Negative Cooperativity in the EGF Receptor

PubMed Central

Pike, Linda J.

2012-01-01

Scatchard analyses of the binding of EGF to its receptor yield concave up Scatchard plots, indicative of some type of heterogenity in ligand binding affinity. This was typically interpreted as being due to the presence of two independent binding site–one of high affinity representing ≤10% of the receptor population and one of low affinity making up the bulk of the receptors. However, the concept of two independent binding sites is difficult to reconcile with the X-ray structures of the dimerized EGF receptor that show symmetric binding of the two ligands. A new approach to the analysis of 125I-EGF binding data combined with the structure of the singly-occupied Drosophila EGF receptor have now shown that this heterogeneity is due to the presence of negative cooperativity in the EGF receptor. Concerns that negative cooperativity precludes ligand-induced dimerization of the EGF receptor confuse the concepts of linkage cooperativity. Linkage refers to the effect of ligand on the assembly of dimers while cooperativity refers to the effect of ligand binding to one subunit on ligand binding to the other subunit within a preassembled dimer. Binding of EGF to its receptor is positively linked with dimer assembly but shows negative cooperativity within the dimer. PMID:22260659

Missing Fragments: Detecting Cooperative Binding in Fragment-Based Drug Design

PubMed Central

2012-01-01

The aim of fragment-based drug design (FBDD) is to identify molecular fragments that bind to alternate subsites within a given binding pocket leading to cooperative binding when linked. In this study, the binding of fragments to human phenylethanolamine N-methyltransferase is used to illustrate how (a) current protocols may fail to detect fragments that bind cooperatively, (b) theoretical approaches can be used to validate potential hits, and (c) apparent false positives obtained when screening against cocktails of fragments may in fact indicate promising leads. PMID:24900472

Measuring Positive Cooperativity Using the Direct ESI-MS Assay. Cholera Toxin B Subunit Homopentamer Binding to GM1 Pentasaccharide

NASA Astrophysics Data System (ADS)

Lin, Hong; Kitova, Elena N.; Klassen, John S.

2014-01-01

Direct electrospray ionization mass spectrometry (ESI-MS) assay was used to investigate the stepwise binding of the GM1 pentasaccharide β- D-Gal p-(1→3)-β-D-Gal pNAc-(1→4)[α-D-Neu5Ac-(2→3)]-β- D-Gal p-(1→4)-β-D-Glc p (GM1os) to the cholera toxin B subunit homopentamer (CTB5) and to establish conclusively whether GM1os binding is cooperative. Apparent association constants were measured for the stepwise addition of one to five GM1os to CTB5 at pH 6.9 and 22 °C. The intrinsic association constant, which was established from the apparent association constant for the addition of a single GM1os to CTB5, was found to be (3.2 ± 0.2) × 106 M-1. This is in reasonable agreement with the reported value of (6.4 ± 0.3) × 106 M-1, which was measured at pH 7.4 and 25 °C using isothermal titration calorimetry (ITC). Analysis of the apparent association constants provides direct and unambiguous evidence that GM1os binding exhibits small positive cooperativity. Binding was found to be sensitive to the number of ligand-bound nearest neighbor subunits, with the affinities enhanced by a factor of 1.7 and 2.9 when binding occurs next to one or two ligand-bound subunits, respectively. These findings, which provide quantitative support for the binding model proposed by Homans and coworkers [14], highlight the unique strengths of the direct ESI-MS assay for measuring cooperative ligand binding.

Cooperation for a competitive position: The impact of hospital cooperation behavior on organizational performance.

PubMed

Büchner, Vera Antonia; Hinz, Vera; Schreyögg, Jonas

2015-01-01

Several public policy initiatives, particularly those involving managed care, aim to enhance cooperation between partners in the health care sector because it is expected that such cooperation will reduce costs and generate additional revenue. However, empirical evidence regarding the effects of cooperation on hospital performance is scarce, particularly with respect to creating a comprehensive measure of cooperation behavior. The aim of this study is to investigate the impact of hospital cooperation behavior on organizational performance. We differentiate between horizontal and vertical cooperation using two alternative measures-cooperation depth and cooperation breadth-and include the interaction effects between both cooperation directions. Data are derived from a survey of German hospitals and combined with objective performance information from annual financial statements. Generalized linear regression models are used. The study findings provide insight into the nature of hospitals' cooperation behavior. In particular, we show that there are negative synergies between horizontal administrative cooperation behavior and vertical cooperation behavior. Whereas the depth and breadth of horizontal administrative cooperation positively affect financial performance (when there is no vertical cooperation), vertical cooperation positively affects financial performance (when there is no horizontal administrative cooperation) only when cooperation is broad (rather than deep). Horizontal cooperation is generally more effective than vertical cooperation at improving financial performance. Hospital managers should consider the negative interaction effect when making decisions about whether to recommend a cooperative relationship in a horizontal or vertical direction. In addition, managers should be aware of the limited financial benefit of cooperation behavior.

Cooperative context is a determinant of the social influence on outcome evaluation: An electrophysiological study.

PubMed

Kimura, Kenta; Katayama, Jun'ichi

2016-02-01

The present study examined whether or not a cooperative context is a determinant of the social influence on the evaluation of two action outcomes: a monetary outcome and a conflict of opinion with other group members. In the present study, three-person groups were randomly assigned to be either a cooperative or individual group and asked to perform a gambling task. The monetary outcomes in the cooperative group were interrelated among group members, whereas those in the individual group did not influence each other. The present results showed that monetary outcomes elicited feedback-related negativity (FRN) and a conflict of opinion with other group members elicited FRN-like negativity, which reflect an evaluation of the motivational significance of action outcomes. The FRN elicited by monetary outcomes was reduced when participants shared decisions with other group members only in the cooperative group, indicating that the cooperative context reduced the motivational significance of monetary outcomes through the diffusion of responsibility. The FRN-like negativity elicited by a conflict of opinion showed a different pattern between the cooperative and individual groups, indicating that the cooperative context can influence the evaluation of a conflict of opinion, possibly via the modulation of group cohesiveness or conflict processing. The present results suggest that a cooperative context, rather than the social setting, is a determinant of the social influence on outcome evaluation. Copyright © 2015 Elsevier B.V. All rights reserved.

A new consequence of Simpson's paradox: stable cooperation in one-shot prisoner's dilemma from populations of individualistic learners.

PubMed

Chater, Nick; Vlaev, Ivo; Grinberg, Maurice

2008-08-01

Theories of choice in economics typically assume that interacting agents act individualistically and maximize their own utility. Specifically, game theory proposes that rational players should defect in one-shot prisoners' dilemmas (PD). Defection also appears to be the inevitable outcome for agents who learn by reinforcement of past choices, because whatever the other player does, defection leads to greater reinforcement on each trial. In a computer simulation and 4 experiments, the authors show that, apparently paradoxically, when players' choices are correlated by an exogenous factor (here, the cooperativeness of the specific PD chosen), people obtain greater average reinforcement for cooperating, which can sustain cooperation. This effect arises from a well-known statistical paradox, Simpson's paradox. The authors speculate that this effect may be relevant to aspects of real-world human cooperative behavior.

Thailand: Background and U.S. Relations

DTIC Science & Technology

2009-06-08

relations will fare as Bangkok seeks political stability . With Thai nationalism apparently on the rise, some analysts see a risk of drift in the U.S.-Thai relationship, although no major shift in overall cooperation.

Thailand: Background and U.S. Relations

DTIC Science & Technology

2008-12-19

relations will fare as Bangkok seeks political stability . With Thai nationalism apparently on the rise, some analysts see a risk of drift in the U.S.-Thai relationship, although no major shift in overall cooperation.

Human uniqueness-self-interest and social cooperation.

PubMed

Okada, Daijiro; Bingham, Paul M

2008-07-21

Humans are unique among all species of terrestrial history in both ecological dominance and individual properties. Many, or perhaps all, of the unique elements of this nonpareil status can be plausibly interpreted as evolutionary and strategic elements and consequences of the unprecedented intensity and scale of our social cooperation. Convincing explanation of this unique human social adaptation remains a central, unmet challenge to the scientific enterprise. We develop a hypothesis for the ancestral origin of expanded cooperative social behavior. Specifically, we present a game theoretic analysis demonstrating that a specific pattern of expanded social cooperation between conspecific individuals with conflicts of interest (including non-kin) can be strategically viable, but only in animals that possess a highly unusual capacity for conspecific violence (credible threat) having very specific properties that dramatically reduce the costs of coercive violence. The resulting reduced costs allow preemptive or compensated coercion to be an instantaneously self-interested behavior under diverse circumstances rather than in rare, idiosyncratic circumstances as in actors (animals) who do not have access to inexpensive coercive threat. Humans are apparently unique among terrestrial organisms in having evolved conspecific coercive capabilities that fulfill these stringent requirements. Thus, our results support the proposal that access to a novel capacity for projection of coercive threat might represent the essential initiating event for the evolution of a human-like pattern of social cooperation and the subsequent evolution of the diverse features of human uniqueness. Empirical evidence indicates that these constraints were, in fact, met only in our evolutionary lineage. The logic for the emergence of uniquely human cooperation suggested by our analysis apparently accounts simply for the human fossil record.

Understanding marital conflict 7 years later from prenatal representations of marriage.

PubMed

Curran, Melissa; Ogolsky, Brian; Hazen, Nancy; Bosch, Leslie

2011-06-01

We examine how representations of marriage, assessed prenatally, predict different types of marital conflict (cooperation, avoidance/capitulation, stonewalling, and child involvement in parental conflict) at 7 years postpartum (N=132 individuals). We assessed representations of marriage prenatally by interviewing spouses about their own parents' marriage, and then rated the content and insightfulness of their memories. Results show that marital representations characterized by higher insight predict higher cooperation and lower child involvement in parental conflict, whereas content of marital representations was not a significant predictor of marital conflict. Further, individuals who remember negative memories from their parents' marriage with high insight were lowest on child involvement in parental conflict, whereas those who remember negative memories with low insight were highest on child involvement in parental conflict. Finally, women who remember negative content with high insight report the highest cooperation, whereas women who remember negative content with low insight report the lowest cooperation. For men, however, marital representations were less effective in predicting later cooperation. We conclude that marital representations, even when assessed prenatally, influence certain types of marital conflict 7 years later. Using such findings, therapists could help spouses gain insight into how the memories of their parents' marriage relate to the use of specific conflict strategies in their marriage. 2011 © FPI, Inc.

Asparagine, valine, and threonine in the third extracellular loop of muscarinic receptor have essential roles in the positive cooperativity of strychnine-like allosteric modulators.

PubMed

Jakubík, J; Krejcí, A; Dolezal, V

2005-05-01

We have investigated allosteric interactions of four closely related strychnine-like substances: Wieland-Gumlich aldehyde (WGA), propargyl Wieland-Gumlich aldehyde, strychnine, and brucine with N-methylscopolamine (NMS) on M(3) subtype of muscarinic receptor genetically modified in the second or the third extracellular loop to corresponding loops of M(2) subtype (M(3)o2 and M(3)o3 chimera). The M(3)o2 chimeric receptor The exhibited no change in either affinity of strychnine, brucine, and WGA or in cooperativity of brucine or WGA, whereas both parameters for propargyl-WGA changed. In contrast, there was a change in affinity of all tested modulators (except for brucine) and in their cooperativity in the M(3)o3 chimera. Directions of affinity changes in both chimeras were always toward values of the donor M(2) subtype, but changes in cooperativity were variable. Compared with the native M(3) receptor, strychnine displayed a slight increase in positive cooperativity and propargyl-WGA a robust decrease in negative cooperativity at M(3)o2 chimera. Similar changes were found in the M(3)o3 chimera. Interestingly, cooperativity of brucine and WGA at the M(3)o3 chimera changed from negative to positive. This is the first evidence of constitution of positive cooperativity of WGA by switching sequences of two parental receptors, both exhibiting negative cooperativity. Gradual replacement of individual amino acids revealed that only three residues (NVT of the o3 loop of the M(2) receptor) are involved in this effect. Data suggest that these amino acids are essential for propagation of a conformation change resulting in positive cooperativity induced by these modulators.

Avian cooperative breeding: Old hypotheses and new directions.

PubMed

Heinsohn, R G; Cockburn, A; Mulder, R A

1990-12-01

In cooperatively breeding birds, individuals that appear capable of reproducing on their own may instead assist others with their breeding efforts. Research into avian cooperative breeding has attempted to reconcile the apparent altruism of this behaviour with maximization of inclusive fitness. Most explanations of cooperative breeding have suggested that philopatry is enforced by ecological constraints, such as a shortage of resources critical to breeding. Non-dispersers may then benefit both directly and indirectly from contributing at the nest. Recent research has shown that such benefits may be sufficient to promote philopatry, without the need for ecological constraints, and emphasizes that consideration of both costs and benefits of philopatry is essential for a comprehensive approach to the problem. The growing body of data from long-term studies of different species should combine with an improved phylogenetic perspective on cooperative breeding, to provide a useful base for future comparative analyses and experimentation. Copyright © 1990. Published by Elsevier Ltd.

Judgments about Cooperators and Freeriders on a Shuar Work Team: An Evolutionary Psychological Perspective

ERIC Educational Resources Information Center

Price, Michael E.

2006-01-01

Evolutionary biological theories of group cooperation predict that (1) group members will tend to judge cooperative co-members favorably, and freeriding co-members negatively and (2) members who themselves cooperate more frequently will be especially likely to make these social judgments. An experiment tested these predictions among Shuar…

A Hypothesis of the Co-evolution of Cooperation and Responses to Inequity

PubMed Central

Brosnan, Sarah F.

2011-01-01

Recent evidence demonstrates that humans are not the only species to respond negatively to inequitable outcomes which are to their disadvantage. Several species respond negatively if they subsequently receive a less good reward than a social partner for completing the same task. While these studies suggest that the negative response to inequity is not a uniquely human behavior, they do not provide a functional explanation for the emergence of these responses due to similar characteristics among these species. However, emerging data support the hypothesis that an aversion to inequity is a mechanism to promote successful long-term cooperative relationships amongst non-kin. In this paper, I discuss several converging lines of evidence which illustrate the need to further evaluate this relationship. First, cooperation can survive modest inequity; in explicitly cooperative interactions, individuals are willing to continue to cooperate despite inequitable outcomes as long as the partner's overall behavior is equitable. Second, the context of inequity affects reactions to it in ways which support the idea that joint efforts lead to an expectation of joint payoffs. Finally, comparative studies indicate a link between the degree and extent of cooperation between unrelated individuals in a species and that species’ response to inequitable outcomes. This latter line of evidence indicates that this behavior evolved in conjunction with cooperation and may represent an adaptation to increase the payoffs associated with cooperative interactions. Together these data inform a testable working hypothesis for understanding decision-making in the context of inequity and provide a new, comparative framework for evaluating decision-making behavior. PMID:21519380

Learn good from bad: Effects of good and bad neighbors in spatial prisoners' dilemma games

NASA Astrophysics Data System (ADS)

Lu, Peng

2015-10-01

Cooperation is vital for the human society and this study focuses on how to promote cooperation. In our stratification model, there exist three classes: two minorities are elites who are prone to cooperate and scoundrels who are born to defect; one majority is the class of common people. Agents of these three classes interact with each other on a square lattice. Commons' cooperation and its factors are investigated. Contradicting our common sense, it indicates that elites play a negative role while scoundrels play a positive one in promoting commons' cooperation. Besides, effects of good and bad neighbors vary with temptation. When the temptation is smaller the positive effect is able to overcome the negative effect, but the later prevails when the temptation is larger. It concludes that common people are more prone to cooperate in harsh environment with bad neighbors, and a better environment with good neighbors merely leads to laziness and free riding of commons.

Promoting cooperation and trust in "noisy" situations: the power of generosity.

PubMed

Klapwijk, Anthon; Van Lange, Paul A M

2009-01-01

The authors present an interdependence theoretical framework and advance the argument that generosity serves the important purpose of communicating trust, which is assumed to be of utmost importance to coping with incidents of negative noise (i.e., when the other every now and then behaves less cooperatively than intended). Using a new social dilemma task (the parcel delivery paradigm), it was hypothesized that incidents of negative noise would exert detrimental effects on trust and trust-related judgments and experiences, as well as cooperation, and that relative to tit for tat and self-regarding strategies (stingy or unconditionally cooperative strategies), other-regarding strategies (i.e., unconditional cooperation and generosity) would be more effective at reducing such as detrimental effects. Results from 2 studies provided strong support for these hypotheses, suggesting that the power of generosity is underestimated in the extant literature, especially in its ability to maintain or build trust, which is essential for coping with noise.

Separating conditional and unconditional cooperation in a sequential Prisoner’s Dilemma game

PubMed Central

Mieth, Laura; Buchner, Axel

2017-01-01

Most theories of social exchange distinguish between two different types of cooperation, depending on whether or not cooperation occurs conditional upon the partner’s previous behaviors. Here, we used a multinomial processing tree model to distinguish between positive and negative reciprocity and cooperation bias in a sequential Prisoner’s Dilemma game. In Experiments 1 and 2, the facial expressions of the partners were varied to manipulate cooperation bias. In Experiment 3, an extinction instruction was used to manipulate reciprocity. The results confirm that people show a stronger cooperation bias when interacting with smiling compared to angry-looking partners, supporting the notion that a smiling facial expression in comparison to an angry facial expression helps to construe a situation as cooperative rather than competitive. Reciprocity was enhanced for appearance-incongruent behaviors, but only when participants were encouraged to form expectations about the partners’ future behaviors. Negative reciprocity was not stronger than positive reciprocity, regardless of whether expectations were manipulated or not. Experiment 3 suggests that people are able to ignore previous episodes of cheating as well as previous episodes of cooperation if these turn out to be irrelevant for predicting a partner’s future behavior. The results provide important insights into the mechanisms of social cooperation. PMID:29121671

Andreev reflections and the quantum physics of black holes

NASA Astrophysics Data System (ADS)

Manikandan, Sreenath K.; Jordan, Andrew N.

2017-12-01

We establish an analogy between superconductor-metal interfaces and the quantum physics of a black hole, using the proximity effect. We show that the metal-superconductor interface can be thought of as an event horizon and Andreev reflection from the interface is analogous to the Hawking radiation in black holes. We describe quantum information transfer in Andreev reflection with a final state projection model similar to the Horowitz-Maldacena model for black hole evaporation. We also propose the Andreev reflection analogue of Hayden and Preskill's description of a black hole final state, where the black hole is described as an information mirror. The analogy between crossed Andreev reflections and Einstein-Rosen bridges is discussed: our proposal gives a precise mechanism for the apparent loss of quantum information in a black hole by the process of nonlocal Andreev reflection, transferring the quantum information through a wormhole and into another universe. Given these established connections, we conjecture that the final quantum state of a black hole is exactly the same as the ground state wave function of the superconductor/superfluid in the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity; in particular, the infalling matter and the infalling Hawking quanta, described in the Horowitz-Maldacena model, forms a Cooper pairlike singlet state inside the black hole. A black hole evaporating and shrinking in size can be thought of as the analogue of Andreev reflection by a hole where the superconductor loses a Cooper pair. Our model does not suffer from the black hole information problem since Andreev reflection is unitary. We also relate the thermodynamic properties of a black hole to that of a superconductor, and propose an experiment which can demonstrate the negative specific heat feature of black holes in a growing/evaporating condensate.

Apparent Negative Reflection with the Gradient Acoustic Metasurface by Integrating Supercell Periodicity into the Generalized Law of Reflection.

PubMed

Liu, Bingyi; Zhao, Wenyu; Jiang, Yongyuan

2016-12-05

As the two dimensional version of the functional wavefront manipulation metamaterial, metasurface has become a research hot spot for engineering the wavefront at will with a subwavelength thickness. The wave scattered by the gradient metasurface, which is composed by the periodic supercells, is governed by the generalized Snell's law. However, the critical angle that derived from the generalized Snell's law circles the domain of the incident angles that allow the occurrence of the anomalous reflection and refraction, and no free space scattering waves could exist when the incident angle is beyond the critical angle. Here we theoretically demonstrate that apparent negative reflection can be realized by a gradient acoustic metasurface when the incident angle is beyond the critical angle. The underlying mechanism of the apparent negative reflection is understood as the higher order diffraction arising from the interaction between the local phase modulation and the non-local effects introduced by the supercell periodicity. The apparent negative reflection phenomena has been perfectly verified by the calculated scattered acoustic waves of the reflected gradient acoustic metasurface. This work may provide new freedom in designing functional acoustic signal modulation devices, such as acoustic isolator and acoustic illusion device.

Cooperative Games and Children's Positive Behaviors.

ERIC Educational Resources Information Center

Finlinson, Abbie Reynolds; Austin, Ann M. Berghout; Pfister, Roxane

2000-01-01

Examined impact of cooperative and competitive games on 4-year-olds' behavior over 6 weeks. Found that more positive behaviors were observed during cooperative games than competitive games, and more negative behaviors were observed during competitive games, but only during the first week of competitive games. Found that teachers' warmth and…

Functional brain connectivity when cooperation fails.

PubMed

Balconi, Michela; Vanutelli, Maria Elide; Gatti, Laura

2018-06-01

Functional connectivity during cooperative actions is an important topic in social neuroscience that has yet to be answered. Here, we examined the effects of administration of (fictitious) negative social feedback in relation to cooperative capabilities. Cognitive performance and neural activation underlying the execution of joint actions was recorded with functional near-infrared spectroscopy (fNIRS) on prefrontal regions during a task where pairs of participants received negative feedback after their joint action. Performance (error rates (ERs) and response times (RTs)) and intra- and inter-brain connectivity indices were computed, along with the ConIndex (inter-brain/intra-brain connectivity). Finally, correlational measures were considered to assess the relation between these different measures. Results showed that the negative feedback was able to modulate participants' responses for both behavioral and neural components. Cognitive performance was decreased after the feedback. Moreover, decreased inter-brain connectivity and increased intra-brain connectivity was induced by the feedback, whereas the cooperative task pre-feedback condition was able to increase the brain-to-brain coupling, mainly localized within the dorsolateral prefrontal cortex (DLPFC). Finally, the presence of significant correlations between RTs and inter-brain connectivity revealed that ineffective joint action produces the worst cognitive performance and a more 'individual strategy' for brain activity, limiting the inter-brain connectivity. The present study provides a significant contribution to the identification of patterns of intra- and inter-brain functional connectivity when negative social reinforcement is provided in relation to cooperative actions. Copyright © 2018 Elsevier Inc. All rights reserved.

Asymmetric interaction and indeterminate fitness correlation between cooperative partners in the fig–fig wasp mutualism

PubMed Central

Wang, Rui-Wu; Sun, Bao-Fa; Zheng, Qi; Shi, Lei; Zhu, Lixing

2011-01-01

Empirical observations have shown that cooperative partners can compete for common resources, but what factors determine whether partners cooperate or compete remain unclear. Using the reciprocal fig–fig wasp mutualism, we show that nonlinear amplification of interference competition between fig wasps—which limits the fig wasps' ability to use a common resource (i.e. female flowers)—keeps the common resource unsaturated, making cooperation locally stable. When interference competition was manually prevented, the fitness correlation between figs and fig wasps went from positive to negative. This indicates that genetic relatedness or reciprocal exchange between cooperative players, which could create spatial heterogeneity or self-restraint, was not sufficient to maintain stable cooperation. Moreover, our analysis of field-collected data shows that the fitness correlation between cooperative partners varies stochastically, and that the mainly positive fitness correlation observed during the warm season shifts to a negative correlation during the cold season owing to an increase in the initial oviposition efficiency of each fig wasp. This implies that the discriminative sanction of less-cooperative wasps (i.e. by decreasing the egg deposition efficiency per fig wasp) but reward to cooperative wasps by fig, a control of the initial value, will facilitate a stable mutualism. Our finding that asymmetric interaction leading to an indeterminate fitness interaction between symbiont (i.e. cooperative actors) and host (i.e. recipient) has the potential to explain why conflict has been empirically observed in both well-documented intraspecific and interspecific cooperation systems. PMID:21490005

Cheating and punishment in cooperative animal societies

PubMed Central

Riehl, Christina; Frederickson, Megan E.

2016-01-01

Cheaters—genotypes that gain a selective advantage by taking the benefits of the social contributions of others while avoiding the costs of cooperating—are thought to pose a major threat to the evolutionary stability of cooperative societies. In order for cheaters to undermine cooperation, cheating must be an adaptive strategy: cheaters must have higher fitness than cooperators, and their behaviour must reduce the fitness of their cooperative partners. It is frequently suggested that cheating is not adaptive because cooperators have evolved mechanisms to punish these behaviours, thereby reducing the fitness of selfish individuals. However, a simpler hypothesis is that such societies arise precisely because cooperative strategies have been favoured over selfish ones—hence, behaviours that have been interpreted as ‘cheating’ may not actually result in increased fitness, even when they go unpunished. Here, we review the empirical evidence for cheating behaviours in animal societies, including cooperatively breeding vertebrates and social insects, and we ask whether such behaviours are primarily limited by punishment. Our review suggests that both cheating and punishment are probably rarer than often supposed. Uncooperative individuals typically have lower, not higher, fitness than cooperators; and when evidence suggests that cheating may be adaptive, it is often limited by frequency-dependent selection rather than by punishment. When apparently punitive behaviours do occur, it remains an open question whether they evolved in order to limit cheating, or whether they arose before the evolution of cooperation. PMID:26729930

Working dogs cooperate among one another by generalised reciprocity.

PubMed

Gfrerer, Nastassja; Taborsky, Michael

2017-03-06

Cooperation by generalised reciprocity implies that individuals apply the decision rule "help anyone if helped by someone". This mechanism has been shown to generate evolutionarily stable levels of cooperation, but as yet it is unclear how widely this cooperation mechanism is applied among animals. Dogs (Canis familiaris) are highly social animals with considerable cognitive potential and the ability to differentiate between individual social partners. But although dogs can solve complex problems, they may use simple rules for behavioural decisions. Here we show that dogs trained in an instrumental cooperative task to provide food to a social partner help conspecifics more often after receiving help from a dog before. Remarkably, in so doing they show no distinction between partners that had helped them before and completely unfamiliar conspecifics. Apparently, dogs use the simple decision rule characterizing generalised reciprocity, although they are probably capable of using the more complex decision rule of direct reciprocity: "help someone who has helped you". However, generalized reciprocity involves lower information processing costs and is therefore a cheaper cooperation strategy. Our results imply that generalised reciprocity might be applied more commonly than direct reciprocity also in other mutually cooperating animals.

Working dogs cooperate among one another by generalised reciprocity

PubMed Central

Gfrerer, Nastassja; Taborsky, Michael

2017-01-01

Cooperation by generalised reciprocity implies that individuals apply the decision rule “help anyone if helped by someone”. This mechanism has been shown to generate evolutionarily stable levels of cooperation, but as yet it is unclear how widely this cooperation mechanism is applied among animals. Dogs (Canis familiaris) are highly social animals with considerable cognitive potential and the ability to differentiate between individual social partners. But although dogs can solve complex problems, they may use simple rules for behavioural decisions. Here we show that dogs trained in an instrumental cooperative task to provide food to a social partner help conspecifics more often after receiving help from a dog before. Remarkably, in so doing they show no distinction between partners that had helped them before and completely unfamiliar conspecifics. Apparently, dogs use the simple decision rule characterizing generalised reciprocity, although they are probably capable of using the more complex decision rule of direct reciprocity: “help someone who has helped you”. However, generalized reciprocity involves lower information processing costs and is therefore a cheaper cooperation strategy. Our results imply that generalised reciprocity might be applied more commonly than direct reciprocity also in other mutually cooperating animals. PMID:28262722

Synthesis of (nor)tropeine (di)esters and allosteric modulation of glycine receptor binding.

PubMed

Maksay, Gábor; Nemes, Péter; Vincze, Zoltán; Bíró, Timea

2008-02-15

(Hetero)aromatic mono- and diesters of tropine and nortropine were prepared. Modulation of [3H]strychnine binding to glycine receptors of rat spinal cord was examined with a ternary allosteric model. The esters displaced [3H]strychnine binding with nano- or micromolar potencies and strong negative cooperativity. Coplanarity and distance of the ester moieties of diesters affected the binding affinity being nanomolar for isophthaloyl-bistropane and nortropeines. Nortropisetron had the highest affinity (K(A) approximately 10 nM). Two esters displayed negative cooperativity with glycine in displacement, while three esters of low-affinity and nortropisetron exerted positive cooperativity with glycine.

Cooperation beyond the dyad: on simple models and a complex society

PubMed Central

Connor, Richard C.

2010-01-01

Players in Axelrod and Hamilton's model of cooperation were not only in a Prisoner's Dilemma, but by definition, they were also trapped in a dyad. But animals are rarely so restricted and even the option to interact with third parties allows individuals to escape from the Prisoner's Dilemma into a much more interesting and varied world of cooperation, from the apparently rare ‘parcelling’ to the widespread phenomenon of market effects. Our understanding of by-product mutualism, pseudo-reciprocity and the snowdrift game is also enriched by thinking ‘beyond the dyad’. The concepts of by-product mutualism and pseudo-reciprocity force us to think again about our basic definitions of cooperative behaviour (behaviour by a single individual) and cooperation (the outcome of an interaction between two or more individuals). Reciprocity is surprisingly rare outside of humans, even among large-brained ‘intelligent’ birds and mammals. Are humans unique in having extensive cooperative interactions among non-kin and an integrated cognitive system for mediating reciprocity? Perhaps, but our best chance for finding a similar phenomenon may be in delphinids, which also live in large societies with extensive cooperative interactions among non-relatives. A system of nested male alliances in bottlenose dolphins illustrates the potential and difficulties of finding a complex system of cooperation close to our own. PMID:20679112

Redox interactions in cytochrome c oxidase: from the "neoclassical" toward "modern" models.

PubMed Central

Hendler, R W; Westerhoff, H V

1992-01-01

Because of recent experimental data on the redox characteristics of cytochrome c oxidase and renewed interest in the role of cooperativity in energy coupling, the question of redox cooperativity in cytochrome c oxidase is reexamined. Extensive redox cooperativity between more than two redox centers, some of which are spectrally invisible, may be expected for this electron transfer coupled proton pump. Such cooperativity, however, cannot be revealed by the traditional potentiometric experiments based on a difference in absorbance between two wavelengths. Multiwavelength analyses utilizing singular value decomposition and second derivatives of absorbance vs. wavelength have revealed a stronger cooperativity than consistent with the "neoclassical" model, which allowed only for weak negative cooperativity between two equipotential one-electron centers. A thermodynamic analysis of redox cooperativity is developed, which includes the possibilities of strong cooperative redox interactions, the involvement of invisible redox centers, conformational changes, and monomer/dimer equilibrations. The experimental observation of an oxidation of one of the cytochromes (a3) with a decrease in applied redox potential is shown to require both strong negative cooperativity and the participation of more than two one-electron centers. A number of "modern" models are developed using the analytical approaches described in this paper. By testing with experimental data, some of these models are falsified, whereas some are retained with suggestions for further testing. PMID:1336989

DNA typing by microbead arrays and PCR-SSP: apparent false-negative or -positive hybridization or amplification signals disclose new HLA-B and -DRB1 alleles.

PubMed

Rahal, M; Kervaire, B; Villard, J; Tiercy, J-M

2008-03-01

Human leukocyte antigen (HLA) typing by polymerase chain reaction-sequence-specific oligonucleotide (PCR-SSO) hybridization on solid phase (microbead assay) or polymerase chain reaction-sequence-specific primers (PCR-SSP) requires interpretation softwares to detect all possible allele combinations. These programs propose allele calls by taking into account false-positive or false-negative signal(s). The laboratory has the option to validate typing results in the presence of strongly cross-reacting or apparent false-negative signals. Alternatively, these seemingly aberrant signals may disclose novel variants. We report here four new HLA-B (B*5620 and B*5716) and HLA-DRB1 alleles (DRB1*110107 and DRB1*1474) that were detected by apparent false-negative or -positive hybridization or amplification patterns, and ultimately resolved by sequencing. To avoid allele misassignments, a comprehensive evaluation of acquired data as documented in a quality assurance system is therefore required to confirm unambiguous typing interpretation.

How the workload impacts on cognitive cooperation: A pilot study.

PubMed

Sciaraffa, Nicolina; Borghini, Gianluca; Arico, Pietro; Di Flumeri, Gianluca; Toppi, Jlenia; Colosimo, Alfredo; Bezerianos, Anastatios; Thakor, Nitish V; Babiloni, Fabio

2017-07-01

Cooperation degradation can be seen as one of the main causes of human errors. Poor cooperation could arise from aberrant mental processes, such as mental overload, that negatively affect the user's performance. Using different levels of difficulty in a cooperative task, we combined behavioural, subjective and neurophysiological data with the aim to i) quantify the mental workload under which the crew was operating, ii) evaluate the degree of their cooperation, and iii) assess the impact of the workload demands on the cooperation levels. The combination of such data showed that high workload demand impacted significantly on the performance, workload perception, and degree of cooperation.

Exploring the impact of positive and negative emotions on cooperative behaviour in a Prisoner’s Dilemma Game

PubMed Central

Thompson, Sam

2013-01-01

Objective. To explore the influences of discrete positive and negative emotions on cooperation in the context of a social dilemma game. Design. Two controlled studies were undertaken. In Study 1, 69 participants were randomly assigned to an essay emotion manipulation task designed to induce either guilt, joy or no strong emotion. In Study 2, 95 participants were randomly assigned to one of the same three tasks, and the impact of emotional condition on cooperation was explored using a repeated Prisoner’s Dilemma Game. Results. Study 1 established that the manipulation task was successful in inducing the specified emotions. The analysis from Study 2 revealed no significant main effects for emotions, in contrast to previous research. However, there was a significant effect for participants’ pre-existing tendency to cooperate (social value orientation; SVO). Conclusion. Methodological explanations for the result are explored, including the possible impact of trial-and-error strategies, different cooperation games and endogenous vs exogenous emotions. PMID:24432196

Exploring the impact of positive and negative emotions on cooperative behaviour in a Prisoner's Dilemma Game.

PubMed

Kjell, Oscar N E; Thompson, Sam

2013-12-19

Objective. To explore the influences of discrete positive and negative emotions on cooperation in the context of a social dilemma game. Design. Two controlled studies were undertaken. In Study 1, 69 participants were randomly assigned to an essay emotion manipulation task designed to induce either guilt, joy or no strong emotion. In Study 2, 95 participants were randomly assigned to one of the same three tasks, and the impact of emotional condition on cooperation was explored using a repeated Prisoner's Dilemma Game. Results. Study 1 established that the manipulation task was successful in inducing the specified emotions. The analysis from Study 2 revealed no significant main effects for emotions, in contrast to previous research. However, there was a significant effect for participants' pre-existing tendency to cooperate (social value orientation; SVO). Conclusion. Methodological explanations for the result are explored, including the possible impact of trial-and-error strategies, different cooperation games and endogenous vs exogenous emotions.

Apparent Negative Reflection with the Gradient Acoustic Metasurface by Integrating Supercell Periodicity into the Generalized Law of Reflection

PubMed Central

Liu, Bingyi; Zhao, Wenyu; Jiang, Yongyuan

2016-01-01

As the two dimensional version of the functional wavefront manipulation metamaterial, metasurface has become a research hot spot for engineering the wavefront at will with a subwavelength thickness. The wave scattered by the gradient metasurface, which is composed by the periodic supercells, is governed by the generalized Snell’s law. However, the critical angle that derived from the generalized Snell’s law circles the domain of the incident angles that allow the occurrence of the anomalous reflection and refraction, and no free space scattering waves could exist when the incident angle is beyond the critical angle. Here we theoretically demonstrate that apparent negative reflection can be realized by a gradient acoustic metasurface when the incident angle is beyond the critical angle. The underlying mechanism of the apparent negative reflection is understood as the higher order diffraction arising from the interaction between the local phase modulation and the non-local effects introduced by the supercell periodicity. The apparent negative reflection phenomena has been perfectly verified by the calculated scattered acoustic waves of the reflected gradient acoustic metasurface. This work may provide new freedom in designing functional acoustic signal modulation devices, such as acoustic isolator and acoustic illusion device. PMID:27917909

Event-related potentials in response to cheating and cooperation in a social dilemma game.

PubMed

Bell, Raoul; Sasse, Julia; Möller, Malte; Czernochowski, Daniela; Mayr, Susanne; Buchner, Axel

2016-02-01

A sequential prisoner's dilemma game was combined with psychophysiological measures to examine the cognitive underpinnings of reciprocal exchange. Participants played four rounds of the game with partners who either cooperated or cheated. In a control condition, the partners' faces were shown, but no interaction took place. The partners' behaviors were consistent in the first three rounds of the game, but in the last round some of the partners unexpectedly changed strategies. In the first round of the game, the feedback about a partner's decision elicited a feedback P300, which was more pronounced for cooperation and cheating in comparison to the control condition, but did not vary as a function of feedback valence. In the last round, both the feedback negativity and the feedback P300 were sensitive to expectancy violations. There was no consistent evidence for a negativity bias, that is, enhanced allocation of attention to feedback about another person's cheating in comparison to feedback about another person's cooperation. Instead, participants focused on both positive and negative information, and flexibly adjusted their processing biases to the diagnosticity of the information. This conclusion was corroborated by the ERP correlates of memory retrieval. Successful retrieval of a partner's reputation was associated with an anterior positivity between 400 and 600 ms after face onset. This anterior positivity was more pronounced for both cooperator and cheater faces in comparison to control faces. The results suggest that it is not the negativity of social information, but rather its motivational and behavioral relevance that determines its processing. © 2015 Society for Psychophysiological Research.

