Estimation of Indirect Effects in the Presence of Unmeasured Confounding for the Mediator-Outcome Relationship in a Multilevel 2-1-1 Mediation Model

Science.gov (United States)

Talloen, Wouter; Moerkerke, Beatrijs; Loeys, Tom; De Naeghel, Jessie; Van Keer, Hilde; Vansteelandt, Stijn

2016-01-01

To assess the direct and indirect effect of an intervention, multilevel 2-1-1 studies with intervention randomized at the upper (class) level and mediator and outcome measured at the lower (student) level are frequently used in educational research. In such studies, the mediation process may flow through the student-level mediator (the within…

Resource-Mediated Indirect Effects of Grassland Management on Arthropod Diversity

Science.gov (United States)

Simons, Nadja K.; Gossner, Martin M.; Lewinsohn, Thomas M.; Boch, Steffen; Lange, Markus; Müller, Jörg; Pašalić, Esther; Socher, Stephanie A.; Türke, Manfred; Fischer, Markus; Weisser, Wolfgang W.

2014-01-01

Intensive land use is a driving force for biodiversity decline in many ecosystems. In semi-natural grasslands, land-use activities such as mowing, grazing and fertilization affect the diversity of plants and arthropods, but the combined effects of different drivers and the chain of effects are largely unknown. In this study we used structural equation modelling to analyse how the arthropod communities in managed grasslands respond to land use and whether these responses are mediated through changes in resource diversity or resource quantity (biomass). Plants were considered resources for herbivores which themselves were considered resources for predators. Plant and arthropod (herbivores and predators) communities were sampled on 141 meadows, pastures and mown pastures within three regions in Germany in 2008 and 2009. Increasing land-use intensity generally increased plant biomass and decreased plant diversity, mainly through increasing fertilization. Herbivore diversity decreased together with plant diversity but showed no response to changes in plant biomass. Hence, land-use effects on herbivore diversity were mediated through resource diversity rather than quantity. Land-use effects on predator diversity were mediated by both herbivore diversity (resource diversity) and herbivore quantity (herbivore biomass), but indirect effects through resource quantity were stronger. Our findings highlight the importance of assessing both direct and indirect effects of land-use intensity and mode on different trophic levels. In addition to the overall effects, there were subtle differences between the different regions, pointing to the importance of regional land-use specificities. Our study underlines the commonly observed strong effect of grassland land use on biodiversity. It also highlights that mechanistic approaches help us to understand how different land-use modes affect biodiversity. PMID:25188423

An invasive plant promotes its arbuscular mycorrhizal symbioses and competitiveness through its secondary metabolites: indirect evidence from activated carbon.

Science.gov (United States)

Yuan, Yongge; Tang, Jianjun; Leng, Dong; Hu, Shuijin; Yong, Jean W H; Chen, Xin

2014-01-01

Secondary metabolites released by invasive plants can increase their competitive ability by affecting native plants, herbivores, and pathogens at the invaded land. Whether these secondary metabolites affect the invasive plant itself, directly or indirectly through microorganisms, however, has not been well documented. Here we tested whether activated carbon (AC), a well-known absorbent for secondary metabolites, affect arbuscular mycorrhizal (AM) symbioses and competitive ability in an invasive plant. We conducted three experiments (experiments 1-3) with the invasive forb Solidago canadensis and the native Kummerowia striata. Experiment 1 determined whether AC altered soil properties, levels of the main secondary metabolites in the soil, plant growth, and AMF communities associated with S. canadensis and K. striata. Experiment 2 determined whether AC affected colonization of S. canadensis by five AMF, which were added to sterilized soil. Experiment 3 determined the competitive ability of S. canadensis in the presence and absence of AMF and AC. In experiment 1, AC greatly decreased the concentrations of the main secondary metabolites in soil, and the changes in concentrations were closely related with the changes of AMF in S. canadensis roots. In experiment 2, AC inhibited the AMF Glomus versiforme and G. geosporum but promoted G. mosseae and G. diaphanum in the soil and also in S. canadensis roots. In experiment 3, AC reduced S. canadensis competitive ability in the presence but not in the absence of AMF. Our results provided indirect evidence that the secondary metabolites (which can be absorbed by AC) of the invasive plant S. canadensis may promote S. canadensis competitiveness by enhancing its own AMF symbionts.

Hapten design and indirect competitive immunoassay for parathion determination: Correlation with molecular modeling and principal component analysis

Energy Technology Data Exchange (ETDEWEB)

Liu Yihua [Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029 (China); Jin Maojun [Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029 (China); Gui Wenjun [Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029 (China); Cheng Jingli [Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029 (China); Guo Yirong [Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029 (China); Zhu Guonian [Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029 (China)]. E-mail: zhugn@zju.edu.cn

2007-05-22

A novel procedure for parathion hapten design is described. The optimal antigen for parathion was selected after molecular modeling studies of six types of potentially immunizing haptens with the aim to identify the best mimicking target analyte. Heterologous competitive indirect enzyme-linked immunosorbent assay (ELISA) was developed after screening a battery of competitors as coating antigens. The relationship between the heterology degree of the competitor and the resulting immunoassay detectability was investigated according to the electronic similarities of the competitor haptens and the target analyte. Molecular modeling and principal component analysis were performed to understand the electronic distribution and steric parameters of the haptens at their minimum energetic levels. The results suggested that the competitors should have a high heterology to produce assays with good detectability values. An indirect competitive ELISA was finally selected for further investigation. The immunoassay had an IC{sub 50} value of 4.79 ng mL{sup -1} and a limit of detection of 0.31 ng mL{sup -1}. There was little or no cross-reactivity to similar compounds tested except for the insecticide parathion-methyl, which showed a cross-reactivity of 7.8%.

Interspecific interactions in phytophagous insects revisited: a quantitative assessment of competition theory.

Science.gov (United States)

Kaplan, Ian; Denno, Robert F

2007-10-01

The importance of interspecific competition is a highly controversial and unresolved issue for community ecology in general, and for phytophagous insects in particular. Recent advancements, however, in our understanding of indirect (plant- and enemy-mediated) interactions challenge the historical paradigms of competition. Thus, in the context of this rapidly developing field, we re-evaluate the evidence for interspecific competition in phytophagous insects using a meta-analysis of published studies. Our analysis is specifically designed to test the assumptions underlying traditional competition theory, namely that competitive interactions are symmetrical, necessitate spatial and temporal co-occurrence, and increase in intensity as the density, phylogenetic similarity, and niche overlap of competing species increase. Despite finding frequent evidence for competition, we found very little evidence that plant-feeding insects conform to theoretical predictions for interspecific competition. Interactions were highly asymmetrical, similar in magnitude within vs. between feeding guilds (chewers vs. sap-feeders), and were unaffected by the quantity of resources removed (% defoliation). There was mixed support for the effects of phylogeny, spatial/temporal separation, and the relative strength of intra- vs. interspecific competition. Clearly, a new paradigm that accounts for indirect interactions and facilitation is required to describe how interspecific competition contributes to the organization of phytophagous insect communities, and perhaps to other plant and animal communities as well.

Small Firm Adaptive Capability, Competitive Strategy and Performance Outcomes: Competing Mediation vs Moderation Perspectives

OpenAIRE

Chryssochoidis, George; Dousios, Dimitrios; Tzokas, Nikolaos

2016-01-01

In small firms, adaptive capability exercises a handling grip on competitive strategy for superior performance primarily acting as a mediator and may offset, through attenuation, the adverse impact of limited resources. Besides exercising a handling grip on competitive strategy adaptive capability is more important than competitive strategy per se for superior performance. Adaptive capability simultaneously undertakes additional secondary roles reinforcing innovation competitive strategy for ...

An invasive plant promotes its arbuscular mycorrhizal symbioses and competitiveness through its secondary metabolites: indirect evidence from activated carbon.

Directory of Open Access Journals (Sweden)

Yongge Yuan

Full Text Available Secondary metabolites released by invasive plants can increase their competitive ability by affecting native plants, herbivores, and pathogens at the invaded land. Whether these secondary metabolites affect the invasive plant itself, directly or indirectly through microorganisms, however, has not been well documented. Here we tested whether activated carbon (AC, a well-known absorbent for secondary metabolites, affect arbuscular mycorrhizal (AM symbioses and competitive ability in an invasive plant. We conducted three experiments (experiments 1-3 with the invasive forb Solidago canadensis and the native Kummerowia striata. Experiment 1 determined whether AC altered soil properties, levels of the main secondary metabolites in the soil, plant growth, and AMF communities associated with S. canadensis and K. striata. Experiment 2 determined whether AC affected colonization of S. canadensis by five AMF, which were added to sterilized soil. Experiment 3 determined the competitive ability of S. canadensis in the presence and absence of AMF and AC. In experiment 1, AC greatly decreased the concentrations of the main secondary metabolites in soil, and the changes in concentrations were closely related with the changes of AMF in S. canadensis roots. In experiment 2, AC inhibited the AMF Glomus versiforme and G. geosporum but promoted G. mosseae and G. diaphanum in the soil and also in S. canadensis roots. In experiment 3, AC reduced S. canadensis competitive ability in the presence but not in the absence of AMF. Our results provided indirect evidence that the secondary metabolites (which can be absorbed by AC of the invasive plant S. canadensis may promote S. canadensis competitiveness by enhancing its own AMF symbionts.

Sperm competition risk drives rapid ejaculate adjustments mediated by seminal fluid.

Science.gov (United States)

Bartlett, Michael J; Steeves, Tammy E; Gemmell, Neil J; Rosengrave, Patrice C

2017-10-31

In many species, males can make rapid adjustments to ejaculate performance in response to sperm competition risk; however, the mechanisms behind these changes are not understood. Here, we manipulate male social status in an externally fertilising fish, chinook salmon ( Oncorhynchus tshawytscha ), and find that in less than 48 hr, males can upregulate sperm velocity when faced with an increased risk of sperm competition. Using a series of in vitro sperm manipulation and competition experiments, we show that rapid changes in sperm velocity are mediated by seminal fluid and the effect of seminal fluid on sperm velocity directly impacts paternity share and therefore reproductive success. These combined findings, completely consistent with sperm competition theory, provide unequivocal evidence that sperm competition risk drives plastic adjustment of ejaculate quality, that seminal fluid harbours the mechanism for the rapid adjustment of sperm velocity and that fitness benefits accrue to males from such adjustment.

Magnitude and Mechanism of Siderophore-Mediated Competition at Low Iron Solubility in the Pseudomonas aeruginosa Pyochelin System

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Konstanze T. Schiessl

2017-10-01

Full Text Available A central question in microbial ecology is whether microbial interactions are predominantly cooperative or competitive. The secretion of siderophores, microbial iron chelators, is a model system for cooperative interactions. However, siderophores have also been shown to mediate competition by sequestering available iron and making it unavailable to competitors. The details of how siderophores mediate competition are not well understood, especially considering the complex distribution of iron phases in the environment. One pertinent question is whether sequestering iron through siderophores can indeed be effective in natural conditions; many natural environments are characterized by large pools of precipitated iron, and it is conceivable that any soluble iron that is sequestered by siderophores is replenished by the dissolution of these precipitated iron sources. Our goal here was to address this issue, and investigate the magnitude and mechanism of siderophore-mediated competition in the presence of precipitated iron. We combined experimental work with thermodynamic modeling, using Pseudomonas aeruginosa as a model system and ferrihydrite precipitates as the iron source with low solubility. Our experiments show that competitive growth inhibition by the siderophore pyochelin is indeed efficient, and that inhibition of a competitor can even have a stronger growth-promoting effect than solubilization of precipitated iron. Based on the results of our thermodynamic models we conclude that the observed inhibition of a competitor is effective because sequestered iron is only very slowly replenished by the dissolution of precipitated iron. Our research highlights the importance of competitive benefits mediated by siderophores, and underlines that the dynamics of siderophore production and uptake in environmental communities could be a signature of competitive, not just cooperative, dynamics.

Magnitude and Mechanism of Siderophore-Mediated Competition at Low Iron Solubility in the Pseudomonas aeruginosa Pyochelin System.

Science.gov (United States)

Schiessl, Konstanze T; Janssen, Elisabeth M-L; Kraemer, Stephan M; McNeill, Kristopher; Ackermann, Martin

2017-01-01

A central question in microbial ecology is whether microbial interactions are predominantly cooperative or competitive. The secretion of siderophores, microbial iron chelators, is a model system for cooperative interactions. However, siderophores have also been shown to mediate competition by sequestering available iron and making it unavailable to competitors. The details of how siderophores mediate competition are not well understood, especially considering the complex distribution of iron phases in the environment. One pertinent question is whether sequestering iron through siderophores can indeed be effective in natural conditions; many natural environments are characterized by large pools of precipitated iron, and it is conceivable that any soluble iron that is sequestered by siderophores is replenished by the dissolution of these precipitated iron sources. Our goal here was to address this issue, and investigate the magnitude and mechanism of siderophore-mediated competition in the presence of precipitated iron. We combined experimental work with thermodynamic modeling, using Pseudomonas aeruginosa as a model system and ferrihydrite precipitates as the iron source with low solubility. Our experiments show that competitive growth inhibition by the siderophore pyochelin is indeed efficient, and that inhibition of a competitor can even have a stronger growth-promoting effect than solubilization of precipitated iron. Based on the results of our thermodynamic models we conclude that the observed inhibition of a competitor is effective because sequestered iron is only very slowly replenished by the dissolution of precipitated iron. Our research highlights the importance of competitive benefits mediated by siderophores, and underlines that the dynamics of siderophore production and uptake in environmental communities could be a signature of competitive, not just cooperative, dynamics.

Relationship between corporate social responsibility and competitive performance in Spanish SMEs: Empirical evidence from a stakeholders’ perspective

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Jesús Herrera Madueño

2016-01-01

Full Text Available In a financial economic scenario in which the corporate survival of small and medium enterprises (SMEs is more conditioned than ever by competitive performance, this paper aims to show that the strategic incorporation of socially responsible actions, more concerned and engaged with stakeholders, contributes to improve the competitiveness of these organizations. Thus, the existence of a direct or mediated relationship between the development of Corporate Social Responsibility (CSR practices and competitive performance has been analyzed from a multi-stakeholder perspective. To accomplish this task, data were collected from a sample of 481 Spanish SMEs and the technique of partial least squares (PLS was used. Outcomes show that the development of CSR practices contributes to increase the competitive performance both directly and indirectly, through the ability of these organizations to manage their stakeholders. This study, therefore, supports the social impact hypothesis and offers evidence about some intangibles such as the relational capacity mediate the causal effect between CSR and competitive performance.

From Hitting to Tattling to Gossip: An Evolutionary Rationale for the Development of Indirect Aggression

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Gordon P. D. Ingram

2014-04-01

Full Text Available Adult humans are characterized by low rates of intra-group physical aggression. Since children tend to be more physically aggressive, an evolutionary developmental account shows promise for explaining how physical aggression is suppressed in adults. I argue that this is achieved partly through extended dominance hierarchies, based on indirect reciprocity and linguistic transmission of reputational information, mediated by indirectly aggressive competition. Reviewing the literature on indirect and related forms of aggression provides three pieces of evidence for the claim that evolutionarily old impulses towards physical aggression are socialized into indirect aggression in humans: (i physical aggression falls in early childhood over the same age range at which indirect aggression increases; (ii the same individuals engage in both direct and indirect aggression; and (iii socially dominant individuals practice indirect aggression more frequently. Consideration of the developmental course of indirect aggression is complemented by analysis of similar developments in verbal behaviors that are not always thought of as aggressive, namely tattling and gossip. An important puzzle concerns why indirect aggression becomes more covert, and tattling more derogated, in preadolescence and adolescence. This may be due to the development of new strategies aimed at renegotiating social identity and friendship alliances in the peer group.

From hitting to tattling to gossip: an evolutionary rationale for the development of indirect aggression.

Science.gov (United States)

Ingram, Gordon P D

2014-04-29

Adult humans are characterized by low rates of intra-group physical aggression. Since children tend to be more physically aggressive, an evolutionary developmental account shows promise for explaining how physical aggression is suppressed in adults. I argue that this is achieved partly through extended dominance hierarchies, based on indirect reciprocity and linguistic transmission of reputational information, mediated by indirectly aggressive competition. Reviewing the literature on indirect and related forms of aggression provides three pieces of evidence for the claim that evolutionarily old impulses towards physical aggression are socialized into indirect aggression in humans: (i) physical aggression falls in early childhood over the same age range at which indirect aggression increases; (ii) the same individuals engage in both direct and indirect aggression; and (iii) socially dominant individuals practice indirect aggression more frequently. Consideration of the developmental course of indirect aggression is complemented by analysis of similar developments in verbal behaviors that are not always thought of as aggressive, namely tattling and gossip. An important puzzle concerns why indirect aggression becomes more covert, and tattling more derogated, in preadolescence and adolescence. This may be due to the development of new strategies aimed at renegotiating social identity and friendship alliances in the peer group.

Direct and Indirect Effects of Five Factor Personality and Gender on Depressive Symptoms Mediated by Perceived Stress

Science.gov (United States)

Kim, Song E.; Cho, Juhee; Kwon, Min-Jung; Chang, Yoosoo; Ryu, Seungho; Shin, Hocheol

2016-01-01

This study was designed to investigate associations among five factor personality traits, perceived stress, and depressive symptoms and to examine the roles of personality and perceived stress in the relationship between gender and depressive symptoms. The participants (N = 3,950) were part of a cohort study for health screening and examination at the Kangbuk Samsung Hospital. Personality was measured with the Revised NEO Personality Inventory (NEO-PI-R). Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D). Perceived stress level was evaluated with a self-reported stress questionnaire developed for the Korea National Health and Nutrition Examination Survey. A higher degree of neuroticism and lower degrees of extraversion, agreeableness, and conscientiousness were significantly associated with greater perceived stress and depressive symptoms. Neuroticism and extraversion had significant direct and indirect effects (via stress as a mediator) on depressive symptoms in both genders. Agreeableness and conscientiousness had indirect effects on depression symptoms in both genders. Multiple mediation models were used to examine the mediational roles of each personality factor and perceived stress in the link between gender and depressive symptoms. Four of the personality factors (except openness) were significant mediators, along with stress, on the relationship between gender and depressive symptoms. Our findings suggest that the links between personality factors and depressive symptoms are mediated by perceived stress. As such, personality is an important factor to consider when examining the link between gender and depression. PMID:27120051

Direct and Indirect Effects of Five Factor Personality and Gender on Depressive Symptoms Mediated by Perceived Stress.

Science.gov (United States)

Kim, Song E; Kim, Han-Na; Cho, Juhee; Kwon, Min-Jung; Chang, Yoosoo; Ryu, Seungho; Shin, Hocheol; Kim, Hyung-Lae

2016-01-01

This study was designed to investigate associations among five factor personality traits, perceived stress, and depressive symptoms and to examine the roles of personality and perceived stress in the relationship between gender and depressive symptoms. The participants (N = 3,950) were part of a cohort study for health screening and examination at the Kangbuk Samsung Hospital. Personality was measured with the Revised NEO Personality Inventory (NEO-PI-R). Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D). Perceived stress level was evaluated with a self-reported stress questionnaire developed for the Korea National Health and Nutrition Examination Survey. A higher degree of neuroticism and lower degrees of extraversion, agreeableness, and conscientiousness were significantly associated with greater perceived stress and depressive symptoms. Neuroticism and extraversion had significant direct and indirect effects (via stress as a mediator) on depressive symptoms in both genders. Agreeableness and conscientiousness had indirect effects on depression symptoms in both genders. Multiple mediation models were used to examine the mediational roles of each personality factor and perceived stress in the link between gender and depressive symptoms. Four of the personality factors (except openness) were significant mediators, along with stress, on the relationship between gender and depressive symptoms. Our findings suggest that the links between personality factors and depressive symptoms are mediated by perceived stress. As such, personality is an important factor to consider when examining the link between gender and depression.

Direct and Indirect Influence of Non-Native Neighbours on Pollination and Fruit Production of a Native Plant.

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Ana Montero-Castaño

Full Text Available Entomophilous non-native plants can directly affect the pollination and reproductive success of native plant species and also indirectly, by altering the composition and abundance of floral resources in the invaded community. Separating direct from indirect effects is critical for understanding the mechanisms underlying the impacts of non-native species on recipient communities.Our aims are: (a to explore both the direct effect of the non-native Hedysarum coronarium and its indirect effect, mediated by the alteration of floral diversity, on the pollinator visitation rate and fructification of the native Leopoldia comosa and (b to distinguish whether the effects of the non-native species were due to its floral display or to its vegetative interactions.We conducted field observations within a flower removal experimental setup (i.e. non-native species present, absent and with its inflorescences removed at the neighbourhood scale.Our study illustrates the complexity of mechanisms involved in the impacts of non-native species on native species. Overall, Hedysarum increased pollinator visitation rates to Leopoldia target plants as a result of direct and indirect effects acting in the same direction. Due to its floral display, Hedysarum exerted a direct magnet effect attracting visits to native target plants, especially those made by the honeybee. Indirectly, Hedysarum also increased the visitation rate of native target plants. Due to the competition for resources mediated by its vegetative parts, it decreased floral diversity in the neighbourhoods, which was negatively related to the visitation rate to native target plants. Hedysarum overall also increased the fructification of Leopoldia target plants, even though such an increase was the result of other indirect effects compensating for the observed negative indirect effect mediated by the decrease of floral diversity.

Direct and indirect associations between social anxiety and nicotine dependence and cessation problems: multiple mediator analyses.

Science.gov (United States)

Buckner, Julia D; Farris, Samantha G; Schmidt, Norman B; Zvolensky, Michael J

2014-06-01

Little empirical work has evaluated why socially anxious smokers are especially vulnerable to more severe nicotine dependence and cessation failure. Presumably, these smokers rely on cigarettes to help them manage their chronically elevated negative affect elicited by a wide array of social contexts. The current study examined the direct and indirect effects of social anxiety cross-sectionally in regard to a range of smoking processes among 466 treatment-seeking smokers. Negative affect and negative affect reduction motives were examined as mediators of the relations of social anxiety with nicotine dependence and cessation problems. Social anxiety was directly and robustly associated with perceived barriers to smoking cessation and problems experienced during past quit attempts. Social anxiety was also associated with greater nicotine dependence and smoking inflexibility indirectly through negative affect and negative affect smoking motives. Negative affect and smoking to reduce negative affect mediated these relations. These findings document the important role of negative affect and negative affect reduction motives in the relationships of social anxiety with nicotine dependence and cessation problems.

Does the European natural gas market pass the competitive benchmark of the theory of storage? Indirect tests for three major trading points

International Nuclear Information System (INIS)

Stronzik, Marcus; Rammerstorfer, Margarethe; Neumann, Anne

2009-01-01

This paper presents the first comparative analysis of the relationship between natural gas storage utilization and price patterns at three major European trading points. Using two indirect tests developed by that are applied in other commodity markets, we impose the no arbitrage condition to model the efficiency of the natural gas market. The results reveal that while operators of European storage facilities realize seasonal arbitrage profits, substantial arbitrage potentials remain. We suggest that the indirect approach is well suited to provide market insights for periods with limited data. We find that overall market performance differs substantially from the competitive benchmark of the theory of storage. (author)

Majorana Dark Matter with a Coloured Mediator: Collider vs Direct and Indirect Searches

CERN Document Server

Garny, Mathias; Rydbeck, Sara; Vogl, Stefan

2014-01-01

We investigate the signatures at the Large Hadron Collider of a minimal model where the dark matter particle is a Majorana fermion that couples to the Standard Model via one or several coloured mediators. We emphasize the importance of the production channel of coloured scalars through the exchange of a dark matter particle in the t-channel, and perform a dedicated analysis of searches for jets and missing energy for this model. We find that the collider constraints are highly competitive compared to direct detection, and can even be considerably stronger over a wide range of parameters. We also discuss the complementarity with searches for spectral features at gamma-ray telescopes and comment on the possibility of several coloured mediators, which is further constrained by flavour observables.

Majorana dark matter with a coloured mediator. Collider vs direct and indirect searches

International Nuclear Information System (INIS)

Garny, Mathias

2014-03-01

We investigate the signatures at the Large Hadron Collider of a minimal model where the dark matter particle is a Majorana fermion that couples to the Standard Model via one or several coloured mediators. We emphasize the importance of the production channel of coloured scalars through the exchange of a dark matter particle in the t-channel, and perform a dedicated analysis of searches for jets and missing energy for this model. We find that the collider constraints are highly competitive compared to direct detection, and can even be considerably stronger over a wide range of parameters. We also discuss the complementarity with searches for spectral features at gamma-ray telescopes and comment on the possibility of several coloured mediators, which is further constrained by flavour observables.

Sources of sport confidence, imagery type and performance among competitive athletes: the mediating role of sports confidence.

Science.gov (United States)

Levy, A R; Perry, J; Nicholls, A R; Larkin, D; Davies, J

2015-01-01

This study explored the mediating role of sport confidence upon (1) sources of sport confidence-performance relationship and (2) imagery-performance relationship. Participants were 157 competitive athletes who completed state measures of confidence level/sources, imagery type and performance within one hour after competition. Among the current sample, confirmatory factor analysis revealed appropriate support for the nine-factor SSCQ and the five-factor SIQ. Mediational analysis revealed that sport confidence had a mediating influence upon the achievement source of confidence-performance relationship. In addition, both cognitive and motivational imagery types were found to be important sources of confidence, as sport confidence mediated imagery type- performance relationship. Findings indicated that athletes who construed confidence from their own achievements and report multiple images on a more frequent basis are likely to benefit from enhanced levels of state sport confidence and subsequent performance.

Field trial of brucellosis competitive ELISA

International Nuclear Information System (INIS)

Perez, B.; Rojas, M.

1998-01-01

2990 sera samples from cattle were tested for antibodies to Brucella abortus using 8 serological tests for. The tests used were Rose Bengal (RBT), Buffer Plate Agglutination Test (BPAT), Complement Fixation (CFT), 2 Indirect and 2 Competitive Enzyme Linked Immunosorbent Assays (ELISA). Bacteriological evaluation from milk was done also. All tests were compared with respect to diagnostic specificity in vaccinated herds which were considered to be Brucella-free. The diagnostic specificity of the Indirect and Competitive ELISA was greater than 99,8%. Estimates of relative sensitivity were obtained from infected herds. The diagnostic sensitivity of the Indirect ELISA was greater than 95,8% and for the Competitive ELISA between 98,8 and 100 %, the last value refers to the Competitive ELISA Prototype II (SLPS antigen/M84 Mab), which was found highly suitable to differentiate vaccinated from brucella-infected cattle. The use of C-ELISA II for monitoring bovine populations under an eradication programme is recommended. (author)

Mediator Effect of TPM between TQM and Business Performance in Malaysia Automotive Industry

Science.gov (United States)

Ahmad, M. F.; Zakuan, N.; Rasi, Raja Zuraidah R. M.; Hisyamudin, M. N. N.

2015-05-01

Total Quality Management (TQM) is vital management tool in ensuring a company can success in the continuously growing competition in the global market. In order to survive in the global market with intense competition amongst regions and enterprises, the adoption of tools and techniques are essential in improving business performance. However, only few previous studies have examined the mediators and moderators between TQM and business performance. This present research proposed a TQM performance model with mediator effect of TPM with structural equation modelling, which is a more comprehensive model for developing countries, specifically for Malaysia. A questionnaire was prepared and sent to 1500 companies from automotive industry and the related vendors in Malaysia, giving a 21.3 per cent rate. The result concludes that TPM is partial mediation between and TQM and Business Performance with indirect effect (IE) is 0.25 which can be categorised as high mediator effect.

Trait and perceived environmental competitiveness in achievement situations.

Science.gov (United States)

Elliot, Andrew J; Jury, Mickaël; Murayama, Kou

2018-06-01

Trait and perceived environmental competitiveness are typically studied separately, but they undoubtedly have a joint influence on goal pursuit and behavior in achievement situations. The present research was designed to study them together. We tested the relation between trait and perceived environmental competitiveness, and we tested these variables as separate and sequential predictors of both performance-based goals and performance attainment. In Studies 1a (N = 387 U.S. undergraduates) and 1b (N = 322 U.S. undergraduates), we assessed participants' trait and perceived environmental competitiveness, as well as third variable candidates. In Study 2 (N = 434 MTurk workers), we sought to replicate and extend Study 1 by adding reports of performance-based goal pursuit. In Study 3 (N = 403 U.S. undergraduates), we sought to replicate and extend Study 2 by adding real-world performance attainment. The studies focused on both the classroom and the workplace. Trait and perceived environmental competitiveness were shown to be positively related and to positively predict separate variance in performance-approach and performance-avoidance goal pursuit. Perceived environmental competitiveness and performance-based goal pursuit were shown to be sequential mediators of the indirect relation between trait competitiveness and performance attainment. These studies highlight the importance of attending to the interplay of the person and the (perceived) situation in analyses of competitive striving. © 2017 Wiley Periodicals, Inc.

Theoretical aspects of competitive advantage and competition

OpenAIRE

Hudakova, Ivana

2009-01-01

The concept of competitive advantage is well-known for many of us and a number of literary resources focused on entrepreneurship and functioning of economies deal with it, either directly or indirectly. The understanding of the term competitive advantage though sometimes varies. One can only perceive it when looking at it as a whole, a live organism that is constantly developing in a complex dynamic entrepreneurial environment, the individual parts of which do not function when separated from...

On the Relative Size of Direct and Indirect Taxation

OpenAIRE

Soldatos, Gerasimos T.

2014-01-01

Modifying the standard analytical apparatuses for direct and indirect tax evasion to incorporate forward indirect tax shift in a monopolistically competitive environment, this paper maintains that indirect tax evasion would exceed for sure direct tax evasion only under consumer risk neutrality and a tax policy zeroing the tax shift. Also, in the presence of tax evasion, there cannot be optimal direct-indirect tax mix, because tax evasion is accompanied by uncertainty and hence, nonlinearities...

Aptamer-mediated indirect quantum dot labeling and fluorescent imaging of target proteins in living cells

International Nuclear Information System (INIS)

Liu, Jianbo; Zhang, Pengfei; Yang, Xiaohai; Wang, Kemin; Guo, Qiuping; Huang, Jin; Li, Wei

2014-01-01

Protein labeling for dynamic living cell imaging plays a significant role in basic biological research, as well as in clinical diagnostics and therapeutics. We have developed a novel strategy in which the dynamic visualization of proteins within living cells is achieved by using aptamers as mediators for indirect protein labeling of quantum dots (QDs). With this strategy, the target protein angiogenin was successfully labeled with fluorescent QDs in a minor intactness model, which was mediated by the aptamer AL6-B. Subsequent living cell imaging analyses indicated that the QDs nanoprobes were selectively bound to human umbilical vein endothelial cells, gradually internalized into the cytoplasm, and mostly localized in the lysosome organelle, indicating that the labeled protein retained high activity. Compared with traditional direct protein labeling methods, the proposed aptamer-mediated strategy is simple, inexpensive, and provides a highly selective, stable, and intact labeling platform that has shown great promise for future biomedical labeling and intracellular protein dynamic analyses. (paper)

Pollinator-mediated interactions in experimental arrays vary with neighbor identity.

Science.gov (United States)

Ha, Melissa K; Ivey, Christopher T

2017-02-01

Local ecological conditions influence the impact of species interactions on evolution and community structure. We investigated whether pollinator-mediated interactions between coflowering plants vary with plant density, coflowering neighbor identity, and flowering season. We conducted a field experiment in which flowering time and floral neighborhood were manipulated in a factorial design. Early- and late-flowering Clarkia unguiculata plants were placed into arrays with C. biloba neighbors, noncongeneric neighbors, additional conspecific plants, or no additional plants as a density control. We compared whole-plant pollen limitation of seed set, pollinator behavior, and pollen deposition among treatments. Interactions mediated by shared pollinators depended on the identity of the neighbor and possibly changed through time, although flowering-season comparisons were compromised by low early-season plant survival. Interactions with conspecific neighbors were likely competitive late in the season. Interactions with C. biloba appeared to involve facilitation or neutral interactions. Interactions with noncongeners were more consistently competitive. The community composition of pollinators varied among treatment combinations. Pollinator-mediated interactions involved competition and likely facilitation, depending on coflowering neighbor. Experimental manipulation helped to reveal context-dependent variation in indirect biotic interactions. © 2017 Botanical Society of America.

POLLINATOR-MEDIATED COMPETITION, REPRODUCTIVE CHARACTER DISPLACEMENT, AND THE EVOLUTION OF SELFING IN ARENARIA UNIFLORA (CARYOPHYLLACEAE).

Science.gov (United States)

Fishman, Lila; Wyatt, Robert

1999-12-01

Ecological factors that reduce the effectiveness of cross-pollination are likely to play a role in the frequent evolution of routine self-fertilization in flowering plants. However, we lack empirical evidence linking the reproductive assurance value of selfing in poor pollination environments to evolutionary shifts in mating system. Here, we investigated the adaptive significance of prior selfing in the polymorphic annual plant Arenaria uniflora (Caryophyllaceae), in which selfer populations occur only in areas of range overlap with congener A. glabra. To examine the hypothesis that secondary contact between the two species contributed to the evolution and maintenance of selfing, we used field competition experiments and controlled hand-pollinations to measure the female fitness consequences of pollinator-mediated interspecific interactions. Uniformly high fruit set by selfers in the naturally pollinated field arrays confirmed the reproductive assurance value of selfing, whereas substantial reductions in outcrosser fruit set (15%) and total seed production (20-35%) in the presence of A. glabra demonstrated that pollinator-mediated interactions can provide strong selection for self-pollination. Heterospecific pollen transfer, rather than competition for pollinator service, appears to be the primary mechanism of pollinator-mediated competition in Arenaria. Premating barriers to hybridization between outcrossers and A. glabra are extremely weak. The production of a few inviable hybrid seeds after heterospecific pollination and intermediate seed set after mixed pollinations indicates that A. glabra pollen can usurp A. uniflora ovules. Thus, any visit to A. uniflora by shared pollinators carries a potential female fitness cost. Moreover, patterns of fruit set and seed set in the competition arrays relative to controls were consistent with the receipt of mixed pollen loads, rather than a lack of pollinator visits. Competition through pollen transfer favors preemptive

The Role of Lipid Competition for Endosymbiont-Mediated Protection against Parasitoid Wasps in Drosophila

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Juan C. Paredes

2016-07-01

Full Text Available Insects commonly harbor facultative bacterial endosymbionts, such as Wolbachia and Spiroplasma species, that are vertically transmitted from mothers to their offspring. These endosymbiontic bacteria increase their propagation by manipulating host reproduction or by protecting their hosts against natural enemies. While an increasing number of studies have reported endosymbiont-mediated protection, little is known about the mechanisms underlying this protection. Here, we analyze the mechanisms underlying protection from parasitoid wasps in Drosophila melanogaster mediated by its facultative endosymbiont Spiroplasma poulsonii. Our results indicate that S. poulsonii exerts protection against two distantly related wasp species, Leptopilina boulardi and Asobara tabida. S. poulsonii-mediated protection against parasitoid wasps takes place at the pupal stage and is not associated with an increased cellular immune response. In this work, we provide three important observations that support the notion that S. poulsonii bacteria and wasp larvae compete for host lipids and that this competition underlies symbiont-mediated protection. First, lipid quantification shows that both S. poulsonii and parasitoid wasps deplete D. melanogaster hemolymph lipids. Second, the depletion of hemolymphatic lipids using the Lpp RNA interference (Lpp RNAi construct reduces wasp success in larvae that are not infected with S. poulsonii and blocks S. poulsonii growth. Third, we show that the growth of S. poulsonii bacteria is not affected by the presence of the wasps, indicating that when S. poulsonii is present, larval wasps will develop in a lipid-depleted environment. We propose that competition for host lipids may be relevant to endosymbiont-mediated protection in other systems and could explain the broad spectrum of protection provided.

The whole relationship between environmental variables and firm performance: competitive advantage and firm resources as mediator variables.

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López-Gamero, María D; Molina-Azorín, José F; Claver-Cortés, Enrique

2009-07-01

The examination of the possible direct link between environmental protection and firm performance in the literature has generally produced mixed results. The present paper contributes to the literature by using the resource-based view as a mediating process in this relationship. The study specifically tests whether or not the resource-based view of the firm mediates the positive relationships of proactive environmental management and improved environmental performance with competitive advantage, which also has consequences for financial performance. We also check the possible link between the adoption of a pioneering approach and good environmental management practices. Our findings support that early investment timing and intensity in environmental issues impact on the adoption of a proactive environmental management, which in turn helps to improve environmental performance. The findings also show that a firm's resources and competitive advantage act as mediator variables for a positive relationship between environmental protection and financial performance. This contribution is original because the present paper develops a comprehensive whole picture of this path process, which has previously only been partially discussed in the literature. In addition, this study clarifies a relevant point in the literature, namely that the effect of environmental protection on firm performance is not direct and can vary depending on the sector considered. Whereas competitive advantage in relation to costs influences financial performance in the IPPC law sector, the relevant influence in the hotel sector comes from competitive advantage through differentiation.

Mediation analysis with time varying exposures and mediators.

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VanderWeele, Tyler J; Tchetgen Tchetgen, Eric J

2017-06-01

In this paper we consider causal mediation analysis when exposures and mediators vary over time. We give non-parametric identification results, discuss parametric implementation, and also provide a weighting approach to direct and indirect effects based on combining the results of two marginal structural models. We also discuss how our results give rise to a causal interpretation of the effect estimates produced from longitudinal structural equation models. When there are time-varying confounders affected by prior exposure and mediator, natural direct and indirect effects are not identified. However, we define a randomized interventional analogue of natural direct and indirect effects that are identified in this setting. The formula that identifies these effects we refer to as the "mediational g-formula." When there is no mediation, the mediational g-formula reduces to Robins' regular g-formula for longitudinal data. When there are no time-varying confounders affected by prior exposure and mediator values, then the mediational g-formula reduces to a longitudinal version of Pearl's mediation formula. However, the mediational g-formula itself can accommodate both mediation and time-varying confounders and constitutes a general approach to mediation analysis with time-varying exposures and mediators.

The Complexity of Indirect Translation

DEFF Research Database (Denmark)

Wenjie, L. I.

2017-01-01

its complex nature, and thus determined that many facets of ITr remain to be studied. The present article will try to encompass the complexity of ITr by looking into the reasons for translating indirectly, the challenge of finding out mediating texts (MTs), indirectness in both translation...... of which have been translated and interpreted indirectly through major languages like English, will be employed as examples. Hopefully, this study will offer more insights into the nature of translation as a social activity and raise further interests in studying translation as a complex phenomenon....

Brand Experience in Banking Industry: Direct and Indirect Relationship to Loyalty

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Nuri WULANDARI

2016-02-01

Full Text Available In marketing, the meaning of value is rapidly shifting from service and relationships to experiences. It is believed that the traditional value proposition is no longer effective to compete in the market and to gain customer loyalty. By adapting the brand experience model, this study tries to validate the model in the banking industry, which is currently facing intense competition to retain customers. The brand experience construct is tested for its direct and indirect relationship toward loyalty. It is postulated that satisfaction and brand authenticity might be instrumental in mediating brand experience to loyalty. Research was conducted via in-depth interview and quantitative survey, targeting bank customers in Jakarta. The result confirmed that brand experience has direct and indirect contribution to loyalty in significant and positive manner. The research contributes in validating previous studies with a rare emphasis in banking sector. The result implies that brand experience is an important value to lead to customer loyalty in this area and subject to growing research on experience marketing.

Causal mediation analysis with multiple causally non-ordered mediators.

Science.gov (United States)

Taguri, Masataka; Featherstone, John; Cheng, Jing

2018-01-01

In many health studies, researchers are interested in estimating the treatment effects on the outcome around and through an intermediate variable. Such causal mediation analyses aim to understand the mechanisms that explain the treatment effect. Although multiple mediators are often involved in real studies, most of the literature considered mediation analyses with one mediator at a time. In this article, we consider mediation analyses when there are causally non-ordered multiple mediators. Even if the mediators do not affect each other, the sum of two indirect effects through the two mediators considered separately may diverge from the joint natural indirect effect when there are additive interactions between the effects of the two mediators on the outcome. Therefore, we derive an equation for the joint natural indirect effect based on the individual mediation effects and their interactive effect, which helps us understand how the mediation effect works through the two mediators and relative contributions of the mediators and their interaction. We also discuss an extension for three mediators. The proposed method is illustrated using data from a randomized trial on the prevention of dental caries.

Interventional Effects for Mediation Analysis with Multiple Mediators.

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Vansteelandt, Stijn; Daniel, Rhian M

2017-03-01

The mediation formula for the identification of natural (in)direct effects has facilitated mediation analyses that better respect the nature of the data, with greater consideration of the need for confounding control. The default assumptions on which it relies are strong, however. In particular, they are known to be violated when confounders of the mediator-outcome association are affected by the exposure. This complicates extensions of counterfactual-based mediation analysis to settings that involve repeatedly measured mediators, or multiple correlated mediators. VanderWeele, Vansteelandt, and Robins introduced so-called interventional (in)direct effects. These can be identified under much weaker conditions than natural (in)direct effects, but have the drawback of not adding up to the total effect. In this article, we adapt their proposal to achieve an exact decomposition of the total effect, and extend it to the multiple mediator setting. Interestingly, the proposed effects capture the path-specific effects of an exposure on an outcome that are mediated by distinct mediators, even when-as often-the structural dependence between the multiple mediators is unknown, for instance, when the direction of the causal effects between the mediators is unknown, or there may be unmeasured common causes of the mediators.

Mediation Analysis with Multiple Mediators.

Science.gov (United States)

VanderWeele, T J; Vansteelandt, S

2014-01-01

Recent advances in the causal inference literature on mediation have extended traditional approaches to direct and indirect effects to settings that allow for interactions and non-linearities. In this paper, these approaches from causal inference are further extended to settings in which multiple mediators may be of interest. Two analytic approaches, one based on regression and one based on weighting are proposed to estimate the effect mediated through multiple mediators and the effects through other pathways. The approaches proposed here accommodate exposure-mediator interactions and, to a certain extent, mediator-mediator interactions as well. The methods handle binary or continuous mediators and binary, continuous or count outcomes. When the mediators affect one another, the strategy of trying to assess direct and indirect effects one mediator at a time will in general fail; the approach given in this paper can still be used. A characterization is moreover given as to when the sum of the mediated effects for multiple mediators considered separately will be equal to the mediated effect of all of the mediators considered jointly. The approach proposed in this paper is robust to unmeasured common causes of two or more mediators.

Predatory fishes affect trophic cascades and apparent competition in temperate reefs.

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Frid, Alejandro; Marliave, Jeff

2010-08-23

We provide evidence for a trophic cascade involving apex predators and mesopredators of marine temperate reefs, lingcod and rockfish, respectively. We measured spatio-temporal variation in the relative abundance of lingcod, subadult rockfish and two shrimp groups eaten by rockfish (Pandalus sp. and three smaller-bodied genera aggregated). Lingcod had an indirect positive effect on shrimps, as mediated by the direct negative effects of lingcod on rockfish and of rockfish on shrimps. These top-down effects on shrimps, however, were stronger for Pandalus than for small-bodied shrimps. Further, abundances of Pandalus and small-bodied shrimps were negatively correlated and the latter had a stronger positive effect on rockfish, suggesting that rockfish mediated asymmetrical apparent competition between shrimps. Our results indicate mechanisms by which predatory fishes may influence the structure of marine communities.

Shattered illusions: the effect of explicit memory mediation on an indirect memory test.

Science.gov (United States)

Gooding, P A; Mayes, A R; Meudell, P R

1999-05-01

Four experiments were conducted to explore the possible involvement of explicit memory in an indirect memory test in which white noise accompanying old sentences was judged to be quieter than white noise accompanying new sentences (Jacoby, Allan, Collins & Larwill, 1988). Experiment 1 established that this effect lasted up to 1 week. Experiment 2 found that a group of amnesic patients showed a noise effect that was marginally above chance and not significantly less that that of their matched controls after a delay of one day. Effect of time pressure at test (Experiment 3) and divided attention at study (Experiment 4) suggested that the memory processes mediating the noise effect were not automatic, although the possibility that the processes involve enhanced fluency is also discussed.

Education and health and well-being: direct and indirect effects with multiple mediators and interactions with multiple imputed data in Stata.

Science.gov (United States)

Sheikh, Mashhood Ahmed; Abelsen, Birgit; Olsen, Jan Abel

2017-11-01

Previous methods for assessing mediation assume no multiplicative interactions. The inverse odds weighting (IOW) approach has been presented as a method that can be used even when interactions exist. The substantive aim of this study was to assess the indirect effect of education on health and well-being via four indicators of adult socioeconomic status (SES): income, management position, occupational hierarchy position and subjective social status. 8516 men and women from the Tromsø Study (Norway) were followed for 17 years. Education was measured at age 25-74 years, while SES and health and well-being were measured at age 42-91 years. Natural direct and indirect effects (NIE) were estimated using weighted Poisson regression models with IOW. Stata code is provided that makes it easy to assess mediation in any multiple imputed dataset with multiple mediators and interactions. Low education was associated with lower SES. Consequently, low SES was associated with being unhealthy and having a low level of well-being. The effect (NIE) of education on health and well-being is mediated by income, management position, occupational hierarchy position and subjective social status. This study contributes to the literature on mediation analysis, as well as the literature on the importance of education for health-related quality of life and subjective well-being. The influence of education on health and well-being had different pathways in this Norwegian sample. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Competition and Consumer Behavior in the Context of the Digital Economy

Directory of Open Access Journals (Sweden)

Elena-Mădălina Vătămănescu

2017-05-01

Full Text Available The current paper aims to investigate the relation between competition and online purchasing decision-making, integrating consumer protection awareness and the corresponding consumer behavior as mediators. The focus is on both subjective and objective measures related to the level of consumer awareness and action in a fast-growing competition, potentiated by the digital economy. In order to investigate the relations between the aforementioned concepts, a questionnaire-based survey was conducted, using a sample of 257 students from three top Romanian universities. Based upon the theoretical directions presented in the literature review, a conceptual model was elaborated and tested by employing a partial least squares structural equation modeling technique. As the examination of the structural model indicated, online purchasing decision-making is indirectly influenced by the high competition in the digital economy, by means of consumer protection awareness and consumer protection behavior. At this level, the analyzed factors, namely the competition in the digital economy, the consumer protection awareness and the consumer behavior with respect to the consumer protection policies, explain over 16% in the variance of the online purchasing decision-making.

Adaptive evolution of body size subject to indirect effect in trophic cascade system.

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Wang, Xin; Fan, Meng; Hao, Lina

2017-09-01

Trophic cascades represent a classic example of indirect effect and are wide-spread in nature. Their ecological impact are well established, but the evolutionary consequences have received even less theoretical attention. We theoretically and numerically investigate the trait (i.e., body size of consumer) evolution in response to indirect effect in a trophic cascade system. By applying the quantitative trait evolutionary theory and the adaptive dynamic theory, we formulate and explore two different types of eco-evolutionary resource-consumer-predator trophic cascade model. First, an eco-evolutionary model incorporating the rapid evolution is formulated to investigate the effect of rapid evolution of the consumer's body size, and to explore the impact of density-mediate indirect effect on the population dynamics and trait dynamics. Next, by employing the adaptive dynamic theory, a long-term evolutionary model of consumer body size is formulated to evaluate the effect of long-term evolution on the population dynamics and the effect of trait-mediate indirect effect. Those models admit rich dynamics that has not been observed yet in empirical studies. It is found that, both in the trait-mediated and density-mediated system, the body size of consumer in predator-consumer-resource interaction (indirect effect) evolves smaller than that in consumer-resource and predator-consumer interaction (direct effect). Moreover, in the density-mediated system, we found that the evolution of consumer body size contributes to avoiding consumer extinction (i.e., evolutionary rescue). The trait-mediate and density-mediate effects may produce opposite evolutionary response. This study suggests that the trophic cascade indirect effect affects consumer evolution, highlights a more comprehensive mechanistic understanding of the intricate interplay between ecological and evolutionary force. The modeling approaches provide avenue for study on indirect effects from an evolutionary perspective

OH radicals from the indirect actions of X-rays induce cell lethality and mediate the majority of the oxygen enhancement effect.

Science.gov (United States)

Hirayama, Ryoichi; Ito, Atsushi; Noguchi, Miho; Matsumoto, Yoshitaka; Uzawa, Akiko; Kobashi, Gen; Okayasu, Ryuichi; Furusawa, Yoshiya

2013-11-01

We examined OH radical-mediated indirect actions from X irradiation on cell killing in wild-type Chinese hamster ovary cell lines (CHO and AA8) under oxic and hypoxic conditions, and compared the contribution of direct and indirect actions under both conditions. The contribution of indirect action on cell killing can be estimated from the maximum degree of protection by dimethylsulfoxide, which suppresses indirect action by quenching OH radicals without affecting the direct action of X rays on cell killing. The contributions of indirect action on cell killing of CHO cells were 76% and 50% under oxic and hypoxic conditions, respectively, and those for AA8 cells were 85% and 47%, respectively. Therefore, the indirect action on cell killing was enhanced by oxygen during X irradiation in both cell lines tested. Oxygen enhancement ratios (OERs) at the 10% survival level (D10 or LD90) for CHO and AA8 cells were 2.68 ± 0.15 and 2.76 ± 0.08, respectively. OERs were evaluated separately for indirect and direct actions, which gave the values of 3.75 and 2.01 for CHO, and 4.11 and 1.32 for AA8 cells, respectively. Thus the generally accepted OER value of ∼3 is best understood as the average of the OER values for both indirect and direct actions. These results imply that both indirect and direct actions on cell killing require oxygen for the majority of lethal DNA damage, however, oxygen plays a larger role in indirect than for direct effects. Conversely, the lethal damage induced by the direct action of X rays are less affected by oxygen concentration.

Water-use efficiency and relative growth rate mediate competitive interactions in Sonoran Desert winter annual plants.

Science.gov (United States)

Gremer, Jennifer R; Kimball, Sarah; Keck, Katie R; Huxman, Travis E; Angert, Amy L; Venable, D Lawrence

2013-10-01

A functional approach to investigating competitive interactions can provide a mechanistic understanding of processes driving population dynamics, community assembly, and the maintenance of biodiversity. In Sonoran Desert annual plants, a trade-off between relative growth rate (RGR) and water-use efficiency (WUE) contributes to species differences in population dynamics that promote long-term coexistence. Traits underlying this trade-off explain variation in demographic responses to precipitation as well as life history and phenological patterns. Here, we ask how these traits mediate competitive interactions. • We conducted competition trials for three species occupying different positions along the RGR-WUE trade-off axis and compared the effects of competition at high and low soil moisture. We compared competitive effect (ability to suppress neighbors) and competitive response (ability to withstand competition from neighbors) among species. • The RGR-WUE trade-off predicted shifts in competitive responses at different soil moistures. The high-RGR species was more resistant to competition in high water conditions, while the opposite was true for the high-WUE species. The intermediate RGR species tended to have the strongest impact on all neighbors, so competitive effects did not scale directly with differences in RGR and WUE among competitors. • Our results reveal mechanisms underlying long-term variation in fitness: high-RGR species perform better in years with large, frequent rain events and can better withstand competition under wetter conditions. The opposite is true for high-WUE species. Such resource-dependent responses strongly influence community dynamics and can promote coexistence in variable environments.

Neural evidence for competition-mediated suppression in the perception of a single object.

Science.gov (United States)

Cacciamani, Laura; Scalf, Paige E; Peterson, Mary A

2015-11-01

Multiple objects compete for representation in visual cortex. Competition may also underlie the perception of a single object. Computational models implement object perception as competition between units on opposite sides of a border. The border is assigned to the winning side, which is perceived as an object (or "figure"), whereas the other side is perceived as a shapeless ground. Behavioral experiments suggest that the ground is inhibited to a degree that depends on the extent to which it competed for object status, and that this inhibition is relayed to low-level brain areas. Here, we used fMRI to assess activation for ground regions of task-irrelevant novel silhouettes presented in the left or right visual field (LVF or RVF) while participants performed a difficult task at fixation. Silhouettes were designed so that the insides would win the competition for object status. The outsides (grounds) suggested portions of familiar objects in half of the silhouettes and novel objects in the other half. Because matches to object memories affect the competition, these two types of silhouettes operationalized, respectively, high competition and low competition from the grounds. The results showed that activation corresponding to ground regions was reduced for high- versus low-competition silhouettes in V4, where receptive fields (RFs) are large enough to encompass the familiar objects in the grounds, and in V1/V2, where RFs are much smaller. These results support a theory of object perception involving competition-mediated ground suppression and feedback from higher to lower levels. This pattern of results was observed in the left hemisphere (RVF), but not in the right hemisphere (LVF). One explanation of the lateralized findings is that task-irrelevant silhouettes in the RVF captured attention, allowing us to observe these effects, whereas those in the LVF did not. Experiment 2 provided preliminary behavioral evidence consistent with this possibility. Copyright �

The indirect association of job strain with long-term sickness absence through bullying: a mediation analysis using structural equation modeling.

Science.gov (United States)

Janssens, Heidi; Braeckman, Lutgart; De Clercq, Bart; Casini, Annalisa; De Bacquer, Dirk; Kittel, France; Clays, Els

2016-08-22

In this longitudinal study the complex interplay between both job strain and bullying in relation to sickness absence was investigated. Following the "work environment hypothesis", which establishes several work characteristics as antecedents of bullying, we assumed that job strain, conceptualized by the Job-Demand-Control model, has an indirect relation with long-term sickness absence through bullying. The sample consisted of 2983 Belgian workers, aged 30 to 55 years, who participated in the Belstress III study. They completed a survey, including the Job Content Questionnaire and a bullying inventory, at baseline. Their sickness absence figures were registered during 1 year follow-up. Long-term sickness absence was defined as at least 15 consecutive days. A mediation analysis, using structural equation modeling, was performed to examine the indirect association of job strain through bullying with long-term sickness absence. The full structural model was adjusted for several possible confounders: age, gender, occupational group, educational level, company, smoking habits, alcohol use, body mass index, self-rated health, baseline long-term sickness absence and neuroticism. The results support the hypothesis: a significant indirect association of job strain with long-term sickness absence through bullying was observed, suggesting that bullying is an intermediate variable between job strain and long-term sickness absence. No evidence for the reversed pathway of an indirect association of bullying through job strain was found. Bullying was observed as a mediating variable in the relation between job strain and sickness absence. The results suggest that exposure to job strain may create circumstances in which a worker risks to become a target of bullying. Our findings are generally in line with the work environment hypothesis, which emphasizes the importance of organizational work factors in the origin of bullying. This study highlights that remodeling jobs to reduce

Serological response to an indirect and a competitive elisa in heifers vaccinated with Brucella abortus strain 19

International Nuclear Information System (INIS)

Carrasco, E.A.; Uzal, F.A.; Echaide, S.

1998-01-01

The different serologic techniques for bovine brucellosis diagnosis have different abilities to detect antibodies after vaccination with Brucella abortus strain 19. The humoral response in heifers vaccinated with Brucella abortus strain 19 was evaluated by using several serologic techniques. In the experimental field of INTA, Pilcaniyeu, Rio Negro province, sixteen 5 months old heifers were vaccinated subcutaneously with a standard dose (2ml, containing 20x10 9 to 10x10 9 living organisms) of Brucella abortus strain 19. Sera from all the heifers were obtained on 18 occasions (one 87 days before vaccination, one immediately before vaccination and on 16 occasions after vaccination, during 488 days) and analyzed by buffered plate antigen test, rose bengal test, standard tube agglutination test, 2-mercaptoetanol test, complement fixation test, indirect ELISA, and competitive ELISA. Prior vaccination, 100% of the heifers gave negative results in all the techniques used, while 100% of them gave positive reaction in the first sampling after vaccination to all the techniques, with the exception of standard tube agglutination test that showed agglutinating titters of 1/100 or higher (positive threshold) in only 71.4% of the heifers. The indirect ELISA technique showed a reducing percentage of positive animals up until 316 days after vaccination, after which positive results were obtained. The competitive ELISA gave positive results in a variable number of heifers up to 253 days after vaccination when 100% of the sera were negative to this technique. Buffered plate antigen test was the technique that gave positive results for a longest period, being 100% of the animals negative to this technique at 450 days after vaccination. The other serological techniques assayed gave positive results during variable periods of time, intermediate between standard tube agglutination test and buffered plate antigen test. Although the present results were obtained from a limited number of

The effect of green supply chain management implementation to marketing performance through company competitiveness (study on paper industry in West Java)

Science.gov (United States)

Hijuzaman, O.; Rahayu, A.; Kusnendi

2018-05-01

The purpose of this study was to determine and analyze the effect of direct and indirect implementation of Green Supply-Chain Management (GSCM) on the Performance Marketing and Competitiveness Mediation Paper Company in West Java province. Object This research is the paper company that existed in West Java Province, which amounts to 30 companies as well as a sample of research, while variables studied are Variable Green Supply- Chain Management, Company Competitiveness Variable and Variable of Paper Marketing Industry Performance in West Java Province. The method used SEM with Variance Based or Component Based with Software used is SmartPLS 3.0. On this research are identified that no effect of Competitiveness on Marketing Performance in Paper Companies in West Java Province.

Detection of Candida albicans Sap2 in cancer patient serum samples by an indirect competitive enzyme-linked immunosorbent assay for the diagnosis of candidiasis.

Science.gov (United States)

Wang, Yicun; Gao, Xiang; Zhi Gang, J U; Liu, Jingyuan; Dong, Shuai; Wang, Li

2013-01-01

The secreted aspartyl proteinases 2 (Sap2) of Candida albicans (C. albicans) is a potential marker of candididasis. It is a virulence factor associated with adherence and tissue invasion. In order to detect Sap2 in clinical sera, we developed an indirect competitive enzyme-linked immunosorbent assay (ELISA). Polyclonal antibodies were produced for Sap2 by injecting Sap2 into a New Zealand White inbred rabbit. They could be used at a dilution exceeding 1:1200 in an indirect ELISA, and detected Sap2 concentration up to 1 ng/mL. Of the 286 cancer serum samples tested, 16.8% were found as candidiasis. The test was simple and economical to perform and had a level of sensitivity for detection of low-titer positive sera; thus, it may be proven to be of value in epidemiological studies on candidiasis.

