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Sample records for competition linking form

  1. Sperm competition: linking form to function

    PubMed Central

    2008-01-01

    Background Using information from physics, biomechanics and evolutionary biology, we explore the implications of physical constraints on sperm performance, and review empirical evidence for links between sperm length and sperm competition (where two or more males compete to fertilise a female's eggs). A common theme in the literature on sperm competition is that selection for increased sperm performance in polyandrous species will favour the evolution of longer, and therefore faster swimming, sperm. This argument is based on the common assumption that sperm swimming velocity is directly related to sperm length, due to the increased thrust produced by longer flagella. Results We critically evaluate the evidence for links between sperm morphology and swimming speed, and draw on cross-disciplinary studies to show that the assumption that velocity is directly related to sperm length will rarely be satisfied in the microscopic world in which sperm operate. Conclusion We show that increased sperm length is unlikely to be driven by selection for increased swimming speed, and that the relative lengths of a sperm's constituent parts, rather than their absolute lengths, are likely to be the target of selection. All else being equal, we suggest that a simple measure of the ratio of head to tail length should be used to assess the possible link between morphology and speed. However, this is most likely to be the case for external fertilizers in which females have relatively limited opportunity to influence a sperm's motility. PMID:19032741

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

    PubMed

    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.

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

    PubMed

    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. PMID:23595418

  4. Demolishing the Competition: The Longitudinal Link between Competitive Video Games, Competitive Gambling, and Aggression

    ERIC Educational Resources Information Center

    Adachi, Paul J. C.; Willoughby, Teena

    2013-01-01

    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…

  5. Competitiveness mediates the link between personality and group performance.

    PubMed

    Graziano, W G; Hair, E C; Finch, J F

    1997-12-01

    The performance of individuals within groups, and of groups as units, is the product of immediate goal structures and personality differences pertinent to those goals among group members. A level-of-analysis approach linked the dimension of agreeableness to situated competitiveness and task performance in group settings. Hypotheses were (a) individual differences in self-rated and other-rated competitiveness are related (inversely) to the Big Five dimension of agreeableness, (b) immediately situated promotive and contrient goal structures influence self-ratings of competitiveness, (c) immediate goal structures differentially activate competitiveness to affect task performance in groups, and (d) agreeableness effects on task performance are partially mediated by competitiveness. Structural equation modeling corroborated hypotheses about the links among agreeableness, competitiveness, and task performance.

  6. Modelling the multidimensional niche by linking functional traits to competitive performance.

    PubMed

    Maynard, Daniel S; Leonard, Kenneth E; Drake, John M; Hall, David W; Crowther, Thomas W; Bradford, Mark A

    2015-07-22

    Linking competitive outcomes to environmental conditions is necessary for understanding species' distributions and responses to environmental change. Despite this importance, generalizable approaches for predicting competitive outcomes across abiotic gradients are lacking, driven largely by the highly complex and context-dependent nature of biotic interactions. Here, we present and empirically test a novel niche model that uses functional traits to model the niche space of organisms and predict competitive outcomes of co-occurring populations across multiple resource gradients. The model makes no assumptions about the underlying mode of competition and instead applies to those settings where relative competitive ability across environments correlates with a quantifiable performance metric. To test the model, a series of controlled microcosm experiments were conducted using genetically related strains of a widespread microbe. The model identified trait microevolution and performance differences among strains, with the predicted competitive ability of each organism mapped across a two-dimensional carbon and nitrogen resource space. Areas of coexistence and competitive dominance between strains were identified,and the predicted competitive outcomes were validated in approximately 95% of the pairings. By linking trait variation to competitive ability, our work demonstrates a generalizable approach for predicting and modelling competitive outcomes across changing environmental contexts. PMID:26136444

  7. Modelling the multidimensional niche by linking functional traits to competitive performance

    PubMed Central

    Maynard, Daniel S.; Leonard, Kenneth E.; Drake, John M.; Hall, David W.; Crowther, Thomas W.; Bradford, Mark A.

    2015-01-01

    Linking competitive outcomes to environmental conditions is necessary for understanding species' distributions and responses to environmental change. Despite this importance, generalizable approaches for predicting competitive outcomes across abiotic gradients are lacking, driven largely by the highly complex and context-dependent nature of biotic interactions. Here, we present and empirically test a novel niche model that uses functional traits to model the niche space of organisms and predict competitive outcomes of co-occurring populations across multiple resource gradients. The model makes no assumptions about the underlying mode of competition and instead applies to those settings where relative competitive ability across environments correlates with a quantifiable performance metric. To test the model, a series of controlled microcosm experiments were conducted using genetically related strains of a widespread microbe. The model identified trait microevolution and performance differences among strains, with the predicted competitive ability of each organism mapped across a two-dimensional carbon and nitrogen resource space. Areas of coexistence and competitive dominance between strains were identified, and the predicted competitive outcomes were validated in approximately 95% of the pairings. By linking trait variation to competitive ability, our work demonstrates a generalizable approach for predicting and modelling competitive outcomes across changing environmental contexts. PMID:26136444

  8. Forms of Competitive Attitude and Achievement Orientation in Relation to Disordered Eating.

    ERIC Educational Resources Information Center

    Burckle, Michelle A.; Ryckman, Richard M.; Gold, Joel A.; Thornton, Bill; Audesse, Roberta J.

    1999-01-01

    Examined the differential contributions of two forms of competitive attitude to disordered eating in 198 female Caucasian college students. Results show that it is not competition per se that is a primary contributor to eating disorders but rather a hypercompetitiveness form of competitive attitude. (SLD)

  9. Linking pseudouridine synthases to growth, development and cell competition.

    PubMed

    Tortoriello, Giuseppe; de Celis, José F; Furia, Maria

    2010-08-01

    Eukaryotic pseudouridine synthases direct RNA pseudouridylation and bind H/ACA small nucleolar RNA (snoRNAs), which, in turn, may act as precursors of microRNA-like molecules. In humans, loss of pseudouridine synthase activity causes dyskeratosis congenita (DC), a complex systemic disorder characterized by cancer susceptibility, failures in ribosome biogenesis and telomere stability, and defects in stem cell formation. Considering the significant interest in deciphering the various molecular consequences of pseudouridine synthase failure, we performed a loss of function analysis of minifly (mfl), the pseudouridine synthase gene of Drosophila, in the wing disc, an advantageous model system for studies of cell growth and differentiation. In this organ, depletion of the mfl-encoded pseudouridine synthase causes a severe reduction in size by decreasing both the number and the size of wing cells. Reduction of cell number was mainly attributable to cell death rather than reduced proliferation, establishing that apoptosis plays a key role in the development of the loss of function mutant phenotype. Depletion of Mfl also causes a proliferative disadvantage in mosaic tissues that leads to the elimination of mutant cells by cell competition. Intriguingly, mfl silencing also triggered unexpected effects on wing patterning and cell differentiation, including deviations from normal lineage boundaries, mingling of cells of different compartments, and defects in the formation of the wing margin that closely mimic the phenotype of reduced Notch activity. These results suggest that a component of the pseudouridine synthase loss of function phenotype is caused by defects in Notch signalling.

  10. Analysis of optical amplifier gain competition attack in a point-to-point WDM link

    NASA Astrophysics Data System (ADS)

    Deng, Tao; Subramaniam, Suresh

    2002-07-01

    Gain competition in an optical amplifier can result in a performance-degrading reduction in the gain of a channel if the overall input power of the amplifier is increased. A gain competition attack may be realized by one or more attackers (pretending to be legitimate users) increasing their source powers in order to degrade the quality of service seen by other users. In this paper, we study the effect of an optical amplifier gain competition attack in a point-to-point WDM link. By looking at the relative OSNR degradation ratio of the attacked channels, we show that Automatic Gain Control mechanisms can alleviate the absolute OSNR degradation to a significant extent, but cannot immunize the system from performance deterioration if the attacking user's power is strong enough. Adding more amplifiers to a link will enhance the service quality as well as the system's robustness against a gain competition attack at the price of higher network cost.

  11. 76 FR 20976 - Wireline Competition Bureau Releases 2011 Annual Telecommunications Reporting Worksheet (FCC Form...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-14

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION Wireline Competition Bureau Releases 2011 Annual Telecommunications Reporting Worksheet (FCC Form... Reporting Worksheet (FCC Form 499-A) and accompanying instructions. Filers may now submit their FCC Form...

  12. Cross linking molecular systems to form ultrathin dielectric layers

    NASA Astrophysics Data System (ADS)

    Feng, Danqin

    Dehydrogenation leads to cross linking of polymer or polymer like formation in very different systems: self-assembled monolayers and in closo -carboranes leading to the formation of semiconducting and dielectric boron carbide. We find evidence of intermolecular interactions for a self-assembled monolayer (SAM) formed from a large molecular adsorbate, [1,1';4',1"-terphenyl]-4,4"-dimethanethiol, from the dispersion of the molecular orbitals with changing the wave vector k and from the changes with temperature. With the formation self assembled molecular (SAM) layer, the molecular orbitals hybridize to electronic bands, with indications of significant band dispersion of the unoccupied molecular orbitals. Although organic adsorbates and thin films are generally regarded as "soft" materials, the effective Debye temperature, indicative of the dynamic motion of the lattice normal to the surface, can be very high, e.g. in the multilayer film formed from [1,1'-biphenyl]-4,4'-dimethanethiol (BPDMT). Depending on molecular orientation, the effective Debye temperature can be comparable to that of graphite due to the 'stiffness' of the benzene rings, but follows the expected Debye-Waller behavior for the core level photoemission intensities with temperature. This is not always the case. We find that a monomolecular film formed from [1,1';4',1"-terphenyl]-4,4"-dimethanethiol deviates from Debye-Waller temperature behavior and is likely caused by temperature dependent changes in molecular orientation. We also find evidence for the increase in dielectric character with polymerization (cross-linking) in spite of the decrease in the HOMO-LUMO gap upon irradiation of TPDMT. The changes in the HOMO-LUMO gap, with cross-linking, are roughly consistent with the band dispersion. The decomposition and cross-linking processes are also accompanied by changes in molecular orientation. The energetics of the three isomeric carborane cage compounds [ closo-1,2-orthocarborane, closo-1

  13. Linking the evolution and form of warning coloration in nature

    PubMed Central

    Stevens, Martin; Ruxton, Graeme D.

    2012-01-01

    Many animals are toxic or unpalatable and signal this to predators with warning signals (aposematism). Aposematic appearance has long been a classical system to study predator–prey interactions, communication and signalling, and animal behaviour and learning. The area has received considerable empirical and theoretical investigation. However, most research has centred on understanding the initial evolution of aposematism, despite the fact that these studies often tell us little about the form and diversity of real warning signals in nature. In contrast, less attention has been given to the mechanistic basis of aposematic markings; that is, ‘what makes an effective warning signal?’, and the efficacy of warning signals has been neglected. Furthermore, unlike other areas of adaptive coloration research (such as camouflage and mate choice), studies of warning coloration have often been slow to address predator vision and psychology. Here, we review the current understanding of warning signal form, with an aim to comprehend the diversity of warning signals in nature. We present hypotheses and suggestions for future work regarding our current understanding of several inter-related questions covering the form of warning signals and their relationship with predator vision, learning, and links to broader issues in evolutionary ecology such as mate choice and speciation. PMID:22113031

  14. Linking the evolution and form of warning coloration in nature.

    PubMed

    Stevens, Martin; Ruxton, Graeme D

    2012-02-01

    Many animals are toxic or unpalatable and signal this to predators with warning signals (aposematism). Aposematic appearance has long been a classical system to study predator-prey interactions, communication and signalling, and animal behaviour and learning. The area has received considerable empirical and theoretical investigation. However, most research has centred on understanding the initial evolution of aposematism, despite the fact that these studies often tell us little about the form and diversity of real warning signals in nature. In contrast, less attention has been given to the mechanistic basis of aposematic markings; that is, 'what makes an effective warning signal?', and the efficacy of warning signals has been neglected. Furthermore, unlike other areas of adaptive coloration research (such as camouflage and mate choice), studies of warning coloration have often been slow to address predator vision and psychology. Here, we review the current understanding of warning signal form, with an aim to comprehend the diversity of warning signals in nature. We present hypotheses and suggestions for future work regarding our current understanding of several inter-related questions covering the form of warning signals and their relationship with predator vision, learning, and links to broader issues in evolutionary ecology such as mate choice and speciation.

  15. Analysis of quasifission competition in fusion reactions forming heavy nuclei

    NASA Astrophysics Data System (ADS)

    Hammerton, Kalee; Kohley, Zachary; Morrissey, Dave; Wakhle, Aditya; Stiefel, Krystin; Hinde, David; Dasgupta, Mahananda; Williams, Elizabeth; Simenel, Cedric; Carter, Ian; Cook, Kaitlin; Jeung, Dongyun; Luong, Duc Huy; McNeil, Steven; Palshetkar, Chandani; Rafferty, Dominic

    2015-10-01

    Heavy-ion fusion reactions have provided a mechanism for the production of superheavy elements allowing for the extension of both the periodic table and chart of the nuclides. However, fusion of the projectile and target, forming a compound nucleus, is hindered by orders of magnitude by the quasifission process in heavy systems. In order to fully understand this mechanism, and make accurate predictions for superheavy element production cross sections, a clear description of the interplay between the fusion-fission and quasifission reaction channels is necessary. The mass-angle distributions of fragments formed in 8 different Cr + W reactions were measured at the Australia National University in order to explore the N/Z dependence of the quasifission process. Two sets of data were measured: one at a constant energy relative to the fusion barrier and one at a constant compound nucleus excitation energy. The results of this analysis will provide insight into the effect of using more neutron-rich beams in superheavy element production reactions.

  16. [Development of direct competitive enzyme-linked immunosorbent assay for the determination of domoic acid].

    PubMed

    Wang, Qian; Cheng, Jin-Ping; Gao, Li-Li; Dong, Yu; Xi, Lei

    2012-02-01

    To develop a direct competitive enzyme-linked immunosorbent assay (ELISA) for rapid detection of domoic acid concentrations, HRP (horse radish peroxidase) was successfully linked to DA using EDC. The concentration of DA was quantitatively analyzed on the basic of the specific immune responses between the DA- HRP and the monoclonal antibodies made in advance. Calibration curve were established after the optimization of reaction conditions such as the type of blocking solution, the blocking time and the incubation temperature. The results show that, the best reaction condition of the direct competitive ELISA is 1% gelatin, blocking 1 h at 37 degrees C, incubating 1 h at 37 degrees C after the monoclonal antibodies added. The detect limit is 3.58 ng x mL(-1), the coefficient of variation between the holes is below 15%, and the recovery is 80% - 120%. The whole analysis process could be completed within 1.5 h. It meets the requirements of rapid and batch detection of domoic acid. The method will have broad development prospects.

  17. [Development of direct competitive enzyme-linked immunosorbent assay for the determination of domoic acid].

    PubMed

    Wang, Qian; Cheng, Jin-Ping; Gao, Li-Li; Dong, Yu; Xi, Lei

    2012-02-01

    To develop a direct competitive enzyme-linked immunosorbent assay (ELISA) for rapid detection of domoic acid concentrations, HRP (horse radish peroxidase) was successfully linked to DA using EDC. The concentration of DA was quantitatively analyzed on the basic of the specific immune responses between the DA- HRP and the monoclonal antibodies made in advance. Calibration curve were established after the optimization of reaction conditions such as the type of blocking solution, the blocking time and the incubation temperature. The results show that, the best reaction condition of the direct competitive ELISA is 1% gelatin, blocking 1 h at 37 degrees C, incubating 1 h at 37 degrees C after the monoclonal antibodies added. The detect limit is 3.58 ng x mL(-1), the coefficient of variation between the holes is below 15%, and the recovery is 80% - 120%. The whole analysis process could be completed within 1.5 h. It meets the requirements of rapid and batch detection of domoic acid. The method will have broad development prospects. PMID:22509610

  18. Linked Data: Forming Partnerships at the Data Layer

    NASA Astrophysics Data System (ADS)

    Shepherd, A.; Chandler, C. L.; Arko, R. A.; Jones, M. B.; Hitzler, P.; Janowicz, K.; Krisnadhi, A.; Schildhauer, M.; Fils, D.; Narock, T.; Groman, R. C.; O'Brien, M.; Patton, E. W.; Kinkade, D.; Rauch, S.

    2015-12-01

    The challenges presented by big data are straining data management software architectures of the past. For smaller existing data facilities, the technical refactoring of software layers become costly to scale across the big data landscape. In response to these challenges, data facilities will need partnerships with external entities for improved solutions to perform tasks such as data cataloging, discovery and reuse, and data integration and processing with provenance. At its surface, the concept of linked open data suggests an uncalculated altruism. Yet, in his concept of five star open data, Tim Berners-Lee explains the strategic costs and benefits of deploying linked open data from the perspective of its consumer and producer - a data partnership. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) addresses some of the emerging needs of its research community by partnering with groups doing complementary work and linking their respective data layers using linked open data principles. Examples will show how these links, explicit manifestations of partnerships, reduce technical debt and provide a swift flexibility for future considerations.

  19. Competition.

    PubMed

    Chambers, D W

    1997-01-01

    Our ambivalence toward competition can be traced to an unspoken preference for certain types of competition which give us an advantage over the types we value less. Four types are defined (a) pure (same rules, same objectives), (b) collaborative (same rules, shared objective), (c) market share (different rules, same objectives), and (d) market growth (different rules, value added orientation). The defining characteristics of the four types of competition are respectively: needing a referee, arguing over the spoils, differentiation and substitutability, and customer focus. Dentistry has features of all four types of competition, thus making it difficult to have a meaningful discussion or frame a coherent policy on this topic.

  20. Enhancing Technology Education by Forming Links with Industry: A New Zealand Case Study

    ERIC Educational Resources Information Center

    Brunton, Margaret; Coll, Richard K.

    2005-01-01

    The New Zealand technology curriculum suggests that schools should seek to develop links with industry as a means of providing real-world examples of technology practice. However, if a school is to form links, what form might such links take, and with whom should they be made? The case study research reported here represents an investigation into…

  1. Biotin-Streptavidin Competition Mediates Sensitive Detection of Biomolecules in Enzyme Linked Immunosorbent Assay

    PubMed Central

    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. PMID:26954237

  2. Biotin-Streptavidin Competition Mediates Sensitive Detection of Biomolecules in Enzyme Linked Immunosorbent Assay.

    PubMed

    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. PMID:26954237

  3. Quantification of Sorafenib in Human Serum by Competitive Enzyme-Linked Immunosorbent Assay.

    PubMed

    Saita, Tetsuya; Yamamoto, Yuta; Noda, Satoshi; Shioya, Makoto; Hira, Daiki; Andoh, Akira; Morita, Shin-Ya; Terada, Tomohiro; Shin, Masashi

    2015-01-01

    The multikinase inhibitor sorafenib has been used in the treatment of hepatocellular carcinoma, renal cell carcinoma, and differentiated thyroid carcinoma. Here we have demonstrated the production of the first specific antibody against sorafenib. Anti-sorafenib serum was obtained by immunizing mice with an antigen conjugated with bovine serum albumin and carboxylic modified 4-(4-aminophenoxy)-N-methyl-2-pyridinecarboxamide (AMPC) using the N-succinimidyl ester method. Enzyme labeling of sorafenib with horseradish peroxidase was similarly performed using carboxylic modified AMPC. A simple competitive enzyme-linked immunosorbent assay (ELISA) for sorafenib was developed using the principle of direct competition between sorafenib and the enzyme marker for anti-sorafenib antibody, which had been adsorbed by the plastic surface of a microtiter plate. Serum sorafenib concentrations lower than 0.04 µg/mL were reproducibly measurable using the ELISA. This ELISA was specific to sorafenib and showed very slight cross-reactivity (2.5%) with a major metabolite, sorafenib N-oxide. The values of serum sorafenib levels from 32 patients measured by this ELISA were comparable with those measured by HPLC, and there was a strong correlation between the values determined by the two methods (Y=1.016X-0.137, r=0.979). The specificity and sensitivity of the ELISA for sorafenib should provide a valuable new tool for use in therapeutic drug monitoring and pharmacokinetic studies of sorafenib. PMID:26521829

  4. Quantification of Sorafenib in Human Serum by Competitive Enzyme-Linked Immunosorbent Assay.

    PubMed

    Saita, Tetsuya; Yamamoto, Yuta; Noda, Satoshi; Shioya, Makoto; Hira, Daiki; Andoh, Akira; Morita, Shin-Ya; Terada, Tomohiro; Shin, Masashi

    2015-01-01

    The multikinase inhibitor sorafenib has been used in the treatment of hepatocellular carcinoma, renal cell carcinoma, and differentiated thyroid carcinoma. Here we have demonstrated the production of the first specific antibody against sorafenib. Anti-sorafenib serum was obtained by immunizing mice with an antigen conjugated with bovine serum albumin and carboxylic modified 4-(4-aminophenoxy)-N-methyl-2-pyridinecarboxamide (AMPC) using the N-succinimidyl ester method. Enzyme labeling of sorafenib with horseradish peroxidase was similarly performed using carboxylic modified AMPC. A simple competitive enzyme-linked immunosorbent assay (ELISA) for sorafenib was developed using the principle of direct competition between sorafenib and the enzyme marker for anti-sorafenib antibody, which had been adsorbed by the plastic surface of a microtiter plate. Serum sorafenib concentrations lower than 0.04 µg/mL were reproducibly measurable using the ELISA. This ELISA was specific to sorafenib and showed very slight cross-reactivity (2.5%) with a major metabolite, sorafenib N-oxide. The values of serum sorafenib levels from 32 patients measured by this ELISA were comparable with those measured by HPLC, and there was a strong correlation between the values determined by the two methods (Y=1.016X-0.137, r=0.979). The specificity and sensitivity of the ELISA for sorafenib should provide a valuable new tool for use in therapeutic drug monitoring and pharmacokinetic studies of sorafenib.

  5. Structured landscapes formed by competition between forest, peat forming wetlands, and rivers.

    NASA Astrophysics Data System (ADS)

    van der Velde, Ype; Temme, Arnaud

    2016-04-01

    Fresh water is crucial for society and ecosystems. However, our ability to secure fresh water resources under climatic and anthropogenic change is impaired by the complexity of interactions between human society, ecosystems, soils, and topography. These interactions cause landscape properties to co-evolve, continuously changing the flow paths of water through the landscape. Such co-evolution driven flow path changes are, to-date, poorly understood. In this presentation we investigate hydrological interactions and feedbacks within a boreal landscape with forests, peat forming wetlands and rivers during the holocene. We introduce a spatially distributed landscape co-evolution model that simulates interactions between vegetation, soil organic matter, groundwater and rivers under a wide range of climates. Typical interactions of this model are that a denser vegetation (forest) evaporates more than the low biomass vegetation of a wetland, making the forest dryer and the wetland wetter. Wet conditions favour peat formation with a high water content that further reduces groundwater fluctuations, making the landscape even more wet. At the same time these wet condition cause runoff creating incising rivers that drain the peat and favour tree growth. To understand how positive and stabilizing feedbacks within the model structure form complex landscape patterns of forests, peat forming wetlands and rivers, we stepwise increase spatial connectivity within the model. This setup allows us to untangle the effects of climate, groundwater flow and stream erosion on landscape patterns and better understand observed landscape patterns.

  6. Competitive interactions between corals and turf algae depend on coral colony form.

    PubMed

    Swierts, Thomas; Vermeij, Mark Ja

    2016-01-01

    Turf algae are becoming more abundant on coral reefs worldwide, but their effects on other benthic organisms remain poorly described. To describe the general characteristics of competitive interactions between corals and turf algae, we determined the occurrence and outcomes of coral-turf algal interactions among different coral growth forms (branching, upright, massive, encrusting, plating, and solitary) on a shallow reef in Vietnam. In total, the amount of turf algal interaction, i.e., the proportion of the coral boundary directly bordering turf algae, was quantified for 1,276 coral colonies belonging to 27 genera and the putative outcome of each interaction was noted. The amount of turf algal interaction and the outcome of these interactions differed predictably among the six growth forms. Encrusting corals interacted most often with turf algae, but also competed most successfully against turf algae. The opposite was observed for branching corals, which rarely interacted with turf algae and rarely won these competitive interactions. Including all other growth forms, a positive relationship was found between the amount of competitive interactions with neighboring turf algae and the percentage of such interaction won by the coral. This growth form dependent ability to outcompete turf algae was not only observed among coral species, but also among different growth forms in morphologically plastic coral genera (Acropora, Favia, Favites, Montastrea, Montipora, Porites) illustrating the general nature of this relationship. PMID:27190707

  7. Competitive interactions between corals and turf algae depend on coral colony form

    PubMed Central

    Vermeij, Mark JA

    2016-01-01

    Turf algae are becoming more abundant on coral reefs worldwide, but their effects on other benthic organisms remain poorly described. To describe the general characteristics of competitive interactions between corals and turf algae, we determined the occurrence and outcomes of coral–turf algal interactions among different coral growth forms (branching, upright, massive, encrusting, plating, and solitary) on a shallow reef in Vietnam. In total, the amount of turf algal interaction, i.e., the proportion of the coral boundary directly bordering turf algae, was quantified for 1,276 coral colonies belonging to 27 genera and the putative outcome of each interaction was noted. The amount of turf algal interaction and the outcome of these interactions differed predictably among the six growth forms. Encrusting corals interacted most often with turf algae, but also competed most successfully against turf algae. The opposite was observed for branching corals, which rarely interacted with turf algae and rarely won these competitive interactions. Including all other growth forms, a positive relationship was found between the amount of competitive interactions with neighboring turf algae and the percentage of such interaction won by the coral. This growth form dependent ability to outcompete turf algae was not only observed among coral species, but also among different growth forms in morphologically plastic coral genera (Acropora, Favia, Favites, Montastrea, Montipora, Porites) illustrating the general nature of this relationship. PMID:27190707

  8. Competitive interactions between corals and turf algae depend on coral colony form.

    PubMed

    Swierts, Thomas; Vermeij, Mark Ja

    2016-01-01

    Turf algae are becoming more abundant on coral reefs worldwide, but their effects on other benthic organisms remain poorly described. To describe the general characteristics of competitive interactions between corals and turf algae, we determined the occurrence and outcomes of coral-turf algal interactions among different coral growth forms (branching, upright, massive, encrusting, plating, and solitary) on a shallow reef in Vietnam. In total, the amount of turf algal interaction, i.e., the proportion of the coral boundary directly bordering turf algae, was quantified for 1,276 coral colonies belonging to 27 genera and the putative outcome of each interaction was noted. The amount of turf algal interaction and the outcome of these interactions differed predictably among the six growth forms. Encrusting corals interacted most often with turf algae, but also competed most successfully against turf algae. The opposite was observed for branching corals, which rarely interacted with turf algae and rarely won these competitive interactions. Including all other growth forms, a positive relationship was found between the amount of competitive interactions with neighboring turf algae and the percentage of such interaction won by the coral. This growth form dependent ability to outcompete turf algae was not only observed among coral species, but also among different growth forms in morphologically plastic coral genera (Acropora, Favia, Favites, Montastrea, Montipora, Porites) illustrating the general nature of this relationship.

  9. Competition with and without priority control: linking rivalry to attention through winner-take-all networks with memory

    PubMed Central

    Marx, Svenja; Gruenhage, Gina; Walper, Daniel; Rutishauser, Ueli; Einhäuser, Wolfgang

    2015-01-01

    Competition is ubiquitous in perception. For example, items in the visual field compete for processing resources, and attention controls their priority (biased competition). The inevitable ambiguity in the interpretation of sensory signals yields another form of competition: distinct perceptual interpretations compete for access to awareness. Rivalry, where two equally likely percepts compete for dominance, explicates the latter form of competition. Building upon the similarity between attention and rivalry, we propose to model rivalry by a generic competitive circuit that is widely used in the attention literature—a winner-take-all (WTA) network. Specifically, we show that a network of two coupled WTA circuits replicates three common hallmarks of rivalry: the distribution of dominance durations, their dependence on input strength (“Levelt's propositions”), and the effects of stimulus removal (blanking). This model introduces a form of memory by forming discrete states and explains experimental data better than competitive models of rivalry without memory. This result supports the crucial role of memory in rivalry specifically and in competitive processes in general. Our approach unifies the seemingly distinct phenomena of rivalry, memory, and attention in a single model with competition as the common underlying principle. PMID:25581077

  10. Competitiveness

    NASA Astrophysics Data System (ADS)

    Minihan, Charles E.

    1991-03-01

    Competition is defined as a spirited, sometimes ruthless, engagement of rivals such as in a race, a match, or an effort by one person to sell goods or services to customers in the marketplace of another. Sound familiar? If you will bear with me for a few minutes, I would like to examine competitiveness on a more global basis with emphasis on the rules of the game. You may be thinking that more often than not the competitive arena is relatively small and far from global, and its consequences are singularly influential on a trivial document called the P & L. However, with the newly established freedom of a major segment of the world population and with the industrial capability formerly known as Communist moving into what has heretofore been "our" limited arena, the competition could get very brisk. Brisk, and perhaps ruthless, unless we work together to try to establish an international industrial policy that is truly based on equality of competitive opportunity for all.

  11. Competition between links in "producer-consumer" trophic chains in an aquatic closed system with spatially separated components.

    PubMed

    Pisman, T I; Pechurkin, N S; Somova, L A

    2001-01-01

    The work analyzes functioning of a "producer-consumer" closed aquatic system with spatially separated links, where each component consisted of two species. Producers in the system were the microalgae of Chlorella vulgaris and Scenedesmus sp., consumers--Paramecium caudatum infusoria and Brachionus sp. rotifers. In the experiment the competing predators were consuming on a mixed culture of algae, and the competition of algae was studied under nitrogen limitation. Under these conditions competitiveness of Scenedesmus was higher than that of Chlorella vulgaris. Metabolism products of Scenedesmus algae have been found to have negative effect on reproduction of Paramecium caudatum protozoa. Predator population dynamics in the "consumer" link demonstrated that the rotifers that consume two algal species are more competitive compared to protozoa feeding on chlorella only. Grant numbers: N99-04-96017, N25.

  12. Competition between links in "producer-consumer" trophic chains in an aquatic closed system with spatially separated components.

    PubMed

    Pisman, T I; Pechurkin, N S; Somova, L A

    2001-01-01

    The work analyzes functioning of a "producer-consumer" closed aquatic system with spatially separated links, where each component consisted of two species. Producers in the system were the microalgae of Chlorella vulgaris and Scenedesmus sp., consumers--Paramecium caudatum infusoria and Brachionus sp. rotifers. In the experiment the competing predators were consuming on a mixed culture of algae, and the competition of algae was studied under nitrogen limitation. Under these conditions competitiveness of Scenedesmus was higher than that of Chlorella vulgaris. Metabolism products of Scenedesmus algae have been found to have negative effect on reproduction of Paramecium caudatum protozoa. Predator population dynamics in the "consumer" link demonstrated that the rotifers that consume two algal species are more competitive compared to protozoa feeding on chlorella only. Grant numbers: N99-04-96017, N25. PMID:11695442

  13. Competition between links in ``producer-consumer'' trophic chains in an aquatic closed system with spatially separated components

    NASA Astrophysics Data System (ADS)

    Pisman, T. I.; Pechurkin, N. S.; Somova, L. A.

    The work analyzes functioning of a "producer-consumer" closed aquatic system with spatially separated links, where each component consisted of two species. Producers in the system were the microalgae of Chlorella vulgaris and Scenedesmus sp., consumers - Paramecium caudatum infusoria and Brachionus sp. rotifers. In the experiment the competing predators were consuming on a mixed culture of algae, and the competition of algae was studied under nitrogen limitation. Under these conditions competitiveness of Scenedesmus was higher than that of Chlorella vulgaris. Metabolism products of Scenedesmus algae have been found to have negative effect on reproduction of Paramecium caudatum protozoa. Predator population dynamics in the "consumer" link demonstrated that the rotifers that consume two algal species are more competitive compared to protozoa feeding on chlorella only.

  14. Changed Clonal Growth Form Induced by Sand Burial Facilitates the Acclimation of Carex brevicuspis to Competition

    PubMed Central

    Li, Feng; Xie, Yonghong; Zhu, Lianlian; Jiang, Li; Chen, Xinsheng; Pan, Baihan; Deng, Zhengmiao

    2015-01-01

    guerrilla growth form and spacer elongation induced by sand burial helped C. brevicuspis to acclimate to competition. PMID:25822734

  15. Changed clonal growth form induced by sand burial facilitates the acclimation of Carex brevicuspis to competition.

    PubMed

    Li, Feng; Xie, Yonghong; Zhu, Lianlian; Jiang, Li; Chen, Xinsheng; Pan, Baihan; Deng, Zhengmiao

    2015-01-01

    guerrilla growth form and spacer elongation induced by sand burial helped C. brevicuspis to acclimate to competition.

  16. The form of a trade-off determines the response to competition.

    PubMed

    Maharjan, Ram; Nilsson, Susanna; Sung, Judy; Haynes, Ken; Beardmore, Robert E; Hurst, Laurence D; Ferenci, Tom; Gudelj, Ivana

    2013-10-01

    Understanding how populations and communities respond to competition is a central concern of ecology. A seminal theoretical solution first formalised by Levins (and re-derived in multiple fields) showed that, in theory, the form of a trade-off should determine the outcome of competition. While this has become a central postulate in ecology it has evaded experimental verification, not least because of substantial technical obstacles. We here solve the experimental problems by employing synthetic ecology. We engineer strains of Escherichia coli with fixed resource allocations enabling accurate measurement of trade-off shapes between bacterial survival and multiplication in multiple environments. A mathematical chemostat model predicts different, and experimentally verified, trajectories of gene frequency changes as a function of condition-specific trade-offs. The results support Levins' postulate and demonstrates that otherwise paradoxical alternative outcomes witnessed in subtly different conditions are predictable.

  17. A competitive enzyme-linked immunosorbent assay for determination of chloramphenicol.

    PubMed

    Wesongah, J O; Murilla, G A; Guantai, A N; Elliot, C; Fodey, T; Cannavan, A

    2007-02-01

    Chloramphenicol is a broad-spectrum antibiotic shown to have specific activity against a wide variety of organisms that are causative agents of several disease conditions in domestic animals. Chloramphenicol has been banned for use in food-producing animals for its serious adverse toxic effects in humans. Due to the harmful effects of chloramphenicol residues livestock products should be free of any traces of these residues. Several analytical methods are available for chloramphenicol analysis but sensitive methods are required in order to ensure that no traces of chloramphenicol residues are present in edible animal products. In order to prevent the illegal use of chloramphenicol, regulatory control of its residues in food of animal origin is essential. A competitive enzyme-linked immunosorbent assay for chloramphenicol has been locally developed and optimized for the detection of chloramphenicol in sheep serum. In the assay, chloramphenicol in the test samples and that in chloramphenicol-horseradish peroxidase conjugate compete for antibodies raised against the drug in camels and immobilized on a microtitre plate. Tetramethylbenzidine-hydrogen peroxide (TMB/H2O2) is used as chromogen-substrate system. The assay has a detection limit of 0.1 ng/mL of serum with a high specificity for chloramphenicol. Cross-reactivity with florfenicol, thiamphenicol, penicillin, tetracyclines and sulfamethazine was not observed. The assay was able to detect chloramphenicol concentrations in normal sheep serum for at least 1 week after intramuscular injection with the drug at a dose of 25 mg/kg body weight (b.w.). The assay can be used as a screening tool for chloramphenicol use in animals. PMID:17217404

  18. Appearance- and Competition-Focused Performance Goals: Examining Their Links with Performance in Physical Education

    ERIC Educational Resources Information Center

    Warburton, Victoria; Spray, Christopher

    2014-01-01

    We examined the utility of distinguishing between appearance- and competition-focused approach and avoidance performance goals to our understanding of motivation in physical education. Four achievement goals were tested composed of approach-avoidance and appearance-competition components. Three hundred and two pupils, aged 11-14 years, completed…

  19. Theorizing Strategic Human Resource Development: Linking Financial Performance and Sustainable Competitive Advantage

    ERIC Educational Resources Information Center

    Hu, Po

    2007-01-01

    This paper is to explore potential new underlying theory of strategic human resource development based on critiques of current theoretical foundations of HRD. It offers a new definition and model of Strategic HRD based on resource-based view of firm and human resource, with linkage to financial performance and competitiveness. Proposed new model…

  20. A competitive enzyme-linked immunosorbent assay for quantification of tetrastatin in body fluids and tumor extracts.

    PubMed

    Dupont-Deshorgue, A; Oudart, J B; Brassart, B; Deslee, G; Perotin, J M; Diebold, M D; Monboisse, J C; Ramont, L; Brassart-Pasco, S

    2015-08-01

    Basement membrane collagens or derived fragments are measured in biological fluids such as blood and urine of patients and appear to be useful for diagnosis, prognostication, or treatment monitoring as proposed for endostatin, a fragment of collagen XVIII, or tumstatin, a fragment of collagen IV. Tetrastatin, the NC1 alpha 4 collagen IV domain, was previously reported to inhibit tumor growth and angiogenesis. The aim of this study was to develop and validate a method to measure tetrastatin concentrations in human fluids. We developed a competitive enzyme-linked immunosorbent assay (ELISA). It allowed measuring tetrastatin levels in human serum, bronchial aspiration and bronchoalveolar lavage fluids, and lung tissue extracts. The tetrastatin level was significantly higher in tumor tissues than in healthy lung tissues. Tetrastatin competitive ELISA could be useful to quantify tetrastatin in tissues and biological fluids for the diagnosis or prognostication of diseases in which basement membrane metabolism may be altered, especially tumor progression. PMID:25935259

  1. Auxin transport through PIN-FORMED 3 (PIN3) controls shade avoidance and fitness during competition.

    PubMed

    Keuskamp, Diederik H; Pollmann, Stephan; Voesenek, Laurentius A C J; Peeters, Anton J M; Pierik, Ronald

    2010-12-28

    Plants grow in dense vegetations at the risk of being out-competed by neighbors. To increase their competitive power, plants display adaptive responses, such as rapid shoot elongation (shade avoidance) to consolidate light capture. These responses are induced upon detection of proximate neighbors through perception of the reduced ratio between red (R) and far-red (FR) light that is typical for dense vegetations. The plant hormone auxin is a central regulator of plant development and plasticity, but until now it has been unknown how auxin transport is controlled to regulate shade-avoidance responses. Here, we show that low R:FR detection changes the cellular location of the PIN-FORMED 3 (PIN3) protein, a regulator of auxin efflux, in Arabidopsis seedlings. As a result, auxin levels in the elongating hypocotyls are increased under low R:FR. Seedlings of the pin3-3 mutant lack this low R:FR-induced increase of endogenous auxin in the hypocotyl and, accordingly, have no elongation response to low R:FR. We hypothesize that low R:FR-induced stimulation of auxin biosynthesis drives the regulation of PIN3, thus allowing shade avoidance to occur. The adaptive significance of PIN3-mediated control of shade-avoidance is shown in plant competition studies. It was found that pin3 mutants are outcompeted by wild-type neighbors who suppress fitness of pin3-3 by 40%. We conclude that low R:FR modulates the auxin distribution by a change in the cellular location of PIN3, and that this control can be of great importance for plants growing in dense vegetations.

  2. Strategy and society: the link between competitive advantage and corporate social responsibility.

    PubMed

    Porter, Michael E; Kramer, Mark R

    2006-12-01

    Governments, activists, and the media have become adept at holding companies to account for the social consequences of their actions. In response, corporate social responsibility has emerged as an inescapable priority for business leaders in every country. Frequently, though, CSR efforts are counterproductive, for two reasons. First, they pit business against society, when in reality the two are interdependent. Second, they pressure companies to think of corporate social responsibility in generic ways instead of in the way most appropriate to their individual strategies. The fact is, the prevailing approaches to CSR are so disconnected from strategy as to obscure many great opportunities for companies to benefit society. What a terrible waste. If corporations were to analyze their opportunities for social responsibility using the same frameworks that guide their core business choices, they would discover, as Whole Foods Market, Toyota, and Volvo have done, that CSR can be much more than a cost, a constraint, or a charitable deed--it can be a potent source of innovation and competitive advantage. In this article, Michael Porter and Mark Kramer propose a fundamentally new way to look at the relationship between business and society that does not treat corporate growth and social welfare as a zero-sum game. They introduce a framework that individual companies can use to identify the social consequences of their actions; to discover opportunities to benefit society and themselves by strengthening the competitive context in which they operate; to determine which CSR initiatives they should address; and to find the most effective ways of doing so. Perceiving social responsibility as an opportunity rather than as damage control or a PR campaign requires dramatically different thinking--a mind-set, the authors warn, that will become increasingly important to competitive success. PMID:17183795

  3. Strategy and society: the link between competitive advantage and corporate social responsibility.

    PubMed

    Porter, Michael E; Kramer, Mark R

    2006-12-01

    Governments, activists, and the media have become adept at holding companies to account for the social consequences of their actions. In response, corporate social responsibility has emerged as an inescapable priority for business leaders in every country. Frequently, though, CSR efforts are counterproductive, for two reasons. First, they pit business against society, when in reality the two are interdependent. Second, they pressure companies to think of corporate social responsibility in generic ways instead of in the way most appropriate to their individual strategies. The fact is, the prevailing approaches to CSR are so disconnected from strategy as to obscure many great opportunities for companies to benefit society. What a terrible waste. If corporations were to analyze their opportunities for social responsibility using the same frameworks that guide their core business choices, they would discover, as Whole Foods Market, Toyota, and Volvo have done, that CSR can be much more than a cost, a constraint, or a charitable deed--it can be a potent source of innovation and competitive advantage. In this article, Michael Porter and Mark Kramer propose a fundamentally new way to look at the relationship between business and society that does not treat corporate growth and social welfare as a zero-sum game. They introduce a framework that individual companies can use to identify the social consequences of their actions; to discover opportunities to benefit society and themselves by strengthening the competitive context in which they operate; to determine which CSR initiatives they should address; and to find the most effective ways of doing so. Perceiving social responsibility as an opportunity rather than as damage control or a PR campaign requires dramatically different thinking--a mind-set, the authors warn, that will become increasingly important to competitive success.

  4. A Direct, Competitive Enzyme-Linked Immunosorbent Assay (ELISA) as a Quantitative Technique for Small Molecules

    ERIC Educational Resources Information Center

    Powers, Jennifer L.; Rippe, Karen Duda; Imarhia, Kelly; Swift, Aileen; Scholten, Melanie; Islam, Naina

    2012-01-01

    ELISA (enzyme-linked immunosorbent assay) is a widely used technique with applications in disease diagnosis, detection of contaminated foods, and screening for drugs of abuse or environmental contaminants. However, published protocols with a focus on quantitative detection of small molecules designed for teaching laboratories are limited. A…

  5. Electrathon Competition: A Technology Club's Most Successful Project Links School and Industry

    ERIC Educational Resources Information Center

    Copes, Brian

    2005-01-01

    In this article, the author talks about his most successful electric vehicle project that links school and industry. Some people in the public school arena stereotype industrial technology as a dumping ground for underachieving students, and many of his students believed that they could not succeed in higher education classes. He challenged…

  6. Effects of Decabromodiphenyl Ether (BDE-209) on Inter-Specific Competition between Two Species of Marine Bloom-Forming Microalgae

    PubMed Central

    Zhang, Xinxin; Tang, Xuexi; Zhou, Bin; Wang, You

    2013-01-01

    Decabromodiphenyl ether (BDE-209), a new kind of persistent organic pollutants, was selected to investigate its influence on population growth and inter-specific competition between two species of marine bloom-forming microalgae, Heterosigma akashiwo and Karenia mikimotoi. (1)BDE-209 showed acute toxic effects on both microalgae and H. akashiwo was more sensitive from view of 96 h-EC50 and the ultrastructure variation. (2)The microalgal population growth patterns in mono-culture were density-dependent and the growth of both species in the normal co-culture was significantly depressed by competition (P<0.05) with different initial biomass ratios. BDE-209 exposure significantly changed the growth. (3) Lotka-Volterra competition model was used to simulate the interaction between the microalgae. BDE-209 exposure broke the competitive balance to make competition gradually shift in favor of H. akashiwo. Results suggested BDE-209 did have toxic effects on either microalgal growth or the inter-specific competition, which was quite different from previous reports. Further exploration of the mechanism is needed. PMID:23555557

  7. Interactive processes link the multiple symptoms of fatigue in sport competition.

    PubMed

    Knicker, Axel J; Renshaw, Ian; Oldham, Anthony R H; Cairns, Simeon P

    2011-04-01

    Muscle physiologists often describe fatigue simply as a decline of muscle force and infer this causes an athlete to slow down. In contrast, exercise scientists describe fatigue during sport competition more holistically as an exercise-induced impairment of performance. The aim of this review is to reconcile the different views by evaluating the many performance symptoms/measures and mechanisms of fatigue. We describe how fatigue is assessed with muscle, exercise or competition performance measures. Muscle performance (single muscle test measures) declines due to peripheral fatigue (reduced muscle cell force) and/or central fatigue (reduced motor drive from the CNS). Peak muscle force seldom falls by >30% during sport but is often exacerbated during electrical stimulation and laboratory exercise tasks. Exercise performance (whole-body exercise test measures) reveals impaired physical/technical abilities and subjective fatigue sensations. Exercise intensity is initially sustained by recruitment of new motor units and help from synergistic muscles before it declines. Technique/motor skill execution deviates as exercise proceeds to maintain outcomes before they deteriorate, e.g. reduced accuracy or velocity. The sensation of fatigue incorporates an elevated rating of perceived exertion (RPE) during submaximal tasks, due to a combination of peripheral and higher CNS inputs. Competition performance (sport symptoms) is affected more by decision-making and psychological aspects, since there are opponents and a greater importance on the result. Laboratory based decision making is generally faster or unimpaired. Motivation, self-efficacy and anxiety can change during exercise to modify RPE and, hence, alter physical performance. Symptoms of fatigue during racing, team-game or racquet sports are largely anecdotal, but sometimes assessed with time-motion analysis. Fatigue during brief all-out racing is described biomechanically as a decline of peak velocity, along with altered

  8. Competition of bloom-forming marine phytoplankton at low nutrient concentrations.

    PubMed

    Hu, Hanhua; Zhang, Jun; Chen, Weidong

    2011-01-01

    Competition of three bloom-forming marine phytoplankton (diatom Skeletonema costatum, and dinoflagellates Prorocentrum minimum and Alexandrium tamarense) was studied through a series of multispecies cultures with different nitrate (NaNO3) and phosphate (NaH2PO4) levels and excess silicate to interpret red tide algae succession. S. costatum outgrew the other two dinoflagellates in nitrate and phosphate replete cultures with 10 micromol/L Na2SiO3. Under nitrate limited (8.82 micromol/L NaNO3) conditions, the growth of S. costatum was also dominant when phosphate concentrations were from 3.6 to 108 micromol/L. Cell density of the two dinoflagellates only increased slightly, to less than 400 and 600 cells/mL, respectively. Cell density of S. costatum decreased with time before day 12, and then increased to 4000 cells/mL (1.5 mg/L dry biomass) at NaNO3 concentrations between 88.2 and 882 micromol/L with limited phosphate (0.36 micromol/L NaH2PO4) levels. In addition, P. minimum grew well with a maximal cell density of 1690-2100 cells/mL (0.5-0.6 mg/L dry biomass). Although S. costatum initially grew fast, its cell density decreased quickly with time later in the growth phase and the two dinoflagellates were dominant under the nitrate-limited and high nitrate conditions with limited phosphate. These results indicated that the diatom was a poor competitor compared to the two dinoflagellates under limited phosphate; however, it grew well under limited nitrate when growth of the dinoflagellates was near detection limits. PMID:21793409

  9. The dark side of competition: How competitive behaviour and striving to avoid inferiority are linked to depression, anxiety, stress and self-harm.

    PubMed

    Gilbert, Paul; McEwan, Kirsten; Bellew, Rebecca; Mills, Alison; Gale, Corinne

    2009-06-01

    This study was guided by the social rank theory of depression and aimed to explore the relationship between depression, anxiety, stress and self-harm with striving to avoid inferiority, feelings of shame and styles of attachment. Participants diagnosed with depression (n = 62) completed a series of questionnaires measuring striving to avoid inferiority, fears of missing out, being overlooked and active rejection, attachment, social rank and psychopathologies. Striving to avoid inferiority was significantly linked to social rank variables and anxious attachment. Mediator analyses revealed that the relationship between striving to avoid inferiority and depression was mediated by the social rank variable of external shame, and also anxious attachment. These findings suggest that elevated competitive behaviour can have a 'dark side'. When people feel insecure in their social environments, it can focus them on a hierarchical view of themselves and others, with a fear of rejection if they feel they have become too inferior or subordinate. This may increase vulnerability to depression, anxiety and stress.

  10. Gene-environment interplay in the link of friends' and nonfriends' behaviors with children's social reticence in a competitive situation.

    PubMed

    Guimond, Fanny-Alexandra; Brendgen, Mara; Vitaro, Frank; Forget-Dubois, Nadine; Dionne, Ginette; Tremblay, Richard E; Boivin, Michel

    2014-03-01

    This study used a genetically informed design to assess the effects of friends' and nonfriends' reticent and dominant behaviors on children's observed social reticence in a competitive situation. Potential gene-environment correlations (rGE) and gene-environment interactions (GxE) in the link between (a) friends' and nonfriends' behaviors and (b) children's social reticence were examined. The sample comprised 466 twin children (i.e., the target children), each of whom was assessed in kindergarten together with a same-sex friend and two nonfriend classmates of either sex. Multilevel regression analyses revealed that children with a genetic disposition for social reticence showed more reticent behavior in the competitive situation and were more likely to affiliate with reticent friends (i.e., rGE). Moreover, a higher level of children's reticent behavior was predicted by their friends' higher social reticence (particularly for girls) and their friends' higher social dominance, independently of children's genetic disposition. Children's social reticence was also predicted by their nonfriends' behaviors. Specifically, children were less reticent when male nonfriends showed high levels of social reticence in the competitive situation, and this was particularly true for children with a genetic disposition for social reticence (i.e., GxE). Moreover, children genetically vulnerable for social reticence seemed to foster dominant behavior in their female nonfriend peers (i.e., rGE). In turn, male nonfriends seemed to be more dominant as soon as the target children were reticent, even if the target children did not have a stable genetic disposition for this behavior.

  11. A new competitive enzyme linked immunosorbent assay (MRP83-CA15-3) for MUC1 measurement in breast cancer.

    PubMed

    Mohammadnejad, J; Rasaee, Mohammad J; Saqhafi, B; Rajabibazl, M; Rahbarizadeh, F; Omidfar, K; Paknejad, M

    2006-01-01

    A new competitive enzyme linked immunosorbent assay was developed in this study. Monoclonal antibody (PR81) against the tandem repeat of the core protein was prepared, characterized, purified, and conjugated to HRP. This antibody exhibited no cross reactions with proteins such as bovine serum albumin, keyhole limpet homocyanin, human serum albumin, casein, human milk fat globin (HMFG), and peptone. The native cancerous MUC1 protein was purified from ascites fluid of a patient suffering from small cell lung carcinoma by immunoaffinity chromatography and used as a standard preparation in the assay buffer. The standard curve was constructed following a competitive procedure in the range of 0-200 U/mL. The level of MUC1 in normal and cancerous samples was compared following this procedure and using available CA15-3 EIA (Can Ag), as well as LIAISON CA15-3 commercial kits. The correlation coefficient between the procedure reported in this work (MRP83-CA15-3) and CA15-3 EIA (Can Ag) was 0.68 and was 0.95 with the LIAISON CA15-3 kit. We concluded that the present assay can detect MUC1 in breast cancer patients with great sensitivity and accuracy.

  12. Variability in sperm form and function in the context of sperm competition risk in two Tupinambis lizards

    PubMed Central

    Blengini, Cecilia S; Sergio, Naretto; Gabriela, Cardozo; Giojalas, Laura C; Margarita, Chiaraviglio

    2014-01-01

    In polyandrous species, sperm morphometry and sperm velocity are under strong sexual selection. Although several hypotheses have been proposed to explain the role of sperm competition in sperm trait variation, this aspect is still poorly understood. It has been suggested that an increase in sperm competition pressure could reduce sperm size variation or produce a diversity of sperm to maximize male fertilization success. We aim at elucidating the variability of sperm morphometric traits and velocity in two Tupinambis lizards in the context of sperm competition risk. Sperm traits showed substantial variation at all levels examined: between species, among males within species, and within the ejaculate of individual males. Sperm velocity was found to be positively correlated with flagellum: midpiece ratio, with relatively longer flagella associated with faster sperm. Our results document high variability in sperm form and function in lizards. PMID:25505535

  13. Evidence for X-linked introgression between molecular forms of Anopheles gambiae from Angola.

    PubMed

    Choi, K S; Townson, H

    2012-06-01

    The M and S molecular forms of the African malaria vector Anopheles gambiae (Diptera: Culicidae) are morphologically identical incipient species in which reproductive isolation is incomplete, enabling low-level gene flow between forms. In an attempt to find differences between the M and S forms, sequence variation was studied at loci along the X chromosome in adult female An. gambiae from Angola. A high proportion of M form specimens from Angola (79% of the 456 X chromosomes sampled) were found to contain a 16-bp insertion in intron 4 of the X-linked GPRCCK1 locus, relative to the AgamP3 release of the An. gambiae PEST genome sequence. The insertion was in Hardy-Weinberg equilibrium in Angolan M form populations. The same insertion was found in all S form specimens examined, regardless of where in Africa they were sampled, but was absent from a sample of M form specimens collected in Ghana, Bioko and Mali. In M form specimens from Angola, there was an association between alleles at the GPRCCK1 locus and those at a microsatellite locus, AGXH678, close to the centromere of the X chromosome, with significant linkage disequilibrium between loci separated by 0.472 Mbp (P < 0.033). We show that the insertion results from introgression from the S form into the M form, rather than from the retention of an ancestral character. Gene flow from the S to M form could allow genes of adaptive value to be transferred, including those conferring insecticide resistance and others influencing ecology and behaviour, and thus malaria transmission and control. We discuss factors that may have led to this introgression event.

  14. Models of genetic drift as limiting forms of the Lotka-Volterra competition model.

    PubMed

    Constable, George W A; McKane, Alan J

    2015-01-23

    The relationship between the Moran model and stochastic Lotka-Volterra competition (SLVC) model is explored via time scale separation arguments. For neutral systems the two are found to be equivalent at long times. For systems with selective pressure, their behavior differs. It is argued that the SLVC is preferable to the Moran model since in the SLVC population size is regulated by competition, rather than arbitrarily fixed as in the Moran model. As a consequence, ambiguities found in the Moran model associated with the introduction of more complex processes, such as selection, are avoided.

  15. Models of Genetic Drift as Limiting Forms of the Lotka-Volterra Competition Model

    NASA Astrophysics Data System (ADS)

    Constable, George W. A.; McKane, Alan J.

    2015-01-01

    The relationship between the Moran model and stochastic Lotka-Volterra competition (SLVC) model is explored via time scale separation arguments. For neutral systems the two are found to be equivalent at long times. For systems with selective pressure, their behavior differs. It is argued that the SLVC is preferable to the Moran model since in the SLVC population size is regulated by competition, rather than arbitrarily fixed as in the Moran model. As a consequence, ambiguities found in the Moran model associated with the introduction of more complex processes, such as selection, are avoided.

  16. Models of genetic drift as limiting forms of the Lotka-Volterra competition model.

    PubMed

    Constable, George W A; McKane, Alan J

    2015-01-23

    The relationship between the Moran model and stochastic Lotka-Volterra competition (SLVC) model is explored via time scale separation arguments. For neutral systems the two are found to be equivalent at long times. For systems with selective pressure, their behavior differs. It is argued that the SLVC is preferable to the Moran model since in the SLVC population size is regulated by competition, rather than arbitrarily fixed as in the Moran model. As a consequence, ambiguities found in the Moran model associated with the introduction of more complex processes, such as selection, are avoided. PMID:25659024

  17. Rapid quantification of adenosine cyclic 3',5'-monophosphate by competitive enzyme-linked immunosorbent assay.

    PubMed

    Hsieh, M S; Jap, T S; Chiang, H

    1993-01-01

    A reliable and rapid enzyme-linked immunosorbent assay (ELISA) for cyclic AMP determination is described. Succinyl cyclic AMP, coupled to human albumin, was injected into rabbit to elicit antibodies to cyclic nucleotide hapten. Succinyl cyclic nucleotide to human albumin as immunogen or the cyclic AMP to porcine thyroglobulin as coating antigen was conjugated by a carbodiimide coupling procedure. The latter conjugate, captured to microplate with coating buffer and blocked with 0.8% gelatin for 30 minutes, was bound to antibody in inverse proportion to free cyclic AMP in a sample or standard. Bound antibody was then quantified with horseradish peroxidase-labelled goat antirabbit immunoglobulin and ABTS (2, 2'-Azinobis (3-ethylbenzthiazolinesulfonic Acid). Our results showed that concentration of both standard and sample cyclic AMP could be measured as low as 2.5 fmol/well (0.05 pmol/ml). The intra- and inter-assay coefficients of variation for samples were 6.0-8.0% and 8.9-9.5%, respectively. In addition, there was no cross-reaction of the antisera with ADP, ATP, 5'-AMP or cyclic GMP. Short period of incubation at room temperature seems as good as long period of incubation at 4 degrees C. The biological study demonstrated a consistency between increase in platelet-cyclic AMP generation after prostaglandin E1 stimulation and its biological effects. Our approach to ELISA is validated by showing agreement in levels, obtained in parallel by ELISA and RIA, of cyclic AMP content in extracts of prostaglandin E1-stimulated platelet cells.

  18. Discriminating facial expressions of emotion and its link with perceiving visual form in Parkinson's disease.

    PubMed

    Marneweck, Michelle; Hammond, Geoff

    2014-11-15

    We investigated the link between the ability to perceive facial expressions of emotion and the ability to perceive visual form in Parkinson's disease (PD). We assessed in individuals with PD and healthy controls the ability to discriminate graded intensities of facial expressions of anger from neutral expressions and the ability to discriminate radial frequency (RF) patterns with modulations in amplitude from a perfect circle. Those with PD were, as a group, impaired relative to controls in discriminating graded intensities of angry from neutral expressions and discriminating modulated amplitudes of RF patterns from perfect circles; these two abilities correlated positively and moderately to highly, even after removing the variance that was shared with disease progression and general cognitive functioning. The results indicate that the impaired ability to perceive visual form is likely to contribute to the impaired ability to perceive facial expressions of emotion in PD, and that both are related to the progression of the disease. PMID:25179875

  19. Form Follows Function: can Tropical Mountain Forest Competition Drive the Growth of Topography?

    NASA Astrophysics Data System (ADS)

    Brocard, G. Y.; Willenbring, J. K.; Scatena, F. N.

