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Sample records for experimental evidence indicating

  1. 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…

  2. 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…

  3. Reanalysis and experimental evidence indicate that the earliest trace fossil of a winged insect was a surface-skimming neopteran.

    PubMed

    Marden, James H

    2013-01-01

    A recent description and analysis of an imprint fossil from the Carboniferous concluded that it was made by a mayfly landing in sediment at the edge of water. Here, I reanalyze that trace fossil and supply experimental evidence regarding wing traces and behavior. The thorax of the trace maker lacked structures characteristic of mayflies, but closely matches a modern neopteran insect family (Taeniopterygidae, Plecoptera) little changed from Early Permian fossils. Edges of the folded wings of live Taeniopteryx leave marks on sediment closely matching marks in the trace fossil. Faint marks lateral to and beyond the reach of meso- and metathoracic legs match the location where wings of surface-skimming Taeniopteryx stoneflies lightly touch the sediment when these insects skim onto wet ground at shorelines. Dimensions of the thorax of the trace indicate relatively weak flight ability compared to fossils from the Early Permian, making doubtful the hypothesis that the trace maker was flight capable. Ultimately, this fossil best fits a scenario in which a neopteran insect skimmed across the surface of water, then folded its wings. Surface skimming as a precursor to the evolution of flight in insects is supported by this fossil evidence of skimming behavior in a Carboniferous insect. PMID:23289577

  4. Experimental evidence concerning the different behavior of energy and exergy performance indicators of refrigeration systems in transient regimes

    NASA Astrophysics Data System (ADS)

    Vasilescu, Elena Eugenia; Feidt, Michel; Boussehain, Rahal; Dobrovicescu, Alexandru

    2016-01-01

    This article presents the results obtained from an energy-exergy analysis of a vapor compression refrigeration system during induced transient regimes. Using experimental data, exergy destruction as a function of time under the influence of some factors that perturb the stationary regime, such as deactivation of piston, variation of mass flow rate and initial temperature of cooled fluid, and diminution of the compressor rotation speed, was calculated. Under the perturbation, an antagonistic increase in the coefficient of performance and a decrease in exergy efficiency were noted.

  5. Eosinophilic esophagitis: published evidences for disease subtypes, indications for patient subpopulations, and how to translate patient observations to murine experimental models.

    PubMed

    Mudde, Anne C A; Lexmond, Willem S; Blumberg, Richard S; Nurko, Samuel; Fiebiger, Edda

    2016-01-01

    Eosinophilic esophagitis (EoE) is a chronic inflammatory disorder of the esophagus and commonly classified as a Th2-type allergy. Major advances in our understanding of the EoE pathophysiology have recently been made, but clinicians struggle with highly unpredictable therapy responses indicative of phenotypic diversity within the patient population. Here, we summarize evidences for the existence of EoE subpopulations based on diverse inflammatory characteristics of the esophageal tissue in EoE. Additionally, clinical characteristics of EoE patients support the concept of disease subtypes. We conclude that clinical and experimental evidences indicate that EoE is an umbrella term for conditions that are unified by esophageal eosinophilia but that several disease subgroups with various inflammatory esophageal patterns and/or different clinical features exist. We further discuss strategies to study the pathophysiologic differences as observed in EoE patients in murine experimental EoE. Going forward, models of EoE that faithfully mimic EoE subentities as defined in humans will be essential because mechanistic studies on triggers which regulate the onset of diverse EoE subpopulations are not feasible in patients. Understanding how and why different EoE phenotypes develop will be a first and fundamental step to establish strategies that integrate individual variations of the EoE pathology into personalized therapy. PMID:27458501

  6. 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…

  7. Comment on Marden (2013): "reanalysis and experimental evidence indicate that the earliest trace fossil of a winged insect was a surface skimming neopteran".

    PubMed

    Benner, Jacob S; Knecht, Richard J; Engel, Michael S

    2013-07-01

    Marden's (2013) reanalysis of Knecht et al. (2011) suggesting that specimen SEMC-F97 is the result of the skimming behavior of a neopteran insect and, more importantly, fossil evidence of "… surface skimming as a precursor to the evolution of flight in insects" (Marden 2013) is found to be deficient on three fronts: (1) the principal specimen was never viewed firsthand which led to significant morphological misinterpretations; (2) poorly designed and executed neoichnological experiments led to incredulous results; and (3) the assumption that this specimen is fossil evidence supporting the surface skimming hypothesis of the origin of insect flight despite the fact that since its induction into the literature that hypothesis has been refuted based on significant paleontological, phylogenetic, genetic, and developmental evidence. PMID:23815667

  8. Experimental evidence for subshell closure in {sup 8}He and indication of a resonant state in {sup 7}He below 1 MeV

    SciTech Connect

    Skaza, F.; Lapoux, V.; Keeley, N.; Alamanos, N.; Pollacco, E. C.; Auger, F.; Drouart, A.; Gillibert, A.; Nalpas, L.; Obertelli, A.; Raabe, R.; Sida, J.-L.; Giot, L.; Roussel-Chomaz, P.; Kemper, K. W.

    2006-04-15

    The spectroscopy of the unstable {sup 8}He and unbound {sup 7}He nuclei is investigated via the p({sup 8}He, d) transfer reaction with a 15.7A MeV {sup 8}He beam from the SPIRAL facility. The emitted deuterons were detected by the telescope array MUST. The results are analyzed within the coupled-channels Born approximation framework, and a spectroscopic factor C{sup 2}S=4.4{+-}1.3 for neutron pickup to the {sup 7}He{sub g.s.} is deduced. This value is consistent with a full p3/2 subshell for {sup 8}He. Tentative evidence for the first excited state of {sup 7}He is found at E{sup *}=0.9{+-}0.5 MeV (width {gamma}=1.0{+-}0.9 MeV). The second one is observed at a position compatible with previous measurements, E{sup *}=2.9{+-}0.1 MeV. Both are in agreement with previous separate measurements. The reproduction of the first excited state below 1 MeV would be a challenge for the most sophisticated nuclear theories.

  9. Sexually antagonistic genes: experimental evidence.

    PubMed

    Rice, W R

    1992-06-01

    When selection differs between the sexes, a mutation beneficial to one sex may be harmful to the other (sexually antagonistic). Because the sexes share a common gene pool, selection in one sex can interfere with the other's adaptive evolution. Theory predicts that sexually antagonistic mutations should accumulate in tight linkage with a new sex-determining gene, even when the harm to benefit ratio is high. Genetic markers and artificial selection were used to make a pair of autosomal genes segregate like a new pair of sex-determining genes in a Drosophila melanogaster model system. A 29-generation study provides experimental evidence that sexually antagonistic genes may be common in nature and will accumulate in response to a new sex-determining gene. PMID:1604317

  10. Suicide and antidepressants: what current evidence indicates.

    PubMed

    Nischal, Anil; Tripathi, Adarsh; Nischal, Anuradha; Trivedi, J K

    2012-01-01

    The documented efficacy and long-term benefit of antidepressants in patients with recurrent forms of severe anxiety or depressive disorders support their use in those individuals with these disorders, who experience suicidal thoughts or behavior. In general, it is assumed that antidepressants are beneficial for all symptoms of depression, including suicidality. However, some evidence suggests that Selective Serotonin Reuptake Inhibitors [SSRIs] may cause worsening of suicidal ideas in vulnerable patients. Systematic reviews and pooled analysis of experimental, observational, and epidemiological studies have investigated the use of SSRIs and their association with suicidality. Taking account of the methodological limitations of these studies, the current evidence fails to provide a clear relationship between their use and risk of suicidality in adults. However, in children and adolescents, there appears to be a bit of increased risk of suicidal ideations and attempts, but not of completed suicides. This risk can be anticipated and managed clinically. Clinicians are, therefore, advised to maintain a close follow-up during the initial treatment periods and remain vigilant of this risk. This advisory, however, should not deter clinicians from the use of effective dosages of antidepressants for a sufficient period of time, in every age group of patients, when clinically needed, and if found suitable otherwise. PMID:22654381

  11. Suicide and Antidepressants: What Current Evidence Indicates

    PubMed Central

    Nischal, Anil; Tripathi, Adarsh; Nischal, Anuradha; Trivedi, J. K.

    2012-01-01

    The documented efficacy and long-term benefit of antidepressants in patients with recurrent forms of severe anxiety or depressive disorders support their use in those individuals with these disorders, who experience suicidal thoughts or behavior. In general, it is assumed that antidepressants are beneficial for all symptoms of depression, including suicidality. However, some evidence suggests that Selective Serotonin Reuptake Inhibitors [SSRIs] may cause worsening of suicidal ideas in vulnerable patients. Systematic reviews and pooled analysis of experimental, observational, and epidemiological studies have investigated the use of SSRIs and their association with suicidality. Taking account of the methodological limitations of these studies, the current evidence fails to provide a clear relationship between their use and risk of suicidality in adults. However, in children and adolescents, there appears to be a bit of increased risk of suicidal ideations and attempts, but not of completed suicides. This risk can be anticipated and managed clinically. Clinicians are, therefore, advised to maintain a close follow-up during the initial treatment periods and remain vigilant of this risk. This advisory, however, should not deter clinicians from the use of effective dosages of antidepressants for a sufficient period of time, in every age group of patients, when clinically needed, and if found suitable otherwise. PMID:22654381

  12. Epidemiological evidence indicates asbestos causes laryngeal cancer

    SciTech Connect

    Smith, A.H.; Handley, M.A.; Wood, R. )

    1990-06-01

    A variety of opinions have been expressed in the literature concerning asbestos and laryngeal cancer. This paper presents an analysis of epidemiological studies based on criteria that prioritized the most heavily exposed cohorts. Emphasis was given to the six cohorts or subcohorts with lung cancer relative risk estimates of 2 or more. The two groups of workers with the highest lung cancer relative risk estimates (4.06 and 3.28) both gave strong support for a causal association of asbestos and laryngeal cancer, with relative risk estimates of 1.91 (90% confidence limits 1.00 to 3.34) and 3.75 (90% confidence limits 1.01 to 9.68), respectively. Confounding with cigarette smoking or alcohol consumption does not explain the findings. Case-control studies gave mixed results, but generally supported the hypothesis. It was concluded that asbestos is a probable cause of laryngeal cancer in view of the reasonable consistency of the studies, the strength of the association in key studies, the evidence for dose-response relationships, and the biological plausibility for asbestos being a cause of laryngeal cancer. 48 references.

  13. Experimental evidence of quantum randomness incomputability

    SciTech Connect

    Calude, Cristian S.; Dinneen, Michael J.; Dumitrescu, Monica; Svozil, Karl

    2010-08-15

    In contrast with software-generated randomness (called pseudo-randomness), quantum randomness can be proven incomputable; that is, it is not exactly reproducible by any algorithm. We provide experimental evidence of incomputability--an asymptotic property--of quantum randomness by performing finite tests of randomness inspired by algorithmic information theory.

  14. Experimental evidence for Abraham pressure of light

    NASA Astrophysics Data System (ADS)

    Zhang, Li; She, Weilong; Peng, Nan; Leonhardt, Ulf

    2015-05-01

    The question of how much momentum light carries in media has been debated for over a century. Two rivalling theories, one from 1908 by Hermann Minkowski and the other from 1909 by Max Abraham, predict the exact opposite when light enters an optical material: a pulling force in Minkowski's case and a pushing force in Abraham's. Most experimental tests have agreed with Minkowski's theory, but here we report the first quantitative experimental evidence for Abraham's pushing pressure of light. Our results matter in optofluidics and optomechanics, and wherever light exerts mechanical pressure.

  15. The support of human genetic evidence for approved drug indications.

    PubMed

    Nelson, Matthew R; Tipney, Hannah; Painter, Jeffery L; Shen, Judong; Nicoletti, Paola; Shen, Yufeng; Floratos, Aris; Sham, Pak Chung; Li, Mulin Jun; Wang, Junwen; Cardon, Lon R; Whittaker, John C; Sanseau, Philippe

    2015-08-01

    Over a quarter of drugs that enter clinical development fail because they are ineffective. Growing insight into genes that influence human disease may affect how drug targets and indications are selected. However, there is little guidance about how much weight should be given to genetic evidence in making these key decisions. To answer this question, we investigated how well the current archive of genetic evidence predicts drug mechanisms. We found that, among well-studied indications, the proportion of drug mechanisms with direct genetic support increases significantly across the drug development pipeline, from 2.0% at the preclinical stage to 8.2% among mechanisms for approved drugs, and varies dramatically among disease areas. We estimate that selecting genetically supported targets could double the success rate in clinical development. Therefore, using the growing wealth of human genetic data to select the best targets and indications should have a measurable impact on the successful development of new drugs. PMID:26121088

  16. 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

  17. 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.

  18. Evidence for gammacerane as an indicator of water column stratification

    NASA Technical Reports Server (NTRS)

    Sinninghe Damste, J. S.; Kenig, F.; Koopmans, M. P.; Koster, J.; Schouten, S.; Hayes, J. M.; de Leeuw, J. W.

    1995-01-01

    A new route for the formation of gammacerane from tetrahymanol is proposed; in addition to dehydration and hydrogenation, sulphurisation and early C-S cleavage are shown to be important in the pathway of formation, especially in marine sediments. Evidence is twofold. First, relatively large amounts of the gammacerane skeleton are sequestered in S-rich macromolecular aggregates formed by natural sulphurisation of functionalised lipids. Selective cleavage of polysulphide linkages with MeLi/MeI led to formation of 3-methylthiogammacerane, indicating that the gammacerane skeleton is primarily bound via sulphur at position 3, consistent with the idea that tetrahymanol (or the corresponding ketone) is the precursor for gammacerane. Second, upon mild artificial maturation of two sediments using hydrous pyrolysis, gammacerane is released from S-rich macromolecular aggregates by cleavage of the relatively weak C-S bonds. The stable carbon isotopic compositions of gammacerane and lipids derived from primary producers and green sulphur bacteria in both the Miocene Gessoso-solfifera and Upper Jurassic Allgau Formations indicate that gammacerane is derived from bacterivorous ciliates which were partially feeding on green sulphur bacteria. This demonstrates that anaerobic ciliates living at or below the chemocline are important sources for gammacerane, consistent with the fact that ciliates only biosynthesize tetrahymanol if their diet is deprived of sterols. This leads to the conclusion that gammacerane is an indicator for water column stratification, which solves two current enigmas in gammacerane geochemistry. Firstly, it explains why gammacerane is often found in sediments deposited under hypersaline conditions but is not necessarily restricted to this type of deposits. Secondly, it explains why lacustrine deposits may contain abundant gammacerane since most lakes in the temperate climatic zones are stratified during summer.

  19. Experimental Evidence of Chaos from Memristors

    NASA Astrophysics Data System (ADS)

    Gambuzza, Lucia Valentina; Fortuna, Luigi; Frasca, Mattia; Gale, Ella

    Until now, most memristor-based chaotic circuits proposed in the literature are based on mathematical models which assume ideal characteristics such as piecewise-linear or cubic nonlinearities. The idea, illustrated here and originating from the experimental approach for device characterization, is to realize a chaotic system exploiting the nonlinearity of only one memristor with a very simple experimental set-up using feedback. In this way, a simple circuit is obtained and chaos is experimentally observed and is confirmed by the calculation of the largest Lyapunov exponent. Numerical results using the Strukov model support the existence of robust chaos in our circuit. To our knowledge, this is the first experimental demonstration of chaos in a real memristor circuit and suggests that memristors are well placed for hardware encryption.

  20. Natural compounds as anticancer agents: Experimental evidence

    PubMed Central

    Wang, Jiao; Jiang, Yang-Fu

    2012-01-01

    Cancer prevention research has drawn much attention worldwide. It is believed that some types of cancer can be prevented by following a healthy life style. Cancer chemoprevention by either natural or synthetic agents is a promising route towards lowering cancer incidence. In recent years, the concept of cancer chemoprevention has evolved greatly. Experimental studies in animal models demonstrate that the reversal or suppression of premalignant lesions by chemopreventive agents is achievable. Natural occurring agents such as dietary phytochemicals, tea polyphenols and resveratrol show chemopreventive activity in animal models. Moreover, clinical trials for testing the safety and efficacy of a variety of natural agents in preventing or treating human malignancy have been ongoing. Here, we summarize experimental data on the chemopreventive or tumor suppressive effects of several natural compounds including curcumin, (-)-epigallocatechin-3-gallate, resveratrol, indole-3-carbinol, and vitamin D. PMID:24520533

  1. Experimental Evidence for a Wave Cosmology

    NASA Astrophysics Data System (ADS)

    Wagner, Orvin

    1997-04-01

    I have previously reported (see Wagner Web Site) slow moving, charge and matter separating, longitudinal waves, threading through matter and space. The waves I report are apparently produced by oscillating sources such as the sun and the planets, electromagnetic sources, and experimentally using electromagnetic sources. Experimentally the excited wavelengths are found to be close to the dimensions of the electromagnetic source regardless of its frequency. Oscillations of these waves can explain the solar cycle and determine planet and other satellite locations: r=r0exp(0.625N) where N is an integer for a particular planet or satellite of a planet and r0 is the radius of the sun or planet when the satellites were placed. This equation describes waves that are speeding up as the density of the medium (dark matter?) decreases moving away from the source. These waves are found experimentally to produce standing waves around any source apparently due to special reflection from the medium. These observations are consistent with the idea that these waves produce a pattern around a star with matter tending to collect only at specific locations(N) to produce satellites.

  2. Dichlorvos carcinogenicity: an assessment of the weight of experimental evidence.

    PubMed

    Mennear, J H

    1994-12-01

    After 30 years of experience with human exposure to dichlorvos (DDVP) in the home, workplace, and sickroom, the U.S. EPA has published its intent to revoke the food additive registration of this cholinesterase-inhibiting insecticide. The basis for the Agency action is the result of the National Toxicology Program (NTP) toxicology and carcinogenesis study of DDVP in rats and mice (NTP Technical Report No. 342, September 1989). In those experiments the NTP considered the result in the female mouse portion of the study to afford unequivocal evidence of carcinogenicity. The NTP considered the interpretations of the male and female rat and the male mouse studies to be less than clear. Despite the NTP interpretation, the EPA considers the male rat data (increased incidence of mononuclear cell leukemia) to be sufficient to warrant the regulatory change. The purpose of this report is to summarize a review of the interpretation of the NTP data and to assess the predictive validity of the results relative to potential human health impact. Critical review of experimental data indicates that the evidence for a carcinogenic effect of DDVP in animals is equivocal. Further, DDVP possess no in vivo mutagenic activity in mammalian assay systems and it bears no significant structural similarity to known carcinogens. Therefore, a weight-of-the-evidence analysis leads to the conclusion that DDVP poses neither mutagenic nor carcinogenic risks to humans exposed under normal conditions of use of foreseeable conditions of misuse. PMID:7724838

  3. Reconciling Experimental and Quasi-Experimental Evidence on the Impact of Full-Day Kindergarten

    ERIC Educational Resources Information Center

    Gibbs, Chloe

    2013-01-01

    This paper addresses the question of how to interpret evidence on the impact of full-day kindergarten resulting from different study designs, and provides guidance on how this evidence taken in tandem may inform the design and implementation of full-day kindergarten policies. Incorporating both experimental and quasi-experimental estimates on…

  4. Experimental evidence of condensation-driven airflow

    NASA Astrophysics Data System (ADS)

    Bunyard, P.; Hodnett, M.; Poveda, G.; Burgos Salcedo, J. D.; Peña, C.

    2015-10-01

    The dominant "convection" model of atmospheric circulation is based on the premise that hot air expands and rises, to be replaced by colder air, thereby creating horizontal surface winds. A recent theory put forward by Makarieva and Gorshkov (2007, 2013) maintains that the primary motive force of atmospheric circulation derives from the intense condensation and sharp pressure reduction that is associated with regions where a high rate of evapotranspiration from natural closed-canopy forests provides the "fuel" for cloud formation. The net result of the "biotic pump" theory is that moist air flows from ocean to land, drawn in by the pressure changes associated with a high rate of condensation. To test the physics underpinning the biotic pump theory, namely that condensation of water vapour, at a sufficiently high rate, results in an uni-directional airflow, a 5 m tall experimental apparatus was designed and built, in which a 20 m3 body of atmospheric air is enclosed inside an annular 14 m long space (a "square donut") around which it can circulate freely, allowing for rotary air flows. One vertical side of the apparatus contains some 17 m of copper refrigeration coils, which cause condensation. The apparatus contains a series of sensors measuring temperature, humidity and barometric pressure every five seconds, and air flow every second. The laws of Newtonian physics are used in calculating the rate of condensation inside the apparatus. The results of more than one hundred experiments show a highly significant correlation, with r2 > 0.9, of airflow and the rate of condensation. The rotary air flows created appear to be consistent both in direction and velocity with the biotic pump hypothesis, the critical factor being the rate change in the partial pressure of water vapour in the enclosed body of atmospheric air. Air density changes, in terms of kinetic energy, are found to be orders of magnitude smaller than the kinetic energy of partial pressure change. The

  5. Female Rose Bitterling Prefer MHC-Dissimilar Males: Experimental Evidence

    PubMed Central

    Reichard, Martin; Spence, Rowena; Bryjová, Anna; Bryja, Josef; Smith, Carl

    2012-01-01

    The role of genetic benefits in female mate choice remains a controversial aspect of sexual selection theory. In contrast to “good allele” models of sexual selection, “compatible allele” models of mate choice predict that females prefer mates with alleles complementary to their own rather than conferring additive effects. While correlative results suggest complementary genetic effects to be plausible, direct experimental evidence is scarce. A previous study on the Chinese rose bitterling (Rhodeus ocellatus) demonstrated a positive correlation between female mate choice, offspring growth and survival, and the functional dissimilarity between the Major Histocompatibility Complex (MHC) alleles of males and females. Here we directly tested whether females used cues associated with MHC genes to select genetically compatible males in an experimental framework. By sequentially pairing females with MHC similar and dissimilar males, based on a priori known MHC profiles, we showed that females discriminated between similar and dissimilar males and deposited significantly more eggs with MHC dissimilar males. Notably, the degree of dissimilarity was an important factor for female decision to mate, possibly indicating a potential threshold value of dissimilarity for decision making, or of an indirect effect of the MHC. PMID:22815816

  6. Experimental evidence for lattice effects in high temperature superconductors

    SciTech Connect

    Billinge, S.J.L.; Kwei, G.H.; Thompson, J.D.

    1994-01-18

    We present an overview of the experimental evidence for a role of the lattice in the mechanism of high temperature superconductivity. It appears unlikely that a solely conventional electron-phonon interaction produces the pairing. However, there is ample evidence of strong electron and spin to lattice coupling and observations of a response of the lattice to the electronic state. We draw attention to the importance of the local structure in discussions of lattice effects in high-{Tc} superconductivity.

  7. Evidence of an infrared luminosity indicator for galaxies

    NASA Technical Reports Server (NTRS)

    Feigelson, Eric D.; Isobe, Takashi; Weedman, Daniel W.

    1987-01-01

    To elucidate the nature of infrared-luminous galaxies discovered with the IRAS satellite, the optical and infrared luminosities of 1161 Markarian galaxies and 2146 'normal' galaxies from the CfA redshift survey are compared. Survival analysis statistical methods that take upper limits fully into account are used. It is found that L(IR)/L(B) is statistically correlated with L(60) in both samples, though they differ in the distribution at low luminosities. The derived correlation shows that L(IR)/L(B) provides an indicator for L(60). Since galaxies selected in unbiased IRAS surveys will have higher L(IR)/L(B) than optically selected galaxies, they are therefore also selected for high L(60).

  8. 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

  9. Rotational grazing on rangelands: Reconciliation of perception and experimental evidence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In spite of overwhelming experimental evidence to the contrary, rotational grazing continues to be promoted and implemented as the only viable grazing strategy. The goals of this synthesis are to 1) reevaluate the complexity, underlying assumptions, and ecological processes of grazed ecosystems, 2) ...

  10. 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…

  11. Experimental evidence of contagious yawning in budgerigars (Melopsittacus undulatus).

    PubMed

    Gallup, Andrew C; Swartwood, Lexington; Militello, Janine; Sackett, Serena

    2015-09-01

    Experimental evidence of contagious yawning has only been documented in four mammalian species. Here, we report the results from two separate experimental studies designed to investigate the presence of contagious yawning in a social parrot, the budgerigar (Melopsittacus undulatus). In Study 1, birds were paired in adjacent cages with and without visual barriers, and the temporal association of yawning was assessed between visual conditions. In Study 2, the same birds were exposed to video stimuli of both conspecific yawns and control behavior, and yawning frequency was compared between conditions. Results from both studies demonstrate that yawning is contagious. To date, this is the first experimental evidence of contagious yawning in a non-mammalian species. We propose that future research could use budgerigars to explore questions related to basic forms of empathic processing. PMID:26012708

  12. Experimental evidence of replica symmetry breaking in random lasers

    NASA Astrophysics Data System (ADS)

    Ghofraniha, N.; Viola, I.; di Maria, F.; Barbarella, G.; Gigli, G.; Leuzzi, L.; Conti, C.

    2015-01-01

    Spin-glass theory is one of the leading paradigms of complex physics and describes condensed matter, neural networks and biological systems, ultracold atoms, random photonics and many other research fields. According to this theory, identical systems under identical conditions may reach different states. This effect is known as replica symmetry breaking and is revealed by the shape of the probability distribution function of an order parameter named the Parisi overlap. However, a direct experimental evidence in any field of research is still missing. Here we investigate pulse-to-pulse fluctuations in random lasers, we introduce and measure the analogue of the Parisi overlap in independent experimental realizations of the same disordered sample, and we find that the distribution function yields evidence of a transition to a glassy light phase compatible with a replica symmetry breaking.

  13. Experimental evidence of hyperbolic heat conduction in processed meat

    SciTech Connect

    Mitra, K.; Kumar, S.; Vedavarz, A.; Moallemi, M.K.

