanism not possessed by animals. Man's rights arise in association with this essential difference. The consequence is that only man possesses true rights by Aquinas's definition; animals have them only by analogy. However, cruelty to animals is illicit and they should be protected, principally not because they have rights, but because he who is cruel to animals is more likely to be cruel to his fellowman. If there is a need for animal experimentation in science for the good of man, this approach gives philosophical justification for experimentation, since man's well-being must come before that of animals because of his unique possession of rights. However, those experiments should be carried out in the kindest way possible, to promote kindness towards man. To see man as solely part of a biological continuum in competition for rights with those beings close to him biologically, detracts from man's dignity. PMID:2135948

  20. The Navigation Guide—Evidence-Based Medicine Meets Environmental Health: Systematic Review of Nonhuman Evidence for PFOA Effects on Fetal Growth

    PubMed Central

    Lam, Juleen; Sutton, Patrice; Johnson, Paula I.; Atchley, Dylan S.; Sen, Saunak; Robinson, Karen A.; Axelrad, Daniel A.; Woodruff, Tracey J.

    2014-01-01

    Background: In contrast to current methods of expert-based narrative review, the Navigation Guide is a systematic and transparent method for synthesizing environmental health research from multiple evidence streams. The Navigation Guide was developed to effectively and efficiently translate the available scientific evidence into timely prevention-oriented action. Objectives: We applied the Navigation Guide systematic review method to answer the question “Does fetal developmental exposure to perfluorooctanoic acid (PFOA) or its salts affect fetal growth in animals ?” and to rate the strength of the experimental animal evidence. Methods: We conducted a comprehensive search of the literature, applied prespecified criteria to the search results to identify relevant studies, extracted data from studies, obtained additional information from study authors, conducted meta-analyses, and rated the overall quality and strength of the evidence. Results: Twenty-one studies met the inclusion criteria. From the meta-analysis of eight mouse gavage data sets, we estimated that exposure of pregnant mice to increasing concentrations of PFOA was associated with a change in mean pup birth weight of –0.023 g (95% CI: –0.029, –0.016) per 1-unit increase in dose (milligrams per kilogram body weight per day). The evidence, consisting of 15 mammalian and 6 nonmammalian studies, was rated as “moderate” and “low” quality, respectively. Conclusion: Based on this first application of the Navigation Guide methodology, we found sufficient evidence that fetal developmental exposure to PFOA reduces fetal growth in animals. Citation: Koustas E, Lam J, Sutton P, Johnson PI, Atchley DS, Sen S, Robinson KA, Axelrad DA, Woodruff TJ. 2014. The Navigation Guide—evidence-based medicine meets environmental health: systematic review of nonhuman evidence for PFOA effects on fetal growth. Environ Health Perspect 122:1015–1027; http://dx.doi.org/10.1289/ehp.1307177 PMID:24968374

  1. Overconfidence in wargames: experimental evidence on expectations, aggression, gender and testosterone

    PubMed Central

    Johnson, Dominic D.P; McDermott, Rose; Barrett, Emily S; Cowden, Jonathan; Wrangham, Richard; McIntyre, Matthew H; Peter Rosen, Stephen

    2006-01-01

    Summary Overconfidence has long been noted by historians and political scientists as a major cause of war. However, the origins of such overconfidence, and sources of variation, remain poorly understood. Mounting empirical studies now show that mentally healthy people tend to exhibit psychological biases that encourage optimism, collectively known as ‘positive illusions’. Positive illusions are thought to have been adaptive in our evolutionary past because they served to cope with adversity, harden resolve, or bluff opponents. Today, however, positive illusions may contribute to costly conflicts and wars. Testosterone has been proposed as a proximate mediator of positive illusions, given its role in promoting dominance and challenge behaviour, particularly in men. To date, no studies have attempted to link overconfidence, decisions about war, gender, and testosterone. Here we report that, in experimental wargames: (i) people are overconfident about their expectations of success; (ii) those who are more overconfident are more likely to attack; (iii) overconfidence and attacks are more pronounced among males than females; and (iv) testosterone is related to expectations of success, but not within gender, so its influence on overconfidence cannot be distinguished from any other gender specific factor. Overall, these results constitute the first empirical support of recent theoretical work linking overconfidence and war. PMID:16959643

  2. On a magnetic reconnection in the Venusian wake. The experimental evidences.

    NASA Astrophysics Data System (ADS)

    Fedorov, Andrei; Jarvinen, Riku; Volwerk, Martin; Barabash, Stas; Zhang, Tielong; Sauvaud, Jean-Andre

    2010-05-01

    The Venusian magnetotail is formed by solar wind magnetic flux tubes draping around the planet and stretched antisunward. The magnetotail topology represents two magnetic lobes separated by a thin current sheet. Such a configuration is a free energy reservoir. The accumulated energy is generally released by antisunward acceleration of the planetary ions. But in the case of a magnetic reconnection, hypothetically appeared somewhere in the equatorial current sheet, some part of the planetary ions filling the tail, should be accelerated toward the planet. To check this hypothesis we have performed statistical and case studies based on the data from the IMA mass-spectrometer and the magnetometer onboard ESA Venus Express mission. We found that the distribution function of the planetary ions in the equatorial plane of the wake, near the midnight, and at the distances less than 1.7Rv from the center of the planet contains the significant part moving toward the planet. At the same time the magnetic field statistics and the numerical simulation show the magnetic field minimum similar to an X-line in the current sheet at the distance about 1.7 Rv from the planet center. This could be an evidence for a quasi-permanent reconnection in the Venusian wake.

  3. [The experimental surgery and your relation with the university: an experience report].

    PubMed

    Yamaki, Vitor Nagai; Teixeira, Renan Kleber Costa; Feijo, Daniel Haber; Silva, José Antonio Cordero da; Botelho, Nara Macedo; Henriques, Marcus Vinicius

    2014-01-01

    The laboratory of experimental surgery represents one of the key points for the university, especially in the biomedical area. This focuses on the university's tripod of primary structure that are teaching, research and extension, which are essential for formation of humanistic and practice of a good doctor that is based, first of all, on scientific evidence and critical knowledge. The importance of a laboratory of experimental surgery centers for medical education was regulated from the new curriculum guidelines of the Ministério da Educação e Cultura, establishing a mandatory laboratory within college centers. Therefore, it is of great importance to the contribution of the laboratories of experimental surgery in the curriculum, both in the discipline of surgical technics and experimental surgery, and an incentive for basic research. Thus, the study presents the experience of 15 years of the Laboratory of Experimental Surgery from Universidade do Estado do Pará, with the goal show the importance of this to medical graduation and the university.

  4. Experimental evidence of a potentially increased thrombo-embolic disease risk by domestic electromagnetic field exposure.

    PubMed

    Caprani, A; Richert, A; Flaud, P

    2004-05-01

    We have used the EaHy926 endothelial cell line, able to secrete both pro and anti-aggregant platelet agents, as a model for thrombo-embolic diseases. We experimentally established, by comparing these two secretions with or without a Faraday cage, that the environmental electromagnetic field significantly increases the thrombo-embolic risks in this endothelial cell line. Copyright 2004 Wiley-Liss, Inc.

  5. Saccade and cognitive impairment associated with kava intoxication.

    PubMed

    Cairney, Sheree; Maruff, Paul; Clough, Alan R; Collie, Alex; Currie, Jon; Currie, Bart J

    2003-10-01

    Kava is an extract from the Piper methysticum Forst. f. plant that has social and spiritual importance in Pacific islands societies. Herbal remedies that contain kava are used for the psychiatric treatment of anxiety and insomnia. Laboratory studies have found only subtle, if any, changes on cognitive or motor functions from the acute effects of consuming small clinical doses of kava products. Intoxication from recreational doses of kava has not been studied. The performance of individuals intoxicated from drinking kava (n=11) was compared with a control group (n=17) using saccade and cognitive tests. On average, intoxicated individuals had consumed 205 g of kava powder each (approximately 150 times clinical doses) in a group session that went for 14.4 h and ended 8 h prior to testing. Intoxicated kava drinkers showed ataxia, tremors, sedation, blepharospasm and elevated liver enzymes (GGT and ALP), together with saccadic dysmetria, saccadic slowing and reduced accuracy performing a visual search task that only became evident as the task complexity increased. Kava intoxication is characterized by specific abnormalities of movement coordination and visual attention but normal performance of complex cognitive functions. Saccade abnormalities suggest disruption of cerebellar and GABAergic functions. Copyright 2003 John Wiley & Sons, Ltd.

  6. Evidence for consciousness-related anomalies in random physical systems

    NASA Astrophysics Data System (ADS)

    Radin, Dean I.; Nelson, Roger D.

    1989-12-01

    Speculations about the role of consciousness in physical systems are frequently observed in the literature concerned with the interpretation of quantum mechanics. While only three experimental investigations can be found on this topic in physics journals, more than 800 relevant experiments have been reported in the literature of parapsychology. A well-defined body of empirical evidence from this domain was reviewed using meta-analytic techniques to assess methodological quality and overall effect size. Results showed effects conforming to chance expectation in control conditions and unequivocal non-chance effects in experimental conditions. This quantitative literature review agrees with the findings of two earlier reviews, suggesting the existence of some form of consciousness-related anomaly in random physical systems.

  7. Experimental evidence of warming-induced flowering in the Mediterranean seagrass Posidonia oceanica.

    PubMed

    Ruiz, J M; Marín-Guirao, L; García-Muñoz, R; Ramos-Segura, A; Bernardeau-Esteller, J; Pérez, M; Sanmartí, N; Ontoria, Y; Romero, J; Arthur, R; Alcoverro, T; Procaccini, G

    2017-10-25

    Sexual reproduction in predominantly clonal marine plants increases recombination favoring adaptation and enhancing species resilience to environmental change. Recent studies of the seagrass Posidonia oceanica suggest that flowering intensity and frequency are correlated with warming events associated with global climate change, but these studies have been observational without direct experimental support. We used controlled experiments to test if warming can effectively trigger flowering in P. oceanica. A six-week heat wave was simulated under laboratory mesocosm conditions. Heating negatively impacted leaf growth rates, but by the end of the experiment most of the heated plants flowered, while controls plants did not. Heated and control plants were not genetically distinct and flowering intensity was significantly correlated with allelic richness and heterozygosity. This is an unprecedented finding, showing that the response of seagrasses to warming will be more plastic, more complex and potentially more resilient than previously imagined. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Camera perspective bias in videotaped confessions: experimental evidence of its perceptual basis.

    PubMed

    Ratcliff, Jennifer J; Lassiter, G Daniel; Schmidt, Heather C; Snyder, Celeste J

    2006-12-01

    The camera perspective from which a criminal confession is videotaped influences later assessments of its voluntariness and the suspect's guilt. Previous research has suggested that this camera perspective bias is rooted in perceptual rather than conceptual processes, but these data are strictly correlational. In 3 experiments, the authors directly manipulated perceptual processing to provide stronger evidence of its mediational role. Prior to viewing a videotape of a simulated confession, participants were shown a photograph of the confessor's apparent victim. Participants in a perceptual interference condition were instructed to visualize the image of the victim in their minds while viewing the videotape; participants in a conceptual interference condition were instructed instead to rehearse an 8-digit number. Because mental imagery and actual perception draw on the same available resources, the authors anticipated that the former, but not the latter, interference task would disrupt the camera perspective bias, if indeed it were perceptually mediated. Results supported this conclusion.

  9. Experimental evidence of vocal recognition in young and adult black-legged kittiwakes

    USGS Publications Warehouse

    Mulard, Hervé; Aubin, T.; White, J.F.; Hatch, Shyla A.; Danchin, E.

    2008-01-01

    Individual recognition is required in most social interactions, and its presence has been confirmed in many species. In birds, vocal cues appear to be a major component of recognition. Curiously, vocal recognition seems absent or limited in some highly social species such as the black-legged kittiwake, Rissa tridactyla. Using playback experiments, we found that kittiwake chicks recognized their parents vocally, this capacity being detectable as early as 20 days after hatching, the youngest age tested. Mates also recognized each other's long calls. Some birds reacted to their partner's voice when only a part of the long call was played back. Nevertheless, only about a third of the tested birds reacted to their mate's or parents' call and we were unable to detect recognition among neighbours. We discuss the low reactivity of kittiwakes in relation to their cliff-nesting habit and compare our results with evidence of vocal recognition in other larids. ?? 2008 The Association for the Study of Animal Behaviour.

  10. Improving the Effectiveness of Fundraising Messages: The Impact of Charity Goal Attainment, Message Framing, and Evidence on Persuasion

    ERIC Educational Resources Information Center

    Das, Enny; Kerkhof, Peter; Kuiper, Joyce

    2008-01-01

    This experimental study assessed the effectiveness of fundraising messages. Based on recent findings regarding the effects of message framing and evidence, effective fundraising messages should combine abstract, statistical information with a negative message frame and anecdotal evidence with a positive message frame. In addition, building on…

  11. Weighing up the evidence: a systematic review of the effectiveness of workplace interventions to tackle socio-economic inequalities in obesity

    PubMed Central

    Cairns, Joanne-Marie; Bambra, Clare; Hillier-Brown, Frances C.; Moore, Helen J.; Summerbell, Carolyn D.