Detection of Candida albicans Sap2 in cancer patient serum samples by an indirect competitive enzyme-linked immunosorbent assay for the diagnosis of candidiasis

OpenAIRE

Yicun Wang; Xiang Gao; J U Zhi gang; Jingyuan Liu; Shuai Dong; Li Wang

2013-01-01

Background: The secreted aspartyl proteinases 2 (Sap2) of Candida albicans (C. albicans) is a potential marker of candididasis. It is a virulence factor associated with adherence and tissue invasion. Aim: In order to detect Sap2 in clinical sera, we developed an indirect competitive enzyme-linked immunosorbent assay (ELISA). Materials and Methods: Polyclonal antibodies were produced for Sap2 by injecting Sap2 into a New Zealand White inbred rabbit. They could be used at a dilution exceeding 1...

Socially cued seminal fluid gene expression mediates responses in ejaculate quality to sperm competition risk.

Science.gov (United States)

Simmons, Leigh W; Lovegrove, Maxine

2017-08-30

There is considerable evidence that males will increase the number of sperm ejaculated in response to sperm competition risk. However, whether they have the capacity to adjust seminal fluid components of the ejaculate has received less attention. Male crickets ( Teleogryllus oceanicus ) have been shown to adjust the viability of sperm in their ejaculate in response to sperm competition risk. Here we show that socially mediated plasticity in sperm viability is probably due, at least in part, to male adjustments in the protein composition of the seminal fluid. Seven seminal fluid protein genes were found to have an increased expression in males exposed to rival calls. Increased expression of these genes was correlated with increased sperm viability in whole ejaculates, and gene knockdown confirmed that at least one of these proteins promotes sperm viability. Our results lend support for recent theoretical models that predict complex responses in male allocation to seminal fluid composition in response to sperm competition risk. © 2017 The Author(s).

[Importance of perceived competition and motivation to the mental health of college athletes].

Science.gov (United States)

Castillo, Isabel; Molina-García, Javier; Alvarez, Octavio

2010-01-01

This research analyzes the direct and indirect relationships among self-motivation, perceived competition and psychological well-being and ill-being. Data from 491 Spanish college students (299 men and 192 women) who practice sports were collected using a cross-sectional design. Statistical analyses were carried out using structural equation modeling. Psychological well-being was directly fostered by perceived competition and indirectly by self- motivation. Furthermore, perceived competition was negatively associated with psychological ill-being. Perceived competition and self-motivation are important to the psychological well-being of college students and to avoiding ill-being.

Detection of Candida albicans Sap2 in cancer patient serum samples by an indirect competitive enzyme-linked immunosorbent assay for the diagnosis of candidiasis

Directory of Open Access Journals (Sweden)

Yicun Wang

2013-01-01

Full Text Available Background: The secreted aspartyl proteinases 2 (Sap2 of Candida albicans (C. albicans is a potential marker of candididasis. It is a virulence factor associated with adherence and tissue invasion. Aim: In order to detect Sap2 in clinical sera, we developed an indirect competitive enzyme-linked immunosorbent assay (ELISA. Materials and Methods: Polyclonal antibodies were produced for Sap2 by injecting Sap2 into a New Zealand White inbred rabbit. They could be used at a dilution exceeding 1:1200 in an indirect ELISA, and detected Sap2 concentration up to 1 ng/mL. Results: Of the 286 cancer serum samples tested, 16.8% were found as candidiasis. The test was simple and economical to perform and had a level of sensitivity for detection of low-titer positive sera; thus, it may be proven to be of value in epidemiological studies on candidiasis.

The power of indirect social ties

OpenAIRE

Zuo, Xiang; Blackburn, Jeremy; Kourtellis, Nicolas; Skvoretz, John; Iamnitchi, Adriana

2014-01-01

While direct social ties have been intensely studied in the context of computer-mediated social networks, indirect ties (e.g., friends of friends) have seen little attention. Yet in real life, we often rely on friends of our friends for recommendations (of good doctors, good schools, or good babysitters), for introduction to a new job opportunity, and for many other occasional needs. In this work we attempt to 1) quantify the strength of indirect social ties, 2) validate it, and 3) empiricall...

Pesticide-mediated interspecific competition between local and invasive thrips pests

Science.gov (United States)

Zhao, Xueyin; Reitz, Stuart R.; Yuan, Huiguo; Lei, Zhongren; Paini, Dean Ronald; Gao, Yulin

2017-01-01

Competitive interactions between species can be mitigated or even reversed in the presence of anthropogenic influences. The thrips species Frankliniella occidentalis and Thrips tabaci are highly invasive and damaging agricultural pests throughout the world. Where the species co-occur, one species tends to eventually predominate over the other. Avermectin and beta-cypermethrin are commonly used insecticides to manage thrips in China, and laboratory bioassays demonstrated that F. occidentalis is significantly less susceptible than T. tabaci to these insecticides. In laboratory cage trials in which both species were exposed to insecticide treated cabbage plants, F. occidentalis became the predominant species. In contrast, T. tabaci completely displaced F. occidentalis on plants that were not treated with insecticides. In field trials, the species co-existed on cabbage before insecticide treatments began, but with T. tabaci being the predominant species. Following application of avermectin or beta-cypermethrin, F. occidentalis became the predominant species, while in plots not treated with insecticides, T. tabaci remained the predominant species. These results indicate that T. tabaci is an intrinsically superior competitor to F. occidentalis, but its competitive advantage can be counteracted through differential susceptibilities of the species to insecticides. These results further demonstrate the importance of external factors, such as insecticide applications, in mediating the outcome of interspecific interactions and produce rapid unanticipated shifts in the demographics of pest complexes. PMID:28084404

Pesticide-mediated interspecific competition between local and invasive thrips pests.

Science.gov (United States)

Zhao, Xueyin; Reitz, Stuart R; Yuan, Huiguo; Lei, Zhongren; Paini, Dean Ronald; Gao, Yulin

2017-01-13

Competitive interactions between species can be mitigated or even reversed in the presence of anthropogenic influences. The thrips species Frankliniella occidentalis and Thrips tabaci are highly invasive and damaging agricultural pests throughout the world. Where the species co-occur, one species tends to eventually predominate over the other. Avermectin and beta-cypermethrin are commonly used insecticides to manage thrips in China, and laboratory bioassays demonstrated that F. occidentalis is significantly less susceptible than T. tabaci to these insecticides. In laboratory cage trials in which both species were exposed to insecticide treated cabbage plants, F. occidentalis became the predominant species. In contrast, T. tabaci completely displaced F. occidentalis on plants that were not treated with insecticides. In field trials, the species co-existed on cabbage before insecticide treatments began, but with T. tabaci being the predominant species. Following application of avermectin or beta-cypermethrin, F. occidentalis became the predominant species, while in plots not treated with insecticides, T. tabaci remained the predominant species. These results indicate that T. tabaci is an intrinsically superior competitor to F. occidentalis, but its competitive advantage can be counteracted through differential susceptibilities of the species to insecticides. These results further demonstrate the importance of external factors, such as insecticide applications, in mediating the outcome of interspecific interactions and produce rapid unanticipated shifts in the demographics of pest complexes.

Mediation Analysis with Multiple Mediators

OpenAIRE

VanderWeele, T.J.; Vansteelandt, S.

2014-01-01

Recent advances in the causal inference literature on mediation have extended traditional approaches to direct and indirect effects to settings that allow for interactions and non-linearities. In this paper, these approaches from causal inference are further extended to settings in which multiple mediators may be of interest. Two analytic approaches, one based on regression and one based on weighting are proposed to estimate the effect mediated through multiple mediators and the effects throu...

The indirect association of job strain with long-term sickness absence through bullying: a mediation analysis using structural equation modeling

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Heidi Janssens

2016-08-01

Full Text Available Abstract Background In this longitudinal study the complex interplay between both job strain and bullying in relation to sickness absence was investigated. Following the “work environment hypothesis”, which establishes several work characteristics as antecedents of bullying, we assumed that job strain, conceptualized by the Job-Demand-Control model, has an indirect relation with long-term sickness absence through bullying. Methods The sample consisted of 2983 Belgian workers, aged 30 to 55 years, who participated in the Belstress III study. They completed a survey, including the Job Content Questionnaire and a bullying inventory, at baseline. Their sickness absence figures were registered during 1 year follow-up. Long-term sickness absence was defined as at least 15 consecutive days. A mediation analysis, using structural equation modeling, was performed to examine the indirect association of job strain through bullying with long-term sickness absence. The full structural model was adjusted for several possible confounders: age, gender, occupational group, educational level, company, smoking habits, alcohol use, body mass index, self-rated health, baseline long-term sickness absence and neuroticism. Results The results support the hypothesis: a significant indirect association of job strain with long-term sickness absence through bullying was observed, suggesting that bullying is an intermediate variable between job strain and long-term sickness absence. No evidence for the reversed pathway of an indirect association of bullying through job strain was found. Conclusions Bullying was observed as a mediating variable in the relation between job strain and sickness absence. The results suggest that exposure to job strain may create circumstances in which a worker risks to become a target of bullying. Our findings are generally in line with the work environment hypothesis, which emphasizes the importance of organizational work factors in the

Three principles of competitive nonlinear pricing

OpenAIRE

Page Junior, Frank H.; Monteiro, P. K.

2002-01-01

We make three contributions to the theory of contracting under asymmetric information. First , we establish a competitive analog to the revelation principle which we call the implementation principle. This principle provides a complete characterization of all incentive compatible, indirect contracting mechanisms in terms of contract catalogs (or menus), and allows us to conclude that in competitive contracting situations, firms in choosing their contracting strategies can restrict attention, ...

Competition, Ownership and Productivity

DEFF Research Database (Denmark)

Baghdasaryan, Delia; la Cour, Lisbeth

2013-01-01

Theoretical results support two concurrent views regarding the mediating role that ownership structure might play on the effect of competition on firm performance. According to one stream of literature, competition has a high, positive impact in companies that have an effective ownership structur...

Substrate-mediated delivery of gene complex nanoparticles via polydopamine coating for enhancing competitiveness of endothelial cells.

Science.gov (United States)

Li, Bo-Chao; Chang, Hao; Ren, Ke-Feng; Ji, Jian

2016-11-01

Substrate-mediated delivery of functional plasmid DNA (pDNA) has been proven to be a promising strategy to promote competitiveness of endothelial cells (ECs) over smooth muscle cells (SMCs), which is beneficial to inducing fast endothelialization of implanted vascular devices. Thus, it is of great importance to develop universal approaches with simplicity and easiness to immobilize DNA complex nanoparticles on substrates. In this study, the bioinspired polydopamine (PDA) coating was employed in immobilization of DNA complex nanoparticles, which were composed of protamine (PrS) and plasmid DNA encoding with hepatocyte growth factor (HGF-pDNA) gene. We demonstrated that the DNA complex nanoparticles can be successfully immobilized onto the PDA surface. Consequently, the HGF expression of both ECs and SMCs were significantly improved when they cultured on the DNA complex nanoparticles-immobilized substrates. Furthermore, EC proliferation was specifically promoted due to bioactivity of HGF, leading to an enhancement of EC competitiveness over SMCs. Our findings demonstrated the substrate-mediated functional gene nanoparticle delivery through PDA coating as a simple and efficient approach. It may hold great potential in the field of interventional cardiovascular implants. Copyright © 2016 Elsevier B.V. All rights reserved.

Indirect competitive immunoassay for the detection of fungicide Thiabendazole in whole orange samples by Surface Plasmon Resonance.

Science.gov (United States)

Estevez, M-Carmen; Belenguer, Jose; Gomez-Montes, Silvia; Miralles, Javier; Escuela, Alfonso M; Montoya, Angel; Lechuga, Laura M

2012-12-07

A highly sensitive and specific SPR-based competitive immunoassay for the detection of Thiabendazole (TBZ) has been developed. An indirect format where a TBZ-protein conjugate is immobilized onto gold surfaces has been selected. Under the optimal conditions, a LOD of 0.67 nM (0.13 μg L(-1)) and an IC(50) of 3.2 nM (0.64 μg L(-1)) have been achieved which are comparable to the values obtained by conventional ELISA. Analysis of real samples has been attempted by first evaluating the influence of complex matrix samples coming from whole oranges and secondly measuring samples containing TBZ previously evaluated by chromatographic methods. A methanolic extraction procedure followed by a simple dilution in assay buffer has proven to be sufficient to measure orange samples using the developed immunoassay with an excellent recovery percentage. The sensitivity and the feasibility of measuring whole orange samples demonstrate the effectiveness and robustness of the SPR biosensor, which can be useful for the determination of TBZ in food at concentrations below the Maximum Residue Levels (MRLs) established by the European legislation.

Apparent competition and native consumers exacerbate the strong competitive effect of an exotic plant species.

Science.gov (United States)

Orrock, John L; Dutra, Humberto P; Marquis, Robert J; Barber, Nicholas

2015-04-01

Direct and indirect effects can play a key role in invasions, but experiments evaluating both are rare. We examined the roles of direct competition and apparent competition by exotic Amur honeysuckle (Lonicera maackii) by manipulating (1) L. maackii vegetation, (2) presence of L. maackii fruits, and (3) access to plants by small mammals and deer. Direct competition with L. maackii reduced the abundance and richness of native and exotic species, and native consumers significantly reduced the abundance and richness of native species. Although effects of direct competition and consumption were more pervasive, richness of native plants was also reduced through apparent competition, as small-mammal consumers reduced richness only when L. maackii fruits were present. Our experiment reveals the multiple, interactive pathways that affect the success and impact of an invasive exotic plant: exotic plants may directly benefit from reduced attack by native consumers, may directly exert strong competitive effects on native plants, and may also benefit from apparent competition.

Competitive outcome of Daphnia-Simocephalus experimental microcosms: salinity versus priority effects.

Directory of Open Access Journals (Sweden)

Cláudia Loureiro

Full Text Available Competition is a major driving force in freshwaters, especially given the cyclic nature and dynamics of pelagic food webs. Competition is especially important in the initial species assortment during colonization and re-colonization events, which depends strongly on the environmental context. Subtle changes, such as saline intrusion, may disrupt competitive relationships and, thus, influence community composition. Bearing this in mind, our objective was to assess whether low salinity levels (using NaCl as a proxy alter the competitive outcome (measured as the rate of population biomass increase of Daphnia-Simocephalus experimental microcosms, taking into account interactions with priority effects (sequential species arrival order. With this approach, we aimed to experimentally demonstrate a putative mechanism of differential species sorting in brackish environments or in freshwaters facing secondary salinization. Experiments considered three salinity levels, regarding NaCl added (0.00, 0.75 and 1.50 g L(-1, crossed with three competition scenarios (no priority, priority of Daphnia over Simocephalus, and vice-versa. At lower NaCl concentrations (0.00 and 0.75 g L(-1, Daphnia was a significantly superior competitor, irrespective of the species inoculation order, suggesting negligible priority effects. However, the strong decrease in Daphnia population growth at 1.50 g L(-1 alleviated the competitive pressure on Simocephalus, causing an inversion of the competitive outcome in favour of Simocephalus. The intensity of this inversion depended on the competition scenario. This salinity-mediated disruption of the competitive outcome demonstrates that subtle environmental changes produce indirect effects in key ecological mechanisms, thus altering community composition, which may lead to serious implications in terms of ecosystem functioning (e.g. lake regime shifts due to reduced grazing and biodiversity.

Direct and indirect effects of climate change on a prairie plant community.

Directory of Open Access Journals (Sweden)

Peter B Adler

2009-09-01

Full Text Available Climate change directly affects species by altering their physical environment and indirectly affects species by altering interspecific interactions such as predation and competition. Recent studies have shown that the indirect effects of climate change may amplify or counteract the direct effects. However, little is known about the the relative strength of direct and indirect effects or their potential to impact population persistence.We studied the effects of altered precipitation and interspecific interactions on the low-density tiller growth rates and biomass production of three perennial grass species in a Kansas, USA mixed prairie. We transplanted plugs of each species into local neighborhoods of heterospecific competitors and then exposed the plugs to a factorial manipulation of growing season precipitation and neighbor removal. Precipitation treatments had significant direct effects on two of the three species. Interspecific competition also had strong effects, reducing low-density tiller growth rates and aboveground biomass production for all three species. In fact, in the presence of competitors, (log tiller growth rates were close to or below zero for all three species. However, we found no convincing evidence that per capita competitive effects changed with precipitation, as shown by a lack of significant precipitation x competition interactions.We found little evidence that altered precipitation will influence per capita competitive effects. However, based on species' very low growth rates in the presence of competitors in some precipitation treatments, interspecific interactions appear strong enough to affect the balance between population persistence and local extinction. Therefore, ecological forecasting models should include the effect of interspecific interactions on population growth, even if such interaction coefficients are treated as constants.

Expression of future prospective in indirect speech

Directory of Open Access Journals (Sweden)

Bodnaruk Elena Vladimirovna

2015-03-01

Full Text Available The article analyzes the characteristics and use of grammatical semantics and lexical and grammatical means used to create future prospects in double indirect discourse. The material for the study were epic works by contemporary German writers. In the analysis of the empirical material it has been pointed out that indirect discourse has preterial basis and is the kind of most frequent inner speech of characters. The most widely used form with future semantics in preterial indirect speech is conditional I, formally having a conjunctive basis, but is mostly used with the indicative semantics. Competitive to conditional I in indirect speech is preterial indicative. A characteristic feature of the indirect speech is the use of modal verbs, which, thanks to its semantics is usually referred as an action at a later term, creating the prospect of future statements. The most frequent were modal verbs wollen and sollen in the form of the preterite, more rare verbs were m ssen and k nnen. German indirect speech distinguishes the ability to use forms on the basis of conjunctive: preterite and plusquamperfect of conjunctive. Both forms express values similar to those of the indicative. However, conjunctive forms the basis of the data shown in a slightly more pronounced seme of uncertainty that accompanies future uses of these forms in indirect speech. In addition, plusquamperfect conjunctive differs from others by the presence of the seme of completeness.

Sensitivity analysis for unobserved confounding of direct and indirect effects using uncertainty intervals.

Science.gov (United States)

Lindmark, Anita; de Luna, Xavier; Eriksson, Marie

2018-05-10

To estimate direct and indirect effects of an exposure on an outcome from observed data, strong assumptions about unconfoundedness are required. Since these assumptions cannot be tested using the observed data, a mediation analysis should always be accompanied by a sensitivity analysis of the resulting estimates. In this article, we propose a sensitivity analysis method for parametric estimation of direct and indirect effects when the exposure, mediator, and outcome are all binary. The sensitivity parameters consist of the correlations between the error terms of the exposure, mediator, and outcome models. These correlations are incorporated into the estimation of the model parameters and identification sets are then obtained for the direct and indirect effects for a range of plausible correlation values. We take the sampling variability into account through the construction of uncertainty intervals. The proposed method is able to assess sensitivity to both mediator-outcome confounding and confounding involving the exposure. To illustrate the method, we apply it to a mediation study based on the data from the Swedish Stroke Register (Riksstroke). An R package that implements the proposed method is available. Copyright © 2018 John Wiley & Sons, Ltd.

Ratio-of-Mediator-Probability Weighting for Causal Mediation Analysis in the Presence of Treatment-by-Mediator Interaction

Science.gov (United States)

Hong, Guanglei; Deutsch, Jonah; Hill, Heather D.

2015-01-01

Conventional methods for mediation analysis generate biased results when the mediator--outcome relationship depends on the treatment condition. This article shows how the ratio-of-mediator-probability weighting (RMPW) method can be used to decompose total effects into natural direct and indirect effects in the presence of treatment-by-mediator…

Method for evaluating multiple mediators: mediating effects of smoking and COPD on the association between the CHRNA5-A3 variant and lung cancer risk.

Science.gov (United States)

Wang, Jian; Spitz, Margaret R; Amos, Christopher I; Wu, Xifeng; Wetter, David W; Cinciripini, Paul M; Shete, Sanjay

2012-01-01

A mediation model explores the direct and indirect effects between an independent variable and a dependent variable by including other variables (or mediators). Mediation analysis has recently been used to dissect the direct and indirect effects of genetic variants on complex diseases using case-control studies. However, bias could arise in the estimations of the genetic variant-mediator association because the presence or absence of the mediator in the study samples is not sampled following the principles of case-control study design. In this case, the mediation analysis using data from case-control studies might lead to biased estimates of coefficients and indirect effects. In this article, we investigated a multiple-mediation model involving a three-path mediating effect through two mediators using case-control study data. We propose an approach to correct bias in coefficients and provide accurate estimates of the specific indirect effects. Our approach can also be used when the original case-control study is frequency matched on one of the mediators. We employed bootstrapping to assess the significance of indirect effects. We conducted simulation studies to investigate the performance of the proposed approach, and showed that it provides more accurate estimates of the indirect effects as well as the percent mediated than standard regressions. We then applied this approach to study the mediating effects of both smoking and chronic obstructive pulmonary disease (COPD) on the association between the CHRNA5-A3 gene locus and lung cancer risk using data from a lung cancer case-control study. The results showed that the genetic variant influences lung cancer risk indirectly through all three different pathways. The percent of genetic association mediated was 18.3% through smoking alone, 30.2% through COPD alone, and 20.6% through the path including both smoking and COPD, and the total genetic variant-lung cancer association explained by the two mediators was 69.1%.

Method for evaluating multiple mediators: mediating effects of smoking and COPD on the association between the CHRNA5-A3 variant and lung cancer risk.

Directory of Open Access Journals (Sweden)

Jian Wang

Full Text Available A mediation model explores the direct and indirect effects between an independent variable and a dependent variable by including other variables (or mediators. Mediation analysis has recently been used to dissect the direct and indirect effects of genetic variants on complex diseases using case-control studies. However, bias could arise in the estimations of the genetic variant-mediator association because the presence or absence of the mediator in the study samples is not sampled following the principles of case-control study design. In this case, the mediation analysis using data from case-control studies might lead to biased estimates of coefficients and indirect effects. In this article, we investigated a multiple-mediation model involving a three-path mediating effect through two mediators using case-control study data. We propose an approach to correct bias in coefficients and provide accurate estimates of the specific indirect effects. Our approach can also be used when the original case-control study is frequency matched on one of the mediators. We employed bootstrapping to assess the significance of indirect effects. We conducted simulation studies to investigate the performance of the proposed approach, and showed that it provides more accurate estimates of the indirect effects as well as the percent mediated than standard regressions. We then applied this approach to study the mediating effects of both smoking and chronic obstructive pulmonary disease (COPD on the association between the CHRNA5-A3 gene locus and lung cancer risk using data from a lung cancer case-control study. The results showed that the genetic variant influences lung cancer risk indirectly through all three different pathways. The percent of genetic association mediated was 18.3% through smoking alone, 30.2% through COPD alone, and 20.6% through the path including both smoking and COPD, and the total genetic variant-lung cancer association explained by the two

Trait- and density-mediated indirect interactions initiated by an exotic invasive plant autogenic ecosystem engineer

Science.gov (United States)

Dean E. Pearson

2010-01-01

Indirect interactions are important for structuring ecological systems. However, research on indirect effects has been heavily biased toward top-down trophic interactions, and less is known about other indirect-interaction pathways. As autogenic ecosystem engineers, plants can serve as initiators of nontrophic indirect interactions that, like top-down pathways, can...

Direct and Indirect Effects of Perceived Risk and Website Reputation on Purchase Intention: The Mediating Role of Online Trust

Directory of Open Access Journals (Sweden)

Chatpong Tangmanee

2016-10-01

Full Text Available Success in electronic commerce relies greatly on customer trust. While other studies have examined various factors affecting online customer trust, few have investigated the joint effects of perceived risk and website reputation on purchase intention using online trust as a mediator. The current study attempts to fill this gap. 300 online shoppers participated via web-based questionnaires using a quota sampling technique. Based on confirmatory factor analysis (CFA, our measurements were found to be valid and reliable. Using structural equation modeling (SEM, we confirmed significant direct effects of perceived risk and website reputation on customer purchase intentions. Furthermore, both factors had significant indirect effects on purchase intention through online trust. In addition to extending theoretical insight into online trust as a mediator for the effects of perceived risk and website reputation on purchase intention, web-based vendors may adopt the findings to adjust their online stores to raise customer trust and ultimately increase the possibility of online purchases.

The Indirect Effects of Servant Leadership Behavior on Organizational Citizenship Behavior and Job Performance: Organizational Justice as a Mediator

Directory of Open Access Journals (Sweden)

Cemal Zehir

2013-07-01

Full Text Available Therelationship between leader and followers plays a vital role, particularly ineducational institutions where a keen understanding of human character and highlevel of social interaction ought to be facilitated. For this reason, in starkcontrast to contemporary leaders who see people only as units of production orexpendable resources in a profit and loss statement, servant leadership focuseson meeting the needs of followers, making them reach their maximum potentialand so perform optimally in order to achieve organizational goals andobjectives. This study examines theeffects of servant leadership behaviors of private college principals onteachers’ organizationalcitizenship behavior and job performance. Using 300 respondents from theprivate education institutes in Turkey, servant leadership behavior is examinedfor its indirect effects on organizational citizenship behavior and jobperformance by its impact on organizational justice. Organizational justiceacts as a mediator between the variables in question. All the results are insupport of the studied mediation effects. Implications of the findings andsuggestions for future research are discussed

Climate-mediated competition in a high-elevation salamander community

Science.gov (United States)

Dallalio, Eric A.; Brand, Adrianne B,; Grant, Evan H. Campbell

2017-01-01

The distribution of the federally endangered Shenandoah Salamander (Plethodon shenandoah) is presumed to be limited by competition with the Red-backed Salamander (Plethodon cinereus). In particular, the current distribution of P. shenandoah is understood to be restricted to warmer and drier habitats because of interspecific interactions. These habitats may be particularly sensitive to climate change, though the influence of competition may also be affected by temperature and relative humidity. We investigated the response of P. shenandoah to competition with P. cinereus under four climate scenarios in 3-dimensional mesocosms. The results suggest that, although climate change may alleviate competitive pressure from P. cinereus, warmer temperatures may also significantly influence the persistence of the species across its known range.

Mediation analysis with multiple versions of the mediator.

Science.gov (United States)

Vanderweele, Tyler J

2012-05-01

The causal inference literature has provided definitions of direct and indirect effects based on counterfactuals that generalize the approach found in the social science literature. However, these definitions presuppose well-defined hypothetical interventions on the mediator. In many settings, there may be multiple ways to fix the mediator to a particular value, and these various hypothetical interventions may have very different implications for the outcome of interest. In this paper, we consider mediation analysis when multiple versions of the mediator are present. Specifically, we consider the problem of attempting to decompose a total effect of an exposure on an outcome into the portion through the intermediate and the portion through other pathways. We consider the setting in which there are multiple versions of the mediator but the investigator has access only to data on the particular measurement, not information on which version of the mediator may have brought that value about. We show that the quantity that is estimated as a natural indirect effect using only the available data does indeed have an interpretation as a particular type of mediated effect; however, the quantity estimated as a natural direct effect, in fact, captures both a true direct effect and an effect of the exposure on the outcome mediated through the effect of the version of the mediator that is not captured by the mediator measurement. The results are illustrated using 2 examples from the literature, one in which the versions of the mediator are unknown and another in which the mediator itself has been dichotomized.

Plant Community Richness Mediates Inhibitory Interactions and Resource Competition between Streptomyces and Fusarium Populations in the Rhizosphere.

Science.gov (United States)

Essarioui, Adil; LeBlanc, Nicholas; Kistler, Harold C; Kinkel, Linda L

2017-07-01

Plant community characteristics impact rhizosphere Streptomyces nutrient competition and antagonistic capacities. However, the effects of Streptomyces on, and their responses to, coexisting microorganisms as a function of plant host or plant species richness have received little attention. In this work, we characterized antagonistic activities and nutrient use among Streptomyces and Fusarium from the rhizosphere of Andropogon gerardii (Ag) and Lespedeza capitata (Lc) plants growing in communities of 1 (monoculture) or 16 (polyculture) plant species. Streptomyces from monoculture were more antagonistic against Fusarium than those from polyculture. In contrast, Fusarium isolates from polyculture had greater inhibitory capacities against Streptomyces than isolates from monoculture. Although Fusarium isolates had on average greater niche widths, the collection of Streptomyces isolates in total used a greater diversity of nutrients for growth. Plant richness, but not plant host, influenced the potential for resource competition between the two taxa. Fusarium isolates had greater niche overlap with Streptomyces in monoculture than polyculture, suggesting greater potential for Fusarium to competitively challenge Streptomyces in monoculture plant communities. In contrast, Streptomyces had greater niche overlap with Fusarium in polyculture than monoculture, suggesting that Fusarium experiences greater resource competition with Streptomyces in polyculture than monoculture. These patterns of competitive and inhibitory phenotypes among Streptomyces and Fusarium populations are consistent with selection for Fusarium-antagonistic Streptomyces populations in the presence of strong Fusarium resource competition in plant monocultures. Similarly, these results suggest selection for Streptomyces-inhibitory Fusarium populations in the presence of strong Streptomyces resource competition in more diverse plant communities. Thus, landscape-scale variation in plant species richness may be

Search Engine Competition with Network Externalities

NARCIS (Netherlands)

Argenton, C.; Prüfer, J.

2011-01-01

The market for Internet search is not only economically and socially important, it is also highly concentrated. Is this a problem? We study the question whether "competition is only a free click away". We argue that the market for Internet search is characterized by indirect network externalities

Performance of the Dutch non-life insurance industry: competition, efficiency and focus

NARCIS (Netherlands)

Bikker, J.A.; Gorter, J.

This paper investigates competition in the Dutch non-life insurance industry indirectly by measuring scale economies and X-inefficiency, assuming that strong competition would force insurance firms to exploit unused scale economies and to push down inefficiencies. We observe substantial economies of

Mediator effect of statistical process control between Total Quality Management (TQM) and business performance in Malaysian Automotive Industry

Science.gov (United States)

Ahmad, M. F.; Rasi, R. Z.; Zakuan, N.; Hisyamudin, M. N. N.

2015-12-01

In today's highly competitive market, Total Quality Management (TQM) is vital management tool in ensuring a company can success in their business. In order to survive in the global market with intense competition amongst regions and enterprises, the adoption of tools and techniques are essential in improving business performance. There are consistent results between TQM and business performance. However, only few previous studies have examined the mediator effect namely statistical process control (SPC) between TQM and business performance. A mediator is a third variable that changes the association between an independent variable and an outcome variable. This study present research proposed a TQM performance model with mediator effect of SPC with structural equation modelling, which is a more comprehensive model for developing countries, specifically for Malaysia. A questionnaire was prepared and sent to 1500 companies from automotive industry and the related vendors in Malaysia, giving a 21.8 per cent rate. Attempts were made at findings significant impact of mediator between TQM practices and business performance showed that SPC is important tools and techniques in TQM implementation. The result concludes that SPC is partial correlation between and TQM and BP with indirect effect (IE) is 0.25 which can be categorised as high moderator effect.

Practical guidance for conducting mediation analysis with multiple mediators using inverse odds ratio weighting.

Science.gov (United States)

Nguyen, Quynh C; Osypuk, Theresa L; Schmidt, Nicole M; Glymour, M Maria; Tchetgen Tchetgen, Eric J

2015-03-01

Despite the recent flourishing of mediation analysis techniques, many modern approaches are difficult to implement or applicable to only a restricted range of regression models. This report provides practical guidance for implementing a new technique utilizing inverse odds ratio weighting (IORW) to estimate natural direct and indirect effects for mediation analyses. IORW takes advantage of the odds ratio's invariance property and condenses information on the odds ratio for the relationship between the exposure (treatment) and multiple mediators, conditional on covariates, by regressing exposure on mediators and covariates. The inverse of the covariate-adjusted exposure-mediator odds ratio association is used to weight the primary analytical regression of the outcome on treatment. The treatment coefficient in such a weighted regression estimates the natural direct effect of treatment on the outcome, and indirect effects are identified by subtracting direct effects from total effects. Weighting renders treatment and mediators independent, thereby deactivating indirect pathways of the mediators. This new mediation technique accommodates multiple discrete or continuous mediators. IORW is easily implemented and is appropriate for any standard regression model, including quantile regression and survival analysis. An empirical example is given using data from the Moving to Opportunity (1994-2002) experiment, testing whether neighborhood context mediated the effects of a housing voucher program on obesity. Relevant Stata code (StataCorp LP, College Station, Texas) is provided. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Interventional effects for mediation analysis with multiple mediators

OpenAIRE

Vansteelandt, Stijn; Daniel, Rhian M.

2017-01-01

The mediation formula for the identification of natural (in)direct effects has facilitated mediation analyses that better respect the nature of the data, with greater consideration of the need for confounding control. The default assumptions on which it relies are strong, however. In particular, they are known to be violated when confounders of the mediator–outcome association are affected by the exposure. This complicates extensions of counterfactual-based mediation analysis to settings that...

An indecent proposal: the dual functions of indirect speech.

Science.gov (United States)

Chakroff, Aleksandr; Thomas, Kyle A; Haque, Omar S; Young, Liane

2015-01-01

People often use indirect speech, for example, when trying to bribe a police officer by asking whether there might be "a way to take care of things without all the paperwork." Recent game theoretic accounts suggest that a speaker uses indirect speech to reduce public accountability for socially risky behaviors. The present studies examine a secondary function of indirect speech use: increasing the perceived moral permissibility of an action. Participants report that indirect speech is associated with reduced accountability for unethical behavior, as well as increased moral permissibility and increased likelihood of unethical behavior. Importantly, moral permissibility was a stronger mediator of the effect of indirect speech on likelihood of action, for judgments of one's own versus others' unethical action. In sum, the motorist who bribes the police officer with winks and nudges may not only avoid public punishment but also maintain the sense that his actions are morally permissible. Copyright © 2014 Cognitive Science Society, Inc.

U.S. DOE indirect coal liquefaction program: An overview

Energy Technology Data Exchange (ETDEWEB)

Shen, J.; Schmetz, E.; Winslow, J.; Tischer, R. [Dept. of Energy, Germantown, MD (United States); Srivastava, R.

1997-12-31

Coal is the most abundant domestic energy resource in the United States. The Fossil Energy Organization within the US Department of Energy (DOE) has been supporting a coal liquefaction program to develop improved technologies to convert coal to clean and cost-effective liquid fuels to complement the dwindling supply of domestic petroleum crude. The goal of this program is to produce coal liquids that are competitive with crude at $20 to $25 per barrel. Indirect and direct liquefaction routes are the two technologies being pursued under the DOE coal liquefaction program. This paper will give an overview of the DOE indirect liquefaction program. More detailed discussions will be given to the F-T diesel and DME fuels which have shown great promises as clean burning alternative diesel fuels. The authors also will briefly discuss the economics of indirect liquefaction and the hurdles and opportunities for the early commercial deployment of these technologies. Discussions will be preceded by two brief reviews on the liquid versus gas phase reactors and the natural gas versus coal based indirect liquefaction.

Indirect radiative forcing by ion-mediated nucleation of aerosol

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F. Yu

2012-12-01

Full Text Available A clear understanding of particle formation mechanisms is critical for assessing aerosol indirect radiative forcing and associated climate feedback processes. Recent studies reveal the importance of ion-mediated nucleation (IMN in generating new particles and cloud condensation nuclei (CCN in the atmosphere. Here we implement the IMN scheme into the Community Atmosphere Model version 5 (CAM5. Our simulations show that, compared to globally averaged results based on H₂SO₄-H₂O binary homogeneous nucleation (BHN, the presence of ionization (i.e., IMN halves H₂SO₄ column burden, but increases the column integrated nucleation rate by around one order of magnitude, total particle number burden by a factor of ~3, CCN burden by ~10% (at 0.2% supersaturation to 65% (at 1.0% supersaturation, and cloud droplet number burden by ~18%. Compared to BHN, IMN increases cloud liquid water path by 7.5%, decreases precipitation by 1.1%, and increases total cloud cover by 1.9%. This leads to an increase of total shortwave cloud radiative forcing (SWCF by 3.67 W m⁻² (more negative and longwave cloud forcing by 1.78 W m⁻² (more positive, with large spatial variations. The effect of ionization on SWCF derived from this study (3.67 W m⁻² is a factor of ~3 higher that of a previous study (1.15 W m⁻² based on a different ion nucleation scheme and climate model. Based on the present CAM5 simulation, the 5-yr mean impacts of solar cycle induced changes in ionization rates on CCN and cloud forcing are small (~−0.02 W m⁻² but have larger inter-annual (from −0.18 to 0.17 W m⁻² and spatial variations.

Search engine competition with network externalities

NARCIS (Netherlands)

Argenton, C.; Prüfer, J.

2012-01-01

The market for Internet search is not only economically and socially important, it is also highly concentrated. Is this a problem? We study the question of whether “competition is only a free click away.” We argue that the market for Internet search is characterized by indirect network externalities

Development of an indirect competitive enzyme-linked immunosorbent assay applied to the Botrytis cinerea quantification in tissues of postharvest fruits

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Raba Julio

2011-10-01

Full Text Available Abstract Background Botrytis cinerea is a phytopathogenic fungus responsible for the disease known as gray mold, which causes substantial losses of fruits at postharvest. This fungus is present often as latent infection and an apparently healthy fruit can deteriorate suddenly due to the development of this infection. For this reason, rapid and sensitive methods are necessary for its detection and quantification. This article describes the development of an indirect competitive enzyme-linked immunosorbent assay (ELISA for quantification of B. cinerea in apple (Red Delicious, table grape (pink Moscatel, and pear (William's tissues. Results The method was based in the competition for the binding site of monoclonal antibodies between B. cinerea antigens present in fruit tissues and B. cinerea purified antigens immobilized by a crosslinking agent onto the surface of the microtiter plates. The method was validated considering parameters such as selectivity, linearity, precision, accuracy and sensibility. The calculated detection limit was 0.97 μg mL-1 B. cinerea antigens. The immobilized antigen was perfectly stable for at least 4 months assuring the reproducibility of the assay. The fungus was detected and quantified in any of the fruits tested when the rot was not visible yet. Results were compared with a DNA quantification method and these studies showed good correlation. Conclusions The developed method allowed detects the presence of B. cinerea in asymptomatic fruits and provides the advantages of low cost, easy operation, and short analysis time determination for its possible application in the phytosanitary programs of the fruit industry worldwide.

School leadership effects revisited: a review of empirical studies guided by indirect-effect models

NARCIS (Netherlands)

Hendriks, Maria A.; Scheerens, Jaap

2013-01-01

Fourteen leadership effect studies that used indirect-effect models were quantitatively analysed to explore the most promising mediating variables. The results indicate that total effect sizes based on indirect-effect studies appear to be low, quite comparable to the results of some meta-analyses of

Tax competition and tax harmonization in the European Union

Directory of Open Access Journals (Sweden)

Danuše Nerudová

2004-01-01

Full Text Available The article deals with the problems of tax competition and harmonization within the European Union. It reveals the single difficulties connected with harmonization, identifies the problems arising from tax competition and points out the harmful tax competition as well. Single compulsory harmonized tax base in connection with prevailing tax competition in the area of tax rates is the suggested solution in the scope of direct taxation. As the solution in the area of indirect taxation could serve the introduction of “principle of origin”. This would cause remarkable administrative costs decrease not only for economic subjects but for tax authorities as well.

Mediation Analysis: A Practitioner's Guide.

Science.gov (United States)

VanderWeele, Tyler J

2016-01-01

This article provides an overview of recent developments in mediation analysis, that is, analyses used to assess the relative magnitude of different pathways and mechanisms by which an exposure may affect an outcome. Traditional approaches to mediation in the biomedical and social sciences are described. Attention is given to the confounding assumptions required for a causal interpretation of direct and indirect effect estimates. Methods from the causal inference literature to conduct mediation in the presence of exposure-mediator interactions, binary outcomes, binary mediators, and case-control study designs are presented. Sensitivity analysis techniques for unmeasured confounding and measurement error are introduced. Discussion is given to extensions to time-to-event outcomes and multiple mediators. Further flexible modeling strategies arising from the precise counterfactual definitions of direct and indirect effects are also described. The focus throughout is on methodology that is easily implementable in practice across a broad range of potential applications.

Hostile sexism (de)motivates women's social competition intentions: The contradictory role of emotions.

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Lemonaki, Elena; Manstead, Antony S R; Maio, Gregory R

2015-09-01

In the present research, we examine the ways in which exposure to hostile sexism influences women's competitive collective action intentions. Prior to testing our main model, our first study experimentally induced high versus low levels of security-comfort with the aim of providing experimental evidence for the proposed causal link between these emotions and intentions to engage in social competition. Results showed that lower levels of security-comfort reduced women's readiness to compete socially with men. Experiment 2 investigated the effect of hostile sexism on women's emotional reactions and readiness to engage in social competition. Consistent with the proposed model, results showed that exposure to hostile beliefs about women (1) increased anger-frustration and (2) decreased security-comfort. More specifically, exposure to hostile sexism had a positive indirect effect on social competition intentions through anger-frustration, and a negative indirect effect through security-comfort. © 2015 The British Psychological Society.

Bacteriocin-mediated competition in cystic fibrosis lung infections

DEFF Research Database (Denmark)

Ghoul, Melanie; West, Stuart A.; Johansen, Helle Krogh

2015-01-01

Bacteriocins are toxins produced by bacteria to kill competitors of the same species. Theory and laboratory experiments suggest that bacteriocin production and immunity play a key role in the competitive dynamics of bacterial strains. The extent to which this is the case in natural populations......, especially human pathogens, remains to be tested. We examined the role of bacteriocins in competition using Pseudomonas aeruginosa strains infecting lungs of humans with cystic fibrosis (CF). We assessed the ability of different strains to kill each other using phenotypic assays, and sequenced their genomes...

Winning the competition for supplier resources: The role of preferential resource allocation from suppliers

NARCIS (Netherlands)

Pulles, Niels Jaring; Veldman, Jasper; Schiele, Holger

2016-01-01

Purpose This paper examines the competition between buying firms for the supplier’s competitive resources. The purpose of this paper is to examine how indirect capabilities – the ability to access external resources – can help in obtaining preferential resource allocation from suppliers.

University Mergers in Finland: Mediating Global Competition

Science.gov (United States)

Välimaa, Jussi; Aittola, Helena; Ursin, Jani

2014-01-01

University mergers have become a common strategy for increasing global competitiveness. In this chapter, the authors analyze the implementation of mergers in Finnish universities from the perspective of social justice as conceived within Finland and other Nordic countries.

Target mediated drug disposition with drug-drug interaction, Part II: competitive and uncompetitive cases.

Science.gov (United States)

Koch, Gilbert; Jusko, William J; Schropp, Johannes

2017-02-01

We present competitive and uncompetitive drug-drug interaction (DDI) with target mediated drug disposition (TMDD) equations and investigate their pharmacokinetic DDI properties. For application of TMDD models, quasi-equilibrium (QE) or quasi-steady state (QSS) approximations are necessary to reduce the number of parameters. To realize those approximations of DDI TMDD models, we derive an ordinary differential equation (ODE) representation formulated in free concentration and free receptor variables. This ODE formulation can be straightforward implemented in typical PKPD software without solving any non-linear equation system arising from the QE or QSS approximation of the rapid binding assumptions. This manuscript is the second in a series to introduce and investigate DDI TMDD models and to apply the QE or QSS approximation.

Direct and Indirect Effects of PM on the Cardiovascular System

Science.gov (United States)

Nelin, Timothy D.; Joseph, Allan M.; Gorr, Matthew W.; Wold, Loren E.

2011-01-01

Human exposure to particulate matter (PM) elicits a variety of responses on the cardiovascular system through both direct and indirect pathways. Indirect effects of PM on the cardiovascular system are mediated through the autonomic nervous system, which controls heart rate variability, and inflammatory responses, which augment acute cardiovascular events and atherosclerosis. Recent research demonstrates that PM also affects the cardiovascular system directly by entry into the systemic circulation. This process causes myocardial dysfunction through mechanisms of reactive oxygen species production, calcium ion interference, and vascular dysfunction. In this review, we will present key evidence in both the direct and indirect pathways, suggest clinical applications of the current literature, and recommend directions for future research. PMID:22119171

CD4+ T cell-mediated rejection of MHC class II-positive tumor cells is dependent on antigen secretion and indirect presentation on host APCs.

Science.gov (United States)

Haabeth, Ole Audun Werner; Fauskanger, Marte; Manzke, Melanie; Lundin, Katrin U; Corthay, Alexandre; Bogen, Bjarne; Tveita, Anders Aune

2018-05-11

Tumor-specific CD4+ T cells have been shown to mediate efficient anti-tumor immune responses against cancer. Such responses can occur through direct binding to MHC class II (MHC II)-expressing tumor cells or indirectly via activation of professional antigen-presenting cells (APC) that take up and present the tumor antigen. We have previously shown that CD4+ T cells reactive against an epitope within the Ig light chain variable region of a murine B cell lymphoma can reject established tumors. Given the presence of MHC II molecules at the surface of lymphoma cells, we investigated whether MHC II-restricted antigen presentation on tumor cells alone was required for rejection. Variants of the A20 B lymphoma cell line that either secreted or intracellularly retained different versions of the tumor-specific antigen revealed that antigen secretion by the MHC II-expressing tumor cells was essential both for the priming and effector phase of CD4+ T cell-driven anti-tumor immune responses. Consistent with this, genetic ablation of MHC II in tumor cells, both in the case of B lymphoma and B16 melanoma, did not preclude rejection of tumors by tumor antigen-specific CD4+ T cells in vivo. These findings demonstrate that MHC class II expression on tumor cells themselves is not required for CD4+ T cell-mediated rejection, and that indirect display on host APC is sufficient for effective tumor elimination. These results support the importance of tumor-infiltrating APC as mediators of tumor cell killing by CD4+ T cells. Copyright ©2018, American Association for Cancer Research.

Effects of competitive pressure on expert performance: underlying psychological, physiological, and kinematic mechanisms.

Science.gov (United States)

Cooke, Andrew; Kavussanu, Maria; McIntyre, David; Boardley, Ian D; Ring, Christopher

2011-08-01

Although it is well established that performance is influenced by competitive pressure, our understanding of the mechanisms which underlie the pressure-performance relationship is limited. The current experiment examined mediators of the relationship between competitive pressure and motor skill performance of experts. Psychological, physiological, and kinematic responses to three levels of competitive pressure were measured in 50 expert golfers, during a golf putting task. Elevated competitive pressure increased putting accuracy, anxiety, effort, and heart rate, but decreased grip force. Quadratic effects of pressure were noted for self-reported conscious processing and impact velocity. Mediation analyses revealed that effort and heart rate partially mediated improved performance. The findings indicate that competitive pressure elicits effects on expert performance through both psychological and physiological pathways. Copyright © 2011 Society for Psychophysiological Research.

Direct and indirect influences of fate control belief, gambling expectancy bias, and self-efficacy on problem gambling and negative mood among Chinese college students: a multiple mediation analysis.

Science.gov (United States)

Tang, Catherine So-Kum; Wu, Anise M S

2010-12-01

A multiple mediation model was proposed to integrate core concepts of the social axioms framework and the social cognitive theory in order to understand gambling behavior. It was hypothesized that the influence of general fate control belief on problem gambling and negative mood would be mediated by gambling-specific beliefs. Data from 773 Chinese college recreational gamblers were collected. The bootstrapping procedure was used to test the multiple mediation hypotheses. Significant indirect effects of fate control belief on problem gambling and negative mood through two gambling-specific mediators were found. Gambling expectancy bias was a more salient mediator than gambling self-efficacy. Fate control belief was also found to have a significant direct effect on negative mood. In general, a high level of general fate control belief was related to greater gambling expectancy bias and lower self-efficacy in resisting gambling, which were in turn related to problem gambling and negative mood. Limitations and implications of the study were discussed.

Tolerance to bovine clinical mastitis: Total, direct, and indirect milk losses.

Science.gov (United States)

Detilleux, J

2018-04-01

The objectives of this paper were to estimate direct and indirect milk losses associated with mastitis. Indirect losses, linked to indirect tolerance, are mediated by the increase in milk somatic cell count (SCC) in response to bacterial infection. Direct losses, linked to weak direct tolerance, are not mediated by the increase in SCC. So far, studies have evaluated milk loss associated with clinical mastitis without considering both components, which may lead to biased estimates of their sum; that is, the total loss in milk. A total of 43,903 test-day records on milk and SCC from 3,716 cows and 5,858 lactations were analyzed with mediation mixed models and health trajectories to estimate the amount of direct, indirect, and total milk losses after adjustment for known and potentially unmeasured (sensitivity analyses) confounding factors. Estimates were formalized under the counterfactual causal theory of causation. In this study, milk losses were mostly mediated by an increase in SCC. They were highest in the first month of lactation, when SCC were highest. Milk losses were estimated at 0.5, 0.8, and 1.1 kg/d in first, second, and third and greater parity, respectively. Two phases described how changes in milk were associated with changes in SCC: on average, one occurred before and one after the day preceding the clinical diagnosis. In both phases, changes in milk were estimated at 1 mg/d per 10 3 cells/mL. After adjusting for known confounders, cow effect accounted for 20.7 and 64.2% of the variation in milk in the first and second phases, respectively. This suggests that deviations from the resilient path were highest during the second phase of inflammation and that selection for cows more tolerant to mastitis is feasible. As discussed herein, epigenetic regulation of macrophage polarization may contribute to the variation in milk observed in the second phase. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Two-condition within-participant statistical mediation analysis: A path-analytic framework.

Science.gov (United States)

Montoya, Amanda K; Hayes, Andrew F

2017-03-01

Researchers interested in testing mediation often use designs where participants are measured on a dependent variable Y and a mediator M in both of 2 different circumstances. The dominant approach to assessing mediation in such a design, proposed by Judd, Kenny, and McClelland (2001), relies on a series of hypothesis tests about components of the mediation model and is not based on an estimate of or formal inference about the indirect effect. In this article we recast Judd et al.'s approach in the path-analytic framework that is now commonly used in between-participant mediation analysis. By so doing, it is apparent how to estimate the indirect effect of a within-participant manipulation on some outcome through a mediator as the product of paths of influence. This path-analytic approach eliminates the need for discrete hypothesis tests about components of the model to support a claim of mediation, as Judd et al.'s method requires, because it relies only on an inference about the product of paths-the indirect effect. We generalize methods of inference for the indirect effect widely used in between-participant designs to this within-participant version of mediation analysis, including bootstrap confidence intervals and Monte Carlo confidence intervals. Using this path-analytic approach, we extend the method to models with multiple mediators operating in parallel and serially and discuss the comparison of indirect effects in these more complex models. We offer macros and code for SPSS, SAS, and Mplus that conduct these analyses. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Are competition and extrinsic motivation reliable predictors of academic cheating?

OpenAIRE

Gábor eOrosz; Gábor eOrosz; Gábor eOrosz; Dávid eFarkas; Dávid eFarkas; Dávid eFarkas; Christine eRoland-Levy

2013-01-01

Previous studies suggest that extrinsic motivation and competition are reliable predictors of academic cheating. The aim of the present questionnaire study was to separate the effects of motivation- and competition-related variables on academic cheating by Hungarian high school students (N = 620, M = 264, F = 356). Structural equation modeling showed that intrinsic motivation has a negative effect, and amotivation has a positive indirect effect on self-reported academic cheating. In contrast,...

Competition, Innovation, Risk-Taking, and Profitability in the Chinese Banking Sector: An Empirical Analysis Based on Structural Equation Modeling

Directory of Open Access Journals (Sweden)

Ti Hu

2016-01-01

Full Text Available We introduce a new perspective to systematically investigate the cause-and-effect relationships among competition, innovation, risk-taking, and profitability in the Chinese banking industry. Our hypotheses are tested by the structural equation modeling (SEM, and the empirical results show that (i risk-taking is positively related to profitability; (ii innovation positively affects both risk-taking and profitability, and the effect of innovation on profitability works both directly and indirectly; (iii competition negatively affects risk-taking but positively affects both innovation and profitability, and the effects of competition on risk-taking and profitability work both directly and indirectly; (iv there is a cascading relationship among market competition and bank innovation, risk-taking, and profitability.

Identification of Indirect Effects in a Cognitive Patient Education (COPE) Intervention for Low Back Pain.

Science.gov (United States)

Mansell, Gemma; Storheim, Kjersti; Løchting, Ida; Werner, Erik L; Grotle, Margreth

2017-12-01

Many interventions for the treatment of low back pain exist, but the mechanisms through which such treatments work are not always clear. This situation is especially true for biopsychosocial interventions that incorporate several different components and methods of delivery. The study objective was to examine the indirect effects of the Cognitive Patient Education (COPE) intervention via illness perceptions, back pain myths, and pain catastrophizing on disability outcome. This study was a secondary analysis of the COPE randomized controlled trial. Mediation analysis techniques were employed to examine the indirect effects of the COPE intervention via residualized change (baseline - posttreatment) in the 3 variables hypothesized to be targeted by the COPE intervention on posttreatment disability outcome. Pain intensity at baseline, pain duration, clinician type, and a treatment-mediator interaction term were controlled for in the analysis. Preliminary analyses confirmed that changes in pain catastrophizing and illness perceptions (not back pain myths) were related to both allocation to the intervention arm and posttreatment disability score. The treatment exerted statistically significant indirect effects via changes in illness perceptions and pain catastrophizing on posttreatment disability score (illness perceptions standardized indirect effect = 0.09 [95% CI = 0.03 to 0.16]; pain catastrophizing standardized indirect effect = 0.05 [95% CI = 0.01 to 0.12]). However, the inclusion of an interaction term led to the indirect effects being significantly reduced, with the effects no longer being statistically significant. This study presents a secondary analysis of variables not identified a priori as being potentially important treatment targets; other, unmeasured factors could also be important in explaining treatment effects. The finding that small indirect effects of the COPE intervention via changes in illness perceptions and pain catastrophizing on posttreatment

Oxalomalate, a competitive inhibitor of NADP+ -dependent isocitrate dehydrogenase, regulates lipid peroxidation-mediated apoptosis in U937 cells.

Science.gov (United States)

Yang, Eun Sun; Yang, Joon-Hyuck; Park, Ji Eun; Park, Jeen-Woo

2005-01-01

Membrane lipid peroxidation processes yield products that may react with DNA and proteins to cause oxidative modifications. Recently, we demonstrated that the control of cytosolic redox balance and the cellular defense against oxidative damage is one of the primary functions of cytosolic NADP+ -dependent isocitrate dehydrogenase (IDPc) through to supply NADPH for antioxidant systems. The protective role of IDPc against lipid peroxidation-mediated apoptosis in U937 cells was investigated in control and cells pre-treated with oxlalomalate, a competitive inhibitor of IDPc. Upon exposure to 2,2'-azobis (2-amidinopropane) hydrochloride (AAPH) to U937 cells, which induces lipid peroxidation in membranes, the susceptibility to apoptosis was higher in oxalomalate-treated cells as compared to control cells. The results suggest that IDPc plays an important protective role in apoptosis of U937 cells induced by lipid peroxidation-mediated oxidative stress.

Mediation analysis with multiple versions of the mediator

OpenAIRE

VanderWeele, Tyler J.

2012-01-01

The causal inference literature has provided definitions of direct and indirect effects based on counterfactuals that generalize the approach found in the social science literature. However, these definitions presuppose well defined hypothetical interventions on the mediator. In many settings there may be multiple ways to fix the mediator to a particular value and these different hypothetical interventions may have very different implications for the outcome of interest. In this paper we cons...

Serobactins-mediated iron acquisition systems optimize competitive fitness of Herbaspirillum seropedicae inside rice plants.

Science.gov (United States)

Rosconi, Federico; Trovero, María F; de Souza, Emanuel M; Fabiano, Elena

2016-09-01

Herbaspirillum seropedicae Z67 is a diazotrophic endophyte able to colonize the interior of many economically relevant crops such as rice, wheat, corn and sorghum. Under iron-deficient conditions, this organism secretes serobactins, a suite of lipopetide siderophores. The role of siderophores in the interaction between endophytes and their plant hosts are not well understood. In this work, we aimed to determine the importance of serobactins-mediated iron acquisition systems in the interaction of H. seropedicae with rice plants. First we provide evidence, by using a combination of genome analysis, proteomic and genetic studies, that the Hsero_2345 gene encodes a TonB-dependent receptor involved in iron-serobactin complex internalization when iron bioavailability is low. Our results show that survival of the Hsero_2345 mutant inside rice plants was not significantly different from that of the wild-type strain. However, when plants were co-inoculated at equal ratios with the wild-type strain and with a double mutant defective in serobactins synthesis and internalization, recovery of mutant was significantly impaired after 8 days post-inoculation. These results demonstrate that serobactins-mediated iron acquisition contributes to competitive fitness of H. seropedicae inside host plants. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Total, direct, and indirect effects of paan on oral cancer.

Science.gov (United States)

Merchant, Anwar T; Pitiphat, Waranuch

2015-03-01

Paan (betel leaf and betel nut quid) used with or without tobacco has been positively associated with oral cancer. Oral submucous fibrosis (OSMF), a precancerous condition caused by paan, lies on the causal pathway between paan use and oral cancer. The purpose of this analysis was to estimate the effect of paan consumption on oral cancer risk when it is mediated by OSMF. We used mediation methods proposed by VanderWeele, which are based on causal inference principles, to characterize the total, direct, and indirect effects of paan, consumed with and without tobacco, on oral cancer mediated by OSMF. We reanalyzed case-control data collected from three hospitals in Karachi, Pakistan, between July 1996 and March 1998. For paan without tobacco, the total effect on oral cancer was OR 7.39, 95 % CI 1.01, 38.11, the natural indirect effect (due to OSMF among paan users) was OR 2.48, 95 % CI 0.99, 10.44, and the natural direct effect (due to paan with OSMF absent) was OR 3.32, 95 % CI 0.68, 10.07. For paan with tobacco, the total direct effect was OR 15.68, 95 % CI 3.00, 54.90, the natural indirect effect was OR 2.18, 95 % CI 0.82, 5.52, and the natural direct effect was OR 7.27, 95 % CI 2.15, 20.43. Paan, whether or not it contained tobacco, raised oral cancer risk irrespective of OSMF. Oral cancer risk was higher among those who used paan with tobacco.