The virtues of gossip: reputational information sharing as prosocial behavior.

PubMed

Feinberg, Matthew; Willer, Robb; Stellar, Jennifer; Keltner, Dacher

2012-05-01

Reputation systems promote cooperation and deter antisocial behavior in groups. Little is known, however, about how and why people share reputational information. Here, we seek to establish the existence and dynamics of prosocial gossip, the sharing of negative evaluative information about a target in a way that protects others from antisocial or exploitative behavior. We present a model of prosocial gossip and the results of 4 studies testing the model's claims. Results of Studies 1 through 3 demonstrate that (a) individuals who observe an antisocial act experience negative affect and are compelled to share information about the antisocial actor with a potentially vulnerable person, (b) sharing such information reduces negative affect created by observing the antisocial behavior, and (c) individuals possessing more prosocial orientations are the most motivated to engage in such gossip, even at a personal cost, and exhibit the greatest reduction in negative affect as a result. Study 4 demonstrates that prosocial gossip can effectively deter selfishness and promote cooperation. Taken together these results highlight the roles of prosocial motivations and negative affective reactions to injustice in maintaining reputational information sharing in groups. We conclude by discussing implications for reputational theories of the maintenance of cooperation in human groups.

Education in the Gulf Monarchies: Retrospect and Prospect.

ERIC Educational Resources Information Center

Bahgat, Gawdat

1999-01-01

Examines three of the apparent deficiencies in the educational system in the six Gulf Cooperation Council member states: a mismatch between traditional and modern learning, an imbalance between indigenous and expatriate labor forces, and the gap between men and women. Concludes that a fundamental change in educational quality is needed. Contains…

Social diversity promotes the emergence of cooperation in public goods games.

PubMed

Santos, Francisco C; Santos, Marta D; Pacheco, Jorge M

2008-07-10

Humans often cooperate in public goods games and situations ranging from family issues to global warming. However, evolutionary game theory predicts that the temptation to forgo the public good mostly wins over collective cooperative action, and this is often also seen in economic experiments. Here we show how social diversity provides an escape from this apparent paradox. Up to now, individuals have been treated as equivalent in all respects, in sharp contrast with real-life situations, where diversity is ubiquitous. We introduce social diversity by means of heterogeneous graphs and show that cooperation is promoted by the diversity associated with the number and size of the public goods game in which each individual participates and with the individual contribution to each such game. When social ties follow a scale-free distribution, cooperation is enhanced whenever all individuals are expected to contribute a fixed amount irrespective of the plethora of public goods games in which they engage. Our results may help to explain the emergence of cooperation in the absence of mechanisms based on individual reputation and punishment. Combining social diversity with reputation and punishment will provide instrumental clues on the self-organization of social communities and their economical implications.

Symmetry warrants rational cooperation by co-action in Social Dilemmas.

PubMed

Sasidevan, V; Sinha, Sitabhra

2015-08-12

Is it rational for selfish individuals to cooperate? The conventional answer based on analysis of games such as the Prisoners Dilemma (PD) is that it is not, even though mutual cooperation results in a better outcome for all. This incompatibility between individual rationality and collective benefit lies at the heart of questions about the evolution of cooperation, as illustrated by PD and similar games. Here, we argue that this apparent incompatibility is due to an inconsistency in the standard Nash framework for analyzing non-cooperative games and propose a new paradigm, that of the co-action equilibrium. As in the Nash solution, agents know that others are just as rational as them and taking this into account lead them to realize that others will independently adopt the same strategy, in contrast to the idea of unilateral deviation central to Nash equilibrium thinking. Co-action equilibrium results in better collective outcomes for games representing social dilemmas, with relatively "nicer" strategies being chosen by rational selfish individuals. In particular, the dilemma of PD gets resolved within this framework, suggesting that cooperation can evolve in nature as the rational outcome even for selfish agents, without having to take recourse to additional mechanisms for promoting it.

Voluntary strategy suppresses the positive impact of preferential selection in prisoner’s dilemma

NASA Astrophysics Data System (ADS)

Sun, Lei; Lin, Pei-jie; Chen, Ya-shan

2014-11-01

Impact of aspiration is ubiquitous in social and biological disciplines. In this work, we try to explore the impact of such a trait on voluntary prisoners’ dilemma game via a selection parameter w. w=0 returns the traditional version of random selection. For positive w, the opponent of high payoff will be selected; while negative w means that the partner of low payoff will be chosen. We find that for positive w, cooperation will be greatly promoted in the interval of small b, at variance cooperation is inhibited with large b. For negative w, cooperation is fully restrained, irrespective of b value. It is found that the positive impact of preferential selection is suppressed by the voluntary strategy in prisoner’s dilemma. These observations can be supported by the spatial patterns. Our work may shed light on the emergence and persistence of cooperation with voluntary participation in social dilemma.

Prosocial Behavior and Subjective Insecurity in Violent Contexts: Field Experiments.

PubMed

Vélez, María Alejandra; Trujillo, Carlos Andres; Moros, Lina; Forero, Clemente

2016-01-01

Subjective insecurity is a key determinant of different forms of prosocial behavior. In Study 1, we used field experiments with farmers in Colombian villages exposed to different levels of violence to investigate how individual perceptions of insecurity affect cooperation, trust, reciprocity and altruism. To do so, we developed a cognitive-affective measure of subjective insecurity. We found that subjective insecurity has a negative effect on cooperation but influences trust and altruism positively. In Study 2, carried out three years after Study 1, we repeated the initial design with additional measures of victimization. Our goal was to relate subjective insecurity with actual victimization. The findings of Study 2 support the initial results, and are robust and consistent for cooperative behavior and trust when including victimization as a mediator. Different indicators of victimization are positively correlated with subjective insecurity and an aggregate index of victimization has a negative effect on cooperation but exerts a positive influence on trust.

Lactose binding to galectin-1 modulates structural dynamics, increases conformational entropy, and occurs with apparent negative cooperativity.

PubMed

Nesmelova, Irina V; Ermakova, Elena; Daragan, Vladimir A; Pang, Mabel; Menéndez, Margarita; Lagartera, Laura; Solís, Dolores; Baum, Linda G; Mayo, Kevin H

2010-04-16

Galectins are a family of lectins with a conserved carbohydrate recognition domain that interacts with beta-galactosides. By binding cell surface glycoconjugates, galectin-1 (gal-1) is involved in cell adhesion and migration processes and is an important regulator of tumor angiogenesis. Here, we used heteronuclear NMR spectroscopy and molecular modeling to investigate lactose binding to gal-1 and to derive solution NMR structures of gal-1 in the lactose-bound and unbound states. Structure analysis shows that the beta-strands and loops around the lactose binding site, which are more open and dynamic in the unbound state, fold in around the bound lactose molecule, dampening internal motions at that site and increasing motions elsewhere throughout the protein to contribute entropically to the binding free energy. CD data support the view of an overall more open structure in the lactose-bound state. Analysis of heteronuclear single quantum coherence titration binding data indicates that lactose binds the two carbohydrate recognition domains of the gal-1 dimer with negative cooperativity, in that the first lactose molecule binds more strongly (K(1)=21+/-6 x 10(3) M(-1)) than the second (K(2)=4+/-2 x 10(3) M(-1)). Isothermal calorimetry data fit using a sequential binding model present a similar picture, yielding K(1)=20+/-10 x 10(3) M(-1) and K(2)=1.67+/-0.07 x 10(3) M(-1). Molecular dynamics simulations provide insight into structural dynamics of the half-loaded lactose state and, together with NMR data, suggest that lactose binding at one site transmits a signal through the beta-sandwich and loops to the second binding site. Overall, our results provide new insight into gal-1 structure-function relationships and to protein-carbohydrate interactions in general. Copyright (c) 2010. Published by Elsevier Ltd.

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

PubMed

Lange, Florian; Eggert, Frank

2015-12-01

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

Direct labelling of the human P2X7 receptor and identification of positive and negative cooperativity of binding.

PubMed

Michel, A D; Chambers, L J; Clay, W C; Condreay, J P; Walter, D S; Chessell, I P

2007-05-01

The P2X(7) receptor exhibits complex pharmacological properties. In this study, binding of a [(3)H]-labelled P2X(7) receptor antagonist to human P2X(7) receptors has been examined to further understand ligand interactions with this receptor. The P2X(7) receptor antagonist, N-[2-({2-[(2-hydroxyethyl)amino]ethyl}amino)-5-quinolinyl]-2-tricyclo[3.3.1.1(3,7)]dec-1-ylacetamide (compound-17), was radiolabelled with tritium and binding studies were performed using membranes prepared from U-2 OS or HEK293 cells expressing human recombinant P2X(7) receptors. Binding of [(3)H]-compound-17 was higher in membranes prepared from cells expressing P2X(7) receptors than from control cells and was inhibited by ATP suggesting labelled sites represented human P2X(7) receptors. Binding was reversible, saturable and modulated by P2X(7) receptor ligands (Brilliant Blue G, KN62, ATP, decavanadate). Furthermore, ATP potency was reduced in the presence of divalent cations or NaCl. Radioligand binding exhibited both positive and negative cooperativity. Positive cooperativity was evident from bell shaped Scatchard plots, reduction in radioligand dissociation rate by unlabelled compound-17 and enhancement of radioligand binding by KN62 and unlabelled compound-17. ATP and decavanadate inhibited binding in a negative cooperative manner as they enhanced radioligand dissociation. These data demonstrate that human P2X(7) receptors can be directly labelled and provide novel insights into receptor function. The positive cooperativity observed suggests that binding of compound-17 to one subunit in the P2X(7) receptor complex enhances subsequent binding to other P2X(7) subunits in the same complex. The negative cooperative effects of ATP suggest that ATP and compound-17 bind at separate, interacting, sites on the P2X(7) receptor.

Direct labelling of the human P2X7 receptor and identification of positive and negative cooperativity of binding

PubMed Central

Michel, A D; Chambers, L J; Clay, W C; Condreay, J P; Walter, D S; Chessell, I P

2007-01-01

Background and Purpose: The P2X7 receptor exhibits complex pharmacological properties. In this study, binding of a [3H]-labelled P2X7 receptor antagonist to human P2X7 receptors has been examined to further understand ligand interactions with this receptor. Experimental Approach: The P2X7 receptor antagonist, N-[2-({2-[(2-hydroxyethyl)amino]ethyl}amino)-5-quinolinyl]-2-tricyclo[3.3.1.13,7]dec-1-ylacetamide (compound-17), was radiolabelled with tritium and binding studies were performed using membranes prepared from U-2 OS or HEK293 cells expressing human recombinant P2X7 receptors. Key Results: Binding of [3H]-compound-17 was higher in membranes prepared from cells expressing P2X7 receptors than from control cells and was inhibited by ATP suggesting labelled sites represented human P2X7 receptors. Binding was reversible, saturable and modulated by P2X7 receptor ligands (Brilliant Blue G, KN62, ATP, decavanadate). Furthermore, ATP potency was reduced in the presence of divalent cations or NaCl. Radioligand binding exhibited both positive and negative cooperativity. Positive cooperativity was evident from bell shaped Scatchard plots, reduction in radioligand dissociation rate by unlabelled compound-17 and enhancement of radioligand binding by KN62 and unlabelled compound-17. ATP and decavanadate inhibited binding in a negative cooperative manner as they enhanced radioligand dissociation. Conclusions: These data demonstrate that human P2X7 receptors can be directly labelled and provide novel insights into receptor function. The positive cooperativity observed suggests that binding of compound-17 to one subunit in the P2X7 receptor complex enhances subsequent binding to other P2X7 subunits in the same complex. The negative cooperative effects of ATP suggest that ATP and compound-17 bind at separate, interacting, sites on the P2X7 receptor. PMID:17339830

GPs' experiences with out-of-hours GP cooperatives: a survey study from the Netherlands.

PubMed

Smits, Marleen; Keizer, Ellen; Huibers, Linda; Giesen, Paul

2014-09-01

Out-of-hours primary care has been provided by general practitioner (GP) cooperatives since the year 2000 in the Netherlands. Early studies in countries with similar organizational structures showed positive GP experiences. However, nowadays it is said that GPs experience a high workload at the cooperative and that they outsource a considerable part of their shifts. To examine positive and negative experiences of GPs providing out-of-hours primary care, and the frequency and reasons for outsourcing shifts. A cross-sectional observational survey among 688 GPs connected to six GP cooperatives in the Netherlands, using a web-based questionnaire. The response was 55% (n = 378). The main reasons for working in GP cooperatives were to retain registration as GP (79%) and remain experienced in acute care (74%). GPs considered the peak hours (81%) and the high number of patients (73%) as the most negative aspects. Most GPs chose to provide the out-of-hours shifts themselves: 85% outsourced maximally 25% of their shifts. The percentage of outsourced shifts increased with age. Main reasons for outsourcing were the desire to have more private time (76%); the high workload in daytime practice (71%); and less the workload during out-of-hours (46%). GPs are motivated to work in out-of-hours GP cooperatives, and they outsource few shifts. GPs consider the peak load and the large number of (non-urgent) help requests as the most negative aspects. To motivate and involve GPs for 7 × 24-h primary care, it is important to set limits on their workload.

Why do parallel cortical systems exist for the perception of static form and moving form?

PubMed

Grossberg, S

1991-02-01

This article analyzes computational properties that clarify why the parallel cortical systems V1----V2, V1----MT, and V1----V2----MT exist for the perceptual processing of static visual forms and moving visual forms. The article describes a symmetry principle, called FM symmetry, that is predicted to govern the development of these parallel cortical systems by computing all possible ways of symmetrically gating sustained cells with transient cells and organizing these sustained-transient cells into opponent pairs of on-cells and off-cells whose output signals are insensitive to direction of contrast. This symmetric organization explains how the static form system (static BCS) generates emergent boundary segmentations whose outputs are insensitive to direction of contrast and insensitive to direction of motion, whereas the motion form system (motion BCS) generates emergent boundary segmentations whose outputs are insensitive to direction of contrast but sensitive to direction of motion. FM symmetry clarifies why the geometries of static and motion form perception differ--for example, why the opposite orientation of vertical is horizontal (90 degrees), but the opposite direction of up is down (180 degrees). Opposite orientations and directions are embedded in gated dipole opponent processes that are capable of antagonistic rebound. Negative afterimages, such as the MacKay and waterfall illusions, are hereby explained as are aftereffects of long-range apparent motion. These antagonistic rebounds help to control a dynamic balance between complementary perceptual states of resonance and reset. Resonance cooperatively links features into emergent boundary segmentations via positive feedback in a CC loop, and reset terminates a resonance when the image changes, thereby preventing massive smearing of percepts. These complementary preattentive states of resonance and reset are related to analogous states that govern attentive feature integration, learning, and memory search in adaptive resonance theory. The mechanism used in the V1----MT system to generate a wave of apparent motion between discrete flashes may also be used in other cortical systems to generate spatial shifts of attention. The theory suggests how the V1----V2----MT cortical stream helps to compute moving form in depth and how long-range apparent motion of illusory contours occurs. These results collectively argue against vision theories that espouse independent processing modules. Instead, specialized subsystems interact to overcome computational uncertainties and complementary deficiencies, to cooperatively bind features into context-sensitive resonances, and to realize symmetry principles that are predicted to govern the development of the visual cortex.

Kinetic Evidence of an Apparent Negative Activation Enthalpy in an Organocatalytic Process

PubMed Central

Han, Xiao; Lee, Richmond; Chen, Tao; Luo, Jie; Lu, Yixin; Huang, Kuo-Wei

2013-01-01

A combined kinetic and computational study on our tryptophan-based bifunctional thiourea catalyzed asymmetric Mannich reactions reveals an apparent negative activation enthalpy. The formation of the pre-transition state complex has been unambiguously confirmed and these observations provide an experimental support for the formation of multiple hydrogen bonding network between the substrates and the catalyst. Such interactions allow the creation of a binding cavity, a key factor to install high enantioselectivity. PMID:23990028

ΔNp73 overexpression promotes resistance to apoptosis but does not cooperate with PML/RARA in the induction of an APL-leukemic phenotype

PubMed Central

Lucena-Araujo, Antonio R.; Coelho-Silva, Juan L.; Pereira-Martins, Diego A.; Thomé, Carolina; Scheucher, Priscila S.; Lange, Ana P.; Paiva, Helder H.; Hemmelgarn, Benjamin T.; Morais-Sobral, Mariana C.; Azevedo, Elisa A.; Franca-Neto, Pedro L.; Franca, Rafael F.; Silva, Cleide L.; Krause, Alexandre; Rego, Eduardo M.

2017-01-01

Here, we evaluated whether the overexpression of transcriptionally inactive ΔNp73 cooperates with PML/RARA fusion protein in the induction of an APL-leukemic phenotype, as well as its role in vitro in proliferation, myeloid differentiation, and drug-induced apoptosis. Using lentiviral gene transfer, we showed in vitro that ΔNp73 overexpression resulted in increased proliferation in murine bone marrow (BM) cells from hCG-PML/RARA transgenic mice and their wild-type (WT) counterpart, with no accumulation of cells at G2/M or S phases; instead, ΔNp73-expressing cells had a lower rate of induced apoptosis. Next, we evaluated the effect of ΔNp73 on stem-cell self-renewal and myeloid differentiation. Primary BM cells lentivirally infected with human ΔNp73 were not immortalized in culture and did not present significant changes in the percentage of CD11b. Finally, we assessed the impact of ΔNp73 on leukemogenesis or its possible cooperation with PML/RARA fusion protein in the induction of an APL-leukemic phenotype. After 120 days of follow-up, all transplanted mice were clinically healthy and, no evidence of leukemia/myelodysplasia was apparent. Taken together, our data suggest that ΔNp73 had no leukemic transformation capacity by itself and apparently did not cooperate with the PML/RARA fusion protein to induce a leukemic phenotype in a murine BM transplantation model. In addition, the forced expression of ΔNp73 in murine BM progenitors did not alter the ATRA-induced differentiation rate in vitro or induce aberrant cell proliferation, but exerted an important role in cell survival, providing resistance to drug-induced apoptosis. PMID:28035072

Meeting now suggests we will meet again: Implications for debates on the evolution of cooperation

PubMed Central

Krasnow, Max M.; Delton, Andrew W.; Tooby, John; Cosmides, Leda

2013-01-01

Humans are often generous, even towards strangers encountered by chance and even in the absence of any explicit information suggesting they will meet again. Because game theoretic analyses typically conclude that a psychology designed for direct reciprocity should defect in such situations, many have concluded that alternative explanations for human generosity—explanations beyond direct reciprocity—are necessary. However, human cooperation evolved within a material and informational ecology: Simply adding consideration of one minimal ecological relationship to the analysis of reciprocity brings theory and observation closer together, indicating that ecology-free analyses of cooperation can be fragile. Using simulations, we show that the autocorrelation of an individual's location over time means that even a chance encounter with an individual predicts an increased probability of a future encounter with that same individual. We discuss how a psychology designed for such an ecology may be expected to often cooperate even in apparently one-shot situations. PMID:23624437

Misreporting behaviour in iterated prisoner's dilemma game with combined trust strategy

NASA Astrophysics Data System (ADS)

Chen, Bo; Zhang, Bin; Wu, Hua-qing

2015-01-01

Effects of agents' misreporting behaviour on system cooperation are studied in a multi-agent iterated prisoner's dilemma game. Agents, adopting combined trust strategy (denoted by CTS) are classified into three groups, i.e., honest CTS, positive-reporting CTS and negative-reporting CTS. The differences of cooperation frequency and pay-off under three different systems, i.e., system only with honest CTS, system with honest CTS and positive-reporting CTS and system with honest CTS and negative-reporting CTS, are compared. Furthermore, we also investigate the effects of misreporting behaviour on an exploiter who adopts an exploiting strategy (denoted by EXPL) in a system with two CTSs and one EXPL. At last, numerical simulations are performed for understanding the effects of misreporting behaviour on CTS. The results reveal that positive-reporting behaviour can strengthen system cooperation, while negative-reporting behaviour cannot. When EXPL exists in a system, positive-reporting behaviour helps the exploiter in reducing its exploiting cost and encourages agents to adopt exploiting strategy, but hurts other agents' interests.

Cooperation evolution in random multiplicative environments

NASA Astrophysics Data System (ADS)

Yaari, G.; Solomon, S.

2010-02-01

Most real life systems have a random component: the multitude of endogenous and exogenous factors influencing them result in stochastic fluctuations of the parameters determining their dynamics. These empirical systems are in many cases subject to noise of multiplicative nature. The special properties of multiplicative noise as opposed to additive noise have been noticed for a long while. Even though apparently and formally the difference between free additive vs. multiplicative random walks consists in just a move from normal to log-normal distributions, in practice the implications are much more far reaching. While in an additive context the emergence and survival of cooperation requires special conditions (especially some level of reward, punishment, reciprocity), we find that in the multiplicative random context the emergence of cooperation is much more natural and effective. We study the various implications of this observation and its applications in various contexts.

Ligand Binding to WW Tandem Domains of YAP2 Transcriptional Regulator Is Under Negative Cooperativity

PubMed Central

Schuchardt, Brett J.; Mikles, David C.; Hoang, Lawrence M.; Bhat, Vikas; McDonald, Caleb B.; Sudol, Marius; Farooq, Amjad

2014-01-01

YAP2 transcriptional regulator drives a multitude of cellular processes, including the newly discovered Hippo tumor suppressor pathway, by virtue of the ability of its WW domains to bind and recruit PPXY-containing ligands to specific subcellular compartments. Herein, we employ an array of biophysical tools to investigate allosteric communication between the WW tandem domains of YAP2. Our data show that the WW tandem domains of YAP2 negatively cooperate when binding to their cognate ligands. Moreover, the molecular origin of such negative cooperativity lies in an unfavorable entropic contribution to the overall free energy relative to ligand binding to isolated WW domains. Consistent with this notion, the WW tandem domains adopt a fixed spatial orientation such that the WW1 domain curves outwards and stacks onto the binding groove of WW2 domain, thereby sterically hindering ligand binding to both itself and its tandem partner. Although ligand binding to both WW domains disrupts such interdomain stacking interaction, they reorient themselves and adopt an alternative fixed spatial orientation in the liganded state by virtue of their ability to engage laterally so as to allow their binding grooves to point outwards and away from each other. In short, while the ability of WW tandem domains to aid ligand binding is well-documented, our demonstration that they may also be subject to negative binding cooperativity represents a paradigm shift in our understanding of the molecular action of this ubiquitous family of protein modules. PMID:25283809

CYP2E1 hydroxylation of aniline involves negative cooperativity.

PubMed

Hartman, Jessica H; Knott, Katie; Miller, Grover P

2014-02-01

CYP2E1 plays a role in the metabolic activation and elimination of aniline, yet there are conflicting reports on its mechanism of action, and hence relevance, in aniline metabolism. Based on our work with similar compounds, we hypothesized that aniline binds two CYP2E1 sites during metabolism resulting in cooperative reaction kinetics and tested this hypothesis through rigorous in vitro studies. The kinetic profile for recombinant CYP2E1 demonstrated significant negative cooperativity based on a fit of data to the Hill equation (n=0.56). Mechanistically, the data were best explained through a two-binding site cooperative model in which aniline binds with high affinity (K(s)=30 μM) followed by a second weaker binding event (K(ss)=1100 uM) resulting in a threefold increase in the oxidation rate. Binding sites for aniline were confirmed by inhibition studies with 4-methylpyrazole. Inhibitor phenotyping experiments with human liver microsomes validated the central role for CYP2E1 in aniline hydroxylation and indicated minor roles for CYP2A6 and CYP2C9. Importantly, inhibition of minor metabolic pathways resulted in a kinetic profile for microsomal CYP2E1 that replicated the preferred mechanism and parameters observed with the recombinant enzyme. Scaled modeling of in vitro CYP2E1 metabolism of aniline to in vivo clearance, especially at low aniline levels, led to significant deviations from the traditional model based on non-cooperative, Michaelis-Menten kinetics. These findings provide a critical mechanistic perspective on the potential importance of CYP2E1 in the metabolic activation and elimination of aniline as well as the first experimental evidence of a negatively cooperative metabolic reaction catalyzed by CYP2E1. Copyright © 2013 Elsevier Inc. All rights reserved.

Chaos and the evolution of cooperation.

PubMed

Nowak, M; Sigmund, K

1993-06-01

The "iterated prisoner's dilemma" is the most widely used model for the evolution of cooperation in biological societies. Here we show that a heterogeneous population consisting of simple strategies, whose behavior is totally specified by the outcome of the previous round, can lead to persistent periodic or highly irregular (chaotic) oscillations in the frequencies of the strategies and the overall level of cooperation. The levels of cooperation jump up and down in an apparently unpredictable fashion. Small recurrent and simultaneous invasion attempts (caused by mutation) can change the evolutionary dynamics from converging to an evolutionarily stable strategy to periodic oscillations and chaos. Evolution can be twisted away from defection, toward cooperation. Adding "generous tit-for-tat" greatly increases the overall level of cooperation and can lead to long periods of steady cooperation. Since May's paper [May, R. M. (1976) Nature (London) 261, 459-467], "simple mathematical models with very complicated dynamics" have been found in many biological applications, but here we provide an example of a biologically relevant evolutionary game whose dynamics display deterministic chaos. The simulations bear some resemblance to the irregular cycles displayed by the frequencies of host genotypes and specialized parasites in evolutionary "arms races" [Hamilton, W. D., Axelrod, R. & Tanese, R. (1990) Proc. Natl. Acad. Sci. USA 87, 3566-3573; Seger, J. (1988) Philos. Trans. R. Soc. London B 319, 541-555].

Hanbury Brown and Twiss correlations of Cooper pairs in helical liquids

NASA Astrophysics Data System (ADS)

Choi, Mahn-Soo

2014-01-01

We propose a Hanbury Brown and Twiss (HBT) experiment of Cooper pairs on the edge channels of quantum spin Hall insulators. The helical edge channels provide a well-defined beam of Cooper pairs and perfect Andreev reflections from superconductors. This allows our setup to be identical in spirit to the original HBT experiment. Interestingly, the cross correlation is always negative and provides no hint of the bosonic nature of Cooper pairs. This counterintuitive result is attributed to the perfect Andreev reflection and the true beam splitter in the setup.

Allosteric Models for Cooperative Polymerization of Linear Polymers

PubMed Central

Miraldi, Emily R.; Thomas, Peter J.; Romberg, Laura

2008-01-01

In the cytoskeleton, unfavorable nucleation steps allow cells to regulate where, when, and how many polymers assemble. Nucleated polymerization is traditionally explained by a model in which multistranded polymers assemble cooperatively, whereas linear, single-stranded polymers do not. Recent data on the assembly of FtsZ, the bacterial homolog of tubulin, do not fit either category. FtsZ can polymerize into single-stranded protofilaments that are stable in the absence of lateral interactions, but that assemble cooperatively. We developed a model for cooperative polymerization that does not require polymers to be multistranded. Instead, a conformational change allows subunits in oligomers to associate with high affinity, whereas a lower-affinity conformation is favored in monomers. We derive equations for calculating polymer concentrations, subunit conformations, and the apparent affinity of subunits for polymer ends. Certain combinations of equilibrium constants produce the sharp critical concentrations characteristic of cooperative polymerization. In these cases, the low-affinity conformation predominates in monomers, whereas virtually all polymers are composed of high-affinity subunits. Our model predicts that the three routes to forming HH dimers all involve unstable intermediates, limiting nucleation. The mathematical framework developed here can represent allosteric assembly systems with a variety of biochemical interpretations, some of which can show cooperativity, and others of which cannot. PMID:18502809

Conjugated Porphyrin Dimers: Cooperative Effects and Electronic Communication in Supramolecular Ensembles with C60.

PubMed

Moreira, Luis; Calbo, Joaquín; Aragó, Juan; Illescas, Beatriz M; Nierengarten, Iwona; Delavaux-Nicot, Béatrice; Ortí, Enrique; Martín, Nazario; Nierengarten, Jean-François

2016-11-30

Two new conjugated porphyrin-based systems (dimers 3 and 4) endowed with suitable crown ethers have been synthesized as receptors for a fullerene-ammonium salt derivative (1). Association constants in solution have been determined by UV-vis titration experiments in CH 2 Cl 2 at room temperature. The designed hosts are able to associate up to two fullerene-based guest molecules and present association constants as high as ∼5 × 10 8 M -1 . Calculation of the allosteric cooperative factor α for supramolecular complexes [3·1 2 ] and [4·1 2 ] showed a negative cooperative effect in both cases. The interactions accounting for the formation of the associates are based, first, on the complementary ammonium-crown ether interaction and, second, on the π-π interactions between the porphyrin rings and the C 60 moieties. Theoretical calculations have evidenced a significant decrease of the electron density in the porphyrin dimers 3 and 4 upon complexation of the first C 60 molecule, in good agreement with the negative cooperativity found in these systems. This negative effect is partially compensated by the stabilizing C 60 -C 60 interactions that take place in the more stable syn-disposition of [4·1 2 ].

Reconsidering the "Good Divorce"

ERIC Educational Resources Information Center

Amato, Paul R.; Kane, Jennifer B.; James, Spencer

2011-01-01

This study attempted to assess the notion that a "good divorce" protects children from the potential negative consequences of marital dissolution. A cluster analysis of data on postdivorce parenting from 944 families resulted in three groups: cooperative coparenting, parallel parenting, and single parenting. Children in the cooperative coparenting…

Prosocial Behavior and Subjective Insecurity in Violent Contexts: Field Experiments

PubMed Central

Vélez, María Alejandra; Trujillo, Carlos Andres; Moros, Lina; Forero, Clemente

2016-01-01

Subjective insecurity is a key determinant of different forms of prosocial behavior. In Study 1, we used field experiments with farmers in Colombian villages exposed to different levels of violence to investigate how individual perceptions of insecurity affect cooperation, trust, reciprocity and altruism. To do so, we developed a cognitive-affective measure of subjective insecurity. We found that subjective insecurity has a negative effect on cooperation but influences trust and altruism positively. In Study 2, carried out three years after Study 1, we repeated the initial design with additional measures of victimization. Our goal was to relate subjective insecurity with actual victimization. The findings of Study 2 support the initial results, and are robust and consistent for cooperative behavior and trust when including victimization as a mediator. Different indicators of victimization are positively correlated with subjective insecurity and an aggregate index of victimization has a negative effect on cooperation but exerts a positive influence on trust. PMID:27472437

TLR9 is required for MAPK/NF-κB activation but does not cooperate with TLR2 or TLR6 to induce host resistance to Brucella abortus.

PubMed

Gomes, Marco Túlio; Campos, Priscila Carneiro; Pereira, Guilherme de Sousa; Bartholomeu, Daniella Castanheira; Splitter, Gary; Oliveira, Sergio Costa

2016-05-01

Brucella abortus is a Gram-negative intracellular bacterial pathogen that causes a zoonosis of worldwide occurrence, leading to undulant fever in humans and abortion in domestic animals. B. abortus is recognized by several pattern-recognition receptors triggering pathways during the host innate immune response. Therefore, here, we determined the cooperative role of TLR9 with TLR2 or TLR6 receptors in sensing Brucella Furthermore, we deciphered the host innate immune response against B. abortus or its DNA, emphasizing the role of TLR9-MAPK/NF-κB signaling pathways in the production of proinflammatory cytokines. TLR9 is required for the initial host control of B. abortus, but this TLR was dispensable after 6 wk of infection. The susceptibility of TLR9(-/-)-infected animals to Brucella paralleled with lower levels of IFN-γ produced by mouse splenocytes stimulated with this pathogen compared with wild-type cells. However, no apparent cooperative interplay was observed between TLR2-TLR9 or TLR6-TLR9 receptors to control infection. Moreover, B. abortus or its DNA induced activation of MAPK/NF-κB pathways and production of IL-12 and TNF-α by macrophages partially dependent on TLR9 but completely dependent on MyD88. In addition, B. abortus-derived CpG oligonucleotides required TLR9 to promote IL-12 and TNF-α production by macrophages. By confocal microscopy, we demonstrated that TLR9 redistributed and colocalized with lysosomal-associated membrane protein-1 upon Brucella infection. Thus, B. abortus induced TLR9 traffic, leading to cell signaling activation and IL-12 and TNF-α production. Although TLR9 recognized Brucella CpG motifs, our results suggest a new pathway of B. abortus DNA-activating macrophages independent of TLR9. © Society for Leukocyte Biology.

Negative Affect during a Collective (but Not an Individual) Task Is Associated with Holistic Attention in East Asian Cultural Context

PubMed Central

Tominaga, Hitoshi; Uchida, Yukiko; Miyamoto, Yuri; Yamasaki, Teruo

2017-01-01

Previous studies have suggested that individuals from East Asian cultures are more likely to show holistic attention—a pattern of attention that incorporates contextual information into focal stimuli—than individuals from North American cultures. Holistic attention is also prevalent in communities that require close cooperation. However, it is not yet known how cooperation is related to holistic attention. We theorized that holistic attention increases when people experience negative affect (e.g., worry, sadness, and frustration) during collective tasks (but not during individual tasks) because negative affect in social contexts signals the existence of potential threats to social harmony, thus indicating a need to restore social harmony. To examine this hypothesis, an experiment was conducted in which participants performed a musical duet either with another participant (a collective task requiring cooperation), or individually with a computer (an individual task). After the musical task, the Framed Line Task (FLT) was administered to examine their holistic attention. Participants also reported their emotional states both before and after the music task. Results suggested that negative affect in the collective task—but not the individual task—was positively correlated with a holistic pattern of attention. The function of negative affect in social contexts as motivation to restore relationships and how this enhances holistic attention is discussed. The moderating effect of social context on the link between negative affect and cognition is also discussed. PMID:28824483

With a little help from my assistant: buffering the negative effects of emotional dissonance on dentist performance.

PubMed

Rodríguez-Sánchez, Alma M; Hakanen, Jari J; Perhoniemi, Riku; Salanova, Marisa

2013-10-01

In this study, we hypothesized that dentist' interpersonal resources (good cooperation with one's assistant) together with their personal resources (optimism) buffer the negative effects of emotional dissonance (a demand that occurs when there is a difference between felt and displayed emotions) on job performance (in-role and extra-role performance) over time. We carried out Hierarchical Regression Modeling on a sample of 1954 Finnish dentists who participated in a two-wave 4-year longitudinal study. Results showed that good cooperation with dental assistants buffered the negative effects of emotional dissonance on both in-role and extra-role performance among the dentists in the long term. However, unexpectedly, dentists' high optimism did not buffer their in-role nor extra-role performance over time under conditions of experiencing high emotional dissonance. We conclude that interpersonal job resources such as good cooperation with one's colleagues may buffer the negative effect of emotional dissonance on dentists' job performance even in the long term, whereas the role of personal resources (e.g., optimism) may be less important for maintaining high job performance under conditions of emotional dissonance. The study novelties include the test of the negative effects of emotional dissonance on long-term performance in dentistry and the identification of the job rather than personal resources as the buffers against the negative effects of emotional dissonance on long-term performance. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Negative Affect during a Collective (but Not an Individual) Task Is Associated with Holistic Attention in East Asian Cultural Context.

PubMed

Tominaga, Hitoshi; Uchida, Yukiko; Miyamoto, Yuri; Yamasaki, Teruo

2017-01-01

Previous studies have suggested that individuals from East Asian cultures are more likely to show holistic attention-a pattern of attention that incorporates contextual information into focal stimuli-than individuals from North American cultures. Holistic attention is also prevalent in communities that require close cooperation. However, it is not yet known how cooperation is related to holistic attention. We theorized that holistic attention increases when people experience negative affect (e.g., worry, sadness, and frustration) during collective tasks (but not during individual tasks) because negative affect in social contexts signals the existence of potential threats to social harmony, thus indicating a need to restore social harmony. To examine this hypothesis, an experiment was conducted in which participants performed a musical duet either with another participant (a collective task requiring cooperation), or individually with a computer (an individual task). After the musical task, the Framed Line Task (FLT) was administered to examine their holistic attention. Participants also reported their emotional states both before and after the music task. Results suggested that negative affect in the collective task-but not the individual task-was positively correlated with a holistic pattern of attention. The function of negative affect in social contexts as motivation to restore relationships and how this enhances holistic attention is discussed. The moderating effect of social context on the link between negative affect and cognition is also discussed.

Different responses to reward comparisons by three primate species.

PubMed

Freeman, Hani D; Sullivan, Jennifer; Hopper, Lydia M; Talbot, Catherine F; Holmes, Andrea N; Schultz-Darken, Nancy; Williams, Lawrence E; Brosnan, Sarah F

2013-01-01

Recently, much attention has been paid to the role of cooperative breeding in the evolution of behavior. In many measures, cooperative breeders are more prosocial than non-cooperatively breeding species, including being more likely to actively share food. This is hypothesized to be due to selective pressures specific to the interdependency characteristic of cooperatively breeding species. Given the high costs of finding a new mate, it has been proposed that cooperative breeders, unlike primates that cooperate in other contexts, should not respond negatively to unequal outcomes between themselves and their partner. However, in this context such pressures may extend beyond cooperative breeders to other species with pair-bonding and bi-parental care. Here we test the response of two New World primate species with different parental strategies to unequal outcomes in both individual and social contrast conditions. One species tested was a cooperative breeder (Callithrix spp.) and the second practiced bi-parental care (Aotus spp.). Additionally, to verify our procedure, we tested a third confamilial species that shows no such interdependence but does respond to individual (but not social) contrast (Saimiri spp.). We tested all three genera using an established inequity paradigm in which individuals in a pair took turns to gain rewards that sometimes differed from those of their partners. None of the three species tested responded negatively to inequitable outcomes in this experimental context. Importantly, the Saimiri spp responded to individual contrast, as in earlier studies, validating our procedure. When these data are considered in relation to previous studies investigating responses to inequity in primates, they indicate that one aspect of cooperative breeding, pair-bonding or bi-parental care, may influence the evolution of these behaviors. These results emphasize the need to study a variety of species to gain insight in to how decision-making may vary across social structures.

