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Sample records for ansip explains strategy

  1. Understanding Electrochemistry Concepts Using the Predict-Observe-Explain Strategy

    ERIC Educational Resources Information Center

    Karamustafaoglu, Sevilay; Mamlok-Naaman, Rachel

    2015-01-01

    The current study deals with freshman students who study at the Department of Science at the Faculty of Education. The aim of the study was to investigate the effect of teaching electrochemistry concepts using Predict-Observe-Explain (POE) strategy. The study was quasi-experimental design using 20 students each in the experimental group (EG) and…

  2. Explaining How to Play Real-Time Strategy Games

    NASA Astrophysics Data System (ADS)

    Metoyer, Ronald; Stumpf, Simone; Neumann, Christoph; Dodge, Jonathan; Cao, Jill; Schnabel, Aaron

    Real-time strategy games share many aspects with real situations in domains such as battle planning, air traffic control, and emergency response team management which makes them appealing test-beds for Artificial Intelligence (AI) and machine learning. End user annotations could help to provide supplemental information for learning algorithms, especially when training data is sparse. This paper presents a formative study to uncover how experienced users explain game play in real-time strategy games. We report the results of our analysis of explanations and discuss their characteristics that could support the design of systems for use by experienced real-time strategy game users in specifying or annotating strategy-oriented behavior.

  3. Male reproductive strategy explains spatiotemporal segregation in brown bears

    PubMed Central

    Steyaert, Sam MJG; Kindberg, Jonas; Swenson, Jon E; Zedrosser, Andreas

    2013-01-01

    1. Spatiotemporal segregation is often explained by the risk for offspring predation or by differences in physiology, predation risk vulnerability or competitive abilities related to size dimorphism. 2. Most large carnivores are size dimorphic and offspring predation is often intraspecific and related to nonparental infanticide (NPI). NPI can be a foraging strategy, a strategy to reduce competition, or a male reproductive strategy. Spatiotemporal segregation is widespread among large carnivores, but its nature remains poorly understood. 3. We evaluated three hypotheses to explain spatiotemporal segregation in the brown bear, a size-dimorphic large carnivore in which NPI is common; the ‘NPI – foraging/competition hypothesis', i.e. NPI as a foraging strategy or a strategy to reduce competition, the ‘NPI – sexual selection hypothesis’, i.e. infanticide as a male reproductive strategy and the ‘body size hypothesis’, i.e. body-size-related differences in physiology, predation risk vulnerability or competitive ability causes spatiotemporal segregation. To test these hypotheses, we quantified spatiotemporal segregation among adult males, lone adult females and females with cubs-of-the-year, based on GPS-relocation data (2006–2010) and resource selection functions in a Scandinavian population. 4. We found that spatiotemporal segregation was strongest between females with cubs-of-the-year and adult males during the mating season. During the mating season, females with cubs-of-the-year selected their resources, in contrast to adult males, in less rugged landscapes in relative close proximity to certain human-related variables, and in more open habitat types. After the mating season, females with cubs-of-the-year markedly shifted their resource selection towards a pattern more similar to that of their conspecifics. No strong spatiotemporal segregation was apparent between females with cubs-of-the-year and conspecifics during the mating and the postmating

  4. ASL Discourse Strategies: Chaining and Connecting--Explaining across Audiences

    ERIC Educational Resources Information Center

    Quinto-Pozos, David; Reynolds, Wanette

    2012-01-01

    This study takes advantage of a novel methodology--the use of a single culturally-meaningful text written in English and presented to different audiences in ASL--to examine the ways in which Deaf native signers utilize contextualization strategies in order to match the perceived linguistic and informational needs of an audience. We demonstrate,…

  5. Diversity of immune strategies explained by adaptation to pathogen statistics

    PubMed Central

    Mayer, Andreas; Mora, Thierry; Rivoire, Olivier; Walczak, Aleksandra M.

    2016-01-01

    Biological organisms have evolved a wide range of immune mechanisms to defend themselves against pathogens. Beyond molecular details, these mechanisms differ in how protection is acquired, processed, and passed on to subsequent generations—differences that may be essential to long-term survival. Here, we introduce a mathematical framework to compare the long-term adaptation of populations as a function of the pathogen dynamics that they experience and of the immune strategy that they adopt. We find that the two key determinants of an optimal immune strategy are the frequency and the characteristic timescale of the pathogens. Depending on these two parameters, our framework identifies distinct modes of immunity, including adaptive, innate, bet-hedging, and CRISPR-like immunities, which recapitulate the diversity of natural immune systems. PMID:27432970

  6. Diversity of immune strategies explained by adaptation to pathogen statistics.

    PubMed

    Mayer, Andreas; Mora, Thierry; Rivoire, Olivier; Walczak, Aleksandra M

    2016-08-01

    Biological organisms have evolved a wide range of immune mechanisms to defend themselves against pathogens. Beyond molecular details, these mechanisms differ in how protection is acquired, processed, and passed on to subsequent generations-differences that may be essential to long-term survival. Here, we introduce a mathematical framework to compare the long-term adaptation of populations as a function of the pathogen dynamics that they experience and of the immune strategy that they adopt. We find that the two key determinants of an optimal immune strategy are the frequency and the characteristic timescale of the pathogens. Depending on these two parameters, our framework identifies distinct modes of immunity, including adaptive, innate, bet-hedging, and CRISPR-like immunities, which recapitulate the diversity of natural immune systems. PMID:27432970

  7. Female sticklebacks count alleles in a strategy of sexual selection explaining MHC polymorphism.

    PubMed

    Reusch, T B; Häberli, M A; Aeschlimann, P B; Milinski, M

    2001-11-15

    The origin and maintenance of polymorphism in major histocompatibility complex (MHC) genes in natural populations is still unresolved. Sexual selection, frequency-dependent selection by parasites and pathogens, and heterozygote advantage have been suggested to explain the maintenance of high allele diversity at MHC genes. Here we argue that there are two (non-exclusive) strategies for MHC-related sexual selection, representing solutions to two different problems: inbreeding avoidance and parasite resistance. In species prone to inadvertent inbreeding, partners should prefer dissimilar MHC genotypes to similar ones. But if the goal is to maximize the resistance of offspring towards potential infections, the choosing sex should prefer mates with a higher diversity of MHC alleles. This latter strategy should apply when there are several MHC loci, as is the case in most vertebrates. We tested the relative importance of an 'allele counting' strategy compared to a disassortative mating strategy using wild-caught three-spined sticklebacks (Gasterosteus aculeatus) from an interconnected system of lakes. Here we show that gravid female fish preferred the odour of males with a large number of MHC class-IIB alleles to that of males with fewer alleles. Females did not prefer male genotypes dissimilar to their own. PMID:11713527

  8. Relation between rainfall intensity and savanna tree abundance explained by water use strategies.

    PubMed

    Xu, Xiangtao; Medvigy, David; Rodriguez-Iturbe, Ignacio

    2015-10-20

    Tree abundance in tropical savannas exhibits large and unexplained spatial variability. Here, we propose that differentiated tree and grass water use strategies can explain the observed negative relation between maximum tree abundance and rainfall intensity (defined as the characteristic rainfall depth on rainy days), and we present a biophysical tree-grass competition model to test this idea. The model is founded on a premise that has been well established in empirical studies, namely, that the relative growth rate of grasses is much higher compared with trees in wet conditions but that grasses are more susceptible to water stress and lose biomass more quickly in dry conditions. The model is coupled with a stochastic rainfall generator and then calibrated and tested using field observations from several African savanna sites. We show that the observed negative relation between maximum tree abundance and rainfall intensity can be explained only when differentiated water use strategies are accounted for. Numerical experiments reveal that this effect is more significant than the effect of root niche separation. Our results emphasize the importance of vegetation physiology in determining the responses of tree abundance to climate variations in tropical savannas and suggest that projected increases in rainfall intensity may lead to an increase in grass in this biome. PMID:26438847

  9. LIFE HISTORY. Age-related mortality explains life history strategies of tropical and temperate songbirds.

    PubMed

    Martin, Thomas E

    2015-08-28

    Life history theory attempts to explain why species differ in offspring number and quality, growth rate, and parental effort. I show that unappreciated interactions of these traits in response to age-related mortality risk challenge traditional perspectives and explain life history evolution in songbirds. Counter to a long-standing paradigm, tropical songbirds grow at similar overall rates to temperate species but grow wings relatively faster. These growth tactics are favored by predation risk, both in and after leaving the nest, and are facilitated by greater provisioning of individual offspring by parents. Increased provisioning of individual offspring depends on partitioning effort among fewer young because of constraints on effort from adult and nest mortality. These growth and provisioning responses to mortality risk finally explain the conundrum of small clutch sizes of tropical birds. PMID:26315435

  10. Explaining the present GM business strategy on the EU food market: the gatekeepers' perspective.

    PubMed

    Inghelbrecht, Linde; Dessein, Joost; Van Huylenbroeck, Guido

    2015-01-25

    The use of genetically modified (GM) crops and their applications is partially suppressed in European Union (EU) agriculture, even if one would expect otherwise given their complementarity with the neoliberal and industrialised EU agricultural regime in place. By applying a qualitative content analysis, this paper analyses how food manufacturers and retailers (referred to as gatekeepers in the food industry) explain and defend the exclusion of GM-labelled food products on the EU market. The study design places emphasis on the role of perceptions in the strategic behaviour of gatekeepers and on the role of interaction in this regard, as we assume that the way in which gatekeepers perceive the 'rules of the game' for commercialising GM crop applications on the EU food market will be influenced by their interaction with other agribusiness actors. In a first stage, the analysis determines thematic congruence in the (types of) perceptions that explain an agribusiness actor's overall interpretation of the EU business environment for GM crop applications. This perceived 'structuring arena' (SA) for GM crop applications - as conceptualised within our framework - contains areas of either internal and external tensions, that have a compelling or non-committal influence on the agribusiness actor's interpretation. In a second stage, the analysis particularly defines how gatekeepers in the food industry perceive and experience the SA for GM crop applications on the EU market, and how these perceptual tensions subsequently influence their strategic behaviour for GM-labelled products on the EU market. Finally, we highlight how these perceptions and actions (or inaction) suppress the main changes in practice that are necessary to manage this wicked problem. PMID:25252022

  11. A General Framework of Persistence Strategies for Biological Systems Helps Explain Domains of Life

    PubMed Central

    Yafremava, Liudmila S.; Wielgos, Monica; Thomas, Suravi; Nasir, Arshan; Wang, Minglei; Mittenthal, Jay E.; Caetano-Anollés, Gustavo

    2012-01-01

    The nature and cause of the division of organisms in superkingdoms is not fully understood. Assuming that environment shapes physiology, here we construct a novel theoretical framework that helps identify general patterns of organism persistence. This framework is based on Jacob von Uexküll’s organism-centric view of the environment and James G. Miller’s view of organisms as matter-energy-information processing molecular machines. Three concepts describe an organism’s environmental niche: scope, umwelt, and gap. Scope denotes the entirety of environmental events and conditions to which the organism is exposed during its lifetime. Umwelt encompasses an organism’s perception of these events. The gap is the organism’s blind spot, the scope that is not covered by umwelt. These concepts bring organisms of different complexity to a common ecological denominator. Ecological and physiological data suggest organisms persist using three strategies: flexibility, robustness, and economy. All organisms use umwelt information to flexibly adapt to environmental change. They implement robustness against environmental perturbations within the gap generally through redundancy and reliability of internal constituents. Both flexibility and robustness improve survival. However, they also incur metabolic matter-energy processing costs, which otherwise could have been used for growth and reproduction. Lineages evolve unique tradeoff solutions among strategies in the space of what we call “a persistence triangle.” Protein domain architecture and other evidence support the preferential use of flexibility and robustness properties. Archaea and Bacteria gravitate toward the triangle’s economy vertex, with Archaea biased toward robustness. Eukarya trade economy for survivability. Protista occupy a saddle manifold separating akaryotes from multicellular organisms. Plants and the more flexible Fungi share an economic stratum, and Metazoa are locked in a positive feedback loop

  12. Behavioural strategies towards human disturbances explain individual performance in woodland caribou.

    PubMed

    Leclerc, Martin; Dussault, Christian; St-Laurent, Martin-Hugues

    2014-09-01

    Behavioural strategies may have important fitness, ecological and evolutionary consequences. In woodland caribou, human disturbances are associated with higher predation risk. Between 2004 and 2011, we investigated if habitat selection strategies of female caribou towards disturbances influenced their calf's survival in managed boreal forest with varying intensities of human disturbances. Calf survival was 53% and 43% after 30 and 90 days following birth, respectively, and 52% of calves that died were killed by black bear. The probability that a female lose its calf to predation was not influenced by habitat composition of her annual home range, but decreased with an increase in proportion of open lichen woodland within her calving home range. At the local scale, females that did not lose their calf displayed stronger avoidance of high road density areas than females that lost their calf to predation. Further, females that lost their calf to predation and that had a low proportion of ≤5-year-old cutovers within their calving home range were mostly observed in areas where these young cutovers were locally absent. Also, females that lost their calf to predation and that had a high proportion of ≤5-year-old cutovers within their calving home range were mostly observed in areas with a high local density of ≤5-year-old cutovers. Our study demonstrates that we have to account for human-induced disturbances at both local and regional scales in order to further enhance effective caribou management plans. We demonstrate that disturbances not only impact spatial distribution of individuals, but also their reproductive success. PMID:25034087

  13. Local gamete competition explains sex allocation and fertilization strategies in the sea.

    PubMed

    Henshaw, Jonathan M; Marshall, Dustin J; Jennions, Michael D; Kokko, Hanna

    2014-08-01

    Within and across taxa, there is much variation in the mode of fertilization, that is, whether eggs and/or sperm are released or kept inside or on the surface of the parent's body. Although the evolutionary consequences of fertilization mode are far-reaching, transitions in the fertilization mode itself have largely escaped theoretical attention. Here we develop the first evolutionary model of egg retention and release, which also considers transitions between hermaphroditism and dioecy as well as egg size evolution. We provide a unifying explanation for reported associations between small body size, hermaphroditism, and egg retention in marine invertebrates that have puzzled researchers for more than 3 decades. Our model, by including sperm limitation, shows that all these patterns can arise as an evolutionary response to local competition between eggs for fertilization. This can provide a general explanation for three empirical patterns: sperm casters tend to be smaller than related broadcast spawners, hermaphroditism is disproportionately common in sperm casters, and offspring of sperm casters are larger. Local gamete competition also explains a universal sexual asymmetry: females of some species retain their gametes while males release theirs, but the opposite ("egg casting") lacks evolutionary stability and is apparently not found in nature. PMID:25058290

  14. Retrieving autobiographical memories: How different retrieval strategies associated with different cues explain reaction time differences.

    PubMed

    Uzer, Tugba

    2016-02-01

    Previous research has shown that memories cued by concrete concepts, such as objects, are retrieved faster than those cued by more abstract concepts, such as emotions. This effect has been explained by the fact that more memories are directly retrieved from object versus emotion cues. In the present study, we tested whether RT differences between memories cued by emotion versus object terms occur not only because object cues elicit direct retrieval of more memories (Uzer, Lee, & Brown, 2012), but also because of differences in memory generation in response to emotions versus objects. One hundred university students retrieved memories in response to basic-level (e.g. orange), superordinate-level (e.g. plant), and emotion (e.g. surprised) cues. Retrieval speed was measured and participants reported whether memories were directly retrieved or generated on each trial. Results showed that memories were retrieved faster in response to basic-level versus superordinate-level and emotion cues because a) basic-level cues elicited more directly retrieved memories, and b) generating memories was more difficult when cues were abstract versus concrete. These results suggest that generative retrieval is a cue generation process in which additional cues that provide contextual information including the target event are produced. Memories are retrieved more slowly in response to emotion cues in part because emotion labels are less effective cues of appropriate contextual information. This particular finding is inconsistent with the idea that emotion is a primary organizational unit for autobiographical memories. In contrast, the difficulty of emotional memory generation implies that emotions represent low-level event information in the organization of autobiographical memory. PMID:26802518

  15. Lethal aggression in Pan is better explained by adaptive strategies than human impacts.

    PubMed

    Wilson, Michael L; Boesch, Christophe; Fruth, Barbara; Furuichi, Takeshi; Gilby, Ian C; Hashimoto, Chie; Hobaiter, Catherine L; Hohmann, Gottfried; Itoh, Noriko; Koops, Kathelijne; Lloyd, Julia N; Matsuzawa, Tetsuro; Mitani, John C; Mjungu, Deus C; Morgan, David; Muller, Martin N; Mundry, Roger; Nakamura, Michio; Pruetz, Jill; Pusey, Anne E; Riedel, Julia; Sanz, Crickette; Schel, Anne M; Simmons, Nicole; Waller, Michel; Watts, David P; White, Frances; Wittig, Roman M; Zuberbühler, Klaus; Wrangham, Richard W

    2014-09-18

    Observations of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) provide valuable comparative data for understanding the significance of conspecific killing. Two kinds of hypothesis have been proposed. Lethal violence is sometimes concluded to be the result of adaptive strategies, such that killers ultimately gain fitness benefits by increasing their access to resources such as food or mates. Alternatively, it could be a non-adaptive result of human impacts, such as habitat change or food provisioning. To discriminate between these hypotheses we compiled information from 18 chimpanzee communities and 4 bonobo communities studied over five decades. Our data include 152 killings (n = 58 observed, 41 inferred, and 53 suspected killings) by chimpanzees in 15 communities and one suspected killing by bonobos. We found that males were the most frequent attackers (92% of participants) and victims (73%); most killings (66%) involved intercommunity attacks; and attackers greatly outnumbered their victims (median 8:1 ratio). Variation in killing rates was unrelated to measures of human impacts. Our results are compatible with previously proposed adaptive explanations for killing by chimpanzees, whereas the human impact hypothesis is not supported. PMID:25230664

  16. Linking GPS Telemetry Surveys and Scat Analyses Helps Explain Variability in Black Bear Foraging Strategies

    PubMed Central

    Lesmerises, Rémi; Rebouillat, Lucie; Dussault, Claude; St-Laurent, Martin-Hugues

    2015-01-01

    Studying diet is fundamental to animal ecology and scat analysis, a widespread approach, is considered a reliable dietary proxy. Nonetheless, this method has weaknesses such as non-random sampling of habitats and individuals, inaccurate evaluation of excretion date, and lack of assessment of inter-individual dietary variability. We coupled GPS telemetry and scat analyses of black bears Ursus americanus Pallas to relate diet to individual characteristics and habitat use patterns while foraging. We captured 20 black bears (6 males and 14 females) and fitted them with GPS/Argos collars. We then surveyed GPS locations shortly after individual bear visits and collected 139 feces in 71 different locations. Fecal content (relative dry matter biomass of ingested items) was subsequently linked to individual characteristics (sex, age, reproductive status) and to habitats visited during foraging bouts using Brownian bridges based on GPS locations prior to feces excretion. At the population level, diet composition was similar to what was previously described in studies on black bears. However, our individual-based method allowed us to highlight different intra-population patterns, showing that sex and female reproductive status had significant influence on individual diet. For example, in the same habitats, females with cubs did not use the same food sources as lone bears. Linking fecal content (i.e., food sources) to habitat previously visited by different individuals, we demonstrated a potential differential use of similar habitats dependent on individual characteristics. Females with cubs-of-the-year tended to use old forest clearcuts (6–20 years old) to feed on bunchberry, whereas females with yearling foraged for blueberry and lone bears for ants. Coupling GPS telemetry and scat analyses allows for efficient detection of inter-individual or inter-group variations in foraging strategies and of linkages between previous habitat use and food consumption, even for cryptic

  17. A longitudinal study to explain strategies to change weight and muscles among normal weight and overweight children.

    PubMed

    McCabe, M P; Ricciardelli, L A; Holt, K

    2005-12-01

    Previous research has indicated that both boys and girls strive for a slim body, with boys having an additional focus on a muscular body build. The current study was designed to evaluate the utility of a biopsychosocial model to explain body image and body change strategies among children. The study evaluated changes over time in body image and strategies to lose weight and increase muscles among 132 normal weight and 67 overweight boys (mean age = 9.23 years) and 158 normal weight and 55 overweight girls (mean age = 9.33 years). The predictive role of BMI, positive and negative affect, self-esteem and perceived sociocultural pressures to lose weight or increase muscle on body image and body change strategies over a 16 month period was evaluated. All participants completed the questionnaire on both occasions. The results demonstrated that both overweight boys and girls were more likely to be dissatisfied with their weight, place more importance on their weight, engage in more strategies to lose weight as well as perceive more pressure to lose weight. Overweight boys and girls were also more likely to report lower levels of self-esteem and positive affect, and higher levels of negative affect, and reported a reduction in their self-esteem over time. Regression analyses demonstrated that among overweight boys, low self-esteem and high levels of perceived pressure to lose weight predicted weight dissatisfaction; for overweight girls, weight dissatisfaction was also predicted by low levels of self-esteem. The implication of these findings in terms of factors contributing to the adoption of health risk behaviors among children is discussed. PMID:16182409

  18. Protein costs do not explain evolution of metabolic strategies and regulation of ribosomal content: does protein investment explain an anaerobic bacterial Crabtree effect?

    PubMed

    Goel, Anisha; Eckhardt, Thomas H; Puri, Pranav; de Jong, Anne; Branco Dos Santos, Filipe; Giera, Martin; Fusetti, Fabrizia; de Vos, Willem M; Kok, Jan; Poolman, Bert; Molenaar, Douwe; Kuipers, Oscar P; Teusink, Bas

    2015-07-01

    Protein investment costs are considered a major driver for the choice of alternative metabolic strategies. We tested this premise in Lactococcus lactis, a bacterium that exhibits a distinct, anaerobic version of the bacterial Crabtree/Warburg effect; with increasing growth rates it shifts from a high yield metabolic mode [mixed-acid fermentation; 3 adenosine triphosphate (ATP) per glucose] to a low yield metabolic mode (homolactic fermentation; 2 ATP per glucose). We studied growth rate-dependent relative transcription and protein ratios, enzyme activities, and fluxes of L. lactis in glucose-limited chemostats, providing a high-quality and comprehensive data set. A three- to fourfold higher growth rate rerouted metabolism from acetate to lactate as the main fermentation product. However, we observed hardly any changes in transcription, protein levels and enzyme activities. Even levels of ribosomal proteins, constituting a major investment in cellular machinery, changed only slightly. Thus, contrary to the original hypothesis, central metabolism in this organism appears to be hardly regulated at the level of gene expression, but rather at the metabolic level. We conclude that L. lactis is either poorly adapted to growth at low and constant glucose concentrations, or that protein costs play a less important role in fitness than hitherto assumed. PMID:25828364

  19. The role of research-article writing motivation and self-regulatory strategies in explaining research-article abstract writing ability.

    PubMed

    Lin, Ming-Chia; Cheng, Yuh-Show; Lin, Sieh-Hwa; Hsieh, Pei-Jung

    2015-04-01

    The purpose of the study was to investigate the effects of research-article writing motivation and use of self-regulatory writing strategies in explaining second language (L2) research-article abstract writing ability, alongside the L2 literacy effect. Four measures were administered: a L2 literacy test, a research abstract performance assessment, and inventories of writing motivation and strategy. Participants were L2 graduate students in Taiwan (N=185; M age=25.8 yr., SD=4.5, range=22-53). Results of structural equation modeling showed a direct effect of motivation on research-article writing ability, but no direct effect of strategy or indirect effect of motivation via strategy on research-article writing ability, with L2 literacy controlled. The findings suggest research-article writing instruction should address writing motivation, besides L2 literacy. PMID:25706344

  20. Explaining the unexplainable: designing a national strategy on classroom communication concerning the 22 July terror attack in Norway

    PubMed Central

    Schultz, Jon-Håkon; Langballe, Åse; Raundalen, Magne

    2014-01-01

    Background In the context of crisis and disasters, school-aged children are a vulnerable group with fewer coping resources than adults. The school is a key arena for preventive interventions; teachers can be given a key role in large-scale school-based interventions following a man-made or natural disaster. Objectives This paper describes a practical example of designing a school-based population-level intervention. Methods The preventive measures were delivered as a national communication strategy between teachers and pupils aged 6–19 concerning the terror attack on 22 July 2011 in Norway. The strategy is based on principles from international research. Results The presentation contributes to the discussion of defining the teacher's role in school-based crisis interventions and dealing with high-intensity media coverage of war, terror, and catastrophes. Conclusions The presentation provides educational and psychological perspectives on how teachers can take an active role in helping pupils to deal with such events through two approaches: the therapeutic approach, to restore calm and feelings of safety; and the educational approach, to foster reflection and deeper understanding. PMID:25018859

  1. A process-driven sedimentary habitat modelling approach, explaining seafloor integrity and biodiversity assessment within the European Marine Strategy Framework Directive

    NASA Astrophysics Data System (ADS)

    Galparsoro, Ibon; Borja, Ángel; Kostylev, Vladimir E.; Rodríguez, J. Germán; Pascual, Marta; Muxika, Iñigo

    2013-10-01

    The Marine Strategy Framework Directive (MSFD) seeks to achieve good environmental status, by 2020, for European seas. This study analyses the applicability of a process-driven benthic sedimentary habitat model, to be used in the implementation of the MSFD in relation to biodiversity and seafloor integrity descriptors for sedimentary habitats. Our approach maps the major environmental factors influencing soft-bottom macrobenthic community structure and the life-history traits of species. Among the 16 environmental variables considered, a combination of water depth, mean grain size, a wave-induced sediment resuspension index and annual bottom maximum temperature, are the most significant factors explaining the variability in the structure of benthic communities in the study area. These variables are classified into those representing the ‘Disturbance' and ‘Scope for Growth' components of the environment. It was observed that the habitat classes defined in the process-driven model reflected different structural and functional characteristics of the benthos. Moreover, benthic community structure anomalies due to human pressures could also be detected within the model produced. Thus, the final process-driven habitat map can be considered as being highly useful for seafloor integrity and biodiversity assessment, within the European MSFD as well as for conservation, environmental status assessment and managing human activities, especially within the marine spatial planning process.

  2. Diverging drought-tolerance strategies explain tree species distribution along a fog-dependent moisture gradient in a temperate rain forest.

    PubMed

    Negret, Beatriz Salgado; Pérez, Fernanda; Markesteijn, Lars; Castillo, Mylthon Jiménez; Armesto, Juan J

    2013-11-01

    The study of functional traits and physiological mechanisms determining species' drought tolerance is important for the prediction of their responses to climatic change. Fog-dependent forest patches in semiarid regions are a good study system with which to gain an understanding of species' responses to increasing aridity and patch fragmentation. Here we measured leaf and hydraulic traits for three dominant species with contrasting distributions within patches in relict, fog-dependent forests in semiarid Chile. In addition, we assessed pressure-volume curve parameters in trees growing at a dry leeward edge and wet patch core. We predicted species would display contrasting suites of traits according to local water availability: from one end favoring water conservation and reducing cavitation risk, and from the opposite end favoring photosynthetic and hydraulic efficiency. Consistent with our hypothesis, we identified a continuum of water use strategies explaining species distribution along a small-scale moisture gradient. Drimys winteri, a tree restricted to the humid core, showed traits allowing efficient water transport and high carbon gain; in contrast, Myrceugenia correifolia, a tree that occurs in the drier patch edges, exhibited traits promoting water conservation and lower gas exchange rates, as well low water potential at turgor loss point. The most widespread species, Aextoxicon punctatum, showed intermediate trait values. Osmotic compensatory mechanism was detected in M. correifolia, but not in A. punctatum. We show that partitioning of the pronounced soil moisture gradients from patch cores to leeward edges among tree species is driven by differential drought tolerance. Such differences indicate that trees have contrasting abilities to cope with future reductions in soil moisture. PMID:23576107

  3. Can the life-history strategy explain the success of the exotic trees Ailanthus altissima and Robinia pseudoacacia in Iberian floodplain forests?

    PubMed

    Castro-Díez, Pilar; Valle, Guillermo; González-Muñoz, Noelia; Alonso, Álvaro

    2014-01-01

    Ailanthus altissima and Robina pseudoacacia are two successful invasive species of floodplains in central Spain. We aim to explain their success as invaders in this habitat by exploring their phenological pattern, vegetative and sexual reproductive growth, and allometric relations, comparing them with those of the dominant native tree Populus alba. During a full annual cycle we follow the timing of vegetative growth, flowering, fruit set, leaf abscission and fruit dispersal. Growth was assessed by harvesting two-year old branches at the peaks of vegetative, flower and fruit production and expressing the mass of current-year leaves, stems, inflorescences and infrutescences per unit of previous-year stem mass. Secondary growth was assessed as the increment of trunk basal area per previous-year basal area. A. altissima and R. pseudoacacia showed reproductive traits (late flowering phenology, insect pollination, late and long fruit set period, larger seeds) different from P. alba and other native trees, which may help them to occupy an empty reproductive niche and benefit from a reduced competition for the resources required by reproductive growth. The larger seeds of the invaders may make them less dependent on gaps for seedling establishment. If so, these invaders may benefit from the reduced gap formation rate of flood-regulated rivers of the study region. The two invasive species showed higher gross production than the native, due to the higher size of pre-existing stems rather than to a faster relative growth rate. The latter was only higher in A. altissima for stems, and in R. pseudoacacia for reproductive organs. A. altissima and R. pseudoacacia showed the lowest and highest reproductive/vegetative mass ratio, respectively. Therefore, A. altissima may outcompete native P. alba trees thanks to a high potential to overtop coexisting plants whereas R. pseudoacacia may do so by means of a higher investment in sexual reproduction. PMID:24937651

  4. Can the Life-History Strategy Explain the Success of the Exotic Trees Ailanthus altissima and Robinia pseudoacacia in Iberian Floodplain Forests?