Preschool children's behavioral tendency toward social indirect reciprocity.

Directory of Open Access Journals (Sweden)

Mayuko Kato-Shimizu

Full Text Available Social indirect reciprocity seems to be crucial in enabling large-scale cooperative networks among genetically unrelated individuals in humans. However, there are relatively few studies on social indirect reciprocity in children compared to adults. Investigating whether young children have a behavioral tendency toward social indirect reciprocity will help us understand how and when the fundamental ability to form cooperative relationships among adults is acquired. Using naturalistic observation at a nursery school, this study examined whether 5- to 6-year-olds show a behavioral tendency to engage in social indirect reciprocity in response to their peers' prosocial behavior toward a third party. The results revealed that bystander children tended to display prosocial behavior toward their peers more frequently after observing these peers' prosocial behavior toward third-party peers, compared with control situations; this suggests that 5- to 6-year-olds may have an essential behavioral tendency to establish social indirect reciprocity when interacting with peers in their daily lives. In addition, bystanders tended to display affiliative behavior after observing focal children's prosocial behavior. In other words, observing peers' prosocial behavior toward third-party peers evoked bystanders' positive emotions toward the helpers. Considering both the present results and previous findings, we speculate that in preschoolers, such positive emotions might mediate the increase in the bystander's prosocial behavior toward the helper. In addition, an intuitional emotional process plays an important role in the preschooler's behavioral tendency toward social indirect reciprocity in natural interactions with peers.

Preschool children's behavioral tendency toward social indirect reciprocity.

Science.gov (United States)

Kato-Shimizu, Mayuko; Onishi, Kenji; Kanazawa, Tadahiro; Hinobayashi, Toshihiko

2013-01-01

Social indirect reciprocity seems to be crucial in enabling large-scale cooperative networks among genetically unrelated individuals in humans. However, there are relatively few studies on social indirect reciprocity in children compared to adults. Investigating whether young children have a behavioral tendency toward social indirect reciprocity will help us understand how and when the fundamental ability to form cooperative relationships among adults is acquired. Using naturalistic observation at a nursery school, this study examined whether 5- to 6-year-olds show a behavioral tendency to engage in social indirect reciprocity in response to their peers' prosocial behavior toward a third party. The results revealed that bystander children tended to display prosocial behavior toward their peers more frequently after observing these peers' prosocial behavior toward third-party peers, compared with control situations; this suggests that 5- to 6-year-olds may have an essential behavioral tendency to establish social indirect reciprocity when interacting with peers in their daily lives. In addition, bystanders tended to display affiliative behavior after observing focal children's prosocial behavior. In other words, observing peers' prosocial behavior toward third-party peers evoked bystanders' positive emotions toward the helpers. Considering both the present results and previous findings, we speculate that in preschoolers, such positive emotions might mediate the increase in the bystander's prosocial behavior toward the helper. In addition, an intuitional emotional process plays an important role in the preschooler's behavioral tendency toward social indirect reciprocity in natural interactions with peers.

Are Competition and Extrinsic Motivation Reliable Predictors of Academic Cheating?

OpenAIRE

Orosz, G?bor; Farkas, D?vid; Roland-L?vy, Christine

2013-01-01

Previous studies suggest that extrinsic motivation and competition are reliable predictors of academic cheating. The aim of the present questionnaire study was to separate the effects of motivation- and competition-related variables on academic cheating by Hungarian high school students (N = 620, M = 264, F = 356). Structural equation modeling showed that intrinsic motivation has a negative effect, and amotivation has a positive indirect effect on self-reported academic cheating. In contrast,...

Development of Indirect Competitive Immuno-Assay Method Using SPR Detection for Rapid and Highly Sensitive Measurement of Salivary Cortisol Levels

International Nuclear Information System (INIS)

Tahara, Yusuke; Huang, Zhe; Kiritoshi, Tetsuro; Onodera, Takeshi; Toko, Kiyoshi

2014-01-01

The monitoring of salivary cortisol as a key biomarker of an individual’s stress response has been increasingly focused on. This paper describes the development of a novel cortisol immuno-assay method based on an indirect competitive method using a commercially available surface plasmon resonance instrument. The surface of an Au chip was modified with PEG6-COOH aromatic dialkanethiol self-assembled monolayers and hydrocortisone 3-(O-carboxymethyl) oxime (hydrocortisone 3-CMO) as a cortisol analog. A detection limit of 38 ppt range with a measurement range of 10 ppt–100 ppb was accomplished without the incubation of a mixing solution consisting of standard cortisol and an anti-cortisol antibody, and the time for quantification of cortisol concentration was 8 min from the sample injection. We experimentally compared our immuno-assay with a commercialized salivary cortisol enzyme-linked immunosorbent assay (ELISA) kit using human saliva samples. It was found that the results obtained by the cortisol immuno-assay had a good correlation with those obtained by ELISA assay (R = 0.96). Our findings indicate the potential utility of the cortisol immuno-assay for measurements of human salivary cortisol levels.

Development of Indirect Competitive Immuno-Assay Method Using SPR Detection for Rapid and Highly Sensitive Measurement of Salivary Cortisol Levels

Energy Technology Data Exchange (ETDEWEB)

Tahara, Yusuke; Huang, Zhe; Kiritoshi, Tetsuro [Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka (Japan); Onodera, Takeshi [Research and Development Center for Taste and Odor Sensing, Kyushu University, Fukuoka (Japan); Toko, Kiyoshi, E-mail: toko@ed.kyushu-u.ac.jp [Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka (Japan); Research and Development Center for Taste and Odor Sensing, Kyushu University, Fukuoka (Japan)

2014-05-30

The monitoring of salivary cortisol as a key biomarker of an individual’s stress response has been increasingly focused on. This paper describes the development of a novel cortisol immuno-assay method based on an indirect competitive method using a commercially available surface plasmon resonance instrument. The surface of an Au chip was modified with PEG6-COOH aromatic dialkanethiol self-assembled monolayers and hydrocortisone 3-(O-carboxymethyl) oxime (hydrocortisone 3-CMO) as a cortisol analog. A detection limit of 38 ppt range with a measurement range of 10 ppt–100 ppb was accomplished without the incubation of a mixing solution consisting of standard cortisol and an anti-cortisol antibody, and the time for quantification of cortisol concentration was 8 min from the sample injection. We experimentally compared our immuno-assay with a commercialized salivary cortisol enzyme-linked immunosorbent assay (ELISA) kit using human saliva samples. It was found that the results obtained by the cortisol immuno-assay had a good correlation with those obtained by ELISA assay (R = 0.96). Our findings indicate the potential utility of the cortisol immuno-assay for measurements of human salivary cortisol levels.

Immunologically mediated oral diseases

OpenAIRE

Jimson, Sudha; Balachader, N.; Anita, N.; Babu, R.

2015-01-01

Immune mediated diseases of oral cavity are uncommon. The lesions may be self-limiting and undergo remission spontaneously. Among the immune mediated oral lesions the most important are lichen planus, pemphigus, erythema multiformi, epidermolysis bullosa, systemic lupus erythematosis. Cellular and humoral mediated immunity play a major role directed against epithelial and connective tissue in chronic and recurrent patterns. Confirmatory diagnosis can be made by biopsy, direct and indirect imm...

Color indirect effects on melatonin regulation

Science.gov (United States)

Mian, Tian; Liu, Timon C.; Li, Yan

2002-04-01

Color indirect effect (CIE) is referred to as the physiological and psychological effects of color resulting from color vision. In previous papers, we have studied CIE from the viewpoints of the integrated western and Chinese traditional medicine, put forward the color-autonomic- nervous-subsystem model (CAM), and provided its time-theory foundation. In this paper, we applied it to study light effects on melatonin regulation in humans, and suggested that it is CIE that mediates light effects on melatonin suppression.

Immune-mediated competition in rodent malaria is most likely caused by induced changes in innate immune clearance of merozoites.

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Jayanthi Santhanam

2014-01-01

Full Text Available Malarial infections are often genetically diverse, leading to competitive interactions between parasites. A quantitative understanding of the competition between strains is essential to understand a wide range of issues, including the evolution of virulence and drug resistance. In this study, we use dynamical-model based Bayesian inference to investigate the cause of competitive suppression of an avirulent clone of Plasmodium chabaudi (AS by a virulent clone (AJ in immuno-deficient and competent mice. We test whether competitive suppression is caused by clone-specific differences in one or more of the following processes: adaptive immune clearance of merozoites and parasitised red blood cells (RBCs, background loss of merozoites and parasitised RBCs, RBC age preference, RBC infection rate, burst size, and within-RBC interference. These processes were parameterised in dynamical mathematical models and fitted to experimental data. We found that just one parameter μ, the ratio of background loss rate of merozoites to invasion rate of mature RBCs, needed to be clone-specific to predict the data. Interestingly, μ was found to be the same for both clones in single-clone infections, but different between the clones in mixed infections. The size of this difference was largest in immuno-competent mice and smallest in immuno-deficient mice. This explains why competitive suppression was alleviated in immuno-deficient mice. We found that competitive suppression acts early in infection, even before the day of peak parasitaemia. These results lead us to argue that the innate immune response clearing merozoites is the most likely, but not necessarily the only, mediator of competitive interactions between virulent and avirulent clones. Moreover, in mixed infections we predict there to be an interaction between the clones and the innate immune response which induces changes in the strength of its clearance of merozoites. What this interaction is unknown, but

An Indirect Defence Trait Mediated through Egg-Induced Maize Volatiles from Neighbouring Plants.

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Daniel M Mutyambai

Full Text Available Attack of plants by herbivorous arthropods may result in considerable changes to the plant's chemical phenotype with respect to emission of herbivore-induced plant volatiles (HIPVs. These HIPVs have been shown to act as repellents to the attacking insects as well as attractants for the insects antagonistic to these herbivores. Plants can also respond to HIPV signals from other plants that warn them of impending attack. Recent investigations have shown that certain maize varieties are able to emit volatiles following stemborer egg deposition. These volatiles attract the herbivore's parasitoids and directly deter further oviposition. However, it was not known whether these oviposition-induced maize (Zea mays, L. volatiles can mediate chemical phenotypic changes in neighbouring unattacked maize plants. Therefore, this study sought to investigate the effect of oviposition-induced maize volatiles on intact neighbouring maize plants in 'Nyamula', a landrace known to respond to oviposition, and a standard commercial hybrid, HB515, that did not. Headspace volatile samples were collected from maize plants exposed to Chilo partellus (Swinhoe (Lepidoptera: Crambidae egg deposition and unoviposited neighbouring plants as well as from control plants kept away from the volatile emitting ones. Behavioural bioassays were carried out in a four-arm olfactometer using egg (Trichogramma bournieri Pintureau & Babault (Hymenoptera: Trichogrammatidae and larval (Cotesia sesamiae Cameron (Hymenoptera: Braconidae parasitoids. Coupled Gas Chromatography-Mass Spectrometry (GC-MS was used for volatile analysis. For the 'Nyamula' landrace, GC-MS analysis revealed HIPV production not only in the oviposited plants but also in neighbouring plants not exposed to insect eggs. Higher amounts of EAG-active biogenic volatiles such as (E-4,8-dimethyl-1,3,7-nonatriene were emitted from these plants compared to control plants. Subsequent behavioural assays with female T. bournieri and

Indirect evolution of social fitness inequalities and facultative social exploitation.

Science.gov (United States)

Nair, Ramith R; Fiegna, Francesca; Velicer, Gregory J

2018-03-28

Microbial genotypes with similarly high proficiency at a cooperative behaviour in genetically pure groups often exhibit fitness inequalities caused by social interaction in mixed groups. Winning competitors in this scenario have been referred to as 'cheaters' in some studies. Such interaction-specific fitness inequalities, as well as social exploitation (in which interaction between genotypes increases absolute fitness), might evolve due to selection for competitiveness at the focal behaviour or might arise non-adaptively due to pleiotropy, hitchhiking or genetic drift. The bacterium Myxococcus xanthus sporulates during cooperative development of multicellular fruiting bodies. Using M. xanthus lineages that underwent experimental evolution in allopatry without selection on sporulation, we demonstrate that interaction-specific fitness inequalities and facultative social exploitation during development readily evolved indirectly among descendant lineages. Fitness inequalities between evolved genotypes were not caused by divergence in developmental speed, as faster-developing strains were not over-represented among competition winners. In competitions between ancestors and several evolved strains, all evolved genotypes produced more spores than the ancestors, including losers of evolved-versus-evolved competitions, indicating that adaptation in non-developmental contexts pleiotropically increased competitiveness for spore production. Overall, our results suggest that fitness inequalities caused by social interaction during cooperative processes may often evolve non-adaptively in natural populations. © 2018 The Authors.

Quality Response and Competitiveness of Fish Exports in Oman

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L. Zaibet

2000-06-01

Full Text Available Received trade theory presumes an important role for increasing returns to scale, product-differentiation, and quality as determinants of trade flows. In a global world, exports can only be expanded if a nation is competitive in terms of cost and quality of traded products. Food safety and quality systems, such as HACCP or ISO 9000, are indirectly included in international agreements (GATT as facilitators of trade. These systems may lead to cost leadership and product improvement, which are key factors to higher competitiveness and sustained benefits in international markets. This paper estimates a modified Armington model that links product differentiation and safety programs to market shares, i.e. competitiveness.

Drinking Games as a Venue for Sexual Competition

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Liana S. E. Hone

2013-10-01

Full Text Available Based on sexual selection theory, we hypothesized that sex differences in mating effort and social competitiveness—and subsequent sex differences in sexual and competitive motivations for participating in drinking games—are responsible for the well-documented sex differences in college students' drinking game behaviors. Participants in a cross-sectional study were 351 women and 336 men aged 17 to 26. In a mediation model, we tested sex differences in mating effort, social competitiveness, sexual and competitive motivations for participating in drinking games, drinking game behaviors, and alcohol-related problems. Men participated in drinking games more frequently, consumed more alcohol while participating in drinking games, and experienced more problems associated with drinking. These sex differences appeared to be partially mediated by mating effort, social competitiveness, and sexual and competitive motivations for participating in drinking games. Drinking games are a major venue in which college students engage in heavy episodic drinking, which is a risk factor for college students' behavioral and health problems. Thus, the functional perspective we used to analyze them here may help to inform public health and university interventions and enable better identification of at-risk students.

Intraspecies Competition in Serratia marcescens Is Mediated by Type VI-Secreted Rhs Effectors and a Conserved Effector-Associated Accessory Protein.

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Alcoforado Diniz, Juliana; Coulthurst, Sarah J

2015-07-01

The type VI secretion system (T6SS) is widespread in Gram-negative bacteria and can deliver toxic effector proteins into eukaryotic cells or competitor bacteria. Antibacterial T6SSs are increasingly recognized as key mediators of interbacterial competition and may contribute to the outcome of many polymicrobial infections. Multiple antibacterial effectors can be delivered by these systems, with diverse activities against target cells and distinct modes of secretion. Polymorphic toxins containing Rhs repeat domains represent a recently identified and as-yet poorly characterized class of T6SS-dependent effectors. Previous work had revealed that the potent antibacterial T6SS of the opportunistic pathogen Serratia marcescens promotes intraspecies as well as interspecies competition (S. L. Murdoch, K. Trunk, G. English, M. J. Fritsch, E. Pourkarimi, and S. J. Coulthurst, J Bacteriol 193:6057-6069, 2011, http://dx.doi.org/10.1128/JB.05671-11). In this study, two new Rhs family antibacterial effectors delivered by this T6SS have been identified. One of these was shown to act as a DNase toxin, while the other contains a novel, cytoplasmic-acting toxin domain. Importantly, using S. marcescens, it has been demonstrated for the first time that Rhs proteins, rather than other T6SS-secreted effectors, can be the primary determinant of intraspecies competition. Furthermore, a new family of accessory proteins associated with T6SS effectors has been identified, exemplified by S. marcescens EagR1, which is specifically required for deployment of its associated Rhs effector. Together, these findings provide new insight into how bacteria can use the T6SS to deploy Rhs-family effectors and mediate different types of interbacterial interactions. Infectious diseases caused by bacterial pathogens represent a continuing threat to health and economic prosperity. To counter this threat, we must understand how such organisms survive and prosper. The type VI secretion system is a weapon that

[Which route leads from chronic back pain to depression? A path analysis on direct and indirect effects using the cognitive mediators catastrophizing and helplessness/hopelessness in a general population sample].

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Fahland, R A; Kohlmann, T; Hasenbring, M; Feng, Y-S; Schmidt, C O

2012-12-01

Chronic pain and depression are highly comorbid; however, the longitudinal link is only partially understood. This study examined direct and indirect effects of chronic back pain on depression using path analysis in a general population sample, focussing on cognitive mediator variables. Analyses are based on 413 participants (aged 18-75 years) in a population-based postal survey on back pain who reported chronic back pain at baseline. Follow-up data were collected after 1 year. Depression was measured with the Center for Epidemiologic Studies Depression Scale (CES-D). Fear-avoidance-beliefs (FABQ), catastrophizing and helplessness/hopelessness (KRSS) were considered as cognitive mediators. Data were analyzed using path analysis. Chronic back pain had no direct effect on depression at follow-up when controlling for cognitive mediators. A mediating effect emerged for helplessness/hopelessness but not for catastrophizing or fear-avoidance beliefs. These results support the cognitive mediation hypothesis which assumes that psychological variables mediate the association between pain and depression. The importance of helplessness/hopelessness is of relevance for the treatment of patients with chronic back pain.

Competitive Think Tanks in Europe

DEFF Research Database (Denmark)

Kelstrup, Jesper Dahl

in opportunity structures that are mediated by historically constituted institutions in knowledge regimes. The paper distinguishes between four different strategies, the authoritative, the collaborative, the agenda-setting and the competitive strategy that are distinguished by the relations think tanks have...

Direct and Indirect Effects of Tofacitinib on Treatment Satisfaction in Patients with Ulcerative Colitis.

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Panés, Julian; Su, Chinyu; Bushmakin, Andrew G; Cappelleri, Joseph C; Healey, Paul

2016-11-01

This mediation modelling analysis evaluated direct and indirect effects of tofacitinib, an oral, small molecule Janus kinase inhibitor under investigation for ulcerative colitis, on patient treatment satisfaction. Data from an 8-week randomized Phase 2 trial [NCT00787202] in adults with moderate-to-severe, active ulcerative colitis receiving twice-daily tofacitinib 0.5-15mg [n=146] or placebo [n=48] were analysed in patient-reported [n=149] and clinician-reported [n=170] outcomes-based mediation models. Binary predictor variable: Treatment [pooled active treatment vs placebo]. Eventual dependent variable: Week 8 patient treatment satisfaction [measured on a five-point Likert scale]. Mediators of treatment effect on satisfaction: Week 8 Inflammatory Bowel Disease Questionnaire domains [Bowel Symptoms, Emotional Health, Social Function and Systemic Symptoms] and Mayo scale domains [Stool Frequency, Rectal Bleeding, Physician's Global Assessment and Endoscopic Disease Activity] for patient-reported and clinician-reported models, respectively. Overall tofacitinib indirect effect on satisfaction via Inflammatory Bowel Disease Questionnaire domains was 40.5% [ptofacitinib effect on satisfaction, 32.4% [p=0.05] was indirectly mediated via Bowel Symptoms; and 30.0% [p=0.04] via Stool Frequency. In total, 59.5% [ptofacitinib's effect on satisfaction was unrelated to Inflammatory Bowel Disease Questionnaire and Mayo scale domains in the patient-reported and clinician-reported models, respectively. Bowel function is an important factor for patient treatment satisfaction with tofacitinib. Treatment effect on patient satisfaction was almost completely mediated via improvement in Mayo scale domains. Copyright © 2016 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

[Effects decomposition in mediation analysis: a numerical example].

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Zugna, Daniela; Richiardi, Lorenzo

2018-01-01

Mediation analysis aims to decompose the total effect of the exposure on the outcome into a direct effect (unmediated) and an indirect effect (mediated by a mediator). When the interest also lies on understanding whether the exposure effect differs in different sub-groups of study population or under different scenarios, the mediation analysis needs to be integrated with interaction analysis. In this setting it is necessary to decompose the total effect not only into two components, the direct and indirect effects, but other two components linked to interaction. The interaction between the exposure and the mediator in their effect on the outcome could indeed act through the effect of the exposure on the mediator or through the mediator when the mediator is not totally explained by the exposure. We describe options for decomposition, proposed in literature, of the total effect and we illustrate them through a hypothetical example of the effect of age at diagnosis of cancer on survival, mediated and unmediated by the therapeutical approach, and a numerical example.

Body-esteem of pupils who attended single-sex versus mixed-sex schools: a cross-sectional study of intrasexual competition and peer victimization.

Science.gov (United States)

Lereya, Suzet Tanya; Eryigit-Madzwamuse, Suna; Patra, Chanchala; Smith, Joshua H; Wolke, Dieter

2014-10-01

In intrasexual competition (competition for reproductive resources), bullying can be viewed as a tool to devalue competitors, gain a high status and a powerful, dominant position in the peer group which may lead to beneficial gains such as access to potential romantic partners. This study investigated the relationship between intrasexual competition, bullying victimization and body-esteem, in single-sex versus mixed-sex schools. 420 participants completed a body-esteem scale, a retrospective bullying questionnaire, and intrasexual competition scales. Our results showed that relational victimization was associated with low body-esteem for both females and males. Females in single-sex schools experienced higher intrasexual competition which in turn was associated with their body-esteem directly and indirectly via relational victimization. In males, intrasexual competition was indirectly associated with body-esteem via relational victimization. Interventions to improve body esteem may focus on reducing intrasexual competition and peer victimization. Copyright © 2014 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Globalization, Tax Competition and Tax Burden İn Turkey

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Veli KARGI

2016-07-01

Full Text Available 1990’s world was quite different from the world of 1950’s. Especially in the last twenty years, the increasing involvement of Japan in the world economy since the 1990s, in addition to the dominance of globalization and market economy throughout the world, the rapid spread of information resulting from the developments in IT-technology and the international competition emerging in the field of technology have all led to some significant developments in the world economy. Reduction of high mobility income and corporate tax rates due to tax competition may cause an unjust distribution of the tax burden. The fact that indirect taxation constitutes about 70% of the tax revenues obtained in Turkey can be taken as an indication of the unfairness in the distribution of tax burden in Turkey. In this study, following a definition of globalization and tax competition, classification of tax competition, reasons for increasing tax competition, benefits and losses of tax competition are explained, and changes introduced by various countries in their tax systems due to tax competition, the distribution of tax burden resulting from tax competition in Turkey and the effectiveness of the new income tax law in Turkey in terms of tax competition are analyzed.

Direct and indirect effects of organizational justice on work ability.

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Spanier, K; Radoschewski, F M; Gutenbrunner, C; Bethge, M

2014-12-01

Organizational justice (OJ), involving transparent workplace procedures and treating staff members with respect, has been of growing concern in recent epidemiological research as a determinant of health-related outcomes. To examine the factorial validity of the German version of Moorman's Organizational Justice Questionnaire (OJQ), to investigate the direct cross-sectional effect of OJ on self-rated work ability and to analyse if there is an additional indirect effect of OJ on work ability mediated by effort-reward imbalance. An analysis of cross-sectional data from the Second German Sociomedical Panel of Employees, involving white-collar workers employed at least half time. We performed confirmatory factor analyses to test the factorial validity of the OJQ and analysed the direct and indirect associations of OJ and self-rated work ability by path model analysis. Of the 1217 participants (47% female; mean age: 51) 36% had poor work ability. Factor analyses confirmed the two-factor structure of the German OJQ. Work ability was explained directly by OJ (β = 0.30) and effort-reward imbalance (β = -0.27). Additionally, we identified an indirect effect of OJ that was mediated by effort-reward imbalance (β = 0.14). The total effect of OJ on work ability was remarkably strong (β = 0.44). Associations remained unchanged after adjustment for socio-demographic parameters. This study showed the importance of considering additional indirect pathways when examining the impact of OJ on the work ability of employees. © The Author 2014. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Decomposition of the Total Effect in the Presence of Multiple Mediators and Interactions.

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Bellavia, Andrea; Valeri, Linda

2018-06-01

Mediation analysis allows decomposing a total effect into a direct effect of the exposure on the outcome and an indirect effect operating through a number of possible hypothesized pathways. Recent studies have provided formal definitions of direct and indirect effects when multiple mediators are of interest and have described parametric and semiparametric methods for their estimation. Investigating direct and indirect effects with multiple mediators, however, can be challenging in the presence of multiple exposure-mediator and mediator-mediator interactions. In this paper we derive a decomposition of the total effect that unifies mediation and interaction when multiple mediators are present. We illustrate the properties of the proposed framework in a secondary analysis of a pragmatic trial for the treatment of schizophrenia. The decomposition is employed to investigate the interplay of side effects and psychiatric symptoms in explaining the effect of antipsychotic medication on quality of life in schizophrenia patients. Our result offers a valuable tool to identify the proportions of total effect due to mediation and interaction when more than one mediator is present, providing the finest decomposition of the total effect that unifies multiple mediators and interactions.

Assessing Natural Direct and Indirect Effects Through Multiple Pathways

DEFF Research Database (Denmark)

Lange, T; Rasmussen, M; Thygesen, Lau Caspar

2014-01-01

. The approach is an extension of the natural effect models proposed by Lange et al. (Am J Epidemiol. 2012;176(3):190-195). By allowing the analysis of distinct multiple pathways, the suggested approach adds to the capabilities of modern mediation techniques. Furthermore, the approach can be implemented using......Within the fields of epidemiology, interventions research and social sciences researchers are often faced with the challenge of decomposing the effect of an exposure into different causal pathways working through defined mediator variables. The goal of such analyses is often to understand...... the mechanisms of the system or to suggest possible interventions. The case of a single mediator, thus implying only 2 causal pathways (direct and indirect) from exposure to outcome, has been extensively studied. By using the framework of counterfactual variables, researchers have established theoretical...

Supporting Risk Assessment: Accounting for Indirect Risk to Ecosystem Components.

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Cathryn Clarke Murray

Full Text Available The multi-scalar complexity of social-ecological systems makes it challenging to quantify impacts from human activities on ecosystems, inspiring risk-based approaches to assessments of potential effects of human activities on valued ecosystem components. Risk assessments do not commonly include the risk from indirect effects as mediated via habitat and prey. In this case study from British Columbia, Canada, we illustrate how such "indirect risks" can be incorporated into risk assessments for seventeen ecosystem components. We ask whether (i the addition of indirect risk changes the at-risk ranking of the seventeen ecosystem components and if (ii risk scores correlate with trophic prey and habitat linkages in the food web. Even with conservative assumptions about the transfer of impacts or risks from prey species and habitats, the addition of indirect risks in the cumulative risk score changes the ranking of priorities for management. In particular, resident orca, Steller sea lion, and Pacific herring all increase in relative risk, more closely aligning these species with their "at-risk status" designations. Risk assessments are not a replacement for impact assessments, but-by considering the potential for indirect risks as we demonstrate here-they offer a crucial complementary perspective for the management of ecosystems and the organisms within.

Supporting Risk Assessment: Accounting for Indirect Risk to Ecosystem Components

Science.gov (United States)

Mach, Megan E.; Martone, Rebecca G.; Singh, Gerald G.; O, Miriam; Chan, Kai M. A.

2016-01-01

The multi-scalar complexity of social-ecological systems makes it challenging to quantify impacts from human activities on ecosystems, inspiring risk-based approaches to assessments of potential effects of human activities on valued ecosystem components. Risk assessments do not commonly include the risk from indirect effects as mediated via habitat and prey. In this case study from British Columbia, Canada, we illustrate how such “indirect risks” can be incorporated into risk assessments for seventeen ecosystem components. We ask whether (i) the addition of indirect risk changes the at-risk ranking of the seventeen ecosystem components and if (ii) risk scores correlate with trophic prey and habitat linkages in the food web. Even with conservative assumptions about the transfer of impacts or risks from prey species and habitats, the addition of indirect risks in the cumulative risk score changes the ranking of priorities for management. In particular, resident orca, Steller sea lion, and Pacific herring all increase in relative risk, more closely aligning these species with their “at-risk status” designations. Risk assessments are not a replacement for impact assessments, but—by considering the potential for indirect risks as we demonstrate here—they offer a crucial complementary perspective for the management of ecosystems and the organisms within. PMID:27632287

Seminal fluid mediates ejaculate competition in social insects

DEFF Research Database (Denmark)

Den Boer, Susanne Petronella A; Baer, Boris; Boomsma, Jacobus Jan

2010-01-01

Queens of ants and bees normally obtain a lifetime supply of sperm on a single day of sexual activity, and sperm competition is expected to occur in lineages where queens receive sperm from multiple males. We compared singly mated (monandrous) and multiply mated (polyandrous) sister groups of ants...

Disturbance-mediated competition between perennial plants along a resource supply gradient

Science.gov (United States)

J. Stephen. Brewer

2011-01-01

Traditional views of ecological disturbance emphasize the role that physical disturbances play in reducing competition between populations and maintaining species coexistence. I present an alternative view that employs a simple Lotka–Volterra model to demonstrate how disturbance resistance, disturbance resilience and resource storage can increase competition between...

Trait-mediated trophic cascade creates enemy-free space for nesting hummingbirds.

Science.gov (United States)

Greeney, Harold F; Meneses, M Rocio; Hamilton, Chris E; Lichter-Marck, Eli; Mannan, R William; Snyder, Noel; Snyder, Helen; Wethington, Susan M; Dyer, Lee A

2015-09-01

The indirect effects of predators on nonadjacent trophic levels, mediated through traits of intervening species, are collectively known as trait-mediated trophic cascades. Although birds are important predators in terrestrial ecosystems, clear examples of trait-mediated indirect effects involving bird predators have almost never been documented. Such indirect effects are important for structuring ecological communities and are likely to be negatively impacted by habitat fragmentation, climate change, and other factors that reduce abundance of top predators. We demonstrate that hummingbirds in Arizona realize increased breeding success when nesting in association with hawks. An enemy-free nesting space is created when jays, an important source of mortality for hummingbird nests, alter their foraging behavior in the presence of their hawk predators.

Changes in direct and indirect taxation in the process of the EU tax system reform

Directory of Open Access Journals (Sweden)

Miletić Vesna

2015-01-01

Full Text Available Proceeding from the changes in direct and indirect taxation in the process of the EU tax system reform and the fact that new trends bring about vital social changes, the research in this area could add to the understanding of economic development of these countries. In the EU with its decentralized tax policy, changes in direct and indirect taxation are permanently implemented in the process of tax system reform. Harmonization of direct and indirect taxation in the EU is conducted by means of the adopted community law regulations. In the harmonization of direct taxation there is a tendency towards an increase of the level of fiscal coordination and elimination of barriers to the common market. Thus direct taxation reforms are limited to achieving higher level of coordination and preventing evasion and double taxation. The current policy is the result of the principle according to which fiscal competition has positive effects on reducing consumption and on the EU economic development. In the harmonization process the systems of indirect taxation are aligned particularly with excise duty and value added tax. Fiscal strategies in the reform process are mostly aimed at fiscal coordination, modernization, informative cooperation, evasion reduction and elimination of malpractices in fulfilling a VAT payment liability. Within the excise tax system minimal excise rates are determined and an environmentally-friendly policy is pursued. The main priorities of taxation changes within the harmonization process are in respect of evasion reduction and irrational fiscal competition on the EU market. A study of direct and indirect taxation changes in the process of the tax system reform is highly significant both from the aspect of efficient tax-system functioning, which results in achieving EU macroeconomic goals, and from the aspect of single states' interests in the process of transition and accession.

Competitive dynamics of energy, environment, and economy in the U.S

International Nuclear Information System (INIS)

Pao, Hsiao-Tien; Chen, Haipeng; Li, Yi-Ying

2015-01-01

This paper applies the Lotka–Volterra model to investigate the competitive interactions among energy, environment, and economy (3Es) in the U.S. The proposed LV-COMSUD (Lotka–Volterra COmpetition Model for SUstainable Development) has satisfactory performance for model fitting and provides a useful multivariate framework to predict outcomes concerning these interactions. Our key findings include a pure competition between emissions and GDP (Gross Domestic Product), neutralisms between renewable and fossil/nuclear energy, and commensalisms between GDP and renewable/fossil energy and between nuclear energy and fossil energy/emissions. These results indicate that renewable/fossil energy use contributes to GDP and interacts indirectly with emissions, that an environmental Kuznets curve exists, and that the amount of produced nuclear energy correlates with emission. The U.S. is dependent on non-clean energy sources and its energy efficiency has room for improvement. The results provide unique insights for policy makers to craft up sustainable economic development plans. Overall, it is suggested that for developed markets such as the U.S., to enhance energy security and mitigate climate changes, improving energy efficiency and developing low-carbon clean energy should be top priorities. - Highlights: • The competitive interactions among energy, environment, and economy are examined. • A pure competition between emissions and GDP exists and an EKC exists. • Energy use contributes to GDP and interacts indirectly with emissions. • Nuclear energy was used to tackle the growth of emissions/fossil energy use. • Improved energy efficiency is a viable policy to enhance energy security in U.S

Causal mediation analysis for longitudinal data with exogenous exposure.

Science.gov (United States)

Bind, M-A C; Vanderweele, T J; Coull, B A; Schwartz, J D

2016-01-01

Mediation analysis is a valuable approach to examine pathways in epidemiological research. Prospective cohort studies are often conducted to study biological mechanisms and often collect longitudinal measurements on each participant. Mediation formulae for longitudinal data have been developed. Here, we formalize the natural direct and indirect effects using a causal framework with potential outcomes that allows for an interaction between the exposure and the mediator. To allow different types of longitudinal measures of the mediator and outcome, we assume two generalized mixed-effects models for both the mediator and the outcome. The model for the mediator has subject-specific random intercepts and random exposure slopes for each cluster, and the outcome model has random intercepts and random slopes for the exposure, the mediator, and their interaction. We also expand our approach to settings with multiple mediators and derive the mediated effects, jointly through all mediators. Our method requires the absence of time-varying confounding with respect to the exposure and the mediator. This assumption is achieved in settings with exogenous exposure and mediator, especially when exposure and mediator are not affected by variables measured at earlier time points. We apply the methodology to data from the Normative Aging Study and estimate the direct and indirect effects, via DNA methylation, of air pollution, and temperature on intercellular adhesion molecule 1 (ICAM-1) protein levels. Our results suggest that air pollution and temperature have a direct effect on ICAM-1 protein levels (i.e. not through a change in ICAM-1 DNA methylation) and that temperature has an indirect effect via a change in ICAM-1 DNA methylation. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Indirect effects of overfishing on Caribbean reefs: sponges overgrow reef-building corals.

Science.gov (United States)

Loh, Tse-Lynn; McMurray, Steven E; Henkel, Timothy P; Vicente, Jan; Pawlik, Joseph R

2015-01-01

Consumer-mediated indirect effects at the community level are difficult to demonstrate empirically. Here, we show an explicit indirect effect of overfishing on competition between sponges and reef-building corals from surveys of 69 sites across the Caribbean. Leveraging the large-scale, long-term removal of sponge predators, we selected overfished sites where intensive methods, primarily fish-trapping, have been employed for decades or more, and compared them to sites in remote or marine protected areas (MPAs) with variable levels of enforcement. Sponge-eating fishes (angelfishes and parrotfishes) were counted at each site, and the benthos surveyed, with coral colonies scored for interaction with sponges. Overfished sites had >3 fold more overgrowth of corals by sponges, and mean coral contact with sponges was 25.6%, compared with 12.0% at less-fished sites. Greater contact with corals by sponges at overfished sites was mostly by sponge species palatable to sponge predators. Palatable species have faster rates of growth or reproduction than defended sponge species, which instead make metabolically expensive chemical defenses. These results validate the top-down conceptual model of sponge community ecology for Caribbean reefs, as well as provide an unambiguous justification for MPAs to protect threatened reef-building corals. An unanticipated outcome of the benthic survey component of this study was that overfished sites had lower mean macroalgal cover (23.1% vs. 38.1% for less-fished sites), a result that is contrary to prevailing assumptions about seaweed control by herbivorous fishes. Because we did not quantify herbivores for this study, we interpret this result with caution, but suggest that additional large-scale studies comparing intensively overfished and MPA sites are warranted to examine the relative impacts of herbivorous fishes and urchins on Caribbean reefs.

Interactions between freshwater snails and tadpoles: competition and facilitation.

Science.gov (United States)

Brönmark, Christer; Rundle, Simon D; Erlandsson, Ann

1991-06-01

Freshwater snails and anuran tadpoles have been suggested to have their highest population densities in ponds of intermediate size where abiotic disturbance (e.g. desiccation) is low and large predators absent. Both snails and tadpoles feed on periphytic algae and, thus, there should be a large potential for competitive interactions to occur between these two distantly related taxa. In a field experiment we examined the relative strength of competition between two closely related snail species, Lymnaea stagnalis and L. peregra, and between L. stagnalis and tadpoles of the common frog, Rana temporaria. Snail growth and egg production and tadpole size at and time to metamorphosis were determined. Effects on the common food source, periphyton, were monitored with the aid of artificial substrates. Periphyton dry weight was dramatically reduced in the presence of snails and/or tadpoles. There were no competitive effects on growth or egg production of the two snail species when they were coexisting. Mortality of L. peregra was high (95%) after reproduction, but independent of treatment. Growth of L. stagnalis was reduced only at the highest tadpole densities, whereas egg production was reduced both by intraspecific competition and by competition with tadpoles. Differences in egg production were retained after tadpole metamorphosis. Tadpole larval period increased, weight of metamorphosing frogs decreased and growth rate was reduced as a function of increasing tadpole density. However, contrary to expectation, snails had a positive effect on tadpole larval period, weight and growth rate. Further, in experimental containers without snails there was a dense growth of the filamentous green alga Cladophora sp. We suggest that the facilitative effects of snails on tadpoles are due to an "indirect mutualistic" mechanism, involving competition between food sources of different quality (microalgae and Cladophora sp.) and tadpoles being competitively dominant over snails for the

Abstract: Inference and Interval Estimation for Indirect Effects With Latent Variable Models.

Science.gov (United States)

Falk, Carl F; Biesanz, Jeremy C

2011-11-30

Models specifying indirect effects (or mediation) and structural equation modeling are both popular in the social sciences. Yet relatively little research has compared methods that test for indirect effects among latent variables and provided precise estimates of the effectiveness of different methods. This simulation study provides an extensive comparison of methods for constructing confidence intervals and for making inferences about indirect effects with latent variables. We compared the percentile (PC) bootstrap, bias-corrected (BC) bootstrap, bias-corrected accelerated (BC a ) bootstrap, likelihood-based confidence intervals (Neale & Miller, 1997), partial posterior predictive (Biesanz, Falk, and Savalei, 2010), and joint significance tests based on Wald tests or likelihood ratio tests. All models included three reflective latent variables representing the independent, dependent, and mediating variables. The design included the following fully crossed conditions: (a) sample size: 100, 200, and 500; (b) number of indicators per latent variable: 3 versus 5; (c) reliability per set of indicators: .7 versus .9; (d) and 16 different path combinations for the indirect effect (α = 0, .14, .39, or .59; and β = 0, .14, .39, or .59). Simulations were performed using a WestGrid cluster of 1680 3.06GHz Intel Xeon processors running R and OpenMx. Results based on 1,000 replications per cell and 2,000 resamples per bootstrap method indicated that the BC and BC a bootstrap methods have inflated Type I error rates. Likelihood-based confidence intervals and the PC bootstrap emerged as methods that adequately control Type I error and have good coverage rates.

Within-Subject Mediation Analysis in AB/BA Crossover Designs.

Science.gov (United States)

Josephy, Haeike; Vansteelandt, Stijn; Vanderhasselt, Marie-Anne; Loeys, Tom

2015-05-01

Crossover trials are widely used to assess the effect of a reversible exposure on an outcome of interest. To gain further insight into the underlying mechanisms of this effect, researchers may be interested in exploring whether or not it runs through a specific intermediate variable: the mediator. Mediation analysis in crossover designs has received scant attention so far and is mostly confined to the traditional Baron and Kenny approach. We aim to tackle mediation analysis within the counterfactual framework and elucidate the assumptions under which the direct and indirect effects can be identified in AB/BA crossover studies. Notably, we show that both effects are identifiable in certain statistical models, even in the presence of unmeasured time-independent (or upper-level) confounding of the mediator-outcome relation. Employing the mediation formula, we derive expressions for the direct and indirect effects in within-subject designs for continuous outcomes that lend themselves to linear modelling, under a large variety of settings. We discuss an estimation approach based on regressing differences in outcomes on differences in mediators and show how to allow for period effects as well as different types of moderation. The performance of this approach is compared to other existing methods through simulations and is illustrated with data from a neurobehavioural study. Lastly, we demonstrate how a sensitivity analysis can be performed that is able to assess the robustness of both the direct and indirect effect against violation of the "no unmeasured lower-level mediator-outcome confounding" assumption.

Field trial of a brucellosis competitive enzyme linked immunoabsorbent assay (ELISA)

International Nuclear Information System (INIS)

Samartino, L.E.; Gregoret, R.J.; Sigal, G.

1998-01-01

The purpose of this study was to evaluate the performance of a competitive ELISA system for the diagnosis of bovine brucellosis in comparison to conventional aerological tests routinely used in Argentina. A total of 2.500 serum samples, comprising Brucella-free herds, vaccinated cattle and naturally infected animals, was tested by the following tests: buffered plate agglutination, Rose Bengal, 2-mercaptoethanol, complement fixation, and indirect and competitive ELISAs. Specificity and relative sensitivity at each test were determined. The competitive ELISA was considered suitable for detection of vaccinated animals and had higher specificity than the other tests. The results point to the potential use of the test as a complementary assay in the brucellosis control programme in Argentina. (author)

Exploring untrained interpreters' use of direct versus indirect speech

DEFF Research Database (Denmark)

Dubslaff, Friedel; Martinsen, Bodil

2005-01-01

by personalizing the indefinite pronoun 'one' when relaying from doctor to patient. All other pronoun shifts occurred in connection with interactional problems caused almost exclusively by the interpreters' lack of knowledge about medical terminology - even though the terms used were in fact non-specialized ones....... The study also indicates that primary parties' shifts from direct to indirect address are closely related either to the form or to the content of the interpreter's prior utterance. Finally, it emerges that repeated one-language talk, triggered by the interpreter's problems with medical terminology, can......This study examines the interrelations between the use of direct vs. indirect speech by primary participants and by dialogue interpreters by focusing on pronoun shifts and their interactional functions. The data consist of four simulated interpreter-mediated medical interviews based on the same...

mma: An R Package for Mediation Analysis with Multiple Mediators

Directory of Open Access Journals (Sweden)

Qingzhao Yu

2017-04-01

Full Text Available Mediation refers to the effect transmitted by mediators that intervene in the relationship between an exposure and a response variable. Mediation analysis has been broadly studied in many fields. However, it remains a challenge for researchers to consider complicated associations among variables and to differentiate individual effects from multiple mediators. [1] proposed general definitions of mediation effects that were adaptable to all different types of response (categorical or continuous, exposure, or mediation variables. With these definitions, multiple mediators of different types can be considered simultaneously, and the indirect effects carried by individual mediators can be separated from the total effect. Moreover, the derived mediation analysis can be performed with general predictive models. That is, the relationships among variables can be modeled using not only generalized linear models but also nonparametric models such as the Multiple Additive Regression Trees. Therefore, more complicated variable transformations and interactions can be considered in analyzing the mediation effects. The proposed method is realized by the R package 'mma'. We illustrate in this paper the proposed method and how to use 'mma' to estimate mediation effects and make inferences.

Migratory herds of wildebeests and zebras indirectly affect calf survival of giraffes.

Science.gov (United States)

Lee, Derek E; Kissui, Bernard M; Kiwango, Yustina A; Bond, Monica L

2016-12-01

In long-distance migratory systems, local fluctuations in the predator-prey ratio can exhibit extreme variability within a single year depending upon the seasonal location of migratory species. Such systems offer an opportunity to empirically investigate cyclic population density effects on short-term food web interactions by taking advantage of the large seasonal shifts in migratory prey biomass.We utilized a large-mammal predator-prey savanna food web to evaluate support for hypotheses relating to the indirect effects of "apparent competition" and "apparent mutualism" from migratory ungulate herds on survival of resident megaherbivore calves, mediated by their shared predator. African lions ( Panthera leo ) are generalist predators whose primary, preferred prey are wildebeests ( Connochaetes taurinus ) and zebras ( Equus quagga ), while lion predation on secondary prey such as giraffes ( Giraffa camelopardalis ) may change according to the relative abundance of the primary prey species.We used demographic data from five subpopulations of giraffes in the Tarangire Ecosystem of Tanzania, East Africa, to test hypotheses relating to direct predation and indirect effects of large migratory herds on calf survival of a resident megaherbivore. We examined neonatal survival via apparent reproduction of 860 adult females, and calf survival of 449 giraffe calves, during three precipitation seasons over 3 years, seeking evidence of some effect on neonate and calf survival as a consequence of the movements of large herds of migratory ungulates.We found that local lion predation pressure (lion density divided by primary prey density) was significantly negatively correlated with giraffe neonatal and calf survival probabilities. This supports the apparent mutualism hypothesis that the presence of migratory ungulates reduces lion predation on giraffe calves.Natural predation had a significant effect on giraffe calf and neonate survival, and could significantly affect giraffe

Two-step estimation in ratio-of-mediator-probability weighted causal mediation analysis.

Science.gov (United States)

Bein, Edward; Deutsch, Jonah; Hong, Guanglei; Porter, Kristin E; Qin, Xu; Yang, Cheng

2018-04-15

This study investigates appropriate estimation of estimator variability in the context of causal mediation analysis that employs propensity score-based weighting. Such an analysis decomposes the total effect of a treatment on the outcome into an indirect effect transmitted through a focal mediator and a direct effect bypassing the mediator. Ratio-of-mediator-probability weighting estimates these causal effects by adjusting for the confounding impact of a large number of pretreatment covariates through propensity score-based weighting. In step 1, a propensity score model is estimated. In step 2, the causal effects of interest are estimated using weights derived from the prior step's regression coefficient estimates. Statistical inferences obtained from this 2-step estimation procedure are potentially problematic if the estimated standard errors of the causal effect estimates do not reflect the sampling uncertainty in the estimation of the weights. This study extends to ratio-of-mediator-probability weighting analysis a solution to the 2-step estimation problem by stacking the score functions from both steps. We derive the asymptotic variance-covariance matrix for the indirect effect and direct effect 2-step estimators, provide simulation results, and illustrate with an application study. Our simulation results indicate that the sampling uncertainty in the estimated weights should not be ignored. The standard error estimation using the stacking procedure offers a viable alternative to bootstrap standard error estimation. We discuss broad implications of this approach for causal analysis involving propensity score-based weighting. Copyright © 2018 John Wiley & Sons, Ltd.

Growth performance and carcass traits in pigs selected for indirect genetic effects on growth rate in two environments

NARCIS (Netherlands)

Camerlink, I.; Bolhuis, J.E.; Duijvesteijn, N.; Arendonk, van J.A.M.; Bijma, P.

2014-01-01

Production traits such as growth rate may depend on the social interactions between group members. These social interactions might be partly heritable and are referred to as indirect genetic effects (IGE), social-, associative-, or competitive genetic effects. IGE may contribute to heritable

Mediation misgivings: ambiguous clinical and public health interpretations of natural direct and indirect effects.

Science.gov (United States)

Naimi, Ashley I; Kaufman, Jay S; MacLehose, Richard F

2014-10-01

Recent methodological innovation is giving rise to an increasing number of applied papers in medical and epidemiological journals in which natural direct and indirect effects are estimated. However, there is a longstanding debate on whether such effects are relevant targets of inference in population health. In light of the repeated calls for a more pragmatic and consequential epidemiology, we review three issues often raised in this debate: (i) the use of composite cross-world counterfactuals and the need for cross-world independence assumptions; (ii) interventional vs non-interventional identifiability; and (iii) the interpretational ambiguity of natural direct and indirect effect estimates. We use potential outcomes notation and directed acyclic graphs to explain 'cross-world' assumptions, illustrate implications of this assumption via regression models and discuss ensuing issues of interpretation. We argue that the debate on the relevance of natural direct and indirect effects rests on whether one takes as a target of inference the mathematical object per se, or the change in the world that the mathematical object represents. We further note that public health questions may be better served by estimating controlled direct effects. © The Author 2014; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

The multitalented Mediator complex.

Science.gov (United States)

Carlsten, Jonas O P; Zhu, Xuefeng; Gustafsson, Claes M

2013-11-01

The Mediator complex is needed for regulated transcription of RNA polymerase II (Pol II)-dependent genes. Initially, Mediator was only seen as a protein bridge that conveyed regulatory information from enhancers to the promoter. Later studies have added many other functions to the Mediator repertoire. Indeed, recent findings show that Mediator influences nearly all stages of transcription and coordinates these events with concomitant changes in chromatin organization. We review the multitude of activities associated with Mediator and discuss how this complex coordinates transcription with other cellular events. We also discuss the inherent difficulties associated with in vivo characterization of a coactivator complex that can indirectly affect diverse cellular processes via changes in gene transcription. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect decomposition in the presence of an exposure-induced mediator-outcome confounder

Science.gov (United States)

VanderWeele, Tyler J.; Vansteelandt, Stijn; Robins, James M.

2014-01-01

Methods from causal mediation analysis have generalized the traditional approach to direct and indirect effects in the epidemiologic and social science literature by allowing for interaction and non-linearities. However, the methods from the causal inference literature have themselves been subject to a major limitation in that the so-called natural direct and indirect effects that are employed are not identified from data whenever there is a variable that is affected by the exposure, which also confounds the relationship between the mediator and the outcome. In this paper we describe three alternative approaches to effect decomposition that give quantities that can be interpreted as direct and indirect effects, and that can be identified from data even in the presence of an exposure-induced mediator-outcome confounder. We describe a simple weighting-based estimation method for each of these three approaches, illustrated with data from perinatal epidemiology. The methods described here can shed insight into pathways and questions of mediation even when an exposure-induced mediator-outcome confounder is present. PMID:24487213

Competitive interactions are mediated in a sex-specific manner by arbuscular mycorrhiza in Antennaria dioica.

Science.gov (United States)

Varga, S; Vega-Frutis, R; Kytöviita, M-M

2017-03-01

Plants usually interact with other plants, and the outcome of such interaction ranges from facilitation to competition depending on the identity of the plants, including their sexual expression. Arbuscular mycorrhizal (AM) fungi have been shown to modify competitive interactions in plants. However, few studies have evaluated how AM fungi influence plant intraspecific and interspecific interactions in dioecious species. The competitive abilities of female and male plants of Antennaria dioica were examined in a greenhouse experiment. Females and males were grown in the following competitive settings: (i) without competition, (ii) with intrasexual competition, (iii) with intersexual competition, and (iv) with interspecific competition by Hieracium pilosella - a plant with similar characteristics to A. dioica. Half of the pots were grown with Claroideoglomus claroideum, an AM fungus isolated from the same habitat as the plant material. We evaluated plant survival, growth, flowering phenology, and production of AM fungal structures. Plant survival was unaffected by competition or AM fungi. Competition and the presence of AM fungi reduced plant biomass. However, the sexes responded differently to the interaction between fungal and competition treatments. Both intra- and interspecific competition results were sex-specific, and in general, female performance was reduced by AM colonization. Plant competition or sex did not affect the intraradical structures, extraradical hyphae, or spore production of the AM fungus. These findings suggest that plant sexual differences affect fundamental processes such as competitive ability and symbiotic relationships with AM fungi. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Pyrrhic Victories: The Need for Social Status Drives Costly Competitive Behavior.

Directory of Open Access Journals (Sweden)

Wouter eVan Den Bos

2013-10-01

Full Text Available Competitive behavior is commonly defined as the decision to maximize one’s payoffs relative to others. We argue instead that competitive drive derives from a desire for social status. We make use of a multi-player auction task in which subjects knowingly incur financial losses for the sake of winning auctions. First, we show that overbidding is increased when the task includes members of a rival out-group, suggesting that social identity is an important mediator of competitiveness. In addition, we show that the extent that individuals are willing to incur losses is related to affective responses to social comparisons but not to monetary outcomes. Second, we show that basal levels of testosterone predict overbidding, and that this effect of testosterone is mediated by affective responses to social comparisons. Based on these findings, we argue that competitive behavior should be conceptualized in terms of social motivations as opposed to just relative monetary payoffs.

Host plant quality mediates competition between arbuscular mycorrhizal fungi

Czech Academy of Sciences Publication Activity Database

Knegt, B.; Jansa, Jan; Franken, O.; Engelmoer, D.J.P.; Werner, G.D.A.; Bucking, H.; Kiers, E. T.

2016-01-01

Roč. 20, April (2016), s. 233-240 ISSN 1754-5048 R&D Projects: GA MŠk(CZ) LK11224 Institutional support: RVO:61388971 Keywords : Biological market * Competitive exclusion * Cooperation Mutualism Subject RIV: EE - Microbiology, Virology Impact factor: 3.219, year: 2016

Practical Guidance for Conducting Mediation Analysis With Multiple Mediators Using Inverse Odds Ratio Weighting

OpenAIRE

Nguyen, Quynh C.; Osypuk, Theresa L.; Schmidt, Nicole M.; Glymour, M. Maria; Tchetgen Tchetgen, Eric J.

2015-01-01

Despite the recent flourishing of mediation analysis techniques, many modern approaches are difficult to implement or applicable to only a restricted range of regression models. This report provides practical guidance for implementing a new technique utilizing inverse odds ratio weighting (IORW) to estimate natural direct and indirect effects for mediation analyses. IORW takes advantage of the odds ratio's invariance property and condenses information on the odds ratio for the relationship be...

General theory of excitation energy transfer in donor-mediator-acceptor systems.

Science.gov (United States)

Kimura, Akihiro

2009-04-21

General theory of the excitation energy transfer (EET) in the case of donor-mediator-acceptor system was constructed by using generalized master equation (GME). In this theory, we consider the direct and indirect transitions in the EET consistently. Hence, our theory includes the quantum mechanical interference between the direct and indirect transitions automatically. Memory functions in the GME were expressed by the overlap integrals among the time-dependent emission spectrum of the donor, the absorption spectrum of the mediator, the time-dependent emission spectrum of the mediator, and the absorption spectrum of the acceptor. In the Markov limit of the memory functions, we obtained the rate of EET which consists of three terms due to the direct transition, the indirect transition, and the interference between them. We found that the interference works effectively in the limit of slow thermalization at the intermediate state. The formula of EET rate in this limit was expressed by the convolution of the EET interaction and optical spectra. The interference effect strongly depends on the width of the absorption spectrum of mediator molecule and the energy gap between the donor and the mediator molecules.

Plant-plant competition outcomes are modulated by plant effects on the soil bacterial community.

Science.gov (United States)

Hortal, S; Lozano, Y M; Bastida, F; Armas, C; Moreno, J L; Garcia, C; Pugnaire, F I

2017-12-19

Competition is a key process that determines plant community structure and dynamics, often mediated by nutrients and water availability. However, the role of soil microorganisms on plant competition, and the links between above- and belowground processes, are not well understood. Here we show that the effects of interspecific plant competition on plant performance are mediated by feedbacks between plants and soil bacterial communities. Each plant species selects a singular community of soil microorganisms in its rhizosphere with a specific species composition, abundance and activity. When two plant species interact, the resulting soil bacterial community matches that of the most competitive plant species, suggesting strong competitive interactions between soil bacterial communities as well. We propose a novel mechanism by which changes in belowground bacterial communities promoted by the most competitive plant species influence plant performance and competition outcome. These findings emphasise the strong links between plant and soil communities, paving the way to a better understanding of plant community dynamics and the effects of soil bacterial communities on ecosystem functioning and services.

Effect Size Measures for Mediation Models: Quantitative Strategies for Communicating Indirect Effects

Science.gov (United States)

Preacher, Kristopher J.; Kelley, Ken

2011-01-01

The statistical analysis of mediation effects has become an indispensable tool for helping scientists investigate processes thought to be causal. Yet, in spite of many recent advances in the estimation and testing of mediation effects, little attention has been given to methods for communicating effect size and the practical importance of those…

Resource competition in plant invasions: emerging patterns and research needs.

Science.gov (United States)

Gioria, Margherita; Osborne, Bruce A

2014-01-01

Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, although invasive congeners are not necessarily competitively superior over native congeners, nor are alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy). Finally, we identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examination of resource competition dynamics and the impact of global environmental change on competitive interactions between invasive and native species.

Resource competition in plant invasions: emerging patterns and research needs

Science.gov (United States)

Gioria, Margherita; Osborne, Bruce A.

2014-01-01

Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, although invasive congeners are not necessarily competitively superior over native congeners, nor are alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy). Finally, we identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examination of resource competition dynamics and the impact of global environmental change on competitive interactions between invasive and native species. PMID

Comparative evaluation of competitive ELISA test in Colombian cattle

International Nuclear Information System (INIS)

Marino, O.; Rueda, E.; Sedano, L.; Zuniga, I.; Calderon, C.; Ortega, A.; Puentes, A.