Enhancing Social Work Education through Team-Based Learning

ERIC Educational Resources Information Center

Gillespie, Judy

2012-01-01

Group learning strategies are used extensively in social work education, despite the challenges and negative outcomes regularly experienced by students and faculty. Building on principles of cooperative learning, team-based learning offers a more structured approach that maximizes the benefits of cooperative learning while also offering…

Monkeys reject unequal pay.

PubMed

Brosnan, Sarah F; De Waal, Frans B M

2003-09-18

During the evolution of cooperation it may have become critical for individuals to compare their own efforts and pay-offs with those of others. Negative reactions may occur when expectations are violated. One theory proposes that aversion to inequity can explain human cooperation within the bounds of the rational choice model, and may in fact be more inclusive than previous explanations. Although there exists substantial cultural variation in its particulars, this 'sense of fairness' is probably a human universal that has been shown to prevail in a wide variety of circumstances. However, we are not the only cooperative animals, hence inequity aversion may not be uniquely human. Many highly cooperative nonhuman species seem guided by a set of expectations about the outcome of cooperation and the division of resources. Here we demonstrate that a nonhuman primate, the brown capuchin monkey (Cebus apella), responds negatively to unequal reward distribution in exchanges with a human experimenter. Monkeys refused to participate if they witnessed a conspecific obtain a more attractive reward for equal effort, an effect amplified if the partner received such a reward without any effort at all. These reactions support an early evolutionary origin of inequity aversion.

Negative association between parental care and sibling cooperation in earwigs: a new perspective on the early evolution of family life?

PubMed

Kramer, J; Thesing, J; Meunier, J

2015-07-01

The evolution of family life requires net fitness benefits for offspring, which are commonly assumed to mainly derive from parental care. However, an additional source of benefits for offspring is often overlooked: cooperative interactions among juvenile siblings. In this study, we examined how sibling cooperation and parental care could jointly contribute to the early evolution of family life. Specifically, we tested whether the level of food transferred among siblings (sibling cooperation) in the European earwig Forficula auricularia (1) depends on the level of maternal food provisioning (parental care) and (2) is translated into offspring survival, as well as female investment into future reproduction. We show that higher levels of sibling food transfer were associated with lower levels of maternal food provisioning, possibly reflecting a compensatory relationship between sibling cooperation and maternal care. Furthermore, the level of sibling food transfer did not influence offspring survival, but was associated with negative effects on the production of the second and terminal clutch by the tending mothers. These findings indicate that sibling cooperation could mitigate the detrimental effects on offspring survival that result from being tended by low-quality mothers. More generally, they are in line with the hypothesis that sibling cooperation is an ancestral behaviour that can be retained to compensate for insufficient levels of parental investment. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

The D-galactose specific lectin of field bean (Dolichos lablab) seed binds sugars with extreme negative cooperativity and half-of-the-sites binding.

PubMed

Rao, Devavratha H; Gowda, Lalitha R

2012-08-15

The field bean (Dolichos lablab) lectin designated as PPO-haemagglutinin (DLL-II) is bifunctional, exhibiting both polyphenol oxidase and haemagglutinating activity. The lectin is unusual in that it binds galactose (Gal), lactose (Lac) and N-acetylgalactosamine (GalNAc) only in the presence of (NH₄)₂SO₄ and exhibits negative cooperativity and half-of-the-sites binding. Circular dichroism, isothermal titration calorimetry and fluorescence quenching were used to assess the sugar binding in the presence of (NH₄)₂O₄. Comparison of the near-UV CD spectra with and without bound sugar revealed ligand induced conformational changes. The intrinsic fluorescence quenching data indicate that DLL-II exhibits weak binding to Gal in the presence of (NH₄)₂SO₄ with a stoichiometry of one bound ligand per dimer. ITC data fitted using a two sets of sites binding model presented a similar picture. The K(a)'s for Gal, Lac and GalNAc in the presence of (NH₄)₂SO₄ were 0.16±0.002, 0.21±0.004 and 8.45±0.78 (×10⁻³) M⁻¹ respectively. The Hill plot for the binding of these sugars to DLL-II was curvilinear with a tangent slope <1.0 indicating negative cooperativity. DLL-II thus exhibits half-of-the-site binding, an extreme form of negative cooperativity in which the second ligand does not bind at all. This is the first report of a legume lectin, exhibiting half-of-the-sites binding. Copyright © 2012 Elsevier Inc. All rights reserved.

Ligand binding to WW tandem domains of YAP2 transcriptional regulator is under negative cooperativity.

PubMed

Schuchardt, Brett J; Mikles, David C; Hoang, Lawrence M; Bhat, Vikas; McDonald, Caleb B; Sudol, Marius; Farooq, Amjad

2014-12-01

YES-associated protein 2 (YAP2) transcriptional regulator drives a multitude of cellular processes, including the newly discovered Hippo tumor suppressor pathway, by virtue of the ability of its WW domains to bind and recruit PPXY-containing ligands to specific subcellular compartments. Herein, we employ an array of biophysical tools to investigate allosteric communication between the WW tandem domains of YAP2. Our data show that the WW tandem domains of YAP2 negatively cooperate when binding to their cognate ligands. Moreover, the molecular origin of such negative cooperativity lies in an unfavorable entropic contribution to the overall free energy relative to ligand binding to isolated WW domains. Consistent with this notion, the WW tandem domains adopt a fixed spatial orientation such that the WW1 domain curves outwards and stacks onto the binding groove of the WW2 domain, thereby sterically hindering ligand binding to both itself and its tandem partner. Although ligand binding to both WW domains disrupts such interdomain stacking interaction, they reorient themselves and adopt an alternative fixed spatial orientation in the liganded state by virtue of their ability to engage laterally so as to allow their binding grooves to point outwards and away from each other. In short, while the ability of WW tandem domains to aid ligand binding is well documented, our demonstration that they may also be subject to negative binding cooperativity represents a paradigm shift in our understanding of the molecular action of this ubiquitous family of protein modules. © 2014 FEBS.

Cooperative Learning: Middle School Students' Math Perceptions

ERIC Educational Resources Information Center

Odom, Rhonda

2010-01-01

Many American middle school students have negative perceptions of mathematics that could be impacting math achievement. Previous studies have examined the impact of cooperative learning on mathematics achievement and not on attitudes. The purpose of this quasi-experimental quantitative study was to measure the effect of Student Teams Achievement…

Group size adjustment to ecological demand in a cooperative breeder.

PubMed

Zöttl, Markus; Frommen, Joachim G; Taborsky, Michael

2013-04-07

Environmental factors can determine which group size will maximize the fitness of group members. This is particularly important in cooperative breeders, where group members often serve different purposes. Experimental studies are yet lacking to check whether ecologically mediated need for help will change the propensity of dominant group members to accept immigrants. Here, we manipulated the perceived risk of predation for dominant breeders of the cooperatively breeding cichlid fish Neolamprologus pulcher to test their response to unrelated and previously unknown immigrants. Potential immigrants were more readily accepted if groups were exposed to fish predators or egg predators than to herbivorous fish or control situations lacking predation risk. Our data are consistent with both risk dilution and helping effects. Egg predators were presented before spawning, which might suggest that the fish adjust acceptance rates also to a potential future threat. Dominant group members of N. pulcher apparently consider both present and future need of help based on ecological demand. This suggests that acceptance of immigrants and, more generally, tolerance of group members on demand could be a widespread response to ecological conditions in cooperatively breeding animals.

Robust Reputations for Peer-to-peer Markets

DTIC Science & Technology

2007-05-24

in all the example markets we examined. Of course, this strategy allows the seller to mitigate a great deal of risk: if a buyer does not pay, the...larger values of T relative to R make agents somewhat more willing to try non-cooperative strategies while more a more negative S causes agents to be...allows the market to converge to a cooperative state in the transaction game. The strategies employed by agents in such a cooperative market need not

When Cooperation Was Efficient or Inefficient. Functional Near-Infrared Spectroscopy Evidence

PubMed Central

Balconi, Michela; Vanutelli, Maria E.

2017-01-01

Cooperation is a construct within social cognition that requires both self-perception and the comprehension of others' actions. In the case of synchronized activities the adoption of common strategies is crucial, but this process can be strongly influenced by those variables. In fact, self-perceived efficacy within the social exchange can affect the motivational components toward the creation of synergic actions. Thus, what happens when our performance is efficient or inefficient during cooperation? This question was answered in the present study where we compared behavioral performance and neural activation across different conditions where subjects received an external feedback assessing a good or a poor outcome during a cooperative game. The request was to synchronize responses in a way to achieve good cooperation scorings. Results showed that the behavioral performance was affected by feedback valence, since the negative feedback induced a significant worse performance in contrast to the positive one, which significantly increased performance. For what concerns neural activation, data from functional near-infrared spectroscopy (fNIRS) showed a specific lateralization effect with the right DLPFC recruited in the case of negative feedback, and an opposite left-sided effect in the case of a positive feedback. Findings were interpreted by proposing that the inefficient condition could be similar to a competitive context since the perception of a failed joint action could have frustrated the cooperative attitude and the use of joint strategies. PMID:28536508

Draft Genome Sequences of Pseudomonas fluorescens BS2 and Pusillimonas noertemannii BS8, Soil Bacteria That Cooperate To Degrade the Poly-γ-d-Glutamic Acid Anthrax Capsule.

PubMed

Stabler, Richard A; Negus, David; Pain, Arnab; Taylor, Peter W

2013-01-01

A mixed culture of Pseudomonas fluorescens BS2 and Pusillimonas noertemannii BS8 degraded poly-γ-d-glutamic acid; when the 2 strains were cultured separately, no hydrolytic activity was apparent. Here we report the draft genome sequences of both soil isolates.

First-principles calculation of the bulk photovoltaic effect in bismuth ferrite.

PubMed

Young, Steve M; Zheng, Fan; Rappe, Andrew M

2012-12-07

We compute the bulk photovoltaic effect (BPVE) in BiFeO(3) using first-principles shift current theory, finding good agreement with experimental results. Furthermore, we reconcile apparently contradictory observations: by examining the contributions of all photovoltaic response tensor components and accounting for the geometry and ferroelectric domain structure of the experimental system, we explain the apparent lack of BPVE response in striped polydomain samples that is at odds with the significant response observed in monodomain samples. We reveal that the domain-wall-driven response in striped polydomain samples is partially mitigated by the BPVE, suggesting that enhanced efficiency could be obtained in materials with cooperative rather than antagonistic interaction between the two mechanisms.

Multinational investigation of cross-societal cooperation.

PubMed

Dorrough, Angela Rachael; Glöckner, Andreas

2016-09-27

In a globalized world, establishing successful cooperation between people from different nations is becoming increasingly important. We present results from a comprehensive investigation of cross-societal cooperation in one-shot prisoner's dilemmas involving population-representative samples from six countries and identify crucial facilitators of and obstacles to cooperation. In interactions involving mutual knowledge about only the other players' nationalities, we demonstrate that people hold strong and transnationally shared expectations (i.e., stereotypes) concerning the cooperation level of interaction partners from other countries. These expectations are the strongest determinants of participant cooperation. Paradoxically, however, they turn out to be incorrect stereotypes that even correlate negatively with reality. In addition to erroneous expectations, participants' cooperation behavior is driven by (shared) social preferences that vary according to the interaction partner's nationality. In the cross-societal context, these social preferences are influenced by differences in wealth and ingroup favoritism, as well as effects of specific country combinations but not by spatial distance between nations.

Reducing the Effect of Stereotype Threat: The Role of Coaction Contexts and Regulatory Fit

ERIC Educational Resources Information Center

Wen, Fangfang; Zuo, Bin; Wu, Yang; Dong, Xuanhao; Wang, Wei

2016-01-01

Two experiments examined the effects of competition and cooperation contexts, as well as regulatory fit, on reducing the negative influence of stereotype threat. Experiment 1 demonstrated that in high stereotype threat conditions, participants in the cooperation context scored significantly higher on a math test than those in the competition…

The Spreading of Social Energy: How Exposure to Positive and Negative Social News Affects Behavior.

PubMed

Yao, Ziqing; Yu, Rongjun

2016-01-01

Social news, unlike video games or TV programs, conveys real-life interactions. Theoretically, social news in which people help or harm each other and violate rules should influence both prosocial and violation behaviors. In two experiments, we demonstrated the spreading effects of social news in a social interaction context emphasizing social conventions and a nonsocial interaction context emphasizing moral norms. Across the two studies, the results showed that positive social news increased cooperation (decreased defection) but had no effect on cheating, whereas negative social news increased cheating but with no change in cooperation (or defection). We conclude that there is a spreading impact of positive social news in the conventional norm domain and of negative social news in the moral norm domain.

The Spreading of Social Energy: How Exposure to Positive and Negative Social News Affects Behavior

PubMed Central

Yao, Ziqing; Yu, Rongjun

2016-01-01

Social news, unlike video games or TV programs, conveys real-life interactions. Theoretically, social news in which people help or harm each other and violate rules should influence both prosocial and violation behaviors. In two experiments, we demonstrated the spreading effects of social news in a social interaction context emphasizing social conventions and a nonsocial interaction context emphasizing moral norms. Across the two studies, the results showed that positive social news increased cooperation (decreased defection) but had no effect on cheating, whereas negative social news increased cheating but with no change in cooperation (or defection). We conclude that there is a spreading impact of positive social news in the conventional norm domain and of negative social news in the moral norm domain. PMID:27253877

Causes of false-negative for high-grade urothelial carcinoma in urine cytology.

PubMed

Lee, Paul J; Owens, Christopher L; Lithgow, Marie Y; Jiang, Zhong; Fischer, Andrew H

2016-12-01

The Paris System for classifying urine cytology emphasizes identification of high-grade urothelial carcinoma (HGUC). The causes of false-negative urine cytologies (UC) within this system are not well described. We identified 660 cases between 2005 and 2013 with both UC and subsequent cystoscopic biopsies. UC were classified as either Negative for HGUC or "Abnormal" ("Atypical", "Suspicious", and "Malignant"). Apparent false-negative cases were reviewed in a nonblinded fashion by two cytopathologists and two subspecialized genitourinary pathologists. A total of 199 of the 660 cases (30%) were histologically diagnosed as HGUC. The UC were "Abnormal" in 170/199 cases (sensitivity/specificity of 86%/71%). Twenty four apparent false negative cases were available for retrospective review. Five of 24 (21%) cystoscopic biopsies were found not to be HGUC on review (one false positive and four low-grade urothelial carcinoma (LGUC on review). Of the remaining 19 UC, 7 (29%) cytology samples were found to be truly negative on review, 11 (46%) were found to be Atypical, and 1 (4%) suspicious. Of the 12 UC that were at least "Atypical" with histologic HGUC on review: six misses (half) were attributed to obscuring inflammation/blood, four to poor preservation, eight to paucity of abnormal cells, and 1 case to interpretive error; many cases demonstrated overlapping reasons. About one fifth of apparent false negative diagnoses for HGUC can be because of overdiagnosis of HGUC by surgical pathologists. If poor preservation or obscured samples are called nondiagnostic, the sensitivity/specificity of UC for HGUC can be as high as 94%/71%. Diagn. Cytopathol. 2016;44:994-999. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Funding oncology clinical trials: are cooperative group trials sustainable?

PubMed

Seow, Hsien-Yeang; Whelan, Patrick; Levine, Mark N; Cowan, Kathryn; Lysakowski, Barbara; Kowaleski, Brenda; Snider, Anne; Xu, Rebecca Y; Arnold, Andrew

2012-05-01

Many oncology clinical trials departments (CTDs) are in serious fiscal deficit and their sustainability is in jeopardy. This study investigates whether the payment models used to fund industry versus cooperative group trials contribute to the fiscal deficit of a CTD. We examined the lifetime costs of all cooperative group and industry trials activated in the CTD of a cancer center between 2007 and 2011. A trial's lifetime is defined as being from the date the first patient was accrued until the last patient's actual or projected final follow-up visit. For each trial, we calculated the lifetime monthly net income, which was defined as monthly revenue minus monthly costs. Data sources included study protocols, trial budgets, and accrual data. Of the 97 trials analyzed, 64 (66%) were cooperative group trials. The pattern of lifetime net income for cooperative group trials has a positive peak during patient accrual followed by a negative trough during follow-up. In contrast, the pattern for industry trials resembled an "l" shape. The patterns reflect the differing payment models: upfront lump-sum payments (cooperative group) versus milestone payments (industry). The negative trough in the lifetime net income of a cooperative group trial occurs because follow-up costs are typically not funded or are underfunded. CTDs accrue more patients in new trials to offset that deficit. The CTD uses revenue from accrual to existing trials to cross-subsidize past trials in follow-up. As the number of patients on follow-up increases, the fiscal deficit grows larger each year, perpetuating the cycle.

Human Cooperation and Its Underlying Mechanisms.

PubMed

Strang, Sabrina; Park, Soyoung Q

Cooperation is a uniquely human behavior and can be observed across cultures. In order to maintain cooperative behavior in society, people are willing to punish deviant behavior on their own expenses and even without any personal benefits. Cooperation has been object of research in several disciplines. Psychologists, economists, sociologists, biologists, and anthropologists have suggested several motives possibly underlying cooperative behavior. In recent years, there has been substantial progress in understanding neural mechanisms enforcing cooperation. Psychological as well as economic theories were tested for their plausibility using neuroscientific methods. For example, paradigms from behavioral economics were adapted to be tested in the magnetic resonance imaging (MRI) scanner. Also, related brain functions were modulated by using transmagnetic brain stimulation (TMS). While cooperative behavior has often been associated with positive emotions, noncooperative behavior was found to be linked to negative emotions. On a neural level, the temporoparietal junction (TPJ), the striatum, and other reward-related brain areas have been shown to be activated by cooperation, whereas noncooperation has mainly been associated with activity in the insula.

Energetic studies on DNA-peptide interaction in relation to the enthalpy-entropy compensation paradox.

PubMed

Yang, Robin C K; Huang, Jonathan T B; Chien, Shih-Chuan; Huang, Roy; Jeng, Kee-Ching G; Chen, Yen-Chung; Liao, Mokai; Wu, Jia-Rong; Hung, Wei-Kang; Hung, Chia-Chun; Chen, Yu-Ling; Waring, Michael J; Sheh, Leung

2013-01-07

This study aims to interpret the energetic basis of complex DNA-peptide interactions according to a novel allosteric interaction network approach. In common with other designed peptides, five new conjugates incorporating the XPRK or XHypRK motif (Hyp = hydroxyproline) attached to a N-methylpyrrole (Py) tract with a basic tail have been found to display cooperative binding to DNA involving multiple monodentate as well as interstrand bidentate interactions. Using quantitative DNase I footprinting it appears that allosteric communication via cooperative binding to multiple sites on complementary DNA strands corresponds to two different types of DNA-peptide interaction network. Temperature variation experiments using a dodecapeptide RY-12 show that lower temperature (25 °C) favor a circuit type of allosteric interaction network, whereas higher temperatures (31 and 37 °C) afford only a partial-circuit type of network. Circular dichroism studies show that our five peptides induce significant local conformational changes in DNA via the minor groove, with apparently dimeric binding stoichiometry. Isothermal titration calorimetry reveals that these peptides, together with another seven for comparison, are strongly exothermic upon binding to a model 13-mer DNA duplex, characterized by ΔH ranging from -14.7 to -74.4 kcal mol(-1), and also high TΔS ranging from -6.5 to -65.9 kcal mol(-1). Multiple monodentate and bidentate interactions, as well as ionic forces that mediate positive cooperativity in sequence recognition, are consistent with a dramatic decrease in entropy and a 'tightening' effect of DNA conformation. Distinctive enthalpy-entropy compensation (EEC) relationships are demonstrated for the interaction of all twelve designed peptides with DNA, affording a straight line of slope close to unity when ΔH is plotted versus TΔS, with a y-axis intercept (average ΔG) corresponding to -8.5 kcal mol(-1), while the observed ΔG ranges from -8.2 to -9.1 kcal mol(-1) for the peptides. The EEC seen with peptide RY-12 binding to the model duplex persists throughout various incubation temperatures. The net compensation of energy between the favorable negative ΔH and unfavorable negative ΔS components thus constrains the value of net binding free energy ΔG within a remarkably constant range, as is clearly visible in a 3-dimensional energetic plot. We conclude that the preservation of a rather narrowly-defined ΔG value is central to the EEC in DNA-peptide interactions, illuminating the universal EEC paradox commonly found in diverse biochemical reactions.

3D numerical modelling of negative apparent conductivity anomalies in loop-loop electromagnetic measurements: a case study at a dacite intrusion in Sugisawa, Akita Prefecture, Japan

NASA Astrophysics Data System (ADS)

Selepeng, Ame Thato; Sakanaka, Shin'ya; Nishitani, Tadashi

2017-04-01

Under certain geological conditions, low induction number electromagnetic (LIN-EM) instruments are known to produce negative apparent conductivity (σa) responses. This is particularly the case when the shallow subsurface is characterised by highly conductive bodies, however little attention has been given to this issue in the research literature. To analyse negative σa anomalies and their causative structures, we make use of a 3D integral equation forward modelling technique based on a 3D weighting function. We present 3D numerical modelling results over a volcanic tuff body intruded by several dacite dikes, in Sugisawa, Akita Prefecture, Japan. Apparent conductivity data were acquired using a Geonics EM-34-3 system in the horizontal magnetic dipole (HMD) and vertical magnetic dipole (VMD) operating modes. Our 3D model resolved the horizontal and vertical extent of the dacite dikes and also delineated a high conductive zone between the volcanic tuff and the intrusive dacite dikes. This zone is the causative structure for negative σa responses in the VMD data, and is interpreted to be an alteration zone. Interestingly, the negative σa response was absent when the instrument alignment azimuth was changed, implying an anisotropic effect on the EM signature in the study area. The true conductivity model achieved by 3D forward modelling is shown to compare favourably with the DC resistivity data acquired in the same area.

Stags, Hawks, and Doves: Social Evolution Theory and Individual Variation in Cooperation.

PubMed

Van Cleve, Jeremy

2017-09-01

One of the triumphs of evolutionary biology is the discovery of robust mechanisms that promote the evolution of cooperative behaviors even when cooperation reduces the fertility or survival of cooperators. These mechanisms include, kin selection, reciprocity, and direct benefits to cooperation that are often nonlinear. Though they have been extensively studied separately, investigating the joint action of these mechanisms has been more difficult. Moreover, how these mechanisms shape variation in cooperation is not well known. Such variation is crucial for understanding the evolution of behavioral syndromes and animal personality. Here, I use the tools of kin selection and evolutionary game theory to build a framework that integrates these mechanisms for pairwise social interactions. Using relatedness as a measure of the strength of kin selection, responsiveness as a measure of reciprocity, and synergy as a measure of payoff nonlinearity, I show how different combinations of these three parameters produce directional selection for or against cooperation or variation in levels of cooperation via stabilizing or diversifying selection. Moreover, each of these outcomes maps uniquely to one of four classic games from evolutionary game theory, which means that modulating relatedness, responsiveness, and synergy effectively transforms the payoff matrix from one the evolutionary game to another. Assuming that cooperation exacts a fertility cost on cooperators and provides a fertility benefit to social partners, a prisoner's dilemma game and directional selection against cooperation occur when relatedness and responsiveness are low and synergy is not too positive. Enough positive synergy in these conditions generates a stag-hunt game and diversifying selection. High levels of relatedness or responsiveness turn cooperation from a fitness cost into a fitness benefit, which produces a mutualism game and directional selection for cooperation when synergy is not too negative. Sufficiently negative synergy in this case creates a hawk-dove game and stabilizing selection for cooperation. I extend the results with relatedness and synergy to social groups and show that how group size changes the effect of relatedness and synergy on selection for cooperation depends on how the per capita benefit of cooperation changes with group size. Together, these results provide a general framework with which to generate comparative predictions that can be tested using quantitative genetic techniques and experimental techniques that manipulate investment in cooperation. These predictions will help us understand both interspecific variation in cooperation as well as within-population and within-group variation in cooperation related to behavioral syndromes. © The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

East Europe Report.

DTIC Science & Technology

1986-01-21

modernization of the Hungarian banking system has apparently affected the National Savings Bank as well. The accounts on the refurbishing of...new cars The rule currently in effect is an old decree by theMinltry of Domestic Commerce, and it only affects deposits on purchases in general...the relations of close friendship and fruitful cooperation between the SR of Romania and the PDR of Yemen will continue to develop both bilaterally

BMI1 and H-RAS Cooperate to Drive Breast Cancer Metastasis | Center for Cancer Research

Cancer.gov

There have been significant improvements in the diagnosis of breast cancer at early stages of the disease. However, even when patients are identified early, there is a 30 percent chance of recurrence after apparently successful treatment of the initial tumor. The major cause of death for breast cancer patients is metastasis of the tumor to other organs but, unfortunately, the

The Effect of Incentives and Meta-incentives on the Evolution of Cooperation.

PubMed

Okada, Isamu; Yamamoto, Hitoshi; Toriumi, Fujio; Sasaki, Tatsuya

2015-05-01

Although positive incentives for cooperators and/or negative incentives for free-riders in social dilemmas play an important role in maintaining cooperation, there is still the outstanding issue of who should pay the cost of incentives. The second-order free-rider problem, in which players who do not provide the incentives dominate in a game, is a well-known academic challenge. In order to meet this challenge, we devise and analyze a meta-incentive game that integrates positive incentives (rewards) and negative incentives (punishments) with second-order incentives, which are incentives for other players' incentives. The critical assumption of our model is that players who tend to provide incentives to other players for their cooperative or non-cooperative behavior also tend to provide incentives to their incentive behaviors. In this paper, we solve the replicator dynamics for a simple version of the game and analytically categorize the game types into four groups. We find that the second-order free-rider problem is completely resolved without any third-order or higher (meta) incentive under the assumption. To do so, a second-order costly incentive, which is given individually (peer-to-peer) after playing donation games, is needed. The paper concludes that (1) second-order incentives for first-order reward are necessary for cooperative regimes, (2) a system without first-order rewards cannot maintain a cooperative regime, (3) a system with first-order rewards and no incentives for rewards is the worst because it never reaches cooperation, and (4) a system with rewards for incentives is more likely to be a cooperative regime than a system with punishments for incentives when the cost-effect ratio of incentives is sufficiently large. This solution is general and strong in the sense that the game does not need any centralized institution or proactive system for incentives.

The Effect of Incentives and Meta-incentives on the Evolution of Cooperation

PubMed Central

Okada, Isamu; Yamamoto, Hitoshi; Toriumi, Fujio; Sasaki, Tatsuya

2015-01-01

Although positive incentives for cooperators and/or negative incentives for free-riders in social dilemmas play an important role in maintaining cooperation, there is still the outstanding issue of who should pay the cost of incentives. The second-order free-rider problem, in which players who do not provide the incentives dominate in a game, is a well-known academic challenge. In order to meet this challenge, we devise and analyze a meta-incentive game that integrates positive incentives (rewards) and negative incentives (punishments) with second-order incentives, which are incentives for other players’ incentives. The critical assumption of our model is that players who tend to provide incentives to other players for their cooperative or non-cooperative behavior also tend to provide incentives to their incentive behaviors. In this paper, we solve the replicator dynamics for a simple version of the game and analytically categorize the game types into four groups. We find that the second-order free-rider problem is completely resolved without any third-order or higher (meta) incentive under the assumption. To do so, a second-order costly incentive, which is given individually (peer-to-peer) after playing donation games, is needed. The paper concludes that (1) second-order incentives for first-order reward are necessary for cooperative regimes, (2) a system without first-order rewards cannot maintain a cooperative regime, (3) a system with first-order rewards and no incentives for rewards is the worst because it never reaches cooperation, and (4) a system with rewards for incentives is more likely to be a cooperative regime than a system with punishments for incentives when the cost-effect ratio of incentives is sufficiently large. This solution is general and strong in the sense that the game does not need any centralized institution or proactive system for incentives. PMID:25974684

A form of 'parental presence/absence' (PPA) technique for the child patient with dental behaviour management problems.

PubMed

Kotsanos, N; Coolidge, T; Velonis, D; Arapostathis, K N

2009-06-01

This paper reports on the use of early introduction of a specific parental presence/absence (PPA) behavioural technique to manage the initially uncooperative child. Using a prospective design, 440 healthy children aged 3 to 10 years visited a paediatric dental practice within 33 months. Children exhibiting initially Frankl 'negative' and 'definitely negative' behaviour were empathically offered parental presence only if they were cooperative. Otherwise, the parent stepped out until behaviour improvement. t-tests and Chi-square tests were used to compare characteristics of initially cooperative and uncooperative children, as well as proportions of parents who were asked to leave the surgery. The technique's success was assessed by a one sample binomial test. 75 of the children presented as Frankl either 'negative' (30) or 'definitely negative' (45) at their first visit; 70 (93.3%, p<0.001) responded to the PPA technique by displaying positive behaviour as their first visit progressed. 38 responded without the need to ask the parent to exit the practice room, while the other 32 responded only after their parent exited. 52 children had additional appointments, and 8 required an application of PPA at a second appointment; all children cooperated in all subsequent appointments. Early and empathic application of the PPA technique appears very successful in managing initially uncooperative child patients, suggesting that a randomised controlled trial of the technique is warranted.

Effective dynamical coupling of hydrodynamics and transport for heavy-ion collisions

NASA Astrophysics Data System (ADS)

Oliinychenko, Dmytro; Petersen, Hannah

2017-04-01

Present hydrodynamics-based simulations of heavy-ion collisions neglect the feedback from the frozen-out particles flying back into the hydrodynamical region. This causes an artefact called “negative Cooper-Frye contributions”, which is negligible for high collision energies, but becomes significant for lower RHIC BES energies and for event-by-event simulations. To avoid negative Cooper-Frye contributions, while still preserving hydrodynamical behavior, we propose a pure hadronic transport approach with forced thermalization in the regions of high energy density. It is demonstrated that this approach exhibits enhancement of strangeness and mean transverse momenta compared to conventional transport - an effect typical for hydrodynamical approaches.

A cellular automaton model for evacuation flow using game theory

NASA Astrophysics Data System (ADS)

Guan, Junbiao; Wang, Kaihua; Chen, Fangyue

2016-11-01

Game theory serves as a good tool to explore crowd dynamic conflicts during evacuation processes. The purpose of this study is to simulate the complicated interaction behavior among the conflicting pedestrians in an evacuation flow. Two types of pedestrians, namely, defectors and cooperators, are considered, and two important factors including fear index and cost coefficient are taken into account. By combining the snowdrift game theory with a cellular automaton (CA) model, it is shown that the increase of fear index and cost coefficient will lengthen the evacuation time, which is more apparent for large values of cost coefficient. Meanwhile, it is found that the defectors to cooperators ratio could always tend to consistent states despite different values of parameters, largely owing to self-organization effects.

The Intracellular Juxtamembrane Domain of the Epidermal Growth Factor (EGF) Receptor Is Responsible for the Allosteric Regulation of EGF Binding*S⃞♦

PubMed Central

Macdonald-Obermann, Jennifer L.; Pike, Linda J.

2009-01-01

We have previously shown that the binding of epidermal growth factor (EGF) to its receptor can best be described by a model that involves negative cooperativity in an aggregating system (Macdonald, J. L., and Pike, L. J. (2008) Proc. Natl. Acad. Sci. U. S. A. 105, 112–117). However, despite the fact that biochemical analyses indicate that EGF induces dimerization of its receptor, the binding data provided no evidence for positive linkage between EGF binding and dimer assembly. By analyzing the binding of EGF to a number of receptor mutants, we now report that in naive, unphosphorylated EGF receptors, ligand binding is positively linked to receptor dimerization but the linkage is abolished upon autophosphorylation of the receptor. Both phosphorylated and unphosphorylated EGF receptors exhibit negative cooperativity, indicating that mechanistically, cooperativity is distinct from the phenomenon of linkage. Nonetheless, both the positive linkage and the negative cooperativity observed in EGF binding require the presence of the intracellular juxtamembrane domain. This indicates the existence of inside-out signaling in the EGF receptor system. The intracellular juxtamembrane domain has previously been shown to be required for the activation of the EGF receptor tyrosine kinase (Thiel, K. W., and Carpenter, G. (2007) Proc. Natl. Acad. Sci. U. S. A. 104, 19238–19243). Our experiments expand the role of this domain to include the allosteric control of ligand binding by the extracellular domain. PMID:19336395

Social embeddedness and economic opportunism: a game situation.

PubMed

Sakalaki, Maria; Fousiani, Kyriaki

2012-06-01

According to Evolutionary Game Theory, multiple exchanges with partners are necessary to foster cooperation. Multiple exchanges with partners tend to enhance the good experience of the partners and the predictability of their behaviour and should therefore increase cooperativeness. This study explored whether social embeddedness, or the preference for close and stable social relationships, a variable which tends to increase multiple exchanges, is associated with more cooperative attitudes; and whether social embeddedness increases cooperative behavior towards unknown partners in a game situation. The first study, with 169 undergraduates, indicated that social embeddedness (preference for close and durable social relations) was negatively associated with opportunistic attitudes. The second study had a sample of 60 undergraduates playing a Trust Game with unknown partners and showed that self-reported social embeddedness was positively correlated with scores for cooperative economic behavior towards the partners. These results highlight the relationships of social embeddedness with cooperative attitudes and behaviour.

Effects of cooperative learning strategy on undergraduate kinesiology students' learning styles.

PubMed

Meeuwsen, Harry J; King, George A; Pederson, Rockie

2005-10-01

A growing body of research supports cooperative learning as an effective teaching strategy. A specific cooperative learning strategy, Team-based Learning, was applied to a convenience sample of four undergraduate sophomore-level motor behavior courses over four semesters from Fall 2002 to Spring 2004 to examine whether this strategy would affect students' learning styles. The data from the Grasha-Reichmann Student Learning Style Scales indicated that this teaching strategy was associated with a significant decrease in the negative Avoidant and Dependent learning styles and an improvement in the positive Participant learning style.

Detrimental effects of sanctions on human altruism.

PubMed

Fehr, Ernst; Rockenbach, Bettina

2003-03-13

The existence of cooperation and social order among genetically unrelated individuals is a fundamental problem in the behavioural sciences. The prevailing approaches in biology and economics view cooperation exclusively as self-interested behaviour--unrelated individuals cooperate only if they face economic rewards or sanctions rendering cooperation a self-interested choice. Whether economic incentives are perceived as just or legitimate does not matter in these theories. Fairness-based altruism is, however, a powerful source of human cooperation. Here we show experimentally that the prevailing self-interest approach has serious shortcomings because it overlooks negative effects of sanctions on human altruism. Sanctions revealing selfish or greedy intentions destroy altruistic cooperation almost completely, whereas sanctions perceived as fair leave altruism intact. These findings challenge proximate and ultimate theories of human cooperation that neglect the distinction between fair and unfair sanctions, and they are probably relevant in all domains in which voluntary compliance matters--in relations between spouses, in the education of children, in business relations and organizations as well as in markets.

[Infection control team (ICT) in cooperation with microbiology laboratories].

PubMed

Okazaki, Mitsuhiro

2012-10-01

Infection control as a medical safety measure is an important issue in all medical facilities. In order to tackle this measure, cooperation between the infection control team (ICT) and microbiological laboratory is indispensable. Multiple drug-resistant bacteria have shifted from Gram-positive bacteria to Gram-negative bacilli within the last ten years. There are also a variety of bacilli, complicating the examination method and test results further. Therefore, cooperation between the ICT and microbiological laboratory has become important to understand examination results and to use them. In order to maintain functional cooperation, explanatory and communicative ability between the microbiological laboratory and ICT is required every day. Such positive information exchange will develop into efficient and functional ICT activity.

How mutation alters the evolutionary dynamics of cooperation on networks

NASA Astrophysics Data System (ADS)

Ichinose, Genki; Satotani, Yoshiki; Sayama, Hiroki

2018-05-01

Cooperation is ubiquitous at every level of living organisms. It is known that spatial (network) structure is a viable mechanism for cooperation to evolve. A recently proposed numerical metric, average gradient of selection (AGoS), a useful tool for interpreting and visualizing evolutionary dynamics on networks, allows simulation results to be visualized on a one-dimensional phase space. However, stochastic mutation of strategies was not considered in the analysis of AGoS. Here we extend AGoS so that it can analyze the evolution of cooperation where mutation may alter strategies of individuals on networks. We show that our extended AGoS correctly visualizes the final states of cooperation with mutation in the individual-based simulations. Our analyses revealed that mutation always has a negative effect on the evolution of cooperation regardless of the payoff functions, fraction of cooperators, and network structures. Moreover, we found that scale-free networks are the most vulnerable to mutation and thus the dynamics of cooperation are altered from bistability to coexistence on those networks, undergoing an imperfect pitchfork bifurcation.

A test of evolutionary policing theory with data from human societies.