    PubMed Central

    Castro-Díez, Pilar; Valle, Guillermo; González-Muñoz, Noelia; Alonso, Álvaro

    2014-01-01

    Ailanthus altissima and Robina pseudoacacia are two successful invasive species of floodplains in central Spain. We aim to explain their success as invaders in this habitat by exploring their phenological pattern, vegetative and sexual reproductive growth, and allometric relations, comparing them with those of the dominant native tree Populus alba. During a full annual cycle we follow the timing of vegetative growth, flowering, fruit set, leaf abscission and fruit dispersal. Growth was assessed by harvesting two-year old branches at the peaks of vegetative, flower and fruit production and expressing the mass of current-year leaves, stems, inflorescences and infrutescences per unit of previous-year stem mass. Secondary growth was assessed as the increment of trunk basal area per previous-year basal area. A. altissima and R. pseudoacacia showed reproductive traits (late flowering phenology, insect pollination, late and long fruit set period, larger seeds) different from P. alba and other native trees, which may help them to occupy an empty reproductive niche and benefit from a reduced competition for the resources required by reproductive growth. The larger seeds of the invaders may make them less dependent on gaps for seedling establishment. If so, these invaders may benefit from the reduced gap formation rate of flood-regulated rivers of the study region. The two invasive species showed higher gross production than the native, due to the higher size of pre-existing stems rather than to a faster relative growth rate. The latter was only higher in A. altissima for stems, and in R. pseudoacacia for reproductive organs. A. altissima and R. pseudoacacia showed the lowest and highest reproductive/vegetative mass ratio, respectively. Therefore, A. altissima may outcompete native P. alba trees thanks to a high potential to overtop coexisting plants whereas R. pseudoacacia may do so by means of a higher investment in sexual reproduction. PMID:24937651

  5. Explaining cloud chamber tracks

    SciTech Connect

    Broyles, A.A.

    1992-06-16

    The operation of many detection devices is usually explained in terms of the ionization tracks produced by particles despite the fact that the corresponding incident wave functions extended over the entire sensitive regions of the detectors. The mechanisms by which the wave function appears to collapse to a track is analyzed here.

  6. Explaining the Interpretive Mind.

    ERIC Educational Resources Information Center

    Brockmeier, Jens

    1996-01-01

    Examines two prominent positions in the epistemological foundations of psychology--Piaget's causal explanatory claims and Vygotsky's interpretive understanding; contends that they need to be placed in their wider philosophical contexts. Argues that the danger of causally explaining cultural practices through which human beings construct and…

  7. Explaining the gender wealth gap.

    PubMed

    Ruel, Erin; Hauser, Robert M

    2013-08-01

    To assess and explain the United States' gender wealth gap, we use the Wisconsin Longitudinal Study to examine wealth accumulated by a single cohort over 50 years by gender, by marital status, and limited to the respondents who are their family's best financial reporters. We find large gender wealth gaps between currently married men and women, and between never-married men and women. The never-married accumulate less wealth than the currently married, and there is a marital disruption cost to wealth accumulation. The status-attainment model shows the most power in explaining gender wealth gaps between these groups explaining about one-third to one-half of the gap, followed by the human-capital explanation. In other words, a lifetime of lower earnings for women translates into greatly reduced wealth accumulation. After controlling for the full model, we find that a gender wealth gap remains between married men and women that we speculate may be related to gender differences in investment strategies and selection effects. PMID:23264038

  8. Explaining wartime rape.

    PubMed

    Gottschall, Jonathan

    2004-05-01

    In the years since the first reports of mass rapes in the Yugoslavian wars of secession and the genocidal massacres in Rwanda, feminist activists and scholars, human rights organizations, journalists, and social scientists have dedicated unprecedented efforts to document, explain, and seek solutions for the phenomenon of wartime rape. While contributors to this literature agree on much, there is no consensus on causal factors. This paper provides a brief overview of the literature on wartime rape in historical and ethnographical societies and a critical analysis of the four leading explanations for its root causes: the feminist theory, the cultural pathology theory, the strategic rape theory, and the biosocial theory. The paper concludes that the biosocial theory is the only one capable of bringing all the phenomena associated with wartime rape into a single explanatory context. PMID:15326538

  9. Explaining moral religions.

    PubMed

    Baumard, Nicolas; Boyer, Pascal

    2013-06-01

    Moralizing religions, unlike religions with morally indifferent gods or spirits, appeared only recently in some (but not all) large-scale human societies. A crucial feature of these new religions is their emphasis on proportionality (between deeds and supernatural rewards, between sins and penance, and in the formulation of the Golden Rule, according to which one should treat others as one would like others to treat oneself). Cognitive science models that account for many properties of religion can be extended to these religions. Recent models of evolved dispositions for fairness in cooperation suggest that proportionality-based morality is highly intuitive to human beings. The cultural success of moralizing movements, secular or religious, could be explained based on proportionality. PMID:23664451

  10. Jupiter's Gossamer Rings Explained.

    NASA Astrophysics Data System (ADS)

    Hamilton, D. P.

    2003-05-01

    Over the past several years, Galileo measurements and groundbased imaging have drastically improved our knowledge of Jupiter's faint ring system. We now recognize that the ring consists of four components: a main ring 7000km wide, whose inner edge blossoms into a vertically-extended halo, and a pair of more tenuous Gossamer rings, one associated with each of the small moons Thebe and Amalthea. When viewed edge on, the Gossamer rings appear as diaphanous disks whose thicknesses agree with the vertical excursions of the inclined satellites from the equatorial plane. In addition, the brightness of each Gossamer ring drops off sharply outside the satellite orbits. These correlations allowed Burns etal (1999, Science, 284, 1146) to argue convincingly that the satellites act as sources of the dusty ring material. In addition, since most material is seen inside the orbits of the source satellites, an inwardly-acting dissipative force such as Poynting-Robertson drag is implicated. The most serious problem with this simple and elegant picture is that it is unable to explain the existence of a faint swath of material that extends half a jovian radius outward from Thebe. A key constraint is that this material has the same thickness as the rest of the Thebe ring. In this work, we identify the mechanism responsible for the outward extension: it is a shadow resonance, first investigated by Horanyi and Burns (1991, JGR, 96, 19283). When a dust grain enters Jupiter's shadow, photoelectric processes shut down and the grain's electric charge becomes more negative. The electromagnetic forces associated with the varying charge cause periodic oscillations in the orbital eccentricity and semimajor axis as the orbital pericenter precesses. This results in a ring which spreads both inward and outward of its source satellite while preserving its vertical thickness - just as is observed for the Thebe ring. Predictions of the model are: i) gaps of micron-sized material interior to Thebe and

  11. What explains consciousness? Or…What consciousness explains?

    PubMed

    Dulany, Donelson E

    2014-01-01

    In this invited commentary I focus on the topic addressed in three papers: De Sousa's (2013[1617]) Toward an Integrative Theory of Consciousness, a monograph with Parts 1 & 2, as well as commentaries by Pereira (2013a[59]) and Hirstein (2013[42]). All three are impressively scholarly and can stand-and shout-on their own. But theory of consciousness? My aim is to slice that topic into the two fundamentally different kinds of theories of consciousness, say what appears to be an ideology, out of behaviourism into cognitivism, now also influencing the quest for an "explanation of consciousness" in cognitive neuroscience. I will then say what can be expected given what we know of the complexity of brain structure, the richness of a conscious "vocabulary", and current technological limits of brain imaging. This will then turn to the strategy for examining "what consciousness explains"-metatheory, theories, mappings, and a methodology of competitive support, a methodology especially important where there are competing commitments. There are also increasingly common identifications of methodological bias in, along with failures to replicate, studies reporting unconscious controls in decision, social priming-as there have been in perception, learning, problem solving, etc. The literature critique has provided evidence taken as reducing, and in some cases eliminating, a role for conscious controls-a position consistent with that ideology out of behaviourism into cognitivism. It is an ideological position that fails to recognize the fundamental distinction between theoretical and metaphysical assertions. PMID:24891796

  12. Your Radiologist Explains CT Colonography

    MedlinePlus Videos and Cool Tools

    ... About this Site RadiologyInfo.org is produced by: Image/Video Gallery Your Radiologist Explains CT Colonography (Virtual ... to allow for inflation with air while CT images are being taken. If you’re scheduled for ...

  13. Your Radiologist Explains Nuclear Medicine

    MedlinePlus Videos and Cool Tools

    ... by: Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org Hello! ... d like to talk to you about nuclear medicine. Nuclear medicine offers the potential to identify disease ...

  14. Can Marxism Explain America's Racism?

    ERIC Educational Resources Information Center

    Willhelm, Sidney M.

    1980-01-01

    The Marxist interpretation of the Black experience in America has always had difficulty explaining various noneconomic aspects of racism. A perspective is needed that can blend racism as a variable in relationship with economic variables. To reach this perspective, the labor process within capitalism must be more fully understood. (Author/GC)

  15. Explaining Errors in Children's Questions

    ERIC Educational Resources Information Center

    Rowland, Caroline F.

    2007-01-01

    The ability to explain the occurrence of errors in children's speech is an essential component of successful theories of language acquisition. The present study tested some generativist and constructivist predictions about error on the questions produced by ten English-learning children between 2 and 5 years of age. The analyses demonstrated that,…

  16. Explaining Different Discourse Strategies in Cross-Cultural Business Negotiations.

    ERIC Educational Resources Information Center

    Lim, Cheng-Geok

    Some language features are described that could account for feelings of people from different cultures not being on the same "wave length" when they communicate with each other in business negotiations. Candlin's explanatory approach involving a "top-down, bottom-up" methodology is used. It views language as being indeterminate and allows language…

  17. Root traits explain different foraging strategies between resprouting life histories.

    PubMed

    Paula, Susana; Pausas, Juli G

    2011-02-01

    Drought and fire are prevalent disturbances in Mediterranean ecosystems. Plant species able to regrow after severe disturbances (i.e. resprouter life history) have higher allocation to roots and higher water potential during the dry season than coexisting non-resprouting species. However, seedlings of non-resprouters have a higher survival rate after summer drought. We predict that, to counteract their shallow-rooting systems and to maximize seedling survival, non-resprouters have root traits that confer higher efficiency in soil resource acquisition than resprouters. We tested this prediction in seedlings of less than 1.5 months old. We select 13 coexisting woody species (including both resprouters and non-resprouters), grew them in a common garden and measured the following root traits: length, surface, average diameter, root tissue density (RTD), specific root length (SRL), surface:volume ratio (SVR), specific tip density (STD), tip distribution in depth, internal links ratio (ILR), and degree of branching. These root traits were compared between the two resprouting life histories using both standard cross-species and phylogenetic-informed analysis. Non-resprouters showed higher SRL and longer, thinner and more branched laterals, especially in the upper soil layers. The external links (i.e. the most absorptive root region) were also more abundant, longer, thinner and with higher SVR for non-resprouters. The results were supported by the phylogenetic-informed analysis for the root traits most strongly related to soil resource acquisition (SRL, SVR and branching pattern). The seedling root structure of non-resprouters species allows them to more efficiently explore the upper soil layer, whereas seedling roots of resprouters will permit both carbon storage and deep soil penetration. PMID:20960009

  18. Explaining mirror-touch synesthesia.

    PubMed

    Ward, Jamie; Banissy, Michael J

    2015-01-01

    Mirror-touch synesthesia (MTS) is the conscious experience of tactile sensations induced by seeing someone else touched. This paper considers two different, although not mutually exclusive, theoretical explanations and, in the final section, considers the relation between MTS and other forms of synesthesia and also other kinds of vicarious perception (e.g., contagious yawning). The Threshold Theory explains MTS in terms of hyper-activity within a mirror system for touch and/or pain. This offers a good account for some of the evidence (e.g., from fMRI) but fails to explain the whole pattern (e.g., structural brain differences outside of this system; performance on some tests of social cognition). The Self-Other Theory explains MTS in terms of disturbances in the ability to distinguish the self from others. This can be construed in terms of over-extension of the bodily self in to others, or as difficulties in the control of body-based self-other representations. In this account, MTS is a symptom of a broader cognitive profile. We suggest this meets the criteria for synesthesia, despite the proximal causal mechanisms remaining largely unknown, and that the tendency to localize vicarious sensory experiences distinguishes it from other kinds of seemingly related phenomena (e.g., non-localized affective responses to observing pain). PMID:25893437

  19. Towards Explaining the Water Siphon

    NASA Astrophysics Data System (ADS)

    Jumper, William D.; Stanchev, Boris

    2014-11-01

    Many high school and introductory college physics courses cover topics in fluidics through the Bernoulli and Poiseuille equations, and consequently one might think that siphons should present an excellent opportunity to engage students in various laboratory measurement exercises incorporating these fascinating devices. However, the flow rates (or average exit velocities) of simple water siphons have not been sufficiently explained,1 nor has an associated analytical model been developed demonstrating sufficient experimental correspondence to allow physics instructors to bring closure between theoretical concepts and laboratory experiences. We present such an explanation and analytical model for the flow rates of simple water tube siphons. Further, we report measurements that show the model gives good correspondence to flow rates of siphons over a wide range of tube lengths, inner diameters, and water heights (hydrostatic head), and for which the Reynolds numbers range from 102 to 105.

  20. Dark antiatoms can explain DAMA

    NASA Astrophysics Data System (ADS)

    Wallemacq, Quentin; Cudell, Jean-René

    2015-02-01

    We show that the existence of a sub-dominant form of dark matter, made of dark "antiatoms" of mass m~ 1 TeV and size dot a0~ 3 fm, can explain the results of direct detection experiments, with a positive signal in DAMA/NaI and DAMA/LIBRA and no signal in other experiments. The signal comes from the binding of the dark antiatoms to thallium, a dopant in DAMA, and is not present for the constituent atoms of other experiments. The dark antiatoms are made of two particles oppositely charged under a dark U(1) symmetry and can bind to terrestrial atoms because of a kinetic mixing between the photon and the massless dark photon, such that the dark particles acquire an electric millicharge ~ ± 5.10-4e. This millicharge enables them to bind to high-Z atoms via radiative capture, after they thermalize in terrestrial matter through elastic collisions.

  1. The Effect of Self-Explaining on Robust Learning

    ERIC Educational Resources Information Center

    Hausmann, Robert G. M.; VanLehn, Kurt

    2010-01-01

    Self-explaining is a domain-independent learning strategy that generally leads to a robust understanding of the domain material. However, there are two potential explanations for its effectiveness. First, self-explanation generates additional "content" that does not exist in the instructional materials. Second, when compared to comprehension,…

  2. Dark antiatoms can explain DAMA

    SciTech Connect

    Wallemacq, Quentin; Cudell, Jean-René E-mail: jr.cudell@ulg.ac.be

    2015-02-01

    We show that the existence of a sub-dominant form of dark matter, made of dark ''antiatoms'' of mass m∼ 1 TeV and size a-dot {sub 0}∼ 3 fm, can explain the results of direct detection experiments, with a positive signal in DAMA/NaI and DAMA/LIBRA and no signal in other experiments. The signal comes from the binding of the dark antiatoms to thallium, a dopant in DAMA, and is not present for the constituent atoms of other experiments. The dark antiatoms are made of two particles oppositely charged under a dark U(1) symmetry and can bind to terrestrial atoms because of a kinetic mixing between the photon and the massless dark photon, such that the dark particles acquire an electric millicharge ∼ ± 5.10{sup −4}e. This millicharge enables them to bind to high-Z atoms via radiative capture, after they thermalize in terrestrial matter through elastic collisions.

  3. Explain bioinformatics to your grandmother!

    PubMed

    Bernard, Virginie; Michaut, Magali

    2013-10-01

    What are you working on? You have certainly been asked that question many times, whether it be at a Saturday night party, during a discussion with your neighbors, or at a family gathering. Communicating with a lay audience about scientific subjects and making them attractive is a difficult task. But difficult or not, you will have to do it for many years, not only with your family and friends, but also with your colleagues and collaborators. So, better learn now! Although not usually taught, the ability to explain your work to others is an essential skill in science, where communication plays a key role. Using some examples of the French Regional Student Group activities, we discuss here (i) why it is important to have such communication skills, (ii) how you can get involved in these activities by using existing resources or working with people who have previous experience, and (iii) what you get out of this amazing experience. We aim to motivate you and provide you with tips and ideas to get involved in promoting scientific activities while getting all the benefits. PMID:24204239

  4. What Explains Consciousness? Or…What Consciousness Explains?

    PubMed Central

    Dulany, Donelson E.

    2014-01-01

    In this invited commentary I focus on the topic addressed in three papers: De Sousa's (2013[1617]) Toward an Integrative Theory of Consciousness, a monograph with Parts 1 & 2, as well as commentaries by Pereira (2013a[59]) and Hirstein (2013[42]). All three are impressively scholarly and can stand—and shout—on their own. But theory of consciousness? My aim is to slice that topic into the two fundamentally different kinds of theories of consciousness, say what appears to be an ideology, out of behaviourism into cognitivism, now also influencing the quest for an “explanation of consciousness” in cognitive neuroscience. I will then say what can be expected given what we know of the complexity of brain structure, the richness of a conscious “vocabulary”, and current technological limits of brain imaging. This will then turn to the strategy for examining “what consciousness explains”—metatheory, theories, mappings, and a methodology of competitive support, a methodology especially important where there are competing commitments. There are also increasingly common identifications of methodological bias in, along with failures to replicate, studies reporting unconscious controls in decision, social priming—as there have been in perception, learning, problem solving, etc. The literature critique has provided evidence taken as reducing, and in some cases eliminating, a role for conscious controls—a position consistent with that ideology out of behaviourism into cognitivism. It is an ideological position that fails to recognize the fundamental distinction between theoretical and metaphysical assertions. PMID:24891796

  5. Strategies for Success.

    ERIC Educational Resources Information Center

    Harris, J. Jerome

    1990-01-01

    Rather than use their energies to explain their failures, Blacks need to develop strategies for success. Uses examples from the Atlanta Public Schools to illustrate how Blacks can use effective schools research to improve urban, Black education. (FMW)

  6. Using Plant Functional Traits to Explain Diversity–Productivity Relationships

    PubMed Central

    Roscher, Christiane; Schumacher, Jens; Gubsch, Marlén; Lipowsky, Annett; Weigelt, Alexandra; Buchmann, Nina; Schmid, Bernhard; Schulze, Ernst-Detlef

    2012-01-01

    Background The different hypotheses proposed to explain positive species richness–productivity relationships, i.e. selection effect and complementarity effect, imply that plant functional characteristics are at the core of a mechanistic understanding of biodiversity effects. Methodology/Principal Findings We used two community-wide measures of plant functional composition, (1) community-weighted means of trait values (CWM) and (2) functional trait diversity based on Rao’s quadratic diversity (FDQ) to predict biomass production and measures of biodiversity effects in experimental grasslands (Jena Experiment) with different species richness (2, 4, 8, 16 and 60) and different functional group number and composition (1 to 4; legumes, grasses, small herbs, tall herbs) four years after establishment. Functional trait composition had a larger predictive power for community biomass and measures of biodiversitity effects (40–82% of explained variation) than species richness per se (<1–13% of explained variation). CWM explained a larger amount of variation in community biomass (80%) and net biodiversity effects (70%) than FDQ (36 and 38% of explained variation respectively). FDQ explained similar proportions of variation in complementarity effects (24%, positive relationship) and selection effects (28%, negative relationship) as CWM (27% of explained variation for both complementarity and selection effects), but for all response variables the combination of CWM and FDQ led to significant model improvement compared to a separate consideration of different components of functional trait composition. Effects of FDQ were mainly attributable to diversity in nutrient acquisition and life-history strategies. The large spectrum of traits contributing to positive effects of CWM on biomass production and net biodiversity effects indicated that effects of dominant species were associated with different trait combinations. Conclusions/Significance Our results suggest that the

  7. Modeling factors explaining physicians’ satisfaction with competence

    PubMed Central

    Lepnurm, Rein; Dobson, Roy Thomas; Peña-Sánchez, Juan-Nicolás; Nesdole, Robert

    2015-01-01

    Objective: Attention to physician wellness has increased as medical practice gains in complexity. Physician satisfaction with practice is critical for quality of care and practice growth. The purpose of this study was to model physicians’ self-reported Satisfaction with Competence as a function of their perceptions of the Quality of Health Services, Distress, Coping, Practice Management, Personal Satisfaction and Professional Equity. Methods: Comprehensive questionnaires were sent to a stratified sample of 5300 physicians across Canada. This cross-sectional study focused on physicians who examined and treated individual patients for a final study population of 2639 physicians. Response bias was negligible. The questionnaires contained measures of Satisfaction with Competence, Quality of Health Services, Distress, Coping, Personal Satisfaction, Practice Management and Professional Equity. Exploring relationships was done using Pearson correlations and one-way analysis of variance. Modeling was by hierarchical regressions. Results: The measures were reliable: Satisfaction with Competence (α = .86), Quality (α = .86), Access (α = .82), Distress (α = .82), Coping (α = .76), Personal Satisfaction (α = .78), Practice Management (α = .89) and the dimensions of Professional Equity (Fulfillment, α = .81; Financial, α = .93; and Recognition, α = .75) with comparative validity. Satisfaction with Competence was positively correlated with Quality (r = .32), Efficiency (r = .37) and Access (r = .32); negatively correlated with Distress (r = −.54); and positively correlated with Coping strategies (r = .43), Personal Satisfaction (r = .57), Practice Management (r = .17), Fulfillment (r = .53), Financial (r = .36) and Recognition (r = .54). Physicians’ perceptions on Quality, Efficiency, Access, Distress, Coping, Personal Satisfaction, Practice Management, Fulfillment, Pay and

  8. Topology Explains Why Automobile Sunshades Fold Oddly

    ERIC Educational Resources Information Center

    Feist, Curtis; Naimi, Ramin

    2009-01-01

    Automobile sunshades always fold into an "odd" number of loops. The explanation why involves elementary topology (braid theory and linking number, both explained in detail here with definitions and examples), and an elementary fact from algebra about symmetric group.

  9. Prompting Strategies for Introducing Opera.

    ERIC Educational Resources Information Center

    Beck, Charles R.

    2002-01-01

    Describes how to introduce opera to students through the use of prompting strategies. Explains that these strategies encourage active participation by students and help to improve listening skills. Focuses on prompting strategies, such as matching characters to songs, identifying, and sequencing songs. (CMK)

  10. Explained variation for recurrent event data.

    PubMed

    Alotaibi, Refah; Fiaccone, Rosemeire; Henderson, Robin; Stare, Janez

    2015-07-01

    Although there are many suggested measures of explained variation for single-event survival data, there has been little attention to explained variation for recurrent event data. We describe an existing rank-based measure and we investigate a new statistic based on observed and expected event count processes. Both methods can be used for all models. Adjustments for missing data are proposed and demonstrated through simulation to be effective. We compare the population values of the two statistics and illustrate their use in comparing an array of non-nested models for data on recurrent episodes of infant diarrhoea. PMID:25899247

  11. Mining and Explaining Relationships in Wikipedia

    NASA Astrophysics Data System (ADS)

    Zhang, Xinpeng; Asano, Yasuhito; Yoshikawa, Masatoshi

    Mining and explaining relationships between concepts are challenging tasks in the field of knowledge search. We propose a new approach for the tasks using disjoint paths formed by links in Wikipedia. Disjoint paths are easy to understand and do not contain redundant information. To achieve this approach, we propose a naive method, as well as a generalized flow based method, and a technique for mining more disjoint paths using the generalized flow based method. We also apply the approach to classification of relationships. Our experiments reveal that the generalized flow based method can mine many disjoint paths important for understanding a relationship, and the classification is effective for explaining relationships.

  12. Reinforcement Learning Explains Conditional Cooperation and Its Moody Cousin

    PubMed Central

    Ezaki, Takahiro; Horita, Yutaka; Masuda, Naoki

    2016-01-01

    Direct reciprocity, or repeated interaction, is a main mechanism to sustain cooperation under social dilemmas involving two individuals. For larger groups and networks, which are probably more relevant to understanding and engineering our society, experiments employing repeated multiplayer social dilemma games have suggested that humans often show conditional cooperation behavior and its moody variant. Mechanisms underlying these behaviors largely remain unclear. Here we provide a proximate account for this behavior by showing that individuals adopting a type of reinforcement learning, called aspiration learning, phenomenologically behave as conditional cooperator. By definition, individuals are satisfied if and only if the obtained payoff is larger than a fixed aspiration level. They reinforce actions that have resulted in satisfactory outcomes and anti-reinforce those yielding unsatisfactory outcomes. The results obtained in the present study are general in that they explain extant experimental results obtained for both so-called moody and non-moody conditional cooperation, prisoner’s dilemma and public goods games, and well-mixed groups and networks. Different from the previous theory, individuals are assumed to have no access to information about what other individuals are doing such that they cannot explicitly use conditional cooperation rules. In this sense, myopic aspiration learning in which the unconditional propensity of cooperation is modulated in every discrete time step explains conditional behavior of humans. Aspiration learners showing (moody) conditional cooperation obeyed a noisy GRIM-like strategy. This is different from the Pavlov, a reinforcement learning strategy promoting mutual cooperation in two-player situations. PMID:27438888

  13. Reinforcement Learning Explains Conditional Cooperation and Its Moody Cousin.

    PubMed

    Ezaki, Takahiro; Horita, Yutaka; Takezawa, Masanori; Masuda, Naoki

    2016-07-01

    Direct reciprocity, or repeated interaction, is a main mechanism to sustain cooperation under social dilemmas involving two individuals. For larger groups and networks, which are probably more relevant to understanding and engineering our society, experiments employing repeated multiplayer social dilemma games have suggested that humans often show conditional cooperation behavior and its moody variant. Mechanisms underlying these behaviors largely remain unclear. Here we provide a proximate account for this behavior by showing that individuals adopting a type of reinforcement learning, called aspiration learning, phenomenologically behave as conditional cooperator. By definition, individuals are satisfied if and only if the obtained payoff is larger than a fixed aspiration level. They reinforce actions that have resulted in satisfactory outcomes and anti-reinforce those yielding unsatisfactory outcomes. The results obtained in the present study are general in that they explain extant experimental results obtained for both so-called moody and non-moody conditional cooperation, prisoner's dilemma and public goods games, and well-mixed groups and networks. Different from the previous theory, individuals are assumed to have no access to information about what other individuals are doing such that they cannot explicitly use conditional cooperation rules. In this sense, myopic aspiration learning in which the unconditional propensity of cooperation is modulated in every discrete time step explains conditional behavior of humans. Aspiration learners showing (moody) conditional cooperation obeyed a noisy GRIM-like strategy. This is different from the Pavlov, a reinforcement learning strategy promoting mutual cooperation in two-player situations. PMID:27438888

  14. Evidence and Proof: Explaining Vector Relationships.

    ERIC Educational Resources Information Center

    Doerr, Helen M.

    This paper addresses a central issue in secondary school geometry, namely the role of proof. In an integrated mathematics and science curriculum, the role of proof as a process of conjecturing, explaining, and justifying within a small-group setting is analyzed. Particular attention is given to the students' use of empirical evidence and algebraic…

  15. How Employees Remain Happy: Explaining a Paradox

    ERIC Educational Resources Information Center

    Hutton, Dorothy M.; Atkinson, Barbara; Judd, Priya; Darling, Julie; Tran, Linh; Cummins, Robert A.

    2004-01-01

    This paper draws on subjective quality of life theory to explain findings from three studies of quality of work life. The studies were conducted with 346 regional process workers, metropolitan employment officers and nurses. The results support the adoption of the theory of homeostasis as an explanation for findings on subjective wellbeing at work…

  16. Do changes in connectivity explain desertification?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Desertification, broad-scale land degradation in drylands, is a major environmental hazard facing inhabitants of the world’s deserts as well as an important component of global change. There is no unifying framework that simply and effectively explains different forms of desertification. Here we arg...

  17. Explaining High Abilities of Nobel Laureates

    ERIC Educational Resources Information Center

    Shavinina, Larisa

    2004-01-01

    Although the Nobel Prize is associated with a rare, superior degree of intellectually creative achievement, high abilities of Nobel laureates are far from well explained. This paper argues that Nobel laureates' high abilities are determined in part by their extracognitive abilities, that is, specific feelings, preferences, beliefs and intuitive…

  18. Explaining Autism: Its Discursive and Neuroanatomical Characteristics.

    ERIC Educational Resources Information Center

    Oller, John W., Jr.; Rascon, Dana

    This paper reviews the existing empirical research on autism in the context of the semiotic theories of Charles S. Peirce. His ideas of the generalized logic of relations are seen as explaining the unusual associations (or lack thereof) in autism. Concepts of "indices" or signs singling out distinct objects, and "adinity" or the number of distinct…

  19. Heavy fermion behavior explained by bosons

    NASA Technical Reports Server (NTRS)

    Kallio, A.; Poykko, S.; Apaja, V.