    2014-12-01

    Forest succession theory maintains that trees drape existing landscapes as passive niche optimizers. Here, we explore the opposite view - that tree type can control the landscape morphology through canopy and soil structure differences between tree types. Using field observations combined with the analysis of a 1 m-resolution LiDAR DEM and cosmogenic nuclide geochemical techniques, we report links between topographic position, erosion rates, and tree distribution above 600 m in elevation in the pristine, tropical rainforest of the Luquillo Critical Zone Observatory, Puerto Rico. Above 600 m, flat ridges connect a subdued topographic surface and cap a relict landscape composed of 10s-of-meters-thick saprolite derived from a quartz dioritic bedrock. Erosion in the form of concave coves dissects this landscape, exposing the underlying corestones and bedrock and progressively creating a new landscape of greater local relief and higher erosion. To understand the origin of the increase in local relief we measured the respective contributions of ridges and coves to the stream signal by analyzing 10Be in soils and stream sediments. We find that, in the coves, erosion is systematically higher than on the ridges, confirming the increase in landscape dissection. Because the overall forest structure has not been altered by anthropogenic disturbances, the tree type represents a long-term feature of the landscape. We analyzed the distribution of tree associations over the LiDAR topography by classifying high-resolution multispectral images of the forest. Vegetation in the study area is dominated by Palm and Palo Colorado forests. We found an almost systematic association of the Palm forest with the coves and of the Palo Colorado with the ridges. These forest types vary in their potential to prevent or enhance soil erosion. The Palo Colorado generates greater soil coverage and rain interception rates. Therefore, we propose that soils are more vulnerable to erosion under the Palm

  20. Synthesis and characterization of monomolecular DNA G-quadruplexes formed by tetra-end-linked oligonucleotides.

    PubMed

    Oliviero, Giorgia; Amato, Jussara; Borbone, Nicola; Galeone, Aldo; Petraccone, Luigi; Varra, Michela; Piccialli, Gennaro; Mayol, Luciano

    2006-01-01

    Guanine-rich DNA sequences are widely dispersed in the eukaryotic genome and are abundant in regions with relevant biological significance. They can form quadruplex structures stabilized by guanine quartets. These structures differ for number and strand polarity, loop composition, and conformation. We report here the syntheses and the structural studies of a set of interconnected d(TG(4)T) fragments which are tethered, with different orientations, to a tetra-end-linker in an attempt to force the formation of specific four-stranded DNA quadruplex structures. Two synthetic strategies have been used to obtain oligodeoxyribonucleotide (ODN) strands linked with their 3'- or 5'-ends to each of the four arms of the linker. The first approach allowed the synthesis of tetra-end-linked ODN (TEL-ODN) containing the four ODN strands with a parallel orientation, while the latter synthetic pathway led to the synthesis of TEL-ODNs each containing antiparallel ODN pairs. The influence of the linker at 3'- or 5'-ODN, on the quadruplex typology and stability, in the presence of sodium or potassium ions, has been investigated by circular dichroism (CD), CD thermal denaturation, (1)H NMR experiments at variable temperature, and molecular modeling. All synthesized TEL-ODNs formed parallel G-quadruplex structures. Particularly, the TEL-ODN containing all parallel ODN tracts formed very stable parallel G-quadruplex complexes, whereas the TEL-ODNs containing antiparallel ODN pairs led to relatively less stable parallel G-quadruplexes. The molecular modeling data suggested that the above antiparallel TEL-ODNs can adopt parallel G-quadruplex structures thanks to a considerable folding of the tetra-end-linker around the whole quadruplex scaffold.

  1. Gene-Environment Interplay in the Link of Friends' and Nonfriends' Behaviors with Children's Social Reticence in a Competitive Situation

    ERIC Educational Resources Information Center

    Guimond, Fanny-Alexandra; Brendgen, Mara; Vitaro, Frank; Forget-Dubois, Nadine; Dionne, Ginette; Tremblay, Richard E.; Boivin, Michel

    2014-01-01

    This study used a genetically informed design to assess the effects of friends' and nonfriends' reticent and dominant behaviors on children's observed social reticence in a competitive situation. Potential gene-environment correlations (rGE) and gene-environment interactions (GxE) in the link between (a) friends' and…

  2. Monoclonal antibody-based competitive enzyme-linked immunosorbent assay to detect antibodies to O:4 Salmonella in the sera of livestock and poultry.

    PubMed

    Aribam, Swarmistha Devi; Ogawa, Yohsuke; Matsui, Hidenori; Hirota, Jiro; Okamura, Masashi; Akiba, Masato; Shimoji, Yoshihiro; Eguchi, Masahiro

    2015-01-01

    Serotyping is an important element for surveillance of Salmonella. In this study, an anti-O:4 Salmonella monoclonal antibody-based competitive enzyme-linked immunosorbent assay that could identify Salmonella infection in cow, pig, horse, and chicken was developed. This detection system can therefore be useful for a wide range of animals and for humans.

  3. Detection of Francisella tularensis-specific antibodies in patients with tularemia by a novel competitive enzyme-linked immunosorbent assay.

    PubMed

    Sharma, Neekun; Hotta, Akitoyo; Yamamoto, Yoshie; Fujita, Osamu; Uda, Akihiko; Morikawa, Shigeru; Yamada, Akio; Tanabayashi, Kiyoshi

    2013-01-01

    A novel competitive enzyme-linked immunosorbent assay (cELISA) was developed and evaluated for detection of antibodies against Francisella tularensis in humans. The assay is based on the ability of serum antibodies to inhibit the binding of monoclonal antibodies (MAbs) directed against F. tularensis lipopolysaccharide antigens. The assay was evaluated using serum samples of tularemia patients, inactivated F. tularensis-immunized rabbits, and F. tularensis-infected mice. Antibodies against F. tularensis were successfully detected in serum samples of tularemia patients as well as the immunized and infected animals. The cELISA method was compared to indirect ELISA (iELISA) and the commonly used microagglutination test (MA) using serum samples of 19 tularemia patients and 50 healthy individuals. The sensitivity and specificity of cELISA were 93.9 and 96.1%, respectively, in comparison to the iELISA. MA was less sensitive than cELISA with a sensitivity and specificity of only 81.8 and 98.0%, respectively. A high degree of correlation (R(2) = 0.8226) was observed between cELISA and iELISA results. The novel cELISA developed in this study appears to be highly sensitive and specific for serodiagnosis of human tularemia. The potential of the MAb-based cELISA to be used in both human and animal samples emphasizes its usefulness for serological survey of tularemia among multiple animal species. PMID:23114700

  4. Detection of Francisella tularensis-Specific Antibodies in Patients with Tularemia by a Novel Competitive Enzyme-Linked Immunosorbent Assay

    PubMed Central

    Sharma, Neekun; Hotta, Akitoyo; Yamamoto, Yoshie; Fujita, Osamu; Uda, Akihiko; Morikawa, Shigeru; Yamada, Akio

    2013-01-01

    A novel competitive enzyme-linked immunosorbent assay (cELISA) was developed and evaluated for detection of antibodies against Francisella tularensis in humans. The assay is based on the ability of serum antibodies to inhibit the binding of monoclonal antibodies (MAbs) directed against F. tularensis lipopolysaccharide antigens. The assay was evaluated using serum samples of tularemia patients, inactivated F. tularensis-immunized rabbits, and F. tularensis-infected mice. Antibodies against F. tularensis were successfully detected in serum samples of tularemia patients as well as the immunized and infected animals. The cELISA method was compared to indirect ELISA (iELISA) and the commonly used microagglutination test (MA) using serum samples of 19 tularemia patients and 50 healthy individuals. The sensitivity and specificity of cELISA were 93.9 and 96.1%, respectively, in comparison to the iELISA. MA was less sensitive than cELISA with a sensitivity and specificity of only 81.8 and 98.0%, respectively. A high degree of correlation (R2 = 0.8226) was observed between cELISA and iELISA results. The novel cELISA developed in this study appears to be highly sensitive and specific for serodiagnosis of human tularemia. The potential of the MAb-based cELISA to be used in both human and animal samples emphasizes its usefulness for serological survey of tularemia among multiple animal species. PMID:23114700

  5. A highly rapid and simple competitive enzyme-linked immunosorbent assay for monitoring paralytic shellfish poisoning toxins in shellfish.

    PubMed

    Kawatsu, Kentaro; Kanki, Masashi; Harada, Tetsuya; Kumeda, Yuko

    2014-11-01

    Using a streptavidin-coated well plate, a biotin-labelled anti-gonyautoxin 2/3 monoclonal antibody GT-13A, and a decarbamoyl saxitoxin-peroxidase conjugate, a direct competitive enzyme-linked immunosorbent assay (PSP-ELISA) was developed for monitoring paralytic shellfish poisoning (PSP) toxins in shellfish. This assay is simple to perform and can be completed in approximately 20 min. The PSP-ELISA was compared to the mouse bioassay (MBA) for the detection of PSP toxins in shellfish samples (n=83) collected from the coast of Osaka Prefecture, Japan. When positive and negative results were indicated based on the regulatory limit for PSP toxins (4 mouse unit(MU)/g of shellfish meat), the PSP-ELISA results showed a sensitivity of 100% (25 of 25) and a specificity of 89.7% (52 of 58 samples) compared to the MBA results. These results suggest that the PSP-ELISA could be used as a rapid and simple screening method prior to the MBA.

  6. Detection of Francisella tularensis-specific antibodies in patients with tularemia by a novel competitive enzyme-linked immunosorbent assay.

    PubMed

    Sharma, Neekun; Hotta, Akitoyo; Yamamoto, Yoshie; Fujita, Osamu; Uda, Akihiko; Morikawa, Shigeru; Yamada, Akio; Tanabayashi, Kiyoshi

    2013-01-01

    A novel competitive enzyme-linked immunosorbent assay (cELISA) was developed and evaluated for detection of antibodies against Francisella tularensis in humans. The assay is based on the ability of serum antibodies to inhibit the binding of monoclonal antibodies (MAbs) directed against F. tularensis lipopolysaccharide antigens. The assay was evaluated using serum samples of tularemia patients, inactivated F. tularensis-immunized rabbits, and F. tularensis-infected mice. Antibodies against F. tularensis were successfully detected in serum samples of tularemia patients as well as the immunized and infected animals. The cELISA method was compared to indirect ELISA (iELISA) and the commonly used microagglutination test (MA) using serum samples of 19 tularemia patients and 50 healthy individuals. The sensitivity and specificity of cELISA were 93.9 and 96.1%, respectively, in comparison to the iELISA. MA was less sensitive than cELISA with a sensitivity and specificity of only 81.8 and 98.0%, respectively. A high degree of correlation (R(2) = 0.8226) was observed between cELISA and iELISA results. The novel cELISA developed in this study appears to be highly sensitive and specific for serodiagnosis of human tularemia. The potential of the MAb-based cELISA to be used in both human and animal samples emphasizes its usefulness for serological survey of tularemia among multiple animal species.

  7. Hapten synthesis and development of a competitive indirect enzyme-linked immunosorbent assay for acrylamide in food samples.

    PubMed

    Wu, Jing; Shen, Yu-Dong; Lei, Hong-Tao; Sun, Yuan-Ming; Yang, Jin-Yi; Xiao, Zhi-Li; Wang, Hong; Xu, Zhen-Lin

    2014-07-23

    The high level of acrylamide in widely consumed processed foods poses a potentially significant risk to human health, which has led to an increasing demand for rapid, simple, and selective analytical methods. In the present work, several haptens for acrylamide were designed in an attempt to prepare antibodies with acrylamide affinity, but they failed their purpose. However, a polyclonal antibody was produced against 4-mercaptophenylacetic acid (4-MPA)-derivatized acrylamide, which showed high binding affinity to the derivative. As acrylamide easily reacted with 4-MPA at high derivation yield, a competitive indirect enzyme-linked immunosorbent assay (ciELISA) for acrylamide via a preanalysis derivatization was developed. The derivatization and ELISA conditions were fully optimized to produce a method for acrylamide assay that exhibited an IC50 of 2.86 μg/kg, limit of detection at 0.036 μg/kg, and linear range of 0.25-24.15 μg/kg. The results of preanalysis recovery tests of acrylamide-spiked food samples and screening of blind food samples by both ciELISA and HPLC-MS/MS indicated the proposed ciELISA's good accuracy and reliability. This method was thus deemed suitable for routine acrylamide screening in food samples at low cost.

  8. A new form of X-linked mental retardation with growth retardation, deafness, and microgenitalism.

    PubMed Central

    Juberg, R C; Marsidi, I

    1980-01-01

    The proband and two maternal uncles were similarly affected by a unique constellation of mental retardation and physical abnormalities. There were severe retardation, growth less than the third percentile, and significantly delayed bone age. They manifested deafness, a flat nasal bridge, several ocular abnormalities, and a rudimentary scrotum with cryptorchidism, and one had a small penis. The proband also had onychodystrophy of his fingers and toes. Their birth weights and lengths were less than expected. No chromosomal or biochemical abnormality was detected. Both uncles died, but the proband is healthy at 4 years. Their phenotype is distinguished from other forms of X-linked mental retardation and appears to be a new syndrome. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:6107045

  9. Form-based priming in spoken word recognition: the roles of competition and bias.

    PubMed

    Goldinger, S D; Luce, P A; Pisoni, D B; Marcario, J K

    1992-11-01

    Phonological priming of spoken words refers to improved recognition of targets preceded by primes that share at least one of their constituent phonemes (e.g., BULL-BEER). Phonetic priming refers to reduced recognition of targets preceded by primes that share no phonemes with targets but are phonetically similar to targets (e.g., BULL-VEER). Five experiments were conducted to investigate the role of bias in phonological priming. Performance was compared across conditions of phonological and phonetic priming under a variety of procedural manipulations. Ss in phonological priming conditions systematically modified their responses on unrelated priming trials in perceptual identification, and they were slower and more errorful on unrelated trials in lexical decision than were Ss in phonetic priming conditions. Phonetic and phonological priming effects display different time courses and also different interactions with changes in proportion of related priming trials. Phonological priming involves bias; phonetic priming appears to reflect basic properties of activation and competition in spoken word recognition.

  10. X-Linked Recessive form of Nephrogenic Diabetes Insipidus in a 7-Year-Old Boy.

    PubMed

    Janchevska, A; Tasic, V; Gucev, Z; Krstevska-Konstantinova, M; Cheong, H I

    2014-12-01

    Nephrogenic diabetes insipidus (NDI) is caused by the inability of renal collecting duct cells to respond to arginine vasopressin (AVP)/antidiuretic hormone (ADH). We present the case of a 7-year-old boy with a history of excretion of large amounts of dilute urine and polydipsia since infancy. The boy had several vomiting episodes with mild dehydration during the first 3 years of life. There was no evidence of headaches, dizziness or visual problems. He drinks between 2 and 3 L/day and has 24-hour diuresis of 2 liters, now. He has prepubertal appearance with appropriate weight [+0.85 standard deviation score (SDS)] and height (+0.15 SDS) for his age. His intelligence was also normal. The water deprivation test showed low urine osmolality after 8 hours of dehydration. After desmopressin administration, urine osmolality remained low. Serum osmolality was in the normal range for sex and age before and after desmopressin administration. This indicated a nephrogenic form of diabetes insipidus. Molecular analyses revealed a P286L [p.Pro(CCC)286Leu(CTC)] mutation in the AVPR2 gene, that was inherited from his mother. This patient is the first case with genetically confirmed X-linked inherited form of NDI in the Republic of Macedonia. Molecular analysis confirmed the clinical diagnosis and enabled genetic advice for this family. PMID:25937802

  11. X-Linked Recessive form of Nephrogenic Diabetes Insipidus in a 7-Year-Old Boy.

    PubMed

    Janchevska, A; Tasic, V; Gucev, Z; Krstevska-Konstantinova, M; Cheong, H I

    2014-12-01

    Nephrogenic diabetes insipidus (NDI) is caused by the inability of renal collecting duct cells to respond to arginine vasopressin (AVP)/antidiuretic hormone (ADH). We present the case of a 7-year-old boy with a history of excretion of large amounts of dilute urine and polydipsia since infancy. The boy had several vomiting episodes with mild dehydration during the first 3 years of life. There was no evidence of headaches, dizziness or visual problems. He drinks between 2 and 3 L/day and has 24-hour diuresis of 2 liters, now. He has prepubertal appearance with appropriate weight [+0.85 standard deviation score (SDS)] and height (+0.15 SDS) for his age. His intelligence was also normal. The water deprivation test showed low urine osmolality after 8 hours of dehydration. After desmopressin administration, urine osmolality remained low. Serum osmolality was in the normal range for sex and age before and after desmopressin administration. This indicated a nephrogenic form of diabetes insipidus. Molecular analyses revealed a P286L [p.Pro(CCC)286Leu(CTC)] mutation in the AVPR2 gene, that was inherited from his mother. This patient is the first case with genetically confirmed X-linked inherited form of NDI in the Republic of Macedonia. Molecular analysis confirmed the clinical diagnosis and enabled genetic advice for this family.

  12. X-Linked Recessive form of Nephrogenic Diabetes Insipidus in a 7-Year-Old Boy

    PubMed Central

    Janchevska, A; Tasic; Gucev, Z; Krstevska-Konstantinova, M; Cheong, HI

    2014-01-01

    Nephrogenic diabetes insipidus (NDI) is caused by the inability of renal collecting duct cells to respond to arginine vasopressin (AVP)/antidiuretic hormone (ADH). We present the case of a 7-year-old boy with a history of excretion of large amounts of dilute urine and polydipsia since infancy. The boy had several vomiting episodes with mild dehydration during the first 3 years of life. There was no evidence of headaches, dizziness or visual problems. He drinks between 2 and 3 L/day and has 24-hour diuresis of 2 liters, now. He has prepubertal appearance with appropriate weight [+0.85 standard deviation score (SDS)] and height (+0.15 SDS) for his age. His intelligence was also normal. The water deprivation test showed low urine osmolality after 8 hours of dehydration. After desmopressin administration, urine osmolality remained low. Serum osmolality was in the normal range for sex and age before and after desmopressin administration. This indicated a nephrogenic form of diabetes insipidus. Molecular analyses revealed a P286L [p.Pro(CCC)286Leu(CTC)] mutation in the AVPR2 gene, that was inherited from his mother. This patient is the first case with genetically confirmed X-linked inherited form of NDI in the Republic of Macedonia. Molecular analysis confirmed the clinical diagnosis and enabled genetic advice for this family. PMID:25937802

  13. A repeat protein links Rubisco to form the eukaryotic carbon-concentrating organelle.

    PubMed

    Mackinder, Luke C M; Meyer, Moritz T; Mettler-Altmann, Tabea; Chen, Vivian K; Mitchell, Madeline C; Caspari, Oliver; Freeman Rosenzweig, Elizabeth S; Pallesen, Leif; Reeves, Gregory; Itakura, Alan; Roth, Robyn; Sommer, Frederik; Geimer, Stefan; Mühlhaus, Timo; Schroda, Michael; Goodenough, Ursula; Stitt, Mark; Griffiths, Howard; Jonikas, Martin C

    2016-05-24

    Biological carbon fixation is a key step in the global carbon cycle that regulates the atmosphere's composition while producing the food we eat and the fuels we burn. Approximately one-third of global carbon fixation occurs in an overlooked algal organelle called the pyrenoid. The pyrenoid contains the CO2-fixing enzyme Rubisco and enhances carbon fixation by supplying Rubisco with a high concentration of CO2 Since the discovery of the pyrenoid more that 130 y ago, the molecular structure and biogenesis of this ecologically fundamental organelle have remained enigmatic. Here we use the model green alga Chlamydomonas reinhardtii to discover that a low-complexity repeat protein, Essential Pyrenoid Component 1 (EPYC1), links Rubisco to form the pyrenoid. We find that EPYC1 is of comparable abundance to Rubisco and colocalizes with Rubisco throughout the pyrenoid. We show that EPYC1 is essential for normal pyrenoid size, number, morphology, Rubisco content, and efficient carbon fixation at low CO2 We explain the central role of EPYC1 in pyrenoid biogenesis by the finding that EPYC1 binds Rubisco to form the pyrenoid matrix. We propose two models in which EPYC1's four repeats could produce the observed lattice arrangement of Rubisco in the Chlamydomonas pyrenoid. Our results suggest a surprisingly simple molecular mechanism for how Rubisco can be packaged to form the pyrenoid matrix, potentially explaining how Rubisco packaging into a pyrenoid could have evolved across a broad range of photosynthetic eukaryotes through convergent evolution. In addition, our findings represent a key step toward engineering a pyrenoid into crops to enhance their carbon fixation efficiency. PMID:27166422

  14. A repeat protein links Rubisco to form the eukaryotic carbon-concentrating organelle

    PubMed Central

    Mackinder, Luke C. M.; Meyer, Moritz T.; Mettler-Altmann, Tabea; Chen, Vivian K.; Mitchell, Madeline C.; Caspari, Oliver; Freeman Rosenzweig, Elizabeth S.; Pallesen, Leif; Reeves, Gregory; Itakura, Alan; Roth, Robyn; Sommer, Frederik; Geimer, Stefan; Mühlhaus, Timo; Schroda, Michael; Goodenough, Ursula; Stitt, Mark; Griffiths, Howard; Jonikas, Martin C.

    2016-01-01

    Biological carbon fixation is a key step in the global carbon cycle that regulates the atmosphere's composition while producing the food we eat and the fuels we burn. Approximately one-third of global carbon fixation occurs in an overlooked algal organelle called the pyrenoid. The pyrenoid contains the CO2-fixing enzyme Rubisco and enhances carbon fixation by supplying Rubisco with a high concentration of CO2. Since the discovery of the pyrenoid more that 130 y ago, the molecular structure and biogenesis of this ecologically fundamental organelle have remained enigmatic. Here we use the model green alga Chlamydomonas reinhardtii to discover that a low-complexity repeat protein, Essential Pyrenoid Component 1 (EPYC1), links Rubisco to form the pyrenoid. We find that EPYC1 is of comparable abundance to Rubisco and colocalizes with Rubisco throughout the pyrenoid. We show that EPYC1 is essential for normal pyrenoid size, number, morphology, Rubisco content, and efficient carbon fixation at low CO2. We explain the central role of EPYC1 in pyrenoid biogenesis by the finding that EPYC1 binds Rubisco to form the pyrenoid matrix. We propose two models in which EPYC1’s four repeats could produce the observed lattice arrangement of Rubisco in the Chlamydomonas pyrenoid. Our results suggest a surprisingly simple molecular mechanism for how Rubisco can be packaged to form the pyrenoid matrix, potentially explaining how Rubisco packaging into a pyrenoid could have evolved across a broad range of photosynthetic eukaryotes through convergent evolution. In addition, our findings represent a key step toward engineering a pyrenoid into crops to enhance their carbon fixation efficiency. PMID:27166422

  15. A direct competitive enzyme-linked immunosorbent assay for rapid detection of anilofos residues in agricultural products and environmental samples.

    PubMed

    Zhang, Yan; Gao, Ai H; Liu, Bing; Sheng, Wei; Tan, Chao; Yuan, Meng; Wang, Shuo

    2013-01-01

    A direct competitive enzyme-linked immunosorbent assay (dc-ELISA) was developed to measure anilofos levels in agricultural and environmental samples. The ELISA was developed using rabbit polyclonal antibodies against a hapten-protein conjugate of anilofos-bovine serum albumin. The limit of detection was 0.1 μg L(-1), and there was no cross-reactivity with other related pesticides or structurally similar compounds. The matrix effects of rice (aromatic rice, white rice, brown rice), corn, barley, wheat and soil were measured and removed by extraction and dilution with phosphate buffered saline with 0.05% Tween-20. For water samples (tap water and river water), the matrix effects were also removed by dilution with phosphate buffered saline with Tween-20. The detection limits for anilofos in authentic samples (aromatic rice, white rice, brown rice, corn, barley, wheat, soil, tap water and river water) were 2, 2, 2, 3, 2, 2, and 2 μg kg(-1), and 0.5 and 1 μg L(-1), respectively . The anilofos recovery ranged from 81.0-116.0% with a coefficient of variation of 1.7-9.0%. The method was validated using GC, and the results showed good correlation with the dc-ELISA data (r(2) = 0.9795). Forty-two cereal samples were randomly collected from different supermarkets and analyzed using the developed dc-ELISA. No anilofos was found in these products. The developed immunoassay is suitable for rapid quantitation of anilofos residues. PMID:23030434

  16. Validation and Field Evaluation of a Competitive Enzyme-Linked Immunosorbent Assay for Diagnosis of Babesia bovis Infections in Argentina

    PubMed Central

    Dominguez, Mariana; Echaide, Ignacio; de Echaide, Susana Torioni; Wilkowsky, Silvina; Zabal, Osvaldo; Mosqueda, Juan J.; Schnittger, Leonhard

    2012-01-01

    Infections by Babesia bovis limit cattle production and cause important economic losses in tropical and subtropical areas around the world. Monitoring of calf sera can be used to detect unprotected cattle herds and to decide on strategic control measures, as well as for epidemiological studies. Merozoite surface antigen 2c (MSA-2c) is an immunodominant surface protein expressed in B. bovis merozoites and sporozoites and contains B-cell epitopes that are conserved among geographic isolates. A monoclonal antibody against recombinant MSA-2c (rMSA-2c) was previously shown to inhibit the binding of anti-B. bovis antibodies to a parasite B-cell epitope in a competitive enzyme-linked immunosorbent assay (cELISA) format. In the work at hand, the parameters of this cELISA were reevaluated and adjusted when necessary, and a cutoff value was determined by receiver operator characteristic (ROC) curve analysis of a total of 357 bovine sera of known reactivity, as assessed by indirect immunofluorescence assay (IFAT). The established rMSA-2c cELISA demonstrated a specificity of 98% and a sensitivity of 96.2%. An additional set of 303 field bovine sera from regions where ticks are endemic and tick-free regions of Argentina was tested by both rMSA-2c cELISA and IFAT, and the results were shown to be in very good agreement (kappa index, 0.8325). The performance shown by rMSA-2c cELISA in the detection of B. bovis-specific antibodies and its suitability for standardization and large-scale production, as well as the possibility of its application in most veterinary diagnostic laboratories, make the assay a powerful tool for the surveillance of herd immunity as a strategic measure for the control of bovine babesiosis. PMID:22492742

  17. Magnetic-nanobead-based competitive enzyme-linked aptamer assay for the analysis of oxytetracycline in food.

    PubMed

    Lu, Chunxia; Tang, Zonggui; Liu, Changbin; Kang, Lichao; Sun, Fengxia

    2015-05-01

    This study presents a novel analytical method for the detection of oxytetracycline (OTC) in complex food matrices based on a direct competitive enzyme-linked aptamer assay and magnetic separation technology. In this protocol, free OTC competed with horseradish peroxidase labeled OTC (OTC-HRP) for binding to the OTC aptamer immobilized on magnetic beads. The parameters that can affect the response, such as avidin concentration, aptamer concentration, OTC-HRP concentration, incubation temperature, incubation time, blocking agent, and binding buffer, were optimized. Under the optimal conditions, the linear range for the OTC concentration detection is 0.5-100 ng mL(-1), with a concentration of OTC needed to obtain 50 % of the maximum signal of 14.47 ng mL(-1). The limit of detection and the limit of quantitation were 0.88 and 3.40 ng mL(-1), respectively. There was no obvious cross-reactivity with most of the tetracycline pesticides. The recovery rates ranged from 71.0 to 91.2 % for the food samples, including chicken, milk, and honey, and the relative standard deviation was less than 15.0 %. The proposed method was applied to measure OTC in real samples, and was validated using high-performance liquid chromatography. This method has the advantages of magnetic separation and the concentration effect of magnetic nanoparticles, the specificity of the aptamer, and the high-throughput of microtiter plates; it offers a promising approach for the screening of OTC because it is simple, rapid, highly sensitive, and has low cost.

  18. Magnetic-nanobead-based competitive enzyme-linked aptamer assay for the analysis of oxytetracycline in food.

    PubMed

    Lu, Chunxia; Tang, Zonggui; Liu, Changbin; Kang, Lichao; Sun, Fengxia

    2015-05-01

    This study presents a novel analytical method for the detection of oxytetracycline (OTC) in complex food matrices based on a direct competitive enzyme-linked aptamer assay and magnetic separation technology. In this protocol, free OTC competed with horseradish peroxidase labeled OTC (OTC-HRP) for binding to the OTC aptamer immobilized on magnetic beads. The parameters that can affect the response, such as avidin concentration, aptamer concentration, OTC-HRP concentration, incubation temperature, incubation time, blocking agent, and binding buffer, were optimized. Under the optimal conditions, the linear range for the OTC concentration detection is 0.5-100 ng mL(-1), with a concentration of OTC needed to obtain 50 % of the maximum signal of 14.47 ng mL(-1). The limit of detection and the limit of quantitation were 0.88 and 3.40 ng mL(-1), respectively. There was no obvious cross-reactivity with most of the tetracycline pesticides. The recovery rates ranged from 71.0 to 91.2 % for the food samples, including chicken, milk, and honey, and the relative standard deviation was less than 15.0 %. The proposed method was applied to measure OTC in real samples, and was validated using high-performance liquid chromatography. This method has the advantages of magnetic separation and the concentration effect of magnetic nanoparticles, the specificity of the aptamer, and the high-throughput of microtiter plates; it offers a promising approach for the screening of OTC because it is simple, rapid, highly sensitive, and has low cost. PMID:25855149

  19. Serosurveillance for Francisella tularensis Among Wild Animals in Japan Using a Newly Developed Competitive Enzyme-Linked Immunosorbent Assay

    PubMed Central

    Sharma, Neekun; Hotta, Akitoyo; Yamamoto, Yoshie; Uda, Akihiko; Fujita, Osamu; Mizoguchi, Toshio; Shindo, Junji; Park, Chun-Ho; Kudo, Noboru; Hatai, Hitoshi; Oyamada, Toshifumi; Yamada, Akio; Morikawa, Shigeru

    2014-01-01

    Abstract Tularemia, a highly infectious zoonotic disease caused by Francisella tularensis, occurs sporadically in Japan. However, little is known about the prevalence of the disease in wild animals. A total of 632 samples obtained from 150 Japanese black bears, 142 Japanese hares, 120 small rodents, 97 rats, 53 raptors, 26 Japanese monkeys, 21 Japanese raccoon dogs, 20 masked palm civets, and three Japanese red foxes between 2002 and 2010 were investigated for the presence of antibodies to F. tularensis by competitive enzyme-linked immunosorbent assay (cELISA) and the commonly used microagglutination (MA) test. Seropositive cELISA and MA results were obtained in 23 and 18 Japanese black bears, three and two Japanese raccoon dogs, and two and one small rodents, respectively. All MA-positive samples (n=21) were also positive by cELISA. Six of seven samples that were only positive by cELISA were confirmed to be antibody-positive by western blot analysis. These findings suggest that cELISA is a highly sensitive and useful test for serosurveillance of tularemia among various species of wild animals. Because this is the first study to detect F. tularensis–seropositive Japanese raccoon dogs, these could join Japanese black bears as sentinel animals for tularemia in the wild in Japan. Further continuous serosurveillance for F. tularensis in various species of wild animals using appropriate methods such as cELISA is important to assess the risks of human exposure and to improve our understanding of the ecology of F. tularensis in the wild. PMID:24689989

  20. Serosurveillance for Francisella tularensis among wild animals in Japan using a newly developed competitive enzyme-linked immunosorbent assay.

    PubMed

    Sharma, Neekun; Hotta, Akitoyo; Yamamoto, Yoshie; Uda, Akihiko; Fujita, Osamu; Mizoguchi, Toshio; Shindo, Junji; Park, Chun-Ho; Kudo, Noboru; Hatai, Hitoshi; Oyamada, Toshifumi; Yamada, Akio; Morikawa, Shigeru; Tanabayashi, Kiyoshi

    2014-04-01

    Tularemia, a highly infectious zoonotic disease caused by Francisella tularensis, occurs sporadically in Japan. However, little is known about the prevalence of the disease in wild animals. A total of 632 samples obtained from 150 Japanese black bears, 142 Japanese hares, 120 small rodents, 97 rats, 53 raptors, 26 Japanese monkeys, 21 Japanese raccoon dogs, 20 masked palm civets, and three Japanese red foxes between 2002 and 2010 were investigated for the presence of antibodies to F. tularensis by competitive enzyme-linked immunosorbent assay (cELISA) and the commonly used microagglutination (MA) test. Seropositive cELISA and MA results were obtained in 23 and 18 Japanese black bears, three and two Japanese raccoon dogs, and two and one small rodents, respectively. All MA-positive samples (n=21) were also positive by cELISA. Six of seven samples that were only positive by cELISA were confirmed to be antibody-positive by western blot analysis. These findings suggest that cELISA is a highly sensitive and useful test for serosurveillance of tularemia among various species of wild animals. Because this is the first study to detect F. tularensis-seropositive Japanese raccoon dogs, these could join Japanese black bears as sentinel animals for tularemia in the wild in Japan. Further continuous serosurveillance for F. tularensis in various species of wild animals using appropriate methods such as cELISA is important to assess the risks of human exposure and to improve our understanding of the ecology of F. tularensis in the wild. PMID:24689989

  1. Cross-Linking Mast Cell Specific Gangliosides Stimulates the Release of Newly Formed Lipid Mediators and Newly Synthesized Cytokines.

    PubMed

    Filho, Edismauro Garcia Freitas; da Silva, Elaine Zayas Marcelino; Zanotto, Camila Ziliotto; Oliver, Constance; Jamur, Maria Célia

    2016-01-01

    Mast cells are immunoregulatory cells that participate in inflammatory processes. Cross-linking mast cell specific GD1b derived gangliosides by mAbAA4 results in partial activation of mast cells without the release of preformed mediators. The present study examines the release of newly formed and newly synthesized mediators following ganglioside cross-linking. Cross-linking the gangliosides with mAbAA4 released the newly formed lipid mediators, prostaglandins D2 and E2, without release of leukotrienes B4 and C4. The effect of cross-linking these gangliosides on the activation of enzymes in the arachidonate cascade was then investigated. Ganglioside cross-linking resulted in phosphorylation of cytosolic phospholipase A2 and increased expression of cyclooxygenase-2. Translocation of 5-lipoxygenase from the cytosol to the nucleus was not induced by ganglioside cross-linking. Cross-linking of GD1b derived gangliosides also resulted in the release of the newly synthesized mediators, interleukin-4, interleukin-6, and TNF-α. The effect of cross-linking the gangliosides on the MAP kinase pathway was then investigated. Cross-linking the gangliosides induced the phosphorylation of ERK1/2, JNK1/2, and p38 as well as activating both NFκB and NFAT in a Syk-dependent manner. Therefore, cross-linking the mast cell specific GD1b derived gangliosides results in the activation of signaling pathways that culminate with the release of newly formed and newly synthesized mediators. PMID:27578923

  2. Cross-Linking Mast Cell Specific Gangliosides Stimulates the Release of Newly Formed Lipid Mediators and Newly Synthesized Cytokines

    PubMed Central

    Zanotto, Camila Ziliotto

    2016-01-01

    Mast cells are immunoregulatory cells that participate in inflammatory processes. Cross-linking mast cell specific GD1b derived gangliosides by mAbAA4 results in partial activation of mast cells without the release of preformed mediators. The present study examines the release of newly formed and newly synthesized mediators following ganglioside cross-linking. Cross-linking the gangliosides with mAbAA4 released the newly formed lipid mediators, prostaglandins D2 and E2, without release of leukotrienes B4 and C4. The effect of cross-linking these gangliosides on the activation of enzymes in the arachidonate cascade was then investigated. Ganglioside cross-linking resulted in phosphorylation of cytosolic phospholipase A2 and increased expression of cyclooxygenase-2. Translocation of 5-lipoxygenase from the cytosol to the nucleus was not induced by ganglioside cross-linking. Cross-linking of GD1b derived gangliosides also resulted in the release of the newly synthesized mediators, interleukin-4, interleukin-6, and TNF-α. The effect of cross-linking the gangliosides on the MAP kinase pathway was then investigated. Cross-linking the gangliosides induced the phosphorylation of ERK1/2, JNK1/2, and p38 as well as activating both NFκB and NFAT in a Syk-dependent manner. Therefore, cross-linking the mast cell specific GD1b derived gangliosides results in the activation of signaling pathways that culminate with the release of newly formed and newly synthesized mediators. PMID:27578923

  3. Use of hydrazine to release in intact and unreduced form both N- and O-linked oligosaccharides from glycoproteins.

    PubMed

    Patel, T; Bruce, J; Merry, A; Bigge, C; Wormald, M; Jaques, A; Parekh, R

    1993-01-19

    The use of hydrazine to release unreduced N- and O-linked oligosaccharides from glycoproteins has been investigated using several "standard" glycoproteins of previously defined glycosylation. It is shown that hydrazinolysis can be used to release intact N- and O-linked oligosaccharides in an unreduced form. The release of O-linked oligosaccharides occurs with a lower temperature dependence than the release of N-linked oligosaccharides, and the kinetic parameters governing release of oligosaccharides from these standard glycoproteins have been determined. These parameters allow a definition of reaction conditions under which anhydrous hydrazinolysis can be used to selectively release O-linked oligosaccharides (60 degrees C, 5 h) or release both N- and O-linked oligosaccharides (95 degrees C, 4 h) in high yield (> 85%) from all glycoproteins investigated (n = 11). Under these reaction conditions, the recovered N- and O-linked oligosaccharides are structurally intact (as judged by 600-MHz 1H-NMR, laser-desorption mass spectrometry, HPAEC-PAD, gel filtration, and glycosidase digestion), with the possible exception of certain N- and O-acyl substituents of sialic acid. This use of mild hydrazinolysis therefore allows both the simultaneous and sequential chemical release from glycoproteins of O- and N-linked oligosaccharides in their intact unreduced form.

  4. Semiquantitative determination of ergot alkaloids in seed, straw, and digesta samples using a competitive enzyme-linked immunosorbent assay.

    PubMed

    Schnitzius, J M; Hill, N S; Thompson, C S; Craig, A M

    2001-05-01

    Ergot alkaloids present in endophyte-infected (E+) tall fescue cause fescue toxicosis and other toxic effects in livestock that consume infected plant tissue, leading to significant financial losses in livestock production each year. The predominant method currently in use for quantifying ergot alkaloid content in plant tissue is through high-performance liquid chromatography (HPLC), which quantifies the amount of ergovaline, one of many ergot alkaloids in E+ plant tissue. The enzyme-linked immunosorbent assay (ELISA) method used in this study detects quantities of nonspecific ergot alkaloids and therefore accounts for greater amounts of the total ergot alkaloid content in E+ tissue than does HPLC. The ELISA can also be used to more expediently analyze a larger number of forage samples without sophisticated and costly analytical equipment and therefore could be more desirable in a diagnostic setting. The purpose of this study was to evaluate the between-day and within-run variability of the ELISA and to determine the binding efficiency of 6 ergot alkaloids to the 15F3.E5 antibody used in the competitive ELISA to ascertain its feasibility as a quick analysis tool for ergot alkaloids. Straw samples had an average coefficient of variation (CV) for concentration of 10.2% within runs and 18.4% between runs, and the seed samples had an average CV for concentration of 13.3% within runs and 24.5% between runs. The grass tissue-based lysergic acid standard curve calculated from the ELISA had an average r2 of 0.99, with a CV of 2.1%. Ergocryptine, ergocristine, ergocornine, and ergotamine tartrate did not bind strongly to the 15F3.E5 antibody because of the presence of large side groups on these molecules, which block their binding to the antibody, whereas ergonovine and ergonovine maleate were bound much more efficiently because of their structural similarity to lysergic acid. Clarified rumen fluid was tested as an additional matrix for use in the ergot alkaloid competitive

  5. The Formamidopyrimidines: Purine Lesions Formed in Competition With 8-Oxopurines From Oxidative Stress

    PubMed Central

    Greenberg, Marc M.

    2011-01-01

    Conspectus DNA is constantly exposed to agents that induce structural damage, from sources both internal and external to an organism. Endogenous species, such as oxidizing chemicals, and exogenous agents, such as ultraviolet rays in sunlight, together produce more than 70 distinct chemical modifications of native nucleotides. Of these, about 15 of the lesions have been detected in cellular DNA. This kind of structural DNA damage can be cytotoxic, carcinogenic, or both, and is being linked to an increasingly lengthy list of diseases. The formamidopyrimidine (Fapy) lesions are a family of DNA lesions that result after purines undergo oxidative stress. The Fapy lesions are produced in yields comparable to the 8-oxopurines, which, owing in part to a perception of mutagenicity in some quarters, have been subjected to intense research scrutiny. But despite the comparable abundance of the formamidopyrimidines and the 8-oxopurines, until recently very little was known about the effects of Fapy lesions on biochemical processes involving DNA or on the structure and stability of the genomic material. In this Account, we discuss the detection of Fapy lesions in DNA and the mechanism proposed for their formation. We also describe methods for the chemical synthesis of oligonucleotides containing Fapy•dA or Fapy•dG and the outcomes of chemical and biochemical studies utilizing these compounds. These experiments reveal that the formamidopyrimidines decrease the fidelity of polymerases and are substrates for DNA repair enzymes. The mutation frequency of Fapy•dG in mammals is even greater than that of 8-oxodGuo (8-oxo-7,8-dihydro-2′-deoxyguanosine, one of the 8-oxopurines), suggesting that this lesion could be a useful biomarker and biologically significant. Despite clear similarities, the formamidopyrimidines have lived in the shadow of the corresponding 8-oxopurine lesions. But the recent development of methods for synthesizing oligonucleotides containing Fapy•dA or

  6. Addressing the Struggle to Link Form and Understanding in Fractions Instruction

    ERIC Educational Resources Information Center

    Osana, Helena P.; Pitsolantis, Nicole

    2013-01-01

    Background: Although making explicit links between procedures and concepts during instruction in mathematics is important, it is still unclear the precise moments during instruction when such links are best made. Aims: The objective was to test the effectiveness of a 3-week classroom intervention on the fractions knowledge of grade 5/6 students.…

  7. Competition between surface adsorption and folding of fibril-forming polypeptides

    NASA Astrophysics Data System (ADS)

    Ni, Ran; Kleijn, J. Mieke; Abeln, Sanne; Cohen Stuart, Martien A.; Bolhuis, Peter G.

    2015-02-01

    Self-assembly of polypeptides into fibrillar structures can be initiated by planar surfaces that interact favorably with certain residues. Using a coarse-grained model, we systematically studied the folding and adsorption behavior of a β -roll forming polypeptide. We find that there are two different folding pathways depending on the temperature: (i) at low temperature, the polypeptide folds in solution into a β -roll before adsorbing onto the attractive surface; (ii) at higher temperature, the polypeptide first adsorbs in a disordered state and folds while on the surface. The folding temperature increases with increasing attraction as the folded β -roll is stabilized by the surface. Surprisingly, further increasing the attraction lowers the folding temperature again, as strong attraction also stabilizes the adsorbed disordered state, which competes with folding of the polypeptide. Our results suggest that to enhance the folding, one should use a weakly attractive surface. They also explain the recent experimental observation of the nonmonotonic effect of charge on the fibril formation on an oppositely charged surface [C. Charbonneau et al., ACS Nano 8, 2328 (2014), 10.1021/nn405799t].

  8. Use of Continuous Exponential Families to Link Forms via Anchor Tests. Research Report. ETS RR-11-11

    ERIC Educational Resources Information Center

    Haberman, Shelby J.; Yan, Duanli

    2011-01-01

    Continuous exponential families are applied to linking test forms via an internal anchor. This application combines work on continuous exponential families for single-group designs and work on continuous exponential families for equivalent-group designs. Results are compared to those for kernel and equipercentile equating in the case of chained…

  9. The role of growth form and correlated traits in competitive ranking of six perennial ruderal plant species grown in unbalanced mixtures

    NASA Astrophysics Data System (ADS)

    Dietz, Hansjörg; Steinlein, Thomas; Ullmann, Isolde

    1998-02-01

    The competitive abilities of six perennial ruderal plants of three different growth forms were compared via yield measures using an additive diallel experimental design with unbalanced mixtures (9:3 or 3:9 plants per pot, respectively). Thus, in a given mixture species A was grown in two configurations: three individuals in centre position of the pot together with nine plants of species B in border position and vice versa. Effect competitive abilities as well as response competitive abilities of the species were significantly related to canopy height and plant biomass. The species with lower rosette growth form and smaller biomasses were weaker competitors than the species possessing elevated canopies along with higher biomasses, whereas total leaf area was not significantly correlated with competitive ability between species. Species differences in competitive ability were stronger between the plants grown in the central position than between those grown in the border position. Furthermore, interactions between species-specific traits and configuration could be observed, indicating the importance of species proportions and arrangement patterns for evaluation of competitive outcome in the field. The degree of complete transitivity of the competitive network of the six ruderal species, which was significantly higher than expected under the null model in our experimental design, also seemed to depend on species proportions in mixture. Shifts in root:shoot ratio of the centre plants when faced with competition by the border plants were in the direction of higher shoot allocation for the weak competitors with rosette growth form irrespective of the neighbour species, except for Bunias orientalis, which showed a more plastic response. The stronger competitors showed higher root allocation ( Urtica dioica) or were hardly affected at all. Consistent with the results of our experiment, the weaker competitors occur at rather frequently disturbed and therefore transient

  10. Revising traditional theory on the link between plant body size and fitness under competition: evidence from old-field vegetation.

    PubMed

    Tracey, Amanda J; Aarssen, Lonnie W

    2014-04-01

    The selection consequences of competition in plants have been traditionally interpreted based on a "size-advantage" hypothesis - that is, under intense crowding/competition from neighbors, natural selection generally favors capacity for a relatively large plant body size. However, this conflicts with abundant data, showing that resident species body size distributions are usually strongly right-skewed at virtually all scales within vegetation. Using surveys within sample plots and a neighbor-removal experiment, we tested: (1) whether resident species that have a larger maximum potential body size (MAX) generally have more successful local individual recruitment, and thus greater local abundance/density (as predicted by the traditional size-advantage hypothesis); and (2) whether there is a general between-species trade-off relationship between MAX and capacity to produce offspring when body size is severely suppressed by crowding/competition - that is, whether resident species with a larger MAX generally also need to reach a larger minimum reproductive threshold size (MIN) before they can reproduce at all. The results showed that MIN had a positive relationship with MAX across resident species, and local density - as well as local density of just reproductive individuals - was generally greater for species with smaller MIN (and hence smaller MAX). In addition, the cleared neighborhoods of larger target species (which had relatively large MIN) generally had - in the following growing season - a lower ratio of conspecific recruitment within these neighborhoods relative to recruitment of other (i.e., smaller) species (which had generally smaller MIN). These data are consistent with an alternative hypothesis based on a 'reproductive-economy-advantage' - that is, superior fitness under competition in plants generally requires not larger potential body size, but rather superior capacity to recruit offspring that are in turn capable of producing grand-offspring - and hence

  11. Revising traditional theory on the link between plant body size and fitness under competition: evidence from old-field vegetation

    PubMed Central

    Tracey, Amanda J; Aarssen, Lonnie W

    2014-01-01

    The selection consequences of competition in plants have been traditionally interpreted based on a “size-advantage” hypothesis – that is, under intense crowding/competition from neighbors, natural selection generally favors capacity for a relatively large plant body size. However, this conflicts with abundant data, showing that resident species body size distributions are usually strongly right-skewed at virtually all scales within vegetation. Using surveys within sample plots and a neighbor-removal experiment, we tested: (1) whether resident species that have a larger maximum potential body size (MAX) generally have more successful local individual recruitment, and thus greater local abundance/density (as predicted by the traditional size-advantage hypothesis); and (2) whether there is a general between-species trade-off relationship between MAX and capacity to produce offspring when body size is severely suppressed by crowding/competition – that is, whether resident species with a larger MAX generally also need to reach a larger minimum reproductive threshold size (MIN) before they can reproduce at all. The results showed that MIN had a positive relationship with MAX across resident species, and local density – as well as local density of just reproductive individuals – was generally greater for species with smaller MIN (and hence smaller MAX). In addition, the cleared neighborhoods of larger target species (which had relatively large MIN) generally had – in the following growing season – a lower ratio of conspecific recruitment within these neighborhoods relative to recruitment of other (i.e., smaller) species (which had generally smaller MIN). These data are consistent with an alternative hypothesis based on a ‘reproductive-economy-advantage’ – that is, superior fitness under competition in plants generally requires not larger potential body size, but rather superior capacity to recruit offspring that are in turn capable of producing grand

  12. Self-cross-linking biopolymers as injectable in situ forming biodegradable scaffolds.

    PubMed

    Balakrishnan, Biji; Jayakrishnan, A

    2005-06-01

    The injectable polymer scaffolds which are biocompatible and biodegradable are important biomaterials for tissue engineering and drug delivery. Hydrogels derived from natural proteins and polysaccharides are ideal scaffolds for tissue engineering since they resemble the extracellular matrices of the tissue comprised of various amino acids and sugar-based macromolecules. Here, we report a new class of hydrogels derived from oxidized alginate and gelatin. We show that periodate-oxidized sodium alginate having appropriate molecular weight and degree of oxidation rapidly cross-links proteins such as gelatin in the presence of small concentrations of sodium tetraborate (borax) to give injectable systems for tissue engineering, drug delivery and other medical applications. The rapid gelation in the presence of borax is attributed to the slightly alkaline pH of the medium as well as the ability of borax to complex with hydroxyl groups of polysaccharides. The effect of degree of oxidation and concentration of alginate dialdehyde, gelatin and borax on the speed of gelation was examined. As a general rule, the gelling time decreased with increase in concentration of oxidized alginate, gelatin and borax and increase in the degree of oxidation of alginate. Cross-linking parameters of the gel matrix were studied by swelling measurements and trinitrobenzene sulphonic acid (TNBS) assay. In general, the degree of cross-linking was found to increase with increase in the degree of oxidation of alginate, whereas the swelling ratio and the degree of swelling decreased. The gel was found to be biocompatible and biodegradable. The potential of the system as an injectable drug delivery vehicle and as a tissue-engineering scaffold is demonstrated by using primaquine as a model drug and by encapsulation of hepatocytes inside the gel matrix, respectively.

  13. Serological Evaluation of Immunity to the Varicella-Zoster Virus Based on a Novel Competitive Enzyme-Linked Immunosorbent Assay

    PubMed Central

    Liu, Jian; Ye, Xiangzhong; Jia, Jizong; Zhu, Rui; Wang, Lina; Chen, Chunye; Yang, Lianwei; Wang, Yongmei; Wang, Wei; Ye, Jianghui; Li, Yimin; Zhu, Hua; Zhao, Qinjian; Cheng, Tong; Xia, Ningshao

    2016-01-01

    Varicella-zoster virus (VZV) is a highly contagious agent of varicella and herpes zoster. Varicella can be lethal to immunocompromised patients, babies, HIV patients and other adults with impaired immunity. Serological evaluation of immunity to VZV will help determine which individuals are susceptible and evaluate vaccine effectiveness. A collection of 110 monoclonal antibodies (mAbs) were obtained by immunization of mice with membrane proteins or cell-free virus. The mAbs were well characterized, and a competitive sandwich ELISA (capture mAb: 8H6; labelling mAb: 1B11) was established to determine neutralizing antibodies in human serum with reference to the FAMA test. A total of 920 human sera were evaluated. The competitive sandwich ELISA showed a sensitivity of 95.6%, specificity of 99.77% and coincidence of 97.61% compared with the fluorescent-antibody-to-membrane-antigen (FAMA) test. The capture mAb 8H6 was characterized as a specific mAb for VZV ORF9, a membrane-associated tegument protein that interacts with glycoprotein E (gE), glycoprotein B (gB) and glycoprotein C (gC). The labelling mAb 1B11 was characterized as a complement-dependent neutralizing mAb specific for the immune-dominant epitope located on gE, not on other VZV glycoproteins. The established competitive sandwich ELISA could be used as a rapid and high-throughput method for evaluating immunity to VZV. PMID:26853741

  14. Serological Evaluation of Immunity to the Varicella-Zoster Virus Based on a Novel Competitive Enzyme-Linked Immunosorbent Assay.

    PubMed

    Liu, Jian; Ye, Xiangzhong; Jia, Jizong; Zhu, Rui; Wang, Lina; Chen, Chunye; Yang, Lianwei; Wang, Yongmei; Wang, Wei; Ye, Jianghui; Li, Yimin; Zhu, Hua; Zhao, Qinjian; Cheng, Tong; Xia, Ningshao

    2016-01-01

    Varicella-zoster virus (VZV) is a highly contagious agent of varicella and herpes zoster. Varicella can be lethal to immunocompromised patients, babies, HIV patients and other adults with impaired immunity. Serological evaluation of immunity to VZV will help determine which individuals are susceptible and evaluate vaccine effectiveness. A collection of 110 monoclonal antibodies (mAbs) were obtained by immunization of mice with membrane proteins or cell-free virus. The mAbs were well characterized, and a competitive sandwich ELISA (capture mAb: 8H6; labelling mAb: 1B11) was established to determine neutralizing antibodies in human serum with reference to the FAMA test. A total of 920 human sera were evaluated. The competitive sandwich ELISA showed a sensitivity of 95.6%, specificity of 99.77% and coincidence of 97.61% compared with the fluorescent-antibody-to-membrane-antigen (FAMA) test. The capture mAb 8H6 was characterized as a specific mAb for VZV ORF9, a membrane-associated tegument protein that interacts with glycoprotein E (gE), glycoprotein B (gB) and glycoprotein C (gC). The labelling mAb 1B11 was characterized as a complement-dependent neutralizing mAb specific for the immune-dominant epitope located on gE, not on other VZV glycoproteins. The established competitive sandwich ELISA could be used as a rapid and high-throughput method for evaluating immunity to VZV. PMID:26853741

  15. Mass spectrometric detection of cross-linked fatty acids formed during radical-induced lesion of lipid membranes.

    PubMed Central

    Frank, H; Thiel, D; MacLeod, J

    1989-01-01

    A mass spectrometric method is described for the quantitative determination of dimers of polyunsaturated fatty acids (PUFA) formed in the hepatic endoplasmic reticulum of rats upon inhalation of tetrachloromethane. The results show that dimers account for a considerable fraction of microsomal PUFA which disappear during CCl4 metabolism. Cross-linking of the membrane lipids of the endoplasmic reticulum seems to be a significant process with respect to cell toxicity. PMID:2764908

  16. Thermally Reversible Physically Cross-Linked Hybrid Network Hydrogels Formed by Thermosensitive Hairy Nanoparticles.

    PubMed

    Wright, Roger A E; Henn, Daniel M; Zhao, Bin

    2016-08-18

    This Article reports on thermally induced reversible formation of physically cross-linked, three-dimensional network hydrogels from aqueous dispersions of thermosensitive diblock copolymer brush-grafted silica nanoparticles (hairy NPs). The hairy NPs consisted of a silica core, a water-soluble polyelectrolyte inner block of poly(2-(methacryloyloxy)ethyltrimethylammonium iodide), and a thermosensitive poly(methoxydi(ethylene glycol) methacrylate) (PDEGMMA) outer block synthesized by sequential surface-initiated atom transfer radical polymerizations and postpolymerization quaternization of tertiary amine moieties. Moderately concentrated dispersions of these hairy nanoparticles in water underwent thermally induced reversible transitions between flowing liquids to self-supporting gels upon heating. The gelation was driven by the lower critical solution temperature (LCST) transition of the PDEGMMA outer block, which upon heating self-associated into hydrophobic domains acting as physical cross-linking points for the gel network. Rheological studies showed that the sol-gel transition temperature decreased with increasing hairy NP concentration, and the gelation was achieved at concentrations as low as 3 wt %. PMID:27455167

  17. Detection of Ganoderic Acid A in Ganoderma lingzhi by an Indirect Competitive Enzyme-Linked Immunosorbent Assay.

    PubMed

    Sakamoto, Seiichi; Kohno, Toshitaka; Shimizu, Kuniyoshi; Tanaka, Hiroyuki; Morimoto, Satoshi

    2016-05-01

    Ganoderma is a genus of medicinal mushroom traditionally used for treating various diseases. Ganoderic acid A is one of the major bioactive Ganoderma triterpenoids isolated from Ganoderma species. Herein, we produced a highly specific monoclonal antibody against ganoderic acid A (MAb 12 A) and developed an indirect competitive ELISA for the highly sensitive detection of ganoderic acid A in Ganoderma lingzhi, with a limit of detection of 6.10 ng/mL. Several validation analyses support the accuracy and reliability of the developed indirect competitive ELISA for use in the quality control of Ganoderma based on ganoderic acid A content. Furthermore, quantitative analysis of ganoderic acid A in G. lingzhi revealed that the pileus exhibits the highest ganoderic acid A content compared with the stipe and spore of the fruiting body; the best extraction efficiency was found when 50 % ethanol was used, which suggests the use of a strong liquor to completely harness the potential of Ganoderma triterpenoids in daily life. PMID:27093250

  18. The Link between Form and Meaning in American Sign Language: Lexical Processing Effects

    ERIC Educational Resources Information Center

    Thompson, Robin L.; Vinson, David P.; Vigliocco, Gabriella

    2009-01-01

    Signed languages exploit iconicity (the transparent relationship between meaning and form) to a greater extent than spoken languages. where it is largely limited to onomatopoeia. In a picture-sign matching experiment measuring reaction times, the authors examined the potential advantage of iconicity both for 1st- and 2nd-language learners of…

  19. Linking Outcomes from Peabody Picture Vocabulary Test Forms Using Item Response Models

    ERIC Educational Resources Information Center

    Hoffman, Lesa; Templin, Jonathan; Rice, Mabel L.

    2012-01-01

    Purpose: The present work describes how vocabulary ability as assessed by 3 different forms of the Peabody Picture Vocabulary Test (PPVT; Dunn & Dunn, 1997) can be placed on a common latent metric through item response theory (IRT) modeling, by which valid comparisons of ability between samples or over time can then be made. Method: Responses from…

  20. Friendship Conflict, Conflict Responses, and Instability: Unique Links to Anxious and Angry Forms of Rejection Sensitivity

    ERIC Educational Resources Information Center

    Croft, Carissa D.; Zimmer-Gembeck, Melanie J.

    2014-01-01

    Rejection sensitivity (RS) instigates conflict and prompts maladaptive conflict responses within romantic relationships. We tested whether RS had similar effects within friendships (N = 262, X[subscript age] = 11.7) by investigating whether (a) RS was associated with more frequent conflict, (b) two RS forms prompted different conflict responses,…

  1. Linking structure to fragility in bulk metallic glass-forming liquids

    SciTech Connect

    Wei, Shuai E-mail: m.stolpe@mx.uni-saarland.de; Stolpe, Moritz E-mail: m.stolpe@mx.uni-saarland.de; Gross, Oliver; Gallino, Isabella; Hembree, William; Busch, Ralf; Evenson, Zach; Bednarcik, Jozef; Kruzic, Jamie J.

    2015-05-04

    Using in-situ synchrotron X-ray scattering, we show that the structural evolution of various bulk metallic glass-forming liquids can be quantitatively connected to their viscosity behavior in the supercooled liquid near T{sub g}. The structural signature of fragility is identified as the temperature dependence of local dilatation on distinct key atomic length scales. A more fragile behavior results from a more pronounced thermally induced dilatation of the structure on a length scale of about 3 to 4 atomic diameters, coupled with shallower temperature dependence of structural changes in the nearest neighbor environment. These findings shed light on the structural origin of viscous slowdown during undercooling of bulk metallic glass-forming liquids and demonstrate the promise of predicting the properties of bulk metallic glasses from the atomic scale structure.