    1995-08-01

    The objective of this paper is to present experimental evidence of the wave nature of heat propagation in processed meat and to demonstrate that the hyperbolic heat conduction model is an accurate representation, on a macroscopic level, of the heat conduction process in such biological material. The value of the characteristic thermal time of a specific material, processed bologna meat, is determined experimentally. As a part of the work different thermophysical properties are also measured. The measured temperature distributions in the samples are compared with the Fourier results and significant deviation between the two is observed, especially during the initial stages of the transient conduction process. The measured values are found to match the theoretical non-Fourier hyperbolic predictions very well. The superposition of waves occurring inside the meat sample due to the hyperbolic nature of heat conduction is also proved experimentally. 14 refs., 7 figs., 2 tabs.

  14. Chemicals and cancer in humans: first evidence in experimental animals.

    PubMed Central

    Huff, J

    1993-01-01

    Certain human diseases have been traced to exposure to environmental and occupational chemicals. In many instances the first evidence of potential adverse effects came from experimental studies and were subsequently discovered in humans. Associations of human cancers, as a diverse group of diseases, and chemicals have been made since the middle 1700s. Since then, nearly 100 chemicals, mixtures of chemicals, or exposure circumstances are now recognized as being or strongly implicated as being carcinogenic to humans. Of the less than 1000 agents evaluated adequately for carcinogenicity in laboratory animals, a varying spectrum of data from studies on humans are available for only about 20-25%. So far, more than 60 agents are linked unequivocally as causing cancer in humans, and another 50 or so are strongly suspected of being carcinogenic to humans. Not all of these have been or can be evaluated in animals because some are industrial processes or "occupations," some are environmental and cultural risk factors, and some are mixtures of agents. For those that can be studied experimentally, the qualitative concordance between humans and animals approaches unity, and in every case there is at least one common organ site of cancer in both species. The evidence of carcinogenicity in experimental animals preceded that observed in humans for nearly 30 agents and is the subject of this paper. PMID:8354167

  15. The tripole vortex: Experimental evidence and explicit solutions.

    PubMed

    Kizner, Ziv; Khvoles, Ruvim

    2004-01-01

    Based on experimental evidence, explicit vorticity-distributed solutions to the Euler equations in two dimensions are constructed describing the tripole vortex. The vortex form and the solution outside the region of nonzero vorticity are derived analytically, while the interior is solved numerically. The continuous-vorticity solution reproduces the main features of the tripoles observed in laboratory experiments and numerical simulations-their shape, flow pattern, and the form of the nonlinear vorticity vs streamfunction relation. The approach followed in the construction of a tripole proves to be beneficial in the search for higher-order multipoles, an example being a smooth quadrupole solution. PMID:15324169

  16. Sleep Duration and Cardiovascular Disease Risk: Epidemiologic and Experimental Evidence.

    PubMed

    Covassin, Naima; Singh, Prachi

    2016-03-01

    Inadequate sleep is increasingly pervasive, and the impact on health remains to be fully understood. The cardiovascular consequences alone appear to be substantial. This review summarizes epidemiologic evidence regarding the association between extremes of sleep duration and the prevalence and incidence of cardiovascular diseases. The adverse effects of experimental sleep loss on physiological functions are discussed, along with cardiovascular risk factors that may underlie the association with increased morbidity and mortality. Current data support the concept that inadequate sleep duration confers heightened cardiovascular risk. Thus implementation of preventative strategies may reduce the potential disease burden associated with this high-risk behavior. PMID:26972035

  17. Experimental Evidence for Dark Excitons in Monolayer WSe_{2}.

    PubMed

    Zhang, Xiao-Xiao; You, Yumeng; Zhao, Shu Yang Frank; Heinz, Tony F

    2015-12-18

    Transition metal dichalcogenides in the class MX_{2} (M=Mo, W; X=S, Se) have been identified as direct-gap semiconductors in the monolayer limit. Here, we examine light emission of monolayer WSe_{2} using temperature-dependent photoluminescence and time-resolved photoluminescence spectroscopy. We present experimental evidence for the existence of an optically forbidden dark state of the band-gap exciton that lies tens of meV below the optically bright state. The presence of the dark state is manifest in the strong quenching of light emission observed at reduced temperatures. The experimental findings are consistent with theoretical predictions of spin-polarized conduction and valence bands at the K point of the Brillouin zone, with the minimum gap occurring between bands of opposite electron spin. PMID:26722944

  18. An Evaluation of Multiple Single-Case Outcome Indicators Using Convergent Evidence Scaling

    ERIC Educational Resources Information Center

    McGill, Ryan J.; Busse, R. T.

    2014-01-01

    The purpose of this article is to evaluate the consistency of five single-case outcome indicators, used to assess response-to-intervention data from a pilot Tier 2 reading intervention that was implemented at an elementary school. Using convergent evidence scaling, the indicators were converted onto a common interpretive scale for each case…

  19. Experimental evidence for compositional syntax in bird calls.

    PubMed

    Suzuki, Toshitaka N; Wheatcroft, David; Griesser, Michael

    2016-01-01

    Human language can express limitless meanings from a finite set of words based on combinatorial rules (i.e., compositional syntax). Although animal vocalizations may be comprised of different basic elements (notes), it remains unknown whether compositional syntax has also evolved in animals. Here we report the first experimental evidence for compositional syntax in a wild animal species, the Japanese great tit (Parus minor). Tits have over ten different notes in their vocal repertoire and use them either solely or in combination with other notes. Experiments reveal that receivers extract different meanings from 'ABC' (scan for danger) and 'D' notes (approach the caller), and a compound meaning from 'ABC-D' combinations. However, receivers rarely scan and approach when note ordering is artificially reversed ('D-ABC'). Thus, compositional syntax is not unique to human language but may have evolved independently in animals as one of the basic mechanisms of information transmission. PMID:26954097

  20. Experimental evidence for compositional syntax in bird calls

    PubMed Central

    Suzuki, Toshitaka N.; Wheatcroft, David; Griesser, Michael

    2016-01-01

    Human language can express limitless meanings from a finite set of words based on combinatorial rules (i.e., compositional syntax). Although animal vocalizations may be comprised of different basic elements (notes), it remains unknown whether compositional syntax has also evolved in animals. Here we report the first experimental evidence for compositional syntax in a wild animal species, the Japanese great tit (Parus minor). Tits have over ten different notes in their vocal repertoire and use them either solely or in combination with other notes. Experiments reveal that receivers extract different meanings from ‘ABC' (scan for danger) and ‘D' notes (approach the caller), and a compound meaning from ‘ABC–D' combinations. However, receivers rarely scan and approach when note ordering is artificially reversed (‘D–ABC'). Thus, compositional syntax is not unique to human language but may have evolved independently in animals as one of the basic mechanisms of information transmission. PMID:26954097

  1. Experimental evidence of the double-porosity effects in geomaterials

    NASA Astrophysics Data System (ADS)

    Tran Ngoc, Tien; Lewandowska, Jolanta; Bertin, Henri

    2014-06-01

    Double-porosity is an important characteristic of microstructure in a large range of geomaterials. It designs porous media with connected fissures/fractures or aggregated soils. The origin of double-porosity can be natural or/and it can result from mechanical, chemical or biological damage. The presence of double-porosity can significantly affect the behaviour of geomaterials. In this paper we provide an experimental evidence of the double-porosity effects by performing laboratory experiments. Series of tracer dispersion experiments (in saturated and unsaturated steady-state water flow conditions) in a physical model of double-porosity geomaterial were carried out. For the comparative purposes, experiments of the same type were also performed in a singleporosity model medium. The results clearly showed that the double-porosity microstructure leads to the non-Fickian behaviour of the tracer (early breakthrough and long tail) in both saturated and unsaturated cases.

  2. Experimental evidence for deterministic chaos in thermal pulse combustion

    SciTech Connect

    Daw, C.S.; Thomas, J.F.; Richards, G.A.; Narayanaswami, L.L.

    1994-12-31

    Given the existence of chaotic oscillations in reacting chemical systems, it is reasonable to ask whether or not similar phenomena can occur in combustion. In this paper, the authors present experimental evidence that kinetically driven chaos occurs in a highly simplified thermal pulse combustor. The combustor is a well-stirred reactor with a tailpipe extending from one end. Fuel and air are injected into the combustion chamber through orifices in the end opposite the tailpipe. Propane with the fuel used in all cases. From the experimental data analyses, it is clear that deterministic chaos is an important factor in thermal pulse combustor dynamics. While the authors have only observed such behavior in this particular type combustor to date, they infer from their understanding of the origins of the chaos that it is likely to exist in other pulse combustors and even nonpulsing combustion. They speculate that realization of the importance of chaos in affecting flame stability could lead to significant changes in combustor design and control.

  3. 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. PMID:22875725

  4. Experimental evidence that sperm maturation drives protandry in an ectotherm.

    PubMed

    Breedveld, Merel C; Fitze, Patrick S

    2016-09-01

    Protandry, i.e., the earlier arrival to breeding areas of males than females, has attracted a lot of scientific attention. However, evidence for the evolutionary hypotheses of protandry is surprisingly scarce. Here, we experimentally manipulate the time of emergence from hibernation of males, relative to females, in the common lizard, Zootoca vivipara. We test whether the timing of emergence affects sperm maturation and mating success, to disentangle among proposed selective advantages of protandry. Our results experimentally demonstrate that the timing of emergence affects the date of sperm presence. Moreover, the degree of protandry affected whether males had sperm upon their first encounter with females, but it did not affect the probability of copulating. Mating occurred independent of male fertility and mating during infertility was least common in early emerging males. Early emergence from hibernation by males, relative to females, thus increases the male's chance of fertilising eggs and later emergence from hibernation by females reduces the female's probability of mating with infertile males. These results point to direct reproductive benefits of protandry in males and females, where earlier emergence is predicted to increase the male's opportunities to inseminate mates, and later emergence reduces the female's probability of copulating with infertile males. This suggests that protandry evolved due to the time required for sperm maturation after emergence from hibernation. PMID:27259749

  5. Experimental Evidence for Phonemic Contrasts in a Nonhuman Vocal System

    PubMed Central

    Savage, James L.; Russell, Andrew F.; Townsend, Simon W.

    2015-01-01

    The ability to generate new meaning by rearranging combinations of meaningless sounds is a fundamental component of language. Although animal vocalizations often comprise combinations of meaningless acoustic elements, evidence that rearranging such combinations generates functionally distinct meaning is lacking. Here, we provide evidence for this basic ability in calls of the chestnut-crowned babbler (Pomatostomus ruficeps), a highly cooperative bird of the Australian arid zone. Using acoustic analyses, natural observations, and a series of controlled playback experiments, we demonstrate that this species uses the same acoustic elements (A and B) in different arrangements (AB or BAB) to create two functionally distinct vocalizations. Specifically, the addition or omission of a contextually meaningless acoustic element at a single position generates a phoneme-like contrast that is sufficient to distinguish the meaning between the two calls. Our results indicate that the capacity to rearrange meaningless sounds in order to create new signals occurs outside of humans. We suggest that phonemic contrasts represent a rudimentary form of phoneme structure and a potential early step towards the generative phonemic system of human language. PMID:26121619

  6. Experimental Evidence for Phonemic Contrasts in a Nonhuman Vocal System.

    PubMed

    Engesser, Sabrina; Crane, Jodie M S; Savage, James L; Russell, Andrew F; Townsend, Simon W

    2015-06-01

    The ability to generate new meaning by rearranging combinations of meaningless sounds is a fundamental component of language. Although animal vocalizations often comprise combinations of meaningless acoustic elements, evidence that rearranging such combinations generates functionally distinct meaning is lacking. Here, we provide evidence for this basic ability in calls of the chestnut-crowned babbler (Pomatostomus ruficeps), a highly cooperative bird of the Australian arid zone. Using acoustic analyses, natural observations, and a series of controlled playback experiments, we demonstrate that this species uses the same acoustic elements (A and B) in different arrangements (AB or BAB) to create two functionally distinct vocalizations. Specifically, the addition or omission of a contextually meaningless acoustic element at a single position generates a phoneme-like contrast that is sufficient to distinguish the meaning between the two calls. Our results indicate that the capacity to rearrange meaningless sounds in order to create new signals occurs outside of humans. We suggest that phonemic contrasts represent a rudimentary form of phoneme structure and a potential early step towards the generative phonemic system of human language. PMID:26121619

  7. Measuring psychological resilience to disasters: are evidence-based indicators an achievable goal?

    PubMed Central

    2013-01-01

    Despite rising interest on the concept of societal resilience and its measurement, little has been done to provide operational indicators. Importantly, an evidence-based approach to assess the suitability of indicators remains unexplored. Furthermore few approaches that exist do not investigate indicators of psychological resilience, which is emerging as an important component of societal resilience to disasters. Disasters are events which overwhelm local capacities, often producing human losses, injury and damage to the affected communities. As climate hazards and disasters are likely to increase in the coming decades, strengthening the capacity of societies to withstand these shocks and recover quickly is vital. In this review, we search the Web of Knowledge to summarize the evidence on indicators of psychological resilience to disasters and provided a qualitative assessment of six selected studies. We find that an evidence-based approach using features from systematic reviews is useful to compile, select and assess the evidence and elucidate robust indicators. We conclude that strong social support received after a disaster is associated with an increased psychological resilience whereas a female gender is connected with a decrease in the likelihood of a resilient outcome. These results are consistent across disaster settings and cultures and are representative of approximately 13 million disaster-exposed civilians of adult age. An approach such as this that collects and evaluates evidence will allow indicators of resilience to be much more revealing and useful in the future. They will provide a robust basis to prioritize indicators to act upon through intersectoral policies and post-disaster public health interventions. PMID:24359448

  8. 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. PMID:26381440

  9. Semantics guide infants' vowel learning: Computational and experimental evidence.

    PubMed

    Ter Schure, S M M; Junge, C M M; Boersma, P P G

    2016-05-01

    In their first year, infants' perceptual abilities zoom in on only those speech sound contrasts that are relevant for their language. Infants' lexicons do not yet contain sufficient minimal pairs to explain this phonetic categorization process. Therefore, researchers suggested a bottom-up learning mechanism: infants create categories aligned with the frequency distributions of sounds in their input. Recent evidence shows that this bottom-up mechanism may be complemented by the semantic context in which speech sounds occur, such as simultaneously present objects. To test this hypothesis, we investigated whether discrimination of a non-native vowel contrast improves when sounds from the contrast were paired consistently or randomly with two distinct visually presented objects, while the distribution of speech tokens suggested a single broad category. This was assessed in two ways: computationally, namely in a neural network simulation, and experimentally, namely in a group of 8-month-old infants. The neural network, trained with a large set of sound-meaning pairs, revealed that two categories emerge only if sounds are consistently paired with objects. A group of 49 real 8-month-old infants did not immediately show sensitivity to the pairing condition; a later test at 18 months with some of the same infants, however, showed that this sensitivity at 8 months interacted with their vocabulary size at 18 months. This interaction can be explained by the idea that infants with larger future vocabularies are more positively influenced by consistent training (and/or more negatively influenced by inconsistent training) than infants with smaller future vocabularies. This suggests that consistent pairing with distinct visual objects can help infants to discriminate speech sounds even when the auditory information does not signal a distinction. Together our results give computational as well as experimental support for the idea that semantic context plays a role in disambiguating

  10. Experimental evidence for the thermophilicity of ancestral life

    PubMed Central

    Akanuma, Satoshi; Nakajima, Yoshiki; Yokobori, Shin-ichi; Kimura, Mitsuo; Nemoto, Naoki; Mase, Tomoko; Miyazono, Ken-ichi; Tanokura, Masaru; Yamagishi, Akihiko

    2013-01-01

    Theoretical studies have focused on the environmental temperature of the universal common ancestor of life with conflicting conclusions. Here we provide experimental support for the existence of a thermophilic universal common ancestor. We present the thermal stabilities and catalytic efficiencies of nucleoside diphosphate kinases (NDK), designed using the information contained in predictive phylogenetic trees, that seem to represent the last common ancestors of Archaea and of Bacteria. These enzymes display extreme thermal stabilities, suggesting thermophilic ancestries for Archaea and Bacteria. The results are robust to the uncertainties associated with the sequence predictions and to the tree topologies used to infer the ancestral sequences. Moreover, mutagenesis experiments suggest that the universal ancestor also possessed a very thermostable NDK. Because, as we show, the stability of an NDK is directly related to the environmental temperature of its host organism, our results indicate that the last common ancestor of extant life was a thermophile that flourished at a very high temperature. PMID:23776221

  11. Convergent Evidence Scaling for Multiple Assessment Indicators: Conceptual Issues, Applications, and Technical Challenges

    ERIC Educational Resources Information Center

    Busse, R. T.; Elliott, Stephen N.; Kratochwill, Thomas R.

    2010-01-01

    The purpose of this article is to present Convergent Evidence Scaling (CES) as an emergent method for combining data from multiple assessment indicators. The CES method combines single-case assessment data by converging data gathered across multiple persons, settings, or measures, thereby providing an overall criterion-referenced outcome on which…

  12. Mining experimental evidence of molecular function claims from the literature

    PubMed Central

    Crangle, Colleen E.; Cherry, J. Michael; Hong, Eurie L.; Zbyslaw, Alex; Wong, Limsoon

    2011-01-01

    Motivation The rate at which gene-related findings appear in the scientific literature makes it difficult if not impossible for biomedical scientists to keep fully informed and up to date. The importance of these findings argues for the development of automated methods that can find, extract and summarize this information. This article reports on methods for determining the molecular function claims that are being made in a scientific article, specifically those that are backed by experimental evidence. Results The most significant result is that for molecular function claims based on direct assays, our methods achieved recall of 70.7% and precision of 65.7%. Furthermore, our methods correctly identified in the text 44.6% of the specific molecular function claims backed up by direct assays, but with a precision of only 0.92%, a disappointing outcome that led to an examination of the different kinds of errors. These results were based on an analysis of 1823 articles from the literature of Saccharomyces cerevisiae (budding yeast). Availability The annotation files for S.cerevisiae are available from ftp://genome-ftp.stanford.edu/pub/yeast/data_download/literature_curation/gene_association.sgd.gz. The draft protocol vocabulary is available by request from the first author. Contact crangle@converspeech.com PMID:17942445

  13. 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

  14. Experimental evidence for bedrock erosion by suspended sediment

    NASA Astrophysics Data System (ADS)

    Scheingross, J. S.; Brun, F.; Lo, D. Y.; Omerdin, K.; Lamb, M. P.

    2013-12-01

    Fluvial bedrock incision influences channel evolution and sets the pace of landscape lowering. Bedrock incision often occurs via abrasion, and existing theory is divided on the erosional efficiency of sediment transported in suspension versus bed load, due in part to a lack of data to test model predictions. This represents a major knowledge gap as suspended sediment can account for the majority of the total fluvial sediment load, and untested models make opposite predictions of bedrock erosion in steep channels and during large floods. We performed controlled abrasion mill experiments examining suspended and bed load erosion, making use of an erodible polyurethane foam substrate as a bedrock analog to overcome previous experimental limitations and allow for measureable suspension erosion. Our results show foam erodes similar to natural rock, where erodibility is a function of tensile strength and density. To explore the role of the mode of sediment transport on erosion, we varied sediment size from gravel (42 mm diameter) to medium sand (0.4 mm diameter), while holding fixed hydraulics, sediment load, and substrate strength. Under these conditions, volumetric erosion rates decreased across the bed load (~101 - 103 cm3/hr) to suspended load (~0.01 - 100 cm3/hr) transition due to lower near-bed sediment concentrations (~25 g/l vs. 115 g/l), slower settling velocity (0.09 m/s vs. 0.49 m/s), and viscous damping of impacts (for particle Stokes numbers less than ~75) for suspended particles. Our results provide direct experimental evidence of erosion by suspended load, and upscaling results to field scale shows suspension erosion can outpace bed load erosion by up to a factor ~4 during large floods which suspend coarse sand and gravel, and where suspended sediment dominates the total load. These results imply that suspension erosion may also dominate on very steep slopes where commonly used bedrock incision models (which ignore suspension erosion) predict zero erosion

  15. 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. PMID:19074573

  16. 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

  17. 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

  18. 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

  19. Gender differences in cooperation: experimental evidence on high school students.

    PubMed

    Molina, J Alberto; Giménez-Nadal, J Ignacio; Cuesta, José A; Gracia-Lazaro, Carlos; Moreno, Yamir; Sanchez, Angel

    2013-01-01

    The emergence of cooperation among unrelated human subjects is a long-standing conundrum that has been amply studied both theoretically and experimentally. Within the question, a less explored issue relates to the gender dependence of cooperation, which can be traced back to Darwin, who stated that "women are less selfish but men are more competitive". Indeed, gender has been shown to be relevant in several game theoretical paradigms of social cooperativeness, including prisoner's dilemma, snowdrift and ultimatum/dictator games, but there is no consensus as to which gender is more cooperative. We here contribute to this literature by analyzing the role of gender in a repeated Prisoners' Dilemma played by Spanish high-school students in both a square lattice and a heterogeneous network. While the experiment was conducted to shed light on the influence of networks on the emergence of cooperation, we benefit from the availability of a large dataset of more 1200 participants. We applied different standard econometric techniques to this dataset, including Ordinary Least Squares and Linear Probability models including random effects. All our analyses indicate that being male is negatively associated with the level of cooperation, this association being statistically significant at standard levels. We also obtain a gender difference in the level of cooperation when we control for the unobserved heterogeneity of individuals, which indicates that the gender gap in cooperation favoring female students is present after netting out this effect from other socio-demographics factors not controlled for in the experiment, and from gender differences in risk, social and competitive preferences. PMID:24367608

  20. Rotational grazing on rangelands: Reconciliation of perception and experimental evidence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The experimental evaluation of grazing systems represents a highly visible and lengthy chapter in the history of the rangeland profession. Although experimentation has largely concluded, contrasting interpretations still remain regarding the potential benefits of rotational grazing systems on rangel...

  1. Evidence-Based Development and Rationale for Once-Daily Rivaroxaban Dosing Regimens Across Multiple Indications

    PubMed Central

    Berkowitz, Scott D.; Misselwitz, Frank

    2016-01-01

    Background: Rivaroxaban, a direct factor Xa inhibitor, has been developed to meet clinical needs in a broad range of indications in adults: prevention of venous thromboembolism after elective hip or knee replacement surgery, treatment and secondary prevention of venous thromboembolism, prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation having one or more risk factors, and in Europe, prevention of atherothrombotic events after an acute coronary syndrome in patients with elevated cardiac biomarkers. However, the precise dose and regimen vary with the indication, leading to this effort to provide clarity concerning the appropriate use of rivaroxaban. This article reviews the clinical development program for rivaroxaban and summarizes the evidence for each approved, indication-specific dose regimen. Results: Although initially investigated for twice-daily dosing, early observations, including the finding that the pharmacodynamic effects of rivaroxaban last longer than the elimination half-life, suggested that once-daily dosing might be attainable and effective. These observations were evaluated within the extensive phase II program, which, together with pharmacology studies, provides the evidence underpinning the selection of once-daily regimens for most, but not all, of the approved clinical indications for rivaroxaban. Conclusion: The evidence for each dosing regimen demonstrates that although pharmacology studies are of paramount importance, dose regimens must be subjected to careful empirical validation. Once-daily dosing was shown to be clinically appropriate for most rivaroxaban indications. Furthermore, a “one size fits all” approach to dosing frequency is unlikely to result in a regimen that yields optimal patient outcomes across different indications. PMID:26893445

  2. Experimental Perturbations Modify the Performance of Early Warning Indicators of Regime Shift.

    PubMed

    Benedetti-Cecchi, Lisandro; Tamburello, Laura; Maggi, Elena; Bulleri, Fabio

    2015-07-20

    Ecosystems may shift abruptly between alternative states in response to environmental perturbations. Early warning indicators have been proposed to anticipate such regime shifts, but experimental field tests of their validity are rare. We exposed rocky intertidal algal canopies to a gradient of press perturbations and recorded the response of associated assemblages over 7 years. Reduced cover and biomass of algal canopies promoted the invasion of algal turfs, driving understory assemblages toward collapse upon total canopy removal. A dynamic model indicated the existence of a critical threshold separating the canopy- and turf-dominated states. We evaluated common indicators of regime shift as the system approached the threshold, including autocorrelation, SD, and skewness. These indicators captured changes in understory cover due to colonization of algal turfs. All indicators increased significantly as the system approached the critical threshold, in agreement with theoretical predictions. The performance of indicators changed when we superimposed a pulse disturbance on the press perturbation that amplified environmental noise. This treatment caused several experimental units to switch repeatedly between the canopy- and the turf-dominated state, resulting in a significant increase in overall variance of understory cover, a negligible effect on skewness and no effect on autocorrelation. Power analysis indicated that autocorrelation and SD were better suited at anticipating a regime shift under mild and strong fluctuations of the state variable, respectively. Our results suggest that regime shifts may be anticipated under a broad range of fluctuating conditions using the appropriate indicator. PMID:26166776

  3. Intraoperative radiotherapy in early stage breast cancer: potential indications and evidence to date

    PubMed Central

    Kirby, A M

    2015-01-01

    Following early results of recent studies of intraoperative radiotherapy (IORT) in the adjuvant treatment of patients with early breast cancer, the clinical utility of IORT is a subject of much recent debate within the breast oncology community. This review describes the intraoperative techniques available, the potential indications and the evidence to date pertaining to local control and toxicity. We also discuss any implications for current practice and future research. PMID:25734489

  4. Performance Indicators in Math: Implications for Brief Experimental Analysis of Academic Performance

    ERIC Educational Resources Information Center

    VanDerheyden, Amanda M.; Burns, Matthew K.