PubMed

Kümmerli, Rolf

2011-01-01

In social groups where relatedness among interacting individuals is low, cooperation can often only be maintained through mechanisms that repress competition among group members. Repression-of-competition mechanisms, such as policing and punishment, seem to be of particular importance in human societies, where cooperative interactions often occur among unrelated individuals. In line with this view, economic games have shown that the ability to punish defectors enforces cooperation among humans. Here, I examine a real-world example of a repression-of-competition system, the police institutions common to modern human societies. Specifically, I test evolutionary policing theory by comparing data on policing effort, per capita crime rate, and similarity (used as a proxy for genetic relatedness) among citizens across the 26 cantons of Switzerland. This comparison revealed full support for all three predictions of evolutionary policing theory. First, when controlling for policing efforts, crime rate correlated negatively with the similarity among citizens. This is in line with the prediction that high similarity results in higher levels of cooperative self-restraint (i.e. lower crime rates) because it aligns the interests of individuals. Second, policing effort correlated negatively with the similarity among citizens, supporting the prediction that more policing is required to enforce cooperation in low-similarity societies, where individuals' interests diverge most. Third, increased policing efforts were associated with reductions in crime rates, indicating that policing indeed enforces cooperation. These analyses strongly indicate that humans respond to cues of their social environment and adjust cheating and policing behaviour as predicted by evolutionary policing theory.

A Test of Evolutionary Policing Theory with Data from Human Societies

PubMed Central

Kümmerli, Rolf

2011-01-01

In social groups where relatedness among interacting individuals is low, cooperation can often only be maintained through mechanisms that repress competition among group members. Repression-of-competition mechanisms, such as policing and punishment, seem to be of particular importance in human societies, where cooperative interactions often occur among unrelated individuals. In line with this view, economic games have shown that the ability to punish defectors enforces cooperation among humans. Here, I examine a real-world example of a repression-of-competition system, the police institutions common to modern human societies. Specifically, I test evolutionary policing theory by comparing data on policing effort, per capita crime rate, and similarity (used as a proxy for genetic relatedness) among citizens across the 26 cantons of Switzerland. This comparison revealed full support for all three predictions of evolutionary policing theory. First, when controlling for policing efforts, crime rate correlated negatively with the similarity among citizens. This is in line with the prediction that high similarity results in higher levels of cooperative self-restraint (i.e. lower crime rates) because it aligns the interests of individuals. Second, policing effort correlated negatively with the similarity among citizens, supporting the prediction that more policing is required to enforce cooperation in low-similarity societies, where individuals' interests diverge most. Third, increased policing efforts were associated with reductions in crime rates, indicating that policing indeed enforces cooperation. These analyses strongly indicate that humans respond to cues of their social environment and adjust cheating and policing behaviour as predicted by evolutionary policing theory. PMID:21909429

Evidence for co-operativity in coenzyme binding to tetrameric Sulfolobus solfataricus alcohol dehydrogenase and its structural basis: fluorescence, kinetic and structural studies of the wild-type enzyme and non-co-operative N249Y mutant.

PubMed

Giordano, Antonietta; Febbraio, Ferdinando; Russo, Consiglia; Rossi, Mosè; Raia, Carlo A

2005-06-01

The interaction of coenzyme with thermostable homotetrameric NAD(H)-dependent alcohol dehydrogenase from the thermoacidophilic sulphur-dependent crenarchaeon Sulfolobus solfataricus (SsADH) and its N249Y (Asn-249-->Tyr) mutant was studied using the high fluorescence sensitivity of its tryptophan residues Trp-95 and Trp-117 to the binding of coenzyme moieties. Fluorescence quenching studies performed at 25 degrees C show that SsADH exhibits linearity in the NAD(H) binding [the Hill coefficient (h) approximately 1) at pH 9.8 and at moderate ionic strength, in addition to positive co-operativity (h=2.0-2.4) at pH 7.8 and 6.8, and at pH 9.8 in the presence of salt. Furthermore, NADH binding is positively co-operative below 20 degrees C (h approximately 3) and negatively co-operative at 40-50 degrees C (h approximately 0.7), as determined at moderate ionic strength and pH 9.8. Steady-state kinetic measurements show that SsADH displays standard Michaelis-Menten kinetics between 35 and 45 degrees C, but exhibits positive and negative co-operativity for NADH oxidation below (h=3.3 at 20 degrees C) and above (h=0.7 at 70-80 degrees C) this range of temperatures respectively. However, N249Y SsADH displays non-co-operative behaviour in coenzyme binding under the same experimental conditions used for the wild-type enzyme. In loop 270-275 of the coenzyme domain and segments at the interface of dimer A-B, analyses of the wild-type and mutant SsADH structures identified the structural elements involved in the intersubunit communication and suggested a possible structural basis for co-operativity. This is the first report of co-operativity in a tetrameric ADH and of temperature-induced co-operativity in a thermophilic enzyme.

Does plant apparency matter? Thirty years of data provide limited support but reveal clear patterns of the effects of plant chemistry on herbivores.

PubMed

Smilanich, Angela M; Fincher, R Malia; Dyer, Lee A

2016-05-01

According to the plant-apparency hypothesis, apparent plants allocate resources to quantitative defenses that negatively affect generalist and specialist herbivores, while unapparent plants invest more in qualitative defenses that negatively affect nonadapted generalists. Although this hypothesis has provided a useful framework for understanding the evolution of plant chemical defense, there are many inconsistencies surrounding associated predictions, and it has been heavily criticized and deemed obsolete. We used a hierarchical Bayesian meta-analysis model to test whether defenses from apparent and unapparent plants differ in their effects on herbivores. We collected a total of 225 effect sizes from 158 published papers in which the effects of plant chemistry on herbivore performance were reported. As predicted by the plant-apparency hypothesis, we found a prevalence of quantitative defenses in woody plants and qualitative defenses in herbaceous plants. However, the detrimental impacts of qualitative defenses were more effective against specialists than generalists, and the effects of chemical defenses did not significantly differ between specialists and generalists for woody or herbaceous plants. A striking pattern that emerged from our data was a pervasiveness of beneficial effects of secondary metabolites on herbivore performance, especially generalists. This pattern provides evidence that herbivores are evolving effective counteradaptations to putative plant defenses. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Apparent Diffusion Coefficient and Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Pancreatic Cancer: Characteristics and Correlation With Histopathologic Parameters.

PubMed

Ma, Wanling; Li, Na; Zhao, Weiwei; Ren, Jing; Wei, Mengqi; Yang, Yong; Wang, Yingmei; Fu, Xin; Zhang, Zhuoli; Larson, Andrew C; Huan, Yi

2016-01-01

To clarify diffusion and perfusion abnormalities and evaluate correlation between apparent diffusion coefficient (ADC), MR perfusion and histopathologic parameters of pancreatic cancer (PC). Eighteen patients with PC underwent diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Parameters of DCE-MRI and ADC of cancer and non-cancerous tissue were compared. Correlation between the rate constant that represents transfer of contrast agent from the arterial blood into the extravascular extracellular space (K, volume of the extravascular extracellular space per unit volume of tissue (Ve), and ADC of PC and histopathologic parameters were analyzed. The rate constant that represents transfer of contrast agent from the extravascular extracellular space into blood plasma, K, tissue volume fraction occupied by vascular space, and ADC of PC were significantly lower than nontumoral pancreases. Ve of PC was significantly higher than that of nontumoral pancreas. Apparent diffusion coefficient and K values of PC were negatively correlated to fibrosis content and fibroblast activation protein staining score. Fibrosis content was positively correlated to Ve. Apparent diffusion coefficient values and parameters of DCE-MRI can differentiate PC from nontumoral pancreases. There are correlations between ADC, K, Ve, and fibrosis content of PC. Fibroblast activation protein staining score of PC is negatively correlated to ADC and K. Apparent diffusion coefficient, K, and Ve may be feasible to predict prognosis of PC.

How much structuring is beneficial with regard to examination scores? A prospective study of three forms of active learning.

PubMed

Reinhardt, Claus H; Rosen, Evelyne N

2012-09-01

Many studies have demonstrated a superiority of active learning forms compared with traditional lecture. However, there is still debate as to what degree structuring is necessary with regard to high exam outcomes. Seventy-five students from a premedical school were randomly attributed to an active lecture group, a cooperative group, or a collaborative learning group. The active lecture group received lectures with questions to resolve at the end of the lecture. At the same time, the cooperative group and the collaborative group had to work on a problem and prepare presentations for their answers. The collaborative group worked in a mostly self-directed manner; the cooperative group had to follow a time schedule. For the additional work of preparing the poster presentation, the collaborative and cooperative groups were allowed 50% more working time. In part 1, all groups worked on the citric acid cycle, and in part 2, all groups worked on molecular genetics. Collaborative groups had to work on tasks and prepare presentations for their answers. At the end of each part, all three groups were subjected to the same exam. Additionally, in the collaborative and cooperative groups, the presentations were marked. All evaluations were performed by two independent examiners. Exam results of the active lecture groups were highest. Results of the cooperative group were nonsignificantly lower than the active lecture group and significantly higher than the collaborative group. The presentation quality was nonsignificantly higher in the collaborative group compared with the cooperative group. This study shows that active lecturing produced the highest exam results, which significantly differed from collaborative learning results. The additional elaboration in the cooperative and collaborative learning setting yielded the high presentation quality but apparently could not contribute further to exam scores. Cooperative learning seems to be a good compromise if high exam and presentation scores are expected.

Incidence and biomarkers of pregnancy, spontaneous abortion, and neonatal loss during an environmental stressor: Implications for female reproductive suppression in the cooperatively breeding meerkat.

PubMed

Dimac-Stohl, Kristin A; Davies, Charli S; Grebe, Nicholas M; Stonehill, Alexandra C; Greene, Lydia K; Mitchell, Jessica; Clutton-Brock, Tim; Drea, Christine M

2018-05-02

Meerkats are group-living, insectivorous herpestids in which subordinate members provide extensive care for the dominant female's young. In contrast to some cooperative breeders, subordinate female meerkats are physiologically able to reproduce and occasionally do so successfully; their attempts are more frequently 'suppressed' via eviction or infanticide by the dominant female. Spontaneous abortion and neonatal loss occur with some regularity, further negatively impacting reproductive success. Here, we compared the reproductive outcomes and endocrine profiles, including of serum progesterone (P 4 ), serum estradiol (E 2 ), and fecal glucocorticoid metabolites (fGCm), of dominant and subordinate dams residing within their clans in the Kalahari Desert of South Africa. Our study spanned years of drought, which reduced insect abundance and represented a substantial environmental stressor. Meerkat pregnancies were identified at mid-term and culminated either in spontaneous abortions or full-term deliveries, after which pups were either lost prior to emergence from the natal den (usually within 2days of birth) or emerged at 2-3weeks. Neonatal loss exceeded fetal loss for all females, and contributed to narrowing the status-related disparity in female reproductive output seen during less arid periods. Although E 2 concentrations were significantly lower in subordinate than dominant females, they were sufficient to support gestation. Absolute E 2 concentrations may owe to androgenic precursors that also attain highest concentrations in dominant dams and may mediate aggression underlying female reproductive skew. Pregnancies terminating in fetal loss were marked by significantly lower P 4 concentrations in mid-gestation and modestly lower E 2 concentrations overall. Consistently high fGCm concentrations further increased across trimesters, particularly (but not consistently) in subordinates and in aborted pregnancies. Environmental stressors may modulate reproductive outcomes in meerkats through their influence on sex steroids and their effects on intragroup competition. The social and eco-physiological factors affecting intraspecific variation in reproductive output, even in obligate cooperative breeders, may be most apparent during extreme conditions, reflecting the benefits of long-term studies for assessing the impact of climate change. Copyright © 2017 Elsevier Inc. All rights reserved.

Correlation of human papillomavirus status with apparent diffusion coefficient of diffusion-weighted MRI in head and neck squamous cell carcinomas.

PubMed

Driessen, Juliette P; van Bemmel, Alexander J M; van Kempen, Pauline M W; Janssen, Luuk M; Terhaard, Chris H J; Pameijer, Frank A; Willems, Stefan M; Stegeman, Inge; Grolman, Wilko; Philippens, Marielle E P

2016-04-01

Identification of prognostic patient characteristics in head and neck squamous cell carcinoma (HNSCC) is of great importance. Human papillomavirus (HPV)-positive HNSCCs have favorable response to (chemo)radiotherapy. Apparent diffusion coefficient, derived from diffusion-weighted MRI, has also shown to predict treatment response. The purpose of this study was to evaluate the correlation between HPV status and apparent diffusion coefficient. Seventy-three patients with histologically proven HNSCC were retrospectively analyzed. Mean pretreatment apparent diffusion coefficient was calculated by delineation of total tumor volume on diffusion-weighted MRI. HPV status was analyzed and correlated to apparent diffusion coefficient. Six HNSCCs were HPV-positive. HPV-positive HNSCC showed significantly lower apparent diffusion coefficient compared to HPV-negative. This correlation was independent of other patient characteristics. In HNSCC, positive HPV status correlates with low mean apparent diffusion coefficient. The favorable prognostic value of low pretreatment apparent diffusion coefficient might be partially attributed to patients with a positive HPV status. © 2015 Wiley Periodicals, Inc. Head Neck 38: E613-E618, 2016. © 2015 Wiley Periodicals, Inc.

Transient Cooperative Processes in Dewetting Polymer Melts.

PubMed

Chandran, Sivasurender; Reiter, Günter

2016-02-26

We compare the high velocity dewetting behavior, at elevated temperatures, of atactic polystyrene (aPS) and isotactic polystyrene (iPS) films, with the zero shear bulk viscosity (η_{bulk}) of aPS being approximately ten times larger than iPS. As expected, for aPS the apparent viscosity of the films (η_{f}) derived from high-shear dewetting is less than η_{bulk}, displaying a shear thinning behavior. Surprisingly, for iPS films, η_{f} is always larger than η_{bulk}, even at about 50 °C above the melting point, with η_{f}/η_{bulk} following an Arrhenius behavior. The corresponding activation energy of ∼160±10  kJ/mol for iPS films suggests a cooperative motion of segments which are aligned and agglomerated by fast dewetting.

When cooperation begets cooperation: the role of key individuals in galvanizing support.

PubMed

McAuliffe, Katherine; Wrangham, Richard; Glowacki, Luke; Russell, Andrew F

2015-12-05

Life abounds with examples of conspecifics actively cooperating to a common end, despite conflicts of interest being expected concerning how much each individual should contribute. Mathematical models typically find that such conflict can be resolved by partial-response strategies, leading investors to contribute relatively equitably. Using a case study approach, we show that such model expectations can be contradicted in at least four disparate contexts: (i) bi-parental care; (ii) cooperative breeding; (iii) cooperative hunting; and (iv) human cooperation. We highlight that: (a) marked variation in contributions is commonplace; and (b) individuals can often respond positively rather than negatively to the contributions of others. Existing models have surprisingly limited power in explaining these phenomena. Here, we propose that, although among-individual variation in cooperative contributions will be influenced by differential costs and benefits, there is likely to be a strong genetic or epigenetic component. We then suggest that selection can maintain high investors (key individuals) when their contributions promote support by increasing the benefits and/or reducing the costs for others. Our intentions are to raise awareness in--and provide testable hypotheses of--two of the most poorly understood, yet integral, questions regarding cooperative ventures: why do individuals vary in their contributions and when does cooperation beget cooperation? © 2015 The Author(s).

The Collective Benefits of Feeling Good and Letting Go: Positive Emotion and (dis)Inhibition Interact to Predict Cooperative Behavior

PubMed Central

Rand, David G.; Kraft-Todd, Gordon; Gruber, June

2015-01-01

Cooperation is central to human existence, forming the bedrock of everyday social relationships and larger societal structures. Thus, understanding the psychological underpinnings of cooperation is of both scientific and practical importance. Recent work using a dual-process framework suggests that intuitive processing can promote cooperation while deliberative processing can undermine it. Here we add to this line of research by more specifically identifying deliberative and intuitive processes that affect cooperation. To do so, we applied automated text analysis using the Linguistic Inquiry and Word Count (LIWC) software to investigate the association between behavior in one-shot anonymous economic cooperation games and the presence inhibition (a deliberative process) and positive emotion (an intuitive process) in free-response narratives written after (Study 1, N = 4,218) or during (Study 2, N = 236) the decision-making process. Consistent with previous results, across both studies inhibition predicted reduced cooperation while positive emotion predicted increased cooperation (even when controlling for negative emotion). Importantly, there was a significant interaction between positive emotion and inhibition, such that the most cooperative individuals had high positive emotion and low inhibition. This suggests that inhibition (i.e., reflective or deliberative processing) may undermine cooperative behavior by suppressing the prosocial effects of positive emotion. PMID:25625722

The collective benefits of feeling good and letting go: positive emotion and (dis)inhibition interact to predict cooperative behavior.

PubMed

Rand, David G; Kraft-Todd, Gordon; Gruber, June

2015-01-01

Cooperation is central to human existence, forming the bedrock of everyday social relationships and larger societal structures. Thus, understanding the psychological underpinnings of cooperation is of both scientific and practical importance. Recent work using a dual-process framework suggests that intuitive processing can promote cooperation while deliberative processing can undermine it. Here we add to this line of research by more specifically identifying deliberative and intuitive processes that affect cooperation. To do so, we applied automated text analysis using the Linguistic Inquiry and Word Count (LIWC) software to investigate the association between behavior in one-shot anonymous economic cooperation games and the presence inhibition (a deliberative process) and positive emotion (an intuitive process) in free-response narratives written after (Study 1, N = 4,218) or during (Study 2, N = 236) the decision-making process. Consistent with previous results, across both studies inhibition predicted reduced cooperation while positive emotion predicted increased cooperation (even when controlling for negative emotion). Importantly, there was a significant interaction between positive emotion and inhibition, such that the most cooperative individuals had high positive emotion and low inhibition. This suggests that inhibition (i.e., reflective or deliberative processing) may undermine cooperative behavior by suppressing the prosocial effects of positive emotion.

When cooperation begets cooperation: the role of key individuals in galvanizing support

PubMed Central

McAuliffe, Katherine; Wrangham, Richard; Glowacki, Luke; Russell, Andrew F.

2015-01-01

Life abounds with examples of conspecifics actively cooperating to a common end, despite conflicts of interest being expected concerning how much each individual should contribute. Mathematical models typically find that such conflict can be resolved by partial-response strategies, leading investors to contribute relatively equitably. Using a case study approach, we show that such model expectations can be contradicted in at least four disparate contexts: (i) bi-parental care; (ii) cooperative breeding; (iii) cooperative hunting; and (iv) human cooperation. We highlight that: (a) marked variation in contributions is commonplace; and (b) individuals can often respond positively rather than negatively to the contributions of others. Existing models have surprisingly limited power in explaining these phenomena. Here, we propose that, although among-individual variation in cooperative contributions will be influenced by differential costs and benefits, there is likely to be a strong genetic or epigenetic component. We then suggest that selection can maintain high investors (key individuals) when their contributions promote support by increasing the benefits and/or reducing the costs for others. Our intentions are to raise awareness in—and provide testable hypotheses of—two of the most poorly understood, yet integral, questions regarding cooperative ventures: why do individuals vary in their contributions and when does cooperation beget cooperation? PMID:26503685

Retrieval of charge mobility from apparent charge packet movements in LDPE thin films

NASA Astrophysics Data System (ADS)

Meng, Jia; Zhang, Yewen; Holé, Stéphane; Zheng, Feihu; An, Zhenlian

2017-03-01

The charge packet phenomenon observed in polyethylene materials has been reported extensively during the last decades. To explain its movement, Negative Differential Mobility (NDM) theory is a competitive model among several proposed mechanisms. However, as a key concept of this theory, a sufficiently acute relationship between charge mobility and electric field has never been reported until now, which makes it hard to precisely describe the migration of charge packets with this theory. Based on the substantial negative-charge packet observations with a sufficiently by wide electric field range from 15 kV/mm to 50 kV/mm, the present contribution successfully retrieved the negative-charge mobility from the apparent charge packet movements, which reveals a much closer relationship between the NDM theory and charge packet migrations. Back simulations of charge packets with the retrieved charge mobility offer a good agreement with the experimental data.

Dissolution of quartz in aqueous basic solution, 106-236 C - Surface kinetics of 'perfect' crystallographic faces

NASA Technical Reports Server (NTRS)

Gratz, Andrew J.; Bird, Peter; Quiro, Glenn B.

1990-01-01

A highly accurate method, called the negative crystal method, for determining the rate of dissolution on specific crystallographic faces of crystals was developed, in which the dissolution rates of nominally perfect crystal faces are obtained by measuring the size of individual negative crystals during a sequence of dissolution steps. The method was applied to determine the apparent activation energy and rate constants for the dissolution of quartz in 0.01 M KOH solutions at temperatures from 106 to 236 C. Also investigated were the effects of hydroxyl activity and ionic strength. The apparent activation energies for the dissolution of the prism and of the rhomb were determined.

The Enforcement of Moral Boundaries Promotes Cooperation and Prosocial Behavior in Groups

PubMed Central

Simpson, Brent; Willer, Robb; Harrell, Ashley

2017-01-01

The threat of free-riding makes the marshalling of cooperation from group members a fundamental challenge of social life. Where classical social science theory saw the enforcement of moral boundaries as a critical way by which group members regulate one another’s self-interest and build cooperation, moral judgments have most often been studied as processes internal to individuals. Here we investigate how the interpersonal expression of positive and negative moral judgments encourages cooperation in groups and prosocial behavior between group members. In a laboratory experiment, groups whose members could make moral judgments achieved greater cooperation than groups with no capacity to sanction, levels comparable to those of groups featuring costly material sanctions. In addition, members of moral judgment groups subsequently showed more interpersonal trust, trustworthiness, and generosity than all other groups. These findings extend prior work on peer enforcement, highlighting how the enforcement of moral boundaries offers an efficient solution to cooperation problems and promotes prosocial behavior between group members. PMID:28211503

The effect of wealth-based anti-expectation behaviors on public cooperation

NASA Astrophysics Data System (ADS)

Wang, Le; Chen, Tong; You, Xinshang; Wang, Yongjie

2018-03-01

Wealth difference is a common sense in our society. It is unreasonable to assume people have the same capability to donate money to the common pool in public goods game (PGG). Individuals have behavioral expectation towards their neighbors. In this paper, we introduce wealth-based anti-expectation mechanism to explore cooperation. Through numerical simulation results, we are glad to find that the anti-expectation mechanism could stimulate cooperation when the positive effects are equal to or larger than the negative effects from anti-expectation behaviors. Based on this mechanism, we propose propagation mechanism which aims to propagate the positive effects from the poor to inspire more people to choose cooperative strategies. When individuals are tolerant towards defectors, The fraction of cooperators increases with the increment of propagation distance. Enlarging the distance is not wise when individuals are harsh towards defectors. Additionally, we find that the more tolerant towards defectors we are, the higher the cooperation rate is in general. Therefore in PGG, we could consider one's anti-expectation towards others' behaviors and improve cooperation by propagating the poor's anti-expectation effects.

Sparse cliques trump scale-free networks in coordination and competition

PubMed Central

Gianetto, David A.; Heydari, Babak

2016-01-01

Cooperative behavior, a natural, pervasive and yet puzzling phenomenon, can be significantly enhanced by networks. Many studies have shown how global network characteristics affect cooperation; however, it is difficult to understand how this occurs based on global factors alone, low-level network building blocks, or motifs are necessary. In this work, we systematically alter the structure of scale-free and clique networks and show, through a stochastic evolutionary game theory model, that cooperation on cliques increases linearly with community motif count. We further show that, for reactive stochastic strategies, network modularity improves cooperation in the anti-coordination Snowdrift game and the Prisoner’s Dilemma game but not in the Stag Hunt coordination game. We also confirm the negative effect of the scale-free graph on cooperation when effective payoffs are used. On the flip side, clique graphs are highly cooperative across social environments. Adding cycles to the acyclic scale-free graph increases cooperation when multiple games are considered; however, cycles have the opposite effect on how forgiving agents are when playing the Prisoner’s Dilemma game. PMID:26899456

Sparse cliques trump scale-free networks in coordination and competition

NASA Astrophysics Data System (ADS)

Gianetto, David A.; Heydari, Babak

2016-02-01

Cooperative behavior, a natural, pervasive and yet puzzling phenomenon, can be significantly enhanced by networks. Many studies have shown how global network characteristics affect cooperation; however, it is difficult to understand how this occurs based on global factors alone, low-level network building blocks, or motifs are necessary. In this work, we systematically alter the structure of scale-free and clique networks and show, through a stochastic evolutionary game theory model, that cooperation on cliques increases linearly with community motif count. We further show that, for reactive stochastic strategies, network modularity improves cooperation in the anti-coordination Snowdrift game and the Prisoner’s Dilemma game but not in the Stag Hunt coordination game. We also confirm the negative effect of the scale-free graph on cooperation when effective payoffs are used. On the flip side, clique graphs are highly cooperative across social environments. Adding cycles to the acyclic scale-free graph increases cooperation when multiple games are considered; however, cycles have the opposite effect on how forgiving agents are when playing the Prisoner’s Dilemma game.

Selection methods regulate evolution of cooperation in digital evolution

PubMed Central

Lichocki, Paweł; Floreano, Dario; Keller, Laurent

2014-01-01

A key, yet often neglected, component of digital evolution and evolutionary models is the ‘selection method’ which assigns fitness (number of offspring) to individuals based on their performance scores (efficiency in performing tasks). Here, we study with formal analysis and numerical experiments the evolution of cooperation under the five most common selection methods (proportionate, rank, truncation-proportionate, truncation-uniform and tournament). We consider related individuals engaging in a Prisoner's Dilemma game where individuals can either cooperate or defect. A cooperator pays a cost, whereas its partner receives a benefit, which affect their performance scores. These performance scores are translated into fitness by one of the five selection methods. We show that cooperation is positively associated with the relatedness between individuals under all selection methods. By contrast, the change in the performance benefit of cooperation affects the populations’ average level of cooperation only under the proportionate methods. We also demonstrate that the truncation and tournament methods may introduce negative frequency-dependence and lead to the evolution of polymorphic populations. Using the example of the evolution of cooperation, we show that the choice of selection method, though it is often marginalized, can considerably affect the evolutionary dynamics. PMID:24152811

Dynamic instability of cooperation due to diverse activity patterns in evolutionary social dilemmas

NASA Astrophysics Data System (ADS)

Xia, Cheng-Yi; Meloni, Sandro; Perc, Matjaž; Moreno, Yamir

2015-03-01

Individuals might abstain from participating in an instance of an evolutionary game for various reasons, ranging from lack of interest to risk aversion. In order to understand the consequences of such diverse activity patterns on the evolution of cooperation, we study a weak prisoner's dilemma where each player's participation is probabilistic rather than certain. Players that do not participate get a null payoff and are unable to replicate. We show that inactivity introduces cascading failures of cooperation, which are particularly severe on scale-free networks with frequently inactive hubs. The drops in the fraction of cooperators are sudden, while the spatiotemporal reorganization of compact cooperative clusters, and thus the recovery, takes time. Nevertheless, if the activity of players is directly proportional to their degree, or if the interaction network is not strongly heterogeneous, the overall evolution of cooperation is not impaired. This is because inactivity negatively affects the potency of low-degree defectors, who are hence unable to utilize on their inherent evolutionary advantage. Between cascading failures, the fraction of cooperators is therefore higher than usual, which lastly balances out the asymmetric dynamic instabilities that emerge due to intermittent blackouts of cooperative hubs.

Cooperation in social dilemmas: free riding may be thwarted by second-order reward rather than by punishment.

PubMed

Kiyonari, Toko; Barclay, Pat

2008-10-01

Cooperation among nonrelatives can be puzzling because cooperation often involves incurring costs to confer benefits on unrelated others. Punishment of noncooperators can sustain otherwise fragile cooperation, but the provision of punishment suffers from a "second-order" free-riding problem because nonpunishers can free ride on the benefits from costly punishment provided by others. One suggested solution to this problem is second-order punishment of nonpunishers; more generally, the threat or promise of higher order sanctions might maintain the lower order sanctions that enforce cooperation in collective action problems. Here the authors report on 3 experiments testing people's willingness to provide second-order sanctions by having participants play a cooperative game with opportunities to punish and reward each other. The authors found that people supported those who rewarded cooperators either by rewarding them or by punishing nonrewarders, but people did not support those who punished noncooperators--they did not reward punishers or punish nonpunishers. Furthermore, people did not approve of punishers more than they did nonpunishers, even when nonpunishers were clearly unwilling to use sanctions to support cooperation. The results suggest that people will much more readily support positive sanctions than they will support negative sanctions.

Characterization of Actinides Complexed to Nuclear Fuel Constituents Using ESI-MS.

PubMed

McDonald, Luther W; Campbell, James A; Vercouter, Thomas; Clark, Sue B

2016-03-01

Electrospray ionization-mass spectrometry (ESI-MS) was tested for its use in monitoring spent nuclear fuel (SNF) constituents including U, Pu, dibutyl phosphate (DBP), and tributyl phosphate (TBP). Both positive and negative ion modes were used to evaluate the speciation of U and Pu with TBP and DBP. Furthermore, apparent stability constants were determined for U complexed to TBP and DBP. In positive ion mode, TBP produced a strong signal with and without complexation to U or Pu, but, in negative ion mode, no TBP, U-TBP, or Pu-TBP complexes were observed. Apparent stability constants were determined for [UO2(NO3)2(TBP)2], [UO2(NO3)2(H2O)(TBP)2], and [UO2(NO3)2(TBP)3]. In contrast DBP, U-DBP, and Pu-DBP complexes were observed in both positive and negative ion modes. Apparent stability constants were determined for the species [UO2(DBP)], [UO2(DBP)3], and [UO2(DBP)4]. Analyzing mixtures of U or Pu with TBP and DBP yielded the formation of ternary complexes whose stoichiometry was directly related to the ratio of TBP to DBP. The ESI-MS protocols used in this study will further demonstrate the utility of ESI-MS and its applicability to process control monitoring in SNF reprocessing facilities.

Buckling of Elastomeric Beams Enables Actuation of Soft Machines

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

Yang, Dian; Mosadegh, Bobak; Ainla, Alar

2015-09-21

Soft, pneumatic actuators that buckle when interior pressure is less than exterior provide a new mechanism of actuation. Upon application of negative pneumatic pressure, elastic beam elements in these actuators undergo reversible, cooperative collapse, and generate a rotational motion. These actuators are inexpensive to fabricate, lightweight, easy to control, and safe to operate. They can be used in devices that manipulate objects, locomote, or interact cooperatively with humans.

Cooperation predictors for dental patients with autism.

PubMed

Marshall, Jennifer; Sheller, Barbara; Williams, Bryan J; Mancl, Lloyd; Cowan, Charles

2007-01-01

This study evaluated potential predictors of cooperation during dental appointments for children with autism. Data were collected from 108 parent/child pairs and their dentists. Questions included: (1) medical/dental history; (2)functional language; (3) personal hygiene skills; (4) academic setting; and (5) achievements. Behavior was scored using the Frankl scale. Subjects were 80 males and 28 females 2.7 to 19 years old with a mean age of 9.8 years. Frankl scores were 65% uncooperative (definitely negative or negative) and 35% cooperative (positive or definitely positive). Multiple factors predicted uncooperative behavior: (1) appointment type (P=.03); (2) concurrent medical diagnoses (P=.04); (3) nonverbal/minimal or echololic language (P=.005); (4) inability to understand language appropriate for age (P=.02); (5) inability to follow multistep instructions (P=.04); (6) parents providing most/all tooth-brushing (P=.004); (7) partially or not toilet trained at 4+ years (P=.02); (8) inability to sit for a haircut (P=.01); (9) attending special education (P<.001); and (10) inability to read at 6+ years (P<.001). Five questions readily answered by a caregiver may indicate a child's cooperative potential. Preappointment inquiry about toilet training, toothbrushing, haircuts, academic achievement and language can give the dentist insight into the child's ability to respond positively to behavior guidance techniques based on communication.

Interference between wave modes may contribute to the apparent negative dispersion observed in cancellous bone

PubMed Central

Anderson, Christian C.; Marutyan, Karen R.; Holland, Mark R.; Wear, Keith A.; Miller, James G.

2008-01-01

Previous work has shown that ultrasonic waves propagating through cancellous bone often exhibit a linear-with-frequency attenuation coefficient, but a decrease in phase velocity with frequency (negative dispersion) that is inconsistent with the causality-imposed Kramers–Kronig relations. In the current study, interfering wave modes similar to those observed in bone are shown to potentially contribute to the observed negative dispersion. Biot theory, the modified Biot–Attenborogh model, and experimental results are used to aid in simulating multiple-mode wave propagation through cancellous bone. Simulations entail constructing individual wave modes exhibiting a positive dispersion using plausible velocities and amplitudes, and then summing the individual modes to create mixed-mode output wave forms. Results of the simulations indicate that mixed-mode wave forms can exhibit negative dispersion when analyzed conventionally under the assumption that only one wave is present, even when the individual interfering waves exhibit positive dispersions in accordance with the Kramers–Kronig relations. Furthermore, negative dispersion is observed when little or no visual evidence of interference exists in the time-domain data. Understanding the mechanisms responsible for the observed negative dispersion could aid in determining the true material properties of cancellous bone, as opposed to the apparent properties measured using conventional data analysis techniques. PMID:19045668

Reciprocity, culture and human cooperation: previous insights and a new cross-cultural experiment

PubMed Central

Gächter, Simon; Herrmann, Benedikt

2008-01-01

Understanding the proximate and ultimate sources of human cooperation is a fundamental issue in all behavioural sciences. In this paper, we review the experimental evidence on how people solve cooperation problems. Existing studies show without doubt that direct and indirect reciprocity are important determinants of successful cooperation. We also discuss the insights from a large literature on the role of peer punishment in sustaining cooperation. The experiments demonstrate that many people are ‘strong reciprocators’ who are willing to cooperate and punish others even if there are no gains from future cooperation or any other reputational gains. We document this in new one-shot experiments, which we conducted in four cities in Russia and Switzerland. Our cross-cultural approach allows us furthermore to investigate how the cultural background influences strong reciprocity. Our results show that culture has a strong influence on positive and in especially strong negative reciprocity. In particular, we find large cross-cultural differences in ‘antisocial punishment’ of pro-social cooperators. Further cross-cultural research and experiments involving different socio-demographic groups document that the antisocial punishment is much more widespread than previously assumed. Understanding antisocial punishment is an important task for future research because antisocial punishment is a strong inhibitor of cooperation. PMID:19073476

Reciprocity, culture and human cooperation: previous insights and a new cross-cultural experiment.

PubMed

Gächter, Simon; Herrmann, Benedikt

2009-03-27

Understanding the proximate and ultimate sources of human cooperation is a fundamental issue in all behavioural sciences. In this paper, we review the experimental evidence on how people solve cooperation problems. Existing studies show without doubt that direct and indirect reciprocity are important determinants of successful cooperation. We also discuss the insights from a large literature on the role of peer punishment in sustaining cooperation. The experiments demonstrate that many people are 'strong reciprocators' who are willing to cooperate and punish others even if there are no gains from future cooperation or any other reputational gains. We document this in new one-shot experiments, which we conducted in four cities in Russia and Switzerland. Our cross-cultural approach allows us furthermore to investigate how the cultural background influences strong reciprocity. Our results show that culture has a strong influence on positive and in especially strong negative reciprocity. In particular, we find large cross-cultural differences in 'antisocial punishment' of pro-social cooperators. Further cross-cultural research and experiments involving different socio-demographic groups document that the antisocial punishment is much more widespread than previously assumed. Understanding antisocial punishment is an important task for future research because antisocial punishment is a strong inhibitor of cooperation.

The zinc finger gene Xblimp1 controls anterior endomesodermal cell fate in Spemann's organizer.

PubMed Central

de Souza, F S; Gawantka, V; Gómez, A P; Delius, H; Ang, S L; Niehrs, C

1999-01-01

The anterior endomesoderm of the early Xenopus gastrula is a part of Spemann's organizer and is important for head induction. Here we describe Xblimp1, which encodes a zinc finger transcriptional repressor expressed in the anterior endomesoderm. Xblimp1 represses trunk mesoderm and induces anterior endomesoderm in a cooperative manner with the pan-endodermal gene Mix.1. Furthermore, Xblimp1 can cooperate with the BMP inhibitor chordin to induce ectopic heads, while a dominant-negative Xblimp1 inhibits head formation. The head inducer cerberus is positively regulated by Xblimp1 and is able to rescue microcephalic embryos caused by dominant-negative Xblimp1. Our results indicate that Xblimp1 is required for anterior endomesodermal cell fate and head induction. PMID:10545117

[Self-images and perceptions of other professions among students of nursing, physiotherapy, and occupational therapy and their importance for interprofessional cooperation].

PubMed

Boggatz, Thomas; Altmeppen, Sandra; Unger, Angelika

2010-07-01

Interdisciplinary cooperation is necessary to provide effective and high quality treatment for clients of the health care system. Interaction between professional groups depends on how their members perceive their self-image and the image of other professions. Within the framework of the project "Quality in the education of health-professionals" a qualitative study with 23 nurses, 24 physiotherapists and 15 occupational therapists in the second or third year of training was conducted. Participants were asked to report their self-image and the image of the other two professions. A qualitative content analysis according to Mayring was used for data analysis. Four categories emerged that allowed describing the self image and the image of the other professions: roles of the respective health professions, relation of the health professionals to their clients, attributes that typically characterized members of a particular profession, and relationship between the health professions. Latent conflicts between professional groups became apparent. Contradicting perceptions are due to subjective bias in favour of the own professional group. Interdisciplinary collaboration requires a new culture of co-operation.