  2. Supramolecular hydrogels formed from poly(viologen) cross-linked with cyclodextrin dimers and their physical properties

    PubMed Central

    Takashima, Yoshinori; Yuting, Yang; Otsubo, Miyuki; Yamaguchi, Hiroyasu

    2012-01-01

    Summary Supramolecular materials with noncovalent bonds have attracted much attention due to their exclusive properties differentiating them from materials formed solely by covalent bonds. Especially interesting are rotor molecules of topological complexes that shuttle along a polymer chain. The shuttling of these molecules should greatly improve the tension strength. Our research employs cyclodextrin (CD) as a host molecule, because CD effectively forms polyrotaxanes with polymers. Herein we report the formation of supramolecular hydrogels with an α-CD dimer (α,α-CD dimer) as a topological linker molecule, and a viologen polymer (VP) as the polymer chain. The supramolecular hydrogel of α,α-CD dimer/VP forms a self-standing gel, which does not relax (G' > G'') in the frequency range 0.01–10 rad·s−1. On the other hand, the supramolecular hydrogel decomposes upon addition of bispyridyl decamethylene (PyC10Py) as a competitive guest. Moreover, the β-CD dimer (β,β-CD dimer) with VP does not form a supramolecular hydrogel, indicating that complexation between the C10 unit of VP and the α-CD unit of the α,α-CD dimer plays an important role in the formation of supramolecular hydrogels. PMID:23209491

  3. The Link Between Form and Meaning in American Sign Language: Lexical Processing Effects

    PubMed Central

    Thompson, Robin L.; Vinson, David P.; Vigliocco, Gabriella

    2013-01-01

    Signed languages exploit iconicity (the transparent relationship between meaning and form) to a greater extent than spoken languages. where it is largely limited to onomatopoeia. In a picture–sign matching experiment measuring reaction times, the authors examined the potential advantage of iconicity both for 1st- and 2nd-language learners of American Sign Language (ASL). The results show that native ASL signers are faster to respond when a specific property iconically represented in a sign is made salient in the corresponding picture, thus providing evidence that a closer mapping between meaning and form can aid in lexical retrieval. While late 2nd-language learners appear to use iconicity as an aid to learning sign, they did not show the same facilitation effect as native ASL signers, suggesting that the task tapped into more automatic language processes. Overall, the findings suggest that completely arbitrary mappings between meaning and form may not be more advantageous in language and that, rather, arbitrariness may simply be an accident of modality. PMID:19271866

  4. The link between form and meaning in American Sign Language: lexical processing effects.

    PubMed

    Thompson, Robin L; Vinson, David P; Vigliocco, Gabriella

    2009-03-01

    Signed languages exploit iconicity (the transparent relationship between meaning and form) to a greater extent than spoken languages. where it is largely limited to onomatopoeia. In a picture-sign matching experiment measuring reaction times, the authors examined the potential advantage of iconicity both for 1st- and 2nd-language learners of American Sign Language (ASL). The results show that native ASL signers are faster to respond when a specific property iconically represented in a sign is made salient in the corresponding picture, thus providing evidence that a closer mapping between meaning and form can aid in lexical retrieval. While late 2nd-language learners appear to use iconicity as an aid to learning sign (R. Campbell, P. Martin, & T. White, 1992), they did not show the same facilitation effect as native ASL signers, suggesting that the task tapped into more automatic language processes. Overall, the findings suggest that completely arbitrary mappings between meaning and form may not be more advantageous in language and that, rather, arbitrariness may simply be an accident of modality.

  5. Strongly linked current flow in polycrystalline forms of the superconductor MgB2.

    PubMed

    Larbalestier, D C; Cooley, L D; Rikel, M O; Polyanskii, A A; Jiang, J; Patnaik, S; Cai, X Y; Feldmann, D M; Gurevich, A; Squitieri, A A; Naus, M T; Eom, C B; Hellstrom, E E; Cava, R J; Regan, K A; Rogado, N; Hayward, M A; He, T; Slusky, J S; Khalifah, P; Inumaru, K; Haas, M

    2001-03-01

    The discovery of superconductivity at 39 K in magnesium diboride, MgB2, raises many issues, a critical one being whether this material resembles a high-temperature copper oxide superconductor or a low-temperature metallic superconductor in terms of its behaviour in strong magnetic fields. Although the copper oxides exhibit very high transition temperatures, their in-field performance is compromized by their large anisotropy, the result of which is to restrict high bulk current densities to a region much less than the full magnetic-field-temperature (H-T) space over which superconductivity is found. Moreover, the weak coupling across grain boundaries makes transport current densities in untextured polycrystalline samples low and strongly sensitive to magnetic field. Here we report that, despite the multiphase, untextured, microscale, subdivided nature of our MgB2 samples, supercurrents flow throughout the material without exhibiting strong sensitivity to weak magnetic fields. Our combined magnetization, magneto-optical, microscopy and X-ray investigations show that the supercurrent density is mostly determined by flux pinning, rather than by the grain boundary connectivity. Our results therefore suggest that this new superconductor class is not compromized by weak-link problems, a conclusion of significance for practical applications if higher temperature analogues of this compound can be discovered.

  6. Ordered ferrimagnetic form of ferrihydrite reveals links among structure, composition, and magnetism

    SciTech Connect

    Michel, F. Marc; Barrón, Vidal; Torrent, José; Morales, María P.; Serna, Carlos J.; Boily, Jean-François; Liu, Qingsong; Ambrosini, Andrea; Cismasu, A. Cristina; Brown, Jr., Gordon E.

    2010-11-19

    The natural nanomineral ferrihydrite is an important component of many environmental and soil systems and has been implicated as the inorganic core of ferritin in biological systems. Knowledge of its basic structure, composition, and extent of structural disorder is essential for understanding its reactivity, stability, and magnetic behavior, as well as changes in these properties during aging. Here we investigate compositional, structural, and magnetic changes that occur upon aging of '2-line' ferrihydrite in the presence of adsorbed citrate at elevated temperature. Whereas aging under these conditions ultimately results in the formation of hematite, analysis of the atomic pair distribution function and complementary physicochemical and magnetic data indicate formation of an intermediate ferrihydrite phase of larger particle size with few defects, more structural relaxation and electron spin ordering, and pronounced ferrimagnetism relative to its disordered ferrihydrite precursor. Our results represent an important conceptual advance in understanding the nature of structural disorder in ferrihydrite and its relation to the magnetic structure and also serve to validate a controversial, recently proposed structural model for this phase. In addition, the pathway we identify for forming ferrimagnetic ferrihydrite potentially explains the magnetic enhancement that typically precedes formation of hematite in aerobic soil and weathering environments. Such magnetic enhancement has been attributed to the formation of poorly understood, nano-sized ferrimagnets from a ferrihydrite precursor. Whereas elevated temperatures drive the transformation on timescales feasible for laboratory studies, our results also suggest that ferrimagnetic ferrihydrite could form naturally at ambient temperature given sufficient time.

  7. Cadherin mutation linked to resistance to Cry1Ac affects male paternity and sperm competition in Helicoverpa armigera

    PubMed Central

    Zhang, Haonan; Du, Bing; Higginson, Dawn M.; Carrière, Yves; Wu, Yidong

    2015-01-01

    Several lepidopteran pests of cotton have cadherin-based resistance to the Bacillus thuringiensis (Bt) toxin Cry1Ac. Cadherins are transmembrane proteins that mediate cell-cell adhesion and tissue morphogenesis, suggesting that fitness costs associated with cadherin mutations may be present in many aspects of life history. To evaluate whether cadherin-based resistance is associated with fitness costs reducing male paternity in Helicoverpa armigera, we examined the effects of a major cadherin resistance allele on sperm competition within and between male ejaculates. When homozygous resistant and susceptible males competed for fertilization of a homozygous resistant or susceptible female, fertilization success was high in males with a different cadherin genotype than females and low in males with the same cadherin genotype as females. Single matings between heterozygous males and susceptible females produced offspring within typical Mendelian ratios. Heterozygous males mated to resistant females, however, resulted in a disproportionate number of heterozygous offspring. While these results show that cadherin-based resistance to Cry1Ac has significant impacts on paternity in H. armigera, there was no evidence that costs associated with resistance consistently reduced male paternity. Rather, effects of cadherin-based resistance on paternity depended on interactions between male and female genotypes and differed when males or sperm competed for fertilization of females, which complicates assessment of impacts of cadherin resistance alleles on resistance evolution. PMID:25220924

  8. A sensitive and robust competitive enzyme-linked immunosorbent assay for Brazil nut ( Bertholletia excelsa L.) detection.

    PubMed

    Sharma, Girdhari M; Roux, Kenneth H; Sathe, Shridhar K

    2009-01-28

    Undeclared Brazil nut residue in food products is of great concern because it can trigger life-threatening allergic reactions in sensitive patients. A rabbit polyclonal antibody-based competitive ELISA (IC(50) = 23.2 +/- 9 ng/mL, n = 76) with good sensitivity, detection range of 10-90 ng/mL, was developed. The ELISA could detect Brazil nut seed proteins over a pH range of 5-12. The optimal pH range for the detection assay was 7-10. Among the 66 tested foods/ingredients, only cinnamon exhibited statistically significant interference (1.36%, p = 0.05). Exposing Brazil nut seeds to processing did not adversely affect the nut seed protein detection using the assay. Brazil nut seed protein recovery from 100 mg of foods spiked with 10 and 1 microg of soluble Brazil nut proteins or 100 and 10 microg of defatted Brazil nut flour exhibited a wide recovery range, 63-315%, indicating protein-food matrix interaction. PMID:19113944

  9. Subnanometer atomic force microscopy of peptide–mineral interactions links clustering and competition to acceleration and catastrophe

    PubMed Central

    Friddle, R. W.; Weaver, M. L.; Qiu, S. R.; Wierzbicki, A.; Casey, W. H.; De Yoreo, J. J.

    2010-01-01

    In vitro observations have revealed major effects on the structure, growth, and composition of biomineral phases, including stabilization of amorphous precursors, acceleration and inhibition of kinetics, and alteration of impurity signatures. However, deciphering the mechanistic sources of these effects has been problematic due to a lack of tools to resolve molecular structures on mineral surfaces during growth. Here we report atomic force microscopy investigations using a system designed to maximize resolution while minimizing contact force. By imaging the growth of calcium-oxalate monohydrate under the influence of aspartic-rich peptides at single-molecule resolution, we reveal how the unique interactions of polypeptides with mineral surfaces lead to acceleration, inhibition, and switching of growth between two distinct states. Interaction with the positively charged face of calcium-oxalate monohydrate leads to formation of a peptide film, but the slow adsorption kinetics and gradual relaxation to a well-bound state result in time-dependent effects. These include a positive feedback between peptide adsorption and step inhibition described by a mathematical catastrophe that results in growth hysteresis, characterized by rapid switching from fast to near-zero growth rates for very small reductions in supersaturation. Interactions with the negatively charged face result in formation of peptide clusters that impede step advancement. The result is a competition between accelerated solute attachment and inhibition due to blocking of the steps by the clusters. The findings have implications for control of pathological mineralization and suggest artificial strategies for directing crystallization. PMID:20018743

  10. A sensitive and robust competitive enzyme-linked immunosorbent assay for Brazil nut ( Bertholletia excelsa L.) detection.

    PubMed

    Sharma, Girdhari M; Roux, Kenneth H; Sathe, Shridhar K

    2009-01-28

    Undeclared Brazil nut residue in food products is of great concern because it can trigger life-threatening allergic reactions in sensitive patients. A rabbit polyclonal antibody-based competitive ELISA (IC(50) = 23.2 +/- 9 ng/mL, n = 76) with good sensitivity, detection range of 10-90 ng/mL, was developed. The ELISA could detect Brazil nut seed proteins over a pH range of 5-12. The optimal pH range for the detection assay was 7-10. Among the 66 tested foods/ingredients, only cinnamon exhibited statistically significant interference (1.36%, p = 0.05). Exposing Brazil nut seeds to processing did not adversely affect the nut seed protein detection using the assay. Brazil nut seed protein recovery from 100 mg of foods spiked with 10 and 1 microg of soluble Brazil nut proteins or 100 and 10 microg of defatted Brazil nut flour exhibited a wide recovery range, 63-315%, indicating protein-food matrix interaction.

  11. Hydraulic integration and shrub growth form linked across continental aridity gradients

    PubMed Central

    Schenk, H. Jochen; Espino, Susana; Goedhart, Christine M.; Nordenstahl, Marisa; Cabrera, Hugo I. Martinez; Jones, Cynthia S.

    2008-01-01

    Both engineered hydraulic systems and plant hydraulic systems are protected against failure by resistance, reparability, and redundancy. A basic rule of reliability engineering is that the level of independent redundancy should increase with increasing risk of fatal system failure. Here we show that hydraulic systems of plants function as predicted by this engineering rule. Hydraulic systems of shrubs sampled along two transcontinental aridity gradients changed with increasing aridity from highly integrated to independently redundant modular designs. Shrubs in humid environments tend to be hydraulically integrated, with single, round basal stems, whereas dryland shrubs typically have modular hydraulic systems and multiple, segmented basal stems. Modularity is achieved anatomically at the vessel-network scale or developmentally at the whole-plant scale through asymmetric secondary growth, which results in a semiclonal or clonal shrub growth form that appears to be ubiquitous in global deserts. PMID:18678893

  12. Mutations in PNPLA6 are linked to photoreceptor degeneration and various forms of childhood blindness

    PubMed Central

    Kmoch, S.; Majewski, J.; Ramamurthy, V.; Cao, S.; Fahiminiya, S.; Ren, H.; MacDonald, I.M.; Lopez, I.; Sun, V.; Keser, V.; Khan, A.; Stránecký, V.; Hartmannová, H.; Přistoupilová, A.; Hodaňová, K.; Piherová, L.; Kuchař, L.; Baxová, A.; Chen, R.; Barsottini, O.G.P.; Pyle, A.; Griffin, H.; Splitt, M.; Sallum, J.; Tolmie, J.L.; Sampson, J.R.; Chinnery, P.; Canada, Care4Rare; Banin, E.; Sharon, D.; Dutta, S.; Grebler, R.; Helfrich-Foerster, C.; Pedroso, J.L.; Kretzschmar, D.; Cayouette, M.; Koenekoop, R.K.

    2015-01-01

    Blindness due to retinal degeneration affects millions of people worldwide, but many disease-causing mutations remain unknown. PNPLA6 encodes the patatin-like phospholipase domain containing protein 6, also known as neuropathy target esterase (NTE), which is the target of toxic organophosphates that induce human paralysis due to severe axonopathy of large neurons. Mutations in PNPLA6 also cause human spastic paraplegia characterized by motor neuron degeneration. Here we identify PNPLA6 mutations in childhood blindness in seven families with retinal degeneration, including Leber congenital amaurosis and Oliver McFarlane syndrome. PNPLA6 localizes mostly at the inner segment plasma membrane in photo-receptors and mutations in Drosophila PNPLA6 lead to photoreceptor cell death. We also report that lysophosphatidylcholine and lysophosphatidic acid levels are elevated in mutant Drosophila. These findings show a role for PNPLA6 in photoreceptor survival and identify phospholipid metabolism as a potential therapeutic target for some forms of blindness. PMID:25574898

  13. Competitive amperometric immunosensor based on covalent linking of a protein conjugate to dendrimer-functionalised nanogold substrate for the determination of 2,4,6-trinitrotoluene.

    PubMed

    Giannetto, Marco; Maiolini, Elisabetta; Ferri, Elida Nora; Girotti, Stefano; Mori, Giovanni; Careri, Maria

    2013-01-01

    A new amperometric immunosensor for 2,4,6-trinitrotoluene based on the working principle of competitive enzyme-linked immunosorbent assay was developed and characterised. An electrodeposited nanogold substrate was functionalised by deposition of self-assembled monolayers of 2-aminoethanethiol as linkers for the subsequent immobilisation of polyamidoaminic dendrimers. Our approach makes use of those dendrimers to anchor a trinitrobenzene-ovalbumin conjugate on the electrode surface. The immunosensor was tested and validated for the determination of 2,4,6-trinitrotoluene showing high selectivity with respect to other nitroaromatic compounds, a limit of detection of 4.8 ng/mL and a limit of quantitation of 6 ng/mL. The immunosensor was tested for the quantification of the analyte in spiked soils and in a real sample of post-blast soil, evidencing a good recovery rate (113 %).

  14. The form of sexual selection arising from male-male competition depends on the presence of females in the social environment.

    PubMed

    Procter, D S; Moore, A J; Miller, C W

    2012-05-01

    Sexual selection arises from social interactions, and if social environments vary so too should sexual selection. For example, male-male competition often occurs either in the presence or in the absence of females, and such changes in the social environment could affect the form and strength of sexual selection. Here we examine how the presence of a female influences selection arising from male-male competition in a leaf-footed cactus bug, Narnia femorata, which has a resource defence mating system. Males compete for territories on cacti because females lay eggs on the cactus plants. Females are not always present when this competition first occurs; however, the presence or absence of the female matters. We found that both the form and strength of selection on male traits, those traits that influenced success in intrasexual competition, depended on the social context. When a female was not present, male size and the area of the sexually dimorphic hind legs was only marginally important to winning a contest. However, males with larger overall size and leg area were more likely to win in the presence of a female. There was also positive quadratic selection on these traits when a female was present with both the largest and the smallest males winning. The implication is unexpected alternative strategies when females are present. Our results support the notion that sexual selection should be studied under all relevant social contexts.

  15. The link between form and meaning in British sign language: effects of iconicity for phonological decisions.

    PubMed

    Thompson, Robin L; Vinson, David P; Vigliocco, Gabriella

    2010-07-01

    Signed languages exploit the visual/gestural modality to create iconic expression across a wide range of basic conceptual structures in which the phonetic resources of the language are built up into an analogue of a mental image (Taub, 2001). Previously, we demonstrated a processing advantage when iconic properties of signs were made salient in a corresponding picture during a picture and sign matching task (Thompson, Vinson, & Vigliocco, 2009). The current study investigates the extent of iconicity effects with a phonological decision task (does the sign involve straight or curved fingers?) in which the meaning of the sign is irrelevant. The results show that iconicity is a significant predictor of response latencies and accuracy, with more iconic signs leading to slower responses and more errors. We conclude that meaning is activated automatically for highly iconic properties of a sign, and this leads to interference in making form-based decisions. Thus, the current study extends previous work by demonstrating that iconicity effects permeate the entire language system, arising automatically even when access to meaning is not needed. PMID:20565217

  16. Linking Satellites Via Earth "Hot Spots" and the Internet to Form Ad Hoc Constellations

    NASA Technical Reports Server (NTRS)

    Mandl, Dan; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix; Lee, Richard Q.; Romanofsky, Robert; Zaman, Afoz; Popovic, Zoya

    2004-01-01

    As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet. the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in

  17. Warming off southwestern Japan linked to distributional shifts of subtidal canopy-forming seaweeds

    PubMed Central

    Tanaka, Kouki; Taino, Seiya; Haraguchi, Hiroko; Prendergast, Gabrielle; Hiraoka, Masanori

    2012-01-01

    To assess distributional shifts of species in response to recent warming, historical distribution records are the most requisite information. The surface seawater temperature (SST) of Kochi Prefecture, southwestern Japan on the western North Pacific, has significantly risen, being warmed by the Kuroshio Current. Past distributional records of subtidal canopy-forming seaweeds (Laminariales and Fucales) exist at about 10-year intervals from the 1970s, along with detailed SST datasets at several sites along Kochi's >700 km coastline. In order to provide a clear picture of distributional shifts of coastal marine organisms in response to warming SST, we observed the present distribution of seaweeds and analyzed the SST datasets to estimate spatiotemporal SST trends in this coastal region. We present a large increase of 0.3°C/decade in the annual mean SST of this area over the past 40 years. Furthermore, a comparison of the previous and present distributions clearly showed the contraction of temperate species' distributional ranges and expansion of tropical species' distributional ranges in the seaweeds. Although the main temperate kelp Ecklonia (Laminariales) had expanded their distribution during periods of cooler SST, they subsequently declined as the SST warmed. Notably, the warmest SST of the 1997–98 El Niño Southern Oscillation event was the most likely cause of a widespread destruction of the kelp populations; no recovery was found even in the present survey at the formerly habitable sites where warm SSTs have been maintained. Temperate Sargassum spp. (Fucales) that dominated widely in the 1970s also declined in accordance with recent warming SSTs. In contrast, the tropical species, S. ilicifolium, has gradually expanded its distribution to become the most conspicuously dominant among the present observations. Thermal gradients, mainly driven by the warming Kuroshio Current, are presented as an explanation for the successive changes in both temperate and

  18. Dimeric Ube2g2 simultaneously engages donor and acceptor ubiquitins to form Lys48-linked ubiquitin chains

    PubMed Central

    Liu, Weixiao; Shang, Yongliang; Zeng, Yan; Liu, Chao; Li, Yanchang; Zhai, Linhui; Wang, Pan; Lou, Jizhong; Xu, Ping; Ye, Yihong; Li, Wei

    2014-01-01

    Cellular adaptation to proteotoxic stress at the endoplasmic reticulum (ER) depends on Lys48-linked polyubiquitination by ER-associated ubiquitin ligases (E3s) and subsequent elimination of ubiquitinated retrotranslocation products by the proteasome. The ER-associated E3 gp78 ubiquitinates misfolded proteins by transferring preformed Lys48-linked ubiquitin chains from the cognate E2 Ube2g2 to substrates. Here we demonstrate that Ube2g2 synthesizes linkage specific ubiquitin chains by forming an unprecedented homodimer: The dimerization of Ube2g2, mediated primarily by electrostatic interactions between two Ube2g2s, is also facilitated by the charged ubiquitin molecules. Mutagenesis studies show that Ube2g2 dimerization is required for ER-associated degradation (ERAD). In addition to E2 dimerization, we show that a highly conserved arginine residue in the donor Ube2g2 senses the presence of an aspartate in the acceptor ubiquitin to position only Lys48 of ubiquitin in proximity to the donor E2 active site. These results reveal an unanticipated mode of E2 self-association that allows the E2 to effectively engage two ubiquitins to specifically synthesize Lys48-linked ubiquitin chains. PMID:24366945

  19. A competitive enzyme-linked immunosorbent assay to quantitate acyclovir and BW B759U in human plasma and urine.

    PubMed Central

    Tadepalli, S M; Quinn, R P; Averett, D R

    1986-01-01

    A simple and sensitive enzyme-linked immunosorbent assay for the detection and quantitation of acyclovir in human plasma and urine was developed. Acyclovir immobilized on a solid phase and free acyclovir in the sample solution were allowed to compete for a limited amount of anti-acyclovir monoclonal antibody. The specific antibody bound to the immobilized acyclovir was detected by the use of alkaline phosphatase-conjugated anti-mouse immunoglobulin. The resulting enzyme activity was inversely related to acyclovir concentration in the sample. The Hill plot of standard acyclovir concentrations was linear over a 100-fold concentration range, with a lower detection limit of 0.2 nM and a concentration of soluble ligand displacing 50% of available antibody of approximately 1 nM. The metabolites of acyclovir cross-reacted minimally, and there was no detectable interference by various unrelated compounds tested in the assay. However, BW B759U [9-(2-hydroxy-1-hydroxymethylethoxy)methylguanine], a congener of acyclovir, cross-reacted significantly. As a consequence, the assay was found useful in measuring the concentrations of BW B759U in clinical samples devoid of acyclovir. PMID:3488016

  20. Rapid competitive enzyme-linked immunosorbent assay using a monoclonal antibody reacting with a 15-kilodalton tegumental antigen of Schistosoma mansoni for serodiagnosis of schistosomiasis.

    PubMed Central

    Da Silva, A J; Piuvezam, M R; de Moura, H; Maddison, S; Peralta, J M

    1993-01-01

    A competitive enzyme-linked immunosorbent assay (CELISA) for antibody detection was developed by using a monoclonal antibody which reacts with a 15-kDa tegumental antigen of the adult worm of Schistosoma mansoni. This monoclonal antibody was not able to react with antigens of Schistosoma japonicum or Schistosoma haematobium in enzyme-linked immunoelectrotransfer blot (EITB) and indirect immunofluorescence tests. The assay was performed in a period of 1 h using an adult worm crude extract antigen. To evaluate the CELISA, a total of 73 serum samples was analyzed: 35 were from S. mansoni-infected patients, 23 were from individuals with parasitic infections other than schistosomiasis, and 14 were from healthy individuals. All serum samples from healthy individuals and from patients infected with other parasites were negative, as were two (6%) samples from patients infected with S. mansoni. EITB analysis showed that 32 of 33 CELISA-positive samples were positive in the EITB but with different patterns of reactivity. A 15-kDa protein reacted with 60% of serum samples, and a 60-kDa protein showed the highest level of reactivity (85%). The two samples from patients infected with S. mansoni that were negative in the CELISA reacted with 70-, 60-, 50-, 47-, and 38-kDa proteins. One sample, positive in CELISA, did not react with proteins of the antigenic extract. Images PMID:8408548

  1. A VAPB mutant linked to amyotrophic lateral sclerosis generates a novel form of organized smooth endoplasmic reticulum.

    PubMed

    Fasana, Elisa; Fossati, Matteo; Ruggiano, Annamaria; Brambillasca, Silvia; Hoogenraad, Casper C; Navone, Francesca; Francolini, Maura; Borgese, Nica

    2010-05-01

    VAPB (vesicle-associated membrane protein-associated protein B) is an endoplasmic reticulum (ER)-resident tail-anchored adaptor protein involved in lipid transport. A dominantly inherited mutant, P56S-VAPB, causes a familial form of amyotrophic lateral sclerosis (ALS) and forms poorly characterized inclusion bodies in cultured cells. To provide a cell biological basis for the understanding of mutant VAPB pathogenicity, we investigated its biogenesis and the inclusions that it generates. Translocation assays in cell-free systems and in cultured mammalian cells were used to investigate P56S-VAPB membrane insertion, and the inclusions were characterized by confocal imaging and electron microscopy. We found that mutant VAPB inserts post-translationally into ER membranes in a manner indistinguishable from the wild-type protein but that it rapidly clusters to form inclusions that remain continuous with the rest of the ER. Inclusions were induced by the mutant also when it was expressed at levels comparable to the endogenous wild-type protein. Ultrastructural analysis revealed that the inclusions represent a novel form of organized smooth ER (OSER) consisting in a limited number of parallel cisternae (usually 2 or 3) interleaved by a approximately 30 nm-thick electron-dense cytosolic layer. Our results demonstrate that the ALS-linked VAPB mutant causes dramatic ER restructuring that may underlie its pathogenicity in motoneurons.

  2. Complex competitive systems and competitive thermodynamics.

    PubMed

    Klimenko, A Y

    2013-01-13

    This publication reviews the framework of abstract competition, which is aimed at studying complex systems with competition in their generic form. Although the concept of abstract competition has been derived from a specific field--modelling of mixing in turbulent reacting flows--this concept is, generally, not attached to a specific phenomenon or application. Two classes of competition rules, transitive and intransitive, need to be distinguished. Transitive competitions are shown to be consistent (at least qualitatively) with thermodynamic principles, which allows for introduction of special competitive thermodynamics. Competitive systems can thus be characterized by thermodynamic quantities (such as competitive entropy and competitive potential), which determine that the predominant direction of evolution of the system is directed towards higher competitiveness. There is, however, an important difference: while conventional thermodynamics is constrained by its zeroth law and is fundamentally transitive, the transitivity of competitive thermodynamics depends on the transitivity of the competition rules. The analogy with conventional thermodynamics weakens as competitive systems become more intransitive, while strongly intransitive competitions can display types of behaviour associated with complexity: competitive cooperation and leaping cycles. Results of simulations demonstrating complex behaviour in abstract competitions are presented in the electronic supplementary material.

  3. 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.

    PubMed

    Ejby, Morten; Fredslund, Folmer; Andersen, Joakim Mark; Vujičić Žagar, Andreja; Henriksen, Jonas Rosager; Andersen, Thomas Lars; Svensson, Birte; Slotboom, Dirk Jan; Abou Hachem, Maher

    2016-09-16

    The molecular details and impact of oligosaccharide uptake by distinct human gut microbiota (HGM) are currently not well understood. Non-digestible dietary galacto- and gluco-α-(1,6)-oligosaccharides from legumes and starch, respectively, are preferentially fermented by mainly bifidobacteria and lactobacilli in the human gut. Here we show that the solute binding protein (BlG16BP) associated with an ATP binding cassette (ABC) transporter from the probiotic Bifidobacterium animalis subsp. lactis Bl-04 binds α-(1,6)-linked glucosides and galactosides of varying size, linkage, and monosaccharide composition with preference for the trisaccharides raffinose and panose. This preference is also reflected in the α-(1,6)-galactoside uptake profile of the bacterium. Structures of BlG16BP in complex with raffinose and panose revealed the basis for the remarkable ligand binding plasticity of BlG16BP, which recognizes the non-reducing α-(1,6)-diglycoside in its ligands. BlG16BP homologues occur predominantly in bifidobacteria and a few Firmicutes but lack in other HGMs. Among seven bifidobacterial taxa, only those possessing this transporter displayed growth on α-(1,6)-glycosides. Competition assays revealed 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. PMID:27502277

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

    PubMed Central

    2011-01-01

    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. PMID:21970317

  5. A novel in situ-formed hydrogel wound dressing by the photocross-linking of a chitosan derivative.

    PubMed

    Lu, Guozhong; Ling, Kai; Zhao, Peng; Xu, Zhenghong; Deng, Cao; Zheng, Hua; Huang, Jin; Chen, Jinghua

    2010-01-01

    In situ photopolymerized hydrogel dressings create minimally invasive methods that offer advantages over the use of preformed dressings such as conformability in any wound bed, convenience of application, and improved patient compliance and comfort. Here, we report an in situ-formed hydrogel membrane through ultraviolet cross-linking of a photocross-linkable azidobenzoic hydroxypropyl chitosan aqueous solution. The hydrogel membrane is stable, flexible, and transparent, with a bulk network structure of smoothness, integrity, and density. Fluid uptake ability, water vapor transmission rate, water retention, and bioadhesion of the thus resulted hydrogel membranes (0.1 mm thick) were determined to range from 97.0-96.3%, 2,934-2,561 g/m(2)/day, 36.69-22.94% (after 6 days), and 4.8-12.3 N/cm(2), respectively. These data indicate that the hydrogel membrane can maintain a long period of moist environment over the wound bed for enhancing reepithelialization. Specifically, these properties of the hydrogel membrane were controllable to some extent, by adjusting the substitution degree of the photoreactive azide groups. The hydrogel membrane also exhibited barrier function, as it was impermeable to bacteria but permeable to oxygen. In vitro experiments using two major skin cell types (dermal fibroblast and epidermal keratinocyte) revealed the hydrogel membrane have neither cytotoxicity nor an effect on cell proliferation. Taken together, the in situ photocross-linked azidobenzoic hydroxypropyl chitosan hydrogel membrane has a great potential in the management of wound healing and skin burn.

  6. A novel in situ-formed hydrogel wound dressing by the photocross-linking of a chitosan derivative.

    PubMed

    Lu, Guozhong; Ling, Kai; Zhao, Peng; Xu, Zhenghong; Deng, Cao; Zheng, Hua; Huang, Jin; Chen, Jinghua

    2010-01-01

    In situ photopolymerized hydrogel dressings create minimally invasive methods that offer advantages over the use of preformed dressings such as conformability in any wound bed, convenience of application, and improved patient compliance and comfort. Here, we report an in situ-formed hydrogel membrane through ultraviolet cross-linking of a photocross-linkable azidobenzoic hydroxypropyl chitosan aqueous solution. The hydrogel membrane is stable, flexible, and transparent, with a bulk network structure of smoothness, integrity, and density. Fluid uptake ability, water vapor transmission rate, water retention, and bioadhesion of the thus resulted hydrogel membranes (0.1 mm thick) were determined to range from 97.0-96.3%, 2,934-2,561 g/m(2)/day, 36.69-22.94% (after 6 days), and 4.8-12.3 N/cm(2), respectively. These data indicate that the hydrogel membrane can maintain a long period of moist environment over the wound bed for enhancing reepithelialization. Specifically, these properties of the hydrogel membrane were controllable to some extent, by adjusting the substitution degree of the photoreactive azide groups. The hydrogel membrane also exhibited barrier function, as it was impermeable to bacteria but permeable to oxygen. In vitro experiments using two major skin cell types (dermal fibroblast and epidermal keratinocyte) revealed the hydrogel membrane have neither cytotoxicity nor an effect on cell proliferation. Taken together, the in situ photocross-linked azidobenzoic hydroxypropyl chitosan hydrogel membrane has a great potential in the management of wound healing and skin burn. PMID:20082682

  7. Competition between a Lawn-Forming Cynodon dactylon and a Tufted Grass Species Hyparrhenia hirta on a South-African Dystrophic Savanna

    PubMed Central

    Zwerts, J. A.; Prins, H. H. T.; Bomhoff, D.; Verhagen, I.; Swart, J. M.; de Boer, W. F.

    2015-01-01

    South African savanna grasslands are often characterised by indigestible tufted grass species whereas lawn grasses are far more desirable in terms of herbivore sustenance. We aimed to investigate the role of nutrients and/or the disturbance (grazing, trampling) by herbivores on the formation of grazing lawns. We conducted a series of common garden experiments to test the effect of nutrients on interspecific competition between a typical lawn-forming grass species (Cynodon dactylon) and a species that is frequently found outside grazing lawns (Hyparrhenia hirta), and tested for the effect of herbivore disturbance in the form of trampling and clipping. We also performed a vegetation and herbivore survey to apply experimentally derived insights to field observations. Our results showed that interspecific competition was not affected by soil nutrient concentrations. C. dactylon did show much more resilience to disturbance than H. hirta, presumably due to the regenerative capacity of its rhizomes. Results from the field survey were in line with these findings, describing a correlation between herbivore pressure and C. dactylon abundance. We conclude that herbivore disturbance, and not soil nutrients, provide C. dactylon with a competitive advantage over H. hirta, due to vegetative regeneration from its rhizomes. This provides evidence for the importance of concentrated, high herbivore densities for the creation and maintenance of grazing lawns. PMID:26510157

  8. Competition between a Lawn-Forming Cynodon dactylon and a Tufted Grass Species Hyparrhenia hirta on a South-African Dystrophic Savanna.

    PubMed

    Zwerts, J A; Prins, H H T; Bomhoff, D; Verhagen, I; Swart, J M; de Boer, W F

    2015-01-01

    South African savanna grasslands are often characterised by indigestible tufted grass species whereas lawn grasses are far more desirable in terms of herbivore sustenance. We aimed to investigate the role of nutrients and/or the disturbance (grazing, trampling) by herbivores on the formation of grazing lawns. We conducted a series of common garden experiments to test the effect of nutrients on interspecific competition between a typical lawn-forming grass species (Cynodon dactylon) and a species that is frequently found outside grazing lawns (Hyparrhenia hirta), and tested for the effect of herbivore disturbance in the form of trampling and clipping. We also performed a vegetation and herbivore survey to apply experimentally derived insights to field observations. Our results showed that interspecific competition was not affected by soil nutrient concentrations. C. dactylon did show much more resilience to disturbance than H. hirta, presumably due to the regenerative capacity of its rhizomes. Results from the field survey were in line with these findings, describing a correlation between herbivore pressure and C. dactylon abundance. We conclude that herbivore disturbance, and not soil nutrients, provide C. dactylon with a competitive advantage over H. hirta, due to vegetative regeneration from its rhizomes. This provides evidence for the importance of concentrated, high herbivore densities for the creation and maintenance of grazing lawns. PMID:26510157

  9. Positive and negative effects of habitat-forming algae on survival, growth and intra-specific competition of limpets.

    PubMed

    Marzinelli, Ezequiel M; Burrows, Michael T; Jackson, Angus C; Mayer-Pinto, Mariana

    2012-01-01

    Understanding the effects of environmental change on the distribution and abundance of strongly interacting organisms, such as intertidal macroalgae and their grazers, needs a thorough knowledge of their underpinning ecological relationships. Control of grazer-plant interactions is bi-directional on northwestern European coasts: grazing by limpets structures populations of macroalgae, while macroalgae provide habitat and food for limpets. Scottish shores dominated by the macroalga Fucus vesiculosus support lower densities and larger sizes of limpets Patella vulgata than shores with less Fucus. These patterns may be due to differences in inter-size-class competitive interactions of limpets among shores with different covers of Fucus. To examine this model, densities of small and large limpets were manipulated in plots with and without Fucus. Amounts of biofilm were measured in each plot. The presence of Fucus increased survival but hindered growth of small (15 mm TL) limpets, which were negatively affected by the presence of large limpets (31 mm TL). In contrast, large limpets were not affected by the presence of Fucus or of small limpets. This suggests the occurrence of asymmetric inter-size-class competition, which was influenced by the presence of macroalgae. Macroalgae and increased densities of limpets did not influence amounts of biofilm. Our findings highlight the role of interactions among organisms in generating ecological responses to environmental change.

  10. Production of a baculovirus-derived gp50 protein and utilization in a competitive enzyme-linked immunosorbent assay for the serodiagnosis of pseudorabies virus.

    PubMed Central

    Prud'homme, I; Zhou, E M; Traykova, M; Trotter, H; Chan, M; Afshar, A; Harding, M J

    1997-01-01

    The pseudorabies virus (PRV) gp50 envelope glycoprotein gene was cloned and expressed in a recombinant baculovirus. An anti-gp50 Mab (1842) recognized a protein of approximately 40 kDa in immunoblotting assays from infected insect cell lysates, while this product was not present in cells infected with wild-type baculovirus. The recombinant protein was purified by lectin affinity chromatography, utilizing lectins specific for O-linked oligosaccharides (Artocarpus integrifolia and Glycine max). Competitive (c) ELISAs, using either crude or lectin-purified antigen, were devised for the detection of antibodies to PRV in sera, and were capable of monitoring sero-conversion by day 14 post-infection. Furthermore, a specificity of 100% and sensitivity of 98% (crude lysate antigen) or 96% (lectin-purified antigen) was found for a panel of 80 swine sera, using the cELISA, as compared to a serum neutralization (SN) test. These studies demonstrated that recombinant PRV gp50 protein shows promise as a cELISA antigen, for serodetection of PRV. Images Figure 2. Figure 3. Figure 4. PMID:9342453

  11. Development and field application of a competitive enzyme-linked immunosorbent assay for detection of Newcastle disease virus antibodies in chickens and ducks.

    PubMed

    Phan, L V; Park, M-J; Kye, S-J; Kim, J-Y; Lee, H-S; Choi, K-S

    2013-08-01

    A competitive enzyme-linked immunosorbent assay (C-ELISA) using a baculovirus-expressed recombinant nucleocapsid protein antigen (rNDV-N) and an rNDV-N-specific monoclonal antibody (5B3) was developed for the detection of Newcastle disease virus (NDV) antibodies, and its diagnostic performance was evaluated. The specificity and sensitivity of the C-ELISA was found to be 98.4 and 98.9%, respectively, for chickens, and 98.2 and 97.9% for ducks. However, the C-ELISA showed weak cross-reaction with hyperimmune antisera to some other avian paramyxovirus serotypes. In all experimentally vaccinated chickens, seroconversion rates at 7 d postinoculation were 100 and 40% when measured by C-ELISA and hemagglutination inhibition (HI), respectively. In field trials, the C-ELISA showed positive results in 98.9% of HI-positive sera and 40.8% of HI-negative sera from NDV-vaccinated chickens (n = 705). In domestic ducks (n = 158) from NDV-positive duck farms (n = 8), the positive rates according to C-ELISA were significantly higher than those according to the HI test. At the same time, 98.1% of ducks (n = 209) from NDV-negative duck farms (n = 11) were also negative by C-ELISA. Our results indicate that C-ELISA could be a useful alternative to HI testing for detecting NDV antibodies in different avian species such as chickens and ducks.

  12. Development and validation of an indirect competitive enzyme-linked immunosorbent assay for monitoring organoarsenic compounds in edible chicken and pork and feed.

    PubMed

    Peng, Dapeng; Feng, Liang; Pan, Yuanhu; Wang, Yulian; Chen, Dongmei; Wang, Juan; Yuan, Zonghui

    2016-04-15

    For the first time in this study, we used molecular modelling to design a suitable hapten (arsanilic acid, ASA) and produced a broad-specificity monoclonal antibody (mAb). This mAb exhibited the IC50 for ASA was 913.7 μg L(-1) and showed the cross-reactivity to ASA (100%), carbarsone (849.2%), and nitarsone (1159.5%), respectively. Based on this mAb, an optimised indirect competitive enzyme linked immunosorbent assay (ic-ELISA) protocol was developed to monitor organoarsenic compounds (OAs) in edible chicken and pork and feed, which the detection limit for OAs in a muscle matrix ranged from 74.2 μg kg(-1) to 143.3 μg kg(-1) and in a feed matrix ranged from 7.4 mg kg(-1) to 11.8 mg kg(-1), the recoveries were 61.3-109.6% with a coefficient of variation of less than 10.8%. These data demonstrated that the developed ic-ELISA is a reliable and useful tool for screening OAs in edible chicken and pork and feed.

  13. Structural Basis of Competition Between PINCH1 and PINCH2 for Binding to the Ankyrin Repeat Domain of Integrin-linked Kinase

    SciTech Connect

    Chiswell, B.; Steigler, A; Razinia, Z; Nalibotski, E; Boggon, T; Calderwood, D

    2010-01-01

    Formation of a heterotrimeric IPP complex composed of integrin-linked kinase (ILK), the LIM domain protein PINCH, and parvin is important for signaling through integrin adhesion receptors. Mammals possess two PINCH genes that are expressed simultaneously in many tissues. PINCH1 and PINCH2 have overlapping functions and can compensate for one another in many settings; however, isoform-specific functions have been reported and it is proposed that association with a PINCH1- or PINCH2-containing IPP complex may provide a bifurcation point in integrin signaling promoting different cellular responses. Here we report that the LIM1 domains of PINCH1 and PINCH2 directly compete for the same binding site on the ankyrin repeat domain (ARD) of ILK. We determined the 1.9 {angstrom} crystal structure of the PINCH2 LIM1 domain complexed with the ARD of ILK, and show that disruption of this interface by point mutagenesis reduces binding in vitro and alters localization of PINCH2 in cells. These studies provide further evidence for the role of the PINCH LIM1 domain in association with ILK and highlight direct competition as one mechanism for regulating which PINCH isoform predominates in IPP complexes. Differential regulation of PINCH1 and PINCH2 expression may therefore provide a means for altering cellular integrin signaling pathways.

  14. Monoclonal antibody production and indirect competitive enzyme-linked immunosorbent assay development of 3-methyl-quinoxaline-2-carboxylic acid based on novel haptens.

    PubMed

    Li, Guopeng; Zhao, Liang; Zhou, Feng; Li, Jiaying; Xing, Yuan; Wang, Tiangang; Zhou, Xilong; Ji, Baoping; Ren, Wanpeng

    2016-10-15

    Two novel immunizing haptens of 3-methyl-quinoxaline-2-carboxylic acid (MQCA) were synthesized and conjugated with cationized bovine serum albumin. Female BALB/c mice were immunized with above conjugates, splenocytes were fused with Sp2/0 cells to produce monoclonal antibody. Compared with previous studies, antibodies raised in this work showed higher sensitivity. Meantime, a novel heterologous coating hapten was also prepared. The indirect competitive enzyme-linked immunosorbent assay (icELISA) based on the optimum condition showed an IC50 of 3.1μg/kg (ppb), and the linear range of 0.46-10.5ppb for MQCA. The limit of detect (LOD) of MQCA in swine muscle, swine liver and chicken was 0.32, 0.54, and 0.28ppb, respectively. The LOD of this assay can satisfy the minimum required performance levels (4ppb) for MQCA. These results indicated that the proposed ELISA, with high sensitivity and specificity, as well as good reproducibility and accuracy, is suitable for determination of MQCA residues in food samples.

  15. Development and validation of an indirect competitive enzyme-linked immunosorbent assay for monitoring organoarsenic compounds in edible chicken and pork and feed.

    PubMed

    Peng, Dapeng; Feng, Liang; Pan, Yuanhu; Wang, Yulian; Chen, Dongmei; Wang, Juan; Yuan, Zonghui

    2016-04-15

    For the first time in this study, we used molecular modelling to design a suitable hapten (arsanilic acid, ASA) and produced a broad-specificity monoclonal antibody (mAb). This mAb exhibited the IC50 for ASA was 913.7 μg L(-1) and showed the cross-reactivity to ASA (100%), carbarsone (849.2%), and nitarsone (1159.5%), respectively. Based on this mAb, an optimised indirect competitive enzyme linked immunosorbent assay (ic-ELISA) protocol was developed to monitor organoarsenic compounds (OAs) in edible chicken and pork and feed, which the detection limit for OAs in a muscle matrix ranged from 74.2 μg kg(-1) to 143.3 μg kg(-1) and in a feed matrix ranged from 7.4 mg kg(-1) to 11.8 mg kg(-1), the recoveries were 61.3-109.6% with a coefficient of variation of less than 10.8%. These data demonstrated that the developed ic-ELISA is a reliable and useful tool for screening OAs in edible chicken and pork and feed. PMID:26617022

  16. Development and evaluation of a competitive enzyme-linked immunosorbent assay using a monoclonal antibody for diagnosis of severe fever with thrombocytopenia syndrome virus in bovine sera

    PubMed Central

    Lee, Hyojin; Kim, Eun-Ju; Song, Jae-Young; Choi, Jeong Soo; Lee, Ji Youn; Cho, In-Soo

    2016-01-01

    Severe fever with thrombocytopenia syndrome (SFTS) caused by the SFTS virus (SFTSV), a phlebovirus in the family Bunyaviridae, is an emerging tick-borne infectious disease that impacts humans. This disease manifests as a decreased blood cell count and multi-organ failure, with a case-fatality rate of more than 12% in China. Because vaccines or antiviral drugs for the treatment of this disease are not available, monitoring the SFTS circulation in animals and controlling the tick-mammal cycle are important for preventing SFTS. Monoclonal antibodies against the recombinant nucleoprotein of SFTSV were generated to develop a competitive enzyme-linked immunosorbent assay (cELISA) for the detection of antibodies against SFTSV infection in cattle. The specificity and sensitivity of cELISA was assessed by comparing the results of this assay to those of an immunofluorescence assay (IFA). The results of the cELISA using 416 field bovine serum samples and laboratory-immunized positive sera showed 98.1% consistency with those of the IFA. The cELISA used in this study did not show cross-reactivity with antisera against other viral cattle diseases. The cELISA presented in this study can be applied to detect antibodies against SFTSV in cattle. PMID:26435543

  17. Production of a baculovirus-derived gp50 protein and utilization in a competitive enzyme-linked immunosorbent assay for the serodiagnosis of pseudorabies virus.

    PubMed

    Prud'homme, I; Zhou, E M; Traykova, M; Trotter, H; Chan, M; Afshar, A; Harding, M J

    1997-10-01

    The pseudorabies virus (PRV) gp50 envelope glycoprotein gene was cloned and expressed in a recombinant baculovirus. An anti-gp50 Mab (1842) recognized a protein of approximately 40 kDa in immunoblotting assays from infected insect cell lysates, while this product was not present in cells infected with wild-type baculovirus. The recombinant protein was purified by lectin affinity chromatography, utilizing lectins specific for O-linked oligosaccharides (Artocarpus integrifolia and Glycine max). Competitive (c) ELISAs, using either crude or lectin-purified antigen, were devised for the detection of antibodies to PRV in sera, and were capable of monitoring sero-conversion by day 14 post-infection. Furthermore, a specificity of 100% and sensitivity of 98% (crude lysate antigen) or 96% (lectin-purified antigen) was found for a panel of 80 swine sera, using the cELISA, as compared to a serum neutralization (SN) test. These studies demonstrated that recombinant PRV gp50 protein shows promise as a cELISA antigen, for serodetection of PRV.

  18. Development, validation, and utilization of a competitive enzyme-linked immunosorbent assay for the detection of antibodies against Brucella species in marine mammals.

    PubMed

    Meegan, Jenny; Field, Cara; Sidor, Inga; Romano, Tracy; Casinghino, Sandra; Smith, Cynthia R; Kashinsky, Lizabeth; Fair, Patricia A; Bossart, Gregory; Wells, Randall; Dunn, J Lawrence

    2010-11-01

    A competitive enzyme-linked immunosorbent assay (cELISA) was developed by using a whole-cell antigen from a marine Brucella sp. isolated from a harbor seal (Phoca vitulina). The assay was designed to screen sera from multiple marine mammal species for the presence of antibodies against marine-origin Brucella. Based on comparisons with culture-confirmed cases, specificity and sensitivity for cetacean samples tested were 73% and 100%, respectively. For pinniped samples, specificity and sensitivity values were 77% and 67%, respectively. Hawaiian monk seal (Monachus schauinslandi; n  =  28) and bottlenose dolphin (Tursiops truncatus; n  =  48) serum samples were tested, and the results were compared with several other assays designed to detect Brucella abortus antibodies. The comparison testing revealed the marine-origin cELISA to be more sensitive than the B. abortus tests by the detection of additional positive serum samples. The newly developed cELISA is an effective serologic method for detection of the presence of antibodies against marine-origin Brucella sp. in marine mammals. PMID:21088168

  19. Competitive morality.

    PubMed

    Roberts, Gilbert

    2013-02-01

    Baumard et al. argue that partner choice leads to fairness and mutualism, which then form the basis for morality. I comment that mutualism takes us only so far, and I apply the theory of competitive altruism in arguing how strategic investment in behaviours which make one a desirable partner may drive moral conduct.

  20. Mixing, entropy and competition

    NASA Astrophysics Data System (ADS)

    Klimenko, A. Y.

    2012-06-01

    Non-traditional thermodynamics, applied to random behaviour associated with turbulence, mixing and competition, is reviewed and analysed. Competitive mixing represents a general framework for the study of generic properties of competitive systems and can be used to model a wide class of non-equilibrium phenomena ranging from turbulent premixed flames and invasion waves to complex competitive systems. We demonstrate consistency of the general principles of competition with thermodynamic description, review and analyse the related entropy concepts and introduce the corresponding competitive H-theorem. A competitive system can be characterized by a thermodynamic quantity—competitive potential—which determines the likely direction of evolution of the system. Contested resources tend to move between systems from lower to higher values of the competitive potential. There is, however, an important difference between conventional thermodynamics and competitive thermodynamics. While conventional thermodynamics is constrained by its zeroth law and is fundamentally transitive, the transitivity of competitive thermodynamics depends on the transitivity of the competition rules. Intransitivities are common in the real world and are responsible for complex behaviour in competitive systems. This work follows ideas and methods that have originated from the analysis of turbulent combustion, but reviews a much broader scope of issues linked to mixing and competition, including thermodynamic characterization of complex competitive systems with self-organization. The approach presented here is interdisciplinary and is addressed to the general educated readers, whereas the mathematical details can be found in the appendices.

  1. Evolution of leaf-form in land plants linked to atmospheric CO2 decline in the Late Palaeozoic era.

    PubMed

    Beerling, D J; Osborne, C P; Chaloner, W G

    2001-03-15

    The widespread appearance of megaphyll leaves, with their branched veins and planate form, did not occur until the close of the Devonian period at about 360 Myr ago. This happened about 40 Myr after simple leafless vascular plants first colonized the land in the Late Silurian/Early Devonian, but the reason for the slow emergence of this common feature of present-day plants is presently unresolved. Here we show, in a series of quantitative analyses using fossil leaf characters and biophysical principles, that the delay was causally linked with a 90% drop in atmospheric pCO2 during the Late Palaeozoic era. In contrast to simulations for a typical Early Devonian land plant, possessing few stomata on leafless stems, those for a planate leaf with the same stomatal characteristics indicate that it would have suffered lethal overheating, because of greater interception of solar energy and low transpiration. When planate leaves first appeared in the Late Devonian and subsequently diversified in the Carboniferous period, they possessed substantially higher stomatal densities. This observation is consistent with the effects of the pCO2 on stomatal development and suggests that the evolution of planate leaves could only have occurred after an increase in stomatal density, allowing higher transpiration rates that were sufficient to maintain cool and viable leaf temperatures.

  2. Chemical and structural characterization of interstrand cross-links formed between abasic sites and adenine residues in duplex DNA

    PubMed Central

    Price, Nathan E.; Catalano, Michael J.; Liu, Shuo; Wang, Yinsheng; Gates, Kent S.

    2015-01-01

    A new type of interstrand DNA–DNA cross-link between abasic (Ap) sites and 2′-deoxyadenosine (dA) residues was recently reported, but the chemical structure and properties of this lesion were not rigorously established. Here we characterized the nucleoside cross-link remnant released by enzymatic digestion of duplex DNA containing the dA-Ap cross-link. A synthetic standard was prepared for the putative nucleoside cross-link remnant 6 in which the anomeric carbon of the 2-deoxyribose residue was connected to the exocyclic N6-amino group of dA. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis showed that the synthetic material 6 matched the authentic cross-link remnant released by enzymatic digestion of cross-linked DNA. These findings establish the chemical structure of the dA-Ap cross-link released from duplex DNA and may provide methods for the detection of this lesion in cellular DNA. Both the nucleoside cross-link remnant 6 and the cross-link in duplex DNA were quite stable at pH 7 and 37°C, suggesting that the dA-Ap cross-link could be a persistent lesion with the potential to block the action of various DNA processing enzymes. PMID:25779045

  3. Enhanced sensitivity of an antibody competitive blocking enzyme-linked immunosorbent assay using Equine arteritis virus purified by anion-exchange membrane chromatography.

    PubMed

    Chung, Chungwon J; Grimm, Amanda L; Wilson, Carey L; Balasuriya, Udeni B R; Chung, Grace; Timoney, Peter J; Bandaranayaka-Mudiyanselage, Chandima-Bandara; Lee, Stephen S; McGuire, Travis C

    2015-11-01

    In an effort to improve a competitive blocking enzyme-linked immunosorbent assay (cELISA) for antibody detection to Equine arteritis virus (EAV), antigen purified by anion-exchange membrane chromatography capsule (AEC) was evaluated. Virus purification by the AEC method was rapid and easily scalable. A comparison was made between virus purified by the AEC method with that obtained by differential centrifugation based on the following: 1) the relative purity and quality of EAV glycoprotein 5 (GP5) containing the epitope defined by monoclonal antibody 17B7, and 2) the relative sensitivity of a commercial antibody cELISA with the only change being the 2 purified antigens. On evaluation by Western blot using GP5-specific monoclonal antibody 17B7, the AEC-purified EAV contained 86% GP5 monomer whereas the differentially centrifuged EAV contained <29% of the monomer. Improvement of analytical sensitivity without sacrifice of analytical specificity was clearly evident when cELISAs prepared with EAV antigen by each purification method were evaluated using 7 sensitivity and specificity check sets. Furthermore, the AEC-purified EAV-based cELISA had 30-40% higher agreement with the virus neutralization (VN) test than the cELISA prepared with differentially centrifuged EAV based on testing 40 borderline EAV-seropositive samples as defined by the VN test. In addition, the AEC-purified cELISA had highly significant (P = 0.001) robustness indicated by intra-laboratory repeatability and interlaboratory reproducibility when evaluated with the sensitivity check sets. Thus, use of AEC-purified EAV in the cELISA should lead to closer harmonization of the cELISA with the World Organization for Animal Health-prescribed VN test.

  4. Development of a competitive enzyme-linked immunosorbent assay for detection of antibodies against the 3B protein of foot-and-mouth disease virus.

    PubMed

    Yang, Ming; Parida, Satya; Salo, Tim; Hole, Kate; Velazquez-Salinas, Lauro; Clavijo, Alfonso

    2015-04-01

    Foot-and-mouth disease (FMD) is one of the most highly contagious and economically devastating diseases, and it severely constrains the international trade of animals. Vaccination against FMD is a key element in the control of FMD. However, vaccination of susceptible animals raises critical issues, such as the differentiation of infected animals from vaccinated animals. The current study developed a reliable and rapid test to detect antibodies against the conserved, nonstructural proteins (NSPs) of the FMD virus (FMDV) to distinguish infected animals from vaccinated animals. A monoclonal antibody (MAb) against the FMDV NSP 3B was produced. A competitive enzyme-linked immunosorbent assay (cELISA) for FMDV/NSP antibody detection was developed using a recombinant 3ABC protein as the antigen and the 3B-specific MAb. Sera collected from naive, FMDV experimentally infected, vaccinated carrier, and noncarrier animals were tested using the 3B cELISA. The diagnostic specificity was 99.4% for naive animals (cattle, pigs, and sheep) and 99.7% for vaccinated noncarrier animals. The diagnostic sensitivity was 100% for experimentally inoculated animals and 64% for vaccinated carrier animals. The performance of this 3B cELISA was compared to that of four commercial ELISA kits using a panel of serum samples established by the World Reference Laboratory for FMD at The Pirbright Institute, Pirbright, United Kingdom. The diagnostic sensitivity of the 3B cELISA for the panel of FMDV/NSP-positive bovine serum samples was 94%, which was comparable to or better than that of the commercially available NSP antibody detection kits. This 3B cELISA is a simple, reliable test to detect antibodies against FMDV nonstructural proteins.

  5. Development of a Competitive Enzyme-Linked Immunosorbent Assay for Detection of Antibodies against the 3B Protein of Foot-and-Mouth Disease Virus

    PubMed Central

    Yang, Ming; Parida, Satya; Salo, Tim; Hole, Kate; Velazquez-Salinas, Lauro

    2015-01-01

    Foot-and-mouth disease (FMD) is one of the most highly contagious and economically devastating diseases, and it severely constrains the international trade of animals. Vaccination against FMD is a key element in the control of FMD. However, vaccination of susceptible animals raises critical issues, such as the differentiation of infected animals from vaccinated animals. The current study developed a reliable and rapid test to detect antibodies against the conserved, nonstructural proteins (NSPs) of the FMD virus (FMDV) to distinguish infected animals from vaccinated animals. A monoclonal antibody (MAb) against the FMDV NSP 3B was produced. A competitive enzyme-linked immunosorbent assay (cELISA) for FMDV/NSP antibody detection was developed using a recombinant 3ABC protein as the antigen and the 3B-specific MAb. Sera collected from naive, FMDV experimentally infected, vaccinated carrier, and noncarrier animals were tested using the 3B cELISA. The diagnostic specificity was 99.4% for naive animals (cattle, pigs, and sheep) and 99.7% for vaccinated noncarrier animals. The diagnostic sensitivity was 100% for experimentally inoculated animals and 64% for vaccinated carrier animals. The performance of this 3B cELISA was compared to that of four commercial ELISA kits using a panel of serum samples established by the World Reference Laboratory for FMD at The Pirbright Institute, Pirbright, United Kingdom. The diagnostic sensitivity of the 3B cELISA for the panel of FMDV/NSP-positive bovine serum samples was 94%, which was comparable to or better than that of the commercially available NSP antibody detection kits. This 3B cELISA is a simple, reliable test to detect antibodies against FMDV nonstructural proteins. PMID:25651918

  6. Development and validation of an indirect competitive enzyme-linked immunosorbent assay for the screening of tylosin and tilmicosin in muscle, liver, milk, honey and eggs.

    PubMed

    Peng, Dapeng; Ye, Shengqiang; Wang, Yulian; Chen, Dongmei; Tao, Yanfei; Huang, Lingli; Liu, Zhenli; Dai, Menghong; Wang, Xiaoqing; Yuan, Zonghui

    2012-01-11

    Incorrect use of tylosin and tilmicosin could result in allergy and select resistance. To monitor the illegal use of these antibiotics in animals, a monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) has been established. Several haptens were synthesized and conjugated to carrier protein. Female Balb/c mice were inoculated with the four different conjugates to produce monoclonal antibodies according to the schemes of immunization. Aftercell fusion and culture several times, nine hybridoma cell lines were isolated. Only one, 3C4 that has isotype IgG2a, was selected for detailed study. The cross-reactivity of the monoclonal antibody 3C4 to tylosin and tilmicosin was 100% and 51% respectively. The standard curves based on the tylosin and tilmicosin matrix calibration ranged from 2.5 to 40 μg L(-1), with an IC(50) value of 6.1 μg L(-1) and 12.1 μg L(-1), respectively. The limits of detection of the ic-ELISA ranged from 5.1 μg kg(-1) to 13.8 μg kg(-1) in edible animal tissues. The recoveries were 74.1% to 120.7% with less than 18.6% of the coefficient of variation when tylosin and tilmicosin were spiked in various biological matrices with the concentrations of 25.0-200.0 μg kg(-1). Good correlations between the results of the ic-ELISA and high performance liquid chromatography were observed in the incurred tissues. These results suggest that the ic-ELISA is a sensitive, accurate and low-cost method that would be a useful tool for the screening of the residues of tylosin and tilmicosin in muscle, liver, milk, honey and eggs.