    2015-01-01

    Abstract Background Addressing socio-economic inequalities in obesity is a public health priority and the workplace is seen as a potential health promotion site. However, there is a lack of evidence on what works. This article systematically reviews studies of the effects of workplace interventions on socio-economic inequalities in obesity. Methods Following PRISMA guidelines, we searched for published or unpublished experimental and observational evaluation studies. Nine electronic databases were searched as well as websites and bibliographies. Included studies were data extracted, quality assessed and narratively synthesized. Results Eighteen studies were included of which 14 examined behavioural interventions and 4 mixed or environmental ones. While most studies (n = 12) found no effects on inequalities in obesity—and a minority found increases (n = 3), there was also some evidence of potentially effective workplace interventions (n = 3) especially in terms of physical activity interventions targeted at lower occupational groups. Conclusion There is experimental evidence that workplace delivered physical activity interventions have the potential to reduce inequalities in obesity by targeting lower occupational groups. However, overall, the evidence base is small, largely from the USA, and of a low quality. More high-quality, experimental study designs are required. PMID:25316262

  12. Experimental Observation of Bulk Liquid Water Structure in ``No Man's Land''

    NASA Astrophysics Data System (ADS)

    Sellberg, Jonas; McQueen, Trevor; Huang, Congcong; Loh, Duane; Laksmono, Hartawan; Sierra, Raymond; Hampton, Christina; Starodub, Dmitri; Deponte, Daniel; Martin, Andrew; Barty, Anton; Wikfeldt, Thor; Schlesinger, Daniel; Pettersson, Lars; Beye, Martin; Nordlund, Dennis; Weiss, Thomas; Feldkamp, Jan; Caronna, Chiara; Seibert, Marvin; Messerschmidt, Marc; Williams, Garth; Boutet, Sebastien; Bogan, Michael; Nilsson, Anders

    2013-03-01

    Experiments on pure bulk water below about 235 K have so far been difficult: water crystallization occurs very rapidly below the homogeneous nucleation temperature of 232 K and above 160 K, leading to a ``no man's land'' devoid of experimental results regarding the structure. Here, we demonstrate a new, general experimental approach to study the structure of liquid states at supercooled conditions below their limit of homogeneous nucleation. We use femtosecond x-ray pulses generated by the LCLS x-ray laser to probe evaporatively cooled droplets of supercooled bulk water and find experimental evidence for the existence of metastable bulk liquid water down to temperatures of 223 K in the previously largely unexplored ``no man's land''. We acknoweledge NSF (CHE-0809324), Office of Basic Energy Sciences, and the Swedish Research Council for financial support.

  13. Proposed key characteristics of male reproductive toxicants as a method for organizing and screening mechanistic evidence for non-cancer outcomes.

    EPA Science Inventory

    The adoption of systematic review practices for risk assessment includes integration of evidence obtained from experimental, epidemiological, and mechanistic studies. Although mechanistic evidence plays an important role in mode of action analysis, the process of sorting and anal...

  14. Experimental evidence for asymmetric mate preference and aggression: behavioral interactions in a woodrat (Neotoma) hybrid zone

    PubMed Central

    2013-01-01

    Background Female mate preferences may be under strong selection in zones of contact between closely related species because of greater variation in available mates and the potential costs of hybridization. We studied female mate preferences experimentally in a zone of secondary contact between Desert and Bryant’s Woodrat (Neotoma lepida and N. bryanti) in the southern foothills of the Sierra Nevada of California. We tested female preference for conspecific versus heterospecific males in paired choice trials in which females could interact freely with males, but males could not interact directly with each other. We compared preferences of females from both allopatric and sympatric sites. Results We did not find evidence of the process of reinforcement as assortative preferences were not stronger in sympatry than in allopatry. Mate preferences, however, were asymmetric, with N. lepida females mating preferentially with conspecifics and N. bryanti females showing no preference by species. Sympatric females were less likely to mate than allopatric females, due in part to an increase in aggressive interactions. However, even in the absence of aggression, courtship led to mating less often in sympatric females, suggesting they were choosier or had lower sexual motivation than allopatric females. Conclusions Patterns of mate choice in this woodrat system appear to be strongly impacted by body size and aggressive behavior. In particular, females of the smaller-bodied species rarely interact with the relatively large heterospecific males. In contrast females of the larger-bodied species accept the relatively small heterospecific males. For sympatric animals, rates of aggression were markedly higher than for allopatric animals and reduced affiliative and reproductive behavior in our trials. Sympatric animals are larger and more aggressive, traits that are likely under strong ecological selection across the sharp resource gradient that characterizes the contact zone

  15. Experimental evidence for an optical interference model for vibrational sum frequency generation on multilayer organic thin film systems. I. Electric dipole approximation.

    PubMed

    O'Brien, Daniel B; Massari, Aaron M

    2015-01-14

    In the field of vibrational sum frequency generation spectroscopy (VSFG) applied to organic thin film systems, a significant challenge to data analysis is in the accurate description of optical interference effects. Herein, we provide experimental evidence that a model recently developed in our lab provides an accurate description of this phenomenon. We studied the organic small molecule N,N'-dioctyl-3,4,9,10-perylenedicarboximide vapor deposited as a thickness gradient on silicon wafer substrates with two oxide thicknesses and two surface preps. VSFG data were obtained using the ssp and the sps polarization combinations in the imide carbonyl stretching region as a function of organic thickness. In this first of two reports, the data are modeled and interpreted within the ubiquitous electric dipole approximation for VSFG. The intrinsic sample responses are parameterized during the fitting routines while optical interference effects are simply calculated from the model using known refractive indices, thin film thicknesses, and beam angles. The results indicate that the thin film model provides a good description of optical interferences, indicating that interfacial terms are significant. Inconsistencies between the fitting results within the bounds of the electric dipole response motivate deliberation for additional effects to be considered in the second report.

  16. Experimental myocardial infarction

    PubMed Central

    Kumar, Raj; Joison, Julio; Gilmour, David P.; Molokhia, Farouk A.; Pegg, C. A. S.; Hood, William B.

    1971-01-01

    The hemodynamic effects of tachycardia induced by atrial pacing were investigated in left ventricular failure of acute and healing experimental myocardial infarction in 20 intact, conscious dogs. Myocardial infarction was produced by gradual inflation of a balloon cuff device implanted around the left anterior descending coronary artery 10-15 days prior to the study. 1 hr after acute myocardial infarction, atrial pacing at a rate of 180 beats/min decreased left ventricular end-diastolic pressure from 19 to 8 mm Hg and left atrial pressure from 17 to 12 mm Hg, without change in cardiac output. In the healing phase of myocardial infarction 1 wk later, atrial pacing decreased left ventricular end-diastolic pressure from 17 to 9 mm Hg and increased the cardiac output by 37%. This was accompanied by evidence of peripheral vasodilation. In two dogs with healing anterior wall myocardial infarction, left ventricular failure was enhanced by partial occlusion of the circumflex coronary artery. Both the dogs developed pulmonary edema. Pacing improved left ventricular performance and relieved pulmonary edema in both animals. In six animals propranolol was given after acute infarction, and left ventricular function deteriorated further. However the pacing-induced augmentation of cardiac function was unaltered and, hence, is not mediated by sympathetics. The results show that the spontaneous heart rate in left ventricular failure of experimental canine myocardial infarction may be less than optimal and that maximal cardiac function may be achieved at higher heart rates. Images PMID:4395910

  17. Evidence of experimental postcyclic transmission of Bothriocephalus acheilognathi in bonytail chub (Gila elegans)

    USGS Publications Warehouse

    Hansen, S.P.; Choudhury, A.; Cole, Rebecca A.

    2007-01-01

    We examined the role that predation of infected conspecific fish and postcyclic transmission might play in the life cycle of the Asian fish tapeworm, Bothriocephalus acheilognathi (Cestoda: Pseudophyllidea) Yamaguti, 1934. Young-of-the-year (YOY) bonytail chub (Gila elegans) were exposed to copepods infected with B. acheilognathi and subsequently fed to subadult bonytail chub. Within 1 wk after consumption of the YOY chub, subadults were necropsied and found infected with gravid and nongravid tapeworms. This study provides evidence that postcyclic transfer of B. acheilognathi can occur. Postcyclic transmission may be an important life history trait of B. acheilognathi that merits consideration when studying the impact and distribution of this invasive and potentially pathogenic tapeworm.

  18. Experimental rabies in a great horned owl.

    PubMed

    Jorgenson, R D; Gough, P M; Graham, D L

    1976-07-01

    A great horned owl (Bubo virginianus) was fed the carcass of an experimentally infected rabid skunk. The bird developed antibody titer to rabies, detected by passive haemagglutination, 27 days after oral inoculation by ingestion. The owl suppressed the infection until corticosteroid administration, after which a maximum antibody titer was attained. Evidence of active rabies viral infection was seen by fluorescent antibody staining of oral swabs, corneal impression smears and histologic tissue smears, by suckling mouse inoculation of oral swab washings, and by transmission electron microcopy. No clinical signs of rabies virus infection were observed.

  19. Effects of 4% Icodextrin on Experimental Spinal Epidural Fibrosis.

    PubMed

    Karanci, Turker; Kelten, Bilal; Karaoglan, Alper; Cinar, Nilgun; Midi, Ahmet; Antar, Veysel; Akdemir, Hidayet; Kara, Zeynep

    2017-01-01

    The aim of this experimental study was to investigate whether spinal epidural 4% glucose polymer solution is effective in the prevention of postoperative fibrosis. Twenty eight adult Wistar albino rats were randomly divided into two equal groups, including treatment and control. Both groups underwent L1 vertebral total laminectomy to expose the dura. Topical treatment group received 4% icodextrin. Four weeks later, epidural fibrosis was examined in both groups histologically, biochemically and macroscopically. Topical use of 4% icodextrin prevented significantly epidural fibrosis following the laminectomy operation. Topical 4% icodextrin application inhibits postoperative epidural fibrosis with various mechanisms and prevents adhesions by playing barrier role between tissue surfaces through flotation. Our study is first to present evidence of experimental epidural fibrosis prevention with 4% icodextrin.

  20. Methodological individualism in experimental games: not so easily dismissed.

    PubMed

    Krueger, Joachim I

    2008-06-01

    Orthodox game theory and social preference models cannot explain why people cooperate in many experimental games or how they manage to coordinate their choices. The theory of evidential decision making provides a solution, based on the idea that people tend to project their own choices onto others, whatever these choices might be. Evidential decision making preserves methodological individualism, and it works without recourse to social preferences. Rejecting methodological individualism, team reasoning is a thinly disguised resurgence of the group mind fallacy, and the experiments reported by Colman et al. [Colman, A. M., Pulford, B. D., & Rose, J. (this issue). Collective rationality in interactive decisions: Evidence for team reasoning. Acta Psychologica, doi:10.1016/j.actpsy.2007.08.003.] do not offer evidence that uniquely supports team reasoning.

  1. Replicating Experimental Impact Estimates Using a Regression Discontinuity Approach. NCEE 2012-4025

    ERIC Educational Resources Information Center

    Gleason, Philip M.; Resch, Alexandra M.; Berk, Jillian A.

    2012-01-01

    This NCEE Technical Methods Paper compares the estimated impacts of an educational intervention using experimental and regression discontinuity (RD) study designs. The analysis used data from two large-scale randomized controlled trials--the Education Technology Evaluation and the Teach for America Study--to provide evidence on the performance of…

  2. Experimental giardiasis in goat kids.

    PubMed

    Koudela, B; Vítovec, J

    1998-01-15

    The clinical, pathological and parasitological features of giardiasis resulting from experimental inoculation with 3 x 10(6) Giardia cysts were studied in goat kids. All experimentally inoculated goat kids given Giardia cysts became infected. Three of the eight inoculated kids had decreased appetite, formless feces and become slightly depressed beginning 7 or 8 days post inoculation. The mean duration of the appearance of abnormal feces was 6 days. Irregular and intermitted cysts shedding started after prepatent periods of 6-10 days and lasted throughout this study (10 weeks). The evidence of high infectivity and fast transmission of Giardia were observed under standard zoohygienic conditions. The characteristics of intestinal lesions were similar to those found in other hosts infected with Giardia. The most severe lesions were seen in the duodenum and proximal jejunum, and consisted of moderate villus atrophy, villus blunting, crypt hyperplasia and inflammatory infiltration in the lamina propria. Scanning electron microscopy revealed ultrastructural alterations in the microvillus border of enterocytes. Mucosal smears and histological sections of the gall bladder displayed Giardia trophozoites and gall bladder epithelium hyperplasia together with bile ductular proliferation in the liver tissue in two kids.

  3. Encouraging the Flight of Error: Ethical Standards, Evidence Standards, and Randomized Trials

    ERIC Educational Resources Information Center

    Boruch, Robert

    2007-01-01

    Thomas Jefferson recognized the value of reason and scientific experimentation in the eighteenth century. This chapter extends the idea in contemporary ways to standards that may be used to judge the ethical propriety of randomized trials and the dependability of evidence on effects of social interventions.

  4. Cognitive Contributions to Gait and Falls: Evidence and Implications

    PubMed Central

    Amboni, Marianna; Barone, Paolo; Hausdorff, Jeffrey M.