How the initial level of visibility and limited resource affect the evolution of cooperation

NASA Astrophysics Data System (ADS)

Han, Dun; Li, Dandan; Sun, Mei

2016-06-01

This work sheds important light on how the initial level of visibility and limited resource might affect the evolution of the players’ strategies under different network structure. We perform the prisoner’s dilemma game in the lattice network and the scale-free network, the simulation results indicate that the average density of death in lattice network decreases with the increases of the initial proportion of visibility. However, the contrary phenomenon is observed in the scale-free network. Further results reflect that the individuals’ payoff in lattice network is significantly larger than the one in the scale-free network. In the lattice network, the visibility individuals could earn much more than the invisibility one. However, the difference is not apparent in the scale-free network. We also find that a high Successful-Defection-Payoff (SDB) and a rich natural environment have relatively larger deleterious cooperation effects. A high SDB is beneficial to raising the level of visibility in the heterogeneous network, however, that has adverse visibility consequences in homogeneous network. Our result reveals that players are more likely to cooperate voluntarily under homogeneous network structure.

Threshold-dependent cooperativity of Pdx1 and Oc1 in pancreatic progenitors establishes competency for endocrine differentiation and β-cell function

PubMed Central

Wright, Christopher V.E.; Won, Kyoung-Jae

2016-01-01

Summary Pdx1 and Oc1 are co-expressed in multipotent pancreatic progenitors and regulate the pro-endocrine gene Neurog3. Their expression diverges in later organogenesis, with Oc1 absent from hormone+ cells and Pdx1 maintained in mature β cells. In a classical genetic test for cooperative functional interactions, we derived mice with combined Pdx1 and Oc1 heterozygosity. Endocrine development in double-heterozygous pancreata was normal at embryonic day (e)13.5, but defects in specification and differentiation were apparent at e15.5, the height of the second wave of differentiation. Pancreata from double heterozygotes showed alterations in the expression of genes crucial for β-cell development and function, decreased numbers and altered allocation of Neurog3-expressing endocrine progenitors, and defective endocrine differentiation. Defects in islet gene expression and β-cell function persisted in double heterozygous neonates. These results suggest that Oc1 and Pdx1 cooperate prior to their divergence, in pancreatic progenitors, to allow for proper differentiation and functional maturation of β cells. PMID:27292642

COMT Val(108/158)Met polymorphism effects on emotional brain function and negativity bias.

PubMed

Williams, Leanne M; Gatt, Justine M; Grieve, Stuart M; Dobson-Stone, Carol; Paul, Robert H; Gordon, Evian; Schofield, Peter R

2010-11-15

Biases toward processing negative versus positive information vary as a function of level of awareness, and are modulated by monoamines. Excessive biases are associated with individual differences in mood and emotional stability, and emotional disorder. Here, we examined the impact of the catechol-O-methyltransferase (COMT) Val(108/158)Met polymorphism, involved in dopamine and norepinephrine catabolism, on both emotional brain function and self-reported negativity bias. COMT genotyping and self-reported level of negativity bias were completed for 46 healthy participants taking part in the Brain Resource International Database. Functional MRI was undertaken during perception of facial expressions of fear and happiness presented under unmasked (consciously identified) and masked (to prevent conscious detection) conditions. Structural MR images were also acquired. A greater number of COMT Met alleles predicted increased activation in brainstem, amygdala, basal ganglia and medial prefrontal regions for conscious fear, but decreased activation for conscious happiness. This pattern was also apparent for brainstem activation for the masked condition. Effects were most apparent for females. These differences could not be explained by gray matter variations. The Met-related profile of activation, particularly prefrontally, predicted greater negativity bias associated with risk for emotional disorder. The findings suggest that the COMT Met allele modulates neural substrates of negative versus positive emotion processing. This effect may contribute to negativity biases, which confer susceptibility for emotional disorders. Copyright 2010 Elsevier Inc. All rights reserved.

Relationships between cooperation and goal orientation among male professional and semi-professional team athletes.

PubMed

Lameiras, João; Almeida, Pedro L; Garcia-Mas, Alexandre

2014-12-01

In team sports, athletes' goals may focus on the task (enhancing performance, developing better skills, etc.) or on ego (being better than the others, achieving superiority, etc.). This study investigated the relationships between athletes' goal orientation and their tendency to cooperate with teammates and coaches. 158 professional men (M age = 24.1 yr., SD = 4.6) who played on various sport teams participated in this study. Goal orientation was measured with the Portuguese version of the Task and Ego Orientation in Sport Questionnaire, and cooperation was measured with the Questionário de Cooperação Desportiva. Cooperation was positively correlated with task orientation, and negatively correlated with ego orientation. Overall, the findings support that in sports, directing the players' focus on task may promote prosocial behavior.

Water as a Source of Cooperation or Conflict in the Middle East,

DTIC Science & Technology

1984-05-14

region. Shiite apprehension was increased in 1974 when it was rumored the Litani River would be diverted to Beirut to meet water shortages in the capital...The neglect of the agriculture of the south and the diver- sion rumors apparently contributed to the subsequent decision of the Shiites to form the...consolidated control of the Wazzani-Hasbani springs to increase water flow to the Jordan River; rumors of Israeli-imposed conservation measures were

BMI1 and H-RAS Cooperate to Drive Breast Cancer Metastasis | Center for Cancer Research

Cancer.gov

There have been significant improvements in the diagnosis of breast cancer at early stages of the disease. However, even when patients are identified early, there is a 30 percent chance of recurrence after apparently successful treatment of the initial tumor. The major cause of death for breast cancer patients is metastasis of the tumor to other organs but, unfortunately, the mechanisms of metastatic progression and cancer recurrence are poorly understood.

Apparent cooperativity of amino acid transport in Halobacterium halobium - Effect of electrical potential

NASA Technical Reports Server (NTRS)

Lanyi, J. K.

1978-01-01

Active serine accumulation in cell envelope vesicles from Halobacterium halobium proceeds by co-transport with Na(+) and can be induced by either transmembrane electrical potential or transmembrane Na(+) concentration difference. It was shown earlier that in the former case the initial transport rate is a fourth-power function of the magnitude of the electrochemical potential difference of sodium ions, and in the latter, a second-power function. A possible interpretation of this finding is cooperativity of sodium-transporting sites in the transport carrier. When both kinds of driving force are imposed simultaneously on the vesicles, fourth-power dependence on the total potential difference of sodium ions is obtained, suggesting that the transport carrier is regulated by the electrical potential. Heat treatment of the vesicles at 48 C partially inactivates transport and abolishes this effect of the electrical potential.

Development of U.S.-Russian medical support procedures for long-duration spaceflight: the NASA-Mir experience.

PubMed

Morgun, V V; Voronin, L I; Kaspranskiy, R R; Pool, S L; Barratt, M R; Navinkov, A L

2002-02-01

As the Russian Space Agency and the U.S. National Aeronautics and Space Administration began in the mid-1990s to plan a preliminary cooperative flight program in anticipation of the International Space Station, programmatic and philosophical differences became apparent in the technical and medical approaches of the two agencies. This paper briefly describes some of these differences and the process by which the two sides resolved differences in their approaches to the medical selection and certification of NASA-Mir crewmembers. These negotiations formed the basis for developing policies on other aspects of the medical support function for international missions, including crew training, preflight and postflight data collection, and rehabilitation protocols. The experience gained through this cooperative effort has been invaluable for developing medical care capabilities for the International Space Station.

Evidence for co-operativity in coenzyme binding to tetrameric Sulfolobus solfataricus alcohol dehydrogenase and its structural basis: fluorescence, kinetic and structural studies of the wild-type enzyme and non-co-operative N249Y mutant

PubMed Central

2005-01-01

The interaction of coenzyme with thermostable homotetrameric NAD(H)-dependent alcohol dehydrogenase from the thermoacidophilic sulphur-dependent crenarchaeon Sulfolobus solfataricus (SsADH) and its N249Y (Asn-249→Tyr) mutant was studied using the high fluorescence sensitivity of its tryptophan residues Trp-95 and Trp-117 to the binding of coenzyme moieties. Fluorescence quenching studies performed at 25 °C show that SsADH exhibits linearity in the NAD(H) binding [the Hill coefficient (h)∼1) at pH 9.8 and at moderate ionic strength, in addition to positive co-operativity (h=2.0–2.4) at pH 7.8 and 6.8, and at pH 9.8 in the presence of salt. Furthermore, NADH binding is positively co-operative below 20 °C (h∼3) and negatively co-operative at 40–50 °C (h∼0.7), as determined at moderate ionic strength and pH 9.8. Steady-state kinetic measurements show that SsADH displays standard Michaelis–Menten kinetics between 35 and 45 °C, but exhibits positive and negative co-operativity for NADH oxidation below (h=3.3 at 20 °C) and above (h=0.7 at 70–80 °C) this range of temperatures respectively. However, N249Y SsADH displays non-co-operative behaviour in coenzyme binding under the same experimental conditions used for the wild-type enzyme. In loop 270–275 of the coenzyme domain and segments at the interface of dimer A–B, analyses of the wild-type and mutant SsADH structures identified the structural elements involved in the intersubunit communication and suggested a possible structural basis for co-operativity. This is the first report of co-operativity in a tetrameric ADH and of temperature-induced co-operativity in a thermophilic enzyme. PMID:15651978

Temperament and self-based correlates of cooperative, competitive and individualistic learning preferences.

PubMed

Gocłowska, Małgorzata A; Aldhobaiban, Nawal; Elliot, Andrew J; Murayama, Kou; Kobeisy, Ahmed; Abdelaziz, Ashraf

2017-06-01

People vary in the extent to which they prefer cooperative, competitive or individualistic achievement tasks. In this research, we conducted two studies designed to investigate correlates and possible roots of these social interdependence orientations, namely approach and avoidance temperament, general self-efficacy, implicit theories of intelligence, and contingencies of self-worth based in others' approval, competition and academic competence. The results indicated that approach temperament, general self-efficacy and incremental theory were positively related, and entity theory was negatively related to cooperative preferences (|r| range from .11 to .41); approach temperament, general self-efficacy, competition contingencies and academic competence contingencies were positively related to competitive preferences (|r| range from .16 to .46); and avoidance temperament, entity theory, competitive contingencies and academic competence contingencies were positively related, and incremental theory was negatively related to individualistic preferences (|r| range from .09 to .15). The findings are discussed with regard to the meaning of each of the three social interdependence orientations, cultural differences among the observed relations and implications for practitioners. © 2015 International Union of Psychological Science.

Structural Basis for a Reciprocating Mechanism of Negative Cooperativity in Dimeric Phosphagen Kinase Activity

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

Wu, X.; Ye, S; Guo, S

Phosphagen kinase (PK) family members catalyze the reversible phosphoryl transfer between phosphagen and ADP to reserve or release energy in cell energy metabolism. The structures of classic quaternary complexes of dimeric creatine kinase (CK) revealed asymmetric ligand binding states of two protomers, but the significance and mechanism remain unclear. To understand this negative cooperativity further, we determined the first structure of dimeric arginine kinase (dAK), another PK family member, at 1.75 {angstrom}, as well as the structure of its ternary complex with AMPPNP and arginine. Further structural analysis shows that the ligand-free protomer in a ligand-bound dimer opens more widelymore » than the protomers in a ligand-free dimer, which leads to three different states of a dAK protomer. The unexpected allostery of the ligand-free protomer in a ligand-bound dimer should be relayed from the ligand-binding-induced allostery of its adjacent protomer. Mutations that weaken the interprotomer connections dramatically reduced the catalytic activities of dAK, indicating the importance of the allosteric propagation mediated by the homodimer interface. These results suggest a reciprocating mechanism of dimeric PK, which is shared by other ATP related oligomeric enzymes, e.g., ATP synthase. - Wu, X., Ye, S., Guo, S., Yan, W., Bartlam, M., Rao, Z. Structural basis for a reciprocating mechanism of negative cooperativity in dimeric phosphagen kinase activity.« less

A multilevel cross-cultural examination of role overload and organizational commitment: investigating the interactive effects of context.

PubMed

Fisher, David M

2014-07-01

Considering the influential nature of context, the current investigation examined whether the relationship between role overload and organizational commitment was affected by various contextual factors. Drawing on the occupational stress literature, structural empowerment and cooperative climate were examined as factors that would mitigate the negative effects of role overload on organizational commitment. In addition, national culture was examined to determine whether empowerment and cooperative climate had consistent moderating effects across cultures. The relationships among these variables were examined using hierarchical linear modeling in a sample of 6,264 employees working at a multinational organization in 337 different work locations across 18 countries. Results suggested that the negative effect of role overload on organizational commitment did not vary as a function of culture in the current sample, but empowerment and cooperative climate had a moderating influence on this relationship. Furthermore, a 3-way interaction was observed between the cultural variable of power distance, empowerment, and role overload in predicting organizational commitment, suggesting that factors that serve to mitigate the negative effects of role overload in one culture may be ineffectual in another. This 3-way interaction was observed regardless of whether Hofstede's (2001) cultural value indices were used or the cultural practice scores from the Global Leadership and Organizational Behavior Effectiveness (GLOBE) project (R. J. House, Hanges, Javidan, Dorfman, & Gupta, 2004).

Economic and cultural correlates of subjective wellbeing in countries using data from the Organisation for Economic Co-Operation and Development (OECD).

PubMed

Gaygisiz, Esma

2010-06-01

The correlations among indicators of objective well-being, cultural dimensions, and subjective well-being were investigated using Organisation for Economic Co-operation and Development (OECD) data from 35 countries. The subjective well-being measures included life satisfaction as well as six positive and six negative indexes of experience. Positive and negative experience scores were subjected to principal component analysis, and two positive experience components (labeled as "positive experiences" and "time management") and two negative experience components (labeled as "pain, worry, and sadness" and "anger and boredom") were extracted. Objective well-being included economic indicators, education, and health. The cultural variables included Hofstede's and Schwartz's cultural dimensions, national Big Five personality scores, and national IQs. High life satisfaction was positively related to Gross Domestic Product, life expectancy, education, individualism, affective and intellectual autonomy, egalitarianism, and conscientiousness, whereas low life satisfaction was related to unemployment, unequal income distribution, power distance, masculinity uncertainty avoidance, embeddedness, hierarchy, and neuroticism.

Correspondence between mothers' self-reported and observed child-rearing practices.

PubMed

Kochanska, G; Kuczynski, L; Radke-Yarrow, M

1989-02-01

The correspondence between self-reported child-rearing attitudes and practices and actual child management was examined among 68 mothers of young children. Data on mothers' verbal and physical control techniques along with children's responses (cooperation vs. resistance) were obtained during 90 min of spontaneous interaction in a naturalistic setting. Self-report data (the Block Q-Sort) were obtained 1-2 weeks later. The Block Q-Sort factors were combined to represent authoritarian and authoritative patterns of attitudes. The authoritarian pattern was positively associated with the use of direct commands, physical enforcements, reprimands, and prohibitive interventions, and negatively associated with the use of suggestions. The authoritative pattern was positively related to the use of suggestions and positive incentives, and negatively related to the use of physical enforcements, prohibitive interventions, and direct commands. Mothers' enjoyment of the parental role and their negative affect toward the child, as expressed in the Block Q-Sort, were more a result of the child's cooperation/resistance during the interaction than predictors of maternal control strategies.

Evolution of cooperation under social pressure in multiplex networks

NASA Astrophysics Data System (ADS)

Pereda, María

2016-09-01

In this work, we aim to contribute to the understanding of human prosocial behavior by studying the influence that a particular form of social pressure, "being watched," has on the evolution of cooperative behavior. We study how cooperation emerges in multiplex complex topologies by analyzing a particular bidirectionally coupled dynamics on top of a two-layer multiplex network (duplex). The coupled dynamics appears between the prisoner's dilemma game in a network and a threshold cascade model in the other. The threshold model is intended to abstract the behavior of a network of vigilant nodes that impose the pressure of being observed altering hence the temptation to defect of the dilemma. Cooperation or defection in the game also affects the state of a node of being vigilant. We analyze these processes on different duplex networks structures and assess the influence of the topology, average degree and correlated multiplexity, on the outcome of cooperation. Interestingly, we find that the social pressure of vigilance may impact cooperation positively or negatively, depending on the duplex structure, specifically the degree correlations between layers is determinant. Our results give further quantitative insights in the promotion of cooperation under social pressure.

Adolescents' responses to marital conflict: The role of cooperative marital conflict.

PubMed

Zhou, Nan; Buehler, Cheryl

2017-10-01

Not all youth exposed to hostile marital interactions develop negative responses to marital conflict. Cooperative marital conflict has long been considered as an important way of managing conflict and may serve as an important context in which hostility might convey during marital interactions. In light of little prior attention placed on the positive side of conflict processes, the main and moderating effects of cooperative marital conflict on youth responses to marital conflict were examined in a sample of 416 2-parent families using a multimethod, 2-year prospective design. Cooperative marital conflict was associated with decreases in youth emotional dysregulation, perceived threat, and behavioral dysregulation, and increases in constructive family representations and coping efficacy. As a specific dimension of cooperation, effective conflict resolution was associated uniquely with elevated youth coping efficacy, and decreased emotional and behavioral dysregulation; marital warmth was associated uniquely with increased constructive family representations. Significant interactions between marital hostility and marital cooperation also were found. These findings highlight the importance of examining cooperation above and beyond hostility in studies of marital conflict in order to better understand youth development during early adolescence. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

The evolution of cooperation within the gut microbiota.

PubMed

Rakoff-Nahoum, Seth; Foster, Kevin R; Comstock, Laurie E

2016-05-12

Cooperative phenotypes are considered central to the functioning of microbial communities in many contexts, including communication via quorum sensing, biofilm formation, antibiotic resistance, and pathogenesis. The human intestine houses a dense and diverse microbial community critical to health, yet we know little about cooperation within this important ecosystem. Here we test experimentally for evolved cooperation within the Bacteroidales, the dominant Gram-negative bacteria of the human intestine. We show that during growth on certain dietary polysaccharides, the model member Bacteroides thetaiotaomicron exhibits only limited cooperation. Although this organism digests these polysaccharides extracellularly, mutants lacking this ability are outcompeted. In contrast, we discovered a dedicated cross-feeding enzyme system in the prominent gut symbiont Bacteroides ovatus, which digests polysaccharide at a cost to itself but at a benefit to another species. Using in vitro systems and gnotobiotic mouse colonization models, we find that extracellular digestion of inulin increases the fitness of B. ovatus owing to reciprocal benefits when it feeds other gut species such as Bacteroides vulgatus. This is a rare example of naturally-evolved cooperation between microbial species. Our study reveals both the complexity and importance of cooperative phenotypes within the mammalian intestinal microbiota.

Cooperation and selfishness both occur during molecular evolution.

PubMed

Penny, David

2014-11-26

Perhaps the 'selfish' aspect of evolution has been over-emphasised, and organisms considered as basically selfish. However, at the macromolecular level of genes and proteins the cooperative aspect of evolution is more obvious and balances this self-centred aspect. Thousands of proteins must function together in an integrated manner to use and to produce the many molecules necessary for a functioning cell. The macromolecules have no idea whether they are functioning cooperatively or competitively with other genes and gene products (such as proteins). The cell is a giant cooperative system of thousands of genes/proteins that function together, even if it has to simultaneously resist 'parasites'. There are extensive examples of cooperative behavior among genes and proteins in both functioning cells and in the origin of life, so this cooperative nature, along with selfishness, must be considered part of normal evolution. The principles also apply to very large numbers of examples of 'positive interactions' between organisms, including both eukaryotes and akaryotes (prokaryotes). This does not negate in any way the 'selfishness' of genes - but macromolecules have no idea when they are helping, or hindering, other groups of macromolecules. We need to assert more strongly that genes, and gene products, function together as a cooperative unit.

Evolution of cooperation under social pressure in multiplex networks.

PubMed

Pereda, María

2016-09-01

In this work, we aim to contribute to the understanding of human prosocial behavior by studying the influence that a particular form of social pressure, "being watched," has on the evolution of cooperative behavior. We study how cooperation emerges in multiplex complex topologies by analyzing a particular bidirectionally coupled dynamics on top of a two-layer multiplex network (duplex). The coupled dynamics appears between the prisoner's dilemma game in a network and a threshold cascade model in the other. The threshold model is intended to abstract the behavior of a network of vigilant nodes that impose the pressure of being observed altering hence the temptation to defect of the dilemma. Cooperation or defection in the game also affects the state of a node of being vigilant. We analyze these processes on different duplex networks structures and assess the influence of the topology, average degree and correlated multiplexity, on the outcome of cooperation. Interestingly, we find that the social pressure of vigilance may impact cooperation positively or negatively, depending on the duplex structure, specifically the degree correlations between layers is determinant. Our results give further quantitative insights in the promotion of cooperation under social pressure.

When do people cooperate? The neuroeconomics of prosocial decision making.

PubMed

Declerck, Carolyn H; Boone, Christophe; Emonds, Griet

2013-02-01

Understanding the roots of prosocial behavior is an interdisciplinary research endeavor that has generated an abundance of empirical data across many disciplines. This review integrates research findings from different fields into a novel theoretical framework that can account for when prosocial behavior is likely to occur. Specifically, we propose that the motivation to cooperate (or not), generated by the reward system in the brain (extending from the striatum to the ventromedial prefrontal cortex), is modulated by two neural networks: a cognitive control system (centered on the lateral prefrontal cortex) that processes extrinsic cooperative incentives, and/or a social cognition system (including the temporo-parietal junction, the medial prefrontal cortex and the amygdala) that processes trust and/or threat signals. The independent modulatory influence of incentives and trust on the decision to cooperate is substantiated by a growing body of neuroimaging data and reconciles the apparent paradox between economic versus social rationality in the literature, suggesting that we are in fact wired for both. Furthermore, the theoretical framework can account for substantial behavioral heterogeneity in prosocial behavior. Based on the existing data, we postulate that self-regarding individuals (who are more likely to adopt an economically rational strategy) are more responsive to extrinsic cooperative incentives and therefore rely relatively more on cognitive control to make (un)cooperative decisions, whereas other-regarding individuals (who are more likely to adopt a socially rational strategy) are more sensitive to trust signals to avoid betrayal and recruit relatively more brain activity in the social cognition system. Several additional hypotheses with respect to the neural roots of social preferences are derived from the model and suggested for future research. Copyright © 2012 Elsevier Inc. All rights reserved.

When punishment pays.

PubMed

Roberts, Gilbert

2013-01-01

Explaining cooperation in groups remains a key problem because reciprocity breaks down between more than two. Punishing individuals who contribute little provides a potential answer but changes the dilemma to why pay the costs of punishing which, like cooperation itself, provides a public good. Nevertheless, people are observed to punish others in behavioural economic games, posing a problem for existing theory which highlights the difficulty in explaining the spread and persistence of punishment. Here, I consider the apparent mismatch between theory and evidence and show by means of instructive analysis and simulation how much of the experimental evidence for punishment comes from scenarios in which punishers may expect to obtain a net benefit from punishing free-riders. In repeated games within groups, punishment works by imposing costs on defectors so that it pays them to switch to cooperating. Both punishers and non-punishers then benefit from the resulting increase in cooperation, hence investing in punishment can constitute a social dilemma. However, I show the conditions in which the benefits of increased cooperation are so great that they more than offset the costs of punishing, thereby removing the temptation to free-ride on others' investments and making punishment explicable in terms of direct self-interest. Crucially, this is because of the leveraging effect imposed in typical studies whereby people can pay a small cost to inflict a heavy loss on a punished individual. In contrast to previous models suggesting punishment is disadvantaged when rare, I show it can invade until it comes into a producer-scrounger equilibrium with non-punishers. I conclude that adding punishment to an iterated public goods game can solve the problem of achieving cooperation by removing the social dilemma.

When Punishment Pays

PubMed Central

Roberts, Gilbert

2013-01-01

Explaining cooperation in groups remains a key problem because reciprocity breaks down between more than two. Punishing individuals who contribute little provides a potential answer but changes the dilemma to why pay the costs of punishing which, like cooperation itself, provides a public good. Nevertheless, people are observed to punish others in behavioural economic games, posing a problem for existing theory which highlights the difficulty in explaining the spread and persistence of punishment. Here, I consider the apparent mismatch between theory and evidence and show by means of instructive analysis and simulation how much of the experimental evidence for punishment comes from scenarios in which punishers may expect to obtain a net benefit from punishing free-riders. In repeated games within groups, punishment works by imposing costs on defectors so that it pays them to switch to cooperating. Both punishers and non-punishers then benefit from the resulting increase in cooperation, hence investing in punishment can constitute a social dilemma. However, I show the conditions in which the benefits of increased cooperation are so great that they more than offset the costs of punishing, thereby removing the temptation to free-ride on others' investments and making punishment explicable in terms of direct self-interest. Crucially, this is because of the leveraging effect imposed in typical studies whereby people can pay a small cost to inflict a heavy loss on a punished individual. In contrast to previous models suggesting punishment is disadvantaged when rare, I show it can invade until it comes into a producer-scrounger equilibrium with non-punishers. I conclude that adding punishment to an iterated public goods game can solve the problem of achieving cooperation by removing the social dilemma. PMID:23483907

Gender Differences in Emotional Responses to Cooperative and Competitive Game Play

PubMed Central

Kivikangas, J. Matias; Kätsyri, Jari; Järvelä, Simo; Ravaja, Niklas

2014-01-01

Previous research indicates that males prefer competition over cooperation, and it is sometimes suggested that females show the opposite behavioral preference. In the present article, we investigate the emotions behind the preferences: Do males exhibit more positive emotions during competitive than cooperative activities, and do females show the opposite pattern? We conducted two experiments where we assessed the emotional responses of same-gender dyads (in total 130 participants, 50 female) during intrinsically motivating competitive and cooperative digital game play using facial electromyography (EMG), skin conductance, heart rate measures, and self-reported emotional experiences. We found higher positive emotional responses (as indexed by both physiological measures and self-reports) during competitive than cooperative play for males, but no differences for females. In addition, we found no differences in negative emotions, and heart rate, skin conductance, and self-reports yielded contradictory evidence for arousal. These results support the hypothesis that males not only prefer competitive over cooperative play, but they also exhibit more positive emotional responses during them. In contrast, the results suggest that the emotional experiences of females do not differ between cooperation and competition, which implies that less competitiveness does not mean more cooperativeness. Our results pertain to intrinsically motivated game play, but might be relevant also for other kinds of activities. PMID:24983952

Impulsiveness does not prevent cooperation from emerging but reduces its occurrence: an experiment with zebra finches.

PubMed

Chia, Camille; Dubois, Frédérique

2017-08-17

Reciprocal altruism, the most probable mechanism for cooperation among unrelated individuals, can be modelled as a Prisoner's Dilemma. This game predicts that cooperation should evolve whenever the players, who expect to interact repeatedly, make choices contingent to their partner's behaviour. Experimental evidence, however, indicates that reciprocity is rare among animals. One reason for this would be that animals are very impulsive compared to humans. Several studies have reported that temporal discounting (that is, strong preferences for immediate benefits) has indeed a negative impact on the occurrence of cooperation. Yet, the role of impulsive action, another facet of impulsiveness, remains unexplored. Here, we conducted a laboratory experiment in which male and female zebra finches (Taenyopigia guttata) were paired assortatively with respect to their level of impulsive action and then played an alternating Prisoner's Dilemma. As anticipated, we found that self-controlled pairs achieved high levels of cooperation by using a Generous Tit-for-Tat strategy, while impulsive birds that cooperated at a lower level, chose to cooperate with a fixed probability. If the inability of impulsive individuals to use reactive strategies are due to their reduced working memory capacity, thus our findings might contribute to explaining interspecific differences in cooperative behaviour.

Gender differences in emotional responses to cooperative and competitive game play.

PubMed

Kivikangas, J Matias; Kätsyri, Jari; Järvelä, Simo; Ravaja, Niklas

2014-01-01

Previous research indicates that males prefer competition over cooperation, and it is sometimes suggested that females show the opposite behavioral preference. In the present article, we investigate the emotions behind the preferences: Do males exhibit more positive emotions during competitive than cooperative activities, and do females show the opposite pattern? We conducted two experiments where we assessed the emotional responses of same-gender dyads (in total 130 participants, 50 female) during intrinsically motivating competitive and cooperative digital game play using facial electromyography (EMG), skin conductance, heart rate measures, and self-reported emotional experiences. We found higher positive emotional responses (as indexed by both physiological measures and self-reports) during competitive than cooperative play for males, but no differences for females. In addition, we found no differences in negative emotions, and heart rate, skin conductance, and self-reports yielded contradictory evidence for arousal. These results support the hypothesis that males not only prefer competitive over cooperative play, but they also exhibit more positive emotional responses during them. In contrast, the results suggest that the emotional experiences of females do not differ between cooperation and competition, which implies that less competitiveness does not mean more cooperativeness. Our results pertain to intrinsically motivated game play, but might be relevant also for other kinds of activities.

Negative heterosis not apparent in 22-year-old hybrids of Picea mariana and Picea rubens

Treesearch

Kurt H. Johnsen; John E. Major; Judy Loo; Donald McPhee

1998-01-01

Abstract: Work from the 1970s indicated that, relative to either parent species, crosses between red spruce (Picea rubens Sarg.) and black spruce (Picea mariana (Mill.) B.S.P.) were inferior with respect to both growth and photosynthesis. We re-examined the hypothesis that there is negative heterosis in hybrids...

Heterogeneity and Cooperation: The Role of Capability and Valuation on Public Goods Provision

PubMed Central

Kolle, Felix

2018-01-01

We experimentally investigate the effects of two different sources of heterogeneity - capability and valuation - on the provision public goods when punishment is possible or not. We find that compared to homogeneous groups, asymmetric valuations for the public good have negative effects on cooperation and its enforcement through informal sanctions. Asymmetric capabilities in providing the public good, in contrast, have a positive and stabilizing effect on voluntary contributions. The main reason for these results are the different externalities contributions have on the other group members’ payoffs affecting individuals’ willingness to cooperate. We thus provide evidence that it is not the asymmetric nature of groups per se that facilitates or impedes collective action, but that it is rather the nature of asymmetry that determines the degree of cooperation and the level of public good provision. PMID:29367794

Battling the hematological malignancies: the 200 years' war.

PubMed

Lichtman, Marshall A

2008-02-01

The delineation of the hematological malignancies began near the end of the first third of the 19th century with the recognition of the similarity among cases with lymph node tumors and an enlarged spleen (Hodgkin's disease). Descriptions of chronic and acute leukemia and myeloma followed thereafter. In the first years of the 20th century the discovery of x-radiation permitted palliative orthovoltage radiation therapy of Hodgkin's disease. Following World War II, legitimate drug therapy for the hematological malignancies was introduced: nitrogen mustard, adrenocorticotropic hormone and cortisone acetate, and anti-folic acid derivatives, initially aminopterin. Today, about 14 classes of drugs (different mechanisms of action) and >50 individual agents are being used, with others under study. Several examples of agents targeting specific transcription factors or oncoproteins have been introduced. Despite remarkable progress, including the ability to cure acute leukemia in about 70% of children, cure several genetic variants of acute myelogenous leukemia in younger adults, cure some cases of lymphoma in children and younger adults, and induce prolonged remission in many affected persons, the majority of patients face an uncertain outcome and shortened life. Thus, we have much to do in the next several decades. The significant hurdles we must overcome include: the apparent infrequency of an exogenous cause that can be avoided, the exponential increase in incidence rates with age and the dramatic negative effect of aging on the results of treatment, the challenge of one trillion or more disseminated cancer cells among which are a smaller population of cancer stem cells, the profound genetic diversity of the hematological malignancies (apparently hundreds of unique genetic primary lesions), the redundant growth and survival pathways defining the cancer phenotype, the decreasing market for pharmaceutical companies as therapy becomes more specific (fewer target patients) and drug development costs become more expensive, and the significant negative long-term effects of current therapy on both children and adults. These challenges will be gradually overcome, if we (a) develop new models of cooperation among academia, industry, and government, (b) continue the growth of international participation in cancer research (more keen minds to the task), and (c) convince the governments of the world, including that of the U.S., that an investment in minimizing the effects of cancer is as important as defending against other threats to the welfare and longevity of their citizens.

Political skill: A proactive inhibitor of workplace aggression exposure and an active buffer of the aggression-strain relationship.

PubMed

Zhou, Zhiqing E; Yang, Liu-Qin; Spector, Paul E

2015-10-01

In the current study we examined the role of 4 dimensions of political skill (social astuteness, interpersonal influence, networking ability, and apparent sincerity) in predicting subsequent workplace aggression exposure based on the proactive coping framework. Further, we investigated their buffering effects on the negative outcomes of experienced workplace aggression based on the transactional stress model. Data were collected from nurses at 3 time points: before graduation (Time 1, n = 346), approximately 6 months after graduation (Time 2, n = 214), and approximately 12 months after graduation (Time 3, n = 161). Results showed that Time 1 interpersonal influence and apparent sincerity predicted subsequent physical aggression exposure. Exposure to physical and/or psychological workplace aggression was related to increased anger and musculoskeletal injury, and decreased job satisfaction and career commitment. Further, all dimensions of political skill but networking ability buffered some negative effects of physical aggression, and all dimensions but social astuteness buffered some negative effects of psychological aggression. (c) 2015 APA, all rights reserved).

Characterization of Actinides Complexed to Nuclear Fuel Constituents Using ESI-MS

DOE PAGES

McDonald, Luther W.; Campbell, James A.; Vercouter, Thomas; ...

2016-03-01

Electrospray ionization-mass spectrometry (ESI-MS) was tested for its use in monitoring spent nuclear fuel (SNF) constituents including U, Pu, dibutyl phosphate (DBP), and tributyl phosphate (TBP). Both positive and negative ion modes were used to evaluate the speciation of U and Pu with TBP and DBP. Furthermore, apparent stability constants were determined for U complexed to TBP and DBP. In positive ion mode, TBP produced a strong signal with and without complexation to U or Pu, but, in negative ion mode, no TBP, U-TBP, or Pu-TBP complexes were observed. Apparent stability constants were determined for [UO 2(NO 3) 2(TBP) 2],more » [UO 2(NO 3) 2(H 2O)(TBP) 2], and [UO 2(NO 3) 2(TBP) 3]. In contrast DBP, U-DBP, and Pu-DBP complexes were observed in both positive and negative ion modes. Apparent stability constants were determined for the species [UO 2(DBP)], [UO 2(DBP) 3], and [UO 2(DBP) 4]. Analyzing mixtures of U or Pu with TBP and DBP yielded the formation of ternary complexes whose stoichiometry was directly related to the ratio of TBP to DBP. The ESI-MS protocols used in this study will further demonstrate the utility of ESI-MS and its applicability to process control monitoring in SNF reprocessing facilities.« less

Do grandparents compete with or support their grandchildren? In Guatemala, paternal grandmothers may compete, and maternal grandmothers may cooperate.

PubMed

Sheppard, Paula; Sear, Rebecca

2016-04-01

Previous research has found that the presence of grandparents, particularly grandmothers, is often positively associated with child survival. Little research has explored the potential mechanisms driving these associations. We use data from rural Guatemala to test whether contact with and direct investment (advice and financial) from grandparents is associated with child health, proxied by height. Our results demonstrate the complexity of family relationships and their influence on child health, suggesting that both cooperative and competitive relationships exist within the family. The clearest evidence we find for grandparental influence is that having a living paternal grandmother tends to be negatively associated with child height. By contrast, contact with maternal kin appears broadly to be beneficial for child height, although these relationships are weaker. These patterns are mirrored in maternal body mass index, suggesting grandparental influence acts partly through maternal health. These findings support the hypotheses that, under conditions of limited resources, family relationships may be competitive within the family lineage which shares the same resource base, but cooperative when there are few costs to cooperation. Finally, financial assistance from maternal grandfathers is positively correlated with infant length but negatively with the height of older children, perhaps because the receipt of financial support is an indication of need. The provision of advice shows no associations with child height.

LIFTOFF - MERCURY-REDSTONE (MR)-2 - CAPE

NASA Image and Video Library

1961-01-31

S63-22731 (31 Jan. 1961) --- The launch of the Mercury-Redstone 2 (MR-2) suborbital mission from Cape Canaveral, Florida, on Jan. 31, 1961. Onboard the spacecraft was ?Ham?, a 37-pound chimpanzee. Despite an over-acceleration factor, the flight was considered to be successful. Following recovery Ham appeared to be in good physiological condition, but sometime later when he was shown the Mercury spacecraft it was visually apparent that he had no further interest in cooperating with the spaceflight program. Photo credit: NASA

Nuclear Challenges in Southeast Asia: Promoting Cooperation and Consensus

DTIC Science & Technology

2012-08-01

power rivalries has declined. This is most evident in the South China Sea. But it is also apparent in the debate over ASEAN’s ability to remain at the...Southeast Asia of the rise of China and India. Observers from outside the region worried that Southeast Asians have a rose-tinted view of the ability of...Vocal U.S. support for Southeast Asia in the South China Sea dispute may be creating expectations among some Southeast Asia countries that the

Empathy in cooperative versus non-cooperative situations: the contribution of self-report measures and autonomic responses.