    1995-01-01

    Conventional heavy fermion (HF) theories require existence of massive fermions. We show that heavy fermion phenomena can also be simply explained by existence of bosons with moderate mass but temperature dependent concentration below the formation temperature T(sub B), which in turn is close to room temperature. The bosons B(++) are proposed to be in chemical equilibrium with a system of holes h(+): B(++) = h(+) + h(+). This equilibrium is governed by a boson breaking function f(T), which determines the decreasing boson density and the increasing fermion density with increasing temperature. Since HF-compounds are hybridized from minimum two elements, we assume in addition existence of another fermion component h(sub s)(+) with temperature independent density. This spectator component is thought to be the main agent in binding the bosons in analogy with electronic or muonic molecules. Using a linear boson breaking function we can explain temperature dependence of the giant linear specific heat coefficient gamma(T) coming essentially from bosons. The maxima in resistivity, Hall coefficient, and susceptibility are explained by boson localization effects due to the Wigner crystallization. The antiferromagnetic transitions in turn are explained by similar localization of the pairing fermion system when their density n(sub h)(T(sub FL)) becomes lower than n(sub WC), the critical density of Wigner crystallization. The model applies irrespective whether a compound is superconducting or not. The same model explains the occurrence of low temperature antiferromagnetism also in high-T(sub c) superconductors. The double transition in UPt3 is proposed to be due to the transition of the pairing fermion liquid from spin polarized to unpolarized state.

  20. Classic reaction kinetics can explain complex patterns of antibiotic action

    PubMed Central

    zur Wiesch, P. Abel; Abel, S.; Gkotzis, S.; Ocampo, P.; Engelstädter, J.; Hinkley, T.; Magnus, C.; Waldor, M. K.; Udekwu, K.; Cohen, T.

    2015-01-01

    Finding optimal dosing strategies for treating bacterial infections is extremely difficult, and improving therapy requires costly and time-intensive experiments. To date, an incomplete mechanistic understanding of drug effects has limited our ability to make accurate quantitative predictions of drug-mediated bacterial killing and impeded the rational design of antibiotic treatment strategies. Three poorly understood phenomena complicate predictions of antibiotic activity: post-antibiotic growth suppression, density-dependent antibiotic effects, and persister cell formation. Here, we show that chemical binding kinetics alone are sufficient to explain these three phenomena, using single cell data and time-kill curves of Escherichia coli and Vibrio cholerae exposed to a variety of antibiotics in combination with a theoretical model that links chemical reaction kinetics to bacterial population biology. Our model reproduces existing observations, has a high predictive power across different experimental setups (R2= 0.86), and makes several testable predictions, which we verified in new experiments and by analysing published data from a clinical trial on tuberculosis therapy. While a variety of biological mechanisms have previously been invoked to explain post-antibiotic growth suppression, density-dependent antibiotic effects, and especially persister cell formation, our findings reveal that a simple model which considers only binding kinetics provides a parsimonious and unifying explanation for these three complex, phenotypically distinct behaviours. Current antibiotic and other chemotherapeutic regimens are often based on trial-and-error or expert opinion. Our ‘chemical reaction kinetics’-based approach may inform new strategies, that are based on rational design. PMID:25972005

  1. Classic reaction kinetics can explain complex patterns of antibiotic action.

    PubMed

    Abel Zur Wiesch, Pia; Abel, Sören; Gkotzis, Spyridon; Ocampo, Paolo; Engelstädter, Jan; Hinkley, Trevor; Magnus, Carsten; Waldor, Matthew K; Udekwu, Klas; Cohen, Ted

    2015-05-13

    Finding optimal dosing strategies for treating bacterial infections is extremely difficult, and improving therapy requires costly and time-intensive experiments. To date, an incomplete mechanistic understanding of drug effects has limited our ability to make accurate quantitative predictions of drug-mediated bacterial killing and impeded the rational design of antibiotic treatment strategies. Three poorly understood phenomena complicate predictions of antibiotic activity: post-antibiotic growth suppression, density-dependent antibiotic effects, and persister cell formation. We show that chemical binding kinetics alone are sufficient to explain these three phenomena, using single-cell data and time-kill curves of Escherichia coli and Vibrio cholerae exposed to a variety of antibiotics in combination with a theoretical model that links chemical reaction kinetics to bacterial population biology. Our model reproduces existing observations, has a high predictive power across different experimental setups (R(2) = 0.86), and makes several testable predictions, which we verified in new experiments and by analyzing published data from a clinical trial on tuberculosis therapy. Although a variety of biological mechanisms have previously been invoked to explain post-antibiotic growth suppression, density-dependent antibiotic effects, and especially persister cell formation, our findings reveal that a simple model that considers only binding kinetics provides a parsimonious and unifying explanation for these three complex, phenotypically distinct behaviours. Current antibiotic and other chemotherapeutic regimens are often based on trial and error or expert opinion. Our "chemical reaction kinetics"-based approach may inform new strategies, which are based on rational design. PMID:25972005

  2. Explaining Underrepresentation: A Theory of Precluded Interest

    PubMed Central

    Plaut, Victoria C.

    2010-01-01

    What processes best explain women’s underrepresentation in science, math, and engineering fields in the U.S.? Do they also explain men’s underrepresentation in the humanities? Two survey studies across two U.S. West Coast universities (N = 62; N = 614) addressed these questions in the context of two fields: one male-dominated (computer science) and the other female-dominated (English). Among a set of social predictors—including perceived similarity to the people in the field, social identity threats, and expectations of success—the best mediator of women’s lower interest in computer science and men’s lower interest in English was perceived similarity. Thus, changing students’ social perceptions of how they relate to those in the field may help to diversify academic fields. PMID:20930923

  3. ExplainHoudini: Making Houdini Inference Transparent

    NASA Astrophysics Data System (ADS)

    Lahiri, Shuvendu K.; Vanegue, Julien

    Houdini is a simple yet scalable technique for annotation inference for modular contract checking. The input to Houdini is a set of candidate annotations, and the output is a consistent subset of these candidates. Since this technique is most useful as an annotation assistant for user-guided refinement of annotations, understanding the reason for the removal of annotations is crucial for a user to refine the set of annotations, and classify false errors easily. This is especially true for applying Houdini to large legacy modules with thousands of procedures and deep call chains. In this work we present a method ExplainHoudini that explains the reason why a given candidate was removed, purely in terms of the existing candidates. We have implemented this algorithm and provide preliminary experience of applying it on large modules.

  4. Children's Theories and the Drive to Explain

    NASA Astrophysics Data System (ADS)

    Schwitzgebel, Eric

    Debate has been growing in developmental psychology over how much the cognitive development of children is like theory change in science. Useful debate on this topic requires a clear understanding of what it would be for a child to have a theory. I argue that existing accounts of theories within philosophy of science and developmental psychology either are less precise than is ideal for the task or cannot capture everyday theorizing of the sort that children, if they theorize, must do. I then propose an account of theories that ties theories and explanation very closely together, treating theories primarily as products of a drive to explain. I clarify some of the positions people have taken regarding the theory theory of development, and I conclude by proposing that psychologists interested in the ''theory theory'' look for patterns of affect and arousal in development that would accompany the existence of a drive to explain.

  5. Kritiks: The Attitude of the Diet Explained.

    ERIC Educational Resources Information Center

    Berube, David M.

    1996-01-01

    Attempts to define critiques by evaluating working taxonomies and examining the basis for critiques in argumentation theory and practice. Establishes a case for "kritiks" (vs. critiques). Reviews major criticisms of theory and practice strategies for debating them. Concludes that this argument genre should not be rejected prematurely. Draws…

  6. Connecting Representations: Using Predict, Check, Explain

    ERIC Educational Resources Information Center

    Roy, George J.; Fueyo, Vivian; Vahey, Philip; Knudsen, Jennifer; Rafanan, Ken; Lara-Meloy, Teresa

    2016-01-01

    Although educators agree that making connections with the real world, as advocated by "Principles to Actions: Ensuring Mathematical Success for All" (NCTM 2014), is important, making such connections while addressing important mathematics is elusive. The authors have found that math content coupled with the instructional strategy of…

  7. Strategies That Work to Help Prevent Suicides

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_159314.html Strategies That Work to Help Prevent Suicides Measures include ... legislation, has the potential to change public health strategies in suicide prevention plans," Zohar explained. "With these ...

  8. Dissipative dark matter explains rotation curves

    NASA Astrophysics Data System (ADS)

    Foot, R.

    2015-06-01

    Dissipative dark matter, where dark matter particles interact with a massless (or very light) boson, is studied. Such dark matter can arise in simple hidden sector gauge models, including those featuring an unbroken U (1 )' gauge symmetry, leading to a dark photon. Previous work has shown that such models can not only explain the large scale structure and cosmic microwave background, but potentially also dark matter phenomena on small scales, such as the inferred cored structure of dark matter halos. In this picture, dark matter halos of disk galaxies not only cool via dissipative interactions but are also heated via ordinary supernovae (facilitated by an assumed photon-dark photon kinetic mixing interaction). This interaction between the dark matter halo and ordinary baryons, a very special feature of these types of models, plays a critical role in governing the physical properties of the dark matter halo. Here, we further study the implications of this type of dissipative dark matter for disk galaxies. Building on earlier work, we develop a simple formalism which aims to describe the effects of dissipative dark matter in a fairly model independent way. This formalism is then applied to generic disk galaxies. We also consider specific examples, including NGC 1560 and a sample of dwarf galaxies from the LITTLE THINGS survey. We find that dissipative dark matter, as developed here, does a fairly good job accounting for the rotation curves of the galaxies considered. Not only does dissipative dark matter explain the linear rise of the rotational velocity of dwarf galaxies at small radii, but it can also explain the observed wiggles in rotation curves which are known to be correlated with corresponding features in the disk gas distribution.

  9. Deglaciation explains bat extinction in the Caribbean

    PubMed Central

    Dávalos, Liliana M; Russell, Amy L

    2012-01-01

    Ecological factors such as changing climate on land and interspecific competition have been debated as possible causes of postglacial Caribbean extinction. These hypotheses, however, have not been tested against a null model of climate-driven postglacial area loss. Here, we use a new Quaternary mammal database and deep-sea bathymetry to estimate species–area relationships (SARs) at present and during the Last Glacial Maximum (LGM) for bats of the Caribbean, and to model species loss as a function of area loss from rising sea level. Island area was a significant predictor of species richness in the Bahamas, Greater Antilles, and Lesser Antilles at all time periods, except for the Lesser Antilles during the LGM. Parameters of LGM and current SARs were similar in the Bahamas and Greater Antilles, but not the Lesser Antilles, which had fewer estimated species during the LGM than expected given their size. Estimated postglacial species losses in the Bahamas and Greater Antilles were largely explained by inferred area loss from rising sea level in the Holocene. However, there were more species in the Bahamas at present, and fewer species in the smaller Greater Antilles, than expected given island size and the end-Pleistocene/early Holocene SARs. Poor fossil sampling and ecological factors may explain these departures from the null. Our analyses illustrate the importance of changes in area in explaining patterns of species richness through time and emphasize the role of the SAR as a null hypothesis in explorations of the impact of novel ecological interactions on extinction. PMID:23301171

  10. Does information theory explain biological evolution?

    NASA Astrophysics Data System (ADS)

    Battail, G.

    1997-11-01

    It is suggested that Dawkins' model of evolution needs error-correction coding in the genome replication process. Nested coding is moreover assumed. Consequences of these hypotheses are drawn using fundamental results of information theory. Genome replication is dealt with independently of phenotype encoding, which pertains to semantics. The proposed hypotheses enable explaining facts of genetics and evolution, including the existence of redundant DNA (the introns), the observed correlation between the rate of mutations on the one hand, the genome length and the redundancy rate on the other hand, the discreteness of species and the trend of eukaryotes evolution towards complexity.

  11. Life-Saving Space Technology Explained

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Dr. Harry Whelan, a pediatric Neurologist at the Medical Hospital of Wisconsin in Milwaukee and professor of Neurology at the Medical College of Wisconsin, explains the operation of light-emitting diodes (LEDs) developed for use in space plant growth experiments and now adapted for use in photodynamic therapy, a technique in which light from the LEDs activates light-sensitive, tumor-treating drugs. The technique has been used in at least two surgeries on brain tumors. The LED project was one of several NASA exhibits at AirVenture 2000 sponsored by the Experimental Aircraft Association in Oshkosh, WI.

  12. Developing User Strategies in PVS: A Tutorial

    NASA Technical Reports Server (NTRS)

    Archer, Myla; diVito, Ben; Munoz, Cesar

    2003-01-01

    This tutorial provides an overview of the PVS strategy language, and explains how to define new PVS strategies and load them into PVS, and how to create a strategy package. It then discusses several useful techniques that can be used in developing user strategies, and provides examples that illustrate many of these techniques.

  13. Ecology and multilevel selection explain aggression in spider colonies.

    PubMed

    Biernaskie, Jay M; Foster, Kevin R

    2016-08-01

    Progress in sociobiology continues to be hindered by abstract debates over methodology and the relative importance of within-group vs. between-group selection. We need concrete biological examples to ground discussions in empirical data. Recent work argued that the levels of aggression in social spider colonies are explained by group-level adaptation. Here, we examine this conclusion using models that incorporate ecological detail while remaining consistent with kin- and multilevel selection frameworks. We show that although levels of aggression are driven, in part, by between-group selection, incorporating universal within-group competition provides a striking fit to the data that is inconsistent with pure group-level adaptation. Instead, our analyses suggest that aggression is favoured primarily as a selfish strategy to compete for resources, despite causing lower group foraging efficiency or higher risk of group extinction. We argue that sociobiology will benefit from a pluralistic approach and stronger links between ecologically informed models and data. PMID:27264438

  14. Explanations in knowledge systems - Design for Explainable Expert Systems

    NASA Technical Reports Server (NTRS)

    Swartout, William; Paris, Cecile; Moore, Johanna

    1991-01-01

    The Explainable Expert Systems framework (EES), in which the focus is on capturing those design aspects that are important for producing good explanations, including justifications of the system's actions, explications of general problem-solving strategies, and descriptions of the system's terminology, is discussed. EES was developed as part of the Strategic Computing Initiative of DARPA. Both the general principles from which the system was derived and how the system was derived from those principles can be represented in EES. The Program Enhancement Advisor, which is the main prototype on which the explanation work has been developed and tested, is presented. PEA is an advice system that helps users improve their Common Lisp programs by recommending transformations that enhance the user's code. How EES produces better explanations is shown.

  15. Developmental systems theory: what does it explain, and how does it explain it?

    PubMed

    Griffiths, Paul E; Tabery, James

    2013-01-01

    We examine developmental systems theory (DST) with two questions in mind: What does DST explain? How does DST explain it? To answer these questions, we start by reviewing major contributions to the origins of DST: the introduction of the idea of a "developmental system", the idea of probabilistic epigenesis, the attention to the role of information in the developmental system, and finally the explicit identification of a DST. We then consider what DST is not, contrasting it with two approaches that have been foils for DST: behavioral genetics and nativist cognitive psychology. Third, we distill out two core concepts that have defined DSTthroughout its history: epigenesis and developmental dynamics. Finally, we turn to how DST explains, arguing that it explains by elucidating mechanisms. PMID:23834002

  16. Mach bands explained by response normalization.

    PubMed

    Kingdom, Frederick A A

    2014-01-01

    Mach bands are the illusory dark and bright bars seen at the foot and knee of a luminance trapezoid. First demonstrated by Ernst Mach in the latter part of the 19th century, Mach bands are a test bed not only for models of brightness illusions but of spatial vision in general. Up until 50 years ago the dominant explanation of Mach Bands was that they were caused by lateral inhibition among retinal neurons. More recently, the dominant idea has been that Mach bands are a consequence of a visual process that generates a sparse, binary description of the image in terms of "edges" and "bars". Another recent explanation is that Mach bands result from learned expectations about the pattern of light typically found on sharply curved surfaces. In keeping with recent multi-scale filtering accounts of brightness illusions as well as current physiology, I show however that Mach bands are most simply explained by response normalization, whereby the gains of early visual channels are adjusted on a local basis to make their responses more equal. I show that a simple one-dimensional model of response normalization explains the range of conditions under which Mach bands occur, and as importantly, the conditions under which they do not occur. PMID:25408643

  17. Can predictive coding explain repetition suppression?

    PubMed

    Grotheer, Mareike; Kovács, Gyula

    2016-07-01

    While in earlier work various local or bottom-up neural mechanisms were proposed to give rise to repetition suppression (RS), current theories suggest that top-down processes play a role in determining the repetition related reduction of the neural responses. In the current review we summarise those results, which support the role of these top-down processes, concentrating on the Bayesian models of predictive coding (PC). Such models assume that RS is related to the statistical probabilities of prior stimulus occurrences and to the future predictability of these stimuli. Here we review the current results that support or argue against this explanation. We point out that the heterogeneity of experimental manipulations that are thought to reflect predictive processes are likely to measure different processing steps, making their direct comparison difficult. In addition we emphasize the importance of identifying these sub-processes and clarifying their role in explaining RS. Finally, we propose a two-stage model for explaining the relationships of repetition and expectation phenomena in the human cortex. PMID:26861559

  18. Dark Matter and Dark Energy Explained

    NASA Astrophysics Data System (ADS)

    Aisenberg, Sol

    2006-03-01

    The standard model of the universe has many mysteries and defects requiring the use of large fudge factors such as Dark Matter and Dark Energy. We will show that Dark Matter is needed when we try to extend Newton's law of gravity (based upon observations in our solar system) to galactic distances. Dark Matter was introduced to explain the observed flat velocity rotation curves of the outer parts of spiral galaxies, as observed by Vera. Rubin. Much earlier, the (under appreciated) Fritz Zwicky introduced the need for large amounts of missing invisible matter to explain the surprising observed motion of groups of remote galaxies. In our hypothesis, the modification of Newton's laws by the addition of a linear term to the gravitational constant that increases with distance will eliminate the need for dark matter. Our hypothesis is different from the MOND theory of Milgrom, which depends upon acceleration. The Red shift observations by Hubble as a function of distance, and interpreted as ``apparent Doppler effect'' led to the unproven belief that the universe is expanding, and thus to the Big Bang. In turn the apparent acceleration of the expansion required the introduction of Dark Energy. Actually there are three additional components of the red shift that are solely due to gravity and distance and can be larger than the Doppler contribution.

  19. EXPLAINING THE ASSOCIATION BETWEEN INCARCERATION AND DIVORCE*

    PubMed Central

    Siennick, Sonja E.; Stewart, Eric A.; Staff, Jeremy

    2014-01-01

    Recent studies have suggested that incarceration dramatically increases the odds of divorce, but we know little about the mechanisms that explain the association. This study uses prospective longitudinal data from a subset of married young adults in the National Longitudinal Study of Adolescent Health (N = 1,919) to examine whether incarceration is associated with divorce indirectly via low marital love, economic strain, relationship violence, and extramarital sex. The findings confirmed that incarcerations occurring during, but not before, a marriage were associated with an increased hazard of divorce. Incarcerations occurring during marriage also were associated with less marital love, more relationship violence, more economic strain, and greater odds of extramarital sex. Above-average levels of economic strain were visible among respondents observed preincarceration, but only respondents observed postincarceration showed less marital love, more relationship violence, and higher odds of extramarital sex than did respondents who were not incarcerated during marriage. These relationship problems explained approximately 40 percent of the association between incarceration and marital dissolution. These findings are consistent with theoretical predictions that a spouse’s incarceration alters the rewards and costs of the marriage and the relative attractiveness of alternative partners. PMID:25598544

  20. Mach bands explained by response normalization

    PubMed Central

    Kingdom, Frederick A. A.

    2014-01-01

    Mach bands are the illusory dark and bright bars seen at the foot and knee of a luminance trapezoid. First demonstrated by Ernst Mach in the latter part of the 19th century, Mach bands are a test bed not only for models of brightness illusions but of spatial vision in general. Up until 50 years ago the dominant explanation of Mach Bands was that they were caused by lateral inhibition among retinal neurons. More recently, the dominant idea has been that Mach bands are a consequence of a visual process that generates a sparse, binary description of the image in terms of “edges” and “bars”. Another recent explanation is that Mach bands result from learned expectations about the pattern of light typically found on sharply curved surfaces. In keeping with recent multi-scale filtering accounts of brightness illusions as well as current physiology, I show however that Mach bands are most simply explained by response normalization, whereby the gains of early visual channels are adjusted on a local basis to make their responses more equal. I show that a simple one-dimensional model of response normalization explains the range of conditions under which Mach bands occur, and as importantly, the conditions under which they do not occur. PMID:25408643

  1. Effective compliance strategies

    SciTech Connect

    Sikora, V.A.; Harrison, J.

    1981-05-01

    The goal of environmental health programs is to have individuals comply with the program standards and guidelines. There are different roles and may be different views by field personnel and administrators on achieving compliance. The compliance strategies of standards enforcement, licenses, permits, approvals, administrative process, orders, rules, quasi-public records, and civil penalties are explained and discussed.

  2. Explaining the gender difference in nightmare frequency.

    PubMed

    Schredl, Michael

    2014-01-01

    A recent meta-analysis showed a robust gender difference in nightmare frequency of medium effect size in adolescents and young adults: Women tend to report nightmares more frequently than men. The present study, carried out in an unselected student sample, indicates that 2 factors mediate the gender difference in nightmare frequency: neuroticism and overall dream recall frequency. The effect of neuroticism on the gender difference and the finding that the gender difference in nightmare frequency emerges at an age of about 10 years suggest that gender-specific socialization processes may play an important role in explaining the gender differences in nightmare frequency in adolescents and young to middle-aged adults. This idea is supported by the previous finding that nightmare frequency is related to sex role orientation. However, longitudinal studies are necessary to validate these hypotheses. PMID:24934011

  3. Bell Test experiments explained without entanglement

    NASA Astrophysics Data System (ADS)

    Boyd, Jeffrey

    2011-04-01

    by Jeffrey H. Boyd. Jeffreyhboyd@gmail.com. John Bell proposed a test of what was called "local realism." However that is a different view of reality than we hold. Bell incorrectly assumed the validity of wave particle dualism. According to our model waves are independent of particles; wave interference precedes the emission of a particle. This results in two conclusions. First the proposed inequalities that apply to "local realism" in Bell's theorem do not apply to this model. The alleged mathematics of "local realism" is therefore wrong. Second, we can explain the Bell Test experimental results (such as the experiments done at Innsbruck) without any need for entanglement, non-locality, or particle superposition.

  4. Explaining math: gesturing lightens the load.

    PubMed

    Goldin-Meadow, S; Nusbaum, H; Kelly, S D; Wagner, S

    2001-11-01

    Why is it that people cannot keep their hands still when they talk? One reason may be that gesturing actually lightens cognitive load while a person is thinking of what to say. We asked adults and children to remember a list of letters or words while explaining how they solved a math problem. Both groups remembered significantly more items when they gestured during their math explanations than when they did not gesture. Gesturing appeared to save the speakers' cognitive resources on the explanation task, permitting the speakers to allocate more resources to the memory task. It is widely accepted that gesturing reflects a speaker's cognitive state, but our observations suggest that, by reducing cognitive load, gesturing may also play a role in shaping that state. PMID:11760141

  5. Weaker dental enamel explains dental decay.

    PubMed

    Vieira, Alexandre R; Gibson, Carolyn W; Deeley, Kathleen; Xue, Hui; Li, Yong

    2015-01-01

    Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is "weaker" while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution. PMID:25885796

  6. Explaining Today's Physics Through History and Biography

    NASA Astrophysics Data System (ADS)

    Lindley, David

    2014-03-01

    Quantum computers, string theory, holographic universes - to the general audience, today's physics can be as mystifying as it is fascinating. But modern ideas evolved from an earlier phase of physics - Newtonian mechanics, simple cause and effect - that is in principle easier for the non-expert to grasp. I have found that writing about physics from a historical and biographical perspective is an effective way to convey modern thinking by explaining where it comes from - it is a way of carrying the reader from concepts that make intuitive sense to ideas that seem, on first encounter, utterly bizarre. Smuggling explanations into stories satisfies the reader's desire for narrative - bearing in mind that narrative can include the evolution of ideas as well as tales about intriguing and original people.

  7. Macromolecular crowding explains overflow metabolism in cells

    PubMed Central

    Vazquez, Alexei; Oltvai, Zoltán N.

    2016-01-01

    Overflow metabolism is a metabolic phenotype of cells characterized by mixed oxidative phosphorylation (OxPhos) and fermentative glycolysis in the presence of oxygen. Recently, it was proposed that a combination of a protein allocation constraint and a higher proteome fraction cost of energy generation by OxPhos relative to fermentation form the basis of overflow metabolism in the bacterium, Escherichia coli. However, we argue that the existence of a maximum or optimal macromolecular density is another essential requirement. Here we re-evaluate our previous theory of overflow metabolism based on molecular crowding following the proteomic fractions formulation. We show that molecular crowding is a key factor in explaining the switch from OxPhos to overflow metabolism. PMID:27484619

  8. Transitioning from Idiopathic to Explainable Autoimmune Hepatitis.

    PubMed

    Czaja, Albert J

    2015-10-01

    Autoimmune hepatitis lacks an identifiable cause, and its diagnosis requires the exclusion of etiologically defined diseases that resemble it. Insights into its pathogenesis are moving autoimmune hepatitis from an idiopathic to explainable disease, and the goal of this review is to describe the insights that are hastening this transition. Two types of autoimmune hepatitis are justified by serological markers, but they also have distinctive genetic associations (DRB1 and DQB1 genes) and autoantigens. DRB1 alleles are the principal susceptibility factors in white adults, and a six amino acid sequence encoded in the antigen-binding groove of class II molecules of the major histocompatibility complex can influence the selection of autoantigens. Polymorphisms, including variants of SH2B3 and CARD10 genes, may affect immune reactivity and disease severity. The cytochrome mono-oxygenase, CYP2D6, is the autoantigen associated with type 2 autoimmune hepatitis, and it shares homologies with multiple viruses that might promote self-intolerance by molecular mimicry. Chemokines, especially CXCL9 and CXCL10, orchestrate the migration of effector cells to sites of injury and are associated with disease severity. Cells of the innate and adaptive immune responses promote tissue damage, and possible deficiencies in the number and function of regulatory T cells may facilitate the injurious process. Receptor-mediated apoptosis is the principal mechanism of hepatocyte loss, and cell-mediated and antibody-dependent mechanisms of cytotoxicity also contribute. Insights that explain autoimmune hepatitis will allow triggering exogenous antigens to be characterized, risk management to be improved, prognostic indices to be refined, and site-specific therapeutic interventions to emerge. PMID:25999246

  9. Explaining Polarization Reversals in STEREO Wave Data

    NASA Technical Reports Server (NTRS)

    Breneman, A.; Cattell, C.; Wygant, J.; Kersten, K.; Wilson, L, B., III; Dai, L.; Colpitts, C.; Kellogg, P. J.; Goetz, K.; Paradise, A.

    2012-01-01

    Recently Breneman et al. reported observations of large amplitude lightning and transmitter whistler mode waves from two STEREO passes through the inner radiation belt (L<2). Hodograms of the electric field in the plane transverse to the magnetic field showed that the transmitter waves underwent periodic polarization reversals. Specifically, their polarization would cycle through a pattern of right-hand to linear to left-hand polarization at a rate of roughly 200 Hz. The lightning whistlers were observed to be left-hand polarized at frequencies greater than the lower hybrid frequency and less than the transmitter frequency (21.4 kHz) and right-hand polarized otherwise. Only righthand polarized waves in the inner radiation belt should exist in the frequency range of the whistler mode and these reversals were not explained in the previous paper. We show, with a combination of observations and simulated wave superposition, that these polarization reversals are due to the beating of an incident electromagnetic whistler mode wave at 21.4 kHz and linearly polarized, symmetric lower hybrid sidebands Doppler-shifted from the incident wave by +/-200 Hz. The existence of the lower hybrid waves is consistent with the parametric decay mechanism of Lee and Kuo whereby an incident whistler mode wave decays into symmetric, short wavelength lower hybrid waves and a purely growing (zero-frequency) mode. Like the lower hybrid waves, the purely growing mode is Doppler-shifted by 200 Hz as observed on STEREO. This decay mechanism in the upper ionosphere has been previously reported at equatorial latitudes and is thought to have a direct connection with explosive spread F enhancements. As such it may represent another dissipation mechanism of VLF wave energy in the ionosphere and may help to explain a deficit of observed lightning and transmitter energy in the inner radiation belts as reported by Starks et al.