    2009-01-01

    Brief experimental analysis (BEA) can be used to specify intervention characteristics that produce positive learning gains for individual students. A key challenge to the use of BEA for intervention planning is the identification of performance indicators (including topography of the skill, measurement characteristics, and decision criteria) that…

  5. Auger Recombination in Indium Gallium Nitride: Experimental Evidence

    NASA Astrophysics Data System (ADS)

    Krames, Michael

    2010-03-01

    Progress in InGaN-based light-emitting diode (LED) technology has resulted in white-light emitters with efficiencies far exceeding those of conventional light sources such as tungsten-filament-based incandescence and mercury-vapor based fluorescence. Indeed, by now efficacies exceeding 150 lumens per Watt for InGaN-based phosphor-converted white LEDs are claimed, which represent a 90% energy savings compared to the conventional incandescent (i.e., ``light bulb'') solution. However, these high performance levels are obtained under conditions of very low forward current-density for the InGaN LED and do not represent true operating conditions (nor cost-effective utilization) for the device. In order to reduce the cost (and thus increase market penetration of) solid-state lighting, more lumens per unit of semiconductor area are required which in practice necessitates higher drive current densities. Unfortunately, at these higher driver current densities, the internal quantum efficiency of InGaN-based LEDs is observed to decrease significantly. In the fall of 2007, researchers at the Advanced Laboratories of Philips Lumileds were the first to propose Auger recombination as the root-cause mechanism in InGaN which was behind this ``efficiency droop'' [1]. They further proposed to circumvent the problem by employing InGaN-based active region designs that maintain low carrier density, and demonstrated an LED device design that reaches a maximum quantum efficiency above 200 A/cm2, compared to ˜1-10 A/cm^2 for typical multiple-quantum-well heterostructures [2]. In this talk we will review the experimental evidence for Auger recombination in InGaN, beginning with the early work from 2007 and then considering additional work from more recent efforts to better understand the details behind this loss mechanism. [4pt] [1] Y. C. Shen, G. O. M"uller, S. Watanabe, N. F. Gardner, A. Munkholm, and M. R. Krames, ``Auger recombination in InGaN measured by photoluminescence'', Appl. Phys

  6. Experimental Shock Transformation of Gypsum to Anhydrite: A New Low Pressure Regime Shock Indicator

    NASA Technical Reports Server (NTRS)

    Bell, Mary S.; Zolensky, Michael E.

    2011-01-01

    The shock behavior of gypsum is important in understanding the Cretaceous/Paleogene event and other terrestrial impacts that contain evaporite sediments in their targets (e.g., Mars Exploration Rover Spirit detected sulfate at Gusev crater, [1]). Most interest focuses on issues of devolatilization to quantify the production of SO2 to better understand its role in generating a temporary atmosphere and its effects on climate and biota [2,3]. Kondo and Ahrens [4] measured induced radiation emitted from single crystal gypsum shocked to 30 and 40 GPa. They observed greybody emission spectra corresponding to temperatures in the range of 3,000 to 4,000 K that are a factor of 2 to 10 times greater than calculated pressure-density energy equation of state temperatures (Hugoniot) and are high enough to melt gypsum. Chen et al. [5] reported results of shock experiments on anhydrite, gypsum, and mixtures of these phases with silica. Their observations indicated little or no devolatilization of anhydrite shocked to 42 GPa and that the fraction of sulfur, by mass, that degassed is approx.10(exp -2) of theoretical prediction. In another report of shock experiments on calcite, anhydrite, and gypsum, Badjukov et al. [6] observed only intensive plastic deformation in anhydrite shock loaded at 63 GPa, and gypsum converted to anhydrite when shock loaded at 56 GPa but have not experimentally shocked gypsum in a step-wise manner to constrain possible incipient transformation effects. Schmitt and Hornemann [7] shock loaded anhydrite and quartz to a peak pressure of 60 GPa and report the platy anhydrite grains were completely pseudomorphed by small crystallized anhydrite grains. However, no evidence of interaction between the two phases could be observed and they suggested that recrystallization of anhydrite grains is the result of a solid-state transformation. They concluded that significant decomposition of anhydrite requires shock pressures higher than 60 GPa. Gupta et al. [8

  7. Assessing the Relationship between Vector Indices and Dengue Transmission: A Systematic Review of the Evidence

    PubMed Central

    Bowman, Leigh R.; Runge-Ranzinger, Silvia; McCall, P. J.

    2014-01-01

    Background Despite doubts about methods used and the association between vector density and dengue transmission, routine sampling of mosquito vector populations is common in dengue-endemic countries worldwide. This study examined the evidence from published studies for the existence of any quantitative relationship between vector indices and dengue cases. Methodology/Principal Findings From a total of 1205 papers identified in database searches following Cochrane and PRISMA Group guidelines, 18 were included for review. Eligibility criteria included 3-month study duration and dengue case confirmation by WHO case definition and/or serology. A range of designs were seen, particularly in spatial sampling and analyses, and all but 3 were classed as weak study designs. Eleven of eighteen studies generated Stegomyia indices from combined larval and pupal data. Adult vector data were reported in only three studies. Of thirteen studies that investigated associations between vector indices and dengue cases, 4 reported positive correlations, 4 found no correlation and 5 reported ambiguous or inconclusive associations. Six out of 7 studies that measured Breteau Indices reported dengue transmission at levels below the currently accepted threshold of 5. Conclusions/Significance There was little evidence of quantifiable associations between vector indices and dengue transmission that could reliably be used for outbreak prediction. This review highlighted the need for standardized sampling protocols that adequately consider dengue spatial heterogeneity. Recommendations for more appropriately designed studies include: standardized study design to elucidate the relationship between vector abundance and dengue transmission; adult mosquito sampling should be routine; single values of Breteau or other indices are not reliable universal dengue transmission thresholds; better knowledge of vector ecology is required. PMID:24810901

  8. Comparison of ordered and disordered silicon nanowire arrays: experimental evidence of photonic crystal modes.

    PubMed

    Dhindsa, Navneet; Saini, Simarjeet S

    2016-05-01

    We experimentally compared the reflectance between ordered and disordered silicon nanowires to observe the evidence of photonic crystal modes. For similar diameters, the resonance peaks for the ordered nanowires at a spacing of 400 nm was at a shorter wavelength than the disordered nanowires, consistent to the excitation of photonic crystal modes. Furthermore, the resonant wavelength didn't shift while changing the density of the disordered nanowires, whereas there was a significant shift observed in the ordered ones. At an ordered spacing of 800 nm, the resonance wavelength approached that of the disordered structures, indicating that the ordered structures were starting to behave like individual waveguides. To our knowledge, this is the first direct experimental observation of photonic crystal modes in vertical periodic silicon nanowire arrays. PMID:27128070

  9. Education and Cognitive Development: The Evidence from Experimental Research.

    ERIC Educational Resources Information Center

    Sharp, Donald; And Others

    1979-01-01

    Reports the results of a series of experimental studies and a sociodemographic survey designed to determine the relative influence of age and educational experience in the development of cognitive skills as manifested in formal, psychological experiments. (CM)

  10. Non-Respiratory Indications for Polysomnography and Related Procedures in Children: An Evidence-Based Review

    PubMed Central

    Kotagal, Suresh; Nichols, Cynthia D.; Grigg-Damberger, Madeleine M.; Marcus, Carole L.; Witmans, Manisha B.; Kirk, Valerie G.; D'Andrea, Lynn A.; Hoban, Timothy F.

    2012-01-01

    Objective: This evidence-based review provides a systematic and comprehensive review of the literature regarding the utility of polysomnography for the evaluation of non-respiratory sleep disorders in children including hypersomnias, parasomnias, sleep-related movement disorders, and sleep in other special populations. Methods: A task force of pediatric sleep medicine experts performed a systematic review of the literature regarding the use of polysomnography for non-respiratory sleep disorders in children. They identified and graded 76 papers as evidence. Results: The main results include (1) polysomnography combined with the multiple sleep latency test is useful for evaluating disorders of excessive somnolence to objectively quantify sleepiness. The results have to be interpreted with consideration of the pubertal stage and regularity of the sleep patterns of the child; (2) polysomnography is indicated in children with parasomnias or sleep related movement disorders who have a high likelihood of having obstructive sleep apnea (OSA); (3) polysomnography is not routinely indicated in children with enuresis unless there is a high likelihood of OSA; (4) polysomnography can be helpful in evaluating children with restless legs syndrome (RLS) and when periodic limb movement disorder (PLMD) is suspected. Conclusions: These findings suggest that, in children with non-respiratory sleep disorders, polysomnography should be a part of a comprehensive sleep evaluation in selected circumstances to determine the nature of the events in more detail or when the suspicion of OSA is relatively high. Citation: Kotagal S; Nichols CD; Grigg-Damberger MM; Marcus CL; Witmans MB; Kirk VG; D'Andrea LA; Hoban TF. Non-respiratory indications for polysomnography and related procedures in children: an evidence-based review. SLEEP 2012;35(11):1451-1466. PMID:23115394

  11. Experimental evidence of antiphase population dynamics in lasers

    SciTech Connect

    Cabrera, Eduardo; Calderon, Oscar G.; Guerra, J.M.

    2005-10-15

    We report a direct experimental observation of antiphase oscillations in population dynamics in lasers. We show that these population oscillations are intrinsically related to the well-known antiphase polarization dynamics, i.e., the antiphase oscillations of two orthogonal polarization laser field states. We have used a class B Nd:YAG (yttrium aluminum garnet) laser.

  12. Bilateral oligopoly in pollution permit markets - experimental evidence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  13. Bilateral oligopoly in pollution permit markets: experimental evidence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  14. Is the Readmission Rate a Valid Quality Indicator? A Review of the Evidence

    PubMed Central

    Fischer, Claudia; Lingsma, Hester F.; Marang-van de Mheen, Perla J.; Kringos, Dionne S.; Klazinga, Niek S.; Steyerberg, Ewout W.

    2014-01-01

    Introduction Hospital readmission rates are increasingly used for both quality improvement and cost control. However, the validity of readmission rates as a measure of quality of hospital care is not evident. We aimed to give an overview of the different methodological aspects in the definition and measurement of readmission rates that need to be considered when interpreting readmission rates as a reflection of quality of care. Methods We conducted a systematic literature review, using the bibliographic databases Embase, Medline OvidSP, Web-of-Science, Cochrane central and PubMed for the period of January 2001 to May 2013. Results The search resulted in 102 included papers. We found that definition of the context in which readmissions are used as a quality indicator is crucial. This context includes the patient group and the specific aspects of care of which the quality is aimed to be assessed. Methodological flaws like unreliable data and insufficient case-mix correction may confound the comparison of readmission rates between hospitals. Another problem occurs when the basic distinction between planned and unplanned readmissions cannot be made. Finally, the multi-faceted nature of quality of care and the correlation between readmissions and other outcomes limit the indicator's validity. Conclusions Although readmission rates are a promising quality indicator, several methodological concerns identified in this study need to be addressed, especially when the indicator is intended for accountability or pay for performance. We recommend investing resources in accurate data registration, improved indicator description, and bundling outcome measures to provide a more complete picture of hospital care. PMID:25379675

  15. 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. PMID:19484211

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Word population analysis and other evidences indicate that Shiji was amended by Liu Xiang

    NASA Astrophysics Data System (ADS)

    Chi, Ting-Ting; Wang, Shih-Chieh; Hu, Chin-Kun

    2015-11-01

    Shiji prepared by Shima Qian in Western Han Dynasty (202 BC-9 AD) was the most famous historical book in historical China. The current version of Shiji contains 130 chapters, including 10 chapters which contains some parts starting with the sentence "Mr. Chu said …"; such parts were considered to be written by Chu Shaosun by Chang Yen in the Three Kingdoms Period (220-280 AD), which was widely accepted. We have analyzed the word population in Shiji and books written by Liu Xiang (77 BC-6 BC) in Western Han Dynasty, who was a member of the royal family. Our results and other evidences indicate that the parts of Shiji starting with the sentence "Mr. Chu said …" were prepared by Liu Xiang. The other evidences include (1) The ending year of the events mentioned in "Mr. Chu said..." was considered to be 47 BC, the second year of Emperor Yuan (as Emperor in 48 BC-32 BC) of Western Han Dynasty, and in the same year Liu Xiang was put into a jail, then left power center for many years. Such coincidence suggests that Liu Xiang wrote the parts "Mr. Chu said …" in Shiji. (2) Liu Xiang's education, interest, and writings are quite consistent with the parts with "Mr. Chu said …" in Shiji. On the other hand, one cannot find such a connection with Chu Shaosun, who did not have any other identified writings for comparison.

  18. 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

  19. 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

  20. Fostering Early Math Comprehension: Experimental Evidence from Paraguay

    ERIC Educational Resources Information Center

    Naslund-Hadley, Emma; Parker, Susan W.; Hernandez-Agramonte, Juan Manuel

    2014-01-01

    Research indicates that preschool children need to learn pre-math skills to build a foundation for primary- and secondary-level mathematics. This paper presents the results from the early stages of a pilot mathematics program implemented in Cordillera, Paraguay. In a context of significant gaps in teacher preparation and pedagogy, the program uses…

  1. Experimental evidence of warm electron populations in magnetron sputtering plasmas

    SciTech Connect

    Sahu, B. B. Han, Jeon G.; Kim, Hye R.; Ishikawa, K.; Hori, M.

    2015-01-21

    This work report on the results obtained using the Langmuir probe (LP) measurements in high-power dc magnetron sputtering discharges. Data show clear evidence of two electron components, such as warm and bulk electrons, in the sputtering plasma in a magnetic trap. We have also used optical emission spectroscopy diagnostic method along with LP to investigate the plasma production. Data show that there is a presence of low-frequency oscillations in the 2–3 MHz range, which are expected to be generated by high-frequency waves. Analysis also suggests that the warm electrons, in the plasmas, can be formed due to the collisionless Landau damping of the bulk electrons.

  2. Experimental evidence for a dynamical crossover in liquid aluminium.

    PubMed

    Demmel, F; Fraile, A; Szubrin, D; Pilgrim, W-C; Morkel, C

    2015-11-18

    The temperature dependence of the dynamic structure factor at next-neighbour distances has been investigated for liquid aluminium. This correlation function is a sensitive parameter for changes in the local environment and its Fourier transform was measured in a coherent inelastic neutron scattering experiment. The zero frequency amplitude decreases in a nonlinear way and indicates a change in dynamics around 1.4 ∙ Tmelting. From that amplitude a generalized viscosity can be derived which is a measure of local stress correlations on next-neighbour distances. The derived generalized longitudinal viscosity shows a changing slope at the same temperature range. At this temperature the freezing out of degrees of freedom for structural relaxation upon cooling sets in which can be understood as a precursor towards the solid state. That crossover in dynamics of liquid aluminium shows the same signatures as previously observed in liquid rubidium and lead, indicating an universal character. PMID:26465204

  3. Experimental evidence for a dynamical crossover in liquid aluminium

    NASA Astrophysics Data System (ADS)

    Demmel, F.; Fraile, A.; Szubrin, D.; Pilgrim, W.-C.; Morkel, C.

    2015-11-01

    The temperature dependence of the dynamic structure factor at next-neighbour distances has been investigated for liquid aluminium. This correlation function is a sensitive parameter for changes in the local environment and its Fourier transform was measured in a coherent inelastic neutron scattering experiment. The zero frequency amplitude decreases in a nonlinear way and indicates a change in dynamics around 1.4\\cdot {{T}\\text{melting}} . From that amplitude a generalized viscosity can be derived which is a measure of local stress correlations on next-neighbour distances. The derived generalized longitudinal viscosity shows a changing slope at the same temperature range. At this temperature the freezing out of degrees of freedom for structural relaxation upon cooling sets in which can be understood as a precursor towards the solid state. That crossover in dynamics of liquid aluminium shows the same signatures as previously observed in liquid rubidium and lead, indicating an universal character.

  4. Experimental evidence for paternal effects on offspring growth rate in Arctic charr (Salvelinus alpinus)

    PubMed Central

    Eilertsen, Eirik Mack; Bårdsen, Bård-Jørgen; Liljedal, Ståle; Rudolfsen, Geir; Folstad, Ivar

    2008-01-01

    Sexual selection theory predicts that females should choose males that signal viability and quality. However, few studies have found fitness benefits among females mating with highly ornamented males. Here, we use Arctic charr (Salvelinus alpinus), a teleost fish with no parental care, to investigate whether females could gain fitness benefits by mating with highly ornamented and large-sized males. Carotenoid-based coloration signalled by males during spawning is believed to be an indicator of good genes for this species. Paternal effects on offspring size (body length and dry body mass) were examined experimentally by crossing eggs and sperm in vitro from 12 females and 24 males in a split-brood design and raising larvae to 30 days past hatching. We clearly demonstrated that there was a relationship between offspring size and paternal coloration. However, a negative interaction between paternal length and coloration was evident for offspring length, indicating that positive effects of paternal coloration were only present for smaller males. Thus, the red spawning coloration of the male Arctic charr seems to be an indicator of good genes, but the effect of paternal coloration on offspring length, an indicator of ‘offspring quality’, is size dependent. PMID:18782751

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

    PubMed

    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

  6. 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

  7. Experimental evidence for radiation pressure on a macroscopic dielectric

    NASA Astrophysics Data System (ADS)

    García-Segundo, C.; Ramos-Ortiz, G.; Villagrán-Muniz, M.

    2003-09-01

    We have detected acoustic signals produced by laser pulses on a macroscopic glass slab, obtaining amplitudes, as function of the angle of incidence, denoted as Hp and Hs depending on the polarization orientations of the pulsed pumping laser, p and s, respectively. The relative behaviour of these curves is related to radiation pressure rather than pure absorption, in the same manner as predicted theoretically in the literature [A Treatise on Electricity and Magnetism, Dover Publications, New York, 1891; Phys. Rep. 52 (1979) 133; Opt. Commun. 58 (1986) 59]. In a second experiment, based on a CW Michelson interferometer, where one of the mirrors is a glass slab pumped at the Brewster angle with the pulsed beam, we verified qualitatively the relationship observed for the Hp and Hs acoustic experimental data.

  8. 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

  9. Experimental Evidence of Fermi-Luttinger Liquid State.

    NASA Astrophysics Data System (ADS)

    Debray, Philippe; Muhammad, Mustafa; Herbert, Steven; Newrock, Richard

    2008-03-01

    We have measured Coulomb drag between spatially separated parallel quantum wires, made on AlGaAs/GaAs heterostructures by the split-gate technique, in the absence of tunneling to experimentally probe drag by small forward momentum transfer. Drag between wires of lengths 500 and 300 nm was measured in the one-dimensional transport regime at temperatures in the range 30 mK -- 1.2 K. We have observed both positive and negative drag. The temperature dependence of drag of both types is in excellent agreement with that predicted by the recently proposed Fermi-Luttinger liquid (FLL) theory that takes into account the curvature in the fermionic dispersion. Positive drag occurs when the curvature is positive, while negative drag occurs when it is negative.

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

    PubMed

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

    2015-07-01

    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. PMID:26138970

  11. Experimental evidence of homonuclear bonds in amorphous GaN

    SciTech Connect

    Ishimaru, Dr. Manabu; Zhang, Yanwen; Wang, Xuemei; Chu, Wei-Kan; Weber, William J

    2011-01-01

    Although GaN is an important semiconductor material, its amorphous structures are not well understood. Currently, theoretical atomistic structural models which contradict each other, are proposed for the chemical short-range order of amorphous GaN: one characterizes amorphous GaN networks as highly chemically ordered, consisting of heteronuclear Ga-N atomic bonds; and the other predicts the existence of a large number of homonuclear bonds within the first coordination shell. In the present study, we examine amorphous structures of GaN via radial distribution functions obtained by electron diffraction techniques. The experimental results demonstrate that amorphous GaN networks consist of heterononuclear Ga-N bonds, as well as homonuclear Ga-Ga and N-N bonds.

  12. Insight of scent: experimental evidence of olfactory capabilities in the wandering albatross (Diomedea exulans).

    PubMed

    Mardon, J; Nesterova, A P; Traugott, J; Saunders, S M; Bonadonna, F

    2010-02-15

    Wandering albatrosses routinely forage over thousands of kilometres of open ocean, but the sensory mechanisms used in the food search itself have not been completely elucidated. Recent telemetry studies show that some spatial behaviours of the species are consistent with the 'multimodal foraging strategy' hypothesis which proposes that birds use a combination of olfactory and visual cues while foraging at sea. The 'multimodal foraging strategy' hypothesis, however, still suffers from a lack of experimental evidence, particularly regarding the olfactory capabilities of wandering albatrosses. As an initial step to test the hypothesis, we carried out behavioural experiments exploring the sensory capabilities of adult wandering albatrosses at a breeding colony. Three two-choice tests were designed to investigate the birds' response to olfactory and visual stimuli, individually or in combination. Perception of the different stimuli was assessed by comparing the amount of exploration directed towards an 'experimental' display or a 'control' display. Our results indicate that birds were able to perceive the three types of stimulus presented: olfactory, visual and combined. Moreover, olfactory and visual cues were found to have additional effects on the exploratory behaviours of males. This simple experimental demonstration of reasonable olfactory capabilities in the wandering albatross supports the 'multimodal foraging strategy' and is consistent with recent hypotheses of the evolutionary history of procellariiforms. PMID:20118306

  13. Experimental evidence of energetic neutrals production in an ion diode

    NASA Astrophysics Data System (ADS)

    Pushkarev, A. I.; Isakova, Y. I.; Khaylov, I. P.

    2015-01-01

    The paper presents several experimental proofs of the formation of energetic charge-exchange neutrals in a self-magnetically insulated ion diode with a graphite cathode. The energetic neutrals are thought to be produced as a result of charge exchange process between accelerated ions and stationary neutral molecules. The experiments have been carried out using both a diode with externally applied magnetic insulation (single-pulse mode: 100 ns, 250-300 kV) and a diode with self-magnetic insulation (double-pulse mode: 300-500 ns, 100-150 kV (negative pulse); 120 ns, 250-300 kV (positive pulse)). The motivation for looking at the neutral component of the ion beam came when we compared two independent methods to measure the energy density of the beam. A quantitative comparison of infrared measurements with signals from Faraday cups and diode voltage was made to assess the presence of neutral atoms in the ion beam. As another proof of charge-exchange effects in ion diode we present the results of statistical analysis of diode performance. It was found that the shot-to shot variation of the energy density in a set of 50-100 shots does not exceed 11%, whilst the same variation for ion current density was 20-30%; suggesting the presence of neutrals in the beam. Moreover, the pressure in the zone of ion beam energy dissipation exceeds the results stated in cited references. The difference between our experimental data and results stated by other authors we attribute to the presence of a low-energy charge-exchange neutral component in the ion beam.

  14. Experimental evidence of indirect transmission of Mycoplasma synoviae.

    PubMed

    Marois, Corinne; Picault, Jean-Paul; Kobisch, Marylène; Kempf, Isabelle

    2005-01-01

    The aim of the study was to analyse experimental transmission of Mycoplasma synoviae, an avian pathogen. Three experiments using specific pathogen-free day-old chicks placed in isolators were conducted. In the first experiment, the birds were introduced in an isolator previously contaminated with a M. synoviae broth culture. After 34 days, these birds were eliminated and, for the second trial, the chicks were introduced in the same isolator without disinfecting. In the third assay, the chicks were placed in an isolator containing a mixture of food, feathers and dust collected less than an hour earlier from a M. synoviae infected laying hen flock. In the second and third experiments in order to exacerbate the M. synoviae infection, the birds were inoculated with infectious bronchitis (IB) virus. The presence of M. synoviae in the environment and in tracheal swabs was monitored by culture, a multiplex PCR (mPCR) detecting M. synoviae and Mycoplasma 16S rDNA and a multiplex RT-PCR (mRT-PCR) detecting the M. synoviae mRNA coding for a membrane protein and Mycoplasma 16S rRNA. In in vitro experimental conditions, M. synoviae mRNA and 16S rRNA were detected up to 20 min and 23 h respectively after mycoplasma death. In the first assay, the first infected bird was detected on the 13th day. In the second trial, culturable M. synoviae or viable M. synoviae were detected in the isolator for 3 or 4 to 5 days respectively after depopulation of the birds of the first assay whereas the first culture positive tracheal swabs were detected on the 33rd day, after IB inoculation. In the third experiment, the first infected birds were detected on the 54th day. Thus, the different assays showed that M. synoviae contaminated material (dust, feathers and food) can infect chicks, sometimes after remarkably long silent periods. PMID:16120251

  15. 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. PMID:17605588

  16. Experimental evidence from active placement efforts among unemployed in Sweden.

    PubMed

    Hägglund, Pathric

    2014-06-01

    This article uses data from a field experiment in Sweden to analyze the effects of active placement efforts. In particular, the relative efficiency between combining job-search monitoring and job-search assistance, and monitoring alone, is analyzed. Although the impact estimates are generally imprecisely estimated, a general conclusion is that placement programs are effective policies in increasing the job exit rate for various groups of unemployed. I find that monitoring of job search is an efficient method to increase off-unemployment exit rate both alone and combined with job-search assistance services. The results, however, indicate that the combined services generate more permanent job exits. PMID:25201049

  17. Experimental evidence of a delta-shock in nonlinear chromatography

    SciTech Connect

    Gritti, Fabrice; Guiochon, Georges A

    2010-01-01

    We report about a new type of composition front in nonlinear chromatography that is called delta-shock, which has to be added to the family of classical transitions, i.e. simple waves, shocks and semi-shocks. Recently, the occurrence of delta-shocks in the case of mixed competitive-cooperative isotherms of the following type n{sub i} = H{sub i}c{sub i}/1 = K{sub 1}c{sub 1} + K{sub 2}c{sub 2} (i = 1,2), (with H{sub 2} > H{sub 1}, where components 1 and 2 have anti-Langmuir and Langmuir adsorption behavior, respectively) was predicted theoretically and their behavior was analyzed in the frame of the equilibrium theory of chromatography. The delta-shock can be viewed as a growing traveling spike superimposed to the discontinuity separating the initial and the feed state, which propagates along the column at constant speed and constant rate of growth. In this work we complement these findings from an experimental point of view. The binary system consisting of phenetole (component 1) and 4-tert-butylphenol (component 2) in methanol-water (about 2:1, v/v) on a Zorbax 300StableBond-C18 column from Agilent has been shown, through a series of overloaded pulse experiments and of frontal analysis experiments with the pure compounds, to be subject to the competitive-cooperative isotherm of the type above, up to rather large concentrations. This system does exhibit adelta-shock when the operating conditions are chosen according to theory, namely when phenetole initially saturating the column is displaced by 4-tert-butylphenol, both at high concentrations (the minimum concentrations exhibiting a fully developed delta-shock in this series of experiments were c{sub 1} = 20 g/L and c{sub 2} = 75 g/L). The propagation of the delta-shock matches the theoretical predictions in terms of both the effect of concentration and the effect of column length. This is the first experimental observation ever of adelta-shock in chromatography. It is noteworthy that the proof of the occurrence of

  18. An Evidence-Based Review Literature About Risk Indicators and Management of Unknown-Origin Xerostomia

    PubMed Central

    Agha-Hosseini, Farzaneh; Moosavi, Mahdieh-Sadat

    2013-01-01

    This evidence-based article reviews risk indicators and management of unknown-origin xerostomia. Xerostomia and hyposalivation refer to different aspects of dry mouth. Xerostomia is a subjective sensation of dry mouth, whilst hyposalivation is defined as an objective assessment of reduced salivary flow rate. About 30% of the elderly (65 years and older) experience xerostomia and hyposalivation. Structural and functional factors, or both may lead to salivary gland dysfunction. The EBM literature search was conducted by using the medical literature database MEDLINE via PubMed and OvidMedline search engines. Results were limited to English language articles (1965 to present) including clinical trials (CT), randomized controlled trials (RCT), systematic reviews and review articles. Case control or cohort studies were included for the etiology. Neuropathic etiology such as localized oral alteration of thermal sensations, saliva composition change (for example higher levels of K, Cl, Ca, IgA, amylase, calcium, PTH and cortisol), lower levels of estrogen and progesterone, smaller salivary gland size, and illnesses such as lichen planus, are risk indicators for unknown-origin xerostomia. The management is palliative and preventative. Management of symptoms includes drug administration (systemic secretogogues, saliva substitutes and bile secretion-stimulator), night guard, diet and habit modifications. Other managements may be indicated to treat adverse effects. Neuropathic etiology, saliva composition change, smaller salivary gland size, and illnesses such as oral lichen planus can be suggestive causes for unknown-origin xerostomia. However, longitudinal studies will be important to elucidate the causes of unknown-origin xerostomia. PMID:25512755

  19. Physical description of boundary-layer transition: Experimental evidence

    NASA Technical Reports Server (NTRS)

    Saric, William S.