  7. Pollen competition among two species of Senecio (Asteraceae) that form a hybrid zone on Mt. Etna, Sicily.

    PubMed

    Chapman, Mark A; Forbes, David G; Abbott, Richard J

    2005-04-01

    Hybridization between interfertile, sympatric or parapatric, plant species can be reduced significantly by conspecific pollen advantage (CPA), whereby conspecific pollen has an advantage over heterospecific pollen in terms of ovule fertilization. We examined CPA in two interfertile species of Senecio, S. aethnensis, and S. chrysanthemifolius (Asteraceae), which form a hybrid zone on Mt. Etna, Sicily. Individuals of both species were pollinated with pollen mixtures containing 0, 25, 50, 75, or 100% heterospecific pollen, and offspring were genotyped to determine if they were products of conspecific or heterospecific pollen fertilizing the ovules. The mean proportion of hybrid offspring produced on S. aethnensis plants was not significantly different to that expected based on the proportion of heterospecific pollen applied to the flower head. However, S. chrysanthemifolius mother plants showed moderate CPA, with the proportion of hybrid offspring significantly less than expected. Seed set or seed germination was not reduced, hence the CPA found for S. chrysanthemifolius acts before ovule fertilization. The consequences of asymmetry in CPA on the reproductive isolation of S. aethnensis are briefly discussed, along with other mechanisms that may play a role in the maintenance of the hybrid zone on Mt. Etna.

  8. Competitive binding inhibition enzyme-linked immunosorbent assay that uses the secreted aspartyl proteinase of Candida albicans as an antigenic marker for diagnosis of disseminated candidiasis.

    PubMed

    Morrison, Christine J; Hurst, Steven F; Reiss, Errol

    2003-09-01

    The secreted aspartyl proteinases (Saps) of Candida albicans have been implicated as virulence factors associated with adherence and tissue invasion. The potential use of proteinases as markers of invasive candidiasis led us to develop a competitive binding inhibition enzyme-linked immunosorbent assay (ELISA) to detect Sap in clinical specimens. Daily serum and urine specimens were collected from rabbits that had been immunosuppressed with cyclophosphamide and cortisone acetate and infected intravenously with 10(7) C. albicans blastoconidia. Disseminated infection was confirmed by organ culture and histopathology. Although ELISA inhibition was observed when serum specimens from these rabbits were used, more significant inhibition, which correlated with disease progression, occurred when urine specimens were used. Urine collected as early as 1 day after infection resulted in significant ELISA inhibition (mean inhibition +/- standard error [SE] compared with preinfection control urine, 15.7% +/- 2.7% [P < 0.01]), and inhibition increased on days 2 through 5 (29.4% +/- 4.8% to 44.5% +/- 3.5% [P < 0.001]). Urine specimens from immunosuppressed rabbits infected intravenously with Candida tropicalis, Candida parapsilosis, Candida krusei, Cryptococcus neoformans, Aspergillus fumigatus, or Staphylococcus aureus were negative in the assay despite culture-proven dissemination. Nonimmunosuppressed rabbits receiving oral tetracycline and gentamicin treatment were given 2 x 10(8) C. albicans blastoconidia orally or intraurethrally to establish colonization of the gastrointestinal tract or bladder, respectively, without systemic dissemination; urine specimens from these rabbits also gave negative ELISA results. Dissemination to the kidney and spleen occurred in one rabbit challenged by intragastric inoculation, and urine from this rabbit demonstrated significant inhibition in the ELISA (mean inhibition +/- SE by day 3 after infection, 32.9% +/- 2.7% [P < 0.001]). The overall

  9. Cultural and Gender Differences in the Implications of Competition for Early Adolescent Friendship

    ERIC Educational Resources Information Center

    Schneider, Barry H.; Woodburn, Sharon; del Pilar Soteras del Toro, Maria; Udvari, Stephen J.

    2005-01-01

    Harry Stack Sullivan maintained that competition between friends in early adolescence would generally destroy their friendship. Working with early adolescent samples in Canada, Costa Rica, and Cuba, we found that hypercompetitiveness--a form of competition involving the need to prove one?s own superiority--was linked with conflict between friends,…

  10. Linking Organisational Training and Development Practices with New Forms of Career Structure: A Cross-National Exploration.

    ERIC Educational Resources Information Center

    Kelly, Aidan; Brannick, Teresa; Hulpke, John; Levine, Jacqueline; To, Michelle

    2003-01-01

    Human resource management data were collected from 149 Irish, 201 Hong Kong, 92 Singaporean, and 144 Chinese organizations. Career patterns and training practices showed distinct differences. Irish organizations were more likely to have lower levels of career paths; their training practices suggested more new forms of careers. Fewer paths indicate…

  11. Use of Activated Carbon in Packaging to Attenuate Formaldehyde-Induced and Formic Acid-Induced Degradation and Reduce Gelatin Cross-Linking in Solid Dosage Forms.

    PubMed

    Colgan, Stephen T; Zelesky, Todd C; Chen, Raymond; Likar, Michael D; MacDonald, Bruce C; Hawkins, Joel M; Carroll, Sophia C; Johnson, Gail M; Space, J Sean; Jensen, James F; DeMatteo, Vincent A

    2016-07-01

    Formaldehyde and formic acid are reactive impurities found in commonly used excipients and can be responsible for limiting drug product shelf-life. Described here is the use of activated carbon in drug product packaging to attenuate formaldehyde-induced and formic acid-induced drug degradation in tablets and cross-linking in hard gelatin capsules. Several pharmaceutical products with known or potential vulnerabilities to formaldehyde-induced or formic acid-induced degradation or gelatin cross-linking were subjected to accelerated stability challenges in the presence and absence of activated carbon. The effects of time and storage conditions were determined. For all of the products studied, activated carbon attenuated drug degradation or gelatin cross-linking. This novel use of activated carbon in pharmaceutical packaging may be useful for enhancing the chemical stability of drug products or the dissolution stability of gelatin-containing dosage forms and may allow for the 1) extension of a drug product's shelf-life when the limiting attribute is a degradation product induced by a reactive impurity, 2) marketing of a drug product in hotter and more humid climatic zones than currently supported without the use of activated carbon, and 3) enhanced dissolution stability of products that are vulnerable to gelatin cross-linking.

  12. EDITORIAL: Physics competitions Physics competitions

    NASA Astrophysics Data System (ADS)

    Jordens, H.; Mathelitsch, L.

    2011-07-01

    International tests on competences, such as TIMSS or PISA, and knowledge of young students have revealed low average scores in many countries, often unexpectedly. One effective measure to increase the average standard of a population is to bring the last third of the group to a higher level. Therefore, many nations put some effort into this activity. This brings the danger that not enough attention is paid to students at the other end, those who are talented. Indeed, it is a very difficult task for a teacher to support the less able and at the same time challenge the gifted students, to lead them to the limits of their abilities and provide for a smooth transition to university study. Physics competitions have been proven to fulfil these last demands to a large degree, and therefore are an important additional and, to some extent, complementary tool for the promotion of talented students. This third special section on physics competitions in European Journal of Physics contains three papers, each dealing with a different form of science contest. The first continues the series of presentations of tasks performed at the International Young Physicists' Tournament, which was held in Vienna in 2011. First place went to the team from Singapore, and they have put their investigation on vertical oscillations of coupled magnets into written form (not required by the tournament, where an oral presentation and a defence and discussion are the central aspects). Their paper shows how rich in physics this problem is, and what level of solutions high-school students can already achieve. Sadly, those responsible for the organization of last year's International Physics Olympiad did not provide us with a report on this competition. This is unfortunate, since the Olympiad in Zagreb was very successful and, in particular, the experimental tasks were creative and demanding. Very similar to the aims and the execution of the Physics Olympiad is the International Olympiad on Astronomy

  13. Genetic forms of nephrogenic diabetes insipidus (NDI): Vasopressin receptor defect (X-linked) and aquaporin defect (autosomal recessive and dominant).

    PubMed

    Bichet, Daniel G; Bockenhauer, Detlef

    2016-03-01

    Nephrogenic diabetes insipidus (NDI), which can be inherited or acquired, is characterized by an inability to concentrate urine despite normal or elevated plasma concentrations of the antidiuretic hormone, arginine vasopressin (AVP). Polyuria with hyposthenuria and polydipsia are the cardinal clinical manifestations of the disease. About 90% of patients with congenital NDI are males with X-linked NDI who have mutations in the vasopressin V2 receptor (AVPR2) gene encoding the vasopressin V2 receptor. In less than 10% of the families studied, congenital NDI has an autosomal recessive or autosomal dominant mode of inheritance with mutations in the aquaporin-2 (AQP2) gene. When studied in vitro, most AVPR2 and AQP2 mutations lead to proteins trapped in the endoplasmic reticulum and are unable to reach the plasma membrane. Prior knowledge of AVPR2 or AQP2 mutations in NDI families and perinatal mutation testing is of direct clinical value and can avert the physical and mental retardation associated with repeated episodes of dehydration.

  14. Genetic forms of nephrogenic diabetes insipidus (NDI): Vasopressin receptor defect (X-linked) and aquaporin defect (autosomal recessive and dominant).

    PubMed

    Bichet, Daniel G; Bockenhauer, Detlef

    2016-03-01

    Nephrogenic diabetes insipidus (NDI), which can be inherited or acquired, is characterized by an inability to concentrate urine despite normal or elevated plasma concentrations of the antidiuretic hormone, arginine vasopressin (AVP). Polyuria with hyposthenuria and polydipsia are the cardinal clinical manifestations of the disease. About 90% of patients with congenital NDI are males with X-linked NDI who have mutations in the vasopressin V2 receptor (AVPR2) gene encoding the vasopressin V2 receptor. In less than 10% of the families studied, congenital NDI has an autosomal recessive or autosomal dominant mode of inheritance with mutations in the aquaporin-2 (AQP2) gene. When studied in vitro, most AVPR2 and AQP2 mutations lead to proteins trapped in the endoplasmic reticulum and are unable to reach the plasma membrane. Prior knowledge of AVPR2 or AQP2 mutations in NDI families and perinatal mutation testing is of direct clinical value and can avert the physical and mental retardation associated with repeated episodes of dehydration. PMID:27156763

  15. Cross-Linking the Fibers of Supramolecular Gels Formed from a Tripodal Terpyridine Derived Ligand with d-Block Metal Ions.

    PubMed

    Kotova, Oxana; Daly, Ronan; dos Santos, Cidália M G; Kruger, Paul E; Boland, John J; Gunnlaugsson, Thorfinnur

    2015-08-17

    The tripodal terpyridine ligand, L, forms 1D helical supramolecular polymers/gels in H2O-CH3OH solution mediated through hydrogen bonding and π-π interactions. These gels further cross-link into 3D supramolecular metallogels with a range of metal ions (M) such as Fe(II), Ni(II), Cu(II), Zn(II), and Ru(III); the cross-linking resulting in the formation of colored or colorless gels. The fibrous morphology of these gels was confirmed using scanning electron microscopy (SEM); while the self-assembly processes between L and M were investigated by absorbance and emission spectroscopy from which their binding constants were determined by using a nonlinear regression analysis. PMID:26222397

  16. Job-Linked Literacy: Innovative Strategies at Work. Part II. Meeting the Challenge of Change: Basic Skills for a Competitive Workforce. A Work in America Policy Study.

    ERIC Educational Resources Information Center

    Rosow, Jerome M.; Zager, Robert

    This volume, Interim Report No. 2 in a 3-year study, establishes the need for job-linked literacy programs that respond to technological and organizational change, outlines the character of successful programs, and demonstrates these programs' potential value. The volume is divided into two parts: report and case studies. The introduction to the…

  17. Mapping of a possible X-linked form of familial developmental dysphasia (FDD) in a single large pedigree

    SciTech Connect

    Dunne, P.W.; Doody, R.S.; Epstein, H.F.

    1994-09-01

    Children diagnosed with developmental dysphasia develop speech very late without exhibiting sensory or motor dysfunction, and when they do begin to speak their grammar is abnormal. A large three-generation British pedigree was recently identified in which 16 out of 30 members were diagnosed as dysphasic. Assuming a dominant mode of inheritance with homogeneous phenotypic expression and complete penetrance among affected members, we showed by simulation analysis that this pedigree has the power to detect linkage to marker loci with an average maximum LOD score of 3.67 at {theta}=0.1. Given the absence of male-to-male transmission and a ratio of female to male affecteds (10/6) in this pedigree within the expected range for an X-linked dominant mode of inheritance, we decided to begin a genome-wide linkage analysis with microsatellite markers on the human X chromosome. Fifteen individuals (10 affected) from three generations were genotyped with 35 polymorphic STS`s (Research Genetics) which were approximately uniformly distributed along the X chromosome. Two-point linkage was assessed using the MLINK and ILINK programs from the LINKAGE package. Markers DXS1223, DXS987, DXS996 and DXS1060 on Xp22 showed consistent linkage to the disease locus with a maximum LOD score of 0.86 at a distance of 22 cM for DXS1060. If further analysis with additional markers and additional family members confirms X-linkage, such a localization would provide support for Lehrke`s hypothesis for X-linkage of major intellectual traits including verbal functioning.

  18. Optical properties and oxidation of carbonized and cross-linked structures formed in polycarbonate by plasma immersion ion implantation

    NASA Astrophysics Data System (ADS)

    Kosobrodova, E.; Kondyurin, A.; Chrzanowski, W.; McCulloch, D. G.; McKenzie, D. R.; Bilek, M. M. M.

    2014-06-01

    At ion fluences higher than 5 · 1015 ions/cm2, plasma immersion ion implantation (PIII) of polycarbonate (PC) results in a formation of a carbonized surface layer. The thickness of this layer is close to the depth of ion penetration. A comparison of PIII treated, spin-coated PC films with pre-treatment thicknesses designed to match and exceed the carbonized layer thickness is employed to study the properties of the carbonised layer independently from the less modified underlying structure. At ion fluencies higher than 1016 ions/cm2, the thinner PC film is completely transformed into an amorphous carbon-like material with no traces of the initial PC structure. The thicker films, however, incorporated two layers: a top carbonised layer and a cross-linked layer below. Compared to the two-layered PC film, the completely carbonized layer was found to have a much higher concentration of Cdbnd O bonds and much lower concentration of O-H bonds after exposure to atmospheric oxygen. The refractive index of the thicker PC films PIII treated with high ion fluencies is close to the refractive index of diamond-like carbon. Anomalous dispersion of the refractive index of the thicker PC films is observed after formation of the carbonised layer. The refractive index of the thinner PC film has normal dispersion at all ion fluences. At ion fluences of 2 · 1016 ions/cm2, both PC films were found to have the same etching rate as polystyrene. Washing in dichloromethane had no effect on the carbonised layer but affected the underlying material in the case of the thicker PC films leading to a wrinkled structure up to ion fluences of 2 · 1016 ions/cm2. At this and higher fluence, areas of an ordered island-like structure were observed.

  19. Virus-based Photo-Responsive Nanowires Formed By Linking Site-Directed Mutagenesis and Chemical Reaction

    NASA Astrophysics Data System (ADS)

    Murugesan, Murali; Abbineni, Gopal; Nimmo, Susan L.; Cao, Binrui; Mao, Chuanbin

    2013-05-01

    Owing to the genetic flexibility and error-free bulk production, bio-nanostructures such as filamentous phage showed great potential in materials synthesis, however, their photo-responsive behaviour is neither explored nor unveiled. Here we show M13 phage genetically engineered with tyrosine residues precisely fused to the major coat protein is converted into a photo-responsive organic nanowire by a site-specific chemical reaction with an aromatic amine to form an azo dye structure on the surface. The resulting azo-M13-phage nanowire exhibits reversible photo-responsive properties due to the photo-switchable cis-trans isomerisation of the azo unit formed on the phage. This result shows that site-specific display of a peptide on bio-nanostructures through site-directed genetic mutagenesis can be translated into site-directed chemical reaction for developing advanced materials. The photo-responsive properties of the azo-M13-phage nanowires may open the door for the development of light controllable smart devices for use in non-linear optics, holography data storage, molecular antenna, and actuators.

  20. Virus-based photo-responsive nanowires formed by linking site-directed mutagenesis and chemical reaction.

    PubMed

    Murugesan, Murali; Abbineni, Gopal; Nimmo, Susan L; Cao, Binrui; Mao, Chuanbin

    2013-01-01

    Owing to the genetic flexibility and error-free bulk production, bio-nanostructures such as filamentous phage showed great potential in materials synthesis, however, their photo-responsive behaviour is neither explored nor unveiled. Here we show M13 phage genetically engineered with tyrosine residues precisely fused to the major coat protein is converted into a photo-responsive organic nanowire by a site-specific chemical reaction with an aromatic amine to form an azo dye structure on the surface. The resulting azo-M13-phage nanowire exhibits reversible photo-responsive properties due to the photo-switchable cis-trans isomerisation of the azo unit formed on the phage. This result shows that site-specific display of a peptide on bio-nanostructures through site-directed genetic mutagenesis can be translated into site-directed chemical reaction for developing advanced materials. The photo-responsive properties of the azo-M13-phage nanowires may open the door for the development of light controllable smart devices for use in non-linear optics, holography data storage, molecular antenna, and actuators. PMID:23673356

  1. Virus-based Photo-Responsive Nanowires Formed By Linking Site-Directed Mutagenesis and Chemical Reaction

    PubMed Central

    Murugesan, Murali; Abbineni, Gopal; Nimmo, Susan L.; Cao, Binrui; Mao, Chuanbin

    2013-01-01

    Owing to the genetic flexibility and error-free bulk production, bio-nanostructures such as filamentous phage showed great potential in materials synthesis, however, their photo-responsive behaviour is neither explored nor unveiled. Here we show M13 phage genetically engineered with tyrosine residues precisely fused to the major coat protein is converted into a photo-responsive organic nanowire by a site-specific chemical reaction with an aromatic amine to form an azo dye structure on the surface. The resulting azo-M13-phage nanowire exhibits reversible photo-responsive properties due to the photo-switchable cis-trans isomerisation of the azo unit formed on the phage. This result shows that site-specific display of a peptide on bio-nanostructures through site-directed genetic mutagenesis can be translated into site-directed chemical reaction for developing advanced materials. The photo-responsive properties of the azo-M13-phage nanowires may open the door for the development of light controllable smart devices for use in non-linear optics, holography data storage, molecular antenna, and actuators. PMID:23673356

  2. Novel form of X-linked nonsyndromic hearing loss with cochlear malformation caused by a mutation in the type IV collagen gene COL4A6.

    PubMed

    Rost, Simone; Bach, Elisa; Neuner, Cordula; Nanda, Indrajit; Dysek, Sandra; Bittner, Reginald E; Keller, Alexander; Bartsch, Oliver; Mlynski, Robert; Haaf, Thomas; Müller, Clemens R; Kunstmann, Erdmute

    2014-02-01

    Hereditary hearing loss is the most common human sensorineural disorder. Genetic causes are highly heterogeneous, with mutations detected in >40 genes associated with nonsyndromic hearing loss, to date. Whereas autosomal recessive and autosomal dominant inheritance is prevalent, X-linked forms of nonsyndromic hearing impairment are extremely rare. Here, we present a Hungarian three-generation family with X-linked nonsyndromic congenital hearing loss and the underlying genetic defect. Next-generation sequencing and subsequent segregation analysis detected a missense mutation (c.1771G>A, p.Gly591Ser) in the type IV collagen gene COL4A6 in all affected family members. Bioinformatic analysis and expression studies support this substitution as being causative. COL4A6 encodes the alpha-6 chain of type IV collagen of basal membranes, which forms a heterotrimer with two alpha-5 chains encoded by COL4A5. Whereas mutations in COL4A5 and contiguous X-chromosomal deletions involving COL4A5 and COL4A6 are associated with X-linked Alport syndrome, a nephropathy associated with deafness and cataract, mutations in COL4A6 alone have not been related to any hereditary disease so far. Moreover, our index patient and other affected family members show normal renal and ocular function, which is not consistent with Alport syndrome, but with a nonsyndromic type of hearing loss. In situ hybridization and immunostaining demonstrated expression of the COL4A6 homologs in the otic vesicle of the zebrafish and in the murine inner ear, supporting its role in normal ear development and function. In conclusion, our results suggest COL4A6 as being the fourth gene associated with X-linked nonsyndromic hearing loss. PMID:23714752

  3. Novel form of X-linked nonsyndromic hearing loss with cochlear malformation caused by a mutation in the type IV collagen gene COL4A6.

    PubMed

    Rost, Simone; Bach, Elisa; Neuner, Cordula; Nanda, Indrajit; Dysek, Sandra; Bittner, Reginald E; Keller, Alexander; Bartsch, Oliver; Mlynski, Robert; Haaf, Thomas; Müller, Clemens R; Kunstmann, Erdmute

    2014-02-01

    Hereditary hearing loss is the most common human sensorineural disorder. Genetic causes are highly heterogeneous, with mutations detected in >40 genes associated with nonsyndromic hearing loss, to date. Whereas autosomal recessive and autosomal dominant inheritance is prevalent, X-linked forms of nonsyndromic hearing impairment are extremely rare. Here, we present a Hungarian three-generation family with X-linked nonsyndromic congenital hearing loss and the underlying genetic defect. Next-generation sequencing and subsequent segregation analysis detected a missense mutation (c.1771G>A, p.Gly591Ser) in the type IV collagen gene COL4A6 in all affected family members. Bioinformatic analysis and expression studies support this substitution as being causative. COL4A6 encodes the alpha-6 chain of type IV collagen of basal membranes, which forms a heterotrimer with two alpha-5 chains encoded by COL4A5. Whereas mutations in COL4A5 and contiguous X-chromosomal deletions involving COL4A5 and COL4A6 are associated with X-linked Alport syndrome, a nephropathy associated with deafness and cataract, mutations in COL4A6 alone have not been related to any hereditary disease so far. Moreover, our index patient and other affected family members show normal renal and ocular function, which is not consistent with Alport syndrome, but with a nonsyndromic type of hearing loss. In situ hybridization and immunostaining demonstrated expression of the COL4A6 homologs in the otic vesicle of the zebrafish and in the murine inner ear, supporting its role in normal ear development and function. In conclusion, our results suggest COL4A6 as being the fourth gene associated with X-linked nonsyndromic hearing loss.

  4. Novel form of X-linked nonsyndromic hearing loss with cochlear malformation caused by a mutation in the type IV collagen gene COL4A6

    PubMed Central

    Rost, Simone; Bach, Elisa; Neuner, Cordula; Nanda, Indrajit; Dysek, Sandra; Bittner, Reginald E; Keller, Alexander; Bartsch, Oliver; Mlynski, Robert; Haaf, Thomas; Müller, Clemens R; Kunstmann, Erdmute

    2014-01-01

    Hereditary hearing loss is the most common human sensorineural disorder. Genetic causes are highly heterogeneous, with mutations detected in >40 genes associated with nonsyndromic hearing loss, to date. Whereas autosomal recessive and autosomal dominant inheritance is prevalent, X-linked forms of nonsyndromic hearing impairment are extremely rare. Here, we present a Hungarian three-generation family with X-linked nonsyndromic congenital hearing loss and the underlying genetic defect. Next-generation sequencing and subsequent segregation analysis detected a missense mutation (c.1771G>A, p.Gly591Ser) in the type IV collagen gene COL4A6 in all affected family members. Bioinformatic analysis and expression studies support this substitution as being causative. COL4A6 encodes the alpha-6 chain of type IV collagen of basal membranes, which forms a heterotrimer with two alpha-5 chains encoded by COL4A5. Whereas mutations in COL4A5 and contiguous X-chromosomal deletions involving COL4A5 and COL4A6 are associated with X-linked Alport syndrome, a nephropathy associated with deafness and cataract, mutations in COL4A6 alone have not been related to any hereditary disease so far. Moreover, our index patient and other affected family members show normal renal and ocular function, which is not consistent with Alport syndrome, but with a nonsyndromic type of hearing loss. In situ hybridization and immunostaining demonstrated expression of the COL4A6 homologs in the otic vesicle of the zebrafish and in the murine inner ear, supporting its role in normal ear development and function. In conclusion, our results suggest COL4A6 as being the fourth gene associated with X-linked nonsyndromic hearing loss. PMID:23714752

  5. The Effects of Scleral Collagen Cross-Linking Using Glyceraldehyde on the Progression of Form-Deprived Myopia in Guinea Pigs

    PubMed Central

    Chu, Yanhua; Cheng, Zhaohui; Liu, Jing; Wang, Ying; Guo, Haixia

    2016-01-01

    To investigate the effects of collagen cross-linking using glyceraldehyde on the biomechanical properties of the sclera and the axial elongation of form-deprived myopia in the guinea pig. Thirty-six guinea pigs were randomly assigned to four groups: FDM (form-deprived myopia); FDMG (form-deprived myopia treated with glyceraldehyde); FDMS (form-deprived myopia treated with 0.9% isotonic sodium chloride); and normal control (free of form-deprivation). FDM was achieved in the right eye using a latex facemask. The right eye in FDMG was treated with a posterior subtenon injection of 0.5 M glyceraldehyde; 0.9% isotonic sodium chloride was administered to the right eye in FDMS group using the same method. Axial length, refraction, and stress-strain of the sclera were measured at scheduled time points. The treated eyes were also examined histologically by light microscopy. It was found that glyceraldehyde treatment significantly increased the stiffness of the sclera in the FDM eyes and abnormalities have not been observed in the retina and optic nerve of the treated eyes. But the development of myopia was not affected. PMID:27504195

  6. The Effects of Scleral Collagen Cross-Linking Using Glyceraldehyde on the Progression of Form-Deprived Myopia in Guinea Pigs.

    PubMed

    Chu, Yanhua; Cheng, Zhaohui; Liu, Jing; Wang, Ying; Guo, Haixia; Han, Quanhong

    2016-01-01

    To investigate the effects of collagen cross-linking using glyceraldehyde on the biomechanical properties of the sclera and the axial elongation of form-deprived myopia in the guinea pig. Thirty-six guinea pigs were randomly assigned to four groups: FDM (form-deprived myopia); FDMG (form-deprived myopia treated with glyceraldehyde); FDMS (form-deprived myopia treated with 0.9% isotonic sodium chloride); and normal control (free of form-deprivation). FDM was achieved in the right eye using a latex facemask. The right eye in FDMG was treated with a posterior subtenon injection of 0.5 M glyceraldehyde; 0.9% isotonic sodium chloride was administered to the right eye in FDMS group using the same method. Axial length, refraction, and stress-strain of the sclera were measured at scheduled time points. The treated eyes were also examined histologically by light microscopy. It was found that glyceraldehyde treatment significantly increased the stiffness of the sclera in the FDM eyes and abnormalities have not been observed in the retina and optic nerve of the treated eyes. But the development of myopia was not affected. PMID:27504195

  7. The link in Linking

    PubMed Central

    Caldwell, Jane C; Chiale, Pablo A; Gonzalez, Mario D; Baranchuk, Adrian

    2013-01-01

    We present 2 cases of the slow-fast form of AVNRT with initially narrow QRS complexes followed by sudden unexpected transition to persistently wide QRS complexes due to aberrant intraventricular conduction. Introduction of a properly timed extrastimulus in one case and critical oscillations in cycle length due to short-long coupling in the second case set the stage for the initial bundle branch block. However, persistence of the aberrancy pattern once the initial event abated was maintained by the "linking" phenomenon. Delayed, retrograde concealed activation from the contralateral bundle branch perpetuated the initial bundle branch block. PMID:23840106

  8. Linking the X-ray and infrared properties of star-forming galaxies at z < 1.5

    NASA Astrophysics Data System (ADS)

    Symeonidis, M.; Georgakakis, A.; Page, M. J.; Bock, J.; Bonzini, M.; Buat, V.; Farrah, D.; Franceschini, A.; Ibar, E.; Lutz, D.; Magnelli, B.; Magdis, G.; Oliver, S. J.; Pannella, M.; Paolillo, M.; Rosario, D.; Roseboom, I. G.; Vaccari, M.; Villforth, C.

    2014-10-01

    We present the most complete study to date of the X-ray emission from star formation in high-redshift (median z = 0.7; z < 1.5), IR-luminous (LIR = 1010-1013 L⊙) galaxies detected by Herschel's PACS and SPIRE instruments. For our purpose, we take advantage of the deepest X-ray data to date, the Chandra Deep Fields (North and South). Sources which host AGN are removed from our analysis by means of multiple AGN indicators. We find an AGN fraction of 18 ± 2 per cent amongst our sample and note that AGN entirely dominate at values of log [LX/LIR] > -3 in both hard and soft X-ray bands. From the sources which are star formation dominated, only a small fraction are individually X-ray detected and for the bulk of the sample we calculate average X-ray luminosities through stacking. We find an average soft X-ray to infrared ratio of log = -4.3 and an average hard X-ray to infrared ratio of log = -3.8. We report that the X-ray/IR correlation is approximately linear through the entire range of LIR and z probed and, although broadly consistent with the local (z < 0.1) one, it does display some discrepancies. We suggest that these discrepancies are unlikely to be physical, i.e. due to an intrinsic change in the X-ray properties of star-forming galaxies with cosmic time, as there is no significant evidence for evolution of the LX/LIR ratio with redshift. Instead, they are possibly due to selection effects and remaining AGN contamination. We also examine whether dust obscuration in the galaxy plays a role in attenuating X-rays from star formation, by investigating changes in the LX/LIR ratio as a function of the average dust temperature. We conclude that X-rays do not suffer any measurable attenuation in the host galaxy.

  9. Star-forming dwarf galaxies in the Virgo cluster: the link between molecular gas, atomic gas, and dust

    NASA Astrophysics Data System (ADS)

    Grossi, M.; Corbelli, E.; Bizzocchi, L.; Giovanardi, C.; Bomans, D.; Coelho, B.; De Looze, I.; Gonçalves, T. S.; Hunt, L. K.; Leonardo, E.; Madden, S.; Menéndez-Delmestre, K.; Pappalardo, C.; Riguccini, L.

    2016-05-01

    We present 12CO(1-0) and 12CO(2-1) observations of a sample of 20 star-forming dwarfs selected from the Herschel Virgo Cluster Survey, with oxygen abundances ranging from 12 + log (O / H) ~ 8.1 to 8.8. CO emission is observed in ten galaxies and marginally detected in another one. CO fluxes correlate with the FIR 250 μm emission, and the dwarfs follow the same linear relation that holds for more massive spiral galaxies extended to a wider dynamical range. We compare different methods to estimate H2 molecular masses, namely a metallicity-dependent CO-to-H2 conversion factor and one dependent on H-band luminosity. The molecular-to-stellar mass ratio remains nearly constant at stellar masses ≲ 109 M⊙, contrary to the atomic hydrogen fraction, MHI/M∗, which increases inversely with M∗. The flattening of the MH2/M∗ ratio at low stellar masses does not seem to be related to the effects of the cluster environment because it occurs for both Hi-deficient and Hi-normal dwarfs. The molecular-to-atomic ratio is more tightly correlated with stellar surface density than metallicity, confirming that the interstellar gas pressure plays a key role in determining the balance between the two gaseous components of the interstellar medium. Virgo dwarfs follow the same linear trend between molecular gas mass and star formation rate as more massive spirals, but gas depletion timescales, τdep, are not constant and range between 100 Myr and 6 Gyr. The interaction with the Virgo cluster environment is removing the atomic gas and dust components of the dwarfs, but the molecular gas appears to be less affected at the current stage of evolution within the cluster. However, the correlation between Hi deficiency and the molecular gas depletion time suggests that the lack of gas replenishment from the outer regions of the disc is lowering the star formation activity. Based on observations carried out with the IRAM 30-m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany

  10. Competitive Intelligence.

    ERIC Educational Resources Information Center

    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…

  11. Academic Competitions.

    ERIC Educational Resources Information Center

    Marin County Office of Education, San Rafael, CA.

    Descriptions of scholastic competitions for Marin County (California) students are presented. Following a rationale for conducting scholastic competitions, community groups and businesses which lend support are listed along with the type of support given. Participating grade levels, dates of competition during the 1983-84 school year, and a brief…

  12. Non-ATP competitive protein kinase inhibitors.

    PubMed

    Garuti, L; Roberti, M; Bottegoni, G

    2010-01-01

    Protein kinases represent an attractive target in oncology drug discovery. Most of kinase inhibitors are ATP-competitive and are called type I inhibitors. The ATP-binding pocket is highly conserved among members of the kinase family and it is difficult to find selective agents. Moreover, the ATP-competitive inhibitors must compete with high intracellular ATP levels leading to a discrepancy between IC50s measured by biochemical versus cellular assays. The non-ATP competitive inhibitors, called type II and type III inhibitors, offer the possibility to overcome these problems. These inhibitors act by inducing a conformational shift in the target enzyme such that the kinase is no longer able to function. In the DFG-out form, the phenylalanine side chain moves to a new position. This movement creates a hydrophobic pocket available for occupation by the inhibitor. Some common features are present in these inhibitors. They contain a heterocyclic system that forms one or two hydrogen bonds with the kinase hinge residue. They also contain a hydrophobic moiety that occupies the pocket formed by the shift of phenylalanine from the DFG motif. Moreover, all the inhibitors bear a hydrogen bond donor-acceptor pair, usually urea or amide, that links the hinge-binding portion to the hydrophobic moiety and interacts with the allosteric site. Examples of non ATP-competitive inhibitors are available for various kinases. In this review small molecules capable of inducing the DFG-out conformation are reported, especially focusing on structural feature, SAR and biological properties.

  13. 48 CFR 1353.206 - Competition requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... FORMS FORMS Prescription of Forms 1353.206 Competition requirements. As prescribed in 48 CFR 1306.303-70, use Form CD-492, Justification for Other Than Full and Open Competition, to support the requirements... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Competition...

  14. 48 CFR 1353.206 - Competition requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... FORMS FORMS Prescription of Forms 1353.206 Competition requirements. As prescribed in 48 CFR 1306.303-70, use Form CD-492, Justification for Other Than Full and Open Competition, to support the requirements... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Competition...

  15. 48 CFR 1353.206 - Competition requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... FORMS FORMS Prescription of Forms 1353.206 Competition requirements. As prescribed in 48 CFR 1306.303-70, use Form CD-492, Justification for Other Than Full and Open Competition, to support the requirements... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Competition...

  16. 48 CFR 1353.206 - Competition requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... FORMS FORMS Prescription of Forms 1353.206 Competition requirements. As prescribed in 48 CFR 1306.303-70, use Form CD-492, Justification for Other Than Full and Open Competition, to support the requirements... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Competition...

  17. 48 CFR 1353.206 - Competition requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... FORMS FORMS Prescription of Forms 1353.206 Competition requirements. As prescribed in 48 CFR 1306.303-70, use Form CD-492, Justification for Other Than Full and Open Competition, to support the requirements... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Competition...

  18. Quality assurance/quality control of foot and mouth disease solid phase competition enzyme-linked immunosorbent assay--Part I. Quality assurance: development of secondary and working standards.

    PubMed

    Goris, N; De Clercq, K

    2005-12-01

    International movement in animals and animal products has urged organisations like the World Organisation for Animal Health (OIE) to draw up guidelines to regulate and facilitate trade between Member Countries. However, as the global market continues to grow, further standardisation and harmonisation of antibody detection assays for infectious diseases are needed, especially regarding the development and use of reference materials. For OIE notifiable diseases for which primary or international reference standards are available or under development, National or Regional Reference Laboratories are encouraged to establish their own secondary and/or working standards. This paper describes the development of standards for the foot and mouth disease (FMD) solid phase competition enzyme-linked immunosorbent assay using positive serum obtained from calves vaccinated against the FMD virus. The procedure outlined in this manuscript can easily be extrapolated to similar serological assays and should lead to further international harmonisation of assays and test results.

  19. Processing of N-linked oligosaccharides from precursor- to mature-form herpes simplex virus type 1 glycoprotein gC.

    PubMed Central

    Serafini-Cessi, F; Dall'Olio, F; Pereira, L; Campadelli-Fiume, G

    1984-01-01

    Immature and mature forms of glycoprotein gC were purified by immunoadsorbent from herpes simplex virus type 1-infected BHK cells labeled with [3H]mannose for a 20-min pulse or for 11 h followed by a 3-h chase. The nature of N-asparagine-linked oligosaccharides carried by the immature form, pgC (molecular weight = 92,000), and the mature gC (molecular weight = 120,000) has been investigated. All pronase-digested glycopeptides of pgC were susceptible to endo-beta-N-acetylglucosaminidase H treatment; thus they have a high-mannose structure. Using thin-layer chromatography to separate endo-beta-N-acetylglucosaminidase H-cleaved oligosaccharides, polymannosyl chains of different sizes, ranging from Man9GlcNAc to Man5GlcNAc, were separated. The major components were Man8GlcNAc and Man7GlcNAc, suggesting that pgC labeled in a 20-min pulse represents the form of glycoprotein already routed to the Golgi apparatus. Analysis of glycopeptides of mature gC showed that the majority (95%) of N-linked glycans were converted to complex-type glycans. Ion-exchange chromatography and affinity chromatography on concanavalin A-Sepharose and leucoagglutinin-agarose revealed that diantennary and triantennary glycans predominated, whereas tetrantennary chains were not present. Parts of the di- and triantennary chains were not fully sialylated. The high heterogeneity of complex-type chains found in mature gC may be related to the high number of N-glycosylation sites of the glycoprotein as predicted by DNA sequencing studies (Frink et al., J. Virol. 45:634-647, 1983). Images PMID:6088806

  20. Transglutaminse 2 and EGGL, the Protein Cross-Link Formed by Transglutaminse 2, As Therapeutic Targets for Disabilities of Old Age

    PubMed Central

    2013-01-01

    Abstract Aging of the extracellular matrix (ECM), the protein matrix that surrounds and penetrates the tissues and binds the body together, contributes significantly to functional aging of tissues. ECM proteins become increasingly cross-linked with age, and this cross-linking is probably important in the decline of the ECM's function. This article reviews the role of ε-(γ-glutamyl)-lysine (EGGL), a cross-link formed by transglutaminase enzymes, and particularly the widely expressed isozyme transglutaminase 2 (TG2), in the aging ECM. There is little direct data on EGGL accumulation with age, and no direct evidence of a role of EGGL in the aging of the ECM with pathology. However, several lines of circumstantial evidence suggest that EGGL accumulates with age, and its association with pathology suggests that this might reflect degradation of ECM function. TG activity increases with age in many circumstances. ECM protein turnover is such that some EGGL made by TG is likely to remain in place for years, if not decades, in healthy tissue, and both EGGL and TG levels are enhanced by age-related diseases. If further research shows EGGL does accumulate with age, removing it could be of therapeutic benefit. Also reviewed is the blockade of TG and active removal of EGGL as therapeutic strategies, with the conclusion that both have promise. EGGL removal may have benefit for acute fibrotic diseases, such as tendinopathy, and for treating generalized decline in ECM function with old age. Extracellular TG2 and EGGL are therefore therapeutic targets both for specific and more generalized diseases of aging. PMID:23968147

  1. Transglutaminse 2 and EGGL, the protein cross-link formed by transglutaminse 2, as therapeutic targets for disabilities of old age.

    PubMed

    Bains, William

    2013-12-01

    Aging of the extracellular matrix (ECM), the protein matrix that surrounds and penetrates the tissues and binds the body together, contributes significantly to functional aging of tissues. ECM proteins become increasingly cross-linked with age, and this cross-linking is probably important in the decline of the ECM's function. This article reviews the role of ε-(γ-glutamyl)-lysine (EGGL), a cross-link formed by transglutaminase enzymes, and particularly the widely expressed isozyme transglutaminase 2 (TG2), in the aging ECM. There is little direct data on EGGL accumulation with age, and no direct evidence of a role of EGGL in the aging of the ECM with pathology. However, several lines of circumstantial evidence suggest that EGGL accumulates with age, and its association with pathology suggests that this might reflect degradation of ECM function. TG activity increases with age in many circumstances. ECM protein turnover is such that some EGGL made by TG is likely to remain in place for years, if not decades, in healthy tissue, and both EGGL and TG levels are enhanced by age-related diseases. If further research shows EGGL does accumulate with age, removing it could be of therapeutic benefit. Also reviewed is the blockade of TG and active removal of EGGL as therapeutic strategies, with the conclusion that both have promise. EGGL removal may have benefit for acute fibrotic diseases, such as tendinopathy, and for treating generalized decline in ECM function with old age. Extracellular TG2 and EGGL are therefore therapeutic targets both for specific and more generalized diseases of aging. PMID:23968147

  2. The Genetically Modified Polysialylated Form of Neural Cell Adhesion Molecule-Positive Cells for Potential Treatment of X-Linked Adrenoleukodystrophy

    PubMed Central

    Jang, Jiho; Kim, Han-Soo; Kang, Joon Won

    2013-01-01

    Purpose Cell transplantation of myelin-producing exogenous cells is being extensively explored as a means of remyelinating axons in X-linked adrenoleukodystrophy. We determined whether 3,3',5-Triiodo-L-thyronine (T3) overexpresses the ABCD2 gene in the polysialylated (PSA) form of neural cell adhesion molecule (NCAM)-positive cells and promotes cell proliferation and favors oligodendrocyte lineage differentiation. Materials and Methods PSA-NCAM+ cells from newborn Sprague-Dawley rats were grown for five days on uncoated dishes in defined medium with or without supplementation of basic fibroblast growth factor (bFGF) and/or T3. Then, PSA-NCAM+ spheres were prepared in single cells and transferred to polyornithine/fibronectin-coated glass coverslips for five days to determine the fate of the cells according to the supplementation of these molecules. T3 responsiveness of ABCD2 was analyzed using real-time quantitative polymerase chain reaction, the growth and fate of cells were determined using 5-bromo-2-deoxyuridine incorporation and immunocytochemistry, respectively. Results Results demonstrated that T3 induces overexpression of the ABCD2 gene in PSA-NCAM+ cells, and can enhance PSA-NCAM+ cell growth in the presence of bFGF, favoring an oligodendrocyte fate. Conclusion These results may provide new insights into investigation of PSA-NCAM+ cells for therapeutic application to X-linked adrenoleukodystrophy. PMID:23225827

  3. Syndromic form of X-linked mental retardation with marked hypotonia in early life, severe mental handicap, and difficult adult behavior maps to Xp22.

    PubMed

    Turner, Gillian; Gedeon, Agi; Kerr, Bronwyn; Bennett, Rachael; Mulley, John; Partington, Michael

    2003-03-15

    An X-linked recessive syndromic form of mental retardation is described in a family in which 10 males in four generations were affected. The main manifestations were severe to profound intellectual disability, muscular hypotonia in childhood, delayed walking, and difficult, aggressive behavior. There was a moderate reduction both in occipitofrontal circumference (OFC) and height and a similar facial appearance, triangular in shape with a high forehead, prominent ears, and a small pointed chin. Linkage analysis located the gene at Xp22 with maximum lod scores of 4.8 at theta = 0.0 for markers mapping between the closest recombination points at DXS7104 and DXS418. The physical length of this region is approximately 6 Mb. Mutations in the GRPR gene and M6b genes were excluded by sequence analysis. Nearby genes in which mutations are known to be associated with mental retardation (RPS6KA3, STK9, and VCXA, B and C), were excluded by position.

  4. 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.

    PubMed

    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 (<1%), Sudan IV (<1%) and para 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%.

  5. Exploring the link between urban form and work related transportation using combined satellite image and census information: Case of the Great lakes region

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Guindon, Bert; Sun, Krista

    2016-05-01

    Aspects of urban transportation have significant implications for resource consumption and environmental quality. The level of travel activity, the viability of various modes of transportation and hence the level of transportation-related emissions are influenced by the structure of cities, i.e., their urban forms. While it is widely recognized that satellite remote sensing can provide spatial information on urban land cover and land use, its effective use for understanding impacts of urban form on issues such as transportation requires that this information be integrated with relevant demographic information. A comprehensive bi-national urban database, the Great Lakes Urban Survey (GLUS), comprising all cities with populations in excess of 200,000 has been created from Landsat imagery and national census and transportation survey information from Canada and the United States. A suite of analysis tools are proposed to utilize information sets such as GLUS to investigate the link between urban form and work-related travel. A new indicator, the Employment Deficit Measure (EDM), is proposed to quantify the balance between employment and worker availability at different transit horizons and hence to assess the viability of alternate modes of transportation. It is argued that the high degree of residential and commercial/industrial land uses greatly impact travel to work mode options as well as commute distance. A spatial interaction model is developed and found to accurately predict travel distance aggregated at the census tract level. We argue that this model could also be used to explore the relative levels of travel activity associated with different urban forms.

  6. Structure-based design of a disulfide-linked oligomeric form of the simian virus 40 (SV40) large T antigen DNA-binding domain

    SciTech Connect

    Meinke, Gretchen; Phelan, Paul; Fradet-Turcotte, Amélie; Archambault, Jacques; Bullock, Peter A.

    2011-06-01

    With the aim of forming the ‘lock-washer’ conformation of the origin-binding domain of SV40 large T antigen in solution, using structure-based analysis an intermolecular disulfide bridge was engineered into the origin-binding domain to generate higher order oligomers in solution. The 1.7 Å resolution structure shows that the mutant forms a spiral in the crystal and has the de novo disulfide bond at the protein interface, although structural rearrangements at the interface are observed relative to the wild type. The modular multifunctional protein large T antigen (T-ag) from simian virus 40 orchestrates many of the events needed for replication of the viral double-stranded DNA genome. This protein assembles into single and double hexamers on specific DNA sequences located at the origin of replication. This complicated process begins when the origin-binding domain of large T antigen (T-ag ODB) binds the GAGGC sequences in the central region (site II) of the viral origin of replication. While many of the functions of purified T-ag OBD can be studied in isolation, it is primarily monomeric in solution and cannot assemble into hexamers. To overcome this limitation, the possibility of engineering intermolecular disulfide bonds in the origin-binding domain which could oligomerize in solution was investigated. A recent crystal structure of the wild-type T-ag OBD showed that this domain forms a left-handed spiral in the crystal with six subunits per turn. Therefore, we analyzed the protein interface of this structure and identified two residues that could potentially support an intermolecular disulfide bond if changed to cysteines. SDS–PAGE analysis established that the mutant T-ag OBD formed higher oligomeric products in a redox-dependent manner. In addition, the 1.7 Å resolution crystal structure of the engineered disulfide-linked T-ag OBD is reported, which establishes that oligomerization took place in the expected manner.

  7. Justice and competitive markets.

    PubMed

    Brody, B A

    1987-02-01

    This essay challenges the view that the provision of health care must take place within a competitive-free system. The author argues that, presuming that there is a requirement to meet the demands of those who cannot pay for health care, a competitive market provides a good way to deal with injustices within the health care system. The author concludes that the demands for justice are best met when indigent individuals use some portion of the funds they receive from the government to purchase one of the many competing forms of health care. This scheme requires a competitive market in the delivery of health care.

  8. Cross-Linked Hydrogels Formed through Diels-Alder Coupling of Furan- and Maleimide-Modified Poly(methyl vinyl ether-alt-maleic acid).

    PubMed

    Stewart, S Alison; Backholm, Matilda; Burke, Nicholas A D; Stöver, Harald D H

    2016-02-23

    The Diels-Alder [4 + 2] cycloaddition between furan- and maleimide-functional polyanions was used to form cross-linked synthetic polymer hydrogels. Poly(methyl vinyl ether-alt-maleic anhydride) was reacted with furfurylamine or N-(2-aminoethyl)maleimide in acetonitrile to form pairs of furan- and maleimide-functionalized poly(methyl vinyl ether-alt-maleic acid)s. Mixtures of these mutually reactive polyanions in water gelled within 15 min to 18 h, depending on degree of functionalization and polymer concentrations. Solution and magic-angle spinning (1)H NMR were used to confirm the formation of the Diels-Alder adduct, to analyze competing hydrolytic side reactions, and demonstrate postgelation functionalization. The effect of the degree of furan and maleimide functionalization, polymer concentration, pH, and calcium ion concentration, on gelation time, gel mechanical properties, and equilibrium swelling, are described. Release of dextran as a model drug was studied using fluorescence spectroscopy, as a function of gel composition and calcium treatment. PMID:26800849

  9. Face-driven corner-linked octahedral nanocages: M6L8 cages formed by C3-symmetric triangular facial ligands linked via C4-symmetric square tetratopic Pd(II) ions at truncated octahedron corners.

    PubMed

    Moon, Dohyun; Kang, Sangmi; Park, Jaejoon; Lee, Kyungjae; John, Rohith P; Won, Hosik; Seong, Gi Hun; Kim, Yang Sun; Kim, Ghyung Hwa; Rhee, Hakjune; Lah, Myoung Soo

    2006-03-22

    The face-driven corner-linked truncated octahedral nanocages, [Pd6L8]12+ (1, L1 = N,N',N' '-tris(3-pyridinyl)-1,3,5-benzenetricarboxamide; 2, L2 = N,N',N' '-tris(4-pyridinylmethyl)-1,3,5-benzenetricarboxamide), were prepared with eight C3-symmetric tridentate ligands and six square planar tetratopic palladium(II) ions. The combination of the nitrogen donor atom at a approximately 120 degrees kink position of the carboxamido pyridinyl group and the tilted pyridyl versus the facial plane of the ligands can provide the needed curvature for the formation of octahedral cages. The nitrogen atoms can coordinate to the square planar palladium(II) ions to form kinks with approximately 120 degrees angles at the C4-symmetric square planar corners of the truncated octahedron. Depending on the conformation of the ligand, L1, two different truncated octahedral cages of around 2.4 nm in diameters were formed. The major form of 1 with syn-conformational ligands has a cavity volume of approximately 1600 A3. The cage has 12 ports (3.4 x 3.5 A2) at all edges of the octahedron. The minor form of cage 1 with anti-conformational ligands has a slightly increased cavity volume ( approximately 1900 A3) and port size (3.3 x 8.0 A2). The insertion of a methylene group in L2 has not only increased the cavity volume of 2 to approximately 2200 A3 but also enlarged the port size to 4.1 x 8.0 A2. However, an atomic force microscopy (AFM) study of cage 2 showed that the cages had a height of 1.8 +/- 0.1 nm. This value is about 30% smaller than the calculated size of 2.6 nm from the crystal structure. This tip-induced decrease in height in cage 2 suggests the nonrigidity of cage 2. PMID:16536521

  10. Oligo-[alpha]-deoxynucleotides covalently linked to an intercalating agent. Double helices with parallel strands are formed with complementary oligo-[beta]-deoxynucleotides.

    PubMed Central

    Sun, J S; Asseline, U; Rouzaud, D; Montenay-Garestier, T; Nguyen, T T; Hélène, C

    1987-01-01

    An oligo-[alpha]-deoxynucleotide of sequence (5')d(TCTAAACTC) (3') was synthesized using the alpha-anomers of deoxynucleosides and its 5'-phosphate was covalently linked to a 9-amino acridine derivative via a pentamethylene linker. Two oligo-[beta]-deoxynucleotides containing the complementary sequence in either the 5'----3' or the 3'----5' orientation were synthesized using natural [beta]-deoxynucleosides. Complex formation was investigated by absorption and fluorescence spectroscopies. No change in spectroscopic properties was detected with the anti-parallel [beta] sequence. Absorption changes were induced in the visible absorption band of the acridine derivative at 2 degrees C when the acridine-substituted oligo-[alpha]-deoxynucleotide was mixed in equimolecular amounts with the complementary [beta]-sequence in the parallel orientation. Hypochromism was observed in the UV range. The fluorescence of the acridine derivative was quenched by the guanine base present in the second position of the complementary sequence. Cooperative dissociation curves were observed and identical values of melting temperatures were obtained by absorption and fluorescence. An increase in salt concentration stabilized the complex with a delta Tm of 8 degrees C when NaCl concentration increased from 0.1 to 1 M. These results demonstrate that an oligo-[alpha]-deoxynucleotide covalently linked to an intercalating agent is able to form a double helix with an oligo-[beta]-deoxynucleotide. The two strands of this [alpha]-[beta] double helix adopt a parallel 5'----3' orientation. The acridine ring is able to intercalate between the first two base pairs on the 5'-side of the duplex structure. PMID:3627982

  11. IT product competition Network

    NASA Astrophysics Data System (ADS)

    Xu, Xiu-Lian; Zhou, Lei; Shi, Jian-Jun; Wang, Yong-Li; Feng, Ai-Xia; He, Da-Ren

    2008-03-01

    Along with the technical development, the IT product competition becomes increasingly fierce in recent years. The factories, which produce the same IT product, have to improve continuously their own product quality for taking a large piece of cake in the product sale market. We suggest using a complex network description for the IT product competition. In the network the factories are defined as nodes, and two nodes are connected by a link if they produce a common IT product. The edge represents the sale competition relationship. 2121 factories and 265 products have been investigated. Some statistical properties, such as the degree distribution, node strength distribution, assortativity, and node degree correlation have been empirically obtained.

  12. A comparative study of the interactions of cationic hetarenes with quadruplex-DNA forming oligonucleotide sequences of the insulin-linked polymorphic region (ILPR)

    PubMed Central

    Dzubiel, Darinka; Mahmoud, Mohamed M A; Thomas, Laura

    2014-01-01

    Summary The interactions of the ILPR sequence (ILPR = "insulin-linked polymorphic region") a2 [d(ACAG4TGTG4ACAG4TGTG4)] with [2.2.2]heptamethinecyanine derivatives 1a–e and with the already established quadruplex ligands coralyne (2), 3,3′-[2,6-pyridinediylbis(carbonylimino)]bis[1-methylquinolinium] (3), 4,4′,4′′,4′′′-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis[1-methylpyridinium] (4), naphtho[2,1-b:3,4-b′:6,5-b′′:7,8-b′′′]tetraquinolizinium (5) and thiazole orange (6) were studied. It is demonstrated with absorption, fluorescence and CD spectroscopy that all investigated ligands bind with relatively high affinity to the ILPR-quadruplex DNA a2 (0.2–5.5 × 106 M−1) and that in most cases the binding parameters of ligand-ILPR complexes are different from the ones observed with other native quadruplex-forming DNA sequences. PMID:25550763

  13. Validation according to OIE criteria of a monoclonal, recombinant p26-based, serologic competitive enzyme-linked immunosorbent assay as screening method in surveillance programs for the detection of Equine infectious anemia virus antibodies.

    PubMed

    Nardini, Roberto; Autorino, Gian Luca; Ricci, Ida; Frontoso, Raffaele; Rosone, Francesca; Simula, Massimiliano; Scicluna, Maria Teresa

    2016-03-01

    The Italian National Reference Center for equine infectious anemia (CRAIE; Rome, Italy) developed and validated a monoclonal, recombinant p26-based competitive enzyme-linked immunosorbent assay (cELISA) for the detection of EIA virus antibodies employing the 2010 criteria of the World Organization for Animal Health (OIE). The following parameters were evaluated: cutoff values, repeatability, reproducibility, concordance, analytical sensitivity (Se), absolute analytical specificity (Sp), and diagnostic Se and Sp. Positive and negative predictive values were also defined in relation to the estimated prevalence. When the cELISA was used as a screening test for 96,468 samples in the Italian EIA surveillance program, 17% more EIA cases were detected than by the agar gel immunodiffusion test, and the apparent diagnostic Sp estimated from these samples was 99.8%, which was more than the diagnostic Sp (80.2%) estimated from validation. The high Se and Sp of the cELISA confirm its fit for purpose as a screening test.

  14. Chemical structure and properties of interstrand cross-links formed by reaction of guanine residues with abasic sites in duplex DNA.

    PubMed

    Catalano, Michael J; Liu, Shuo; Andersen, Nisana; Yang, Zhiyu; Johnson, Kevin M; Price, Nathan E; Wang, Yinsheng; Gates, Kent S

    2015-03-25

    A new type of interstrand cross-link resulting from the reaction of a DNA abasic site with a guanine residue on the opposing strand of the double helix was recently identified, but the chemical connectivity of the cross-link was not rigorously established. The work described here was designed to characterize the chemical structure and properties of dG-AP cross-links generated in duplex DNA. The approach involved characterization of the nucleoside cross-link "remnant" released by enzymatic digestion of DNA duplexes containing the dG-AP cross-link. We first carried out a chemical synthesis and complete spectroscopic structure determination of the putative cross-link remnant 9b composed of a 2-deoxyribose adduct attached to the exocyclic N(2)-amino group of dG. A reduced analogue of the cross-link remnant was also prepared (11b). Liquid chromatography-tandem mass spectrometric (LC-MS/MS) analysis revealed that the retention times and mass spectral properties of synthetic standards 9b and 11b matched those of the authentic cross-link remnants released by enzymatic digestion of duplexes containing the native and reduced dG-AP cross-link, respectively. These results establish the chemical connectivity of the dG-AP cross-link released from duplex DNA and provide a foundation for detection of this lesion in biological samples. The dG-AP cross-link in duplex DNA was remarkably stable, decomposing with a half-life of 22 days at pH 7 and 23 °C. The intrinsic chemical stability of the dG-AP cross-link suggests that this lesion in duplex DNA may have the power to block DNA-processing enzymes involved in transcription and replication.

  15. EDITORIAL: Physics competitions Physics competitions

    NASA Astrophysics Data System (ADS)

    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

  16. The UV–Optical Color Gradients in Star-forming Galaxies at 0.5 < z < 1.5: Origins and Link to Galaxy Assembly

    NASA Astrophysics Data System (ADS)

    Liu, F. S.; Jiang, Dongfei; Guo, Yicheng; Koo, David C.; Faber, S. M.; Zheng, Xianzhong; Yesuf, Hassen M.; Barro, Guillermo; Li, Yao; Li, Dingpeng; Wang, Weichen; Mao, Shude; Fang, Jerome J.

    2016-05-01

    The rest-frame UV–optical (i.e., NUV ‑ B) color index is sensitive to the low-level recent star formation and dust extinction, but it is insensitive to the metallicity. In this Letter, we have measured the rest-frame NUV ‑ B color gradients in ˜1400 large (r e > 0.″18), nearly face-on (b/a > 0.5) main sequence star-forming galaxies (SFGs) between redshift 0.5 and 1.5 in the CANDELS/GOODS-S and UDS fields. With this sample, we study the origin of UV–optical color gradients in the SFGs at z ˜ 1 and discuss their link with the buildup of stellar mass. We find that the more massive, centrally compact, and more dust extinguished SFGs tend to have statistically more negative raw color gradients (redder centers) than the less massive, centrally diffuse, and less dusty SFGs. After correcting for dust reddening based on optical-spectral energy distribution fitting, the color gradients in the low-mass (M * < 1010 M ⊙) SFGs generally become quite flat, while most of the high-mass (M * > 1010.5 M ⊙) SFGs still retain shallow negative color gradients. These findings imply that dust reddening is likely the principal cause of negative color gradients in the low-mass SFGs, while both increased central dust reddening and buildup of compact old bulges are likely the origins of negative color gradients in the high-mass SFGs. These findings also imply that at these redshifts the low-mass SFGs buildup their stellar masses in a self-similar way, while the high-mass SFGs grow inside out.