  10. Young Australian women explain their contraceptive choices.

    PubMed

    Wigginton, Britta; Moran, Claire; Harris, Melissa L; Loxton, Deborah; Lucke, Jayne

    2016-07-01

    New developments in female contraceptives allow women increased options for preventing pregnancy, while men's options for reversible contraception have not advanced beyond the condom. There has been little discursive exploration of how neoliberal and postfeminist discourses shape women's accounts of choosing whether or not to use contraception. Our thematic discourse analysis of 760 free-text responses to a question about contraceptive choice considers the social and political climate that promotes the self-governed woman who freely chooses contraception. We examine the ways in which women formulated and defended their accounts of choice, focusing on the theme of free contraceptive choice that constructed women's choices as unconstrained by material, social and political forces. We identify two discursive strategies that underpinned this theme: a woman's body, a woman's choice and planning parenthood, and explore the ways in which choice was understood as a gendered entitlement and how contraceptive choices were shaped (and constrained) by women's plans for parenthood. We discuss the implications of these discursive strategies, and neoliberal and postfeminist discourses, in terms of the disallowance of any contextual, social and structural factors, including the absence of men in the 'contraceptive economy'. PMID:26670866

  11. Explaining evolution via constrained persistent perfect phylogeny

    PubMed Central

    2014-01-01

    Background The perfect phylogeny is an often used model in phylogenetics since it provides an efficient basic procedure for representing the evolution of genomic binary characters in several frameworks, such as for example in haplotype inference. The model, which is conceptually the simplest, is based on the infinite sites assumption, that is no character can mutate more than once in the whole tree. A main open problem regarding the model is finding generalizations that retain the computational tractability of the original model but are more flexible in modeling biological data when the infinite site assumption is violated because of e.g. back mutations. A special case of back mutations that has been considered in the study of the evolution of protein domains (where a domain is acquired and then lost) is persistency, that is the fact that a character is allowed to return back to the ancestral state. In this model characters can be gained and lost at most once. In this paper we consider the computational problem of explaining binary data by the Persistent Perfect Phylogeny model (referred as PPP) and for this purpose we investigate the problem of reconstructing an evolution where some constraints are imposed on the paths of the tree. Results We define a natural generalization of the PPP problem obtained by requiring that for some pairs (character, species), neither the species nor any of its ancestors can have the character. In other words, some characters cannot be persistent for some species. This new problem is called Constrained PPP (CPPP). Based on a graph formulation of the CPPP problem, we are able to provide a polynomial time solution for the CPPP problem for matrices whose conflict graph has no edges. Using this result, we develop a parameterized algorithm for solving the CPPP problem where the parameter is the number of characters. Conclusions A preliminary experimental analysis shows that the constrained persistent perfect phylogeny model allows to

  12. Applying a Predict-Observe-Explain Sequence in Teaching of Buoyant Force

    ERIC Educational Resources Information Center

    Radovanovic, Jelena; Slisko, Josip

    2013-01-01

    An active learning sequence based on the predict-observe-explain teaching strategy is applied to a lesson on buoyant force. The results obtained clearly justify the use of this teaching method and suggest devising a series of activities to enable more effective removal of students' commonly held alternative conceptions regarding floating and…

  13. Ocean currents help explain population genetic structure

    PubMed Central

    White, Crow; Selkoe, Kimberly A.; Watson, James; Siegel, David A.; Zacherl, Danielle C.; Toonen, Robert J.

    2010-01-01

    Management and conservation can be greatly informed by considering explicitly how environmental factors influence population genetic structure. Using simulated larval dispersal estimates based on ocean current observations, we demonstrate how explicit consideration of frequency of exchange of larvae among sites via ocean advection can fundamentally change the interpretation of empirical population genetic structuring as compared with conventional spatial genetic analyses. Both frequency of larval exchange and empirical genetic difference were uncorrelated with Euclidean distance between sites. When transformed into relative oceanographic distances and integrated into a genetic isolation-by-distance framework, however, the frequency of larval exchange explained nearly 50 per cent of the variance in empirical genetic differences among sites over scales of tens of kilometres. Explanatory power was strongest when we considered effects of multiple generations of larval dispersal via intermediary locations on the long-term probability of exchange between sites. Our results uncover meaningful spatial patterning to population genetic structuring that corresponds with ocean circulation. This study advances our ability to interpret population structure from complex genetic data characteristic of high gene flow species, validates recent advances in oceanographic approaches for assessing larval dispersal and represents a novel approach to characterize population connectivity at small spatial scales germane to conservation and fisheries management. PMID:20133354

  14. Explaining numeracy development in weak performing kindergartners.

    PubMed

    Toll, Sylke W M; Van Luit, Johannes E H

    2014-08-01

    Gaining better insight into precursors of early numeracy in young children is important, especially in those with inadequate numeracy skills. Therefore, in the current study, visual and verbal working memory, non-symbolic and symbolic comparison skills, and specific math-related language were used to explain early numeracy performance and development of weak performing children throughout kindergarten. The early numeracy ability of both weak performers and typical performers was measured at four time points during 2 years of kindergarten to compare growth rates. Results show a significant faster development of early numeracy in the weak performers. The development of weak performers' numeracy was influenced by verbal working memory, symbolic comparison skills, and math language, whereas only math language was positively related to the slope of typical performers' numeracy. In the weak performers, visual working memory, non-symbolic comparison skills, and math language showed an effect on the initial early numeracy level of these children. The intercept of the typical performers was predicted by five covariates, all except non-symbolic comparison. PMID:24786672

  15. Explaining the Cambrian "Explosion" of Animals

    NASA Astrophysics Data System (ADS)

    Marshall, Charles R.

    2006-05-01

    The Cambrian "explosion" is a unique episode in Earth history, when essentially all the animal phyla first appear in the fossil record. A variety of environmental, developmental (genetic), and ecological explanations for this complex and somewhat protracted event are reviewed, with a focus on how well each explains the observed increases in disparity and diversity, the time of onset of the radiation, its duration, and its uniqueness. The increase in disparity (the origin of the phyla) and diversity are best understood as being the result of the interplay of the combinatorial bilaterian developmental system and the increase in the number of needs the first bilaterians had to meet as complex ecological interactions developed. The time of onset is constrained by the evolution of the environment, whereas its duration appears to be controlled primarily by rates of developmental innovation. The uniqueness of the event is either due to ensuing developmental limitation, to ecological saturation, or simply to the exhaustion of ecologically viable morphologies that could be produced by the nascent bilaterian developmental system.

  16. Can Thermal Nonequilibrium Explain Coronal Loops?

    NASA Technical Reports Server (NTRS)

    Klimchuk, James A.; Karpen, Judy T.; Antiochos, Spiro K.

    2010-01-01

    Any successful model of coronal loops must explain a number of observed properties. For warm (approx. 1 MK) loops, these include: 1. excess density, 2. flat temperature profile, 3. super-hydrostatic scale height, 4. unstructured intensity profile, and 5. 1000-5000 s lifetime. We examine whether thermal nonequilibrium can reproduce the observations by performing hydrodynamic simulations based on steady coronal heating that decreases exponentially with height. We consider both monolithic and multi-stranded loops. The simulations successfully reproduce certain aspects of the observations, including the excess density, but each of them fails in at least one critical way. -Xonolithic models have far too much intensity structure, while multi-strand models are either too structured or too long-lived. Storms of nanoflares remain the only viable explanation for warm loops that has been proposed so far. Our results appear to rule out the widespread existence of heating that is both highly concentrated low in the corona and steady or quasi-steady (slowly varying or impulsive with a rapid cadence). Active regions would have a very different appearance if the dominant heating mechanism had these properties. Thermal nonequilibrium may nonetheless play an important role in prominences and catastrophic cooling e(veen.gts..,coronal rain) that occupy a small fraction of the coronal volume. However, apparent inconsistencies between the models and observations of cooling events have yet to be understood.

  17. CAN THERMAL NONEQUILIBRIUM EXPLAIN CORONAL LOOPS?

    SciTech Connect

    Klimchuk, James A.; Karpen, Judy T.; Antiochos, Spiro K.

    2010-05-10

    Any successful model of coronal loops must explain a number of observed properties. For warm ({approx}1 MK) loops, these include (1) excess density, (2) flat temperature profile, (3) super-hydrostatic scale height, (4) unstructured intensity profile, and (5) 1000-5000 s lifetime. We examine whether thermal nonequilibrium can reproduce the observations by performing hydrodynamic simulations based on steady coronal heating that decreases exponentially with height. We consider both monolithic and multi-stranded loops. The simulations successfully reproduce certain aspects of the observations, including the excess density, but each of them fails in at least one critical way. Monolithic models have far too much intensity structure, while multi-strand models are either too structured or too long-lived. Our results appear to rule out the widespread existence of heating that is both highly concentrated low in the corona and steady or quasi-steady (slowly varying or impulsive with a rapid cadence). Active regions would have a very different appearance if the dominant heating mechanism had these properties. Thermal nonequilibrium may nonetheless play an important role in prominences and catastrophic cooling events (e.g., coronal rain) that occupy a small fraction of the coronal volume. However, apparent inconsistencies between the models and observations of cooling events have yet to be understood.

  18. Birdsong dialect patterns explained using magnetic domains

    NASA Astrophysics Data System (ADS)

    Burridge, James; Kenney, Steven

    2016-06-01

    The songs and calls of many bird species, like human speech, form distinct regional dialects. We suggest that the process of dialect formation is analogous to the physical process of magnetic domain formation. We take the coastal breeding grounds of the Puget Sound white crowned sparrow as an example. Previous field studies suggest that birds of this species learn multiple songs early in life, and when establishing a territory for the first time, retain one of these dialects in order to match the majority of their neighbors. We introduce a simple lattice model of the process, showing that this matching behavior can produce single dialect domains provided the death rate of adult birds is sufficiently low. We relate death rate to thermodynamic temperature in magnetic materials, and calculate the critical death rate by analogy with the Ising model. Using parameters consistent with the known behavior of these birds we show that coastal dialect domain shapes may be explained by viewing them as low-temperature "stripe states."

  19. Birdsong dialect patterns explained using magnetic domains.

    PubMed

    Burridge, James; Kenney, Steven

    2016-06-01

    The songs and calls of many bird species, like human speech, form distinct regional dialects. We suggest that the process of dialect formation is analogous to the physical process of magnetic domain formation. We take the coastal breeding grounds of the Puget Sound white crowned sparrow as an example. Previous field studies suggest that birds of this species learn multiple songs early in life, and when establishing a territory for the first time, retain one of these dialects in order to match the majority of their neighbors. We introduce a simple lattice model of the process, showing that this matching behavior can produce single dialect domains provided the death rate of adult birds is sufficiently low. We relate death rate to thermodynamic temperature in magnetic materials, and calculate the critical death rate by analogy with the Ising model. Using parameters consistent with the known behavior of these birds we show that coastal dialect domain shapes may be explained by viewing them as low-temperature "stripe states." PMID:27415293

  20. Punishments and Prizes for Explaining Global Warming

    NASA Astrophysics Data System (ADS)

    Somerville, R. C.

    2006-12-01

    Some few gifted scientists, the late Carl Sagan being an iconic example, are superbly skilled at communicating science clearly and compellingly to non-scientists. Most scientists, however, have serious shortcomings as communicators. The common failings include being verbose, addicted to jargon, caveat- obsessed and focused on details. In addition, it is far easier for a scientist to scoff at the scientific illiteracy of modern society than to work at understanding the viewpoints and concerns of journalists, policymakers and the public. Obstacles await even those scientists with the desire and the talent to communicate science well. Peer pressure and career disincentives can act as powerful deterrents, discouraging especially younger scientists from spending time on non-traditional activities. Scientists often lack mentors and role models to help them develop skills in science communication. Journalists also face real difficulties in getting science stories approved by editors and other gatekeepers. Climate change science brings its own problems in communication. The science itself is unusually wide- ranging and complex. The contentious policies and politics of dealing with global warming are difficult to disentangle from the science. Misinformation and disinformation about climate change are widespread. Intimidation and censorship of scientists by some employers is a serious problem. Polls show that global warming ranks low on the public's list of important issues. Despite all the obstacles, communicating climate change science well is critically important today. It is an art that can be learned and that brings its own rewards and satisfactions. Academic institutions and research funding agencies increasingly value outreach by scientists, and they provide resources to facilitate it. Society needs scientists who can clearly and authoritatively explain the science of global warming and its implications, while remaining objective and policy-neutral. This need will

  1. CARES Helps Explain Secondary Organic Aerosols

    ScienceCinema

    Zaveri, Rahul

    2014-06-02

    What happens when urban man-made pollution mixes with what we think of as pristine forest air? To know more about what this interaction means for the climate, the Carbonaceous Aerosol and Radiative Effects Study, or CARES, field campaign was designed in 2010. The sampling strategy during CARES was coordinated with CalNex 2010, another major field campaign that was planned in California in 2010 by the California Air Resources Board (CARB), the National Oceanic and Atmospheric Administration (NOAA), and the California Energy Commission (CEC). "We found two things. When urban pollution mixes with forest pollutions we get more secondary organic aerosols," said Rahul Zaveri, FCSD scientist and project lead on CARES. "SOAs are thought to be formed primarily from forest emissions but only when they interact with urban emissions. The data is saying that there will be climate cooling over the central California valley because of these interactions." Knowledge gained from detailed analyses of data gathered during the CARES campaign, together with laboratory experiments, is being used to improve existing climate models.

  2. CARES Helps Explain Secondary Organic Aerosols

    SciTech Connect

    Zaveri, Rahul

    2014-03-28

    What happens when urban man-made pollution mixes with what we think of as pristine forest air? To know more about what this interaction means for the climate, the Carbonaceous Aerosol and Radiative Effects Study, or CARES, field campaign was designed in 2010. The sampling strategy during CARES was coordinated with CalNex 2010, another major field campaign that was planned in California in 2010 by the California Air Resources Board (CARB), the National Oceanic and Atmospheric Administration (NOAA), and the California Energy Commission (CEC). "We found two things. When urban pollution mixes with forest pollutions we get more secondary organic aerosols," said Rahul Zaveri, FCSD scientist and project lead on CARES. "SOAs are thought to be formed primarily from forest emissions but only when they interact with urban emissions. The data is saying that there will be climate cooling over the central California valley because of these interactions." Knowledge gained from detailed analyses of data gathered during the CARES campaign, together with laboratory experiments, is being used to improve existing climate models.

  3. CAN PLANETARY INSTABILITY EXPLAIN THE KEPLER DICHOTOMY?

    SciTech Connect

    Johansen, Anders; Davies, Melvyn B.; Church, Ross P.; Holmelin, Viktor

    2012-10-10

    The planet candidates discovered by the Kepler mission provide a rich sample to constrain the architectures and relative inclinations of planetary systems within approximately 0.5 AU of their host stars. We use the triple-transit systems from the Kepler 16 months data as templates for physical triple-planet systems and perform synthetic transit observations, varying the internal inclination variation of the orbits. We find that all the Kepler triple-transit and double-transit systems can be produced from the triple-planet templates, given a low mutual inclination of around 5 Degree-Sign . Our analysis shows that the Kepler data contain a population of planets larger than four Earth radii in single-transit systems that cannot arise from the triple-planet templates. We explore the hypothesis that high-mass counterparts of the triple-transit systems underwent dynamical instability to produce a population of massive double-planet systems of moderately high mutual inclination. We perform N-body simulations of mass-boosted triple-planet systems and observe how the systems heat up and lose planets by planet-planet collisions, and less frequently by ejections or collisions with the star, yielding transits in agreement with the large planets in the Kepler single-transit systems. The resulting population of massive double-planet systems nevertheless cannot explain the additional excess of low-mass planets among the observed single-transit systems and the lack of gas-giant planets in double-transit and triple-transit systems. Planetary instability of systems of triple gas-giant planets can be behind part of the dichotomy between systems hosting one or more small planets and those hosting a single giant planet. The main part of the dichotomy, however, is more likely to have arisen already during planet formation when the formation, migration, or scattering of a massive planet, triggered above a threshold metallicity, suppressed the formation of other planets in sub-AU orbits.

  4. Explaining the Paleoproterozoic Rise of O2

    NASA Astrophysics Data System (ADS)

    Anbar, A. D.; Rye, R.; Kaufman, A. J.

    2001-12-01

    The Paleoproterozoic rise of atmospheric O2 is not understood. Geochemical evidence indicates pO2 \\leq 5 x 10-4 atm before ~ 2.2 Ga and >= 0.03 atm by 2.0 Ga [1]. Most models of this rapid oxygenation account for the timing in an ad hoc manner. In contrast, we suggest oxygenation was driven by rising solar luminosity, a hypothesis consistent with emerging geochemical evidence. Solar luminosity was { ~} 80 % of present value 2.75 Ga. Climate models indicate that pCO2 > 0.2 atm was required before 2.75 Ga if CO2 alone accounted for greenhouse enhancement that averted global glaciation [2]. Paleosols reveal pCO2 <= 10-1.4 atm between 2.75 and 2.2 Ga [3]. This constraint may extend earlier [4]. Given insufficient CO2, CH4 likely helped maintain surface temperature. pCH4 > 10-4 atm would have been adequate 2.75 Ga; Methanogens could sustain this level as long as pO2 was negligible [5]. Atmospheric CH4 and O2 are incompatible. If CH4 was a critical greenhouse gas, increases in pO2 caused global cooling. Temperature and photosynthetic O2 production are probably positively correlated between 273 and 300 K. Combined, these effects constituted a negative feedback on pO2: Excess O2 production cooled the surface, decreasing O2 production until pCH4 was restored. Methanogenesis was decoupled from this feedback as the bulk of Archean methanogens presumably lived in the deep ocean, insulated from surface temperature. Hence, the CH4 greenhouse acted as a cap on pO2 in the Archean. This cap would have eased as rising solar luminosity permitted "titration" of CH4 by increased O2 production; pO2 increased slowly as pCH4 decreased. This feedback suppressed pO2 until solar luminosity allowed the CO2-H2O greenhouse to maintain equable temperatures without appreciable CH4. This threshold was crossed { ~} 2.5 to 2.0 Ga [2], explaining Paleoproterozoic oxygenation. As Earth approached the threshold the CH4 buffer shrank and the likelihood of the feedback being temporarily overwhelmed by

  5. Drastic growth effect may explain sympatric cannibalistic polymorphism.

    PubMed

    Wakano, Joe Yuichiro

    2004-01-01

    Cannibalistic polyphenism is observed in many fishes and amphibians. In the case of amphibian larvae, cannibal morph and typical morph coexist. Benefits and costs of the cannibal morph have been studied empirically but the mechanism of the maintenance of polymorphism is not well known. Here, we construct a game model of typical and cannibal morph strategies to obtain the condition of stable coexistence. Generally, once an individual succeeds in cannibalism, it grows very quickly, which facilitates the next cannibalism. In a model without this 'drastic growth effect', stable coexistence cannot occur. To represent drastic growth effect, it is assumed that cannibal/typical morph stage is followed by giant/normal stage. A cannibal morph that performs cannibalism in the first stage can become a 'giant' in the next stage. This model allows stable coexistence of cannibal and typical morphs. The condition for coexistence is that payoff of a giant is two times larger than normal individuals. As long as direct consumption of victim's body is considered as reward for successful cannibalism, coexistence cannot be explained. When the reward is considered as social standing of being outstanding size in a population, sympatric cannibalistic polymorphism is possible, without regard to the initial size variation or resource shortage. PMID:14637056

  6. Fatal attraction: Explaining Russia's sensitive nuclear transfers to Iran

    NASA Astrophysics Data System (ADS)

    Kuchinsky, Leah R.

    This paper explores Russia's sensitive nuclear assistance to Iran in an effort to determine why a supplier state might proliferate against its own apparent security interests. The goal is to help readers understand the supply-side dynamics of nuclear proliferation. Through careful reconstruction of the historical narrative, using open source data, this study tests the plausibility of a "fatalistic calculus" explanation, identified by Stephen Sestanovich as a possible driver for Russia's behavior. According to the hypothesis, Russia has cooperated with Iran as a way both to stay in the good graces of a neighbor that is suspected of developing nuclear weapons and to win short-term influence and profits. The paper also examines the role of other factors advanced in the existing supply-side literature, such as economic motives identified by physicist and nonproliferation scholar David Albright. The findings show that bureaucratic, economic and fatalistic factors have each played a role in motivating Russia's cooperation with Iran, with their relative importance shifting over time. Fatalism begets a strategy of Russian "minimaxing," in the lexicon of Russia scholar Robert Freedman, wherein Russia attempts to minimize damage to its relationship with the U.S. while maximizing influence in Iran via nuclear cooperation. Fatalism, as actualized by minimaxing, best explains Russia's behavior after former Russian president Vladmir Putin came to power, when the bureaucratic and economic arguments become less cogent.

  7. Incorporating coping into an expectancy framework for explaining drinking behaviour.

    PubMed

    Hasking, Penelope A; Oei, Tian P S

    2008-01-01

    Expectancy Theory has offered much in the way of understanding alcohol use and abuse, and has contributed greatly to prevention and treatment initiatives. However although many cognitive-behavioural treatment approaches are based on expectancy constructs, such as outcome expectancies and self-efficacy, high relapse rates imply that expectancy theory may be too narrow in scope, and that additional variables need to be examined if a comprehensive understanding of drinking behaviour, and better treatment outcomes, are to be achieved. We suggest that the coping strategies an individual employs present one such set of variables that have largely been neglected from an expectancy framework. Although coping skills training is routinely used in prevention and treatment of alcohol problems, coping research has suffered from a poor theoretical framework. In this paper we review the existing research relating expectancies, self-efficacy and coping to drinking behaviour and propose a model which explains both social and dependent drinking, by incorporating coping into an expectancy theory framework. We also outline research and clinical implications of the proposed model. PMID:19630702

  8. Strategy as simple rules.

    PubMed

    Eisenhardt, K M; Sull, D N

    2001-01-01

    The success of Yahoo!, eBay, Enron, and other companies that have become adept at morphing to meet the demands of changing markets can't be explained using traditional thinking about competitive strategy. These companies have succeeded by pursuing constantly evolving strategies in market spaces that were considered unattractive according to traditional measures. In this article--the third in an HBR series by Kathleen Eisenhardt and Donald Sull on strategy in the new economy--the authors ask, what are the sources of competitive advantage in high-velocity markets? The secret, they say, is strategy as simple rules. The companies know that the greatest opportunities for competitive advantage lie in market confusion, but they recognize the need for a few crucial strategic processes and a few simple rules. In traditional strategy, advantage comes from exploiting resources or stable market positions. In strategy as simple rules, advantage comes from successfully seizing fleeting opportunities. Key strategic processes, such as product innovation, partnering, or spinout creation, place the company where the flow of opportunities is greatest. Simple rules then provide the guidelines within which managers can pursue such opportunities. Simple rules, which grow out of experience, fall into five broad categories: how- to rules, boundary conditions, priority rules, timing rules, and exit rules. Companies with simple-rules strategies must follow the rules religiously and avoid the temptation to change them too frequently. A consistent strategy helps managers sort through opportunities and gain short-term advantage by exploiting the attractive ones. In stable markets, managers rely on complicated strategies built on detailed predictions of the future. But when business is complicated, strategy should be simple. PMID:11189455

  9. Learning from Explaining: Does It Matter if Mom Is Listening?

    ERIC Educational Resources Information Center

    Rittle-Johnson, B.; Saylor, M.; Swygert, K.E.

    2008-01-01

    The goal of the current study was to examine whether explaining to another person improves learning and transfer. In the study, 4- and 5-year-olds (N=54) solved multiple classification problems, received accuracy feedback, and were prompted to explain the correct solutions to their moms, to explain the correct solutions to themselves, or to repeat…

  10. Can Differences in Learning Strategies Explain the Benefits of Learning from Static and Dynamic Visualizations?

    ERIC Educational Resources Information Center

    Kuhl, Tim; Scheiter, Katharina; Gerjets, Peter; Gemballa, Sven

    2011-01-01

    The effects of dynamic and static visualizations in understanding physical principles of fish locomotion were investigated. Seventy-five students were assigned to one of three conditions: a text-only, a text with dynamic visualizations, or a text with static visualizations condition. During learning, subjects were asked to think aloud. Learning…

  11. Children's Weighting Strategies for Word-Final Stop Voicing Are Not Explained by Auditory Sensitivities

    ERIC Educational Resources Information Center

    Nittrouer, Susan; Lowenstein, Joanna H.

    2007-01-01

    Purpose: It has been reported that children and adults weight differently the various acoustic properties of the speech signal that support phonetic decisions. This finding is generally attributed to the fact that the amount of weight assigned to various acoustic properties by adults varies across languages, and that children have not yet…

  12. ``Physics with a Smile''-Explaining Phenomena with a Qualitative Problem-Solving Strategy

    NASA Astrophysics Data System (ADS)

    Mualem, Roni; Eylon, Bat-Sheva

    2007-03-01

    Various studies indicate that high school physics students and even college students majoring in physics have difficulties in qualitative understanding of basic concepts and principles of physics.1-5 For example, studies carried out with the Force Concept Inventory (FCI)1,6 illustrate that qualitative tasks are not easy to solve even at the college level. Consequently, "conceptual physics" courses have been designed to foster qualitative understanding, and advanced high school physics courses as well as introductory college-level courses strive to develop qualitative understanding. Many physics education researchers emphasize the importance of acquiring some qualitative understanding of basic concepts in physics as early as middle school or in the context of courses that offer "Physics First" in the ninth grade before biology or chemistry.7 This trend is consistent with the call to focus the science curriculum on a small number of basic concepts and ideas, and to instruct students in a more "meaningful way" leading to better understanding. Studies7-10 suggest that familiar everyday contexts (see Fig. 1) are useful in fostering qualitative understanding.

  13. Typical Farmers: The Strategy Galjart Did Not Explain [and] Article Review.

    ERIC Educational Resources Information Center

    Protas, J. F. da Silva; And Others

    1996-01-01

    Protas and de Andrade state that rural extension efforts in developing nations should not expect the participation of "progressive" farmers to lead to larger participation of other farmers in adopting innovations. Van den Bar offers comments on the article. (SK)

  14. "Physics with a Smile"--Explaining Phenomena with a Qualitative Problem-Solving Strategy

    ERIC Educational Resources Information Center

    Mualem, Roni; Eylon, Bat-Sheva

    2007-01-01

    Various studies indicate that high school physics students and even college students majoring in physics have difficulties in qualitative understanding of basic concepts and principles of physics. For example, studies carried out with the Force Concept Inventory (FCI) illustrate that qualitative tasks are not easy to solve even at the college…

  15. The Failure of Education for All as Political Strategy

    ERIC Educational Resources Information Center

    Heyneman, Stephen P.

    2009-01-01

    Since 1990 the education development community has focused on a strategy titled: Education for All. This article argues that, as political strategy, it has been a failure. The article explains why and suggests ways to correct the problem.

  16. Modeling Secondary Instructional Strategies in a Teacher Education Class

    ERIC Educational Resources Information Center

    Watson, Sandy White; Bradley, Janetta Fleming

    2009-01-01

    In most teacher education courses, instructional strategies are merely listed and explained. Students rarely have the opportunity to see these strategies in use until they become student teachers. What better way to teach secondary instructional strategies to pre-service teachers than by modeling these strategies using teacher education content?…

  17. OBIS: Outdoor Biology Instructional Strategies.

    ERIC Educational Resources Information Center

    Donovan, Edward P.; Richmond, Robert F.

    The Outdoor Biology Instructional Strategies (OBIS) project began in 1972 to enable non-school youth groups (aged 10-15) to gain firsthand experiences in outdoor environments. This descriptive paper explains the program including its purpose and historical background. Specific objectives are to: (1) stimulate curiosity about local environments;…

  18. Explaining and Communicating Science Using Student-Created Blended Media

    ERIC Educational Resources Information Center

    Hoban, Garry; Nielsen, Wendy; Shepherd, Alyce

    2013-01-01

    Students engage with science content when they are asked to explain and communicate their knowledge to others. In particular, encouraging students to create various digital media forms such as videos, podcasts, vodcasts, screencasts, digital stories and animations to explain science is usually engaging, especially if they have ownership of the…

  19. Variation in Plant Traits Explains Global Biogeographic Variation in the Abundance of Major Forest Functional Types

    NASA Astrophysics Data System (ADS)

    Wang, Y.

    2015-12-01

    Contrasting leaf types (needle vs. broadleaf) with different lifespans (annual vs. perennial) represent different adaptive strategies of plants under different environmental conditions. Previous studies explained adaptive advantages of different strategies using empirical models but cannot adequately explain the co-dominance of multiple plant functional types (PFTs) as observed in many parts of the world. Here we used a process-based model to explore whether observed inter- and intra-PFT variation in key plant traits can explain global biogeographic variation in co-dominance of major forest functional types. Using a parameter screening method, we identified the four most important plant traits for simulating annual net primary production (NPP) using the Australian Community Atmosphere-Biosphere-Land Exchange model (CABLE). Using ensemble CABLE simulations, we estimated the fraction of global land cover attributed to each PFT by comparing the simulated NPP for all three PFTs at each land point, globally. Our results were consistent with land area cover fractions of major forest types estimated from remote sensing data products; i.e., evergreen needle-leaf forests dominate in boreal regions, evergreen broadleaf forests dominate in tropical regions, and deciduous broadleaf forests are distributed widely across a broad range of environmental conditions. More importantly our approach successfully explained a paradox that has puzzled ecologists for over a century: why evergreen leaf types dominate in both boreal and tropical regions. We conclude that variation in and co-variation between key plant traits can explain significant fractions of global biogeographic variation of three major forest types, and should be taken into account when simulating global vegetation dynamics.

  20. Literacy Strategies.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh. Instructional Services.

    The literacy strategies in this guide provide practical suggestions for teachers, regardless of discipline, to help middle school and high school students move to Levels III and IV on the North Carolina End-of-Grade Reading/Competency Tests. The strategies in the guide are designed for use with "inefficient" readers (not nonreaders). After an…

  1. Parsimonious snow model explains reindeer population dynamics and ranging behavior

    NASA Astrophysics Data System (ADS)

    Kohler, J.; Aanes, R.; Hansen, B. B.; Loe, L.; Severinsen, T.; Stien, A.