    2014-01-01

    Dementia and gait impairments often coexist in older adults and patients with neurodegenerative disease. Both conditions represent independent risk factors for falls. The relationship between cognitive function and gait has recently received increasing attention. Gait is no longer considered merely automated motor activity but rather an activity that requires executive function and attention as well as judgment of external and internal cues. In this review, we intend to: (1) summarize and synthesize the experimental, neuropsychological, and neuroimaging evidence that supports the role played by cognition in the control of gait; and (2) briefly discuss the implications deriving from the interplay between cognition and gait. In recent years, the dual task paradigm has been widely used as an experimental method to explore the interplay between gait and cognition. Several neuropsychological investigations have also demonstrated that walking relies on the use of several cognitive domains, including executive-attentional function, visuospatial abilities, and even memory resources. A number of morphological and functional neuroimaging studies have offered additional evidence supporting the relationship between gait and cognitive resources. Based on the findings from 3 lines of studies, it appears that a growing body of evidence indicates a pivotal role of cognition in gait control and fall prevention. The interplay between higher-order neural function and gait has a number of clinical implications, ranging from integrated assessment tools to possible innovative lines of interventions, including cognitive therapy for falls prevention on one hand and walking program for reducing dementia risk on the other. PMID:24132840

  5. Experimental evidence of beam-foil plasma creation during ion-solid interaction

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sharma, Prashant, E-mail: prashant@iuac.res.in; Nandi, Tapan

    2016-08-15

    Charge state evolution of the energetic projectile ions during the passage through thin carbon foils has been revisited using the X-ray spectroscopy technique. Contributions from the bulk and the solid surface in the charge changing processes have been segregated by measuring the charge state distribution of the projectile ions in the bulk of the target during the ion–solid interaction. Interestingly, the charge state distribution measured in the bulk exhibits Lorentzian profile in contrast to the well-known Gaussian structure observed using the electromagnetic methods and the theoretical predictions. The occurrence of such behavior is a direct consequence of the imbalance betweenmore » charge changing processes, which has been seen in various cases of the laboratory plasma. It suggests that the ion-solid collisions constitute high-density, localized plasma in the bulk of the solid target, called the beam-foil plasma. This condensed beam-foil plasma is similar to the high-density solar and stellar plasma which may have practical implementations in various fields, in particular, plasma physics and nuclear astrophysics. The present work suggests further modification in the theoretical charge state distribution calculations by incorporating the plasma coupling effects during the ion–solid interactions. Moreover, the multi-electron capture from the target exit surface has been confirmed through comparison between experimentally measured and theoretically predicted values of the mean charge state of the projectile ions.« less

  6. Pre-existing periodontitis exacerbates experimental arthritis in a mouse model.

    PubMed

    Cantley, Melissa D; Haynes, David R; Marino, Victor; Bartold, P Mark

    2011-06-01

    Previous studies have shown a higher incidence of alveolar bone loss in patients with rheumatoid arthritis (RA) and that patients with periodontitis are at a greater risk of developing RA. The aim of this study was to develop an animal model to assess the relationship between pre-existing periodontitis and experimental arthritis (EA). Periodontitis was first induced in mice by oral gavage with Porphyromonas gingivalis followed by EA using the collagen antibody-induced arthritis model. These animals were compared with animals with periodontitis alone, EA alone and no disease (controls). Visual changes in paw swelling were assessed to determine clinical development of EA. Alveolar bone and joint changes were assessed using micro-CT, histological analyses and immunohistochemistry. Serum levels of C-reactive protein were used to monitor systemic inflammation. Mice with pre-existing periodontitis developed more severe arthritis, which developed at a faster rate. Mice with periodontitis only also showed evidence of loss of bone within the radiocarpal joint. There was also evidence of alveolar bone loss in mice with EA alone. The results of this study indicate that pre-existing periodontitis exacerbated experimental arthritis in a mouse model. © 2011 John Wiley & Sons A/S.

  7. Experimental Aerodynamic Derivatives of a Sinusoidally Oscillating Airfoil in Two-Dimensional Flow

    NASA Technical Reports Server (NTRS)

    Halfman, Robert L

    1952-01-01

    Experimental measurements of the aerodynamic reactions on a symmetrical airfoil oscillating harmonically in a two-dimensional flow are presented and analyzed. Harmonic motions include pure pitch and pure translation, for several amplitudes and superimposed on an initial angle of attack, as well as combined pitch and translation. The apparatus and testing program are described briefly and the necessary theoretical background is presented. In general, the experimental results agree remarkably well with the theory, especially in the case of the pure motions. The net work per cycle for a motion corresponding to flutter is experimentally determined to be zero. Considerable consistent data for pure pitch were obtained from a search of available reference material, and several definite Reynolds number effects are evident.

  8. Treatment of Fever After Stroke: Conflicting Evidence

    PubMed Central

    Wrotek, Sylwia E.; Kozak, Wieslaw E.; Hess, David C.; Fagan, Susan C.

    2014-01-01

    Approximately 50% of patients hospitalized for stroke develop fever. In fact, experimental evidence suggests that high body temperature is significantly correlated to initial stroke severity, lesion size, mortality, and neurologic outcome. Fever occurring after stroke is associated with poor outcomes. We investigated the etiology of fever after stroke and present evidence evaluating the efficacy and safety of interventions used to treat stroke-associated fever. Oral antipyretics are only marginally effective in lowering elevated body temperature in this population and may have unintended adverse consequences. Nonpharmacologic approaches to cooling have been more effective in achieving normothermia, but whether stroke outcomes can be improved remains unclear. We recommend using body temperature as a biomarker and a catalyst for aggressive investigation for an infectious etiology. Care must be taken not to exceed the new standard of a maximum acetaminophen does of 3 g/day to avoid patient harm. PMID:22026396

  9. Quantitative evaluation of human cerebellum-dependent motor learning through prism adaptation of hand-reaching movement.

    PubMed

    Hashimoto, Yuji; Honda, Takeru; Matsumura, Ken; Nakao, Makoto; Soga, Kazumasa; Katano, Kazuhiko; Yokota, Takanori; Mizusawa, Hidehiro; Nagao, Soichi; Ishikawa, Kinya

    2015-01-01

    The cerebellum plays important roles in motor coordination and learning. However, motor learning has not been quantitatively evaluated clinically. It thus remains unclear how motor learning is influenced by cerebellar diseases or aging, and is related with incoordination. Here, we present a new application for testing human cerebellum-dependent motor learning using prism adaptation. In our paradigm, the participant wearing prism-equipped goggles touches their index finger to the target presented on a touchscreen in every trial. The whole test consisted of three consecutive sessions: (1) 50 trials with normal vision (BASELINE), (2) 100 trials wearing the prism that shifts the visual field 25° rightward (PRISM), and (3) 50 trials without the prism (REMOVAL). In healthy subjects, the prism-induced finger-touch error, i.e., the distance between touch and target positions, was decreased gradually by motor learning through repetition of trials. We found that such motor learning could be quantified using the "adaptability index (AI)", which was calculated by multiplying each probability of [acquisition in the last 10 trials of PRISM], [retention in the initial five trials of REMOVAL], and [extinction in the last 10 trials of REMOVAL]. The AI of cerebellar patients less than 70 years old (mean, 0.227; n = 62) was lower than that of age-matched healthy subjects (0.867, n = 21; p < 0.0001). While AI did not correlate with the magnitude of dysmetria in ataxic patients, it declined in parallel with disease progression, suggesting a close correlation between the impaired cerebellar motor leaning and the dysmetria. Furthermore, AI decreased with aging in the healthy subjects over 70 years old compared with that in the healthy subjects less than 70 years old. We suggest that our paradigm of prism adaptation may allow us to quantitatively assess cerebellar motor learning in both normal and diseased conditions.

  10. Quantitative Evaluation of Human Cerebellum-Dependent Motor Learning through Prism Adaptation of Hand-Reaching Movement

    PubMed Central

    Hashimoto, Yuji; Honda, Takeru; Matsumura, Ken; Nakao, Makoto; Soga, Kazumasa; Katano, Kazuhiko; Yokota, Takanori; Mizusawa, Hidehiro; Nagao, Soichi; Ishikawa, Kinya

    2015-01-01

    The cerebellum plays important roles in motor coordination and learning. However, motor learning has not been quantitatively evaluated clinically. It thus remains unclear how motor learning is influenced by cerebellar diseases or aging, and is related with incoordination. Here, we present a new application for testing human cerebellum-dependent motor learning using prism adaptation. In our paradigm, the participant wearing prism-equipped goggles touches their index finger to the target presented on a touchscreen in every trial. The whole test consisted of three consecutive sessions: (1) 50 trials with normal vision (BASELINE), (2) 100 trials wearing the prism that shifts the visual field 25° rightward (PRISM), and (3) 50 trials without the prism (REMOVAL). In healthy subjects, the prism-induced finger-touch error, i.e., the distance between touch and target positions, was decreased gradually by motor learning through repetition of trials. We found that such motor learning could be quantified using the “adaptability index (AI)”, which was calculated by multiplying each probability of [acquisition in the last 10 trials of PRISM], [retention in the initial five trials of REMOVAL], and [extinction in the last 10 trials of REMOVAL]. The AI of cerebellar patients less than 70 years old (mean, 0.227; n = 62) was lower than that of age-matched healthy subjects (0.867, n = 21; p < 0.0001). While AI did not correlate with the magnitude of dysmetria in ataxic patients, it declined in parallel with disease progression, suggesting a close correlation between the impaired cerebellar motor leaning and the dysmetria. Furthermore, AI decreased with aging in the healthy subjects over 70 years old compared with that in the healthy subjects less than 70 years old. We suggest that our paradigm of prism adaptation may allow us to quantitatively assess cerebellar motor learning in both normal and diseased conditions. PMID:25785588

  11. Short- and long-term memory contributions to immediate serial recognition: evidence from serial position effects.

    PubMed

    Purser, Harry; Jarrold, Christopher

    2010-04-01

    A long-standing body of research supports the existence of separable short- and long-term memory systems, relying on phonological and semantic codes, respectively. The aim of the current study was to measure the contribution of long-term knowledge to short-term memory performance by looking for evidence of phonologically and semantically coded storage within a short-term recognition task, among developmental samples. Each experimental trial presented 4-item lists. In Experiment 1 typically developing children aged 5 to 6 years old showed evidence of phonologically coded storage across all 4 serial positions, but evidence of semantically coded storage at Serial Positions 1 and 2. In a further experiment, a group of individuals with Down syndrome was investigated as a test case that might be expected to use semantic coding to support short-term storage, but these participants showed no evidence of semantically coded storage and evidenced phonologically coded storage only at Serial Position 4, suggesting that individuals with Down syndrome have a verbal short-term memory capacity of 1 item. Our results suggest that previous evidence of semantic effects on "short-term memory performance" does not reflect semantic coding in short-term memory itself, and provide an experimental method for researchers wishing to take a relatively pure measure of verbal short-term memory capacity, in cases where rehearsal is unlikely.

  12. Critical Assessment of the Evidence for Striped Nanoparticles

    PubMed Central

    Stirling, Julian; Lekkas, Ioannis; Sweetman, Adam; Djuranovic, Predrag; Guo, Quanmin; Pauw, Brian; Granwehr, Josef; Lévy, Raphaël; Moriarty, Philip

    2014-01-01

    There is now a significant body of literature which reports that stripes form in the ligand shell of suitably functionalised Au nanoparticles. This stripe morphology has been proposed to strongly affect the physicochemical and biochemical properties of the particles. We critique the published evidence for striped nanoparticles in detail, with a particular focus on the interpretation of scanning tunnelling microscopy (STM) data (as this is the only technique which ostensibly provides direct evidence for the presence of stripes). Through a combination of an exhaustive re-analysis of the original data, in addition to new experimental measurements of a simple control sample comprising entirely unfunctionalised particles, we show that all of the STM evidence for striped nanoparticles published to date can instead be explained by a combination of well-known instrumental artefacts, or by issues with data acquisition/analysis protocols. We also critically re-examine the evidence for the presence of ligand stripes which has been claimed to have been found from transmission electron microscopy, nuclear magnetic resonance spectroscopy, small angle neutron scattering experiments, and computer simulations. Although these data can indeed be interpreted in terms of stripe formation, we show that the reported results can alternatively be explained as arising from a combination of instrumental artefacts and inadequate data analysis techniques. PMID:25402426

  13. In-Situ and Experimental Evidence for Acidic Weathering of Rocks and Soils on Mars

    NASA Technical Reports Server (NTRS)

    Hurowitz, J. A.; McLennan, S. M.; Tosca, N. J.; Arvidson, R. E.; Michalski, J. R.; Ming, D.; Schroeder, C.; Squyres, S. W.

    2006-01-01

    Experimental data for alteration of synthetic Martian basalts at pH=0-1 indicate that chemical fractionations at low pH are vastly different from those observed during terrestrial weathering. Rock analyses from Gusev crater are well described by the relationships apparent from low pH experimental alteration data. A model for rock surface alteration is developed which indicates that a leached alteration zone is present on rock surfaces at Gusev. This zone is not chemically fractionated to a large degree from the underlying rock interior, indicating that the rock surface alteration process has occurred at low fluid-to-rock ratio. The geochemistry of natural rock surfaces analyzed by APXS is consistent with a mixture between adhering soil/dust and the leached alteration zone. The chemistry of rock surfaces analyzed after brushing with the RAT is largely representative of the leached alteration zone. The chemistry of rock surfaces analyzed after grinding with the RAT is largely representative of the interior of the rock, relatively unaffected by the alteration process occurring at the rock surface. Elemental measurements from the Spirit, Opportunity, Pathfinder and Viking 1 landing sites indicate that soil chemistry from widely separated locations is consistent with the low-pH, low fluid to rock ratio alteration relationships developed for Gusev rocks. Soils are affected principally by mobility of FeO and MgO, consistent with alteration of olivine-bearing basalt and subsequent precipitation of FeO and MgO bearing secondary minerals as the primary control on soil geochemistry.

  14. Experimental Investigation of Compressed Thin-Walled Steel Members

    NASA Astrophysics Data System (ADS)

    Juhás, Pavol; Juhásová Šenitková, Ingrid

    2017-10-01

    The paper presents fundamental information about realized experimental-theoretical research to determinate the load-carrying capacities for thin-walled compressed steel members with quasi-homogenous and hybrid cross-sections. The webs of such members are stressed in the elastic-plastic region. This continuous research joins on previous research of the first author of the paper. The aim of this research is to investigate and analyse the elastic-plastic post-critical behaviour of thin web and its interaction with flanges. The experimental program, test members and their geometrical parameters and material properties are evident from table 1 and table 2 as well as from figure 1 and figure 2. The test arrangement and failures of the test members are illustrated on Figures 3, 4 and 5. Some partial results are presented in Table 3 of the paper, too.

  15. Culturally Responsive Experimental Intervention Studies: The Development of a Rubric for Paradigm Expansion

    ERIC Educational Resources Information Center

    Bal, Aydin; Trainor, Audrey A.