    1994-01-01

    The problems of understanding the origins of turbulent flow and transition to turbulent flow are the most important unsolved problems of fluid mechanics and aerodynamics. It is well known that the stability, transition, and turbulent characteristics of bounded shear layers are fundamentally different from those of free shear layers. Likewise, the stability, transition, and turbulent characteristics of open systems are fundamentally different from those of closed systems. Because of the influence of indigenous disturbances, surface geometry and roughness, sound, heat transfer, and ablation, it is not possible to develop general prediction schemes for transition location and the nature of turbulent structures in boundary-layer flows. At the present time no mathematical model exists that can predict the transition Reynolds number on a flat plate. The recent progress in this area is encouraging, in that a number of distinct transition mechanisms have been found experimentally. The theoretical work finds them to be amplitude and Reynolds-number dependent. The theory remains rather incomplete with regard to predicting transition. Amplitude and spectral characteristics of the disturbances inside the laminar viscous layer strongly influence which type of transition occurs. The major need in this area is to understand how freestream disturbances are entrained into the boundary layer, i.e., to answer the question of receptivity. We refer receptivity to the mechanism(s) that cause freestream disturbances to enter the boundary layer and create the initial amplitudes for unstable waves.

  20. [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. PMID:24206254

  1. Experimental evidence for extreme dispersal limitation in tropical forest birds.

    PubMed

    Moore, R P; Robinson, W D; Lovette, I J; Robinson, T R

    2008-09-01

    Movements of organisms between habitat remnants can affect metapopulation structure, community assembly dynamics, gene flow and conservation strategy. In the tropical landscapes that support the majority of global biodiversity and where forest fragmentation is accelerating, there is particular urgency to understand how dispersal across habitats mediates the demography, distribution and differentiation of organisms. By employing unique dispersal challenge experiments coupled with exhaustive inventories of birds in a Panamanian lacustrine archipelago, we show that the ability to fly even short distances (< 100 m) between habitat fragments varies dramatically and consistently among species of forest birds, and that this variation correlates strongly with species' extinction histories and current distributions across the archipelago. This extreme variation in flight capability indicates that species' persistence in isolated forest remnants will be differentially mediated by their respective dispersal abilities, and that corridors connecting such fragments will be essential for the maintenance of avian diversity in fragmented tropical landscapes. PMID:18513315

  2. Frost-weathering on Mars - Experimental evidence for peroxide formation

    NASA Technical Reports Server (NTRS)

    Huguenin, R. L.; Miller, K. J.; Harwood, W. S.

    1979-01-01

    The weathering of silicates by frost is investigated in relation to the formation of surface peroxides to which Viking biology experiment results have been attributed. Samples of the minerals olivine and pyroxene were exposed to water vapor at -11 to -22 C and resultant gas evolution and pH were monitored. Experiments reveal the formation of an acidic oxidant upon interaction of the mineral and H2O frost at subfreezing temperatures, which chemical indicators have suggested to be chemisorbed hydrogen peroxide. A model for the formation of chemisorbed peroxide based on the chemical reduction of the mineral by surface frost is proposed, and it is predicted that the perioxide would decay at high temperatures to H2O and adsorbed O, consistent with the long-term storage and sterilization behavior of the soil oxidants observed in the Viking Gas Exchange and Labeled Release experiments.

  3. Dietary fibre and colon cancer: epidemiologic and experimental evidence.

    PubMed Central

    Reddy, B S

    1980-01-01

    Epidemiologic studies have identified two dietary factors, a relatively high intake of fat and a relatively low intake of fibre, that are associated with colon cancer in humans. However, a recent study has shown a low risk of large bowel cancer in a rural Finnish population with a high dietary intake of fat, but also a high intake of fibre. Observations in humans and studies in animals have indicated that dietary fibre may protect against colon carcinogenesis by binding bile acids in the intestinal tract, by a direct effect on the colonic mucosa and by an indirect effect on the metabolism of carcinogens. The strength of protection varies with the type of fibre. PMID:6254626

  4. Self-organization of trajectory formation. I. Experimental evidence.

    PubMed

    Buchanan, J J; Kelso, J A; de Guzman, G C

    1997-04-01

    Most studies examining the stability and change of patterns in biological coordination have focused on identifying generic bifurcation mechanisms in an already active set of components (see Kelso 1994). A less well understood phenomenon is the process by which previously quiescent degrees of freedom (df) are spontaneously recruited and active df suppressed. To examine such behavior, in part I we study a single limb system composed of three joints (wrist, elbow, and shoulder) performing the kinematically redundant task of tracing a sequence of two-dimensional arcs of monotonically varying curvature, kappa. Arcs were displayed on a computer screen in a decreasing and increasing kappa sequence, and subjects rhythmically traced the arcs with the right hand in the sagittal plane at a fixed frequency (1.0 Hz), with motion restricted to flexion-extension of the wrist, elbow, and shoulder. Only a few coordinative patterns among the three joints were stably produced, e.g., in-phase (flexion-extension of one joint coordinated with flexion-extension of another joint) and antiphase (flexion-extension coordinated with extension-flexion). As kappa was systematically increased and decreased, switching between relative phase patterns was observed around critical curvature values, kappa c. A serendipitous finding was a strong 2:1 frequency ratio between the shoulder and elbow that occurred across all curvature values for some subjects, regardless of the wrist-elbow relative phase pattern. Transitions from 1:1 to 2:1 frequency entrainment and vice versa were also observed. The results indicate that both amplitude modulation and relative phase change are utilized to stabilize the end-effector trajectory. In part II, a theoretical model is derived from three coupled nonlinear oscillators, in which the relative phases (phi) between the components and the relative joint amplitudes (rho) are treated as collective variables with arc curvature as a control parameter. PMID:9195743

  5. Non-monotonic Temporal-Weighting Indicates a Dynamically Modulated Evidence-Integration Mechanism.

    PubMed

    Bronfman, Zohar Z; Brezis, Noam; Usher, Marius

    2016-02-01

    Perceptual decisions are thought to be mediated by a mechanism of sequential sampling and integration of noisy evidence whose temporal weighting profile affects the decision quality. To examine temporal weighting, participants were presented with two brightness-fluctuating disks for 1, 2 or 3 seconds and were requested to choose the overall brighter disk at the end of each trial. By employing a signal-perturbation method, which deploys across trials a set of systematically controlled temporal dispersions of the same overall signal, we were able to quantify the participants' temporal weighting profile. Results indicate that, for intervals of 1 or 2 sec, participants exhibit a primacy-bias. However, for longer stimuli (3-sec) the temporal weighting profile is non-monotonic, with concurrent primacy and recency, which is inconsistent with the predictions of previously suggested computational models of perceptual decision-making (drift-diffusion and Ornstein-Uhlenbeck processes). We propose a novel, dynamic variant of the leaky-competing accumulator model as a potential account for this finding, and we discuss potential neural mechanisms. PMID:26866598

  6. Non-monotonic Temporal-Weighting Indicates a Dynamically Modulated Evidence-Integration Mechanism

    PubMed Central

    Usher, Marius

    2016-01-01

    Perceptual decisions are thought to be mediated by a mechanism of sequential sampling and integration of noisy evidence whose temporal weighting profile affects the decision quality. To examine temporal weighting, participants were presented with two brightness-fluctuating disks for 1, 2 or 3 seconds and were requested to choose the overall brighter disk at the end of each trial. By employing a signal-perturbation method, which deploys across trials a set of systematically controlled temporal dispersions of the same overall signal, we were able to quantify the participants’ temporal weighting profile. Results indicate that, for intervals of 1 or 2 sec, participants exhibit a primacy-bias. However, for longer stimuli (3-sec) the temporal weighting profile is non-monotonic, with concurrent primacy and recency, which is inconsistent with the predictions of previously suggested computational models of perceptual decision-making (drift-diffusion and Ornstein-Uhlenbeck processes). We propose a novel, dynamic variant of the leaky-competing accumulator model as a potential account for this finding, and we discuss potential neural mechanisms. PMID:26866598

  7. Naturally occurring muscle pain during exercise: assessment and experimental evidence.

    PubMed

    Cook, D B; O'Connor, P J; Eubanks, S A; Smith, J C; Lee, M

    1997-08-01

    The objectives were: (i) to present a method for assessing muscle pain during exercise, (ii) to provide reliability and validity data in support of the measurement tool, (iii) to test whether leg muscle pain threshold during exercise was related to a commonly used measure of pain threshold pain during test, (iv) to examine the relationship between pain and exertion ratings, (v) to test whether leg muscle pain is related to performance, and (vi) to test whether a large dose of aspirin would delay leg muscle pain threshold and/or reduce pain ratings during exercise. In study 1, seven females and seven males completed three 1-min cycling bouts at three different randomly ordered power outputs. Pain was assessed using a 10-point pain scale. High intraclass correlations (R from 0.88 to 0.98) indicated that pain intensity could be rated reliably using the scale. In study 2, 11 college-aged males (age 21.3 +/- 1.3 yr) performed a ramped (24 W.min-1) maximal cycle ergometry test. A button was depressed when leg muscle pain threshold was reached. Pain threshold occurred near 50% of maximal capacity: 50.3 (+/- 12.9% Wmax), 48.6 (+/- 14.8% VO2max), and 55.8 (+/- 12.9% RPEmax). Pain intensity ratings obtained following pain threshold were positively accelerating function of the relative exercise intensity. Volitional exhaustion was associated with pain ratings of 8.2 (+/- 2.5), a value most closely associated with the verbal anchor "very strong pain." In study 3, participants completed the same maximal exercise test as in study 2 as well as leg cycling at 60 rpm for 8 s at four randomly ordered power outputs (100, 150, 200, and 250 W) on a separate day. Pain and RPE ratings were significantly lower during the 8-s bouts compared to those obtained at the same power outputs during the maximal cycle test. The results suggest that noxious metabolites of muscle contraction play a role in leg muscle pain during exercise. In study 4, moderately active male subjects (N = 19) completed

  8. Infectivity of DWV associated to flower pollen: experimental evidence of a horizontal transmission route.

    PubMed

    Mazzei, Maurizio; Carrozza, Maria Luisa; 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

  9. Forensic Geopedology and Micropedology: New Indications and Lookouts from Pigs Experimental Burials.

    NASA Astrophysics Data System (ADS)

    Ern, Stephania Irmgard Elena; Trombino, Luca

    2013-04-01

    The role played by soil scientists in the modern forensic science is very real and important, above all in the crime scenes when buried remains, both strongly decomposed or skeletal, are found. Thanks to a PhD project on Forensic Geopedology, an interdisciplinary team of the Universities of Milano and Milano Bicocca, has been working for the last four years on several sets of experimental burials of pigs and piglets, in different soil types and for different times of burial, in order to get new evidences on environmental responses to the burial, including geopedological and micropedological aspects. The present work constitutes a conclusive synthesis of results emerged from comparative soil characterizations, listed as follow: - Grainsize analyses; - Determination of pH in H2O and KCl; - Total Nitrogen and Organic Carbon analyses: - Quantification of Available Phosphorous; - Determination of Cation Exchange Capacity and Base Saturation; - Analyses of Volatile Fatty Acids; - Scanning Electron Microscope and Energy Dispersive Spectroscopy analyses; - Petrographic Optical Microscope analyses (including thin sections descriptions). It is proposed a diachronic picture of the project where it is possible to follow the variability of significance of the different kinds of analyses carried out. The achieved results, especially when cross-checked, are very stimulating as regards the setting of analytical protocols for: - The determination of time since burial (TSB); - The discrimination between primary and secondary burials; - The identification of corpses concealments. All the analyses and different approaches discussed and addressed in this work require extreme care when applied to real forensic scenarios; however, the protocols tested can be a piece of a large and articulated puzzle that depicts the major forensic case studies in which Geopedology can be of help in solving problems or in answering some peculiar questions. It is important to understand that a science so

  10. 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.

  11. 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.

  12. Relationships among Measures as Empirical Evidence of Validity: Incorporating Multiple Indicators of Achievement and School Context

    ERIC Educational Resources Information Center

    Goldschmidt, Pete; Martinez, Jose Felipe; Niemi, David; Baker, Eva L.

    2007-01-01

    In this article we examine empirical evidence on the criterion, predictive, transfer, and fairness aspects of validity of a large-scale language arts performance assessment, referred to as the Performance Assignment (PA). We use multilevel models to avoid biased inferences that might result from the naturally nested data. Specifically, we examine…

  13. 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. PMID:25380741

  14. 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

  15. Experimental evidence for the formation of liquid saline water on Mars

    PubMed Central

    Fischer, Erik; Martínez, Germán M; Elliott, Harvey M; Rennó, Nilton O

    2014-01-01

    Evidence for deliquescence of perchlorate salts has been discovered in the Martian polar region while possible brine flows have been observed in the equatorial region. This appears to contradict the idea that bulk deliquescence is too slow to occur during the short periods of the Martian diurnal cycle during which conditions are favorable for it. We conduct laboratory experiments to study the formation of liquid brines at Mars environmental conditions. We find that when water vapor is the only source of water, bulk deliquescence of perchlorates is not rapid enough to occur during the short periods of the day during which the temperature is above the salts' eutectic value, and the humidity is above the salts' deliquescence value. However, when the salts are in contact with water ice, liquid brine forms in minutes, indicating that aqueous solutions could form temporarily where salts and ice coexist on the Martian surface and in the shallow subsurface. Key Points The formation of brines at Martian conditions was studied experimentally Bulk deliquescence from water vapor is too slow to occur diurnally on Mars Brines form in minutes when salts are placed in direct contact with ice PMID:25821267

  16. 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∘.

  17. 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. PMID:24889601

  18. Experimental evidence of dual emission in a negatively solvatochromic push-pull pyridinium derivative.

    PubMed

    Carlotti, B; Cesaretti, A; Fortuna, C G; Spalletti, A; Elisei, F

    2015-01-21

    We report here experimental evidence of dual emission in a cationic push-pull system (bearing a methyl pyridinium group as an electron acceptor and a diphenylamino group as an electron donor), which shows negative solvatochromism. An intriguing blue shift and enlargement of the fluorescence band upon increasing the solvent polarity have suggested a possible contribution of an upper excited state to the stationary emission. Ultrafast transient absorption has indeed revealed the presence of an intermediate transient species in some solvents. The investigation of the fluorescence properties at low temperatures and in the rigid matrix has given a clear indication of this additional emission at shorter wavelengths. Femtosecond up-conversion measurements have shown interesting rise-decay dynamics in the kinetics and two well distinguished emission bands characterized by different deactivations. A single isoemissive point in the time-resolved area-normalized spectra has unambiguously pointed out the presence of two consecutive emissive species: the locally excited and the intramolecular charge transfer excited states. PMID:25474173

  19. Field experimental evidence that stochastic processes predominate in the initial assembly of bacterial communities.

    PubMed

    Hao, Yi-Qi; Zhao, Xin-Feng; Zhang, Da-Yong

    2016-06-01

    To assess the relative importance of environmental selection, dispersal and stochastic processes in structuring ecological communities, we conducted a bacterial community assembly experiment using microcosms filled with sterile liquid medium under field conditions in the Inner Mongolian grasslands. Multiple replicate microcosms containing different carbon substrates were placed at nine locations across three spatial scales (10, 300 and 10 000 m distance between locations) in such a way that the environment of microcosms varies independently of the geographical distance. The operational taxonomic units within the experimental communities were assessed via the terminal restriction fragment length polymorphism techniques on the 10th and 17th days after the onset of the experiment. We found no evidence of distance decay in community similarity, and communities within a given location were more similar to each other regardless of environment than communities at other locations within the same spatial scale. Variance partitioning indicated that location explained more compositional variation in microbial communities than environment, particularly on the 17th day, despite that environment and location in combination could only explain less than half of the total variation. These results suggest that bacterial dispersal is not limited by distance in this experiment, and community assembly in microcosms is not environmentally determined but governed by stochastic processes. PMID:25809418

  20. Experimental evidence of O-H—S hydrogen bonding in supersonic jet

    NASA Astrophysics Data System (ADS)

    Biswal, Himansu S.; Chakraborty, Shamik; Wategaonkar, Sanjay

    2008-11-01

    Experimental evidence is presented for the O-H—S hydrogen bonding in the complexes of simple model compounds of methionine (dimethyl sulphide) and tyrosine (phenol, p-cresol, and 2-naphthol). The complexes were formed in the supersonic jet and were detected using resonantly enhanced multiphoton ionization spectroscopy. In all the complexes, the band origins for the S1-S0 electronic transition were redshifted relative to that of their respective monomers. The resonant ion depletion IR spectra of all the complexes show redshifts of 123-140 cm-1 in the O-H stretching frequency, indicating that the OH group acts as the hydrogen bond donor and sulfur as an acceptor. The density functional theory calculations also predict the stable structures in support of this and predict the redshifted O-H stretching frequency in the complex. The atoms-in-molecules and natural bond orbital calculations confirm the O-H—S hydrogen bonding interaction. The significant finding of this study is that the magnitudes of redshifts in the O-H stretch in the O-H—S hydrogen bonded complexes reported here are comparable to those reported for the O-H—O hydrogen bonded complexes where H2O acts as the H-bond acceptor, which suggests that the OH-S interaction is perhaps as strong as the OH-O interaction. To the best of our knowledge, this is the first such report on the O-H—S hydrogen bonded complexes.

  1. 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.

  2. Evidence for effects of chronic lead exposure on blood pressure in experimental animals: an overview

    SciTech Connect

    Victery, W.

    1988-06-01

    Information obtained in a number of experimental studies conducted over the last 40 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 effects on each study are reported. In several of the high-dose experiments, hypertension was observed, but nephrotoxicity of lead may have contributed to its development. Moreover, in other high-dose experiments, no hypertension was observed, and in at least one experiment, the evidence suggested that lead could reduce an elevated blood pressure. In contrast, the lower dose experiments consistently demonstrated a hypertensive effect. Overall, the data suggest a biphasic dose response. Establishment of an appropriate animal model to study blood pressure effects of lead will require careful assessment of dietary interactions with lead, unstressed blood pressure monitoring with standardized techniques, and documentation of biologically effective lead burden. Future research should examine lead exposure at more environmentally appropriate levels in order to determine the validity of associating this pollutant with blood pressure effects in human population.

  3. Electric field driven fractal growth in polymer electrolyte composites: Experimental evidence of theoretical simulations

    NASA Astrophysics Data System (ADS)

    Dawar, Anit; Chandra, Amita

    2012-11-01

    The influence of electric field on the diffusion limited aggregation has been observed experimentally. The observation provides experimental confirmation of the theoretical model proposed by Zhi-Jie Tan et al. [Phys. Lett. A 268 (2000) 112]. Most strikingly, a transition from a disordered ramified pattern to an ordered pattern (chain-like growth) has been observed. The growth is governed by diffusion, convection and migration in an electric field which give rise to the different patterns. This Letter can also be considered as an experimental evidence of computer simulated fractal growth given by Huang and Hibbert [Physica A 233 (1996) 888].

  4. 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.

  5. Kaon properties in dense nuclear matter: are there experimental evidences of in medio effects?

    SciTech Connect

    Mangiarotti, A.

    2009-06-03

    Beyond the general interest for nuclear matter theory, the K{sup -} in medio mass modification could have important astrophysical consequences. Experimental evidences of how a nuclear medium affects K{sup +} and K{sup -} properties will be summarised. To reach a firm conclusion about the K{sup -}, the missing information on the flow will be shown to be still relevant.

  6. 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 India to…

  7. Teacher Incentives in Developing Countries: Recent Experimental Evidence from Kenya. Working Paper 2008-09

    ERIC Educational Resources Information Center

    Glewwe, Paul; Ilias, Nauman; Kremer, Michael

    2008-01-01

    This paper reviews recent evidence on the impact of a teacher incentives program in Kenya. The results are based on a randomized trial, which removes many sources of bias that can arise in analyses of non-experimental data. One hundred schools in a rural area were randomly divided into 50 that participated in a teacher incentives program and 50…

  8. Teacher Incentives in Developing Countries: Experimental Evidence from Kenya. 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 Kenya"--a paper presented at the National Center on Performance Incentives research to policy conference in February--Paul Glewwe (University of Minnesota), Nauman Illias (The Brattle Group), and Michael Kremer (Harvard University) review findings from recent research in…

  9. An experimental investigation of compressor stall using an on-line distortion indicator and signal conditioner

    NASA Technical Reports Server (NTRS)

    Costakis, W. G.; Wenzel, L. M.

    1975-01-01

    The relation of the steady-state and dynamic distortions and the stall margin of a J85-13 turbojet engine was investigated. A distortion indicator capable of computing two distortion indices was used. A special purpose signal conditioner was also used as an interface between transducer signals and distortion indicator. A good correlation of steady-state distortion and stall margin was established. The prediction of stall by using the indices as instantaneous distortion indicators was not successful. A sensitivity factor that related the loss of stall margin to the turbulence level was found.

  10. Interannual to millennial variability of climate extreme indices over Europe: evidence from high resolution proxy data

    NASA Astrophysics Data System (ADS)

    Rimbu, Norel; Ionita, Monica; Lohmann, Gerrit

    2016-04-01

    Interannual to millennial time scale variability of precipitation (R20mm, Rx5day, R95pTOT), cold (TN10p, CSDI and CFD), heat (TX90p and WSDI) and drought (CDD) extreme climate indices is investigated using long-term observational and proxy records. We detect significant correlations between these indices and various high resolution proxy records like lake sediments from southern Germany, stable oxygen isotopes from Greenland ice cores and stable oxygen isotopes from Red Sea corals during observational period. The analysis of long-term reanalysis data in combination with extreme climate indices and proxy data reveals that distinct atmospheric circulation patterns explain most of the identified relationships. In particular, we show that a sediment record from southern Germany (lake Ammersee), which records flood frequency of River Ammer during the last 5500 years, is related to a wave-train atmospheric circulation pattern with a pronounced negative center over western Europe. We show that high frequency of River Ammer floods is related not only to high frequency of extreme precipitation events (R95p) in the Ammer region but also with significant positive anomalies of various extreme temperature indices (TX90p and TXx) over northeastern Europe. Such extreme temperatures are forced by cloudiness anomaly pattern associated with flood related atmospheric circulation pattern. Based on this record we discuss possible interannual to millennial scale variations of extreme precipitation and temperature indices over Europe during the last 5500 years. Coherent variations of extreme precipitation and temperature indices over Europe and stable oxygen isotopes from Greenland ice cores and northern Red Sea corals during observational period are related to atmospheric blocking variability in the North Atlantic region. Possible variations of climate extreme indices during different time slices of the Holocene period and their implications for future extreme climate variability are

  11. Searching for evidence of changes in extreme rainfall indices in the Central Rift Valley of Ethiopia

    NASA Astrophysics Data System (ADS)

    Muluneh, Alemayehu; Bewket, Woldeamlak; Keesstra, Saskia; Stroosnijder, Leo

    2016-02-01

    Extreme rainfall events have serious implications for economic sectors with a close link to climate such as agriculture and food security. This holds true in the Central Rift Valley (CRV) of Ethiopia where communities rely on highly climate-sensitive rainfed subsistence farming for livelihoods. This study investigates changes in ten extreme rainfall indices over a period of 40 years (1970-2009) using 14 meteorological stations located in the CRV. The CRV consists of three landscape units: the valley floor, the escarpments, and the highlands all of which are considered in our data analysis. The Belg (March-May) and Kiremt (June-September) seasons are also considered in the analysis. The Mann-Kendall test was used to detect trends of the rainfall indices. The results indicated that at the annual time scale, more than half (57 %) of the stations showed significant trends in total wet-day precipitation (PRCPTOT) and heavy precipitation days (R10mm). Only 7-35 % of stations showed significant trends, for the other rainfall indices. Spatially, the valley floor received increasing annual rainfall while the escarpments and the highlands received decreasing annual rainfall over the last 40 years. During Belg, 50 % of the stations showed significant increases in the maximum number of consecutive dry days (CDD) in all parts of the CRV. However, most other rainfall indices during Belg showed no significant changes. During Kiremt, considering both significant and non-significant trends, almost all rainfall indices showed an increasing trend in the valley floor and a decreasing trend in the escarpment and highlands. During Belg and Kiremt, the CDD generally showed increasing tendency in the CRV.