  17. Competitive spirit

    NASA Astrophysics Data System (ADS)

    2000-01-01

    Leicester University will host the 65 international teams of students who will assemble in July for this year's International Physics Olympiad . The last time the Olympiad came to the UK was in 1986 in London, and it was the notable enthusiasm of the Leicester Physics and Astronomy department which persuaded the Olympiad Committee to give them the chance of organizing the prestigious event. The students taking part from all over the world are studying physics at A-level or an equivalent standard and they will take part in an intellectual marathon of theoretical and practical examinations. Each national team comprises five students selected from three rounds of competition and the teams will receive an official welcome from the city, as well as opportunities to visit some of the important educational and cultural centres of the surrounding region. The finalists will also be able to test their skills and initiative at the Challenger Learning Centre, which forms part of Leicester's new National Space Science Centre. Specific information on the event can be found on the Olympiad-2000 website at www.star.le.ac.uk/IphO-2000 . The Rudolf Ortvay problem solving contest in physics, which takes place in November, is a tradition of Eötvös University in Budapest, Hungary. The competition was first opened to international participants in 1998, enabling students from universities around the world to show their knowledge, ingenuity, problem-solving skills and physical insight into problems that are far beyond routine level. The problems (30 - 35 each year) are chosen from different branches of theoretical as well as applied physics. They have varying levels of difficulty, and every contestant can send solutions for ten problems. The focus is not on school-level problem-solving routines but rather on the `physical' way of thinking, recognition of the heart of the problem and an appropriate choice of mathematics. The majority of the assigned problems are original, few having

  18. Competitive spirit

    NASA Astrophysics Data System (ADS)

    2000-01-01

    Leicester University will host the 65 international teams of students who will assemble in July for this year's International Physics Olympiad . The last time the Olympiad came to the UK was in 1986 in London, and it was the notable enthusiasm of the Leicester Physics and Astronomy department which persuaded the Olympiad Committee to give them the chance of organizing the prestigious event. The students taking part from all over the world are studying physics at A-level or an equivalent standard and they will take part in an intellectual marathon of theoretical and practical examinations. Each national team comprises five students selected from three rounds of competition and the teams will receive an official welcome from the city, as well as opportunities to visit some of the important educational and cultural centres of the surrounding region. The finalists will also be able to test their skills and initiative at the Challenger Learning Centre, which forms part of Leicester's new National Space Science Centre. Specific information on the event can be found on the Olympiad-2000 website at www.star.le.ac.uk/IphO-2000 . The Rudolf Ortvay problem solving contest in physics, which takes place in November, is a tradition of Eötvös University in Budapest, Hungary. The competition was first opened to international participants in 1998, enabling students from universities around the world to show their knowledge, ingenuity, problem-solving skills and physical insight into problems that are far beyond routine level. The problems (30 - 35 each year) are chosen from different branches of theoretical as well as applied physics. They have varying levels of difficulty, and every contestant can send solutions for ten problems. The focus is not on school-level problem-solving routines but rather on the `physical' way of thinking, recognition of the heart of the problem and an appropriate choice of mathematics. The majority of the assigned problems are original, few having

  19. Development and validation of a competitive enzyme-linked immunosorbent assay for the measurement of total plasma immunoglobulins in healthy loggerhead sea (Caretta caretta) and green turtles (Chelonia mydas).

    PubMed

    Kaplan, Amy J; Stacy, Nicole I; Jacobson, Elliott; Le-Bert, Carolina R; Nollens, Hendrik H; Origgi, Francesco C; Green, Linda G; Bootorabi, Shadi; Bolten, Alan; Hernandez, Jorge A

    2016-01-01

    The quantification of circulating plasma immunoglobulins represents a valuable diagnostic tool in human and veterinary immunology, although its application is very limited in reptile medicine to date. The objectives of our study were the development and standardization of a competitive enzyme-linked immunosorbent assay (cELISA) for the measurement of total plasma immunoglobulins (Igs; both IgM and IgY) in loggerhead sea turtles (LST; Caretta caretta; n = 254) and green turtles (GT; Chelonia mydas; n = 111), the establishment of reference intervals for Ig for both species, and the examination of associations between Ig and total protein (TP), condition index, and water temperature. The cELISA for Ig was successfully developed and optimized. Reference intervals for Ig were 0.38-0.94 g/dL in LST (median: 0.59 g/dL; range: 0.16-2.15 g/dL) and 0.40-0.85 g/dL in GT (median: 0.58 g/dL; range: 0.18-1.80 g/dL). In LST, there were positive linear relationships of Ig with TP, and TP with Ig and condition index, and a negative relationship of Ig with condition index. The positive linear relationships of Ig with TP, and TP with Ig were also identified in GT. These positive associations of Ig and TP were expected, as Ig represents fractions of TP, and TP reportedly increases with straight carapace length and weight. The negative association of Ig with condition index may indicate potential biological variations. The cELISA and reference intervals for total Ig of LST and GT presented herein have the potential to be useful as a diagnostic and research tool for sea turtle immunology.

  20. Development and validation of a competitive enzyme-linked immunosorbent assay for the measurement of total plasma immunoglobulins in healthy loggerhead sea (Caretta caretta) and green turtles (Chelonia mydas).

    PubMed

    Kaplan, Amy J; Stacy, Nicole I; Jacobson, Elliott; Le-Bert, Carolina R; Nollens, Hendrik H; Origgi, Francesco C; Green, Linda G; Bootorabi, Shadi; Bolten, Alan; Hernandez, Jorge A

    2016-01-01

    The quantification of circulating plasma immunoglobulins represents a valuable diagnostic tool in human and veterinary immunology, although its application is very limited in reptile medicine to date. The objectives of our study were the development and standardization of a competitive enzyme-linked immunosorbent assay (cELISA) for the measurement of total plasma immunoglobulins (Igs; both IgM and IgY) in loggerhead sea turtles (LST; Caretta caretta; n = 254) and green turtles (GT; Chelonia mydas; n = 111), the establishment of reference intervals for Ig for both species, and the examination of associations between Ig and total protein (TP), condition index, and water temperature. The cELISA for Ig was successfully developed and optimized. Reference intervals for Ig were 0.38-0.94 g/dL in LST (median: 0.59 g/dL; range: 0.16-2.15 g/dL) and 0.40-0.85 g/dL in GT (median: 0.58 g/dL; range: 0.18-1.80 g/dL). In LST, there were positive linear relationships of Ig with TP, and TP with Ig and condition index, and a negative relationship of Ig with condition index. The positive linear relationships of Ig with TP, and TP with Ig were also identified in GT. These positive associations of Ig and TP were expected, as Ig represents fractions of TP, and TP reportedly increases with straight carapace length and weight. The negative association of Ig with condition index may indicate potential biological variations. The cELISA and reference intervals for total Ig of LST and GT presented herein have the potential to be useful as a diagnostic and research tool for sea turtle immunology. PMID:26699523

  1. Competitive sports for the disabled.

    PubMed

    Clark, M W

    1980-01-01

    A full life experience for people with and without physical disabilities usually includes some form of recreation or sport. Competition adds to enjoyment of sport for many people and can improve morale. This paper reviews some of the competitive opportunities available for people with a physical disability. These include competition within existing "able-bodied" organizations with or without adaptive devices and competition in separate organizations for those with disabilities. The latter include the National Wheelchair Basketball Association and the National Wheelchair Athletic Association.

  2. EDITORIAL: Physics competitions Physics competitions

    NASA Astrophysics Data System (ADS)

    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

  3. Competitive intransitivity, population interaction structure, and strategy coexistence.

    PubMed

    Laird, Robert A; Schamp, Brandon S

    2015-01-21

    Intransitive competition occurs when competing strategies cannot be listed in a hierarchy, but rather form loops-as in the game rock-paper-scissors. Due to its cyclic competitive replacement, competitive intransitivity promotes strategy coexistence, both in rock-paper-scissors and in higher-richness communities. Previous work has shown that this intransitivity-mediated coexistence is strongly influenced by spatially explicit interactions, compared to when populations are well mixed. Here, we extend and broaden this line of research and examine the impact on coexistence of intransitive competition taking place on a continuum of small-world networks linking spatial lattices and regular random graphs. We use simulations to show that the positive effect of competitive intransitivity on strategy coexistence holds when competition occurs on networks toward the spatial end of the continuum. However, in networks that are sufficiently disordered, increasingly violent fluctuations in strategy frequencies can lead to extinctions and the prevalence of monocultures. We further show that the degree of disorder that leads to the transition between these two regimes is positively dependent on population size; indeed for very large populations, intransitivity-mediated strategy coexistence may even be possible in regular graphs with completely random connections. Our results emphasize the importance of interaction structure in determining strategy dynamics and diversity.

  4. Bifunctional Binding of Cisplatin to DNA: Why Does Cisplatin Form 1,2-Intrastrand Cross-links with AG, But Not with GA?

    PubMed Central

    Mantri, Yogita; Lippard, Stephen J.; Baik, Mu-Hyun

    2008-01-01

    The bifunctional binding of the anticancer drug cisplatin to two adjacent nucleobases in DNA is modeled using density functional theory. Previous experimental studies revealed that cisplatin binding to adjacent guanine and adenine is sensitive to nucleobase sequence. Whereas AG 1,2-intrastrand cross-links are commonly observed, the analogous GA adducts are not known. This study focuses on understanding this directional preference by constructing a full reaction profile using quantum chemical simulation methods. Monofunctional and bifunctional cisplatin adducts were generated and the transition states that connect them were located for the dinucleotides d(pApG) and d(pGpA), assuming that initial platination takes place at the guanine site. Our computer simulations reveal a significant kinetic preference for formation of the AG over the GA adduct. The activation free energies of ~23 kcal/mol for AG and ~32 kcal/mol for GA suggest that bifunctional closure is ~6 orders of magnitude faster for AG than for GA. Responsible for the stabilization of the transition state that affords the AG adduct is a strong hydrogen bond between one of the ammine ligands of cisplatin and the 5′ phosphate group of the DNA backbone. This interaction is absent in the transition state that leads to the GA adduct, because the right-handed helix of the DNA backbone places the phosphate out of reach for the ammine ligand. We found only an insignificant thermodynamic difference between AG and GA adducts and conclude that the preference of AG over GA binding is largely under kinetic control. The puckering of the deoxyribose ring plays an important role in determining the energetics of the bifunctional platination products. Whereas the 3′-nucleoside remains in the native C2′-endo/C3′-exo form of B-DNA, the deoxyribose of the 5′-nucleoside always adopts the C2′-exo/C3′-endo puckering in our simulations. A detailed analysis of the energies and structures of the bifunctional adducts

  5. EDITORIAL: Physics competitions Physics competitions

    NASA Astrophysics Data System (ADS)

    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

  6. Inhibition of Coxsackie B Virus Infection by Soluble Forms of Its Receptors: Binding Affinities, Altered Particle Formation, and Competition with Cellular Receptors

    PubMed Central

    Goodfellow, Ian G.; Evans, David J.; Blom, Anna M.; Kerrigan, Dave; Miners, J. Scott; Morgan, B. Paul; Spiller, O. Brad

    2005-01-01

    We previously reported that soluble decay-accelerating factor (DAF) and coxsackievirus-adenovirus receptor (CAR) blocked coxsackievirus B3 (CVB3) myocarditis in mice, but only soluble CAR blocked CVB3-mediated pancreatitis. Here, we report that the in vitro mechanisms of viral inhibition by these soluble receptors also differ. Soluble DAF inhibited virus infection through the formation of reversible complexes with CVB3, while binding of soluble CAR to CVB induced the formation of altered (A) particles with a resultant irreversible loss of infectivity. A-particle formation was characterized by loss of VP4 from the virions and required incubation of CVB3-CAR complexes at 37°C. Dimeric soluble DAF (DAF-Fc) was found to be 125-fold-more effective at inhibiting CVB3 than monomeric DAF, which corresponded to a 100-fold increase in binding affinity as determined by surface plasmon resonance analysis. Soluble CAR and soluble dimeric CAR (CAR-Fc) bound to CVB3 with 5,000- and 10,000-fold-higher affinities than the equivalent forms of DAF. While DAF-Fc was 125-fold-more effective at inhibiting virus than monomeric DAF, complement regulation by DAF-Fc was decreased 4 fold. Therefore, while the virus binding was a cooperative event, complement regulation was hindered by the molecular orientation of DAF-Fc, indicating that the regions responsible for complement regulation and virus binding do not completely overlap. Relative contributions of CVB binding affinity, receptor binding footprint on the virus capsid, and induction of capsid conformation alterations for the ability of cellular DAF and CAR to act as receptors are discussed. PMID:16140777

  7. Malaysian competition

    SciTech Connect

    Jeffs, E.

    1994-11-01

    Two years ago, the first tentative steps were taken to privatize the Malaysian electricity supply industry with the flotation of 25 percent of Tenaga Nasional Bhd. At the same time the terms were defined for independent power generation, and plans were drawn up for six projects. Now, with six independent power producer projects under construction adding more capacity than the partly privatized TNB, the utility`s station managers are concerned they will be at a competitive disadvantage unless they can operate under the same type of power sales agreement.

  8. Interstrand cross-links are preferentially formed at the d(GC) sites in the reaction between cis-diamminedichloroplatinum (II) and DNA.

    PubMed

    Lemaire, M A; Schwartz, A; Rahmouni, A R; Leng, M

    1991-03-01

    A DNA restriction fragment with convergent SP6 and T7 promoters has undergone reaction with cis-diamminedichloroplatinum(II) (cis-DDP) and was then used as a template for RNA synthesis in vitro. The T7 and SP6 RNA polymerases generate fragments of defined sizes. Analysis of the RNA fragments shows that the polymerases are mainly blocked at the level of the d(GG) and d(AG) sites and to a lesser extent at the level of the d(GC) sites. The adducts at the d(GC) sites are more resistant to cyanide ion attack than those at the major sites and are identified as interstrand cross-links. The formation of an interstrand cross-link between the N-7 atoms of two guanine residues at the d(GC) sites was further confirmed by chemical modifications. PMID:2000402

  9. Post-Colonialism Perspectives on Educational Competition

    ERIC Educational Resources Information Center

    Yeh, Chuan-Rong

    2016-01-01

    Educational competition has always been the puzzle issue of educational researches. In this article, I analyze several aspects of educational competition within the perspective of post-colonialism discourse. In the political aspect, Taiwanese education is linked with political power, to present the post-colonial spirit by continuing dynastic…

  10. Estimation of the Number of Cross-Links of Multi-walled Carbon Nanotube Films Formed by a Dehydration Condensation Reaction

    NASA Astrophysics Data System (ADS)

    Ogino, S.; Sato, Y.; Yamamoto, G.; Sasamori, K.; Kimura, H.; Hashida, T.; Motomiiya, K.; Jeyadevan, B.; Tohji, K.

    2007-03-01

    Preparation procedure of multi-walled carbon nanotube (MWCNT) films shows as follows. First, as-grown MWCNTs heated in the air and treated with hydrochloric acid to remove amorphous carbon and catalytic metal particles respectively. Then, the o1btained MWCNT samples were treated with nitric acid at 373K to add carboxylic acid and hydroxyl groups on their surface. Finally, MWCNT films were prepared by employing a condensation reaction utilizing 1,3-dicyclohexylcarbodiimide (DCC) to cross-link each MWCNT with chemical bonds. Morphological changes in the resultant MWCNT films were monitored using scanning electron microscopy, and showed that the MWCNTs were randomly intertwined in the films. The prepared MWCNT films were 17mm in diameter and 20μm in thickness, and the apparent density was 0.59 g/cm3. Fourier transform-infrared spectroscopy confirmed that each MWCNT modified with carboxylic acid and hydroxyl groups was cross-linked through the ester bond. It was found that the ratio of the number of ester cross-links and carbon atoms of the nanotubes per unit apparent volume (cm3) of condensed-MWCNT films was 5.23×10-3 using TGA. The tensile strength and Vickers hardness of condensed-MWCNT films achieved an average of 15MPa and 9.2MPa, respectively, and was greater than those of free-standing MWCNT films without ester bond.

  11. Electrophysiological evidence for emotional valence and competitive arousal effects on insight problem solving.

    PubMed

    Li, Yadan; Xiao, Xiao; Ma, Wenjuan; Jiang, Jun; Qiu, Jiang; Zhang, Qinglin

    2013-11-13

    Accumulating evidence suggests that insight can be substantially influenced by task-irrelevant emotion stimuli and interpersonal competitive situation, and a close link might exist between them. Using a learning-testing paradigm and Event-Related Potentials (ERPs), the present study investigated the independent and joint effects of emotional and competitive information on insight problem solving especially their neural mechanisms. Subjects situated in either competitive or non-competitive condition learned heuristic logogriphs first and then viewed task-irrelevant positive or negative emotional pictures, which were followed by test logogriphs to solve. Both behavioral and ERP findings showed a more evident insight boost following negative emotional pictures in competitive context. Results demonstrated that negative emotion and competitive situation might promote insight by a defocused mode of attention (as indicated by N1 and P2), the enhanced semantic integration and breaking mental set (as indicated by N450), and the increased forming of novel associations activated by motivational arousal originating from competition (as indicated by P800-1600 and P1600-2500). These results indicate that the dynamic interactions between emotional valence and competitive arousal effects on insight.

  12. Crystal structure of a nucleoside model for the inter-strand cross-link formed by the reaction of 2'-de-oxy-guanosine and an abasic site in duplex DNA.

    PubMed

    Catalano, Michael J; Ruddraraju, Kasi Viswanatharaju; Barnes, Charles L; Gates, Kent S

    2016-05-01

    The title compound, 9-[(2R,4S,5R)-4-hy-droxy-5-(hy-droxy-meth-yl)tetra-hydro-furan-2-yl]-2-{[(2R,4S,5R)-4-meth-oxy-5-(meth-oxy-meth-yl)tetra-hydro-furan-2-yl]amino}-1H-purin-6(9H)-one, C17H25N5O7, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. In the crystal, the guanosine moieties of mol-ecules A and B are linked by N-H⋯N and O-H⋯N hydrogen-bonding inter-actions, forming ribbons which are stacked to form columns along [100]. These columns are then linked by O-H⋯O hydrogen bonds between the ribose moieties and numerous C-H⋯O inter-actions to complete the three-dimensional structure. PMID:27308004

  13. Autonomy Support and Its Links to Physical Activity and Competitive Performance: Mediations through Motivation, Competence, Action Orientation and Harmonious Passion, and the Moderator Role of Autonomy Support by Perceived Competence

    ERIC Educational Resources Information Center

    Halvari, Hallgeir; Ulstad, Svein Olav; Bagoien, Tor Egil; Skjesol, Knut

    2009-01-01

    The purpose of the present study was to test a Self-Determination Theory (SDT) process model in relation to involvement in physical activity and competitive performance among students (N = 190). In this model, perceived autonomy support from teachers and coaches was expected to be positively related to autonomous motivation, perceived competence,…

  14. Competitive Science: Is Competition Ruining Science?

    PubMed Central

    Casadevall, Arturo

    2015-01-01

    Science has always been a competitive undertaking. Despite recognition of the benefits of cooperation and team science, reduced availability of funding and jobs has made science more competitive than ever. Here we consider the benefits of competition in providing incentives to scientists and the adverse effects of competition on resource sharing, research integrity, and creativity. The history of science shows that transformative discoveries often occur in the absence of competition, which only emerges once fields are established and goals are defined. Measures to encourage collaboration and ameliorate competition in the scientific enterprise are discussed. PMID:25605760

  15. Competitive science: is competition ruining science?

    PubMed

    Fang, Ferric C; Casadevall, Arturo

    2015-04-01

    Science has always been a competitive undertaking. Despite recognition of the benefits of cooperation and team science, reduced availability of funding and jobs has made science more competitive than ever. Here we consider the benefits of competition in providing incentives to scientists and the adverse effects of competition on resource sharing, research integrity, and creativity. The history of science shows that transformative discoveries often occur in the absence of competition, which only emerges once fields are established and goals are defined. Measures to encourage collaboration and ameliorate competition in the scientific enterprise are discussed.

  16. Competitive science: is competition ruining science?

    PubMed

    Fang, Ferric C; Casadevall, Arturo

    2015-04-01

    Science has always been a competitive undertaking. Despite recognition of the benefits of cooperation and team science, reduced availability of funding and jobs has made science more competitive than ever. Here we consider the benefits of competition in providing incentives to scientists and the adverse effects of competition on resource sharing, research integrity, and creativity. The history of science shows that transformative discoveries often occur in the absence of competition, which only emerges once fields are established and goals are defined. Measures to encourage collaboration and ameliorate competition in the scientific enterprise are discussed. PMID:25605760

  17. Lunabotics Mining Competition

    NASA Technical Reports Server (NTRS)

    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.

  18. DYNLT (Tctex-1) forms a tripartite complex with dynein intermediate chain and RagA, hence linking this small GTPase to the dynein motor.

    PubMed

    Merino-Gracia, Javier; García-Mayoral, María Flor; Rapali, Peter; Valero, Ruth Ana; Bruix, Marta; Rodríguez-Crespo, Ignacio

    2015-10-01

    It has been suggested that DYNLT, a dynein light chain known to bind to various cellular and viral proteins, can function as a microtubule-cargo adaptor. Recent data showed that DYNLT links the small GTPase Rab3D to microtubules and, for this to occur, the DYNLT homodimer needs to display a binding site for dynein intermediate chain together with a binding site for the small GTPase. We have analysed in detail how RagA, another small GTPase, associates to DYNLT. After narrowing down the binding site of RagA to DYNLT we could identify that a β strand, part of the RagA G3 box involved in nucleotide binding, mediates this association. Interestingly, we show that both microtubule-associated DYNLT and cytoplasmic DYNLT are equally able to bind to the small GTPases Rab3D and RagA. Using NMR spectroscopy, we analysed the binding of dynein intermediate chain and RagA to mammalian DYNLT. Our experiments identify residues of DYNLT affected by dynein intermediate chain binding and residues affected by RagA binding, hence distinguishing the docking site for each of them. In summary, our results shed light on the mechanisms adopted by DYNLT when binding to protein cargoes that become transported alongside microtubules bound to the dynein motor.

  19. Antisense Proline-Arginine RAN dipeptides linked to C9ORF72-ALS/FTD form toxic nuclear aggregates that initiate in vitro and in vivo neuronal death

    PubMed Central

    Wen, Xinmei; Tan, Wenzhi; Westergard, Thomas; Krishnamurthy, Karthik; ShamamandriMarkandaiah, Shashirekha; Shi, Yingxiao; Lin, Shaoyu; Shneider, Neil A.; Monaghan, John; Pandey, Udai B.; Pasinelli, Piera; Ichida, Justin K.; Trotti, Davide

    2015-01-01

    SUMMARY Expanded GGGGCC nucleotide repeats within the C9ORF72 gene are the most common genetic mutation associated with both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Sense and antisense transcripts of these expansions are translated to form five dipeptide repeat proteins (DRPs). We employed primary cortical and motor neuron cultures, live-cell imaging, and transgenic fly models and found that the arginine-rich dipeptides, in particular Proline-Arginine (PR), are potently neurotoxic. Factors that anticipated their neurotoxicity included aggregation in nucleoli, decreased number of processing bodies, and stress granules formation, implying global translational dysregulation as path accountable for toxicity. Nuclear PR aggregates were also found in human-induced motor neurons and postmortem spinal cord tissues from C9ORF72 ALS and ALS/FTD patients. Intronic G4C2 transcripts, but not loss of C9ORF72 protein, are also toxic to motor and cortical neurons. Interestingly, G4C2 transcript-mediated neurotoxicity synergizes with that of PR aggregates, suggesting convergence of mechanisms. PMID:25521377

  20. A Disulfide Bond-forming Machine Is Linked to the Sortase-mediated Pilus Assembly Pathway in the Gram-positive Bacterium Actinomyces oris.

    PubMed

    Reardon-Robinson, Melissa E; Osipiuk, Jerzy; Chang, Chungyu; Wu, Chenggang; Jooya, Neda; Joachimiak, Andrzej; Das, Asis; Ton-That, Hung

    2015-08-28

    Export of cell surface pilins in Gram-positive bacteria likely occurs by the translocation of unfolded precursor polypeptides; however, how the unfolded pilins gain their native conformation is presently unknown. Here, we present physiological studies to demonstrate that the FimA pilin of Actinomyces oris contains two disulfide bonds. Alanine substitution of cysteine residues forming the C-terminal disulfide bridge abrogates pilus assembly, in turn eliminating biofilm formation and polymicrobial interaction. Transposon mutagenesis of A. oris yielded a mutant defective in adherence to Streptococcus oralis, and revealed the essential role of a vitamin K epoxide reductase (VKOR) gene in pilus assembly. Targeted deletion of vkor results in the same defects, which are rescued by ectopic expression of VKOR, but not a mutant containing an alanine substitution in its conserved CXXC motif. Depletion of mdbA, which encodes a membrane-bound thiol-disulfide oxidoreductase, abrogates pilus assembly and alters cell morphology. Remarkably, overexpression of MdbA or a counterpart from Corynebacterium diphtheriae, rescues the Δvkor mutant. By alkylation assays, we demonstrate that VKOR is required for MdbA reoxidation. Furthermore, crystallographic studies reveal that A. oris MdbA harbors a thioredoxin-like fold with the conserved CXXC active site. Consistently, each MdbA enzyme catalyzes proper disulfide bond formation within FimA in vitro that requires the catalytic CXXC motif. Because the majority of signal peptide-containing proteins encoded by A. oris possess multiple Cys residues, we propose that MdbA and VKOR constitute a major folding machine for the secretome of this organism. This oxidative protein folding pathway may be a common feature in Actinobacteria.

  1. Crystal structure of a nucleoside model for the inter­strand cross-link formed by the reaction of 2′-de­oxy­guanosine and an abasic site in duplex DNA

    PubMed Central

    Catalano, Michael J.; Ruddraraju, Kasi Viswanatharaju; Barnes, Charles L.; Gates, Kent S.

    2016-01-01

    The title compound, 9-[(2R,4S,5R)-4-hy­droxy-5-(hy­droxy­meth­yl)tetra­hydro­furan-2-yl]-2-{[(2R,4S,5R)-4-meth­oxy-5-(meth­oxy­meth­yl)tetra­hydro­furan-2-yl]amino}-1H-purin-6(9H)-one, C17H25N5O7, crystallizes with two independent mol­ecules (A and B) in the asymmetric unit. In the crystal, the guanosine moieties of mol­ecules A and B are linked by N—H⋯N and O—H⋯N hydrogen-bonding inter­actions, forming ribbons which are stacked to form columns along [100]. These columns are then linked by O—H⋯O hydrogen bonds between the ribose moieties and numerous C—H⋯O inter­actions to complete the three-dimensional structure. PMID:27308004

  2. Below ground competition among invading detritivores

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The factors regulating soil animal communities are poorly understood. Current theory favors niche complementarity and facilitation over competition as the primary forms of non-trophic interspecific interaction in soil fauna. However, competition frequently has been suggested as an important communi...

  3. Competitive Bidding in Medicare: Who Benefits From Competition?

    PubMed Central

    Song, Zirui; Landrum, Mary Beth; Chernew, Michael E.

    2012-01-01

    Objectives To conduct the first empirical study of competitive bidding in Medicare. Study Design and Methods We analyzed 2006–2010 Medicare Advantage data from the Centers for Medicare & Medicaid Services using longitudinal models adjusted for market and plan characteristics. Results A $1 increase in Medicare's payment to health maintenance organization (HMO) plans led to a $0.49 (P <.001) increase in plan bids, with $0.34 (P <.001) going to beneficiaries in the form of extra benefits or lower cost sharing. With preferred provider organization and private fee-for-service plans included, higher Medicare payments increased bids less ($0.33 per dollar), suggesting more competition among these latter plans. Conclusions As a market-based alternative to cost control through administrative pricing, competitive bidding relies on private insurance plans proposing prices they are willing to accept for insuring a beneficiary. However, competition is imperfect in the Medicare bidding market. As much as half of every dollar in increased plan payment went to higher bids rather than to beneficiaries. While having more insurers in a market lowered bids, the design of any bidding system for Medicare should recognize this shortcoming of competition. PMID:23009305

  4. Cooperation Improves Success during Intergroup Competition: An Analysis Using Data from Professional Soccer Tournaments.

    PubMed

    David, Gwendolyn Kim; Wilson, Robbie Stuart

    2015-01-01

    The benefit mutually gained by cooperators is considered the ultimate explanation for why cooperation evolved among non-relatives. During intergroup competition, cooperative behaviours within groups that provide a competitive edge over their opposition should be favoured by selection, particularly in lethal human warfare. Aside from forming larger groups, three other ways that individuals within a group can cooperate to improve their chances of gaining a mutual benefit are: (i) greater networking, (ii) contributing more effort, and (iii) dividing labour. Greater cooperation is expected to increase the chances of gaining a group benefit by improving proficiency in the tasks critical to success-yet empirical tests of this prediction using real-world cases are absent. In this study, we used data derived from 12 international and professional soccer competitions to test the predictions that: 1) greater levels of cooperative behaviour are associated with winning group contests, 2) the three forms of cooperation differ in relative importance for winning matches, 3) competition and tournament-type affect the levels of cooperation and shooting proficiency in matches, and 4) greater levels of networking behaviour are associated with increased proficiency in the most critical task linked with winning success in soccer-shooting at goal. Winners were best predicted by higher shooting proficiency, followed by greater frequencies of networking interactions within a team but unexpectedly, fewer networking partners and less division of labour. Although significant variation was detected across competitions and tournament-types, greater levels of networking behaviour were consistently associated with increased proficiency in shooting at goal, which in turn was linked with winning success. This study empirically supports the idea that intergroup competition can favour cooperation among non-relatives. PMID:26313929

  5. Interference competition and species coexistence.

    PubMed Central

    Amarasekare, Priyanga

    2002-01-01

    Interference competition is ubiquitous in nature. Yet its effects on resource exploitation remain largely unexplored for species that compete for dynamic resources. Here, I present a model of exploitative and interference competition with explicit resource dynamics. The model incorporates both biotic and abiotic resources. It considers interference competition both in the classical sense (i.e. each species suffers a net reduction in per capita growth rate via interference from, and interference on, the other species) and in the broad sense (i.e. each species suffers a net reduction in per capita growth rate via interference from, but can experience an increase in growth rate via interference on, the other species). Coexistence cannot occur under classical interference competition even when the species inferior at resource exploitation is superior at interference. Such a trade-off can, however, change the mechanism of competitive exclusion from dominance by the superior resource exploiter to a priority effect. Now the inferior resource exploiter can exclude the superior resource exploiter provided it has a higher initial abundance. By contrast, when interference is beneficial to the interacting species, coexistence is possible via a trade-off between exploitation and interference. These results hold regardless of whether the resource is biotic or abiotic, indicating that the outcome of exploitative and interference competition does not depend on the exact nature of resource dynamics. The model makes two key predictions. First, species that engage in costly interference mechanisms (e.g. territoriality, overgrowth or undercutting, allelopathy and other forms of chemical competition) should not be able to coexist unless they also engage in beneficial interference mechanisms (e.g. predation or parasitism). Second, exotic invasive species that displace native biota should be superior resource exploiters that have strong interference effects on native species with little

  6. Strategic planning and competition

    SciTech Connect

    Gang, W.G. )

    1994-02-01

    This article discusses how to formulate a successful strategic plan in the face of competition from other electric utilities. Areas covered include reasons for plan failure, competitive simulations to test strategic plans, intelligence gathering, and cost reduction through reorganization.

  7. Lunar Regolith Excavation Competition

    NASA Technical Reports Server (NTRS)

    Liles, Cassandra

    2009-01-01

    The Lunar Regolith Excavation Competition is a new competition that needs graphics, logos, rules, as well as an arena. Although this is the first year of the competition, the competition is modeled after an existing competition, the Centennial Lunar Excavator Challenge. This competition however is aimed at college students. This makes the challenge identifying key aspects of the original competition and modeling them to fit into an easier task, and creating exciting advertisement that helps encourage participation. By using a youth focus group, young insight, as well as guiding advice from experts in the field, hopefully an arena can be designed and built, rules can be molded and created to fit, and alluring graphics can be printed to bring about a successful first year of the Lunar Regolith Excavation Competition.

  8. Competition in Courtship.

    ERIC Educational Resources Information Center

    Laner, Mary Riege

    1986-01-01

    Explores both positive and negative competition within premarital relationships using a typology of competitive behaviors. Findings compare competitive activities of men and women in serious mate-choice oriented relationships. Implications for both courtship and marital relationships are offered. (Author/BL)

  9. In Defence of Competition.

    ERIC Educational Resources Information Center

    Prvulovich, Zika Rad

    1982-01-01

    Examines objections to competition as presented by educational philosopher Michael Fielding and others. The two major types of criticism of competition are that it is unfair and divisive and that it is selfish and immoral. The author advocates educational experiences which combine self-competition with cooperation. (AM)

  10. Gaining the Competitive Edge.

    ERIC Educational Resources Information Center

    American Society for Training and Development, Alexandria, VA.

    Economic competitiveness is today's most critical issue. Keeping the United States competitive in the world marketplace means the difference between a rising standard of living for everyone and the disappearance of what is taken for granted as a way of life. Developing human capital is the route toward successful competition, as some examples…

  11. Competitive Anxiety in Sport.

    ERIC Educational Resources Information Center

    Martens, Rainer; And Others

    This book is a comprehensive review of competitive anxiety research that has used the Sport Competition Anxiety Test, or SCAT (a trait scale), and the Competitive State Anxiety Inventory-2 (CSAI-2). The book describes the theoretical basis and development procedures for both scales, including detailed information on reliability and validity. In…

  12. Strategizing for Intense Competition.

    ERIC Educational Resources Information Center

    Hahn, William; Bourgeois, Ernest J., Jr.

    1999-01-01

    Examines trend toward more aggressive student recruiting strategies by colleges and universities, applying a model that assesses five competitive forces-cause and effect of competition, the expanding marketplace, substitute products, buyer power, and supplier power, and examines various strategies for dealing with these competitive forces, such as…

  13. Community Links

    ERIC Educational Resources Information Center

    Nelson, Mary

    1975-01-01

    At Moraine Valley Community College (Illinois), a chain of events, programs, activities, and services has linked the college and community in such areas as fine arts, ethnic groups, public services, community action, community service, and community education. (Author/NHM)

  14. Sexual and social competition: broadening perspectives by defining female roles.

    PubMed

    Rubenstein, Dustin R

    2012-08-19

    Males figured more prominently than females in Darwin's view of sexual selection. He considered female choice of secondary importance to male-male competition as a mechanism to explain the evolution of male ornaments and armaments. Fisher later demonstrated the importance of female choice in driving male trait evolution, but his ideas were largely ignored for decades. As sexual selection came to embrace the notions of parent-offspring and sexual conflict, and experimental tests of female choice showed promise, females began to feature more prominently in the framework of sexual selection theory. Recent debate over this theory has centred around the role of females, not only over the question of choice, but also over female-female competition. Whereas some have called for expanding the sexual selection framework to encompass all forms of female-female competition, others have called for subsuming sexual selection within a broader framework of social selection, or replacing it altogether. Still others have argued for linking sexual selection more clearly to other evolutionary theories such as kin selection. Rather than simply debating terminology, we must take a broader view of the general processes that lead to trait evolution in both sexes by clearly defining the roles that females play in the process, and by focusing on intra- and inter-sexual interactions in males and females.

  15. Link Analysis

    NASA Astrophysics Data System (ADS)

    Donoho, Steve

    Link analysis is a collection of techniques that operate on data that can be represented as nodes and links. This chapter surveys a variety of techniques including subgraph matching, finding cliques and K-plexes, maximizing spread of influence, visualization, finding hubs and authorities, and combining with traditional techniques (classification, clustering, etc). It also surveys applications including social network analysis, viral marketing, Internet search, fraud detection, and crime prevention.

  16. Matching Effective HR Practices with Competitive Strategy.

    ERIC Educational Resources Information Center

    Schuler, Randall S.; And Others

    1987-01-01

    Examines links between three competitive strategies (cost reduction, quality improvement, and innovation) and human resources (HR) practices. Describes a framework for ensuring that the two are made compatible and illustrates the process by showing how one $20 million business wrestled with these compatibility issues. (CH)

  17. Belowground competition among invading detritivores.

    PubMed

    Chang, Chih-Han; Szlavecz, Katalin; Filley, Timothy; Buyer, Jeffrey S; Bernard, Michael J; Pitz, Scott L

    2016-01-01

    The factors regulating soil animal communities are poorly understood. Current theory favors niche complementarity and facilitation over competition as the primary forms of non-trophic interspecific interaction in soil fauna; however, competition has frequently been suggested as an important community-structuring factor in earthworms, ecosystem engineers that influence belowground processes. To date, direct evidence of competition in earthworms is lacking due to the difficulty inherent in identifying a limiting resource for saprophagous animals. In the present study, we offer the first direct evidence of interspecific competition for food in this dominant soil detritivore group by combining field observations with laboratory mesocosm experiments using 13C and 15N double-enriched leaf litter to track consumption patterns. In our experiments, the Asian invasive species Amynthas hilgendorfi was a dominant competitor for leaf litter against two European species currently invading the temperate deciduous forests in North America. This competitive advantage may account for recent invasion success of A. hilgendorfi in forests with established populations of European species, and we hypothesize that specific phenological differences play an important role in determining the outcome of the belowground competition. In contrast, Eisenoides lonnbergi, a common native species in the Eastern United States, occupied a unique trophic position with limited interactions with other species, which may contribute to its persistence in habitats dominated by invasive species. Furthermore, our results supported neither the hypothesis that facilitation occurs between species of different functional groups nor the hypothesis that species in the same group exhibit functional equivalency in C and N translocation in the soil. We propose that species identity is a more powerful approach to understand earthworm invasion and its impacts on belowground processes.

  18. Belowground competition among invading detritivores.

    PubMed

    Chang, Chih-Han; Szlavecz, Katalin; Filley, Timothy; Buyer, Jeffrey S; Bernard, Michael J; Pitz, Scott L

    2016-01-01

    The factors regulating soil animal communities are poorly understood. Current theory favors niche complementarity and facilitation over competition as the primary forms of non-trophic interspecific interaction in soil fauna; however, competition has frequently been suggested as an important community-structuring factor in earthworms, ecosystem engineers that influence belowground processes. To date, direct evidence of competition in earthworms is lacking due to the difficulty inherent in identifying a limiting resource for saprophagous animals. In the present study, we offer the first direct evidence of interspecific competition for food in this dominant soil detritivore group by combining field observations with laboratory mesocosm experiments using 13C and 15N double-enriched leaf litter to track consumption patterns. In our experiments, the Asian invasive species Amynthas hilgendorfi was a dominant competitor for leaf litter against two European species currently invading the temperate deciduous forests in North America. This competitive advantage may account for recent invasion success of A. hilgendorfi in forests with established populations of European species, and we hypothesize that specific phenological differences play an important role in determining the outcome of the belowground competition. In contrast, Eisenoides lonnbergi, a common native species in the Eastern United States, occupied a unique trophic position with limited interactions with other species, which may contribute to its persistence in habitats dominated by invasive species. Furthermore, our results supported neither the hypothesis that facilitation occurs between species of different functional groups nor the hypothesis that species in the same group exhibit functional equivalency in C and N translocation in the soil. We propose that species identity is a more powerful approach to understand earthworm invasion and its impacts on belowground processes. PMID:27008785

  19. Clusters and the new economics of competition.

    PubMed

    Porter, M E

    1998-01-01

    Economic geography in an era of global competition poses a paradox. In theory, location should no longer be a source of competitive advantage. Open global markets, rapid transportation, and high-speed communications should allow any company to source any thing from any place at any time. But in practice, Michael Porter demonstrates, location remains central to competition. Today's economic map of the world is characterized by what Porter calls clusters: critical masses in one place of linked industries and institutions--from suppliers to universities to government agencies--that enjoy unusual competitive success in a particular field. The most famous example are found in Silicon Valley and Hollywood, but clusters dot the world's landscape. Porter explains how clusters affect competition in three broad ways: first, by increasing the productivity of companies based in the area; second, by driving the direction and pace of innovation; and third, by stimulating the formation of new businesses within the cluster. Geographic, cultural, and institutional proximity provides companies with special access, closer relationships, better information, powerful incentives, and other advantages that are difficult to tap from a distance. The more complex, knowledge-based, and dynamic the world economy becomes, the more this is true. Competitive advantage lies increasingly in local things--knowledge, relationships, and motivation--that distant rivals cannot replicate. Porter challenges the conventional wisdom about how companies should be configured, how institutions such as universities can contribute to competitive success, and how governments can promote economic development and prosperity. PMID:10187248

  20. Approximate kernel competitive learning.

    PubMed

    Wu, Jian-Sheng; Zheng, Wei-Shi; Lai, Jian-Huang

    2015-03-01

    Kernel competitive learning has been successfully used to achieve robust clustering. However, kernel competitive learning (KCL) is not scalable for large scale data processing, because (1) it has to calculate and store the full kernel matrix that is too large to be calculated and kept in the memory and (2) it cannot be computed in parallel. In this paper we develop a framework of approximate kernel competitive learning for processing large scale dataset. The proposed framework consists of two parts. First, it derives an approximate kernel competitive learning (AKCL), which learns kernel competitive learning in a subspace via sampling. We provide solid theoretical analysis on why the proposed approximation modelling would work for kernel competitive learning, and furthermore, we show that the computational complexity of AKCL is largely reduced. Second, we propose a pseudo-parallelled approximate kernel competitive learning (PAKCL) based on a set-based kernel competitive learning strategy, which overcomes the obstacle of using parallel programming in kernel competitive learning and significantly accelerates the approximate kernel competitive learning for large scale clustering. The empirical evaluation on publicly available datasets shows that the proposed AKCL and PAKCL can perform comparably as KCL, with a large reduction on computational cost. Also, the proposed methods achieve more effective clustering performance in terms of clustering precision against related approximate clustering approaches.

  1. Approximate kernel competitive learning.

    PubMed

    Wu, Jian-Sheng; Zheng, Wei-Shi; Lai, Jian-Huang

    2015-03-01

    Kernel competitive learning has been successfully used to achieve robust clustering. However, kernel competitive learning (KCL) is not scalable for large scale data processing, because (1) it has to calculate and store the full kernel matrix that is too large to be calculated and kept in the memory and (2) it cannot be computed in parallel. In this paper we develop a framework of approximate kernel competitive learning for processing large scale dataset. The proposed framework consists of two parts. First, it derives an approximate kernel competitive learning (AKCL), which learns kernel competitive learning in a subspace via sampling. We provide solid theoretical analysis on why the proposed approximation modelling would work for kernel competitive learning, and furthermore, we show that the computational complexity of AKCL is largely reduced. Second, we propose a pseudo-parallelled approximate kernel competitive learning (PAKCL) based on a set-based kernel competitive learning strategy, which overcomes the obstacle of using parallel programming in kernel competitive learning and significantly accelerates the approximate kernel competitive learning for large scale clustering. The empirical evaluation on publicly available datasets shows that the proposed AKCL and PAKCL can perform comparably as KCL, with a large reduction on computational cost. Also, the proposed methods achieve more effective clustering performance in terms of clustering precision against related approximate clustering approaches. PMID:25528318

  2. The components of kin competition.

    PubMed

    Van Dyken, J David

    2010-10-01

    It is well known that competition among kin alters the rate and often the direction of evolution in subdivided populations. Yet much remains unclear about the ecological and demographic causes of kin competition, or what role life cycle plays in promoting or ameliorating its effects. Using the multilevel Price equation, I derive a general equation for evolution in structured populations under an arbitrary intensity of kin competition. This equation partitions the effects of selection and demography, and recovers numerous previous models as special cases. I quantify the degree of kin competition, α, which explicitly depends on life cycle. I show how life cycle and demographic assumptions can be incorporated into kin selection models via α, revealing life cycles that are more or less permissive of altruism. As an example, I give closed-form results for Hamilton's rule in a three-stage life cycle. Although results are sensitive to life cycle in general, I identify three demographic conditions that give life cycle invariant results. Under the infinite island model, α is a function of the scale of density regulation and dispersal rate, effectively disentangling these two phenomena. Population viscosity per se does not impede kin selection.

  3. The genes encoding gonadal and nongonadal forms of 3[beta]-hydroxysteroid dehydrogenase/[Delta][sup 5]-[Delta][sup 4] isomerase are closely linked on mouse chromosome 3

    SciTech Connect

    Bain, P.A.; Meisler, M.H.; Payne, A.H. ); Taylor, B.A. )

    1993-04-01

    The biosynthesis of steroid hormones in the gonads and adrenal glands requires the activities of the enzyme 3[beta]-hydroxysteriod dehydrogenanse/isomerase (3[beta]HSD) which catalyzes the NAD[sup +]-dependant dehydrogenation and subsequent [Delta][sup 5] [r arrow] [Delta][sup 4] isomerization of[Delta][sup 5]-3[beta]-hydroxysteriods to [Delta][sup 4]-3-ketosteroids. The mouse expresses four isoforms of 3[beta]HSD. 3[beta]HSD I is expressed in gonads and adrenal glands and appears to be the major steroidogenic form, 3[beta]HSDs II and III are expressed in both liver and kidneys, and 3[beta]HSD IV has been detected only in kidneys. To determine the genetic relationship between the 3[beta]HSD isoforms, the authors have mapped the chromosomal locations of the four genes by linkage analysis using gene-specific process derived from the 3[prime] untranslated regions of 3 [beta]HSD cDNA clones. The four 3[beta]HSD structural genes (Hsd3b) are closely linked within a segment of chromosome 3 that is conserved on human chromosome 1. The order of markers on Chr 3 surrounding Hsd3b is: centromere-Gba-(4.4 [+-] 2.2)-Hsd3b-(3.3 [+-] 1.9)-Tshb-(6.7 [+-] 2.7)-Amy-1. 28 refs., 5 figs.

  4. Linking Literacy and Movement

    ERIC Educational Resources Information Center

    Pica, Rae

    2010-01-01

    There are many links between literacy and movement. Movement and language are both forms of communication and self-expression. Rhythm is an essential component of both language and movement. While people may think of rhythm primarily in musical terms, there is a rhythm to words and sentences as well. Individuals develop an internal rhythm when…

  5. Four paths of competition

    SciTech Connect

    Studness, C.M.

    1995-05-01

    The financial community`s focus on utility competition has been riveted on the proceedings now in progress at state regulatory commissions. The fear that something immediately damaging will come out of these proceedings seems to have diminished in recent months, and the stock market has reacted favorably. However, regulatory developments are only one of four paths leading to competition; the others are the marketplace, the legislatures, and the courts. Each could play a critical role in the emergence of competition.

  6. Achievement motivation and competition: perceptions and responses.

    PubMed

    Scanlan, T K; Ragan, J T

    1978-01-01

    This study investigated the influence of achievement motivation (Nach) on how individuals perceive an evaluative competition situation, whether they prefer to perform in this type of setting, and whether they seek the inherent appraisal information regarding their motoric competence. Specifically, perceived threat to self esteem was examined as indicated by state anxiety responses and measured by the Competitive Short Form of the Spielberger State Anxiety Inventory. State anxiety was assessed at rest, while performing a motor task alone in a nonevaluative setting, and during competition against an equal ability opponent. Situation perference and information seeking behavior were assessed at the conclusion of the closely paced competition. Subjects were asked whether they had perferred performing in the noncompetition or competition situation and were given the opportunity to select the relative ability level of a future opponent. As predicted, the major findings indicated that high Nach males experienced less threat during competition than low Nach males. Further, more high than low Nach individuals perferred the competition situation to the noncompetition situation and sought the evaluative ability information to a greater extent by choosing opponents of equal or greater relative ability for a future hypothetical competition.

  7. Cell competition in vertebrate organ size regulation.

    PubMed

    Penzo-Méndez, Alfredo I; Stanger, Ben Z

    2014-01-01

    The study of animal organ size determination has provided evidence of the existence of organ-intrinsic mechanisms that 'sense' and adjust organ growth. Cell competition, a form of cell interaction that equalizes cell population growth, has been proposed to play a role in organ size regulation. Cell competition involves a cell-context dependent response triggered by perceived differences in cell growth and/or proliferation rates, resulting in apoptosis in growth-disadvantaged cells and compensatory expansion of the more 'fit' cells. The mechanisms that allow cells to compare growth are not yet understood, but a number of genes and pathways have been implicated in cell competition. These include Myc, the members of the Hippo, JAK/STAT and WNT signaling pathways, and the Dlg/Lgl/Scrib and the Crb/Std/PatJ membrane protein complexes. Cell competition was initially characterized in the Drosophila imaginal disc, but several recent studies have shown that cell competition occurs in mouse embryonic stem cells and in the embryonic epiblast, where it plays a role in the regulation of early embryo size. In addition, competition-like behavior has been described in the adult mouse liver and the hematopoietic stem cell compartment. These data indicate that cell competition plays a more universal role in organ size regulation. In addition, as some authors have suggested that similar types of competitive behavior may operate in during tumorigenesis, there may be additional practical reasons for understanding this fundamental process of intercellular communication.

  8. Female competition and aggression: interdisciplinary perspectives

    PubMed Central

    Stockley, Paula; Campbell, Anne

    2013-01-01

    This paper introduces a Theme Issue combining interdisciplinary perspectives in the study of female competition and aggression. Despite a history of being largely overlooked, evidence is now accumulating for the widespread evolutionary significance of female competition. Here, we provide a synthesis of contributions to this Theme Issue on humans and other vertebrates, and highlight directions for future research. Females compete for resources needed to survive and reproduce, and for preferred mates. Although female aggression takes diverse forms, under most circumstances relatively low-risk competitive strategies are favoured, most probably due to constraints of offspring production and care. In social species, dominance relationships and threats of punishment can resolve social conflict without resort to direct aggression, and coalitions or alliances may reduce risk of retaliation. Consistent with these trends, indirect aggression is a low cost but effective form of competition among young women. Costs are also minimized by flexibility in expression of competitive traits, with aggressive behaviour and competitive signalling tailored to social and ecological conditions. Future research on female competition and the proximate mediators of female aggression will be greatly enhanced by opportunities for interdisciplinary exchange, as evidenced by contributions to this Theme Issue. PMID:24167303

  9. Reproductive efficiency and shade avoidance plasticity under simulated competition.

    PubMed

    Fazlioglu, Fatih; Al-Namazi, Ali; Bonser, Stephen P

    2016-07-01

    Plant strategy and life-history theories make different predictions about reproductive efficiency under competition. While strategy theory suggests under intense competition iteroparous perennial plants delay reproduction and semelparous annuals reproduce quickly, life-history theory predicts both annual and perennial plants increase resource allocation to reproduction under intense competition. We tested (1) how simulated competition influences reproductive efficiency and competitive ability (CA) of different plant life histories and growth forms; (2) whether life history or growth form is associated with CA; (3) whether shade avoidance plasticity is connected to reproductive efficiency under simulated competition. We examined plastic responses of 11 herbaceous species representing different life histories and growth forms to simulated competition (spectral shade). We found that both annual and perennial plants invested more to reproduction under simulated competition in accordance with life-history theory predictions. There was no significant difference between competitive abilities of different life histories, but across growth forms, erect species expressed greater CA (in terms of leaf number) than other growth forms. We also found that shade avoidance plasticity can increase the reproductive efficiency by capitalizing on the early life resource acquisition and conversion of these resources into reproduction. Therefore, we suggest that a reassessment of the interpretation of shade avoidance plasticity is necessary by revealing its role in reproduction, not only in competition of plants.

  10. Reproductive efficiency and shade avoidance plasticity under simulated competition.

    PubMed

    Fazlioglu, Fatih; Al-Namazi, Ali; Bonser, Stephen P

    2016-07-01

    Plant strategy and life-history theories make different predictions about reproductive efficiency under competition. While strategy theory suggests under intense competition iteroparous perennial plants delay reproduction and semelparous annuals reproduce quickly, life-history theory predicts both annual and perennial plants increase resource allocation to reproduction under intense competition. We tested (1) how simulated competition influences reproductive efficiency and competitive ability (CA) of different plant life histories and growth forms; (2) whether life history or growth form is associated with CA; (3) whether shade avoidance plasticity is connected to reproductive efficiency under simulated competition. We examined plastic responses of 11 herbaceous species representing different life histories and growth forms to simulated competition (spectral shade). We found that both annual and perennial plants invested more to reproduction under simulated competition in accordance with life-history theory predictions. There was no significant difference between competitive abilities of different life histories, but across growth forms, erect species expressed greater CA (in terms of leaf number) than other growth forms. We also found that shade avoidance plasticity can increase the reproductive efficiency by capitalizing on the early life resource acquisition and conversion of these resources into reproduction. Therefore, we suggest that a reassessment of the interpretation of shade avoidance plasticity is necessary by revealing its role in reproduction, not only in competition of plants. PMID:27547325

  11. Linking sperm length and velocity: the importance of intramale variation.

    PubMed

    Fitzpatrick, John L; Garcia-Gonzalez, Francisco; Evans, Jonathan P

    2010-12-23

    Selection imposed through sperm competition is commonly thought to promote the evolution of longer sperm, since sperm length is assumed to be positively associated with sperm swimming velocity. Yet, the basis for this assumption remains controversial, and there is surprisingly little intraspecific evidence demonstrating such a link between sperm form and function. Here, we show that sperm length and velocity are highly correlated in the sea urchin Heliocidaris erythrogramma, but importantly we report that failure to account for within-male variation in these sperm traits can obscure this relationship. These findings, in conjunction with the mounting evidence for extremely high levels of intra-specific variance in sperm traits, suggest that a functional link between sperm morphology and velocity may be more prevalent than what current evidence suggests. Our findings also suggest that selection for faster swimming sperm may promote the evolution of longer sperm, thereby supporting recent findings from macroevolutionary studies. PMID:20484233

  12. Displacement enzyme linked aptamer assay.

    PubMed

    Baldrich, Eva; Acero, Josep Lluis; Reekmans, Gunter; Laureyn, Wim; O'Sullivan, Ciara K

    2005-08-01

    Immense effort has been placed on the realization of immunoassays exploiting displacement of a suboptimum target, due to the ease of use and applicability to immunochromatographic strips and immunosensors. Most of the efforts reported to date focus on the use of a suboptimal target that is displaceable by the target toward which the antibody has higher affinity. Limited success has been achieved due to difficulty in obtaining suboptimal targets to which the antibody has enough affinity to bind while at the same time having lower levels of affinity in comparison to the target to facilitate displacement. Aptamers are synthetic oligonucleotides specifically selected to bind a certain target. Thanks to their high affinity and sensitivity, aptamers appear as alternative candidates to antibodies for analytical devices and several enzyme-linked aptamer assays and aptasensors have been reported. Aptamers, in contrast to antibodies, require the formation of a three-dimensional structure for target binding and can thus be anticipated to have a much higher affinity for binding its target rather than a modified form of the target (e.g., enzyme-labeled target). This phenomenon can be exploited for the development of a displacement assay, using enzyme-labeled target as a suboptimal displaceable molecule. Here, we report the first demonstration of the exploitation of an aptamer in an extremely rapid and highly sensitive displacement assay. Surface plasmon resonance studies demonstrated the thrombin-binding aptamer to have a lower affinity for enzyme-labeled thrombin than unmodified thrombin, with respective K(D) of 1.1 x 10(-8) and 2.9 x 10(-9) M. The assay is extremely rapid, requiring only 10 min for completion, and exhibits a detection limit lower than that obtainable with competitive enzyme-linked aptamer assays and comparable to that of hybrid aptamer-antibody assays. Optimal storage conditions for precoated microtiter plates (consisting of coated aptamer and captured

  13. The effect of environmental regulation on firms' competitive performance: the case of the building & construction sector in some EU regions.

    PubMed

    Testa, Francesco; Iraldo, Fabio; Frey, Marco

    2011-09-01

    There is a considerable debate on the effects of environmental regulation on competitive performance. Based on survey data, this paper analyzes the two main research questions, derived from literature, on the links between environmental regulation and competitiveness, by focusing on firms operating in the building and construction sector, i.e.: 1) whether environmental policy stringency affects the competitive performance of firms in the building and construction sector 2) and how a specific form of environmental regulation (direct regulation, economic instruments and soft instruments) affects this performance? By applying a regression analysis, we find that a more stringent environmental regulation, measured by inspection frequency, provides a positive impulse for increasing investments in advanced technological equipment and innovative products and on business performance. Moreover, a well-designed "direct regulation" appears to be the most effective policy instrument for prompting the positive impact of environmental policies on innovation and intangible performance while economic instruments do negatively affect business performance. PMID:21524840

  14. Regulation, Competition and Network Evolution in Aviation

    NASA Technical Reports Server (NTRS)

    Gillen, David; Morrison, William

    2003-01-01

    Our focus is the evolution of business strategies and network structure decisions in the commercial passenger aviation industry. The paper reviews the growth of hub-and-spoke networks as the dominant business model following deregulation in the latter part of the 20 century, followed by the emergence of value-based airlines as a global phenomenon at the end of the century. The paper highlights the link between airline business strategies and network structures, and examines the resulting competition between divergent network structure business models. In this context we discuss issues of market structure stability and the role played by competition policy.

  15. Impact of grazing and life forms interactions on plant communities in arid areas

    NASA Astrophysics Data System (ADS)

    Alhamad, Mohammad Noor

    2015-04-01

    Middle Eastern Mediterranean grasslands have evolved 8000-9000 years before present (BP). These grasslands were prehistorically subject to persistent pressure from grazing domesticated animals. Grazing and competition are the central factors affecting grassland communities, linking their maintenance, productivity, and management to biodiversity and livestock production. Arid and semi-arid Mediterranean grassland is a rich source of valuable forages for grazing livestock production systems in the eastern part of the Mediterranean region. Competition treatments (absence/presence of neighbors) were combined with three defoliation ( as surrogate to grazing) intensities (0%, 30% and 60%) in a factorial design. Relative interaction index (RII) was used to measure competition intensity. RII standardizes the reduction in growth of one species due to presence of neighbor species. Competition reduced grass biomass by approximately 10-15% for final and cumulative biomass. Competition role was eliminated under heavy defoliation or under harsh environmental conditions. Defoliation showed variable results on final and cumulative biomass. While heavy defoliation (60% clipping intensity) greatly reduced final grass biomass, light-moderate defoliation (30%) has increased cumulative biomass. Results showed that competition may limit the direct effect of defoliation on dominant grass species. Further, competition effect on dominant annual grasses showed positive and negative effects in relation to site productivity and best explained by a sinusoidal model. This hypothesized sinusoidal model suggests that facilitation and competition are alternatively affecting grassland communities along productivity gradient. The nature of interaction changes with changing community productivity revealing a cyclic pattern. The reflection points where interaction switches from facilitation to competition may explain the mechanism of maintaining high species diversity at intermediate level of

  16. Competitiveness, Technology and Skills.

    ERIC Educational Resources Information Center

    Lall, Sanjaya

    This document examines competitiveness in the developing world. Chapters 1 through 3, which are largely conceptual, examine the following topics: the concept of competitiveness and why it is important; market-stimulating technology policies in developing countries, and the relationship between import liberalization and industrial performance.…

  17. Competition in Economic Theory.

    ERIC Educational Resources Information Center

    Livesey, F.