    2016-01-01

    Neither legislative demand for evidence-based practices nor a focus on experimental designs for educational interventions has ameliorated the disparate educational opportunities and outcomes for youth from nondominant cultural and linguistic backgrounds. Recent initiatives to increase the rigor of intervention research in special education have…

  16. Message and price components of Family Caps: experimental evidence from New Jersey.

    PubMed

    Jagannathan, Radha; Camasso, Michael J

    2011-08-01

    In this paper, we examine the relative efficacy of two mechanisms--price consideration and the message of social responsibility--in accounting for Family Cap effects on fertility behavior. The Family Cap is a component of welfare reform policy that denies additional cash benefits to children born 10 or more months after a woman entered the welfare rolls. We use data from the New Jersey Family Development Program (FDP) evaluation that employed a classical experimental design. We find that fertility behaviors are influenced by both Family Cap price and message mechanisms but that these effects are conditioned by welfare recipients' time on welfare and race. Black women who have longer stays on welfare are more likely to be influenced by price while women with shorter stays are influenced by both price and the social message. We believe our results have implications not only for future public welfare policy initiatives but for any social policies that attempt to influence behavior directly, through individual rewards and punishments, and indirectly through the activation of social or community pressures. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Experimental evidence for a phase transition in magnesium oxide at exoplanet pressures

    DOE PAGES

    Coppari, F.; Smith, R. F.; Eggert, J. H.; ...

    2013-09-22

    Here, magnesium oxide, an important component of the Earth’s mantle, has been extensively studied in the pressure and temperature range found within the Earth. However,much less is known about its behavior under conditions appropriate for newly-discovered super-Earth planets, where pressures can exceed 1000 GPa (10 Mbar). It is widely believed that MgO will follow the rocksalt (B1) to cesium chloride (B2) transformation pathway commonly found for many alkali halides, alkaline earth oxides and various other ionic compounds. Static compression experiments have determined the structure of MgO to 250 GPa but have been unable to reach pressures necessary to induce themore » predicted transformation, resulting in large uncertainties regarding its properties under conditions relevant to super-Earths and other large planets. Here we report new dynamic x-ray diffraction measurements of ramp-compressed MgO to 900 GPa.We report evidence for the B2 phase beginning near 600 GPa, remaining stable on further compression to 900 GPa, the highest pressure diffraction data ever collected.« less

  18. In silico modeling and experimental evidence of coagulant protein interaction with precursors for nanoparticle functionalization.

    PubMed

    Okoli, Chuka; Sengottaiyan, Selvaraj; Arul Murugan, N; Pavankumar, Asalapuram R; Agren, Hans; Kuttuva Rajarao, Gunaratna

    2013-10-01

    The design of novel protein-nanoparticle hybrid systems has applications in many fields of science ranging from biomedicine, catalysis, water treatment, etc. The main barrier in devising such tool is lack of adequate information or poor understanding of protein-ligand chemistry. Here, we establish a new strategy based on computational modeling for protein and precursor linkers that can decorate the nanoparticles. Moringa oleifera (MO2.1) seed protein that has coagulation and antimicrobial properties was used. Superparamagnetic nanoparticles (SPION) with precursor ligands were used for the protein-ligand interaction studies. The molecular docking studies reveal that there are two binding sites, one is located at the core binding site; tetraethoxysilane (TEOS) or 3-aminopropyl trimethoxysilane (APTES) binds to this site while the other one is located at the side chain residues where trisodium citrate (TSC) or Si60 binds to this site. The protein-ligand distance profile analysis explains the differences in functional activity of the decorated SPION. Experimentally, TSC-coated nanoparticles showed higher coagulation activity as compared to TEOS- and APTES-coated SPION. To our knowledge, this is the first report on in vitro experimental data, which endorses the computational modeling studies as a powerful tool to design novel precursors for functionalization of nanomaterials; and develop interface hybrid systems for various applications.

  19. Evidence for distinct chronic wasting disease (CWD) strains in experimental CWD in ferrets

    PubMed Central

    Perrott, Matthew R.; Sigurdson, Christina J.; Mason, Gary L.

    2012-01-01

    Chronic wasting disease (CWD) is an evolving prion disease of cervids (deer, elk and moose) that has been recognized in North America and Korea. Infection of non-cervid reservoir or transport species in nature is not reported. However, the ferret (Mustela putorius furo) is susceptible to CWD after experimental inoculation. Here, we report that infection of ferrets with either of two ferret CWD isolates by various routes of exposure has revealed biologically distinct strain-like properties distinguished by different clinical progression and survival period. The isolates of ferret CWD were also differentiated by the distribution of the infectious prion protein (PrPCWD) in the brain and periphery, and by the proteinase K sensitivity of PrPCWD. These findings suggest that diversity in prion conformers exists in CWD-infected cervids. PMID:21918005

  20. Cocoa Polyphenols: Evidence from Epidemiological Studies.

    PubMed

    Matsumoto, Chisa

    2018-01-01

    Accumulating evidence suggests potential preventive effects of chocolate/cocoa on the risk of cardio vascular disease (CVD). However, cocoa products also contain high levels of sugar and fat, which increase CVD risk factors. Even, the identity of the substance in chocolate/cocoa that has a favorable effect on CVD and CVD risk factors remains unclear, growing evidence from experimental studies suggests that cocoa polyphenols might be a major contributor to cardiovascular-protective effects. However, epidemiological studies, which are necessary to evaluate an association between the risk of CVD and cocoa polyphenol, remain sparse. We will discuss recent evidence regarding the association between cocoa polyphenol consumption and the risks of CVD and its risk factors by reviewing recent epidemiological studies. We shall also provide some guidance for patient counseling and will discuss the public health implications for recommending cocoa polyphenol consumption to prevent CVD. Epidemiological studies evaluating the association between cocoa polyphenol itself and the risk of CVD are sparse. However, evidence from limited epidemiological studies suggests that cocoa polyphenol consumption may lower the risk of CVD. Given the potential adverse effects of the consumption of cocoa products with high fat and sugar and the fact that the most appropriate dose of cocoa polyphenol for cardio-protective effects has not yet been established, health care providers should remain cautious about recommending cocoa/cocoa polyphenol consumption to their patients to reduce the risk of CVD, taking the characteristics of individual patients into careful consideration. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  1. The Effects of Television Advertising on Children. Report No. 2: Second Year Experimental Evidence. Final Report.

    ERIC Educational Resources Information Center

    Atkin, Charles K.

    This report, the second in a series of six reports on television advertising and children, presents the results from a series of experimental studies designed to test children's intentional and incidental learning from television commercials. A total of 400 elementary school students of varying socioeconomic status participated in the study, with…

  2. Cognitive rehabilitation in epilepsy: An evidence-based review.

    PubMed

    Farina, Elisabetta; Raglio, Alfredo; Giovagnoli, Anna Rita

    2015-01-01

    To review the modalities of cognitive rehabilitation (CR), outcome endpoints, and the levels of evidence of efficacy of different interventions. A systematic research in Pubmed, Psychinfo, and SCOPUS was performed assessing the articles written in the entire period covered by these databases till December 2013. Articles in English, Spanish or French were evaluated. A manual research evaluated the references of all of the articles. The experimental studies were classified according to the level of evidence of efficacy, using a standardized Italian method (SPREAD, 2007), adopting the criteria reported by Cicerone et al. (2000, 2011). Eighteen papers were classified into two reviews, four papers dealing with the principles and efficacy of CR in epilepsy, a methodological paper, a single-case report, a multiple-case report, and nine experimental papers. Most studies involved patients with temporal lobe epilepsy. Different types of CR were used to treat patients with epilepsy. A holistic rehabilitation approach was more useful than selective interventions to treat memory and attention disturbances. CR may be a useful tool to treat cognitive impairment in patients with epilepsy. However, the modalities of treatment and outcome endpoints are important concerns of clinical care and research. Controlled studies are needed to determine the efficacy of rehabilitation in well-defined groups of patients with epilepsy. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Experimental observation of direct particle acceleration by stimulated emission of radiation.

    PubMed

    Banna, Samer; Berezovsky, Valery; Schächter, Levi

    2006-09-29

    We report the first experimental evidence for direct particle acceleration by stimulated emission of radiation. In the framework of this proof-of-principle experiment, a 45 MeV electron macrobunch was modulated by a high-power CO2 laser and then injected into an excited CO2 gas mixture. The emerging microbunches experienced a 0.15% relative change in the kinetic energy, in a less than 40 cm long interaction region. According to our experimental results, a fraction of these electrons have gained more than 200 keV each, implying that such an electron has undergone an order of magnitude of 2 x 10(6) collisions of the second kind.

  4. Experimental cryptosporidiosis in kids.

    PubMed

    Koudela, B; Jirí, V

    1997-08-01

    The clinical, pathological and parasitological features of cryptosporidiosis resulting from experimental inoculation with 6 x 10(6) Cryptosporidium parvum oocysts were studied in kids. Decreased appetite and depression became apparent 72 h post inoculation. Subsequently watery feces with clumps of mucus and color changes from brown to yellow were observed. The mean duration of diarrhea was 4.2 days. Oocyst shedding started 4 days post inoculation (DPI), started to decrease at 7 DPI, and lasted until 12 DPI. The evidence of high infectivity and fast transmission of C. parvum oocysts was observed under standard zoohygienic conditions. The characteristics of intestinal lesions were similar to those found in other neonatal ruminants infected with C. parvum. The most severe lesions were seen in the posterior jejunum and ileum from 3 to 7 DPI, characterized by villus atrophy, villus blunting, fusion of atrophic villi, crypt hyperplasia, inflammatory infiltration in the lamina propria, and metaplasia of mucosal epithelium. Scanning electron microscopy of ileal epithelium revealed ultrastructural changes on the surface of intestinal mucosa. No cryptosporidia or associated pathological lesions were found in the large intestine or other tissues. The distribution of cryptosporidia in the intestine and number of cryptosporidia per ileal villus on different DPI were also estimated for detailed characterization of the infection in kids as a model for experimental cryptosporidiosis.

  5. Quasi-experimental evaluation of a substance use awareness educational intervention for nursing students.

    PubMed

    Cadiz, David M; O'Neill, Chris; Butell, Sue S; Epeneter, Beverly J; Basin, Basilia

    2012-07-01

    This article reports on a study that evaluated the effectiveness of an educational intervention, Addressing Nurse Impairment, for addressing nursing students' knowledge acquisition, changes in self-efficacy to intervene, and changes in substance abuse stigma. A gap exists in nursing students' education regarding the risks of addiction within the profession and how to handle a colleague suspected of having a substance use disorder. The seminar was adapted from an existing evidence-based prevention program called Team Awareness, as well as information from focus groups and a pilot test. A quasi-experimental pretest-posttest design was used to evaluate the effect of the seminar. When the control and experimental groups were compared, the results indicated that the seminar significantly affected knowledge and self-efficacy to intervene but did not significantly affect stigma. This research contributes to the body of evidence related to educational interventions for nursing students regarding substance abuse in the nursing profession. Copyright 2012, SLACK Incorporated.

  6. What works best: objective statistics or a personal testimonial? An assessment of the persuasive effects of different types of message evidence on risk perception.

    PubMed

    de Wit, John B F; Das, Enny; Vet, Raymond

    2008-01-01

    In an experimental online study we compared the effects of different types of persuasive evidence in promoting the acceptance of a personal health risk. 118 men who have sex with men (MSM) at-risk for infection with the hepatitis B virus (HBV) were recruited via a range of websites and randomly assigned to one of 4 conditions (2 experimental and 2 control): narrative evidence (i.e., a personal account), statistical evidence (i.e., abstract prevalence data), mere assertion of increased risk, and no risk information. Narrative evidence was expected to be more effective than statistical evidence in increasing MSM's perceived risk of infection with HBV and intention to obtain vaccination. As predicted, perceptions of personal risk and intention to obtain vaccination against HBV were highest after presentation of narrative evidence, and risk perception mediated the effect of type of message evidence on intention. We propose that narrative evidence effectively promotes a sense of personal risk because it is less affected by defensive message processing resulting from the threat to important self-beliefs that seems inherent in health risk communication.

  7. Experimental evidence of coherent transport.

    PubMed

    Flores-Olmedo, E; Martínez-Argüello, A M; Martínez-Mares, M; Báez, G; Franco-Villafañe, J A; Méndez-Sánchez, R A

    2016-04-28

    Coherent transport phenomena are difficult to observe due to several sources of decoherence. For instance, in the electronic transport through quantum devices the thermal smearing and dephasing, the latter induced by inelastic scattering by phonons or impurities, destroy phase coherence. In other wave systems, the temperature and dephasing may not destroy the coherence and can then be used to observe the underlying wave behaviour of the coherent phenomena. Here, we observe coherent transmission of mechanical waves through a two-dimensional elastic Sinai billiard with two waveguides. The flexural-wave transmission, performed by non-contact means, shows the quantization when a new mode becomes open. These measurements agree with the theoretical predictions of the simplest model highlighting the universal character of the transmission fluctuations.

  8. Experimental evidence of coherent transport

    PubMed Central

    Flores-Olmedo, E.; Martínez-Argüello, A. M.; Martínez-Mares, M.; Báez, G.; Franco-Villafañe, J. A.; Méndez-Sánchez, R. A.