1998-01-01

In order to contribute to the definition of the best ELISA test for screening and differential diagnosis of Brucella abortus to be applied for control programmes, a total of 2971 sera from Colombian cattle were tested for brucellosis. Conventional agglutination tests, Buffered Plate antigen test (BPAT) and Rose Bengal (RB) as well as Complement Fixation test (CFT) (Alton, et al. 1988) were used comparatively. Radial immunodiffusion test (RID) was also performed to all sera. The sera were also tested using four different ELISAs: indirect ELISA from FAO/IAEA and the indirect ELISA modified by Nielsen, et al. 1992 as well as two competitive ELISAs: one competitive ELISA used B. abortus O-polysaccharide antigen and an enzyme conjugated monoclonal to the O-polysaccharide for competition and detection. The second competitive ELISA used lipopolysaccharide (sLPS) antigen, a different monoclonal antibody for competition but also specific for the O-polysaccharide and a commercially available goat anti-mouse IgG enzyme conjugate for detection. The sera were analyzed based on its population status, 987 positive obtained from Brucella abortus infected herds based on clinical and/or bacteriological evidence and a high prevalence of brucellosis, CFT percentage of positive animals in the herd was greater than 5%. Eight hundred sixty six (866) negative sera from non-vaccinated cattle from a brucellosis free area and 1118 negative sera obtained from reglamentary vaccinated areas under a free herd program. Initial cut-off values were derived using negative serum samples. The diagnostic sensitivity and specificity was defined from frequency histograms based on this cut-off values and using 2x2 tables, corresponding confidence limits (95%) were calculated. The data were also analysed using signal detection analysis (ROC). Kappa statistics was determined for all tests and populations, accuracy was used as index of comparison to evaluate different assays. The data support the initial

Socio-hydrologic modeling to understand and mediate the competition for water between agriculture development and environmental health: Murrumbidgee River basin, Australia

Science.gov (United States)

van Emmerik, T. H. M.; Li, Z.; Sivapalan, M.; Pande, S.; Kandasamy, J.; Savenije, H. H. G.; Chanan, A.; Vigneswaran, S.

2014-10-01

Competition for water between humans and ecosystems is set to become a flash point in the coming decades in many parts of the world. An entirely new and comprehensive quantitative framework is needed to establish a holistic understanding of that competition, thereby enabling the development of effective mediation strategies. This paper presents a modeling study centered on the Murrumbidgee River basin (MRB). The MRB has witnessed a unique system dynamics over the last 100 years as a result of interactions between patterns of water management and climate driven hydrological variability. Data analysis has revealed a pendulum swing between agricultural development and restoration of environmental health and ecosystem services over different stages of basin-scale water resource development. A parsimonious, stylized, quasi-distributed coupled socio-hydrologic system model that simulates the two-way coupling between human and hydrological systems of the MRB is used to mimic and explain dominant features of the pendulum swing. The model consists of coupled nonlinear ordinary differential equations that describe the interaction between five state variables that govern the co-evolution: reservoir storage, irrigated area, human population, ecosystem health, and environmental awareness. The model simulations track the propagation of the external climatic and socio-economic drivers through this coupled, complex system to the emergence of the pendulum swing. The model results point to a competition between human "productive" and environmental "restorative" forces that underpin the pendulum swing. Both the forces are endogenous, i.e., generated by the system dynamics in response to external drivers and mediated by humans through technology change and environmental awareness, respectively. Sensitivity analysis carried out with the model further reveals that socio-hydrologic modeling can be used as a tool to explain or gain insight into observed co-evolutionary dynamics of diverse

Effects of informal competition on innovation performance: the case of pacific alliance

Directory of Open Access Journals (Sweden)

Jorge Heredia

2017-12-01

Full Text Available This study evaluates the impact of informal competition on the innovation performance of formal firms in emerging economies. A theoretical model under the strategy tripod framework is proposed. It analyzes the effects of Institutional factors as the quality of governance and market labor rigidities on innovation performance, and the mediating effect of informal competition. It is used the Causal Mediation Analysis with data from 3,268 companies from the World Bank Enterprise Survey from countries of the Pacific Alliance (Chile, Colombia, Mexico, and Peru. The results state that informal competition has a negative effect on the innovation performance of formal companies. Based on these findings, It is suggested some promising avenues for future research and managerial implications.

Changes in the North Sea fish community: evidence of indirect effects of fishing?

NARCIS (Netherlands)

Daan, N.; Gislason, H.; Pope, J.G.; Rice, J.C.

2005-01-01

We investigate changes in the North Sea fish community with particular reference to possible indirect effects of fishing, mediated through the ecosystem. In the past, long-term changes in the slope of size spectra of research vessel catches have been related to changes in fishing effort, but such

MP-4 Contributes to Snake Venom Neutralization by Mucuna pruriens Seeds through an Indirect Antibody-mediated Mechanism*

Science.gov (United States)

Kumar, Ashish; Gupta, Chitra; Salunke, Dinakar M.

2016-01-01

Mortality due to snakebite is a serious public health problem, and available therapeutics are known to induce debilitating side effects. Traditional medicine suggests that seeds of Mucuna pruriens can provide protection against the effects of snakebite. Our aim is to identify the protein(s) that may be important for snake venom neutralization and elucidate its mechanism of action. To this end, we have identified and purified a protein from M. pruriens, which we have named MP-4. The full-length polypeptide sequence of MP-4 was obtained through N-terminal sequencing of peptide fragments. Sequence analysis suggested that the protein may belong to the Kunitz-type protease inhibitor family and therefore may potentially neutralize the proteases present in snake venom. Using various structural and biochemical tools coupled with in vivo assays, we are able to show that MP-4 does not afford direct protection against snake venom because it is actually a poor inhibitor of serine proteases. Further experiments showed that antibodies generated against MP-4 cross-react with the whole venom and provide protection to mice against Echis carinatus snake venom. This study shows that the MP-4 contributes significantly to the snake venom neutralization activity of M. pruriens seeds through an indirect antibody-mediated mechanism. PMID:26987900

Monetary and fiscal policy aspects of indirect tax changes in a monetary union

OpenAIRE

von Thadden, Leopold; Lipińska, Anna

2009-01-01

In recent years a number of European countries have shifted their tax structure more strongly towards indirect taxes, motivated, inter alia, by the intention to foster competitiveness. Against this background, this paper develops a tractable two-country model of a monetary union, characterised by national fiscal and supranational monetary policy, with price-setting firms and endogenously determined terms of trade. The paper discusses a number of monetary and fiscal policy questions which emer...

A Plant-Feeding Nematode Indirectly Increases the Fitness of an Aphid

Directory of Open Access Journals (Sweden)

Grace A. Hoysted

2017-11-01

Full Text Available Plants suffer multiple, simultaneous assaults from above and below ground. In the laboratory, pests and/or pathogen attack are commonly studied on an individual basis. The molecular response of the plant to attack from multiple organisms and the interaction of different defense pathways is unclear. The inducible systemic responses of the potato (Solanum tuberosum L. host plant were analyzed to characterize the plant-mediated indirect interactions between a sedentary, endoparasitic nematode (Globodera pallida, and a phloem-sucking herbivore (Myzus persicae. The reproductive success of M. persicae was greater on potato plants pre-infected with G. pallida compared to control plants. Salicylic acid (SA increased systemically in the leaves of potato plants following nematode and aphid infection singly with a corresponding increase in expression of SA-mediated marker genes. An increase in jasmonic acid associated with aphid infection was suppressed when plants were co-infected with nematodes. Our data suggests a positive, asymmetric interaction between a sedentary endoparasitic nematode and a sap-sucking insect. The systemic response of the potato plant following infection with G. pallida indirectly influences the performance of M. persicae. This work reveals additional secondary benefits of controlling individual crop pests.

Specificity in mediated pathways by anxiety symptoms linking adolescent stress profiles to depressive symptoms: Results of a moderated mediation approach.

Science.gov (United States)

Anyan, Frederick; Bizumic, Boris; Hjemdal, Odin

2018-03-01

We investigated the specificity in mediated pathways that separately link specific stress dimensions through anxiety to depressive symptoms and the protective utility of resilience. Thus, this study goes beyond lumping together potential mediating and moderating processes that can explain the relations between stress and (symptoms of) psychopathology and the buffering effect of resilience. Ghanaian adolescents between 13 and 17 years (female = 285; male = 244) completed the Adolescent Stress Questionnaire (ASQ), Spielberger State Anxiety Inventory (STAI), Short Mood Feeling Questionnaire (SMFQ) and the Resilience Scale for Adolescents (READ). Independent samples t-test, multivariate analysis of covariance with follow-up tests and moderated mediation analyses were performed. Evidences were found for specificity in the associations between dimensions of adolescent stressors and depressive symptoms independent of transient anxiety. Transient anxiety partly accounted for the indirect effects of eight stress dimensions on depressive symptoms. Except stress of school attendance and school/leisure conflict, resilience moderated the indirect effects of specific stress dimensions on depressive symptoms. Results suggested differences in how Ghanaian adolescents view the various stress dimensions, and mediated pathways associated with anxiety and depressive symptoms. Use of cross-sectional data does not show causal process and temporal changes over time. Findings support and clarify the specificity in the interrelations and mediated pathways among dimensions of adolescent stress, transient anxiety, and depressive symptoms. Conditional process analyses shows that resilience does not only buffer direct, but also indirect psychological adversities. Interventions for good mental health may focus on low resilience subgroups in specific stress dimensions while minimizing transient anxiety. Copyright © 2017 Elsevier B.V. All rights reserved.

Direct and Indirect Effects of Parenting and Children's Goals on Child Aggression

Science.gov (United States)

Heidgerken, Amanda D.; Hughes, Jan N.; Cavell, Timothy A.; Willson, Victor L.

2004-01-01

This study tested a dual-mediation model of the relations among harsh parenting, hostile social information processing, and level of child aggression in a sample of 239 (150 male, 89 female) 2nd- to 4th-grade children. The theoretical model posited that harsh parenting has both direct and indirect effects on child level of aggression, with the…

Exploring the Relationship Between Social Anxiety and Bulimic Symptoms: Mediational Effects of Perfectionism Among Females

Science.gov (United States)

Menatti, Andrew R.; Weeks, Justin W.; Levinson, Cheri A.; McGowan, Maggie M.

2013-01-01

Previous findings indicate that social anxiety and bulimia co-occur at high rates; one mechanism that has been proposed to link these symptom clusters is perfectionism. We tested meditational models among 167 female undergraduates in which maladaptive evaluative perfectionism concerns (MEPC; i.e., critical self-evaluative perfectionism) mediated the relationship between social anxiety and bulimic symptoms. Results from a first model indicated that MEPC mediated the relationship between fear of public scrutiny and bulimia symptoms. This indirect effect was significant above and beyond the indirect effects of maladaptive body-image cognitions and perfectionism specific to pure personal standards. A second model was tested with MEPC mediating the relationship between social interaction anxiety and bulimia symptoms. Similar results were obtained; however, in this model, a significant direct effect remained after partialing out the indirect effect of the mediators. Theoretical implications are discussed. PMID:24932054

Competition triggers plasmid-mediated enhancement of substrate utilisation in Pseudomonas putida.

Directory of Open Access Journals (Sweden)

Hiren Joshi

2009-06-01

Full Text Available Competition between species plays a central role in the activity and structure of communities. Stable co-existence of diverse organisms in communities is thought to be fostered by individual tradeoffs and optimization of competitive strategies along resource gradients. Outside the laboratory, microbes exist as multispecies consortia, continuously interacting with one another and the environment. Survival and proliferation of a particular species is governed by its competitive fitness. Therefore, bacteria must be able to continuously sense their immediate environs for presence of competitors and prevailing conditions. Here we present results of our investigations on a novel competition sensing mechanism in the rhizosphere-inhabiting Pseudomonas putida KT2440, harbouring gfpmut3b-modified Kan(R TOL plasmid. We monitored benzyl alcohol (BA degradation rate, along with GFP expression profiling in mono species and dual species cultures. Interestingly, enhanced plasmid expression (monitored using GFP expression and consequent BA degradation were observed in dual species consortia, irrespective of whether the competitor was a BA degrader (Pseudomonas aeruginosa or a non-degrader (E. coli. Attempts at elucidation of the mechanistic aspects of induction indicated the role of physical interaction, but not of any diffusible compounds emanating from the competitors. This contention is supported by the observation that greater induction took place in presence of increasing number of competitors. Inert microspheres mimicking competitor cell size and concentration did not elicit any significant induction, further suggesting the role of physical cell-cell interaction. Furthermore, it was also established that cell wall compromised competitor had minimal induction capability. We conclude that P. putida harbouring pWW0 experience a competitive stress when grown as dual-species consortium, irrespective of the counterpart being BA degrader or not. The immediate

Organizational Culture, Absorptive Capacity, Innovation Performace and Competitive Advantage: An Integrated Assessment in Indonesian Banking Industry

Directory of Open Access Journals (Sweden)

Ahmad Adriansyah

2015-06-01

Full Text Available The positive impact of absorptive capacity (ACAP on innovation and the positive impact of innovation on competitive advantage have been proven in different research contexts. However, current knowledge on organizational culture that affects ACAP, innovation and competitive advantage as a whole, remains unclear. This article proposes a model to examine how organizational culture (developmental culture and rational culture affects ACAP, innovation and competitive advantage, directly and indirectly as well.  Surveyed data (in Indonesian Banking Industry shows that both of organizational culture have a direct impact on ACAP. Only developmental culture has a direct impact on innovation. There is no culture type affects competitive advantage directly. In this research, culture affects competitive advantage through ACAP and innovation.    

Direct and indirect effects of alcohol expectancies through drinking motives on alcohol outcomes among students in Vietnam.

Science.gov (United States)

Diep, Pham Bich; Schelleman-Offermans, K; Kuntsche, E; De Vries, Nanne; Knibbe, Ronald A

2016-01-01

To investigate whether the links between alcohol expectancies (tension reduction; global positive change; improved cognitive and motor abilities; and change in social behavior) and alcohol outcomes (drinking volume, 6+ drinks, alcohol problems, and symptoms of alcohol dependence) are mediated by drinking motives (social, enhancement, conformity, and coping). A multi-stage sampling strategy was used in four Vietnamese provinces, resulting in a final sample of 4756 students (43.2% females) with mean age 20.6 (SD 1.8) years. Structural equation models, including indirect effects, were estimated for women and men separately. Overall, there were many cases of full mediation (indirect effects range from -0.006 to 0.083 and p-values from alcohol outcomes. Among men, enhancement motives and, to a lesser extent, social motives also played a role in mediating the effects of expectancies on alcohol outcomes. Among women, full mediation was found far less often and less consistently. By confirming that, in Vietnam, motives mediate the link between expectancies and drinking behavior, this study supports the cultural robustness of a key assumption of the motivational model (i.e. that drinking motives are more closely associated with alcohol use than expectancies). Enhancement, coping and social motives are most frequently found as mediators among male students whereas coping motive only is most frequently found as a mediator among female students. As most of the effects of expectancies were mediated by motives, drinking motives appear to be a promising factor for interventions. Copyright © 2015 Elsevier Ltd. All rights reserved.

On the Interpretation and Use of Mediation: Multiple Perspectives on Mediation Analysis

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Agler, Robert; De Boeck, Paul

2017-01-01

Mediation analysis has become a very popular approach in psychology, and it is one that is associated with multiple perspectives that are often at odds, often implicitly. Explicitly discussing these perspectives and their motivations, advantages, and disadvantages can help to provide clarity to conversations and research regarding the use and refinement of mediation models. We discuss five such pairs of perspectives on mediation analysis, their associated advantages and disadvantages, and their implications: with vs. without a mediation hypothesis, specific effects vs. a global model, directness vs. indirectness of causation, effect size vs. null hypothesis testing, and hypothesized vs. alternative explanations. Discussion of the perspectives is facilitated by a small simulation study. Some philosophical and linguistic considerations are briefly discussed, as well as some other perspectives we do not develop here. PMID:29187828

On the Interpretation and Use of Mediation: Multiple Perspectives on Mediation Analysis.

Science.gov (United States)

Agler, Robert; De Boeck, Paul

2017-01-01

Mediation analysis has become a very popular approach in psychology, and it is one that is associated with multiple perspectives that are often at odds, often implicitly. Explicitly discussing these perspectives and their motivations, advantages, and disadvantages can help to provide clarity to conversations and research regarding the use and refinement of mediation models. We discuss five such pairs of perspectives on mediation analysis, their associated advantages and disadvantages, and their implications: with vs. without a mediation hypothesis, specific effects vs. a global model, directness vs. indirectness of causation, effect size vs. null hypothesis testing, and hypothesized vs. alternative explanations. Discussion of the perspectives is facilitated by a small simulation study. Some philosophical and linguistic considerations are briefly discussed, as well as some other perspectives we do not develop here.

Competition as a mechanism structuring mutualisms

Science.gov (United States)

Robert J. Warren; Itamar Giladi; Mark A. Bradford

2014-01-01

Summary 1. Hutchinsonian niche theory posits that organisms have fundamental abiotic resource requirements from which they are limited by competition. Organisms also have fundamental biotic requirements, such as mutualists, for which they also might compete. 2. We test this idea with a widespread ant–plant mutualism. Ant-mediated seed dispersal (myrmecochory) in...

Infectious diseases in competitive sports.

Science.gov (United States)

Goodman, R A; Thacker, S B; Solomon, S L; Osterholm, M T; Hughes, J M

1994-03-16

Participation in competitive sports is popular and widely encouraged throughout the United States. Reports of infectious disease outbreaks among competitive athletes and recent publicity regarding infectious disease concerns in sports underscore the need to better characterize the occurrence of these problems. To identify reports of infectious diseases in sports, we performed a comprehensive search of the medical literature (MEDLINE) and newspaper databases in two on-line services (NEXIS and DIALOG PAPERS). Articles selected from the literature review included those describing cases or outbreaks of disease in which exposure to an infectious agent was likely to have occurred during training for competitive sports or during actual competition. Articles from the newspaper review included reports of outbreaks, exposures, or preventive measures that directly or indirectly involved teams or spectators. The literature review identified 38 reports of infectious disease outbreaks or other instances of transmission through person-to-person (24 reports), common-source (nine reports), or airborne (five reports) routes; the newspaper search identified 28 reports. Infectious agents included predominantly viruses but also a variety of fungi and gram-positive and gram-negative bacteria. Our findings indicate that strategies to prevent transmission of infectious diseases in sports must recognize risks at three levels: the individual athlete, the team, and spectators or others who may become exposed to infectious diseases as a result of sports-related activities. Team physicians and others who are responsible for the health of athletes should be especially familiar with the features of infectious diseases that occur in sports and measures for the prevention of these problems.

Does adiposity mediate the relationship between physical activity and biological risk factors in youth?

DEFF Research Database (Denmark)

Tarp, J; Bugge, A; Andersen, L B

2018-01-01

BACKGROUND/OBJECTIVES: To model the association between accumulating 60 daily minutes of moderate-to-vigorous physical activity and a composite score of biological risk factors into a direct and an indirect effect, using abdominal obesity as the mediator. SUBJECTS/METHODS: Cross-sectional data from.......11, -0.02) to the indirect effect indicating that 22% of the total effect was mediated by central adiposity. Modelling 30 and 90 min of moderate-to-vigorous physical activity per day resulted in changes in the direct but not the indirect effect. CONCLUSIONS: One hour of daily moderate...... of insulin, glucose, triacylglycerol and inverse HDL-cholesterol. Abdominal obesity was assessed by the waist-circumference:height ratio. Two-stage regression analysis, allowing for exposure-mediator interaction, was used for the effect decomposition. RESULTS: Participants achieving 60 daily minutes...

Causal mediation analysis with a binary outcome and multiple continuous or ordinal mediators: Simulations and application to an alcohol intervention

OpenAIRE

Nguyen, Trang Quynh; Webb-Vargas, Yenny; Koning, Ina M.; Stuart, Elizabeth A.

2016-01-01

We investigate a method to estimate the combined effect of multiple continuous/ordinal mediators on a binary outcome: 1) fit a structural equation model with probit link for the outcome and identity/probit link for continuous/ordinal mediators, 2) predict potential outcome probabilities, and 3) compute natural direct and indirect effects. Step 2 involves rescaling the latent continuous variable underlying the outcome to address residual mediator variance/covariance. We evaluate the estimation...

Indirect presentation in the thymus limits naive and regulatory T-cell differentiation by promoting deletion of self-reactive thymocytes.

Science.gov (United States)

Yap, Jin Yan; Wirasinha, Rushika C; Chan, Anna; Howard, Debbie R; Goodnow, Christopher C; Daley, Stephen R

2018-02-07

Acquisition of T-cell central tolerance involves distinct pathways of self-antigen presentation to thymocytes. One pathway termed indirect presentation requires a self-antigen transfer step from thymic epithelial cells (TECs) to bone marrow-derived cells before the self-antigen is presented to thymocytes. The role of indirect presentation in central tolerance is context-dependent, potentially due to variation in self-antigen expression, processing and presentation in the thymus. Here, we report experiments in mice in which TECs expressed a membrane-bound transgenic self-antigen, hen egg lysozyme (HEL), from either the insulin (insHEL) or thyroglobulin (thyroHEL) promoter. Intrathymic HEL expression was less abundant and more confined to the medulla in insHEL mice compared with thyroHEL mice. When indirect presentation was impaired by generating mice lacking MHC class II expression in bone marrow-derived antigen-presenting cells, insHEL-mediated thymocyte deletion was abolished, whereas thyroHEL-mediated deletion occurred at a later stage of thymocyte development and Foxp3 + regulatory T-cell differentiation increased. Indirect presentation increased the strength of T-cell receptor signalling that both self-antigens induced in thymocytes, as assessed by Helios expression. Hence, indirect presentation limits the differentiation of naive and regulatory T cells by promoting deletion of self-reactive thymocytes. © 2018 John Wiley & Sons Ltd.

Indirection and computer security.

Energy Technology Data Exchange (ETDEWEB)

Berg, Michael J.

2011-09-01

The discipline of computer science is built on indirection. David Wheeler famously said, 'All problems in computer science can be solved by another layer of indirection. But that usually will create another problem'. We propose that every computer security vulnerability is yet another problem created by the indirections in system designs and that focusing on the indirections involved is a better way to design, evaluate, and compare security solutions. We are not proposing that indirection be avoided when solving problems, but that understanding the relationships between indirections and vulnerabilities is key to securing computer systems. Using this perspective, we analyze common vulnerabilities that plague our computer systems, consider the effectiveness of currently available security solutions, and propose several new security solutions.

Phage-Mediated Competitive Chemiluminescent Immunoassay for Detecting Cry1Ab Toxin by Using an Anti-Idiotypic Camel Nanobody.

Science.gov (United States)

Qiu, Yulou; Li, Pan; Dong, Sa; Zhang, Xiaoshuai; Yang, Qianru; Wang, Yulong; Ge, Jing; Hammock, Bruce D; Zhang, Cunzheng; Liu, Xianjin

2018-01-31

Cry toxins have been widely used in genetically modified organisms for pest control, raising public concern regarding their effects on the natural environment and food safety. In this work, a phage-mediated competitive chemiluminescent immunoassay (c-CLIA) was developed for determination of Cry1Ab toxin using anti-idiotypic camel nanobodies. By extracting RNA from camels' peripheral blood lymphocytes, a naive phage-displayed nanobody library was established. Using anti-Cry1Ab toxin monoclonal antibodies (mAbs) against the library for anti-idiotypic antibody screening, four anti-idiotypic nanobodies were selected and confirmed to be specific for anti-Cry1Ab mAb binding. Thereafter, a c-CLIA was developed for detection of Cry1Ab toxin based on anti-idiotypic camel nanobodies and employed for sample testing. The results revealed a half-inhibition concentration of developed assay to be 42.68 ± 2.54 ng/mL, in the linear range of 10.49-307.1 ng/mL. The established method is highly specific for Cry1Ab recognition, with negligible cross-reactivity for other Cry toxins. For spiked cereal samples, the recoveries of Cry1Ab toxin ranged from 77.4% to 127%, with coefficient of variation of less than 9%. This study demonstrated that the competitive format based on phage-displayed anti-idiotypic nanobodies can provide an alternative strategy for Cry toxin detection.

Comparative TEA for Indirect Liquefaction Pathways to Distillate-Range Fuels via Oxygenated Intermediates

Energy Technology Data Exchange (ETDEWEB)

Tan, Eric; Snowden-Swan, Lesley J.; Talmadge, Michael; Dutta, Abhijit; Jones, Susanne; Ramasamy, Karthikeyan; Gray, Michael; Dagle, Robert; Padmaperuma, Asanga; Gerber, Mark; Sahir, Asad; Tao, Ling; Zhang, Yanan

2017-03-03

This paper presents a comparative techno-economic analysis of five conversion pathways from biomass to gasoline-, jet-, and diesel-range hydrocarbons via indirect liquefaction with specific focus on pathways utilizing oxygenated intermediates (derived either via thermochemical or biochemical conversion steps). The four emerging pathways of interest are compared with one conventional pathway (Fischer-Tropsch) for the production of the hydrocarbon blendstocks. The processing steps of the four emerging pathways include: biomass-to-syngas via indirect gasification, gas cleanup, conversion of syngas to alcohols/oxygenates, followed by conversion of alcohols/oxygenates to hydrocarbon blendstocks via dehydration, oligomerization, and hydrogenation. We show that the emerging pathways via oxygenated intermediates have the potential to be cost competitive with the conventional Fischer-Tropsch process. The evaluated pathways and the benchmark process generally exhibit similar fuel yields and carbon conversion efficiencies. The resulting minimum fuel selling prices are comparable to the benchmark at approximately $3.60 per gallon-gasoline equivalent, with potential for two new pathways to be more economically competitive. Additionally, the coproduct values can play an important role in the economics of the processes with oxygenated intermediates derived via syngas fermentation. Major cost drivers for the integrated processes are tied to achievable fuel yields and conversion efficiency of the intermediate steps, i.e., the production of oxygenates/alcohols from syngas and the conversion of oxygenates/alcohols to hydrocarbon fuels.

Emergency room nurses' pathway to turnover intention: a moderated serial mediation analysis.

Science.gov (United States)

Bruyneel, Luk; Thoelen, Tom; Adriaenssens, Jef; Sermeus, Walter

2017-04-01

The aim of this study was to explore the association between the quality of the work environment, job characteristics, demographic characteristics and a pathway of job satisfaction, emotional exhaustion and turnover intention among nurses in emergency departments and perform subgroup analyses. Turnover intention among nurses is high. Multiple causes have been described, mostly in large studies of nurses working on general wards, often without considering complementarity of conceptual models and showing scant interest in the consistency of associations across subgroups of nurses. Cross-sectional multicentre survey. Convenience sample of 294 nurses in 11 Belgian emergency departments during 2014-2015. Indirect effects in the form of mediation and serial mediation were estimated to assess the association between work environment (Magnet model), job characteristics (Job Demand Control Support model) and turnover intention via job satisfaction and emotional exhaustion. Consistency of these indirect effects across subgroups of nurses was examined using moderated mediation analysis (conditional indirect effects). Several Magnet and Job Demand Control Support dimensions were related to turnover intention, either via job dissatisfaction (mediation) or via job satisfaction and emotional exhaustion (serial mediation). In the case of social support from supervisor, these indirect effects were only significant for female nurses, among whom turnover intention was higher. Last, nurses with more years of experience were less likely to indicate turnover intention. To maximize prevention of turnover intention at emergency departments, interventions could target early career nurses, work environment and job characteristics. Female nurses in particular may also benefit from improved social support from their supervisor. © 2016 John Wiley & Sons Ltd.

Evaluation of the radioimmunoassay, indirect enzyme linked immunosorbent assay, and dot blot assay for the identification of Xanthomonas campestris pv. phaseoli

Energy Technology Data Exchange (ETDEWEB)

Malin, E; Belden, E L; Roth, D

1985-09-01

A radioimmunoassay (RIA), an indirect competitive enzyme-linked immunosorbent assay (ELISA), and a dot-blot modification of the ELISA were evaluated for detection and identification of Xanthomonas campestris pv. phaseoli (X. c. pv. phaseoli). RIA and the dot blot tests were specific for X. c. pv. phaseoli; however, significant cross reactions occurred in the indirect competitive ELISA when using anti-X. c. pv. phaseoli antiserum against other closely related bacteria. The sensitivity level of all procedures for X. c. pv. phaseoli was approximately l0/sup 5/ colony forming unitsmL. All procedures were unsatisfactory in reliably detecting low levels of X. c. pv. phaseoli directly from extracts of bean seed. However when used in conjunction with ilution plating the dot blot assay and the RIA would be useful in specifically identifying X. c. pv. phaseoli. The relative merits of these tests for identification of X. c. pv. phaseoli are discussed.

MP-4 Contributes to Snake Venom Neutralization by Mucuna pruriens Seeds through an Indirect Antibody-mediated Mechanism.

Science.gov (United States)

Kumar, Ashish; Gupta, Chitra; Nair, Deepak T; Salunke, Dinakar M

2016-05-20

Mortality due to snakebite is a serious public health problem, and available therapeutics are known to induce debilitating side effects. Traditional medicine suggests that seeds of Mucuna pruriens can provide protection against the effects of snakebite. Our aim is to identify the protein(s) that may be important for snake venom neutralization and elucidate its mechanism of action. To this end, we have identified and purified a protein from M. pruriens, which we have named MP-4. The full-length polypeptide sequence of MP-4 was obtained through N-terminal sequencing of peptide fragments. Sequence analysis suggested that the protein may belong to the Kunitz-type protease inhibitor family and therefore may potentially neutralize the proteases present in snake venom. Using various structural and biochemical tools coupled with in vivo assays, we are able to show that MP-4 does not afford direct protection against snake venom because it is actually a poor inhibitor of serine proteases. Further experiments showed that antibodies generated against MP-4 cross-react with the whole venom and provide protection to mice against Echis carinatus snake venom. This study shows that the MP-4 contributes significantly to the snake venom neutralization activity of M. pruriens seeds through an indirect antibody-mediated mechanism. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Immunologically mediated oral diseases.

Science.gov (United States)

Jimson, Sudha; Balachader, N; Anita, N; Babu, R

2015-04-01

Immune mediated diseases of oral cavity are uncommon. The lesions may be self-limiting and undergo remission spontaneously. Among the immune mediated oral lesions the most important are lichen planus, pemphigus, erythema multiformi, epidermolysis bullosa, systemic lupus erythematosis. Cellular and humoral mediated immunity play a major role directed against epithelial and connective tissue in chronic and recurrent patterns. Confirmatory diagnosis can be made by biopsy, direct and indirect immunoflouresence, immune precipitation and immunoblotting. Therapeutic agents should be selected after thorough evaluation of immune status through a variety of tests and after determining any aggravating or provoking factors. Early and appropriate diagnosis is important for proper treatment planning contributing to better prognosis and better quality of life of patient.

Probiotics and the Gut Immune System: Indirect Regulation.

Science.gov (United States)

La Fata, Giorgio; Weber, Peter; Mohajeri, M Hasan

2018-03-01

The gastrointestinal tract (GIT) represents the largest interface between the human organism and the external environment. In the lumen and upper part of the mucus layer, this organ hosts an enormous number of microorganisms whose composition affects the functions of the epithelial barrier and the gut immune system. Consequentially, the microorganisms in the GIT influence the health status of the organism. Probiotics are living microorganisms which, in specific conditions, confer a health benefit to the host. Among others, probiotics have immunomodulatory properties that usually act directly by (a) increasing the activity of macrophages or natural killer cells, (b) modulating the secretion of immunoglobulins or cytokines, or indirectly by (c) enhancing the gut epithelial barrier, (d) altering the mucus secretion, and (e) competitive exclusion of other (pathogenic) bacteria. This review focuses on specific bacteria strains with indirect immunomodulatory properties. Particularly, we describe here the mechanisms through which specific probiotics enhance the gut epithelial barrier and modulate mucus production. Moreover, we describe the antimicrobial properties of specific bacteria strains. Recent data suggest that multiple pathologies are associated with an unbalanced gut microflora (dysbiosis). Although the cause-effect relationship between pathology and gut microflora is not yet well established, consumption of specific probiotics may represent a powerful tool to re-establish gut homeostasis and promote gut health.

Differentiation of direct and indirect socioeconomic effects on suicide attempts in South Korea.

Science.gov (United States)

Ki, Myung; Seong Sohn, Eui; An, Byungduck; Lim, Jiseun

2017-12-01

Despite the wide recognition of the inverse association between socioeconomic position (SEP) and suicidal behaviors, its underlying process and potential mediators are little known. This study investigated the pathway from SEP to suicide attempts with attention to potential mediators.From the Korean Health and Nutrition Examination Survey 2007-2013, which is a nationwide cross-sectional survey of the health and nutritional status, a total of 34,565 participants (≥30 years) were included in the analysis. To unfold the pathways linking SEP to suicide attempts, the direct and indirect effects of 3 SEP measures (educational attainment, household income, and occupational group) and 3 mediators (physical illness, mental health problems, and problematic drinking) were differentiated using structured equation model (SEM).Most of direct and indirect effects of educational attainment, household income, and occupational group on suicide attempts were significant; Nonemployment status had the largest total (β = 0.291, P suicide attempts, compared to mental health problem and problem drinking.Overall, experience of socioeconomic disadvantage increased suicide attempts independently of mental and physical problems. An extension of suicide prevention program is required for comprehensively targeting people with general problems such as physical illness and low SEP, complemented to narrowly targeting high risk group with, such as mental health problem. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Interspecific competition alters natural selection on shade avoidance phenotypes in Impatiens capensis.

Science.gov (United States)

McGoey, Brechann V; Stinchcombe, John R

2009-08-01

Shade avoidance syndrome is a known adaptive response for Impatiens capensis growing in dense intraspecific competition. However, I. capensis also grow with dominant interspecific competitors in marshes. Here, we compare the I. capensis shade-avoidance phenotypes produced in the absence and presence of heterospecific competitors, as well as selection on those traits. Two treatments were established in a marsh; in one treatment all heterospecifics were removed, while in the other, all competitors remained. We compared morphological traits, light parameters, seed output and, using phenotypic selection analysis, examined directional and nonlinear selection operating in the different competitive treatments. Average phenotypes, light parameters and seed production all varied depending on competitive treatment. Phenotypic selection analyses revealed different directional, disruptive, stabilizing and correlational selection. The disparities seen in both phenotypes and selection between the treatments related to the important differences in elongation timing depending on the presence of heterospecifics, although environmental covariances between traits and fitness could also contribute. Phenotypes produced by I. capensis depend on their competitive environment, and differing selection on shade-avoidance traits between competitive environments could indirectly select for increased plasticity given gene flow between populations in different competitive contexts.

Accommodating Binary and Count Variables in Mediation: A Case for Conditional Indirect Effects

Science.gov (United States)

Geldhof, G. John; Anthony, Katherine P.; Selig, James P.; Mendez-Luck, Carolyn A.

2018-01-01

The existence of several accessible sources has led to a proliferation of mediation models in the applied research literature. Most of these sources assume endogenous variables (e.g., M, and Y) have normally distributed residuals, precluding models of binary and/or count data. Although a growing body of literature has expanded mediation models to…

Direct and indirect cardiovascular actions of cathinone and MDMA in the anaesthetized rat.

Science.gov (United States)

Alsufyani, Hadeel A; Docherty, James R

2015-07-05

The stimulants cathinone (from Khat leaves) and methylenedioxymeth-amphetamine (MDMA) produce adrenoceptor mediated tachycardia and vasopressor actions that may be the result of direct receptor stimulation, actions on the noradrenaline transporter, and/or displacement of noradrenaline from nerve terminals. Effects of cathinone or MDMA were compared with those of the indirect sympathomimetic tyramine. Male Wistar rats were anaesthetized with pentobarbitone for blood pressure and heart rate recording. Some rats were sympathectomised by treatment with 6-hydroxydopamine. In the anaesthetised rat, cathinone, MDMA and tyramine (all 0.001-1 mg/kg) produced marked tachycardia, tyramine produced marked pressor responses and MDMA produced small pressor responses. The tachycardia to cathinone and MDMA was almost abolished by propranolol (1mg/kg). Pretreatment with cocaine (1mg/kg) did not significantly affect the tachycardia to cathinone or MDMA, but reduced the response to tyramine. However, in sympathectomised rats, the tachycardia to cathinone or MDMA was markedly attenuated, but the tachycardia to tyramine was only partially reduced. Blood pressure effects of tyramine and MDMA were also markedly attenuated by sympathectomy. The results demonstrate firstly that cocaine may not be the most suitable agent for assessing direct versus indirect agonism in cardiovascular studies. Secondly, the use of chemical sympathectomy achieved the desired goal of demonstrating that cardiac β-adrenoceptor mediated actions of cathinone and MDMA are probably largely indirect. Copyright © 2015 Elsevier B.V. All rights reserved.

Invited commentary: boundless science--putting natural direct and indirect effects in a clearer empirical context.

Science.gov (United States)

Naimi, Ashley I

2015-07-15

Epidemiologists are increasingly using natural effects for applied mediation analyses, yet 1 key identifying assumption is unintuitive and subject to some controversy. In this issue of the Journal, Jiang and VanderWeele (Am J Epidemiol. 2015;182(2):105-108) formalize the conditions under which the difference method can be used to estimate natural indirect effects. In this commentary, I discuss implications of the controversial "cross-worlds" independence assumption needed to identify natural effects. I argue that with a binary mediator, a simple modification of the authors' approach will provide bounds for natural direct and indirect effect estimates that better reflect the capacity of the available data to support empirical statements on the presence of mediated effects. I discuss complications encountered when odds ratios are used to decompose effects, as well as the implications of incorrectly assuming the absence of exposure-induced mediator-outcome confounders. I note that the former problem can be entirely resolved using collapsible measures of effect, such as risk ratios. In the Appendix, I use previous derivations for natural direct effect bounds on the risk difference scale to provide bounds on the odds ratio scale that accommodate 1) uncertainty due to the cross-world independence assumption and 2) uncertainty due to the cross-world independence assumption and the presence of exposure-induced mediator-outcome confounders. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

TV, Social Media, and College Students' Binge Drinking Intentions: Moderated Mediation Models.

Science.gov (United States)

Yang, Bo; Zhao, Xinyan

2018-01-01

Many studies to date have examined how media influence health-related behavior through social norms. However, most studies focused on traditional media. In the era of traditional and social media integration, our study advances health and mass communication scholarship by examining the influence of both traditional and social media mediated through social norms. Also, we examined a boundary condition for the norms-mediated media influence process. Namely, in the context of college binge drinking, we predict that exposure to TV and social media prodrinking messages can influence college students' binge drinking intentions through perceived peer descriptive and injunctive norms. We also predict that group identification will moderate this indirect effect. Our moderated mediation models were tested via structural equation modeling (N = 609). We found that college students' exposure to social media prodrinking messages indirectly influenced their binge drinking intentions via perceived injunctive norms, and students' identification with their peers moderated this indirect effect. However, neither descriptive nor injunctive norms mediated the influence of students' exposure to TV prodrinking messages on their binge drinking intentions. Theoretical and practical implications of the findings are discussed.

Causal mediation analysis for longitudinal data with exogenous exposure

OpenAIRE

Bind, M.-A. C.; Vanderweele, T. J.; Coull, B. A.; Schwartz, J. D.

2015-01-01

Mediation analysis is a valuable approach to examine pathways in epidemiological research. Prospective cohort studies are often conducted to study biological mechanisms and often collect longitudinal measurements on each participant. Mediation formulae for longitudinal data have been developed. Here, we formalize the natural direct and indirect effects using a causal framework with potential outcomes that allows for an interaction between the exposure and the mediator. To allow different type...

THE CUBAN ENTERPRISE, COMPETITIVENESS, IMPROVEMENT BUSINESS AND QUALITY

Directory of Open Access Journals (Sweden)

Andrés Fernández-Companioni

2016-01-01

Full Text Available This article offers some reflections on the Cuban enterprise, its business process improvement and competitiveness that firms must have in entering the world market. It analyzes the economic policies of the last two Congresses of the Communist Party of Cuba that give importance to the role of the Cuban socialist state enterprise system. It conceptualizes the category: business. Knowledge of the categories: effectiveness, efficiency, effectiveness, competitiveness, quality and productivity must for Cuban entrepreneurs. To increase export capacity, we must address a number of factors such as quality and product innovation, the price level depends on the productivity of the inflation differential between countries and other factors with indirect effects on competitiveness, and service quality or corporate image. Are some of the mistakes made in business development in the country. Relate some of the quality awards granted in the world and which should aim to achieve the necessary visibility in international business. Relate some of the quality awards that are granted in the world and which should aim for Cuban entrepreneurs to achieve the necessary visibility in international business. It provides a table that lists the entities Award Winning Quality in Cuba until 2008. It shows a country ranking of the indicators of global competitiveness generated annually by The Global Competitiveness Report. Reasoning about the causes that led to the business improvement process (SPE (Legislative Decree 252 and Decree 281. 

The role of organizational virtuousness in organizational citizenship behavior of teachers: The test of direct and indirect effect through job satisfaction mediating

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Kooshki Abedi Sara

2016-01-01

Full Text Available The aim of this study was to test the direct and indirect effect of organizational virtuousness in organizational citizenship behaviors of teachers and propose a model with a causal connection. The population consisted of all secondary school teachers of Karaj metropolitan areas where by cluster method sampling and Morgan table 403 people selected. The aim of this study is functional and in terms of methodology is survey. Standard questionnaires used to collect data and all of them had good reliability and validity. To analyze the data confirmatory factor analysis and structural equation modeling techniques used. The results showed that schools organizational virtuousness directly affect Less and non-significant on organizational citizenship behavior of teachers. The assumed test pattern suggests that organizational virtuousness with the mediation of job satisfaction can affect the behavior of teachers' organizational citizenship behavior. The findings of this study emphasis the importance of reinforcement of schools as well as teachers' job satisfaction and organizational virtuousness.

CONCEPTUAL APPROACH OF COMPETITIVENESS AND INTERDEPENDENCE BETWEEN COMPETITION AND COMPETITIVENESS

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Tatiana GUTIUM

2017-11-01

Full Text Available This article is devoted to analysis of interdependence and correlation between competition and competitiveness, and competition’s consequences. The author analysed some authors’ visions on competitiveness, and common features between theories of competition and competitiveness. Using the synthetic indicator elaborated by author has been evaluated the competitiveness of domestic goods on the internal and external market. At the end of this article, the author has developed proposals to increase competitiveness.

Odour-based context reinstatement effects with indirect measures of memory: the curious case of rosemary.

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Ball, Linden J; Shoker, Jaswinder; Miles, Jeremy N V

2010-11-01

Previous studies examining environmental context-dependent memory (ECDM) effects using indirect measures of memory have produced inconsistent findings. We report three experiments that examined ECDM in an indirect memory paradigm (word-fragment completion) using ambient odours as environmental contexts. Expt 1 manipulated the odour present at learning and testing (rosemary or lemon) to produce reinstated-context or switched-context conditions. Reinstating rosemary led to a striking ECDM effect, indicating that indirect memory testing can be sensitive to ECDM manipulations. Odour ratings also indicated that rosemary induced a more unpleasant mood in participants than lemon. Expt 2 assessed the influence on indirect retrieval of odour-based mood induction as well as odour distinctiveness, and indicated that rosemary's capacity to promote ECDM effects appears to arise from an additive combination of its unpleasantness-inducing properties and its distinctiveness. Expt 3 partially supported these proposals. Overall, our findings indicate that some odours are capable of producing ECDM effects using indirect testing procedures. Moreover, it appears that it is the inherent proprieties of odours on dimensions such as unpleasantness and distinctiveness that mediate the emergence of ECDM effects, thereby explaining the particular potency of rosemary's mnemonic influence when it is reinstated.

G-computation demonstration in causal mediation analysis

International Nuclear Information System (INIS)

Wang, Aolin; Arah, Onyebuchi A.

2015-01-01

Recent work has considerably advanced the definition, identification and estimation of controlled direct, and natural direct and indirect effects in causal mediation analysis. Despite the various estimation methods and statistical routines being developed, a unified approach for effect estimation under different effect decomposition scenarios is still needed for epidemiologic research. G-computation offers such unification and has been used for total effect and joint controlled direct effect estimation settings, involving different types of exposure and outcome variables. In this study, we demonstrate the utility of parametric g-computation in estimating various components of the total effect, including (1) natural direct and indirect effects, (2) standard and stochastic controlled direct effects, and (3) reference and mediated interaction effects, using Monte Carlo simulations in standard statistical software. For each study subject, we estimated their nested potential outcomes corresponding to the (mediated) effects of an intervention on the exposure wherein the mediator was allowed to attain the value it would have under a possible counterfactual exposure intervention, under a pre-specified distribution of the mediator independent of any causes, or under a fixed controlled value. A final regression of the potential outcome on the exposure intervention variable was used to compute point estimates and bootstrap was used to obtain confidence intervals. Through contrasting different potential outcomes, this analytical framework provides an intuitive way of estimating effects under the recently introduced 3- and 4-way effect decomposition. This framework can be extended to complex multivariable and longitudinal mediation settings

Dissociation mediates the relationship between peer victimization and hallucinatory experiences among early adolescents

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Syudo Yamasaki

2016-06-01

Full Text Available Peer victimization increases the risk of experiencing psychotic symptoms among clinical and general populations, but the mechanism underlying this association remains unclear. Dissociation, which is related to peer victimization and hallucinatory experiences, has been demonstrated as a significant mediator in the relation between childhood victimization and hallucinatory experience among adult patients with psychosis. However, no studies have examined the mediating effect of dissociation in a general early adolescent population. We examined whether dissociation mediates the relationship between peer victimization and hallucinatory experiences among 10-year-old adolescents using a population-based cross-sectional survey of early adolescents and their main parent (Tokyo Early Adolescence Survey; N = 4478. We examined the mediating effect of dissociation, as well as external locus of control and depressive symptoms, on the relationship between peer victimization and hallucinatory experiences using path analysis. The model assuming mediation effects indicated good model fit (comparative fit index = .999; root mean square error of approximation = .015. The mediation effect between peer victimization and hallucination via dissociation (standardized indirect effect = .038, p < .001 was statistically significant, whereas the mediation effects of depressive symptoms (standardized indirect effect = −.0066, p = 0.318 and external locus of control (standardized indirect effect = .0024, p = 0.321 were not significant. These results suggest that dissociation is a mediator in the relation between peer victimization and hallucinatory experiences in early adolescence. For appropriate intervention strategies, assessing dissociation and peer victimization as they affect hallucinatory experiences is necessary.

Behavioral Self-Regulation and Weight-Related Behaviors in Inner-City Adolescents: A Model of Direct and Indirect Effects.

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Isasi, Carmen R; Wills, Thomas A

2011-08-01

BACKGROUND: This study examined the association of two distinct self-regulation constructs, effortful control and dysregulation, with weight-related behaviors in adolescents and tested whether these effects were mediated by self-efficacy variables. METHODS: A school-based survey was conducted with 1771 adolescents from 11 public schools in the Bronx, New York. Self-regulation was assessed by multiple indicators and defined as two latent constructs. Dependent variables included fruit/vegetable intake, intake of snack/junk food, frequency of physical activity, and time spent in sedentary behaviors. Structural equation modeling examined the relation of effortful control and dysregulation to lifestyle behaviors, with self-efficacy variables as possible mediators. RESULTS: Study results showed that effortful control had a positive indirect effect on fruit and vegetable intake, mediated by self-efficacy, as well as a direct effect. Effortful control also had a positive indirect effect on physical activity, mediated by self-efficacy. Dysregulation had direct effects on intake of junk food/snacks and time spent in sedentary behaviors. CONCLUSIONS: These findings indicate that self-regulation characteristics are related to diet and physical activity and that some of these effects are mediated by self-efficacy. Different effects were noted for the two domains of self-regulation. Prevention researchers should consider including self-regulation processes in programs to improve health behaviors in adolescents.

PA1 Protein, a New Competitive Decelerator Acting at More than One Step to Impede Glucocorticoid Receptor-mediated Transactivation*

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Zhang, Zhenhuan; Sun, Yunguang; Cho, Young-Wook; Chow, Carson C.; Simons, S. Stoney

2013-01-01

Numerous cofactors modulate the gene regulatory activity of glucocorticoid receptors (GRs) by affecting one or more of the following three major transcriptional properties: the maximal activity of agonists (Amax), the potency of agonists (EC50), and the partial agonist activity of antisteroids (PAA). Here, we report that the recently described nuclear protein, Pax2 transactivation domain interaction protein (PTIP)-associated protein 1 (PA1), is a new inhibitor of GR transactivation. PA1 suppresses Amax, increases the EC50, and reduces the PAA of an exogenous reporter gene in a manner that is independent of associated PTIP. PA1 is fully active with, and strongly binds to, the C-terminal half of GR. PA1 reverses the effects of the coactivator TIF2 on GR-mediated gene induction but is unable to augment the actions of the corepressor SMRT. Analysis of competition assays between PA1 and TIF2 with an exogenous reporter indicates that the kinetic definition of PA1 action is a competitive decelerator at two sites upstream from where TIF2 acts. With the endogenous genes IGFBP1 and IP6K3, PA1 also represses GR induction, increases the EC50, and decreases the PAA. ChIP and re-ChIP experiments indicate that PA1 accomplishes this inhibition of the two genes via different mechanisms as follows: PA1 appears to increase GR dissociation from and reduce GR transactivation at the IGFBP1 promoter regions but blocks GR binding to the IP6K3 promoter. We conclude that PA1 is a new competitive decelerator of GR transactivation and can act at more than one molecularly defined step in a manner that depends upon the specific gene. PMID:23161582

PA1 protein, a new competitive decelerator acting at more than one step to impede glucocorticoid receptor-mediated transactivation.

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Zhang, Zhenhuan; Sun, Yunguang; Cho, Young-Wook; Chow, Carson C; Simons, S Stoney

2013-01-04

Numerous cofactors modulate the gene regulatory activity of glucocorticoid receptors (GRs) by affecting one or more of the following three major transcriptional properties: the maximal activity of agonists (A(max)), the potency of agonists (EC(50)), and the partial agonist activity of antisteroids (PAA). Here, we report that the recently described nuclear protein, Pax2 transactivation domain interaction protein (PTIP)-associated protein 1 (PA1), is a new inhibitor of GR transactivation. PA1 suppresses A(max), increases the EC(50), and reduces the PAA of an exogenous reporter gene in a manner that is independent of associated PTIP. PA1 is fully active with, and strongly binds to, the C-terminal half of GR. PA1 reverses the effects of the coactivator TIF2 on GR-mediated gene induction but is unable to augment the actions of the corepressor SMRT. Analysis of competition assays between PA1 and TIF2 with an exogenous reporter indicates that the kinetic definition of PA1 action is a competitive decelerator at two sites upstream from where TIF2 acts. With the endogenous genes IGFBP1 and IP6K3, PA1 also represses GR induction, increases the EC(50), and decreases the PAA. ChIP and re-ChIP experiments indicate that PA1 accomplishes this inhibition of the two genes via different mechanisms as follows: PA1 appears to increase GR dissociation from and reduce GR transactivation at the IGFBP1 promoter regions but blocks GR binding to the IP6K3 promoter. We conclude that PA1 is a new competitive decelerator of GR transactivation and can act at more than one molecularly defined step in a manner that depends upon the specific gene.

Trust, Commitment and Competitive Advantage in SMEs Export Performance

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Md Daud Ismail

2017-04-01

Full Text Available The entry of small businesses into international markets has intensified. However, despite the growing presence of small businesses in international markets, studies into their international behavior, particularly regarding the effect of international relationships on international outcomes, remain limited. This study investigates the cross-border relationships of Small and Medium Enterprises (SMEs by examining the effects of the dimensions of the key relationship on the competitive advantage and performance of SMEs in export markets. These dimensions include trust and commitment. Results indicate that trust is significantly related to commitment and export performance. Commitment is positively related to competitive advantage but not to export performance. Trust affects competitive advantage through commitment. The effect of commitment on export performance is mediated by competitive advantage. The methodology and results are presented. The conclusion, implications, and limitations of this study are also discussed.

Immunologically mediated oral diseases

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Sudha Jimson

2015-01-01

Full Text Available Immune mediated diseases of oral cavity are uncommon. The lesions may be self-limiting and undergo remission spontaneously. Among the immune mediated oral lesions the most important are lichen planus, pemphigus, erythema multiformi, epidermolysis bullosa, systemic lupus erythematosis. Cellular and humoral mediated immunity play a major role directed against epithelial and connective tissue in chronic and recurrent patterns. Confirmatory diagnosis can be made by biopsy, direct and indirect immunoflouresence, immune precipitation and immunoblotting. Therapeutic agents should be selected after thorough evaluation of immune status through a variety of tests and after determining any aggravating or provoking factors. Early and appropriate diagnosis is important for proper treatment planning contributing to better prognosis and better quality of life of patient.

Depression and pain: testing of serial multiple mediators.

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Wongpakaran, Tinakon; Wongpakaran, Nahathai; Tanchakvaranont, Sitthinant; Bookkamana, Putipong; Pinyopornpanish, Manee; Wannarit, Kamonporn; Satthapisit, Sirina; Nakawiro, Daochompu; Hiranyatheb, Thanita; Thongpibul, Kulvadee

2016-01-01

Despite the fact that pain is related to depression, few studies have been conducted to investigate the variables that mediate between the two conditions. In this study, the authors explored the following mediators: cognitive function, self-sacrificing interpersonal problems, and perception of stress, and the effects they had on pain symptoms among patients with depressive disorders. An analysis was performed on the data of 346 participants with unipolar depressive disorders. The 17-item Hamilton Depression Rating Scale, Mini-Mental State Examination, the pain subscale of the health-related quality of life (SF-36), the self-sacrificing subscale of the Inventory of Interpersonal Problems, and the Perceived Stress Scale were used. Parallel multiple mediator and serial multiple mediator models were used. An alternative model regarding the effect of self-sacrificing on pain was also proposed. Perceived stress, self-sacrificing interpersonal style, and cognitive function were found to significantly mediate the relationship between depression and pain, while controlling for demographic variables. The total effect of depression on pain was significant. This model, with an additional three mediators, accounted for 15% of the explained variance in pain compared to 9% without mediators. For the alternative model, after controlling for the mediators, a nonsignificant total direct effect level of self-sacrificing was found, suggesting that the effect of self-sacrificing on pain was based only on an indirect effect and that perceived stress was found to be the strongest mediator. Serial mediation may help us to see how depression and pain are linked and what the fundamental mediators are in the chain. No significant, indirect effect of self-sacrificing on pain was observed, if perceived stress was not part of the depression and/or cognitive function mediational chain. The results shown here have implications for future research, both in terms of testing the model and in

Natural enemy-mediated indirect interactions among prey species: potential for enhancing biocontrol services in agroecosystems

NARCIS (Netherlands)

Chailleux, A.; Mohl, E.K.; Teixeira Alves, M.; Messelink, G.J.; Desneux, N.

2014-01-01

Understanding how arthropod pests and their natural enemies interact in complex agroecosystems is essential for pest management programmes. Theory predicts that prey sharing a predator, such as a biological control agent, can indirectly reduce each other's density at equilibrium (apparent

Comparison of methods for the analysis of relatively simple mediation models.

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Rijnhart, Judith J M; Twisk, Jos W R; Chinapaw, Mai J M; de Boer, Michiel R; Heymans, Martijn W

2017-09-01

Statistical mediation analysis is an often used method in trials, to unravel the pathways underlying the effect of an intervention on a particular outcome variable. Throughout the years, several methods have been proposed, such as ordinary least square (OLS) regression, structural equation modeling (SEM), and the potential outcomes framework. Most applied researchers do not know that these methods are mathematically equivalent when applied to mediation models with a continuous mediator and outcome variable. Therefore, the aim of this paper was to demonstrate the similarities between OLS regression, SEM, and the potential outcomes framework in three mediation models: 1) a crude model, 2) a confounder-adjusted model, and 3) a model with an interaction term for exposure-mediator interaction. Secondary data analysis of a randomized controlled trial that included 546 schoolchildren. In our data example, the mediator and outcome variable were both continuous. We compared the estimates of the total, direct and indirect effects, proportion mediated, and 95% confidence intervals (CIs) for the indirect effect across OLS regression, SEM, and the potential outcomes framework. OLS regression, SEM, and the potential outcomes framework yielded the same effect estimates in the crude mediation model, the confounder-adjusted mediation model, and the mediation model with an interaction term for exposure-mediator interaction. Since OLS regression, SEM, and the potential outcomes framework yield the same results in three mediation models with a continuous mediator and outcome variable, researchers can continue using the method that is most convenient to them.

The Direct and Indirect Effects of Paliperidone Extended-release on Depressive Symptoms in Schizoaffective Disorder: A Path Analysis.

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Turkoz, Ibrahim; Fu, Dong-Jing; Bossie, Cynthia A; Alphs, Larry

2015-01-01

This analysis evaluates improvement in symptoms of depression in patients with schizoaffective disorder administered oral paliperidone extended-release by accounting for the magnitude of direct and indirect (changes in negative and positive symptoms and worsening of extrapyramidal symptoms) treatment effects on depressive symptoms. Data for this post hoc analysis were drawn from two six-week, randomized, placebo-controlled studies of paliperidone extended-release versus placebo in adult subjects with schizoaffective disorder (N=614; NCT00412373, NCT00397033). Subjects with baseline 17-item Hamilton Rating Scale for Depression scores of 16 or greater were included. Structural equation models (path analyses) were used to separate total effects into direct and indirect effects on depressive symptoms. Change from baseline in 17-item Hamilton Rating Scale for Depression score at the Week 6 end point was the dependent variable; changes in Positive and Negative Syndrome Scale positive and negative factors and Simpson-Angus Scale (to evaluate extrapyramidal symptoms) scores were independent variables. At baseline, 332 of 614 (54.1%) subjects had a 17-item Hamilton Rating Scale for Depression score of 16 or greater. Path analysis determined that up to 26.4 percent of the paliperidone extended-release versus placebo effect on depressive symptoms may be attributed to a direct treatment effect, and 45.8 percent and 28.4 percent were mediated indirectly through improvements on positive and negative symptoms, respectively. No effects were identified as mediated through extrapyramidal symptoms changes (-0.7%). RESULTS of this analysis suggest that paliperidone's effect on depressive symptoms in subjects with schizoaffective disorder participating in two six-week, randomized, placebo-controlled studies is mediated through indirect effects (e.g., positive and negative symptom changes) and a direct treatment effect.

Indirect effects of an invasive annual grass on seed fates of two native perennial grass species.