    1982-01-01

    Considers two alternative views of competition found in the economics literature. The author demonstrates that these alternative views of competition underlie alternative views in other areas of economics, including welfare economics and micro-economic policy. Implications for college students and teachers are examined. (Author/AM)

  18. Competition: Was Kohn Right?

    ERIC Educational Resources Information Center

    Shields, David Light; Bredemeier, Brenda Light

    2010-01-01

    Alfie Kohn made the case for competition being destructive to education. The truth may be that there are two separate ways to contest: true competition, which is a healthy desire to excel, and decompetition, which is the unhealthy desire merely to beat the opponent. Decompetition leads to the ills that Kohn enumerated. Educators should teach their…

  19. Matrix models for quantifying competitive intransitivity

    PubMed Central

    Ulrich, Werner; Soliveres, Santiago; Kryszewski, Wojciech; Maestre, Fernando T.; Gotelli, Nicholas J.

    2015-01-01

    Assessing the relative importance of intransitive competition networks in nature has been difficult because it requires a large number of pairwise competition experiments linked to observed field abundances of interacting species. Here we introduce metrics and statistical tests for evaluating the contribution of intransitivity to community structure using two kinds of data: competition matrices derived from the outcomes of pairwise experimental studies (C matrices) and species abundance matrices. We use C matrices to develop patch transition matrices (P) that predict community structure in a simple Markov chain model. We propose a randomization test to evaluate the degree of intransitivity from these P matrices in combination with empirical or simulated C matrices. Benchmark tests revealed that the methods could correctly detect intransitive competition networks, even in the absence of direct measures of pairwise competitive strength. These tests represent the first tools for estimating the degree of intransitivity in competitive networks from observational datasets. They can be applied to both spatio-temporal data sampled in homogeneous environments or across environmental gradients, and to experimental measures of pairwise interactions. To illustrate the methods, we analyzed empirical data matrices on the colonization of slug carrion by necrophagous flies and their parasitoids. PMID:25914427

  20. Virtual Rural Community Development: Human Links That Sustain Web Links.

    ERIC Educational Resources Information Center

    Bright, Larry K.; Evans, Wayne H.; Marmet, Kathy

    Outmigration in the rural Upper Midwest prompted a group of citizens and University of South Dakota faculty to form the Center for the Advancement of Rural Communities (ARC). ARC considers how to stimulate traditionally competitive and isolated South Dakota peoples to collaborate for economic, social, educational, political, and cultural gains. As…

  1. Competition promotes the persistence of populations in ecosystems.

    PubMed

    Wang, Tao; Duan, Jinqiao; Liu, Tong

    2016-01-01

    Competition is one of the most common form in ecological systems, which plays important roles in population dynamics. However, the influences of competition on persistence of populations remain unclear when space effect is included. In this paper, we investigated a predator-prey model with competition and spatial diffusion. Based on pattern formations and time series of populations, we found that competitions induce the persistence of populations, which denies competitive exclusion principle. Moreover, we testify the robustness of these effects. Our results also suggest that space may lead to the emergence of new phenomenon in ecosystems. PMID:27460143

  2. Competition promotes the persistence of populations in ecosystems

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Duan, Jinqiao; Liu, Tong

    2016-07-01

    Competition is one of the most common form in ecological systems, which plays important roles in population dynamics. However, the influences of competition on persistence of populations remain unclear when space effect is included. In this paper, we investigated a predator-prey model with competition and spatial diffusion. Based on pattern formations and time series of populations, we found that competitions induce the persistence of populations, which denies competitive exclusion principle. Moreover, we testify the robustness of these effects. Our results also suggest that space may lead to the emergence of new phenomenon in ecosystems.

  3. Competition promotes the persistence of populations in ecosystems

    PubMed Central

    Wang, Tao; Duan, Jinqiao; Liu, Tong

    2016-01-01

    Competition is one of the most common form in ecological systems, which plays important roles in population dynamics. However, the influences of competition on persistence of populations remain unclear when space effect is included. In this paper, we investigated a predator-prey model with competition and spatial diffusion. Based on pattern formations and time series of populations, we found that competitions induce the persistence of populations, which denies competitive exclusion principle. Moreover, we testify the robustness of these effects. Our results also suggest that space may lead to the emergence of new phenomenon in ecosystems. PMID:27460143

  4. 46 CFR 282.10 - Basis for determining foreign-flag competition.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Basis for determining foreign-flag competition. 282.10... SERVICES IN THE FOREIGN COMMERCE OF THE UNITED STATES Foreign-Flag Competition § 282.10 Basis for determining foreign-flag competition. The foreign-flag competition shall form the basis for determining...

  5. 46 CFR 282.10 - Basis for determining foreign-flag competition.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Basis for determining foreign-flag competition. 282.10... SERVICES IN THE FOREIGN COMMERCE OF THE UNITED STATES Foreign-Flag Competition § 282.10 Basis for determining foreign-flag competition. The foreign-flag competition shall form the basis for determining...

  6. Increased competition may promote species coexistence.

    PubMed

    Vandermeer, J; Evans, M A; Foster, P; Höök, T; Reiskind, M; Wund, M

    2002-06-25

    It is a mainstay of community ecology that local exclusion of species will result if competitive pressures become too large. The pattern of exclusion may be complicated, but the qualitative orthodoxy has changed little since the pioneering work of Lotka, Volterra, and Gause--no two species can occupy the same niche. Stated in a more precise form, the higher the intensity of interspecific competition in an assemblage of species, the fewer the number of species that can coexist in perpetuity. We suggest that this orthodoxy results from "linear" thinking, and that if the classical equations are formulated more realistically with attendant nonlinearities, the orthodoxy breaks down and higher levels of competition may actually increase the likelihood that species will avoid competitive exclusion. Furthermore, this increased probability of coexistence at higher levels of competition is accompanied by characteristic dynamic patterns: (i) at lower levels of competition, after all extinction events have occurred, remaining species follow irregular chaotic patterns; (ii) at higher levels of competition, when most species coexist, all species are entrained in a single large limit cycle; (iii) the transient behavior appears to correspond to a special case of chaos, uniform phase chaotic amplitude.

  7. Potential Competitive Dynamics of Acoustic Ecology.

    PubMed

    Radford, C A; Montgomery, J C

    2016-01-01

    The top predators in coastal marine ecosystems, such as whales, dolphins, seabirds, and large predatory fishes (including sharks), may compete with each other to exploit food aggregations. Finding these patchy food sources and being first to a food patch could provide a significant competitive advantage. Our hypothesis is that food patches have specific sound signatures that marine predators could detect and that acoustic sources and animal sensory capabilities may contribute to competition dynamics. Preliminary analysis shows that diving gannets have a distinct spectral signature between 80 and 200 Hz, which falls within the hearing sensitivity of large pelagic fishes. Therefore, we suggest that diving birds may contribute to the sound signatures of food aggregations, linking competition dynamics both above and below the water surface.

  8. Potential Competitive Dynamics of Acoustic Ecology.

    PubMed

    Radford, C A; Montgomery, J C

    2016-01-01

    The top predators in coastal marine ecosystems, such as whales, dolphins, seabirds, and large predatory fishes (including sharks), may compete with each other to exploit food aggregations. Finding these patchy food sources and being first to a food patch could provide a significant competitive advantage. Our hypothesis is that food patches have specific sound signatures that marine predators could detect and that acoustic sources and animal sensory capabilities may contribute to competition dynamics. Preliminary analysis shows that diving gannets have a distinct spectral signature between 80 and 200 Hz, which falls within the hearing sensitivity of large pelagic fishes. Therefore, we suggest that diving birds may contribute to the sound signatures of food aggregations, linking competition dynamics both above and below the water surface. PMID:26611047

  9. Climate influences parasite-mediated competitive release.

    PubMed

    Larsen, Martin H; Jensen, K Thomas; Mouritsen, Kim N

    2011-09-01

    Parasitism is believed to play an important role in maintaining species diversity, for instance by facilitating coexistence between competing host species. However, the possibility that environmental factors may govern the outcome of parasite-mediated competition has rarely been considered. The closely related amphipods Corophium volutator and Corophium arenarium both serve as second intermediate host for detrimental trematodes. Corophium volutator is the superior competitor of the two, but also suffers from higher mortality when exposed to infective trematode stages. Here, we report parasite-mediated competitive release of C. arenarium in an intertidal habitat, in part triggered by unusually high temperatures linked to the North Atlantic climate oscillation (NAO). The elevated temperatures accelerated the transmission of cercariae from sympatric first intermediate hosts (mud snails) to amphipods, causing a local collapse of the parasite-sensitive C. volutator population and concordant increase in the abundance of the competitively inferior C. arenarium.

  10. Costing and competition.

    PubMed

    Bates, K; Brignall, S

    1994-01-01

    Working for patients established a new system of contracts between providers and purchasers of healthcare, with prices based on full costs, avoiding cross-subsidization. The new regime necessitates greatly improved costing systems, to improve the efficiency of service provision by creating price competition between providers. Ken Bates and Stan Brignall argue that non-price competition also occurs, with providers 'differentiating' on quality of service/product, flexibility or innovation. PMID:10136091

  11. 2000 FIRST Robotics Competition

    NASA Technical Reports Server (NTRS)

    Purman, Richard

    2000-01-01

    The New Horizons Regional Education Center (NHREC) in Hampton, VA sought and received NASA funding to support its participation in the 2000 FIRST Robotics competition. FIRST, Inc. (For Inspiration and Recognition of Science and Technology) is an organization which encourages the application of creative science, math, and computer science principles to solve real-world engineering problems. The FIRST competition is an international engineering contest featuring high school, government, and business partnerships.

  12. Untangling healthcare competition.

    PubMed

    Harris, I C; McDaniel, R R

    1993-11-01

    Traditional approaches to competition may be inappropriate for healthcare providers. Neoclassical economics makes the implicit assumption that a single actor embodies consumption, compensation, and benefit from a transaction. In healthcare, this assumption does not hold. Instead, such actions are accomplished by three separate actors--consumers (physicians), customers (third-party payers), and clients (patients). A hospital simultaneously competes in three arenas. Hospitals compete for physicians along a technological dimension. Competition for third-party payers takes on a financial dimension. Hospitals compete for patients along a marketing dimension. Because of the complex marketplace interactions among hospital, patient, physician, and third-party payer, the role of price in controlling behavior is difficult to establish. The dynamics underlying the hospital selection decision--that is, the decision maker's expectations of services and the convenience of accessing services--must also be considered. Healthcare managers must understand the interrelationships involved in the three-pronged competitive perspective for several reasons. This perspective clarifies the multiple facets of competition a hospital faces. It also disentangles the actions previously fulfilled by the traditional single buyer. It illuminates the critical skills underlying the competition for each audience. Finally, it defines the primary criterion each audience uses in sorting among hospitals. Recognition of the multifaceted nature of competition among healthcare providers will help demystify market behavior and thereby improve internal organizational communication systems, managers' ability to focus on appropriate activities, and the hospital's ability to adapt to changing market conditions.

  13. Competition for land

    PubMed Central

    Smith, Pete; Gregory, Peter J.; van Vuuren, Detlef; Obersteiner, Michael; Havlík, Petr; Rounsevell, Mark; Woods, Jeremy; Stehfest, Elke; Bellarby, Jessica

    2010-01-01

    A key challenge for humanity is how a future global population of 9 billion can all be fed healthily and sustainably. Here, we review how competition for land is influenced by other drivers and pressures, examine land-use change over the past 20 years and consider future changes over the next 40 years. Competition for land, in itself, is not a driver affecting food and farming in the future, but is an emergent property of other drivers and pressures. Modelling studies suggest that future policy decisions in the agriculture, forestry, energy and conservation sectors could have profound effects, with different demands for land to supply multiple ecosystem services usually intensifying competition for land in the future. In addition to policies addressing agriculture and food production, further policies addressing the primary drivers of competition for land (population growth, dietary preference, protected areas, forest policy) could have significant impacts in reducing competition for land. Technologies for increasing per-area productivity of agricultural land will also be necessary. Key uncertainties in our projections of competition for land in the future relate predominantly to uncertainties in the drivers and pressures within the scenarios, in the models and data used in the projections and in the policy interventions assumed to affect the drivers and pressures in the future. PMID:20713395

  14. Sexual Selection on male cuticular hydrocarbons via male-male competition and female choice.

    PubMed

    Lane, S M; Dickinson, A W; Tregenza, T; House, C M

    2016-07-01

    Traditional views of sexual selection assumed that male-male competition and female mate choice work in harmony, selecting upon the same traits in the same direction. However, we now know that this is not always the case and that these two mechanisms often impose conflicting selection on male sexual traits. Cuticular hydrocarbons (CHCs) have been shown to be linked to both social dominance and male attractiveness in several insect species. However, although several studies have estimated the strength and form of sexual selection imposed on male CHCs by female mate choice, none have established whether these chemical traits are also subject to sexual selection via male-male competition. Using a multivariate selection analysis, we estimate and compare sexual selection exerted by male-male competition and female mate choice on male CHC composition in the broad-horned flour beetle Gnatocerus cornutus. We show that male-male competition exerts strong linear selection on both overall CHC abundance and body size in males, while female mate choice exerts a mixture of linear and nonlinear selection, targeting not just the overall amount of CHCs expressed but the relative abundance of specific hydrocarbons as well. We discuss the potential implications of this antagonistic selection with regard to male reproductive success.

  15. Sexual Selection on male cuticular hydrocarbons via male-male competition and female choice.

    PubMed

    Lane, S M; Dickinson, A W; Tregenza, T; House, C M

    2016-07-01

    Traditional views of sexual selection assumed that male-male competition and female mate choice work in harmony, selecting upon the same traits in the same direction. However, we now know that this is not always the case and that these two mechanisms often impose conflicting selection on male sexual traits. Cuticular hydrocarbons (CHCs) have been shown to be linked to both social dominance and male attractiveness in several insect species. However, although several studies have estimated the strength and form of sexual selection imposed on male CHCs by female mate choice, none have established whether these chemical traits are also subject to sexual selection via male-male competition. Using a multivariate selection analysis, we estimate and compare sexual selection exerted by male-male competition and female mate choice on male CHC composition in the broad-horned flour beetle Gnatocerus cornutus. We show that male-male competition exerts strong linear selection on both overall CHC abundance and body size in males, while female mate choice exerts a mixture of linear and nonlinear selection, targeting not just the overall amount of CHCs expressed but the relative abundance of specific hydrocarbons as well. We discuss the potential implications of this antagonistic selection with regard to male reproductive success. PMID:27037514

  16. Environmental stress, facilitation, competition, and coexistence.

    PubMed

    Hart, Simon P; Marshall, Dustin J

    2013-12-01

    The major theories regarding the combined influence of the environment and species interactions on population and community dynamics appear to conflict. Stress/ disturbance gradient models of community organization, such as the stress gradient hypothesis, emphasize a diminished role for competition in harsh environments whereas modern coexistence theory does not. Confusion about the role of species interactions in harsh environments is perpetuated by a disconnect between population dynamics theory and data. We linked theory and data using response surface experiments done in the field to parameterize mathematical, population-dynamic competition models. We replicated our experiment across two environments that spanned a common and important environmental stress gradient for determining community structure in benthic marine systems. We generated quantitative estimates of the effects of environmental stress on population growth rates and the direction and strength of intra- and interspecific interactions within each environment. Our approach directly addressed a perpetual blind spot in this field by showing how the effects of competition can be intensified in stressful environments even though the apparent strength of competition remains unchanged. Furthermore, we showed how simultaneous, reciprocal competitive and facilitative effects can stabilize population dynamics in multispecies communities in stressful environments.

  17. Environmental stress, facilitation, competition, and coexistence.

    PubMed

    Hart, Simon P; Marshall, Dustin J

    2013-12-01

    The major theories regarding the combined influence of the environment and species interactions on population and community dynamics appear to conflict. Stress/ disturbance gradient models of community organization, such as the stress gradient hypothesis, emphasize a diminished role for competition in harsh environments whereas modern coexistence theory does not. Confusion about the role of species interactions in harsh environments is perpetuated by a disconnect between population dynamics theory and data. We linked theory and data using response surface experiments done in the field to parameterize mathematical, population-dynamic competition models. We replicated our experiment across two environments that spanned a common and important environmental stress gradient for determining community structure in benthic marine systems. We generated quantitative estimates of the effects of environmental stress on population growth rates and the direction and strength of intra- and interspecific interactions within each environment. Our approach directly addressed a perpetual blind spot in this field by showing how the effects of competition can be intensified in stressful environments even though the apparent strength of competition remains unchanged. Furthermore, we showed how simultaneous, reciprocal competitive and facilitative effects can stabilize population dynamics in multispecies communities in stressful environments. PMID:24597219

  18. Healthy Competition and Unsound Comparison: Reforming Educational Competition in Singapore

    ERIC Educational Resources Information Center

    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…

  19. Price competition in procurement

    SciTech Connect

    Keisler, J.M.; Buehring, W.A.

    1996-07-01

    When creating a private market to provide a public good, government agencies can influence the market`s competitive characteristics. Markets have predictable, but often counterintuitive, behaviors. To succeed in applying available controls, and thereby reduce future costs, agencies must understand the behavior of the market. A model has been constructed to examine some issues in establishing competition for a structure in which there are economies of scale and government is obligated to purchase a fixed total quantity of a good. This model is used to demonstrate a way to estimate the cost savings from several alternative plans for a buyer exploring competitive procurement. The results are not and cannot be accurate for budgeting purposes; rather, they indicate the approximate magnitude of changes in cost that would be associated with changes in the market structure within which procurement occurs.

  20. Competitive hybridization models

    NASA Astrophysics Data System (ADS)

    Cherepinsky, Vera; Hashmi, Ghazala; Mishra, Bud

    2010-11-01

    Microarray technology, in its simplest form, allows one to gather abundance data for target DNA molecules, associated with genomes or gene-expressions, and relies on hybridizing the target to many short probe oligonucleotides arrayed on a surface. While for such multiplexed reactions conditions are optimized to make the most of each individual probe-target interaction, subsequent analysis of these experiments is based on the implicit assumption that a given experiment yields the same result regardless of whether it was conducted in isolation or in parallel with many others. It has been discussed in the literature that this assumption is frequently false, and its validity depends on the types of probes and their interactions with each other. We present a detailed physical model of hybridization as a means of understanding probe interactions in a multiplexed reaction. Ultimately, the model can be derived from a system of ordinary differential equations (ODE’s) describing kinetic mass action with conservation-of-mass equations completing the system. We examine pairwise probe interactions in detail and present a model of “competition” between the probes for the target—especially, when the target is effectively in short supply. These effects are shown to be predictable from the affinity constants for each of the four probe sequences involved, namely, the match and mismatch sequences for both probes. These affinity constants are calculated from the thermodynamic parameters such as the free energy of hybridization, which are in turn computed according to the nearest neighbor (NN) model for each probe and target sequence. Simulations based on the competitive hybridization model explain the observed variability in the signal of a given probe when measured in parallel with different groupings of other probes or individually. The results of the simulations can be used for experiment design and pooling strategies, based on which probes have been shown to have a strong

  1. Utility competition and residential customers

    SciTech Connect

    Studness, C.M.

    1994-11-01

    Residential customers have found themselves either ignored or ill-used by the major participants in the struggle over utility competition. No group is seeking to secure them the benefits of competition, and those who oppose competition have curried their favor by conjuring up misleading horror stories about how competition would harm them. Yet residential customers ultimately stand to gain as much from competition as larger customers.

  2. Advancing Manufacturing Research Through Competitions

    SciTech Connect

    Balakirsky, Stephen; Madhavan, Raj

    2009-01-01

    Competitions provide a technique for building interest and collaboration in targeted research areas. This paper will present a new competition that aims to increase collaboration amongst Universities, automation end-users, and automation manufacturers through a virtual competition. The virtual nature of the competition allows for reduced infrastructure requirements while maintaining realism in both the robotic equipment deployed and the scenarios. Details of the virtual environment as well as the competitions objectives, rules, and scoring metrics will be presented.

  3. Competitive Speech and Debate: How Play Influenced American Educational Practice

    ERIC Educational Resources Information Center

    Bartanen, Michael D.; Littlefield, Robert S.

    2015-01-01

    The authors identify competitive speech and debate as a form of play that helped democratize American citizenship for the poor, who used what they learned through the practice to advance their personal social and economic goals. In addition, this competitive activity led to the development of speech communication as an academic discipline and…

  4. Competition for water among plants: resolving the root system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Competition for water and nutrients by plants plays a major role in controlling the level of reactive forms of nutrients and their availability for off-site leakage. The processes controlling competition are, however, poorly understood and quantified. The goal of this research is to unravel the me...

  5. "Conjectural" links in complex networks

    NASA Astrophysics Data System (ADS)

    Snarskii, A. A.; Zorinets, D. I.; Lande, D. V.

    2016-11-01

    This paper introduces the concept of Conjectural Link for Complex Networks, in particular, social networks. Conjectural Link we understand as an implicit link, not available in the network, but supposed to be present, based on the characteristics of its topology. It is possible, for example, when in the formal description of the network some connections are skipped due to errors, deliberately hidden or withdrawn (e.g. in the case of partial destruction of the network). Introduced a parameter that allows ranking the Conjectural Link. The more this parameter - the more likely that this connection should be present in the network. This paper presents a method of recovery of partially destroyed Complex Networks using Conjectural Links finding. Presented two methods of finding the node pairs that are not linked directly to one another, but have a great possibility of Conjectural Link communication among themselves: a method based on the determination of the resistance between two nodes, and method based on the computation of the lengths of routes between two nodes. Several examples of real networks are reviewed and performed a comparison to know network links prediction methods, not intended to find the missing links in already formed networks.

  6. Sex-linked dominant

    MedlinePlus

    Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant ... can be either an autosomal chromosome or a sex chromosome. It also depends on whether the trait ...

  7. Competition in benthic marine invertebrates: the unrecognized role of exploitative competition for oxygen.

    PubMed

    Ferguson, Nick; White, Craig R; Marshall, Dustin J

    2013-01-01

    Competition is a ubiquitous structuring force across systems, but different fields emphasize the role of different types of competition. In benthic marine environments, where some of the classic examples of competition were described, there is a strong emphasis on interference competition: marine invertebrates are assumed to compete fiercely for the limiting resource of space. Much of our understanding of the dynamics of this system is based on this assumption, yet empirical studies often find that increases in density can reduce performance despite free space being available. Furthermore, the assumption that space is the exclusively limiting resource raises paradoxes regarding species coexistence in this system. Here, we measure the availability of oxygen in the field and in the laboratory, as well as the tolerance of resident species to low-oxygen conditions. We show that oxygen can be the primary limiting resource in some instances, and that exploitative competition for this resource is very likely among benthic marine invertebrates. Furthermore, growth form (and the associated risk of oxygen limitation) covaries with the ability to withstand oxygen-poor conditions across a wide range of taxa. Oxygen availability at very small scales may influence the distribution and abundance of sessile marine invertebrates more than is currently appreciated. Furthermore, competition for multiple resources (space and oxygen) and trade-offs in competitive ability for each may promote coexistence in this system.

  8. Competition in the Classroom.

    ERIC Educational Resources Information Center

    Napier, Erv

    1981-01-01

    Argues that teacher use of competition in the classroom may lead to anxiety, aggression, or a decrease in self-concept among students and that learning to compete is not so important in a postindustrial society. Advocates cooperative classroom activities. (SJL)

  9. Cost and competition

    SciTech Connect

    Kahn, E.

    1994-11-01

    The growth of private power is part of the movement away from administrative regulation and toward competitive control of prices for electricity. Despite the substantial success of the private power industry, this process is far from complete. Utility regulators, who preside over the power purchase contracting process, are responsible for assuring that the prices which are presented to them for approval are reasonable.

  10. Competition in the Classroom

    ERIC Educational Resources Information Center

    Jameson, Daphne

    2007-01-01

    In this article, the author shares the strategy she adopted to even out the participation among her multicultural students during their classroom discussions. The author realized that her students had different concepts about the classroom and different philosophies about competition. For the Americans and Indians, the classroom was a site of…

  11. Reed Hundt's Friendly Competition.

    ERIC Educational Resources Information Center

    Educom Review, 1996

    1996-01-01

    Presents an interview with Reed Hundt, Chairman of the Federal Communications Commission (FCC), who implemented the Education Task Force to coordinate the FCC's role in educational provisions of the Telecommunications Act of 1996. He asserts that writing clear rules for the communications sector will promote competition and ensure educational…

  12. Building Camaraderie from Competition

    ERIC Educational Resources Information Center

    Marino, Gordon

    2007-01-01

    Educational institutions have adopted athletics programs to promote character building. Sports help people feel comfortable in their skins and provide unique opportunities to develop qualities such as cooperation, perseverance, and the ability to cope with fear. But the arena can be a hothouse for more primal feelings that emerge in competition.…

  13. Competitiveness and Campaign '88.

    ERIC Educational Resources Information Center

    Kernan-Schloss, Adam, Ed.; And Others

    This report profiles the positions of the six Democratic and six Republican 1988 presidential candidates on policy issues affecting U.S. competitiveness in the global economy. Candidate profiles are provided for: Bruce Babbitt, Michael Dukakis, Richard Gephardt, Albert Gore, Jr., Jesse Jackson, and Paul Simon (Democrats); and George Bush, Robert…

  14. Human Resources Competitiveness Profile.

    ERIC Educational Resources Information Center

    Council on Competitiveness, Washington, DC.

    This report distills hundreds of indicators from both domestic and international sources to determine how the United States compares to other countries and to its own past performance in competitiveness. It attempts to establish a baseline of some key education and training indicators that, taken together, show where the nation stands and where it…

  15. Growing Competition for Libraries.

    ERIC Educational Resources Information Center

    Gibbons, Susan

    2001-01-01

    Describes the Questia subscription-based online academic digital books library. Highlights include weaknesses of the collection; what college students want from a library; importance of marketing; competition for traditional academic libraries that may help improve library services; and the ability of Questia to overcome barriers and…

  16. Positioning for Competition.

    ERIC Educational Resources Information Center

    Lapovsky, Lucie; Hubbell, Loren Loomis

    2000-01-01

    Analyzes results of the 1999 National Association of College and Business Officers tuition discounting survey and identifies trends. Finds colleges and universities are reactively responding to market pressures and proactively trying to analyze and position themselves ahead of the competition, often regional rather than national, for the…

  17. A Winning Competition

    ERIC Educational Resources Information Center

    Geddes, Kim; Franchini, Elease

    2012-01-01

    As a high school physics teacher, Kim Geddes is constantly searching for new experiences to challenge, motivate, and engage students. Last year, she incorporated ExploraVision into the energy unit of her school's physics curriculum with the help of their media specialist (Elease Franchini). ExploraVision is a competition offered through a…

  18. Competitiveness Index 1990.

    ERIC Educational Resources Information Center

    Council on Competitiveness, Washington, DC.

    The United States' economic performance in the world economy is compared with that of Canada, France, Germany, Italy, Japan, and the United Kingdom (the Summit 7 countries). Competitiveness is assessed by four economic indicators: standard of living, trade, manufacturing productivity, and investment. The United States continues to outinvest the…

  19. Competition asymmetry with taxon divergence.

    PubMed

    Barnes, David K A

    2003-03-22

    Most organisms experience competition for resources, probably most of the time. As the structure and requirements of closely related species are generally liable to be more similar than in distantly linked species, Darwin suggested that the potential for competition was greater in the former. Since that time, studies have concentrated on interactions of either conspecifics or congeneric species. Shared critical resources, which organisms compete for, are generally mates, food and space (for access to the former). Whilst mates are valued only within species, in that the definition of a species requires it so, both food and space have the potential to be shared by very different organisms. It is now clear that vertebrates may compete with remotely related species: e.g. with squid for krill and with insects for nectar or seeds. Diamond suggested that (i) mutual aggression, (ii) displacement and (iii) evolutionary change in morphology would be increasingly asymmetric with competitor dissimilarity. Thus, with increasing taxonomic distance between two competitors (A and B), increasing aggression is exhibited between them and, increasingly, one consistently displaces the other. Here, Darwin's suggestion and Diamond's first two theories are tested across a taxonomic spectrum for the first time to the best of the author's knowledge. The proportion of spatial competitors in two different marine invertebrate groups demonstrating mutual aggression and displacement increases with taxon divergence (Nei's genetic identity). Congenerics were twice as likely to fight as conspecifics, and confamilial competitors were three times as likely to fight as conspecifics. This relationship seems robust to taxonomic and environmental variability. Competitors do not need to be as distant as birds and bees for complete asymmetry, a different family seems sufficient.

  20. Cellular Defect May Be Linked to Parkinson's

    MedlinePlus

    ... 160862.html Cellular Defect May Be Linked to Parkinson's: Study Abnormality might apply to all forms of ... that may be common to all forms of Parkinson's disease. The defect plays a major role in ...

  1. Environmental structure and competitive scoring advantages in team competitions.

    PubMed

    Merritt, Sears; Clauset, Aaron

    2013-10-29

    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.

  2. Environmental structure and competitive scoring advantages in team competitions

    NASA Astrophysics Data System (ADS)

    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.

  3. Competitive aggregation dynamics using phase wave signals.

    PubMed

    Sakaguchi, Hidetsugu; Maeyama, Satomi

    2014-10-21

    Coupled equations of the phase equation and the equation of cell concentration n are proposed for competitive aggregation dynamics of slime mold in two dimensions. Phase waves are used as tactic signals of aggregation in this model. Several aggregation clusters are formed initially, and target patterns appear around the localized aggregation clusters. Owing to the competition among target patterns, the number of the localized aggregation clusters decreases, and finally one dominant localized pattern survives. If the phase equation is replaced with the complex Ginzburg-Landau equation, several spiral patterns appear, and n is localized near the center of the spiral patterns. After the competition among spiral patterns, one dominant spiral survives. PMID:24956327

  4. Modeling share dynamics by extracting competition structure

    NASA Astrophysics Data System (ADS)

    Kimura, Masahiro; Saito, Kazumi; Ueda, Naonori

    2004-11-01

    We propose a new method for analyzing multivariate time-series data governed by competitive dynamics such as fluctuations in the number of visitors to Web sites that form a market. To achieve this aim, we construct a probabilistic dynamical model using a replicator equation and derive its learning algorithm. This method is implemented for both categorizing the sites into groups of competitors and predicting the future shares of the sites based on the observed time-series data. We confirmed experimentally, using synthetic data, that the method successfully identifies the true model structure, and exhibits better prediction performance than conventional methods that leave competitive dynamics out of consideration. We also experimentally demonstrated, using real data of visitors to 20 Web sites offering streaming video contents, that the method suggested a reasonable competition structure that conventional methods failed to find and that it outperformed them in terms of predictive performance.

  5. Competitiveness measurement system in the advertising sector.

    PubMed

    Poveda-Bautista, Rocío; García-Melón, Mónica; Baptista, Doris C

    2013-01-01

    In this paper a new approach to find indicators that can be used to measure companies' competitiveness and performance in an efficient and reliable way is presented. The aim is to assist managers of companies within a specific industrial sector by providing information about their relative position in the market so as to define better action plans that may improve the company's performance. The approach combines the use of the Analytic Network Process, a multicriteria decision method, with the Balanced Scorecard. It allows the definition of a number of competitiveness indicators based on the performance and setting of the advertising sector. In this way it is possible to obtain a Competitiveness Index that allows a company to know its relative position with respect to other companies in the sector, and establish a ranking of the companies ordered by their competitiveness level. A case study in the advertising industry of Venezuela is provided. Results show that improvement plans for the agencies analyzed should promote creativity, innovation and the use of new technologies, as a particular form of innovation. These factors were considered to be the most relevant indicators in the advertising sector. The participating experts agreed that the methodology is useful and an improvement over current competitiveness assessment methods.

  6. Competitiveness measurement system in the advertising sector.

    PubMed

    Poveda-Bautista, Rocío; García-Melón, Mónica; Baptista, Doris C

    2013-01-01

    In this paper a new approach to find indicators that can be used to measure companies' competitiveness and performance in an efficient and reliable way is presented. The aim is to assist managers of companies within a specific industrial sector by providing information about their relative position in the market so as to define better action plans that may improve the company's performance. The approach combines the use of the Analytic Network Process, a multicriteria decision method, with the Balanced Scorecard. It allows the definition of a number of competitiveness indicators based on the performance and setting of the advertising sector. In this way it is possible to obtain a Competitiveness Index that allows a company to know its relative position with respect to other companies in the sector, and establish a ranking of the companies ordered by their competitiveness level. A case study in the advertising industry of Venezuela is provided. Results show that improvement plans for the agencies analyzed should promote creativity, innovation and the use of new technologies, as a particular form of innovation. These factors were considered to be the most relevant indicators in the advertising sector. The participating experts agreed that the methodology is useful and an improvement over current competitiveness assessment methods. PMID:24505555

  7. Energy's role in competitiveness: Context and strategy

    SciTech Connect

    Roop, J.M.

    1990-02-01

    This study of competitiveness has three objectives. The first objective is to explain how macroeconomic and microeconomic factors can affect structural change in the US economy and how energy is linked to these factors. The second objective is to provide an explanation of how many individual decision makers, in responding to higher energy prices, have changed the structure of the economy. This structural change, and the effect it has had on energy use, is estimated for the US economy. A major component of these changes results from changes in US trade with other countries, which gives rise to the third objective. The third objective is to develop a research design that will allow a better understanding of the role that energy plays in the competitiveness of goods in world trade. 30 refs., 11 figs., 5 tabs.

  8. The Literature of Competitive Intelligence.

    ERIC Educational Resources Information Center

    Walker, Thomas D.

    1994-01-01

    Describes competitive intelligence (CI) literature in terms of its location, quantity, authorship, length, and problems of bibliographic access. Highlights include subject access; competitive intelligence research; espionage and security; monographs; and journals. (21 references) (LRW)

  9. Competition for finite resources

    NASA Astrophysics Data System (ADS)

    Cook, L. Jonathan; Zia, R. K. P.

    2012-05-01

    The resources in a cell are finite, which implies that the various components of the cell must compete for resources. One such resource is the ribosomes used during translation to create proteins. Motivated by this example, we explore this competition by connecting two totally asymmetric simple exclusion processes (TASEPs) to a finite pool of particles. Expanding on our previous work, we focus on the effects on the density and current of having different entry and exit rates.

  10. Competitive Intelligence and Social Advantage.

    ERIC Educational Resources Information Center

    Davenport, Elisabeth; Cronin, Blaise

    1994-01-01

    Presents an overview of issues concerning civilian competitive intelligence (CI). Topics discussed include competitive advantage in academic and research environments; public domain information and libraries; covert and overt competitive intelligence; data diversity; use of the Internet; cooperative intelligence; and implications for library and…

  11. Hospital survival in a competitive environment: the competitive constituency model.

    PubMed

    Ehreth, J

    1993-01-01

    Organizational theory is extended to develop a method for administrators to assess hospital effectiveness in a competitive environment. First, the literature pertaining to organizational effectiveness and survival is synthesized to show the lack of consideration for the effects of competition. Second, the article integrates the effects of competition on organizational effectiveness through a competitive constituency model. A step-by-step procedure is proposed to apply the theory in an organizational setting. The model explicitly addresses differences in power relations between hospitals, their competition, and their stakeholders. The relative nature of effectiveness is explored by comparing the hospital to its competition using criteria developed through specific goals of stakeholders. The distinction between managerial and organizational effectiveness constructs is clarified. Finally, the practical application of this model is demonstrated by assessing the effectiveness of a hospital in the competitive environment of Seattle, Washington, where two hospitals have recently closed.

  12. Competition between conceptual relations affects compound recognition: the role of entropy.

    PubMed

    Schmidtke, Daniel; Kuperman, Victor; Gagné, Christina L; Spalding, Thomas L

    2016-04-01

    Previous research has suggested that the conceptual representation of a compound is based on a relational structure linking the compound's constituents. Existing accounts of the visual recognition of modifier-head or noun-noun compounds posit that the process involves the selection of a relational structure out of a set of competing relational structures associated with the same compound. In this article, we employ the information-theoretic metric of entropy to gauge relational competition and investigate its effect on the visual identification of established English compounds. The data from two lexical decision megastudies indicates that greater entropy (i.e., increased competition) in a set of conceptual relations associated with a compound is associated with longer lexical decision latencies. This finding indicates that there exists competition between potential meanings associated with the same complex word form. We provide empirical support for conceptual composition during compound word processing in a model that incorporates the effect of the integration of co-activated and competing relational information. PMID:26340846

  13. The impact of competition among health care financing authorities on market yields and issuer interest expenses.

    PubMed

    Bernet, Patrick M; Carpenter, Caryl E; Saunders, Warren

    2011-01-01

    The main source of capital for non-for-profit health care organizations is tax-exempt municipal bonds. The tax-exempt nature of this debt requires that they be issued through financing authorities, which are run by, or affiliated with, state or local government agencies. In some states, all tax-exempt health care bonds must be issued through a single financing authority, but in other states the issuing health care organization has a choice of multiple authorities. Using a Herfindahl index of issuer concentration, prior research has found that greater competition among authorities results in lower interest costs to the issuing health care organization. We pick up where this earlier study left off, examining the links between authority competition, the interest expenses to the issuer, and the yield to the market investor. Although our analysis of all hospital bonds issued between 1994 and 2002 corroborates earlier findings with regard to interest expenses to the issuing health care organization, we also find market yield is lower for statewide authorities where issuer concentration is lower. Thus, authority competition is good from the issuers' point of view, but holds no favor in the investors' eyes. On the other hand, the lower market yield associated with statewide authorities does not make its way down to the issuer in the form of lower interest costs. To help sort through this paradox, we explore our findings through interviews of executives in state issuing authorities.

  14. The two sides of competition: competition-induced effort and affect during intergroup versus interindividual competition.

    PubMed

    Wittchen, Marion; Krimmel, Anna; Kohler, Mischa; Hertel, Guido

    2013-08-01

    Competition strongly affects individual effort and performance for both individuals and groups. Especially in work settings, these effort gains might come at the cost of individual well-being. The present study tested whether competition increases both effort (as indicated by task performance) and stress (in terms of cardiovascular reactivity and affective response), and whether this effect is further qualified by the type of competition (interindividual vs. intergroup), using a cognitive computer-based task and a 2 (Group: Yes, No) × 2 (Competition: Yes, No) × 2 (Gender) factorial design (N = 147). All participants either worked as a representative of a group or as an individual, and were offered performance-related incentives distributed in a lottery. In the competition conditions, participants were informed that they competed with someone else, and that only the winning person/team would take part in the lottery. Consistent with expectations, competition increased both individual effort and cardiovascular reactivity compared to non-competitive work. Moreover, for female participants, intergroup competition triggered increased effort and more positive affect than interindividual competition. Aside from documenting costly side-effects of competition in terms of stress, this study provides evidence for a stress-related explanation of effort gains during intergroup competition as compared to interindividual competition.

  15. Competitive Intelligence on the Internet-Going for the Gold.

    ERIC Educational Resources Information Center

    Kassler, Helene

    2000-01-01

    Discussion of competitive intelligence (CI) focuses on recent Web sties and several search techniques that provide valuable CI information. Highlights include links that display business relationships; information from vendors; general business sites; search engine strategies; local business newspapers; job postings; patent and trademark…

  16. Sixth-Form Colleges: An Endangered Organisational Form?

    ERIC Educational Resources Information Center

    Stoten, David William

    2014-01-01

    The sixth-form college sector is often marginalised in policy and academic discourse, where the much larger school and further education sectors dominate. This paper sets out to describe the sector's key features, assess its position within the wider education system and consider its future in an increasingly competitive education market. The…

  17. Competition improves robustness against loss of information.

    PubMed

    Kermani Kolankeh, Arash; Teichmann, Michael; Hamker, Fred H

    2015-01-01

    A substantial number of works have aimed at modeling the receptive field properties of the primary visual cortex (V1). Their evaluation criterion is usually the similarity of the model response properties to the recorded responses from biological organisms. However, as several algorithms were able to demonstrate some degree of similarity to biological data based on the existing criteria, we focus on the robustness against loss of information in the form of occlusions as an additional constraint for better understanding the algorithmic level of early vision in the brain. We try to investigate the influence of competition mechanisms on the robustness. Therefore, we compared four methods employing different competition mechanisms, namely, independent component analysis, non-negative matrix factorization with sparseness constraint, predictive coding/biased competition, and a Hebbian neural network with lateral inhibitory connections. Each of those methods is known to be capable of developing receptive fields comparable to those of V1 simple-cells. Since measuring the robustness of methods having simple-cell like receptive fields against occlusion is difficult, we measure the robustness using the classification accuracy on the MNIST hand written digit dataset. For this we trained all methods on the training set of the MNIST hand written digits dataset and tested them on a MNIST test set with different levels of occlusions. We observe that methods which employ competitive mechanisms have higher robustness against loss of information. Also the kind of the competition mechanisms plays an important role in robustness. Global feedback inhibition as employed in predictive coding/biased competition has an advantage compared to local lateral inhibition learned by an anti-Hebb rule.

  18. Rowing competitions and perspective

    NASA Astrophysics Data System (ADS)

    Flores, Alfinio; Bernhardt, Stephen A.; Shipman, Henry L.

    2015-02-01

    This paper is about integrating the use of graphing technology (specifically, GeoGebra) with principles of motion, principles of perspective, and the concept of vanishing points to model a dynamic event. Students were asked to analyse video images of a rowing competition filmed with a single camera positioned perpendicular to the race. The fixed position of the camera in such races makes it difficult to determine whether a scull closer to the camera is actually overtaking another, more distant scull. The paper illustrates how students in their first year at the university can integrate the use of technology, science, mathematics, and writing to solve a real world problem involving motion.

  19. Attention competition with advertisement

    NASA Astrophysics Data System (ADS)

    Cetin, Uzay; Bingol, Haluk O.

    2014-09-01

    In the new digital age, information is available in large quantities. Since information consumes primarily the attention of its recipients, the scarcity of attention is becoming the main limiting factor. In this study, we investigate the impact of advertisement pressure on a cultural market where consumers have a limited attention capacity. A model of competition for attention is developed and investigated analytically and by simulation. Advertisement is found to be much more effective when the attention capacity of agents is extremely scarce. We have observed that the market share of the advertised item improves if dummy items are introduced to the market while the strength of the advertisement is kept constant.

  20. Attention competition with advertisement.

    PubMed

    Cetin, Uzay; Bingol, Haluk O

    2014-09-01

    In the new digital age, information is available in large quantities. Since information consumes primarily the attention of its recipients, the scarcity of attention is becoming the main limiting factor. In this study, we investigate the impact of advertisement pressure on a cultural market where consumers have a limited attention capacity. A model of competition for attention is developed and investigated analytically and by simulation. Advertisement is found to be much more effective when the attention capacity of agents is extremely scarce. We have observed that the market share of the advertised item improves if dummy items are introduced to the market while the strength of the advertisement is kept constant. PMID:25314476

  1. Attention competition with advertisement.

    PubMed

    Cetin, Uzay; Bingol, Haluk O

    2014-09-01

    In the new digital age, information is available in large quantities. Since information consumes primarily the attention of its recipients, the scarcity of attention is becoming the main limiting factor. In this study, we investigate the impact of advertisement pressure on a cultural market where consumers have a limited attention capacity. A model of competition for attention is developed and investigated analytically and by simulation. Advertisement is found to be much more effective when the attention capacity of agents is extremely scarce. We have observed that the market share of the advertised item improves if dummy items are introduced to the market while the strength of the advertisement is kept constant.

  2. X-linked Charcot-Marie-Tooth disease, Arts syndrome, and prelingual non-syndromic deafness form a disease continuum: evidence from a family with a novel PRPS1 mutation

    PubMed Central

    2014-01-01

    Background X-linked Charcot-Marie-Tooth disease type 5 (CMTX5), Arts syndrome, and non-syndromic sensorineural deafness (DFN2) are allelic syndromes, caused by reduced activity of phosphoribosylpyrophosphate synthetase 1 (PRS-I) due to loss-of-function mutations in PRPS1. As only few families have been described, knowledge about the relation between these syndromes, the phenotypic spectrum in patients and female carriers, and the relation to underlying PRS-I activity is limited. Methods We investigated a family with a novel PRPS1 mutation (c.830A > C, p.Gln277Pro) by extensive phenotyping, MRI, and genetic and enzymatic tests. Results The male index subject presented with an overlap of CMTX5 and Arts syndrome features, whereas his sister presented with prelingual DFN2. Both showed mild parietal and cerebellar atrophy on MRI. Enzymatically, PRS-I activity was undetectable in the index subject, reduced in his less affected sister, and normal in his unaffected mother. Conclusions Our findings demonstrate that CMTX5, Arts syndrome and DFN2 are phenotypic clusters on an intrafamilial continuum, including overlapping phenotypes even within individuals. The respective phenotypic presentation seems to be determined by the exact PRPS1 mutation and the residual enzyme activity, the latter being largely influenced by the degree of skewed X-inactivation. Finally, our findings show that brain atrophy might be more common in PRPS1-disorders than previously thought. PMID:24528855

  3. Linking metamorphic textures to U-Pb monazite in-situ geochronology to determine the age and nature of aluminosilicate-forming reactions in the northern Monashee Mountains, British Columbia

    NASA Astrophysics Data System (ADS)

    Gervais, Félix; Hynes, Andrew

    2013-02-01

    The Monashee Mountains of the Canadian Cordillera are thought to expose a classic Barrovian-facies series of isograds. The timing of aluminosilicate growth in the region was determined for four pelitic schist samples by combining textural relationships with monazite compositional zoning and monazite U-Pb geochronology conducted directly on thin-sections by the laser ablation method. Three distinct phases of kyanite growth are recorded in the kyanite zone: at c. 153 Ma, between 122 and 94 Ma and between 76 and 58 Ma. For each phase, monazite and garnet grew synchronously with kyanite, probably by a reaction involving the breakdown of staurolite. In contrast, sillimanite growth by muscovite dehydration melting occurred at or before c. 104 Ma in the sillimanite zone, and retrograde sillimanite grew in schists previously metamorphosed at the kyanite grade during the first two phases by the influx of hot, acidic fluids during top-to-the-east shearing at ca. 71 Ma. These results indicate that rocks metamorphosed at different places and different times in the orogen were juxtaposed prior to being overprinted at the sillimanite grade in the Late Cretaceous-Early Paleocene during the influx of hot fluids in a structurally coherent body deforming by easterly directed shearing. This study also provides new insight into monazite petrogenesis and suggests that, at least in some circumstances, monazite formation is linked to the staurolite-out reaction that produces kyanite.

  4. The Impact of Skills Development on Competitiveness: Empirical Evidence from a Cross-Country Analysis

    ERIC Educational Resources Information Center

    Onsomu, Eldah N.; Ngware, Moses W.; Manda, Damiano K.

    2010-01-01

    In the past half-century, most countries have emphasized the development of human capital as an instrument for economic growth, sustainable development, and improved global competitiveness. However, limited evidence exists on the link between skills development and a country's competitiveness. This paper examines the contribution and association…

  5. Limited Evidence That Competitive Food and Beverage Practices Affect Adolescent Consumption Behaviors

    ERIC Educational Resources Information Center

    Vericker, Tracy C.

    2013-01-01

    Childhood obesity is emerging as a considerable public health problem with no clear antidote. The school food environment is a potential intervention point for policy makers, with competitive food and beverage regulation as a possible policy lever. This research examines the link between competitive food and beverage availability in school and…

  6. Affirming the Goal: Is College and Career Readiness an Internationally Competitive Standard? Executive Summary

    ERIC Educational Resources Information Center

    ACT, Inc., 2011

    2011-01-01

    ACT examined the international competitiveness of college and career ready standards in the policy research report, Affirming the Goal: Is College and Career Readiness an Internationally Competitive Standard? In this study, ACT performed a linking analysis to identify the PISA (Program for International Student Assessment) scores in reading and…

  7. Recent advances in designing substrate-competitive protein kinase inhibitors.

    PubMed

    Han, Ki-Cheol; Kim, So Yeon; Yang, Eun Gyeong

    2012-01-01

    Protein kinases play central roles in cellular signaling pathways and their abnormal phosphorylation activity is inseparably linked with various human diseases. Therefore, modulation of kinase activity using potent inhibitors is an attractive strategy for the treatment of human disease. While most protein kinase inhibitors in clinical development are mainly targeted to the highly conserved ATP-binding sites and thus likely promiscuously inhibit multiple kinases including kinases unrelated to diseases, protein substrate-competitive inhibitors are more selective and expected to be promising therapeutic agents. Most substrate-competitive inhibitors mimic peptides derived from substrate proteins, or from inhibitory domains within kinases or inhibitor proteins. In addition, bisubstrate inhibitors are generated by conjugating substrate-competitive peptide inhibitors to ATP-competitive inhibitors to improve affinity and selectivity. Although structural information on protein kinases provides invaluable guidance in designing substrate-competitive inhibitors, other strategies including bioinformatics, computational modeling, and high-throughput screening are often employed for developing specific substrate-competitive kinase inhibitors. This review focuses on recent advances in the design and discovery of substrate-competitive inhibitors of protein kinases.

  8. Competition can lead to unexpected patterns in tropical ant communities

    NASA Astrophysics Data System (ADS)

    Ellwood, M. D. Farnon; Blüthgen, Nico; Fayle, Tom M.; Foster, William A.; Menzel, Florian

    2016-08-01

    Ecological communities are structured by competitive, predatory, mutualistic and parasitic interactions combined with chance events. Separating deterministic from stochastic processes is possible, but finding statistical evidence for specific biological interactions is challenging. We attempt to solve this problem for ant communities nesting in epiphytic bird's nest ferns (Asplenium nidus) in Borneo's lowland rainforest. By recording the frequencies with which each and every single ant species occurred together, we were able to test statistically for patterns associated with interspecific competition. We found evidence for competition, but the resulting co-occurrence pattern was the opposite of what we expected. Rather than detecting species segregation-the classical hallmark of competition-we found species aggregation. Moreover, our approach of testing individual pairwise interactions mostly revealed spatially positive rather than negative associations. Significant negative interactions were only detected among large ants, and among species of the subfamily Ponerinae. Remarkably, the results from this study, and from a corroborating analysis of ant communities known to be structured by competition, suggest that competition within the ants leads to species aggregation rather than segregation. We believe this unexpected result is linked with the displacement of species following asymmetric competition. We conclude that analysing co-occurrence frequencies across complete species assemblages, separately for each species, and for each unique pairwise combination of species, represents a subtle yet powerful way of detecting structure and compartmentalisation in ecological communities.

  9. The effect of cross-link distributions in axially-ordered, cross-linked networks

    PubMed Central

    Bennett, C. Brad; Kruczek, James; Rabson, D. A.; Matthews, W. Garrett; Pandit, Sagar A.

    2013-01-01

    Cross-linking between the constituent chains of biopolymers has a marked effect on their materials properties. In certain of these materials, such as fibrillar collagen, increases in cross-linking lead to an increase in the melting temperature. Fibrillar collagen is an axially-ordered network of cross-linked polymer chains exhibiting a broadened denaturation transition, which has been explained in terms of the successive denaturation with temperature of multiple species. We model axially-ordered cross-linked materials as stiff chains with distinct arrangements of cross-link-forming sites. Simulations suggest that systems composed of chains with identical arrangements of cross-link-forming sites exhibit critical behavior. In contrast, systems composed of non-identical chains undergo a crossover. This model suggests that the arrangement of cross-link-forming sites may contribute to the broadening of the denaturation transition in fibrillar collagen. PMID:23751928

  10. [Competition and prices in the Mexican pharmaceutical market].

    PubMed

    Molina-Salazar, Raúl E; González-Marín, Eloy; Carbajal-de Nova, Carolina

    2008-01-01

    The forms of market competition define prices. The pharmaceutical market contains submarkets with different levels of competition; on the one hand are the innovating products with patents, and on the other, generic products with or without trade names. Innovating medicines generally have monopolistic prices, but when the patents expire prices drop because of competition from therapeutic alternatives. The trade name makes it easier to maintain monopolistic prices. In Mexico, medicine prices in the private market are high--according to aggregated estimates and prices for specific medicines--which reflect the limitations of pharmaceutical market competition and the power of the trade name. The public segment enjoys competitive prices using the WHO strategy for essential medicines on the basis of the Essential List.

  11. Comparing pre- and post-copulatory mate competition using social network analysis in wild crickets

    PubMed Central

    Fisher, David N.; Rodríguez-Muñoz, Rolando

    2016-01-01

    Sexual selection results from variation in success at multiple stages in the mating process, including competition before and after mating. The relationship between these forms of competition, such as whether they trade-off or reinforce one another, influences the role of sexual selection in evolution. However, the relationship between these 2 forms of competition is rarely quantified in the wild. We used video cameras to observe competition among male field crickets and their matings in the wild. We characterized pre- and post-copulatory competition as 2 networks of competing individuals. Social network analysis then allowed us to determine 1) the effectiveness of precopulatory competition for avoiding postcopulatory competition, 2) the potential for divergent mating strategies, and 3) whether increased postcopulatory competition reduces the apparent reproductive benefits of male promiscuity. We found 1) limited effectiveness of precopulatory competition for avoiding postcopulatory competition; 2) males do not specifically engage in only 1 type of competition; and 3) promiscuous individuals tend to mate with each other, which will tend to reduce variance in reproductive success in the population and highlights the trade-off inherent in mate guarding. Our results provide novel insights into the works of sexual competition in the wild. Furthermore, our study demonstrates the utility of using network analyses to study competitive interactions, even in species lacking obvious social structure. PMID:27174599

  12. Linked Gravitational Radiation

    NASA Astrophysics Data System (ADS)

    Thompson, Amy; Swearngin, Joseph; Wickes, Alexander; Willem Dalhuisen, Jan; Bouwmeester, Dirk

    2013-04-01

    The electromagnetic knot is a topologically nontrivial solution to the vacuum Maxwell equations with the property that any two field lines belonging to either the electric, magnetic, or Poynting vector fields are closed and linked exactly once [1]. The relationship between the vacuum Maxwell and linearized Einstein equations, as expressed in the form of the spin-N massless field equations, suggests that gravitational radiation possesses analogous topologically nontrivial field configurations. Using twistor methods we find the analogous spin-2 solutions of Petrov types N, D, and III. Aided by the concept of tendex and vortex lines as recently developed for the physical interpretation of solutions in general relativity [2], we investigate the physical properties of these knotted gravitational fields by characterizing the topology of their associated tendex and vortex lines.[4pt] [1] Ranada, A. F. and Trueba, J. L., Mod. Nonlinear Opt. III, 119, 197 (2002).[2] Nichols, D. A., et al., Phys. Rev. D, 84 (2011).

  13. An experimental and DFT study of a disulfide-linked Schiff base: synthesis, characterization and crystal structure of bis (3-methoxy-salicylidene-2-aminophenyl) disulfide in its anhydrous and monohydrate forms.

    PubMed

    Ferraresi-Curotto, Verónica; Echeverría, Gustavo A; Piro, Oscar E; Pis-Diez, Reinaldo; González-Baró, Ana C

    2014-01-24

    A detailed structural and spectroscopic study of the disulfide Schiff base obtained from condensation of 2-aminothiophenol and o-vanillin is reported. It includes the analyses of the anhydrous and monohydrate forms of the title compound. Structures of both solids were resolved by X-ray diffraction methods. A comparison between experimental and theoretical results is presented. The conformational space was searched and geometries were optimized both in gas phase and including solvent effects. Vibrational (IR and Raman) and electronic spectra were measured and assigned with the help of computational methods based on the Density Functional Theory. Calculated MEP-derived atomic charges were calculated to predict coordination sites for metal complexes formation. PMID:24055676

  14. An experimental and DFT study of a disulfide-linked Schiff base: Synthesis, characterization and crystal structure of bis (3-methoxy-salicylidene-2-aminophenyl) disulfide in its anhydrous and monohydrate forms

    NASA Astrophysics Data System (ADS)

    Ferraresi-Curotto, Verónica; Echeverría, Gustavo A.; Piro, Oscar E.; Pis-Diez, Reinaldo; González-Baró, Ana C.

    2014-01-01

    A detailed structural and spectroscopic study of the disulfide Schiff base obtained from condensation of 2-aminothiophenol and o-vanillin is reported. It includes the analyses of the anhydrous and monohydrate forms of the title compound. Structures of both solids were resolved by X-ray diffraction methods. A comparison between experimental and theoretical results is presented. The conformational space was searched and geometries were optimized both in gas phase and including solvent effects. Vibrational (IR and Raman) and electronic spectra were measured and assigned with the help of computational methods based on the Density Functional Theory. Calculated MEP-derived atomic charges were calculated to predict coordination sites for metal complexes formation.

  15. Cross-linked biopolymer bundles: Cross-link reversibility leads to cooperative binding/unbinding phenomena

    NASA Astrophysics Data System (ADS)

    Vink, Richard L. C.; Heussinger, Claus

    2012-01-01

    We consider a biopolymer bundle consisting of filaments that are cross-linked together. The cross-links are reversible: they can dynamically bind and unbind adjacent filament pairs as controlled by a binding enthalpy. The bundle is subjected to a bending deformation and the corresponding distribution of cross-links is measured. For a bundle consisting of two filaments, upon increasing the bending amplitude, a first-order transition is observed. The transition is from a state where the filaments are tightly coupled by many bound cross-links, to a state of nearly independent filaments with only a few bound cross-links. For a bundle consisting of more than two filaments, a series of first-order transitions is observed. The transitions are connected with the formation of an interface between regions of low and high cross-link densities. Combining umbrella sampling Monte Carlo simulations with analytical calculations, we present a detailed picture of how the competition between cross-link shearing and filament stretching drives the transitions. We also find that, when the cross-links become soft, collective behavior is not observed: the cross-links then unbind one after the other leading to a smooth decrease of the average cross-link density.

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

    PubMed Central

    Cole, Ella F.; Quinn, John L.

    2012-01-01

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

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

    PubMed

    Cole, Ella F; Quinn, John L

    2012-03-22

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

  18. More competitive silicon smelting

    SciTech Connect

    Valenti, M.

    1996-02-01

    Over the past several years, foreign manufacturers of ferrosilicon and silicon alloys have been making inroads in American markets such as computer chips. To make domestic smelting of these materials more competitive, the US Department of Energy (DOE) has funded the development of a direct-current plasma-arc-furnace smelting process by the South Carolina Research Authority (SCRA) in North Charleston. This new technology can reduce the energy consumption of the smelting process, saving million of dollars in energy costs per year. Typically, silicon and ferrosilicon alloys are produced in open-top, submerged-arc, alternating-current furnaces. A mixture of quartz ore and reducing agents are fed into the furnace, multiple electrodes are inserted into the material, and the mixture is charged to produce the desired metal. The process consumes high amounts of electrical power relative to the amount of metal recovered.

  19. Analyzing Optical Communications Links

    NASA Technical Reports Server (NTRS)

    Marshall, William K.; Burk, Brian D.

    1990-01-01

    Optical Communication Link Analysis Program, OPTI, analyzes optical and near-infrared communication links using pulse-position modulation (PPM) and direct detention. Link margins and design-control tables generated from input parameters supplied by user. Enables user to save sets of input parameters that define given link and read them back into program later. Alters automatically any of input parameters to achieve desired link margin. Written in FORTRAN 77.