    2016-01-01

    Coherent transport phenomena are difficult to observe due to several sources of decoherence. For instance, in the electronic transport through quantum devices the thermal smearing and dephasing, the latter induced by inelastic scattering by phonons or impurities, destroy phase coherence. In other wave systems, the temperature and dephasing may not destroy the coherence and can then be used to observe the underlying wave behaviour of the coherent phenomena. Here, we observe coherent transmission of mechanical waves through a two-dimensional elastic Sinai billiard with two waveguides. The flexural-wave transmission, performed by non-contact means, shows the quantization when a new mode becomes open. These measurements agree with the theoretical predictions of the simplest model highlighting the universal character of the transmission fluctuations. PMID:27121226

  9. Experimental studies illuminate the cultural transmission of percussive technologies in Homo and Pan

    PubMed Central

    Whiten, Andrew

    2015-01-01

    The complexity of Stone Age tool-making is assumed to have relied upon cultural transmission, but direct evidence is lacking. This paper reviews evidence bearing on this question provided through five related empirical perspectives. Controlled experimental studies offer special power in identifying and dissecting social learning into its diverse component forms, such as imitation and emulation. The first approach focuses on experimental studies that have discriminated social learning processes in nut-cracking by chimpanzees. Second come experiments that have identified and dissected the processes of cultural transmission involved in a variety of other force-based forms of chimpanzee tool use. A third perspective is provided by field studies that have revealed a range of forms of forceful, targeted tool use by chimpanzees, that set percussion in its broader cognitive context. Fourth are experimental studies of the development of flint knapping to make functional sharp flakes by bonobos, implicating and defining the social learning and innovation involved. Finally, new and substantial experiments compare what different social learning processes, from observational learning to teaching, afford good quality human flake and biface manufacture. Together these complementary approaches begin to delineate the social learning processes necessary to percussive technologies within the Pan–Homo clade. PMID:26483537

  10. The Alkaline Hydrolysis of Sulfonate Esters: Challenges in Interpreting Experimental and Theoretical Data

    PubMed Central

    2013-01-01

    Sulfonate ester hydrolysis has been the subject of recent debate, with experimental evidence interpreted in terms of both stepwise and concerted mechanisms. In particular, a recent study of the alkaline hydrolysis of a series of benzene arylsulfonates (Babtie et al., Org. Biomol. Chem.10, 2012, 8095) presented a nonlinear Brønsted plot, which was explained in terms of a change from a stepwise mechanism involving a pentavalent intermediate for poorer leaving groups to a fully concerted mechanism for good leaving groups and supported by a theoretical study. In the present work, we have performed a detailed computational study of the hydrolysis of these compounds and find no computational evidence for a thermodynamically stable intermediate for any of these compounds. Additionally, we have extended the experimental data to include pyridine-3-yl benzene sulfonate and its N-oxide and N-methylpyridinium derivatives. Inclusion of these compounds converts the Brønsted plot to a moderately scattered but linear correlation and gives a very good Hammett correlation. These data suggest a concerted pathway for this reaction that proceeds via an early transition state with little bond cleavage to the leaving group, highlighting the care that needs to be taken with the interpretation of experimental and especially theoretical data. PMID:24279349

  11. Effects of low doses of alcohol on driving-related skills : a review of the evidence

    DOT National Transportation Integrated Search

    1988-07-01

    A large scale review of the experimental literature on alcohol effects on skills related to driving, considered 177 citations and explored the evidence of alcohol effects on reaction time, tracking, concentrated attention, divided attention performan...

  12. Supplying Disadvantaged Schools with Effective Teachers: Experimental Evidence on Secondary Math Teachers from Teach For America

    ERIC Educational Resources Information Center

    Chiang, Hanley S.; Clark, Melissa A.; McConnell, Sheena

    2017-01-01

    Teach For America (TFA) is an important but controversial source of teachers for hard-to-staff subjects in high-poverty U.S. schools. We present findings from the first large-scale experimental study of secondary math teachers from TFA. We find that TFA teachers are more effective than other math teachers in the same schools, increasing student…

  13. Anesthetics and analgesics in experimental traumatic brain injury: Selection based on experimental objectives

    PubMed Central

    Rowe, Rachel K.; Harrison, Jordan L.; Thomas, Theresa C.; Pauly, James R.; Adelson, P. David; Lifshitz, Jonathan

    2013-01-01

    The use of animal modeling in traumatic brain injury (TBI) research is justified by the lack of sufficiently comprehensive in vitro and computer modeling that incorporates all components of the neurovascular unit. Valid animal modeling of TBI requires accurate replication of both the mechanical forces and secondary injury conditions observed in human patients. Regulatory requirements for animal modeling emphasize the administration of appropriate anesthetics and analgesics unless withholding these drugs is scientifically justified. The objective of this review is to present scientific justification for standardizing the use of anesthetics and analgesics, within a study, when modeling TBI in order to preserve study validity. Evidence for the interference of anesthetics and analgesics in the natural course of brain injury calls for consistent consideration of pain management regimens when conducting TBI research. Anesthetics administered at the time of or shortly after induction of brain injury can alter cognitive, motor, and histological outcomes following TBI. A consistent anesthesia protocol based on experimental objectives within each individual study is imperative when conducting TBI studies to control for the confounding effects of anesthesia on outcome parameters. Experimental studies that replicate the clinical condition are essential to gain further understanding and evaluate possible treatments for TBI. However, with animal models of TBI it is essential that investigators assure a uniform drug delivery protocol that minimizes confounding variables, while minimizing pain and suffering. PMID:23877609

  14. Experimental evidence for convergent evolution of maternal care heuristics in industrialized and small-scale populations.

    PubMed

    Kushnick, Geoff; Hanowell, Ben; Kim, Jun-Hong; Langstieh, Banrida; Magnano, Vittorio; Oláh, Katalin

    2015-06-01

    Maternal care decision rules should evolve responsiveness to factors impinging on the fitness pay-offs of care. Because the caretaking environments common in industrialized and small-scale societies vary in predictable ways, we hypothesize that heuristics guiding maternal behaviour will also differ between these two types of populations. We used a factorial vignette experiment to elicit third-party judgements about likely caretaking decisions of a hypothetical mother and her child when various fitness-relevant factors (maternal age and access to resources, and offspring age, sex and quality) were varied systematically in seven populations-three industrialized and four small-scale. Despite considerable variation in responses, we found that three of five main effects, and the two severity effects, exhibited statistically significant industrialized/ small-scale population differences. All differences could be explained as adaptive solutions to industrialized versus small-scale caretaking environments. Further, we found gradients in the relationship between the population-specific estimates and national-level socio-economic indicators, further implicating important aspects of the variation in industrialized and small-scale caretaking environments in shaping heuristics. Although there is mounting evidence for a genetic component to human maternal behaviour, there is no current evidence for interpopulation variation in candidate genes. We nonetheless suggest that heuristics guiding maternal behaviour in diverse societies emerge via convergent evolution in response to similar selective pressures.

  15. Experimental evidence for beneficial effects of projected climate change on hibernating amphibians.

    PubMed

    Üveges, Bálint; Mahr, Katharina; Szederkényi, Márk; Bókony, Veronika; Hoi, Herbert; Hettyey, Attila

    2016-05-27

    Amphibians are the most threatened vertebrates today, experiencing worldwide declines. In recent years considerable effort was invested in exposing the causes of these declines. Climate change has been identified as such a cause; however, the expectable effects of predicted milder, shorter winters on hibernation success of temperate-zone Amphibians have remained controversial, mainly due to a lack of controlled experimental studies. Here we present a laboratory experiment, testing the effects of simulated climate change on hibernating juvenile common toads (Bufo bufo). We simulated hibernation conditions by exposing toadlets to current (1.5 °C) or elevated (4.5 °C) hibernation temperatures in combination with current (91 days) or shortened (61 days) hibernation length. We found that a shorter winter and milder hibernation temperature increased survival of toads during hibernation. Furthermore, the increase in temperature and shortening of the cold period had a synergistic positive effect on body mass change during hibernation. Consequently, while climate change may pose severe challenges for amphibians of the temperate zone during their activity period, the negative effects may be dampened by shorter and milder winters experienced during hibernation.

  16. The Infant Gut Microbiome: Evidence for Obesity Risk and Dietary Intervention

    PubMed Central

    Koleva, Petya T.; Bridgman, Sarah L.; Kozyrskyj, Anita L.

    2015-01-01

    Increasing globally, particularly in children, obesity is a serious public health issue and risk factor for overweight and metabolic disease in later life. Both in experimental animal and human studies, advances in gene sequencing technologies have yielded intriguing possibilities for the role of the gut microbiome in later development of overweight status. Before translating study findings into practice, we must first reconcile inconsistencies between animal experimentation, and human adult and infant studies. Recent evidence for associations with gut microbiota and infant weight gain or child weight status, implicate Bacteroides and Lactobacillus species. Dietary manipulation with human milk and pre/probiotic formulations holds promise for preventing obesity. PMID:25835047

  17. Experimental Evidence and In Silico Identification of Tryptophan Decarboxylase in Citrus Genus.

    PubMed

    De Masi, Luigi; Castaldo, Domenico; Pignone, Domenico; Servillo, Luigi; Facchiano, Angelo

    2017-02-11

    Plant tryptophan decarboxylase (TDC) converts tryptophan into tryptamine, precursor of indolealkylamine alkaloids. The recent finding of tryptamine metabolites in Citrus plants leads to hypothesize the existence of TDC activity in this genus. Here, we report for the first time that, in Citrus x limon seedlings, deuterium labeled tryptophan is decarboxylated into tryptamine, from which successively deuterated N , N , N -trimethyltryptamine is formed. These results give an evidence of the occurrence of the TDC activity and the successive methylation pathway of the tryptamine produced from the tryptophan decarboxylation. In addition, with the aim to identify the genetic basis for the presence of TDC, we carried out a sequence similarity search for TDC in the Citrus genomes using as a probe the TDC sequence reported for the plant Catharanthus roseus . We analyzed the genomes of both Citrus clementina and Citrus sinensis , available in public database, and identified putative protein sequences of aromatic l-amino acid decarboxylase. Similarly, 42 aromatic l-amino acid decarboxylase sequences from 23 plant species were extracted from public databases. Potential sequence signatures for functional TDC were then identified. With this research, we propose for the first time a putative protein sequence for TDC in the genus Citrus .

  18. Kinship and altruism: a cross-cultural experimental study.

    PubMed

    Madsen, Elainie A; Tunney, Richard J; Fieldman, George; Plotkin, Henry C; Dunbar, Robin I M; Richardson, Jean-Marie; McFarland, David

    2007-05-01

    Humans are characterized by an unusual level of prosociality. Despite this, considerable indirect evidence suggests that biological kinship plays an important role in altruistic behaviour. All previous reports of the influence of kin selection on human altruism have, however, used correlational (rather than experimental) designs, or imposed only a hypothetical or negligible time cost on participants. Since these research designs fail either to control for confounding variables or to meet the criteria required as a test of Hamilton's rule for kin selection (that the altruist pays a true cost), they fail to establish unequivocally whether kin selection plays a role. We show that individuals from two different cultures behave in accordance with Hamilton's rule by acting more altruistically (imposing a higher physical cost upon themselves) towards more closely related individuals. Three possible sources of confound were ruled out: generational effects, sexual attraction and reciprocity. Performance on the task however did not exhibit a perfect linear relationship with relatedness, which might reflect either the intrusion of other variables (e.g. cultural differences in the way kinship is costed) or that our behavioural measure is insufficiently sensitive to fine-tuned differences in the way individuals view their social world. These findings provide the first unequivocal experimental evidence that kinship plays a role in moderating altruistic behaviour. Kinship thus represents a baseline against which individuals pitch other criteria (including reciprocity, prosociality, obligation and a moral sense) when deciding how to behave towards others.

  19. Tunneling Evidence of Half-Metallic Ferromagnetism in La(0.7)Ca(0.3)MnO(3)

    NASA Technical Reports Server (NTRS)

    Wei, J. Y. T.; Yeh, N. C.; Vasquez, R. P.

    1997-01-01

    Direct experimental evidence of half-metallic density of states (DOS) is observed by scanning tunneling spectroscopy on ferromagnetic La(0.7)Ca(0.3)MnO(3) which exhibits colossal magnetoresistance (SMR).

  20. Three is a crowd in iterated prisoner's dilemmas: experimental evidence on reciprocal behavior

    NASA Astrophysics Data System (ADS)

    Grujić, Jelena; Eke, Burcu; Cabrales, Antonio; Cuesta, José A.; Sánchez, Angel

    2012-09-01

    Reciprocity or conditional cooperation is one of the most prominent mechanisms proposed to explain the emergence of cooperation in social dilemmas. Recent experimental findings on networked games suggest that conditional cooperation may also depend on the previous action of the player. We here report on experiments on iterated, multi-player Prisoner's dilemma, on groups of 2 to 5 people. We confirm the dependence on the previous step and that memory effects for earlier periods are not significant. We show that the behavior of subjects in pairwise dilemmas is qualitatively different from the cases with more players; After an initial decay, cooperation increases significantly reaching values above 80%. The strategy of the players is rather universal as far as their willingness to reciprocate cooperation is concerned, whereas there is much diversity in their initial propensity to cooperate. Our results indicate that, for cooperation to emerge and thrive, three is a crowd.

  1. Study design elements for rigorous quasi-experimental comparative effectiveness research.

    PubMed

    Maciejewski, Matthew L; Curtis, Lesley H; Dowd, Bryan

    2013-03-01

    Quasi-experiments are likely to be the workhorse study design used to generate evidence about the comparative effectiveness of alternative treatments, because of their feasibility, timeliness, affordability and external validity compared with randomized trials. In this review, we outline potential sources of discordance in results between quasi-experiments and experiments, review study design choices that can improve the internal validity of quasi-experiments, and outline innovative data linkage strategies that may be particularly useful in quasi-experimental comparative effectiveness research. There is an urgent need to resolve the debate about the evidentiary value of quasi-experiments since equal consideration of rigorous quasi-experiments will broaden the base of evidence that can be brought to bear in clinical decision-making and governmental policy-making.

  2. Experimental and Quasi-Experimental Design.

    ERIC Educational Resources Information Center

    Cottrell, Edward B.