    2008-12-01

    Winter snow is a key factor affecting polar ecosystems. One example is the strong negative correlation of winter precipitation with fluctuations in population in some high-arctic animal populations. Ice layers within and at the base of the snowpack have particularly deleterious effects on such populations. Svalbard reindeer have small home ranges and are vulnerable to local "locked pasture" events due to ground-ice formation. When pastures are locked, reindeer are faced with the decision of staying, living off a diminishing fat store, or trying to escape beyond the unknown spatial borders of the ice. Both strategies may inhibit reproduction and increase mortality, leading to population declines. Here we assess the impact of winter snow and ice on the population dynamics of an isolated herd of Svalbard reindeer near Ny-Ålesund, monitored annually since 1978, with a retrospective analysis of the winter snowpack. Because there are no long-term observational records of snow or snow properties, such as ice layers, we must recourse to snowpack modeling. A parsimonious model of snow and ground-ice thickness is driven with daily temperature and precipitation data collected at a nearby weather station. The model uses the degree-day concept and has three adjustable parameters which are tuned to correlate model snow and ground-ice thicknesses to the limited observations available: April snow accumulation measurements on two local glaciers, and a limited number of ground-ice observations made in recent years. Parameter values used are comparable to those reported elsewhere. We find that modeled mean winter ground-ice thickness explains a significant percentage of the observed variance in reindeer population growth rate. Adding other explanatory parameters, such as modeled mean winter snowpack thickness or previous years' population size does not significanly improve the relation. Furthermore, positioning data from a small subset of reindeer show that model icing events are

  2. Enhancing School Success with Mnemonic Strategies.

    ERIC Educational Resources Information Center

    Mastropieri, Margo A.; Scruggs, Thomas E.

    1998-01-01

    Discusses instruction in mnemonics to help students with disabilities and learning difficulties improve memory for school content. Discusses what mnemonic strategies are; offers general techniques for improving memory; and explains (with examples) the mnemonic techniques of using keywords, using pegwords, and using letter strategies. Also provides…

  3. Strategy Strips for Self-Reliant Readers.

    ERIC Educational Resources Information Center

    Sowell, Dorothy J.

    2003-01-01

    Explains how reading strategy strips were developed to focus students' attention on specific reading steps. Notes that students became more personally knowledgeable and independent by using reading strategy strips. Proposes that their small-group participation helped them progress as collaborative thinkers. (PM)

  4. Methods and Strategies: Talk Strategies

    ERIC Educational Resources Information Center

    Shea, Lauren M.; Shanahan, Therese B.

    2011-01-01

    This article discusses how to promote oral language development through science. The authors describe how they incorporate academic "talk strategies" into science lessons in a nonintrusive and meaningful manner. These talk strategies are adapted from the "Avenues" (2007) curriculum for English learners (ELs), which gives examples of cooperative…

  5. Explainable expert systems: A research program in information processing

    NASA Technical Reports Server (NTRS)

    Paris, Cecile L.

    1993-01-01

    Our work in Explainable Expert Systems (EES) had two goals: to extend and enhance the range of explanations that expert systems can offer, and to ease their maintenance and evolution. As suggested in our proposal, these goals are complementary because they place similar demands on the underlying architecture of the expert system: they both require the knowledge contained in a system to be explicitly represented, in a high-level declarative language and in a modular fashion. With these two goals in mind, the Explainable Expert Systems (EES) framework was designed to remedy limitations to explainability and evolvability that stem from related fundamental flaws in the underlying architecture of current expert systems.

  6. Student and Teacher Perceptions of the Use of Multimedia Supported Predict-Observe-Explain Tasks To Probe Understanding.

    ERIC Educational Resources Information Center

    Kearney, Matthew; Treagust, David F.; Yeo, Shelley; Zadnik, Marjan G.

    2001-01-01

    Discusses student and teacher perceptions of a new development in the use of the predict-observe-explain (POE) strategy. This development involves the incorporation of POE tasks into a multimedia computer program that uses real-life, digital video clips of difficult, expensive, time consuming, or dangerous scenarios as stimuli for these tasks.…

  7. Personality and problem-solving performance explain competitive ability in the wild

    PubMed Central

    Cole, Ella F.; Quinn, John L.

    2012-01-01

    Competitive ability is a major determinant of fitness, but why individuals vary so much in their competitiveness remains only partially understood. One increasingly prevalent view is that realized competitive ability varies because it represents alternative strategies that arise because of the costs associated with competitiveness. Here we use a population of great tits (Parus major) to explore whether individual differences in competitive ability when foraging can be explained by two traits that have previously been linked to alternative behavioural strategies: the personality trait ‘exploration behaviour’ and a simple cognitive trait, ‘innovative problem-solving performance’. We assayed these traits under standardized conditions in captivity and then measured competitive ability at feeders with restricted access in the wild. Competitive ability was repeatable within individual males across days and correlated positively with exploration behaviour, representing the first such demonstration of a link between a personality trait and both competitive ability and food intake in the wild. Competitive ability was also simultaneously negatively correlated with problem-solving performance; individuals who were poor competitors were good at problem-solving. Rather than being the result of variation in ‘individual quality’, our results support the hypothesis that individual variation in competitive ability can be explained by alternative behavioural strategies. PMID:21937498

  8. Cetacean Strategies.

    ERIC Educational Resources Information Center

    Gilliland, Denise DelGrosso

    1991-01-01

    Suggested are activities about whales for children in schools not near the ocean. Activities designed to pique students' interest in whales and to investigate the size, breathing, buoyancy, and feeding strategies of whales are discussed. (CW)

  9. Strategy under uncertainty.

    PubMed

    Courtney, H; Kirkland, J; Viguerie, P

    1997-01-01

    At the heart of the traditional approach to strategy lies the assumption that by applying a set of powerful analytic tools, executives can predict the future of any business accurately enough to allow them to choose a clear strategic direction. But what happens when the environment is so uncertain that no amount of analysis will allow us to predict the future? What makes for a good strategy in highly uncertain business environments? The authors, consultants at McKinsey & Company, argue that uncertainty requires a new way of thinking about strategy. All too often, they say, executives take a binary view: either they underestimate uncertainty to come up with the forecasts required by their companies' planning or capital-budging processes, or they overestimate it, abandon all analysis, and go with their gut instinct. The authors outline a new approach that begins by making a crucial distinction among four discrete levels of uncertainty that any company might face. They then explain how a set of generic strategies--shaping the market, adapting to it, or reserving the right to play at a later time--can be used in each of the four levels. And they illustrate how these strategies can be implemented through a combination of three basic types of actions: big bets, options, and no-regrets moves. The framework can help managers determine which analytic tools can inform decision making under uncertainty--and which cannot. At a broader level, it offers executives a discipline for thinking rigorously and systematically about uncertainty and its implications for strategy. PMID:10174798

  10. Case-based reasoning to explain medical model exceptions.

    PubMed

    Schmidt, Rainer; Vorobieva, Olga

    2008-01-01

    In medicine many exceptions occur. In medical practise and in knowledge-based systems too, it is necessary to consider them and to deal with them appropriately. In medical studies and in research exceptions shall be explained. We present a system that helps to explain cases that do not fit into a theoretical hypothesis. Our starting points are situations where neither a well-developed theory nor reliable knowledge nor a proper case base is available. So, instead of reliable theoretical knowledge and intelligent experience, we have just some theoretical hypothesis and a set of measurements. In this paper, we propose to combine CBR with a statistical model. We use CBR to explain those cases that do not fit the model. The case base has to be set up incrementally, it contains the exceptional cases, and their explanations are the solutions, which can be used to help to explain further exceptional cases. PMID:18487741

  11. A Simple Threshold Rule Is Sufficient to Explain Sophisticated Collective Decision-Making

    PubMed Central

    Robinson, Elva J. H.; Franks, Nigel R.; Ellis, Samuel; Okuda, Saki; Marshall, James A. R.

    2011-01-01

    Decision-making animals can use slow-but-accurate strategies, such as making multiple comparisons, or opt for simpler, faster strategies to find a ‘good enough’ option. Social animals make collective decisions about many group behaviours including foraging and migration. The key to the collective choice lies with individual behaviour. We present a case study of a collective decision-making process (house-hunting ants, Temnothorax albipennis), in which a previously proposed decision strategy involved both quality-dependent hesitancy and direct comparisons of nests by scouts. An alternative possible decision strategy is that scouting ants use a very simple quality-dependent threshold rule to decide whether to recruit nest-mates to a new site or search for alternatives. We use analytical and simulation modelling to demonstrate that this simple rule is sufficient to explain empirical patterns from three studies of collective decision-making in ants, and can account parsimoniously for apparent comparison by individuals and apparent hesitancy (recruitment latency) effects, when available nests differ strongly in quality. This highlights the need to carefully design experiments to detect individual comparison. We present empirical data strongly suggesting that best-of-n comparison is not used by individual ants, although individual sequential comparisons are not ruled out. However, by using a simple threshold rule, decision-making groups are able to effectively compare options, without relying on any form of direct comparison of alternatives by individuals. This parsimonious mechanism could promote collective rationality in group decision-making. PMID:21629645

  12. Explaining the motherhood wage penalty during the early occupational career.

    PubMed

    Staff, Jeremy; Mortimer, Jeylan T

    2012-02-01

    Prior research shows that mothers earn lower hourly wages than women without children, and that this maternal wage penalty cannot be fully explained by differences between mothers and other women in work experience and job characteristics. This research examines whether the residual motherhood wage penalty results from differences between mothers and other women in the accumulation of work interruptions and breaks in schooling. Using longitudinal data for 486 women followed from ages 19 to 31 in the Minnesota Youth Development Study, we find that accumulated months not in the labor force and not enrolled in school explain the residual pay gap between mothers and other women. PMID:22037996

  13. Explaining patterns in the ratification of global environmental treaties

    NASA Technical Reports Server (NTRS)

    Cook, David W.

    1991-01-01

    A study was made of the ratification behavior of 160 countries with respect to 38 global environmental treaties. The study identifies and explains patterns in the ratification of treaties, providing two means of assessing the likelihood that any given country will support global environmental treaties. National ratification totals reveal a pattern of high ratification by countries in Western Europe, North America, Japan, Australia, and New Zealand. A country's standing within the range of high to low ratification rates can be explained by the statistical model developed in the study. This research allows one to identify countries likely to support global environmental treaties.

  14. Applying Metacognitive Strategies to Skimming Research Articles in an ESP Context

    ERIC Educational Resources Information Center

    Dhieb-Henia, Nebila

    2006-01-01

    The article focuses on explaining to post-secondary teachers how to teach their students to use metacognitive strategies to skim research articles in specialized fields. The author briefly explains metacognitive strategies in reading tasks and discusses the importance of strategy training and having a purpose in reading. The author then describes…

  15. [Potentiation strategies].

    PubMed

    Doumy, Olivier; Bennabi, Djamila; El-Hage, Wissam; Allaïli, Najib; Bation, Rémy; Bellivier, Frank; Holtzmann, Jérôme; Bubrovszky, Maxime; Camus, Vincent; Charpeaud, Thomas; Courvoisier, Pierre; d'Amato, Thierry; Garnier, Marion; Haesebaert, Frédéric; Bougerol, Thierry; Lançon, Christophe; Moliere, Fanny; Nieto, Isabel; Richieri, Raphaëlle; Saba, Ghassen; Courtet, Philippe; Vaiva, Guillaume; Leboyer, Marion; Llorca, Pierre-Michel; Aouizerate, Bruno; Haffen, Emmanuel

    2016-03-01

    Lithium is among the most classically recommended add-on therapeutic strategy for the management of depressive patients showing unsuccessful response to standard antidepressant medications. The effectiveness of the add-on strategy with lithium requires achieving plasma levels above 0.5 mEq/L. Mood-stabilizing antiepileptic drugs such as carbamazepine, valproate derivatives or lamotrigine have not demonstrated conclusive therapeutic effects for the management of depressive patients showing unsuccessful response to standard antidepressant medications. Thyroid hormones are considered among the currently recommended add-on therapeutic strategy for the management of depressive patients showing unsuccessful response to standard antidepressant medications. The effectiveness of the add-on strategy with thyroid hormones requires achieving plasma concentration of TSH close to the lower limits at the normal range (0.4 μUI/L) or even below it. Second-generation antipsychotics such as aripiprazole or quetiapine have consistently demonstrated significant therapeutic effects for the management of depressive patients showing unsuccessful response to standard antidepressant medications. Second-generation antipsychotics however require the careful monitoring of both cardiovascular and metabolic adverse effects. PMID:26970936

  16. Use of Cognitive Strategies by High School Social Studies Students

    ERIC Educational Resources Information Center

    Martin, Leisa A.

    2005-01-01

    This research study used grounded theory in an attempt to explain how 10th-grade public school students in average and advanced classes used strategies to learn material in their high school social studies classes. This study sought to understand the strategies that students used to learn information, the frequency of their strategy use, and the…

  17. "High 5!" Strategies to Enhance Comprehension of Expository Text

    ERIC Educational Resources Information Center

    Dymock, Susan; Nicholson, Tom

    2010-01-01

    This article reviews theoretical and research evidence to support the explicit and systematic teaching of five comprehension strategies that will help all students tackle expository texts with success. The article explains the "High 5!" strategies and how to teach them. An example of a lesson is included to show how the five strategies connect…

  18. Can motor imagery and hypnotic susceptibility explain Conversion Disorder with motor symptoms?

    PubMed

    Srzich, Alexander J; Byblow, Winston D; Stinear, James W; Cirillo, John; Anson, J Greg

    2016-08-01

    Marked distortions in sense of agency can be induced by hypnosis in susceptible individuals, including alterations in subjective awareness of movement initiation and control. These distortions, with associated disability, are similar to those experienced with Conversion Disorder (CD), an observation that has led to the hypothesis that hypnosis and CD share causal mechanisms. The purpose of this review is to explore the relationships among motor imagery (MI), hypnotic susceptibility, and CD, then to propose how MI ability may contribute to hypnotic responding and CD. Studies employing subjective assessments of mental imagery have found little association between imagery abilities and hypnotic susceptibility. A positive association between imagery abilities and hypnotic susceptibility becomes apparent when objective measures of imagery ability are employed. A candidate mechanism to explain motor responses during hypnosis is kinaesthetic MI, which engages a strategy that involves proprioception or the "feel" of movement when no movement occurs. Motor suppression imagery (MSI), a strategy involving inhibition of movement, may provide an alternate objective measurable phenomenon that underlies both hypnotic susceptibility and CD. Evidence to date supports the idea that there may be a positive association between kinaesthetic MI ability and hypnotic susceptibility. Additional evidence supports a positive association between hypnotic susceptibility and CD. Disturbances in kinaesthetic MI performance in CD patients indicate that MI mechanisms may also underlie CD symptoms. Further investigation of the above relationships is warranted to explain these phenomena, and establish theoretical explanations underlying sense of agency. PMID:27346334

  19. Territoriality and Conflict Avoidance Explain Asociality (Solitariness) of the Endosymbiotic Pea Crab Tunicotheres moseri.

    PubMed

    Ambrosio, Louis J; Baeza, J Antonio

    2016-01-01

    Host monopolization theory predicts symbiotic organisms inhabiting morphologically simple, relatively small and scarce hosts to live solitarily as a result of territorial behaviors. We tested this prediction with Tunicotheres moseri, an endosymbiotic crab dwelling in the atrial chamber of the morphologically simple, small, and relatively scarce ascidian Styela plicata. As predicted, natural populations of T. moseri inhabit ascidian hosts solitarily with greater frequency than expected by chance alone. Furthermore, laboratory experiments demonstrated that intruder crabs take significantly longer to colonize previously infected compared to uninfected hosts, indicating as expected, that resident crabs exhibit monopolization behaviors. While territoriality does occur, agonistic behaviors employed by T. moseri do not mirror the overt behaviors commonly reported for other territorial crustaceans. Documented double and triple cohabitations in the field coupled with laboratory observations demonstrating the almost invariable success of intruder crabs colonizing occupied hosts, suggest that territoriality is ineffective in completely explaining the solitary social habit of this species. Additional experiments showed that T. moseri juveniles and adults, when searching for ascidians use chemical cues to avoid hosts occupied by conspecifics. This conspecific avoidance behavior reported herein is a novel strategy most likely employed to preemptively resolve costly territorial conflicts. In general, this study supports predictions central to host monopolization theory, but also implies that alternative behavioral strategies (i.e., conflict avoidance) may be more important than originally thought in explaining the host use pattern of symbiotic organisms. PMID:26910474

  20. Territoriality and Conflict Avoidance Explain Asociality (Solitariness) of the Endosymbiotic Pea Crab Tunicotheres moseri

    PubMed Central

    Ambrosio, Louis J.; Baeza, J. Antonio

    2016-01-01

    Host monopolization theory predicts symbiotic organisms inhabiting morphologically simple, relatively small and scarce hosts to live solitarily as a result of territorial behaviors. We tested this prediction with Tunicotheres moseri, an endosymbiotic crab dwelling in the atrial chamber of the morphologically simple, small, and relatively scarce ascidian Styela plicata. As predicted, natural populations of T. moseri inhabit ascidian hosts solitarily with greater frequency than expected by chance alone. Furthermore, laboratory experiments demonstrated that intruder crabs take significantly longer to colonize previously infected compared to uninfected hosts, indicating as expected, that resident crabs exhibit monopolization behaviors. While territoriality does occur, agonistic behaviors employed by T. moseri do not mirror the overt behaviors commonly reported for other territorial crustaceans. Documented double and triple cohabitations in the field coupled with laboratory observations demonstrating the almost invariable success of intruder crabs colonizing occupied hosts, suggest that territoriality is ineffective in completely explaining the solitary social habit of this species. Additional experiments showed that T. moseri juveniles and adults, when searching for ascidians use chemical cues to avoid hosts occupied by conspecifics. This conspecific avoidance behavior reported herein is a novel strategy most likely employed to preemptively resolve costly territorial conflicts. In general, this study supports predictions central to host monopolization theory, but also implies that alternative behavioral strategies (i.e., conflict avoidance) may be more important than originally thought in explaining the host use pattern of symbiotic organisms. PMID:26910474

  1. Using Culture to Explain Behavior: An Integrative Cultural Approach

    ERIC Educational Resources Information Center

    Shepherd, Hana R.; Stephens, Nicole M.

    2010-01-01

    While savings rates among low-income families vary greatly, a 2008 National Poverty Center report finds that over 40 percent of low-income families fail to save any money. For decades policy makers and social scientists have sought to explain this phenomenon. Even after accounting for the fact that low-income families have less money to save, why…

  2. Explaining the Effects of Communities of Pastoral Care for Students

    ERIC Educational Resources Information Center

    Murphy, Joseph; Holste, Linda

    2016-01-01

    This article explains how communities of pastoral care work. It presents an empirically forged theory in action. We examined theoretical and empirical work across the targeted area of personalization for students. We also completed what Hallinger (2012) refers to as "exhaustive review" of the field of school improvement writ large. We…

  3. Children's Understanding of Substances, Part 2: Explaining Chemical Change.

    ERIC Educational Resources Information Center

    Johnson, Philip

    2002-01-01

    Focuses on the idea of chemical change and reports data from a study exploring the development of the concept of substance in children aged 11-14. Examines the use of the idea of elements, compounds, and bonding between atoms to explain chemical change and the intersection of these ideas with "basic" particle ideas. (Contains 21 references.)…

  4. Learning to Apply Models of Materials While Explaining Their Properties

    ERIC Educational Resources Information Center

    Karpin, Tiia; Juuti, Kalle; Lavonen, Jari

    2014-01-01

    Background: Applying structural models is important to chemistry education at the upper secondary level, but it is considered one of the most difficult topics to learn. Purpose: This study analyses to what extent in designed lessons students learned to apply structural models in explaining the properties and behaviours of various materials.…

  5. Explaining Learning: From Analysis to Paralysis to Hippocampus

    ERIC Educational Resources Information Center

    Clark, John

    2005-01-01

    This paper seeks to explain learning by examining five theories of learning--conceptual analysis, behavioural, constructivist, computational and connectionist. The first two are found wanting and rejected. Piaget's constructivist theory offers a general explanatory framework (assimilation and accommodation) but fails to provide an adequate account…

  6. A Quest to Explain the Extreme Realism in Newbery Books

    ERIC Educational Resources Information Center

    Miguez, Betsy Bryan; Goetting, Denise

    2006-01-01

    The quest to explain the extreme realism found in some Newbery Award books led the authors to discover that there is no unified view of childhood affecting children's literature today. While some adults feel that children must be protected against the evil surrounding them, others feel that they must be prepared to face the world in which they…

  7. Teacher Styles in Questioning and Explaining. Technical Report No. 39.

    ERIC Educational Resources Information Center

    Moore, Carol Ann

    The primary purpose of this study was to identify and describe individual differences in teaching style (i.e., teachers' patterns of questioning and explaining) in a standardized teaching situation. The secondary purpose was to explore relationships between teaching behavior and other teacher characteristics: teaching experience; sex and selected…

  8. Gender Differences in Explaining Grades Using Structural Equation Modeling

    ERIC Educational Resources Information Center

    Ruban, Lilia M.; McCoach, D. Betsy

    2005-01-01

    This study examined the differential impacts of SAT scores and high school rank, college academic level, motivational variables, and self-regulatory variables in explaining variance in the academic achievement of male and female collegians using structural equation modeling and multiple groups analyses. Significantly, in light of earlier research,…

  9. Visualisation and Reasoning in Explaining the Phases of the Moon

    ERIC Educational Resources Information Center

    Subramaniam, K.; Padalkar, Shamin

    2009-01-01

    In this study, we examine how subjects set up, transform, and reason with models that they establish on the basis of known facts as they seek to explain a familiar everyday phenomenon--the phases of the moon. An interview schedule was designed to elicit subjects' reasoning, and in the case where explanations were mistaken, to induce a change in…

  10. Explaining Common Variance Shared by Early Numeracy and Literacy

    ERIC Educational Resources Information Center

    Davidse, N. J.; De Jong, M. T.; Bus, A. G.

    2014-01-01

    How can it be explained that early literacy and numeracy share variance? We specifically tested whether the correlation between four early literacy skills (rhyming, letter knowledge, emergent writing, and orthographic knowledge) and simple sums (non-symbolic and story condition) reduced after taking into account preschool attention control,…

  11. Learning to apply models of materials while explaining their properties

    NASA Astrophysics Data System (ADS)

    Karpin, Tiia; Juuti, Kalle; Lavonen, Jari

    2014-09-01

    Background:Applying structural models is important to chemistry education at the upper secondary level, but it is considered one of the most difficult topics to learn. Purpose:This study analyses to what extent in designed lessons students learned to apply structural models in explaining the properties and behaviours of various materials. Sample:An experimental group is 27 Finnish upper secondary school students and control group included 18 students from the same school. Design and methods:In quasi-experimental setting, students were guided through predict, observe, explain activities in four practical work situations. It was intended that the structural models would encourage students to learn how to identify and apply appropriate models when predicting and explaining situations. The lessons, organised over a one-week period, began with a teacher's demonstration and continued with student experiments in which they described the properties and behaviours of six household products representing three different materials. Results:Most students in the experimental group learned to apply the models correctly, as demonstrated by post-test scores that were significantly higher than pre-test scores. The control group showed no significant difference between pre- and post-test scores. Conclusions:The findings indicate that the intervention where students engage in predict, observe, explain activities while several materials and models are confronted at the same time, had a positive effect on learning outcomes.

  12. Explaining Recent Army and Navy Minority Recruiting Trends. Research Brief

    ERIC Educational Resources Information Center

    Steinberg, Paul

    2009-01-01

    Between 2000 and 2007, the representation of blacks among high-quality Army recruits declined, while in the Navy, black representation remained stable; the representation of Hispanics among high-quality recruits in both the Army and Navy grew during this period. RAND researchers identified factors that explain these recruiting trends and found…

  13. Explaining the Socio-Economic Status School Completion Gap

    ERIC Educational Resources Information Center

    Polidano, Cain; Hanel, Barbara; Buddelmeyer, Hielke

    2013-01-01

    Relatively low rates of school completion among students from low socio-economic backgrounds is a key driver of intergenerational inequality. Linking data from the Programme for International Student Assessment with data from the Longitudinal Survey of Australian Youth, we use a decomposition framework to explain the gap in school completion rates…

  14. Analysis and Assessment of Students' Competency to Explain Geographical Processes

    ERIC Educational Resources Information Center

    Dulama, Maria-Eliza; Alexandru, Diana-Elena

    2010-01-01

    In this study we seek to analyse the ability of students to explain, exemplify and outline geographical processes, as well as to assess their competencies by using an evaluation grid. Therefore, we tested two types of hypotheses. The first one regards the fact that it becomes more difficult for students to represent a previously learned…

  15. The Role of Secondary Education in Explaining Competitiveness

    ERIC Educational Resources Information Center

    Baumann, Chris; Winzar, Hume

    2016-01-01

    The literature establishes that education drives economic performance, but the extent that education is associated with a country's competitiveness is empirically untested. Our study analyses Programme for International Student Assessment (PISA) data from 63 countries to ascertain education's role in explaining the competitiveness of a country.…

  16. Economic Models to Explain School Board Expenditures in Ontario.

    ERIC Educational Resources Information Center

    Lawton, Stephen B.

    1985-01-01

    Explains variations in per pupil expenditures among school boards in Ontario, Canada, using the "median voter model," which compares consumer behavior with government funding actions. With an inequitable tax price an important policy variable, the school grant program needs redesigning to achieve equity without sacrificing efficiency. Includes 21…

  17. Students Explaining Science—Assessment of Science Communication Competence

    NASA Astrophysics Data System (ADS)

    Kulgemeyer, Christoph; Schecker, Horst

    2013-12-01

    Science communication competence (SCC) is an important educational goal in the school science curricula of several countries. However, there is a lack of research about the structure and the assessment of SCC. This paper specifies the theoretical framework of SCC by a competence model. We developed a qualitative assessment method for SCC that is based on an expert-novice dialog: an older student (explainer, expert) explains a physics phenomenon to a younger peer (addressee, novice) in a controlled test setting. The explanations are video-recorded and analysed by qualitative content analysis. The method was applied in a study with 46 secondary school students as explainers. Our aims were (a) to evaluate whether our model covers the relevant features of SCC, (b) to validate the assessment method and (c) to find characteristics of addressee-adequate explanations. A performance index was calculated to quantify the explainers' levels of competence on an ordinal scale. We present qualitative and quantitative evidence that the index is adequate for assessment purposes. It correlates with results from a written SCC test and a perspective taking test (convergent validity). Addressee-adequate explanations can be characterized by use of graphical representations and deliberate switches between scientific and everyday language.

  18. Does a Corresponding Set of Variables for Explaining Voluntary Organizational Turnover Transfer to Explaining Voluntary Occupational Turnover?

    ERIC Educational Resources Information Center

    Blau, Gary

    2007-01-01

    This study proposed and tested corresponding sets of variables for explaining voluntary organizational versus occupational turnover for a sample of medical technologists. This study is believed to be the first test of the Rhodes and Doering (1983) occupational change model using occupational turnover data. Results showed that corresponding job…

  19. Mechanical vulnerability explains size-dependent mortality of reef corals

    PubMed Central

    Madin, Joshua S; Baird, Andrew H; Dornelas, Maria; Connolly, Sean R

    2014-01-01

    Understanding life history and demographic variation among species within communities is a central ecological goal. Mortality schedules are especially important in ecosystems where disturbance plays a major role in structuring communities, such as coral reefs. Here, we test whether a trait-based, mechanistic model of mechanical vulnerability in corals can explain mortality schedules. Specifically, we ask whether species that become increasingly vulnerable to hydrodynamic dislodgment as they grow have bathtub-shaped mortality curves, whereas species that remain mechanically stable have decreasing mortality rates with size, as predicted by classical life history theory for reef corals. We find that size-dependent mortality is highly consistent between species with the same growth form and that the shape of size-dependent mortality for each growth form can be explained by mechanical vulnerability. Our findings highlight the feasibility of predicting assemblage-scale mortality patterns on coral reefs with trait-based approaches. PMID:24894390

  20. Private nurses and playboy bunnies: explaining permissible sex discrimination.

    PubMed

    Yuracko, Kimberly A

    2004-01-01

    Discrimination on the basis of sex in employment is illegal--usually. In cases in which employers contend that sex-based hiring is necessary to protect the privacy interests of their customer, however, and in cases in which employers contend that sex-based hiring is necessary to provide a particular type of sexual titillation for their customers, courts sometimes do allow employers to discriminate. Courts say that they allow sex discrimination in employment when it is necessary to preserve the "essence of the business." This Article shows, however, that there is no plausible conception of business "essence" that can explain and make sense of the existing case law. The Article therefore looks beyond the courts' rhetoric to explain and defend why courts distinguish in the ways they do between permissible and impermissible sex discrimination in employment. PMID:15046068

  1. A developmental hypothesis to explain the multicentricity of breast cancer.

    PubMed

    Sharpe, C R

    1998-07-14

    In this article the author proposes that the multicentricity of breast cancer might be explained by a developmental hypothesis. Genetic alterations ("hits") occurring in epithelial stem cells during the development of the breast may be transmitted to populations of daughter cells during growth. As a result, areas of the breast may be predisposed to malignant transformation with the occurrence of further genetic hits. Areas with the same predisposition should be anatomically connected, and earlier hits during breast development should result in larger areas of predisposition. The multicentricity of breast cancer would be explained if multiple lesions--monoclonal for the predisposing genetic hit and polyclonal for subsequent hits--developed within a predisposed area. Multiple lesions arising from the spread of disease by extension would be expected to share many genetic hits. The author discusses the implications that further evidence supporting the developmental hypothesis would have for the prevention and treatment of breast cancer. PMID:9679488

  2. A developmental hypothesis to explain the multicentricity of breast cancer

    PubMed Central

    Sharpe, C R

    1998-01-01

    In this article the author proposes that the multicentricity of breast cancer might be explained by a developmental hypothesis. Genetic alterations ("hits") occurring in epithelial stem cells during the development of the breast may be transmitted to populations of daughter cells during growth. As a result, areas of the breast may be predisposed to malignant transformation with the occurrence of further genetic hits. Areas with the same predisposition should be anatomically connected, and earlier hits during breast development should result in larger areas of predisposition. The multicentricity of breast cancer would be explained if multiple lesions--monoclonal for the predisposing genetic hit and polyclonal for subsequent hits--developed within a predisposed area. Multiple lesions arising from the spread of disease by extension would be expected to share many genetic hits. The author discusses the implications that further evidence supporting the developmental hypothesis would have for the prevention and treatment of breast cancer. PMID:9679488

  3. Explaining dehumanization among children: the interspecies model of prejudice.

    PubMed

    Costello, Kimberly; Hodson, Gordon

    2014-03-01

    Although many theoretical approaches have emerged to explain prejudices expressed by children, none incorporate outgroup dehumanization, a key predictor of prejudice among adults. According to the Interspecies Model of Prejudice, beliefs in the human-animal divide facilitate outgroup prejudice through fostering animalistic dehumanization (Costello & Hodson, 2010). In the present investigation, White children attributed Black children fewer 'uniquely human' characteristics, representing the first systematic evidence of racial dehumanization among children (Studies 1 and 2). In Study 2, path analyses supported the Interspecies Model of Prejudice: children's human-animal divide beliefs predicted greater racial prejudice, an effect explained by heightened racial dehumanization. Similar patterns emerged among parents. Furthermore, parent Social Dominance Orientation predicted child prejudice indirectly through children's endorsement of a hierarchical human-animal divide and subsequent dehumanizing tendencies. Encouragingly, children's human-animal divide perceptions were malleable to an experimental prime highlighting animal-human similarity. Implications for prejudice interventions are considered. PMID:23083220

  4. Climate variation explains a third of global crop yield variability

    PubMed Central

    Ray, Deepak K.; Gerber, James S.; MacDonald, Graham K.; West, Paul C.