Science.gov (United States)

Meyer, Susan E; Merrill, Katherine T; Allen, Phil S; Beckstead, Julie; Norte, Anna S

2014-04-01

Invasive plants exhibit both direct and indirect negative effects on recruitment of natives following invasion. We examined indirect effects of the invader Bromus tectorum (cheatgrass) on seed fates of two native grass species, Elymus elymoides and Pseudoroegneria spicata, by removing B. tectorum and by adding inoculum of the shared seed pathogen Pyrenophora semeniperda in factorial experiments at xeric and mesic field sites. We also included a supplemental watering treatment to increase emergence and also the potential for pathogen escape. We recorded emergence and survival of native seedlings and also determined the fate of unemerged seeds. At the xeric site, Pyrenophora-caused mortality was high (34%), and effects of other pathogens and failed emergence of germinants were smaller. Cheatgrass removal negatively affected both emergence (35 vs. 25%) and spring survival (69 vs. 42%). Pyrenophora-caused seed mortality increased with inoculum augmentation for both species (22 vs. 47% overall), but emergence was negatively impacted only for P. spicata (20 vs. 34%). At the mesic site, Pyrenophora-caused mortality was low (6%). Cheatgrass removal doubled emergence (26 vs. 14%). Seed mortality increased significantly with inoculum augmentation for P. spicata (12 vs. 5%) but not E. elymoides, while emergence was not significantly affected in either species. A large fraction of seeds produced germinants that failed to emerge (37%), while another large fraction (35%) was killed by other pathogens. We conclude that facilitation by cheatgrass at the xeric site but interference at the mesic site was probably mediated through litter effects that could be ameliorative or suppressive. Apparent competition between cheatgrass and native grasses could occur through Pyrenophora, especially in a xeric environment, but effects were weak or absent at emergence. This was probably because Pyrenophora attacks the same slow-germinating fraction that is subject to pre-emergence mortality from

Mindfully Green and Healthy: An Indirect Path from Mindfulness to Ecological Behavior

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Sonja M. Geiger

2018-01-01

Full Text Available This paper examines the nature of the link between mindfulness and ecological behavior. Based on the notion that mindfulness incorporates heightened awareness of bodily sensations, we suggest an indirect path from mindfulness to ecological behavior that is mediated through individual health behavior, such as improved nutrition and increased exercise. This indirect path is corroborated with two online studies (n = 147/n = 239 where mindfulness, personal health behavior and ecological behavior were assessed. We conclude that increased mindful awareness of momentary experience indeed favors more healthy lifestyles, which in turn relate to increased ecological behavior beyond personal health benefits. The findings support an agreeableness of personal and planetary health behavior and open up a path for environmental educational interventions based on mindfulness practices and personal health gains.

From pioneering orientation to new product performance through competitive tactics in SMEs

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Pedro M. García-Villaverde

2017-10-01

Full Text Available The literature regarding entry timing suggests that pioneering orientation (PO is a key determinant factor of new product performance (NPP due to ‘first mover advantages’. The contradictory results and specific biases raise a research gap on which conditions and processes lead PO to a higher NPP. This paper proposes to fill this gap by designing and testing a model examining to what extent development of competitive tactics drive and explain the way from PO to NPP. We test the model on a sample of 224 footwear firms. Results show that, separately, each of the competitive tactics has a total mediating effect linking PO with NPP. Introducing the competitive tactics into a multiple mediator model the routes from PO to NPP through low cost and innovation differentiation are relevant and compatible. However, marketing differentiation is less effective. The study provides new ways of linking the entry timing and advantage strategy perspectives.

Religiousness and hazardous alcohol use: a conditional indirect effects model.

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Jankowski, Peter J; Hardy, Sam A; Zamboanga, Byron L; Ham, Lindsay S

2013-08-01

The current study examined a conditional indirect effects model of the association between religiousness and adolescents' hazardous alcohol use. In doing so, we responded to the need to include both mediators and moderators, and the need for theoretically informed models when examining religiousness and adolescents' alcohol use. The sample consisted of 383 adolescents, aged 15-18, who completed an online questionnaire. Results of structural equation modeling supported the proposed model. Religiousness was indirectly associated with hazardous alcohol use through both positive alcohol expectancy outcomes and negative alcohol expectancy valuations. Significant moderating effects for alcohol expectancy valuations on the association between alcohol expectancies and alcohol use were also found. The effects for alcohol expectancy valuations confirm valuations as a distinct construct to that of alcohol expectancy outcomes, and offer support for the protective role of internalized religiousness on adolescents' hazardous alcohol use as a function of expectancy valuations. Copyright © 2013 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Competitive interactions are mediated in a sex-specific manner by arbuscular mycorrhiza in Antennaria dioica

OpenAIRE

Varga, S.; Vega-Frutis, R.; Kytöviita, M.-M.; Franken, P.

2017-01-01

Plants usually interact with other plants, and the outcome of such interaction ranges from facilitation to competition depending on the identity of the plants, including their sexual expression. Arbuscular mycorrhizal (AM) fungi have been shown to modify competitive interactions in plants. However, few studies have evaluated how AM fungi influence plant intraspecific and interspecific interactions in dioecious species. The competitive abilities of female and male plants of Antennaria dioic...

The relationship among customer demand, competitive strategy and manufacturing system functional objectives

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Wei Xu

2013-09-01

Full Text Available Purpose: To ascertain the relationship between the operation system function goal decision making and customer demand and competition strategy, can better discover and integrate all available resources (including important capital resources to achieve business opportunities, the establishment of sustainable competitive ability. Because, to achieve business development lead policymakers take great uncertainty, which led to the investment behavior required for the operational activities of resources also bear the enormous risks. Design/methodology/approach: Through principal component analysis on the data collected by questionnaires, the manuscript obtains dominant factors for customer demand, competitive strategy and manufacturing system functional objectives respectively. By these factors, it tests its three hypotheses with the data from northeast of China and draws some conclusions. Findings: The results show that customer demand have a significant positive effect on competitive strategy; competitive strategy have positive influence on manufacturing system functional objectives; customer demand affect the functional objectives, by competitive strategy. Research limitations/implications: In this research, competitive strategy and manufacturing system functional objectives are influenced by customer demand. The conclusion of the research can provide theoretical guidance for Chinese enterprises which carry out manufacturing system functional objectives. Originality/value: In this research, a new measure questionnaire of competition strategy, customer satisfaction and operating system function goal was used, analyzed the influence factors of time, quality, cost, efficiency, service and environment, on the operation of the system. The study shows that the effect of competition strategy and customer demand has a direct impact on the operating system functions, customer demand through competitive strategy of indirect effects operating system functions.

An ATP Binding Cassette Transporter Mediates the Uptake of α-(1,6)-Linked Dietary Oligosaccharides in Bifidobacterium and Correlates with Competitive Growth on These Substrates

DEFF Research Database (Denmark)

Hansen, Morten Ejby; Fredslund, Folmer; Andersen, Joakim Mark

2016-01-01

that the dominant HGM commensal Bacteroides ovatus was out-competed by B. animalis subsp. lactis Bl-04 in mixed cultures growing on raffinose, the preferred ligand for the BlG16BP. By comparison, B. ovatus mono-cultures grew very efficiently on this trisaccharide. These findings suggest that the ABC-mediated uptake...... of raffinose provides an important competitive advantage, particularly against dominant Bacteroides that lack glycan-specific ABC-transporters. This novel insight highlights the role of glycan transport in defining the metabolic specialization of gut bacteria....

Agrochemicals indirectly increase survival of E. coli O157:H7 and indicator bacteria by reducing ecosystem services.

Science.gov (United States)

Staley, Zachery R; Rohr, Jason R; Senkbeil, Jacob K; Harwood, Valerie J

Storm water and agricultural runoff frequently contain agrochemicals, fecal indicator bacteria (FIB), and zoonotic pathogens. Entry of such contaminants into aquatic ecosystems may affect ecology and human health. This study tested the hypothesis that the herbicide atrazine and the fungicide chlorothalonil indirectly affect the survival of FIB (Escherichia coli and Enterococcus faecalis) and a pathogen (E. coli O157:H7) by altering densities of protozoan predators or by altering competition from autochthonous bacteria. Streptomycin-resistant E. coli, En. faecalis, and E. coli O157:H7 were added to microcosms composed of Florida river water containing natural protozoan and bacterial populations. FIB, pathogen, and protozoan densities were monitored over six days. Known metabolic inhibitors, cycloheximide and streptomycin, were used to inhibit autochthonous protozoa or bacteria, respectively. The inhibitors made it possible to isolate the effects of predation or competition on survival of allochthonous bacteria, and each treatment increased the survival of FIB and pathogens. Chlorothalonil's effect was similar to that of cycloheximide, significantly reducing protozoan densities and elevating densities of FIB and pathogens relative to the control. Atrazine treatment did not affect protozoan densities, but, through an effect on competition, resulted in significantly greater densities of En. faecalis and E. coli O157:H7. Hence, by reducing predaceous protozoa and bacterial competitors that facilitate purifying water bodies of FIBs and human pathogens, chlorothalonil and atrazine indirectly diminished an ecosystem service of fresh water.

IT infrastructure and competitive aggressiveness in explaining and predicting performance

NARCIS (Netherlands)

Ajamieh, Aseel; Benitez, Jose; Braojos, Jessica; Gelhard, Carsten Volker

2016-01-01

While prior Information Systems and Operations Management literature emphasizes the role of both the firm's IT infrastructure and the general degree of competition as antecedents of firm performance, the organizational capabilities that mediate these important relationships remain undetermined.

Efficient nonparametric estimation of causal mediation effects

OpenAIRE

Chan, K. C. G.; Imai, K.; Yam, S. C. P.; Zhang, Z.

2016-01-01

An essential goal of program evaluation and scientific research is the investigation of causal mechanisms. Over the past several decades, causal mediation analysis has been used in medical and social sciences to decompose the treatment effect into the natural direct and indirect effects. However, all of the existing mediation analysis methods rely on parametric modeling assumptions in one way or another, typically requiring researchers to specify multiple regression models involving the treat...

Statistical Power for Causally Defined Indirect Effects in Group-Randomized Trials with Individual-Level Mediators

Science.gov (United States)

Kelcey, Benjamin; Dong, Nianbo; Spybrook, Jessaca; Cox, Kyle

2017-01-01

Designs that facilitate inferences concerning both the total and indirect effects of a treatment potentially offer a more holistic description of interventions because they can complement "what works" questions with the comprehensive study of the causal connections implied by substantive theories. Mapping the sensitivity of designs to…

Integrating mediation and moderation to advance theory development and testing.

Science.gov (United States)

Karazsia, Bryan T; Berlin, Kristoffer S; Armstrong, Bridget; Janicke, David M; Darling, Katherine E

2014-03-01

The concepts and associated analyses of mediation and moderation are important to the field of psychology. Although pediatric psychologists frequently incorporate mediation and moderation in their theories and empirical research, on few occasions have we integrated mediation and moderation. In this article, conceptual reasons for integrating mediation and moderation are offered. We illustrate a model that integrates mediation and moderation. In our illustration, the strength of an indirect or a mediating effect varied as a function of a moderating variable. Clinical implications of the integration of mediation and moderation are discussed, as is the potential of integrated models to advance research programs in pediatric psychology.

ORGANISATIONAL CAPABILITIES, COMPETITIVE ADVANTAGE AND PERFORMANCE IN SUPPORTING INDUSTRIES IN VIETNAM

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Nham Phong Tuan

2010-01-01

Full Text Available This paper focuses on applying the resource-based view (RBV of firms to explain performance in supporting industries in Vietnam. Specifically, we based our research on the comprehensive framework of RBV and reviewed previous empirical researches before deciding on adopting a dynamic capabilities approach to test relationships among organisational capabilities, competitive advantage and performance. A multivariate analysis of survey responses of 102 firms belonging to supporting industries in Vietnam indicates that the organisational capabilities are related to the competitive advantage, that the competitive advantage is related to performance, and that the competitive advantage mediates the relationship between organizational capabilities and performance. These findings have considerable implications for academics as well as practitioners. Finally, this study also provides directions for future research.

Perceived parental monitoring and adolescent internet addiction: A moderated mediation model.

Science.gov (United States)

Ding, Qingwen; Li, Dongping; Zhou, Yueyue; Dong, Hongning; Luo, Jinjing

2017-11-01

Bronfenbrenner's (1979) ecological model focuses on the interrelation between different contexts and the interaction between individuals and their proximal contexts. Based on this theory, the present study tested a moderated mediation model of family, peer, and individual characteristics to investigate how they impact adolescent Internet addiction. Specifically, we examined whether deviant peer affiliation partially mediated the relation between perceived parental monitoring and adolescent Internet addiction, and whether this indirect relation was moderated by effortful control. A total of 747 Chinese middle school students filled out anonymous questionnaires concerning perceived parental monitoring, deviant peer affiliation, effortful control, and Internet addiction. The findings indicated that while the impact of parental monitoring on Internet addiction was partially mediated by deviant peer affiliation, effortful control moderated the first stage of the indirect relationship. For low effortful control adolescents, perceived parental monitoring negatively predicted deviant peer affiliation. Conversely, the indirect path was not significant for high effortful control adolescents. These findings highlight the need to consider family, peer and individual factors simultaneously when evaluating risks associated with adolescent Internet addiction and have important implications for the prevention and intervention of adolescent Internet addiction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multiple mediation analysis of the relationship between rapid naming and reading

DEFF Research Database (Denmark)

Poulsen, Mads; Juul, Holger; Elbro, Carsten

2015-01-01

It is well established that rapid automatised naming (RAN) correlates with reading ability. Despite several attempts, no single component process (mediator) has been identified that fully accounts for the correlation. The present paper estimated the explanatory value of several mediators....... The influence of the mediators on the RAN-reading correlation was estimated as indirect effects in mediation analyses. Phonological awareness and letter knowledge significantly mediated the RAN-reading relationship, each accounted for a moderate part of the correlation between RAN and reading fluency. Thus...

The impact of parenting styles on children developmental outcome: The role of academic self-concept as a mediator.

Science.gov (United States)

Sangawi, Hoshiar; Adams, John; Reissland, Nadja

2016-08-23

Although the importance of parenting styles directly influencing child development is well established, fewer studied have examined whether parenting styles also affect children's behavioural problems indirectly, mediated through children's academic self-concept (ASC). We examined direct and shared effects of parenting styles on behavioural problems of 199 Kurdish primary school children with a mean age of 11 years 7 months (range 11 years 5 months to 12 years 3 months). Questionnaires measured parenting styles (child version of Alabama Parenting Questionnaire), assessed children's ASC (Myself-As-Learner Scale) and identified children's behavioural problems with the Strengths and Difficulties Questionnaire (SDQ). PROCESS analysis was used to perform the mediation analysis. The results revealed that positive and negative parenting composites are indirectly related to children's internalising behaviour problems. In addition, ASC partially mediated the relationship between the negative parenting composite and prosocial behaviour. However, the mediation analysis did not show the expected indirect effect of parenting styles on externalising problems as being mediated via ASC. Hence, we argue that the ASC serves as a significant mediator in the relationship between parenting styles with prosocial behaviour and internalising problems. © 2016 International Union of Psychological Science.

Cruel intentions on television and in real life: can viewing indirect aggression increase viewers' subsequent indirect aggression?

Science.gov (United States)

Coyne, Sarah M; Archer, John; Eslea, Mike

2004-07-01

Numerous studies have shown that viewing violence in the media can influence an individual's subsequent aggression, but none have examined the effect of viewing indirect aggression. This study examines the immediate effect of viewing indirect and direct aggression on subsequent indirect aggression among 199 children ages 11 to 14 years. They were shown an indirect, direct, or no-aggression video and their subsequent indirect aggression was measured by negative evaluation of a confederate and responses to a vignette. Participants viewing indirect or direct aggression gave a more negative evaluation of and less money to a confederate than participants viewing no-aggression. Participants viewing indirect aggression gave less money to the confederate than those viewing direct aggression. Participants viewing indirect aggression gave more indirectly aggressive responses to an ambiguous situation and participants viewing direct aggression gave more directly aggressive responses. This study provides the first evidence that viewing indirect aggression in the media can have an immediate impact on subsequent aggression.

Confounding and Statistical Significance of Indirect Effects: Childhood Adversity, Education, Smoking, and Anxious and Depressive Symptomatology

Directory of Open Access Journals (Sweden)

Mashhood Ahmed Sheikh

2017-08-01

Full Text Available The life course perspective, the risky families model, and stress-and-coping models provide the rationale for assessing the role of smoking as a mediator in the association between childhood adversity and anxious and depressive symptomatology (ADS in adulthood. However, no previous study has assessed the independent mediating role of smoking in the association between childhood adversity and ADS in adulthood. Moreover, the importance of mediator-response confounding variables has rarely been demonstrated empirically in social and psychiatric epidemiology. The aim of this paper was to (i assess the mediating role of smoking in adulthood in the association between childhood adversity and ADS in adulthood, and (ii assess the change in estimates due to different mediator-response confounding factors (education, alcohol intake, and social support. The present analysis used data collected from 1994 to 2008 within the framework of the Tromsø Study (N = 4,530, a representative prospective cohort study of men and women. Seven childhood adversities (low mother's education, low father's education, low financial conditions, exposure to passive smoke, psychological abuse, physical abuse, and substance abuse distress were used to create a childhood adversity score. Smoking status was measured at a mean age of 54.7 years (Tromsø IV, and ADS in adulthood was measured at a mean age of 61.7 years (Tromsø V. Mediation analysis was used to assess the indirect effect and the proportion of mediated effect (% of childhood adversity on ADS in adulthood via smoking in adulthood. The test-retest reliability of smoking was good (Kappa: 0.67, 95% CI: 0.63; 0.71 in this sample. Childhood adversity was associated with a 10% increased risk of smoking in adulthood (Relative risk: 1.10, 95% CI: 1.03; 1.18, and both childhood adversity and smoking in adulthood were associated with greater levels of ADS in adulthood (p < 0.001. Smoking in adulthood did not significantly

Acrolein Causes TRPA1-Mediated Sensory Irritation and Indirect Potentiation of TRPV1-Mediated Pulmonary Chemoreflex Response

Science.gov (United States)

We previously demonstrated that acute exposure to acrolein causes immediate sensory irritation, with rapid decrease in heart rate (HR) and increase in inspiratory time (Ti), and potentiation of pulmonary chemoreflex response 24hrs later; of these effects only the latter is mediat...

Transforming Environmental Knowledge into Behavior: The Mediating Role of Environmental Emotions

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Carmi, Nurit; Arnon, Sara; Orion, Nir

2015-01-01

The present study was based on the premise that environmental knowledge can drive environmental behavior only if it arouses environmental emotions. Using a structural equations modeling approach, we tested the direct, as well as the indirect (mediated) effects of knowledge on behavior and assessed the mediating role of environmental emotions. We…

Impact of mass generation for spin-1 mediator simplified models

International Nuclear Information System (INIS)

Bell, Nicole F.; Cai, Yi; Leane, Rebecca K.

2017-01-01

In the simplified dark matter models commonly studied, the mass generation mechanism for the dark fields is not typically specified. We demonstrate that the dark matter interaction types, and hence the annihilation processes relevant for relic density and indirect detection, are strongly dictated by the mass generation mechanism chosen for the dark sector particles, and the requirement of gauge invariance. We focus on the class of models in which fermionic dark matter couples to a spin-1 vector or axial-vector mediator. However, in order to generate dark sector mass terms, it is necessary in most cases to introduce a dark Higgs field and thus a spin-0 scalar mediator will also be present. In the case that all the dark sector fields gain masses via coupling to a single dark sector Higgs field, it is mandatory that the axial-vector coupling of the spin-1 mediator to the dark matter is non-zero; the vector coupling may also be present depending on the charge assignments. For all other mass generation options, only pure vector couplings between the spin-1 mediator and the dark matter are allowed. If these coupling restrictions are not obeyed, unphysical results may be obtained such as a violation of unitarity at high energies. These two-mediator scenarios lead to important phenomenology that does not arise in single mediator models. We survey two-mediator dark matter models which contain both vector and scalar mediators, and explore their relic density and indirect detection phenomenology.

Is Nocturnal Foraging in a Tropical Bee an Escape From Interference Competition?

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Smith, Adam R; Kitchen, Shannon M; Toney, Ryan M; Ziegler, Christian

2017-01-01

Temporal niche partitioning may result from interference competition if animals shift their activity patterns to avoid aggressive competitors. If doing so also shifts food sources, it is difficult to distinguish the effects of interference and consumptive competition in selecting for temporal niche shift. Bees compete for pollen and nectar from flowers through both interference and consumptive competition, and some species of bees have evolved nocturnality. Here, we use tropical forest canopy towers to observe bees (the night-flying sweat bees Megalopta genalis and M. centralis [Halictidae], honey bees, and stingless bees [Apidae]) visiting flowers of the balsa tree (Ochroma pyramalidae, Malvaceae). Because Ochroma flowers are open in the late afternoon through the night we can test the relative influence of each competition type on temporal nice. Niche shift due to consumptive competition predicts that Megalopta forage when resources are available: from afternoon into the night. Niche shift due to interference competition predicts that Megalopta forage only in the absence of diurnal bees. We found no overlap between diurnal bees and Megalopta in the evening, and only one instance of overlap in the morning, despite the abundance of pollen and nectar in the late afternoon and evening. This supports the hypothesis that Megalopta are avoiding interference competition, but not the hypothesis that they are limited by consumptive competition. We propose that the release from interference competition enables Megalopta to provision cells quickly, and spend most of their time investing in nest defense. Thus, increases in foraging efficiency directly resulting from temporal shifts to escape interference competition may indirectly lead to reduced predation and parasitism. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Competition as a source of constraint on life history evolution in natural populations.

Science.gov (United States)

Wilson, A J

2014-01-01

Competition among individuals is central to our understanding of ecology and population dynamics. However, it could also have major implications for the evolution of resource-dependent life history traits (for example, growth, fecundity) that are important determinants of fitness in natural populations. This is because when competition occurs, the phenotype of each individual will be causally influenced by the phenotypes, and so the genotypes, of competitors. Theory tells us that indirect genetic effects arising from competitive interactions will give rise to the phenomenon of 'evolutionary environmental deterioration', and act as a source of evolutionary constraint on resource-dependent traits under natural selection. However, just how important this constraint is remains an unanswered question. This article seeks to stimulate empirical research in this area, first highlighting some patterns emerging from life history studies that are consistent with a competition-based model of evolutionary constraint, before describing several quantitative modelling strategies that could be usefully applied. A recurrent theme is that rigorous quantification of a competition's impact on life history evolution will require an understanding of the causal pathways and behavioural processes by which genetic (co)variance structures arise. Knowledge of the G-matrix among life history traits is not, in and of itself, sufficient to identify the constraints caused by competition.

No time for candy: passionfruit (Passiflora edulis) plants down-regulate damage-induced extra floral nectar production in response to light signals of competition.

Science.gov (United States)

Izaguirre, Miriam M; Mazza, Carlos A; Astigueta, María S; Ciarla, Ana M; Ballaré, Carlos L

2013-09-01

Plant fitness is often defined by the combined effects of herbivory and competition, and plants must strike a delicate balance between their ability to capture limiting resources and defend against herbivore attack. Many plants use indirect defenses, such as volatile compounds and extra floral nectaries (EFN), to attract canopy arthropods that are natural enemies of herbivorous organisms. While recent evidence suggests that upon perception of low red to far-red (R:FR) ratios, which signal the proximity of competitors, plants down-regulate resource allocation to direct chemical defenses, it is unknown if a similar phytochrome-mediated response occurs for indirect defenses. We evaluated the interactive effects of R:FR ratio and simulated herbivory on nectar production by EFNs of passion fruit (Passiflora edulis f. flavicarpa). The activity of petiolar EFNs dramatically increased in response to simulated herbivory and hormonal treatment with methyl jasmonate (MeJA). Low R:FR ratios, which induced a classic "shade-avoidance" repertoire of increased stem elongation in P. edulis, strongly suppressed the EFN response triggered by simulated herbivory or MeJA application. Strikingly, the EFN response to wounding and light quality was localized to the branches that received the treatments. In vines like P. edulis, a local response would allow the plants to precisely adjust their light harvesting and defense phenotypes to the local conditions encountered by individual branches when foraging for resources in patchy canopies. Consistent with the emerging paradigm that phytochrome regulation of jasmonate signaling is a central modulator of adaptive phenotypic plasticity, our results demonstrate that light quality is a strong regulator of indirect defenses.

Belowground Competition Directs Spatial Patterns of Seedling Growth in Boreal Pine Forests in Fennoscandia

Directory of Open Access Journals (Sweden)

E. Petter Axelsson

2014-09-01

Full Text Available Aboveground competition is often argued to be the main process determining patterns of natural forest regeneration. However, the theory of multiple resource limitation suggests that seedling performance also depends on belowground competition and, thus, that their relative influence is of fundamental importance. Two approaches were used to address the relative importance of above- and below-ground competition on regeneration in a nutrient-poor pine (Pinus sylvestris boreal forest. Firstly, seedling establishment beneath trees stem-girdled 12 years ago show that a substantial proportion of the seedlings were established within two years after girdling, which corresponds to a time when nutrient uptake by tree roots was severely reduced without disrupting water transport to the tree canopy, which consequently was maintained. The establishment during these two years also corresponds to abundances high enough for normal stand replacement. Secondly, surveys of regeneration within forest gaps showed that surrounding forests depressed seedlings, so that satisfactory growth occurred only more than 5 m from forest edges and that higher solar radiation in south facing edges was not enough to mediate these effects. We conclude that disruption of belowground competitive interactions mediates regeneration and, thus, that belowground competition has a strong limiting influence on seedling establishment in these forests.

Direct and indirect effects of light pollution on the performance of an herbivorous insect.

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Grenis, Kylee; Murphy, Shannon M

2018-02-09

Light pollution is a global disturbance with resounding impacts on a wide variety of organisms, but our understanding of these impacts is restricted to relatively few higher vertebrate species. We tested the direct effects of light pollution on herbivore performance as well as indirect effects mediated by host plant quality. We found that artificial light from streetlights alters plant toughness. Additionally, we found evidence of both direct and indirect effects of light pollution on the performance of an herbivorous insect, which indicates that streetlights can have cascading impacts on multiple trophic levels. Our novel findings suggest that light pollution can alter plant-insect interactions and thus may have important community-wide consequences. © 2018 Institute of Zoology, Chinese Academy of Sciences.

Municipal Competition for Inhabitants under Population Decrease. Zusammenfassung: Kommunale Konkurrenz um Einwohner bei Bevölkerungsrückgang

Directory of Open Access Journals (Sweden)

Peter Friedrich

2014-12-01

Full Text Available The shrinking population during the break-down, adaptation and recovery phase in Estonian social and political development enforces municipal competition among the municipalities. Competition for inhabitants is embedded in regional competition showing horizontal and vertical competition relations. Inhabitants’ competition prevails indirectly through municipal business promotion competition and directly through competition for inhabitants. The competition shows three phases. A phase concerns zoning and long-term planning; a second one refers to negotiations with settlement firms and short-term actions to attract inhabitants followed by a phase of revisions of zoning and measures. The oligopolistic industrial zoning model of business promotion policy points to the consequences of horizontal municipal competition also on population. Vertical influences on business promotion policy demonstrate a game-theoretic example of intergovernmental intervention from higher government on zoning. The negotiation phase in business promotion policy is modelled by a bilateral monopoly model between a municipality and a settlement firm. Horizontal regional competition highlights the implications on inhabitants’ competition. An oligopoly model of direct inhabitant competition concerns the zoning in particular for housing. Furthermore, a model of public enterprise service and fee formation and of horizontal public firm competition shows inhabitants’ competition in the second phase. Forms of inhabitant competition concerning suburbanisation and using public debt, revenues such as taxes, fees and expenditures are mentioned. Finally, follows a discussion of possible instruments to regulate inhabitant competition.

Assessing moderated mediation in linear models requires fewer confounding assumptions than assessing mediation.

Science.gov (United States)

Loeys, Tom; Talloen, Wouter; Goubert, Liesbet; Moerkerke, Beatrijs; Vansteelandt, Stijn

2016-11-01

It is well known from the mediation analysis literature that the identification of direct and indirect effects relies on strong no unmeasured confounding assumptions of no unmeasured confounding. Even in randomized studies the mediator may still be correlated with unobserved prognostic variables that affect the outcome, in which case the mediator's role in the causal process may not be inferred without bias. In the behavioural and social science literature very little attention has been given so far to the causal assumptions required for moderated mediation analysis. In this paper we focus on the index for moderated mediation, which measures by how much the mediated effect is larger or smaller for varying levels of the moderator. We show that in linear models this index can be estimated without bias in the presence of unmeasured common causes of the moderator, mediator and outcome under certain conditions. Importantly, one can thus use the test for moderated mediation to support evidence for mediation under less stringent confounding conditions. We illustrate our findings with data from a randomized experiment assessing the impact of being primed with social deception upon observer responses to others' pain, and from an observational study of individuals who ended a romantic relationship assessing the effect of attachment anxiety during the relationship on mental distress 2 years after the break-up. © 2016 The British Psychological Society.

Procrastination and suicide proneness: A moderated-mediation model for cognitive schemas and gender.

Science.gov (United States)

Klibert, Jeffrey; LeLeux-LaBarge, Kayla; Tarantino, Nicholas; Yancey, Thresa; Lamis, Dorian A

2016-07-01

This study examined the direct and indirect paths between procrastination and suicide proneness while considering gender differences. Participants included 547 undergraduates from a southeastern university. Procrastination was positively related to suicide proneness for both genders, although this relation was stronger for women. Moderated-mediation analyses with bootstrapping highlighted insufficient self-control schemas as a mediator in the relation between procrastination and suicide proneness. However, indirect pathways did not vary by gender. Results represent an extension of the Procrastination-Health Model by highlighting the contribution of cognitive factors in explaining the relation between procrastination and suicide proneness.

The effects of training and competition on achievement goals, motivational responses, and performance in a golf-putting task

NARCIS (Netherlands)

Pol, P.K.C. van de; Kavussanu, M.; Ring, C.

2012-01-01

This study examined whether (a) training and competition influence achievement goals, effort, enjoyment, tension, and performance; (b) achievement goals mediate the effects of training and competition on effort, enjoyment, tension, and performance; and (c) the context influences the relationships

Underground friends or enemies: model plants help to unravel direct and indirect effects of arbuscular mycorrhizal fungi on plant competition.

Science.gov (United States)

Facelli, Evelina; Smith, Sally E; Facelli, José M; Christophersen, Helle M; Andrew Smith, F

2010-03-01

*We studied the effects of two arbuscular mycorrhizal (AM) fungi, singly or together, on the outcome of competition between a host (tomato cultivar, wild-type (WT)) and a surrogate nonhost (rmc, a mycorrhiza-defective mutant of WT) as influenced by the contributions of the direct and AM phosphorus (P) uptake pathways to plant P. *We grew plants singly or in pairs of the same or different genotypes (inoculated or not) in pots containing a small compartment with (32)P-labelled soil accessible to AM fungal hyphae and determined expression of orthophosphate (P(i)) transporter genes involved in both AM and direct P uptake. *Gigaspora margarita increased WT competitive effects on rmc. WT and rmc inoculated with Glomus intraradices both showed growth depressions, which were mitigated when G. margarita was present. Orthophosphate transporter gene expression and (32)P transfer showed that the AM pathway operated in single inoculated WT, but not in rmc. *Effects of AM fungi on plant competition depended on the relative contributions of AM and direct pathways of P uptake. Glomus intraradices reduced the efficiency of direct uptake in both WT and rmc. The two-fungus combination showed that interactions between fungi are important in determining outcomes of plant competition.

Mechanisms and mediation in survival analysis: towards an integrated analytical framework

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Jonathan Pratschke

2016-02-01

Full Text Available Abstract Background A wide-ranging debate has taken place in recent years on mediation analysis and causal modelling, raising profound theoretical, philosophical and methodological questions. The authors build on the results of these discussions to work towards an integrated approach to the analysis of research questions that situate survival outcomes in relation to complex causal pathways with multiple mediators. The background to this contribution is the increasingly urgent need for policy-relevant research on the nature of inequalities in health and healthcare. Methods The authors begin by summarising debates on causal inference, mediated effects and statistical models, showing that these three strands of research have powerful synergies. They review a range of approaches which seek to extend existing survival models to obtain valid estimates of mediation effects. They then argue for an alternative strategy, which involves integrating survival outcomes within Structural Equation Models via the discrete-time survival model. This approach can provide an integrated framework for studying mediation effects in relation to survival outcomes, an issue of great relevance in applied health research. The authors provide an example of how these techniques can be used to explore whether the social class position of patients has a significant indirect effect on the hazard of death from colon cancer. Results The results suggest that the indirect effects of social class on survival are substantial and negative (-0.23 overall. In addition to the substantial direct effect of this variable (-0.60, its indirect effects account for more than one quarter of the total effect. The two main pathways for this indirect effect, via emergency admission (-0.12, on the one hand, and hospital caseload, on the other, (-0.10 are of similar size. Conclusions The discrete-time survival model provides an attractive way of integrating time-to-event data within the field of

Mechanisms and mediation in survival analysis: towards an integrated analytical framework.

Science.gov (United States)

Pratschke, Jonathan; Haase, Trutz; Comber, Harry; Sharp, Linda; de Camargo Cancela, Marianna; Johnson, Howard

2016-02-29

A wide-ranging debate has taken place in recent years on mediation analysis and causal modelling, raising profound theoretical, philosophical and methodological questions. The authors build on the results of these discussions to work towards an integrated approach to the analysis of research questions that situate survival outcomes in relation to complex causal pathways with multiple mediators. The background to this contribution is the increasingly urgent need for policy-relevant research on the nature of inequalities in health and healthcare. The authors begin by summarising debates on causal inference, mediated effects and statistical models, showing that these three strands of research have powerful synergies. They review a range of approaches which seek to extend existing survival models to obtain valid estimates of mediation effects. They then argue for an alternative strategy, which involves integrating survival outcomes within Structural Equation Models via the discrete-time survival model. This approach can provide an integrated framework for studying mediation effects in relation to survival outcomes, an issue of great relevance in applied health research. The authors provide an example of how these techniques can be used to explore whether the social class position of patients has a significant indirect effect on the hazard of death from colon cancer. The results suggest that the indirect effects of social class on survival are substantial and negative (-0.23 overall). In addition to the substantial direct effect of this variable (-0.60), its indirect effects account for more than one quarter of the total effect. The two main pathways for this indirect effect, via emergency admission (-0.12), on the one hand, and hospital caseload, on the other, (-0.10) are of similar size. The discrete-time survival model provides an attractive way of integrating time-to-event data within the field of Structural Equation Modelling. The authors demonstrate the efficacy

Prospects for indirect detection of frozen-in dark matter

Science.gov (United States)

Heikinheimo, Matti; Tenkanen, Tommi; Tuominen, Kimmo

2018-03-01

We study observational consequences arising from dark matter (DM) of nonthermal origin, produced by dark freeze-out from a hidden sector heat bath. We assume this heat bath was populated by feebly coupled mediator particles, produced via a Higgs portal interaction with the Standard Model (SM). The dark sector then attained internal equilibrium with a characteristic temperature different from the SM photon temperature. We find that even if the coupling between the DM and the SM sectors is very weak, the scenario allows for indirect observational signals. We show how the expected strength of these signals depends on the temperature of the hidden sector at DM freeze-out.

Role of indirect radiation effects on cell membranes in the immune response

International Nuclear Information System (INIS)

Sternglass, E.J.

1976-01-01

Recent work by Petkau indicates that, in sharp contrast to the case of damage to the genes, the doubling dose for indirect radiation damage to cell membranes decreases as the dose rate declines, apparently as the result of a free-radical-mediated oxidative reaction involving O 2 - . These findings explain the earlier results of Stokke, who observed significant declines in bone-marrow cellularity of the hematopoietic stem cells involved in the immune processes at dose rates below 10 -4 rad/min for total doses of only 0.1 to 2000 mrads, the doubling dose declining with total dose administered over periods of 6 to 18 weeks in a manner similar to that observed by Petkau. These observations, furthermore, explain the fact that erythrocyte permeability to monovalent cations can be significantly increased in occupationally exposed individuals at total doses of only 10 to 30 mR in 1 month, whereas thousands of rads are required at therapeutic dose rates. Evidence is presented suggesting the dominance of indirect, free-radical-mediated radiation effects over direct somatic mutation effects at background radiation rates on the development of cancer, leukemia, and infectious diseases from small radiation exposures encountered in the environment. The implications or the relative biological effect on the immune system of radiation at high and low dose rates are discussed

Peer Support and Adolescents' Physical Activity: The Mediating Roles of Self-Efficacy and Enjoyment.

Science.gov (United States)

Chen, Han; Sun, Haichun; Dai, Jun

2017-06-01

The present study aimed to contrast the mediating magnitude of self-efficacy and enjoyment connecting peer support and adolescents' physical activity (PA). Participants were 9th-12th grade students ( N  = 409; 56.5% boys) who were randomly chosen from six public schools located in Fuzhou city in southeast China. The bootstrapping method in structural equation modeling was conducted to examine the direct and indirect effects of peer support on adolescents' PA. Peer support did not directly impact PA. Rather, peer support indirectly influenced PA through either self-efficacy or enjoyment, with self-efficacy demonstrating a stronger mediating effect. Additionally, we found a significant serial mediating effect with enjoyment, and self-efficacy sequentially mediated the relationship between peer support and PA. The findings highlight the role of self-efficacy and enjoyment as mediators connecting peer support and PA. Self-efficacy seems to be more important, as it demonstrated a significantly greater mediating effect. © The Author 2017. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Air network performance and hub competitive position: evaluation of primary airports in East and South-East Asia

NARCIS (Netherlands)

Burghouwt, G.; de Wit, J.; Veldhuis, J.; Matsumoto, H.

2009-01-01

The growth of hub-and-spoke operations has changed the structure of competition among airlines and airports, meaning that airlines now compete both directly (air services from A to B) as well as indirectly (services from A to B via H). Traditional measures of airport performance, such as passenger

Effects of confidence and anxiety on flow state in competition.

Science.gov (United States)

Koehn, Stefan

2013-01-01

Confidence and anxiety are important variables that underlie the experience of flow in sport. Specifically, research has indicated that confidence displays a positive relationship and anxiety a negative relationship with flow. The aim of this study was to assess potential direct and indirect effects of confidence and anxiety dimensions on flow state in tennis competition. A sample of 59 junior tennis players completed measures of Competitive State Anxiety Inventory-2d and Flow State Scale-2. Following predictive analysis, results showed significant positive correlations between confidence (intensity and direction) and anxiety symptoms (only directional perceptions) with flow state. Standard multiple regression analysis indicated confidence as the only significant predictor of flow. The results confirmed a protective function of confidence against debilitating anxiety interpretations, but there were no significant interaction effects between confidence and anxiety on flow state.

Indirect taxation in the European Union

OpenAIRE

Ene, Sebastian; Micuda, Dan

2007-01-01

Indirect taxes are levied on the production and consumption of goods and services. They influence the retail price, and hence affect patterns of trade and consumption. Indirect taxes are ultimately paid by the final consumer. Sales and turnover taxes, excise duties and tariffs are the basic indirect taxes. In contrast with direct taxes, indirect taxes are seldom progressive. The principles for the levying of these taxes will be considered before the analysis of indirect taxes.

Achievement goals and emotions: The mediational roles of perceived progress, control, and value.

Science.gov (United States)

Hall, Nathan C; Sampasivam, Lavanya; Muis, Krista R; Ranellucci, John

2016-06-01

The link between achievement goals and achievement emotions is well established; however, research exploring potential mediators of this relationship is lacking. The control-value theory of achievement emotions (Pekrun, 2006, Educational Psychology Review, 18, 315) posits that perceptions of control and value mediate the relationship between achievement goals and achievement emotions, whereas the bidirectional theory of affect (Linnenbrink & Pintrich, 2002, Educational Psychologist, 37, 69) proposes that perceived progress mediates this relationship. The present study empirically evaluated three hypothesized mediators of the effects of achievement goals on learning-related emotions as proposed in the control-value theory and the bidirectional theory of affect. Undergraduate students (N = 273) from humanities, social science, and STEM disciplines participated. Participants completed web-based questionnaires evaluating academic achievement goals, perceptions of control, perceived task value, and achievement emotions. Results provided empirical support primarily for perceived progress as a mediator of mastery-approach goal effects on positive emotions (enjoyment, hope), showing indirect effects of mastery- and performance-approach goals on outcome-related emotions (hope, anxiety) via perceived control. Indirect effects of mastery- and performance-approach goals were further observed on anxiety via perceived value, with higher value levels predicting greater anxiety. Study findings partially support Linnenbrink and Pintrich's (2002, Educational Psychologist, 37, 69) bidirectional theory of affect while underscoring the potential for indirect effects of goals on emotions through perceived control as proposed by Pekrun (2006, Educational Psychology Review, 18, 315). © 2016 The British Psychological Society.

Lansoprazole Exacerbates Pemetrexed-Mediated Hematologic Toxicity by Competitive Inhibition of Renal Basolateral Human Organic Anion Transporter 3.

Science.gov (United States)

Ikemura, Kenji; Hamada, Yugo; Kaya, Chinatsu; Enokiya, Tomoyuki; Muraki, Yuichi; Nakahara, Hiroki; Fujimoto, Hajime; Kobayashi, Tetsu; Iwamoto, Takuya; Okuda, Masahiro

2016-10-01

Pemetrexed, a multitargeted antifolate, is eliminated by tubular secretion via human organic anion transporter 3 (hOAT3). Although proton pump inhibitors (PPIs) are frequently used in cancer patients, the drug interaction between PPIs and pemetrexed remains to be clarified. In this study, we examined the drug interaction between pemetrexed and PPIs in hOAT3-expressing cultured cells, and retrospectively analyzed the impact of PPIs on the development of hematologic toxicity in 108 patients who received pemetrexed and carboplatin treatment of nonsquamous non-small cell lung cancer for the first time between January 2011 and June 2015. We established that pemetrexed was transported via hOAT3 (Km = 68.3 ± 11.1 µM). Lansoprazole, rabeprazole, pantoprazole, esomeprazole, omeprazole, and vonoprazan inhibited hOAT3-mediated uptake of pemetrexed in a concentration-dependent manner. The inhibitory effect of lansoprazole was much greater than those of other PPIs and the apparent IC50 value of lansoprazole against pemetrexed transport via hOAT3 was 0.57 ± 0.17 µM. The inhibitory type of lansoprazole was competitive. In a retrospective study, multivariate analysis revealed that coadministration of lansoprazole, but not other PPIs, with pemetrexed and carboplatin was an independent risk factor significantly contributing to the development of hematologic toxicity (odds ratio: 10.004, P = 0.005). These findings demonstrated that coadministration of lansoprazole could exacerbate the hematologic toxicity associated with pemetrexed, at least in part, by competitive inhibition of hOAT3. Our results would aid clinicians to make decisions of coadministration drugs to avoid drug interaction-induced side effects for achievement of safe and appropriate chemotherapy with pemetrexed. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

Amygdaloid projections to the ventral striatum in mice: direct and indirect chemosensory inputs to the brain reward system.

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Novejarque, Amparo; Gutiérrez-Castellanos, Nicolás; Lanuza, Enrique; Martínez-García, Fernando

2011-01-01

Rodents constitute good models for studying the neural basis of sociosexual behavior. Recent findings in mice have revealed the molecular identity of the some pheromonal molecules triggering intersexual attraction. However, the neural pathways mediating this basic sociosexual behavior remain elusive. Since previous work indicates that the dopaminergic tegmento-striatal pathway is not involved in pheromone reward, the present report explores alternative pathways linking the vomeronasal system with the tegmento-striatal system (the limbic basal ganglia) by means of tract-tracing experiments studying direct and indirect projections from the chemosensory amygdala to the ventral striato-pallidum. Amygdaloid projections to the nucleus accumbens, olfactory tubercle, and adjoining structures are studied by analyzing the retrograde transport in the amygdala from dextran amine and fluorogold injections in the ventral striatum, as well as the anterograde labeling found in the ventral striato-pallidum after dextran amine injections in the amygdala. This combination of anterograde and retrograde tracing experiments reveals direct projections from the vomeronasal cortex to the ventral striato-pallidum, as well as indirect projections through different nuclei of the basolateral amygdala. Direct projections innervate mainly the olfactory tubercle and the islands of Calleja, whereas indirect projections are more widespread and reach the same structures and the shell and core of nucleus accumbens. These pathways are likely to mediate innate responses to pheromones (direct projections) and conditioned responses to associated chemosensory and non-chemosensory stimuli (indirect projections). Comparative studies indicate that similar connections are present in all the studied amniote vertebrates and might constitute the basic circuitry for emotional responses to conspecifics in most vertebrates, including humans.

Coping mediates the influence of personality on life satisfaction in patients with rheumatic diseases.

Science.gov (United States)

Vollmann, Manja; Pukrop, Jörg; Salewski, Christel

2016-04-01

A rheumatic disease can severely impair a person's quality of life. The degree of impairment, however, is not closely related to objective indicators of disease severity. This study investigated the influence and the interplay of core psychological factors, i.e., personality and coping, on life satisfaction in patients with rheumatic diseases. Particularly, it was tested whether coping mediates the effects of personality on life satisfaction. In a cross-sectional design, 158 patients diagnosed with a rheumatic disease completed questionnaires assessing the Big 5 personality traits (BFI-10), several disease-related coping strategies (EFK) and life satisfaction (HSWBS). Data were analyzed using a complex multiple mediation analysis with the Big 5 personality traits as predictors, coping strategies as mediators and life satisfaction as outcome. All personality traits and seven of the nine coping strategies were associated with life satisfaction (rs > |0.16|, ps ≤ 0.05). The mediation analysis revealed that personality traits had no direct, but rather indirect effects on life satisfaction through coping. Neuroticism had a negative indirect effect on life satisfaction through less active problem solving and more depressive coping (indirect effects > -0.03, ps  0.06, ps rheumatic diseases. The interplay of these variables should be considered in psychological interventions for patients with rheumatic diseases.

CURRENT TRENDS IN TAX HARMONIZATION AND COMPETITION WITHIN THE EUROPEAN UNION

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Gherman Adela-Teodora

2010-12-01

Full Text Available This article treats on the fiscal harmonization process within the European Union being indispensable for assuring loyalty in the competition on its single market, given the fact that different system of taxation had direct and powerful impact on the prices level and on chosing the location for production and distribution activities. Both direct and indirect taxation distort the four fundamental freedoms of the single market. Most of the European Unions regulations regarding fiscal harmonization resemble to the Directive regarding especially the indirect taxes: VAT, Excises. The fiscal reforms from the member states have to be conceived in such a manner that they take into account the necessity of fiscal harmonization on EU level, creating a reasonable compromise between each country's sovereignty and the desideratum of removing fiscal barriers from the normal functioning of the single market.

A computational description of simple mediation analysis

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Caron, Pier-Olivier

2018-04-01

Full Text Available Simple mediation analysis is an increasingly popular statistical analysis in psychology and in other social sciences. However, there is very few detailed account of the computations within the model. Articles are more often focusing on explaining mediation analysis conceptually rather than mathematically. Thus, the purpose of the current paper is to introduce the computational modelling within simple mediation analysis accompanied with examples with R. Firstly, mediation analysis will be described. Then, the method to simulate data in R (with standardized coefficients will be presented. Finally, the bootstrap method, the Sobel test and the Baron and Kenny test all used to evaluate mediation (i.e., indirect effect will be developed. The R code to implement the computation presented is offered as well as a script to carry a power analysis and a complete example.

Fitness, Sleep-Disordered Breathing, Symptoms of Depression, and Cognition in Inactive Overweight Children: Mediation Models.

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Stojek, Monika M K; Montoya, Amanda K; Drescher, Christopher F; Newberry, Andrew; Sultan, Zain; Williams, Celestine F; Pollock, Norman K; Davis, Catherine L

We used mediation models to examine the mechanisms underlying the relationships among physical fitness, sleep-disordered breathing (SDB), symptoms of depression, and cognitive functioning. We conducted a cross-sectional secondary analysis of the cohorts involved in the 2003-2006 project PLAY (a trial of the effects of aerobic exercise on health and cognition) and the 2008-2011 SMART study (a trial of the effects of exercise on cognition). A total of 397 inactive overweight children aged 7-11 received a fitness test, standardized cognitive test (Cognitive Assessment System, yielding Planning, Attention, Simultaneous, Successive, and Full Scale scores), and depression questionnaire. Parents completed a Pediatric Sleep Questionnaire. We used bootstrapped mediation analyses to test whether SDB mediated the relationship between fitness and depression and whether SDB and depression mediated the relationship between fitness and cognition. Fitness was negatively associated with depression ( B = -0.041; 95% CI, -0.06 to -0.02) and SDB ( B = -0.005; 95% CI, -0.01 to -0.001). SDB was positively associated with depression ( B = 0.99; 95% CI, 0.32 to 1.67) after controlling for fitness. The relationship between fitness and depression was mediated by SDB (indirect effect = -0.005; 95% CI, -0.01 to -0.0004). The relationship between fitness and the attention component of cognition was independently mediated by SDB (indirect effect = 0.058; 95% CI, 0.004 to 0.13) and depression (indirect effect = -0.071; 95% CI, -0.01 to -0.17). SDB mediates the relationship between fitness and depression, and SDB and depression separately mediate the relationship between fitness and the attention component of cognition.

New Models for Value Creation and Competitive Advantage in the Petroleum Industry

OpenAIRE

Stabell, Charles

2001-01-01

This research project has applied, tested and further developed a set of new models for the analysis of value creation and competitive advantage in the context of the global petroleum industry. The basic idea behind the project was that Porter’s value chain model (1985) for the analysis of firm-level competitive advantage was basically only applicable to manufacturing. Building on Thompson’s (1967) distinction between long-linked, intensive and mediating value creation technologies, we propos...

Mediator Variables in Headache Research: Methodological Critique and Exemplar Using Self-Efficacy as a Mediator of the Relationship Between Headache Severity and Disability.

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Peck, Kelly R; Smitherman, Todd A

2015-09-01

Despite advances in headache medicine, there remains little research on process-related variables that mediate relations between headache and outcomes, as well as limited dissemination of optimal statistical methodology for conducting mediation analyses. The present paper thus aims to promote and demonstrate a contemporary approach to mediation analysis as applied to headache. An overview of a contemporary path-analytic approach to mediation analysis is presented, with an empirical exemplar for illustrative purposes. In the exemplar, headache management self-efficacy (HMSE) was proposed as a mediator between headache severity and disability. The sample included 907 young adults (M age = 19.03 [SD = 2.26]; 70.8% female) with primary headache. Direct and indirect effects of headache severity on headache disability through HMSE were assessed using the espoused methods. Pain severity was positively associated with headache disability (β = 2.91, 95% confidence interval [CI; 2.62, 3.19]) and negatively associated with HMSE (β = -3.50, 95% CI [-4.24, -2.76]); HMSE was negatively associated with headache disability (β = 0.07, 95% CI [-0.09, -0.04]). A positive indirect effect of pain severity on disability through HMSE was identified (point estimate = 0.24, 95% CI [0.14, 0.34]); thus, self-efficacy mediated the association between pain severity and disability. The proposed mediation model accounted for 38% of total variance in disability (P headache literature. In one exemplar application, self-efficacy partially accounted for the disability resulting from headache. We advocate for increased attention to intervening variables in headache via dissemination of contemporary mediation analyses. © 2015 American Headache Society.

Impact of Interference Competition on Exploration and Food Exploitation in the Ant Lasius niger

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Vincent Fourcassié

2012-01-01

Full Text Available Competition acts as a major force in shaping spatially and/or temporally the foraging activity of ant colonies. Interference competition between colonies in particular is widespread in ants where it can prevent the physical access of competitors to a resource, either directly by fighting or indirectly, by segregating the colony foraging areas. Although the consequences of interference competition on ant distribution have been well studied in the literature, the behavioral mechanisms underlying interference competition have been less explored. Little is known on how ants modify their exploration patterns or the choice of a feeding place after experiencing aggressive encounters. In this paper, we show that, at the individual level, the aphid-tending ant Lasius niger reacts to the presence of an alien conspecific through direct aggressive behavior and local recruitment in the vicinity of fights. At the colony level, however, no defensive recruitment is triggered and the “risky” area where aggressive encounters occur is not specifically avoided during further exploration or food exploitation. We discuss how between-species differences in sensitivity to interference competition could be related to the spatial and temporal predictability of food resources at stake.

ICT as a new competitive advantage factor – case of small transitional hotel sector

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Tanja Mihalic

2013-03-01

Full Text Available This paper studies the information and communication technology (ICT in a small hotel sector at a point in time when the transition towards a full market economy is coming to the end and competitiveness and ICT implementation is gaining on importance. Its main purpose is to study a business potential of this new competitive advantage resource and its productivity paradox. A competitive advantage factor model (CAF model has been proposed and the structural modelling (SEM has been performed on the case of a small transitional Slovenian hotel sector. The study contributes to knowledge on ICT competiveness and ICT productivity paradox in hotel sector. Further, its results hold practical implications for the strategy for hotels operating in small-sized hotel industries in transitional or ICT developing environments. In more concrete terms, research findings indicate that such hotel sectors need to speed the ICT implementation. ICT as such doesn’t directly increase the firm’s profitability, yet there is an indirect positive impact of factor ICT on a firm’s financial performance that emerges through other competitiveness factors, such as differentiation, quality or image, which helps firms to stay competitive on the tourism markets.

Self-reported impulsivity, but not behavioral choice or response impulsivity, partially mediates the effect of stress on drinking behavior.

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Hamilton, Kristen R; Ansell, Emily B; Reynolds, Brady; Potenza, Marc N; Sinha, Rajita

2013-01-01

Stress and impulsivity contribute to alcohol use, and stress may also act via impulsivity to increase drinking behavior. Impulsivity represents a multi-faceted construct and self-report and behavioral assessments may effectively capture distinct clinically relevant factors. The present research investigated whether aspects of impulsivity mediate the effect of stress on alcohol use. A community-based sample of 192 men and women was assessed on measures of cumulative stress, alcohol use, self-reported impulsivity, and behavioral choice and response impulsivity. Data were analyzed using regression and bootstrapping techniques to estimate indirect effects of stress on drinking via impulsivity. Cumulative adversity exhibited both direct effects and indirect effects (via self-reported impulsivity) on drinking behavior. Additional models examining specific types of stress indicated direct and indirect effects of trauma and recent life events, and indirect effects of major life events and chronic stressors on drinking behavior. Overall, cumulative stress was associated with increased drinking behavior, and this effect was partially mediated by self-reported impulsivity. Self-reported impulsivity also mediated the effects of different types of stress on drinking behavior. These findings highlight the value of mediation models to examine the pathways through which different types of stress increase drinking behavior. Treatment and prevention strategies should focus on enhancing stress management and self-control.

Demolishing the competition: the longitudinal link between competitive video games, competitive gambling, and aggression.

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Adachi, Paul J C; Willoughby, Teena

2013-07-01

The majority of research on the link between video games and aggression has focused on the violent content in games. In contrast, recent experimental research suggests that it is video game competition, not violence, that has the greatest effect on aggression in the short-term. However, no researchers have examined the long-term relationship between video game competition and aggression. In addition, if competition in video games is a significant reason for the link between video game play and aggression, then other competitive activities, such as competitive gambling, also may predict aggression over time. In the current study, we directly assessed the socialization (competitive video game play and competitive gambling predicts aggression over time) versus selection hypotheses (aggression predicts competitive video game play and competitive gambling over time). Adolescents (N = 1,492, 50.8 % female) were surveyed annually from Grade 9 to Grade 12 about their video game play, gambling, and aggressive behaviors. Greater competitive video game play and competitive gambling predicted higher levels of aggression over time, after controlling for previous levels of aggression, supporting the socialization hypothesis. The selection hypothesis also was supported, as aggression predicted greater competitive video game play and competitive gambling over time, after controlling for previous competitive video game play and competitive gambling. Our findings, taken together with the fact that millions of adolescents play competitive video games every day and that competitive gambling may increase as adolescents transition into adulthood, highlight the need for a greater understanding of the relationship between competition and aggression.

Direct and indirect links between organizational work-home culture and employee well-being

OpenAIRE

Beauregard, T. Alexandra

2011-01-01

The extent to which an organization's culture exhibits support for its employees' efforts to balance work and personal responsibilities has been shown to influence a number of work- and home-related outcomes. This study tests a model with a mix of mediated and moderated relationships to investigate direct and indirect routes by which work-home culture may affect employee well-being. Sex differences in these relationships are also explored. Data collected from public sector employees in the UK...

Dynamical Messengers for Gauge Mediation

Energy Technology Data Exchange (ETDEWEB)

Hook, Anson; Torroba, Gonzalo; /SLAC /Stanford U., Phys. Dept.

2011-08-17

We construct models of indirect gauge mediation where the dynamics responsible for breaking supersymmetry simultaneously generates a weakly coupled subsector of messengers. This provides a microscopic realization of messenger gauge mediation where the messenger and hidden sector fields are unified into a single sector. The UV theory is SQCD with massless and massive quarks plus singlets, and at low energies it flows to a weakly coupled quiver gauge theory. One node provides the primary source of supersymmetry breaking, which is then transmitted to the node giving rise to the messenger fields. These models break R-symmetry spontaneously, produce realistic gaugino and sfermion masses, and give a heavy gravitino.

Community-based clinic volunteering: an evaluation of the direct and indirect effects on the experience of health science college students.

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Bird, Yelena; Islam, Adiba; Moraros, John

2016-01-18

The present study was conducted in a multi service-learning, student managed and operated, community-based clinic. Its aim was to measure the direct and indirect effects of how proximal factors (i.e., 'management', 'support received', 'duration of involvement', and 'average time spent per month') and mediators (i.e., 'training received', 'motivation', and 'commitment') influence distal outcomes (i.e., 'performance', 'satisfaction', and 'overall experience') within a volunteer organization. Participants were recruited through the use of an email list server. An online survey was used containing multi-item measures from validated scales. Data were collected from 170 volunteers from July to August 2013. Data analysis used a structural equation modeling (SEM) framework for the estimation of direct and indirect effects on constructs and variables of interest. Only statistically significant relationships were reported at p direct effects worthy of note. First, the proximal factor of 'management' plays an important role in influencing the mediators of 'motivation' (standardized beta = 0.55) and 'training received' (0.65) by the student volunteers but has a relatively small impact on their 'commitment' (0.39) to the organization. Second, the mediator of 'motivation' proved to have the strongest impact on the distal outcome of volunteer 'performance' and 'satisfaction' levels (0.41 and 0.58 respectively), whereas 'commitment' (0.44) was the key in determining their 'overall experience' with the organization. These results in turn, help contextualize the indirect effects observed in our study. Namely, the proximal factor of 'management' played a distinctive role in influencing the distal outcomes of volunteer 'performance' (0.32) and 'overall experience' (0.66), whereas the organizational 'support received' by the volunteers was key to their 'satisfaction' (0.21). The findings of the present study shed light into the direct and indirect effects of how proximal factors

Peer Rejection and Internalizing Behavior: The Mediating Role of Peer Victimization in Preschool.