    With an emphasis on the problems of control of extraneous variables and threats to internal and external validity, the arrangement or design of experiments is discussed. The purpose of experimentation in an educational institution, and the principles governing true experimentation (randomization, replication, and control) are presented, as are…

  3. Evidence Base Update for Autism Spectrum Disorder.

    PubMed

    Smith, Tristram; Iadarola, Suzannah

    2015-01-01

    This evidence base update examines the level of empirical support for interventions for children with autism spectrum disorder (ASD) younger than 5 years old. It focuses on research published since a previous review in this journal (Rogers & Vismara, 2008 ). We identified psychological or behavioral interventions that had been manualized and evaluated in either (a) experimental or quasi-experimental group studies or (b) systematic reviews of single-subject studies. We extracted data from all studies that met these criteria and were published after the previous review. Interventions were categorized across two dimensions. First, primary theoretical principles included applied behavior analysis (ABA), developmental social-pragmatic (DSP), or both. Second, practice elements included scope (comprehensive or focused), modality (individual intervention with the child, parent training, or classrooms), and intervention targets (e.g., spoken language or alternative and augmentative communication). We classified two interventions as well-established (individual, comprehensive ABA and teacher-implemented, focused ABA + DSP), 3 as probably efficacious (individual, focused ABA for augmentative and alternative communication; individual, focused ABA + DSP; and focused DSP parent training), and 5 as possibly efficacious (individual, comprehensive ABA + DSP; comprehensive ABA classrooms; focused ABA for spoken communication; focused ABA parent training; and teacher-implemented, focused DSP). The evidence base for ASD interventions has grown substantially since 2008. An increasing number of interventions have some empirical support; others are emerging as potentially efficacious. Priorities for future research include improving outcome measures, developing interventions for understudied ASD symptoms (e.g., repetitive behaviors), pinpointing mechanisms of action in interventions, and adapting interventions for implementation with fidelity by community providers.

  4. Experimental evidence that an asteroid impact LED to the extinction of many species 65 million years ago

    NASA Astrophysics Data System (ADS)

    Alvarez, L. W.

    1982-09-01

    The development of the theory that the mass extinction of the dinosaurs at the Cretaceous-Tertiary boundary was caused by as asteroid impact is reviewed. The scientists involved, the objections to the theory, and the evidence refuting those objections are presented chronologically.

  5. Experimental evidence that an asteroid impact led to the extinction of many species 65 million years ago

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Alvarez, L.W.

    1982-09-01

    The development of the theory that the mass extinction of the dinosaurs at the Cretaceous-Tertiary boundary was caused by an asteroid impact is reviewed. The personnel involved, the objections to the theory, and the evidence refuting those objections are presented chronologically. (ACR)

  6. Shrub growth and expansion in the Arctic tundra: an assessment of controlling factors using an evidence-based approach

    NASA Astrophysics Data System (ADS)

    Martin, Andrew C.; Jeffers, Elizabeth S.; Petrokofsky, Gillian; Myers-Smith, Isla; Macias-Fauria, Marc

    2017-08-01

    Woody shrubs have increased in biomass and expanded into new areas throughout the Pan-Arctic tundra biome in recent decades, which has been linked to a biome-wide observed increase in productivity. Experimental, observational, and socio-ecological research suggests that air temperature—and to a lesser degree precipitation—trends have been the predominant drivers of this change. However, a progressive decoupling of these drivers from Arctic vegetation productivity has been reported, and since 2010, vegetation productivity has also been declining. We created a protocol to (a) identify the suite of controls that may be operating on shrub growth and expansion, and (b) characterise the evidence base for controls on Arctic shrub growth and expansion. We found evidence for a suite of 23 proximal controls that operate directly on shrub growth and expansion; the evidence base focused predominantly on just four controls (air temperature, soil moisture, herbivory, and snow dynamics). 65% of evidence was generated in the warmest tundra climes, while 24% was from only one of 28 floristic sectors. Temporal limitations beyond 10 years existed for most controls, while the use of space-for-time approaches was high, with 14% of the evidence derived via experimental approaches. The findings suggest the current evidence base is not sufficiently robust or comprehensive at present to answer key questions of Pan-Arctic shrub change. We suggest future directions that could strengthen the evidence, and lead to an understanding of the key mechanisms driving changes in Arctic shrub environments.

  7. Evidence of multipolar response of Bacteriorhodopsin by noncollinear second harmonic generation.

    PubMed

    Bovino, F A; Larciprete, M C; Sibilia, C; Váró, G; Gergely, C

    2012-06-18

    Noncollinear second harmonic generation from a Bacteriorhodopsin (BR) oriented multilayer film was systematically investigated by varying the polarization state of both fundamental beams. Both experimental results and theoretical simulations, show that the resulting polarization mapping is an useful tool to put in evidence the optical chirality of the investigated film as well as the corresponding multipolar contributions to the nonlinear.

  8. Optimal decision making on the basis of evidence represented in spike trains.

    PubMed

    Zhang, Jiaxiang; Bogacz, Rafal

    2010-05-01

    Experimental data indicate that perceptual decision making involves integration of sensory evidence in certain cortical areas. Theoretical studies have proposed that the computation in neural decision circuits approximates statistically optimal decision procedures (e.g., sequential probability ratio test) that maximize the reward rate in sequential choice tasks. However, these previous studies assumed that the sensory evidence was represented by continuous values from gaussian distributions with the same variance across alternatives. In this article, we make a more realistic assumption that sensory evidence is represented in spike trains described by the Poisson processes, which naturally satisfy the mean-variance relationship observed in sensory neurons. We show that for such a representation, the neural circuits involving cortical integrators and basal ganglia can approximate the optimal decision procedures for two and multiple alternative choice tasks.

  9. Evidence-based Kernels: Fundamental Units of Behavioral Influence

    PubMed Central

    Biglan, Anthony

    2008-01-01

    This paper describes evidence-based kernels, fundamental units of behavioral influence that appear to underlie effective prevention and treatment for children, adults, and families. A kernel is a behavior–influence procedure shown through experimental analysis to affect a specific behavior and that is indivisible in the sense that removing any of its components would render it inert. Existing evidence shows that a variety of kernels can influence behavior in context, and some evidence suggests that frequent use or sufficient use of some kernels may produce longer lasting behavioral shifts. The analysis of kernels could contribute to an empirically based theory of behavioral influence, augment existing prevention or treatment efforts, facilitate the dissemination of effective prevention and treatment practices, clarify the active ingredients in existing interventions, and contribute to efficiently developing interventions that are more effective. Kernels involve one or more of the following mechanisms of behavior influence: reinforcement, altering antecedents, changing verbal relational responding, or changing physiological states directly. The paper describes 52 of these kernels, and details practical, theoretical, and research implications, including calling for a national database of kernels that influence human behavior. PMID:18712600

  10. Theoretical and experimental evidence of level repulsion states and evanescent modes in sonic crystal stubbed waveguides

    NASA Astrophysics Data System (ADS)

    Romero-García, V.; Vasseur, J. O.; Garcia-Raffi, L. M.; Hladky-Hennion, A. C.

    2012-02-01

    The complex band structures calculated using the extended plane wave expansion (EPWE) reveal the presence of evanescent modes in periodic systems, never predicted by the classical \\omega(\\vec {k}) methods, providing novel interpretations of several phenomena as well as a complete picture of the system. In this work, we theoretically and experimentally observe that in the ranges of frequencies where a deaf band is traditionally predicted, an evanescent mode with excitable symmetry appears, changing drastically the interpretation of the transmission properties. On the other hand, the simplicity of the sonic crystals in which only the longitudinal polarization can be excited is used to interpret, without loss of generality, the level repulsion between symmetric and antisymmetric bands in sonic crystals as the presence of an evanescent mode connecting both repelled bands. These evanescent modes, obtained using EPWE, explain both the attenuation produced in this range of frequencies and the transfer of symmetry from one band to the other in good agreement with both experimental results and multiple scattering predictions. Thus, the evanescent properties of the periodic system have been revealed to be necessary for the design of new acoustic and electromagnetic applications based on periodicity.

  11. Sex, Gender, and Pain: A Review of Recent Clinical and Experimental Findings

    PubMed Central

    Fillingim, Roger B.; King, Christopher D.; Ribeiro-Dasilva, Margarete C.; Rahim-Williams, Bridgett; Riley, Joseph L.

    2009-01-01

    Sex-related influences on pain and analgesia have become a topic of tremendous scientific and clinical interest, especially in the last 10 to 15 years. Members of our research group published reviews of this literature more than a decade ago, and the intervening time period has witnessed robust growth in research regarding sex, gender, and pain. Therefore, it seems timely to revisit this literature. Abundant evidence from recent epidemiologic studies clearly demonstrates that women are at substantially greater risk for many clinical pain conditions, and there is some suggestion that postoperative and procedural pain may be more severe among women than men. Consistent with our previous reviews, current human findings regarding sex differences in experimental pain indicate greater pain sensitivity among females compared with males for most pain modalities, including more recently implemented clinically relevant pain models such as temporal summation of pain and intramuscular injection of algesic substances. The evidence regarding sex differences in laboratory measures of endogenous pain modulation is mixed, as are findings from studies using functional brain imaging to ascertain sex differences in pain-related cerebral activation. Also inconsistent are findings regarding sex differences in responses to pharmacologic and non-pharmacologic pain treatments. The article concludes with a discussion of potential biopsychosocial mechanisms that may underlie sex differences in pain, and considerations for future research are discussed. Perspective This article reviews the recent literature regarding sex, gender, and pain. The growing body of evidence that has accumulated in the past 10 to 15 years continues to indicate substantial sex differences in clinical and experimental pain responses, and some evidence suggests that pain treatment responses may differ for women versus men. PMID:19411059

  12. Medication-assisted treatment with methadone: assessing the evidence.

    PubMed

    Fullerton, Catherine Anne; Kim, Meelee; Thomas, Cindy Parks; Lyman, D Russell; Montejano, Leslie B; Dougherty, Richard H; Daniels, Allen S; Ghose, Sushmita Shoma; Delphin-Rittmon, Miriam E

    2014-02-01

    Detoxification followed by abstinence has shown little success in reducing illicit opioid use. Methadone maintenance treatment (MMT) helps individuals with an opioid use disorder abstain from or decrease use of illegal or nonmedical opiates. This review examined evidence for MMT's effectiveness. Authors reviewed meta-analyses, systematic reviews, and individual studies of MMT from 1995 through 2012. Databases searched were PubMed, PsycINFO, Applied Social Sciences Index and Abstracts, Sociological Abstracts, Social Services Abstracts, and Published International Literature on Traumatic Stress. The authors rated the level of evidence (high, moderate, and low) based on benchmarks for the number of studies and quality of their methodology. They also described the evidence of service effectiveness and examined maternal and fetal results of MMT for pregnant women. The review included seven randomized controlled trials and two quasi-experimental studies of MMT, indicating a high level of evidence for the positive impact of MMT on treatment retention and illicit opioid use, particularly at doses greater than 60 mg. Evidence suggests positive impacts on drug-related HIV risk behaviors, mortality, and criminality. Meta-analyses were difficult to perform or yielded nonsignificant results. Studies found little association between MMT and sex-related HIV risk behaviors. MMT in pregnancy was associated with improved maternal and fetal outcomes, and rates of neonatal abstinence syndrome were similar for mothers receiving different doses. Reports of adverse events were also found. MMT is associated with improved outcomes for individuals and pregnant women with opioid use disorders. MMT should be a covered service available to all individuals.

  13. Plain packaging of cigarettes: do we have sufficient evidence?

    PubMed Central

    Smith, Collin N; Kraemer, John D; Johnson, Andrea C; Mays, Darren

    2015-01-01

    Tobacco industry marketing is a primary factor influencing cigarette smoking behavior and the cigarette pack has become an important marketing vehicle for tobacco companies. Standardized “plain” cigarette packaging is advocated as a public health policy to prevent and reduce morbidity and mortality caused by smoking by reducing youth smoking initiation and promoting cessation among smokers. Plain packaging was implemented in Australia in December 2012, and several other countries are considering doing so, but each faces foreseeable legal resistance from opponents to such measures. Tobacco companies have challenged these public health policies, citing international trade agreements and intellectual property laws. Decision-making in these court cases will hinge in part on whether the evidence indicates the public health benefits of plain packaging outweigh any potential harm to tobacco manufacturers’ interests. We reviewed the available evidence in support of plain packaging, finding evidence from observational, experimental, and population-based studies. Results indicate that plain packaging can reduce positive perceptions of smoking and dissuade tobacco use. Governments deciding to implement plain cigarette packaging measures can rely on this evidence to help make a strong case that plain packaging plays an important role in the context of comprehensive smoking prevention efforts. PMID:25897269

  14. Evidence of Adaptive Evolutionary Divergence during Biological Invasion

    PubMed Central

    Lucek, Kay; Sivasundar, Arjun; Seehausen, Ole

    2012-01-01

    Rapid phenotypic diversification during biological invasions can either arise by adaptation to alternative environments or by adaptive phenotypic plasticity. Where experimental evidence for adaptive plasticity is common, support for evolutionary diversification is rare. Here, we performed a controlled laboratory experiment using full-sib crosses between ecologically divergent threespine stickleback populations to test for a genetic basis of adaptation. Our populations are from two very different habitats, lake and stream, of a recently invaded range in Switzerland and differ in ecologically relevant morphological traits. We found that in a lake-like food treatment lake fish grow faster than stream fish, resembling the difference among wild type individuals. In contrast, in a stream-like food treatment individuals from both populations grow similarly. Our experimental data suggest that genetically determined diversification has occurred within less than 140 years after the arrival of stickleback in our studied region. PMID:23152900

  15. Effects of an evidence service on health-system policy makers' use of research evidence: a protocol for a randomised controlled trial.