  12. Multiple Sources of Evidence: An Analysis of Stakeholders' Perceptions of Various Indicators of Student Learning

    ERIC Educational Resources Information Center

    Guskey, Thomas R.

    2007-01-01

    This study compared different stakeholders' perceived validity of various indicators of student learning used to judge the quality of students' academic performance. Data were gathered from the questionnaire responses of 314 educators in three states that have implemented comprehensive state-wide assessment programs with high-stakes consequences…

  13. Evidence-Based Practice: Quality Indicator Analysis of Antecedent Exercise in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Kasner, Melanie; Reid, Greg; MacDonald, Cathy

    2012-01-01

    The purpose of the research was to conduct a quality indicator analysis of studies exploring the effects of antecedent exercise on self-stimulatory behaviors of individuals with autism spectrum disorders (ASD). Educational Resources Information Center (ERIC), Google Scholar, SPORTDiscus, PsychINFO, and PubMed/MedLine databases from 1980 to October…

  14. Experimental evidence for the K-LM radiative Auger effect in medium-mass atoms

    NASA Astrophysics Data System (ADS)

    Herren, Ch.; Dousse, J.-Cl.

    1997-10-01

    High-resolution measurements of the Kα1,2 low-energy satellites were performed for the elements 42Mo, 44Ru, 46Pd, 48Cd, and 50Sn. The photoinduced x-ray spectra were measured using a high-resolution transmission-type bent-crystal spectrometer in modified DuMond slit geometry. Experimental evidence for the K-LM radiative Auger effect (RAE) in solid medium-mass atoms was found and particular groups of the K-LM RAE transitions were identified. The experimental intensity ratios I(K-LM RAE) / I(Kα1,2) as well as the relative intensity of the K-L3M4,5 transition group were extracted from the measured spectra. A comparison of the experimental results with relativistic Hartree-Fock theoretical predictions from Scofield shows a good agreement. The experimental energies of the K-LM RAE edges are compared with calculated Auger transition energies.

  15. Experimental evidence of the superfocusing effect for axially channeled MeV protons

    NASA Astrophysics Data System (ADS)

    Motapothula, M.; Petrović, S.; Nešković, N.; Breese, M. B. H.

    2016-08-01

    Sub-Ångström focusing of megaelectronvolt (MeV) ions within axial channels was predicted over 10 years ago, but evidence proved elusive. We present experimental angular distributions of axially channeled MeV protons in a 55-nm-thick (001) silicon membrane through which multiple scattering is negligible. Fine angular structure is in excellent agreement with Monte Carlo simulations based on three interaction potentials, providing indirect evidence of the existence of the superfocusing effect with flux enhancement of around 800 within a focused beam width of ˜20 pm .

  16. Role of Oxidative Stress in Refractory Epilepsy: Evidence in Patients and Experimental Models

    PubMed Central

    Cardenas-Rodriguez, Noemi; Huerta-Gertrudis, Bernardino; Rivera-Espinosa, Liliana; Montesinos-Correa, Hortencia; Bandala, Cindy; Carmona-Aparicio, Liliana; Coballase-Urrutia, Elvia

    2013-01-01

    Oxidative stress, a state of imbalance in the production of reactive oxygen species and nitrogen, is induced by a wide variety of factors. This biochemical state is associated with systemic diseases, and diseases affecting the central nervous system. Epilepsy is a chronic neurological disorder with refractoriness to drug therapy at about 30%. Currently, experimental evidence supports the involvement of oxidative stress in seizures, in the process of their generation, and in the mechanisms associated with refractoriness to drug therapy. Hence, the aim of this review is to present information in order to facilitate the handling of this evidence and determine the therapeutic impact of the biochemical status for this pathology. PMID:23344052

  17. Development and Validation of the Rappel Indicé-24: Behavioral and Brain Morphological Evidence.

    PubMed

    Park, Soowon; Kim, Inhye; Park, Hyun Gyu; Shin, Seong A; Cho, Youngsung; Youn, Jung-Hae; Kim, Yu Kyeong; Lee, Jun-Young

    2016-05-01

    The primary goals of the present study were to develop and validate the Rappel Indicé 24 (RI-24), a shorter version of the original Rappel Indicé, which includes 48 items (RI-48), and to identify the specific brain regions that were correlated with scores on the RI-24. Using these clinical scales, the present study evaluated 91 elderly Korean participants who were classified into 3 groups: normal control (NC; n = 34), patients with mild cognitive impairment (MCI; n = 29), and patients with Alzheimer disease (AD; n = 28). Of the 91 participants, 77 also underwent magnetic resonance imaging scans. The RI-24 delayed cued recall (DCR) scores significantly differed among the NC, MCI, and AD groups. A receiver-operating characteristic curve analysis revealed that the RI-24 was very sensitive (89%) and specific (91%) for the detection of AD. Furthermore, although the time needed to administer the RI-24 was half that needed for the RI-48, the 24-item version showed a high correlation (r= .85 for the DCR score) with the 48-item version. In terms of brain morphological characteristics, voxel-based morphometry analyses revealed a significant positive correlation between DCR score and gray matter volume in the parahippocampal gyrus (r= .468), which plays a role in cued recall. Taken together, the present findings indicate that the RI-24 is a sensitive and reliable test for the detection of memory impairments in patients with MCI and AD despite its brief administration time. PMID:26956224

  18. Island of Rare Earth Nuclei with Tetrahedral and Octahedral Symmetries: Possible Experimental Evidence

    SciTech Connect

    Dudek, J.; Dubray, N.; Pangon, V.; Dobaczewski, J.; Olbratowski, P.; Schunck, N.

    2006-08-18

    Calculations using realistic mean-field methods suggest the existence of nuclear shapes with tetrahedral T{sub d} and/or octahedral O{sub h} symmetries sometimes at only a few hundreds of keV above the ground states in some rare earth nuclei around {sup 156}Gd and {sup 160}Yb. The underlying single-particle spectra manifest exotic fourfold rather than Kramers's twofold degeneracies. The associated shell gaps are very strong, leading to a new form of shape coexistence in many rare earth nuclei. We present possible experimental evidence of the new symmetries based on the published experimental results--although an unambiguous confirmation will require dedicated experiments.

  19. Evidence of Experimental Vertical Transmission of Emerging Novel ECSA Genotype of Chikungunya Virus in Aedes aegypti

    PubMed Central

    Agarwal, Ankita; Dash, Paban Kumar; Singh, Anil Kumar; Sharma, Shashi; Gopalan, Natarajan; Rao, Putcha Venkata Lakshmana; Parida, Man Mohan; Reiter, Paul

    2014-01-01

    Background Chikungunya virus (CHIKV) has emerged as one of the most important arboviruses of public health significance in the past decade. The virus is mainly maintained through human-mosquito-human cycle. Other routes of transmission and the mechanism of maintenance of the virus in nature are not clearly known. Vertical transmission may be a mechanism of sustaining the virus during inter-epidemic periods. Laboratory experiments were conducted to determine whether Aedes aegypti, a principal vector, is capable of vertically transmitting CHIKV or not. Methodology/Principal Findings Female Ae. aegypti were orally infected with a novel ECSA genotype of CHIKV in the 2nd gonotrophic cycle. On day 10 post infection, a non-infectious blood meal was provided to obtain another cycle of eggs. Larvae and adults developed from the eggs obtained following both infectious and non-infectious blood meal were tested for the presence of CHIKV specific RNA through real time RT-PCR. The results revealed that the larvae and adults developed from eggs derived from the infectious blood meal (2nd gonotrophic cycle) were negative for CHIKV RNA. However, the larvae and adults developed after subsequent non-infectious blood meal (3rd gonotrophic cycle) were positive with minimum filial infection rates of 28.2 (1∶35.5) and 20.2 (1∶49.5) respectively. Conclusion/Significance This study is the first to confirm experimental vertical transmission of emerging novel ECSA genotype of CHIKV in Ae. aegypti from India, indicating the possibilities of occurrence of this phenomenon in nature. This evidence may have important consequence for survival of CHIKV during adverse climatic conditions and inter-epidemic periods. PMID:25080107

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

    SciTech Connect

    Chuang, C.-K.; Chen, W.-J.

    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 on 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.

  1. Experimental Evidence of the Origin of Nanophase Separation in Low Hole-Doped Colossal Magnetoresistant Manganites.

    PubMed

    Cortés-Gil, Raquel; Ruiz-González, M Luisa; González-Merchante, Daniel; Alonso, José M; Hernando, Antonio; Trasobares, Susana; Vallet-Regí, María; Rojo, Juan M; González-Calbet, José M

    2016-01-13

    While being key to understanding their intriguing physical properties, the origin of nanophase separation in manganites and other strongly correlated materials is still unclear. Here, experimental evidence is offered for the origin of the controverted phase separation mechanism in the representative La1-xCaxMnO3 system. For low hole densities, direct evidence of Mn(4+) holes localization around Ca(2+) ions is experimentally provided by means of aberration-corrected scanning transmission electron microscopy combined with electron energy loss spectroscopy. These localized holes give rise to the segregated nanoclusters, within which double exchange hopping between Mn(3+) and Mn(4+) remains restricted, accounting for the insulating character of perovskites with low hole density. This localization is explained in terms of a simple model in which Mn(4+) holes are bound to substitutional divalent Ca(2+) ions. PMID:26683223

  2. QTL Mapping OF PARASITE RESISTANCE INDICATOR traits IN AN EXPERIMENTAL ANGUS POPULATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    QTL for parasite indicator traits in cattle are ideal targets for study of marker assisted selection; however, the phenotypic data and available resource populations were not optimal for reliable QTL identification. Fecal egg count (FEC) values, which are used to measure resistance to nematodes, are...

  3. Evaluation of drought indices via 1 remotely sensed data with hydrological variables: Little river experimental watershed, Georgia U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An intercomparison among standard and remotely sensed drought indices was conducted using streamflow and soil moisture measurements collected in the Little River experimental watershed, Georgia US, during the period from 2000 to 2008. The remotely sensed Evaporative Stress Index (ESI) was identified...

  4. Structural and Functional Evidence Indicates Selective Oxygen Signaling in Caldanaerobacter subterraneus H-NOX.

    PubMed

    Hespen, Charles W; Bruegger, Joel J; Phillips-Piro, Christine M; Marletta, Michael A

    2016-08-19

    Acute and specific sensing of diatomic gas molecules is an essential facet of biological signaling. Heme nitric oxide/oxygen binding (H-NOX) proteins are a family of gas sensors found in diverse classes of bacteria and eukaryotes. The most commonly characterized bacterial H-NOX domains are from facultative anaerobes and are activated through a conformational change caused by formation of a 5-coordinate Fe(II)-NO complex. Members of this H-NOX subfamily do not bind O2 and therefore can selectively ligate NO even under aerobic conditions. In contrast, H-NOX domains encoded by obligate anaerobes do form stable 6-coordinate Fe(II)-O2 complexes by utilizing a conserved H-bonding network in the ligand-binding pocket. The biological function of O2-binding H-NOX domains has not been characterized. In this work, the crystal structures of an O2-binding H-NOX domain from the thermophilic obligate anaerobe Caldanaerobacter subterraneus (Cs H-NOX) in the Fe(II)-NO, Fe(II)-CO, and Fe(II)-unliganded states are reported. The Fe(II)-unliganded structure displays a conformational shift distinct from the NO-, CO-, and previously reported O2-coordinated structures. In orthogonal signaling assays using Cs H-NOX and the H-NOX signaling effector histidine kinase from Vibrio cholerae (Vc HnoK), Cs H-NOX regulates Vc HnoK in an O2-dependent manner and requires the H-bonding network to distinguish O2 from other ligands. The crystal structures of Fe(II) unliganded and NO- and CO-bound Cs H-NOX combined with functional assays herein provide the first evidence that H-NOX proteins from obligate anaerobes can serve as O2 sensors. PMID:27328180

  5. 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.

  6. Determinants of relative and absolute concentration indices: evidence from 26 European countries

    PubMed Central

    2013-01-01

    Introduction The aim of publicly-provided health care is generally not only to produce health, but also to decrease variation in health by socio-economic status. The aim of this study is to measure to what extent this goal has been obtained in various European countries and evaluate the determinants of inequalities within countries, as well as cross-country patterns with regard to different cultural, institutional and social settings. Methods The data utilized in this study provides information on 440,000 individuals in 26 European countries and stem from The European Union Statistics on Income and Living Conditions (EU-SILC) collected in 2007. As measures of income-related inequality in health both the relative concentration indices and the absolute concentration indices are calculated. Further, health inequality in each country is decomposed into individual-level determinants and cross-country comparisons are made to shed light on social and institutional determinants. Results Income-related health inequality favoring the better-off is observed for all the 26 European countries. In terms of within-country determinants inequality is mainly explained by income, age, education, and activity status. However, the degree of inequality and contribution of each determinant to inequality varies considerably between countries. Aggregate bivariate linear regressions show that there is a positive association between health-income inequality in Europe and public expenditure on education. Furthermore, a negative relationship between health-income inequality and income inequality was found when individual employee cash income was used in the health-concentration measurement. Using that same income measure, health-income inequality was found to be higher in the Nordic countries than in other areas, but this result is sensitive to the income measure chosen. Conclusions The findings indicate that institutional determinants partly explain income-related health inequalities across

  7. Library residencies and internships as indicators of success: evidence from three programs.

    PubMed Central

    Lanier, D; Henderson, C L

    1999-01-01

    This paper discusses post-master's degree internships in three very different organizations; the University of Illinois at Chicago, the National Library of Medicine, and the Library of Congress. It discusses the internships using several questions. Do the programs serve as a recruitment strategy? Do the programs develop key competencies needed by the participant or organization? Do the programs develop leaders and managers? Is acceptance into a program an indicator of future career success? A survey was mailed to 520 persons who had completed internships in one of the three programs. There was a 49.8% response rate. Responses to fifty-four questions were tabulated and analyzed for each program and for the total group. The results confirm the value of internships to the career of participants. PMID:10219479

  8. Are Front of Pack Claims Indicators of Nutrition Quality? Evidence from 2 Product Categories.

    PubMed

    Schaefer, Debra; Hooker, Neal H; Stanton, John L

    2016-01-01

    American grocery shoppers face an array of front of pack (FOP) nutrition and health claims when making food selections. Such systems have been categorized as summary or nutrient specific. Either type should help consumers make judgments about the nutrition quality of a product. This research tests if the type or quantity of FOP claims are indeed good indicators of objective nutrition quality. Claim and nutrition information from more than 2200 breakfast cereals and prepared meals launched between 2006 and 2010 were analyzed using binary and multinomial logistic regression models. Results suggest that no type or number of front of pack claims could distinguish "healthy" foods. However, some types and frequencies of FOP claims were significant predictors of higher or lower levels of certain key nutrients. Given the complex and crowded label environment in which these FOP claims reside, one may be concerned that such cues are not closely related to objective measures of nutrition quality. PMID:26641596

  9. The effect of a visual indicator on rate of visual search Evidence for processing control

    NASA Technical Reports Server (NTRS)

    Holmgren, J. E.

    1974-01-01

    Search rates were estimated from response latencies in a visual search task of the type used by Atkinson et al. (1969), in which a subject searches a small set of letters to determine the presence or absence of a predesignated target. Half of the visual displays contained a marker above one of the letters. The marked letter was the only one that had to be checked to determine whether or not the display contained the target. The presence of a marker in a display significantly increased the estimated rate of search, but the data clearly indicated that subjects did not restrict processing to the marked item. Letters in the vicinity of the marker were also processed. These results were interpreted as showing that subjects are able to exercise some degree of control over the search process in this type of task.

  10. Characteristics of efficacy evidence supporting approval of supplemental indications for prescription drugs in United States, 2005-14: systematic review

    PubMed Central

    Wang, Bo

    2015-01-01

    Objective To characterize the types of comparators and endpoints used in efficacy trials for approvals of supplemental indications, compared with the data supporting these drugs’ originally approved indications. Design Systematic review. Setting Publicly accessible data on supplemental indications approved by the US Food and Drug Administration from 2005 to 2014. Main outcome measures Types of comparators (active, placebo, historical, none) and endpoints (clinical outcomes, clinical scales, surrogate) in the efficacy trials for these drugs’ supplemental and original indication approvals. Results The cohort included 295 supplemental indications. Thirty per cent (41/136) of supplemental approvals for new indications were supported by efficacy trials with active comparators, compared with 51% (47/93) of modified use approvals and 11% (7/65) of approvals expanding the patient population (P<0.001), almost all of which related to pediatric patients (61/65; 94%). Trials using clinical outcome endpoints led to approval for 32% (44/137) of supplemental approvals for new indications, 30% (28/93) of modified indication approvals, and 22% (14/65) of expanded population approvals (P=0.29). Orphan drugs had supplemental approvals for 40 non-orphan indications, which were supported by similar proportions of trials using active comparators (28% (11/40) for non-orphan supplemental indications versus 24% (10/42) for original orphan indications; P=0.70) and clinical outcome endpoints (25% (10/40) versus 31% (13/42); P=0.55). Conclusions Wide variations were seen in the evidence supporting approval of supplemental indications, with the fewest active comparators and clinical outcome endpoints used in trials leading to supplemental approvals that expanded the patient population. PMID:26400844

  11. Geomorphic Indicators of Ground Ice on Mars and Evidence for Climate Change

    NASA Astrophysics Data System (ADS)

    Mustard, J. F.

    2003-12-01

    Until recently, indications of the presence of ice in the near surface of Mars, outside the polar caps, has depended upon the interpretation of morphology from imaging data. Early work in this area was based primarily on Viking orbiter images where several large landforms (100s to 1000s of meters in scale) were interpreted to be related to the presence of ice in the regolith or upper crust. These include lineated valley fill, concentric crater fill, softened terrain, and polygons, and are typically found between the latitudes of 30° -60° N and S. Without direct measurements of the presence of water, the interpretations rely on analogies with Earth's periglacial and glacial morphologies as well as geophysical modeling of ice-rich soils and crustal material. New spacecraft data from the Mars Global Surveyor and Mars Odyssey missions have significantly added to the family of morphologies with ground-ice affinities. From the high spatial resolution images acquired by Mars Orbiter Camera (MOC) a new array of polygons have been detected which range in size from 25-200 m and show strong latitudinal gradients above 50° . A possibly related morphology exhibiting a regularly spaced surface texture resembling the texture of a basketball is also found in these high latitudes. A number of morphologies indicating viscous flow on steep slopes are found in the mid-latitudes and are consistent with an ice-rich soils deforming under martian surface conditions. A continuous deposit, meters-thick and interpreted to be ice rich is observed at latitudes above 60° , but that is in a degraded condition at lower latitudes (formerly ice-rich) and absent in the equatorial regions (within 30° ). The neutron spectrometer on the Odyssey spacecraft made direct measurements of hydrogen which shows clearly the presence of high water-ice abundance (>70% by volume) in the surface soils in the northern and southern latitudes above 60° . This critical observation ties in well with theoretical

  12. 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. PMID:25904671

  13. 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

  14. Evidence for a bimodal distribution of hybrid indices in a hybrid zone with high admixture

    PubMed Central

    McKenzie, Jessica L.; Dhillon, Rashpal S.; Schulte, Patricia M.

    2015-01-01

    The genetic structure of a hybrid zone can provide insights into the relative roles of the various factors that maintain the zone. Here, we use a multilocus approach to characterize a hybrid zone between two subspecies of killifish (Fundulus heteroclitus, Walbaum 1792) found along the Atlantic coast of North America. We first analysed clinal variation along the Atlantic coast using a single-nucleotide polymorphism in the mitochondrial DNA (mtDNA) displacement loop (D-loop) and a panel of nine nuclear microsatellite markers. A model constraining all clines to the same width and centre was not significantly different from a model in which the clines were allowed to vary independently. Locus-by-locus analysis indicated that the majority of nuclear clines shared the same centre as the mtDNA cline, and the widths of these clines were also narrower than that predicted by a neutral model, suggesting that selection is operating to maintain the hybrid zone. However, two of the nuclear clines had widths greater than the neutral prediction and had centres that were displaced relative to the mtDNA cline centre. We also found that a marsh located near the centre of the mtDNA cline demonstrated a bimodal distribution of nuclear hybrid index values, suggesting a deficit of first-generation hybrids and backcrossed genotypes. Thus, selection against hybrid genotypes may be playing a role in maintaining this hybrid zone and the associated steep nuclear and mtDNA clines. PMID:27019720

  15. Mineralogical Indicators for Climate Change on Mars: Evidence from Landed Missions

    NASA Technical Reports Server (NTRS)

    Ming, D. W.; Morris, R. V.; Clark, B. C.

    2015-01-01

    Mineralogical and geochemical data returned by a flotilla of Mars orbiters and landers over the past 10 years has substantially enhanced our understanding on the evolution of the atmosphere and climate. Instruments onboard Mars Express and MRO discovered widespread deposits of phyllosilicates that formed during the Noachian followed by formation of sulfates into the Hesperian. The formation of extensive valley networks along with these layered deposits of phyllosilicates and sulfates during the late Noachian/ early Hesperian indicate a past martian climate that was capable of maintaining liquid water at the surface. The planet's climate changed substantially after these early 'episodes' of water and very little aqueous alteration has occurred over the past 3.5 Gyrs . A key to understanding Mars past climate is to identify, characterize, and age date secondary minerals that have formed by reaction with volatile compounds, e.g., H2O, CO2, SO2. Here, we summarize the detection of secondary minerals at the four landing sites visited over the past 10 years. We also provide potential pathways for their formation and implications for past climate change on Mars.

  16. Evidence for a bimodal distribution of hybrid indices in a hybrid zone with high admixture.

    PubMed

    McKenzie, Jessica L; Dhillon, Rashpal S; Schulte, Patricia M

    2015-12-01

    The genetic structure of a hybrid zone can provide insights into the relative roles of the various factors that maintain the zone. Here, we use a multilocus approach to characterize a hybrid zone between two subspecies of killifish (Fundulus heteroclitus, Walbaum 1792) found along the Atlantic coast of North America. We first analysed clinal variation along the Atlantic coast using a single-nucleotide polymorphism in the mitochondrial DNA (mtDNA) displacement loop (D-loop) and a panel of nine nuclear microsatellite markers. A model constraining all clines to the same width and centre was not significantly different from a model in which the clines were allowed to vary independently. Locus-by-locus analysis indicated that the majority of nuclear clines shared the same centre as the mtDNA cline, and the widths of these clines were also narrower than that predicted by a neutral model, suggesting that selection is operating to maintain the hybrid zone. However, two of the nuclear clines had widths greater than the neutral prediction and had centres that were displaced relative to the mtDNA cline centre. We also found that a marsh located near the centre of the mtDNA cline demonstrated a bimodal distribution of nuclear hybrid index values, suggesting a deficit of first-generation hybrids and backcrossed genotypes. Thus, selection against hybrid genotypes may be playing a role in maintaining this hybrid zone and the associated steep nuclear and mtDNA clines. PMID:27019720

  17. Induced Cannibalism in Experimental Populations of the Forensic Indicator Chrysomya putoria Wiedemann (Diptera: Calliphoridae).

    PubMed

    Botteon, V W; Fernandes, F S; Godoy, W A C

    2016-04-01

    We analyzed the behavior of third-instars of Chrysomya putoria as potential cannibals in experimental populations. Cannibalism rates were evaluated in three settings observed for 3, 6, 9, and 24 h, placing injured and uninjured larvae of C. putoria together. Our data heavily support that C. putoria larvae behave as cannibals when induced by a wound in another larva, and also after starving for 24 h. The probability of cannibalism increased as a function of time, both in no-choice and in choice experiments evidencing that time is a determining factor for cannibalism induction in C. putoria. However, the treatment combining injured with uninjured larvae showed the highest probability of cannibalism. These results suggest that C. putoria larvae may cannibalize under scarcity of food over long time or the presence of injured larvae. This study is useful to understand the behavior of C. putoria feeding on ephemeral substrates such as carrion or corpses and brings relevant and significant contribution to population ecology of blowflies and also forensic entomology. PMID:26698866

  18. 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…

  19. 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...

  20. [Botulinum toxin type A in headache treatment : Established and experimental indications].

    PubMed

    Gaul, C; Holle-Lee, D; Straube, A

    2016-08-01

    In recent years botulinum toxin type A has been used increasingly more in the treatment of specific headache disorders. Especially regarding chronic migraine with and without combined medication overuse, convincing randomized studies have proven the efficacy of this treatment option and have led to approval for this indication. Regarding other headache entities, such as episodic migraine, tension-type headache, trigeminal autonomic cephalalgia (TAC), neuralgic, neuropathic and myofascial pain, currently available scientific data on the efficacy of botulinum toxin type A are scarce and often ambiguous. The exact underlying mechanisms of the influence of botulinum toxin type A on the pathophysiology of headache are not completely clear but an influence on the release of calcitonin gene-related peptide (CGRP) seems to play a crucial role. This article summarizes the most important studies as well as experiences of treatment with botulinum toxin type A regarding different headache entities. PMID:27300190

  1. Prediction of oral absorption in humans by experimental immobilized artificial membrane chromatography indices and physicochemical descriptors.