PubMed

Balconi, Michela; Bortolotti, Adriana

2012-09-01

Shared representations, emotion comprehension, and emotion regulation constitute the basic macro components of social empathy. The present study integrated two different measures of empathic behavior in a social context: verbal self-report measures (empathic response, emotional involvement and emotional significance, and valence), and autonomic responses (facial expression-corrugator supercilii and zygomaticus major muscle-, SCR-skin conductance-, and HR-heart rate-). Participants (N = thirty-five) were presented with different interpersonal scene types (cooperation, non-cooperation, conflict, indifference). Different empathic sensitivity to these interpersonal situations was verified, since self-rating on empathy, emotional involvement and valence varied as a function of interpersonal context. Situation rated as more empathically significant were considered also as the most positive (cooperation) and negative (non cooperation and conflictual) and emotionally significant (high emotional significance of the scenes) in comparison with neutral scenes. Nevertheless, subjective empathic response and personal emotional involvement were found to be dissociated measures in non-cooperative condition. On the autonomic level, facial mimicry was linked to and coherent with the empathic response in cooperative, non-cooperative and conflictual conditions, whereas SCR and HR were increased only in response to cooperative and conflictual situation, rated as more involving by the subject. The convergence of these multidimensional measures was discussed: empirical evidences are far from able to warrant claims that processes of emotional contagion and simulation provide the sole, primary important way by which we come to know what others are feeling.

Non-cooperative Brownian donkeys: A solvable 1D model

NASA Astrophysics Data System (ADS)

Jiménez de Cisneros, B.; Reimann, P.; Parrondo, J. M. R.

2003-12-01

A paradigmatic 1D model for Brownian motion in a spatially symmetric, periodic system is tackled analytically. Upon application of an external static force F the system's response is an average current which is positive for F < 0 and negative for F > 0 (absolute negative mobility). Under suitable conditions, the system approaches 100% efficiency when working against the external force F.

Nano-Advantage in Enhanced Drug Delivery with Biodegradable Nanoparticles: Contribution of Reduced Clearance

PubMed Central

Kadam, Rajendra S.; Bourne, David W. A.

2012-01-01

The aim of this study was to investigate the contribution of reduced apparent clearance to the enhanced exposure reported for biodegradable nanoparticles after extravascular and intravascular routes of administration. Plasma concentration profiles for drug and nanoparticle formulations after administration by intravenous, intraduodenal, and oral routes were extracted from the literature. Data were fit to pharmacokinetic models using BOOMER. The compartmental pharmacokinetic analysis of literature data for six drugs (camptothecin, 9-nitrocamptothecin, epirubicin, vinpocetine, clozapine, and cyclosporine) showed that the encapsulation of drug molecules in nanoparticles significantly reduced the apparent clearance and prolonged the apparent circulation half-life compared with those for the plain drug. Positively charged nanoparticles assessed in this study had lower apparent clearance, lower elimination rate constant values, and longer apparent circulation half-life than neutral and negatively charged nanoparticles. After oral administration, a reduction in apparent clearance contributed substantially to elevations in plasma drug exposure with nanoparticles. For the drugs and delivery systems examined, the nano-advantage in drug delivery enhancement can be explained, in part, by reduced clearance. PMID:22498894

Identification of the potentiating mutations and synergistic epistasis that enabled the evolution of inter-species cooperation

DOE PAGES

Douglas, Sarah M.; Chubiz, Lon M.; Harcombe, William R.; ...

2017-05-11

Microbes often engage in cooperation through releasing biosynthetic compounds required by other species to grow. Given that production of costly biosynthetic metabolites is generally subjected to multiple layers of negative feedback, single mutations may frequently be insufficient to generate cooperative phenotypes. Synergistic epistatic interactions between multiple coordinated changes may thus often underlie the evolution of cooperation through overproduction of metabolites. To test the importance of synergistic mutations in cooperation we used an engineered bacterial consortium of an Escherichia coli methionine auxotroph and Salmonella enterica. S. enterica relies on carbon by-products from E. coli if lactose is the only carbon source.more » Directly selecting wild-type S. enterica in an environment that favored cooperation through secretion of methionine only once led to a methionine producer, and this producer both took a long time to emerge and was not very effective at cooperating. On the other hand, when an initial selection for resistance of S. enterica to a toxic methionine analog, ethionine, was used, subsequent selection for cooperation with E. coli was rapid, and the resulting double mutants were much more effective at cooperation. We found that potentiating mutations in metJ increase expression of metA, which encodes the first step of methionine biosynthesis. This increase in expression is required for the previously identified actualizing mutations in metA to generate cooperation. This work highlights that where biosynthesis of metabolites involves multiple layers of regulation, significant secretion of those metabolites may require multiple mutations, thereby constraining the evolution of cooperation.« less

Identification of the potentiating mutations and synergistic epistasis that enabled the evolution of inter-species cooperation

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

Douglas, Sarah M.; Chubiz, Lon M.; Harcombe, William R.

Microbes often engage in cooperation through releasing biosynthetic compounds required by other species to grow. Given that production of costly biosynthetic metabolites is generally subjected to multiple layers of negative feedback, single mutations may frequently be insufficient to generate cooperative phenotypes. Synergistic epistatic interactions between multiple coordinated changes may thus often underlie the evolution of cooperation through overproduction of metabolites. To test the importance of synergistic mutations in cooperation we used an engineered bacterial consortium of an Escherichia coli methionine auxotroph and Salmonella enterica. S. enterica relies on carbon by-products from E. coli if lactose is the only carbon source.more » Directly selecting wild-type S. enterica in an environment that favored cooperation through secretion of methionine only once led to a methionine producer, and this producer both took a long time to emerge and was not very effective at cooperating. On the other hand, when an initial selection for resistance of S. enterica to a toxic methionine analog, ethionine, was used, subsequent selection for cooperation with E. coli was rapid, and the resulting double mutants were much more effective at cooperation. We found that potentiating mutations in metJ increase expression of metA, which encodes the first step of methionine biosynthesis. This increase in expression is required for the previously identified actualizing mutations in metA to generate cooperation. This work highlights that where biosynthesis of metabolites involves multiple layers of regulation, significant secretion of those metabolites may require multiple mutations, thereby constraining the evolution of cooperation.« less

Geographic variation in apparent competition between native and invasive Phragmites australis.

PubMed

Bhattarai, Ganesh P; Meyerson, Laura A; Cronin, James T

2017-02-01

Apparent competition, the negative interaction between species mediated by shared natural enemies, is thought to play an important role in shaping the structure and dynamics of natural communities. However, its importance in driving species invasions, and whether the strength of this indirect interaction varies across the latitudinal range of the invasion, has not been fully explored. We performed replicated field experiments at four sites spanning 900 km along the Atlantic Coast of the United States to assess the presence and strength of apparent competition between sympatric native and invasive lineages of Phragmites australis. Four herbivore guilds were considered: stem-feeders, leaf-miners, leaf-chewers and aphids. We also tested the hypothesis that the strength of this interaction declines with increasing latitude. Within each site, native and invasive plants of P. australis were cross-transplanted between co-occurring native and invasive patches in the same marsh habitat and herbivore damage was evaluated at the end of the growing season. Apparent competition was evident for both lineages and involved all but the leaf-chewer guild. For native plants, total aphids per plant was 296% higher and the incidence of stem-feeding and leaf-mining herbivores was 34% and 221% higher, respectively, when transplanted into invasive than native patches. These data suggest that invasive P. australis has a negative effect on native P. australis via apparent competition. Averaged among herbivore types, the indirect effects of the invasive lineage on the native lineage was 57% higher than the reverse situation, suggesting that apparent competition was asymmetric. We also found that the strength of apparent competition acting against the native lineage was comparable to the benefits to the invasive lineage from enemy release (i.e., proportionately lower mean herbivory of the invasive relative to the native taxa). Finally, we found the first evidence that the strength of apparent competition acting against the native lineage (from stem-feeders only) decreased with increasing latitude. These results suggest that not only could apparent competition be of tantamount importance to enemy release in enhancing the establishment and spread of invasive taxa, but also that these indirect and direct herbivore effects could vary over the invasion range. © 2016 by the Ecological Society of America.

The Russian-U.S. Experience with Development Joint Medical Support Procedures for Before and After Long-Duration Space Flights

NASA Technical Reports Server (NTRS)

Morgun, V. V.; Voronin, L. I.; Kaspransky, R. R.; Pool, S. L.; Barratt, M. R.; Novinkov, O. L.

1999-01-01

As the Russian Space Agency (RSA) and the U.S. National Aviation and Space Administration (NASA) began in the mid 1990s to plan a preliminary cooperative flight program in anticipation of the International Space Station, programmatic and philosophical differences became apparent in the technical and medical approaches of the two agencies. This paper briefly describes some of these differences and the process by which the two sides resolved differences in their approaches to the medical selection and certification of Shuttle-Mir crew members. These negotiations formed the basis for developing policies on other aspects of the medical support function for international missions, including crew training, preflight and postflight data collection, and rehabilitation protocols. The experience gained through this cooperative effort has been invaluable for developing medical care capabilities for the International Space Station.

A Mechanistic Model for Cooperative Behavior of Co-transcribing RNA Polymerases

PubMed Central

Heberling, Tamra; Davis, Lisa; Gedeon, Jakub; Morgan, Charles; Gedeon, Tomáš

2016-01-01

In fast-transcribing prokaryotic genes, such as an rrn gene in Escherichia coli, many RNA polymerases (RNAPs) transcribe the DNA simultaneously. Active elongation of RNAPs is often interrupted by pauses, which has been observed to cause RNAP traffic jams; yet some studies indicate that elongation seems to be faster in the presence of multiple RNAPs than elongation by a single RNAP. We propose that an interaction between RNAPs via the torque produced by RNAP motion on helically twisted DNA can explain this apparent paradox. We have incorporated the torque mechanism into a stochastic model and simulated transcription both with and without torque. Simulation results illustrate that the torque causes shorter pause durations and fewer collisions between polymerases. Our results suggest that the torsional interaction of RNAPs is an important mechanism in maintaining fast transcription times, and that transcription should be viewed as a cooperative group effort by multiple polymerases. PMID:27517607

Impact of concentration and species of sulfamethoxazole and ofloxacin on their adsorption kinetics on sediments.

PubMed

Wang, Peng; Zhang, Di; Zhang, Huang; Li, Hao; Ghosh, Saikat; Pan, Bo

2017-05-01

Antibiotics are used widely in human and veterinary medicine and are ubiquitous in environmental matrices worldwide. The influence of the concentration of antibiotics on adsorption kinetics is still unclear. This study used sulfamethoxazole (SMX) and ofloxacin (OFL) as adsorbates to investigate the adsorption kinetics on sediment affected by varying concentrations of antibiotics adsorbable species. At the experimental pH values, the major adsorbed species of SMX and OFL on sediment were SMX 0 and OFL + by hydrophobic interaction and electrostatic attraction, respectively. The apparent adsorption rate of SMX was not affected by the initial concentration and the pH values because the hydrophobic interactions were concentration-independent and charge-independent. However, the apparent adsorption rate of OFL significantly slowed down as the initial concentration increased. The adsorbed OFL + effectively neutralized the negative charges of the sediment, leading to a reduced adsorption rate of subsequent OFL + . The neutralization effect was greatly enhanced due to the increased OFL + with the increasing OFL concentration. Additionally, the apparent adsorption rate of OFL significantly increased at higher pH due to the reduced neutralization effect that resulted from the decreased OFL + and increased negative charges of the sediment surface. This study implied that the adsorption kinetics of antibiotics was greatly dominated by the concentration of adsorbable species rather than apparent overall concentration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Early Detection of Online Auction Opportunistic Sellers through the Use of Negative-Positive Feedback

ERIC Educational Resources Information Center

Reinert, Gregory J.

2010-01-01

Apparently fraud is a growth industry. The monetary losses from Internet fraud have increased every year since first officially reported by the Internet Crime Complaint Center (IC3) in 2000. Prior research studies and third-party reports of fraud show rates substantially higher than eBay's reported negative feedback rate of less than 1%. The…

Dynamics of a small re-introduced population of wild dogs over 25 years: Allee effects and the implications of sociality for endangered species' recovery.

PubMed

Somers, Michael J; Graf, Jan A; Szykman, Micaela; Slotow, Rob; Gusset, Markus

2008-11-01

We analysed 25 years (1980-2004) of demographic data on a small re-introduced population of endangered African wild dogs (Lycaon pictus) in Hluhluwe-iMfolozi Park (HiP), South Africa, to describe population and pack dynamics. As small populations of cooperative breeders may be particularly prone to Allee effects, this extensive data set was used to test the prediction that, if Allee effects occur, aspects of reproductive success, individual survival and population growth should increase with pack and population size. The results suggest that behavioural aspects of wild dogs rather than ecological factors (i.e. competitors, prey and rainfall) primarily have been limiting the HiP wild dog population, particularly a low probability of finding suitable mates upon dispersal at low pack number (i.e. a mate-finding Allee effect). Wild dogs in HiP were not subject to component Allee effects at the pack level, most likely due to low interspecific competition and high prey availability. This suggests that aspects of the environment can mediate the strength of Allee effects. There was also no demographic Allee effect in the HiP wild dog population, as the population growth rate was significantly negatively related to population size, despite no apparent ecological resource limitation. Such negative density dependence at low numbers indicates that behavioural studies of the causal mechanisms potentially generating Allee effects in small populations can provide a key to understanding their dynamics. This study demonstrates how aspects of a species' social behaviour can influence the vulnerability of small populations to extinction and illustrates the profound implications of sociality for endangered species' recovery.

Survey of aflatoxin concentrations in wild bird seed purchased in Texas.

PubMed

Henke, S E; Gallardo, V C; Martinez, B; Balley, R

2001-10-01

The use of backyard feeders to attract avian wildlife is a common practice throughout the United States. However, feeding wildlife may create a problem due to aflatoxin, a harmful fungal metabolite, which can affect wildlife that are fed contaminated grain. Our study was initiated to determine if songbirds were being exposed to aflatoxin-contaminated feed throughout Texas. Bags of wild bird seed (n = 142) were purchased from grain cooperatives, grocery stores, and pet shops located in the panhandle, central, south, east, and west regions of Texas during spring and summer 1999. Aflatoxin concentrations in bird seed ranged from non-detectable to 2,780 micrograms/kg. Overall, 17% of samples had aflatoxin concentrations greater than 100 micrograms/kg, of which 83% contained corn as an ingredient. Retail establishment effects were noted in the southern and western regions of Texas, with average concentrations of aflatoxin greater from bags of bird seed purchased from grain cooperatives, followed by pet shops, then grocery stores. Regional differences in aflatoxin levels were not apparent from bags of seed purchased at pet shops: however, regional differences were noted in aflatoxin levels from seeds obtained at grocery stores and grain cooperatives. Average aflatoxin concentration from seed purchased at grocery stores was greatest in the panhandle region, followed by the remaining regions. Within grain cooperatives, the panhandle, south, and west regions of Texas exhibited higher levels of aflatoxin-contaminated bird seed than cooperatives within the east and central regions of Texas. Granivorous songbirds in Texas are exposed to aflatoxins at backyard feeders, which may be a significant morbidity and mortality factor.

Aeronautical Decision Making - Cockpit Resource Management

DTIC Science & Technology

1989-01-01

perspective, the development of CRM concepts as seen in the kickoff workshop held at the NASA Ames Research Center (Cooper, White, and Lauber, 1979...something to put in the place of worrying a pleasant thought. A though stoppage (Stop negative thought patterns by shouting words like ’stop’ or ’no’ in the...the Situation." In: G.E. Cooper, M.D. White, and J.K. Lauber (Eds) Resource management in the cockpit. Moffett Field, CA: NASA Ames Research Center

[Demonstrating that monitoring and punishing increase non-cooperative behavior in a social dilemma game].

PubMed

Kitakaji, Yoko; Ohnuma, Susumu

2014-04-01

This research demonstrated the negative influence of monitoring and punishing during a social dilemma game, taking the illegal dumping of industrial waste as an example. The first study manipulated three conditions: a producing-industries monitoring condition (PIM), an administrative monitoring condition (ADM), and a control condition (no monitoring). The results showed that non-cooperative behavior was more frequent in the PIM condition than in the control condition. The second study had three conditions: a punishing condition (PC), a monitoring condition (MC), and a control condition (no monitoring, no punishing). The results indicated that non-cooperative behavior was observed the most in the PC, and the least in the control condition. Furthermore, information regarding other players' costs and benefits was shared the most in the control conditions in both studies. The results suggest that sanctions prevent people from sharing information, which decreases expectations of mutual cooperation.

Spatially correlated heterogeneous aspirations to enhance network reciprocity

NASA Astrophysics Data System (ADS)

Tanimoto, Jun; Nakata, Makoto; Hagishima, Aya; Ikegaya, Naoki

2012-02-01

Perc & Wang demonstrated that aspiring to be the fittest under conditions of pairwise strategy updating enhances network reciprocity in structured populations playing 2×2 Prisoner's Dilemma games (Z. Wang, M. Perc, Aspiring to the fittest and promoted of cooperation in the Prisoner's Dilemma game, Physical Review E 82 (2010) 021115; M. Perc, Z. Wang, Heterogeneous aspiration promotes cooperation in the Prisoner's Dilemma game, PLOS one 5 (12) (2010) e15117). Through numerical simulations, this paper shows that network reciprocity is even greater if heterogeneous aspirations are imposed. We also suggest why heterogeneous aspiration fosters network reciprocity. It distributes strategy updating speed among agents in a manner that fortifies the initially allocated cooperators' clusters against invasion. This finding prompted us to further enhance the usual heterogeneous aspiration cases for heterogeneous network topologies. We find that a negative correlation between degree and aspiration level does extend cooperation among heterogeneously structured agents.

Facial Likability and Smiling Enhance Cooperation, but Have No Direct Effect on Moralistic Punishment.

PubMed

Mieth, Laura; Bell, Raoul; Buchner, Axel

2016-09-01

The present study serves to test how positive and negative appearance-based expectations affect cooperation and punishment. Participants played a prisoner's dilemma game with partners who either cooperated or defected. Then they were given a costly punishment option: They could spend money to decrease the payoffs of their partners. Aggregated over trials, participants spent more money for punishing the defection of likable-looking and smiling partners compared to punishing the defection of unlikable-looking and nonsmiling partners, but only because participants were more likely to cooperate with likable-looking and smiling partners, which provided the participants with more opportunities for moralistic punishment. When expressed as a conditional probability, moralistic punishment did not differ as a function of the partners' facial likability. Smiling had no effect on the probability of moralistic punishment, but punishment was milder for smiling in comparison to nonsmiling partners.

Relationship of symptomatology, gender, and antipsychotic drug treatment with plasma homovanillic acid in schizophrenia.

PubMed

Zhang, Z J; Reynolds, G P; Ramchand, C; Peet, M; Shah, S

2001-01-01

To study the role of dopamine neurotransmission in schizophrenia and its drug treatment by assessing the relationship of plasma homovanillic acid (pHVA), a major central dopamine metabolite to various clinical parameters in schizophrenic patients. pHVA was measured by high-performance liquid chromatography with electrochemical detection in a large cohort of both medicated and unmedicated DSM-IV schizophrenic patients. Prior to the measurement of pHVA, the patients were rated on the schedule for the assessment of positive and negative symptoms (PANSS). (1) pHVA in 46 patients receiving antipsychotic drugs was decreased, and in 58 drug-free patients increased, (7.4+/-2.7) microg/L and (10+/-4) microg/L compared with a matched control group (9 microg/L+/-3 microg/L, n=62) (ANOVA F=8.57, df=2, P < 0.01), respectively. Within the drug-free group, pHVA was higher in the patients with a more negative symptom profile. (2) No significant correlation of pHVA with overall SAPS or SANS scores was apparent in the drug-free patients, although within the SANS subscales, a significant relationships to anhedonia-asociality (r=0.32, P < 0.05) was apparent. The male drug-free patients showed a positive correlation of pHVA with negative symptoms (r=0.42, P < 0.05) while females showed no significant relationship with any PANSS subscales. The results suggest that an increased dopaminergic metabolism is apparent in (male) schizophrenic patients with predominantly negative symptoms, supporting reports that this change in neuronal activity may be related to the neuropathological abnormalities seen in the disease, which may differ between males and females. Such neuronal deficits of developmental origin may thus result in an elevation/disinhibition of central dopamine metabolism in schizophrenia.

Age, sex and social influences on adult survival in the cooperatively breeding Karoo Scrub-robin

USGS Publications Warehouse

Lloyd, Penn; Martin, Thomas E.; Taylor, Andrew; Braae, Anne; Altwegg, Res

2016-01-01

Among cooperatively breeding species, helpers are hypothesised to increase the survival of breeders by reducing breeder workload in offspring care and increased group vigilance against predators. Furthermore, parental nepotism or other benefits of group living may provide a survival benefit to young that delay dispersal to help. We tested these hypotheses in the Karoo Scrub-robin (Cercotrichas coryphaeus), a long-lived, and facultative cooperatively breeding species in which male helpers make substantial contributions to the care of young. We found that annual breeder survival in the presence of helpers did not differ detectably from breeders without helpers or breeders that lost helpers. Furthermore, helpers did not gain a survival benefit from deferred breeding; apparent survival did not differ detectably between male helpers and male breeders followed from one year old. These results are consistent with other studies suggesting a lack of adult survival benefits among species where breeders do not substantially reduce workloads when helpers are present. They are also consistent with the hypothesis that males that delay dispersal make the ‘best of a bad job’ by helping on their natal territory to gain indirect fitness benefits when they are unable to obtain a territory vacancy nearby.

Cooperativity and complexity in the binding of anions and cations to a tetratopic ion-pair host.

PubMed

Howe, Ethan N W; Bhadbhade, Mohan; Thordarson, Pall

2014-05-21

Cooperative interactions play a very important role in both natural and synthetic supramolecular systems. We report here on the cooperative binding properties of a tetratopic ion-pair host 1. This host combines two isophthalamide anion recognition sites with two unusual "half-crown/two carbonyl" cation recognition sites as revealed by the combination of single-crystal X-ray analysis of the free host and the 1:2 host:calcium cation complex, together with two-dimensional NMR and computational studies. By systematically comparing all of the binding data to several possible binding models and focusing on four different variants of the 1:2 binding model, it was in most cases possible to quantify these complex cooperative interactions. The data showed strong negative cooperativity (α = 0.01-0.05) of 1 toward chloride and acetate anions, while for cations the results were more variable. Interestingly, in the competitive (CDCl3/CD3OD (9:1, v/v)) solvent, the addition of calcium cations to the tetratopic ion-pair host 1 allosterically switched "on" chloride binding that is otherwise not present in this solvent system. The insight into the complexity of cooperative interactions revealed in this study of the tetratopic ion-pair host 1 can be used to design better cooperative supramolecular systems for information transfer and catalysis.

Social distance influences the outcome evaluation of cooperation and conflict: Evidence from event-related potentials.

PubMed

Chen, Yezi; Lu, Jiamei; Wang, Yiwen; Feng, Zhouqi; Yuan, Bo

2017-04-24

Previous research shows that social distance plays an important role in promoting cooperation and that subtle cues that reduce social distance increase the tendency to cooperate. However, it is unclear how social distance influences our outcome evaluation of cooperative and conflict feedback. The present study investigated the influence of social distance on cooperative and conflict behavior and the evaluation process of the cooperative and conflict outcomes, using the event-related potentials (ERPs) technique. We recorded ERPs from 14 normal adults playing a social game task against a friend and a stranger. The results showed that the FRN (Feedback Related Negativity) and P300 were affected by the opponent's choice to cooperate or aggress; however, only the P300 was affected by social distance. Specifically, when the opponent chose to cooperate, the feedback elicited a smaller FRN and a larger P300 amplitude; and compared with playing against friends, the P300 had a larger amplitude when participants gaming with strangers. Our results indicate that at the early stage of the evaluation of cooperation and conflict outcomes, individuals may initially and quickly encode the valence of outcomes, judging whether an outcome is consistent with their expectations. However, at the late stage, which involves a top-down cognitive appraisal process, some social factors, such as social distance, may moderate processing of attention resource allocation of feedback about outcomes, and of higher-level motivation/affective appraisal. Copyright © 2017 Elsevier B.V. All rights reserved.

The take-it-or-leave-it option allows small penalties to overcome social dilemmas

PubMed Central

Sasaki, Tatsuya; Brännström, Åke; Dieckmann, Ulf; Sigmund, Karl

2012-01-01

Self-interest frequently causes individuals engaged in joint enterprises to choose actions that are counterproductive. Free-riders can invade a society of cooperators, causing a tragedy of the commons. Such social dilemmas can be overcome by positive or negative incentives. Even though an incentive-providing institution may protect a cooperative society from invasion by free-riders, it cannot always convert a society of free-riders to cooperation. In the latter case, both norms, cooperation and defection, are stable: To avoid a collapse to full defection, cooperators must be sufficiently numerous initially. A society of free-riders is then caught in a social trap, and the institution is unable to provide an escape, except at a high, possibly prohibitive cost. Here, we analyze the interplay of (a) incentives provided by institutions and (b) the effects of voluntary participation. We show that this combination fundamentally improves the efficiency of incentives. In particular, optional participation allows institutions punishing free-riders to overcome the social dilemma at a much lower cost, and to promote a globally stable regime of cooperation. This removes the social trap and implies that whenever a society of cooperators cannot be invaded by free-riders, it will necessarily become established in the long run, through social learning, irrespective of the initial number of cooperators. We also demonstrate that punishing provides a “lighter touch” than rewarding, guaranteeing full cooperation at considerably lower cost. PMID:22232694

Quantification of transcription factor-DNA binding affinity in a living cell

PubMed Central

Belikov, Sergey; Berg, Otto G.; Wrange, Örjan

2016-01-01

The apparent dissociation constant (Kd) for specific binding of glucocorticoid receptor (GR) and androgen receptor (AR) to DNA was determined in vivo in Xenopus oocytes. The total nuclear receptor concentration was quantified as specifically retained [3H]-hormone in manually isolated oocyte nuclei. DNA was introduced by nuclear microinjection of single stranded phagemid DNA, chromatin is then formed during second strand synthesis. The fraction of DNA sites occupied by the expressed receptor was determined by dimethylsulphate in vivo footprinting and used for calculation of the receptor-DNA binding affinity. The forkhead transcription factor FoxA1 enhanced the DNA binding by GR with an apparent Kd of ∼1 μM and dramatically stimulated DNA binding by AR with an apparent Kd of ∼0.13 μM at a composite androgen responsive DNA element containing one FoxA1 binding site and one palindromic hormone receptor binding site known to bind one receptor homodimer. FoxA1 exerted a weak constitutive- and strongly cooperative DNA binding together with AR but had a less prominent effect with GR, the difference reflecting the licensing function of FoxA1 at this androgen responsive DNA element. PMID:26657626

Orangutans (Pongo pygmaeus) do not form expectations based on their partner's outcomes.

PubMed

Brosnan, Sarah F; Flemming, Timothy; Talbot, Catherine F; Mayo, Laura; Stoinski, Tara

2011-01-01

Several primate species form expectations based on others' outcomes, responding negatively when their outcomes differ from their partners'. The function and evolutionary pathway of this behavior are unknown, in part because all of the species which have been tested thus far share traits related to a gregarious lifestyle, intelligence, and cooperativeness. Our goal was to test whether inequity is a homology among primates or a convergence by comparing one species known to show social comparisons, the chimpanzee, to another great ape which differs on several of these life history characteristics. Using a protocol identical to one used previously with chimpanzees, we tested whether orangutans, an intelligent but predominantly solitary species with few opportunities to cooperate, responded similarly. To allow for a strong comparison with chimpanzees (and other species), we used socially housed adults of both sexes, tested with members of their social group. Orangutans did not respond negatively to inequity, supporting previous findings and indicating that inequity responses in apes are likely a convergence based on either sociality or cooperative tendency. These results in such closely related species highlight the need for additional comparative studies to understand better the function and evolution of social behaviors. Copyright © 2011 S. Karger AG, Basel.

Correlation of Positive and Negative Reciprocity Fails to Confer an Evolutionary Advantage: Phase Transitions to Elementary Strategies

NASA Astrophysics Data System (ADS)

Szolnoki, Attila; Perc, Matjaž

2013-10-01

Economic experiments reveal that humans value cooperation and fairness. Punishing unfair behavior is therefore common, and according to the theory of strong reciprocity, it is also directly related to rewarding cooperative behavior. However, empirical data fail to confirm that positive and negative reciprocity are correlated. Inspired by this disagreement, we determine whether the combined application of reward and punishment is evolutionarily advantageous. We study a spatial public goods game, where in addition to the three elementary strategies of defection, rewarding, and punishment, a fourth strategy that combines the latter two competes for space. We find rich dynamical behavior that gives rise to intricate phase diagrams where continuous and discontinuous phase transitions occur in succession. Indirect territorial competition, spontaneous emergence of cyclic dominance, as well as divergent fluctuations of oscillations that terminate in an absorbing phase are observed. Yet, despite the high complexity of solutions, the combined strategy can survive only in very narrow and unrealistic parameter regions. Elementary strategies, either in pure or mixed phases, are much more common and likely to prevail. Our results highlight the importance of patterns and structure in human cooperation, which should be considered in future experiments.

The Hard Problem of Cooperation

PubMed Central

Eriksson, Kimmo; Strimling, Pontus

2012-01-01

Based on individual variation in cooperative inclinations, we define the “hard problem of cooperation” as that of achieving high levels of cooperation in a group of non-cooperative types. Can the hard problem be solved by institutions with monitoring and sanctions? In a laboratory experiment we find that the answer is affirmative if the institution is imposed on the group but negative if development of the institution is left to the group to vote on. In the experiment, participants were divided into groups of either cooperative types or non-cooperative types depending on their behavior in a public goods game. In these homogeneous groups they repeatedly played a public goods game regulated by an institution that incorporated several of the key properties identified by Ostrom: operational rules, monitoring, rewards, punishments, and (in one condition) change of rules. When change of rules was not possible and punishments were set to be high, groups of both types generally abided by operational rules demanding high contributions to the common good, and thereby achieved high levels of payoffs. Under less severe rules, both types of groups did worse but non-cooperative types did worst. Thus, non-cooperative groups profited the most from being governed by an institution demanding high contributions and employing high punishments. Nevertheless, in a condition where change of rules through voting was made possible, development of the institution in this direction was more often voted down in groups of non-cooperative types. We discuss the relevance of the hard problem and fit our results into a bigger picture of institutional and individual determinants of cooperative behavior. PMID:22792282

Decelerated invasion and waning-moon patterns in public goods games with delayed distribution.

PubMed

Szolnoki, Attila; Perc, Matjaž

2013-05-01

We study the evolution of cooperation in the spatial public goods game, focusing on the effects that are brought about by the delayed distribution of goods that accumulate in groups due to the continuous investments of cooperators. We find that intermediate delays enhance network reciprocity because of a decelerated invasion of defectors, who are unable to reap the same high short-term benefits as they do in the absence of delayed distribution. Long delays, however, introduce a risk because the large accumulated wealth might fall into the wrong hands. Indeed, as soon as the curvature of a cooperative cluster turns negative, the engulfed defectors can collect the heritage of many generations of cooperators and by doing so start a waning-moon pattern that nullifies the benefits of decelerated invasion. Accidental meeting points of growing cooperative clusters may also act as triggers for the waning-moon effect, thus linking the success of cooperators with their propensity to fail in a rather bizarre way. Our results highlight that "investing in the future" is a good idea only if that future is sufficiently near and not likely to be burdened by inflation.

Marital relationship, parenting practices, and social skills development in preschool children.

PubMed

Hosokawa, Rikuya; Katsura, Toshiki

2017-01-01

This study examined the pathways by which destructive and constructive marital conflict leading to social skills development in preschool children, are mediated through negative and positive parenting practices. Mothers of 2931 Japanese children, aged 5-6 years, completed self-report questionnaires regarding their marital relationship (the Quality of co-parental communication scale) and parental practices (the Alabama parenting questionnaire). The children's teachers evaluated their social skills using the Social skills scale. Path analyses revealed significant direct paths from destructive marital conflict to negative parenting practices and lower scores on the self-control component of social skills. In addition, negative parenting practices mediated the relationship between destructive marital conflict and lower scores on cooperation, self-control, and assertion. Our analyses also revealed significant direct paths from constructive marital conflict to positive parenting practices, and higher scores on cooperation and assertion. Positive parenting practices mediated the relationship between constructive marital conflict and higher scores on self-control and assertion. These findings suggest that destructive and constructive marital conflict may directly and indirectly influence children's social skills development through the mediation of parenting practices.

[Impact of Socioeconomic Risk Exposure on Maternal Sensitivity, Stress and Family Functionality].

PubMed

Sidor, Anna; Köhler, Hubert; Cierpka, Manfred

2018-03-01

Impact of Socioeconomic Risk Exposure on Maternal Sensitivity, Stress and Family Functionality Parental stress exposure can influence the parent-child relationship, child development and child wellbeing in negative ways. The aim of this study was to investigate the impact of socio-economic risk exposure on the quality of the mother-child-interaction and family functionality. A sample of 294 mother-infant dyads at psychosocial risk was compared with a lower-risk, middle-class sample of 125 mother-infant-dyads in regard to maternal sensitivity/child's cooperation (CARE-Index), maternal stress (PSI-SF) and family functionality (FB-K). Lower levels of maternal sensitivity/child's cooperation and by trend also of the family functionality were found among the mothers from the at-risk sample in comparison to the low-risk sample. The level of maternal stress was similar in both samples. The results underpin the negative effects of a socio-economic risk exposure on the mother-child relationship. An early, sensitivity-focused family support could be encouraged to counteract the negative effects of early socioeconomic stress.

An fMRI study of joint action–varying levels of cooperation correlates with activity in control networks

PubMed Central

Chaminade, Thierry; Marchant, Jennifer L.; Kilner, James; Frith, Christopher D.

2012-01-01

As social agents, humans continually interact with the people around them. Here, motor cooperation was investigated using a paradigm in which pairs of participants, one being scanned with fMRI, jointly controlled a visually presented object with joystick movements. The object oscillated dynamically along two dimensions, color and width of gratings, corresponding to the two cardinal directions of joystick movements. While the overall control of each participant on the object was kept constant, the amount of cooperation along the two dimensions varied along four levels, from no (each participant controlled one dimension exclusively) to full (each participant controlled half of each dimension) cooperation. Increasing cooperation correlated with BOLD signal in the left parietal operculum and anterior cingulate cortex (ACC), while decreasing cooperation correlated with activity in the right inferior frontal and superior temporal gyri, the intraparietal sulci and inferior temporal gyri bilaterally, and the dorsomedial prefrontal cortex. As joint performance improved with the level of cooperation, we assessed the brain responses correlating with behavior, and found that activity in most of the areas associated with levels of cooperation also correlated with the joint performance. The only brain area found exclusively in the negative correlation with cooperation was in the dorso medial frontal cortex, involved in monitoring action outcome. Given the cluster location and condition-related signal change, we propose that this region monitored actions to extract the level of cooperation in order to optimize the joint response. Our results, therefore, indicate that, in the current experimental paradigm involving joint control of a visually presented object with joystick movements, the level of cooperation affected brain networks involved in action control, but not mentalizing. PMID:22715326

Physiologic underpinnings of negative BOLD cerebrovascular reactivity in brain ventricles.

PubMed

Thomas, Binu P; Liu, Peiying; Aslan, Sina; King, Kevin S; van Osch, Matthias J P; Lu, Hanzhang

2013-12-01

With a growing need for specific biomarkers in vascular diseases, there has been a surging interest in mapping cerebrovascular reactivity (CVR) of the brain. This index can be measured by conducting a hypercapnia challenge while acquiring blood-oxygenation-level-dependent (BOLD) signals. A BOLD signal increase with hypercapnia is the expected outcome and represents the majority of literature reports; in this work we report an intriguing observation of an apparently negative BOLD CVR response at 3T, during inhalation of 5% CO2 with balance medical air. These "negative-CVR" clusters were specifically located in the ventricular regions of the brain, where CSF is abundant and results in an intense baseline signal. The amplitude of the CVR response was -0.51±0.44% (N=14, age 26±4 years). We hypothesized that this observation might not be due to a decrease in oxygenation but rather a volume effect in which bright CSF signal is replaced by a less intensive blood signal as a result of vasodilation. To test this, we performed an inversion-recovery (IR) experiment to suppress the CSF signal (N=10, age 27±5 years). This maneuver in imaging sequence reversed the sign of the signal response (to 0.66±0.25%), suggesting that the volume change was the predominant reason for the apparently negative CVR in the BOLD experiment. Further support of this hypothesis was provided by a BOLD hyperoxia experiment, in which no voxels showed a negative response, presumably because vasodilation is not usually associated with this challenge. Absolute CBF response to hypercapnia was measured in a new group of subjects (N=8, age 29±7 years) and it was found that CBF in ventricular regions increased by 48% upon CO2 inhalation, suggesting that blood oxygenation most likely increased rather than decreased. The findings from this study suggest that CO2 inhalation results in the dilation of ventricular vessels accompanied by shrinkage in CSF space, which is responsible for the apparently negative CVR in brain ventricles. © 2013.

Plasma homovanillic acid in untreated schizophrenia--relationship with symptomatology and sex.