    2015-01-01

    Many studies have examined the role of mean climate change in agriculture, but an understanding of the influence of inter-annual climate variations on crop yields in different regions remains elusive. We use detailed crop statistics time series for ~13,500 political units to examine how recent climate variability led to variations in maize, rice, wheat and soybean crop yields worldwide. While some areas show no significant influence of climate variability, in substantial areas of the global breadbaskets, >60% of the yield variability can be explained by climate variability. Globally, climate variability accounts for roughly a third (~32–39%) of the observed yield variability. Our study uniquely illustrates spatial patterns in the relationship between climate variability and crop yield variability, highlighting where variations in temperature, precipitation or their interaction explain yield variability. We discuss key drivers for the observed variations to target further research and policy interventions geared towards buffering future crop production from climate variability. PMID:25609225

  5. Imitation explains the propagation, not the stability of animal culture

    PubMed Central

    Claidière, Nicolas; Sperber, Dan

    2010-01-01

    For acquired behaviour to count as cultural, two conditions must be met: it must propagate in a social group, and it must remain stable across generations in the process of propagation. It is commonly assumed that imitation is the mechanism that explains both the spread of animal culture and its stability. We review the literature on transmission chain studies in chimpanzees (Pan troglodytes) and other animals, and we use a formal model to argue that imitation, which may well play a major role in the propagation of animal culture, cannot be considered faithful enough to explain its stability. We consider the contribution that other psychological and ecological factors might make to the stability of animal culture observed in the wild. PMID:19889707

  6. Explaining large-scale patterns of vertebrate diversity

    PubMed Central

    Wiens, John J.

    2015-01-01

    The major clades of vertebrates differ dramatically in their current species richness, from 2 to more than 32 000 species each, but the causes of this variation remain poorly understood. For example, a previous study noted that vertebrate clades differ in their diversification rates, but did not explain why they differ. Using a time-calibrated phylogeny and phylogenetic comparative methods, I show that most variation in diversification rates among 12 major vertebrate clades has a simple ecological explanation: predominantly terrestrial clades (i.e. birds, mammals, and lizards and snakes) have higher net diversification rates than predominantly aquatic clades (i.e. amphibians, crocodilians, turtles and all fish clades). These differences in diversification rates are then strongly related to patterns of species richness. Habitat may be more important than other potential explanations for richness patterns in vertebrates (such as climate and metabolic rates) and may also help explain patterns of species richness in many other groups of organisms. PMID:26202428

  7. Computing measures of explained variation for logistic regression models.

    PubMed

    Mittlböck, M; Schemper, M

    1999-01-01

    The proportion of explained variation (R2) is frequently used in the general linear model but in logistic regression no standard definition of R2 exists. We present a SAS macro which calculates two R2-measures based on Pearson and on deviance residuals for logistic regression. Also, adjusted versions for both measures are given, which should prevent the inflation of R2 in small samples. PMID:10195643

  8. Earthquake lubrication and healing explained by amorphous nanosilica

    NASA Astrophysics Data System (ADS)

    Rowe, C. D.; Lamothe, K. G.; Rempe, M.; Andrews, M.; Mitchell, T. M.; Di Toro, G.; White, J. C.

    2015-12-01

    Earthquake slip and rupture propagation require fault strength to decrease during slip. Extreme shear weakening observed in laboratory friction experiments on silica-rich rocks has been explained by the formation of a hydrated amorphous 'silica gel' on the slip surface, but the mode of formation and deformation behavior of this material are not known. In addition, the wear material displays time-dependent strengthening on timescales of hours to days. We performed shearing experiments on chert rocks and analyzed the wear material formed at a range of slip rates from 10-4 - 10-1 m/s. We show by transmission electron microscopy (TEM) and X-ray diffraction that silica lubrication is the result of the formation of amorphous nanopowder rather than a gel. The nanopowder has distinct structure and properties when compared to commercially available amorphous silica nanoparticles, which result from the degree and distribution of hydration and the style of bond strain within particles (observed by Raman spectroscopy and FTIR). The lubrication effect is due to intra-particle plasticity, even at low temperature and interparticle lubrication caused by trapping of water layers between hydrated surfaces. The hours to days timescale of healing may be explained by the natural time-dependent sintering between the hydrated surfaces of the nanopowder. Formation of amorphous silica nanopowders during slip can explain the general characteristics of earthquake ruptures, including the timescales of coseismic weakening and post-seismic healing.

  9. Genetic Pleiotropy Explains Associations between Musical Auditory Discrimination and Intelligence

    PubMed Central

    Mosing, Miriam A.; Pedersen, Nancy L.; Madison, Guy; Ullén, Fredrik

    2014-01-01

    Musical aptitude is commonly measured using tasks that involve discrimination of different types of musical auditory stimuli. Performance on such different discrimination tasks correlates positively with each other and with intelligence. However, no study to date has explored these associations using a genetically informative sample to estimate underlying genetic and environmental influences. In the present study, a large sample of Swedish twins (N = 10,500) was used to investigate the genetic architecture of the associations between intelligence and performance on three musical auditory discrimination tasks (rhythm, melody and pitch). Phenotypic correlations between the tasks ranged between 0.23 and 0.42 (Pearson r values). Genetic modelling showed that the covariation between the variables could be explained by shared genetic influences. Neither shared, nor non-shared environment had a significant effect on the associations. Good fit was obtained with a two-factor model where one underlying shared genetic factor explained all the covariation between the musical discrimination tasks and IQ, and a second genetic factor explained variance exclusively shared among the discrimination tasks. The results suggest that positive correlations among musical aptitudes result from both genes with broad effects on cognition, and genes with potentially more specific influences on auditory functions. PMID:25419664

  10. Explaining the Early Development and Health of Teen Mothers’ Children*

    PubMed Central

    Mollborn, Stefanie; Dennis, Jeff A.

    2013-01-01

    The transmission of social disadvantage from teenage mothers to their children is well established, but when and why do these disparities emerge in the early life course? Using nationally representative data from the Early Childhood Longitudinal Study-Birth Cohort, this study investigated the relationship between teen childbearing and children’s cognition, behavior, and health from infancy through preschool. Developmental disparities between teenage mothers’ children and others were largely nonexistent at 9 months but accumulated with age. Having a teenage mother predicted compromised development across several domains by age 4½. Our conceptual model expected preexisting disadvantage, ongoing resource disadvantage, and compromised parenting quality to explain the association between teen childbearing and child outcomes. Preexisting social disadvantage accounted for much of this relationship. Financial, social, and material resources in the child’s household partially or fully explained each of the remaining significant relationships between teenage childbearing and child outcomes. Parenting quality explained a smaller proportion of these relationships than did resources, and these factors’ influences were largely independent. Because children of teenage mothers with a modest set of resources were not predicted to have compromised development, resources provided in early childhood may have the potential to reduce developmental disparities for teenage mothers’ children. PMID:23630407

  11. Explaining Racial Disparities in Infant Health in Brazil

    PubMed Central

    Nyarko, Kwame A.; Lopez-Camelo, Jorge; Castilla, Eduardo E.

    2013-01-01

    Objectives. We sought to quantify how socioeconomic, health care, demographic, and geographic effects explain racial disparities in low birth weight (LBW) and preterm birth (PTB) rates in Brazil. Methods. We employed a sample of 8949 infants born between 1995 and 2009 in 15 cities and 7 provinces in Brazil. We focused on disparities in LBW (< 2500 g) and PTB (< 37 gestational weeks) prevalence between infants of African ancestry alone or African mixed with other ancestries, and European ancestry alone. We used a decomposition model to quantify the contributions of conceptually relevant factors to these disparities. Results. The model explained 45% to 94% of LBW and 64% to 94% of PTB disparities between the African ancestry groups and European ancestry. Differences in prenatal care use and geographic location were the most important contributors, followed by socioeconomic differences. The model explained the majority of the disparities for mixed African ancestry and part of the disparity for African ancestry alone. Conclusions. Public policies to improve children’s health should target prenatal care and geographic location differences to reduce health disparities between infants of African and European ancestries in Brazil. PMID:23409894

  12. Weather explains high annual variation in butterfly dispersal.

    PubMed

    Kuussaari, Mikko; Rytteri, Susu; Heikkinen, Risto K; Heliölä, Janne; von Bagh, Peter

    2016-07-27

    Weather conditions fundamentally affect the activity of short-lived insects. Annual variation in weather is therefore likely to be an important determinant of their between-year variation in dispersal, but conclusive empirical studies are lacking. We studied whether the annual variation of dispersal can be explained by the flight season's weather conditions in a Clouded Apollo (Parnassius mnemosyne) metapopulation. This metapopulation was monitored using the mark-release-recapture method for 12 years. Dispersal was quantified for each monitoring year using three complementary measures: emigration rate (fraction of individuals moving between habitat patches), average residence time in the natal patch, and average distance moved. There was much variation both in dispersal and average weather conditions among the years. Weather variables significantly affected the three measures of dispersal and together with adjusting variables explained 79-91% of the variation observed in dispersal. Different weather variables became selected in the models explaining variation in three dispersal measures apparently because of the notable intercorrelations. In general, dispersal rate increased with increasing temperature, solar radiation, proportion of especially warm days, and butterfly density, and decreased with increasing cloudiness, rainfall, and wind speed. These results help to understand and model annually varying dispersal dynamics of species affected by global warming. PMID:27440662

  13. Explaining formation of Astronomical Jets using Dynamic Universe Model

    NASA Astrophysics Data System (ADS)

    Naga Parameswara Gupta, Satyavarapu

    2016-07-01

    Astronomical jets are observed from the centres of many Galaxies including our own Milkyway. The formation of such jet is explained using SITA simulations of Dynamic Universe Model. For this purpose the path traced by a test neutron is calculated and depicted using a set up of one densemass of the mass equivalent to mass of Galaxy center, 90 stars with similar masses of stars near Galaxy center, mass equivalents of 23 Globular Cluster groups, 16 Milkyway parts, Andromeda and Triangulum Galaxies at appropriate distances. Five different kinds of theoretical simulations gave positive results The path travelled by this test neutron was found to be an astronomical jet emerging from Galaxy center. This is another result from Dynamic Universe Model. It solves new problems like a. Variable Mass Rocket Trajectory Problem b. Explaining Very long baseline interferometry (VLBI) observations c. Astronomical jets observed from Milkyway Center d. Prediction of Blue shifted Galaxies e. Explaining Pioneer Anomaly f. Prediction of New Horizons satellite trajectory etc. Dynamic Universe Model never reduces to General relativity on any condition. It uses a different type of mathematics based on Newtonian physics. This mathematics used here is simple and straightforward. As there are no differential equations present in Dynamic Universe Model, the set of equations give single solution in x y z Cartesian coordinates for every point mass for every time step

  14. Predator mimicry, not conspicuousness, explains the efficacy of butterfly eyespots

    PubMed Central

    De Bona, Sebastiano; Valkonen, Janne K.; López-Sepulcre, Andrés; Mappes, Johanna

    2015-01-01

    Large conspicuous eyespots on butterfly wings have been shown to deter predators. This has been traditionally explained by mimicry of vertebrate eyes, but recently the classic eye-mimicry hypothesis has been challenged. It is proposed that the conspicuousness of the eyespot, not mimicry, is what causes aversion due to sensory biases, neophobia or sensory overloads. We conducted an experiment to directly test whether the eye-mimicry or the conspicuousness hypothesis better explain eyespot efficacy. We used great tits (Parus major) as model predator, and tested their reaction towards animated images on a computer display. Birds were tested against images of butterflies without eyespots, with natural-looking eyespots, and manipulated spots with the same contrast but reduced resemblance to an eye, as well as images of predators (owls) with and without eyes. We found that mimetic eyespots were as effective as true eyes of owls and more efficient in eliciting an aversive response than modified, less mimetic but equally contrasting eyespots. We conclude that the eye-mimicry hypothesis explains our results better than the conspicuousness hypothesis and is thus likely to be an important mechanism behind the evolution of butterfly eyespots. PMID:25854889

  15. Predator mimicry, not conspicuousness, explains the efficacy of butterfly eyespots.

    PubMed

    De Bona, Sebastiano; Valkonen, Janne K; López-Sepulcre, Andrés; Mappes, Johanna

    2015-05-01

    Large conspicuous eyespots on butterfly wings have been shown to deter predators. This has been traditionally explained by mimicry of vertebrate eyes, but recently the classic eye-mimicry hypothesis has been challenged. It is proposed that the conspicuousness of the eyespot, not mimicry, is what causes aversion due to sensory biases, neophobia or sensory overloads. We conducted an experiment to directly test whether the eye-mimicry or the conspicuousness hypothesis better explain eyespot efficacy. We used great tits (Parus major) as model predator, and tested their reaction towards animated images on a computer display. Birds were tested against images of butterflies without eyespots, with natural-looking eyespots, and manipulated spots with the same contrast but reduced resemblance to an eye, as well as images of predators (owls) with and without eyes. We found that mimetic eyespots were as effective as true eyes of owls and more efficient in eliciting an aversive response than modified, less mimetic but equally contrasting eyespots. We conclude that the eye-mimicry hypothesis explains our results better than the conspicuousness hypothesis and is thus likely to be an important mechanism behind the evolution of butterfly eyespots. PMID:25854889

  16. Explaining ecological clusters of maternal depression in South Western Sydney

    PubMed Central

    2014-01-01

    Background The aim of the qualitative study reported here was to: 1) explain the observed clustering of postnatal depressive symptoms in South Western Sydney; and 2) identify group-level mechanisms that would add to our understanding of the social determinants of maternal depression. Methods Critical realism provided the methodological underpinning for the study. The setting was four local government areas in South Western Sydney, Australia. Child and Family practitioners and mothers in naturally occurring mothers groups were interviewed. Results Using an open coding approach to maximise emergence of patterns and relationships we have identified seven theoretical concepts that might explain the observed spatial clustering of maternal depression. The theoretical concepts identified were: Community-level social networks; Social Capital and Social Cohesion; "Depressed community"; Access to services at the group level; Ethnic segregation and diversity; Supportive social policy; and Big business. Conclusions We postulate that these regional structural, economic, social and cultural mechanisms partially explain the pattern of maternal depression observed in families and communities within South Western Sydney. We further observe that powerful global economic and political forces are having an impact on the local situation. The challenge for policy and practice is to support mothers and their families within this adverse regional and global-economic context. PMID:24460690

  17. Explaining Racial Disparities in Infant Health in Brazil

    PubMed Central

    Nyarko, Kwame A.; Lopez-Camelo, Jorge; Castilla, Eduardo E.

    2015-01-01

    Objectives. We sought to quantify how socioeconomic, health care, demographic, and geographic effects explain racial disparities in low birth weight (LBW) and preterm birth (PTB) rates in Brazil. Methods. We employed a sample of 8949 infants born between 1995 and 2009 in 15 cities and 7 provinces in Brazil. We focused on disparities in LBW (< 2500 g) and PTB (< 37 gestational weeks) prevalence between infants of African ancestry alone or African mixed with other ancestries, and European ancestry alone. We used a decomposition model to quantify the contributions of conceptually relevant factors to these disparities. Results. The model explained 45% to 94% of LBW and 64% to 94% of PTB disparities between the African ancestry groups and European ancestry. Differences in prenatal care use and geographic location were the most important contributors, followed by socioeconomic differences. The model explained the majority of the disparities for mixed African ancestry and part of the disparity for African ancestry alone. Conclusions. Public policies to improve children’s health should target prenatal care and geographic location differences to reduce health disparities between infants of African and European ancestries in Brazil. PMID:26313046

  18. The TTF Model To Explain PCK in Teacher Development.

    ERIC Educational Resources Information Center

    Veal, William R.

    This paper describes the development of pedagogical content knowledge (PCK) in secondary chemistry and physics preservice teachers. Teacher beliefs are intricately tied to how they make decisions for implementing instructional strategies, and those beliefs aid in the development of pedagogical content knowledge. A model for pedagogical content…

  19. What's your lab's strategy?

    PubMed

    Francis, Peter

    2016-07-01

    Important strategic choices cascade throughout a laboratory. Senior management should create a document that answers each of the five key questions explained on page 60. Once this has been detailed in writing, it remains important to disseminate the basics to all employees so they are singing the same tune. A useful way to accomplish this is through a coherent strategy statement that specifies three components: 1) objectives; 2) scope; and 3) advantages. Commercial and hospital outreach labs should be in business to win. It all starts with a definition of what winning looks like. To "participate" in your market contributes to mediocrity-and it's self-defeating. With no clear strategic direction of where-to-play and how-to-win choices that associate with the aspiration, a mission or vision statement can be frustrating rather than inspiring for employees. Articulate it plainly and concisely for everybody. With a care-fully prepared and designed strategy, you will be on your way to winning in the zero-sum game! PMID:27548928

  20. Traits underpinning desiccation resistance explain distribution patterns of terrestrial isopods.

    PubMed

    Dias, André T C; Krab, Eveline J; Mariën, Janine; Zimmer, Martin; Cornelissen, Johannes H C; Ellers, Jacintha; Wardle, David A; Berg, Matty P

    2013-07-01

    Predicted changes in soil water availability regimes with climate and land-use change will impact the community of functionally important soil organisms, such as macro-detritivores. Identifying and quantifying the functional traits that underlie interspecific differences in desiccation resistance will enhance our ability to predict both macro-detritivore community responses to changing water regimes and the consequences of the associated species shifts for organic matter turnover. Using path analysis, we tested (1) how interspecific differences in desiccation resistance among 22 northwestern European terrestrial isopod species could be explained by three underlying traits measured under standard laboratory conditions, namely, body ventral surface area, water loss rate and fatal water loss; (2) whether these relationships were robust to contrasting experimental conditions and to the phylogenetic relatedness effects being excluded; (3) whether desiccation resistance and hypothesized underlying traits could explain species distribution patterns in relation to site water availability. Water loss rate and (secondarily) fatal water loss together explained 90% of the interspecific variation in desiccation resistance. Our path model indicated that body surface area affects desiccation resistance only indirectly via changes in water loss rate. Our results also show that soil moisture determines isopod species distributions by filtering them according to traits underpinning desiccation resistance. These findings reveal that it is possible to use functional traits measured under standard conditions to predict soil biota responses to water availability in the field over broad spatial scales. Taken together, our results demonstrate an increasing need to generate mechanistic models to predict the effect of global changes on functionally important organisms. PMID:23224790

  1. Psychological Factors Explaining the Referral Behavior of Iranian Family Physicians

    PubMed Central

    Mohaghegh, Bahram; Seyedin, Hesam; Rashidian, Arash; Ravaghi, Hamid; Khalesi, Nader; Kazemeini, Hossein

    2014-01-01

    Background: The recently developed policy of the family practice program in rural regions of Iran faced some challenges such as inefficient referral system. The health insurance organizations (purchaser) and health policy makers are concerned about the high rate of patient referrals from family physicians to specialists due to imposing unnecessary services and costs. Objectives: This study examined utility of the theory of planned behavior to explain intention of Iranian family physicians to reduce referral rate of patients with respiratory diseases to medical specialist. Patients and Methods: An exploratory cross-sectional study, employing a correlational design directed by the theory of planned behavior was conducted. A questionnaire was developed based on an eliciting study and review of literature. One hundred and seventy-four family physicians working at primary care centers in two provinces of Iran completed the questionnaire (response rate of 86%). Results: The finding revealed that intention of family physicians to reduce referral rate of patients to specialists was significantly related to two theory-based variables of subjective norms (r = 0.38, P < 0.001) and perceived behavioral control (r = 0.43, P < 0.001), and not to attitudes. A stepwise regression entering direct measures of the theory variables explained 35% of the variance on the intention, with perceived behavioral control being the strongest predictor. Adding background variables to the model achieved further 5% by variables of practice size and past referral rate behavior. Conclusions: The results indicated that psychological variables of the theory of planned behavior could explain a noticeable proportion of variance in family physician's intention to decrease the rate of referring patients with respiratory diseases to medical specialists. The intention is primarily influenced by normative and control considerations. These findings contribute to a better understanding of referral decisions by

  2. Does cultural integration explain a mental health advantage for adolescents?

    PubMed Central

    Bhui, Kamaldeep S; Lenguerrand, Erik; Maynard, Maria J; Stansfeld, Stephen A; Harding, Seeromanie

    2012-01-01

    Background A mental health advantage has been observed among adolescents in urban areas. This prospective study tests whether cultural integration measured by cross-cultural friendships explains a mental health advantage for adolescents. Methods A prospective cohort of adolescents was recruited from 51 secondary schools in 10 London boroughs. Cultural identity was assessed by friendship choices within and across ethnic groups. Cultural integration is one of four categories of cultural identity. Using gender-specific linear-mixed models we tested whether cultural integration explained a mental health advantage, and whether gender and age were influential. Demographic and other relevant factors, such as ethnic group, socio-economic status, family structure, parenting styles and perceived racism were also measured and entered into the models. Mental health was measured by the Strengths and Difficulties Questionnaire as a ‘total difficulties score’ and by classification as a ‘probable clinical case’. Results A total of 6643 pupils in first and second years of secondary school (ages 11–13 years) took part in the baseline survey (2003/04) and 4785 took part in the follow-up survey in 2005–06. Overall mental health improved with age, more so in male rather than female students. Cultural integration (friendships with own and other ethnic groups) was associated with the lowest levels of mental health problems especially among male students. This effect was sustained irrespective of age, ethnicity and other potential explanatory variables. There was a mental health advantage among specific ethnic groups: Black Caribbean and Black African male students (Nigerian/Ghanaian origin) and female Indian students. This was not fully explained by cultural integration, although cultural integration was independently associated with better mental health. Conclusions Cultural integration was associated with better mental health, independent of the mental health advantage

  3. Explaining cross-country variation in cigarette consumption

    PubMed Central

    Srinivas, Kolluru; Rao, Bhanoji

    2009-01-01

    This short paper uses cross-country data on per capita cigarette consumption and selected socio-economic variables to explain inter-country differentials in consumption. It is found that the proportion of the aged in the total population and higher literacy among women have relatively greater and positive impact on cigarette consumption. Even after controlling for the effect of the two variables, a country's industrialized status has a positive impact on consumption. It would thus seem that aging and economic, and social developments are pro-cigarette consumption. PMID:19133163

  4. A third alternative to explain recent observations: Future deceleration

    NASA Astrophysics Data System (ADS)

    Chakraborty, Subenoy; Pan, Supriya; Saha, Subhajit

    2014-11-01

    In the present work we discuss a third alternative to explain the latest observational data concerning the accelerating Universe and its different stages. The particle creation mechanism in the framework of non-equilibrium thermodynamics is considered as a basic cosmic mechanism acting on the flat FRW geometry. By assuming that the gravitationally induced particle production occurs under "adiabatic" conditions, the deceleration parameter is expressed in terms of the particle creation rate which is chosen as a truncated power series of the Hubble parameter. The model shows the evolution of the Universe starting from inflation to the present late time acceleration and it also predicts future decelerating stage.

  5. Explaining and overcoming barriers to climate change adaptation

    NASA Astrophysics Data System (ADS)

    Eisenack, Klaus; Moser, Susanne C.; Hoffmann, Esther; Klein, Richard J. T.; Oberlack, Christoph; Pechan, Anna; Rotter, Maja; Termeer, Catrien J. A. M.

    2014-10-01

    The concept of barriers is increasingly used to describe the obstacles that hinder the planning and implementation of climate change adaptation. The growing literature on barriers to adaptation reveals not only commonly reported barriers, but also conflicting evidence, and few explanations of why barriers exist and change. There is thus a need for research that focuses on the interdependencies between barriers and considers the dynamic ways in which barriers develop and persist. Such research, which would be actor-centred and comparative, would help to explain barriers to adaptation and provide insights into how to overcome them.

  6. Crystal Structure Anisotropy Explains Anomalous Elastic Properties of Metal Nanorods

    NASA Astrophysics Data System (ADS)

    Goupalov, Serguei

    2014-03-01

    It is demonstrated that the frequency of the extensional vibrational mode of a nanorod made of an elastically anisotropic crystalline material deviates widely from the predictions of the theories based on the analysis of the long-wavelength limit. The dispersion relation for the fundamental extensional mode of a gold rod grown in the [ 100 ] direction is calculated and found to be in an excellent agreement with experimental data obtained from the transient optical absorption measurements on gold nanorods.[1] This explains an anomaly in the elastic properties of nanorods which was previously attributed to a 26% decrease in Young's modulus for nanorods compared to its bulk value.

  7. Decaying dark matter can explain the e{sup {+-}} excesses

    SciTech Connect

    Nardi, Enrico; Sannino, Francesco; Strumia, Alessandro E-mail: astrumia@mail.df.unipi.it

    2009-01-15

    PAMELA and ATIC recently reported excesses in e{sup {+-}} cosmic rays. Since the interpretation in terms of DM annihilations was found to be not easily compatible with constraints from photon observations, we consider the DM decay hypothesis and find that it can explain the e{sup {+-}} excesses compatibly with all constraints, and can be tested by dedicated HESS observations of the Galactic Ridge. ATIC data indicate a DM mass of about 2 TeV: this mass naturally implies the observed DM abundance relative to ordinary matter if DM is a quasi-stable composite particle with a baryon-like matter asymmetry. Technicolor naturally yields these type of candidates.

  8. Explaining human uniqueness: genome interactions with environment, behaviour and culture

    PubMed Central

    Varki, Ajit; Geschwind, Daniel H.; Eichler, Evan E.

    2009-01-01

    What makes us human? Specialists in each discipline respond through the lens of their own expertise. In fact, ‘anthropogeny’ (explaining the origin of humans) requires a transdisciplinary approach that eschews such barriers. Here we take a genomic and genetic perspective towards molecular variation, explore systems analysis of gene expression and discuss an organ-systems approach. Rejecting any ‘genes versus environment’ dichotomy, we then consider genome interactions with environment, behaviour and culture, finally speculating that aspects of human uniqueness arose because of a primate evolutionary trend towards increasing and irreversible dependence on learned behaviours and culture — perhaps relaxing allowable thresholds for large-scale genomic diversity. PMID:18802414

  9. Risk communication strategy development using the aerospace systems engineering process

    NASA Technical Reports Server (NTRS)

    Dawson, S.; Sklar, M.

    2004-01-01

    This paper explains the goals and challenges of NASA's risk communication efforts and how the Aerospace Systems Engineering Process (ASEP) was used to map the risk communication strategy used at the Jet Propulsion Laboratory to achieve these goals.