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Metin Aslan, Özge

2018-05-23

The author examined the relationship among peer rejection, peer victimization, and internalizing behaviors. The author hypothesized that physical and relational victimization would have a different indirect effect on the relationship between peer rejection and internalizing behaviors. Participants were 94 preschool children (37 girls; average age 49.97 months) from two university preschools located in the northern part of the United States. The results indicated that internalizing behaviors predicted the mediating variables only regarding relational victimization. Relational victimization indirectly affected the association between peer rejection and internalizing behaviors. The study provides evidence of the mediating effect of victimization behaviors on the relationship among peer rejection, victimization, and internalizing behaviors.

Meeting the near-term demand for hydrogen using nuclear energy in competitive power markets

International Nuclear Information System (INIS)

Miller, A.I.; Duffey, R.B.

2004-01-01

Hydrogen is becoming the reference fuel for future transportation and the timetable for its adoption is shortening. However, to deploy its full potential, hydrogen production either directly or indirectly needs to satisfy three criteria: no associated emissions, including CO 2 ; wide availability; and affordability. This creates a window of great opportunity within the next 15 years for nuclear energy to provide the backbone of hydrogen-based energy systems. But nuclear must establish its hydrogen generating role long before the widespread deployment of Gen IV high-temperature reactors, with their possibility of producing hydrogen directly by heat rather than electricity. For Gen IV the major factors will be efficiency and economic cost, particularly if centralized storage is needed and/or credits for avoided emissions and/or oxygen sales. In the interim, despite its apparently lower overall efficiency, water electrolysis is the only available technology today able to meet the first and second criteria. The third criterion includes costs of electrolysis and electricity. The primary requirements for affordable electrolysis are low capital cost and high utilisation. Consequently, the electricity supply must enable high utilisation as well as being itself low-cost and emissions-free. Evolved Gen III+ nuclear technologies can produce electricity on large scales and at rates competitive with today's CO 2 -emitting, fossil-fuelled technologies. As an example of electrolytic hydrogen's potential, we show competitive deployment in a typical competitive power market. Among the attractions of this approach are reactors supplying a base-loaded market - though permitting occasional, opportunistic diversion of electricity during price spikes on the power grid - and easy delivery of hydrogen to widely distributed users. Gen IV systems with multiple product streams and higher efficiency (e.g., the SCWR) can also be envisaged which can use competitive energy markets to advantage

Causal mediation analysis with a binary outcome and multiple continuous or ordinal mediators: Simulations and application to an alcohol intervention.

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Nguyen, Trang Quynh; Webb-Vargas, Yenny; Koning, Ina M; Stuart, Elizabeth A

We investigate a method to estimate the combined effect of multiple continuous/ordinal mediators on a binary outcome: 1) fit a structural equation model with probit link for the outcome and identity/probit link for continuous/ordinal mediators, 2) predict potential outcome probabilities, and 3) compute natural direct and indirect effects. Step 2 involves rescaling the latent continuous variable underlying the outcome to address residual mediator variance/covariance. We evaluate the estimation of risk-difference- and risk-ratio-based effects (RDs, RRs) using the ML, WLSMV and Bayes estimators in Mplus. Across most variations in path-coefficient and mediator-residual-correlation signs and strengths, and confounding situations investigated, the method performs well with all estimators, but favors ML/WLSMV for RDs with continuous mediators, and Bayes for RRs with ordinal mediators. Bayes outperforms WLSMV/ML regardless of mediator type when estimating RRs with small potential outcome probabilities and in two other special cases. An adolescent alcohol prevention study is used for illustration.

Gratitude and suicidal ideation and suicide attempts among Chinese adolescents: direct, mediated, and moderated effects.

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Li, Dongping; Zhang, Wei; Li, Xian; Li, Nini; Ye, Baojuan

2012-02-01

In a sample of 1252 Chinese adolescents (mean age = 15.00 years), this study examined the direct relations between gratitude and adolescents' suicidal ideation and suicide attempts. This study also examined indirect relations between gratitude and suicidal ideation and suicide attempts via two self-system beliefs--coping efficacy and self-esteem. Finally, this study examined the extent to which stressful life events moderated the direct and indirect relations between gratitude and suicidal ideation and suicide attempts. The odds of suicidal ideation and suicide attempts were lower among adolescents who scored higher on gratitude, after controlling for demographic variables. Self-esteem mediated the relations between gratitude and suicidal ideation and suicide attempts, while the mediating role of coping efficacy was not significant. Moreover, stressful life events moderated the mediated path through self-esteem. This indirect effect was stronger for adolescents low on stressful life events than that for those high on stressful life events. This study discusses the theoretical and practical implications of these findings. Copyright © 2011 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Anxiety and burnout in young athletes: The mediating role of cognitive appraisal.

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Gomes, A R; Faria, S; Vilela, C

2017-12-01

This study tested the relationship between trait anxiety, cognitive appraisal, and athletes' burnout proposing two hypotheses: (a) there is a direct relationship between athletes' trait anxiety and cognitive appraisal and burnout, and (b) cognitive appraisal mediates the relationship between trait anxiety and burnout, and this mediation occurs despite the competitive level and sport records of athletes. The study included 673 young athletes and provided measures of trait anxiety, cognitive appraisal, and burnout. Structural equation modeling indicated that cognitive appraisal mediates the relationship between trait anxiety and burnout, confirming hypothesis 2, and this model provided better fit than the direct model of hypothesis 1. However, the mediation also indicated that the direct relationship between trait anxiety and burnout should be considered. The mediating model was invariant according to competitive levels and sport records. In conclusion, cognitive appraisal is an important variable in explaining athletes' burnout. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Fluctuating asymmetry, sociosexuality, and intrasexual competitive tactics.

Science.gov (United States)

Simpson, J A; Gangestad, S W; Christensen, P N; Leck, K

1999-01-01

Heterosexual men and women were told they were competing with another same-sex individual for a date with an attractive opposite-sex interviewer. After answering 6 questions, participants were asked to tell the competitor why the interviewer should choose them over the competitor. Participants' videotaped behavior was coded for different behavioral tactics. Men who were more symmetrical and who had a more unrestricted sociosexual orientation were more likely to use direct competition tactics than were less symmetrical and restricted men. Restricted men accentuated their positive personal qualities, presenting themselves as "nice guys." Structural equation modeling revealed that fluctuating asymmetry (FA) was directly associated with the use of direct competition tactics. However, the link between FA and presenting oneself as a nice guy was mediated through sociosexuality. No effects were found for women.

Indirect Self-Destructiveness and Emotional Intelligence.

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Tsirigotis, Konstantinos

2016-06-01

While emotional intelligence may have a favourable influence on the life and psychological and social functioning of the individual, indirect self-destructiveness exerts a rather negative influence. The aim of this study has been to explore possible relations between indirect self-destructiveness and emotional intelligence. A population of 260 individuals (130 females and 130 males) aged 20-30 (mean age of 24.5) was studied by using the Polish version of the chronic self-destructiveness scale and INTE, i.e., the Polish version of the assessing emotions scale. Indirect self-destructiveness has significant correlations with all variables of INTE (overall score, factor I, factor II), and these correlations are negative. The intensity of indirect self-destructiveness differentiates significantly the height of the emotional intelligence and vice versa: the height of the emotional intelligence differentiates significantly the intensity of indirect self-destructiveness. Indirect self-destructiveness has negative correlations with emotional intelligence as well as its components: the ability to recognize emotions and the ability to utilize emotions. The height of emotional intelligence differentiates the intensity of indirect self-destructiveness, and vice versa: the intensity of indirect self-destructiveness differentiates the height of emotional intelligence. It seems advisable to use emotional intelligence in the prophylactic and therapeutic work with persons with various types of disorders, especially with the syndrome of indirect self-destructiveness.

Instantaneous and cumulative influences of competition on impulsive choices in domestic chicks.

Directory of Open Access Journals (Sweden)

Hidetoshi eAmita

2011-09-01

Full Text Available This study examined instantaneous and cumulative effects of competitive interactions on impulsiveness in the inter-temporal choices in domestic chicks. Chicks were trained to peck colored beads to gain delayed food rewards (1 or 6 grains of millet delivered after a delay ranging between 0–4.5 s, and were tested in binary choices between a small-short delay option (SS and a large-long delay alternative (LL. To examine whether competitive foraging instantaneously changes impulsiveness, we intraindividually compared choices between two consecutive tests in different contexts, one with competitors and another without. We found that (1 the number of the choice of LL was not influenced by competition in the tests, but (2 the operant peck latency was shortened by competition, suggesting a socially enhanced incentive for food. To further examine the lasting changes, two groups of chicks were consecutively trained and tested daily for 2 weeks according to a behavioral titration procedure, one with competitors and another without. Inter-group comparisons of the choices revealed that (3 choice impulsiveness gradually decreased along development, while (4 the chicks trained in competition maintained a higher level of impulsiveness. These results suggest that competitive foraging causes impulsive choices not by direct/contextual modification. Causal link between the instantaneous enhancement of incentive and the gradual effects on impulsivity remains to be examined. Some (yet unspecified factors may be indirectly involved.

Positive perfectionism, negative perfectionism, and emotional eating: The mediating role of stress.

Science.gov (United States)

Wang, Hanwei; Li, Jie

2017-08-01

The current study examines the different impacts of positive perfectionism and negative perfectionism on individuals' emotional eating, as well as stress as the proposed underlying mediator that explains the abovementioned relationships. Overall, 386 adults in China reported their levels of positive perfectionism, negative perfectionism, perceived stress, and emotional eating behaviors. Results demonstrate that positive perfectionism is negatively associated with emotional eating, while negative perfectionism is positively associated with emotional eating. In addition, stress mediates the relationship between perfectionism and emotional eating. Specifically, positive perfectionism is indirectly related to emotional eating through the mediation of stress, whereas negative perfectionism is related to emotional eating directly and indirectly through the mediation of stress. Findings of the current study indicate that practitioners working with individuals who suffer from emotional eating problems should focus on ways to reduce negative perfectionism while finding approaches that enhance positive perfectionism. With this approach, individuals would experience less stress and, therefore, would be less likely to be involved in emotional eating. Copyright © 2017 Elsevier Ltd. All rights reserved.

Haloperidol Selectively Remodels Striatal Indirect Pathway Circuits

Science.gov (United States)

Sebel, Luke E; Graves, Steven M; Chan, C Savio; Surmeier, D James

2017-01-01

Typical antipsychotic drugs are widely thought to alleviate the positive symptoms of schizophrenia by antagonizing dopamine D2 receptors expressed by striatal spiny projection neurons (SPNs). What is less clear is why antipsychotics have a therapeutic latency of weeks. Using a combination of physiological and anatomical approaches in ex vivo brain slices from transgenic mice, it was found that 2 weeks of haloperidol treatment induced both intrinsic and synaptic adaptations specifically within indirect pathway SPNs (iSPNs). Perphenazine treatment had similar effects. Some of these adaptations were homeostatic, including a drop in intrinsic excitability and pruning of excitatory corticostriatal glutamatergic synapses. However, haloperidol treatment also led to strengthening of a subset of excitatory corticostriatal synapses. This slow remodeling of corticostriatal iSPN circuitry is likely to play a role in mediating the delayed therapeutic action of neuroleptics. PMID:27577602

The relationship between competitive anxiety, achievement goals, and motivational climates.

Science.gov (United States)

Ntoumanis, N; Biddle, S

1998-06-01

The purpose of this study was to examine the relationships of achievement goal orientations and perceived motivational climate to perceptions of the intensity and direction of competitive state anxiety in a sample of university athletes representing various team sports. Although some studies have demonstrated that task orientation and mastery climate are associated with adaptive emotional patterns and ego orientation and performance climate are linked to less adaptive emotions, others have not verified these findings. In the present study, structural equation modeling was used to test these links. The results showed that perceptions of a performance climate were associated with ego orientation, whereas perceptions of a mastery climate were linked to task orientation. Furthermore, no significant links were found between task orientation and direction of competitive anxiety, while it was shown that the impact of ego orientation on the intensity and direction of cognitive and somatic anxiety was exerted through self-confidence. No significant direct links were found between motivational climates and competitive anxiety, thus implying that motivational climates may have an indirect impact on affective responses through the different goal orientations. The findings of the present study are discussed along with suggestions for examining situational and individual difference variables that may explain the relationships between intensity and direction of competitive anxiety and achievement goals and motivational climates.

Species interactions and response time to climate change: ice-cover and terrestrial run-off shaping Arctic char and brown trout competitive asymmetries

Science.gov (United States)

Finstad, A. G.; Palm Helland, I.; Jonsson, B.; Forseth, T.; Foldvik, A.; Hessen, D. O.; Hendrichsen, D. K.; Berg, O. K.; Ulvan, E.; Ugedal, O.

2011-12-01

There has been a growing recognition that single species responses to climate change often mainly are driven by interaction with other organisms and single species studies therefore not are sufficient to recognize and project ecological climate change impacts. Here, we study how performance, relative abundance and the distribution of two common Arctic and sub-Arctic freshwater fishes (brown trout and Arctic char) are driven by competitive interactions. The interactions are modified both by direct climatic effects on temperature and ice-cover, and indirectly through climate forcing of terrestrial vegetation pattern and associated carbon and nutrient run-off. We first use laboratory studies to show that Arctic char, which is the world's most northernmost distributed freshwater fish, outperform trout under low light levels and also have comparable higher growth efficiency. Corresponding to this, a combination of time series and time-for-space analyses show that ice-cover duration and carbon and nutrient load mediated by catchment vegetation properties strongly affected the outcome of the competition and likely drive the species distribution pattern through competitive exclusion. In brief, while shorter ice-cover period and decreased carbon load favored brown trout, increased ice-cover period and increased carbon load favored Arctic char. Length of ice-covered period and export of allochthonous material from catchments are major, but contrasting, climatic drivers of competitive interaction between these two freshwater lake top-predators. While projected climate change lead to decreased ice-cover, corresponding increase in forest and shrub cover amplify carbon and nutrient run-off. Although a likely outcome of future Arctic and sub-arctic climate scenarios are retractions of the Arctic char distribution area caused by competitive exclusion, the main drivers will act on different time scales. While ice-cover will change instantaneously with increasing temperature

Perception of coaching behaviors, coping, and achievement in a sport competition.

Science.gov (United States)

Nicolas, Michel; Gaudreau, Patrick; Franche, Veronique

2011-06-01

This study examined the relationship between perceived coaching behaviors, coping strategies during a sport competition, and sport achievement. A prospective design was used in which 80 athletes from individual sports completed measures of perceived coaching behaviors two days before a competition (Time 1) and measures of coping and sport achievement within three hours after a sport competition (Time 2). As expected, results of multiple regressions indicated that supportive coaching was a positive predictor of task-oriented coping and sport achievement whereas unsupportive coaching was a positive predictor of disengagement-oriented coping. Both types of coping were significantly associated with sport achievement. Task-oriented coping was a significant partial mediator in the relation between supportive coaching and sport achievement. This study, which contributes to both the coaching and coping literatures, highlights the role of supportive coaching behaviors in the initiation of effective stress management during sport competitions.

Mediating the distal crime-drug relationship with proximal reactive criminal thinking.

Science.gov (United States)

Walters, Glenn D

2016-02-01

This article describes the results of a study designed to test whether reactive criminal thinking (RCT) does a better job of mediating the crime → drug relationship than it does mediating the drug → crime relationship after the direct effects of crime on drug use/dependency and of drug use/dependency on crime have been rendered nonsignificant by control variables. All 1,170 male members of the Pathways to Desistance study (Mulvey, 2012) served as participants in the current investigation. As predicted, the total (unmediated) effects of crime on substance use/dependence and of substance use/dependence on crime were nonsignificant when key demographic and third variables were controlled, although the indirect (RCT-mediated) effect of crime on drug use was significant. Proactive criminal thinking (PCT), by comparison, failed to mediate either relationship. The RCT continued to mediate the crime → drug relationship and the PCT continued to not mediate either relationship when more specific forms of offending (aggressive, income) and substance use/dependence (drug use, substance-use dependency symptoms) were analyzed. This offers preliminary support for the notion that even when the total crime-drug effect is nonsignificant the indirect path from crime to reactive criminal thinking to drugs can still be significant. Based on these results, it is concluded that mediation by proximal reactive criminal thinking is a mechanism by which distal measures of crime and drug use/dependence are connected. (c) 2016 APA, all rights reserved).

The relation between proactive environmental strategies and competitive advantage

Science.gov (United States)

Butnariu, A.; Avasilcăi, S.

2015-11-01

There are two distinct orientations of the environmental management that companies may adopt: the model of compliance and the strategic model. The strategic model treats environmental expenses as investments that will lead to competitive advantage for the company. Nevertheless, there are few scientific works that prove the relation between corporate environmental investments and competitive advantage. Thereby, in order to bring clarifications about the profound implications of environmental investments, in the first stage of our research we have proposed the hypothesis that the environmental investments would probably lead to competitive advantage by creating capabilities that are mediators of this relation. In the second stage we have tested this hypothesis, using the research method of survey. A questionnaire was sent to managers in textile Romanian industry, and 109 answers were received. The data was analysed using the linear multiple regression method and the results confirm our hypothesis.

Adolescent egocentrism and indoor tanning: is the relationship direct or mediated?

Science.gov (United States)

Banerjee, Smita C.; Greene, Kathryn; Yanovitzky, Itzhak; Bagdasarov, Zhanna; Choi, Soe Yoon; Magsamen-Conrad, Kate

2016-01-01

This paper explored how imaginary audience and personal fable ideations contribute to adolescent indoor tanning intentions directly and indirectly through the way they shape pro-tanning attitude and association with peers who use tanning beds. Five hundred and ninety-five male (n = 207) and female (n = 387) adolescents, ranging in age from 11 to 19 (M = 16.87; SD = 1.34) years completed a cross-sectional survey. Measures included imaginary audience, personal fable (three dimensions: invulnerability, uniqueness, and omnipotence), pro-tanning attitude, association with peers who use tanning beds, and tanning bed use intentions. Bootstrapping analyses documented that imaginary audience ideations are indirectly associated with indoor tanning intentions through the mediation of pro-tanning attitude and association with peers who use tanning beds. Of the personal fable ideations, only invulnerability ideation is indirectly associated with indoor tanning intentions through the mediation of association with peers who use tanning beds. Design and evaluation of interventions and campaigns to reduce indoor tanning must be targeted to adolescents varying in imaginary audience ideations differently. PMID:28042281

Psychological Vulnerability and Problem Gambling: The Mediational Role of Cognitive Distortions.

Science.gov (United States)

Lévesque, David; Sévigny, Serge; Giroux, Isabelle; Jacques, Christian

2018-01-03

Despite numerous studies demonstrating the influence of cognitive distortions on gambling problem severity, empirical data regarding the role of psychological vulnerability on the latter is limited. Hence, this study assesses the mediating effect of cognitive distortions between psychological vulnerability (personality and mood), and gambling problem severity. It also verifies whether the relationships between these variables differs according to the preferred gambling activity. The sample is composed of 272 male gamblers [191 poker players; 81 video lottery terminal (VLT) players] aged between 18 and 82 years (M = 35.2). Bootstrap analysis results revealed that cognitive distortions mediate the effect of narcissism on gambling problem severity for both groups. The level of depression for VLT players significantly predicted gambling problem severity, both directly and indirectly via the mediating effect of cognitive distortions. Mediation analyses also indicated that narcissism had an indirect impact on problem gambling through cognitive distortions for both groups. These findings suggest that certain vulnerabilities related to personality and mood may influence cognitive distortion intensity and gambling problem severity. In addition, psychological vulnerabilities could differ based on preferred gambling activity. These results may be useful for prevention policies, identifying high risk gamblers and planning psychological interventions.

Obesity Suppresses Cell-Competition-Mediated Apical Elimination of RasV12-Transformed Cells from Epithelial Tissues.

Science.gov (United States)

Sasaki, Ayana; Nagatake, Takahiro; Egami, Riku; Gu, Guoqiang; Takigawa, Ichigaku; Ikeda, Wataru; Nakatani, Tomoya; Kunisawa, Jun; Fujita, Yasuyuki

2018-04-24

Recent studies have revealed that newly emerging transformed cells are often eliminated from epithelial tissues via cell competition with the surrounding normal epithelial cells. This cancer preventive phenomenon is termed epithelial defense against cancer (EDAC). However, it remains largely unknown whether and how EDAC is diminished during carcinogenesis. In this study, using a cell competition mouse model, we show that high-fat diet (HFD) feeding substantially attenuates the frequency of apical elimination of RasV12-transformed cells from intestinal and pancreatic epithelia. This process involves both lipid metabolism and chronic inflammation. Furthermore, aspirin treatment significantly facilitates eradication of transformed cells from the epithelial tissues in HFD-fed mice. Thus, our work demonstrates that obesity can profoundly influence competitive interaction between normal and transformed cells, providing insights into cell competition and cancer preventive medicine. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

FISCAL COMPETITION AND DIRECT FOREIGN INVESTMENTS: ROMANIA VERSUS POLAND

Directory of Open Access Journals (Sweden)

Lazar Paula

2012-12-01

Full Text Available The European Economic Community treaty defines indirect taxation common rules taking into consideration their impact upon free merchandise’s circulation and upon international commercial exchanges. Once the Roma treaty has been signed (1957 the established scope was creating a common market. But, how is it possible to create a common market without any monetary and fiscal instruments? Thus, these instruments have had to be created in order to achieve such an objective. If from the monetary point of view introducing euro as a common currency was a big step ahead, from the fiscal point of view things haven’t evolved in such an easy manner. Fiscal objectives are achieved only if the national market is running normally and correctly. Indirect taxation is harmonized base upon article 113 from the European Union Treaty, while regarding direct taxation legal recommendations and regulations approval we can’t talk about harmonization but about fiscal competition. We are stating this because there are 27 states in the European Union and each one is sustaining its own direct taxation system. Furthermore, the taxation system (fiscal system is influencing member states economical performances through economies, investments and human capital formation by affecting the revenue’s distribution, research and development expenses level and type and by fiscal competition – an effect more and more profound. In this context we aim at analyzing the way fiscal competition had had a positive impact upon attracting foreign direct investments in Romania and Poland. We also aim at underlining positive and negative points for fiscal competition taking into consideration that not only a decrease in micro or macro-economic fiscal burden will have a positive impact upon investments in-flows and there are other factors to be taken into consideration, like: infrastructure, labor expenses

Ethanol extracts of saw palmetto contain the indirectly acting sympathomimetic: tyramine.

Science.gov (United States)

Chua, Thiam; Simpson, Jamie S; Ventura, Sabatino

2011-01-01

To identify the bioactive components of saw palmetto ethanol extracts that affect contractility in the rat prostate gland. A commercially available saw palmetto ethanol extract was lyophilized then subjected to fractionation using silica gel column chromatography. Composition of fractions was assessed by proton nuclear magnetic resonance ((1)H NMR) spectroscopy and mass spectrometry (MS). Contractile activity of these fractions was evaluated pharmacologically using isolated preparations of rat prostate gland and compared to the activity of crude ethanol extract. Saw palmetto ethanol extract caused contractions of the rat prostate gland which were consistent with indirectly acting sympathomimetic activity. Fractions resulting from chromatography produced contractions of isolated rat prostates that were similar in magnitude to the contractions produced by the crude extracts. Analysis of NMR and mass spectra revealed that this bioactivity was due to tyramine in the active fraction. Tyramine is present in saw palmetto ethanol extracts and causes indirect α(1)-adrenoceptor mediated contractions via the release of noradrenaline from sympathetic neurons. This has clinical implications, as tyramine interacts with MAO inhibitors to cause hypertensive crisis. © 2010 Wiley-Liss, Inc.

Energy Tax and Competition in Energy Efficiency. The Case of Consumer Durables

International Nuclear Information System (INIS)

Conrad, K.

2000-01-01

The purpose of this paper is to analyze the role of an energy tax on technical improvements and on prices of consumer durables induced by strategic competition in energy efficiency. If the gasoline tax is raised this does in principle not affect the producers of cars because the motorist pays for it in terms of a higher cost of using the car. This, however, affects the unit sales of car producers because of substitution towards other modes of transportation. A second element of reaction to energy price variation is an indirect one and relates to the effect of energy prices on technology. Competition forces car producers to develop more energy efficient cars in order to reduce the cost of using a car. This indirect effect can partly offset the direct effect of higher energy prices on demand if it is profitable for the automobile industry to engineer more energy efficient equipment. We will analyze the impact of an energy tax on energy efficiency and on the price of a durable good. This will be done within the framework of a duopoly competing in prices and in the energy efficiency of its products. The government chooses a welfare maximizing energy tax as an incentive to innovate. Then we will analyze a strategic two-stage decision process in which the duopolists first decide about energy efficiency and then compete in prices. 18 refs

Contrasting impacts of competition on ecological and social trait evolution in songbirds.

Science.gov (United States)

Drury, Jonathan P; Tobias, Joseph A; Burns, Kevin J; Mason, Nicholas A; Shultz, Allison J; Morlon, Hélène

2018-01-01

Competition between closely related species has long been viewed as a powerful selective force that drives trait diversification, thereby generating phenotypic diversity over macroevolutionary timescales. However, although the impact of interspecific competition has been documented in a handful of iconic insular radiations, most previous studies have focused on traits involved in resource use, and few have examined the role of competition across large, continental radiations. Thus, the extent to which broad-scale patterns of phenotypic diversity are shaped by competition remain largely unclear, particularly for social traits. Here, we estimate the effect of competition between interacting lineages by applying new phylogenetic models that account for such interactions to an exceptionally complete dataset of resource-use traits and social signaling traits for the entire radiation of tanagers (Aves, Thraupidae), the largest family of songbirds. We find that interspecific competition strongly influences the evolution of traits involved in resource use, with a weaker effect on plumage signals, and very little effect on song. Our results provide compelling evidence that interspecific exploitative competition contributes to ecological trait diversification among coexisting species, even in a large continental radiation. In comparison, signal traits mediating mate choice and social competition seem to diversify under different evolutionary models, including rapid diversification in the allopatric stage of speciation.

Comment traduire en japonais les styles indirect et indirect libre de Madame Bovary ?

Directory of Open Access Journals (Sweden)

Hisaki Sawasaki

2012-03-01

Full Text Available Parmi les difficultés rencontrées lors de la traduction des textes littéraires occidentaux, en japonais, nous examinons le problème des styles indirect et indirect libre. Pour cela, en effectuant une petite mise au point grammaticale, nous comparons sept traductions de Madame Bovary de Gustave Flaubert, dont les dates de parution s’étendent sur une cinquantaine d’années. Cette période s’apparente, de notre point de vue, à un long itinéraire pour assimiler la notion occidentale des styles direct et indirect, tout en la conciliant avec les particularités du japonais. D’un autre côté, ce travail acharné des traducteurs a influencé quelque peu la langue japonaise. On trouve dans l’annexe tous les textes en japonais examinés.We will examine the difficulties met when translating Western literary texts in Japanese, in particular the problem of indirect and free indirect styles. We will define the grammatical issue and compare seven translations of Madame Bovary, published over a fifty year period. This time can be likened to a long path taken to digest the Western notion of direct and indirect styles, while reconciling it with Japanese language characteristics. On the other hand the translators’ relentless work has somewhat influenced the Japanese language. The annex will present all the Japanese texts examined.

Language shifts in free indirect discourse

NARCIS (Netherlands)

Maier, Emar

Free indirect discourse is a way of reporting what a protagonist thinks or says that is distinct from both direct and indirect discourse. In particular, while pronouns and tenses are presented from the narrator's perspective, as in indirect discourse, other indexical and expressive elements reflect

Directe en indirecte werknemersparticipatie in Europa

NARCIS (Netherlands)

van Houten, Gijs; Akkerman, Agnes; Sluiter, Roderick; Jansen, Giedo; Vermeylen, Greet

2016-01-01

This study looks at different forms of direct and indirect employee participation in the EU. The research questions are: (1) which forms of direct and indirect employee participation can we distinguish?; (2) to what extent do forms of direct and indirect employee participation coincide within

Deflected Mirage Mediation: A Framework for Generalized Supersymmetry Breaking

International Nuclear Information System (INIS)

Kim, Ian-Woo

2008-01-01

We present a model of supersymmetry breaking in which the contributions from gravity/modulus, anomaly, and gauge mediation are all comparable. We term this scenario 'deflected mirage mediation', which is a generalization of the KKLT-motivated mirage mediation scenario to include gauge mediated contributions. These contributions deflect the gaugino mass unification scale and alter the pattern of soft parameters at low energies. Competitive gauge-mediated terms can naturally appear within phenomenological models based on the KKLT setup by the stabilization of the gauge singlet field responsible for the masses of the messenger fields. We analyze the renormalization group evolution of the supersymmetry breaking terms and the resulting low energy mass spectra.

The mediational role of parenting on the longitudinal relation between child personality and externalizing behavior.

Science.gov (United States)

Prinzie, Peter; van der Sluis, Cathy M; de Haan, Amaranta D; Deković, Maja

2010-08-01

Building on prior cross-sectional work, this longitudinal study evaluated the proposition that maternal and paternal overreactive and authoritative parenting mediates the effect of child personality characteristics on externalizing behavior. Data from the Flemish Study on Parenting, Personality, and Problem Behavior were used in a moderated mediation analysis (N=434). Teachers rated children's Big Five characteristics, fathers and mothers rated their parenting, and 3 years later, children rated their externalizing behavior. Mediational analysis revealed both direct and indirect effects. Higher levels of Extraversion and lower levels of Benevolence were related directly to higher levels of child externalizing behavior. Higher levels of paternal authoritative parenting and lower levels of maternal overreactivity were related to lower scores on externalizing behavior. In addition, the relation between Benevolence, Emotional Stability, and externalizing behavior was partially mediated by parental overreactivity. Conscientiousness had an indirect effect on externalizing behavior through paternal authoritative parenting. Relations were not moderated by child gender. This study is of theoretical interest because the results demonstrate that parenting is a mediating mechanism that accounts for associations between personality and externalizing behavior.

Harsh parenting and academic achievement in Chinese adolescents: Potential mediating roles of effortful control and classroom engagement.

Science.gov (United States)

Wang, Mingzhong; Deng, Xueli; Du, Xiuxiu

2018-04-01

This study examined (a) the potential mediating roles of effortful control and classroom engagement in the association between harsh parenting and adolescent academic achievement, and (b) the potential moderating role of gender. Sixth through eighth graders in rural China (n=815, mean age=12.55years) reported on harsh parenting, effortful control, and classroom engagement. Parents also reported on each other's harsh parenting. Academic achievement was assessed by students' test scores and teacher-rated academic performance. Results of structural equation modeling revealed gender differences in patterns of association among the model variables. Harsh parenting was negatively and directly associated with academic achievement for both boys and girls. It was also negatively and indirectly associated with academic achievement via effortful control and classroom engagement sequentially, forming a common indirect "path" for boys and girls. The indirect negative effect of harsh parenting on boys' academic achievement was mainly realized through the mediator of effortful control, whereas this same indirect effect for girls was mainly realized through the mediator of classroom engagement. Jointly, effortful control and classroom engagement precipitates more indirect effects for boys than for girls in the association between harsh parenting and academic achievement. The discussion analyzes the potential "paths" from harsh parenting to adolescent academic achievement, as well as gender differences in these "paths." The current study has implications for teachers and parents eager to improve students' classroom engagement and academic achievement. Copyright © 2017. Published by Elsevier Ltd.

The Impact of Knowledge Management Practices on Supply Chain Quality Management and Competitive Advantages

Directory of Open Access Journals (Sweden)

Azizi Reihaneh

2016-03-01

Full Text Available Achieving competitive advantage enables an organization to create a defensible position against its competitors. It also allows organizations to differentiate themselves from competitors. This study aims to investigate impact of knowledge management practices on supply chain quality management and competitive advantage in Alyaf Company, Iran. This research is functional in purpose and data gathering and data analysis is descriptive-correlation. The statistical population is consists of 25 company executives and experts in the supply chain of Alyaf Company; opinions of 68 of its members were used as a selective sample identified by simple random sampling method. Primary data was collected through questionnaire and structural equation modeling was used to assess relationships between variables. The results of structural equation modeling show a positive and significant causal relationship between knowledge management practices and supply chain quality management. Direct relationship between knowledge management and competitive advantage was not confirmed but the relationship between these two variables was confirmed indirectly.

The logic of indirect speech

Science.gov (United States)

Pinker, Steven; Nowak, Martin A.; Lee, James J.

2008-01-01

When people speak, they often insinuate their intent indirectly rather than stating it as a bald proposition. Examples include sexual come-ons, veiled threats, polite requests, and concealed bribes. We propose a three-part theory of indirect speech, based on the idea that human communication involves a mixture of cooperation and conflict. First, indirect requests allow for plausible deniability, in which a cooperative listener can accept the request, but an uncooperative one cannot react adversarially to it. This intuition is supported by a game-theoretic model that predicts the costs and benefits to a speaker of direct and indirect requests. Second, language has two functions: to convey information and to negotiate the type of relationship holding between speaker and hearer (in particular, dominance, communality, or reciprocity). The emotional costs of a mismatch in the assumed relationship type can create a need for plausible deniability and, thereby, select for indirectness even when there are no tangible costs. Third, people perceive language as a digital medium, which allows a sentence to generate common knowledge, to propagate a message with high fidelity, and to serve as a reference point in coordination games. This feature makes an indirect request qualitatively different from a direct one even when the speaker and listener can infer each other's intentions with high confidence. PMID:18199841

Indirect Cost Reimbursement: An Industrial View.

Science.gov (United States)

Bolton, Robert

1987-01-01

The meaning of indirect costs in an industrial environment is discussed. Other factors considered are corporate policies; nature of work being supported; the uniqueness of the work; who is doing the negotiating for industry; and indirect rates. Suggestions are offered for approaches to indirect cost reimbursement. (Author/MLW)

Motivations for Social Media Use and Impact on Political Participation in China: A Cognitive and Communication Mediation Approach.

Science.gov (United States)

Chen, Zhuo; Chan, Michael

2017-02-01

Integrating uses and gratifications theory and the cognitive/communication mediation model: this study examines Chinese students' use of social media and subsequent impact on political participation. An integrative framework is proposed where media use, political expression, and political cognitions (efficacy and knowledge) play important mediating roles between audience motivations and participation. Structural equation analyses showed support for the integrated model. Guidance and social utility motivations exhibited different indirect effects on online and offline participation through social media news, discussion, and political efficacy. Entertainment motivations exhibited no direct or indirect effects. Contrary to expectations and previous literature, surveillance motivations exhibited negative direct and indirect effects on offline participation, which may be attributed to the particular Chinese social and political context. Implications of the findings are discussed.

Impurity Induced Phase Competition and Supersolidity

Science.gov (United States)

Karmakar, Madhuparna; Ganesh, R.

2017-12-01

Several material families show competition between superconductivity and other orders. When such competition is driven by doping, it invariably involves spatial inhomogeneities which can seed competing orders. We study impurity-induced charge order in the attractive Hubbard model, a prototypical model for competition between superconductivity and charge density wave order. We show that a single impurity induces a charge-ordered texture over a length scale set by the energy cost of the competing phase. Our results are consistent with a strong-coupling field theory proposed earlier in which superconducting and charge order parameters form components of an SO(3) vector field. To discuss the effects of multiple impurities, we focus on two cases: correlated and random distributions. In the correlated case, the CDW puddles around each impurity overlap coherently leading to a "supersolid" phase with coexisting pairing and charge order. In contrast, a random distribution of impurities does not lead to coherent CDW formation. We argue that the energy lowering from coherent ordering can have a feedback effect, driving correlations between impurities. This can be understood as arising from an RKKY-like interaction, mediated by impurity textures. We discuss implications for charge order in the cuprates and doped CDW materials such as NbSe2.

Inverse odds ratio-weighted estimation for causal mediation analysis.

Science.gov (United States)

Tchetgen Tchetgen, Eric J

2013-11-20

An important scientific goal of studies in the health and social sciences is increasingly to determine to what extent the total effect of a point exposure is mediated by an intermediate variable on the causal pathway between the exposure and the outcome. A causal framework has recently been proposed for mediation analysis, which gives rise to new definitions, formal identification results and novel estimators of direct and indirect effects. In the present paper, the author describes a new inverse odds ratio-weighted approach to estimate so-called natural direct and indirect effects. The approach, which uses as a weight the inverse of an estimate of the odds ratio function relating the exposure and the mediator, is universal in that it can be used to decompose total effects in a number of regression models commonly used in practice. Specifically, the approach may be used for effect decomposition in generalized linear models with a nonlinear link function, and in a number of other commonly used models such as the Cox proportional hazards regression for a survival outcome. The approach is simple and can be implemented in standard software provided a weight can be specified for each observation. An additional advantage of the method is that it easily incorporates multiple mediators of a categorical, discrete or continuous nature. Copyright © 2013 John Wiley & Sons, Ltd.

Competitive Dominance by a Bacteriocin-Producing Vibrio harveyi Strain.

Science.gov (United States)

Hoyt, P R; Sizemore, R K

1982-09-01

Vibrio (Beneckea) harveyi, a bioluminescent marine bacterium, has been shown to produce a bacteriocin-like substance the production of which is mediated by a plasmid. This substance is assumed to be proteinaceous because of its sensitivity to certain proteolytic enzymes. It is stable at low temperatures and can be concentrated by ammonium sulfate precipitation or negative-pressure dialysis. The molecular weight of the bacteriocin was determined to be 2.4 x 10 by molecular exclusion chromatography. Competition experiments indicated that bacteriocin-producing strains predominated over cured variants of the same strain in broth culture experiments. We studied several environmental parameters (pH, salinity, temperature, nutrient concentration) to determine their effects on the competitive advantage bestowed on a bacteriocin-producing strain. Under simulated free-living conditions, no competitive advantage attributable to bacteriocin production was observed. In a simulated enteric habitat, a bacteriocin-producing strain showed dramatic (>90%) inhibition of the sensitive strain within 24 h.

The relationship among image, satisfaction and loyalty – innovative factor of competitiveness for shopping centers

OpenAIRE

Abrudan, Ioana-Nicoleta; Plaias, Ioan; Dabija, Dan-Cristian

2015-01-01

Currently, most markets are characterized by high competition among shopping centers. Under these circumstances, the evolution in the competitiveness and performance of the centers is increasingly linked to the success in the innovation of current activities, which is aimed at improving their image and increasing customer satisfaction and loyalty. The purpose of the present research is to study the influence of innovation activities through the image components on behavioural loyalty, mediate...

Has renewable energy induced competitive behavior in the Spanish electricity market?

International Nuclear Information System (INIS)

Ciarreta, Aitor; Espinosa, Maria Paz; Pizarro-Irizar, Cristina

2017-01-01

Recent energy policy has favored a massive introduction of Renewable Energy Sources on electricity markets, which has greatly impacted their performance. First, the electricity price has decreased as a consequence of the so-called merit-order effect. Another relevant effect is associated to the intermittent nature of Renewable Energy, which has increased the cost of ancillary services. A third and important aspect, less addressed in the literature, is the induced change in the strategic behavior of the conventional electricity producers. In principle, the entry of new generators in a concentrated market would make it more competitive and change the strategic behavior of the incumbents. We test this hypothesis for the Spanish wholesale market. While we find no significant change in behavior for Nuclear, Hydropower and Coal, a change is observed in Combined Cycle bidding strategies after the entry of renewable generators. Our analysis shows that the massive entry of Renewable Energy Sources made other generators' behavior more competitive in the short run, but the effect was not persistent. - Highlights: • The indirect effects of RES affect prices in electricity markets. • RES induced little change in Nuclear, Coal and Hydropower generation. • Combined Cycle bidding strategies have evolved to adapt to the introduction of RES. • RES made Combined Cycle's behavior more competitive in the short run. • The competitive effect induced by RES is not persistent in the long run.

Preparation of anti-Sudan red monoclonal antibody and development of an indirect competitive enzyme-linked immunosorbent assay for detection of Sudan red in chilli jam and chilli oil.

Science.gov (United States)

Xu, Jing; Zhang, Yuanyang; Yi, Jian; Meng, Meng; Wan, Yuping; Feng, Caiwei; Wang, Shanliang; Lu, Xiao; Xi, Rimo

2010-10-01

Sudan dyes are banned to be used in food additives because of the carcinogenicity of their metabolites. A rapid and sensitive indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed to detect the residues of Sudan dyes. Novel immunogen and coating antigen were synthesized via glutaraldehyde linking. The hapten-bovine serum albumin (BSA) was applied as immunogen and the hapten-ovalbumin (OVA) was served as coating antigen. The monoclonal antibody obtained showed high sensitivity to Sudan I with an IC(50) value of 1.7 μg L(-1) in buffer and was suitable to detect the residues of Sudan red in food products. The specificity of the assay was studied by measuring cross-reactivity of the antibody with the structurally related compounds of Sudan II (red (120%). Chilli jam and chilli oil samples spiked with Sudan dyes were analyzed by the method. The detection limit (LOD) of the ELISA method applied in chilli jam and chilli oil was 9.0 μg L(-1) and 19.6 μg L(-1), respectively. The recovery rates of Sudan-I in chilli oil and chilli jam were in the range of 80%-110% with coefficients of variation <25%. The intra-assay variation and inter-assay variation in buffer were both <9%.

Reports of adolescent emotion regulation and school engagement mediating the relation between parenting and adolescent functioning in India.

Science.gov (United States)

Raval, Vaishali V; Ward, Rose M; Raval, Pratiksha H; Trivedi, Shwetang S

2017-02-07

Much like other parts of Asia, late adolescence in India is a particularly stressful time with academic pressures of a highly competitive examination system that determines future occupational success. The present study examined interrelations among reports of parenting, adolescents' regulation of academics-related emotions, school engagement, adolescent socio-emotional functioning and state-exam performance. Four hundred and fifty 10th and 12th graders from suburban high schools in India participated, along with their mothers. At the beginning of the school year, mothers completed measures of parenting, and adolescents completed measures of emotion regulation, school engagement and behaviour problems. At the end of the school year, grades from state exams were obtained from the schools. A multiple mediator model was tested using structural equation modelling. Authoritarian parenting was positively related to adolescent behaviour problems, but not adolescent state-exam performance. Maternal non-supportive responses to adolescent negative emotion were indirectly positively related to adolescent behaviour problems through adolescent emotion dysregulation. Adolescent school engagement mediated the positive relation between maternal supportive responses to adolescent negative emotion and adolescent state-exam performance. These findings underscore the relevance of adolescent emotions for their academic functioning, with implications for the development of interventions for those who struggle during these highly stressful years. © 2017 International Union of Psychological Science.

c-Myc-Dependent Cell Competition in Human Cancer Cells.

Science.gov (United States)

Patel, Manish S; Shah, Heta S; Shrivastava, Neeta

2017-07-01

Cell Competition is an interaction between cells for existence in heterogeneous cell populations of multicellular organisms. This phenomenon is involved in initiation and progression of cancer where heterogeneous cell populations compete directly or indirectly for the survival of the fittest based on differential gene expression. In Drosophila, cells having lower dMyc expression are eliminated by cell competition through apoptosis when present in the milieu of cells having higher dMyc expression. Thus, we designed a study to develop c-Myc (human homolog) dependent in vitro cell competition model of human cancer cells. Cells with higher c-Myc were transfected with c-myc shRNA to prepare cells with lower c-Myc and then co-cultured with the same type of cells having a higher c-Myc in equal ratio. Cells with lower c-Myc showed a significant decrease in numbers when compared with higher c-Myc cells, suggesting "loser" and "winner" status of cells, respectively. During microscopy, engulfment of loser cells by winner cells was observed with higher expression of JNK in loser cells. Furthermore, elimination of loser cells was prevented significantly, when co-cultured cells were treated with the JNK (apoptosis) inhibitor. Above results indicate elimination of loser cells in the presence of winner cells by c-Myc-dependent mechanisms of cell competition in human cancer cells. This could be an important mechanism in human tumors where normal cells are eliminated by c-Myc-overexpressed tumor cells. J. Cell. Biochem. 118: 1782-1791, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Statistical properties of four effect-size measures for mediation models.

Science.gov (United States)

Miočević, Milica; O'Rourke, Holly P; MacKinnon, David P; Brown, Hendricks C

2018-02-01

This project examined the performance of classical and Bayesian estimators of four effect size measures for the indirect effect in a single-mediator model and a two-mediator model. Compared to the proportion and ratio mediation effect sizes, standardized mediation effect-size measures were relatively unbiased and efficient in the single-mediator model and the two-mediator model. Percentile and bias-corrected bootstrap interval estimates of ab/s Y , and ab(s X )/s Y in the single-mediator model outperformed interval estimates of the proportion and ratio effect sizes in terms of power, Type I error rate, coverage, imbalance, and interval width. For the two-mediator model, standardized effect-size measures were superior to the proportion and ratio effect-size measures. Furthermore, it was found that Bayesian point and interval summaries of posterior distributions of standardized effect-size measures reduced excessive relative bias for certain parameter combinations. The standardized effect-size measures are the best effect-size measures for quantifying mediated effects.

Indirect Calorimetry in Mechanically Ventilated Patients

DEFF Research Database (Denmark)

Allingstrup, Matilde Jo; Kondrup, Jens; Perner, Anders

2017-01-01

Background and Aims: The 2 currently available indirect calorimeters, CCM Express Indirect Calorimeter (MedGraphics, St Paul, MN) and Quark RMR ICU Indirect Calorimeter (COSMED, Rome, Italy), have not been validated against a gold standard in mechanically ventilated patients. Our aim was to do so...... using a gold-standard, modified Tissot bell-spirometer method in mechanically ventilated patients who were hemodynamically, respiratory, and metabolically stable. Methods: We studied 30 patients undergoing general anesthesia and major gynecological surgery. We measured oxygen consumption ((Formula...... of 77 (167) with limits of agreement −249 to 404 kcal/d. Conclusions: The QUARK RMR ICU Indirect Calorimeter compared better with the gold standard for values of (Formula presented.) O2 and REE than did the CCM Express Indirect Calorimeter in mechanically ventilated patients who were circulatory...

CCND1-CDK4-mediated cell cycle progression provides a competitive advantage for human hematopoietic stem cells in vivo.

Science.gov (United States)

Mende, Nicole; Kuchen, Erika E; Lesche, Mathias; Grinenko, Tatyana; Kokkaliaris, Konstantinos D; Hanenberg, Helmut; Lindemann, Dirk; Dahl, Andreas; Platz, Alexander; Höfer, Thomas; Calegari, Federico; Waskow, Claudia

2015-07-27

Maintenance of stem cell properties is associated with reduced proliferation. However, in mouse hematopoietic stem cells (HSCs), loss of quiescence results in a wide range of phenotypes, ranging from functional failure to extensive self-renewal. It remains unknown whether the function of human HSCs is controlled by the kinetics of cell cycle progression. Using human HSCs and human progenitor cells (HSPCs), we report here that elevated levels of CCND1-CDK4 complexes promoted the transit from G0 to G1 and shortened the G1 cell cycle phase, resulting in protection from differentiation-inducing signals in vitro and increasing human leukocyte engraftment in vivo. Further, CCND1-CDK4 overexpression conferred a competitive advantage without impacting HSPC numbers. In contrast, accelerated cell cycle progression mediated by elevated levels of CCNE1-CDK2 led to the loss of functional HSPCs in vivo. Collectively, these data suggest that the transition kinetics through the early cell cycle phases are key regulators of human HSPC function and important for lifelong hematopoiesis. © 2015 Mende et al.

Ecological trade-offs between jasmonic acid-dependent direct and indirect plant defences in tritrophic interactions.

Science.gov (United States)

Wei, Jianing; Wang, Lizhong; Zhao, Jiuhai; Li, Chuanyou; Ge, Feng; Kang, Le

2011-01-01

Recent studies on plants genetically modified in jasmonic acid (JA) signalling support the hypothesis that the jasmonate family of oxylipins plays an important role in mediating direct and indirect plant defences. However, the interaction of two modes of defence in tritrophic systems is largely unknown. In this study, we examined the preference and performance of a herbivorous leafminer (Liriomyza huidobrensis) and its parasitic wasp (Opius dissitus) on three tomato genotypes: a wild-type (WT) plant, a JA biosynthesis (spr2) mutant, and a JA-overexpression 35S::prosys plant. Their proteinase inhibitor production and volatile emission were used as direct and indirect defence factors to evaluate the responses of leafminers and parasitoids. Here, we show that although spr2 mutant plants are compromised in direct defence against the larval leafminers and in attracting parasitoids, they are less attractive to adult flies compared with WT plants. Moreover, in comparison to other genotypes, the 35S::prosys plant displays greater direct and constitutive indirect defences, but reduced success of parasitism by parasitoids. Taken together, these results suggest that there are distinguished ecological trade-offs between JA-dependent direct and indirect defences in genetically modified plants whose fitness should be assessed in tritrophic systems and under natural conditions. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

Modelling the co-evolution of indirect genetic effects and inherited variability.

Science.gov (United States)

Marjanovic, Jovana; Mulder, Han A; Rönnegård, Lars; Bijma, Piter

2018-03-28

When individuals interact, their phenotypes may be affected not only by their own genes but also by genes in their social partners. This phenomenon is known as Indirect Genetic Effects (IGEs). In aquaculture species and some plants, however, competition not only affects trait levels of individuals, but also inflates variability of trait values among individuals. In the field of quantitative genetics, the variability of trait values has been studied as a quantitative trait in itself, and is often referred to as inherited variability. Such studies, however, consider only the genetic effect of the focal individual on trait variability and do not make a connection to competition. Although the observed phenotypic relationship between competition and variability suggests an underlying genetic relationship, the current quantitative genetic models of IGE and inherited variability do not allow for such a relationship. The lack of quantitative genetic models that connect IGEs to inherited variability limits our understanding of the potential of variability to respond to selection, both in nature and agriculture. Models of trait levels, for example, show that IGEs may considerably change heritable variation in trait values. Currently, we lack the tools to investigate whether this result extends to variability of trait values. Here we present a model that integrates IGEs and inherited variability. In this model, the target phenotype, say growth rate, is a function of the genetic and environmental effects of the focal individual and of the difference in trait value between the social partner and the focal individual, multiplied by a regression coefficient. The regression coefficient is a genetic trait, which is a measure of cooperation; a negative value indicates competition, a positive value cooperation, and an increasing value due to selection indicates the evolution of cooperation. In contrast to the existing quantitative genetic models, our model allows for co-evolution of

Longitudinal Mediation of Processing Speed on Age-Related Change in Memory and Fluid Intelligence

Science.gov (United States)

Robitaille, Annie; Piccinin, Andrea M.; Muniz, Graciela; Hoffman, Lesa; Johansson, Boo; Deeg, Dorly J.H.; Aartsen, Marja J.; Comijs, Hannie C.; Hofer, Scott M.

2014-01-01

Age-related decline in processing speed has long been considered a key driver of cognitive aging. While the majority of empirical evidence for the processing speed hypothesis has been obtained from analyses of between-person age differences, longitudinal studies provide a direct test of within-person change. Using recent developments in longitudinal mediation analysis, we examine the speed–mediation hypothesis at both the within- and between-person levels in two longitudinal studies, LASA and OCTO-Twin. We found significant within-person indirect effects of change in age, such that increasing age was related to lower speed which, in turn, relates to lower performance across repeated measures on other cognitive outcomes. Although between-person indirect effects were also significant in LASA, they were not in OCTO-Twin. These differing magnitudes of direct and indirect effects across levels demonstrate the importance of separating between- and within-person effects in evaluating theoretical models of age-related change. PMID:23957224

An exploration of competitiveness and caring in relation to psychopathology.

Science.gov (United States)

McEwan, Kirsten; Gilbert, Paul; Duarte, Joana

2012-03-01

Social mentality theory outlines how specialist systems have evolved to facilitate different types of social behaviour such as caring for offspring, forming alliances, and competing for resources. This research explored how different types of self-experience are linked to the different social mentalities of competitive social ranking (focusing on gaining and defending one's social position/status/rank) in contrast to caring (being helpful to others). Perceived low social rank (with feelings of being inferior and unfavourable social comparison, SC) has been linked to depression, but a caring sense of self has less so. We hypothesized therefore that depression, in both clinical and non-clinical populations, would be primarily linked to competitive and rank focused sense of self rather than a caring sense of self. Students (N = 312) and patients with depression (N = 48) completed self-report scales measuring: self-experience related to competitiveness and caring; social rank; social safeness; and depression, anxiety, and stress. The data suggest that in students, and particularly in patients, competitiveness (and feeling unsuccessful in competing for resources) is strongly associated with depression. Although caring shares a small correlation with depression in students, and with depression, anxiety, and stress in patients, when controlling for the rank variable of submissive behaviour this relationship ceases to be significant. Submissive behaviour was found to be a full mediator between caring and depression. We also found that how safe and comfortable one feels in one's social relationships (social safeness), was a full mediator between competitiveness and depression. So, it is the feeling of being unable to compete where one does not feel secure in one's social environment that is particularly linked to depression. The results of this study suggest that self-experience is complex and multifaceted and is linked to different social roles that are socially

EDITORIAL: Physics competitions Physics competitions

Science.gov (United States)

Jordens, H.; Mathelitsch, L.

2009-11-01

1. Physics competitions: aims and realizations One aim of physics competitions is to increase the interest of young students, primarily at upper secondary level, to physics and natural sciences in general. A competition has motivational aspects known usually from sports events or games—comparing one's own ability with others, of course with the desire to be better and to win. If competitions reach nationwide and even international levels, additional stimulation is created. Competitions provide greatest attraction to possible winners, to the group of gifted people in a particular field. This implies that science contests are excellent tools for the promotion of talented students. Traditional teaching has been shown to have problems in supporting this group of students. Very often teachers are overstretched with the demands of teaching both low- and high-level students. Extracurricular activities are therefore a good chance to relieve the teacher, and to give talented students the opportunity for appropriate training and challenge. The competitions, however, have a broader impact and address more young people than one might guess from the statements above. Training courses and selection at school level give a larger group of students extra and, to some extent, complimentary education in physics. The degree of complexity of the tasks corresponds very often to the standards of the next level of education in the school system. Interestingly, many physics competitions have their origin in countries beyond the former Iron Curtain. They started as regional and national tournaments, were joined by neighbouring countries and have grown, in some cases, to events with participants from more than 80 countries. Although the features mentioned above are common to the different competitions, there are distinct differences between them [1]. The International Physics Olympiad (IPhO) is the oldest international physics competition for students at upper secondary level [2]. It dates

A simplified indirect bonding technique

Directory of Open Access Journals (Sweden)

Radha Katiyar

2014-01-01

Full Text Available With the advent of lingual orthodontics, indirect bonding technique has become an integral part of practice. It involves placement of brackets initially on the models and then their transfer to teeth with the help of transfer trays. Problems encountered with current indirect bonding techniques used are (1 the possibility of adhesive flash remaining around the base of the brackets which requires removal (2 longer time required for the adhesive to gain enough bond strength for secure tray removal. The new simplified indirect bonding technique presented here overcomes both these problems.

COMPETITIVENESS AND COMPETITIVE ORIENTATIONS: EVALUATION OF STUDENTS

Directory of Open Access Journals (Sweden)

G. Z. Efimova

2017-01-01

Full Text Available Introduction. Education of a competitive student is a strategically significant problem of the system of higher education in modern social and economic conditions. Personal competitiveness and competitive orientations – priority quality of future expert for successful future professional experience.The aim of the present research is to study factors of competitive orientations formation and criteria for evaluation of competitiveness of student’s youth in the Russian society.Methodology and research methods. Results of theoretical researches of Russian and foreign researchers are generalized; secondary analysis of data based on results of sociological researches and analysis of official statistical data are carried out. The results of the sociological survey undertaken in 2017 on the basis of statistical methods were processed and studied by the instrumentality of IBM SPSS Statistics 23 program; 1196 students of institutions of higher and secondary vocational education of the Tyumen region took part.Results and scientific novelty. It is stated that senior students feel themselves more competitive. It is revealed that a quarter of students who took part in the survey, generally men, count themselves competitive. A continuous distance of goal-setting is recorded among these respondents; in every third case they have plans of professional growth for five and more years that allows them to build attractive competitive strategy.The level of the competitiveness is directly connected with such indicators as “social stratum”, “overall life satisfaction”, “self-esteem of health”, “tendency to lead a healthy lifestyle” and “the level of trust in the surrounding people”. Mostly the students oriented on competition look into the future with confidence and optimism.Respondents focused on the competitiveness were more tend to demonstrate their abilities and cause admiration, have a creative approach towards work, be ready for surprises

Big five personality and adolescent Internet addiction: The mediating role of coping style.

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Zhou, Yueyue; Li, Dongping; Li, Xian; Wang, Yanhui; Zhao, Liyan

2017-01-01

This study examined the unique associations between big five personality traits and adolescent Internet addiction (IA), as well as the mediating role of coping style underlying these relations. Our theoretical model was tested with 998 adolescents. Participants provided self-report data on demographic variables, big five personality traits, coping style, and IA. After controlling for demographic variables, it was found that agreeableness and conscientiousness were negatively associated with IA, whereas extraversion, neuroticism, and openness to experience were positively associated with IA. Mediation analyses further indicated that conscientiousness had an indirect impact on adolescent IA through decreased emotion-focused coping, whereas extraversion, neuroticism, openness to experience had indirect impacts on adolescent IA through increased emotion-focused coping. In contrast, problem-focused coping had no mediating role. These findings suggest that emotion-focused coping may, in part, account for the association between big five personality and adolescent IA. Copyright © 2016 Elsevier Ltd. All rights reserved.