    PubMed

    Lavis, John N; Wilson, Michael G; Grimshaw, Jeremy M; Haynes, R Brian; Hanna, Steven; Raina, Parminder; Gruen, Russell; Ouimet, Mathieu

    2011-05-27

    Health-system policy makers need timely access to synthesised research evidence to inform the policy-making process. No efforts to address this need have been evaluated using an experimental quantitative design. We developed an evidence service that draws inputs from Health Systems Evidence, which is a database of policy-relevant systematic reviews. The reviews have been (a) categorised by topic and type of review; (b) coded by the last year searches for studies were conducted and by the countries in which included studies were conducted; (c) rated for quality; and (d) linked to available user-friendly summaries, scientific abstracts, and full-text reports. Our goal is to evaluate whether a "full-serve" evidence service increases the use of synthesized research evidence by policy analysts and advisors in the Ontario Ministry of Health and Long-Term Care (MOHLTC) as compared to a "self-serve" evidence service. We will conduct a two-arm randomized controlled trial (RCT), along with a follow-up qualitative process study in order to explore the findings in greater depth. For the RCT, all policy analysts and policy advisors (n = 168) in a single division of the MOHLTC will be invited to participate. Using a stratified randomized design, participants will be randomized to receive either the "full-serve" evidence service (database access, monthly e-mail alerts, and full-text article availability) or the "self-serve" evidence service (database access only). The trial duration will be ten months (two-month baseline period, six-month intervention period, and two month cross-over period). The primary outcome will be the mean number of site visits/month/user between baseline and the end of the intervention period. The secondary outcome will be participants' intention to use research evidence. For the qualitative study, 15 participants from each trial arm (n = 30) will be purposively sampled. One-on-one semi-structured interviews will be conducted by telephone on their views

  16. Effects of an evidence service on health-system policy makers' use of research evidence: A protocol for a randomised controlled trial

    PubMed Central

    2011-01-01

    Background Health-system policy makers need timely access to synthesised research evidence to inform the policy-making process. No efforts to address this need have been evaluated using an experimental quantitative design. We developed an evidence service that draws inputs from Health Systems Evidence, which is a database of policy-relevant systematic reviews. The reviews have been (a) categorised by topic and type of review; (b) coded by the last year searches for studies were conducted and by the countries in which included studies were conducted; (c) rated for quality; and (d) linked to available user-friendly summaries, scientific abstracts, and full-text reports. Our goal is to evaluate whether a "full-serve" evidence service increases the use of synthesized research evidence by policy analysts and advisors in the Ontario Ministry of Health and Long-Term Care (MOHLTC) as compared to a "self-serve" evidence service. Methods/design We will conduct a two-arm randomized controlled trial (RCT), along with a follow-up qualitative process study in order to explore the findings in greater depth. For the RCT, all policy analysts and policy advisors (n = 168) in a single division of the MOHLTC will be invited to participate. Using a stratified randomized design, participants will be randomized to receive either the "full-serve" evidence service (database access, monthly e-mail alerts, and full-text article availability) or the "self-serve" evidence service (database access only). The trial duration will be ten months (two-month baseline period, six-month intervention period, and two month cross-over period). The primary outcome will be the mean number of site visits/month/user between baseline and the end of the intervention period. The secondary outcome will be participants' intention to use research evidence. For the qualitative study, 15 participants from each trial arm (n = 30) will be purposively sampled. One-on-one semi-structured interviews will be conducted by

  17. Placebo analgesia is not due to compliance or habituation: EEG and behavioural evidence.

    PubMed

    Watson, Alison; El-Deredy, Wael; Vogt, Brent A; Jones, Anthony K P

    2007-05-28

    This study was designed to resolve whether experimental placebo responses are due to either increased compliance or habituation. We stimulated both forearms and recorded laser-evoked potentials from 18 healthy volunteers treated on one arm with a sham analgesic cream and an inactive cream on the other (treatment group), and 13 volunteers with an inactive cream on both arms (controls). The treatment group showed a significant reduction in the pain ratings and laser-evoked potentials with both the sham and inactive creams. The control group showed no evidence of habituation to the laser stimulus. The results indicate that the reduction in pain during experimental placebo response is unlikely to be due to sensory habituation or compliance with the experimental instructions.

  18. A spotlight on liquefaction: evidence from clinical settings and experimental models in tuberculosis.

    PubMed

    Cardona, Pere-Joan

    2011-01-01

    Liquefaction is one of the most intriguing aspects of human tuberculosis. It is a major cause of the transition from the infection to active disease (tuberculosis, TB) as well as the transmission of M. tuberculosis to other persons. This paper reviews the natural history of liquefaction in humans from a pathological and radiological point of view and discusses how the experimental models available can be used to address the topic of liquefaction and cavity formation. Different concepts that have been related to liquefaction, from the influence of immune response to mechanical factors, are reviewed. Synchronic necrosis or apoptosis of infected macrophages in a close area, together with an ineffective fibrosis, appears to be clue in this process, in which macrophages, the immune response, and bacillary load interact usually in a particular scenario: the upper lobes of the lung. The summary would be that even if being a stochastic effect, liquefaction would result if the organization of the intragranulomatous necrosis (by means of fibrosis) would be disturbed.

  19. A systematic review of the evidence concerning the economic impact of employee-focused health promotion and wellness programs.

    PubMed

    Lerner, Debra; Rodday, Angie Mae; Cohen, Joshua T; Rogers, William H

    2013-02-01

    To assess the evidence regarding the economic impact of worker health promotion programs. Peer-reviewed research articles were identified from a database search. Included articles were published between January 2000 and May 2010, described a study conducted in the United States that used an experimental or quasi-experimental study design and analyzed medical, pharmacy (direct), and/or work productivity (indirect) costs. A multidisciplinary review team, following specific criteria, assessed research quality. Of 2030 retrieved articles, 44 met study inclusion criteria. Of these, 10 were of sufficient quality to be considered evidentiary. Only three analyzed direct and indirect costs. Evidence regarding economic impact is limited and inconsistent. Higher-quality research is needed to demonstrate the value of specific programs.

  20. 6. "EXPERIMENTAL ROCKET ENGINE TEST STATION AT AFFTC." A low ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. "EXPERIMENTAL ROCKET ENGINE TEST STATION AT AFFTC." A low oblique aerial view of Test Area 1-115, looking south, showing Test Stand 1-3 at left, Instrumentation and Control building 8668 at center, and Test Stand 15 at right. The test area is under construction; no evidence of railroad line in photo. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Leuhman Ridge near Highways 58 & 395, Boron, Kern County, CA

  1. [Evidence and Evidence Gaps - an Introduction].

    PubMed

    Dreier, G; Löhler, J

    2016-04-01

    Treating patients requires the inclusion of existing evidence in any health care decision, to be able to choose the best diagnosis or treatment measure or to make valid prognosis statements for a particular patient in consideration of the physician's own expertise.The basis are clinical trials, the results of which are ideally gathered in systematic reviews, rated, summarized and published. In addition to the GCP (Good Clinical Practice)-compliant planning, conducting and analysis of clinical studies it is essential, that all study results are made publicly available, in order to avoid publication bias. This includes the public registration of planned and discontinued trials. In the last 25 years, the evidence-based medicine (EbM) has increasingly found its way into clinical practice and research. Here EbM is closely associated with the names Archibald Cochrane and David Sackett. In Germany, both the German Cochrane Centre (DCZ) and the network of evidence-based medicine (DNEbM) were established approximately 15 years ago. In the international Cochrane Collaboration clinicians and other scientists like statisticians interdisciplinary work side by side to develop the methods of evidence-based medicine and to address the topics of evidence generation and processing as well as the transfer of knowledge. Challenge: Existing evidence primarily serves doctors to support their decision-making, but is also the basis for providing scientific proof for a health care intervention's benefit to patients and ultimately payers/health insurances. The closure of existing evidence gaps requires substantial human and financial resources, a complex organizational structure and can only succeed with the involvement of clinical and methodological expertise and specific knowledge in the field of clinical research. In addition, the knowledge must be transferred into practice, using journals, guidelines, conferences, databases, information portals with processed evidence and not least the

  2. Incretin-Based Therapies for Diabetic Complications: Basic Mechanisms and Clinical Evidence

    PubMed Central

    Kawanami, Daiji; Matoba, Keiichiro; Sango, Kazunori; Utsunomiya, Kazunori

    2016-01-01

    An increase in the rates of morbidity and mortality associated with diabetic complications is a global concern. Glycemic control is important to prevent the development and progression of diabetic complications. Various classes of anti-diabetic agents are currently available, and their pleiotropic effects on diabetic complications have been investigated. Incretin-based therapies such as dipeptidyl peptidase (DPP)-4 inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1RA) are now widely used in the treatment of patients with type 2 diabetes. A series of experimental studies showed that incretin-based therapies have beneficial effects on diabetic complications, independent of their glucose-lowering abilities, which are mediated by anti-inflammatory and anti-oxidative stress properties. Based on these findings, clinical studies to assess the effects of DPP-4 inhibitors and GLP-1RA on diabetic microvascular and macrovascular complications have been performed. Several but not all studies have provided evidence to support the beneficial effects of incretin-based therapies on diabetic complications in patients with type 2 diabetes. We herein discuss the experimental and clinical evidence of incretin-based therapy for diabetic complications. PMID:27483245

  3. The essential value of long-term experimental data for hydrology and water management

    NASA Astrophysics Data System (ADS)

    Tetzlaff, Doerthe; Carey, Sean K.; McNamara, James P.; Laudon, Hjalmar; Soulsby, Chris

    2017-04-01

    Observations and data from long-term experimental watersheds are the foundation of hydrology as a geoscience. They allow us to benchmark process understanding, observe trends and natural cycles, and are prerequisites for testing predictive models. Long-term experimental watersheds also are places where new measurement technologies are developed. These studies offer a crucial evidence base for understanding and managing the provision of clean water supplies, predicting and mitigating the effects of floods, and protecting ecosystem services provided by rivers and wetlands. They also show how to manage land and water in an integrated, sustainable way that reduces environmental and economic costs.

  4. Efficacy of an Evidence-Based Literacy Preparation Program for Young Children Beginning School

    ERIC Educational Resources Information Center

    Wheldall, Robyn; Glenn, Katharine; Arakelian, Sarah; Madelaine, Alison; Reynolds, Meree; Wheldall, Kevin

    2016-01-01

    This study aimed to provide evidence regarding the efficacy of an early literacy preparation program, "PreLit", designed to improve the skills of young Australian children. Participants comprised 240 children in eight schools attending their first year of schooling. Children in the four experimental group schools received instruction in…

  5. Evidence for a regime shift in nitrogen export from a forested watershed

    Treesearch

    J. R. Webster; Jennifer Knoepp; Wayne Swank; Chelcy Miniat

    2016-01-01

    In this study, we document a functional regime shift in stream inorganic nitrogen (N) processing indicated by a major change in N export from a forested watershed. Evidence from 36 years of data following experimental clearcut logging at Coweeta Hydrologic Laboratory, NC, suggests that forest disturbance in this area can cause elevation of dissolved inorganic...

  6. Enhancing (In)Formal Learning Ties in Interdisciplinary Management Courses: A Quasi-Experimental Social Network Study

    ERIC Educational Resources Information Center

    Rienties, Bart; Héliot, YingFei

    2018-01-01

    While interdisciplinary courses are regarded as a promising method for students to learn and apply knowledge from other disciplines, there is limited empirical evidence available whether interdisciplinary courses can effectively "create" interdisciplinary students. In this innovative quasi-experimental study amongst 377 Master's…

  7. School-based obesity prevention programs: an evidence-based review.

    PubMed

    Kropski, Jonathan A; Keckley, Paul H; Jensen, Gordon L

    2008-05-01

    This review seeks to examine the effectiveness of school-based programs for reducing childhood overweight or obesity. A systematic review of the research literature published since 1990 was conducted to identify experimental or quasi-experimental school-based curricular or environmental preventive interventions, with evaluation>or=6 months after baseline, which reported outcomes in terms of a measure of overweight. Fourteen studies were identified, including one involving a nutrition-only program, two physical activity promotion interventions and eleven studies combining nutrition and physical activity components. Most studies (n=10) offered weak (grade 2) quality evidence. One study offered strong (grade 4) evidence reducing the odds ratio for overweight in girls only, while four grade 2 studies reported significant improvements in BMI or at-risk-for overweight or overweight prevalence in boys, girls, or both. Twelve studies reported significant improvement in at least one measure of dietary intake, physical activity, and/or sedentary behavior. Our ability to draw strong conclusions as to the efficacy of school-based obesity prevention programs is limited by the small number of published studies and by methodological concerns. Qualitative analysis suggests programs grounded in social learning may be more appropriate for girls, while structural and environmental interventions enabling physical activity may be more effective for boys. High-quality evaluation protocols should be considered essential components of future programs.

  8. Experimental evolution reveals hidden diversity in evolutionary pathways.

    PubMed

    Lind, Peter A; Farr, Andrew D; Rainey, Paul B

    2015-03-25

    Replicate populations of natural and experimental organisms often show evidence of parallel genetic evolution, but the causes are unclear. The wrinkly spreader morph of Pseudomonas fluorescens arises repeatedly during experimental evolution. The mutational causes reside exclusively within three pathways. By eliminating these, 13 new mutational pathways were discovered with the newly arising WS types having fitnesses similar to those arising from the commonly passaged routes. Our findings show that parallel genetic evolution is strongly biased by constraints and we reveal the genetic bases. From such knowledge, and in instances where new phenotypes arise via gene activation, we suggest a set of principles: evolution proceeds firstly via pathways subject to negative regulation, then via promoter mutations and gene fusions, and finally via activation by intragenic gain-of-function mutations. These principles inform evolutionary forecasting and have relevance to interpreting the diverse array of mutations associated with clinically identical instances of disease in humans.