  10. Strategies of Educational Decentralization: Key Questions and Core Issues.

    ERIC Educational Resources Information Center

    Hanson, E. Mark

    1998-01-01

    Explains key issues and forces that shape organization and management strategies of educational decentralization, using examples from Colombia, Venezuela, Argentina, Nicaragua, and Spain. Core decentralization issues include national and regional goals, planning, political stress, resource distribution, infrastructure development, and job…

  11. Strategy and the Internet.

    PubMed

    Porter, M E

    2001-03-01

    Many of the pioneers of Internet business, both dot-coms and established companies, have competed in ways that violate nearly every precept of good strategy. Rather than focus on profits, they have chased customers indiscriminately through discounting, channel incentives, and advertising. Rather than concentrate on delivering value that earns an attractive price from customers, they have pursued indirect revenues such as advertising and click-through fees. Rather than make trade-offs, they have rushed to offer every conceivable product or service. It did not have to be this way--and it does not have to be in the future. When it comes to reinforcing a distinctive strategy, Michael Porter argues, the Internet provides a better technological platform than previous generations of IT. Gaining competitive advantage does not require a radically new approach to business; it requires building on the proven principles of effective strategy. Porter argues that, contrary to recent thought, the Internet is not disruptive to most existing industries and established companies. It rarely nullifies important sources of competitive advantage in an industry; it often makes them even more valuable. And as all companies embrace Internet technology, the Internet itself will be neutralized as a source of advantage. Robust competitive advantages will arise instead from traditional strengths such as unique products, proprietary content, and distinctive physical activities. Internet technology may be able to fortify those advantages, but it is unlikely to supplant them. Porter debunks such Internet myths as first-mover advantage, the power of virtual companies, and the multiplying rewards of network effects. He disentangles the distorted signals from the marketplace, explains why the Internet complements rather than cannibalizes existing ways of doing business, and outlines strategic imperatives for dot-coms and traditional companies. PMID:11246925

  12. Two cellular hypotheses explaining the initiation of ketamine's antidepressant actions: Direct inhibition and disinhibition.

    PubMed

    Miller, Oliver H; Moran, Jacqueline T; Hall, Benjamin J

    2016-01-01

    A single, low dose of ketamine evokes antidepressant actions in depressed patients and in patients with treatment-resistant depression (TRD). Unlike classic antidepressants, which regulate monoamine neurotransmitter systems, ketamine is an antagonist of the N-methyl-D-aspartate (NMDA) family of glutamate receptors. The effectiveness of NMDAR antagonists in TRD unveils a new set of targets for therapeutic intervention in major depressive disorder (MDD) and TRD. However, a better understanding of the cellular mechanisms underlying these effects is required for guiding future therapeutic strategies, in order to minimize side effects and prolong duration of efficacy. Here we review the evidence for and against two hypotheses that have been proposed to explain how NMDAR antagonism initiates protein synthesis and increases excitatory synaptic drive in corticolimbic brain regions, either through selective antagonism of inhibitory interneurons and cortical disinhibition, or by direct inhibition of cortical pyramidal neurons. This article is part of the Special Issue entitled 'Synaptopathy--from Biology to Therapy'. PMID:26211972

  13. Explaining seasonal fluctuations of measles in Niger using nighttime lights imagery.

    PubMed

    Bharti, N; Tatem, A J; Ferrari, M J; Grais, R F; Djibo, A; Grenfell, B T

    2011-12-01

    Measles epidemics in West Africa cause a significant proportion of vaccine-preventable childhood mortality. Epidemics are strongly seasonal, but the drivers of these fluctuations are poorly understood, which limits the predictability of outbreaks and the dynamic response to immunization. We show that measles seasonality can be explained by spatiotemporal changes in population density, which we measure by quantifying anthropogenic light from satellite imagery. We find that measles transmission and population density are highly correlated for three cities in Niger. With dynamic epidemic models, we demonstrate that measures of population density are essential for predicting epidemic progression at the city level and improving intervention strategies. In addition to epidemiological applications, the ability to measure fine-scale changes in population density has implications for public health, crisis management, and economic development. PMID:22158822

  14. Plate-wide stress relaxation explains European Palaeocene basin inversions.

    PubMed

    Nielsen, Søren B; Thomsen, Erik; Hansen, David L; Clausen, Ole R

    2005-05-12

    During Late Cretaceous and Cenozoic times, many Palaeozoic and Mesozoic rifts and basin structures in the interior of the European continent underwent several phases of inversion (the process of shortening a previously extensional basin). The main phases occurred during the Late Cretaceous and Middle Palaeocene, and have been previously explained by pulses of compression, mainly from the Alpine orogen. Here we show that the main phases differed both in structural style and cause. The Cretaceous phase was characterized by narrow uplift zones, reverse activation of faults, crustal shortening, and the formation of asymmetric marginal troughs. In contrast, the Middle Palaeocene phase was characterized by dome-like uplift of a wider area with only mild fault movements, and formation of more distal and shallow marginal troughs. A simple flexural model explains how domal, secondary inversion follows inevitably from primary, convergence-related inversion on relaxation of the in-plane tectonic stress. The onset of relaxation inversions was plate-wide and simultaneous, and may have been triggered by stress changes caused by elevation of the North Atlantic lithosphere by the Iceland plume or the drop in the north-south convergence rate between Africa and Europe. PMID:15889089

  15. Explaining the footsteps, belly dancer, Wenceslas, and kickback illusions.

    PubMed

    Howe, Piers D L; Thompson, Peter G; Anstis, Stuart M; Sagreiya, Hersh; Livingstone, Margaret S

    2006-01-01

    The footsteps illusion (FI) demonstrates that an object's background can have a profound effect on the object's perceived speed. This illusion consists of a yellow bar and a blue bar that move over a black-and-white, striped background. Although the bars move at a constant rate, they appear to repeatedly accelerate and decelerate in antiphase with each other. Previously, this illusion has been explained in terms of the variations in contrast at the leading and trailing edges of the bars that occur as the bars traverse the striped background. Here, we show that this explanation is inadequate and instead propose that for each bar, the bar's leading edge, trailing edge, lateral edges, and the surrounding background edges all contribute to the bar's perceived speed and that the degree to which each edge contributes to the motion percept is determined by that edge's contrast. We show that this theory can explain all the data on the FI as well as the belly dancer and Wenceslas illusions. We conclude by presenting a new illusion, the kickback illusion, which, although geometrically similar to the FI, is mediated by a different mechanism, namely, reverse phi motion. PMID:17209742

  16. Explaining fruit and vegetable intake using a consumer marketing tool.

    PubMed

    Della, Lindsay J; Dejoy, David M; Lance, Charles E

    2009-10-01

    In response to calls to reinvent the 5 A Day fruit and vegetable campaign, this study assesses the utility of VALS, a consumer-based audience segmentation tool that divides the U.S. population into groups leading similar lifestyles. The study examines whether the impact of theory of planned behavior (TPB) constructs varies across VALS groups in a cross-sectional sample of 1,588 U.S. adults. In a multigroup structural equation model, the VALS audience group variable moderated latent TPB relationships. Attitudes, subjective norms, and perceived behavioral control explained 57% to 70% of the variation in intention to eat fruit and vegetables across 5 different VALS groups. Perceived behavioral control and intention also predicted self-reported consumption behavior (R2 = 20% to 71% across VALS groups). Bivariate z tests were calculated to determine statistical differences in parameter estimates across groups. Nine of the bivariate z tests were statistically significant (p < or = .04), with standardized coefficients ranging from .05 to .70. These findings confirm the efficacy of using the TPB to explain variation in fruit and vegetable consumption as well as the validity of using a consumer-based algorithm to segment audiences for fruit and vegetable consumption messaging. PMID:19158253

  17. Can Chunk Size Differences Explain Developmental Changes in Lexical Learning?

    PubMed

    Smalle, Eleonore H M; Bogaerts, Louisa; Simonis, Morgane; Duyck, Wouter; Page, Michael P A; Edwards, Martin G; Szmalec, Arnaud

    2015-01-01

    In three experiments, we investigated Hebb repetition learning (HRL) differences between children and adults, as a function of the type of item (lexical vs. sub-lexical) and the level of item-overlap between sequences. In a first experiment, it was shown that when non-repeating and repeating (Hebb) sequences of words were all permutations of the same words, HRL was slower than when the sequences shared no words. This item-overlap effect was observed in both children and adults. In a second experiment, we used syllable sequences and we observed reduced HRL due to item-overlap only in children. The findings are explained within a chunking account of the HRL effect on the basis of which we hypothesize that children, compared with adults, chunk syllable sequences in smaller units. By hypothesis, small chunks are more prone to interference from anagram representations included in the filler sequences, potentially explaining the item-overlap effect in children. This hypothesis was tested in a third experiment with adults where we experimentally manipulated the chunk size by embedding pauses in the syllable sequences. Interestingly, we showed that imposing a small chunk size caused adults to show the same behavioral effects as those observed in children. Departing from the analogy between verbal HRL and lexical development, the results are discussed in light of the less-is-more hypothesis of age-related differences in language acquisition. PMID:26779065

  18. Can Chunk Size Differences Explain Developmental Changes in Lexical Learning?

    PubMed Central

    Smalle, Eleonore H. M.; Bogaerts, Louisa; Simonis, Morgane; Duyck, Wouter; Page, Michael P. A.; Edwards, Martin G.; Szmalec, Arnaud

    2016-01-01

    In three experiments, we investigated Hebb repetition learning (HRL) differences between children and adults, as a function of the type of item (lexical vs. sub-lexical) and the level of item-overlap between sequences. In a first experiment, it was shown that when non-repeating and repeating (Hebb) sequences of words were all permutations of the same words, HRL was slower than when the sequences shared no words. This item-overlap effect was observed in both children and adults. In a second experiment, we used syllable sequences and we observed reduced HRL due to item-overlap only in children. The findings are explained within a chunking account of the HRL effect on the basis of which we hypothesize that children, compared with adults, chunk syllable sequences in smaller units. By hypothesis, small chunks are more prone to interference from anagram representations included in the filler sequences, potentially explaining the item-overlap effect in children. This hypothesis was tested in a third experiment with adults where we experimentally manipulated the chunk size by embedding pauses in the syllable sequences. Interestingly, we showed that imposing a small chunk size caused adults to show the same behavioral effects as those observed in children. Departing from the analogy between verbal HRL and lexical development, the results are discussed in light of the less-is-more hypothesis of age-related differences in language acquisition. PMID:26779065

  19. Can model-free reinforcement learning explain deontological moral judgments?

    PubMed

    Ayars, Alisabeth

    2016-05-01

    Dual-systems frameworks propose that moral judgments are derived from both an immediate emotional response, and controlled/rational cognition. Recently Cushman (2013) proposed a new dual-system theory based on model-free and model-based reinforcement learning. Model-free learning attaches values to actions based on their history of reward and punishment, and explains some deontological, non-utilitarian judgments. Model-based learning involves the construction of a causal model of the world and allows for far-sighted planning; this form of learning fits well with utilitarian considerations that seek to maximize certain kinds of outcomes. I present three concerns regarding the use of model-free reinforcement learning to explain deontological moral judgment. First, many actions that humans find aversive from model-free learning are not judged to be morally wrong. Moral judgment must require something in addition to model-free learning. Second, there is a dearth of evidence for central predictions of the reinforcement account-e.g., that people with different reinforcement histories will, all else equal, make different moral judgments. Finally, to account for the effect of intention within the framework requires certain assumptions which lack support. These challenges are reasonable foci for future empirical/theoretical work on the model-free/model-based framework. PMID:26918742

  20. Scent marking in sifaka: no one function explains it all.

    PubMed

    Lewis, Rebecca J

    2006-06-01

    Various hypotheses to explain possible functions of scent-marking have been put forth and basically fall into five categories: territorial demarcation, ownership of resources, mate attraction, noncombative fighting, and self-advertisement. Verreaux's sifaka (Propithecus verreauxi verreauxi), like many prosimians, use scent-marking as one form of communication. The goal of this study was to determine the function of scent-marking in sifaka. All-occurrence of scent-marks, scent-mark context, and scent-mark style were collected on 23 sifaka in the Kirindy Forest of western Madagascar for 7 months (September 2001-March 2002). Scent-mark rates were collected using continuous focal animal sampling from November 2000-March 2002. Home range data were collected using monthly censuses and instantaneous focal sampling throughout the 17 months. Scent-marking behavior was exhibited almost exclusively by adults. Scent-mark rates were not related to the number of resident adult males, number of resident adult females, rank, or group size. The majority of scent-marks occurred in the perimeter of the home range; however, less than a quarter of the home range was used by only a single group. Sifaka did not preferentially mark food trees, mark during the mating season, or mark during intergroup encounters. The results from this study indicate that none of the five hypothesized functions best explains all scent-marking in Verreaux's sifaka. Rather, scent-marking may serve different functions for different individuals. PMID:16715510

  1. Dynamical models explaining social balance and evolution of cooperation.

    PubMed

    Traag, Vincent Antonio; Van Dooren, Paul; De Leenheer, Patrick

    2013-01-01

    Social networks with positive and negative links often split into two antagonistic factions. Examples of such a split abound: revolutionaries versus an old regime, Republicans versus Democrats, Axis versus Allies during the second world war, or the Western versus the Eastern bloc during the Cold War. Although this structure, known as social balance, is well understood, it is not clear how such factions emerge. An earlier model could explain the formation of such factions if reputations were assumed to be symmetric. We show this is not the case for non-symmetric reputations, and propose an alternative model which (almost) always leads to social balance, thereby explaining the tendency of social networks to split into two factions. In addition, the alternative model may lead to cooperation when faced with defectors, contrary to the earlier model. The difference between the two models may be understood in terms of the underlying gossiping mechanism: whereas the earlier model assumed that an individual adjusts his opinion about somebody by gossiping about that person with everybody in the network, we assume instead that the individual gossips with that person about everybody. It turns out that the alternative model is able to lead to cooperative behaviour, unlike the previous model. PMID:23634204

  2. Mackay icosahedron explaining orientation relationship of dispersoids in aluminium alloys.

    PubMed

    Muggerud, Astrid Marie F; Li, Yanjun; Holmestad, Randi; Andersen, Sigmund J

    2014-10-01

    The orientation relations (ORs) of the cubic icosahedral quasicrystal approximant phase α-Al(Fe,Mn)Si have been studied after low temperature annealing of a 3xxx wrought aluminium alloy by transmission electron microscopy. From diffraction studies it was verified that the most commonly observed OR for the α-Al(Fe,Mn)Si dispersoids is [1\\bar 11]α // [1\\bar 11]Al, (5\\bar 2\\bar 7)α // (011)Al. This orientation could be explained by assuming that the internal Mackay icosahedron (MI) in the α-phase has a fixed orientation in relation to Al, similar to that of the icosahedral quasi-crystals existing in this alloy system. It is shown that mirroring of the normal-to-high-symmetry icosahedral directions of the MI explains the alternative orientations, which are therefore likely to be caused by twinning of the fixed MI. Only one exception was found, which was related to the Bergman icosahedron internal to the T-phase of the Al-Mg-Zn system. PMID:25274523

  3. Explaining variance and identifying predictors of children's communication via a multilevel model of single-case design research.

    PubMed

    Ottley, Jennifer Riggie; Ferron, John M; Hanline, Mary Frances

    2016-06-01

    The purpose of this study was to explain the variability in data collected from a single-case design study and to identify predictors of communicative outcomes for children with developmental delays or disabilities (n = 4). Using SAS University Edition, we fit multilevel models with time nested within children. Children's initial levels of communication and teachers' frequency of strategy use when directed at the children predicted children's communicative outcomes. These results indicate that teachers' implementation of evidence-based communication strategies, when directed toward children with disabilities, and the interaction between their use of the strategies and children's initial levels of communication predict children's communicative outcomes. Implications for research and practice are provided. PMID:25825922

  4. Explaining Vegetable Consumption among Young Adults: An Application of the Theory of Planned Behaviour

    PubMed Central

    Menozzi, Davide; Sogari, Giovanni; Mora, Cristina

    2015-01-01

    Although fruit and vegetable consumption is highly recommended for a healthy and balanced daily diet, several European countries do not meet these recommendations. In Italy, only 45% of young people are consuming at least one portion of vegetables per day. Therefore, this paper aims to understand the main determinants of vegetables consumption among young adults to suggest possible intervention strategies. A cross-sectional study was conducted on a samples of Italian students (n = 751), using the theory of planned behaviour (TPB) as a conceptual framework. A structural equation model (SEM) was developed to test the TPB predictors for vegetable consumption, and the role of background factors (socio-demographic and personal characteristics) in improving the TPB model’s explaining power. Overall, 81% and 68%, respectively, of intentions and behaviour variance is explained by the TPB model. Socio-demographic and personal characteristics were found to influence intentions and behaviour indirectly by their effects on the theory’s more proximal determinants. Interventions should be targeted to improve perceived behavioural control (PBC), attitudes and subjective norms that significantly affect intentions. Tailored interventions for male students, enrolled in courses other than food science, and doing less physical activity may have a larger effect on behavioural change. PMID:26378570

  5. Explaining Vegetable Consumption among Young Adults: An Application of the Theory of Planned Behaviour.

    PubMed

    Menozzi, Davide; Sogari, Giovanni; Mora, Cristina

    2015-09-01

    Although fruit and vegetable consumption is highly recommended for a healthy and balanced daily diet, several European countries do not meet these recommendations. In Italy, only 45% of young people are consuming at least one portion of vegetables per day. Therefore, this paper aims to understand the main determinants of vegetables consumption among young adults to suggest possible intervention strategies. A cross-sectional study was conducted on a samples of Italian students (n = 751), using the theory of planned behaviour (TPB) as a conceptual framework. A structural equation model (SEM) was developed to test the TPB predictors for vegetable consumption, and the role of background factors (socio-demographic and personal characteristics) in improving the TPB model's explaining power. Overall, 81% and 68%, respectively, of intentions and behaviour variance is explained by the TPB model. Socio-demographic and personal characteristics were found to influence intentions and behaviour indirectly by their effects on the theory's more proximal determinants. Interventions should be targeted to improve perceived behavioural control (PBC), attitudes and subjective norms that significantly affect intentions. Tailored interventions for male students, enrolled in courses other than food science, and doing less physical activity may have a larger effect on behavioural change. PMID:26378570

  6. Synthesizing Strategies Creatively: Solving Linear Equations

    ERIC Educational Resources Information Center

    Ponce, Gregorio A.; Tuba, Imre

    2015-01-01

    New strategies can ignite teachers' imagination to create new lessons or adapt lessons created by others. In this article, the authors present the experience of an algebra teacher and his students solving linear and literal equations and explain how the use of ideas found in past NCTM journals helped bring this lesson to life. The…

  7. The Source for Learning & Memory Strategies.

    ERIC Educational Resources Information Center

    Richards, Regina G.

    This book is a comprehensive guide to learning and memory strategies for all students and especially those with learning problems. Chapter 1, on memory and the brain, explains brain cells, the cortex, function of the cerebral lobes, and other brain structures. Chapter 2 examines the memory process and discusses sensory memory, short-term memory,…

  8. Getting-Started Strategies and Cooperative Learning.

    ERIC Educational Resources Information Center

    Myers, John J.; And Others

    1991-01-01

    Offers several strategies for implementing cooperative learning in the classroom. Suggests sample exercises including (1) a scavenger hunt; (2) a reaction wheel; (3) cooperative brainstorming and classification; (4) a "pair of pairs" exercise; and (5) a three-step interview. Explains that the examples are starting points that have been used in…

  9. Commercial Crew Program Crew Safety Strategy

    NASA Technical Reports Server (NTRS)

    Vassberg, Nathan; Stover, Billy

    2015-01-01

    The purpose of this presentation is to explain to our international partners (ESA and JAXA) how NASA is implementing crew safety onto our commercial partners under the Commercial Crew Program. It will show them the overall strategy of 1) how crew safety boundaries have been established; 2) how Human Rating requirements have been flown down into programmatic requirements and over into contracts and partner requirements; 3) how CCP SMA has assessed CCP Certification and CoFR strategies against Shuttle baselines; 4) Discuss how Risk Based Assessment (RBA) and Shared Assurance is used to accomplish these strategies.

  10. Lymphangiogenesis may explain adrenal selectivity in lung cancer metastases.

    PubMed

    Onuigbo, Wilson I B

    2010-08-01

    The 'seed and soil' hypothesis of organ selectivity in cancer metastasis dated back to the 1870s. A century later, a review of significant selectivity data revealed that the adrenals featured in 11 of 12 classes of it, thus promoting these two organs for research. Fortunately, two discoveries have also occurred, namely, (a) that cancer stimulates lymph vessel formation, i.e., lymphangiogenesis, and (b) that lymph and blood vessels are differentially stainable. Accordingly, these interesting ideas should be exploited with a hypothesis. Therefore, it is proposed that, at autopsy in lung cancer cases, the tissues between the primary lung tumor and the adrenal secondary should be meticulously serially sectioned and disjunctively stained because they must reveal what naturally occurs in this zone during life. It is predicted that this maneuver will identify lymphangiogenesis as the phenomenon responsible for the age-old puzzle of adrenal selectivity. Indeed, it may explain other puzzles such as intracranial lymphatic connectivity. PMID:20303219

  11. EARTHSHINE ON A YOUNG MOON: EXPLAINING THE LUNAR FARSIDE HIGHLANDS

    SciTech Connect

    Roy, Arpita; Wright, Jason T.; Sigurðsson, Steinn

    2014-06-20

    The lunar farside highlands problem refers to the curious and unexplained fact that the farside lunar crust is thicker, on average, than the nearside crust. Here we recognize the crucial influence of Earthshine, and propose that it naturally explains this hemispheric dichotomy. Since the accreting Moon rapidly achieved synchronous rotation, a surface and atmospheric thermal gradient was imposed by the proximity of the hot, post-giant impact Earth. This gradient guided condensation of atmospheric and accreting material, preferentially depositing crust-forming refractories on the cooler farside, resulting in a primordial bulk chemical inhomogeneity that seeded the crustal asymmetry. Our model provides a causal solution to the lunar highlands problem: the thermal gradient created by Earthshine produced the chemical gradient responsible for the crust thickness dichotomy that defines the lunar highlands.

  12. Aerobic scope explains individual variation in feeding capacity.

    PubMed

    Auer, Sonya K; Salin, Karine; Anderson, Graeme J; Metcalfe, Neil B

    2015-11-01

    Links between metabolism and components of fitness such as growth, reproduction and survival can depend on food availability. A high standard metabolic rate (SMR; baseline energy expenditure) or aerobic scope (AS; the difference between an individual's maximum and SMR) is often beneficial when food is abundant or easily accessible but can be less important or even disadvantageous when food levels decline. While the mechanisms underlying these context-dependent associations are not well understood, they suggest that individuals with a higher SMR or AS are better able to take advantage of high food abundance. Here we show that juvenile brown trout (Salmo trutta) with a higher AS were able to consume more food per day relative to individuals with a lower AS. These results help explain why a high aerobic capacity can improve performance measures such as growth rate at high but not low levels of food availability. PMID:26556902

  13. Muon-Induced Neutrons Do Not Explain the DAMA Data.

    PubMed

    Klinger, J; Kudryavtsev, V A

    2015-04-17

    We present an accurate model of the muon-induced background in the DAMA/LIBRA experiment. Our work challenges proposed mechanisms which seek to explain the observed DAMA signal modulation with muon-induced backgrounds. Muon generation and transport are performed using the MUSIC/MUSUN code, and subsequent interactions in the vicinity of the DAMA detector cavern are simulated with Geant4. We estimate the total muon-induced neutron flux in the detector cavern to be Φ(n)(ν)=1.0 × 10(-9)  cm(-2) s(-1). We predict 3.49 × 10(-5)  counts/day/kg/keV, which accounts for less than 0.3% of the DAMA signal modulation amplitude. PMID:25933303

  14. Carbonatite ring-complexes explained by caldera-style volcanism.

    PubMed

    Andersson, Magnus; Malehmir, Alireza; Troll, Valentin R; Dehghannejad, Mahdieh; Juhlin, Christopher; Ask, Maria

    2013-01-01

    Carbonatites are rare, carbonate-rich magmatic rocks that make up a minute portion of the crust only, yet they are of great relevance for our understanding of crustal and mantle processes. Although they occur in all continents and from Archaean to present, the deeper plumbing system of carbonatite ring-complexes is usually poorly constrained. Here, we show that carbonatite ring-complexes can be explained by caldera-style volcanism. Our geophysical investigation of the Alnö carbonatite ring-complex in central Sweden identifies a solidified saucer-shaped magma chamber at ~3 km depth that links to surface exposures through a ring fault system. Caldera subsidence during final stages of activity caused carbonatite eruptions north of the main complex, providing the crucial element to connect plutonic and eruptive features of carbonatite magmatism. The way carbonatite magmas are stored, transported and erupt at the surface is thus comparable to known emplacement styles from silicic calderas. PMID:23591904

  15. The role of authority power in explaining procedural fairness effects.

    PubMed

    van Dijke, Marius; De Cremer, David; Mayer, David M

    2010-05-01

    Building on fairness heuristic theory, fairness theory, and trust development models, we argue that unfairly enacted procedures decrease followers' trust in the authority particularly when authorities have high power over their followers. Moreover, we expected trust to mediate procedural fairness effects on followers' attitudes (authorities' legitimacy and charisma attributed to authorities) and organizational citizenship behavior. Procedural fairness effects on these variables, as mediated by trust, should therefore also be stronger when authority power is high. The results of a single- and multisource field study and a laboratory experiment supported these predictions. These studies support the role of authority power as a theoretically and practically relevant moderator of procedural fairness effects and show that its effectiveness is explained through trust in authorities. PMID:20476828

  16. Social inheritance can explain the structure of animal social networks.

    PubMed

    Ilany, Amiyaal; Akçay, Erol

    2016-01-01

    The social network structure of animal populations has major implications for survival, reproductive success, sexual selection and pathogen transmission of individuals. But as of yet, no general theory of social network structure exists that can explain the diversity of social networks observed in nature, and serve as a null model for detecting species and population-specific factors. Here we propose a simple and generally applicable model of social network structure. We consider the emergence of network structure as a result of social inheritance, in which newborns are likely to bond with maternal contacts, and via forming bonds randomly. We compare model output with data from several species, showing that it can generate networks with properties such as those observed in real social systems. Our model demonstrates that important observed properties of social networks, including heritability of network position or assortative associations, can be understood as consequences of social inheritance. PMID:27352101

  17. Coordinated hydrolysis explains the mechanical behavior of kinesin.

    PubMed Central

    Peskin, C S; Oster, G

    1995-01-01

    The two-headed motor protein kinesin hydrolyzes nucleotide to move unidirectionally along its microtubule track at speeds up to 1000 nm/s (Saxton et al., 1988) and develops forces in excess of 5 pN (Hunt et al., 1994; Svoboda et al., 1994a). Individual kinesin molecules have been studied recently in vitro, and their behavior has been characterized in terms of force-velocity curves and variance measurements (Svoboda and Block, 1994a; Svoboda et al., 1994b). We present a model for force generation in kinesin in which the ATP hydrolysis reactions are coordinated with the relative positions of the two heads. The model explains the experimental data and permits us to study the relative roles of Brownian motion and elastic deformation in the motor mechanism of kinesin. Images FIGURE 1 FIGURE 2 FIGURE 3 PMID:7787069

  18. Carbonatite ring-complexes explained by caldera-style volcanism

    PubMed Central

    Andersson, Magnus; Malehmir, Alireza; Troll, Valentin R.; Dehghannejad, Mahdieh; Juhlin, Christopher; Ask, Maria

    2013-01-01

    Carbonatites are rare, carbonate-rich magmatic rocks that make up a minute portion of the crust only, yet they are of great relevance for our understanding of crustal and mantle processes. Although they occur in all continents and from Archaean to present, the deeper plumbing system of carbonatite ring-complexes is usually poorly constrained. Here, we show that carbonatite ring-complexes can be explained by caldera-style volcanism. Our geophysical investigation of the Alnö carbonatite ring-complex in central Sweden identifies a solidified saucer-shaped magma chamber at ~3 km depth that links to surface exposures through a ring fault system. Caldera subsidence during final stages of activity caused carbonatite eruptions north of the main complex, providing the crucial element to connect plutonic and eruptive features of carbonatite magmatism. The way carbonatite magmas are stored, transported and erupt at the surface is thus comparable to known emplacement styles from silicic calderas. PMID:23591904

  19. Can Personality Type Explain Heterogeneity in Probability Distortions?

    PubMed Central

    Capra, C. Monica; Jiang, Bing; Engelmann, Jan B.; Berns, Gregory S.