Selecting a model of supersymmetry breaking mediation

International Nuclear Information System (INIS)

AbdusSalam, S. S.; Allanach, B. C.; Dolan, M. J.; Feroz, F.; Hobson, M. P.

2009-01-01

We study the problem of selecting between different mechanisms of supersymmetry breaking in the minimal supersymmetric standard model using current data. We evaluate the Bayesian evidence of four supersymmetry breaking scenarios: mSUGRA, mGMSB, mAMSB, and moduli mediation. The results show a strong dependence on the dark matter assumption. Using the inferred cosmological relic density as an upper bound, minimal anomaly mediation is at least moderately favored over the CMSSM. Our fits also indicate that evidence for a positive sign of the μ parameter is moderate at best. We present constraints on the anomaly and gauge mediated parameter spaces and some previously unexplored aspects of the dark matter phenomenology of the moduli mediation scenario. We use sparticle searches, indirect observables and dark matter observables in the global fit and quantify robustness with respect to prior choice. We quantify how much information is contained within each constraint.

Dark matter prospects in deflected mirage mediation

International Nuclear Information System (INIS)

Holmes, Michael; Nelson, Brent D.

2009-01-01

The recently introduced deflected mirage mediation (DMM) model is a string-motivated paradigm in which all three of the major supersymmetry-breaking transmission mechanisms are operative. We begin a systematic exploration of the parameter space of this rich model context, paying special attention to the pattern of gaugino masses which arise. In this work we focus on the dark matter phenomenology of the DMM model as such signals are the least influenced by the model-dependent scalar masses. We find that a large portion of the parameter space in which the three mediation mechanisms have a similar effective mass scale of 1 TeV or less will be probed by future direct and indirect detection experiments. Distinguishing deflected mirage mediation from the mirage model without gauge mediation will prove difficult without collider input, though we indicate how gamma ray signals may provide an opportunity for distinguishing between the two paradigms

Nuclear famine: The indirect effects of nuclear war

International Nuclear Information System (INIS)

Harwell, M.A.; Harwell, C.C.

1986-01-01

The indirect effects of a nuclear war, especially as mediated by disruption in food availability, could be much more extensive than the direct effects. Furthermore, this risk is especially severe for noncombatant countries - for the 4 billion or so humans expected to survive the immediate period after a nuclear war relatively physically unharmed. Thus, a fundamentally different picture of the post-nuclear-war world results, where a large-scale nuclear war between the United States and the Soviet Union would probably result in more eventual fatalities in India than in the United States and the Soviet Union combined, and more people would die on the African continent than in all of Europe. Rather than reflecting images of Hiroshima and Nagasaki, a modern nuclear war would, for most of the people of the world, much more resemble current images of Ethiopia and the Sudan

The ironic effect of guessing: increased false memory for mediated lists in younger and older adults

Science.gov (United States)

Coane, Jennifer H.; Huff, Mark J.; Hutchison, Keith A.

2016-01-01

Younger and older adults studied lists of words directly (e.g., creek, water) or indirectly (e.g., beaver, faucet) related to a nonpresented critical lure (CL; e.g., river). Indirect (i.e., mediated) lists presented items that were only related to CLs through nonpresented mediators (i.e., directly related items). Following study, participants completed a condition-specific task, math, a recall test with or without a warning about the CL, or tried to guess the CL. On a final recognition test, warnings (vs. math and recall without warning) decreased false recognition for direct lists, and guessing increased mediated false recognition (an ironic effect of guessing) in both age groups. The observed age-invariance of the ironic effect of guessing suggests that processes involved in mediated false memory are preserved in aging and confirms the effect is largely due to activation in semantic networks during encoding and to the strengthening of these networks during the interpolated tasks. PMID:26393390

Parenting stress mediates the association between negative affectivity and harsh parenting: A longitudinal dyadic analysis.

Science.gov (United States)

Le, Yunying; Fredman, Steffany J; Feinberg, Mark E

2017-09-01

The current study examined parenting stress (disaggregated into personal distress and child rearing stress) at 12 months postpartum as a mediator of the longitudinal association between parental negative affectivity at 6 months postpartum and harsh parenting at 3 years postpartum for first-time parents with a child transitioning from late toddlerhood to the early preschool years. Analyses were conducted using Mediation for Actor Partner Interdependence Modeling in a sample of 164 couples who participated in a randomized controlled trial of a universal, couple-based transition to parenthood program. There were indirect actor effects of negative affect on a parent's own harsh parenting through both dimensions of parenting stress, with a stronger mediating effect for personal distress than child rearing stress. There were also indirect partner effects of negative affect on one's partner's harsh parenting through the partner's parenting stress, with a stronger indirect partner effect from mothers' negative affect to fathers' harsh parenting than vice versa. Specifically, the mediating effect of personal distress was found for both mothers and fathers, whereas the mediating effect of child rearing stress was found from mothers' negative affect to fathers' harsh parenting only. Findings highlight the importance of a dyadic approach in examining the longitudinal association between negative affect and harsh parenting and suggest that reducing parenting stress in the first year postpartum may decrease the risk of future harsh parenting among couples in which one or both partners experience negative affectivity. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Mediators and moderators in early intervention research.

Science.gov (United States)

Breitborde, Nicholas J K; Srihari, Vinod H; Pollard, Jessica M; Addington, Donald N; Woods, Scott W

2010-05-01

The goal of this paper is to provide clarification with regard to the nature of mediator and moderator variables and the statistical methods used to test for the existence of these variables. Particular attention will be devoted to discussing the ways in which the identification of mediator and moderator variables may help to advance the field of early intervention in psychiatry. We completed a literature review of the methodological strategies used to test for mediator and moderator variables. Although several tests for mediator variables are currently available, recent evaluations suggest that tests which directly evaluate the indirect effect are superior. With regard to moderator variables, two approaches ('pick-a-point' and regions of significance) are available, and we provide guidelines with regard to how researchers can determine which approach may be most appropriate to use for their specific study. Finally, we discuss how to evaluate the clinical importance of mediator and moderator relationships as well as the methodology to calculate statistical power for tests of mediation and moderation. Further exploration of mediator and moderator variables may provide valuable information with regard to interventions provided early in the course of a psychiatric illness.

Ionization versus indirect effects of ionizing radiation on cellular DNA

International Nuclear Information System (INIS)

Cadet, Jean; Ravanat, Jean-Luc; Douki, Thierry

2012-01-01

Emphasis has been placed in the last decade on the elucidation of the main degradation pathways of isolated DNA mediated by hydroxyl radical (OH) and one-electron oxidation reactions as the result of indirect and direct effects of ionizing radiation respectively. This has led to the isolation and characterization of about 100 oxidized purine and pyrimidine nucleosides if hydroperoxide precursors and diastereomers are included. However, far less information is available on the mechanisms of radiation-induced degradation of bases in cellular DNA mostly due partly to analytical difficulties. It may be reminded that the measurement of oxidized nucleosides and bases in nuclear DNA is still a challenging issue which until recently has been hampered by the use of inappropriate methods such as the GC-MS that have led to overestimated values of the lesions by factors varying between two and three orders of magnitude. At the present, using the accurate and sensitive HPLC/MS/MS assay, 11 single modified nucleosides and bases were found to be generated in cellular DNA upon exposure to gamma rays and heavy ions. This validates several of the OH-mediated oxidation pathways of thymine, guanine and adenine that were previously inferred from model studies. The concomitant decrease in the yields of oxidized bases with the increase in the LET of heavy ions is accounted for by the preponderance of indirect effects in the damaging action of ionizing radiation on DNA. Further evidence for the major role played by .OH was provided by the results of exposure of cells to high intensity 266 nm laser pulses. Under these conditions 8-oxo-7,8-dihydroguanine is mostly produced by biphotonic ionization of DNA nucleobases and subsequent hole migration to guanine bases. It is likely that some of the oxidized bases that have been isolated as single lesions are in fact involved in clustered damage. Interestingly it was recently shown that a single oxidation hit is capable of generating complex

A complete graphical criterion for the adjustment formula in mediation analysis.

Science.gov (United States)

Shpitser, Ilya; VanderWeele, Tyler J

2011-03-04

Various assumptions have been used in the literature to identify natural direct and indirect effects in mediation analysis. These effects are of interest because they allow for effect decomposition of a total effect into a direct and indirect effect even in the presence of interactions or non-linear models. In this paper, we consider the relation and interpretation of various identification assumptions in terms of causal diagrams interpreted as a set of non-parametric structural equations. We show that for such causal diagrams, two sets of assumptions for identification that have been described in the literature are in fact equivalent in the sense that if either set of assumptions holds for all models inducing a particular causal diagram, then the other set of assumptions will also hold for all models inducing that diagram. We moreover build on prior work concerning a complete graphical identification criterion for covariate adjustment for total effects to provide a complete graphical criterion for using covariate adjustment to identify natural direct and indirect effects. Finally, we show that this criterion is equivalent to the two sets of independence assumptions used previously for mediation analysis.

Intolerance of sexy peers: intrasexual competition among women.

Science.gov (United States)

Vaillancourt, Tracy; Sharma, Aanchal

2011-01-01

Intrasexual competition among males of different species, including humans, is well documented. Among females, far less is known. Recent nonexperimental studies suggest that women are intolerant of attractive females and use indirect aggression to derogate potential rivals. In Study 1, an experimental design was used to test the evolutionary-based hypothesis that women would be intolerant of sexy women and would censure those who seem to make sex too readily available. Results provide strong empirical support for intrasexual competition among women. Using independent raters, blind to condition, we found that almost all women were rated as reacting negatively ("bitchy") to an attractive female confederate when she was dressed in a sexually provocative manner. In contrast, when she was dressed conservatively, the same confederate was barely noticed by the participants. In Study 2, an experimental design was used to assess whether the sexy female confederate from Study 1 was viewed as a sexual rival by women. Results indicated that as hypothesized, women did not want to introduce her to their boyfriend, allow him to spend time alone with her, or be friends with her. Findings from both studies are discussed in terms of evolutionary theory. © 2011 Wiley Periodicals, Inc.

Smoking and subsequent human papillomavirus infection: a mediation analysis.

Science.gov (United States)

Eldridge, Ronald C; Pawlita, Michael; Wilson, Lauren; Castle, Philip E; Waterboer, Tim; Gravitt, Patti E; Schiffman, Mark; Wentzensen, Nicolas

2017-11-01

Smoking is an established risk factor for a human papillomavirus (HPV) infection advancing to cervical precancer and cancer, but its role earlier in the natural history is less clear. Smoking is inversely associated with possessing HPV antibodies from a past infection suggesting that smoking may influence acquiring subsequent infections. In a cohort of 1976 U.S. women, we evaluate whether reduced antibodies to HPV-16 is a mechanism for smoking's role on acquiring a subsequent HPV-16 infection, through the analytic technique of causal mediation analysis. We posit a causal model and estimate two counterfactually defined effects: a smoking impaired antibody-mediated indirect effect and a nonmediated direct effect representing all other potential mechanisms of smoking. Compared to never smokers, current smokers had increased odds of HPV-16 infection by the antibody-mediated indirect effect (odds ratio [OR] = 1.29; 95% confidence interval [CI]: 1.11, 1.73); the estimated direct effect was very imprecise (OR = 0.57; 95% CI, 0.26-1.13). We observed a stronger estimated indirect effect among women who smoked at least half a pack of cigarettes daily (OR = 1.61, 95% CI, 1.27-2.15) than among women who smoked less than that threshold (OR = 1.09; 95% CI, 0.94-1.44). This is the first study to directly test the mechanism underlying smoking as an HPV cofactor. The results support current smoking as a risk factor earlier in the natural history of HPV and are consistent with the hypothesis that smoking increases the risk of a subsequent infection by reducing immunity. Published by Elsevier Inc.

Multiple mechanisms enable invasive species to suppress native species.

Science.gov (United States)

Bennett, Alison E; Thomsen, Meredith; Strauss, Sharon Y

2011-07-01

Invasive plants represent a significant threat to ecosystem biodiversity. To decrease the impacts of invasive species, a major scientific undertaking of the last few decades has been aimed at understanding the mechanisms that drive invasive plant success. Most studies and theories have focused on a single mechanism for predicting the success of invasive plants and therefore cannot provide insight as to the relative importance of multiple interactions in predicting invasive species' success. We examine four mechanisms that potentially contribute to the success of invasive velvetgrass Holcus lanatus: direct competition, indirect competition mediated by mammalian herbivores, interference competition via allelopathy, and indirect competition mediated by changes in the soil community. Using a combination of field and greenhouse approaches, we focus on the effects of H. lanatus on a common species in California coastal prairies, Erigeron glaucus, where the invasion is most intense. We found that H. lanatus had the strongest effects on E. glaucus via direct competition, but it also influenced the soil community in ways that feed back to negatively influence E. glaucus and other native species after H. lanatus removal. This approach provided evidence for multiple mechanisms contributing to negative effects of invasive species, and it identified when particular strategies were most likely to be important. These mechanisms can be applied to eradication of H. lanatus and conservation of California coastal prairie systems, and they illustrate the utility of an integrated set of experiments for determining the potential mechanisms of invasive species' success.

Indirect Reciprocity; A Field Experiment.

Science.gov (United States)

van Apeldoorn, Jacobien; Schram, Arthur

2016-01-01

Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream) or after receiving kindness from others oneself (upstream). It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has been widely studied theoretically, the empirical evidence of indirect reciprocity has thus far been limited and based solely on behavior in laboratory experiments. We provide evidence from an online environment where members can repeatedly ask and offer services to each other, free of charge. For the purpose of this study we created several new member profiles, which differ only in terms of their serving history. We then sent out a large number of service requests to different members from all over the world. We observe that a service request is more likely to be rewarded for those with a profile history of offering the service (to third parties) in the past. This provides clear evidence of (downstream) indirect reciprocity. We find no support for upstream indirect reciprocity (in this case, rewarding the service request after having previously received the service from third parties), however. Our evidence of downstream indirect reciprocity cannot be attributed to reputational effects concerning one's trustworthiness as a service user.

The Effect of Religious Involvement on Life Satisfaction among Korean Christians: Focused on the Mediating Effect of Spiritual Well-Being and Self-Esteem.

Science.gov (United States)

Yoo, Jieun

2017-12-01

The present study examined the relationship between two categories of religious involvement, namely religious belief and religious behavior, and life satisfaction among Korean Christians (N = 278) with spiritual well-being and self-esteem as potential mediators in this relationship by using structural equation modeling (SEM). The results supported the full mediated structural model and indicated that religious belief had a significant indirect effect on life satisfaction through the mediators, spiritual well-being and self-esteem. Religious behavior did not have an indirect or direct effect on life satisfaction among Korean Christians. The significance, implications, and limitations of the study were discussed.

Finding benefits from acculturative stress among Asian Americans: Self-reflection moderating the mediating effects of ethnocultural empathy on positive outcomes.

Science.gov (United States)

Wei, Meifen; Li, Chun-I; Wang, Cixin; Ko, Stacy Y

2016-11-01

This study examined a moderated mediation model to see whether self-reflection moderated (a) the association between acculturative stress and ethnocultural empathy and (b) the indirect effects of acculturative stress on 2 positive outcomes (i.e., bicultural competence and making positive sense of adversity) through ethnocultural empathy. A total of 330 Asian American college students from a West coast university participated in an online survey. Results from PROCESS supported hypotheses. First, self-reflection significantly moderated the effects of acculturative stress on ethnocultural empathy. Specifically, the effect of acculturative stress on ethnocultural empathy was significantly positive for those with lower self-reflection. Conversely, this effect was not significant for those with higher self-reflection, but ethnocultural empathy was consistently high across all levels of acculturative stress for those with higher self-reflection. Post hoc exploratory analyses examined the moderated mediation model using each of the 5 domains of acculturative stress as predictors; results supported the moderated mediation hypotheses for 2 domains, discrimination and cultural isolation. Second, self-reflection significantly moderated the indirect effects of acculturative stress on 2 positive outcomes through ethnocultural empathy. Results from conditional indirect effects suggested that the indirect effects of acculturative stress on 2 positive outcomes through ethnocultural empathy were significantly positive for those with lower self-reflection. Conversely, the indirect effects were not significant for those with higher self-reflection, but the 2 positive outcomes stayed high at all levels of acculturative stress. Post hoc analyses found that 5 of 6 components of bicultural competence used as outcome variables supported the moderation mediation hypotheses. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

[Mediation in schools].

Science.gov (United States)

Mickley, Angela

2006-01-01

In this article the guiding questions concern the objectives and effectiveness of introducing mediation into an existing school culture of dominance, competition and selection. In addition the necessity will be shown of combining conflict resolution with organisational development and the introduction of a consensual ethics and behaviour code to attain sustainable results in creating a constructive and healthy school environment. Given scarce resources and little time the decisive role of artistic methods will be looked at in providing young people with flexible methods of expressing and negotiating their interests in a changing environment of values and power structures. Some aspects of the development of nonviolent communication, conflict resolution and mediation methods in schools in Germany will be focused on with special emphasis on the type of intervention used and its long term sustainable effects.

Atmospheric ions and probable indirect biological effect of low-level radiation

International Nuclear Information System (INIS)

Spurny, Z.

1984-01-01

The problem is discussed of the health consequences of low radiation doses (of less than 0.01 Gy). Owing to natural radioactivity and cosmic radiation, ions are formed in the atmosphere which may thus indirectly mediate the effects of ionizing radiation on the organism. The rate of ion formation is approximately 6.1 ion pairs/cm 3 .s and their number will not exceed 10 3 ions/cm 3 . In an environment where artificial radioactive sources are used, the ion concentration may reach up to 10 5 ions/cm 3 . The effect of ions on man may be divided into several types: 1. effect on mental state (behaviour, fatigue, headaches); 2. effect on the cardiovascular system; 3. effect on the bronchial system;and 4. effect on physiological processes, e.g., secretion by endocrine glands. It is not yet known whether the biological effect of small (fast) ions is a function of their electric charge only or of their kinetic energy as well. The view is discussed that low radiation doses through indirect effects have favourable and beneficial influence on the human organism. (M.D.)

Pedal indirect lymphangiography

International Nuclear Information System (INIS)

Lee, Kil Woo; Hong, Myung Sun; Kim, In Jae

1994-01-01

Recently, indirect lymphangiography has been developed as a relatively good and noninvasive imaging modality of the lymphatic system at extremities. But the disadvantage of the indirect lymphangiography is a low contrast ratio between the surrounding tissues and the contrast media in lymphatic vessels, because dimeric nonionic contrast media is water soluble and diluted in the proximal leg lymphatic vessels. We could have relatively better image than previously published images for the leg lymphatic system, when we injected contrast media with adequate high pressure in intradermal space of the interdigital areas at the foot dorsum. So, we would like to report the results. We could study all 9 lymphedemas(primary: 6, secondary: 3) from April 1990 to May 1993 on outpatient base. They were diagnosed as lymphedema clinically and radiologically. Ten ml of dimeric nonionic aget, iotrolan(Isovist 300) was injected into intradermal space with five 30-gauge needles. The injection speed was more than 0.2 ml/min. We have done one side pedal lymphangiogram in 30 minutes. The evaluation of the anterior superficial lymphatics was according to the criteria of the Weissleder. The results were as follows: 1. All lymphatic vessels from foot to inguinal area could be visualized. 2. Two or three inferior inguinal lymph nodes could be visualized about 42%. 3. The most common abnormal finding of the lymphedma was the neovascularization of the lymphatics on indirect pedal lymphangiogram. If we use adequate technique relatively high pressure injection, correct intradermal needle insertion, adequate soft tissue exposure technique indirect lymphangiography is considered to be a safe and noninvasive imaging modality for the evaluation of the lymphedema of lower extremity lymphatics including inferior inguinal lymph nodes

Competitive balance in national European soccer competitions

NARCIS (Netherlands)

Haan, M.A.; Koning, R.H.; van Witteloostuijn, A.; Albert, Jim; Koning, Ruud H.

2007-01-01

According to popular belief, competitive balance in national soccer competitions in Europe has decreased due to the Bosman ruling and the introduction of the Champions League. We test this hypothesis using data from 7 national competitions, for a host of indicators. We find some evidence for

How do psychological factors influence adolescent smoking progression? The evidence for indirect effects through tobacco advertising receptivity.

Science.gov (United States)

Audrain-McGovern, Janet; Rodriguez, Daniel; Patel, Vaishali; Faith, Myles S; Rodgers, Kelli; Cuevas, Jocelyn

2006-04-01

To determine whether novelty seeking and depressive symptoms had mediated or indirect effects on adolescent smoking progression through tobacco advertising receptivity. More than 1000 adolescents were monitored from 9th grade to 12th grade and completed annual surveys that measured demographic characteristics, smoking behavior, tobacco advertising receptivity, novelty-seeking personality, depressive symptoms, family and peer smoking, alcohol use, and marijuana use. Latent growth modeling indicated that novelty seeking had a significant indirect effect on smoking progression through baseline tobacco advertising receptivity. For each 1-SD increase in novelty seeking, the odds of being more receptive to tobacco advertising increased by 12% (ie, being in a specific category or higher), which in turn resulted in an 11% increase in the odds of smoking progression from 9th grade to 12th grade. The indirect effect from depressive symptoms to smoking progression did not reach significance. These findings may inform future research on other factors that influence tobacco advertising receptivity, as well as programs aimed at preventing adolescent smoking initiation and progression.

Acer negundo invasion along a successional gradient: early direct facilitation by native pioneers and late indirect facilitation by conspecifics.

Science.gov (United States)

Saccone, Patrick; Pagès, Jean-Philippe; Girel, Jacky; Brun, Jean-Jacques; Michalet, Richard

2010-08-01

*Here, we analysed the role of direct and indirect plant interactions in the invasion process of Acer negundo along a natural successional gradient in the Middle Rhone floodplain (France). We addressed two questions: What are the responses of the invasive Acer seedlings to native communities' effects along the successional gradient? What are the effects of the invasive Acer adult trees on the native communities? *In the three communities (Salix, Acer and Fraxinus stands) we transplanted juveniles of the invasive and juveniles of the natives within the forest and in experimental gaps, and with and without the herb layer. We also quantified changes in understory functional composition, light, nitrogen and moisture among treatments. *Acer seedlings were directly facilitated for survival in the Salix and Acer communities and indirectly facilitated for growth by adult Acer through the reduction of the abundance of highly competitive herbaceous competitors. *We conclude that direct facilitation by the tree canopy of the native pioneer Salix is very likely the main biotic process that induced colonization of the invasive Acer in the floodplain and that indirect facilitation by adult conspecifics contributed to population establishment.

Developing models of how cognitive improvements change functioning: Mediation, moderation and moderated mediation

Science.gov (United States)

Wykes, Til; Reeder, Clare; Huddy, Vyv; Taylor, Rumina; Wood, Helen; Ghirasim, Natalia; Kontis, Dimitrios; Landau, Sabine

2012-01-01

Background Cognitive remediation (CRT) affects functioning but the extent and type of cognitive improvements necessary are unknown. Aim To develop and test models of how cognitive improvement transfers to work behaviour using the data from a current service. Method Participants (N49) with a support worker and a paid or voluntary job were offered CRT in a Phase 2 single group design with three assessments: baseline, post therapy and follow-up. Working memory, cognitive flexibility, planning and work outcomes were assessed. Results Three models were tested (mediation — cognitive improvements drive functioning improvement; moderation — post treatment cognitive level affects the impact of CRT on functioning; moderated mediation — cognition drives functioning improvements only after a certain level is achieved). There was evidence of mediation (planning improvement associated with improved work quality). There was no evidence that cognitive flexibility (total Wisconsin Card Sorting Test errors) and working memory (Wechsler Adult Intelligence Scale III digit span) mediated work functioning despite significant effects. There was some evidence of moderated mediation for planning improvement if participants had poorer memory and/or made fewer WCST errors. The total CRT effect on work quality was d = 0.55, but the indirect (planning-mediated CRT effect) was d = 0.082 Conclusion Planning improvements led to better work quality but only accounted for a small proportion of the total effect on work outcome. Other specific and non-specific effects of CRT and the work programme are likely to account for some of the remaining effect. This is the first time complex models have been tested and future Phase 3 studies need to further test mediation and moderated mediation models. PMID:22503640

Competitive ability, stress tolerance and plant interactions along stress gradients.

Science.gov (United States)

Qi, Man; Sun, Tao; Xue, SuFeng; Yang, Wei; Shao, DongDong; Martínez-López, Javier

2018-04-01

Exceptions to the generality of the stress-gradient hypothesis (SGH) may be reconciled by considering species-specific traits and stress tolerance strategies. Studies have tested stress tolerance and competitive ability in mediating interaction outcomes, but few have incorporated this to predict how species interactions shift between competition and facilitation along stress gradients. We used field surveys, salt tolerance and competition experiments to develop a predictive model interspecific interaction shifts across salinity stress gradients. Field survey and greenhouse tolerance tests revealed tradeoffs between stress tolerance and competitive ability. Modeling showed that along salinity gradients, (1) plant interactions shifted from competition to facilitation at high salinities within the physiological limits of salt-intolerant plants, (2) facilitation collapsed when salinity stress exceeded the physiological tolerance of salt-intolerant plants, and (3) neighbor removal experiments overestimate interspecific facilitation by including intraspecific effects. A community-level field experiment, suggested that (1) species interactions are competitive in benign and, facilitative in harsh condition, but fuzzy under medium environmental stress due to niche differences of species and weak stress amelioration, and (2) the SGH works on strong but not weak stress gradients, so SGH confusion arises when it is applied across questionable stress gradients. Our study clarifies how species interactions vary along stress gradients. Moving forward, focusing on SGH applications rather than exceptions on weak or nonexistent gradients would be most productive. © 2018 by the Ecological Society of America.

Two facets of stress and indirect effects on child diet through emotion-driven eating.

Science.gov (United States)

Tate, Eleanor B; Spruijt-Metz, Donna; Pickering, Trevor A; Pentz, Mary Ann

2015-08-01

Stress has been associated with high-calorie, low-nutrient food intake (HCLN) and emotion-driven eating (EDE). However, effects on healthy food intake remain unknown. This study examined two facets of stress (self-efficacy, perceived helplessness) and food consumption, mediated by EDE. Cross-sectional data from fourth-graders (n=978; 52% female, 28% Hispanic) in an obesity intervention used self-report to assess self-efficacy, helplessness, EDE, fruit/vegetable (FV) intake, and high-calorie/low-nutrient (HCLN) food. Higher stress self-efficacy was associated with higher FV intake, β=.354, pstress perceived helplessness had an indirect effect on HCLN intake through emotion-driven eating, indirect effect=.094, pStress self-efficacy may be more important for healthy food intake and perceived helplessness may indicate emotion-driven eating and unhealthy snack food intake. Obesity prevention programs may consider teaching stress management techniques to avoid emotion-driven eating. Copyright © 2015 Elsevier Ltd. All rights reserved.

Does interspecific competition have a moderating effect on Taenia solium transmission dynamics in Southeast Asia?

Science.gov (United States)

Conlan, James V; Vongxay, Khamphouth; Fenwick, Stanley; Blacksell, Stuart D; Thompson, R C Andrew

2009-09-01

It is well understood that sociocultural practices strongly influence Taenia solium transmission; however, the extent to which interspecific parasite competition moderates Taenia transmission has yet to be determined. This is certainly the case in Southeast Asia where T. solium faces competition in both the definitive host (people) and the intermediate host (pigs). In people, adult worms of T. solium, T. saginata and T. asiatica compete through density-dependent crowding mechanisms. In pigs, metacestodes of T. solium, T. hydatigena and T. asiatica compete through density-dependent immune-mediated interactions. Here, we describe the biological and epidemiological implications of Taenia competition and propose that interspecific competition has a moderating effect on the transmission dynamics of T. solium in the region. Furthermore, we argue that this competitive ecological scenario should be considered in future research and surveillance activities examining T. solium cysticercosis and taeniasis in Southeast Asia.

Supersymmetric dark matter: Indirect detection

International Nuclear Information System (INIS)

Bergstroem, L.

2000-01-01

Dark matter detection experiments are improving to the point where they can detect or restrict the primary particle physics candidates for non baryonic dark matter. The methods for detection are usually categorized as direct, i.e., searching for signals caused by passage of dark matter particles in terrestrial detectors, or indirect. Indirect detection methods include searching for antimatter and gamma rays, in particular gamma ray lines, in cosmic rays and high-energy neutrinos from the centre of the Earth or Sun caused by accretion and annihilation of dark matter particles. A review is given of recent progress in indirect detection, both on the theoretical and experimental side

INDIRECT LABOR COSTS AND IMPLICATIONS FOR OVERHEAD ALLOCATION

OpenAIRE

Bea Chiang

2013-01-01

Cost accounting typically allocates indirect labor cost to cost object based on direct labor hours. The allocation process implicitly assumes that indirect labor costs vary proportionally with direct labor hours. The assumption of a linear relationship between indirect and direct labor is particularly suspicious at low production volume levels because there tends to be a fixed component in indirect labor. The linearity assumption is also challenged by recent increasing complexity of indirect ...

Relationship between mediation analysis and the structured life course approach

Science.gov (United States)

Howe, Laura D; Smith, Andrew D; Macdonald-Wallis, Corrie; Anderson, Emma L; Galobardes, Bruna; Lawlor, Debbie A; Ben-Shlomo, Yoav; Hardy, Rebecca; Cooper, Rachel; Tilling, Kate; Fraser, Abigail

2016-01-01

Abstract Many questions in life course epidemiology involve mediation and/or interaction because of the long latency period between exposures and outcomes. In this paper, we explore how mediation analysis (based on counterfactual theory and implemented using conventional regression approaches) links with a structured approach to selecting life course hypotheses. Using theory and simulated data, we show how the alternative life course hypotheses assessed in the structured life course approach correspond to different combinations of mediation and interaction parameters. For example, an early life critical period model corresponds to a direct effect of the early life exposure, but no indirect effect via the mediator and no interaction between the early life exposure and the mediator. We also compare these methods using an illustrative real-data example using data on parental occupational social class (early life exposure), own adult occupational social class (mediator) and physical capability (outcome). PMID:27681097

Host age modulates within-host parasite competition.

Science.gov (United States)

Izhar, Rony; Routtu, Jarkko; Ben-Ami, Frida

2015-05-01

In many host populations, one of the most striking differences among hosts is their age. While parasite prevalence differences in relation to host age are well known, little is known on how host age impacts ecological and evolutionary dynamics of diseases. Using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pasteuria ramosa, we examined how host age at exposure influences within-host parasite competition and virulence. We found that multiply-exposed hosts were more susceptible to infection and suffered higher mortality than singly-exposed hosts. Hosts oldest at exposure were least often infected and vice versa. Furthermore, we found that in young multiply-exposed hosts competition was weak, allowing coexistence and transmission of both parasite clones, whereas in older multiply-exposed hosts competitive exclusion was observed. Thus, age-dependent parasite exposure and host demography (age structure) could together play an important role in mediating parasite evolution. At the individual level, our results demonstrate a previously unnoticed interaction of the host's immune system with host age, suggesting that the specificity of immune function changes as hosts mature. Therefore, evolutionary models of parasite virulence might benefit from incorporating age-dependent epidemiological parameters. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Frequency and direction of competitive anger in contact sports.

Science.gov (United States)

Robazza, B; Bertollo, M; Bortoli, L

2006-09-01

The purpose of the present study was to investigate whether athletes involved in physical contact sports may interpret their feelings of anger as facilitative of performance, and to examine differences in the interpretation of anger as a function of the type of sport (team vs individual) or the competitive skill level (high vs low). A modified version of the State-Trait Anger Expression Inventory was administered to 100 Italian adult male athletes practicing rugby or individual combat sports (judo, freestyle wrestling, or Greco-Roman wrestling). The questionnaire was intended to measure the frequency and the direction (i.e., the facilitative-debilitative interpretation) of competitive anger. Many athletes engaged in contact sports tended interpret their competitive anger as facilitative of performance rather than debilitative. The type of sport and the athlete's standard level can mediate the individual's interpretation of the effects of anger symptoms upon performance. Competitors can interpret their anger as helpful to energize behavior and channel physical and mental resources for skill execution. Practitioners should assist athletes in gaining control over anger rather than attempting to suppress it.

Hubungan antara Knowledge-Technology-Innovation (KTI, Commitment, Competence, Leadership, Government Policy, Human Capital, dan Competitive Advantage

Directory of Open Access Journals (Sweden)

Darjat Sudrajat

2014-05-01

Full Text Available In current tight competitive situation, companies always try to create differentiation anytime to achieve better and sustainable performance. Rapid and unpredictable changes insist the companies should always be innovative, so that aspects of globalization, e-business, technology innovation, creativity, global competition, knowledge creation, diffusion of new technologies and knowledge revolution should be sources of performance and competitiveness improvement. Therefore, tomaintain core competencies and competitive advantage, the companies should develop continuous innovation, technologylearning, and knowledge management. Knowledge-Technology-Innovation (KTI can be a driver for country’s development and growth. Japan, South Korea, and Singapore are the countries that have limited natural and human resources, but able to achieve sustainable economic development. KTI is not only to be practiced at individual and organizational level, but also can be implemented at the community, national, or state level. KTI, therefore, can encourage expected competitive advantage creation and become a decisive factor for a country to achieve stable and sustainable economic growth. This research intends to analyze relationships of KTI, competitive advantage, commitment, leadership, human capital, government policy,and competence. This research used correlational method and literature study approach. The result of this research is a relationship model of each of these aspects that can be used as a framework for further research. The relationships model isas follows: Leadership, competence, and human capital (as independent variables have direct relationship (influence oncompetitive advantage (dependent variable or indirectly (through KTI as an intervening variable; KTI has direct relationship (effect on competitive advantage; Government policy and commitment are moderator variables for relationshipof KTI and competitive advantage.

Direct and indirect controls on organic matter decomposition in four coastal wetland communities along a landscape salinity gradient

Science.gov (United States)

Stagg, Camille L.; Baustian, Melissa M.; Perry, Carey L.; Carruthers, Tim J.B.; Hall, Courtney T.

2018-01-01

Coastal wetlands store more carbon than most ecosystems globally. As sea level rises, changes in flooding and salinity will potentially impact ecological functions, such as organic matter decomposition, that influence carbon storage. However, little is known about the mechanisms that control organic matter loss in coastal wetlands at the landscape scale. As sea level rises, how will the shift from fresh to salt-tolerant plant communities impact organic matter decomposition? Do long-term, plant-mediated, effects of sea-level rise differ from direct effects of elevated salinity and flooding?We identified internal and external factors that regulated indirect and direct pathways of sea-level rise impacts, respectively, along a landscape-scale salinity gradient that incorporated changes in wetland type (fresh, oligohaline, mesohaline and polyhaline marshes). We found that indirect and direct impacts of sea-level rise had opposing effects on organic matter decomposition.Salinity had an indirect effect on litter decomposition that was mediated through litter quality. Despite significant variation in environmental conditions along the landscape gradient, the best predictors of above- and below-ground litter decomposition were internal drivers, initial litter nitrogen content and initial litter lignin content respectively. Litter decay constants were greatest in the oligohaline marsh and declined with increasing salinity, and the fraction of litter remaining (asymptote) was greatest in the mesohaline marsh. In contrast, direct effects of salinity and flooding were positive. External drivers, salinity and flooding, stimulated cellulytic activity, which was highest in the polyhaline marsh.Synthesis. Our results indicate that as sea level rises, initial direct effects of salinity will stimulate decay of labile carbon, but over time as plant communities shift from fresh to polyhaline marsh, litter decay will decline, yielding greater potential for long-term carbon storage

Interactive and Indirect Effects of Anxiety and Negative Urgency on Alcohol-Related Problems

Science.gov (United States)

Menary, Kyle R.; Corbin, William R.; Leeman, Robert F.; Fucito, Lisa M.; Toll, Benjamin A.; DeMartini, Kelly; O’Malley, Stephanie S.

2015-01-01

Background Although drinking for tension reduction has long been posited as a risk factor for alcohol-related problems, studies investigating anxiety in relation to risk for alcohol problems have returned inconsistent results, leading researchers to search for potential moderators. Negative urgency (the tendency to become behaviorally dysregulated when experiencing negative affect) is a potential moderator of theoretical interest because it may increase risk for alcohol problems among those high in negative affect. The present study tested a cross-sectional mediated moderation hypothesis whereby an interactive effect of anxiety and negative urgency on alcohol problems is mediated through coping-related drinking motives. Method The study utilized baseline data from a hazardously drinking sample of young adults (N = 193) evaluated for participation in a randomized controlled trial of naltrexone and motivational interviewing for drinking reduction. Results The direct effect of anxiety on physiological dependence symptoms was moderated by negative urgency such that the positive association between anxiety and physiological dependence symptoms became stronger as negative urgency increased. Indirect effects of anxiety and negative urgency on alcohol problems (operating through coping motives) were also observed. Conclusions Although results of the current cross-sectional study require replication using longitudinal data, the findings suggest that the simultaneous presence of anxiety and negative urgency may be an important indicator of risk for AUDs via both direct interactive effects and indirect additive effects operating through coping motives. These findings have potentially important implications for prevention/intervention efforts for individuals who become disinhibited in the context of negative emotional states. PMID:26031346

Reflections on Competition, Competition Regulation and the Current Crises

DEFF Research Database (Denmark)

Buch-Hansen, Hubert; Wigger, Angela

2013-01-01

competition came to enjoy such an exalted status in Europe and then challenges conventional wisdom by bringing into focus the downsides of competition. It argues that excessive competition and neoliberal competition regulation have contributed to intensify the economic, political, social and environmental...

Common region wins the competition between extrinsic grouping cues: Evidence from a task without explicit attention to grouping.

Science.gov (United States)

Montoro, Pedro R; Villalba-García, Cristina; Luna, Dolores; Hinojosa, José A

2017-12-01

The competition between perceptual grouping factors is a relatively ignored topic, especially in the case of extrinsic grouping cues (e.g., common region or connectedness). Recent studies have examined the integration of extrinsic cues using tasks that induce selective attention to groups based on different grouping cues. However, this procedure could generate alternative strategies for task performance, which are non-related to the perceptual grouping operations. In the current work, we used an indirect task, i.e. repetition discrimination task, without explicit attention to grouping cues to further examine the rules that govern dominance between competing extrinsic grouping factors. This procedure allowed us to obtain an unbiased measure of the competition between common region and connectedness cues acting within the same display. The results corroborate previous data showing that grouping by common region dominated the perceived organization of the display, even though the phenomenological strength of the grouping cues was equated for each participant by means of a preliminary scaling task. Our results highlight the relevance of using indirect tasks as an essential tool for the systematic study of the integration of extrinsic grouping cues.

Analysis of indirect taxation in Ukraine

Directory of Open Access Journals (Sweden)

Khodyakova Olga V.

2014-01-01

Full Text Available The goal of the article is analysis of the structure and dynamics of indirect taxes for the previous five years and also the influence of indirect taxation upon formation of income of the State Budget of Ukraine. The article analyses the modern state of indirect taxation in Ukraine. Specific weight of the value added tax, excise tax and customs duty are considered in the structure of tax receipts of the consolidated budget of Ukraine as indirect taxes. The article shows that receipts of the State Budget of Ukraine are mostly provided by indirect taxes. The Ukrainian taxation system is mostly a factor of reduction of the level of economic growth and investment activity in the country and the existing system of administering is not completely capable of excluding the possibility of tax evasion. The prospect of further studies in this direction is improvement of organisation of tax control in Ukraine and differentiation of the value added tax rates depending on the level of consumption of goods and level of income of consumers.

Modelling Knowledge Sharing Behaviour Using Self-Efficacy as a Mediator

Science.gov (United States)

Brooke, Jenefer; Mohd Rasdi, Roziah; Abu Samah, Bahaman

2017-01-01

Purpose: The purpose of this paper is to examine the direct and indirect relationships between individual-related factors and environmental-related factors with the knowledge sharing behaviour through the mediating role of self-efficacy among successful farmers in selected states in Malaysia. Design/methodology/approach: The research used survey…

Allelopathy and resource competition: the effects of Phragmites australis invasion in plant communities.

Science.gov (United States)

Uddin, Md Nazim; Robinson, Randall William

2017-12-01

Phragmites australis, a ubiquitous wetland plant, has been considered one of the most invasive species in the world. Allelopathy appears to be one of the invasion mechanisms, however, the effects could be masked by resource competition among target plants. The difficulty of distinguishing allelopathy from resource competition among plants has hindered investigations of the role of phytotoxic allelochemicals in plant communities. This has been addressed via experiments conducted in both the greenhouse and laboratory by growing associated plants, Melaleuca ericifolia, Rumex conglomeratus, and model plant, Lactuca sativa at varying densities with the allelopathic plant, P. australis, its litter and leachate of P. australis litter. This study investigated the potential interacting influences of allelopathy and resource competition on plant growth-density relationships. In greenhouse, the root exudates mediated effects showed the strongest growth inhibition of M. ericifolia at high density whereas litter mediated results revealed increased growth at medium density treatments compared to low and high density. Again, laboratory experiments related to seed germination and seedling growth of L. sativa and R. conglomeratus exhibited phytotoxicity decreased showing positive growth as plant density increased and vice versa. Overall, the differential effects were observed among experiments but maximum individual plant biomass and some other positive effects on plant traits such as root and shoot length, chlorophyll content occurred at an intermediate density. This was attributed to the sharing of the available phytotoxin among plants at high densities which is compatible to density-dependent phytotoxicity model. The results demonstrated that plant-plant interference is the combined effect of allelopathy and resource competition with many other factors but this experimental design, target-neighbor mixed-culture in combination of plant grown at varying densities with varying

Wake up and smell the conflict: odour signals in female competition

Science.gov (United States)

Stockley, Paula; Bottell, Lisa; Hurst, Jane L.

2013-01-01

Odour signals used in competitive and aggressive interactions between males are well studied in the context of sexual selection. By contrast, relatively little is known about comparable signals used by females, despite current interest in the evolution of female ornaments and weaponry. Available evidence suggests that odour signals are important in competitive interactions between female mammals, with reductions or reversals of male-biased sexual dimorphism in signalling where female competition is intense. Scent marking is often associated with conflict between females over access to resources or reproductive opportunities. Female scent marks may therefore provide reliable signals of competitive ability that could be used both by competitors and potential mates. Consistent with this hypothesis, we report that aggressive behaviour of female house mice is correlated with the amount of major urinary protein (MUP) excreted in their urine, a polymorphic set of proteins that are used in scent mark signalling. Under semi-natural conditions, females with high MUP output are more likely to produce offspring sired by males that have high reproductive success, and less likely to produce offspring by multiple different sires, suggesting that females with strong MUP signals are monopolized by males of particularly high quality. We conclude that odour signals are worthy of more detailed investigation as mediators of female competition. PMID:24167312

Childhood abuse and psychotic experiences - evidence for mediation by adulthood adverse life events.

Science.gov (United States)

Bhavsar, V; Boydell, J; McGuire, P; Harris, V; Hotopf, M; Hatch, S L; MacCabe, J H; Morgan, C

2017-10-09

We have previously reported an association between childhood abuse and psychotic experiences (PEs) in survey data from South East London. Childhood abuse is related to subsequent adulthood adversity, which could form one pathway to PEs. We aimed to investigate evidence of mediation of the association between childhood abuse and PEs by adverse life events. Data were analysed from the South East London Community Health Study (SELCoH, n = 1698). Estimates of the total effects on PEs of any physical or sexual abuse while growing up were partitioned into direct (i.e. unmediated) and indirect (total and specific) effects, mediated via violent and non-violent life events. There was strong statistical evidence for direct (OR 1.58, 95% CI: 1.19-2.1) and indirect (OR 1.51, 95% CI: 1.32-1.72) effects of childhood abuse on PEs after adjustment for potential confounders, indicating partial mediation of this effect via violent and non-violent life events. An estimated 47% of the total effect of abuse on PEs was mediated via adulthood adverse life events, of which violent life events made up 33% and non-violent life events the remaining 14%. The association between childhood abuse and PEs is partly mediated through the experience of adverse life events in adulthood. There is some evidence that a larger proportion of this effect was mediated through violent life events than non-violent life events.

Environmental structure and competitive scoring advantages in team competitions

Science.gov (United States)

Merritt, Sears; Clauset, Aaron

2013-10-01

In most professional sports, playing field structure is kept neutral so that scoring imbalances may be attributed to differences in team skill. It thus remains unknown what impact environmental heterogeneities can have on scoring dynamics or competitive advantages. Applying a novel generative model of scoring dynamics to roughly 10 million team competitions drawn from an online game, we quantify the relationship between the structure within a competition and its scoring dynamics, while controlling the impact of chance. Despite wide structural variations, we observe a common three-phase pattern in the tempo of events. Tempo and balance are highly predictable from a competition's structural features alone and teams exploit environmental heterogeneities for sustained competitive advantage. Surprisingly, the most balanced competitions are associated with specific environmental heterogeneities, not from equally skilled teams. These results shed new light on the design principles of balanced competition, and illustrate the potential of online game data for investigating social dynamics and competition.

Evidence of chemical stimulation of hepatic metabolism by an experimental acetanilide (FOE 5043) indirectly mediating reductions in circulating thyroid hormone levels in the male rat.

Science.gov (United States)

Christenson, W R; Becker, B D; Wahle, B S; Moore, K D; Dass, P D; Lake, S G; Van Goethem, D L; Stuart, B P; Sangha, G K; Thyssen, J H

1996-02-01

N-(4-Fluorophenyl)-N-(1-methylethyl)-2-[[5-(trifluoromethyl)-1,3, 4-thiadiazol-2-yl]oxy]acetamide (FOE 5043) is a new acetanilide-type herbicide undergoing regulatory testing. Previous work in this laboratory suggested that FOE 5043-induced reductions in serum thyroxine (T4) levels were mediated via an extrathyroidal site of action. The possibility that the alterations in circulating T4 levels were due to chemical induction of hepatic thyroid hormone metabolism was investigated. Treatment with FOE 5043 at a rate of 1000 ppm as a dietary admixture was found to significantly increase the clearance of [125I]T4 from the serum, suggesting an enhanced excretion of the hormone. In the liver, the activity of hepatic uridine glucuronosyl transferase, a major pathway of thyroid hormone biotransformation in the rat, increased in a statistically significant and dose-dependent manner; conversely, hepatic 5'-monodeiodinase activity trended downward with dose. Bile flow as well as the hepatic uptake and biliary excretion of [125I]T4 were increased following exposure to FOE 5043. Thyroidal function, as measured by the discharge of iodide ion in response to perchlorate, and pituitary function, as measured by the capacity of the pituitary to secrete thyrotropin in response to an exogenous challenge by hypothalamic thyrotropin releasing hormone, were both unchanged from the controlled response. These data suggest that the functional status of the thyroid and pituitary glands has not been altered by treatment with FOE 5043 and that reductions in circulating levels of T4 are being mediated indirectly through an increase in the biotransformation and excretion of thyroid hormone in the liver.

The role of adaptations in two-strain competition for sylvatic Trypanosoma cruzi transmission.

Science.gov (United States)

Kribs-Zaleta, Christopher M; Mubayi, Anuj

2012-01-01

This study presents a continuous-time model for the sylvatic transmission dynamics of two strains of Trypanosoma cruzi enzootic in North America, in order to study the role that adaptations of each strain to distinct modes of transmission (classical stercorarian transmission on the one hand, and vertical and oral transmission on the other) may play in the competition between the two strains. A deterministic model incorporating contact process saturation predicts competitive exclusion, and reproductive numbers for the infection provide a framework for evaluating the competition in terms of adaptive trade-off between distinct transmission modes. Results highlight the importance of oral transmission in mediating the competition between horizontal (stercorarian) and vertical transmission; its presence as a competing contact process advantages vertical transmission even without adaptation to oral transmission, but such adaptation appears necessary to explain the persistence of (vertically-adapted) T. cruzi IV in raccoons and woodrats in the southeastern United States.

Future Expectations, Attitude Toward Violence, and Bullying Perpetration During Early Adolescence: A Mediation Evaluation.

Science.gov (United States)

Stoddard, Sarah A; Varela, Jorge J; Zimmerman, Marc A

2015-01-01

Hopeful future expectations have been linked to positive developmental outcomes in adolescence; however, the association between future expectations and bullying perpetration has received less attention. We examined the relationship between future expectations and physical and relational bullying perpetration and tested a mediation model that linked future expectations with bullying through attitude toward violence. Structural equation modeling was used to examine the relationship between future expectations and bullying perpetration (relational and physical) and to test whether these relationships were mediated by attitude toward violence in a sample of U.S. seventh-grade students (Mage = 12.86 years, N = 196, 60% female, 46% African American). Attitude toward violence fully mediated the relationship between future expectations and physical bullying (indirect effects = -0.08, 95% CI [-0.15, -0.01], R = .17). The relationship between future expectations and relational bullying was partially mediated by attitudes toward violence (indirect effects = -0.07, 95% CI [-0.14, -0.002], R = .20). Our findings suggest that future expectations can play a role in reducing attitude toward violence and physical and relational bullying perpetration among youth. Interventions that help support the development of future goals and aspirations could play a vital role in bullying prevention efforts.

Granzyme B mediates both direct and indirect cleavage of extracellular matrix in skin after chronic low-dose ultraviolet light irradiation.

Science.gov (United States)

Parkinson, Leigh G; Toro, Ana; Zhao, Hongyan; Brown, Keddie; Tebbutt, Scott J; Granville, David J

2015-02-01

Extracellular matrix (ECM) degradation is a hallmark of many chronic inflammatory diseases that can lead to a loss of function, aging, and disease progression. Ultraviolet light (UV) irradiation from the sun is widely considered as the major cause of visible human skin aging, causing increased inflammation and enhanced ECM degradation. Granzyme B (GzmB), a serine protease that is expressed by a variety of cells, accumulates in the extracellular milieu during chronic inflammation and cleaves a number of ECM proteins. We hypothesized that GzmB contributes to ECM degradation in the skin after UV irradiation through both direct cleavage of ECM proteins and indirectly through the induction of other proteinases. Wild-type and GzmB-knockout mice were repeatedly exposed to minimal erythemal doses of solar-simulated UV irradiation for 20 weeks. GzmB expression was significantly increased in wild-type treated skin compared to nonirradiated controls, colocalizing to keratinocytes and to an increased mast cell population. GzmB deficiency significantly protected against the formation of wrinkles and the loss of dermal collagen density, which was related to the cleavage of decorin, an abundant proteoglycan involved in collagen fibrillogenesis and integrity. GzmB also cleaved fibronectin, and GzmB-mediated fibronectin fragments increased the expression of collagen-degrading matrix metalloproteinase-1 (MMP-1) in fibroblasts. Collectively, these findings indicate a significant role for GzmB in ECM degradation that may have implications in many age-related chronic inflammatory diseases. © 2014 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Depression and pain: testing of serial multiple mediators

Directory of Open Access Journals (Sweden)

Wongpakaran T

2016-07-01

function were found to significantly mediate the relationship between depression and pain, while controlling for demographic variables. The total effect of depression on pain was significant. This model, with an additional three mediators, accounted for 15% of the explained variance in pain compared to 9% without mediators. For the alternative model, after controlling for the mediators, a nonsignificant total direct effect level of self-sacrificing was found, suggesting that the effect of self-sacrificing on pain was based only on an indirect effect and that perceived stress was found to be the strongest mediator.Conclusion: Serial mediation may help us to see how depression and pain are linked and what the fundamental mediators are in the chain. No significant, indirect effect of self-sacrificing on pain was observed, if perceived stress was not part of the depression and/or cognitive function mediational chain. The results shown here have implications for future research, both in terms of testing the model and in clinical application. Keywords: depressive disorder, mediator, serial mediation, multiple mediation

A new hammer to crack an old nut: interspecific competitive resource capture by plants is regulated by nutrient supply, not climate.

Science.gov (United States)

Trinder, Clare J; Brooker, Rob W; Davidson, Hazel; Robinson, David

2012-01-01

Although rarely acknowledged, our understanding of how competition is modulated by environmental drivers is severely hampered by our dependence on indirect measurements of outcomes, rather than the process of competition. To overcome this, we made direct measurements of plant competition for soil nitrogen (N). Using isotope pool-dilution, we examined the interactive effects of soil resource limitation and climatic severity between two common grassland species. Pool-dilution estimates the uptake of total N over a defined time period, rather than simply the uptake of ¹⁵N label, as used in most other tracer experiments. Competitive uptake of N was determined by its available form (NO₃⁻ or NH₄⁺). Soil N availability had a greater effect than the climatic conditions (location) under which plants grew. The results did not entirely support either of the main current theories relating the role of competition to environmental conditions. We found no evidence for Tilman's theory that competition for soil nutrients is stronger at low, compared with high nutrient levels and partial support for Grime's theory that competition for soil nutrients is greater under potentially more productive conditions. These results provide novel insights by demonstrating the dynamic nature of plant resource competition.

A new hammer to crack an old nut: interspecific competitive resource capture by plants is regulated by nutrient supply, not climate.

Directory of Open Access Journals (Sweden)

Clare J Trinder

Full Text Available Although rarely acknowledged, our understanding of how competition is modulated by environmental drivers is severely hampered by our dependence on indirect measurements of outcomes, rather than the process of competition. To overcome this, we made direct measurements of plant competition for soil nitrogen (N. Using isotope pool-dilution, we examined the interactive effects of soil resource limitation and climatic severity between two common grassland species. Pool-dilution estimates the uptake of total N over a defined time period, rather than simply the uptake of ¹⁵N label, as used in most other tracer experiments. Competitive uptake of N was determined by its available form (NO₃⁻ or NH₄⁺. Soil N availability had a greater effect than the climatic conditions (location under which plants grew. The results did not entirely support either of the main current theories relating the role of competition to environmental conditions. We found no evidence for Tilman's theory that competition for soil nutrients is stronger at low, compared with high nutrient levels and partial support for Grime's theory that competition for soil nutrients is greater under potentially more productive conditions. These results provide novel insights by demonstrating the dynamic nature of plant resource competition.

Direct and indirect drivers of instream wood in the interior Pacific Northwest, USA: decoupling climate, vegetation, disturbance, and geomorphic setting

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Hough-Snee Nate

2014-06-01

Full Text Available Instream wood is a driver of geomorphic change in low-order streams, frequently altering morphodynamic processes. Instream wood is a frequently measured component of streams, yet it is a complex metric, responding to ecological and geomorphic forcings at a variety of scales. Here we seek to disentangle the relative importance of physical and biological processes that drive wood growth and delivery to streams across broad spatial extents. In so doing, we ask two primary questions: (1 is riparian vegetation a composite variable that captures the indirect effects of climate and disturbance on instream wood dynamics? (2 What are the direct and indirect relationships between geomorphic setting, vegetation, climate, disturbance, and instream wood dynamics? We measured riparian vegetation composition and wood frequency and volume at 720 headwater reaches within the American interior Pacific Northwest. We used ordination to identify relationships between vegetation and environmental attributes, and subsequently built a structural equation model to identify how climate and disturbance directly affect vegetation composition and how vegetation and geomorphic setting directly affect instream wood volume and frequency. We found that large wood volume and frequency are directly driven by vegetation composition and positively correlated to wildfire, elevation, stream gradient, and channel bankfull width. Indicator species at reaches with high volumes of wood were generally long-lived, conifer trees that persist for extended durations once delivered to stream habitats. Wood dynamics were also indirectly mediated by factors that shape vegetation: wildfire, precipitation, elevation, and temperature. We conclude that wood volume and frequency are driven by multiple interrelated climatic, geomorphic, and ecological variables. Vegetation composition and geomorphic setting directly mediate indirect relationships between landscape environmental processes and instream

Indirect Reciprocity under Incomplete Observation

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Nakamura, Mitsuhiro; Masuda, Naoki

2011-01-01

Indirect reciprocity, in which individuals help others with a good reputation but not those with a bad reputation, is a mechanism for cooperation in social dilemma situations when individuals do not repeatedly interact with the same partners. In a relatively large society where indirect reciprocity is relevant, individuals may not know each other's reputation even indirectly. Previous studies investigated the situations where individuals playing the game have to determine the action possibly without knowing others' reputations. Nevertheless, the possibility that observers of the game, who generate the reputation of the interacting players, assign reputations without complete information about them has been neglected. Because an individual acts as an interacting player and as an observer on different occasions if indirect reciprocity is endogenously sustained in a society, the incompleteness of information may affect either role. We examine the game of indirect reciprocity when the reputations of players are not necessarily known to observers and to interacting players. We find that the trustful discriminator, which cooperates with good and unknown players and defects against bad players, realizes cooperative societies under seven social norms. Among the seven social norms, three of the four suspicious norms under which cooperation (defection) to unknown players leads to a good (bad) reputation enable cooperation down to a relatively small observation probability. In contrast, the three trustful norms under which both cooperation and defection to unknown players lead to a good reputation are relatively efficient. PMID:21829335

Direct and Indirect Effects of Climate Change on Amphibian Populations

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Stephanie S. Gervasi

2010-02-01

Full Text Available As part of an overall decline in biodiversity, populations of many organisms are declining and species are being lost at unprecedented rates around the world. This includes many populations and species of amphibians. Although numerous factors are affecting amphibian populations, we show potential direct and indirect effects of climate change on amphibians at the individual, population and community level. Shifts in amphibian ranges are predicted. Changes in climate may affect survival, growth, reproduction and dispersal capabilities. Moreover, climate change can alter amphibian habitats including vegetation, soil, and hydrology. Climate change can influence food availability, predator-prey relationships and competitive interactions which can alter community structure. Climate change can also alter pathogen-host dynamics and greatly influence how diseases are manifested. Changes in climate can interact with other stressors such as UV-B radiation and contaminants. The interactions among all these factors are complex and are probably driving some amphibian population declines and extinctions.