    PubMed

    Kotecha, Jignesh; Shah, Shailesh; Rathod, Ishwarsinh; Subbaiah, Gunta

    2008-08-01

    The purpose of the present study was to examine the human oral absorption (HOA) predictability of the experimentally determined immobilized artificial membrane (IAM) chromatography capacity factor (log k'IAM) in conjunction with physicochemical descriptors. Transcellular permeation was modeled based on determination of log k'IAM considering pH partition hypothesis, and the independent variables were polar surface area (PSA) and molecular weight (MW). The correlation between log k'IAM determined at different pH and n-octanol/water partition coefficient (log P) and contribution of polarity (PSA) and size (MW) in the transcellular permeation model were the extension to the previous work. A data set of 37 compounds with partition coefficient values taken from the literature was employed to show importance of ionic interaction in oral absorption prediction. The highest log k'IAM value among screened pH 4.5, 5.5, 6.5 and 7.4 (log k'IAM4.5-7.4) in conjunction with PSA predicted HOA with coefficient of determination (CD) of 0.9001 compare to log k'IAM4.5-7.4 alone with CD of 0.8454 after excluding bretylium from the set of 28 structurally diverse drugs for known reason. PSA helped to avoid over estimation of HOA for amiloride, famotidine and furosemide. The model was tested for its applicability in drug development program and found to predict oral absorption using physically meaningful and structurally related properties making them relatively straightforward for a medicinal chemist to interpret. PMID:18524510

  2. Experimental Infection of Rhodnius prolixus (Hemiptera, Triatominae) with Mycobacterium leprae Indicates Potential for Leprosy Transmission

    PubMed Central

    Neumann, Arthur da Silva; Dias, Felipe de Almeida; Ferreira, Jéssica da Silva; Fontes, Amanda Nogueira Brum; Rosa, Patricia Sammarco; Macedo, Rafael Enrique; Oliveira, José Henrique; Teixeira, Raquel Lima de Figueiredo; Pessolani, Maria Cristina Vidal; Moraes, Milton Ozório; Suffys, Philip Noel; Oliveira, Pedro L.; Sorgine, Marcos Henrique Ferreira; Lara, Flavio Alves

    2016-01-01

    Leprosy is a chronic dermato-neurological disease caused by infection with Mycobacterium leprae. In 2013 almost 200,000 new cases of leprosy were detected around the world. Since the first symptoms take from years to decades to appear, the total number of asymptomatic patients is impossible to predict. Although leprosy is one of the oldest records of human disease, the mechanisms involved with its transmission and epidemiology are still not completely understood. In the present work, we experimentally investigated the hypothesis that the mosquitoes Aedes aegypti and Culex quinquefasciatus and the hemiptera Rhodnius prolixus act as leprosy vectors. By means of real-time PCR quantification of M. leprae 16SrRNA, we found that M. leprae remained viable inside the digestive tract of Rhodnius prolixus for 20 days after oral infection. In contrast, in the gut of both mosquito species tested, we were not able to detect M. leprae RNA after a similar period of time. Inside the kissing bug Rhodnius prolixus digestive tract, M. leprae was initially restricted to the anterior midgut, but gradually moved towards the hindgut, in a time course reminiscent of the life cycle of Trypanosoma cruzi, a well-known pathogen transmitted by this insect. The maintenance of M. leprae infectivity inside the digestive tract of this kissing bug is further supported by successful mice footpad inoculation with feces collected 20 days after infection. We conclude that Rhodnius prolixus defecate infective M. leprae, justifying the evaluation of the presence of M. leprae among sylvatic and domestic kissing bugs in countries endemic for leprosy. PMID:27203082

  3. Predicting antitrichomonal activity: a computational screening using atom-based bilinear indices and experimental proofs.

    PubMed

    Marrero-Ponce, Yovani; Meneses-Marcel, Alfredo; Castillo-Garit, Juan A; Machado-Tugores, Yanetsy; Escario, José Antonio; Barrio, Alicia Gómez; Pereira, David Montero; Nogal-Ruiz, Juan José; Arán, Vicente J; Martínez-Fernández, Antonio R; Torrens, Francisco; Rotondo, Richard; Ibarra-Velarde, Froylán; Alvarado, Ysaias J

    2006-10-01

    Existing Trichomonas vaginalis therapies are out of reach for most trichomoniasis people in developing countries and, where available, they are limited by their toxicity (mainly in pregnant women) and their cost. New antitrichomonal agents are needed to combat emerging metronidazole-resistant trichomoniasis and reduce the side effects associated with currently available drugs. Toward this end, atom-based bilinear indices, a new TOMOCOMD-CARDD molecular descriptor, and linear discriminant analysis (LDA) were used to discover novel, potent, and non-toxic lead trichomonacidal chemicals. Two discriminant functions were obtained with the use of non-stochastic and stochastic atom-type bilinear indices for heteroatoms and H-bonding of heteroatoms. These atomic-level molecular descriptors were calculated using a weighting scheme that includes four atomic labels, namely atomic masses, van der Waals volumes, atomic polarizabilities, and atomic electronegativities in Pauling scale. The obtained LDA-based QSAR models, using non-stochastic and stochastic indices, were able to classify correctly 94.51% (90.63%) and 93.41% (93.75%) of the chemicals in training (test) sets, respectively. They showed large Matthews' correlation coefficients (C); 0.89 (0.79) and 0.87 (0.85), for the training (test) sets, correspondingly. The result of predictions on the 15% full-out cross-validation test also evidenced the robustness and predictive power of the obtained models. In addition, canonical regression analyses corroborated the statistical quality of these models (R(can) of 0.749 and of 0.845, correspondingly); they were also used to compute biological activity canonical scores for each compound. On the other hand, a close inspection of the molecular descriptors included in both equations showed that several of these molecular fingerprints are strongly interrelated with each other. Therefore, these models were orthogonalized using the Randić orthogonalization procedure. These

  4. Experimental evidence of cut-wire-induced enhanced transmission of transverse-electric fields through sub-wavelength slits in a thin metallic screen

    NASA Astrophysics Data System (ADS)

    di Gennaro, Emiliano; Gallina, Ilaria; Andreone, Antonello; Castaldi, Giuseppe; Galdi, Vincenzo

    2010-12-01

    Recent numerical studies have demonstrated the possibility of achieving substantial enhancements in the transmission of transverse-electric-polarized electromagnetic fields through subwavelength slits in a thin metallic screen by placing single or paired metallic cut-wire arrays at a close distance from the screen. In this Letter, we report on the first experimental evidence of such extraordinary transmission phenomena, via microwave (X/Ku-band) measurements on printed-circuit-board prototypes. Experimental results agree very well with full-wave numerical predictions, and indicate an intrinsic robustness of the enhanced transmission phenomena with respect to fabrication tolerances and experimental imperfections.

  5. Sudden Cardiac Risk Stratification with Electrocardiographic Indices - A Review on Computational Processing, Technology Transfer, and Scientific Evidence.

    PubMed

    Gimeno-Blanes, Francisco J; Blanco-Velasco, Manuel; Barquero-Pérez, Óscar; García-Alberola, Arcadi; Rojo-Álvarez, José L

    2016-01-01

    Great effort has been devoted in recent years to the development of sudden cardiac risk predictors as a function of electric cardiac signals, mainly obtained from the electrocardiogram (ECG) analysis. But these prediction techniques are still seldom used in clinical practice, partly due to its limited diagnostic accuracy and to the lack of consensus about the appropriate computational signal processing implementation. This paper addresses a three-fold approach, based on ECG indices, to structure this review on sudden cardiac risk stratification. First, throughout the computational techniques that had been widely proposed for obtaining these indices in technical literature. Second, over the scientific evidence, that although is supported by observational clinical studies, they are not always representative enough. And third, via the limited technology transfer of academy-accepted algorithms, requiring further meditation for future systems. We focus on three families of ECG derived indices which are tackled from the aforementioned viewpoints, namely, heart rate turbulence (HRT), heart rate variability (HRV), and T-wave alternans. In terms of computational algorithms, we still need clearer scientific evidence, standardizing, and benchmarking, siting on advanced algorithms applied over large and representative datasets. New scenarios like electronic health recordings, big data, long-term monitoring, and cloud databases, will eventually open new frameworks to foresee suitable new paradigms in the near future. PMID:27014083

  6. Sudden Cardiac Risk Stratification with Electrocardiographic Indices - A Review on Computational Processing, Technology Transfer, and Scientific Evidence

    PubMed Central

    Gimeno-Blanes, Francisco J.; Blanco-Velasco, Manuel; Barquero-Pérez, Óscar; García-Alberola, Arcadi; Rojo-Álvarez, José L.

    2016-01-01

    Great effort has been devoted in recent years to the development of sudden cardiac risk predictors as a function of electric cardiac signals, mainly obtained from the electrocardiogram (ECG) analysis. But these prediction techniques are still seldom used in clinical practice, partly due to its limited diagnostic accuracy and to the lack of consensus about the appropriate computational signal processing implementation. This paper addresses a three-fold approach, based on ECG indices, to structure this review on sudden cardiac risk stratification. First, throughout the computational techniques that had been widely proposed for obtaining these indices in technical literature. Second, over the scientific evidence, that although is supported by observational clinical studies, they are not always representative enough. And third, via the limited technology transfer of academy-accepted algorithms, requiring further meditation for future systems. We focus on three families of ECG derived indices which are tackled from the aforementioned viewpoints, namely, heart rate turbulence (HRT), heart rate variability (HRV), and T-wave alternans. In terms of computational algorithms, we still need clearer scientific evidence, standardizing, and benchmarking, siting on advanced algorithms applied over large and representative datasets. New scenarios like electronic health recordings, big data, long-term monitoring, and cloud databases, will eventually open new frameworks to foresee suitable new paradigms in the near future. PMID:27014083

  7. Experimental evidence for the acceleration of thermal electrons by ion cyclotron waves in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Norris, A. J.; Sojka, J. J.; Wrenn, G. L.; Johnson, J. F. E.; Cornilleau-Wehrlin, N.; Perraut, S.; Roux, A.

    1983-01-01

    Experimental evidence is presented for the acceleration of thermal electrons by large amplitude ion cyclotron waves (ICWs). The wave power in the ULF range near the helium gyrofrequency is compared with the distribution function of low energy electrons measured by GEOS satellite instruments. This comparison shows that electrons are accelerated near the geomagnetic equator along field lines, at times when the ICW energy is large and the cold plasma density is below a threshold value. It is suggested that these accelerated electrons can account for the ELF emissions, modulated at the ICW frequency, observed by Wehrlin (1981). A very efficient acceleration of thermal electrons along field lines results from other ULF events having frequencies close to the proton gyrofrequency. Evidence for this lies in the fact that medium energy protons having large temperature anisotropies in the 100-500 eV range are responsible for the ICW wave generation.

  8. Experimental evidence for the stability of the depletion zone around a growing protein crystal under microgravity.

    PubMed

    Otálora, F; Novella, M L; Gavira, J A; Thomas, B R; García Ruiz, J M

    2001-03-01

    Experimental evidence is presented for the first time for the development and time evolution of concentration-depletion zones around protein crystals growing in microgravity and gelled on-ground experiments. Crystal motion and buoyancy-driven fluid movements as a result of residual accelerations and g-jitters are demonstrated to have an adverse effect on the stability of these depletion zones, provoking the breakdown of their radial symmetry. These findings may explain some of the controversial results reported on the quality of single crystals grown under microgravity in previous space missions. PMID:11223518

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

    SciTech Connect

    Roul, Basanta; Kumar, Mahesh; Rajpalke, Mohana K.; Bhat, Thirumaleshwara N.; Krupanidhi, S. B.; Kalghatgi, A. T.; Kumar, Nitesh; Sundaresan, A.

    2011-10-17

    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.

  10. Experimental evidence for chirality in the odd-A 105Rh

    NASA Astrophysics Data System (ADS)

    Timár, J.; Joshi, P.; Starosta, K.; Dimitrov, V. I.; Fossan, D. B.; Molnár, J.; Sohler, D.; Wadsworth, R.; Algora, A.; Bednarczyk, P.; Curien, D.; Dombrádi, Zs.; Duchene, G.; Gizon, A.; Gizon, J.; Jenkins, D. G.; Koike, T.; Krasznahorkay, A.; Paul, E. S.; Raddon, P. M.; Rainovski, G.; Scheurer, J. N.; Simons, A. J.; Vaman, C.; Wilkinson, A. R.; Zolnai, L.; Frauendorf, S.

    2004-09-01

    High-spin states in 105Rh were populated by the 96Zr(13C, p3n) reaction at beam energies of 51 and 58 MeV, and studied using the EUROBALL IV γ-ray spectrometer and the DIAMANT charged particle array. A pair of nearly degenerate ΔI = 1 three-quasiparticle bands with the same spins and parity have been observed. Comparison of the experimental results with tilted axis cranking calculations confirms the chiral character of the two bands, while arguments based on the excitation of particles within the πg9 / 2 ν(h11 / 2) 2 configuration of the yrast band and comparison with the previously observed γ band exclude the other possible interpretations. This is the first experimental evidence for three-quasiparticle chiral structure in the A ∼ 100 region, and the first simultaneous observation of a γ band and chiral partner bands in one nucleus.

  11. Evidence of Experimental Bias in the Life Sciences: Why We Need Blind Data Recording.

    PubMed

    Holman, Luke; Head, Megan L; Lanfear, Robert; Jennions, Michael D

    2015-07-01

    Observer bias and other "experimenter effects" occur when researchers' expectations influence study outcome. These biases are strongest when researchers expect a particular result, are measuring subjective variables, and have an incentive to produce data that confirm predictions. To minimize bias, it is good practice to work "blind," meaning that experimenters are unaware of the identity or treatment group of their subjects while conducting research. Here, using text mining and a literature review, we find evidence that blind protocols are uncommon in the life sciences and that nonblind studies tend to report higher effect sizes and more significant p-values. We discuss methods to minimize bias and urge researchers, editors, and peer reviewers to keep blind protocols in mind. PMID:26154287

  12. Experimental evidence of deterministic coherence resonance in coupled chaotic systems with frequency mismatch

    NASA Astrophysics Data System (ADS)

    García-Vellisca, M. A.; Pisarchik, A. N.; Jaimes-Reátegui, R.

    2016-07-01

    We present the experimental evidence of deterministic coherence resonance in unidirectionally coupled two and three Rössler electronic oscillators with mismatch between their natural frequencies. The regularity in both the amplitude and the phase of chaotic fluctuations is experimentally proven by the analyses of normalized standard deviations of the peak amplitude and interpeak interval and Lyapunov exponents. The resonant chaos suppression appears when the coupling strength is increased and the oscillators are in phase synchronization. In two coupled oscillators, the coherence enhancement is associated with negative third and fourth Lyapunov exponents, while the largest first and second exponents remain positive. Distinctly, in three oscillators coupled in a ring, all exponents become negative, giving rise to periodicity. Numerical simulations are in good agreement with the experiments.

  13. Experimental and theoretical evidence for an ionic crystal of ammonia at high pressure

    NASA Astrophysics Data System (ADS)

    Ninet, S.; Datchi, F.; Dumas, P.; Mezouar, M.; Garbarino, G.; Mafety, A.; Pickard, C. J.; Needs, R. J.; Saitta, A. M.

    2014-05-01

    We report experimental and theoretical evidence that solid molecular ammonia becomes unstable at room temperature and high pressures and transforms into an ionic crystalline form. This material has been characterized in both hydrogenated (NH3) and deuterated (ND3) ammonia samples up to about 180 and 200 GPa, respectively, by infrared absorption, Raman spectroscopy, and x-ray diffraction. The presence of a new strong infrared absorption band centered at 2500 cm-1 in NH3 (1900 cm-1 in ND3) is in line with previous theoretical predictions regarding the ionization of ammonia molecules into NH2- and NH4+ ions. The experimental data suggest the coexistence of two crystalline ionic forms, which our ab initio structure searches predict to be the most stable at the relevant pressures. The ionic crystalline form of ammonia appears stable at low temperatures, which contrasts with the behavior of water in which no equivalent crystalline ionic phase has been found.

  14. Evidence of Experimental Bias in the Life Sciences: Why We Need Blind Data Recording

    PubMed Central

    Lanfear, Robert; Jennions, Michael D.

    2015-01-01

    Observer bias and other “experimenter effects” occur when researchers’ expectations influence study outcome. These biases are strongest when researchers expect a particular result, are measuring subjective variables, and have an incentive to produce data that confirm predictions. To minimize bias, it is good practice to work “blind,” meaning that experimenters are unaware of the identity or treatment group of their subjects while conducting research. Here, using text mining and a literature review, we find evidence that blind protocols are uncommon in the life sciences and that nonblind studies tend to report higher effect sizes and more significant p-values. We discuss methods to minimize bias and urge researchers, editors, and peer reviewers to keep blind protocols in mind. PMID:26154287

  15. Experimental evidence of high-frequency complete elastic bandgap in pillar-based phononic slabs

    SciTech Connect

    Pourabolghasem, Reza; Mohammadi, Saeed; Eftekhar, Ali A.; Adibi, Ali; Khelif, Abdelkrim

    2014-12-08

    We present strong experimental evidence for the existence of a complete phononic bandgap, for Lamb waves, in the high frequency regime (i.e., 800 MHz) for a pillar-based phononic crystal (PnC) membrane with a triangular lattice of gold pillars on top. The membrane is composed of an aluminum nitride film stacked on thin molybdenum and silicon layers. Experimental characterization shows a large attenuation of at least 20 dB in the three major crystallographic directions of the PnC lattice in the frequency range of 760 MHz–820 MHz, which is in agreement with our finite element simulations of the PnC bandgap. The results of experiments are analyzed and the physics behind the attenuation in different spectral windows is explained methodically by assessing the type of Bloch modes and the in-plane symmetry of the displacement profile.

  16. 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. PMID:26809142

  17. 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. PMID:27009222

  18. Experimental evidence that brighter males sire more extra-pair young in tree swallows.

    PubMed

    Whittingham, Linda A; Dunn, Peter O

    2016-08-01

    Across taxa, extra-pair mating is widespread among socially monogamous species, but few studies have identified male ornamental traits associated with extra-pair mating success, and even fewer studies have experimentally manipulated male traits to determine whether they are related directly to paternity. As a consequence, there is little experimental evidence to support the widespread hypothesis that females choose more ornamented males as extra-pair mates. Here, we conducted an experimental study of the relationship between male plumage colour and fertilization success in tree swallows (Tachycineta bicolor), which have one of the highest levels of extra-pair mating in birds. In this study, we experimentally dulled the bright blue plumage on the back of males (with nontoxic ink markers) early in the breeding season prior to most mating. Compared with control males, dulled males sired fewer extra-pair young, and, as a result, fewer young overall. Among untreated males, brighter blue males also sired more extra-pair young, and in paired comparisons, extra-pair sires had brighter blue plumage than the within-pair male they cuckolded. These results, together with previous work on tree swallows, suggest that extra-pair mating behaviour is driven by benefits to both males and females. PMID:27105297

  19. 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. PMID:25479506

  20. Delayed school start times and adolescent sleep: A systematic review of the experimental evidence.

    PubMed

    Minges, Karl E; Redeker, Nancy S

    2016-08-01

    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 25-60 min, and correspondingly, total sleep time increased from 25 to 77 min 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

  1. Experimental Evidence Linking Elevated CO2, Rhizosphere C/N Stoichiometry and Microbial Efficiency

    NASA Astrophysics Data System (ADS)

    Carrillo, Y.; Dijkstra, F. A.; Pendall, E.; LeCain, D. R.; Morgan, J.

    2012-12-01

    expected to be more efficient in their C use. Decreasing the C/N ratio of roots decreased SOM respiration and increased the efficiency of SOM-consuming microbes. Direct N additions had a similar but stronger effect. Increased C efficiency with greater nutrient availability is consistent with theoretical expectations of C utilization under nutrient limitation. Notably, the response of C use to N treatments occurred only under eCO2 conditions. This functional contrast was supported by differential responses of microbial PLFA profiles to N treatments under CO2 treatments. Together, these results suggest that the eCO2 environment was more conducive to N limitation, via changes in microbial community structure and function. Our results provide direct experimental evidence of plant-mediated alteration of decomposer C efficiency due to changes in atmospheric CO2 and N availability from both plant and soil sources. An increase in SOM-consuming microbes efficiency in an eCO2 world is likely to have important ecosystem-level implications as it could enhance the amount of C that remains in soil relative to the amount released to the atmosphere. The interactive effects of CO2 and N treatments suggest that microbial efficiency will be more sensitive to changes in nutrient status under the future eCO2 atmosphere.

  2. Exploring the limitations of pathophysiological indicators used for targeted selective treatment in sheep experimentally infected with Haemonchus contortus.

    PubMed

    Chylinski, C; Cortet, J; Neveu, C; Cabaret, J

    2015-01-15

    Identifying which sheep to treat as part of a Targeted Selective Treatment approach to gastro-intestinal nematode control relies entirely on the efficacy of the indicators. Indicators such as FAMACHA© (anaemia), DISCO (diarrhea) and reductions in weight gains were designed specifically to reflect those sheep experiencing symptomatic consequences of infection. Using the gastro-intestinal nematode Haemonchus contortus as a model species, this study explored the utility and sensitivity of these indicators under controlled experimental conditions on 63 adult sheep. The potential effect of sheep with different H. contortus resistance phenotypes on indicator efficacy was compared in three different phenotypes, i.e. high (Blackbelly females), medium (Blackbelly rams) and low resistance (Romane rams). The potential effect of the H. contortus isolate on indicator efficacy was also explored by using four different isolates, with varying anthelmintic resistance capacities, to infect the sheep. We limited the study to the first month of infection to evaluate the interest of these indicators as an early predictive means for controlling infection. The pathophysiological indicators FAMACHA© and DISCO do not reflect infection intensity based on Faecal Egg Counts, nor do reductions in weight gains. FAMACHA© was however a good indicator of anaemia with strong correlations to haematocrit. There was little agreement among the three indicators to identify the same animals in need of treatment and even combining them did not increase their predictive value of infection intensity or relative host damage from infection. The indicator sensitivity was influenced by the H. contortus isolate and sheep resistance phenotype in which they were tested. One isolate was poorly infective but induced high levels of anaemia (FAMACHA©) and diarrhea (DISCO) compared to the three others. The FAMACHA© and DISCO had higher values in the sheep group with a medium resistance phenotype (Blackbelly rams

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

    PubMed

    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

  4. 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.

  5. 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

  6. Experimental evidence for state-dependent nest weight in the blue tit, Cyanistes caeruleus.

    PubMed

    Mainwaring, Mark C; Hartley, Ian R

    2009-05-01

    Parental investment in reproduction is generally limited by food availability, and so avian life-history research has traditionally focused on the brood rearing phase, when food requirements are greatest. Only relatively recently has the focus extended to the incubation phase, and even more recently to the nest-building phase, where observational and comparative evidence suggest that avian nest building is an energetically expensive and time-consuming activity. We aimed to experimentally test the limitations on this cost in a hole-breeding passerine, the blue tit (Cyanistes caeruleus), by providing supplementary food to experimental pairs during the nest-building period. In comparison with control females, that did not receive supplementary food, experimental females constructed heavier nests, with greater amounts of moss base but similar amounts of cup lining, despite there being no differences in the time taken to build the nest. This study provides empirical support for the hypothesis that avian nest building is a costly behaviour, limited by food availability. PMID:19429209

  7. 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

  8. 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. PMID:26501958

  9. A multidisciplinary weight of evidence approach for environmental risk assessment at the Costa Concordia wreck: Integrative indices from Mussel Watch.

    PubMed

    Regoli, Francesco; Pellegrini, David; Cicero, Anna Maria; Nigro, Marco; Benedetti, Maura; Gorbi, Stefania; Fattorini, Daniele; D'Errico, Giuseppe; Di Carlo, Marta; Nardi, Alessandro; Gaion, Andrea; Scuderi, Alice; Giuliani, Silvia; Romanelli, Giulia; Berto, Daniela; Trabucco, Benedetta; Guidi, Patrizia; Bernardeschi, Margherita; Scarcelli, Vittoria; Frenzilli, Giada

    2014-05-01

    A complex framework of chemical, biological and oceanographic activities was immediately activated after the Costa Concordia shipwreck, to assess possible contamination events and the environmental impact during both emergency and wreck removal operations. In the present paper, we describe the results obtained with caged mussels, Mytilus galloprovincialis, chosen as bioindicator organisms to detect variations of bioavailability and the early onset of molecular and cellular effects (biomarkers). Seven translocation experiments were carried out during the first year from the incident, with organisms deployed at 2 depths in 3 different sites. After 4-6 weeks, tissue concentrations were measured for the main classes of potentially released chemicals (trace metals, polycyclic aromatic hydrocarbons, volatile and aliphatic hydrocarbons, polychlorinated biphenyls, halogenated pesticides, organotin compounds, brominated flame retardants, anionic surfactants); a wide battery of biomarkers covered responses indicative of exposure, detoxification, oxidative stress, cell damage and genotoxic effects. Results excluded serious contamination events or a consistent increase of environmental pollution although some episodic spills with reversible effects were detected. Data were elaborated within a quantitative weight of evidence (WOE) model which provided synthetic hazard indices for each typology of data, before their overall integration in an environmental risk index, which generally ranged from slight to moderate. The proposed WOE model was confirmed a useful tool to summarize large datasets of complex data in integrative indices, and to simplify the interpretation for stakeholders and decision makers, thus supporting a more comprehensive process of "site-oriented" management decisions. PMID:24144855

  10. Geomorphic evidence for former lobate debris aprons at low latitudes on Mars: Indicators of the Martian paleoclimate

    USGS Publications Warehouse

    Hauber, E.; Van Gasselt, S.; Chapman, M.G.; Neukum, G.

    2008-01-01

    Circumferential depressions enclosing mesas and plateaus in the northern Kasei Valles and in the Tartarus Colles regions of Mars are interpreted as indicators of the former extent of lobate debris aprons, thought to be mixtures of ice and elastic particles. These former lobate debris aprons existed about 1 Ga ago and were embayed by lavas or other flow deposits. After the lobate debris aprons had been removed by sublimation and deflation, topographic depressions with a depth of 50 m and a width of several kilometers were left behind between the mesa or plateau scarp and the solidified flow materials. These depressions or moats are located equatorward of ??30?? at significantly lower latitudes than generally observed for occurrences of modem, intact lobate debris aprons. This observation provides evidence that the paleoclimate at that time was different than today, probably due to a higher averaged obliquity of the planet's rotational axis. Copyright 2008 by the American Geophysical Union.

  11. 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

  12. Universal limiting shape of worn profile under multiple-mode fretting conditions: theory and experimental evidence

    PubMed Central

    Dmitriev, Andrey I.; Voll, Lars B.; Psakhie, Sergey G.; Popov, Valentin L.