    2014-01-01

    There are two regularities we have learned from experimental studies of choice under risk. The first is that the majority of people weigh objective probabilities non-linearly. The second regularity, although less commonly acknowledged, is that there is a large amount of heterogeneity in how people distort probabilities. Despite of this, little effort has been made to identify the source of heterogeneity. In this paper, we explore the possibility that personality type is linked to probability distortions. Using validated psychological questionnaires, we clustered participants into distinct personality types: motivated, impulsive, and affective. We found that the motivated viewed gambling more attractive, whereas the impulsive were the most capable of discriminating non-extreme probabilities. Our results suggest that the observed heterogeneity in probability distortions may be explained by personality profiles, which can be elicited though standard psychological questionnaires. PMID:24639891

  20. Heterogeneity explains features of “anomalous” thermodynamics and statistics

    PubMed Central

    Gheorghiu, Stefan; Coppens, Marc-Olivier

    2004-01-01

    Phenomena characterized by power-law probability distributions abound in nature and the applied sciences. We show that many of these power laws are well described by the Student, or t, distribution, and we discuss the origin of this universality based on three examples (Brownian motion, Knudsen diffusion in rough pores, and bubbly multiphase flow). These case studies are representative for a large class of systems with heterogeneous features, examples of which can be found from Earth sciences to astrophysics, and even in the social sciences. We show that common forms of polydispersity, such as polydispersity arising naturally as a result of aggregation–fragmentation phenomena, typically lie at the basis of the observed scaling. We conclude that complicated arguments based on long-range correlations or nonergodicity are often incorrect or misleading in explaining many naturally observed power laws and, in particular, those described by the Student distribution. PMID:15514018

  1. Can Nomenclature for the Body be Explained by Embodiment Theories?

    PubMed

    Majid, Asifa; van Staden, Miriam

    2015-10-01

    According to widespread opinion, the meaning of body part terms is determined by salient discontinuities in the visual image; such that hands, feet, arms, and legs, are natural parts. If so, one would expect these parts to have distinct names which correspond in meaning across languages. To test this proposal, we compared three unrelated languages-Dutch, Japanese, and Indonesian-and found both naming systems and boundaries of even basic body part terms display variation across languages. Bottom-up cues alone cannot explain natural language semantic systems; there simply is not a one-to-one mapping of the body semantic system to the body structural description. Although body parts are flexibly construed across languages, body parts semantics are, nevertheless, constrained by non-linguistic representations in the body structural description, suggesting these are necessary, although not sufficient, in accounting for aspects of the body lexicon. PMID:26466949

  2. Microeconomic principles explain an optimal genome size in bacteria.

    PubMed

    Ranea, Juan A G; Grant, Alastair; Thornton, Janet M; Orengo, Christine A

    2005-01-01

    Bacteria can clearly enhance their survival by expanding their genetic repertoire. However, the tight packing of the bacterial genome and the fact that the most evolved species do not necessarily have the biggest genomes suggest there are other evolutionary factors limiting their genome expansion. To clarify these restrictions on size, we studied those protein families contributing most significantly to bacterial-genome complexity. We found that all bacteria apply the same basic and ancestral 'molecular technology' to optimize their reproductive efficiency. The same microeconomics principles that define the optimum size in a factory can also explain the existence of a statistical optimum in bacterial genome size. This optimum is reached when the bacterial genome obtains the maximum metabolic complexity (revenue) for minimal regulatory genes (logistic cost). PMID:15680509

  3. Exploring and Explaining Friction with the Prandtl-Tomlinson Model.

    PubMed

    Schwarz, Udo D; Hölscher, Hendrik

    2016-01-26

    The Prandtl-Tomlinson model of friction, first introduced in 1928 as a "conceptual model" for a single-atom contact, consists of a point mass that is dragged over a sinusoidal potential by a spring. After decades of virtual oblivion, it has recently found impressive validation for contacts comprising tens or even hundreds of atoms. To date, the Prandtl-Tomlinson model enjoys widespread popularity as depicting arguably the most insightful mechanical analogue to atomic-scale effects occurring at sliding interfaces. In this issue of ACS Nano, Pawlak et al. demonstrate the model's applicability to a true single-atom contact, thereby illustrating that simple mechanical representations can indeed go a long way toward explaining interactions at atomically defined interfaces. PMID:26765866

  4. Models explaining motor vehicle death rates in the United States.

    PubMed

    Zlatoper, T J

    1989-04-01

    This paper is a selective survey of models explaining motor vehicle death rates in the United States. First, it reviews Peltzman's 1975 study of the effect of automobile safety regulation and critiques of the study. Then it summarizes several subsequent statistical studies of highway fatalities. The surveyed studies are typically regression analyses of the impact of various factors on motor vehicle deaths. They are categorized in this paper according to which of three types of data they utilized: time-series; cross-sectional; or pooled time-series, cross-sectional. This paper notes what can be inferred collectively from the surveyed studies regarding the impacts of various factors on highway fatalities. It also discusses certain shortcomings of the studies in general along with possible remedies, and makes recommendations regarding future research. Tabular summaries of the statistical studies surveyed in this paper are included in the Appendix. PMID:2785390

  5. [To explain is to narrate. How to visualize scientific data].

    PubMed

    Hawtin, Nigel

    2014-01-01

    When you try to appeal a vast ranging audience, as it occurs at the New Scientist that addresses scientists as well as the general public, your scientific visual explainer must be succinct, clear, accurate and easily understandable. In order to reach this goal, your message should provide only the main data, the ones that allow you to balance information and clarity: information should be put into context and all the extra details should be cut down. It is very important, then, to know well both your audience and the subject you are going to describe, as graphic masters of the past, like William Playfair and Charles Minard, have taught us. Moreover, you should try to engage your reader connecting the storytelling power of words and the driving force of the graphics: colours, visual elements, typography. To be effective, in fact, an infographic should not only be truthful and functional, but also elegant, having style and legibility. PMID:25072540

  6. Explaining Society: An Expanded Toolbox for Social Scientists

    PubMed Central

    Bell, David C.; Atkinson-Schnell, Jodie L.; DiBacco, Aron E.

    2012-01-01

    We propose for social scientists a theoretical toolbox containing a set of motivations that neurobiologists have recently validated. We show how these motivations can be used to create a theory of society recognizably similar to existing stable societies (sustainable, self-reproducing, and largely peaceful). Using this toolbox, we describe society in terms of three institutions: economy (a source of sustainability), government (peace), and the family (reproducibility). Conducting a thought experiment in three parts, we begin with a simple theory with only two motivations. We then create successive theories that systematically add motivations, showing that each element in the toolbox makes its own contribution to explain the workings of a stable society and that the family has a critical role in this process. PMID:23082093

  7. Muon-Induced Neutrons Do Not Explain the DAMA Data

    NASA Astrophysics Data System (ADS)

    Klinger, J.; Kudryavtsev, V. A.

    2015-04-01

    We present an accurate model of the muon-induced background in the DAMA/LIBRA experiment. Our work challenges proposed mechanisms which seek to explain the observed DAMA signal modulation with muon-induced backgrounds. Muon generation and transport are performed using the MUSIC /MUSUN code, and subsequent interactions in the vicinity of the DAMA detector cavern are simulated with Geant4. We estimate the total muon-induced neutron flux in the detector cavern to be Φnν=1.0 ×10-9 cm-2 s-1 . We predict 3.49 ×10-5 counts /day /kg /keV , which accounts for less than 0.3% of the DAMA signal modulation amplitude.

  8. "Developmental capture" of the state: explaining Thailand's universal coverage policy.

    PubMed

    Harris, Joseph

    2015-02-01

    The notion of "regulatory capture" is typically used to describe the takeover of state agencies by outside interest groups that seek to weaken regulation and advance the agendas of interest groups through control over state policy levers. This concept can be contrasted with that of "developmental capture" of state agencies by networks of reformist bureaucrats within the state who seek to promote inclusive state social and developmental policies of benefit to the broader populace. Building on work that has pointed to instances in which state bureaucrats act autonomously from societal and political pressures, this article argues that existing explanations are insufficient for explaining Thailand's universal health care policy. It points to the critical role played by a network of bureaucrats within the state who strategically mobilized resources in the bureaucracy, political parties, civil society, and international organizations to institutionalize universal health care in the face of broader professional dissent, political uncertainty, and international pressure. PMID:25480847

  9. Explaining exercise behavior and satisfaction with social exchange theory.

    PubMed

    Unger, J; Johnson, C A

    1995-10-01

    This study tested the hypothesis that the variables specified by social exchange theory (perceived rewards of exercising, perceived costs of exercising, social and tangible investments, and available alternative activities) are associated with exercise behavior and satisfaction. 190 health club members completed a questionnaire assessing attitudes toward exercise, exercise behavior, and demographic information. Exercise frequency and satisfaction were regressed on the social exchange theory variables and demographic covariates. Exercise satisfaction, the number of investments in exercise, and the number of available alternative activities were significantly related to exercise frequency, and the number of perceived rewards of exercise and the number of investments were significantly related to exercise satisfaction. These results suggest that social exchange theory is useful for explaining exercise behavior. PMID:8570365

  10. Explaining social discrimination: racism in Brazil and xenophobia in Spain.

    PubMed

    Camino, Leoncio; Álvaro, José Luis; Torres, Ana Raquel R; Garrido, Alicia; Morais, Thiago; Barbosa, Juliana

    2013-01-01

    The present study investigates the arguments used by university students in order to explain social differences between social minorities and majorities. In Brazil, the issues investigated refer to White and Black people. In Spain, the reference is to native Spaniards and Moroccan immigrants. The participants were 144 Brazilians and 93 Spaniards, who answered a questionnaire composed of socio-demographic variables and one open question about the causes of social inequalities between Black and White people in Brazil and between autochthonous Spaniards and Moroccan Immigrants. A model is proposed to integrate the four discursive classes found using ALCESTE software. In Brazil, the strongest argument is based on the historical roots of the exploitation of Black people. In Spain, cultural differences are the main explanation for social inequalities. PMID:24230936

  11. Trophic network models explain instability of Early Triassic terrestrial communities

    PubMed Central

    Roopnarine, Peter D; Angielczyk, Kenneth D; Wang, Steve C; Hertog, Rachel

    2007-01-01

    Studies of the end-Permian mass extinction have emphasized potential abiotic causes and their direct biotic effects. Less attention has been devoted to secondary extinctions resulting from ecological crises and the effect of community structure on such extinctions. Here we use a trophic network model that combines topological and dynamic approaches to simulate disruptions of primary productivity in palaeocommunities. We apply the model to Permian and Triassic communities of the Karoo Basin, South Africa, and show that while Permian communities bear no evidence of being especially susceptible to extinction, Early Triassic communities appear to have been inherently less stable. Much of the instability results from the faster post-extinction diversification of amphibian guilds relative to amniotes. The resulting communities differed fundamentally in structure from their Permian predecessors. Additionally, our results imply that changing community structures over time may explain long-term trends like declining rates of Phanerozoic background extinction PMID:17609191

  12. Aerobic scope explains individual variation in feeding capacity

    PubMed Central

    Auer, Sonya K.; Salin, Karine; Anderson, Graeme J.; Metcalfe, Neil B.

    2015-01-01

    Links between metabolism and components of fitness such as growth, reproduction and survival can depend on food availability. A high standard metabolic rate (SMR; baseline energy expenditure) or aerobic scope (AS; the difference between an individual's maximum and SMR) is often beneficial when food is abundant or easily accessible but can be less important or even disadvantageous when food levels decline. While the mechanisms underlying these context-dependent associations are not well understood, they suggest that individuals with a higher SMR or AS are better able to take advantage of high food abundance. Here we show that juvenile brown trout (Salmo trutta) with a higher AS were able to consume more food per day relative to individuals with a lower AS. These results help explain why a high aerobic capacity can improve performance measures such as growth rate at high but not low levels of food availability. PMID:26556902

  13. Explaining prompts children to privilege inductively rich properties.

    PubMed

    Walker, Caren M; Lombrozo, Tania; Legare, Cristine H; Gopnik, Alison

    2014-11-01

    Four experiments with preschool-aged children test the hypothesis that engaging in explanation promotes inductive reasoning on the basis of shared causal properties as opposed to salient (but superficial) perceptual properties. In Experiments 1a and 1b, 3- to 5-year-old children prompted to explain during a causal learning task were more likely to override a tendency to generalize according to perceptual similarity and instead extend an internal feature to an object that shared a causal property. Experiment 2 replicated this effect of explanation in a case of label extension (i.e., categorization). Experiment 3 demonstrated that explanation improves memory for clusters of causally relevant (non-perceptual) features, but impairs memory for superficial (perceptual) features, providing evidence that effects of explanation are selective in scope and apply to memory as well as inference. In sum, our data support the proposal that engaging in explanation influences children's reasoning by privileging inductively rich, causal properties. PMID:25128793

  14. Quantitative experiments to explain the change of seasons

    NASA Astrophysics Data System (ADS)

    Testa, Italo; Busarello, Gianni; Puddu, Emanuella; Leccia, Silvio; Merluzzi, Paola; Colantonio, Arturo; Moretti, Maria Ida; Galano, Silvia; Zappia, Alessandro

    2015-03-01

    The science education literature shows that students have difficulty understanding what causes the seasons. Incorrect explanations are often due to a lack of knowledge about the physical mechanisms underlying this phenomenon. To address this, we present a module in which the students engage in quantitative measurements with a photovoltaic panel to explain changes to the sunray flow on Earth’s surface over the year. The activities also provide examples of energy transfers between the incoming radiation and the environment to introduce basic features of Earth’s climate. The module was evaluated with 45 secondary school students (aged 17-18) and a pre-/post-test research design. Analysis of students’ learning outcomes supports the effectiveness of the proposed activities.

  15. Jumping Jupiter Can Explain Mercury’s Orbit

    NASA Astrophysics Data System (ADS)

    Roig, Fernando; Nesvorný, David; DeSouza, Sandro Ricardo

    2016-04-01

    The orbit of Mercury has large values of eccentricity and inclination that cannot be easily explained if this planet formed on a circular and coplanar orbit. Here, we study the evolution of Mercury’s orbit during the instability related to the migration of the giant planets in the framework of the jumping-Jupiter model. We found that some instability models are able to produce the correct values of Mercury’s eccentricity and inclination, provided that relativistic effects are included in the precession of Mercury’s perihelion. The orbital excitation is driven by the fast change of the normal oscillation modes of the system corresponding to the perihelion precession of Jupiter (for the eccentricity) and the nodal regression of Uranus (for the inclination).

  16. Real world ocean rogue waves explained without the modulational instability.

    PubMed

    Fedele, Francesco; Brennan, Joseph; Ponce de León, Sonia; Dudley, John; Dias, Frédéric

    2016-01-01

    Since the 1990s, the modulational instability has commonly been used to explain the occurrence of rogue waves that appear from nowhere in the open ocean. However, the importance of this instability in the context of ocean waves is not well established. This mechanism has been successfully studied in laboratory experiments and in mathematical studies, but there is no consensus on what actually takes place in the ocean. In this work, we question the oceanic relevance of this paradigm. In particular, we analyze several sets of field data in various European locations with various tools, and find that the main generation mechanism for rogue waves is the constructive interference of elementary waves enhanced by second-order bound nonlinearities and not the modulational instability. This implies that rogue waves are likely to be rare occurrences of weakly nonlinear random seas. PMID:27323897

  17. Real world ocean rogue waves explained without the modulational instability

    PubMed Central

    Fedele, Francesco; Brennan, Joseph; Ponce de León, Sonia; Dudley, John; Dias, Frédéric

    2016-01-01

    Since the 1990s, the modulational instability has commonly been used to explain the occurrence of rogue waves that appear from nowhere in the open ocean. However, the importance of this instability in the context of ocean waves is not well established. This mechanism has been successfully studied in laboratory experiments and in mathematical studies, but there is no consensus on what actually takes place in the ocean. In this work, we question the oceanic relevance of this paradigm. In particular, we analyze several sets of field data in various European locations with various tools, and find that the main generation mechanism for rogue waves is the constructive interference of elementary waves enhanced by second-order bound nonlinearities and not the modulational instability. This implies that rogue waves are likely to be rare occurrences of weakly nonlinear random seas. PMID:27323897

  18. Social inheritance can explain the structure of animal social networks

    PubMed Central

    Ilany, Amiyaal; Akçay, Erol

    2016-01-01

    The social network structure of animal populations has major implications for survival, reproductive success, sexual selection and pathogen transmission of individuals. But as of yet, no general theory of social network structure exists that can explain the diversity of social networks observed in nature, and serve as a null model for detecting species and population-specific factors. Here we propose a simple and generally applicable model of social network structure. We consider the emergence of network structure as a result of social inheritance, in which newborns are likely to bond with maternal contacts, and via forming bonds randomly. We compare model output with data from several species, showing that it can generate networks with properties such as those observed in real social systems. Our model demonstrates that important observed properties of social networks, including heritability of network position or assortative associations, can be understood as consequences of social inheritance. PMID:27352101

  19. Using Literature-Based Discovery to Explain Adverse Drug Effects.

    PubMed

    Hristovski, Dimitar; Kastrin, Andrej; Dinevski, Dejan; Burgun, Anita; Žiberna, Lovro; Rindflesch, Thomas C

    2016-08-01

    We report on our research in using literature-based discovery (LBD) to provide pharmacological and/or pharmacogenomic explanations for reported adverse drug effects. The goal of LBD is to generate novel and potentially useful hypotheses by analyzing the scientific literature and optionally some additional resources. Our assumption is that drugs have effects on some genes or proteins and that these genes or proteins are associated with the observed adverse effects. Therefore, by using LBD we try to find genes or proteins that link the drugs with the reported adverse effects. These genes or proteins can be used to provide insight into the processes causing the adverse effects. Initial results show that our method has the potential to assist in explaining reported adverse drug effects. PMID:27318993

  20. Social Processes Explaining the Benefits of Al-Anon Participation

    PubMed Central

    Timko, Christine; Halvorson, Max; Kong, Calvin; Moos, Rudolf H

    2015-01-01

    This study examined social processes of support, goal direction, provision of role models, and involvement in rewarding activities to explain benefits of participating in Al-Anon, a 12-step mutual-help program for people concerned about another person’s substance use. Newcomers to Al-Anon were studied at baseline and 6 months later, when they were identified as having sustained attendance or dropped out. Among newcomers, and among established Al-Anon members (“oldtimers”), we also used number of Al-Anon meetings attended during follow-up to indicate extent of participation. Social processes significantly mediated between newcomers’ attendance status as sustained (versus dropped out) and outcomes of Al-Anon in the domains of life context (e.g., better quality of life, better able to handle problems due to the drinker), improved positive symptoms (more self-esteem, more hopeful), and decreased negative symptoms (e.g., less abuse, less depressed). Social processes also significantly mediated between newcomers’ number of meetings and outcomes. However, among oldtimers, Al-Anon attendance was not associated with outcomes, so the potential mediating role of social processes could not be examined, but social processes were associated with outcomes. Findings add to the growing body of work identifying mechanisms by which 12-step groups are effective, by showing that bonding, goal direction, and access to peers in recovery and rewarding pursuits help to explain associations between sustained Al-Anon participation among newcomers and improvements on key concerns of Al-Anon attendees. Al-Anon is free of charge and widely available, making it a potentially cost-effective public health resource in helping to alleviate negative consequences of concern about another’s addiction. PMID:26727006

  1. Strange history: the fall of Rome explained in Hereditas.

    PubMed

    Bengtsson, Bengt O

    2014-12-01

    In 1921 Hereditas published an article on the fall of Rome written by the famous classical scholar Martin P:son Nilsson. Why was a paper on this unexpected topic printed in the newly founded journal? To Nilsson, the demise of the Roman Empire was explained by the "bastardization" occurring between "races" from different parts of the realm. Offspring from mixed couples were of a less stable "type" than their parents, due to the breaking up by recombination of the original hereditary dispositions, which led to a general loss of competence to rule and govern. Thus, the "hardness" of human genes, together with their recombination, was - according to Nilsson - the main cause of the fall of Rome. Nilsson's argument is not particularly convincingly presented. Human "races" are taken to have the same genetic structure as inbred crop strains, and Nilsson believes in a metaphysical unity between the individual and the race to which it belongs. However, in my view, Martin P:son Nilsson and his friend Herman Nilsson-Ehle had wider aims with the article than to explain a historical event. The article can be read as indicating strong support from the classical human sciences to the ambitious new science of genetics. Support is also transferred from genetics to the conservative worldview, where the immutability and inflexibility of the Mendelian genes are used to strengthen the wish for greater stability in politics and life. The strange article in Hereditas can, thus, be read as an early instance in the - still ongoing - tug-of-war between the conservative and the liberal ideological poles over how genetic results best are socially interpreted. PMID:25588300

  2. Social processes explaining the benefits of Al-Anon participation.

    PubMed

    Timko, Christine; Halvorson, Max; Kong, Calvin; Moos, Rudolf H

    2015-12-01

    This study examined social processes of support, goal direction, provision of role models, and involvement in rewarding activities to explain benefits of participating in Al-Anon, a 12-step mutual-help program for people concerned about another person's substance use. Newcomers to Al-Anon were studied at baseline and 6 months later, at which time they were identified as having either sustained attendance or dropped out. Among both newcomers and established Al-Anon members ("old-timers"), we also used number of Al-Anon meetings attended during follow-up to indicate extent of participation. Social processes significantly mediated newcomers' sustained attendance status versus dropped out and outcomes of Al-Anon in the areas of life context (e.g., better quality of life, better able to handle problems due to the drinker), improved positive symptoms (e.g., higher self-esteem, more hopeful), and decreased negative symptoms (e.g., less abuse, less depressed). Social processes also significantly mediated newcomers' number of meetings attended and outcomes. However, among old-timers, Al-Anon attendance was not associated with outcomes, so the potential mediating role of social processes could not be examined, but social processes were associated with outcomes. Findings add to the growing body of work identifying mechanisms by which 12-step groups are effective, by showing that bonding, goal direction, and access to peers in recovery and rewarding pursuits help to explain associations between sustained Al-Anon participation among newcomers and improvements on key concerns of Al-Anon attendees. Al-Anon is free of charge and widely available, making it a potentially cost-effective public health resource for help alleviating negative consequences of concern about another's addiction. PMID:26727006

  3. Why Cosmic Fine-Tuning Needs to BE Explained

    NASA Astrophysics Data System (ADS)

    Manson, Neil Alan

    Discoveries in modern physics and Big Bang cosmology indicate that if either the initial conditions of the universe or the physical laws governing its development had differed even slightly, life could never have developed. It is for this reason that the universe is said to be ``fine-tuned'' for life. I argue that cosmic fine-tuning, which some want to dismiss as the way things just happen to be, in fact needs to be explained. In Chapter One I provide an overview of the evidence that the universe is fine-tuned for life. In Chapter Two I present a set of sufficient conditions for a fact's needing to be explained. The conditions are that the fact is improbable and that a ``tidy'' explanation of it is available. A tidy explanation of a fact is considerably less improbable than that fact and makes the obtaining of that fact considerably less improbable. Chapters Three, Four, and Five are devoted to showing that cosmic Chapter Three I argue that the universe's being finely tuned for life can meaningfully be considered improbable. In Chapter Four I claim that there is at least one tidy explanation of cosmic fine-tuning: that the universe was created by some sort of extramundane designer. In Chapters Four and Five I respond to three objections. The first is that the design hypothesis is ad hoc. The second is that we have no reason to believe a supernatural designer would prefer life-permitting cosmoi to other possible cosmoi and that our tendency to believe otherwise is the result of anthropocentrism. The third is that the design hypothesis never buys us an explanatory advantage.

  4. Modeling Chagas Disease at Population Level to Explain Venezuela's Real Data

    PubMed Central

    González-Parra, Gilberto; Chen-Charpentier, Benito M.; Bermúdez, Moises

    2015-01-01

    Objectives In this paper we present an age-structured epidemiological model for Chagas disease. This model includes the interactions between human and vector populations that transmit Chagas disease. Methods The human population is divided into age groups since the proportion of infected individuals in this population changes with age as shown by real prevalence data. Moreover, the age-structured model allows more accurate information regarding the prevalence, which can help to design more specific control programs. We apply this proposed model to data from the country of Venezuela for two periods, 1961–1971, and 1961–1991 taking into account real demographic data for these periods. Results Numerical computer simulations are presented to show the suitability of the age-structured model to explain the real data regarding prevalence of Chagas disease in each of the age groups. In addition, a numerical simulation varying the death rate of the vector is done to illustrate prevention and control strategies against Chagas disease. Conclusion The proposed model can be used to determine the effect of control strategies in different age groups. PMID:26929912

  5. Explaining the Kuiper Belt with a Jumping Planet

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-09-01

    A feature of the Kuiper Belt known as the kernel has yet to be adequately explained by solar system formation models. In a recent study, a theorist at the Southwest Research Institute proposes a new explanation for how Neptune arrived at its current orbit and how this planets migration in the early years of the solar system might have created the kernel.Orbital JumpThe kernel is a concentration of orbits within the Kuiper Belt that all have semimajor axes of roughly a 44 AU, low eccentricities, and low inclinations. How this collection of objects formed and why they exist where they do is difficult to explain with current models, however. Kernel objects arent in resonance with any of the larger bodies, so why are they concentrated at that specific distance? In this study, David Nesvorn proposes that the kernel resulted from Neptunes outward migration through the solar system.In the currently favored model of our solar systems formation, the outermost gas giant planets formed closer to the Sun and then migrated out to their current locations. Nesvorn ran a series of simulations of this migration to test the theory that a discontinuity in Neptunes movement outward i.e., a sudden jump in the planets orbital distance could explain the presence of the Kuiper Belts kernel.Results from a previous study, in which the authors evolved the four gas giant planets plus a fifth giant planet (blue) initially on an orbit between Saturn and Uranus. At 18.3 Myr, a close encounter with the fifth planet causes Neptunes orbit (pink) to jump outwards by ~0.4 AU, and the fifth planet is then ejected from the solar system by Jupiter. [Nesvorn 2015]Resonant PopulationNesvorn was successful in finding a model that reproduced the kernel, as well as other observed features of the solar system today. In his model, Neptune began its journey closer to the Sun, at a distance of roughly 24 AU, and it migrated fairly rapidly outward to about 28 AU. As it traveled, it swept up bodies in the outer

  6. Marketing strategy determinants in rural hospitals.

    PubMed

    Smith, H L; Haley, D; Piland, N F

    1993-01-01

    Rural hospitals confront an inauspicious environment due to changes in patient reimbursement and medical practice. Facing a situation of declining revenues, marketing presents an option for rural hospitals to adapt to the growing constraints. This paper analyzes the determinants of marketing strategy emphasis in rural hospitals. The conceptual model adopted in this study predicts that prior performance and contextual variables explain marketing strategy emphasis. The relationships are examined in a case study of rural New Mexico hospitals. Results suggest that prior performance and several contextual variables explain variations in marketing strategy emphasis. In particular, higher gross patient revenues are associated with more emphasis on television and radio advertising. Furthermore, rural New Mexico hospitals with high numbers of licensed beds and medical staff members, or that are affiliated with a chain organization, place greater emphasis on market research and market planning. The implications for marketing practice in rural hospitals are discussed. PMID:10135505

  7. Simple settlement decisions explain common dispersal patterns in territorial species.

    PubMed

    Gilroy, James J; Lockwood, Julie L

    2016-09-01

    Dispersal is one of the least-understood aspects of animal behaviour. For example, little is known of the mechanisms that determine how individuals express different dispersal behaviours in response to different circumstances. Uncovering these mechanisms is important for our understanding of spatial population dynamics. Using agent-based simulations, we examine how simple decision rules generate individual-level dispersal plasticity, and how this can influence population-scale dispersal dynamics. We model a territorial, monogamous population inhabiting a completely homogeneous environment. Dispersal variability therefore emerges solely as a result of between-individual interactions (competition, settlement, reproduction), which are governed by simple decision-making algorithms. We show that complex dispersal dynamics, including sex biases and strong density dependence, emerge naturally from simple rule-based behaviours. Dispersal is particularly sensitive to the inclusion of mate availability as a criterion for settlement: if neither sex evaluates mate availability, dispersal distances tend to decline at low densities, leading to a strong Allee effect from reduced pairing success. If one sex evaluates mate availability (females), Allee effects are largely avoided, but female-biased dispersal generates increasingly male-biased adult sex ratios at low densities. Sex biases are eliminated if both sexes evaluate mate availability, but population growth rates tend to be reduced due to survival costs and reduced pairing success. Our models suggest that simple decision mechanisms can explain several dynamic patterns that are commonly observed among territorial species. Importantly, these patterns emerge in the absence of environmental heterogeneity or between-individual variation in dispersal phenotypes, two conditions that are often invoked to explain dispersal heterogeneity in nature. This has implications for studies seeking to examine the causes of dispersal

  8. Knowledge cannot explain the developmental growth of working memory capacity.

    PubMed

    Cowan, Nelson; Ricker, Timothy J; Clark, Katherine M; Hinrichs, Garrett A; Glass, Bret A

    2015-01-01

    According to some views of cognitive growth, the development of working memory capacity can account for increases in the complexity of cognition. It has been difficult to ascertain, though, that there actually is developmental growth in capacity that cannot be attributed to other developing factors. Here we assess the role of item familiarity. We document developmental increases in working memory for visual arrays of English letters versus unfamiliar characters. Although letter knowledge played a special role in development between the ages of 6 and 8 years, children with adequate letter knowledge showed practically the same developmental growth in normalized functions for letters and unfamiliar characters. The results contribute to a growing body of evidence that the developmental improvement in working memory does not wholly stem from supporting processes such as encoding, mnemonic strategies, and knowledge. A video abstract is available at: https://www.youtube.com/watch?v=LJdqErLR2Hs&feature=youtu.be. PMID:24942111

  9. Knowledge Cannot Explain the Developmental Growth of Working Memory Capacity

    PubMed Central

    Cowan, Nelson; Ricker, Timothy J.; Clark, Katherine M.; Hinrichs, Garrett A.; Glass, Bret A.

    2014-01-01

    According to some views of cognitive growth, the development of working memory capacity can account for increases in the complexity of cognition. It has been difficult to ascertain, though, that there actually is developmental growth in capacity that cannot be attributed to other developing factors. Here we assess the role of item familiarity. We document developmental increases in working memory for visual arrays of English letters versus unfamiliar characters. Although letter knowledge played a special role in development between the ages of 6 to 8 years, children with adequate letter knowledge showed practically the same developmental growth in normalized functions for letters and unfamiliar characters. The results contribute to a growing body of evidence that the developmental improvement in working memory does not wholly stem from supporting processes such as encoding, mnemonic strategies, and knowledge. PMID:24942111

  10. Self-Talk: Strategies for Success in Math.

    ERIC Educational Resources Information Center

    Corral, Nadine; Antia, Shirin D.

    1997-01-01

    Discusses turning the mathematics failure cycle of students with learning disabilities into a success cycle by using learning strategies and positive attributions. Identifies eight steps to success with learning strategies are as well as six steps to positive attribution in math. The attribution theory is also explained. (CR)