PubMed

Zhang, Z J; Peet, M; Ramchand, C N; Shah, S; Reynolds, G P

2001-01-01

Plasma homovanillic acid (pHVA) concentrations are considered to reflect, in part, central dopamine metabolism and thus may be of value in assessing the role of dopamine neurotransmission in schizophrenia. Furthermore, some recent studies have suggested a relationship of pHVA with symptomatology. We have undertaken a study of pHVA in a large cohort of unmedicated DSM-IV schizophrenic patients in order to assess the relationship of pHVA to various clinical parameters. pHVA in 58 drug-free patients (10.11+/-0.52 ng/ml) was significantly elevated in comparison with 62 matched control subjects (8.77+/-0.39 ng/ml). pHVA was found to be higher in patients with a more negative syndrome. No significant correlation of pHVA with overall SAPS or SANS scores was apparent in the patients although, within the SANS subscales, a significant relationship to anhedonia-asociality was apparent. Interestingly, the male drug-free patients showed a correlation of pHVA with negative symptoms defined by SANS and several SANS subscales, while females showed no significant relationship with any SANS subscales. The results may suggest that an increased dopaminergic turnover is apparent in (male) schizophrenic patients with predominantly negative symptoms, providing some support for reports that this change in neuronal activity may be related to the neuropathological abnormalities seen in the disease, which may themselves differ between males and females. Such neuronal deficits of developmental or degenerative origin may thus result in an elevation/disinhibition of central dopamine metabolism in schizophrenia.

Memory for reputational trait information: is social-emotional information processing less flexible in old age?

PubMed

Bell, Raoul; Giang, Trang; Mund, Iris; Buchner, Axel

2013-12-01

How do younger and older adults remember reputational trait information about other people? In the present study, trustworthy-looking and untrustworthy-looking faces were paired with cooperation or cheating in a cooperation game. In a surprise source-memory test, participants were asked to rate the likability of the faces, and were required to remember whether the faces were associated with negative or positive outcomes. The social expectations of younger and older adults were clearly affected by a priori facial trustworthiness. Facial trustworthiness was associated with high cooperation-game investments, high likability ratings, and a tendency toward guessing that a face belonged to a cooperator instead of a cheater in both age groups. Consistent with previous results showing that emotional memory is spared from age-related decline, memory for the association between faces and emotional reputational information was well preserved in older adults. However, younger adults used a flexible encoding strategy to remember the social interaction partners. Source-memory was best for information that violated their (positive) expectations. Older adults, in contrast, showed a uniform memory bias for negative social information; their memory performance was not modulated by their expectations. This finding suggests that older adults are less likely to adjust their encoding strategies to their social expectations than younger adults. This may be in line with older adults' motivational goals to avoid risks in social interactions. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Authorities' Coercive and Legitimate Power: The Impact on Cognitions Underlying Cooperation

PubMed Central

Hofmann, Eva; Hartl, Barbara; Gangl, Katharina; Hartner-Tiefenthaler, Martina; Kirchler, Erich

2017-01-01

The execution of coercive and legitimate power by an authority assures cooperation and prohibits free-riding. While coercive power can be comprised of severe punishment and strict monitoring, legitimate power covers expert, and informative procedures. The perception of these powers wielded by authorities stimulates specific cognitions: trust, relational climates, and motives. With four experiments, the single and combined impact of coercive and legitimate power on these processes and on intended cooperation of n1 = 120, n2 = 130, n3 = 368, and n4 = 102 student participants is investigated within two exemplary contexts (tax contributions, insurance claims). Findings reveal that coercive power increases an antagonistic climate and enforced compliance, whereas legitimate power increases reason-based trust, a service climate, and voluntary cooperation. Unexpectedly, legitimate power is additionally having a negative effect on an antagonistic climate and a positive effect on enforced compliance; these findings lead to a modification of theoretical assumptions. However, solely reason-based trust, but not climate perceptions and motives, mediates the relationship between power and intended cooperation. Implications for theory and practice are discussed. PMID:28149286

Russia’s Nuclear Weapons Dilemma: A Cooperative Approach to International Security in the 1990s

DTIC Science & Technology

1993-01-01

examined in order to understand the apparent and real problems facing the Russian 2 Sam Nunn et al., "Trip Report: A Visit to the Commonwealth of...could argue that this is not an unreasonable amount 10 Bohdan Nahaylo, "The Birth of an Independent Ukraine," Report on the USSR 3, no. 50 (1991): 3-4...34 Washington Post, 29 March 1992, C3. 13 Robert L. Galluci, "Disposing of Nuclear Weapons in the Former Soviet Union," U.S. Department of State

Diagnosing Abiotic Degradation

EPA Science Inventory

The abiotic degradation of chlorinated solvents in ground water can be difficult to diagnose. Under current practice, most of the “evidence” is negative; specifically the apparent disappearance of chlorinated solvents with an accumulation of vinyl chloride, ethane, ethylene, or ...

Effect of molecular structure on the hydration of structurally related antidepressant drugs

NASA Astrophysics Data System (ADS)

Cheema, M. A.; Taboada, P.; Barbosa, S.; Siddiq, M.; Mosquera, V.

Apparent molal volumes and adiabatic compressibilities of aqueous solutions of the amphiphilic cationic antidepressant drugs butriptyline and doxepin hydrochlorides have been determined from density and ultrasound velocity measurements in the temperature range 20-50°C. Critical concentrations for aggregation of these drugs were obtained from ultrasound velocity measurements. Negative deviations from the Debye-Hückel limiting law of the apparent molal volume were obtained from both drugs in all temperature ranges, except for doxepin at 50°C, which provides evidence of no pre-association at concentrations below the critical concentration. Apparent molal adiabatic compressibilities of the aggregates formed by these drugs were typical of those corresponding for an aggregate formed by a stacking process.

Discussion on joint operation of wind farm and pumped-storage hydroplant

NASA Astrophysics Data System (ADS)

Li, Caifang; Wu, Yichun; Liang, Hao; Li, Miao

2017-12-01

Due to the random fluctuations in wind power, large amounts of grid integration will have a negative impact on grid operation and the consumers. The joint operation with pumped-storage hydroplant with good peak shaving performance can effectively reduce the negative impact on the safety and economic operation of power grid, and improve the utilization of wind power. In addition, joint operation can achieve the optimization of green power and improve the comprehensive economic benefits. Actually, the rational profit distribution of joint operation is the premise of sustainable and stable cooperation. This paper focuses on the profit distribution of joint operation, and applies improved shapely value method, which taking the investments and the contributions of each participant in the cooperation into account, to determine the profit distribution. Moreover, the distribution scheme can provide an effective reference for the actual joint operation of wind farm and pumped-storage hydroplant.

Fermion Cooper pairing with unequal masses: Standard field theory approach

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

He Lianyi; Jin Meng; Zhuang Pengfei

Fermion Cooper pairing with unequal masses is investigated in a standard field theory approach. We derived the superfluid density and Meissner mass squared of the U(1) gauge field in a general two-species model and found that the often used proportional relation between the two quantities is broken when the fermion masses are unequal. In the weak-coupling region, the superfluid density is always negative but the Meissner mass squared becomes mostly positive when the mass ratio between the pairing fermions is large enough. We established a proper momentum configuration of the LOFF pairing with unequal masses and showed that the LOFFmore » state is energetically favored due to the negative superfluid density. The single-plane-wave LOFF state is physically equivalent to an anisotropic state with a spontaneously generated superflow. The extension to a finite-range interaction is briefly discussed.« less

Cooperativity and pseudo-cooperativity in the glutathione S-transferase from Plasmodium falciparum.

PubMed

Liebau, Eva; De Maria, Francesca; Burmeister, Cora; Perbandt, Markus; Turella, Paola; Antonini, Giovanni; Federici, Giorgio; Giansanti, Francesco; Stella, Lorenzo; Lo Bello, Mario; Caccuri, Anna Maria; Ricci, Giorgio

2005-07-15

Binding and catalytic properties of glutathione S-transferase from Plasmodium falciparum (PfGST) have been studied by means of fluorescence, steady state and pre-steady state kinetic experiments, and docking simulations. This enzyme displays a peculiar reversible low-high affinity transition, never observed in other GSTs, which involves the G-site and shifts the apparent K(D) for glutathione (GSH) from 200 to 0.18 mM. The transition toward the high affinity conformation is triggered by the simultaneous binding of two GSH molecules to the dimeric enzyme, and it is manifested as an uncorrected homotropic behavior, termed "pseudo-cooperativity." The high affinity enzyme is able to activate GSH, lowering its pK(a) value from 9.0 to 7.0, a behavior similar to that found in all known GSTs. Using 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, this enzyme reveals a potential optimized mechanism for the GSH conjugation but a low catalytic efficiency mainly due to a very low affinity for this co-substrate. Conversely, PfGST efficiently binds one molecule of hemin/monomer. The binding is highly cooperative (n(H) = 1.8) and occurs only when GSH is bound to the enzyme. The thiolate of GSH plays a crucial role in the intersubunit communication because no cooperativity is observed when S-methylglutathione replaces GSH. Docking simulations suggest that hemin binds to a pocket leaning into both the G-site and the H-site. The iron is coordinated by the amidic nitrogen of Asn-115, and the two carboxylate groups are in electrostatic interaction with the epsilon-amino group of Lys-15. Kinetic and structural data suggest that PfGST evolved by optimizing its binding property with the parasitotoxic hemin rather than its catalytic efficiency toward toxic electrophilic compounds.

Collective strategy for obstacle navigation during cooperative transport by ants.

PubMed

McCreery, Helen F; Dix, Zachary A; Breed, Michael D; Nagpal, Radhika

2016-11-01

Group cohesion and consensus have primarily been studied in the context of discrete decisions, but some group tasks require making serial decisions that build on one another. We examine such collective problem solving by studying obstacle navigation during cooperative transport in ants. In cooperative transport, ants work together to move a large object back to their nest. We blocked cooperative transport groups of Paratrechina longicornis with obstacles of varying complexity, analyzing groups' trajectories to infer what kind of strategy the ants employed. Simple strategies require little information, but more challenging, robust strategies succeed with a wider range of obstacles. We found that transport groups use a stochastic strategy that leads to efficient navigation around simple obstacles, and still succeeds at difficult obstacles. While groups navigating obstacles preferentially move directly toward the nest, they change their behavior over time; the longer the ants are obstructed, the more likely they are to move away from the nest. This increases the chance of finding a path around the obstacle. Groups rapidly changed directions and rarely stalled during navigation, indicating that these ants maintain consensus even when the nest direction is blocked. Although some decisions were aided by the arrival of new ants, at many key points, direction changes were initiated within the group, with no apparent external cause. This ant species is highly effective at navigating complex environments, and implements a flexible strategy that works for both simple and more complex obstacles. © 2016. Published by The Company of Biologists Ltd.

Reconsidering the "Good Divorce"

PubMed

Amato, Paul R; Kane, Jennifer B; James, Spencer

2011-12-01

This study attempted to assess the notion that a "good divorce" protects children from the potential negative consequences of marital dissolution. A cluster analysis of data on postdivorce parenting from 944 families resulted in three groups: cooperative coparenting, parallel parenting, and single parenting. Children in the cooperative coparenting (good divorce) cluster had the smallest number of behavior problems and the closest ties to their fathers. Nevertheless, children in this cluster did not score significantly better than other children on 10 additional outcomes. These findings provide only modest support for the good divorce hypothesis.

Reconsidering the “Good Divorce”

PubMed Central

Amato, Paul R.; Kane, Jennifer B.; James, Spencer

2011-01-01

This study attempted to assess the notion that a “good divorce” protects children from the potential negative consequences of marital dissolution. A cluster analysis of data on postdivorce parenting from 944 families resulted in three groups: cooperative coparenting, parallel parenting, and single parenting. Children in the cooperative coparenting (good divorce) cluster had the smallest number of behavior problems and the closest ties to their fathers. Nevertheless, children in this cluster did not score significantly better than other children on 10 additional outcomes. These findings provide only modest support for the good divorce hypothesis. PMID:22125355

Constant pH simulations of pH responsive polymers

NASA Astrophysics Data System (ADS)

Sharma, Arjun; Smith, J. D.; Walters, Keisha B.; Rick, Steven W.

2016-12-01

Polyacidic polymers can change structure over a narrow range of pH in a competition between the hydrophobic effect, which favors a compact state, and electrostatic repulsion, which favors an extended state. Constant pH molecular dynamics computer simulations of poly(methacrylic acid) reveal that there are two types of structural changes, one local and one global, which make up the overall response. The local structural response depends on the tacticity of the polymer and leads to different cooperative effects for polymers with different stereochemistries, demonstrating both positive and negative cooperativities.

Evaluation of Preventive Service to Families with a Prior History in Child Protective Services: A Comparison of Treatment as Usual to Trauma Systems Therapy

ERIC Educational Resources Information Center

Coombes, Margaret Lillian

2011-01-01

Children who are abused or maltreated may experience negative consequences or trauma symptoms that are not immediately apparent or may emerge over time. Child welfare interventions are intended to prevent future incidents of child abuse and decrease the negative outcomes that result from such traumatic events (English, et al., 2005; Herrenkohl &…

[Deficiencies and barriers of the cooperation between German general practitioners and occupational health physicians? A qualitative content analysis of focus groups].

PubMed

Moßhammer, Dirk; Natanzon, Iris; Manske, Ira; Grutschkowski, Philipp; Rieger, Monika A

2012-01-01

Given the high prevalence of work-associated health problems and the significance of work-related stress factors, cooperation between general practitioners (GPs) and occupational health physicians (OPs) is of particular interest to the healthcare system. Both groups of physicians have an important role to play in supporting prevention, rehabilitation and workplace reintegration. In Germany, however, cooperation between GPs and OPs is often lacking or suboptimal. In our study, we assessed relevant deficiencies in and barriers to this cooperation. Three focus groups were interviewed: GPs, OPs, and medical doctors working in both fields. Data were analysed according to the qualitative content analysis method of P. Mayring. Deficiencies such as lack of communication (e.g., opportunity to make phone calls), insufficient cooperation in regard to sick-leave and professional reintegration, lack of knowledge about the specialty and influence of OPs as well as about patients' working conditions in general. Barriers: Prejudices, competition, mistrust, fear of negative consequences for the patients, lack of legal regulations, or limited accessibility. Similar deficiencies and barriers were mentioned in all three focus groups. The data are helpful in understanding the interface between GPs and OPs in Germany to provide an informative basis for the development of quantitative research instruments for further analysis to improve cooperation. This is the basis for additional cooperation projects. Copyright © 2011. Published by Elsevier GmbH.

Volumetric and acoustical behaviour of sodium saccharin in aqueous system over temperature range (20.0-45.0)°C.

PubMed

Jamal, Muhammad Asghar; Rashad, Muhammad; Khosa, Muhammad Kaleem; Bhatti, Haq Nawaz

2015-04-15

Densities and ultrasonic velocity values for aqueous solutions of sodium saccharin (SS) has been measured as a function of concentration at 20.0-45.0 °C and atmospheric pressure using DSA-5000 M. The density and ultrasonic velocity values have been further used to calculate apparent molar volume, apparent specific volume, isentropic apparent molar compressibility and compressibility hydration numbers and reported. The values for apparent molar volume obtained at given temperatures showed negative deviations from Debye-Hückel limiting law and used as a direct measure of the ion-ion and ion-solvent interactions. The apparent specific volumes of the solute were calculated and it was found that these values of the investigated solutions lie on the borderline between the values reported for sweet substances. The sweetness response of the sweeteners is then explained in terms of their solution behaviours. Furthermore, the partial molar expansibility, its second derivative, (∂(2)V°/∂T(2)) as Hepler's constant and thermal expansion coefficient have been estimated. Copyright © 2014 Elsevier Ltd. All rights reserved.

Negatively Cooperative Binding of High Density Lipoprotein to the HDL Receptor SR-BI†

PubMed Central

Nieland, Thomas J.F.; Xu, Shangzhe; Penman, Marsha; Krieger, Monty

2011-01-01

Scavenger receptor class B, type I (SR-BI) is a high-density lipoprotein (HDL) receptor, which also binds low density lipoprotein (LDL), and mediates the cellular selective uptake of cholesteryl esters from lipoproteins. SR-BI also is a co-receptor for hepatitis C virus and a signaling receptor that regulates cell metabolism. Many investigators have reported that lipoproteins bind to SR-BI via a single class of independent (not interacting), high affinity binding sites (one site model). We have re-investigated the ligand concentration dependence of 125I-HDL binding to SR-BI and SR-BI-mediated specific uptake of [3H]CE from [3H]CE-HDL using an expanded range of ligand concentrations (<1 µg protein/ml, lower than previously reported). Scatchard and non-linear least squares model fitting analyses of the binding and uptake data were both inconsistent with a single class of independent binding sites binding univalent lipoprotein ligands. The data are best fit by models in which SR-BI has either two independent classes of binding sites, or one class of sites exhibiting negative cooperativity due to either classic allostery or ensemble effects (‘ lattice model’). Similar results were observed for LDL. Application of the ‘infinite dilution’ dissociation rate method established that the binding of 125I-HDL to SR-BI at 4 °C exhibits negative cooperativity. The unexpected complexity of the interactions of lipoproteins with SR-BI should be taken into account when interpreting the results of experiments that explore the mechanism(s) by which SR-BI mediates ligand binding, lipid transport and cell signaling. PMID:21254782

"Cooperative collapse" of the denatured state revealed through Clausius-Clapeyron analysis of protein denaturation phase diagrams.

PubMed

Tischer, Alexander; Machha, Venkata R; Rösgen, Jörg; Auton, Matthew

2018-02-19

Protein phase diagrams have a unique potential to identify the presence of additional thermodynamic states even when non-2-state character is not readily apparent from the experimental observables used to follow protein unfolding transitions. Two-state analysis of the von Willebrand factor A3 domain has previously revealed a discrepancy in the calorimetric enthalpy obtained from thermal unfolding transitions as compared with Gibbs-Helmholtz analysis of free energies obtained from the Linear Extrapolation Method (Tischer and Auton, Prot Sci 2013; 22(9):1147-60). We resolve this thermodynamic conundrum using a Clausius-Clapeyron analysis of the urea-temperature phase diagram that defines how ΔH and the urea m-value interconvert through the slope of c m versus T, (∂cm/∂T)=ΔH/(mT). This relationship permits the calculation of ΔH at low temperature from m-values obtained through iso-thermal urea denaturation and high temperature m-values from ΔH obtained through iso-urea thermal denaturation. Application of this equation uncovers sigmoid transitions in both cooperativity parameters as temperature is increased. Such residual thermal cooperativity of ΔH and the m-value confirms the presence of an additional state which is verified to result from a cooperative phase transition between urea-expanded and thermally-compact denatured states. Comparison of the equilibria between expanded and compact denatured ensembles of disulfide-intact and carboxyamidated A3 domains reveals that introducing a single disulfide crosslink does not affect the presence of the additional denatured state. It does, however, make a small thermodynamically favorable free energy (∼-13 ± 1 kJ/mol) contribution to the cooperative denatured state collapse transition as temperature is raised and urea concentration is lowered. The thermodynamics of this "cooperative collapse" of the denatured state retain significant compensations between the enthalpy and entropy contributions to the overall free energy. © 2018 Wiley Periodicals, Inc.

The Sus operon: a model system for starch uptake by the human gut Bacteroidetes

PubMed Central

Foley, Matthew H.; Cockburn, Darrell W.; Koropatkin, Nicole M.

2016-01-01

Resident bacteria in the densely populated human intestinal tract must efficiently compete for carbohydrate nutrition. The Bacteroidetes, a dominant bacterial phylum in the mammalian gut, encode a plethora of discrete polysaccharide utilization loci (PULs) that are selectively activated to facilitate glycan capture at the cell surface. The most well-studied PUL-encoded glycan-up-take system is the starch utilization system (Sus) of Bacteroides thetaiotaomicron. The Sus includes the requisite proteins for binding and degrading starch at the surface of the cell preceding oligosaccharide transport across the outer membrane for further depolymerization to glucose in the periplasm. All mammalian gut Bacteroidetes possess analogous Sus-like systems that target numerous diverse glycans. In this review, we discuss what is known about the eight Sus proteins of B. thetaiotaomicron that define the Sus-like paradigm of nutrient acquisition that is exclusive to the Gram-negative Bacteroidetes. We emphasize the well-characterized outer membrane proteins SusDEF and the α-amylase SusG, each of which have unique structural features that allow them to interact with starch on the cell surface. Despite the apparent redundancy in starch-binding sites among these proteins, each has a distinct role during starch catabolism. Additionally, we consider what is known about how these proteins dynamically interact and cooperate in the membrane and propose a model for the formation of the Sus outer membrane complex. PMID:27137179

The charcoal-degradation nexus: contested 'fuelscapes' in the sub-Saharan drylands of northern Kenya

NASA Astrophysics Data System (ADS)

Bergmann, Christoph; Petersen, Maike; Roden, Paul; Nüsser, Marcus

2017-04-01

Charcoal ranks amongst the most commercialized but least regulated commodities in sub-Saharan Africa. Despite its prevalence as an energy source for cooking and heating, localized environmental and livelihood impacts of charcoal production are poorly understood so far. The identified research deficit is amplified by widespread negative views of this activity as a poverty-driven cause of deforestation and land degradation. However, the charcoal-degradation nexus is apparently more complicated, not least because the extraction of biomass from already degraded woodlands can also be interpreted as an appropriate option under given management regimes. In order to better calibrate existing research agendas to site-specific geographies of charcoal production, we propose a re-conceptualization of such energy landscapes as 'fuelscapes' with complex material and social dimensions. The concept is tested with reference to a case study in Central Pokot, northern Kenya, where charcoal production only began in the early 1990's. Based on the assumption that the fine line between sustainable land management and degradation in dryland energy landscapes is not only highly variable but also increasingly contested, our study combines the knowledge input of different stakeholders with longitudinal time series of remote sensing data. Based on the results of our interdisciplinary analyses, we outline an integrated tool for the co-operative monitoring and management of prevailing degradation processes against the background of diversified livelihood activities in sub-Saharan drylands.

Reciprocity and the Emergence of Power Laws in Social Networks

NASA Astrophysics Data System (ADS)

Schnegg, Michael

Research in network science has shown that many naturally occurring and technologically constructed networks are scale free, that means a power law degree distribution emerges from a growth model in which each new node attaches to the existing network with a probability proportional to its number of links (= degree). Little is known about whether the same principles of local attachment and global properties apply to societies as well. Empirical evidence from six ethnographic case studies shows that complex social networks have significantly lower scaling exponents γ ~ 1 than have been assumed in the past. Apparently humans do not only look for the most prominent players to play with. Moreover cooperation in humans is characterized through reciprocity, the tendency to give to those from whom one has received in the past. Both variables — reciprocity and the scaling exponent — are negatively correlated (r = -0.767, sig = 0.075). If we include this effect in simulations of growing networks, degree distributions emerge that are much closer to those empirically observed. While the proportion of nodes with small degrees decreases drastically as we introduce reciprocity, the scaling exponent is more robust and changes only when a relatively large proportion of attachment decisions follow this rule. If social networks are less scale free than previously assumed this has far reaching implications for policy makers, public health programs and marketing alike.

Population dynamics of obligate cooperators

PubMed Central

Courchamp, F.; Grenfell, B.; Clutton-Brock, T.

1999-01-01

Obligate cooperative breeding species demonstrate a high rate of group extinction, which may be due to the existence of a critical number of helpers below which the group cannot subsist. Through a simple model, we study the population dynamics of obligate cooperative breeding species, taking into account the existence of a lower threshold below which the instantaneous growth rate becomes negative. The model successively incorporates (i) a distinction between species that need helpers for reproduction, survival or both, (ii) the existence of a migration rate accounting for dispersal, and (iii) stochastic mortality to simulate the effects of random catastrophic events. Our results suggest that the need for a minimum number of helpers increases the risk of extinction for obligate cooperative breeding species. The constraint imposed by this threshold is higher when helpers are needed for reproduction only or for both reproduction and survival. By driving them below this lower threshold, stochastic mortality of lower amplitude and/or lower frequency than for non-cooperative breeders may be sufficient to cause the extinction of obligate cooperative breeding groups. Migration may have a buffering effect only for groups where immigration is higher than emigration; otherwise (when immigrants from nearby groups are not available) it lowers the difference between actual group size and critical threshold, thereby constituting a higher constraint.

On the flexibility of social source memory: a test of the emotional incongruity hypothesis.

PubMed

Bell, Raoul; Buchner, Axel; Kroneisen, Meike; Giang, Trang

2012-11-01

A popular hypothesis in evolutionary psychology posits that reciprocal altruism is supported by a cognitive module that helps cooperative individuals to detect and remember cheaters. Consistent with this hypothesis, a source memory advantage for faces of cheaters (better memory for the cheating context in which these faces were encountered) was observed in previous studies. Here, we examined whether positive or negative expectancies would influence source memory for cheaters and cooperators. A cooperation task with virtual opponents was used in Experiments 1 and 2. Source memory for the emotionally incongruent information was enhanced relative to the congruent information: In Experiment 1, source memory was best for cheaters with likable faces and for cooperators with unlikable faces; in Experiment 2, source memory was better for smiling cheater faces than for smiling cooperator faces, and descriptively better for angry cooperator faces than for angry cheater faces. Experiments 3 and 4 showed that the emotional incongruity effect generalizes to 3rd-party reputational information (descriptions of cheating and trustworthy behavior). The results are inconsistent with the assumption of a highly specific cheater detection module. Focusing on expectancy-incongruent information may represent a more efficient, general, and hence more adaptive memory strategy for remembering exchange-relevant information than focusing only on cheaters.

Enzymatic properties of separated isozymes of the Na,K-ATPase. Substrate affinities, kinetic cooperativity, and ion transport stoichiometry.

PubMed

Sweadner, K J

1985-09-25

There are two isozymes of the Na,K-ATPase, which can be purified separately from rat renal medulla and brainstem axolemma. Here the basic kinetic properties of the two Na,K-ATPases have been compared in conditions permitting enzyme turnover. The two isozymes are half-maximally activated at different concentrations of ATP, the axolemma Na,K-ATPase having the higher affinity. They are half-maximally activated by Na+ and K+ at very similar concentrations but show differences in cooperativity toward Na+. The affinities of both isozymes for ATP and Na+ are affected in a qualitatively similar way by variations in the concentration of K+. Both isozymes transport 22Na+ and 42K+ in a ratio close to 3:2 in artificial lipid vesicles. The two isozymes differ most strikingly in the inhibition of ATPase activity by ouabain. The axolemma Na,K-ATPase has a high affinity for ouabain with positive cooperativity, while the renal medulla Na,K-ATPase has a lower affinity with negative cooperativity. It is likely that the cooperativity differences are due to kinetic effects, reflecting different rates of conformation transitions during enzyme turnover. The functional result of the contrasting cooperativities is that the difference in sensitivity to ouabain is amplified.

Heterogeneity of allocation promotes cooperation in public goods games

NASA Astrophysics Data System (ADS)

Lei, Chuang; Wu, Te; Jia, Jian-Yuan; Cong, Rui; Wang, Long

2010-11-01

We investigate the effects of heterogeneous investment and distribution on the evolution of cooperation in the context of the public goods games. To do this, we develop a simple model in which each individual allocates differing funds to his direct neighbors based upon their difference in connectivity, because of the heterogeneity of real social ties. This difference is characterized by the weight of the link between paired individuals, with an adjustable parameter precisely controlling the heterogeneous level of ties. By numerical simulations, it is found that allocating both too much and too little funds to diverse neighbors can remarkably improve the cooperation level. However, there exists a worst mode of funds allocation leading to the most unfavorable cooperation induced by the moderate values of the parameter. In order to better reveal the potential causes behind these nontrivial phenomena we probe the microscopic characteristics including the average payoff and the cooperator density for individuals of different degrees. It demonstrates rather different dynamical behaviors between the modes of these two types of cooperation promoter. Besides, we also investigate the total link weights of individuals numerically and theoretically for negative values of the parameter, and conclude that the payoff magnitude of middle-degree nodes plays a crucial role in determining the cooperators’ fate.

Incentives for cooperation in quality improvement among hospitals--the impact of the reimbursement system.

PubMed

Kesteloot, K; Voet, N

1998-12-01

Up to now, few analytical models have studied the incentives for cooperation in quality improvements among hospitals. Only those dealing with reimbursement systems have shown that, from the point of view of individual or competing hospitals, retrospective reimbursement is more likely to encourage quality improvements than prospective financing, while the reverse holds for efficiency improvements. This paper studies the incentives to improve the quality of hospital care, in an analytical model, taking into account the possibility of cooperative agreements, price besides non-price (quality) competition and quality improvements that may simultaneously increase demand, increase or reduce costs and spill over to rival hospitals. In this setting quality improvement efforts rise with the rate of prospective reimbursement, while the impact of the rate of retrospective reimbursement is ambiguous, but likely to be negative for quality improvements that are highly cost-reducting and create large spillovers. Cooperation may lead to more or less quality improvement than non-cooperative conduct, depending on the magnitude of spillovers and the degree of product market competition, relative to the net effect of quality on profits and the share of costs that is reimbursed retrospectively. Finally, the stability of cooperative agreements, supported by grim trigger strategies, is shown to depend upon exactly the opposite interaction between these factors.

Representation of economic preferences in the structure and function of the amygdala and prefrontal cortex

PubMed Central

Fermin, Alan S. R.; Sakagami, Masamichi; Kiyonari, Toko; Li, Yang; Matsumoto, Yoshie; Yamagishi, Toshio

2016-01-01

Social value orientations (SVOs) are economic preferences for the distribution of resources – prosocial individuals are more cooperative and egalitarian than are proselfs. Despite the social and economic implications of SVOs, no systematic studies have examined their neural correlates. We investigated the amygdala and dorsolateral prefrontal cortex (DLPFC) structures and functions in prosocials and proselfs by functional magnetic resonance imaging and evaluated cooperative behavior in the Prisoner’s Dilemma game. We found for the first time that amygdala volume was larger in prosocials and positively correlated with cooperation, while DLPFC volume was larger in proselfs and negatively correlated with cooperation. Proselfs’ decisions were marked by strong DLPFC and weak amygdala activity, and prosocials’ decisions were marked by strong amygdala activity, with the DLPFC signal increasing only in defection. Our findings suggest that proselfs’ decisions are controlled by DLPFC-mediated deliberative processes, while prosocials’ decisions are initially guided by automatic amygdala processes. PMID:26876988

Cooperative communication within and between single nanocatalysts

NASA Astrophysics Data System (ADS)

Zou, Ningmu; Zhou, Xiaochun; Chen, Guanqun; Andoy, Nesha May; Jung, Won; Liu, Guokun; Chen, Peng

2018-06-01

Enzymes often show catalytic allostery in which reactions occurring at different sites communicate cooperatively over distances of up to a few nanometres. Whether such effects can occur with non-biological nanocatalysts remains unclear, even though these nanocatalysts can undergo restructuring and molecules can diffuse over catalyst surfaces. Here we report that phenomenologically similar, but mechanistically distinct, cooperative effects indeed exist for nanocatalysts. Using spatiotemporally resolved single-molecule catalysis imaging, we find that catalytic reactions on a single Pd or Au nanocatalyst can communicate with each other, probably via hopping of positively charged holes on the catalyst surface, over 102 nanometres and with a temporal memory of 101 to 102 seconds, giving rise to positive cooperativity among its surface active sites. Similar communication is also observed between individual nanocatalysts, however it operates via a molecular diffusion mechanism involving negatively charged product molecules, and its communication distance is many micrometres. Generalization of these long-range intra- and interparticle catalytic communication mechanisms may introduce a novel conceptual framework for understanding nanoscale catalysis.

The concepts of asymmetric and symmetric power can help resolve the puzzle of altruistic and cooperative behaviour.

PubMed

Phillips, Tim

2018-02-01

Evolutionary theory predicts competition in nature yet altruistic and cooperative behaviour appears to reduce the ability to compete in order to help others compete better. This evolutionary puzzle is usually explained by kin selection where close relatives perform altruistic and cooperative acts to help each other and by reciprocity theory (i.e. direct, indirect and generalized reciprocity) among non-kin. Here, it is proposed that the concepts of asymmetry and symmetry in power and dominance are critical if we are ever to resolve the puzzle of altruism and cooperation towards non-kin. Asymmetry in power and dominance is likely to emerge under competition in nature as individuals strive to gain greater access to the scarce resources needed to survive and reproduce successfully. Yet asymmetric power presents serious problems for reciprocity theory in that a dominant individual faces a temptation to cheat in interactions with subordinates that is likely to far outweigh any individual selective benefits gained through reciprocal mechanisms. Furthermore, action taken by subordinates to deter non-reciprocation by dominants is likely to prove prohibitively costly to their fitness, making successful enforcement of reciprocal mechanisms unlikely. It is also argued here that many apparently puzzling forms of cooperation observed in nature (e.g. cooperative breeding in which unrelated subordinates help dominants to breed) might be best explained by asymmetry in power and dominance. Once it is recognized that individuals in these cooperative interactions are subject to the constraints and opportunities imposed on them by asymmetric power then they can be seen as pursuing a 'least bad' strategy to promote individual fitness - one that is nevertheless consistent with evolutionary theory. The concept of symmetric power also provides important insights. It can inhibit reciprocal mechanisms in the sense that symmetric power makes it easier for a cheat to appropriate common resources while incurring fewer penalties. Nevertheless under certain restrictive conditions, symmetric power is seen as likely to promote direct reciprocity through 'tit for tat'. © 2017 Cambridge Philosophical Society.

Cooperative action of multiple cis-acting elements is required for N-myc expression in branchial arches: specific contribution of GATA3.

PubMed

Potvin, Eric; Beuret, Laurent; Cadrin-Girard, Jean-François; Carter, Marcelle; Roy, Sophie; Tremblay, Michel; Charron, Jean

2010-11-01

The precise expression of the N-myc proto-oncogene is essential for normal mammalian development, whereas altered N-myc gene regulation is known to be a determinant factor in tumor formation. Using transgenic mouse embryos, we show that N-myc sequences from kb -8.7 to kb +7.2 are sufficient to reproduce the N-myc embryonic expression profile in developing branchial arches and limb buds. These sequences encompass several regulatory elements dispersed throughout the N-myc locus, including an upstream limb bud enhancer, a downstream somite enhancer, a branchial arch enhancer in the second intron, and a negative regulatory element in the first intron. N-myc expression in the limb buds is under the dominant control of the limb bud enhancer. The expression in the branchial arches necessitates the interplay of three regulatory domains. The branchial arch enhancer cooperates with the somite enhancer region to prevent an inhibitory activity contained in the first intron. The characterization of the branchial arch enhancer has revealed a specific role of the transcription factor GATA3 in the regulation of N-myc expression. Together, these data demonstrate that correct N-myc developmental expression is achieved via cooperation of multiple positive and negative regulatory elements.

Effects of oxytocin and vasopressin on the neural response to unreciprocated cooperation within brain regions involved in stress and anxiety in men and women.

PubMed

Chen, Xu; Hackett, Patrick D; DeMarco, Ashley C; Feng, Chunliang; Stair, Sabrina; Haroon, Ebrahim; Ditzen, Beate; Pagnoni, Giuseppe; Rilling, James K

2016-06-01

Anxiety disorders are characterized by hyperactivity in both the amygdala and the anterior insula. Interventions that normalize activity in these areas may therefore be effective in treating anxiety disorders. Recently, there has been significant interest in the potential use of oxytocin (OT), as well as vasopressin (AVP) antagonists, as treatments for anxiety disorders. In this double-blind, placebo-controlled, pharmaco- fMRI study, 153 men and 151 women were randomized to treatment with either 24 IU intranasal OT, 20 IU intranasal AVP, or placebo and imaged with fMRI as they played the iterated Prisoner's Dilemma game with same-sex human and computer partners. In men, OT attenuated the fMRI response to unreciprocated cooperation (CD), a negative social interaction, within the amygdala and anterior insula. This effect was specific to interactions with human partners. In contrast, among women, OT unexpectedly attenuated the amygdala and anterior insula response to unreciprocated cooperation from computer but not human partners. Among women, AVP did not significantly modulate the response to unreciprocated cooperation in either the amygdala or the anterior insula. However, among men, AVP attenuated the BOLD response to CD outcomes with human partners across a relatively large cluster including the amygdala and the anterior insula, which was contrary to expectations. Our results suggest that OT may decrease the stress of negative social interactions among men, whereas these effects were not found in women interacting with human partners. These findings support continued investigation into the possible efficacy of OT as a treatment for anxiety disorders.

Noise from implantable Cooper cable.

PubMed

Carrington, V; Zhou, L; Donaldson, N

2005-09-01

Cooper cable is made for implanted devices, usually for connection to stimulating electrodes. An experiment has been performed to see whether these cables would be satisfactory for recording electroneurogram (ENG) signals from cuffs. Four cables were subjected to continuous flexion at 2 Hz while submerged in saline. The cables were connected to a low-noise amplifier, and the noise was measured using a spectrum analyser. These cables had not fractured after 184 million flexions, and the noise in the neural band (500-5000 Hz) had not increased owing to age. Noise in the ENG band increased by less than 3 dB owing to the motion. A fifth, worn cable did fail during the experiment, the conductors becoming exposed to the saline, but this was only apparent by extra noise when the cable was in motion. After 184 million flexions, the four cables were given a more severe test: instead of being connected to the amplifier reference node, two of the four cores of each cable were connected to 18V batteries. Two of the cables were then noisier, but only when in motion, presumably because of leakage between cores. Cooper cables are excellent for transmitting neural signals alone; transmission in one cable of neural signals and power supplies should be avoided if possible.

Implicit bias in astronomy

NASA Astrophysics Data System (ADS)

Knezek, Patricia

2017-06-01

We all harbour subconscious expectations about people based on their apparent membership of groups, such as gender, ethnicity or age. Research shows that these expectations can lead us to undervalue some people's contributions, inhibiting their success and thus negatively impacting our entire field.

The Role of Cooperation and Information Exchange in Transnational River Basins: the Zambezi River case

NASA Astrophysics Data System (ADS)

Castelletti, A.; Giuliani, M.; Soncini-Sessa, R.