  20. Mapping your competitive position.

    PubMed

    D'Aveni, Richard A

    2007-11-01

    A price-benefit positioning map helps you see, through your customers' eyes, how your product compares with all its competitors in a market. You can draw such a map quickly and objectively, without having to resort to costly, time-consuming consumer surveys or subjective estimates of the excellence of your product and the shortcomings of all the others. Creating a positioning map involves three steps: First, define your market to include everything your customers might consider to be your product's competitors or substitutes. Second, track the price your customers actually pay (wholesale or retail? bundled or unbundled?) and identify what your customers see as your offering's primary benefit. This is done through regression analysis, determining which of the product's attributes (as described objectively by rating services, government agencies, R&D departments, and the like) explains most of the variance in its price. Third, draw the map by plotting on a graph the position of every product in the market you've selected according to its price and its level of primary benefit, and draw a line that runs through the middle of the points. What you get is a picture of the competitive landscape of your market, where all the products above the line command a price premium owing to some secondary benefit customers value, and all those below the line are positioned to earn market share through lower prices and reduced secondary benefits. Using examples as varied as Harley-Davidson motorcycles, Motorola cell phones, and the New York restaurant market, Tuck professor D'Aveni demonstrates some of the many ways the maps can be used: to locate unoccupied or less-crowded spaces in highly competitive markets, for instance, or to identify opportunities created through changes in the relationship between the primary benefit and prices. The maps even allow companies to anticipate--and counter-- rivals' strategies. R eprint RO711G PMID:18159791

  1. Mapping your competitive position.

    PubMed

    D'Aveni, Richard A

    2007-11-01

    A price-benefit positioning map helps you see, through your customers' eyes, how your product compares with all its competitors in a market. You can draw such a map quickly and objectively, without having to resort to costly, time-consuming consumer surveys or subjective estimates of the excellence of your product and the shortcomings of all the others. Creating a positioning map involves three steps: First, define your market to include everything your customers might consider to be your product's competitors or substitutes. Second, track the price your customers actually pay (wholesale or retail? bundled or unbundled?) and identify what your customers see as your offering's primary benefit. This is done through regression analysis, determining which of the product's attributes (as described objectively by rating services, government agencies, R&D departments, and the like) explains most of the variance in its price. Third, draw the map by plotting on a graph the position of every product in the market you've selected according to its price and its level of primary benefit, and draw a line that runs through the middle of the points. What you get is a picture of the competitive landscape of your market, where all the products above the line command a price premium owing to some secondary benefit customers value, and all those below the line are positioned to earn market share through lower prices and reduced secondary benefits. Using examples as varied as Harley-Davidson motorcycles, Motorola cell phones, and the New York restaurant market, Tuck professor D'Aveni demonstrates some of the many ways the maps can be used: to locate unoccupied or less-crowded spaces in highly competitive markets, for instance, or to identify opportunities created through changes in the relationship between the primary benefit and prices. The maps even allow companies to anticipate--and counter-- rivals' strategies. R eprint RO711G

  2. Immunological impact of Taekwondo competitions.

    PubMed

    Lee, Y W; Shin, K W; Paik, I-Y; Jung, W M; Cho, S-Y; Choi, S T; Kim, H D; Kim, J Y

    2012-01-01

    Immunological changes in elite adolescent female athletes during Taekwondo competitions were investigated on-field. 6 female athletes (16.7 ± 0.8 year-old) volunteered and performed 5 bouts of demonstration Taekwondo competitions simulating real tournaments in intensity, duration, and break-time intervals on the same day. Blood samples were taken before, after the competitions and during the recovery, respectively. Immunological changes and oxidative stress in peripheral blood mononuclear cells were evaluated by flow-cytometry. During the competitions, exercise intensity was 92.2 ± 3.8% (86.1~95.7) of the maximal heart rate. Blood lactate increased immediately after the competitions (p=0.0165) and decreased to baseline during recovery. Intracellular reactive oxygen species (ROS) in the peripheral blood increased continuously during recovery (p<0.05, respectively). Natural killer cells increased immediately after the competitions (p=0.0006), and decreased during recovery. B and T cells increased immediately after the competitions and remained elevated throughout recovery (p<0.05, respectively). CD4/CD8 ratio after the competitions was decreased (p=0.0091) and returned to baseline during recovery. These results suggest that the immunological function of the elite female adolescent athletes could be attenuated after Taekwondo competitions. Further large-scaled Taekwondo studies on immunologic and apoptotic changes related to oxidative stress should be performed for improving and protecting the health of adolescent athletes.

  3. Spatial Aspects of Interspecific Competition

    NASA Technical Reports Server (NTRS)

    Durrett, Rick; Levin, Simon

    1998-01-01

    Using several variants of a stochastic spatial model introduced by Silvertown et al., we investigate the effect of spatial distribution of individuals on the outcome of competition. First, we prove rigorously that if one species has a competitive advantage over each of the others, then eventually it takes over all the sites in the system. Second, we examine tradeoffs between competition and dispersal distance in a two-species system. Third, we consider a cyclic competitive relationship between three types. In this case, a nonspatial treatment leads to densities that follow neutrally stable cycles or even unstable spiral solutions, while a spatial model yields a stationary distribution with an interesting spatial structure.

  4. Gender differences in competitive stress.

    PubMed

    Madden, C C; Kirkby, R J

    1995-06-01

    Stress experienced in competitive basketball was investigated in a sample of 84 men and 49 women recruited from players engaged in regular, organized, competitive grade basketball. Subjects were administered the Stressful Situations in Basketball Questionnaire which provides measures on 5 types of stress in competitive basketball. Analyses of gender differences showed that men reported more stress than female players on the "Team performance" scale. Research is required to evaluate whether this difference is due to a perception of women that they have less influence over the performance of the team or whether it is due to men having a higher stake in the results of competition.

  5. Severity of seabed spatial competition decreases towards the poles.

    PubMed

    Barnes, D K A; Neutel, A M

    2016-04-25

    For more than a century ecologists have considered that competitive interactions between species are more intense at low latitudes [1,2]. This is frequently invoked as either an explanation or a consequence of higher species richness in the tropics, also suggesting that competition shifts from intra- to inter-specific towards the tropics [1]. Another common assumption is that within a community, intraspecific competition needs to be relatively strong, compared to inter-specific competition, in order to enable stable coexistence of species [3]. However, many analyses have found no consistent large scale geographic patterns in the intensity of intra- or interspecific competition [4]. Here, we show a clear latitudinal trend in contest competition for space in nearshore marine environments, for bryozoans (sessile, colonial, suspension feeding animals). Bryozoans form species-rich assemblages with other encrusting fauna and flora (corraline algae), and are highly abundant across the globe [5]. We find that whilst the intensity of competition (percentage of bryozoan colonies involved in direct physical spatial interactions with bryozoan or other encrusters) differed little with latitude, its severity (percentage of bryozoan colonies involved in contests with a win/loss outcome, leading to death of the loser) was three times lower at the poles than in the tropics. The cause of this change in severity was a strong shift in taxonomic relatedness of competitors, from interactions between species of different families dominating at lower latitudes, to mainly intraspecific competition at the poles.

  6. [Competition in healthcare--a health systems' perspective].

    PubMed

    Busse, Reinhard

    2009-01-01

    That "more competition in healthcare primarily produces more needs-based equity, better quality, higher efficiency, reduced costs and less bureaucracy" is a familiar claim. But is it correct? Three types of competition can be identified within a triangle: (1) competition among third-party-payers for insured individuals/customers, (2) competition among providers for patients, and (3) competition among third-party payers for contracts with providers--and vice versa. German and international evidence for these three types of competition demonstrates that many expectations--e.g., that patients can be steered based on quality information--are wishful thinking. Instead of market and competition, regulation is needed (e.g., in the form of an effective risk-based allocation mechanism) to ensure high-quality care for those 5% of the population incurring 50% of the healthcare expenditures (i.e., the seriously ill patients), while at the same time competition based on selective contracts does not pay off for the majority of the population due to high transaction costs.

  7. Martial arts sports medicine: current issues and competition event coverage.

    PubMed

    Nishime, Robert S

    2007-06-01

    More sports medicine professionals are becoming actively involved in the care of the martial arts athlete. Although there are many different forms of martial arts practiced worldwide, certain styles have shown a potential for increased participation in competitive-type events. Further research is needed to better understand the prevalence and profiles of injuries sustained in martial arts full-contact competitive events. Breaking down the martial art techniques into basic concepts of striking, grappling, and submission maneuvers, including choking and joint locking, may facilitate better understanding and management of injuries. This article outlines this approach and reviews the commonly encountered injuries and problems during martial arts full-contact competitions.

  8. Student Advertising Competitions: Student Perspectives on the AAF Competition.

    ERIC Educational Resources Information Center

    Marra, James L.; Avery, James R.

    An exploratory study examined student perspectives and beliefs about involvement in the American Advertising Federation's (AAF) National Student Advertising Competition. Subjects, 34 students from 7 of the 15 winning regional teams in the 1991 AAF competition, completed a single-page, 2-part questionnaire. Multiple correlations were run on…

  9. Permission Forms

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2005-01-01

    The prevailing practice in public schools is to routinely require permission or release forms for field trips and other activities that pose potential for liability. The legal status of such forms varies, but they are generally considered to be neither rock-solid protection nor legally valueless in terms of immunity. The following case and the…

  10. Computational models of intergroup competition and warfare.

    SciTech Connect

    Letendre, Kenneth; Abbott, Robert G.

    2011-11-01

    This document reports on the research of Kenneth Letendre, the recipient of a Sandia Graduate Research Fellowship at the University of New Mexico. Warfare is an extreme form of intergroup competition in which individuals make extreme sacrifices for the benefit of their nation or other group to which they belong. Among animals, limited, non-lethal competition is the norm. It is not fully understood what factors lead to warfare. We studied the global variation in the frequency of civil conflict among countries of the world, and its positive association with variation in the intensity of infectious disease. We demonstrated that the burden of human infectious disease importantly predicts the frequency of civil conflict and tested a causal model for this association based on the parasite-stress theory of sociality. We also investigated the organization of social foraging by colonies of harvester ants in the genus Pogonomyrmex, using both field studies and computer models.

  11. Competition and cooperation in dynamic replication networks.

    PubMed

    Dadon, Zehavit; Wagner, Nathaniel; Alasibi, Samaa; Samiappan, Manickasundaram; Mukherjee, Rakesh; Ashkenasy, Gonen

    2015-01-01

    The simultaneous replication of six coiled-coil peptide mutants by reversible thiol-thioester exchange reactions is described. Experimental analysis of the time dependent evolution of networks formed by the peptides under different conditions reveals a complex web of molecular interactions and consequent mutant replication, governed by competition for resources and by autocatalytic and/or cross-catalytic template-assisted reactions. A kinetic model, first of its kind, is then introduced, allowing simulation of varied network behaviour as a consequence of changing competition and cooperation scenarios. We suggest that by clarifying the kinetic description of these relatively complex dynamic networks, both at early stages of the reaction far from equilibrium and at later stages approaching equilibrium, one lays the foundation for studying dynamic networks out-of-equilibrium in the near future.

  12. Increased competition does not lead to increased phylogenetic overdispersion in a native grassland.

    PubMed

    Bennett, Jonathan A; Lamb, Eric G; Hall, Jocelyn C; Cardinal-McTeague, Warren M; Cahill, James F

    2013-09-01

    That competition is stronger among closely related species and leads to phylogenetic overdispersion is a common assumption in community ecology. However, tests of this assumption are rare and field-based experiments lacking. We tested the relationship between competition, the degree of relatedness, and overdispersion among plants experimentally and using a field survey in a native grassland. Relatedness did not affect competition, nor was competition associated with phylogenetic overdispersion. Further, there was only weak evidence for increased overdispersion at spatial scales where plants are likely to compete. These results challenge traditional theory, but are consistent with recent theories regarding the mechanisms of plant competition and its potential effect on phylogenetic structure. We suggest that specific conditions related to the form of competition and trait conservatism must be met for competition to cause phylogenetic overdispersion. Consequently, overdispersion as a result of competition is likely to be rare in natural communities.

  13. The 2005 Australian Informatics Competition

    ERIC Educational Resources Information Center

    Clark, David

    2006-01-01

    This article describes the Australian Informatics Competition (AIC), a non-programming competition aimed at identifying students with potential in programming and algorithmic design. It is the first step in identifying students to represent Australia at the International Olympiad in Informatics. The main aim of the AIC is to increase awareness of…

  14. Fresno County Mock Trial Competition.

    ERIC Educational Resources Information Center

    Fresno City Unified School District, CA.

    THE FOLLOWING IS THE FULL TEXT OF THIS DOCUMENT: The Fresno County Office of Education and the Fresno Unified School District hosted the Mock Trial Competition. The state competition is sponsored by the Constitutional Rights Foundation, with cosponsorship from the California State Bar Association and the California Young Lawyer's Association. This…

  15. Neurocognitive Performance: Returning to Competition

    ERIC Educational Resources Information Center

    McDaniel, Larry W.; McIntire, Kyle

    2010-01-01

    Athletes who suffer from concussions under report their symptoms in order to expedite their return to competition. Athletic trainers and coaches must be aware of what is going on with athletes, even if it means requiring them to refrain from competition. Ninety percent of concussions are minor and can be difficult to diagnosis. There is a lack of…

  16. An Approach to Competitive Assessment.

    ERIC Educational Resources Information Center

    Green, Petrina M.

    1994-01-01

    Offers a detailed discussion of competitive assessment, an efficient and cost-effective method to evaluate competitive products. Describes its three phases: numerical scoring, building a best-of-breed model, and determining the gap between the best-of-breed model and another product. (SR)

  17. Competitive Electricity Prices: An Update

    EIA Publications

    1998-01-01

    Illustrates a third impact of the move to competitive generation pricing -- the narrowing of the range of prices across regions of the country. This feature article updates information in Electricity Prices in a Competitive Environment: Marginal Cost Pricing of Generation Services and Financial Status of Electric Utilities.

  18. Higher Education, Employability and Competitiveness

    ERIC Educational Resources Information Center

    Pavlin, Samo; Svetlicic, Marjan

    2012-01-01

    This paper studies the relationship between competitiveness and higher education systems in Europe. It explores whether more competitive countries have developed more labour-market-oriented systems of higher education (HE) that thereby give their graduates greater short term employability potential. Based on and a large-scale survey among 45.000…

  19. Competitive strategy a new era.

    PubMed

    Zuckerman, Alan M

    2007-11-01

    By adopting five basic practices, your organization will be ready to advance to the next level of competitive fitness: Develop a reliable financial baseline. Insist on development of a competitive intelligence database system. Employ rigorous business planning. Advocate for focus and discipline. Really commit to competing.

  20. Feature Discovery by Competitive Learning.

    ERIC Educational Resources Information Center

    Rumelhart, David E.; Zipser, David

    1985-01-01

    Reports results of studies with an unsupervised learning paradigm called competitive learning which is examined using computer simulation and formal analysis. When competitive learning is applied to parallel networks of neuron-like elements, many potentially useful learning tasks can be accomplished. (Author)

  1. DOE Collegiate Wind Competition (Presentation)

    SciTech Connect

    Jones, J.

    2014-02-01

    This presentation for the January Stakeholder Engagement and Outreach webinar outlines the expanded need for workers in the wind industry and provides an overview of the DOE Wind Competition (to be held in May 2014) and the guiding principles of the competition.

  2. Competitive Skills Project. Final Report.

    ERIC Educational Resources Information Center

    El Camino Coll., Torrance, CA.

    Almost 180 (22.5 percent) of BP Chemicals/HITCO, Inc. (BPCHI) employees have participated in the basic skills courses offered through the Competitive Skills Project (CSP) at El Camino College (Torrance, California). Workplace basics provide a solid foundation for Total Quality Management (TQM), enabling workers to be globally competitive. Two main…

  3. Interfacial Bioorthogonal Cross-Linking

    PubMed Central

    2015-01-01

    Described herein is interfacial bioorthogonal cross-linking, the use of bioorthogonal chemistry to create and pattern biomaterials through diffusion-controlled gelation at the liquid-gel interface. The basis is a rapid (k2 284000 M–1 s–1) reaction between strained trans-cyclooctene (TCO) and tetrazine (Tz) derivatives. Syringe delivery of Tz-functionalized hyaluronic acid (HA-Tz) to a bath of bis-TCO cross-linker instantly creates microspheres with a cross-linked shell through which bis-TCO diffuses freely to introduce further cross-linking at the interface. Tags can be introduced with 3D resolution without external triggers or templates. Water-filled hydrogel channels were prepared by simply reversing the order of addition. Prostate cancer cells encapsulated in the microspheres have 99% viability, proliferate readily, and form aggregated clusters. This process is projected to be useful in the fabrication of cell-instructive matrices for in vitro tissue models. PMID:25177528

  4. How competition affects evolutionary rescue

    PubMed Central

    Osmond, Matthew Miles; de Mazancourt, Claire

    2013-01-01

    Populations facing novel environments can persist by adapting. In nature, the ability to adapt and persist will depend on interactions between coexisting individuals. Here we use an adaptive dynamic model to assess how the potential for evolutionary rescue is affected by intra- and interspecific competition. Intraspecific competition (negative density-dependence) lowers abundance, which decreases the supply rate of beneficial mutations, hindering evolutionary rescue. On the other hand, interspecific competition can aid evolutionary rescue when it speeds adaptation by increasing the strength of selection. Our results clarify this point and give an additional requirement: competition must increase selection pressure enough to overcome the negative effect of reduced abundance. We therefore expect evolutionary rescue to be most likely in communities which facilitate rapid niche displacement. Our model, which aligns to previous quantitative and population genetic models in the absence of competition, provides a first analysis of when competitors should help or hinder evolutionary rescue. PMID:23209167

  5. Good form.

    PubMed

    Sorrel, Amy Lynn

    2015-03-01

    New standardized prior authorization forms for health care services and prescription drugs released by the Texas Department of Insurance promise to alleviate administrative busy work and its related costs.

  6. Modeling spatial competition for light in plant populations with the porous medium equation.

    PubMed

    Beyer, Robert; Etard, Octave; Cournède, Paul-Henry; Laurent-Gengoux, Pascal

    2015-02-01

    We consider a plant's local leaf area index as a spatially continuous variable, subject to particular reaction-diffusion dynamics of allocation, senescence and spatial propagation. The latter notably incorporates the plant's tendency to form new leaves in bright rather than shaded locations. Applying a generalized Beer-Lambert law allows to link existing foliage to production dynamics. The approach allows for inter-individual variability and competition for light while maintaining robustness-a key weakness of comparable existing models. The analysis of the single plant case leads to a significant simplification of the system's key equation when transforming it into the well studied porous medium equation. Confronting the theoretical model to experimental data of sugar beet populations, differing in configuration density, demonstrates its accuracy. PMID:24623311

  7. Modeling spatial competition for light in plant populations with the porous medium equation.

    PubMed

    Beyer, Robert; Etard, Octave; Cournède, Paul-Henry; Laurent-Gengoux, Pascal

    2015-02-01

    We consider a plant's local leaf area index as a spatially continuous variable, subject to particular reaction-diffusion dynamics of allocation, senescence and spatial propagation. The latter notably incorporates the plant's tendency to form new leaves in bright rather than shaded locations. Applying a generalized Beer-Lambert law allows to link existing foliage to production dynamics. The approach allows for inter-individual variability and competition for light while maintaining robustness-a key weakness of comparable existing models. The analysis of the single plant case leads to a significant simplification of the system's key equation when transforming it into the well studied porous medium equation. Confronting the theoretical model to experimental data of sugar beet populations, differing in configuration density, demonstrates its accuracy.

  8. Competition among leukemic cells.

    PubMed

    Aflalo, E; Weinstein, Y

    1990-01-01

    We investigated competition among leukemic cells induced by Moloney murine leukemia virus (MoLV) in order to understand the mechanisms involved in the generation of leukemia. We used six leukemic cells lines from Balb/C mice infected with MoLV. Each line had a unique genetic marker which enabled us to trace it in mixtures of cells either in vivo or in vitro. The markers were a unique rearrangement of T-cell receptors, the integration sites of the retrovirus and rearrangements in the Pim-1 oncogene. A mixture of two cell lines (1:1) injected into intact Balb/C mice usually produced a monoclonal tumor originating from one cell line. In most cases, the cell lines that were aggressive in vivo were also dominant in mixing experiments in vitro. In some lines, we could correlate the aggressiveness of the tumor to its superior growth rate and lower requirement for serum factors in vitro. In others, this correlation did not hold, and we assumed that host factors like the immune system contribute to the malignant potential of the leukemic cell.

  9. Mechanics of competition walking.

    PubMed

    Cavagna, G A; Franzetti, P

    1981-06-01

    1. The work done at each step to lift and accelerate the centre of mass of the body has been measured in competition walkers during locomotion from 2 to 20 km/hr. 2. Three distinct phases characterize the mechanics of walking. From 2 to 6 km/hr the vertical displacement during each step, Sv, increases to a maximum (3.5 vs. 6 cm in normal walking) due to an increase in the amplitude of the rotation over the supporting leg. 3. The transfer, R, between potential energy of vertical displacement and kinetic energy of forward motion during this rotation, reaches a maximum at 4-5 km/hr (R = 65%). From 6 to 10 km/hr R decreases more steeply than in normal walking, indicating a smaller utilization of the pendulum-like mechanism characteristic of walking. 4. Above 10 km/hr potential and kinetic energies vary during each step because both are simultaneously taken up and released by the muscles with almost no transfer between them (R = 2-10%). Above 13-14 km/hr an aerial phase (25-60 msec) takes place during the step. 5. Speeds considerably greater than in normal walking are attained thanks to a greater efficiency of doing positive work. This is made possible by a mechanism of locomotion allowing an important storage and recovery of mechanical energy by the muscles.

  10. Female competition in chimpanzees.

    PubMed

    Pusey, Anne E; Schroepfer-Walker, Kara

    2013-01-01

    Female chimpanzees exhibit exceptionally slow rates of reproduction and raise their offspring without direct paternal care. Therefore, their reproductive success depends critically on long-term access to high-quality food resources over a long lifespan. Chimpanzee communities contain multiple adult males, multiple adult females and their offspring. Because males are philopatric and jointly defend the community range while most females transfer to new communities before breeding, adult females are typically surrounded by unrelated competitors. Communities are fission-fusion societies in which individuals spend time alone or in fluid subgroups, whose size depends mostly on the abundance and distribution of food. To varying extents in different populations, females avoid direct competition by foraging alone or in small groups in distinct, but overlapping core areas within the community range to which they show high fidelity. Although rates of aggression are low, females compete for space and access to food. High rank correlates with high reproductive success, and high-ranking females win direct contests for food and gain preferential access to resource-rich sites. Females are aggressive to immigrant females and even kill the newborn infants of community members. The intensity of such aggression correlates with population density. These patterns are compared to those in other species, including humans.

  11. The Structure of Tip Links and Kinocilial Links in Avian Sensory Hair Bundles

    PubMed Central

    Tsuprun, Vladimir; Goodyear, Richard J.; Richardson, Guy P.

    2004-01-01

    Recent studies have indicated that the tip links and kinocilial links of sensory hair bundles in the inner ear have similar properties and share a common epitope, and that cadherin 23 may also be a component of each link type. Transmission electron microscopy was therefore used to study and compare the fine structure of the tip links and kinocilial links in avian sensory hair bundles. Tannic acid treatment revealed a thin strand, 150–200 nm long and 8–11 nm thick, present in both link types. Fourier analysis of link images showed that the strand of both link types is formed from two filaments coiled in a helix-like arrangement with an axial period of 20–25 nm, with each filament composed of globular structures that are ∼4 nm in diameter. Differences in the radius and period of the helix-like structure may underlie the observed variation in the length of tip and kinocilial links. The similar helix-like structure of the tip links and kinocilial links is in accord with the presence of a common cell-surface antigen (TLA antigen) and similarities in the physical and chemical properties of the two link types. The spacing of the globular structures comprising each filament of the two link types is similar to the 4.3 nm center-to-center spacing reported for the globular cadherin repeat, and is consistent with the suggestion that cadherin 23 is the tip link. PMID:15377520

  12. Isolation of cross-linked peptides by diagonal strong cation exchange chromatography for protein complex topology studies by peptide fragment fingerprinting from large sequence databases.

    PubMed

    Buncherd, Hansuk; Roseboom, Winfried; Ghavim, Behrad; Du, Weina; de Koning, Leo J; de Koster, Chris G; de Jong, Luitzen

    2014-06-27

    Knowledge of spatial proximity of amino acid residues obtained by chemical cross-linking and mass spectrometric analysis provides information about protein folding, protein-protein interactions and topology of macromolecular assemblies. We show that the use of bis(succinimidyl)-3-azidomethyl glutarate as a cross-linker provides a solution for two major analytical problems of cross-link mapping by peptide fragment fingerprinting (PFF) from complex sequence databases, i.e., low abundance of protease-generated target peptides and lack of knowledge of the masses of linked peptides. Tris(carboxyethyl)phosphine (TCEP) reduces the azido group in cross-linked peptides to an amine group in competition with cleavage of an amide bond formed in the cross-link reaction. TCEP-induced reaction products were separated by diagonal strong cation exchange (SCX) from unmodified peptides. The relation between the sum of the masses of the cleavage products and the mass of the parent cross-linked peptide enables determination of the masses of candidate linked peptides. By reversed phase LC-MS/MS analysis of secondary SCX fractions, we identified several intraprotein and interprotein cross-links in a HeLa cell nuclear extract, aided by software tools supporting PFF from the entire human sequence database. The data provide new information about interacting protein domains, among others from assemblies involved in splicing.

  13. 5 CFR 351.402 - Competitive area.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Competitive area. 351.402 Section 351.402... Competition § 351.402 Competitive area. (a) Each agency shall establish competitive areas in which employees compete for retention under this part. (b) A competitive area must be defined solely in terms of...

  14. 5 CFR 351.402 - Competitive area.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Competitive area. 351.402 Section 351.402... Competition § 351.402 Competitive area. (a) Each agency shall establish competitive areas in which employees compete for retention under this part. (b) A competitive area must be defined solely in terms of...

  15. 5 CFR 351.402 - Competitive area.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Competitive area. 351.402 Section 351.402... Competition § 351.402 Competitive area. (a) Each agency shall establish competitive areas in which employees compete for retention under this part. (b) A competitive area must be defined solely in terms of...

  16. 5 CFR 351.402 - Competitive area.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Competitive area. 351.402 Section 351.402... Competition § 351.402 Competitive area. (a) Each agency shall establish competitive areas in which employees compete for retention under this part. (b) A competitive area must be defined solely in terms of...

  17. 5 CFR 351.403 - Competitive level.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Competitive level. 351.403 Section 351... FORCE Scope of Competition § 351.403 Competitive level. (a)(1) Each agency shall establish competitive levels consisting of all positions in a competitive area which are in the same grade (or...

  18. 5 CFR 351.403 - Competitive level.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Competitive level. 351.403 Section 351... FORCE Scope of Competition § 351.403 Competitive level. (a)(1) Each agency shall establish competitive levels consisting of all positions in a competitive area which are in the same grade (or...

  19. Commercial Web Site Links.

    ERIC Educational Resources Information Center

    Thelwall, Mike

    2001-01-01

    Discusses business use of the Web and related search engine design issues as well as research on general and academic links before reporting on a survey of the links published by a collection of business Web sites. Results indicate around 66% of Web sites do carry external links, most of which are targeted at a specific purpose, but about 17%…

  20. Sperm competition and ejaculate economics.

    PubMed

    Parker, Geoff A; Pizzari, Tommaso

    2010-11-01

    Sperm competition was identified in 1970 as a pervasive selective force in post-copulatory sexual selection that occurs when the ejaculates of different males compete to fertilise a given set of ova. Since then, sperm competition has been much studied both empirically and theoretically. Because sperm competition often favours large ejaculates, an important challenge has been to understand the evolution of strategies through which males invest in sperm production and economise sperm allocation to maximise reproductive success under competitive conditions. Sperm competition mechanisms vary greatly, depending on many factors including the level of sperm competition, space constraints in the sperm competition arena, male mating roles, and female influences on sperm utilisation. Consequently, theoretical models of ejaculate economics are complex and varied, often with apparently conflicting predictions. The goal of this review is to synthesise the theoretical basis of ejaculate economics under sperm competition, aiming to provide empiricists with categorised model assumptions and predictions. We show that apparent contradictions between older and newer models can often be reconciled and there is considerable consensus in the predictions generated by different models. We also discuss qualitative empirical support for some of these predictions, and detail quantitative matches between predictions and observations that exist in the yellow dung fly. We argue that ejaculate economic theory represents a powerful heuristic to explain the diversity in ejaculate traits at multiple levels: across species, across males and within individual males. Future progress requires greater understanding of sperm competition mechanisms, quantification of trade-offs between ejaculate allocation and numbers of matings gained, further knowledge of mechanisms of female sperm selection and their associated costs, further investigation of non-sperm ejaculate effects, and theoretical integration of

  1. Testosterone, cortisol, and human competition.

    PubMed

    Casto, Kathleen V; Edwards, David A

    2016-06-01

    Testosterone and cortisol figure prominently in the research literature having to do with human competition. In this review, we track the history of this literature, concentrating particularly on major theoretical and empirical contributions, and provide commentary on what we see as important unresolved issues. In men and women, athletic competition is typically associated with an increase in testosterone (T) and cortisol (C). Hormone changes in response to non-athletic competition are less predictable. Person (e.g., power motivation, mood, aggressiveness, social anxiety, sex, and baseline levels of T and C) and context (e.g., whether a competition is won or lost, the closeness of the competition, whether the outcome is perceived as being influenced by ability vs. chance, provocations) factors can influence hormone responses to competition. From early on, studies pointed to a positive relationship between T and dominance motivation/status striving. Recent research, however, suggests that this relationship only holds for individuals with low levels of C - this is the core idea of the dual-hormone hypothesis, and it is certain that the broadest applications of the hypothesis have not yet been realized. Individuals differ with respect to the extent to which they embrace competition, but the hormonal correlates of competitiveness remain largely unexplored. Although rapid increases in both T and C associated with competition are likely adaptive, we still know very little about the psychological benefits of these hormonal changes. Administration studies have and will continue to contribute to this inquiry. We close with a discussion of what, we think, are important methodological and mechanistic issues for future research.

  2. Testosterone, cortisol, and human competition.

    PubMed

    Casto, Kathleen V; Edwards, David A

    2016-06-01

    Testosterone and cortisol figure prominently in the research literature having to do with human competition. In this review, we track the history of this literature, concentrating particularly on major theoretical and empirical contributions, and provide commentary on what we see as important unresolved issues. In men and women, athletic competition is typically associated with an increase in testosterone (T) and cortisol (C). Hormone changes in response to non-athletic competition are less predictable. Person (e.g., power motivation, mood, aggressiveness, social anxiety, sex, and baseline levels of T and C) and context (e.g., whether a competition is won or lost, the closeness of the competition, whether the outcome is perceived as being influenced by ability vs. chance, provocations) factors can influence hormone responses to competition. From early on, studies pointed to a positive relationship between T and dominance motivation/status striving. Recent research, however, suggests that this relationship only holds for individuals with low levels of C - this is the core idea of the dual-hormone hypothesis, and it is certain that the broadest applications of the hypothesis have not yet been realized. Individuals differ with respect to the extent to which they embrace competition, but the hormonal correlates of competitiveness remain largely unexplored. Although rapid increases in both T and C associated with competition are likely adaptive, we still know very little about the psychological benefits of these hormonal changes. Administration studies have and will continue to contribute to this inquiry. We close with a discussion of what, we think, are important methodological and mechanistic issues for future research. PMID:27103058

  3. 76 FR 69738 - Revised 2011 Annual Telecommunications Reporting Worksheet (FCC Form 499-A) and Accompanying...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ... COMMISSION Revised 2011 Annual Telecommunications Reporting Worksheet (FCC Form 499-A) and Accompanying... Competition Bureau released the revised Telecommunications Reporting Worksheet (FCC Form 499-A) and... Budget approved revisions to the Telecommunications Reporting Worksheet, FCC Form 499-A (the Form)...

  4. FIRST 2002, 2003, 2004 Robotics Competition(s)

    NASA Technical Reports Server (NTRS)

    Purman, Richard

    2004-01-01

    The New Horizons Regional Education Center (NHREC) in Hampton, VA sought and received NASA funding to support its participation in the 2002, 2003, and 2004 FIRST Robotics Competitions. FIRST, Inc. (For Inspiration and Recognition of Science and Technology) is an organization which encourages the application of creative science, math, and computer science principles to solve real-world engineering problems. The FIRST competition is an international engineering contest featuring high school, government, and business partnerships.

  5. Distributional preferences and competitive behavior.

    PubMed

    Balafoutas, Loukas; Kerschbamer, Rudolf; Sutter, Matthias

    2012-06-01

    We study experimentally the relationship between distributional preferences and competitive behavior. We find that spiteful subjects react strongest to competitive pressure and win in a tournament significantly more often than efficiency-minded and inequality averse subjects. However, when given the choice between a tournament and a piece rate scheme, efficiency-minded subjects choose the tournament most often, while spiteful and inequality averse subjects avoid it. When controlling for distributional preferences, risk attitudes and past performance, the gender gap in the willingness to compete is no longer significant, indicating that gender-related variables explain why twice as many men as women self-select into competition.

  6. Gender and competitive preferences: The role of competition size.

    PubMed

    Hanek, Kathrin J; Garcia, Stephen M; Tor, Avishalom

    2016-08-01

    In a series of 8 studies, we examine whether gender differences in competition entry preferences are moderated by the size of the competition. Drawing on theories of gender roles and stereotypes, we show that women, relative to men, prefer to enter smaller compared with larger competitions. Studies 1a and 1b demonstrate this effect in observational data on preferences for working in differently sized firms and applying to differently sized colleges. Studies 2a and 2b replicate the effect with real behavioral decisions in different domains. We also find empirical evidence that prescriptive gender norms and stereotypes underlie this effect. In Study 3, we find experimental evidence that women and men differ in their preferences for differently sized groups under competition, but not in noncompetitive settings. Three additional experimental studies (Studies 4, 5a, and 5b) show that perceptions of comfort in small versus larger competitions underlie women's preferences. These findings suggest that women's preferences for smaller competitions may be driven by an adherence to prescriptive gender norms. We discuss the implications of the current findings for gender inequalities in organizations. (PsycINFO Database Record PMID:27176148

  7. Competitive advantages of Caedibacter-infected Paramecia.

    PubMed

    Kusch, Jürgen; Czubatinski, Lars; Wegmann, Silke; Hubner, Markus; Alter, Margret; Albrecht, Petra

    2002-03-01

    Intracellular bacteria of the genus Caedibacter limit the reproduction of their host, the freshwater ciliate Paramecium. Reproduction rates of infected strains of paramecia were significantly lower than those of genetically identical strains that had lost their parasites after treatment with an antibiotic. Interference competition occurs when infected paramecia release a toxic form of the parasitic bacterium that kills uninfected paramecia. In mixed cultures of infected and uninfected strains of either P tetraurelia or of P novaurelia, the infected strains outcompeted the uninfected strains. Infection of new host paramecia seems to be rare. Infection of new hosts was not observed in either mixtures of infected with uninfected strains, or after incubation of paramecia with isolated parasites. The competitive advantages of the host paramecia, in combination with their vegetative reproduction, makes infection of new hosts by the bacterial parasites unnecessary, and could be responsible for the continued existence of "killer paramecia" in nature. Caedibacter parasites are not a defensive adaptation. Feeding rates and reproduction of the predators Didinium nasutum (Ciliophora) and Amoeba proteus (Amoebozoa, Gymnamoebia) were not influenced by whether or not their paramecia prey were infected. Infection of the predators frequently occurred when they preyed on infected paramecia. Caedibacter-infected predators may influence competition between Paramecium strains by release of toxic parasites into the environment that are harmful to uninfected strains.

  8. Competitive advantages of Caedibacter-infected Paramecia.

    PubMed

    Kusch, Jürgen; Czubatinski, Lars; Wegmann, Silke; Hubner, Markus; Alter, Margret; Albrecht, Petra

    2002-03-01

    Intracellular bacteria of the genus Caedibacter limit the reproduction of their host, the freshwater ciliate Paramecium. Reproduction rates of infected strains of paramecia were significantly lower than those of genetically identical strains that had lost their parasites after treatment with an antibiotic. Interference competition occurs when infected paramecia release a toxic form of the parasitic bacterium that kills uninfected paramecia. In mixed cultures of infected and uninfected strains of either P tetraurelia or of P novaurelia, the infected strains outcompeted the uninfected strains. Infection of new host paramecia seems to be rare. Infection of new hosts was not observed in either mixtures of infected with uninfected strains, or after incubation of paramecia with isolated parasites. The competitive advantages of the host paramecia, in combination with their vegetative reproduction, makes infection of new hosts by the bacterial parasites unnecessary, and could be responsible for the continued existence of "killer paramecia" in nature. Caedibacter parasites are not a defensive adaptation. Feeding rates and reproduction of the predators Didinium nasutum (Ciliophora) and Amoeba proteus (Amoebozoa, Gymnamoebia) were not influenced by whether or not their paramecia prey were infected. Infection of the predators frequently occurred when they preyed on infected paramecia. Caedibacter-infected predators may influence competition between Paramecium strains by release of toxic parasites into the environment that are harmful to uninfected strains. PMID:12022275

  9. Lunabotics Mining Competition: Inspiration through Accomplishment

    NASA Technical Reports Server (NTRS)

    Mueller, Robert P.

    2012-01-01

    Space Mining for resources such as water ice, and regolith, which contain many elements in the form of metals, minerals, volatiles and other compounds, is a necessary step in Space Resource Utilization. One of the primary goals is to extract propellants from the regolith such as oxygen and hydrogen which could then be used for in-space transportation. In addition, the space mining system can be used for various construction tasks that can benefit human and robotic exploration as well as scientific investigations based on the exposed topography. The National Aeronautics & Space Administration (NASA) Lunabotics Mining Competition is a university-level competition designed to engage and retain students in science, technology, engineering and mathematics (STEM). NASA will directly benefit from the competition by encouraging the development of innovative lunar excavation concepts from universities which may result in clever ideas and solutions which could be applied to an actual lunar excavation device or payload. The challenge is for students to design and build a remote controlled or autonomous excavator, called a lunabot, that can collect and deposit a minimum of 10 kilograms of lunar simulant within 15 minutes. The complexities of the challenge include the abrasive characteristics of the lunar simulant, the weight and size limitations of the lunabot, and the ability to control the lunabot from a remote control center or operate autonomously. This paper will present an update of the results and lessons learned during the first and second annual Lunabotics Mining Competitions held in May 2010 and May 2011. It will also preview the 2012 competition with a review of the revised rules. In 2010,22 United States (US) universities competed, and in May 2011 the competition was opened to international participation. In 2011, 36 teams actually competed from 26 USA states and 4 foreign countries (India, Bangladesh, Colombia and Canada). This combined total directly inspired an

  10. Competition promotes the evolution of host generalists in obligate parasites.

    PubMed

    Johnson, Kevin P; Malenke, Jael R; Clayton, Dale H

    2009-11-22

    Ecological theory traditionally predicts that interspecific competition selects for an increase in ecological specialization. Specialization, in turn, is often thought to be an evolutionary 'dead end,' with specialist lineages unlikely to evolve into generalist lineages. In host-parasite systems, this specialization can take the form of host specificity, with more specialized parasites using fewer hosts. We tested the hypothesis that specialists are evolutionarily more derived, and whether competition favours specialization, using the ectoparasitic feather lice of doves. Phylogenetic analyses revealed that complete host specificity is actually the ancestral condition, with generalists repeatedly evolving from specialist ancestors. These multiple origins of generalists are correlated with the presence of potentially competing species of the same genus. A competition experiment with captive doves and lice confirmed that congeneric species of lice do, in fact, have the potential to compete in ecological time. Taken together, these results suggest that interspecific competition can favour the evolution of host generalists, not specialists, over macroevolutionary time.

  11. Social competition and selection in males and females

    PubMed Central

    Clutton-Brock, T. H.; Huchard, E.

    2013-01-01

    During the latter half of the last century, evidence of reproductive competition between males and male selection by females led to the development of a stereotypical view of sex differences that characterized males as competitive and aggressive, and females as passive and choosy, which is currently being revised. Here, we compare social competition and its consequences for selection in males and females and argue that similar selection processes operate in both sexes and that contrasts between the sexes are quantitative rather than qualitative. We suggest that classifications of selection based on distinction between the form of competition or the components of fitness that are involved introduce unnecessary complexities and that the most useful approach in understanding the evolution and distribution of differences and similarities between the sexes is to compare the operation of selection in males and females in different reproductive systems. PMID:24167304

  12. Patent Pools: Intellectual Property Rights and Competition

    PubMed Central

    Rodriguez, Victor

    2010-01-01

    Patent pools do not correct all problems associated with patent thickets. In this respect, patent pools might not stop the outsider problem from striking pools. Moreover, patent pools can be expensive to negotiate, can exclude patent holders with smaller numbers of patents or enable a group of major players to form a cartel that excludes new competitors. For all the above reasons, patent pools are subject to regulatory clearance because they could result in a monopoly. The aim of this article is to present the relationship between patents and competition in a broad context. PMID:20200607

  13. Competitive Strategy in Continuing Education.

    ERIC Educational Resources Information Center

    Baden, Clifford

    1987-01-01

    Reviews strategic variables available to those planning continuing education marketing programs. Discusses generic competitive strategies: (1) overall cost leadership, (2) differentiation, and (3) specialization. Mentions several potential problems. (CH)

  14. Sperm competition and the evolution of spermatogenesis.

    PubMed

    Ramm, Steven A; Schärer, Lukas; Ehmcke, Jens; Wistuba, Joachim

    2014-12-01

    Spermatogenesis is a long and complex process that, despite the shared overall goal of producing the male gamete, displays striking amounts of interspecific diversity. In this review, we argue that sperm competition has been an important selection pressure acting on multiple aspects of spermatogenesis, causing variation in the number and morphology of sperm produced, and in the molecular and cellular processes by which this happens. We begin by reviewing the basic biology of spermatogenesis in some of the main animal model systems to illustrate this diversity, and then ask to what extent this variation arises from the evolutionary forces acting on spermatogenesis, most notably sperm competition. We explore five specific aspects of spermatogenesis from an evolutionary perspective, namely: (i) interspecific diversity in the number and morphology of sperm produced; (ii) the testicular organizations and stem cell systems used to produce them; (iii) the large number and high evolutionary rate of genes underpinning spermatogenesis; (iv) the repression of transcription during spermiogenesis and its link to the potential for haploid selection; and (v) the phenomenon of selection acting at the level of the germline. Overall we conclude that adopting an evolutionary perspective can shed light on many otherwise opaque features of spermatogenesis, and help to explain the diversity of ways in which males of different species perform this fundamentally important process. PMID:25323971

  15. Surviving competitive athletics with hypertrophic cardiomyopathy.

    PubMed

    Maron, B J; Klues, H G

    1994-06-01

    Hypertrophic cardiomyopathy (HC) is probably the most common cause of sudden cardiac death in youthful athletes, and this diagnosis has represented a contraindication to continued participation in competitive sports. Less well appreciated is the fact that within the clinical spectrum of HC are patients who, despite having this disease, have been able to undertake particularly intensive and often extraordinary levels of training for sports competition over many years without dying suddenly. Fourteen such patients (13 men and 1 woman, aged 30 to 66 years [mean 43]) form the present study group. HC was initially identified at 24 to 57 years of age (mean 34), usually under fortuitous circumstances. Patients most often competed in distance running (including the marathon, 7), but also in swimming, triathalon, basketball, and football. The duration of training ranged from 6 to 22 years (mean 15) and 5 continue to train and compete actively. The magnitude of training, competition, and achievement was considerable in most patients; 12 of the 14 performed either at the national, collegiate or professional level in their sport, completed numerous marathon and triathalon events, or sustained particularly rigorous training regimens of > or = 50 miles/week. Echocardiographic studies demonstrated a left ventricular wall thickness of 18 to 28 mm (mean 20) in most patients (12 of 14) having a relatively localized pattern of ventricular septal hypertrophy. It is possible for some patients with HC to tolerate particularly intense athletic training and competition for many years, and even maintain high levels of achievement without incurring symptoms and disease progression or dying suddenly.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Protein cross-linking by chlorinated polyamines and transglutamylation stabilizes neutrophil extracellular traps.

    PubMed

    Csomós, Krisztián; Kristóf, Endre; Jakob, Bernadett; Csomós, István; Kovács, György; Rotem, Omri; Hodrea, Judit; Bagoly, Zsuzsa; Muszbek, Laszlo; Balajthy, Zoltán; Csősz, Éva; Fésüs, László

    2016-01-01

    Neutrophil extracellular trap (NET) ejected from activated dying neutrophils is a highly ordered structure of DNA and selected proteins capable to eliminate pathogenic microorganisms. Biochemical determinants of the non-randomly formed stable NETs have not been revealed so far. Studying the formation of human NETs we have observed that polyamines were incorporated into the NET. Inhibition of myeloperoxidase, which is essential for NET formation and can generate reactive chlorinated polyamines through hypochlorous acid, decreased polyamine incorporation. Addition of exogenous primary amines that similarly to polyamines inhibit reactions catalyzed by the protein cross-linker transglutaminases (TGases) has similar effect. Proteomic analysis of the highly reproducible pattern of NET components revealed cross-linking of NET proteins through chlorinated polyamines and ɛ(γ-glutamyl)lysine as well as bis-γ-glutamyl polyamine bonds catalyzed by the TGases detected in neutrophils. Competitive inhibition of protein cross-linking by monoamines disturbed the cross-linking pattern of NET proteins, which resulted in the loss of the ordered structure of the NET and significantly reduced capacity to trap bacteria. Our findings provide explanation of how NETs are formed in a reproducible and ordered manner to efficiently neutralize microorganisms at the first defense line of the innate immune system. PMID:27512953

  17. An amusement park physics competition

    NASA Astrophysics Data System (ADS)

    Moll, Rachel F.

    2010-07-01

    Amusement park physics is a popular way to reinforce physics concepts and to motivate physics learners. This article describes a novel physics competition where students use simple tools to take amusement park ride measurements and use the data to answer challenging exam questions. Research into the impact of participating in the competition reveals positive effects such as the acquisition of experimentation skills and improved attitudes towards physics.

  18. Chemical defense lowers plant competitiveness.

    PubMed

    Ballhorn, Daniel J; Godschalx, Adrienne L; Smart, Savannah M; Kautz, Stefanie; Schädler, Martin

    2014-11-01

    Both plant competition and plant defense affect biodiversity and food web dynamics and are central themes in ecology research. The evolutionary pressures determining plant allocation toward defense or competition are not well understood. According to the growth-differentiation balance hypothesis (GDB), the relative importance of herbivory and competition have led to the evolution of plant allocation patterns, with herbivore pressure leading to increased differentiated tissues (defensive traits), and competition pressure leading to resource investment towards cellular division and elongation (growth-related traits). Here, we tested the GDB hypothesis by assessing the competitive response of lima bean (Phaseolus lunatus) plants with quantitatively different levels of cyanogenesis-a constitutive direct, nitrogen-based defense against herbivores. We used high (HC) and low cyanogenic (LC) genotypes in different competition treatments (intra-genotypic, inter-genotypic, interspecific), and in the presence or absence of insect herbivores (Mexican bean beetle, Epilachna varivestis) to quantify vegetative and generative plant parameters (above and belowground biomass as well as seed production). Highly defended HC-plants had significantly lower aboveground biomass and seed production than LC-plants when grown in the absence of herbivores implying significant intrinsic costs of plant cyanogenesis. However, the reduced performance of HC- compared to LC-plants was mitigated in the presence of herbivores. The two plant genotypes exhibited fundamentally different responses to various stresses (competition, herbivory). Our study supports the GDB hypothesis by demonstrating that competition and herbivory affect different plant genotypes differentially and contributes to understanding the causes of variation in defense within a single plant species.

  19. Interference competition and parasite virulence.

    PubMed Central

    Massey, Ruth C.; Buckling, Angus; ffrench-Constant, Richard

    2004-01-01

    Within-host competition between parasites, a consequence of infection by multiple strains, is predicted to favour rapid host exploitation and greater damage to hosts (virulence). However, the inclusion of biological variables can drastically change this relationship. For example, if competing parasite strains produce toxins that kill each other (interference competition), their growth rates and virulence may be reduced relative to single-strain infections. Bacteriocins are antimicrobial toxins produced by bacteria that target closely related strains and species, and to which the producing strain is immune. We investigated competition between bacteriocin-producing, insect-killing bacteria (Photorhabdus and Xenorhabdus) and how this competition affected virulence in caterpillars. Where one strain could kill the other, and not vice versa, the non-killing strain was competitively excluded, and insect mortality was the same as that of the killing strain alone. However, when caterpillars were multiply infected by strains that could kill each other, we did not observe competitive exclusion and their virulence was less than single-strain infections. The ubiquity and diversity of bacteriocins among pathogenic bacteria suggest mixed infections will be, on average, less virulent than single infections. PMID:15255095

  20. Pseudo-Equivalent Groups and Linking

    ERIC Educational Resources Information Center

    Haberman, Shelby J.

    2015-01-01

    Adjustment by minimum discriminant information provides an approach to linking test forms in the case of a nonequivalent groups design with no satisfactory common items. This approach employs background information on individual examinees in each administration so that weighted samples of examinees form pseudo-equivalent groups in the sense that…

  1. The formation of stars by gravitational collapse rather than competitive accretion.

    PubMed

    Krumholz, Mark R; McKee, Christopher F; Klein, Richard I

    2005-11-17

    There are two dominant models of how stars form. Under gravitational collapse, star-forming molecular clumps, of typically hundreds to thousands of solar masses (M(o)), fragment into gaseous cores that subsequently collapse to make individual stars or small multiple systems. In contrast, competitive accretion theory suggests that at birth all stars are much smaller than the typical stellar mass (approximately 0.5M(o)), and that final stellar masses are determined by the subsequent accretion of unbound gas from the clump. Competitive accretion models interpret brown dwarfs and free-floating planets as protostars ejected from star-forming clumps before they have accreted much mass; key predictions of this model are that such objects should lack disks, have high velocity dispersions, form more frequently in denser clumps, and that the mean stellar mass should vary within the Galaxy. Here we derive the rate of competitive accretion as a function of the star-forming environment, based partly on simulation, and determine in what types of environments competitive accretion can occur. We show that no observed star-forming region can undergo significant competitive accretion, and that the simulations that show competitive accretion do so because the assumed properties differ from those determined by observation. Our result shows that stars form by gravitational collapse, and explains why observations have failed to confirm predictions of the competitive accretion model.

  2. Changing competition in health care marketing: a method for analysis and strategic planning.

    PubMed

    Ellis, B; Brockman, B K

    1993-01-01

    As the cost and importance of healthcare continue to increase, competition in the medical industry is taking new forms and becoming more intense. The driving trends behind this competition are analyzed in the framework of Porter's Five Forces of Competition Model. The authors then discuss how the widely accepted strategies of cost, differentiation, focus, and domestication can be utilized to counter the implications of these trends and how to capitalize on opportunities in medical practice in the 1990's.

  3. Changing competition in health care marketing: a method for analysis and strategic planning.

    PubMed

    Ellis, B; Brockman, B K

    1993-01-01

    As the cost and importance of healthcare continue to increase, competition in the medical industry is taking new forms and becoming more intense. The driving trends behind this competition are analyzed in the framework of Porter's Five Forces of Competition Model. The authors then discuss how the widely accepted strategies of cost, differentiation, focus, and domestication can be utilized to counter the implications of these trends and how to capitalize on opportunities in medical practice in the 1990's. PMID:10127925

  4. Competitive helping in online giving.

    PubMed

    Raihani, Nichola J; Smith, Sarah

    2015-05-01

    Unconditional generosity in humans is a puzzle. One possibility is that individuals benefit from being seen as generous if there is competition for access to partners and if generosity is a costly-and therefore reliable-signal of partner quality [1-3]. The "competitive helping" hypothesis predicts that people will compete to be the most generous, particularly in the presence of attractive potential partners [1]. However, this key prediction has not been directly tested. Using data from online fundraising pages, we demonstrate competitive helping in the real world. Donations to fundraising pages are public and made sequentially. Donors can therefore respond to the behavior of previous donors, creating a potential generosity tournament. Our test of the competitive helping hypothesis focuses on the response to large, visible donations. We show that male donors show significantly stronger responses (by donating more) when they are donating to an attractive female fundraiser and responding to a large donation made by another male donor. The responses for this condition are around four times greater than when males give to less-attractive female (or male) fundraisers or when they respond to a large donation made by a female donor. Unlike males, females do not compete in donations when giving to attractive male fundraisers. These data suggest that males use competitive helping displays in the presence of attractive females and suggest a role for sexual selection in explaining unconditional generosity.

  5. The Scientific Competitiveness of Nations

    PubMed Central

    Cimini, Giulio; Gabrielli, Andrea; Sylos Labini, Francesco

    2014-01-01

    We use citation data of scientific articles produced by individual nations in different scientific domains to determine the structure and efficiency of national research systems. We characterize the scientific fitness of each nation—that is, the competitiveness of its research system—and the complexity of each scientific domain by means of a non-linear iterative algorithm able to assess quantitatively the advantage of scientific diversification. We find that technological leading nations, beyond having the largest production of scientific papers and the largest number of citations, do not specialize in a few scientific domains. Rather, they diversify as much as possible their research system. On the other side, less developed nations are competitive only in scientific domains where also many other nations are present. Diversification thus represents the key element that correlates with scientific and technological competitiveness. A remarkable implication of this structure of the scientific competition is that the scientific domains playing the role of “markers” of national scientific competitiveness are those not necessarily of high technological requirements, but rather addressing the most “sophisticated” needs of the society. PMID:25493626

  6. Can polymersomes form colloidosomes?

    PubMed

    Thompson, Kate L; Chambon, Pierre; Verber, Robert; Armes, Steven P

    2012-08-01

    Hydroxy-functionalized polymersomes (or block copolymer vesicles) were prepared via a facile one-pot RAFT aqueous dispersion polymerization protocol and evaluated as Pickering emulsifiers for the stabilization of emulsions of n-dodecane emulsion droplets in water. Linear polymersomes produced polydisperse oil droplets with diameters of ~50 μm regardless of the polymersome concentration in the aqueous phase. Introducing an oil-soluble polymeric diisocyanate cross-linker into the oil phase prior to homogenization led to block copolymer microcapsules, as expected. However, TEM inspection of these microcapsules after an alcohol challenge revealed no evidence for polymersomes, suggesting these delicate nanostructures do not survive the high-shear emulsification process. Thus the emulsion droplets are stabilized by individual diblock copolymer chains, rather than polymersomes. Cross-linked polymersomes (prepared by the addition of ethylene glycol dimethacrylate as a third comonomer) also formed stable n-dodecane-in-water Pickering emulsions, as judged by optical and fluorescence microscopy. However, in this case the droplet diameter varied from 50 to 250 μm depending on the aqueous polymersome concentration. Moreover, diisocyanate cross-linking at the oil/water interface led to the formation of well-defined colloidosomes, as judged by TEM studies. Thus polymersomes can indeed stabilize colloidosomes, provided that they are sufficiently cross-linked to survive emulsification.

  7. Cooperation and the scale of competition in humans.

    PubMed

    West, Stuart A; Gardner, Andy; Shuker, David M; Reynolds, Tracy; Burton-Chellow, Max; Sykes, Edward M; Guinnee, Meghan A; Griffin, Ashleigh S

    2006-06-01

    Explaining cooperation is one of the greatest challenges for evolutionary biology. It is particularly a problem in species such as humans, where there is cooperation between nonrelatives. Numerous possible solutions have been suggested for the problem of cooperation between nonrelatives, including punishment, policing, and various forms of reciprocity. Here, we suggest that local competition for resources can pose a problem for these hypotheses, analogous to how it can select against cooperation between relatives. We extend the prisoner's dilemma (PD) game to show that local competition between interacting individuals can reduce selection for cooperation between nonrelatives. This is because, with local competition, fitness is relative to social partners, and cooperation benefits social partners. We then test whether nonrelated humans adjust their level of cooperation facultatively in response to the scale of competition when playing the PD for cash prizes. As predicted, we found that individuals were less likely to cooperate when competition was relatively local. Cooperation between humans will therefore be most likely when repeated interactions take place on a local scale between small numbers of people, and competition for resources takes place on a more global scale among large numbers of people.

  8. Project X: competitive intelligence data mining and analysis

    NASA Astrophysics Data System (ADS)

    Gilmore, John F.; Pagels, Michael A.; Palk, Justin

    2001-03-01

    Competitive Intelligence (CI) is a systematic and ethical program for gathering and analyzing information about your competitors' activities and general business trends to further your own company's goals. CI allows companies to gather extensive information on their competitors and to analyze what the competition is doing in order to maintain or gain a competitive edge. In commercial business this potentially translates into millions of dollars in annual savings or losses. The Internet provides an overwhelming portal of information for CI analysis. The problem is how a company can automate the translation of voluminous information into valuable and actionable knowledge. This paper describes Project X, an agent-based data mining system specifically developed for extracting and analyzing competitive information from the Internet. Project X gathers CI information from a variety of sources including online newspapers, corporate websites, industry sector reporting sites, speech archiving sites, video news casts, stock news sites, weather sites, and rumor sites. It uses individual industry specific (e.g., pharmaceutical, financial, aerospace, etc.) commercial sector ontologies to form the knowledge filtering and discovery structures/content required to filter and identify valuable competitive knowledge. Project X is described in detail and an example competitive intelligence case is shown demonstrating the system's performance and utility for business intelligence.

  9. Business Plan Competitions: An Overview. CELCEE Digest.

    ERIC Educational Resources Information Center

    Seymour, Nicole

    This document describes business plan competitions sponsored by universities. The idea began in the early 1980s at the University of Texas when Masters in Business Administration (MBA) students created a friendly competitive activity along the lines of the law schools Moot Court competition. Later the competition became national, and then…

  10. 32 CFR 22.320 - Special competitions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 1 2014-07-01 2014-07-01 false Special competitions. 22.320 Section 22.320... REGULATIONS DoD GRANTS AND AGREEMENTS-AWARD AND ADMINISTRATION Competition § 22.320 Special competitions. Some... competed specifically among institutions of higher education. All such special competitions shall...

  11. 24 CFR 791.406 - Competition.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 4 2014-04-01 2014-04-01 false Competition. 791.406 Section 791... Authority for Housing Assistance § 791.406 Competition. (a) All budget authority allocated pursuant to § 791.403(b)(2) shall be reserved and obligated pursuant to a competition. Any such competition shall...

  12. 24 CFR 791.406 - Competition.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Competition. 791.406 Section 791... Authority for Housing Assistance § 791.406 Competition. (a) All budget authority allocated pursuant to § 791.403(b)(2) shall be reserved and obligated pursuant to a competition. Any such competition shall...

  13. 24 CFR 791.406 - Competition.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false Competition. 791.406 Section 791... Authority for Housing Assistance § 791.406 Competition. (a) All budget authority allocated pursuant to § 791.403(b)(2) shall be reserved and obligated pursuant to a competition. Any such competition shall...

  14. 24 CFR 791.406 - Competition.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Competition. 791.406 Section 791... Authority for Housing Assistance § 791.406 Competition. (a) All budget authority allocated pursuant to § 791.403(b)(2) shall be reserved and obligated pursuant to a competition. Any such competition shall...

  15. 7 CFR 3430.11 - Competition.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Competition. 3430.11 Section 3430.11 Agriculture... Pre-award: Solicitation and Application § 3430.11 Competition. (a) Standards for competition. Except..., unless restricted by statute, only after competition. (b) Exception. The NIFA ADO and the...

  16. 7 CFR 3430.11 - Competition.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Competition. 3430.11 Section 3430.11 Agriculture... Pre-award: Solicitation and Application § 3430.11 Competition. (a) Standards for competition. Except... agreements, unless restricted by statute, only after competition. (b) Exception. The CSREES ADO and...

  17. 7 CFR 3430.11 - Competition.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Competition. 3430.11 Section 3430.11 Agriculture... Pre-award: Solicitation and Application § 3430.11 Competition. (a) Standards for competition. Except..., unless restricted by statute, only after competition. (b) Exception. The NIFA ADO and the...