    2016-01-01

    We consider multiple-mode fretting wear in a frictional contact of elastic bodies subjected to a small-amplitude oscillation, which may include in-plane and out-of-plane translation, torsion and tilting (“periodic rolling”). While the detailed kinetics of wear depends on the particular loading history and wear mechanism, the final worn shape, under some additional conditions, occurs to be universal for all types and loading and wear mechanisms. This universal form is determined solely by the radius of the permanent stick region and the maximum indentation depth during the loading cycle. We provide experimental evidence for the correctness of the theoretically predicted limiting shape. The existence of the universal limiting shape can be used for designing joints which are resistant to fretting wear. PMID:26979092

  13. Universal limiting shape of worn profile under multiple-mode fretting conditions: theory and experimental evidence.

    PubMed

    Dmitriev, Andrey I; Voll, Lars B; Psakhie, Sergey G; Popov, Valentin L

    2016-01-01

    We consider multiple-mode fretting wear in a frictional contact of elastic bodies subjected to a small-amplitude oscillation, which may include in-plane and out-of-plane translation, torsion and tilting ("periodic rolling"). While the detailed kinetics of wear depends on the particular loading history and wear mechanism, the final worn shape, under some additional conditions, occurs to be universal for all types and loading and wear mechanisms. This universal form is determined solely by the radius of the permanent stick region and the maximum indentation depth during the loading cycle. We provide experimental evidence for the correctness of the theoretically predicted limiting shape. The existence of the universal limiting shape can be used for designing joints which are resistant to fretting wear. PMID:26979092

  14. 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.

  15. 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

    2014-09-01

    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.

  16. 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. PMID:26699455

  17. First experimental evidence of the feasibility of multi-color magnetic particle imaging

    NASA Astrophysics Data System (ADS)

    Rahmer, J.; Halkola, A.; Gleich, B.; Schmale, I.; Borgert, J.

    2015-03-01

    Magnetic particle imaging is a new approach to visualizing magnetic nanoparticles. It is capable of 3D real-time in vivo imaging of particles injected into the blood stream and is a candidate for medical imaging applications. To date, only one particle type has been imaged at a time, however, the ability to separate signals acquired simultaneously from different particle types or from particles in different environments would substantially increase the scope of the method. Different colors could be assigned to different signal sources to allow for visualization in a single image. Successful signal separation has been reported in spectroscopic experiments, but it was unclear how well separation would work in conjunction with spatial encoding in an imaging experiment. This work presents experimental evidence of the separability of signals from different particle types and aggregation states (fluid versus powder) using a ‘multi-color’ reconstruction approach. Several mechanisms are discussed that may form the basis for successful signal separation.

  18. Effect of insulin-induced hypoglycaemia on the central nervous system: evidence from experimental studies.

    PubMed

    Jensen, V F H; Bøgh, I B; Lykkesfeldt, J

    2014-03-01

    Insulin-induced hypoglycaemia (IIH) is a major acute complication in type 1 as well as in type 2 diabetes, particularly during intensive insulin therapy. The brain plays a central role in the counter-regulatory response by eliciting parasympathetic and sympathetic hormone responses to restore normoglycaemia. Brain glucose concentrations, being approximately 15-20% of the blood glucose concentration in humans, are rigorously maintained during hypoglycaemia through adaptions such as increased cerebral glucose transport, decreased cerebral glucose utilisation and, possibly, by using central nervous system glycogen as a glucose reserve. However, during sustained hypoglycaemia, the brain cannot maintain a sufficient glucose influx and, as the cerebral hypoglycaemia becomes severe, electroencephalogram changes, oxidative stress and regional neuronal death ensues. With particular focus on evidence from experimental studies on nondiabetic IIH, this review outlines the central mechanisms behind the counter-regulatory response to IIH, as well as cerebral adaption to avoid sequelae of cerebral neuroglycopaenia, including seizures and coma. PMID:24428753

  19. Hypertension and Dementia: Epidemiological and Experimental Evidence Revealing a Detrimental Relationship.

    PubMed

    Perrotta, Marialuisa; Lembo, Giuseppe; Carnevale, Daniela

    2016-01-01

    Hypertension and dementia represent two major public health challenges worldwide, notably in the elderly population. Although these two conditions have classically been recognized as two distinct diseases, mounting epidemiological, clinical and experimental evidence suggest that hypertension and dementia are strictly intertwined. Here, we briefly report how hypertension profoundly affects brain homeostasis, both at the structural and functional level. Chronic high blood pressure modifies the cerebral vasculature, increasing the risk of Aβ clearance impairment. The latter, excluding genetic etiologies, is considered one of the main causes of Aβ deposition in the brain. Studies have shown that hypertension induces cerebral arterial stiffening and microvascular dysfunction, thus contributing to dementia pathophysiology. This review examines the existing and the updated literature which has attempted to explain and clarify the relationship between hypertension and dementia at the pathophysiological level. PMID:27005613

  20. Hypertension and Dementia: Epidemiological and Experimental Evidence Revealing a Detrimental Relationship

    PubMed Central

    Perrotta, Marialuisa; Lembo, Giuseppe; Carnevale, Daniela

    2016-01-01

    Hypertension and dementia represent two major public health challenges worldwide, notably in the elderly population. Although these two conditions have classically been recognized as two distinct diseases, mounting epidemiological, clinical and experimental evidence suggest that hypertension and dementia are strictly intertwined. Here, we briefly report how hypertension profoundly affects brain homeostasis, both at the structural and functional level. Chronic high blood pressure modifies the cerebral vasculature, increasing the risk of Aβ clearance impairment. The latter, excluding genetic etiologies, is considered one of the main causes of Aβ deposition in the brain. Studies have shown that hypertension induces cerebral arterial stiffening and microvascular dysfunction, thus contributing to dementia pathophysiology. This review examines the existing and the updated literature which has attempted to explain and clarify the relationship between hypertension and dementia at the pathophysiological level. PMID:27005613

  1. Experimental evidence for alleviating nociceptive hypersensitivity by single application of capsaicin.

    PubMed

    Ma, Xiao-Li; Zhang, Fang-Xiong; Dong, Fei; Bao, Lan; Zhang, Xu

    2015-01-01

    The single application of high-concentration of capsaicin has been used as an analgesic therapy of persistent pain. However, its effectiveness and underlying mechanisms remain to be further evaluated with experimental approaches. The present study provided evidence showing that the single application of capsaicin dose-dependently alleviated nociceptive hypersensitivity, and reduced the action potential firing in small-diameter neurons of the dorsal root ganglia (DRG) in rats and mice. Pre-treatment with capsaicin reduced formalin-induced acute nocifensive behavior after a brief hyperalgesia in rats and mice. The inhibitory effects of capsaicin were calcium-dependent, and mediated by the capsaicin receptor (transient receptor potential vanilloid type-1). We further found that capsaicin exerted inhibitory effects on the persistent nociceptive hypersensitivity induced by peripheral inflammation and nerve injury. Thus, these results support the long-lasting and inhibitory effects of topical capsaicin on persistent pain, and the clinic use of capsaicin as a pain therapy. PMID:25896608

  2. 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. PMID:25267469

  3. Universal limiting shape of worn profile under multiple-mode fretting conditions: theory and experimental evidence

    NASA Astrophysics Data System (ADS)

    Dmitriev, Andrey I.; Voll, Lars B.; Psakhie, Sergey G.; Popov, Valentin L.

    2016-03-01

    We consider multiple-mode fretting wear in a frictional contact of elastic bodies subjected to a small-amplitude oscillation, which may include in-plane and out-of-plane translation, torsion and tilting (“periodic rolling”). While the detailed kinetics of wear depends on the particular loading history and wear mechanism, the final worn shape, under some additional conditions, occurs to be universal for all types and loading and wear mechanisms. This universal form is determined solely by the radius of the permanent stick region and the maximum indentation depth during the loading cycle. We provide experimental evidence for the correctness of the theoretically predicted limiting shape. The existence of the universal limiting shape can be used for designing joints which are resistant to fretting wear.

  4. 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

  5. Developmental neurotoxicity of ortho-phthalate diesters: review of human and experimental evidence.

    PubMed

    Miodovnik, Amir; Edwards, Andrea; Bellinger, David C; Hauser, Russ

    2014-03-01

    Ortho-phthalate diesters, or phthalates, are widely used synthetic chemicals found primarily in consumer products and polyvinyl chloride plastics. Experimental evidence suggests that several phthalates possess antiandrogenic properties and may disrupt endocrine pathways resulting in abnormal reproductive outcomes. Low-level exposure to phthalates has been well documented in humans, with higher levels found in children and women of childbearing age. Recent epidemiologic studies postulate that prenatal exposure to measurable urine phthalate concentrations may be associated with altered genital and pubertal development in infants and children. This review addresses the emerging evidence that some phthalates may have an adverse impact on the developing brain. The supporting animal studies and proposed mechanisms underlying the deleterious properties of phthalates in relation to neurodevelopmental outcomes are also discussed. While the observed associations are based on limited studies with a broad range of endpoints, the implications of such outcomes are of concern from a public health standpoint and merit further investigation given the widespread nature of the exposure. PMID:24486776

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

    PubMed

    Riesch, Rüdiger; Plath, Martin; Schlupp, Ingo

    2011-12-23

    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

  7. Which is the best indicator of muscle oxygen extraction during exercise using NIRS?: Evidence that HHb is not the candidate.

    PubMed

    Kime, Ryotaro; Fujioka, Masako; Osawa, Takuya; Takagi, Shun; Niwayama, Masatsugu; Kaneko, Yasuhisa; Osada, Takuya; Murase, Norio; Katsumura, Toshihito

    2013-01-01

    Recently, deoxygenated hemoglobin (HHb) has been used as one of the most popular indicators of muscle O2 extraction during exercise in the field of exercise physiology. However, HHb may not sufficiently represent muscle O2 extraction, as total hemoglobin (tHb) is not stable during exercise. The purpose of this study was to measure various muscle oxygenation signals during cycle exercise and clarify which is the best indicator of muscle O2 extraction during exercise using NIRS. Ten healthy men performed 6-min cycle exercise at both moderate and heavy work rates. Oxygenated hemoglobin (O2-Hb), HHb, tHb, and muscle tissue oxygen saturation (SmO2) were measured with near-infrared spatial resolved spectroscopy from the vastus lateralis muscle. Skin blood flow (sBF) was also monitored at a site close to the NIRS probe. During moderate exercise, tHb, O2-Hb, and SmO2 displayed progressive increases until the end of exercise. In contrast, HHb remained stable during moderate work rate. sBF remained stable during moderate exercise but showed a progressive decrease at heavy work rate. These results provide evidence that HHb may not sufficiently represent muscle O2 extraction since tHb is not stable during exercise and HHb is insensitive to exercise-induced hyperaemia. PMID:23852491

  8. 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. PMID:27470424

  9. Lightning injury as a blast injury of skull, brain, and visceral lesions: clinical and experimental evidences.

    PubMed

    Ohashi, M; Hosoda, Y; Fujishiro, Y; Tuyuki, A; Kikuchi, K; Obara, H; Kitagawa, N; Ishikawa, T

    2001-12-01

    The present study attempts to better understand the mechanism of injuries associated with direct lightning strikes. We reviewed the records of 256 individuals struck by lightning between 1965 and 1999, including 56 people who were killed. Basal skull fracture, intracranial haemorrhage, pulmonary haemorrhage, or solid organ rupture was suspected in three men who died. Generally these lesions have been attributed to current flow or falling after being struck. However, examination of surface injuries sustained suggested that the true cause was concussion secondary to blast injury resulting from vaporization of water on the body surface by a surface flashover spark. To investigate this hypothesis, an experimental model of a lightning strike was created in the rat. Saline-soaked blotting paper was used to simulate wet clothing or skin, and an artificial lightning impulse was applied. The resultant lesions were consistent with our hypothesis that the blast was reinforced by the concussive effect of water vaporization. The concordance between the clinical and experimental evidence argues strongly for blast injury as an important source of morbidity and mortality in lightning strikes. PMID:11806503

  10. 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.

  11. Genetic and experimental evidence for cross-species infection by swine hepatitis E virus.

    PubMed

    Meng, X J; Halbur, P G; Shapiro, M S; Govindarajan, S; Bruna, J D; Mushahwar, I K; Purcell, R H; Emerson, S U

    1998-12-01

    Prior to the recent discovery of the swine hepatitis E virus (swine HEV) in pigs from the midwestern United States, HEV was not considered endemic to this country. Since swine HEV is antigenically and genetically related to human strains of HEV, it was important to characterize this new virus further. The infectivity titer of a pool of swine HEV in pigs was determined in order to prepare a standardized reagent and to evaluate the dose response in pigs. Although the sequence of swine HEV varied extensively from those of most human strains of HEV, it was very closely related to the two strains of human HEV (US-1 and US-2) isolated in the United States. The U.S. strains which were recently recovered from two patients with clinical hepatitis E in the United States shared >/=97% amino acid identity with swine HEV in open reading frames 1 and 2. Phylogenetic analyses of different regions of the genome revealed that swine HEV and the U.S. strains grouped together and formed a distinct branch. These results suggested that swine HEV may infect humans. When we inoculated rhesus monkeys and a chimpanzee, experimental surrogates of humans, with swine HEV, the primates became infected. Furthermore, in a reciprocal experiment, specific-pathogen-free pigs were experimentally infected with the US-2 strain of human HEV that is genetically similar to swine HEV. These results provided experimental evidence for cross-species infection by the swine virus. Thus, humans appear to be at risk of infection with swine HEV or closely related viruses. PMID:9811705

  12. Impact of SOL plasma profiles on lower hybrid current drive: Experimental evidence, mitigation and modeling approaches

    NASA Astrophysics Data System (ADS)

    Shiraiwa, S.; Baek, S. G.; Faust, I.; Wallace, G.; Bonoli, P.; Meneghini, O.; Mumgaard, R.; Parker, R.; Scott, S.; Harvey, R. W.; Ding, B. J.; Li, M. H.; Lin, S. Y.; Yang, C.

    2015-12-01

    Recent progress in understanding and mitigating parasitic wave absorption in edge plasmas is presented. Experimental observations collected on Alcator C-Mod suggest multiple physics mechanisms are involved in such losses. Localized measurement of parametric decay instabilities (PDIs) has been performed using RF Langmuir probes. The divertor heat flux due to LH and ionization power loss have been evaluated quantitatively. We observe that the LHCD efficiency can be recovered when the SOL density profile is controlled by operating the tokamak at high current. The experimental progresses motivated a re-examination of the LHCD simulation model based on the ray-tracing/Fokker-Planck code (GENRAY/CQL3D). The effect of introducing a relatively small wave number broadening in the launched power spectrum and using 2D SOL density and temperature profiles was investigated. Comparison with C-Mod experiment indicates that the new model can explain the experimental trend over a wider density range including the density regime where disagreement was seen previously, suggesting that including realistic SOL geometry is a key to improve the simulation accuracy.

  13. 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.

  14. Can people really "laugh at themselves?"--experimental and correlational evidence.

    PubMed

    Beermann, Ursula; Ruch, Willibald

    2011-06-01

    Laughing at oneself is considered a core component of the sense of humor in the theories of several authors. In McGhee's (1996) eight-step-training program of the sense of humor, laughing at oneself constitutes one of the most difficult levels. However, until now, only little empirical evidence on laughing at oneself exists. Using a multimethod approach, in the current study, 70 psychology students and a total of 126 peers filled in the Sense of Humor Scale (SHS, McGhee, 1996), containing as a subscale "Laughing at oneself". In addition, the participants answered the Trait and State forms of the State-Trait-Cheerfulness-Inventory (STCI, Ruch, Köhler, & van Thriel, 1996; Ruch, Köhler, & van Thriel, 1997). They then were confronted with six distorted images of themselves. Facial responses of the participants were videotaped and analyzed using the Facial Action Coding System (FACS, Ekman, Friesen, & Hager, 2002). Four indicators of exhilaration were examined: (a) experienced funniness, (b) AU12 smiles, (c) Duchenne displays, and (d) laughter. Furthermore, fake and masking smiles were studied. Results demonstrated that self- and peer reports of "laughing at oneself" converged moderately. All four indicators of exhilaration were shown, but funniness and laughter seemed to be the most strongly related indicators. Trait cheerfulness and (low) seriousness, and a cheerful mood state formed further characteristics of persons who laugh at themselves. PMID:21668102

  15. 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. PMID:26543577

  16. Experimental evidence for convergent evolution of maternal care heuristics in industrialized and small-scale populations

    PubMed Central

    Kushnick, Geoff; Hanowell, Ben; Kim, Jun-Hong; Langstieh, Banrida; Magnano, Vittorio; Oláh, Katalin

    2015-01-01

    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. PMID:26543577

  17. The Impact of Smoking Bans on Smoking and Consumer Behavior: Quasi-Experimental Evidence from Switzerland.

    PubMed

    Boes, Stefan; Marti, Joachim; Maclean, Johanna Catherine

    2015-11-01

    In this paper, we exploit the progressive implementation of smoking bans in public venues at the state level in Switzerland to evaluate both the direct effects on smoking and the potential unintended consequences of these legislations on consumer behaviors as measured by visiting restaurants/bars and discos ('going out'). Our results indicate that public venue smoking bans in Switzerland reduce smoking rates, but the findings do not emerge until 1 year following the ban. This pattern of results is consistent with delays in ban enforcement on the part of business owners, difficulties in changing addictive behaviors such as smoking, and/or learning on the part of smokers. We find evidence that smoking bans influence going-out behavior and there is substantial heterogeneity across venue and consumer characteristics. PMID:25251559

  18. Experimental Evidence of melt-brake at seismic rates in sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Kuo, L.; Suppe, J.; Song, S.; Song, Y.; Yeh, E.; Dong, J.; Wang, C.; Yang, C.

    2011-12-01

    Frictional melts generated along seismic faults theoretically may act either as a lubricant or as a viscous brake. Present geological and geophysical evidence supports melt-lubrication, which is also in good agreement with extreme strength weakening in laboratory frictional experiments. On the contrary, the strengthening behavior of viscous melts at seismic rates is not well reported, especially in sedimentary rocks. Here we provide laboratory evidence of progressive increase in frictional resistance on sandstone at a slip rate of 1.3 m/s with melt generation. The produced melt/pseudotachylyte is observed with Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and is in-situ analyzed with X-ray diffraction analysis (XRD) and Transmission X-ray Microscopy (TXM) in synchrotron radiation. These analytical results show that the formation of pseudotachylyte is composed of pulverized quartz grains suspending in amorphous melts from thermally decomposed clay minerals. The observation of TXM also indicates that the shapes of quartz grains in the slip zone vary from rounded in the central area to angular on the rim. In-situ microstructures and high frictional resistance of sandstones in experiments indicate that the dominant strengthening mechanism is possibly controlled by viscous melts with suspending quartz grains. The melt rheology at high slip rates is not well understood, but the frictional behavior of melt with nano-sized quartz grains appears to be rheopetic instead of melt lubrication and/or powder lubrication. Thus, it suggests that the first-time rupture of sedimentary faults is not lubricated by melts during earthquake; in contrast melts from thermally decomposed clay minerals with suspending quartz grains produced by faulting may be an important process for the dynamic strengthening of faults.

  19. First experimental evidence for female mate choice in a nocturnal primate.

    PubMed

    Craul, Mathias; Zimmermann, Elke; Radespiel, Ute

    2004-10-01

    Female mate choice can be hypothesised in most nocturnal primates, since females show a higher investment in their offspring than males. The aim of this experimental study was to investigate if female grey mouse lemurs perform mate choice and whether age, relatedness (to the male), or male advertisement call activity systematically influence their decisions. A two-way mate choice design was developed in which females could choose between two males. Mate choice was deduced from the time spent in proximity to the males and from mating behaviour. During oestrus 12 of 17 females participated actively in the experiment and all of them showed either a significant spatial (n = 11) or behavioural (n = 1) preference for one male. In four cases copulations were observed. The influence of age on female mate choice was not statistically significant. In the cases with copulations, however, females mostly preferred the older male. This might indicate a preference for older age as an indicator of experience, fitness, and/or status. The influence of relatedness on female mate choice could not be definitely clarified. However, results imply a mechanism of kin recognition on the basis of familiarity. In the majority of choices, females preferred the male with higher trill call activity. Since trill call activity correlates with the relative dominance status of males, these results suggest an importance of the male dominance status for female mate choice in grey mouse lemurs. Altogether our findings indicate that females use a complex of different cues to choose their mates. PMID:15241637

  20. The benefits of synchronous collaborative information visualization: evidence from an experimental evaluation.

    PubMed

    Bresciani, Sabrina; Eppler, Martin J

    2009-01-01

    A great corpus of studies reports empirical evidence of how information visualization supports comprehension and analysis of data. The benefits of visualization for synchronous group knowledge work, however, have not been addressed extensively. Anecdotal evidence and use cases illustrate the benefits of synchronous collaborative information visualization, but very few empirical studies have rigorously examined the impact of visualization on group knowledge work. We have consequently designed and conducted an experiment in which we have analyzed the impact of visualization on knowledge sharing in situated work groups. Our experimental study consists of evaluating the performance of 131 subjects (all experienced managers) in groups of 5 (for a total of 26 groups), working together on a real-life knowledge sharing task. We compare (1) the control condition (no visualization provided), with two visualization supports: (2) optimal and (3) suboptimal visualization (based on a previous survey). The facilitator of each group was asked to populate the provided interactive visual template with insights from the group, and to organize the contributions according to the group consensus. We have evaluated the results through both objective and subjective measures. Our statistical analysis clearly shows that interactive visualization has a statistically significant, objective and positive impact on the outcomes of knowledge sharing, but that the subjects seem not to be aware of this. In particular, groups supported by visualization achieved higher productivity, higher quality of outcome and greater knowledge gains. No statistically significant results could be found between an optimal and a suboptimal visualization though (as classified by the pre-experiment survey). Subjects also did not seem to be aware of the benefits that the visualizations provided as no difference between the visualization and the control conditions was found for the self-reported measures of satisfaction

  1. Experimental evidence of transport of pesticides through field soils - a review

    SciTech Connect

    Flury, M.

    1996-01-01

    Much information is available in the literature about pesticide transport through soils at the field scale. The purpose of this study is to review the literature with a focus on pesticide leaching to groundwater. The literature was compiled and discussed with respect to different factors that influence pesticide leaching. Pesticide leaching below the root zone has been demonstrated in sandy as well as in loamy soils. Particularly in loamy soils, there is evidence that even strongly adsorbing chemicals can move along preferential flow pathways and that the travel times of pesticides are comparable to those of conservative solutes. The amounts of pesticides leached below the root zone by worst case rainfall events depend on the chemical properties and can reach up to 5% of the applied mass. When there is no heavy rainfall shortly following application of chemicals, the mass annually leached below the root zone is in the range of <0.1 to 1%, occasionally it can reach up to 4%. Although a direct comparison cannot be made, the mass lost by leaching seems generally to be smaller than that lost by runoff, depending of course on the slope of the fields. Several factors that affect pesticide leaching, such as surface preparation, soil structure, soil water content, type of irrigation, pesticide formulation, time of application and rainfall events, are discussed with support of experimental evidence. While some factors showed inconsistent effects, others show promise in controlling leaching mechanisms. These latter factors include initial water content, surface preparation, and time of pesticide application. Based on the reviewed literature recommendations were made for future research activities. 172 refs., 1 fig., 7 tabs.

  2. High Pressure Experimental Studies on CuO: Indication of Re-entrant Multiferroicity at Room Temperature

    PubMed Central

    Jana, Rajesh; Saha, Pinku; Pareek, Vivek; Basu, Abhisek; Kapri, Sutanu; Bhattacharyya, Sayan; Mukherjee, Goutam Dev

    2016-01-01

    We have carried out detailed experimental investigations on polycrystalline CuO using dielectric constant, dc resistance, Raman spectroscopy and X-ray diffraction measurements at high pressures. Observation of anomalous changes both in dielectric constant and dielectric loss in the pressure range 3.7–4.4 GPa and reversal of piezoelectric current with reversal of poling field direction indicate to a change in ferroelectric order in CuO at high pressures. A sudden jump in Raman integrated intensity of Ag mode at 3.4 GPa and observation of Curie-Weiss type behaviour in dielectric constant below 3.7 GPa lends credibility to above ferroelectric transition. A slope change in the linear behaviour of the Ag mode and a minimum in the FWHM of the same indicate indirectly to a change in magnetic ordering. Since all the previous studies show a strong spin-lattice interaction in CuO, observed change in ferroic behaviour at high pressures can be related to a reentrant multiferroic ordering in the range 3.4 to 4.4 GPa, much earlier than predicted by theoretical studies. We argue that enhancement of spin frustration due to anisotropic compression that leads to change in internal lattice strain brings the multiferroic ordering to room temperature at high pressures. PMID:27530329

  3. High Pressure Experimental Studies on CuO: Indication of Re-entrant Multiferroicity at Room Temperature.

    PubMed

    Jana, Rajesh; Saha, Pinku; Pareek, Vivek; Basu, Abhisek; Kapri, Sutanu; Bhattacharyya, Sayan; Mukherjee, Goutam Dev

    2016-01-01

    We have carried out detailed experimental investigations on polycrystalline CuO using dielectric constant, dc resistance, Raman spectroscopy and X-ray diffraction measurements at high pressures. Observation of anomalous changes both in dielectric constant and dielectric loss in the pressure range 3.7-4.4 GPa and reversal of piezoelectric current with reversal of poling field direction indicate to a change in ferroelectric order in CuO at high pressures. A sudden jump in Raman integrated intensity of Ag mode at 3.4 GPa and observation of Curie-Weiss type behaviour in dielectric constant below 3.7 GPa lends credibility to above ferroelectric transition. A slope change in the linear behaviour of the Ag mode and a minimum in the FWHM of the same indicate indirectly to a change in magnetic ordering. Since all the previous studies show a strong spin-lattice interaction in CuO, observed change in ferroic behaviour at high pressures can be related to a reentrant multiferroic ordering in the range 3.4 to 4.4 GPa, much earlier than predicted by theoretical studies. We argue that enhancement of spin frustration due to anisotropic compression that leads to change in internal lattice strain brings the multiferroic ordering to room temperature at high pressures. PMID:27530329

  4. Dynamic Analysis of Changes of Protein Levels and Selected Biochemical Indices in Rat Serum in the Course of Experimental Pleurisy.