  9. Experimental evolution reveals hidden diversity in evolutionary pathways

    PubMed Central

    Lind, Peter A; Farr, Andrew D; Rainey, Paul B

    2015-01-01

    Replicate populations of natural and experimental organisms often show evidence of parallel genetic evolution, but the causes are unclear. The wrinkly spreader morph of Pseudomonas fluorescens arises repeatedly during experimental evolution. The mutational causes reside exclusively within three pathways. By eliminating these, 13 new mutational pathways were discovered with the newly arising WS types having fitnesses similar to those arising from the commonly passaged routes. Our findings show that parallel genetic evolution is strongly biased by constraints and we reveal the genetic bases. From such knowledge, and in instances where new phenotypes arise via gene activation, we suggest a set of principles: evolution proceeds firstly via pathways subject to negative regulation, then via promoter mutations and gene fusions, and finally via activation by intragenic gain-of-function mutations. These principles inform evolutionary forecasting and have relevance to interpreting the diverse array of mutations associated with clinically identical instances of disease in humans. DOI: http://dx.doi.org/10.7554/eLife.07074.001 PMID:25806684

  10. Evidence based practice in long term care settings.

    PubMed

    Specht, Janet K

    2013-04-01

    The purpose of this manuscript is to discuss the need for use of evidence based practice (EBP) in LTC, the current use of evidence in long term care facilities and what we know about adoption of the use of EBP in LTC. Literature review and reporting of findings from the M-TRAIN study that was a quasi-experimental design to test the effectiveness of an intervention to increase the use of EBPs for urinary incontinence and pain in 48 LTC facilities. Barriers to adopting EBPs include lack of available time, lack of access to current research literature, limited critical appraisal skills, excessive literature to review, non-receptive organizational culture, limited resources, and limited decision-making authority of staff to implement change. Strategies to promote adoption of EBP include the commitment of management; the culture of the home; leadership; staff knowledge, time, and reward; and facility size, complexity, the extent that members are involved outside the facility, NH chain membership, and high level of private pay residents. Findings from the M-TRAIN add, stability of nurse leader and congruency between the leaders perception of their leadership and the staff's perception of the leadership. There is clear evidence of the need and the benefits to residents of LTC and to the health care system yet adoption of EBP continues to be slow and sporadic. There is also evidence for the process of establishing best evidence and many resources to find the available EBPs. The urgent need now is finding ways to best get the EBPs implemented in LTC. There is growing evidence about best methods to do this but continued research is needed. Clearly, residents in LTC deserve the best care possible and EBPs represent an important vehicle by which to do this.

  11. Evidence-based medicine and big genomic data.

    PubMed

    Ioannidis, John P A; Khoury, Muin J

    2018-05-01

    Genomic and other related big data (Big Genomic Data, BGD for short) are ushering a new era of precision medicine. This overview discusses whether principles of evidence-based medicine hold true for BGD and how they should be operationalized in the current era. Major evidence-based medicine principles include the systematic identification, description and analysis of the validity and utility of BGD, the combination of individual clinical expertise with individual patient needs and preferences, and the focus on obtaining experimental evidence, whenever possible. BGD emphasize information of single patients with an overemphasis on N-of-1 trials to personalize treatment. However, large-scale comparative population data remain indispensable for meaningful translation of BGD personalized information. The impact of BGD on population health depends on its ability to affect large segments of the population. While several frameworks have been proposed to facilitate and standardize decision making for use of genomic tests, there are new caveats that arise from BGD that extend beyond the limitations that were applicable for more simple genetic tests. Non-evidence-based use of BGD may be harmful and result in major waste of healthcare resources. Randomized controlled trials will continue to be the strongest arbitrator for the clinical utility of genomic technologies, including BGD. Research on BGD needs to focus not only on finding robust predictive associations (clinical validity) but also more importantly on evaluating the balance of health benefits and potential harms (clinical utility), as well as implementation challenges. Appropriate features of such useful research on BGD are discussed.

  12. Multiple deleterious effects of experimentally aged sperm in a monogamous bird

    USGS Publications Warehouse

    White, J.; Wagner, R.H.; Helfenstein, F.; Hatch, Shyla A.; Mulard, Hervé; Naves, L.C.; Danchin, E.

    2008-01-01

    Sperm aging is known to be detrimental to reproductive performance. However, this apparently general phenomenon has seldom been studied in an evolutionary context. The negative impact of sperm aging on parental fitness should constitute a strong selective pressure for adaptations to avoid its effects. We studied the impact of sperm aging on black-legged kittiwakes (Rissa tridactyla), a monogamous seabird. Kittiwakes comprise a model system because (i) of evidence that females eject their mates' sperm to prevent fertilization by sperm that would be old and degraded by the time of fertilization and result in reduced reproductive performance and (ii) the lack of extra-pair fertilization in this species makes cryptic female choice an unlikely explanation of postcopulatory sperm ejection by females. We experimentally manipulated the age of the sperm fertilizing kittiwake eggs by fitting males with anti-insemination rings for variable periods of time preceding egg-laying. We found evidence that sperm aging negatively affected four sequential stages of reproduction: fertilization potential, rate of embryonic development, embryonic mortality, and chick condition at hatching. These results may be produced by a continuum of a single process of sperm aging that differentially affects various aspects of development, depending on the degree of damage incurred to the spermatozoa. The marked impact of sperm age on female fitness may thus drive postcopulatory sperm ejection by females. These results provide experimental evidence of deleterious effects of sperm aging on a nondomestic vertebrate, underlining its taxonomic generality and its potential to select for a wide array of adaptations. ?? 2008 by The National Academy of Sciences of the USA.

  13. Effects of Physical Activity on Children’s Executive Function: Contributions of Experimental Research on Aerobic Exercise

    PubMed Central

    Best, John R.

    2011-01-01

    Executive function refers to the cognitive processes necessary for goal-directed cognition and behavior, which develop across childhood and adolescence. Recent experimental research indicates that both acute and chronic aerobic exercise promote children’s executive function. Furthermore, there is tentative evidence that not all forms of aerobic exercise benefit executive function equally: Cognitively-engaging exercise appears to have a stronger effect than non-engaging exercise on children’s executive function. This review discusses this evidence as well as the mechanisms that may underlie the association between exercise and executive function. Research from a variety of disciplines is covered, including developmental psychology, kinesiology, cognitive neuroscience, and biopsychology. Finally, these experimental findings are placed within the larger context of known links between action and cognition in infancy and early childhood, and the clinical and practical implications of this research are discussed. PMID:21818169

  14. Assessing students' ability to critically evaluate evidence in an inquiry-based undergraduate laboratory course.

    PubMed

    Colthorpe, Kay; Mehari Abraha, Hyab; Zimbardi, Kirsten; Ainscough, Louise; Spiers, Jereme G; Chen, Hsiao-Jou Cortina; Lavidis, Nickolas A

    2017-03-01

    The ability to critically evaluate and use evidence from one's own work or from primary literature is invaluable to any researcher. These skills include the ability to identify strengths and weakness of primary literature, to gauge the impact of research findings on a field, to identify gaps in a field that require more research, and to contextualize findings within a field. This study developed a model to examine undergraduate science students' abilities to critically evaluate and use evidence through an analysis of laboratory reports from control and experimental groups in nonresearch-aligned and research-aligned inquiry-based laboratory classes, respectively, and contrasted these with published scientific research articles. The reports analyzed ( n = 42) showed that students used evidence in a variety of ways, most often referring to literature indirectly, and least commonly highlighting limitations of literature. There were significant positive correlations between grade awarded and the use of references, evidence, and length, but there were no significant differences between control and experimental groups, so data were pooled. The use of evidence in scientific research articles ( n = 7) was similar to student reports except that expert authors were more likely to refer to their own results and cite more references. Analysis showed that students, by the completion of the second year of their undergraduate degree, had expertise approaching that of published authors. These findings demonstrate that it is possible to provide valuable broad-scale undergraduate research experiences to all students in a cohort, giving them exposure to the methods and communication processes of research as well as an opportunity to hone their critical evaluation skills. Copyright © 2017 the American Physiological Society.

  15. [The 1, 2, 3 of laboratory animal experimentation].

    PubMed

    Romero-Fernandez, Wilber; Batista-Castro, Zenia; De Lucca, Marisel; Ruano, Ana; García-Barceló, María; Rivera-Cervantes, Marta; García-Rodríguez, Julio; Sánchez-Mateos, Soledad

    2016-06-01

    The slow scientific development in Latin America in recent decades has delayed the incorporation of laboratory animal experimentation; however, this situation has started to change. Today, extraordinary scientific progress is evident, which has promoted the introduction and increased use of laboratory animals as an important tool for the advancement of biomedical sciences. In the aftermath of this boom, the need to provide the scientific community with training and guidance in all aspects related to animal experimentation has arisen. It is the responsibility of each country to regulate this practice, for both bioethical and legal reasons, to ensure consideration of the animals' rights and welfare. The following manuscript is the result of papers presented at the International Workshop on Laboratory Animal Testing held at the Technical University of Ambato, Ecuador; it contains information regarding the current state of affairs in laboratory animal testing and emphasizes critical aspects such as main species used, ethical and legal principles, and experimental and alternative designs for animal use. These works aim to ensure good practices that should define scientific work. This document will be relevant to both researchers who aim to newly incorporate animal testing into their research and those who seek to update their knowledge.

  16. Designing Incentives for Public School Teachers: Evidence from a Texas Incentive Pay Program

    ERIC Educational Resources Information Center

    Springer, Matthew G.; Taylor, Lori L.

    2016-01-01

    Pay-for-performance is a popular public education reform, but there is little evidence about the characteristics of a well-designed incentive pay plan for teachers. Some of the literature suggests that effective incentive plans must offer relatively large awards to induce behavioral changes. On the other hand, the experimental economics literature…

  17. Evidence and evidence gaps in tinnitus therapy

    PubMed Central

    Hesse, Gerhard

    2016-01-01

    A nearly endless number of procedures has been tried and in particular sold for the treatment of tinnitus, unfortunately they have not been evaluated appropriately in an evidence-based way. A causal therapy, omitting the tinnitus still does not exist, actually it cannot exist because of the various mechanisms of its origin. However or perhaps because of that, medical interventions appear and reappear like fashion trends that can never be proven by stable and reliable treatment success. This contribution will discuss and acknowledge all current therapeutic procedures and the existing or non-existing evidence will be assessed. Beside external evidence, the term of evidence also encompasses the internal evidence, i.e. the experience of the treating physician and the patient’s needs shall be included. While there is no evidence for nearly all direct procedures that intend modulating or stimulating either the cochlea or specific cervical regions such as the auditory cortex, there are therapeutic procedures that are acknowledged in clinical practice and have achieved at least a certain degree of evidence and generate measurable effect sizes. Those are in particular habituation therapy and psychotherapeutic measures, especially if they are combined with concrete measures for improved audio perception (hearing aids, CI, hearing therapies). PMID:28025604

  18. Experimental evidences for reducing Mg activation energy in high Al-content AlGaN alloy by MgGa δ doping in (AlN)m/(GaN)n superlattice

    PubMed Central

    Wang, Xiao; Wang, Wei; Wang, Jingli; Wu, Hao; Liu, Chang

    2017-01-01

    P-type doping in high Al-content AlGaN alloys is a main challenge for realizing AlGaN-based deep ultraviolet optoelectronics devices. According to the first-principles calculations, Mg activation energy may be reduced so that a high hole concentration can be obtained by introducing nanoscale (AlN)5/(GaN)1 superlattice (SL) in Al0.83Ga0.17N disorder alloy. In this work, experimental evidences were achieved by analyzing Mg doped high Al-content AlGaN alloys and Mg doped AlGaN SLs as well as MgGa δ doped AlGaN SLs. Mg acceptor activation energy was significantly reduced from 0.378 to 0.331 eV by using MgGa δ doping in SLs instead of traditional doping in alloys. This new process was confirmed to be able to realize high p-type doping in high Al-content AlGaN. PMID:28290480

  19. Experimental evidences for reducing Mg activation energy in high Al-content AlGaN alloy by MgGa δ doping in (AlN)m/(GaN)n superlattice

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Wang, Wei; Wang, Jingli; Wu, Hao; Liu, Chang

    2017-03-01

    P-type doping in high Al-content AlGaN alloys is a main challenge for realizing AlGaN-based deep ultraviolet optoelectronics devices. According to the first-principles calculations, Mg activation energy may be reduced so that a high hole concentration can be obtained by introducing nanoscale (AlN)5/(GaN)1 superlattice (SL) in Al0.83Ga0.17N disorder alloy. In this work, experimental evidences were achieved by analyzing Mg doped high Al-content AlGaN alloys and Mg doped AlGaN SLs as well as MgGa δ doped AlGaN SLs. Mg acceptor activation energy was significantly reduced from 0.378 to 0.331 eV by using MgGa δ doping in SLs instead of traditional doping in alloys. This new process was confirmed to be able to realize high p-type doping in high Al-content AlGaN.

  20. Experimental evidences for reducing Mg activation energy in high Al-content AlGaN alloy by MgGa δ doping in (AlN)m/(GaN)n superlattice.

    PubMed

    Wang, Xiao; Wang, Wei; Wang, Jingli; Wu, Hao; Liu, Chang

    2017-03-14

    P-type doping in high Al-content AlGaN alloys is a main challenge for realizing AlGaN-based deep ultraviolet optoelectronics devices. According to the first-principles calculations, Mg activation energy may be reduced so that a high hole concentration can be obtained by introducing nanoscale (AlN) 5 /(GaN) 1 superlattice (SL) in Al 0.83 Ga 0.17 N disorder alloy. In this work, experimental evidences were achieved by analyzing Mg doped high Al-content AlGaN alloys and Mg doped AlGaN SLs as well as Mg Ga δ doped AlGaN SLs. Mg acceptor activation energy was significantly reduced from 0.378 to 0.331 eV by using Mg Ga δ doping in SLs instead of traditional doping in alloys. This new process was confirmed to be able to realize high p-type doping in high Al-content AlGaN.