  18. 7 CFR 3430.11 - Competition.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Competition. 3430.11 Section 3430.11 Agriculture... Pre-award: Solicitation and Application § 3430.11 Competition. (a) Standards for competition. Except..., unless restricted by statute, only after competition. (b) Exception. The NIFA ADO and the...

  19. 32 CFR 22.320 - Special competitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 1 2012-07-01 2012-07-01 false Special competitions. 22.320 Section 22.320... REGULATIONS DoD GRANTS AND AGREEMENTS-AWARD AND ADMINISTRATION Competition § 22.320 Special competitions. Some... competed specifically among institutions of higher education. All such special competitions shall...

  20. 24 CFR 791.406 - Competition.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Competition. 791.406 Section 791... Authority for Housing Assistance § 791.406 Competition. (a) All budget authority allocated pursuant to § 791.403(b)(2) shall be reserved and obligated pursuant to a competition. Any such competition shall...

  1. 48 CFR 570.203-2 - Competition.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Competition. 570.203-2... 570.203-2 Competition. (a) Solicit at least three sources to promote competition to the maximum extent..., document the file to explain the lack of competition....

  2. 78 FR 20697 - New Competitive Product

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-05

    ... is noticing a recent Postal Service filing concerning an addition to the competitive product list... 57 to the competitive product list.\\1\\ It asserts that Priority Mail Contract 57 is a competitive... Priority Mail Contract 57 to Competitive Product List and Notice of Filing (Under Seal) of...

  3. 40 CFR 35.603 - Competitive process.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Competitive process. 35.603 Section 35... (section 104(b)(3)) § 35.603 Competitive process. EPA will award water quality cooperative agreement funds through a competitive process in accordance with national program guidance. After the competitive...

  4. 40 CFR 35.382 - Competitive process.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Competitive process. 35.382 Section 35...)(3)) § 35.382 Competitive process. State Wetlands Development Grants are awarded on a competitive... established by EPA. After the competitive process is complete, the recipient can, at its discretion,...

  5. 40 CFR 35.382 - Competitive process.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Competitive process. 35.382 Section 35...)(3)) § 35.382 Competitive process. State Wetlands Development Grants are awarded on a competitive... established by EPA. After the competitive process is complete, the recipient can, at its discretion,...

  6. 40 CFR 35.382 - Competitive process.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Competitive process. 35.382 Section 35...)(3)) § 35.382 Competitive process. State Wetlands Development Grants are awarded on a competitive... established by EPA. After the competitive process is complete, the recipient can, at its discretion,...

  7. 40 CFR 35.382 - Competitive process.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Competitive process. 35.382 Section 35...)(3)) § 35.382 Competitive process. State Wetlands Development Grants are awarded on a competitive... established by EPA. After the competitive process is complete, the recipient can, at its discretion,...

  8. Synthesising Topological Links

    PubMed Central

    Baas, Nils A.; Seeman, Nadrian C.; Stacey, Andrew

    2014-01-01

    We discuss the chemical synthesis of topological links, in particular higher order links which have the Brunnian property (namely that removal of any one component unlinks the entire system). Furthermore, we suggest how to obtain both two dimensional and three dimensional objects (surfaces and solids, respectively) which also have this Brunnian property. PMID:25678732

  9. A West African Link

    ERIC Educational Resources Information Center

    Cook, Angela; Davies, Penny

    2003-01-01

    The authors visited Ghana in West Africa to strengthen a link established the previous year as part of Channel 4's "On the Line" project. The initial link established in 1999/2000 was between an all-age special school in Enfield and a similar school in Accra. Over the course of that year further partnerships were created between five UK schools…

  10. 46 CFR Sec. 4 - Procedure for securing competitive bids.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CONTRACT-NSA-LUMPSUMREP Sec. 4 Procedure for securing competitive bids. (a) The geographical area within... Bids the NSA form entitled “Invitation for Bids, Instruction for Bidders, and Specifications for... appointed representative of the time and place of opening the “Spot Bids,” and if practicable, the...

  11. 46 CFR Sec. 4 - Procedure for securing competitive bids.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CONTRACT-NSA-LUMPSUMREP Sec. 4 Procedure for securing competitive bids. (a) The geographical area within... Bids the NSA form entitled “Invitation for Bids, Instruction for Bidders, and Specifications for... appointed representative of the time and place of opening the “Spot Bids,” and if practicable, the...

  12. 46 CFR Sec. 4 - Procedure for securing competitive bids.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACT-NSA-LUMPSUMREP Sec. 4 Procedure for securing competitive bids. (a) The geographical area within... Bids the NSA form entitled “Invitation for Bids, Instruction for Bidders, and Specifications for... appointed representative of the time and place of opening the “Spot Bids,” and if practicable, the...

  13. 46 CFR Sec. 4 - Procedure for securing competitive bids.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CONTRACT-NSA-LUMPSUMREP Sec. 4 Procedure for securing competitive bids. (a) The geographical area within... Bids the NSA form entitled “Invitation for Bids, Instruction for Bidders, and Specifications for... appointed representative of the time and place of opening the “Spot Bids,” and if practicable, the...

  14. 46 CFR Sec. 4 - Procedure for securing competitive bids.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CONTRACT-NSA-LUMPSUMREP Sec. 4 Procedure for securing competitive bids. (a) The geographical area within... Bids the NSA form entitled “Invitation for Bids, Instruction for Bidders, and Specifications for... appointed representative of the time and place of opening the “Spot Bids,” and if practicable, the...

  15. Learning Competition and Business Restructuring in the Enlarging EU

    ERIC Educational Resources Information Center

    Schienstock, Gerd

    2004-01-01

    The growing importance of learning as the key competition criterion obliges companies to undertake holistic and integrated restructuring to maintain or improve their market position. Such a renewal approach includes a focus on innovation as a strategic goal, intelligent use of modern ICT, development of decentralised organisation forms,…

  16. Arizona's Capstone for a Competitive Edge--1989. Executive Summary.

    ERIC Educational Resources Information Center

    Dunn, Kathy

    Capstone for a Competitive Edge Summer Camp--1989 was a pilot program formed with input by business and industry, rural vocational educators, and the rural advisory council in conjunction with the Arizona Department of Education and the Arizona Center for Vocational Education. The program's primary intent was to meet the needs of rural vocational…

  17. Form und Sinn: Sprachwissenschaftliche Betrachtungen (Form and Meaning: Linguistic Observations).

    ERIC Educational Resources Information Center

    Jakobson, Roman

    This collection of 14 papers and articles by Roman Jakobson contains works written and published between 1931 and 1970 which deal either with global aspects of language or with specific grammatical issues. The collection emphasizes Jakobson's concern for finding the links between form and meaning in language. The text is entirely in German with…

  18. Effectiveness of national evidence-based medicine competition in Taiwan

    PubMed Central

    2013-01-01

    Background Competition and education are intimately related and can be combined in many ways. The role of competition in medical education of evidence-based medicine (EBM) has not been investigated. In order to enhance the dissemination and implementation of EBM in Taiwan, EBM competitions have been established among healthcare professionals. This study was to evaluate the impact of competition in EBM learning. Methods The EBM competition used PICO (patient, intervention, comparison, and outcome) queries to examine participants’ skills in framing an answerable question, literature search, critical appraisal and clinical application among interdisciplinary teams. A structured questionnaire survey was conducted to investigate EBM among participants in the years of 2009 and 2011. Participants completed a baseline questionnaire survey at three months prior to the competition and finished the same questionnaire right after the competition. Results Valid questionnaires were collected from 358 participants, included 162 physicians, 71 nurses, 101 pharmacists, and 24 other allied healthcare professionals. There were significant increases in participants’ knowledge of and skills in EBM (p < 0.001). Their barriers to literature searching and forming answerable questions significantly decreased (p < 0.01). Furthermore, there were significant increases in their access to the evidence-based retrieval databases, including the Cochrane Library (p < 0.001), MD Consult (p < 0.001), ProQuest (p < 0.001), UpToDate (p = 0.001), CINAHL (p = 0.001), and MicroMedex (p = 0.024). Conclusions The current study demonstrates a method that successfully enhanced the knowledge of, skills in, and behavior of EBM. The data suggest competition using PICO queries may serve as an effective way to facilitate the learning of EBM. PMID:23651869

  19. Game on: creating competitive advantages.

    PubMed

    Riskind, Patricia; Foreman, M Shane

    2004-01-01

    Whether you are opening a new imaging center or trying to keep an existing center competitive, there are 3 critical factors: customer service, marketing, and a "what's next?" attitude. Customer service: Outstanding customer service is what sticks in the minds of referring physicians and patients. Not only does providing better service differentiate you from the competition, but it also boosts employee morale and motivates people to acquire new skills. Marketing: From the front office staff to the radiologists,promoting the center should be part of every employee's job description. Simply paying lip service to the concept of marketing will not cut it. A "what's next?" attitude: Complacency is a luxury that does not exist in today's competitive health care arena. Three facilities provide examples of how these factors applied to their success.

  20. Molecular Mechanics of Tip-Link Cadherins

    NASA Astrophysics Data System (ADS)

    Sotomayor, Marcos; Weihofen, Wilhelm A.; Gaudet, Rachelle; Corey, David P.

    2011-11-01

    The hair-cell tip link, a fine filament directly conveying force to mechanosensitive transduction channels, is likely composed of two proteins, protocadherin-15 and cadherin-23, whose mutation causes deafness. However, their complete molecular structure, elasticity, and deafness-related structural defects remain largely unknown. We present crystal structures of extracellular (EC) tip-link cadherin repeats involved in hereditary deafness and tip link formation. In addition, we show that the deafness mutation D101G, in the linker region between the repeats EC1 and EC2 of cadherin-23, causes a slight bend between repeats and decreases Ca2+ affinity. Molecular dynamics simulations suggest that tip-link cadherin repeats are stiff and that either removing Ca2+ or mutating Ca2+-binding residues reduces rigidity and unfolding strength. The structures and simulations also suggest mechanisms underlying inherited deafness and how cadherin-23 may bind with protocadherin-15 to form the tip link.

  1. Competitive strategies differentiate closely related species of marine actinobacteria.

    PubMed

    Patin, Nastassia V; Duncan, Katherine R; Dorrestein, Pieter C; Jensen, Paul R

    2016-02-01

    Although competition, niche partitioning, and spatial isolation have been used to describe the ecology and evolution of macro-organisms, it is less clear to what extent these principles account for the extraordinary levels of bacterial diversity observed in nature. Ecological interactions among bacteria are particularly challenging to address due to methodological limitations and uncertainties over how to recognize fundamental units of diversity and link them to the functional traits and evolutionary processes that led to their divergence. Here we show that two closely related marine actinomycete species can be differentiated based on competitive strategies. Using a direct challenge assay to investigate inhibitory interactions with members of the bacterial community, we observed a temporal difference in the onset of inhibition. The majority of inhibitory activity exhibited by Salinispora arenicola occurred early in its growth cycle and was linked to antibiotic production. In contrast, most inhibition by Salinispora tropica occurred later in the growth cycle and was more commonly linked to nutrient depletion or other sources. Comparative genomics support these differences, with S. arenicola containing nearly twice the number of secondary metabolite biosynthetic gene clusters as S. tropica, indicating a greater potential for secondary metabolite production. In contrast, S. tropica is enriched in gene clusters associated with the acquisition of growth-limiting nutrients such as iron. Coupled with differences in growth rates, the results reveal that S. arenicola uses interference competition at the expense of growth, whereas S. tropica preferentially employs a strategy of exploitation competition. The results support the ecological divergence of two co-occurring and closely related species of marine bacteria by providing evidence they have evolved fundamentally different strategies to compete in marine sediments.

  2. Effects of Competition on the Cost and Quality of Inpatient Rehabilitation Care under Prospective Payment

    PubMed Central

    Colla, Carrie Hoverman; Escarce, José J; Buntin, Melinda Beeuwkes; Sood, Neeraj

    2010-01-01

    Objective To determine the effect of competition in postacute care (PAC) markets on resource intensity and outcomes of care in inpatient rehabilitation facilities (IRFs) after prospective payment was implemented. Data Sources Medicare claims, Provider of Services file, Enrollment file, Area Resource file, Minimum Data Set. Study Design We created an exogenous measure of competition based on patient travel distances and used instrumental variables models to estimate the effect of competition on inpatient rehabilitation costs, length of stay, and death or institutionalization. Data Extraction Methods A file was constructed linking data for Medicare patients discharged from acute care between 2002 and 2003 and admitted to an IRF with a diagnosis of hip fracture or stroke. Principal Findings Competition had different effects on treatment intensity and outcomes for hip fracture and stroke patients. In the treatment of hip fracture, competition increased costs and length of stay, while increasing rates of death or institutionalization. In the treatment of stroke, competition decreased costs and length of stay and produced inferior outcomes. Conclusions The effects of competition in PAC markets may vary by condition. It is important to study the effects of competition by diagnostic condition and to study the effects across populations that vary in severity. Our finding that higher competition under prospective payment led to worse IRF outcomes raises concerns and calls for additional research. PMID:21029086

  3. Can NCLB Survive the Competitiveness Competition? Education Outlook. Number 2

    ERIC Educational Resources Information Center

    Hess, Frederick M.; Rotherham, Andrew J.

    2007-01-01

    Some see the George W. Bush administration's American Competitiveness Initiative (ACI) as the perfect complement to the No Child Left Behind Act's (NCLB) equity focus. The authors believe, however, that the prospects for synergy of these two agendas are not bright. In this essay, the authors discuss the history behind NCLB and the ACI, and argue…

  4. Knee pain in competitive swimming.

    PubMed

    Rodeo, S A

    1999-04-01

    The high volume of training in competitive swimming results in cumulative overload injuries. Knee pain ranks second to shoulder pain as a common complaint in competitive swimmers. Most knee pain occurs on the medial side of the knee and, most commonly, in breaststroke swimmers; however, knee pain may accompany all strokes. This article reviews the incidence of knee pain, the biomechanic and anatomic factors predisposing to injury, specific injury patterns, injury diagnosis, and the treatment and prevention of injury to the knee in swimmers. PMID:10230572

  5. Active superconducting devices formed of thin films

    DOEpatents

    Martens, Jon S.; Beyer, James B.; Nordman, James E.; Hohenwarter, Gert K. G.

    1991-05-28

    Active superconducting devices are formed of thin films of superconductor which include a main conduction channel which has an active weak link region. The weak link region is composed of an array of links of thin film superconductor spaced from one another by voids and selected in size and thickness such that magnetic flux can propagate across the weak link region when it is superconducting. Magnetic flux applied to the weak link region will propagate across the array of links causing localized loss of superconductivity in the links and changing the effective resistance across the links. The magnetic flux can be applied from a control line formed of a superconducting film deposited coplanar with the main conduction channel and weak link region on a substrate. The devices can be formed of any type to superconductor but are particularly well suited to the high temperature superconductors since the devices can be entirely formed from coplanar films with no overlying regions. The devices can be utilized for a variety of electrical components, including switching circuits, amplifiers, oscillators and modulators, and are well suited to microwave frequency applications.

  6. 23 CFR 636.404 - Can a competitive range be used to limit competition?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Can a competitive range be used to limit competition... used to limit competition? If the solicitation notifies offerors that the competitive range can be... permit an efficient competition. However, you must provide written notice to any offeror whose...

  7. 23 CFR 636.404 - Can a competitive range be used to limit competition?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Can a competitive range be used to limit competition... used to limit competition? If the solicitation notifies offerors that the competitive range can be... permit an efficient competition. However, you must provide written notice to any offeror whose...

  8. 23 CFR 636.404 - Can a competitive range be used to limit competition?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Can a competitive range be used to limit competition... used to limit competition? If the solicitation notifies offerors that the competitive range can be... permit an efficient competition. However, you must provide written notice to any offeror whose...

  9. 23 CFR 636.404 - Can a competitive range be used to limit competition?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Can a competitive range be used to limit competition... used to limit competition? If the solicitation notifies offerors that the competitive range can be... permit an efficient competition. However, you must provide written notice to any offeror whose...

  10. 76 FR 1642 - Notice of Availability of Calendar Year 2011 Competitive Grant Funds

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-11

    ... (NIC; RFP Form- H) to participate in the competitive grants process. The deadline for filing the NIC is.... The dates shown in this notice for filing the NIC and the grant proposals supersede the dates in the... Applicants who may submit a NIC and a grant proposal to participate in the competitive grants process:...

  11. 46 CFR Sec. 2 - Use of contract for competitive bid and negotiated price awards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... LUMP SUM REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 2 Use of contract for competitive bid and negotiated price awards. (a) The NSA-LUMPSUMREP Contract is a Master form of fixed price contract and is applicable to... awarded under the NSA-LUMPSUMREP Contract must be awarded upon the basis of competitive bids....

  12. 46 CFR Sec. 2 - Use of contract for competitive bid and negotiated price awards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... LUMP SUM REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 2 Use of contract for competitive bid and negotiated price awards. (a) The NSA-LUMPSUMREP Contract is a Master form of fixed price contract and is applicable to... awarded under the NSA-LUMPSUMREP Contract must be awarded upon the basis of competitive bids....

  13. 46 CFR Sec. 2 - Use of contract for competitive bid and negotiated price awards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... LUMP SUM REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 2 Use of contract for competitive bid and negotiated price awards. (a) The NSA-LUMPSUMREP Contract is a Master form of fixed price contract and is applicable to... awarded under the NSA-LUMPSUMREP Contract must be awarded upon the basis of competitive bids....

  14. Linking to the Future

    NASA Astrophysics Data System (ADS)

    Moore, John W.

    1999-09-01

    my copy of JCE in the mail each month, and I expect you do too. I can glance at the cover to get an overview of an issue's content, and I usually am enticed inside by intriguing cover art. I can scan the table of contents to find articles I want to read, or I can just browse through the issue to see what looks interesting. Usually the editors have juxtaposed related articles so that I often find a small treasure trove. The printed Journal is quite portable and can be read in a car or airplane. It will last a long time, and until the paper deteriorates, I will never have a problem reading back issues. I have almost every issue from the first day I subscribed and have even added some older ones from collections of retired colleagues who no longer had shelf space for them. I certainly would not want to give up my printed copies, and I want to keep getting them. I find that JCE Online provides a different kind of resource that is equally valuable. It contains more information, and information that is more appropriate in electronic form. It links related ideas into a much more complex web of information than is possible in print. And it opens pathways to lots of information that is not part of JCE but resides elsewhere. Using this issue as an example, let's take a tour of what JCE Online can do.

    • Point your Web browser to http://jchemed.chem.wisc.edu
    • Click on Journal and then on Current Issue (unless September 1999 is no longer the current issue, in which case you will find it in Past Issues).
    • In the table of contents, find the article "UV Catalysis, Cyanotype Photography, and Sunscreens". Click on the title.
    • When the abstract appears, click on Full Text (PDF) to see the article, just as it appears on page 1199 in this issue.
    • When you are prompted, enter the name and subscriber number from your address label.
    • At the end of the article you will find that supplementary materials are available (including a procedure for testing

    • Fiber optic communication links

      SciTech Connect

      Meyer, R. H.

      1980-01-01

      Fiber optics is a new, emerging technology which offers relief from many of the problems which limited past communications links. Its inherent noise immunity and high bandwidth open the door for new designs with greater capabilities. Being a new technology, certain problems can be encountered in specifying and installing a fiber optic link. A general fiber optic system is discussed with emphasis on the advantages and disadvantages. It is not intended to be technical in nature, but a general discussion. Finally, a general purpose prototype Sandia communications link is presented.

    • Competition of the connectivity with the local and the global order in polymer melts and crystals

      SciTech Connect

      Bernini, S.; Puosi, F.; Barucco, M.; Leporini, D.

      2013-11-14

      The competition between the connectivity and the local or global order in model fully flexible chain molecules is investigated by molecular-dynamics simulations. States with both missing (melts) and high (crystal) global order are considered. Local order is characterized within the first coordination shell (FCS) of a tagged monomer and found to be lower than in atomic systems in both melt and crystal. The role played by the bonds linking the tagged monomer to FCS monomers (radial bonds), and the bonds linking two FCS monomers (shell bonds) is investigated. The detailed analysis in terms of Steinhardt's orientation order parameters Q{sub l} (l = 2 − 10) reveals that increasing the number of shell bonds decreases the FCS order in both melt and crystal. Differently, the FCS arrangements organize the radial bonds. Even if the molecular chains are fully flexible, the distribution of the angle formed by adjacent radial bonds exhibits sharp contributions at the characteristic angles θ ≈ 70°, 122°, 180°. The fractions of adjacent radial bonds with θ ≈ 122°, 180° are enhanced by the global order of the crystal, whereas the fraction with 70° ≲ θ ≲ 110° is nearly unaffected by the crystallization. Kink defects, i.e., large lateral displacements of the chains, are evidenced in the crystalline state.

    • Behavioral contrast in competitive and noncompetitive environments.

      PubMed

      Dougan, J D; McSweeney, F K; Farmer-Dougan, V A

      1986-09-01

      Three experiments examined the effects of opportunities for an alternative response (drinking) on positive behavioral contrast of rats' food-reinforced bar pressing. In both Experiments 1 and 2 the baseline multiple variable-interval schedules were rich (variable interval 10-s), and contrast was examined both with and without a water bottle present. In Experiment 1, the rats were not water deprived. When one component of the multiple schedule was changed to extinction, the rate of bar pressing increased in the constant component (positive behavioral contrast). The magnitude of contrast was larger when the bottle was absent than when it was present, as predicted by the matching law. Drinking did not shift from the constant variable-interval component to the extinction component, as might have been expected from competition theory. In Experiment 2, the rats were water deprived. Contrast was larger when the bottle was present than when it was absent, and drinking did shift to the extinction component, as predicted by competition theory. In Experiment 3, water-deprived rats responded on leaner multiple variable-interval schedules (60-s) in the presence of a water bottle. When one component was changed to extinction, contrast did not occur, and drinking did not shift to the extinction component. The present results suggest that there are at least two different sources of behavioral contrast: "competitive" contrast, observed when an alternative response occurs with high probability, and "noncompetitive" contrast, observed when an alternative response occurs with low probability. The results, in conjunction with earlier studies, also suggest that the form of the alternative response and the rate of food reinforcement provided by the multiple schedule combine to determine the amount of contrast.

    • The competitive advantage of corporate philanthropy.

      PubMed

      Porter, Michael E; Kramer, Mark R

      2002-12-01

      When it comes to philanthropy, executives increasingly see themselves as caught between critics demanding ever higher levels of "corporate social responsibility" and investors applying pressure to maximize short-term profits. In response, many companies have sought to make their giving more strategic, but what passes for strategic philanthropy is almost never truly strategic, and often isn't particularly effective as philanthropy. Increasingly, philanthropy is used as a form of public relations or advertising, promoting a company's image through high-profile sponsorships. But there is a more truly strategic way to think about philanthropy. Corporations can use their charitable efforts to improve their competitive context--the quality of the business environment in the locations where they operate. Using philanthropy to enhance competitive context aligns social and economic goals and improves a company's long-term business prospects. Addressing context enables a company to not only give money but also leverage its capabilities and relationships in support of charitable causes. The produces social benefits far exceeding those provided by individual donors, foundations, or even governments. Taking this new direction requires fundamental changes in the way companies approach their contribution programs. For example, philanthropic investments can improve education and local quality of life in ways that will benefit the company. Such investments can also improve the company's competitiveness by contributing to expanding the local market and helping to reduce corruption in the local business environment. Adopting a context-focused approach goes against the grain of current philanthropic practice, and it requires a far more disciplined approach than is prevalent today. But it can make a company's philanthropic activities far more effective. PMID:12510538

    • The competitive advantage of corporate philanthropy.

      PubMed

      Porter, Michael E; Kramer, Mark R

      2002-12-01

      When it comes to philanthropy, executives increasingly see themselves as caught between critics demanding ever higher levels of "corporate social responsibility" and investors applying pressure to maximize short-term profits. In response, many companies have sought to make their giving more strategic, but what passes for strategic philanthropy is almost never truly strategic, and often isn't particularly effective as philanthropy. Increasingly, philanthropy is used as a form of public relations or advertising, promoting a company's image through high-profile sponsorships. But there is a more truly strategic way to think about philanthropy. Corporations can use their charitable efforts to improve their competitive context--the quality of the business environment in the locations where they operate. Using philanthropy to enhance competitive context aligns social and economic goals and improves a company's long-term business prospects. Addressing context enables a company to not only give money but also leverage its capabilities and relationships in support of charitable causes. The produces social benefits far exceeding those provided by individual donors, foundations, or even governments. Taking this new direction requires fundamental changes in the way companies approach their contribution programs. For example, philanthropic investments can improve education and local quality of life in ways that will benefit the company. Such investments can also improve the company's competitiveness by contributing to expanding the local market and helping to reduce corruption in the local business environment. Adopting a context-focused approach goes against the grain of current philanthropic practice, and it requires a far more disciplined approach than is prevalent today. But it can make a company's philanthropic activities far more effective.

    • Unbundling services in a competitive electricity market

      SciTech Connect

      Spiller, P.T.

      1996-03-01

      The purpose of this presentation is to provide an in-depth discussion of the possible evolution of unbundling of services in a competitive environment. The author discusses unbundling from both a technical/engineering and an economic perspective. The main thrust of the talk is threefold: (a) that in the long run the potential for unbundling of services is extremely large from an engineering perspective; (b) that the form of the initial industry structure will have an important impact on the extent of service unbundling; and (c) that unbundling of wholesale related services is where most of the initial demand will be. (A) Engineering Perspectives on Unbundling: A large proportion of ancillary services can be provided in a competitive framework with current technologies. The author discusses those that current technologies may not facilitate such a decentralized approach. (B) The relation between unbundling and industry structure: Not all industry structures provide the same incentives for the independent service operator (ISO) to unbundle its services. Direct access provides incentives to suppliers to provide ancillary services to its own customers. Such incentive is limited by more centralized organizational modes. (C) Different Demand for Wholesale and Retail Unbundling: Lessons from other sectors: The experience with unbundling in telecommunications is illuminating. Wholesale unbundling, when allowed, has turned out to be a key component of competition. Retail unbundling is limited by customer sophistication. Indeed, retail unbundling will evolve in waves: initially retail customers will demand bundled services, as complexity of services may overwhelm customer sophistication. As customer sophistication increases and technology improves, the demand for partial unbundling increases providing opportunities for speicialized firms to provide partially unbundled services.

  1. Maternal effects, but no good or compatible genes for sperm competitiveness in Australian crickets.

    PubMed

    Dowling, Damian K; Nystrand, Magdalena; Simmons, Leigh W

    2010-05-01

    Explanations for the evolution of polyandry often center on the idea that females garner genetic benefits for their offspring by mating multiply. Furthermore, postcopulatory processes are thought to be fundamental to enabling polyandrous females to screen for genetic quality. Much attention has focused on the potential for polyandrous females to accrue such benefits via a sexy- or good-sperm mechanism, whereby additive variation exists among males in sperm competitiveness. Likewise, attention has focused on an alternative model, in which offspring quality (in this context, the sperm competitiveness of sons) hinges on an interaction between parental haplotypes (genetic compatibility). Sperm competitiveness that is contingent on parental compatibility will exhibit nonadditive genetic variation. We tested these models in the Australian cricket, Teleogryllus oceanicus, using a design that allowed us to partition additive, nonadditive genetic, and parental variance for sperm competitiveness. We found an absence of additive and nonadditive genetic variance in this species, challenging the direct relevance of either model to the evolution of sperm competitiveness in particular, and polyandry in general. Instead, we found maternal effects that were possibly sex-linked or cytoplasmically linked. We also found effects of focal male age on sperm competitiveness, with small increments in age conferring more competitive sperm. PMID:20002162

  2. Species clustering in competitive Lotka-Volterra models.

    PubMed

    Pigolotti, Simone; López, Cristóbal; Hernández-García, Emilio

    2007-06-22

    We study the properties of general Lotka-Volterra models with competitive interactions. The intensity of the competition depends on the position of species in an abstract niche space through an interaction kernel. We show analytically and numerically that the properties of these models change dramatically when the Fourier transform of this kernel is not positive definite, due to a pattern-forming instability. We estimate properties of the species distributions, such as the steady number of species and their spacings, for different types of interactions, including stretched exponential and constant kernels.

  3. Future survival requires competitive skills

    SciTech Connect

    Adam, P.J.

    1996-10-01

    The companies that will succeed in the global power business in 25 years will be those that best understand the productivity implications of the current power game. In the competitive free market for electricity, the inefficient will be driven out. This will include the developer that is unable to achieve higher productivity in developing and financing projects, the engineer-constructor that longs for the old risk-free, cost-plus environment and the trading company that fails to enter into new relationships with the most productive companies in the world. Also in jeopardy will be the operator who can`t reduce O and M costs and the manufacturer who is unable to control overhead or labor costs. Succeeding will be all about productivity. Free market competition drives productivity improvement. In a competitive environment, companies must operate at a more efficient level. The US learned this accidentally through the Public Utilities Regulatory Policies Act, getting us a side benefit of free market competition and lower electricity prices. In other countries the practice of socialism and its final bankruptcy forced adjustments to free market policies.

  4. Raising Economic Competitiveness with Education.

    ERIC Educational Resources Information Center

    Silberman, Harry F.

    The current school reform movement has been plagued by three false assumptions. The first of these postulates that more academic requirements will strengthen the minds of students, improve their reasoning, prepare them for a rapidly changing economy, and make the U.S. economy more competitive. Although it is true that the workers of the future…

  5. An Amusement Park Physics Competition

    ERIC Educational Resources Information Center

    Moll, Rachel F.

    2010-01-01

    Amusement park physics is a popular way to reinforce physics concepts and to motivate physics learners. This article describes a novel physics competition where students use simple tools to take amusement park ride measurements and use the data to answer challenging exam questions. Research into the impact of participating in the competition…

  6. Teaching the Values of Competition

    ERIC Educational Resources Information Center

    Buyer, Paul

    2005-01-01

    The author of this paper first learned about the values of competition as a member of the 1989 Star of Indiana Drum and Bugle Corps. Because they played more than thirty shows that summer, it was common to compete two nights in a row. He vividly remembers one such occasion. Their first show was outstanding, and they finished second. Everyone was…

  7. Competitive economics of nuclear power

    SciTech Connect

    Hellman, R.

    1981-03-02

    Some 12 components of a valid study of the competitive economics of a newly ordered nuclear power plant are identified and explicated. These are then used to adjust the original cost projections of four authoritative studies of nuclear and coal power economics.

  8. Competition with Charters Motivates Districts

    ERIC Educational Resources Information Center

    Holley, Marc J.; Lueken, Martin F.; Egalite, Anna J.

    2013-01-01

    Proponents of market-based education reform often argue that introducing charter schools and other school choice policies creates a competitive dynamic that will prompt low-performing districts to improve their practice. Rather than simply providing an alternative to neighborhood public schools for a handful of students, the theory says, school…

  9. Does market competition explain fairness?

    PubMed

    Descioli, Peter

    2013-02-01

    The target article by Baumard et al. uses their previous model of bargaining with outside options to explain fairness and other features of human sociality. This theory implies that fairness judgments are determined by supply and demand but humans often perceive prices (divisions of surplus) in competitive markets to be unfair.

  10. Clean Energy Business Plan Competition

    SciTech Connect

    Maxted, Sara Jane; Lojewski, Brandon; Scherson, Yaniv

    2012-01-01

    Top Students Pitch Clean Energy Business Plans The six regional finalists of the National Clean Energy Business Plan Competition pitched their business plans to a panel of judges June 13 in Washington, D.C. The expert judges announced NuMat Technologies from Northwestern University as the grand prize winner.

  11. Competitive Cooperation: The Iceberg Profile.

    ERIC Educational Resources Information Center

    Vaughan, Jerry L.

    Competitive athletes' scores on the Profile of Mood States (POMS) test create an iceberg-like pattern known as the "Iceberg Profile." Their scores for tension, depression, anger, fatigue, and confusion are low while their scores on vigor juts upward creating the "Iceberg Profile." Persons in a cooperative relationship are often competing against…

  12. Geographic Proximity and Enrollment Competition.

    ERIC Educational Resources Information Center

    Zammuto, Raymond F.

    The use of a measure of geographic proximity to help explain enrollment competition among postsecondary institutions was investigated. The measure, the number of miles between institutions, was obtained by determining the longitude and latitude coordinates for about 99% of the schools in the Higher Education General Information System universe.…

  13. Assessing the New Competitive Landscape.

    ERIC Educational Resources Information Center

    Blustain, Harvey; Goldstein, Philip; Lozier, Gregory

    1998-01-01

    Argues that complex forces (new delivery technologies, changing demographics, emergence of corporate universities, global economy) have created a new, competitive landscape for higher education that forces institutions to think methodically about how to respond. A framework for college planning, incorporating three critical components, is…

  14. A Sinking Feeling about Competition.

    ERIC Educational Resources Information Center

    Cirasuolo, Joseph J.

    2001-01-01

    A competitive school ambience will further distinguish winners from losers in an increasingly fractured and stratified society. Disadvantaged students have little chance to win the standards game. Educators should examine the gilded age's hypocrisy; what gallantry existed the night the Titanic sank applied only to first-class female passengers.…

  15. Economic Competitiveness: A Campaign Primer

    ERIC Educational Resources Information Center

    Fischer, Karin

    2008-01-01

    With the dollar's continued swoon and grim news on the job front, American economic competitiveness has become a central theme in the presidential election. Stumping in Ohio and Pennsylvania, old-line industrial states hit hard by the flight of manufacturing jobs, Democrats Hillary Rodham Clinton and Barack Obama have called for renegotiating the…

  16. Clean Energy Business Plan Competition

    ScienceCinema

    Maxted, Sara Jane; Lojewski, Brandon; Scherson, Yaniv

    2016-07-12

    Top Students Pitch Clean Energy Business Plans The six regional finalists of the National Clean Energy Business Plan Competition pitched their business plans to a panel of judges June 13 in Washington, D.C. The expert judges announced NuMat Technologies from Northwestern University as the grand prize winner.

  17. Competition in a Social Structure

    NASA Astrophysics Data System (ADS)

    Legara, Erika Fille; Longjas, Anthony; Batac, Rene

    Complex adaptive agents develop strategies in the presence of competition. In modern human societies, there is an inherent sense of locality when describing inter-agent dynamics because of its network structure. One then wonders whether the traditional advertising schemes that are globally publicized and target random individuals are as effective in attracting a larger portion of the population as those that take advantage of local neighborhoods, such as "word-of-mouth" marketing schemes. Here, we demonstrate using a differential equation model that schemes targeting local cliques within the network are more successful at gaining a larger share of the population than those that target users randomly at a global scale (e.g., television commercials, print ads, etc.). This suggests that success in the competition is dependent not only on the number of individuals in the population but also on how they are connected in the network. We further show that the model is general in nature by considering examples of competition dynamics, particularly those of business competition and language death.

  18. Wallops Low Elevation Link Analysis for the Constellation Launch/Ascent Links

    NASA Technical Reports Server (NTRS)

    Cheung, Keith; Ho, C.; Kantak, A.; Lee, C.; Tye, R.; Richards, E.; Sham, C.; Schlesinger, A.; Barritt, B.

    2011-01-01

    To execute the President's Vision for Space Exploration, the Constellation Program (CxP) was formed to build the next generation spacecraft Orion and launch vehicles Ares, to transport human and cargo to International Space Station (ISS), moon, and Mars. This paper focuses on the detailed link analysis for Orion/Ares s launch and ascent links with Wallops 11.3m antenna (1) Orion's Dissimilar Voice link: 10.24 Kbps, 2-way (2) Ares Developmental Flight Instrument link, 20 Mbps, downlink. Three launch trajectories are considered: TD7-E, F (Feb), and G (Aug). In certain launch scenarios, the critical events of main engine cutoff (MECO) and Separation occur during the low elevation regime of WFF s downrange -- less than 5 degree elevation angle. The goal of the study is to access if there is enough link margins for WFF to track the DV and DFI links.

  19. The NEC Link Scheme

    ERIC Educational Resources Information Center

    Noakes, Peter

    1976-01-01

    Describes the operation of the National Electronics Council (NEC) Link Scheme for schools in Great Britain. The service is intended to provide technical assistance, information concerning surplus equipment, and guest speakers for school aspiring professional electronic counsel. (CP)

  20. The Link: Business, Education.

    ERIC Educational Resources Information Center

    AGB Reports, 1984

    1984-01-01

    An excerpt from "Corporate and Campus Cooperation: An Action Agenda" (a report from the Business-Higher Education Forum) explains some methods for strengthening the link between the business and education communities. (Author/MLW)

  1. Linked for Learning.

    ERIC Educational Resources Information Center

    Freeman, Laurie

    1996-01-01

    The Northern Tier Distance Learning Consortium links six high schools and three colleges in northeastern Pennsylvania. Indiana students participated in an interactive distance-learning program that focused on underwater exploration. (MLF)

  2. Thermo-cross-linked elastomeric opal films.

    PubMed

    Schäfer, Christian G; Viel, Benjamin; Hellmann, Goetz P; Rehahn, Matthias; Gallei, Markus

    2013-11-13

    An efficient and convenient thermal cross-linking protocol in elastomeric opal films leading to fully reversible and stretch-tunable optical materials is reported. In this study, functional monodisperse core-shell particles were arranged in a face-centered cubic (fcc) lattice structure by a melt flow process. A problem up to now was that un-cross-linked films could not be drawn fully reversibly and hence lost their optical and mechanical performance. After thermal cross-linking reaction, the obtained films can be drawn like rubbers and the color of their Bragg reflection changes because of controlled lattice deformation, which makes the cross-linked films mechanochromic sensors. Different techniques were developed for the cross-linking of the films a posteriori, after their preparation in the melt flow process. A photo-cross-linking approach was reported earlier. This study now deals with a very efficient thermo-cross-linking approach based on the chemistry of hydroxyl- and isocyanate-functionalities that form urethane bridges. The focus of the present work is the mechanism and efficiency of this cross-linking process for elastomeric opal films with excellent mechanical and optical properties. PMID:24134322

  3. Mitochondrial function in the brain links anxiety with social subordination

    PubMed Central

    Hollis, Fiona; van der Kooij, Michael A.; Zanoletti, Olivia; Lozano, Laura; Cantó, Carles; Sandi, Carmen

    2015-01-01

    Dominance hierarchies are integral aspects of social groups, yet whether personality traits may predispose individuals to a particular rank remains unclear. Here we show that trait anxiety directly influences social dominance in male outbred rats and identify an important mediating role for mitochondrial function in the nucleus accumbens. High-anxious animals that are prone to become subordinate during a social encounter with a low-anxious rat exhibit reduced mitochondrial complex I and II proteins and respiratory capacity as well as decreased ATP and increased ROS production in the nucleus accumbens. A causal link for these findings is indicated by pharmacological approaches. In a dyadic contest between anxiety-matched animals, microinfusion of specific mitochondrial complex I or II inhibitors into the nucleus accumbens reduced social rank, mimicking the low probability to become dominant observed in high-anxious animals. Conversely, intraaccumbal infusion of nicotinamide, an amide form of vitamin B3 known to enhance brain energy metabolism, prevented the development of a subordinate status in high-anxious individuals. We conclude that mitochondrial function in the nucleus accumbens is crucial for social hierarchy establishment and is critically involved in the low social competitiveness associated with high anxiety. Our findings highlight a key role for brain energy metabolism in social behavior and point to mitochondrial function in the nucleus accumbens as a potential marker and avenue of treatment for anxiety-related social disorders. PMID:26621716

  4. Mitochondrial function in the brain links anxiety with social subordination.

    PubMed

    Hollis, Fiona; van der Kooij, Michael A; Zanoletti, Olivia; Lozano, Laura; Cantó, Carles; Sandi, Carmen

    2015-12-15

    Dominance hierarchies are integral aspects of social groups, yet whether personality traits may predispose individuals to a particular rank remains unclear. Here we show that trait anxiety directly influences social dominance in male outbred rats and identify an important mediating role for mitochondrial function in the nucleus accumbens. High-anxious animals that are prone to become subordinate during a social encounter with a low-anxious rat exhibit reduced mitochondrial complex I and II proteins and respiratory capacity as well as decreased ATP and increased ROS production in the nucleus accumbens. A causal link for these findings is indicated by pharmacological approaches. In a dyadic contest between anxiety-matched animals, microinfusion of specific mitochondrial complex I or II inhibitors into the nucleus accumbens reduced social rank, mimicking the low probability to become dominant observed in high-anxious animals. Conversely, intraaccumbal infusion of nicotinamide, an amide form of vitamin B3 known to enhance brain energy metabolism, prevented the development of a subordinate status in high-anxious individuals. We conclude that mitochondrial function in the nucleus accumbens is crucial for social hierarchy establishment and is critically involved in the low social competitiveness associated with high anxiety. Our findings highlight a key role for brain energy metabolism in social behavior and point to mitochondrial function in the nucleus accumbens as a potential marker and avenue of treatment for anxiety-related social disorders.

  5. Mitochondrial function in the brain links anxiety with social subordination.

    PubMed

    Hollis, Fiona; van der Kooij, Michael A; Zanoletti, Olivia; Lozano, Laura; Cantó, Carles; Sandi, Carmen

    2015-12-15

    Dominance hierarchies are integral aspects of social groups, yet whether personality traits may predispose individuals to a particular rank remains unclear. Here we show that trait anxiety directly influences social dominance in male outbred rats and identify an important mediating role for mitochondrial function in the nucleus accumbens. High-anxious animals that are prone to become subordinate during a social encounter with a low-anxious rat exhibit reduced mitochondrial complex I and II proteins and respiratory capacity as well as decreased ATP and increased ROS production in the nucleus accumbens. A causal link for these findings is indicated by pharmacological approaches. In a dyadic contest between anxiety-matched animals, microinfusion of specific mitochondrial complex I or II inhibitors into the nucleus accumbens reduced social rank, mimicking the low probability to become dominant observed in high-anxious animals. Conversely, intraaccumbal infusion of nicotinamide, an amide form of vitamin B3 known to enhance brain energy metabolism, prevented the development of a subordinate status in high-anxious individuals. We conclude that mitochondrial function in the nucleus accumbens is crucial for social hierarchy establishment and is critically involved in the low social competitiveness associated with high anxiety. Our findings highlight a key role for brain energy metabolism in social behavior and point to mitochondrial function in the nucleus accumbens as a potential marker and avenue of treatment for anxiety-related social disorders. PMID:26621716

  6. How does competition structure affect industry merger waves? A network analysis perspective

    NASA Astrophysics Data System (ADS)

    Hou, Rui; Yang, Jianmei; Yao, Canzhong; McKelvey, Bill

    2015-07-01

    By taking China's beer industry as an example, this paper establishes a series of industrial competition-pressure networks and examines the correlation between competition structure and merger actions. We present a cascade dynamic-merger agent-based computational model driven by competition pressure diffusion to describe the forming process of industry merger wave. The empirical analyses and agent-based computational simulation results show that the competition structure among rivals has a strong effect on the scale, the duration time, and the stability of industry merger wave. We also give explanations on why there are different simulation results between in single market competition environment and in multi-market competition environment, as well as discuss the management implications for the industry-merger policy makers and the merger-tactics decision makers that are involved in merger wave.

  7. Competitive Interactions of Garlic Mustard (Alliaria petiolata) and Damesrocket (Hesperis matronalis)

    USGS Publications Warehouse

    Leicht-Young, Stacey A.; Pavlovic, Noel B.; Adams, Jean V.

    2012-01-01

    Competitive interactions between native plants and nonnative, invasive plant species have been extensively studied; however, within degraded landscapes, the effect of interspecific interactions among invasive plants is less explored. We investigated a competitive interaction between two sympatric, invasive mustard species that have similar life history strategies and growth forms: garlic mustard and damesrocket. Greenhouse experiments using a full range of reciprocal density ratios were conducted to investigate interspecific competition. Garlic mustard had a negative effect on the final biomass, number of leaves, and relative growth rate in height of damesrocket. Survival of damesrocket was not negatively affected by interspecific competition with garlic mustard; however, garlic mustard showed higher mortality because of intraspecific competition. These results indicated that although garlic mustard has been observed to be the dominant species in this landscape, it may not completely outcompete damesrocket in all situations. Studies of invasive species in competition are important in degraded landscapes because this is the common situation in many natural areas.

  8. Dynamical coding of sensory information with competitive networks.

    PubMed

    Rabinovich, M I; Huerta, R; Volkovskii, A; Abarbanel, H D; Stopfer, M; Laurent, G

    2000-01-01

    Based on experiments with the locust olfactory system, we demonstrate that model sensory neural networks with lateral inhibition can generate stimulus specific identity-temporal patterns in the form of stimulus-dependent switching among small and dynamically changing neural ensembles (each ensemble being a group of synchronized projection neurons). Networks produce this switching mode of dynamical activity when lateral inhibitory connections are strongly non-symmetric. Such coding uses 'winner-less competitive' (WLC) dynamics. In contrast to the well known winner-take-all competitive (WTA) networks and Hopfield nets, winner-less competition represents sensory information dynamically. Such dynamics are reproducible, robust against intrinsic noise and sensitive to changes in the sensory input. We demonstrate the validity of sensory coding with WLC networks using two different formulations of the dynamics, namely the average and spiking dynamics of projection neurons (PN).

  9. Modelling Lipid Competition Dynamics in Heterogeneous Protocell Populations

    PubMed Central

    Shirt-Ediss, Ben; Ruiz-Mirazo, Kepa; Mavelli, Fabio; Solé, Ricard V.

    2014-01-01

    Recent experimental work in the field of synthetic protocell biology has shown that prebiotic vesicles are able to ‘steal’ lipids from each other. This phenomenon is driven purely by asymmetries in the physical state or composition of the vesicle membranes, and, when lipid resource is limited, translates directly into competition amongst the vesicles. Such a scenario is interesting from an origins of life perspective because a rudimentary form of cell-level selection emerges. To sharpen intuition about possible mechanisms underlying this behaviour, experimental work must be complemented with theoretical modelling. The aim of this paper is to provide a coarse-grain mathematical model of protocell lipid competition. Our model is capable of reproducing, often quantitatively, results from core experimental papers that reported distinct types vesicle competition. Additionally, we make some predictions untested in the lab, and develop a general numerical method for quickly solving the equilibrium point of a model vesicle population. PMID:25024020

  10. Modelling Lipid Competition Dynamics in Heterogeneous Protocell Populations

    NASA Astrophysics Data System (ADS)

    Shirt-Ediss, Ben; Ruiz-Mirazo, Kepa; Mavelli, Fabio; Solé, Ricard V.

    2014-07-01

    Recent experimental work in the field of synthetic protocell biology has shown that prebiotic vesicles are able to `steal' lipids from each other. This phenomenon is driven purely by asymmetries in the physical state or composition of the vesicle membranes, and, when lipid resource is limited, translates directly into competition amongst the vesicles. Such a scenario is interesting from an origins of life perspective because a rudimentary form of cell-level selection emerges. To sharpen intuition about possible mechanisms underlying this behaviour, experimental work must be complemented with theoretical modelling. The aim of this paper is to provide a coarse-grain mathematical model of protocell lipid competition. Our model is capable of reproducing, often quantitatively, results from core experimental papers that reported distinct types vesicle competition. Additionally, we make some predictions untested in the lab, and develop a general numerical method for quickly solving the equilibrium point of a model vesicle population.

  11. Modelling lipid competition dynamics in heterogeneous protocell populations.

    PubMed

    Shirt-Ediss, Ben; Ruiz-Mirazo, Kepa; Mavelli, Fabio; Solé, Ricard V

    2014-01-01

    Recent experimental work in the field of synthetic protocell biology has shown that prebiotic vesicles are able to 'steal' lipids from each other. This phenomenon is driven purely by asymmetries in the physical state or composition of the vesicle membranes, and, when lipid resource is limited, translates directly into competition amongst the vesicles. Such a scenario is interesting from an origins of life perspective because a rudimentary form of cell-level selection emerges. To sharpen intuition about possible mechanisms underlying this behaviour, experimental work must be complemented with theoretical modelling. The aim of this paper is to provide a coarse-grain mathematical model of protocell lipid competition. Our model is capable of reproducing, often quantitatively, results from core experimental papers that reported distinct types vesicle competition. Additionally, we make some predictions untested in the lab, and develop a general numerical method for quickly solving the equilibrium point of a model vesicle population. PMID:25024020

  12. Kin competition within groups: the offspring depreciation hypothesis.

    PubMed

    Ridley, J; Sutherland, W J

    2002-12-22

    Where relatives compete for the same resources (kin competition) and each obtains an equal share, this can favour the evolution of elevated dispersal rates, such that most resource competition is among non-relatives. We show that this effect evaporates as among-sibling dominance increases to the point where the allocation of resources is maximally unequal. We restore a kin-competition effect on emigration rates from dominance-ranked family groups by showing that where siblings form queues to inherit the breeding positions, the length of the queue affects the fitness of all individuals by depreciating the rank of subsequent offspring. Incorporating this 'offspring depreciation' effect decreases optimal queue lengths, increases dispersal rates and explains the otherwise paradoxical use of sinks by cooperatively breeding birds in stable environments. The offspring depreciation effect also favours the evolution of small, but consistent, clutch sizes and high reproductive skew, but constrains the evolution of alloparenting.

  13. Linked Ocean Data

    NASA Astrophysics Data System (ADS)

    Leadbetter, Adam; Arko, Robert; Chandler, Cynthia; Shepherd, Adam

    2014-05-01

    "Linked Data" is a term used in Computer Science to encapsulate a methodology for publishing data and metadata in a structured format so that links may be created and exploited between objects. Berners-Lee (2006) outlines the following four design principles of a Linked Data system: Use Uniform Resource Identifiers (URIs) as names for things. Use HyperText Transfer Protocol (HTTP) URIs so that people can look up those names. When someone looks up a URI, provide useful information, using the standards (Resource Description Framework [RDF] and the RDF query language [SPARQL]). Include links to other URIs so that they can discover more things. In 2010, Berners-Lee revisited his original design plan for Linked Data to encourage data owners along a path to "good Linked Data". This revision involved the creation of a five star rating system for Linked Data outlined below. One star: Available on the web (in any format). Two stars: Available as machine-readable structured data (e.g. An Excel spreadsheet instead of an image scan of a table). Three stars: As two stars plus the use of a non-proprietary format (e.g. Comma Separated Values instead of Excel). Four stars: As three stars plus the use of open standards from the World Wide Web Commission (W3C) (i.e. RDF and SPARQL) to identify things, so that people can point to your data and metadata. Five stars: All the above plus link your data to other people's data to provide context Here we present work building on the SeaDataNet common vocabularies served by the NERC Vocabulary Server, connecting projects such as the Rolling Deck to Repository (R2R) and the Biological and Chemical Oceanography Data Management Office (BCO-DMO) and other vocabularies such as the Marine Metadata Interoperability Ontology Register and Repository and the NASA Global Change Master Directory to create a Linked Ocean Data cloud. Publishing the vocabularies and metadata in standard RDF XML and exposing SPARQL endpoints renders them five-star Linked

  14. NEWS: Paperclip Physics: anatomy of a competition

    NASA Astrophysics Data System (ADS)

    2000-09-01

    competition allows pupils to practise these skills by doing a presentation `for real'. It also allows them to demonstrate other (perhaps previously latent) talents such as acting. And we are constantly amazed by the ingenuity that the teams use in developing interesting and convincing demonstrations. Last but definitely not least, all of us who teach physics for a living are well aware that you really have to understand something in order to be able to explain it to others. The learning process that goes on while preparing the presentation should not be underrated, nor should the sense of achievement that the presenters feel afterwards, whether they win or not. As for the teachers' workload, we are assured that frequently they have had little to do with the presentations. There was even one memorable occasion when a team was nearly withdrawn from the regional competition because their teacher had not had time to watch their demonstration. The team insisted on going ahead and won the regional final to earn themselves a trip to London! So teachers should be assured that this is not one of those competitions that will involve them in endless work---the ideas, the ingenuity and the enthusiasm come from the pupils. The 2001 competition, which is open to first-year sixth form or equivalent, is to be launched with a mailing of flyers and posters to schools in September. Details are also on the IOP website (www.iop.org/Schools/paperclip.html). The closing date will be the end of November 2000 and heats and regional finals will take place in February and early March. The Grand Final will be at the IOP headquarters in London in late March. We look forward to having entries from all over the UK and Ireland. E M Parvin Chairman of IOP Midland Branch

  15. GENE REGULATION BY MAPK SUBSTRATE COMPETITION

    PubMed Central

    Kim, Yoosik; Andreu, María José; Lim, Bomyi; Chung, Kwanghun; Terayama, Mark; Jiménez, Gerardo; Berg, Celeste A.; Lu, Hang; Shvartsman, Stanislav Y.

    2011-01-01

    SUMMARY Developing tissues are patterned by coordinated activities of signaling systems, which can be integrated by a regulatory region of a gene that binds multiple transcription factors or by a transcription factor that is modified by multiple enzymes. Based on a combination of genetic and imaging experiments in the early Drosophila embryo, we describe a signal integration mechanism that cannot be reduced to a single gene regulatory element or a single transcription factor. This mechanism relies on an enzymatic network formed by Mitogen Activated Protein Kinase (MAPK) and its substrates. Specifically, anteriorly localized MAPK substrates, such as Bicoid, antagonize MAPK-dependent downregulation of Capicua, a repressor which is involved in gene regulation along the dorsoventral axis of the embryo. MAPK substrate competition provides a basis for ternary interaction of the anterior, dorsoventral, and terminal patterning systems. A mathematical model of this interaction can explain gene expression patterns with both anteroposterior and dorsoventral polarities. PMID:21664584

  16. Interspecific competition between alien and native congeneric species

    NASA Astrophysics Data System (ADS)

    Garcia-Serrano, H.; Sans, F. X.; Escarré, J.

    2007-01-01

    A good way to check hypotheses explaining the invasion of ecosystems by exotic plants is to compare alien and native congeneric species. To test the hypothesis that invasive alien plants are more competitive than natives, we designed a replacement series experiment to evaluate interspecific competition between three Senecio species representing the same bushy life form: two alien species ( S. inaequidens and S. pterophorus, both from South Africa) and a native species from the south-east of the Iberian Peninsula and Maghreb ( S. malacitanus). While S. inaequidens is widespread throughout western Europe and is expanding towards the south of Spanish-French border, the geographical distribution of the recently introduced S. pterophorus is still limited to north-eastern Spain. Plants from each species were grown in pure and in mixed cultures with one of their congeners, and water availability was manipulated to evaluate the effects of water stress on competitive abilities. Our results show that the alien S. inaequidens is the most competitive species for all water conditions. The native S. malacitanus is more competitive that the alien S. pterophorus in water stress conditions, but this situation is reversed when water availability is not limiting.

  17. Kin composition effects on reproductive competition among queenless honeybee workers

    NASA Astrophysics Data System (ADS)

    Inbar, Shani; Katzav-Gozansky, Tamar; Hefetz, Abraham

    2008-05-01

    Kin selection and inclusive fitness theories predict that, in hopeless queenless (QL) groups, competition or cooperation will occur over male production among workers of different patrilines. Competition is expected to involve mutual inhibition of reproduction and to affect fertility advertisement. To examine kin effect on these phenomena, we studied QL groups of honeybee workers comprising three types of kin structure: groups composed of pure single patrilines, groups composed of three mixed patrilines (all originating from colonies headed by single-drone-inseminated queens), and control groups composed of bees originating from naturally mated queens. Global assessment of ovarian development, irrespective of patriline composition, revealed no differences among group types. In contrast, the performance of specific patrilines revealed that, in the three-mixed-patriline groups, some patrilines were reproductively suppressed compared to their performance when reared as a pure single patriline, resulting in an uneven share of reproduction. Analysis of the fertility signal produced by Dufour’s gland revealed kin composition effects, which may reflect the bees’ competitive efforts. Although patriline effects on worker reproductive superiority have been shown in QL colonies, we were able to investigate specific patriline performance both in competitive and noncompetitive situations here for the first time. The results are consistent with the hypothesis that reproductive and pheromonal competitions in QL groups are affected by the number of subfamilies populating a colony and that these act as coalitions. The results also emphasize that within-colony heterogeneity, in the form of multiple patrilines, has far-reaching consequences on social evolution.

  18. Kin composition effects on reproductive competition among queenless honeybee workers.

    PubMed

    Inbar, Shani; Katzav-Gozansky, Tamar; Hefetz, Abraham

    2008-05-01

    Kin selection and inclusive fitness theories predict that, in hopeless queenless (QL) groups, competition or cooperation will occur over male production among workers of different patrilines. Competition is expected to involve mutual inhibition of reproduction and to affect fertility advertisement. To examine kin effect on these phenomena, we studied QL groups of honeybee workers comprising three types of kin structure: groups composed of pure single patrilines, groups composed of three mixed patrilines (all originating from colonies headed by single-drone-inseminated queens), and control groups composed of bees originating from naturally mated queens. Global assessment of ovarian development, irrespective of patriline composition, revealed no differences among group types. In contrast, the performance of specific patrilines revealed that, in the three-mixed-patriline groups, some patrilines were reproductively suppressed compared to their performance when reared as a pure single patriline, resulting in an uneven share of reproduction. Analysis of the fertility signal produced by Dufour's gland revealed kin composition effects, which may reflect the bees' competitive efforts. Although patriline effects on worker reproductive superiority have been shown in QL colonies, we were able to investigate specific patriline performance both in competitive and noncompetitive situations here for the first time. The results are consistent with the hypothesis that reproductive and pheromonal competitions in QL groups are affected by the number of subfamilies populating a colony and that these act as coalitions. The results also emphasize that within-colony heterogeneity, in the form of multiple patrilines, has far-reaching consequences on social evolution.

  19. Information use and resource competition: an integrative framework

    PubMed Central

    Ounsley, James P.

    2016-01-01

    Organisms may reduce uncertainty regarding how best to exploit their environment by collecting information about resource distribution. We develop a model to demonstrate how competition can facilitate or constrain an individual's ability to use information when acquiring resources. As resource distribution underpins both selection on information use and the strength and nature of competition between individuals, we demonstrate interdependencies between the two that should be common in nature. Individuals in our model can search for resources either personally or by using social information. We explore selection on social information use across a comprehensive range of ecological conditions, generalizing the producer–scrounger framework to a wide diversity of taxa and resources. We show that resource ecology—defined by scarcity, depletion rate and monopolizability—determines patterns of individual differences in social information use. These differences suggest coevolutionary processes linking dominance systems and social information use, with implications for the evolutionary demography of populations. PMID:26888031

  20. Information use and resource competition: an integrative framework.

    PubMed

    Lee, Alexander E G; Ounsley, James P; Coulson, Tim; Rowcliffe, J Marcus; Cowlishaw, Guy

    2016-02-24

    Organisms may reduce uncertainty regarding how best to exploit their environment by collecting information about resource distribution. We develop a model to demonstrate how competition can facilitate or constrain an individual's ability to use information when acquiring resources. As resource distribution underpins both selection on information use and the strength and nature of competition between individuals, we demonstrate interdependencies between the two that should be common in nature. Individuals in our model can search for resources either personally or by using social information. We explore selection on social information use across a comprehensive range of ecological conditions, generalizing the producer-scrounger framework to a wide diversity of taxa and resources. We show that resource ecology--defined by scarcity, depletion rate and monopolizability--determines patterns of individual differences in social information use. These differences suggest coevolutionary processes linking dominance systems and social information use, with implications for the evolutionary demography of populations.