    PubMed

    Całkosiński, Ireneusz; Majda, Jacek; Terlecki, Grzegorz; Gostomska-Pampuch, Kinga; Małolepsza-Jarmołowska, Katarzyna; Sobolewska, Sylwia; Całkosińska, Aleksandra; Kumala, Aleksandra; Gamian, Andrzej

    2016-06-01

    A significant role is played in inflammation by the liver, which, stimulated by inflammatory mediators, synthetizes plasma proteins with various dynamics. The purpose of these studies is to generate a detailed dynamic analysis of changes to concentrations of plasma and serum protein fractions and selected acute-phase proteins as well as nonspecific biochemical indices during the course of an induced pleurisy. The studies were conducted on female inbred Buffalo rats, which were divided into two groups: a control group (C) and an experimental group (IP) in which pleurisy was induced. In the IP group, significant changes in biochemical indices were observed between the 48th and 96th hours of pleurisy. A reduction of albumin, transferrin, urea, and creatinine concentrations was observed, while concentrations of the complement components C3 and C4, haptoglobin, and fibrinogen increased. An early increase of IL-1 was observed, while increases of IL-6 and TNF were noted in the later period. The maximum intensity of the processes described above occurred between the 72nd and 96th hours of pleurisy. PMID:27083876

  5. 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

  6. Lanthanide humic substances complexation. I. Experimental evidence for a lanthanide contraction effect

    NASA Astrophysics Data System (ADS)

    Sonke, Jeroen E.; Salters, Vincent J. M.

    2006-03-01

    The interaction of the lanthanides (Ln) with humic substances (HS) was investigated with a novel chemical speciation tool, Capillary Electrophoresis-Inductively Coupled Plasma Mass Spectrometry (CE-ICP-MS). By using an EDTA-ligand competition method, a bi-modal species distribution of LnEDTA and LnHS is attained, separated by CE, and detected online by sector field ICP-MS. We quantified the binding of all 14 rare earth elements (REEs), Sc and Y with Suwannee river fulvic acid, Leonardite coal humic acid, and Elliot soil humic acid under environmental conditions (pH 6-9, 0.001-0.1 mol L -1 NaNO 3, 1-1000 nmol L -1 Ln, 10-20 mg L -1 HS). Conditional binding constants for REE-HS interaction ( Kc) ranged from 8.9 < log Kc < 16.5 under all experimental conditions, and display a lanthanide contraction effect, ΔLKc: a gradual increase in Kc from La to Lu by 2-3 orders of magnitude as a function of decreasing ionic radius. HS polyelectrolyte effects cause Kc to increase with increasing pH and decreasing ionic strength. ΔLKc increases significantly with increasing pH, and likely with decreasing ionic strength. Based on a strong correlation between ΔLKc values and denticity for organic acids, we suggest that HS form a range of tri- to tetra-dentate complexes under environmental conditions. These results confirm HS to be a strong complexing agent for Ln, and show rigorous experimental evidence for potential REE fractionation by HS complexation.

  7. 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

  8. Molecular dynamics prediction and experimental evidence for density of normal and metastable liquid zirconium

    NASA Astrophysics Data System (ADS)

    Wang, H. P.; Yang, S. J.; Hu, L.; Wei, B.

    2016-06-01

    The density of normal and metastable undercooled liquid zirconium was predicted by performing molecular dynamics calculation with a system consisting of 4000 atoms and measured by electrostatic levitation experiments. The results show that the density increases linearly with the descending of temperature, including a maximum undercooling of 928 K. The density is 6.00 g cm-3 at the melting temperature, which agrees well with the experimental result of 6.06 g cm-3. Furthermore, the atomic number is increased to 32,000 on the basis of 4000 atoms and there appears only 0.02% difference. Besides, the pair distribution function was applied to display the atomic structure, which indicates the liquid structure change occurs at the first neighbor distance.

  9. EXPERIMENTAL EVIDENCE FOR WATER FORMATION VIA OZONE HYDROGENATION ON DUST GRAINS AT 10 K

    SciTech Connect

    Mokrane, H.; Chaabouni, H.; Accolla, M.; Congiu, E.; Dulieu, F.; Chehrouri, M.; Lemaire, J. L.

    2009-11-10

    The formation of water molecules from the reaction between ozone (O{sub 3}) and D-atoms is studied experimentally for the first time. Ozone is deposited on non-porous amorphous solid water ice (H{sub 2}O), and D-atoms are then sent onto the sample held at 10 K. HDO molecules are detected during the desorption of the whole substrate where isotope mixing takes place, indicating that water synthesis has occurred. The efficiency of water formation via hydrogenation of ozone is of the same order of magnitude as that found for reactions involving O-atoms or O{sub 2} molecules and exhibits no apparent activation barrier. These experiments validate the assumption made by models using ozone as one of the precursors of water formation via solid-state chemistry on interstellar dust grains.

  10. Time-lag in extinction dynamics in experimental populations: evidence for a genetic Allee effect?

    PubMed

    Vercken, Elodie; Vincent, Flora; Mailleret, Ludovic; Ris, Nicolas; Tabone, Elisabeth; Fauvergue, Xavier

    2013-05-01

    1. Propagule pressure, i.e. the number of individuals introduced, is thought to be a major predictor of the establishment success of introduced populations in the field. Its influence in laboratory experimental systems has however been questioned. In fact, other factors involved in long-term population persistence, like habitat size, were usually found to explain most of the dynamics of experimental populations. 2. To better understand the respective influence of short- and long-term factors and their potential interaction on extinction dynamics in experimental systems, we investigated the influence of propagule pressure, habitat size and genetic background on the early dynamics of laboratory-based populations of a hymenopteran parasitoid. 3. The amount of demographic variance differed between establishment and persistence phase and was influenced by habitat size and genetic background (geographic strain), but independent of propagule pressure. In contrast, the probability of extinction within five generations depended on the genetic background and on the interaction between propagule pressure and habitat size. Vulnerability to extinction in small size habitats was increased when populations were founded with a small number of individuals, but this effect was delayed until the third to fifth generations. 4. These results indicate that demographic stochasticity is influential during population establishment, but is not affected by the genetic variability of propagules. On the other hand, extinction might be influenced by a genetic Allee effect triggered by the combination of low propagule pressure and genetic drift. Finally, we documented consistent differences between genetic backgrounds in both deterministic and stochastic population dynamics patterns, with major consequences on extinction risk and ultimately population establishment. PMID:23398653

  11. Theoretical and experimental evidence for the post-cotunnite phase transition in zirconia at high pressure

    NASA Astrophysics Data System (ADS)

    Nishio-Hamane, Daisuke; Dekura, Haruhiko; Seto, Yusuke; Yagi, Takehiko

    2015-05-01

    A post-cotunnite phase transition in zirconia (ZrO2) at high pressure was investigated by synchrotron X-ray diffraction measurements and ab initio calculations based on density functional theory. This study successfully demonstrated a cotunnite- to Fe2P-type phase transition. Static enthalpy difference (Δ H) calculations predicted the appearance of the Fe2P phase at 124 GPa (LDA) and 143 GPa (GGA), and experimental trials demonstrated the coexistence of the Fe2P and cotunnite phases at 175 GPa after heating to 3,000 K. Both phases were quenchable to ambient conditions. The volume of the Fe2P phase was slightly less (~Δ 0.6 %) than that of the cotunnite phase over the experimental pressure range, indicating that the Fe2P phase is the higher pressure phase. The coexistence of both phases in this study may be attributed to the slow kinetics of the phase transition resulting from the close structural relationship of the two phases. An Fe2P-type structural model can be derived by applying a simple operation to the cotunnite-type structure, consisting of a 1/2 shift of several zirconium arrangements parallel to the b-axis of the cotunnite-type unit cell. It is concluded that the high-pressure cotunnite-to-Fe2P phase transition may be a common trend in many dioxides.

  12. 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.

  13. 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.

  14. Experimental Evidence for an Eco-Evolutionary Coupling between Local Adaptation and Intraspecific Competition.

    PubMed

    Siepielski, Adam M; Nemirov, Alex; Cattivera, Matthew; Nickerson, Avery

    2016-04-01

    Determining how adaptive evolution can be coupled to ecological processes is key for developing a more integrative understanding of the demographic factors that regulate populations. Intraspecific competition is an especially important ecological process because it generates negative density dependence in demographic rates. Although ecological factors are most often investigated to determine the strength of density dependence, evolutionary processes such as local adaptation could also feed back to shape variation in the strength of density dependence among populations. Using an experimental approach with damselflies, a predaceous aquatic insect, we find evidence that both density-dependent intraspecific competition and local adaptation can reduce per capita growth rates. In some cases, the effects of local adaptation on reducing per capita growth rates exceeded the ecological competitive effects of a doubling of density. However, we also found that these ecological and evolutionary properties of populations are coupled, and we offer two interpretations of the causes underlying this pattern: (1) the strength of density-dependent competition depends on the extent of local adaptation, or (2) the extent of local adaptation is shaped by the strength of density-dependent competition. Regardless of the underlying causal pathway, these results show how eco-evolutionary dynamics can affect a key demographic process regulating populations. PMID:27028073

  15. Bacteria are not too small for spatial sensing of chemical gradients: An experimental evidence

    PubMed Central

    Thar, Roland; Kühl, Michael

    2003-01-01

    By analyzing the chemotactic behavior of a recently described marine bacterial species, we provide experimental evidence that bacteria are not too small for sensing chemical gradients spatially. The bipolar flagellated vibrioid bacteria (typical size 2 × 6 μm) exhibit a unique motility pattern as they translate along as well as rotate around their short axis, i.e., the pathways of the cell poles describe a double helix. The natural habitat of the bacteria is characterized by steep oxygen gradients where they accumulate in a band at their preferred oxygen concentration of ≈2 μM. Single cells leaving the band toward the oxic region typically return to the band within 16 s following a U-shaped track. A detailed analysis of the tracks reveals that the cells must be able to sense the oxygen gradient perpendicular to their swimming direction. Thus, they can detect oxygen gradients along a distance of ≈5 μm corresponding to the extension of their long axis. The observed behavior can be explained by the presence of two independent sensor regions at either cell pole that modulate the rotation speed of the polar flagellar bundles, i.e., the flagellar bundle at the cell pole exposed to higher oxygen concentration is rotating faster than the other bundle. A mathematical model based on these assumptions reproduces the observed swimming behavior of the bacteria. PMID:12719518

  16. 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.

  17. 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

  18. Experimental evidence of lateral flow in unsaturated homogeneous isotropic sloping soil due to rainfall

    NASA Astrophysics Data System (ADS)

    Sinai, G.; Dirksen, C.

    2006-12-01

    This paper describes laboratory experimental evidence for lateral flow in the top layer of unsaturated sloping soil due to rainfall. Water was applied uniformly on horizontal and V-shaped surfaces of fine sand, at rates about 100 times smaller than the saturated hydraulic conductivity. Flow regimes near the surface and in the soil bulk were studied by using dyes. Streamlines and streak lines and wetting fronts were visually studied and photographed through a vertical glass wall. Near wetting fronts the flow direction was always perpendicular to the fronts owing to dominant matrix potential gradients. Thus, during early wetting of dry sloping sand, the flow direction is directed upslope. Far above a wetting front the flow was vertical due to the dominance of gravity. Downslope flow was observed during decreasing rainfall and dry periods. The lateral movement was largest near the soil surface and decayed with soil depth. Unstable downslope lateral flow close to the soil surface was attributed to non-Darcian flow due to variable temporal and spatial raindrop distributions. The experiments verify the theory that predicts unsaturated downslope lateral flow in sloping soil due to rainfall dynamics only, without apparent soil texture difference or anisotropy. This phenomenon could have significant implications for hillside hydrology, desert agriculture, irrigation management, etc., as well as for the basic mechanisms of surface runoff and erosion.

  19. Proprioceptive Dysfunction in Focal Dystonia: From Experimental Evidence to Rehabilitation Strategies

    PubMed Central

    Avanzino, Laura; Fiorio, Mirta

    2014-01-01

    Dystonia has historically been considered a disorder of the basal ganglia, mainly affecting planning and execution of voluntary movements. This notion comes from the observation that most lesions responsible for secondary dystonia involve the basal ganglia. However, what emerges from recent research is that dystonia is linked to the dysfunction of a complex neural network that comprises basal ganglia–thalamic–frontal cortex, but also the inferior parietal cortex and the cerebellum. While dystonia is clearly a motor problem, it turned out that sensory aspects are also fundamental, especially those related to proprioception. We outline experimental evidence for proprioceptive dysfunction in focal dystonia from intrinsic sensory abnormalities to impaired sensorimotor integration, which is the process by which sensory information is used to plan and execute volitional movements. Particularly, we will focus on proprioceptive aspects of dystonia, including: (i) processing of vibratory input, (ii) temporal discrimination of two passive movements, (iii) multimodal integration of visual-tactile and proprioceptive inputs, and (iv) motor control in the absence of visual feedback. We suggest that these investigations contribute not only to a better understanding of dystonia pathophysiology, but also to develop rehabilitation strategies aimed at facilitating the processing of proprioceptive input. PMID:25538612

  20. First experimental evidence of the feasibility of multi-color magnetic particle imaging.

    PubMed

    Rahmer, J; Halkola, A; Gleich, B; Schmale, I; Borgert, J

    2015-03-01

    Magnetic particle imaging is a new approach to visualizing magnetic nanoparticles. It is capable of 3D real-time in vivo imaging of particles injected into the blood stream and is a candidate for medical imaging applications. To date, only one particle type has been imaged at a time, however, the ability to separate signals acquired simultaneously from different particle types or from particles in different environments would substantially increase the scope of the method. Different colors could be assigned to different signal sources to allow for visualization in a single image. Successful signal separation has been reported in spectroscopic experiments, but it was unclear how well separation would work in conjunction with spatial encoding in an imaging experiment. This work presents experimental evidence of the separability of signals from different particle types and aggregation states (fluid versus powder) using a 'multi-color' reconstruction approach. Several mechanisms are discussed that may form the basis for successful signal separation. PMID:25658130

  1. 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. PMID:23646942

  2. An evidence-update on the prospective relationship between childhood sedentary behaviour and biomedical health indicators: a systematic review and meta-analysis.

    PubMed

    van Ekris, E; Altenburg, T M; Singh, A S; Proper, K I; Heymans, M W; Chinapaw, M J M

    2016-09-01

    Evidence for adverse health effects of excessive sedentary behaviour in children is predominantly based on cross-sectional studies, measuring TV viewing as proxy for sedentary behaviour. This systematic review and meta-analysis summarizes the evidence on the prospective relationship between childhood sedentary behaviour and biomedical health indicators, overall and stratified by type of sedentary behaviour (TV viewing, computer use/games, screen time and objective sedentary time). PubMed, EMBASE, PsycINFO and Cochrane were systematically searched till January 2015. Methodological quality of all included studies was scored, and a best evidence synthesis was applied. We included 109 studies of which 19 were of high quality. We found moderate-to-strong evidence for a relationship of overall sedentary time with some anthropometrics (overweight/obesity, weight-for-height), one cardiometabolic biomarker (HDL-cholesterol) and some fitness indicators (fitness, being unfit). For other health indicators, we found no convincing evidence because of inconsistent or non-significant findings. The evidence varied by type of sedentary behaviour. The meta-analysis indicated that each additional baseline hour of TV viewing (β = 0.01, 95%CI = [-0.002; 0.02]) or computer use (β = 0.00, 95%CI = [-0.004; 0.01]) per day was not significantly related with BMI at follow-up. We conclude that the evidence for a prospective relationship between childhood sedentary behaviour and biomedical health is in general unconvincing. PMID:27256486

  3. 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.

  4. Experimental evidence and isotopomer analysis of mixotrophic glucose metabolism in the marine diatom Phaeodactylum tricornutum

    PubMed Central

    2013-01-01

    Background Heterotrophic fermentation using simple sugars such as glucose is an established and cost-effective method for synthesizing bioproducts from bacteria, yeast and algae. Organisms incapable of metabolizing glucose have limited applications as cell factories, often despite many other advantageous characteristics. Therefore, there is a clear need to investigate glucose metabolism in potential cell factories. One such organism, with a unique metabolic network and a propensity to synthesize highly reduced compounds as a large fraction of its biomass, is the marine diatom Phaeodactylum tricornutum (Pt). Although Pt has been engineered to metabolize glucose, conflicting lines of evidence leave it unresolved whether Pt can natively consume glucose. Results Isotope labeling experiments in which Pt was mixotrophically grown under light on 100% U-13C glucose and naturally abundant (~99% 12C) dissolved inorganic carbon resulted in proteinogenic amino acids with an average 13C-enrichment of 88%, thus providing convincing evidence of glucose uptake and metabolism. The dissolved inorganic carbon was largely incorporated through anaplerotic rather than photosynthetic fixation. Furthermore, an isotope labeling experiment utilizing 1-13C glucose and subsequent metabolic pathway analysis indicated that (i) the alternative Entner-Doudoroff and Phosphoketolase glycolytic pathways are active during glucose metabolism, and (ii) during mixotrophic growth, serine and glycine are largely synthesized from glyoxylate through photorespiratory reactions rather than from 3-phosphoglycerate. We validated the latter result for mixotrophic growth on glycerol by performing a 2-13C glycerol isotope labeling experiment. Additionally, gene expression assays showed that known, native glucose transporters in Pt are largely insensitive to glucose or light, whereas the gene encoding cytosolic fructose bisphosphate aldolase 3, an important glycolytic enzyme, is overexpressed in light but

  5. [Zinc homeostasis and indicators of muscle activity in experimental graduated exercise on the background of zinc asparaginate].

    PubMed

    Skalny, A A; Tinkov, A A; Medvedeva, Yu S; Alchinova, I B; Bonitenko, E Yu; Karganov, M Yu; Nikonorov, A A

    2015-01-01

    The influence of a regular (for 7 and 14 days) 10-minute dosed exercise in isolation and on the background of intragastric administration of 5 and 15 mg/kg of zinc (II) asparaginate on the distribution of this metal in the organs and tissues of experimental animals and the indicators of muscle activity such as the level of lactate, creatinine and creatine kinase (EC 2.7.3.2.) serum were studied. It has been shown that exercise stress for 14 days causes a more pronounced change in homeostasis Zn, compared with 7 day, it is reflected in increased levels in the kidney, serum, liver, skeletal muscle and fur animals. It has been shown that graduated exercise for 14 days causes a more pronounced change in Zn homeostasis, compared with 7 day that expressed in increased its levels in the kidney, serum, liver, skeletal muscle and fur animals. Introduction zinc (II) asparaginate accompanied by an increase of its content in the liver, kidneys, hair and serum, but not skeletal and cardiac muscle. The combination of physical activity and the introduction of zinc positive effect on homeostasis of Zn, and the terms of muscle activity. The protective effect of zinc asparaginate with graduated exercise in the experiment was concluded. PMID:27116879

  6. Experimental Evidence for Self-Limiting Reactive Flow through a Fractured Cement Core: Implications for Time-Dependent Wellbore Leakage

    SciTech Connect

    Huerta, Nicolas J.; Hesse, Marc A.; Bryant, Steven L.; Strazisar, Brian R; Lopano, Christina L.

    2013-01-01

    We present a set of reactive transport experiments in cement fractures. The experiments simulate coupling between flow and reaction when acidic, CO{sub 2}-rich fluids flow along a leaky wellbore. An analog dilute acid with a pH between 2.0 and 3.15 was injected at constant rate between 0.3 and 9.4 cm/s into a fractured cement core. Pressure differential across the core and effluent pH were measured to track flow path evolution, which was analyzed with electron microscopy after injection. In many experiments reaction was restricted within relatively narrow, tortuous channels along the fracture surface. The observations are consistent with coupling between flow and dissolution/precipitation. Injected acid reacts along the fracture surface to leach calcium from cement phases. Ahead of the reaction front, high pH pore fluid mixes with calcium-rich water and induces mineral precipitation. Increases in the pressure differential for most experiments indicate that precipitation can be sufficient to restrict flow. Experimental data from this study combined with published field evidence for mineral precipitation along cemented annuli suggests that leakage of CO{sub 2}-rich fluids along a wellbore may seal the leakage pathway if the initial aperture is small and residence time allows mobilization and precipitation of minerals along the fracture.

  7. Experimental inoculation of Artibeus jamaicensis bats with dengue virus serotypes 1 or 4 showed no evidence of sustained replication.

    PubMed

    Cabrera-Romo, Salomé; Recio-Tótoro, Benito; Alcalá, Ana C; Lanz, Humberto; del Ángel, Rosa María; Sánchez-Cordero, Victor; Rodríguez-Moreno, Ángel; Ludert, Juan E

    2014-12-01

    Dengue is the most important mosquito-borne viral disease to humans. Bats are potential reservoirs for flaviviruses, including dengue virus (DENV). In this work, Artibeus jamaicensis bats were inoculated with two serotypes of DENV using different routes. For experimental inoculations (EI) 1 and 2, bats were inoculated subcutaneously or intraperitoneally with DENV-4; for EI-3 bats were inoculated intraperitoneally with DENV-1. Mock inoculated bats were kept as controls. In EI-4, bats were bitten by Aedes aegypti mosquitoes infected with DENV-1 or 4. Reverse transcription-polymerase chain reaction assays in plasma and spleen tissue collected from Day 1 to Days 9-17 after inoculation failed to reveal the presence of viral RNA in any of the samples. No evidence of circulating NS1 or specific anti-DENV IgG was detected in the plasma of the inoculated bats. These results indicate that A. jamaicensis bats are incapable of sustaining dengue virus replication and are unlikely to act as reservoirs for this virus. PMID:25311698

  8. Experimental Inoculation of Artibeus jamaicensis Bats with Dengue Virus Serotypes 1 or 4 Showed No Evidence of Sustained Replication

    PubMed Central

    Cabrera-Romo, Salomé; Recio-Tótoro, Benito; Alcalá, Ana C.; Lanz, Humberto; del Ángel, Rosa María; Sánchez-Cordero, Victor; Rodríguez-Moreno, Ángel; Ludert, Juan E.

    2014-01-01

    Dengue is the most important mosquito-borne viral disease to humans. Bats are potential reservoirs for flaviviruses, including dengue virus (DENV). In this work, Artibeus jamaicensis bats were inoculated with two serotypes of DENV using different routes. For experimental inoculations (EI) 1 and 2, bats were inoculated subcutaneously or intraperitoneally with DENV-4; for EI-3 bats were inoculated intraperitoneally with DENV-1. Mock inoculated bats were kept as controls. In EI-4, bats were bitten by Aedes aegypti mosquitoes infected with DENV-1 or 4. Reverse transcription-polymerase chain reaction assays in plasma and spleen tissue collected from Day 1 to Days 9–17 after inoculation failed to reveal the presence of viral RNA in any of the samples. No evidence of circulating NS1 or specific anti-DENV IgG was detected in the plasma of the inoculated bats. These results indicate that A. jamaicensis bats are incapable of sustaining dengue virus replication and are unlikely to act as reservoirs for this virus. PMID:25311698

  9. Racemic R,S-venlafaxine hydrochloride-DNA interaction: Experimental and computational evidence

    NASA Astrophysics Data System (ADS)

    Shahabadi, Nahid; Hadidi, Saba; Ghasemian, Zeinab; Taherpour, Avat(Arman)

    2015-06-01

    The interaction of racemic R,S-venlafaxine hydrochloride (rac-VEN) drug with calf thymus deoxyribonucleic acid (ct-DNA) was studied using various physico-chemical techniques and molecular docking at simulated physiological conditions (pH = 7.4). The fluorescence study shows that ct-DNA interacted with rac-VEN and quenched its intrinsic fluorescence in a static quenching process. These results are further supported by UV-Vis spectra. The binding constant of rac-VEN with ct-DNA (0.57 × 104) obtained from the spectroscopic techniques, which is more in keeping with the groove binding with DNA. Furthermore, the competition experiment using Hoechst33258 indicated that rac-VEN may bind to ct-DNA by a minor groove binding mode. In addition, iodide quenching effect on the fluorescence of rac-VEN before and after the interaction with ct-DNA is another evidence to groove binding. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrogen bonds and van der Waals interactions played major roles in the binding reaction. Molecular simulation studies carried out by using the AutoDock4 and Spartan10 programs. From the best docking map, we found that R and S-isomers fit in the A6T7T8/T19A18A17 region in minor groove of B-DNA. Finally, these results indicated that the docking of S-VEN-B-DNA is more stable than R-VEN-B-DNA.

  10. The mechanics of sill inception, propagation and growth: Experimental evidence for rapid reduction in magmatic overpressure

    NASA Astrophysics Data System (ADS)

    Kavanagh, J. L.; Boutelier, D.; Cruden, A. R.

    2015-07-01

    A model of magma propagation in the crust is presented using a series of analogue experiments, where dyed water is injected at a constant flux into layers of solidified gelatine. The gelatine layers are transparent and, when intruded, deform in an almost ideal-elastic manner under the experimental conditions (low gelatine concentration: 2.5 or 3 wt%, and low temperature: 5-10 °C). The upper gelatine layer was 1.0 to 1.5 times stiffer than the lower layer, with either a 'weak' or 'strong' interface strength between the gelatine layers. The gelatine is seeded with 20- 50 μm-diameter PMMA-RhB neutrally buoyant particles that are fluoresced by a pulsed, vertical laser sheet centred on the injection point. Digital image correlation (DIC) is used to calculate incremental strain and finite strain in the deforming host material as it is intruded. This is mapped in 2D for the developing experimental volcanic plumbing system that comprises a feeder dyke and sill. Since the gelatine deforms elastically, strain measurements correlate with stress. Our results indicate that, for constant magma flux, the moment of sill inception is characterised by a significant magmatic pressure decrease of up to ∼ 60%. This is evidenced by the rapid contraction of the feeder dyke at the moment the sill forms. Sill propagation is then controlled by the fracture properties of the weak interface, with fluid from the feeder dyke extracted to help grow the sill. Pressure drops during sill inception and growth are likely to be important in volcanic systems, where destabilisation of the magmatic plumbing system could trigger an eruption.