A Moderated Mediation Model for Board Diversity and Corporate Performance in ASEAN Countries

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Sahar E-Vahdati

2018-02-01

Full Text Available Despite the major investigations in prior studies for direct links among board diversity and corporate performance, the literature has not covered many indirect associations among them. This article analyzes the association between board diversity (gender and foreigner and corporate performance by focusing on the mediating role of corporate social responsibility reporting (CSRR and the moderated mediation role of South East Asian (ASEAN countries through new institutional theory, which consists of legitimacy and institutional theories. According to a sample of 264 corporates from all industries by using GRI G3 guideline from 2011 to 2013, we found that foreign and gender diversity have partial and full mediation effects in ASEAN countries. The main conclusion of the current article indicates that board diversity affects directly with corporate performance and indirectly with CSRR through moderated path analysis. The implications are valuable for academics, managers, and policy makers who are interested to determine the impact of intervening variables on the board diversity and corporate performance relationship in ASEAN countries.

Occupancy of yellow-billed and Pacific loons: evidence for interspecific competition and habitat mediated co-occurrence

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Haynes, Trevor B.; Schmutz, Joel A.; Lindberg, Mark S.; Wright, Kenneth G.; Uher-Koch, Brian D.; Rosenberger, Amanda E.

2014-01-01

Interspecific competition is an important process structuring ecological communities, however, it is difficult to observe in nature. We used an occupancy modelling approach to evaluate evidence of competition between yellow-billed (Gavia adamsii) and Pacific (G. pacifica) loons for nesting lakes on the Arctic Coastal Plain of Alaska. With multiple years of data and survey platforms, we estimated dynamic occupancy states (e.g. rates of colonization or extinction from individual lakes) and controlled for detection differences among aircraft platforms and ground survey crews. Results indicated that yellow-billed loons were strong competitors and negatively influenced the occupancy of Pacific loons by excluding them from potential breeding lakes. Pacific loon occupancy was conditional on the presence of yellow-billed loons, with Pacific loons having almost a tenfold decrease in occupancy probability when yellow-billed loons were present and a threefold decrease in colonization probability when yellow-billed loons were present in the current or previous year. Yellow-billed and Pacific loons co-occurred less than expected by chance except on very large lakes or lakes with convoluted shorelines; variables which may decrease the cost of maintaining a territory in the presence of the other species. These results imply the existence of interspecific competition between yellow-billed and Pacific loons for nesting lakes; however, habitat characteristics which facilitate visual and spatial separation of territories can reduce competitive interactions and promote species co-occurrence.

Involvement of Lgl and Mahjong/VprBP in cell competition.

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Yoichiro Tamori

2010-07-01

Full Text Available During the initial stages of carcinogenesis, transformation events occur in a single cell within an epithelial monolayer. However, it remains unknown what happens at the interface between normal and transformed epithelial cells during this process. In Drosophila, it has been recently shown that normal and transformed cells compete with each other for survival in an epithelial tissue; however the molecular mechanisms whereby "loser cells" undergo apoptosis are not clearly understood. Lgl (lethal giant larvae is a tumor suppressor protein and plays a crucial role in oncogenesis in flies and mammals. Here we have examined the involvement of Lgl in cell competition and shown that a novel Lgl-binding protein is involved in Lgl-mediated cell competition. Using biochemical immunoprecipitation methods, we first identified Mahjong as a novel binding partner of Lgl in both flies and mammals. In Drosophila, Mahjong is an essential gene, but zygotic mahjong mutants (mahj(-/- do not have obvious patterning defects during embryonic or larval development. However, mahj(-/- cells undergo apoptosis when surrounded by wild-type cells in the wing disc epithelium. Importantly, comparable phenomena also occur in Mahjong-knockdown mammalian cells; Mahjong-knockdown Madin-Darby canine kidney epithelial cells undergo apoptosis, only when surrounded by non-transformed cells. Similarly, apoptosis of lgl(-/- cells is induced when they are surrounded by wild-type cells in Drosophila wing discs. Phosphorylation of the c-Jun N-terminal kinase (JNK is increased in mahj(-/- or lgl(-/- mutant cells, and expression of Puckered (Puc, an inhibitor of the JNK pathway, suppresses apoptosis of these mutant cells surrounded by wild-type cells, suggesting that the JNK pathway is involved in mahj- or lgl-mediated cell competition. Finally, we have shown that overexpression of Mahj in lgl(-/- cells strongly suppresses JNK activation and blocks apoptosis of lgl(-/- cells in the wild

Ocean acidification affects competition for space: projections of community structure using cellular automata.

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McCoy, Sophie J; Allesina, Stefano; Pfister, Catherine A

2016-03-16

Historical ecological datasets from a coastal marine community of crustose coralline algae (CCA) enabled the documentation of ecological changes in this community over 30 years in the Northeast Pacific. Data on competitive interactions obtained from field surveys showed concordance between the 1980s and 2013, yet also revealed a reduction in how strongly species interact. Here, we extend these empirical findings with a cellular automaton model to forecast ecological dynamics. Our model suggests the emergence of a new dominant competitor in a global change scenario, with a reduced role of herbivory pressure, or trophic control, in regulating competition among CCA. Ocean acidification, due to its energetic demands, may now instead play this role in mediating competitive interactions and thereby promote species diversity within this guild. © 2016 The Author(s).

Comparison of monomeric and polymeric horseradish peroxidase as labels in competitive ELISA for small molecule detection

International Nuclear Information System (INIS)

Li, Dongyang; Ying, Yibin; Wu, Jian; Niessner, Reinhard; Knopp, Dietmar

2013-01-01

We have developed a simple and sensitive competitive enzyme-linked immunosorbent assay (ELISA) to determine aflatoxin B1 (as a model small analyte) and using streptavidin-polymeric horseradish peroxidase complex (SApolyHRP) as a label for signal amplification. The performance of the assay was evaluated by comparing it with the classical indirect competitive ELISA using HRP labeled anti-mouse IgG as the tracer antibody. The results indicate that the SApolyHRP-based competitive ELISA exhibits a typically 2.4-fold steeper slope of the linear working range of the calibration curve compared to the monomeric HRP based classical ELISA, i.e., the sensitivity was increased. The SApolyHRP conjugate causes a typically 19-fold stronger signal generation in comparison to the traditional HRP labeled anti-mouse IgG at the same concentration (25 ng mL −1 ). Moreover, the SApolyHRP-based assay has a much wider linear range and a 3.8-fold better signal-to-noise ratio. Considering its simplicity, sensitivity and ease of operation, this competitive ELISA is considered to be a promising tool for small molecule immuno detection. (author)

Relationship between mediation analysis and the structured life course approach.

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Howe, Laura D; Smith, Andrew D; Macdonald-Wallis, Corrie; Anderson, Emma L; Galobardes, Bruna; Lawlor, Debbie A; Ben-Shlomo, Yoav; Hardy, Rebecca; Cooper, Rachel; Tilling, Kate; Fraser, Abigail

2016-08-01

Many questions in life course epidemiology involve mediation and/or interaction because of the long latency period between exposures and outcomes. In this paper, we explore how mediation analysis (based on counterfactual theory and implemented using conventional regression approaches) links with a structured approach to selecting life course hypotheses. Using theory and simulated data, we show how the alternative life course hypotheses assessed in the structured life course approach correspond to different combinations of mediation and interaction parameters. For example, an early life critical period model corresponds to a direct effect of the early life exposure, but no indirect effect via the mediator and no interaction between the early life exposure and the mediator. We also compare these methods using an illustrative real-data example using data on parental occupational social class (early life exposure), own adult occupational social class (mediator) and physical capability (outcome). © The Author 2016. Published by Oxford University Press on behalf of the International Epidemiological Association.

Human Capital - A Quality Factor For The Competitiveness Of IT Companies

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Elisei Crăciun

2015-05-01

Full Text Available This paper treats quality, human capital and competitiveness concepts in order to determine in which measure the Human Capital quality influences the competitiveness of a firm. The human capital theory is a relatively new approach, the first valuable approach being that of Garry Becker which, subsequent of the modern management theoretical views, puts human capital into scientific frame. This present paper relates deeply on this theoretical frame as it is considered that, besides financial or tangible resources that allows and generate long term benefits for an enterprise, there is also another source that consists in an intangible form: the human capital. This resource is based on education and health, indirectly generating additional benefits for the individual as for the organization and is calculated as instruction, education and health insurances costs. That implies that this capital is an asset for the worker itself and that the worker cannot be distinguished from the knowledges, capacities, his health or his values. From this perspective, the worker is actively present in any activity a firm operates: from defining and executing process, operational planning, monitoring and control, research and development, human resources, etc. The hypothesis of this present paper will be explored with the examples of Jeff Bezos ( Amazon or Steve Jobs ( Apple as human capital is considered to be the most important component for the competitive advantage of IT enterprises. The quality level of the human capital represents the main source for long term sustainability of this competitive advantage and, given the best case practices, it’s impact on firm’s effect indicators is obvious. The paper will also emphasize the role of values and health as they are also the main issues on an IT enterprise. The article is structured in two parts. One is the theoretical frame that encompass the influence of the human capital on the competitiveness of the firm. The

An Indirect Route for Ethanol Production

Energy Technology Data Exchange (ETDEWEB)

Eggeman, T.; Verser, D.; Weber, E.

2005-04-29

The ZeaChem indirect method is a radically new approach to producing fuel ethanol from renewable resources. Sugar and syngas processing platforms are combined in a novel way that allows all fractions of biomass feedstocks (e.g. carbohydrates, lignins, etc.) to contribute their energy directly into the ethanol product via fermentation and hydrogen based chemical process technologies. The goals of this project were: (1) Collect engineering data necessary for scale-up of the indirect route for ethanol production, and (2) Produce process and economic models to guide the development effort. Both goals were successfully accomplished. The projected economics of the Base Case developed in this work are comparable to today's corn based ethanol technology. Sensitivity analysis shows that significant improvements in economics for the indirect route would result if a biomass feedstock rather that starch hydrolyzate were used as the carbohydrate source. The energy ratio, defined as the ratio of green energy produced divided by the amount of fossil energy consumed, is projected to be 3.11 to 12.32 for the indirect route depending upon the details of implementation. Conventional technology has an energy ratio of 1.34, thus the indirect route will have a significant environmental advantage over today's technology. Energy savings of 7.48 trillion Btu/yr will result when 100 MMgal/yr (neat) of ethanol capacity via the indirect route is placed on-line by the year 2010.

Retail competition

International Nuclear Information System (INIS)

1998-01-01

Retail competition as the cornerstone of a competitive electricity marketplace was the subject of the seventh in the series of policy discussion papers developed at the Market Design Conference. Concern was expressed that because of the complexities involved in market design and technical implementation, the retail competition may lag behind other elements of the implementation of the new market design. A variety of key issues were debated, including the role of physical versus financial contracts, the form of retail competition and financial settlement systems in the short term, the requirement to separate 'competitive' (metering, billing, maintenance, consumer education) from non-competitive' (the transmission wires) services and the role of municipal electric utilities. It was agreed that the IMO should play an important role in defining and enforcing the separation of services, and that as a general rule, the development of policy in this area should be guided by the principle of maximizing the potential for competition

Competitive intelligence as an enabler for firm competitiveness: An overview

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Alexander Maune

2014-06-01

Full Text Available The purpose of this article is to provide an overview, from literature, about how competitive intelligence can be an enabler towards a firm’s competitiveness. This overview is done under the background of intense global competition that firms are currently experiencing. This paper used a qualitative content analysis as a data collection methodology on all identified journal articles on competitive intelligence and firm competitiveness. To identify relevant literature, academic databases and search engines were used. Moreover, a review of references in related studies led to more relevant sources, the references of which were further reviewed and analysed. To ensure reliability and trustworthiness, peer-reviewed journal articles and triangulation were used. The paper found that competitive intelligence is an important enabler of firm competitiveness. The findings from this paper will assist business managers to understand and improve their outlook of competitive intelligence as an enabler of firm competitiveness and will be of great academic value.

Differential coding of reward and movement information in the dorsomedial striatal direct and indirect pathways.

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Shin, Jung Hwan; Kim, Dohoung; Jung, Min Whan

2018-01-26

The direct and indirect pathways of the basal ganglia have long been thought to mediate behavioral promotion and inhibition, respectively. However, this classic dichotomous model has been recently challenged. To better understand neural processes underlying reward-based learning and movement control, we recorded from direct (dSPNs) and indirect (iSPNs) pathway spiny projection neurons in the dorsomedial striatum of D1-Cre and D2-Cre mice performing a probabilistic Pavlovian conditioning task. dSPNs tend to increase activity while iSPNs decrease activity as a function of reward value, suggesting the striatum represents value in the relative activity levels of dSPNs versus iSPNs. Lick offset-related activity increase is largely dSPN selective, suggesting dSPN involvement in suppressing ongoing licking behavior. Rapid responses to negative outcome and previous reward-related responses are more frequent among iSPNs than dSPNs, suggesting stronger contributions of iSPNs to outcome-dependent behavioral adjustment. These findings provide new insights into striatal neural circuit operations.

SOCIAL COMPETENCE AND PSYCHOLOGICAL VULNERABILITY: THE MEDIATING ROLE OF FLOURISHING.

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Uysal, Recep

2015-10-01

This study examined whether flourishing mediated the social competence and psychological vulnerability. Participants were 259 university students (147 women, 112 men; M age = 21.3 yr., SD = 1.7) who completed the Turkish versions of the Perceived Social Competence Scale, the Flourishing Scale, and the Psychological Vulnerability Scale. Mediation models were tested using the bootstrapping method to examine indirect effects. Consistent with the hypotheses, the results indicated a positive relationship between social competence and flourishing, and a negative relationship between social competence and psychological vulnerability. Results of the bootstrapping method revealed that flourishing significantly mediated the relationship between social competence and psychological vulnerability. The significance and limitations of the results were discussed.

The Direct and Indirect Impact of Pharmaceutical Industry in Economic Expansion and Job Creation: Evidence from Bootstrapping and Normal Theory Methods

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Rizwan Raheem Ahmed

2018-05-01

Full Text Available The objective of this research article is to examine the role of Pakistan’s pharmaceutical industry in job creation opportunities, with the sacred intention to eradicate poverty, and expansion in economic activities. This research is quantitative in nature, and the data is directly gathered through closed-ended questionnaires from 300 respondents. Besides predictors’, four mediating variables have also been taken into consideration that contribute indirectly in job creation opportunities. Bootstrapping and Normal theory methods have been employed in order to examine the impact of predictors’ and mediating variables. The result of this research confirmed that pharmaceutical industry plays a vital role in job creation in Pakistan. It is further concluded that the pharmaceutical industry has a direct and significant impact in job creation by providing indigenous and direct job opportunities in sales, marketing, and other supporting departments for both skilled and unskilled workers. Pharmaceutical industry also provides indirect job opportunities through other industries, which are very much linked with this industry, such as: pharmaceutical distributors, dealers, retailers, wholesalers, hotel industry, and event management industry. It is also determined that pharmaceutical industry is acting like knowledge and skills imparting institutions. Therefore, skilled-based training and organizational learning are major mediating variables that transform unskilled people into human assets, which further trigger the future job prospects. Since pharmaceutical industry is one of the biggest industries in Pakistan, providing plenteous opportunities of new jobs with consistent growth. Thus, mediating variables such as motivation and interpersonal influence also preceded an active role in new job creation

Performance comparison of direct and indirect lighting systems

International Nuclear Information System (INIS)

Rubinstein, F.; Morse, O.; Clark, T.

1993-01-01

The performance of a retrofitted indirect lighting system was compared to the performance of a typical de-lamped direct lighting system in a partitioned office space. Power, illuminance and luminance measurements were made for the de-lamped direct lighting system and after installation of the indirect lighting system with various lamp and ballast combinations. Using the same lamps and ballasts, average workplace illuminance was slightly higher with indirect lighting than with direct lighting. With indirect lighting, workplace lumen efficacy was 4.5% lower due to the higher power draw of the lamps in the more open and cooler indirect fixtures. Indirect lighting with 36 watt T-8 lamps and electronic ballasts achieved an initial average workplace illuminance of 45 foot-candles in the partitioned office space at only 1.1 w/ft 2

Does Physical Self-Concept Mediate the Relationship between Motor Abilities and Physical Activity in Adolescents and Young Adults?

Science.gov (United States)

Jekauc, Darko; Wagner, Matthias Oliver; Herrmann, Christian; Hegazy, Khaled; Woll, Alexander

2017-01-01

The purpose of this study is to examine the reciprocal relationship between motor abilities and physical activity and the mediation effects of physical self-concept in this relationship using longitudinal data. We expect that the effects of motor abilities on physical activity are rather indirect via physical self-concept and that the effects of physical activity on motor abilities are rather direct without involvement of the motor ability self-concept. Data was obtained from the Motorik-Modul (MoMo) Longitudinal Study in which 335 boys and 363 girls aged 11–17 years old at Baseline were examined twice in a period of six years. Physical activity was assessed by the MoMo Physical Activity Questionnaire for adolescents, physical self-concept by Physical Self-Description Questionnaire and motor abilities by MoMo Motor Test which comprised of the dimensions strength, endurance, coordination and flexibility. Multiple regression analyses were used to analyse the direct and indirect effects. The results of the multiple regression analyses show that the effects of motor abilities on physical activity were only indirect for the dimensions strength, coordination, and flexibility. For the dimension endurance, neither direct nor indirect effects were significant. In the opposite direction, the effects of physical activity on motor abilities were partially mediated by the self-concept of strength. For the dimensions endurance, coordination and flexibility, only indirect were significant. The results of this study support the assumption that the relationship between motor abilities and physical activity is mediated by physical self-concept in both directions. Physical self-concept seems to be an important determinant of adolescents´ physical activity. PMID:28045914

The indirect effect of emotion dysregulation in terms of negative affect and smoking-related cognitive processes.

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Johnson, Adrienne L; McLeish, Alison C

2016-02-01

Although negative affect is associated with a number of smoking-related cognitive processes, the mechanisms underlying these associations have yet to be examined. The current study sought to examine the indirect effect of emotion regulation difficulties in terms of the association between negative affect and smoking-related cognitive processes (internal barriers to cessation, negative affect reduction smoking motives, negative affect reduction smoking outcome expectancies). Participants were 126 daily cigarette smokers (70.4% male, Mage=36.5years, SD=13.0; 69.8% Caucasian) who smoked an average of 18.5 (SD=8.7) cigarettes per day and reported moderate nicotine dependence. Formal mediation analyses were conducted using PROCESS to examine the indirect effect of negative affect on internal barriers to cessation and negative affect reduction smoking motives and outcome expectancies through emotion regulation difficulties. After accounting for the effects of gender, daily smoking rate, and anxiety sensitivity, negative affect was indirectly related to internal barriers to cessation and negative affect reduction smoking motives through emotion regulation difficulties. There was no significant indirect effect for negative affect reduction smoking outcome expectancies. These findings suggest that greater negative affect is associated with a desire to smoke to reduce this negative affect and perceptions that quitting smoking will be difficult due to negative emotions because of greater difficulties managing these negative emotions. Thus, emotion regulation difficulties may be an important target for smoking cessation interventions. Copyright © 2015 Elsevier Ltd. All rights reserved.

The role of temperament in the changes of coping in Type 2 diabetes: direct and indirect relationships

Directory of Open Access Journals (Sweden)

Kroemeke Aleksandra

2014-06-01

Full Text Available The paper investigates whether the changes in cognitive appraisal and coping strategies related to initiation of insulin treatment onset mediate the effect of temperament on changes in positivity ratio among diabetic patients. Temperament, cognitive appraisal, coping strategies and positivity ratio (ratio of positive to negative affect were assessed among 278 patients: just before conversion to insulin therapy and then one month later. Mediation analysis indicated that endurance and briskness were directly connected to changes in positivity ratio, whilst the effect of perseveration on positivity ratio was indirect via changes in negative appraisal, emotion- and problem-focused coping. The results confirm the stressful nature of the initiation of insulin treatment, and the assumptions of Lazarus’ model of stress and regulative role of temperament.

Types of prayer and depressive symptoms among cancer patients: the mediating role of rumination and social support.

Science.gov (United States)

Pérez, John E; Rex Smith, Amy; Norris, Rebecca L; Canenguez, Katia M; Tracey, Elizabeth F; Decristofaro, Susan B

2011-12-01

We examined the association between different types of prayer and depressive symptoms--with rumination and social support as potential mediators--in a sample of predominantly White, Christian, and female ambulatory cancer patients. In a cross-sectional design, 179 adult cancer outpatients completed measures of prayer, rumination, social support, depressive symptoms, and demographic variables. Type and stage of cancer were collected from electronic medical charts. Depressive symptoms were negatively correlated with adoration prayer (r = -.15), reception prayer (r = -.17), thanksgiving prayer (r = -.29), and prayer for the well-being of others (r = -.26). In the path analysis, rumination fully mediated the link between thanksgiving prayer and depressive symptoms (β for indirect effect = -.05), whereas social support partially mediated the link between prayer for others and depressive symptoms (β for indirect effect = -.05). These findings suggest that unique mechanisms may link different prayer types to lower depressive symptoms among cancer patients.

The effects of competition and implicit power motive on men's testosterone, emotion recognition, and aggression.

Science.gov (United States)

Vongas, John G; Al Hajj, Raghid

2017-06-01

A contribution to a special issue on Hormones and Human Competition. We investigated the effects of competition on men's testosterone levels and assessed whether androgen reactivity was associated with subsequent emotion recognition and reactive and proactive aggression. We also explored whether personalized power (p Power) moderated these relationships. In Study 1, 84 males competed on a number tracing task and interpreted emotions from facial expressions. In Study 2, 72 males competed on the same task and were assessed on proactive and reactive aggression. In both studies, contrary to the biosocial model of status (Mazur, 1985), winners' testosterone levels decreased significantly while losers' levels increased, albeit not significantly. Personalized power moderated the effect of competition outcome on testosterone change in both studies. Using the aggregate sample, we found that the effect of decreased testosterone levels among winners (compared to losers) was significant for individuals low in p Power but not for those with medium or high p Power. Testosterone change was positively related to emotion recognition, but unrelated to either aggression subtype. The testosterone-mediated relationship between winning and losing and emotion recognition was moderated by p Power. In addition, p Power moderated the direct (i.e., non-testosterone mediated) path between competition outcome and emotion recognition and both types of aggression: high p-Power winners were more accurate at deciphering others' emotions than high p-Power losers. Finally, among high p-Power men, winners aggressed more proactively than losers, whereas losers aggressed more reactively than winners. Collectively, these studies highlight the importance of implicit power motivation in modulating hormonal, cognitive, and behavioral outcomes arising from human competition. Copyright © 2017 Elsevier Inc. All rights reserved.

The relationship between physical and mental health: A mediation analysis.

Science.gov (United States)

Ohrnberger, Julius; Fichera, Eleonora; Sutton, Matt

2017-12-01

There is a strong link between mental health and physical health, but little is known about the pathways from one to the other. We analyse the direct and indirect effects of past mental health on present physical health and past physical health on present mental health using lifestyle choices and social capital in a mediation framework. We use data on 10,693 individuals aged 50 years and over from six waves (2002-2012) of the English Longitudinal Study of Ageing. Mental health is measured by the Centre for Epidemiological Studies Depression Scale (CES) and physical health by the Activities of Daily Living (ADL). We find significant direct and indirect effects for both forms of health, with indirect effects explaining 10% of the effect of past mental health on physical health and 8% of the effect of past physical health on mental health. Physical activity is the largest contributor to the indirect effects. There are stronger indirect effects for males in mental health (9.9%) and for older age groups in mental health (13.6%) and in physical health (12.6%). Health policies aiming at changing physical and mental health need to consider not only the direct cross-effects but also the indirect cross-effects between mental health and physical health. Copyright © 2017. Published by Elsevier Ltd.

Negative Opinion of Company Environment Mediates Career Choice of Accountancy Students

Science.gov (United States)

Tong, David Yoon Kin; Tong, Xue Fa

2012-01-01

Purpose: The purpose of this paper is to explore accountancy students' pre-employment decisions as regards pursuing a career after completing an internship. The paper aims to analyse the mediating effect of aspects of students' training experience in firms as direct/indirect factors which influence their career decisions.…

CCND1–CDK4–mediated cell cycle progression provides a competitive advantage for human hematopoietic stem cells in vivo

Science.gov (United States)

Mende, Nicole; Kuchen, Erika E.; Lesche, Mathias; Grinenko, Tatyana; Kokkaliaris, Konstantinos D.; Hanenberg, Helmut; Lindemann, Dirk; Dahl, Andreas; Platz, Alexander; Höfer, Thomas; Calegari, Federico

2015-01-01

Maintenance of stem cell properties is associated with reduced proliferation. However, in mouse hematopoietic stem cells (HSCs), loss of quiescence results in a wide range of phenotypes, ranging from functional failure to extensive self-renewal. It remains unknown whether the function of human HSCs is controlled by the kinetics of cell cycle progression. Using human HSCs and human progenitor cells (HSPCs), we report here that elevated levels of CCND1–CDK4 complexes promoted the transit from G0 to G1 and shortened the G1 cell cycle phase, resulting in protection from differentiation-inducing signals in vitro and increasing human leukocyte engraftment in vivo. Further, CCND1–CDK4 overexpression conferred a competitive advantage without impacting HSPC numbers. In contrast, accelerated cell cycle progression mediated by elevated levels of CCNE1–CDK2 led to the loss of functional HSPCs in vivo. Collectively, these data suggest that the transition kinetics through the early cell cycle phases are key regulators of human HSPC function and important for lifelong hematopoiesis. PMID:26150472

Ballistic fractures: indirect fracture to bone.

Science.gov (United States)

Dougherty, Paul J; Sherman, Don; Dau, Nathan; Bir, Cynthia

2011-11-01

Two mechanisms of injury, the temporary cavity and the sonic wave, have been proposed to produce indirect fractures as a projectile passes nearby in tissue. The purpose of this study is to evaluate the temporal relationship of pressure waves using strain gauge technology and high-speed video to elucidate whether the sonic wave, the temporary cavity, or both are responsible for the formation of indirect fractures. Twenty-eight fresh frozen cadaveric diaphyseal tibia (2) and femurs (26) were implanted into ordnance gelatin blocks. Shots were fired using 9- and 5.56-mm bullets traversing through the gelatin only, passing close to the edge of the bone, but not touching, to produce an indirect fracture. High-speed video of the impact event was collected at 20,000 frames/s. Acquisition of the strain data were synchronized with the video at 20,000 Hz. The exact time of fracture was determined by analyzing and comparing the strain gauge output and video. Twenty-eight shots were fired, 2 with 9-mm bullets and 26 with 5.56-mm bullets. Eight indirect fractures that occurred were of a simple (oblique or wedge) pattern. Comparison of the average distance of the projectile from the bone was 9.68 mm (range, 3-20 mm) for fractured specimens and 15.15 mm (range, 7-28 mm) for nonfractured specimens (Student's t test, p = 0.036). In this study, indirect fractures were produced after passage of the projectile. Thus, the temporary cavity, not the sonic wave, was responsible for the indirect fractures.

Indirect effects in dual radiation action

International Nuclear Information System (INIS)

Zaider, M.; Rossi, H.H.

1988-01-01

The basic aim in this paper is to establish the link between indirect effects of radiation action and the spatial distribution of radicals at the time of energy deposition as well as throughout subsequent diffusion and interaction. The fact that radicals diffuse for a finite distance before damaging a biomolecule has dramatic effects on their subsequent probability to result in lesions. Thus at very low DMSO concentrations, where p = 0.5, one expects - all other things being equal - some 75% of the lesions to result from indirect or semidirect lesions. The number calculated here is lower (15%), a direct result of the fact that such lesions involve proximity functions modulated by diffusion. At higher DMSO concentrations this percentage becomes progressively smaller, as expected. It appears thus that for low-LET radiation, the relative amount of indirect damage in single tracks (also termed intratrack or single events) action is very small. By contrast, intertrack (or two-event) contributions will have the ratio between direct and (indirect + semidirect) contributions given by p 2 /(1-p 2 ). The reason for this is that sublesions from different tracks are uniformly distributed throughout the cell nucleus; their probability of interaction should not depend on any previous diffusional processes. For the example given above (p = 0.5) they do expect 65% of intertrack (two-hit) lesions to have resulted from indirect or semidirect mechanisms. This contrast between the almost exclusively direct character of intratrack lesions and the dominant role of indirect action in intertrack lesions produced by low-LET radiation is an important conclusion of this study

Socio-hydrologic Modeling to Understand and Mediate the Competition for Water between Humans and Ecosystems: Murrumbidgee River Basin, Australia

Science.gov (United States)

van Emmerik, Tim; Sivapalan, Murugesu; Li, Zheng; Pande, Saket; Savenije, Hubert

2014-05-01

Around the world the demand for water resources is growing in order to satisfy rapidly increasing human populations, leading to competition for water between humans and ecosystems. An entirely new and comprehensive quantitative framework is needed to establish a holistic understanding of that competition, thereby enabling development and evaluation of effective mediation strategies. We present a case study centered on the Murrumbidgee river basin in eastern Australia that illustrates the dynamics of the balance between water extraction and use for food production and efforts to mitigate and reverse consequent degradation of the riparian environment. Interactions between patterns of water resources management and climate driven hydrological variability within the prevailing socio-economic environment have contributed to the emergence of new whole system dynamics over the last 100 years. In particular, data analysis reveals a pendulum swing between an exclusive focus on agricultural development and food production in the initial stages of water resources development and its attendant socio-economic benefits, followed by the gradual realization of the adverse environmental impacts, efforts to mitigate these with the use of remedial measures, and ultimately concerted efforts and externally imposed solutions to restore environmental health and ecosystem services. A quasi-distributed coupled socio-hydrologic system model that explicitly includes the two-way coupling between human and hydrological systems, including evolution of human values/norms relating to water and the environment, is able to mimic broad features of this pendulum swing. The model consists of coupled nonlinear differential equations that include four state variables describing the co-evolution of storage capacity, irrigated area, human population, and ecosystem health, which are all connected by feedback mechanisms. The model is used to generate insights into the dominant controls of the trajectory of

Authoritative Parenting and Cigarette Smoking Among Multiethnic Preadolescents: The Mediating Role of Anti-Tobacco Parenting Strategies

Science.gov (United States)

Highland, Krista B.; Tercyak, Kenneth P.; Luta, Gheorghe; Niaura, Raymond S.

2014-01-01

Introduction Parenting has been shown to affect smoking among children in U.S. majority groups, but less is known about this association among multiethnic urban populations. Our study examines the role of parenting on smoking among a highly diverse sample. Methods Health surveys were collected from eighth graders (N =459) in 2 low-income urban schools. Structural equation models examined the direct and indirect effects of authoritative parenting on lifetime smoking. A moderated mediation analysis examined whether indirect effects of authoritative parenting vary among racial/ethnic groups. Results Authoritative controlling parenting, characterized by limit setting, was positively associated with anti-tobacco parenting. Anti-tobacco parenting was inversely associated with smoking, mediating the relationship between controlling parenting and smoking. There was no evidence that mediation was moderated by race/ethnicity. Conclusions Parent training, which focuses on setting rules and expectations, can be an important and universal element of smoking prevention programs targeted to youth in diverse communities. PMID:24306966

Authoritative parenting and cigarette smoking among multiethnic preadolescents: the mediating role of anti-tobacco parenting strategies.

Science.gov (United States)

Stanton, Cassandra A; Highland, Krista B; Tercyak, Kenneth P; Luta, Gheorghe; Niaura, Raymond S

2014-01-01

Parenting has been shown to affect smoking among children in U.S. majority groups, but less is known about this association among multiethnic urban populations. Our study examines the role of parenting on smoking among a highly diverse sample. Health surveys were collected from eighth graders (N = 459) in 2 low-income urban schools. Structural equation models examined the direct and indirect effects of authoritative parenting on lifetime smoking. A moderated mediation analysis examined whether indirect effects of authoritative parenting vary among racial/ethnic groups. Authoritative controlling parenting, characterized by limit setting, was positively associated with anti-tobacco parenting. Anti-tobacco parenting was inversely associated with smoking, mediating the relationship between controlling parenting and smoking. There was no evidence that mediation was moderated by race/ethnicity. Parent training, which focuses on setting rules and expectations, can be an important and universal element of smoking prevention programs targeted to youth in diverse communities.

Demonstration of pollinator-mediated competition between two native Impatiens species, Impatiens noli-tangere and I. textori (Balsaminaceae)

OpenAIRE

Tokuda, Nanako; Hattori, Mitsuru; Abe, Kota; Shinohara, Yoshinori; Nagano, Yusuke; Itino, Takao

2015-01-01

Plant?plant interspecific competition via pollinators occurs when the flowering seasons of two or more plant species overlap and the pollinator fauna is shared. Negative sexual interactions between species (reproductive interference) through improper heterospecific pollen transfer have recently been reported between native and invasive species demonstrating pollination-driven competition. We focused on two native Impatiens species (I.?noli-tangere and I.?textori) found in Japan and examined w...

The finite sample performance of estimators for mediation analysis under sequential conditional independence

DEFF Research Database (Denmark)

Huber, Martin; Lechner, Michael; Mellace, Giovanni

Using a comprehensive simulation study based on empirical data, this paper investigates the finite sample properties of different classes of parametric and semi-parametric estimators of (natural) direct and indirect causal effects used in mediation analysis under sequential conditional independence...

The Influence of Computer-Mediated Communication Systems on Community

Science.gov (United States)

Rockinson-Szapkiw, Amanda J.

2012-01-01

As higher education institutions enter the intense competition of the rapidly growing global marketplace of online education, the leaders within these institutions are challenged to identify factors critical for developing and for maintaining effective online courses. Computer-mediated communication (CMC) systems are considered critical to…

Synchronization of indirectly coupled Lorenz oscillators

Indian Academy of Sciences (India)

Synchronization of indirectly coupled Lorenz oscillators: An experimental study. Amit Sharma Manish Dev Shrimali. Synchronization, Coupled Systems and Networks Volume 77 Issue 5 November 2011 pp 881-889 ... The in-phase and anti-phase synchronization of indirectly coupled chaotic oscillators reported in Phys. Rev ...

Indirect estimators in US federal programs

CERN Document Server

1996-01-01

In 1991, a subcommittee of the Federal Committee on Statistical Methodology met to document the use of indirect estimators - that is, estimators which use data drawn from a domain or time different from the domain or time for which an estimate is required. This volume comprises the eight reports which describe the use of indirect estimators and they are based on case studies from a variety of federal programs. As a result, many researchers will find this book provides a valuable survey of how indirect estimators are used in practice and which addresses some of the pitfalls of these methods.

Culture of innovation and business competitiveness in knowledge intensive services.The mediating role of co-creative culture; Cultura innovadora y competitividad en las empresas de servicios intensivos en conocimiento. El papel mediador de la cultura co-creadora

Energy Technology Data Exchange (ETDEWEB)

Santos Vijande, M. L.; Gonzalez Mieres, C.; Lopez Sanchez, J. A.

2012-07-01

This research investigates the relationship between innovative culture and performance among knowledge-intensive business services (KIBS). Performance indicators include customer-related outcomes and market and financial results relative to competition. To provide insight into how inattentiveness contributes to sustaining a KIBS' competitiveness, the mediating role of the predisposition to involve customers and front-line employees in new service development is also considered. In accordance with the objectives of the research, and from an extensive review of the literature, the conceptual model proposed is tested on a sample of 154 Spanish KIBS using structural equation modelling. Results show that KIBS appraisal of customers and front-line employees participation in new service co-creation is strongly determined by the firm's innovative culture. (Author)

Competitive Intelligence.

Science.gov (United States)

Bergeron, Pierrette; Hiller, Christine A.

2002-01-01

Reviews the evolution of competitive intelligence since 1994, including terminology and definitions and analytical techniques. Addresses the issue of ethics; explores how information technology supports the competitive intelligence process; and discusses education and training opportunities for competitive intelligence, including core competencies…

TOXOCARIASIS: SEROLOGICAL DIAGNOSIS BY INDIRECT ANTIBODY COMPETITION ELISA Diagnóstico sorológico da toxocaríase através do método de ELISA indireto de competição

Directory of Open Access Journals (Sweden)

Cáris Maroni NUNES

1999-03-01

Full Text Available Toxocariasis is caused by infection of man by Toxocara canis and Toxocara cati larvae, the common roundworm of dogs and cats. Because larvae are difficult to detect in tissues, diagnosis is mostly based on serology. Non specific reactions are observed mainly due to cross-reactivity with Ascaris sp antigens. This investigation aimed at developing and evaluating an indirect antibody competition ELISA (IACE employing a specific rabbit IgG anti-Toxocara canis excretory-secretory antigens as the competition antibody, in order to improve indirect ELISA specificity performed for toxocariasis diagnosis. For that, the rabbit IgG was previously absorbed by Ascaris suum adult antigens. Sensitivity and specificity of IACE were first evaluated in 28 serum samples of mice experimentally infected with T. canis embryonated eggs. Adopting cut-off value established in this population before infection, sensitivity and specificity were 100% after 20 days post-inoculation. For human population IACE was evaluated using sera from 440 patients with clinical signs of toxocariasis and the cut-off value was established with 60 serum samples from apparently healthy individuals. Using as reference test the indirect ELISA performed by Adolfo Lutz Institute, sensitivity was 60.2%, specificity was 98% and concordance was 77.3%. Repeatability of IACE was evaluated by the inter-reactions variation coefficient (2.4%.A toxocaríase, uma emergente zoonose, é uma síndrome clínica decorrente da infecção humana por larvas de Toxocara canis e Toxocara cati, parasitas intestinais de cães e gatos, respectivamente. A dificuldade de detecção das larvas nos tecidos e a inespecificidade dos sinais clínicos tornam os testes sorológicos os meios diagnósticos mais adequados. Os antígenos excretores-secretores de T. canis empregados nos testes sorológicos, embora tenham contribuído para melhorar a especificidade destes, apresentam reações cruzadas com diversos parasitas

Healthy Competition and Unsound Comparison: Reforming Educational Competition in Singapore

Science.gov (United States)

Christensen, Søren

2015-01-01

It is frequently claimed that the "competition state" responds to external competition by making competition increasingly central to its internal processes as well. This article discusses education reform in Singapore as departing from the opposite position. In Singapore "excessive" competition in education is now targeted by…

THE INDIRECT OBJECT (IO) – ALBANIAN AND ENGLISH

OpenAIRE

Shkelqim Millaku; Xhevahire Topanica

2016-01-01

The aim of this study is too corporate the function of the indirect object between Albanian and English language. The function and the Albanian typical case for indirect object are dative and ablative. This grammatical phenomena is the full contrast between two languages because in English language doesn’t exist dative and ablative us in Albanian. In Albanian and English language, the indirect object is more heterogenic than the direct object. The indirect (direct) object in both of languages...

Reinjury anxiety, coping, and return-to-sport outcomes: a multiple mediation analysis.

Science.gov (United States)

Wadey, Ross; Podlog, Leslie; Hall, Morgan; Hamson-Utley, Jordan; Hicks-Little, Charlie; Hammer, Chris

2014-08-01

This study aimed to examine whether the dimensions of reinjury anxiety (i.e., intensity, frequency, and direction) predicted perceived return-to-sport outcomes and whether coping mediated this relationship. Using a cross-sectional research design, 335 participants (M age = 23.5; SD = 6.6) who had sustained a sports-related injury preventing participation in training and competition for a minimum of 4 weeks (M time loss = 98 days; SD = 96.8) completed measures of reinjury anxiety (RIA-RE subscale of the Reinjury Anxiety Inventory (RIAI); Walker, Thatcher, & Lavallee, 2010), coping (MCOPE; Crocker & Graham, 1995), and perceived return-to-sport outcomes (RSSIQ; Podlog & Eklund, 2005). Pearson product-moment correlation and Preacher and Hayes's (2008) bootstrapping procedure were used to analyze the data. Consistent with our hypotheses, results indicated a positive relationship between reinjury anxiety (intensity and frequency) and heightened return concerns, whereas reinjury anxiety interpreted as facilitative toward postinjury performance was associated with a positive renewed perspective on sport participation. Significant indirect effects for coping were found for wishful thinking, venting of emotions, denial, and behavioral disengagement. Future avenues of research that aim to provide a greater knowledge and understanding of the relationship between reinjury anxiety and return-to-sport outcomes are discussed, including the need for alternative theoretical perspectives and diverse methodologies.

Beyond compliance using environmental, health and safety management information systems (EMISs) to provide quantified competitive advantages

Energy Technology Data Exchange (ETDEWEB)

Schroeder, J.V.; Mayer, G.

1999-07-01

In the last 20 years, federal, state and local regulations have provided regulatory incentives for industry to better manage environmental, health and safety (EHS) practices. In order for voluntary EHS management practices to move beyond compliance and continue improving, specific, quantifiable benefits must result. That is, companies must achieve some competitive advantage from implementing EHS improvements that are considered voluntary. Recently, many private companies and public agencies have been giving significant consideration toward the implementation of an EHS management information system (EMIS). Currently considered voluntary, the automation of EHS data collection, storage, retrieval and reporting is subject to the same benefit expectations that other EHS improvements are subject to. The benefits resulting from an EMIS typically result from a reduction in either direct or indirect costs. Direct costs, consisting primarily of labor hours, permit fees, disposal costs, etc., are definable and easily to quantify. Indirect costs, which are comprised of reduced risks and liabilities, are less easily quantifiable. In fact, many have abandoned hope of ever quantifying expected benefits from indirect costs, and simply lump all indirect benefits into a qualitative, catch-all category called intangible benefits. However, by statistically analyzing individual risk events over an expected project life, anticipated benefits can be objectively and accurately quantified. Through the use of a case study, this paper will describe the process of quantifying direct and indirect benefits resulting from the implementation of an EMIS. The paper will describe the application of a statistical model to estimate indirect benefits and will demonstrate how the results of the benefit quantification can be used to make sound, business based decisions based on a required rate of return/return on investment.

A taste of dark matter. Flavour constraints on pseudoscalar mediators

International Nuclear Information System (INIS)

Dolan, Matthew J.; McCabe, Christopher

2014-12-01

Dark matter interacting via the exchange of a light pseudoscalar can induce observable signals in indirect detection experiments and experience large self-interactions while evading the strong bounds from direct dark matter searches. The pseudoscalar mediator will however induce flavour-changing interactions in the Standard Model, providing a promising alternative way to test these models. We investigate in detail the constraints arising from rare meson decays and fixed target experiments for different coupling structures between the pseudoscalar and Standard Model fermions. The resulting bounds are highly complementary to the information inferred from the dark matter relic density and the constraints from primordial nucleosynthesis. We discuss the implications of our findings for the dark matter self-interaction cross section and the prospects of probing dark matter coupled to a light pseudoscalar with direct or indirect detection experiments. In particular, we find that a pseudoscalar mediator can only explain the Galactic Centre excess if its mass is above that of the B mesons, and that it is impossible to obtain a sufficiently large direct detection cross section to account for the DAMA modulation.

Indirect reciprocity with optional interactions.

Science.gov (United States)

Ghang, Whan; Nowak, Martin A

2015-01-21

Indirect reciprocity is a mechanism for the evolution of cooperation that is relevant for prosocial behavior among humans. Indirect reciprocity means that my behavior towards you also depends on what you have done to others. Indirect reciprocity is associated with the evolution of social intelligence and human language. Most approaches to indirect reciprocity assume obligatory interactions, but here we explore optional interactions. In any one round a game between two players is offered. A cooperator accepts a game unless the reputation of the other player indicates a defector. For a game to take place, both players must accept. In a game between a cooperator and a defector, the reputation of the defector is revealed to all players with probability Q. After a sufficiently large number of rounds the identity of all defectors is known and cooperators are no longer exploited. The crucial condition for evolution of cooperation can be written as hQB>1, where h is the average number of rounds per person and B=(b/c)-1 specifies the benefit-to-cost ratio. We analyze both stochastic and deterministic evolutionary game dynamics. We study two extensions that deal with uncertainty: hesitation and malicious gossip. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biotin-Streptavidin Competition Mediates Sensitive Detection of Biomolecules in Enzyme Linked Immunosorbent Assay.

Science.gov (United States)

Lakshmipriya, Thangavel; Gopinath, Subash C B; Tang, Thean-Hock

2016-01-01

Enzyme Linked Immunosorbent Assay (ELISA) is the gold standard assay for detecting and identifying biomolecules using antibodies as the probe. Improving ELISA is crucial for detecting disease-causing agents and facilitating diagnosis at the early stages of disease. Biotinylated antibody and streptavidin-conjugated horse radish peroxide (streptavidin-HRP) often are used with ELISA to enhance the detection of various kinds of targets. In the present study, we used a competition-based strategy in which we pre-mixed free biotin with streptavidin-HRP to generate high-performance system, as free biotin occupies some of the biotin binding sites on streptavidin, thereby providing more chances for streptavidin-HRP to bind with biotinylated antibody. ESAT-6, which is a protein secreted early during tuberculosis infection, was used as the model target. We found that 8 fM of free biotin mixed with streptavidin-HRP anchored the higher detection level of ESAT-6 by four-fold compared with detection without free biotin (only streptavidin-HRP), and the limit of detection of the new method was 250 pM. These results suggest that biotin-streptavidin competition can be used to improve the diagnosis of analytes in other types of sensors.

Emotional Intelligence and Creativity: The Mediating Role of Generosity and Vigor

Science.gov (United States)

Carmeli, Abraham; McKay, Alexander S.; Kaufman, James C.

2014-01-01

This study examines whether and why emotional intelligence may result in enhanced creativity in the workplace. Using a time-lagged data set collected from employees in three firms, we examined a mediation model where emotional intelligence is indirectly related to creativity serially, through generosity and vigor. The results of structural…

EDITORIAL: Physics competitions Physics competitions

Science.gov (United States)

Jordens, H.; Mathelitsch, L.

2010-07-01

This editorial opens the second special section on physics competitions in European Journal of Physics. In the first section last year, we asked for feedback on the idea of such a section and on the content of the articles. We received no answer whatsoever, which can be interpreted in two ways: the section is not interesting enough to raise motivation for feedback, or the reader is satisfied. Having no indication which scenario is the correct one, we are optimistic and favour the second. The section at hand contains three articles. Again, as last year, the organizer of the annual Olympiad reports on tasks and outcomes of this competition. The Olympiad took place in Merida, Mexico, and was by far the largest event with 316 contestants from 68 countries. Again, the predominance of Asian/Chinese students was manifest, showing how serious the training is taken by both their authorities and students. Unfortunately, the winners of the last International Young Physicists' Tournament (IYPT), the team from Korea, did not accept the offer to report on their prize-winning contribution. We are thankful that two students from Austria, who achieved second place with their team, took over and reported on the task which they presented in the finals of the competition. It connects the fields of sport and physics and explains a special move in skateboarding. The third contribution introduces a different competition, 'International Conference of Young Scientists'. On one hand, as in the Olympiad, it addresses individuals, not teams. On the other, as in the IYPT, students have several months to prepare and also the quality of the presentation is an important element of the judgment. In fact, this competition comes closer to real scientific research compared to the other events. Finally and again, we hope that this section will serve several purposes: To show the competitions as a very important tool in the support of gifted students. To raise awareness amongst university teachers, and

Power market competition

International Nuclear Information System (INIS)

Kelly, J.

1998-01-01

In the Unites States the prospect of greater competition in wholesale power market was immediately eclipsed by talk of retail competition. Attempts to move to retail competition have been costly and complex. Prudent public policy and economic analyses suggest that retail competition not be implemented until it can first be demonstrated that effective competition exists in wholesale power markets [it

Lunabotics Mining Competition

Science.gov (United States)

Mueller, Rob; Murphy, Gloria

2010-01-01

This slide presentation describes a competition to design a lunar robot (lunabot) that can be controlled either remotely or autonomously, isolated from the operator, and is designed to mine a lunar aggregate simulant. The competition is part of a systems engineering curriculum. The 2010 competition winners in five areas of the competition were acknowledged, and the 2011 competition was announced.

Indirect Medical Education and Disproportionate Share Adj...

Data.gov (United States)

U.S. Department of Health & Human Services — Indirect Medical Education and Disproportionate Share Adjustments to Medicare Inpatient Payment Rates The indirect medical education (IME) and disproportionate share...

Sperm competition, but not major histocompatibility divergence, drives differential fertilization success between alternative reproductive tactics in Chinook salmon.

Science.gov (United States)

Lehnert, S J; Helou, L; Pitcher, T E; Heath, J W; Heath, D D

2018-01-01

Post-copulatory sexual selection processes, including sperm competition and cryptic female choice (CFC), can operate based on major histocompatibility (MH) genes. We investigated sperm competition between male alternative reproductive tactics [jack (sneaker) and hooknose (guard)] of Chinook salmon (Oncorhynchus tshawytscha). Using a full factorial design, we examined in vitro competitive fertilization success of paired jack and hooknose males at three time points after sperm activation (0, 15 and 60 s) to test for male competition, CFC and time effects on male fertilization success. We also examined egg-mediated CFC at two MH genes by examining both the relationship between competitive fertilization success and MH divergence as well as inheritance patterns of MH alleles in resulting offspring. We found that jacks sired more offspring than hooknose males at 0 s post-activation; however, jack fertilization success declined over time post-activation, suggesting a trade-off between sperm speed and longevity. Enhanced fertilization success of jacks (presumably via higher sperm quality) may serve to increase sneaker tactic competitiveness relative to dominant hooknose males. We also found evidence of egg-mediated CFC (i.e. female × male interaction) influencing competitive fertilization success; however, CFC was not acting on the MH genes as we found no relationship between fertilization success and MH II β 1 or MH I α 1 divergence and we found no deviations from Mendelian inheritance of MH alleles in the offspring. Our study provides insight into evolutionary mechanisms influencing variation in male mating success within alternative reproductive tactics, thus underscoring different strategies that males can adopt to attain success. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

Indirect Comorbidity in Childhood and Adolescence

Directory of Open Access Journals (Sweden)

William eCopeland

2013-11-01

Full Text Available Objective: Comorbidity between psychiatric disorders is common, but pairwise associations between two disorders may be explained by the presence of other diagnoses that are associated with both disorders or indirect comorbidity. Method: Comorbidities of common childhood psychiatric disorders were tested in three community samples of children ages 6 to 17 (8931 observations of 2965 subjects. Psychiatric disorder status in all three samples was assessed with the Child and Adolescent Psychiatric Assessment. Indirect comorbidity was defined as A-B associations that decreased from significance to nonsignificance after adjusting for other disorders. Results: All tested childhood psychiatric disorders were positively associated in bivariate analyses. After adjusting for comorbidities, many ssociations involving a behavioral disorder and an emotional disorder were attenuated suggesting indirect comorbidity. Generalized anxiety and depressive disorders displayed a very high level of overlap (adjusted OR=37.9. All analyses were rerun with depressive disorders grouped with generalized anxiety disorder in a single distress disorders category. In these revised models, all associations between and emotional disorder and a behavior disorder met our criteria for indirect comorbidity except for the association of oppositional defiant disorder with distress disorders (OR=11.3. Follow-up analyses suggested that the indirect associations were primarily accounted for by oppositional defiant disorder and the distress disorder category. There was little evidence of either sex differences or differences by developmental period Conclusions: After accounting for the overlap between depressive disorders with generalized anxiety disorder, direct comorbidity between emotional and behavioral disorders was uncommon. When there was evidence of indirect comorbidity, ODD and distress disorders were the key intermediary diagnoses accounting for the apparent associations.

Peer Relationships and Internalizing Problems in Adolescents: Mediating Role of Self-Esteem

Science.gov (United States)

Bosacki, Sandra; Dane, Andrew; Marini, Zopito

2007-01-01

This study examined whether self-esteem mediated the association between peer relationships and internalizing problems (i.e., depression and social anxiety). A total of 7290 (3756 girls) adolescents (ages 13-18 years) completed self-report measures of peer relationships, including direct and indirect victimization, social isolation, friendship…

The Relationship between SES and Reading Comprehension in Chinese: A Mediation Model

Directory of Open Access Journals (Sweden)

Yahua Cheng

2017-04-01

Full Text Available An increasing body of research provides evidence that socioeconomic status (SES was significantly related to children’s reading development; however, the psychological mechanism underlying the association between them remained an open question. The present study is designed to test the hypothesized three-path effect of vocabulary knowledge and morphological awareness as mediators between SES and sentence reading comprehension in Chinese first-graders. Results of mediation model showed that SES exerted its effect on sentence reading comprehension through the indirect path via the simple mediating effect of morphological awareness and the three-path mediating effect of vocabulary knowledge and morphological awareness. The findings highlight a previously unidentified mechanism of the relationship between SES and reading comprehension in Chinese young children.

Self-Stigma Mediates the Impact of Insight on Current Suicide Ideation in Suicide Attempters with Schizophrenia: Results of a Moderated Mediation Approach.

Science.gov (United States)

Lien, Yin-Ju; Chang, Hsin-An; Kao, Yu-Chen; Tzeng, Nian-Sheng; Yeh, Chin-Bin; Loh, Ching-Hui

2017-09-04

This study examined the relationships among insight, self-stigma, self-esteem, hope, quality of life, and suicidal behavior in individuals diagnosed as having schizophrenia. Hypotheses concerning mediating and moderating effects were examined. A total of 170 community-dwelling patients with schizophrenia participated in the study. The results revealed a negative association between insight and suicide ideation, which was partially mediated by self-stigma. Moreover, this indirect link was stronger among patients with suicide attempts than among those without attempts. We discuss the implications of these results for preventing or reducing the considerable risks of suicide in this population. © 2017 The American Association of Suicidology.

The relationship among image, satisfaction and loyalty – innovative factor of competitiveness for shopping centers

Directory of Open Access Journals (Sweden)

Ioana-Nicoleta Abrudan

2015-05-01

Full Text Available Currently, most markets are characterized by high competition among shopping centers. Under these circumstances, the evolution in the competitiveness and performance of the centers is increasingly linked to the success in the innovation of current activities, which is aimed at improving their image and increasing customer satisfaction and loyalty. The purpose of the present research is to study the influence of innovation activities through the image components on behavioural loyalty, mediated by satisfaction (affective loyalty and conative loyalty. The authors aim to investigate, using a questionnaire survey among the customers of Cluj-Napoca shopping centers, the relationship among the components of image and satisfaction and the various types of loyalty. The conclusions of the structural equations modelling reveal that most components of the image (assortment, price, loyalty policy, décor, service and communication directly and positively influence satisfaction, and that satisfaction and conative loyalty mediate the relationship between image and behavioural loyalty. The results reveal important managerial implications from the point of view of innovative actions of shopping centers, which can contribute to attracting and keeping customers, these contributing not only to creating loyal patrons, but also to increasing their competitiveness and to achieving better positioning.

Trust, Knowledge Creation and Mediating Effects of Knowledge Transfer Processes

Directory of Open Access Journals (Sweden)

Anna Sankowska

2016-01-01

Full Text Available This paper investigates how organizational trust contributes to knowledge transfer processes and knowledge creation both directly and indirectly. The mediation analyses were used. The findings using cross-sectional data from Polish companies suggest a new way of thinking in respect of how crucial is trust to creation of knowledge unconnected to organizational memory.

Forecasting of indirect consumables for a Job Shop

Science.gov (United States)

Shakeel, M.; Khan, S.; Khan, W. A.

2016-08-01

A job shop has an arrangement where similar machines (Direct consumables) are grouped together and use indirect consumables to produce a product. The indirect consumables include hack saw blades, emery paper, painting brush etc. The job shop is serving various orders at a particular time for the optimal operation of job shop. Forecasting is required to predict the demand of direct and indirect consumables in a job shop. Forecasting is also needed to manage lead time, optimize inventory cost and stock outs. The objective of this research is to obtain the forecast for indirect consumables. The paper shows how job shop can manage their indirect consumables more accurately by establishing a new technique of forecasting. This results in profitable use of job shop by multiple users.

[The mediating role of organizational citizenship behavior between organizational justice and organizational effectiveness in nursing organizations].

Science.gov (United States)

Park, Wall Yun; Yoon, Sook Hee

2009-04-01

This study was a secondary analysis to verify the mediating role of organizational citizenship behavior (OCB) between organizational justice (OJ) and organizational effectiveness (OE) in nursing organizations. The RN-BSNs and their colleagues in Seoul and Busan were subjects. The data was collected for 20 days between September 13 and October 2, 2004. Two hundred eighty three data sets were used for the final analysis. The fitness of models were tested using AMOS 5. The fitness of hypothetical model was moderate. Procedural Justice (PJ), Interaction Justice (IJ) and Distributive Justice (DJ) had direct effects on Job Satisfaction (JS), Organizational Commitment (OC) and Turnover Intention (TI) in OE, and indirect effects on JS, OC and TI mediated by OCB. The modified model improved with ideal fitness showed the causal relations among OE. In modified model, PJ, IJ and DJ had direct positive effects on OCB and JS and OC in OE, and indirect effects on JS and OC mediated by OCB. JS and OC in OE had a direct negative effect on TI. OCB mediated the relationship between OJ and OE, so the nursing managers should enhance OCB of the nurses in order to improve OE.

Interaction of nitroaromatic radiosensitizers with irradiated polyadenylic acid as measured by an indirect immunochemical assay with specificity for the 8,5'-cycloadenosine moiety

Energy Technology Data Exchange (ETDEWEB)

Fuciarelli, A F; Mele, F G; Raleigh, J A

1987-04-01

The relative reactivity of a series of nitroaromatic radiosensitizers toward the C(5') radical intermediate leading to 8,5'-cycloadenosine formation in deoxygenated solutions of irradiated polyadenylic acid (poly A) was assessed using standard competition kinetic analysis. Formation of 8,5'-cycloadenosine was assayed by an indirect, competitive, enzyme-linked immunosorbent assay (ELISA) described in an earlier report. In the absence of oxygen, the nitroaromatics inhibit 8,5'-cyclonucleoside formation in a way which generally increases with radiosensitizer electron affinity. Although hydroxyl radical scavenging by the nitroaromatics may account for a relatively small decrease in 8,5'cyclonucleoside formation, the data suggest that oxidation of the C(5') radical intermediate is the more plausible explanation for the decreased yield of the 8,5'-cyclonucleoside with increasing nitroaromatic electron affinity.