2012-12-01

The presence of multiple, institutionally independent but physically interconnected decision-makers is a distinctive features of many water resources systems, especially of transnational river basins. The adoption of a centralized approach to study the optimal operation of these systems, as mostly done in the water resources literature, is conceptually interesting to quantify the best achievable performance, but of little practical impact given the real political and institutional setting. Centralized management indeed assumes a cooperative attitude and full information exchange by the involved parties. However, when decision-makers belong to different countries or institutions, it is very likely that they act considering only their local objectives, producing global externalities that negatively impact on other objectives. In this work we adopt a Multi-Agent Systems framework, which naturally allows to represent a set of self-interested agents (decision-makers and/or stakeholders) acting in a distributed decision-making process. According to this agent-based approach, each agent represents a decision-maker, whose decisions are defined by an explicit optimization problem considering only the agent's local interests. In particular, this work assesses the role of information exchange and increasing level of cooperation among originally non-cooperative agents. The Zambezi River basin is used to illustrate the methodology: the four largest reservoirs in the basin (Ithezhithezhi, Kafue-Gorge, Kariba and Cahora Bassa) are mainly operated for maximizing the economic revenue from hydropower energy production with considerably negative effects on the aquatic ecosystem in the Zambezi delta due to the alteration of the natural flow regime. We comparatively analyse the ideal centralized solution and the current situation where all the decision-makers act independently and non-cooperatively. Indeed, although a new basin-level institution called Zambezi Watercourse Commission (ZAMCON) should be established in the next future, Zambia recently refused to sign and ratify the ZAMCON Protocol and the road toward a fully cooperative framework is still long. Results show that increasing levels of information exchange can help in mitigating the conflict generated by a non-cooperative setting as it allows the downstream agents, i.e. Mozambique country, to better adapt to the upstream management strategies. Furthermore, the role of information exchange depends on the considered objectives and it is particularly relevant for environmental interests.

Cofoundress relatedness and group productivity in colonies of social Dunatothrips (Insecta: Thysanoptera) on Australian Acacia

PubMed Central

Bono, Jeremy M.; Crespi, Bernard J.

2015-01-01

Facultative joint colony founding by social insects provides opportunities to analyze the roles of genetic and ecological factors in the evolution of cooperation. Although cooperative nesting is observed in range of social insect taxa, the most detailed studies of this behavior have been conducted with Hymenoptera (ants, bees, and wasps). Here, we show that foundress associations in the haplodiploid social thrips Dunatothrips aneurae (Insecta: Thysanoptera) are most often comprised of close relatives (sisters), though groups with unrelated foundresses are also found. Associations among relatives appear to be facilitated by limited female dispersal, which results in viscous population structure. In addition, we found that per capita productivity declined with increasing group size, sex ratios were female-biased, and some female offspring apparently remained in their natal domicile for some time following eclosion. D. aneurae thus exhibits a suite of similarities with eusocial Hymenoptera, providing evidence for the convergent evolution of associated social and life-history traits in Hymenoptera and Thysanoptera. PMID:26279604

Intergroup Conflict and Rational Decision Making

PubMed Central

Martínez-Tur, Vicente; Peñarroja, Vicente; Serrano, Miguel A.; Hidalgo, Vanesa; Moliner, Carolina; Salvador, Alicia; Alacreu-Crespo, Adrián; Gracia, Esther; Molina, Agustín

2014-01-01

The literature has been relatively silent about post-conflict processes. However, understanding the way humans deal with post-conflict situations is a challenge in our societies. With this in mind, we focus the present study on the rationality of cooperative decision making after an intergroup conflict, i.e., the extent to which groups take advantage of post-conflict situations to obtain benefits from collaborating with the other group involved in the conflict. Based on dual-process theories of thinking and affect heuristic, we propose that intergroup conflict hinders the rationality of cooperative decision making. We also hypothesize that this rationality improves when groups are involved in an in-group deliberative discussion. Results of a laboratory experiment support the idea that intergroup conflict –associated with indicators of the activation of negative feelings (negative affect state and heart rate)– has a negative effect on the aforementioned rationality over time and on both group and individual decision making. Although intergroup conflict leads to sub-optimal decision making, rationality improves when groups and individuals subjected to intergroup conflict make decisions after an in-group deliberative discussion. Additionally, the increased rationality of the group decision making after the deliberative discussion is transferred to subsequent individual decision making. PMID:25461384

Intergroup conflict and rational decision making.

PubMed

Martínez-Tur, Vicente; Peñarroja, Vicente; Serrano, Miguel A; Hidalgo, Vanesa; Moliner, Carolina; Salvador, Alicia; Alacreu-Crespo, Adrián; Gracia, Esther; Molina, Agustín

2014-01-01

The literature has been relatively silent about post-conflict processes. However, understanding the way humans deal with post-conflict situations is a challenge in our societies. With this in mind, we focus the present study on the rationality of cooperative decision making after an intergroup conflict, i.e., the extent to which groups take advantage of post-conflict situations to obtain benefits from collaborating with the other group involved in the conflict. Based on dual-process theories of thinking and affect heuristic, we propose that intergroup conflict hinders the rationality of cooperative decision making. We also hypothesize that this rationality improves when groups are involved in an in-group deliberative discussion. Results of a laboratory experiment support the idea that intergroup conflict -associated with indicators of the activation of negative feelings (negative affect state and heart rate)- has a negative effect on the aforementioned rationality over time and on both group and individual decision making. Although intergroup conflict leads to sub-optimal decision making, rationality improves when groups and individuals subjected to intergroup conflict make decisions after an in-group deliberative discussion. Additionally, the increased rationality of the group decision making after the deliberative discussion is transferred to subsequent individual decision making.

Inequity-aversion and relative kindness intention jointly determine the expenditure of effort in project teams.

PubMed

Han, Jiaojie; Rapoport, Amnon; Zhao, Rui

2017-01-01

The literature on team cooperation has neglected the effects of relative kindness intention on cooperation, which we measure by comparing the kindness intentions of an agent to her group members to the kindness shown by other members to this same agent. We argue that the agent's emotional reaction to material payoff inequity is not constant, but rather affected by her relative kindness intention. Then, we apply the model to team projects with multiple partners and investigate how inequity-aversion and relative kindness intention jointly influence team cooperation. We first consider the case of homogeneous agents, where their marginal productivity levels and technical capacities are the same, and then consider the case of heterogeneous agents, where their marginal productivity levels and technical capacities are not the same. Our results show that inequity-aversion has no effect on effort expenditure in the former case, but does affect it in the latter case. The consideration of relative kindness intention may impact the agents' optimal cooperative effort expenditure when their technical capacities are different. In addition, it is beneficial for team cooperation, and might not only reduce the negative impact but also enhance the positive impact of inequity-aversion on the agents' effort expenditures.

Relationship between traditional games and the intensity of emotions experienced by participants.

PubMed

Lavega, Pere; Alonso, José I; Etxebeste, Joseba; Lagardera, Francisco; March, Jaume

2014-12-01

The aims of this study were to analyze the intensity of emotions (positive, negative, or ambiguous) produced when players took part in traditional games with a different social structure and to examine the explanations given by those participants for these emotional experiences. Participants (N = 556) were recruited from 4 Spanish universities. After taking part in each of the games, they were asked to complete the Games and Emotions Questionnaire to indicate the intensity of their emotional experiences and to explain what, in their view, had led to the strongest emotion felt. The application of a mixed-methods approach identified statistically significant differences in relation to 3 variables. These were (a) the type of emotion, (b) motor domain, and (c) type of result (win, loss, and noncompetitive). The intensity of positive emotions was higher in cooperative games and lower in individual games. Comments referring to negative emotions were more frequent as the social structure of games became more complex (minimal presence of individual games and predominance of cooperation-opposition games). Winning was associated with the highest intensity ratings of positive and ambiguous emotions, whereas being defeated produced the highest values for negative emotions. The intensity ratings for negative emotions were lower in noncompetitive games than in games where players lost. The results confirm that traditional games can play a key role in relation to the emotional facets of physical education.

The news on smoking: newspaper coverage of smoking and health in Australia, 1987-88.

PubMed Central

Chapman, S

1989-01-01

All newspaper articles (n = 1601) mentioning tobacco or smoking drawn from a 12-month census of 30 Australian capital city newspapers in 1987-88 were coded for content, "slant," and apparent origin. Overall, 62 percent of articles were positive in their orientation toward smoking control objectives, 17 percent were negative, and 21 percent were neutral. Newspapers owned by Rupert Murdoch published 55.7 percent positive and 23.7 percent negative articles compared to 68.0 percent positive and 13.7 percent negative articles in the other large chain of Australian newspapers. PMID:2782518

Elevated surface temperature depresses survival of banner-tailed kangaroo rats: will climate change cook a desert icon?

PubMed

Moses, Martin R; Frey, Jennifer K; Roemer, Gary W

2012-01-01

Modest increases in global temperature have been implicated in causing population extirpations and range shifts in taxa inhabiting colder environs and in ectotherms whose thermoregulation is more closely tied to environmental conditions. Many arid-adapted endotherms already experience conditions at their physiological limits, so it is conceivable that they could be similarly affected by warming temperatures. We explored how climatic variables might influence the apparent survival of the banner-tailed kangaroo rat (Dipodomys spectabilis), a rodent endemic to the Chihuahuan Desert of North America and renowned for its behavioral and physiological adaptations to arid environments. Relative variable weight, strength of variable relationships, and other criteria indicated that summer, diurnal land surface temperature (SD_LST) was the primary environmental driver of apparent survival in these arid-adapted rodents. Higher temperatures had a negative effect on apparent survival, which ranged from 0.15 (SE = 0.04) for subadults to 0.50 (SE = 0.07) for adults. Elevated SD_LST may negatively influence survival through multiple pathways, including increased water loss and energy expenditure that could lead to chronic stress and/or hyperthermia that could cause direct mortality. Land surface temperatures are predicted to increase by as much 6.5°C by 2099, reducing apparent survival of adults to ~0.15 in some regions of the species' range, possibly causing a shift in their distribution. The relationship between SD_LST and survival suggests a mechanism whereby physiological tolerances are exceeded resulting in a reduction to individual fitness that may ultimately cause a shift in the species' range over time.

Interstate 80 high-occupancy vehicle lane project : initial study, proposed mitigated negative declaration.

DOT National Transportation Integrated Search

2006-12-01

The Solano Transportation Authority (STA) in cooperation with the California Department of : Transportation (Caltrans) proposes to construct high-occupancy vehicle (HOV) lanes within the : median of Interstate 80 (I-80) between Red Top Road and Air B...

[Modern nursing work management trends: the case of cooperative companies].

PubMed

Guimarães, Raphael Mendonça; Muzi, Camila Drumond; Mauro, Maria Yvone Chaves

2004-01-01

This article introduces the issue of nursing work management from a theoretical and conceptual perspective by raising some implications for the management of organizations, as well as its impact on work relationships and, consequently, on the worker's health. The main results about ways and modalities of cooperative companies bring about the consideration that proposals of positive changes in the category run contrary to progress. Indecent work conditions, poor quality assistance and low compensation make up the main negative factors in this work process. Therefore, it is urgent to resume the discussion of what one expects from nursing for the future.

Apparent ruminal synthesis of B vitamins in lactating dairy cows fed diets with different forage-to-concentrate ratios.

PubMed

Seck, M; Linton, J A Voelker; Allen, M S; Castagnino, D S; Chouinard, P Y; Girard, C L

2017-03-01

Effects of the forage-to-concentrate ratio on apparent ruminal synthesis of thiamine, riboflavin, niacin, vitamin B 6 , folates, and vitamin B 12 were evaluated in an experiment using 14 ruminally and duodenally cannulated Holstein cows. The experiment was a crossover design with two 15-d treatment periods and a 14-d preliminary period in which cows were fed a diet intermediate in composition between the treatment diets. Treatments were diets containing low-forage (44.8% forage, 32.8% starch, 24.4% neutral detergent fiber) or high-forage (61.4% forage, 22.5% starch, 30.7% neutral detergent fiber) concentrations. Both diets were formulated with different proportions of the same ingredients. Concentrations of B vitamins were analyzed in feed and duodenal digesta. Apparent ruminal synthesis of each B vitamin was calculated as the duodenal flow minus the intake. The high-forage diet had the highest concentrations of riboflavin, niacin, vitamin B 6 , and folates, whereas the low-forage diet had the highest thiamine concentration. Vitamin B 12 in the diets was under the level of detection. Consequently, despite a reduction in dry matter intake when the cows were fed the high-forage diet, increasing dietary forage concentration increased or tended to increase intakes of riboflavin, niacin, and vitamin B 6 but reduced thiamine and folate intakes. Increasing dietary forage concentration reduced apparent ruminal degradation of thiamine and apparent ruminal synthesis of riboflavin, niacin, and folates and increased ruminal degradation of vitamin B 6 , but had no effect on ruminal synthesis of vitamin B 12 . As a consequence, increasing the forage-to-concentrate ratio had no effect on the amounts of thiamine, riboflavin, and vitamin B 12 reaching the small intestine but decreased the amounts of niacin, vitamin B 6 , and folates available for absorption. Apparent ruminal syntheses of riboflavin, niacin, folates, and vitamin B 12 were correlated positively with the amount of starch digested in the rumen and duodenal flow of microbial N, whereas these correlations were negative for thiamine. Apparent ruminal syntheses of thiamine and vitamin B 6 were negatively correlated with their respective intakes, whereas folate intake was positively correlated with its synthesis in the rumen. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Reciprocity and the Tragedies of Maintaining and Providing the Commons.

PubMed

Gächter, Simon; Kölle, Felix; Quercia, Simone

2017-09-01

Social cooperation often requires collectively beneficial but individually costly restraint to maintain a public good1-4, or it needs costly generosity to create one1,5. Status quo effects6 predict that maintaining a public good is easier than providing a new one. Here we show experimentally and with simulations that even under identical incentives, low levels of cooperation (the 'tragedy of the commons'2) are systematically more likely in Maintenance than Provision. Across three series of experiments, we find that strong and weak positive reciprocity, known to be fundamental tendencies underpinning human cooperation7-10, are substantially diminished under Maintenance compared to Provision. As we show in a fourth experiment, the opposite holds for negative reciprocity ('punishment'). Our findings suggest that incentives to avoid the 'tragedy of the commons' need to contend with dilemma-specific reciprocity.

Cooperative effect of random and time-periodic coupling strength on synchronization transitions in one-way coupled neural system: mean field approach.

PubMed

Jiancheng, Shi; Min, Luo; Chusheng, Huang

2017-08-01

The cooperative effect of random coupling strength and time-periodic coupling strengh on synchronization transitions in one-way coupled neural system has been investigated by mean field approach. Results show that cooperative coupling strength (CCS) plays an active role for the enhancement of synchronization transitions. There exist an optimal frequency of CCS which makes the system display the best CCS-induced synchronization transitions, a critical frequency of CCS which can not further affect the CCS-induced synchronization transitions, and a critical amplitude of CCS which can not occur the CCS-induced synchronization transitions. Meanwhile, noise intensity plays a negative role for the CCS-induced synchronization transitions. Furthermore, it is found that the novel CCS amplitude-induced synchronization transitions and CCS frequency-induced synchronization transitions are found.

Collaboration between general practitioners and occupational physicians: a comparison of the results of two national surveys in France.

PubMed

Verger, Pierre; Ménard, Colette; Richard, Jean-Baptiste; Demortière, Gérard; Beck, François

2014-02-01

To study the perceptions that general practitioners (GPs) and occupational physicians (OPs) have of GPs' role in occupational health and their willingness to work together to prevent the exclusion of patients with disabilities from the workplace. Cross-sectional telephone survey of two randomly selected national samples of GPs and OPs was conducted. The majority of GPs and OPs are in favor of cooperation, especially to prevent exclusion from the workplace. However, some GPs lack trust in OPs' independence, an attitude associated negatively with the practice of GP referral to OPs to anticipate disability-related problems likely to occur when returning to work after a prolonged sick leave. There are some barriers to cooperation, on the part of both OPs and GPs. Initiatives are needed to encourage cooperation between these two types of physicians.

Selfish play increases during high-stakes NBA games and is rewarded with more lucrative contracts.

PubMed

Uhlmann, Eric Luis; Barnes, Christopher M

2014-01-01

High-stakes team competitions can present a social dilemma in which participants must choose between concentrating on their personal performance and assisting teammates as a means of achieving group objectives. We find that despite the seemingly strong group incentive to win the NBA title, cooperative play actually diminishes during playoff games, negatively affecting team performance. Thus team cooperation decreases in the very high stakes contexts in which it is most important to perform well together. Highlighting the mixed incentives that underlie selfish play, personal scoring is rewarded with more lucrative future contracts, whereas assisting teammates to score is associated with reduced pay due to lost opportunities for personal scoring. A combination of misaligned incentives and psychological biases in performance evaluation bring out the "I" in "team" when cooperation is most critical.

Selfish Play Increases during High-Stakes NBA Games and Is Rewarded with More Lucrative Contracts

PubMed Central

Uhlmann, Eric Luis; Barnes, Christopher M.

2014-01-01

High-stakes team competitions can present a social dilemma in which participants must choose between concentrating on their personal performance and assisting teammates as a means of achieving group objectives. We find that despite the seemingly strong group incentive to win the NBA title, cooperative play actually diminishes during playoff games, negatively affecting team performance. Thus team cooperation decreases in the very high stakes contexts in which it is most important to perform well together. Highlighting the mixed incentives that underlie selfish play, personal scoring is rewarded with more lucrative future contracts, whereas assisting teammates to score is associated with reduced pay due to lost opportunities for personal scoring. A combination of misaligned incentives and psychological biases in performance evaluation bring out the “I” in “team” when cooperation is most critical. PMID:24763384

Chimpanzees are vengeful but not spiteful

PubMed Central

Jensen, Keith; Call, Josep; Tomasello, Michael

2007-01-01

People are willing to punish others at a personal cost, and this apparently antisocial tendency can stabilize cooperation. What motivates humans to punish noncooperators is likely a combination of aversion to both unfair outcomes and unfair intentions. Here we report a pair of studies in which captive chimpanzees (Pan troglodytes) did not inflict costs on conspecifics by knocking food away if the outcome alone was personally disadvantageous but did retaliate against conspecifics who actually stole the food from them. Like humans, chimpanzees retaliate against personally harmful actions, but unlike humans, they are indifferent to simply personally disadvantageous outcomes and are therefore not spiteful. PMID:17644612

Joint inversion of apparent resistivity and seismic surface and body wave data

NASA Astrophysics Data System (ADS)

Garofalo, Flora; Sauvin, Guillaume; Valentina Socco, Laura; Lecomte, Isabelle

2013-04-01

A novel inversion algorithm has been implemented to jointly invert apparent resistivity curves from vertical electric soundings, surface wave dispersion curves, and P-wave travel times. The algorithm works in the case of laterally varying layered sites. Surface wave dispersion curves and P-wave travel times can be extracted from the same seismic dataset and apparent resistivity curves can be obtained from continuous vertical electric sounding acquisition. The inversion scheme is based on a series of local 1D layered models whose unknown parameters are thickness h, S-wave velocity Vs, P-wave velocity Vp, and Resistivity R of each layer. 1D models are linked to surface-wave dispersion curves and apparent resistivity curves through classical 1D forward modelling, while a 2D model is created by interpolating the 1D models and is linked to refracted P-wave hodograms. A priori information can be included in the inversion and a spatial regularization is introduced as a set of constraints between model parameters of adjacent models and layers. Both a priori information and regularization are weighted by covariance matrixes. We show the comparison of individual inversions and joint inversion for a synthetic dataset that presents smooth lateral variations. Performing individual inversions, the poor sensitivity to some model parameters leads to estimation errors up to 62.5 %, whereas for joint inversion the cooperation of different techniques reduces most of the model estimation errors below 5% with few exceptions up to 39 %, with an overall improvement. Even though the final model retrieved by joint inversion is internally consistent and more reliable, the analysis of the results evidences unacceptable values of Vp/Vs ratio for some layers, thus providing negative Poisson's ratio values. To further improve the inversion performances, an additional constraint is added imposing Poisson's ratio in the range 0-0.5. The final results are globally improved by the introduction of this constraint further reducing the maximum error to 30 %. The same test was performed on field data acquired in a landslide-prone area close by the town of Hvittingfoss, Norway. Seismic data were recorded on two 160-m long profiles in roll-along mode using a 5-kg sledgehammer as source and 24 4.5-Hz vertical geophones with 4-m separation. First-arrival travel times were picked at every shot locations and surface wave dispersion curves extracted at 8 locations for each profile. 2D resistivity measurements were carried out on the same profiles using Gradient and Dipole-Dipole arrays with 2-m electrode spacing. The apparent resistivity curves were extracted at the same location as for the dispersion curves. The data were subsequently jointly inverted and the resulting model compared to individual inversions. Although models from both, individual and joint inversions are consistent, the estimation error is smaller for joint inversion, and more especially for first-arrival travel times. The joint inversion exploits different sensitivities of the methods to model parameters and therefore mitigates solution nonuniqueness and the effects of intrinsic limitations of the different techniques. Moreover, it produces an internally consistent multi-parametric final model that can be profitably interpreted to provide a better understanding of subsurface properties.

Negative cooperativity in binding of muscarinic receptor agonists and GDP as a measure of agonist efficacy

PubMed Central

Jakubík, J; Janíčková, H; El-Fakahany, EE; Doležal, V

2011-01-01

BACKGROUND AND PURPOSE Conventional determination of agonist efficacy at G-protein coupled receptors is measured by stimulation of guanosine-5′-γ−thiotriphosphate (GTPγS) binding. We analysed the role of guanosine diphosphate (GDP) in the process of activation of the M2 muscarinic acetylcholine receptor and provide evidence that negative cooperativity between agonist and GDP binding is an alternative measure of agonist efficacy. EXPERIMENTAL APPROACH Filtration and scintillation proximity assays measured equilibrium binding as well as binding kinetics of [35S]GTPγS and [3H]GDP to a mixture of G-proteins as well as individual classes of G-proteins upon binding of structurally different agonists to the M2 muscarinic acetylcholine receptor. KEY RESULTS Agonists displayed biphasic competition curves with the antagonist [3H]-N-methylscopolamine. GTPγS (1 µM) changed the competition curves to monophasic with low affinity and 50 µM GDP produced a similar effect. Depletion of membrane-bound GDP increased the proportion of agonist high-affinity sites. Carbachol accelerated the dissociation of [3H]GDP from membranes. The inverse agonist N-methylscopolamine slowed GDP dissociation and GTPγS binding without changing affinity for GDP. Carbachol affected both GDP association with and dissociation from Gi/o G-proteins but only its dissociation from Gs/olf G-proteins. CONCLUSIONS AND IMPLICATIONS These findings suggest the existence of a low-affinity agonist-receptor conformation complexed with GDP-liganded G-protein. Also the negative cooperativity between GDP and agonist binding at the receptor/G-protein complex determines agonist efficacy. GDP binding reveals differences in action of agonists versus inverse agonists as well as differences in activation of Gi/o versus Gs/olf G-proteins that are not identified by conventional GTPγS binding. PMID:20958290

Negative cooperativity in binding of muscarinic receptor agonists and GDP as a measure of agonist efficacy.

PubMed

Jakubík, J; Janíčková, H; El-Fakahany, E E; Doležal, V

2011-03-01

Conventional determination of agonist efficacy at G-protein coupled receptors is measured by stimulation of guanosine-5'-γ-thiotriphosphate (GTPγS) binding. We analysed the role of guanosine diphosphate (GDP) in the process of activation of the M₂ muscarinic acetylcholine receptor and provide evidence that negative cooperativity between agonist and GDP binding is an alternative measure of agonist efficacy. Filtration and scintillation proximity assays measured equilibrium binding as well as binding kinetics of [³⁵S]GTPγS and [³H]GDP to a mixture of G-proteins as well as individual classes of G-proteins upon binding of structurally different agonists to the M₂ muscarinic acetylcholine receptor. Agonists displayed biphasic competition curves with the antagonist [³H]-N-methylscopolamine. GTPγS (1 µM) changed the competition curves to monophasic with low affinity and 50 µM GDP produced a similar effect. Depletion of membrane-bound GDP increased the proportion of agonist high-affinity sites. Carbachol accelerated the dissociation of [³H]GDP from membranes. The inverse agonist N-methylscopolamine slowed GDP dissociation and GTPγS binding without changing affinity for GDP. Carbachol affected both GDP association with and dissociation from G(i/o) G-proteins but only its dissociation from G(s/olf) G-proteins. These findings suggest the existence of a low-affinity agonist-receptor conformation complexed with GDP-liganded G-protein. Also the negative cooperativity between GDP and agonist binding at the receptor/G-protein complex determines agonist efficacy. GDP binding reveals differences in action of agonists versus inverse agonists as well as differences in activation of G(i/o) versus G(s/olf) G-proteins that are not identified by conventional GTPγS binding. © 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.

Far-field self-focusing and -defocusing radiation behaviors of the electroluminescent light sources due to negative refraction.

PubMed

Yin, Yu-Feng; Lin, Yen-Chen; Tsai, Tsung-Han; Shen, Yi-Chun; Huang, Jianjang

2013-01-15

In recent years, researchers have demonstrated negative refraction theoretically and experimentally by pumping optical power into photonic crystal (PhC) or waveguide structures. The concept of negative refraction can be used to create a perfect lens that focuses an object smaller than the wavelength. By inserting two-dimensional PhCs into the peripheral of a semiconductor light emitting structure, this study presents an electroluminescent device with negative refraction in the visible wavelength range. This approach produces polarization dependent collimation behavior in far-field radiation patterns. The modal dispersion of negative refraction results in strong group velocity modulation, and self-focusing and -defocusing behaviors are apparent from light extraction. This study further verifies experimental results by using theoretic calculations based on equifrequency contours.

Emergence of dynamic cooperativity in the stochastic kinetics of fluctuating enzymes

NASA Astrophysics Data System (ADS)

Kumar, Ashutosh; Chatterjee, Sambarta; Nandi, Mintu; Dua, Arti

2016-08-01

Dynamic co-operativity in monomeric enzymes is characterized in terms of a non-Michaelis-Menten kinetic behaviour. The latter is believed to be associated with mechanisms that include multiple reaction pathways due to enzymatic conformational fluctuations. Recent advances in single-molecule fluorescence spectroscopy have provided new fundamental insights on the possible mechanisms underlying reactions catalyzed by fluctuating enzymes. Here, we present a bottom-up approach to understand enzyme turnover kinetics at physiologically relevant mesoscopic concentrations informed by mechanisms extracted from single-molecule stochastic trajectories. The stochastic approach, presented here, shows the emergence of dynamic co-operativity in terms of a slowing down of the Michaelis-Menten (MM) kinetics resulting in negative co-operativity. For fewer enzymes, dynamic co-operativity emerges due to the combined effects of enzymatic conformational fluctuations and molecular discreteness. The increase in the number of enzymes, however, suppresses the effect of enzymatic conformational fluctuations such that dynamic co-operativity emerges solely due to the discrete changes in the number of reacting species. These results confirm that the turnover kinetics of fluctuating enzyme based on the parallel-pathway MM mechanism switches over to the single-pathway MM mechanism with the increase in the number of enzymes. For large enzyme numbers, convergence to the exact MM equation occurs in the limit of very high substrate concentration as the stochastic kinetics approaches the deterministic behaviour.

Personality and depression: evidence of a possible mediating role for anger trait in the relationship between cooperativeness and depression.

PubMed

Balsamo, Michela

2013-01-01

An increasingly growing area of empirical research has found consistent links between anger, depression, and temperament and character domains of personality, separately. However, precise nature of these relationships remains still unclear, and little is known about its underlying processes. The aim of our explorative research was to conduct a more detailed investigation into the relationships among depression, anger trait, and personality characteristics based on Cloninger's 7-factor personality theory in healthy individuals. In this preliminary study, 230 Italian undergraduates were investigated by using the Temperament and Character Inventory-Revised, the State-Trait Anger Expression Inventory-2, and the Beck Depression Inventory-II. Depression and cooperativeness were expected to have a negative and significant relationship and separate relationships with the trait-anger. Theoretically, a new hypothesis was that the trait-anger would mediate the relationship between depression and cooperativeness. Zero-order and partial correlations and a path analysis based on Baron and Kenny's method (J Pers Soc Psychol.1986;51:1173-1182) for calculating multiple regression analyses were calculated. Consistent with the hypotheses, cooperativeness and depression were strongly associated; the trait-anger was significantly associated with both cooperativeness and depression, and the mediation model fit the data. Behaviors related to the trait-anger could help to explain how depression and reduced cooperativeness are related each other. Copyright © 2013 Elsevier Inc. All rights reserved.

Emergence of dynamic cooperativity in the stochastic kinetics of fluctuating enzymes.

PubMed

Kumar, Ashutosh; Chatterjee, Sambarta; Nandi, Mintu; Dua, Arti

2016-08-28

Dynamic co-operativity in monomeric enzymes is characterized in terms of a non-Michaelis-Menten kinetic behaviour. The latter is believed to be associated with mechanisms that include multiple reaction pathways due to enzymatic conformational fluctuations. Recent advances in single-molecule fluorescence spectroscopy have provided new fundamental insights on the possible mechanisms underlying reactions catalyzed by fluctuating enzymes. Here, we present a bottom-up approach to understand enzyme turnover kinetics at physiologically relevant mesoscopic concentrations informed by mechanisms extracted from single-molecule stochastic trajectories. The stochastic approach, presented here, shows the emergence of dynamic co-operativity in terms of a slowing down of the Michaelis-Menten (MM) kinetics resulting in negative co-operativity. For fewer enzymes, dynamic co-operativity emerges due to the combined effects of enzymatic conformational fluctuations and molecular discreteness. The increase in the number of enzymes, however, suppresses the effect of enzymatic conformational fluctuations such that dynamic co-operativity emerges solely due to the discrete changes in the number of reacting species. These results confirm that the turnover kinetics of fluctuating enzyme based on the parallel-pathway MM mechanism switches over to the single-pathway MM mechanism with the increase in the number of enzymes. For large enzyme numbers, convergence to the exact MM equation occurs in the limit of very high substrate concentration as the stochastic kinetics approaches the deterministic behaviour.

Emergence of dynamic cooperativity in the stochastic kinetics of fluctuating enzymes

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

Kumar, Ashutosh; Chatterjee, Sambarta; Nandi, Mintu

Dynamic co-operativity in monomeric enzymes is characterized in terms of a non-Michaelis-Menten kinetic behaviour. The latter is believed to be associated with mechanisms that include multiple reaction pathways due to enzymatic conformational fluctuations. Recent advances in single-molecule fluorescence spectroscopy have provided new fundamental insights on the possible mechanisms underlying reactions catalyzed by fluctuating enzymes. Here, we present a bottom-up approach to understand enzyme turnover kinetics at physiologically relevant mesoscopic concentrations informed by mechanisms extracted from single-molecule stochastic trajectories. The stochastic approach, presented here, shows the emergence of dynamic co-operativity in terms of a slowing down of the Michaelis-Menten (MM) kineticsmore » resulting in negative co-operativity. For fewer enzymes, dynamic co-operativity emerges due to the combined effects of enzymatic conformational fluctuations and molecular discreteness. The increase in the number of enzymes, however, suppresses the effect of enzymatic conformational fluctuations such that dynamic co-operativity emerges solely due to the discrete changes in the number of reacting species. These results confirm that the turnover kinetics of fluctuating enzyme based on the parallel-pathway MM mechanism switches over to the single-pathway MM mechanism with the increase in the number of enzymes. For large enzyme numbers, convergence to the exact MM equation occurs in the limit of very high substrate concentration as the stochastic kinetics approaches the deterministic behaviour.« less

Learning to Cooperate: The Evolution of Social Rewards in Repeated Interactions.

PubMed

Dridi, Slimane; Akçay, Erol

2018-01-01

Understanding the behavioral and psychological mechanisms underlying social behaviors is one of the major goals of social evolutionary theory. In particular, a persistent question about animal cooperation is to what extent it is supported by other-regarding preferences-the motivation to increase the welfare of others. In many situations, animals adjust their behaviors through learning by responding to the rewards they experience as a consequence of their actions. Therefore, we may ask whether learning in social situations can be driven by evolved other-regarding rewards. Here we develop a mathematical model in order to ask whether the mere act of cooperating with a social partner will evolve to be inherently rewarding. Individuals interact repeatedly in pairs and adjust their behaviors through reinforcement learning. We assume that individuals associate with each game outcome an internal reward value. These perceived rewards are genetically evolving traits. We find that conditionally cooperative rewards that value mutual cooperation positively but the sucker's outcome negatively tend to be evolutionarily stable. Purely other-regarding rewards can evolve only under special parameter combinations. On the other hand, selfish rewards that always lead to pure defection are also evolutionarily successful. These findings are consistent with empirical observations showing that humans tend to display conditionally cooperative behavior and also exhibit a diversity of preferences. Our model also demonstrates the need to further integrate multiple levels of biological causation of behavior.

An effective diagnostic strategy for accurate detection of RhD variants including Asian DEL type in apparently RhD-negative blood donors in Korea.

PubMed

Seo, M H; Won, E J; Hong, Y J; Chun, S; Kwon, J R; Choi, Y S; Kim, J N; Lee, S A; Lim, A H; Kim, S H; Park, K U; Cho, D

2016-11-01

The purpose of this study was to provide an effective RHD genotyping strategy for the East Asian blood donors. RhD phenotyping, weak D testing and RhCE phenotyping were performed on 110 samples from members of the RhD-negative club, private organization composed of RhD-negative blood donors, in the GwangJu-Chonnam region of Korea. The RHD promoter, intron 4, and exons 7 and 10 were analysed by real-time PCR. Two nucleotide changes (c.1227 G>A, and c.1222 T>C) in exon 9 were analysed by sequencing. Of 110 RhD-negative club members, 79 (71·8%) showed complete deletion of the RHD gene, 10 (9·1%) showed results consistent with RHD-CE-D hybrid, and 21 (19·1%) showed amplification of RHD promoter, intron 4, and exons 7 and 10. Of the latter group, 16 (14·5%) were in the DEL blood group including c.1227 G>A (N = 14) and c.1222 T>C (N = 2), 2 (1·8%) were weak D, 1(0·9%) was partial D, and 2 (1·8%) were undetermined. The RhD-negative phenotype samples consisted of 58 C-E-c+e+, 19 C-E+c+e+, 3 C-E+c+e-, 21 C+E-c+e-, 6 C+E-c+e+ and 3 C+E-c-e + . Notably, all 58 samples with the C-E-c+e+ phenotype were revealed to have complete deletion of the RHD gene. The C-E-c+e+ phenotype showed 100% positive predictive value for detecting D-negative cases. RHD genotyping is not required in half of D-negative cases. We suggest here an effective RHD genotyping strategy for accurate detection of RhD variants in apparently RhD-negative blood donors in East Asia. © 2016 International Society of Blood Transfusion.

Unraveling the B. pseudomallei Heptokinase WcbL: From Structure to Drug Discovery

PubMed Central

Vivoli, Mirella; Isupov, Michail N.; Nicholas, Rebecca; Hill, Andrew; Scott, Andrew E.; Kosma, Paul; Prior, Joann L.; Harmer, Nicholas J.

2015-01-01

Summary Gram-negative bacteria utilize heptoses as part of their repertoire of extracellular polysaccharide virulence determinants. Disruption of heptose biosynthesis offers an attractive target for novel antimicrobials. A critical step in the synthesis of heptoses is their 1-O phosphorylation, mediated by kinases such as HldE or WcbL. Here, we present the structure of WcbL from Burkholderia pseudomallei. We report that WcbL operates through a sequential ordered Bi-Bi mechanism, loading the heptose first and then ATP. We show that dimeric WcbL binds ATP anti-cooperatively in the absence of heptose, and cooperatively in its presence. Modeling of WcbL suggests that heptose binding causes an elegant switch in the hydrogen-bonding network, facilitating the binding of a second ATP molecule. Finally, we screened a library of drug-like fragments, identifying hits that potently inhibit WcbL. Our results provide a novel mechanism for control of substrate binding and emphasize WcbL as an attractive anti-microbial target for Gram-negative bacteria. PMID:26687481

The US-Nigerian Military Cooperation: US Africom As A Mentor For Nigeria’s Military Efforts At Promoting Respect For Human Rights

DTIC Science & Technology

2016-06-01

continue to publish reports of human rights violation against Nigeria military. This is worrying, because it does not only effect civil-military relations...in Nigeria , but also negatively impact its relations with the United States (US) and other allies. The need for external support for Nigeria ...stability operations. In the case of Nigeria , reports of human rights abuses against its military have negatively impacted its relations with the

Evaluation of dried vegetables residues for poultry: II. Effects of feeding cabbage leaf residues on broiler performance, ileal digestibility and total tract nutrient digestibility.

PubMed

Mustafa, A F; Baurhoo, B

2017-03-01

A study was conducted to investigate the effects of partial replacing corn and soybean meal with dried cabbage leaf residues (DCR) on broiler growth performance, apparent ileal nutrient digestibility, and apparent total tract nutrient utilization. Dietary treatments include 4 levels of DCR (0, 3, 6, and 9%). Two hundred and twenty-four day-old male broilers were randomly assigned to one of 4 groups (8 cage replicates; 7 birds/cage) and grown over a 35-d experimental period. Results showed that feeding DCR had no effects on daily body weigh gain (average 53.4 g/d), daily feed intake (average 94.9 g/d), and feed conversion ratio (average 1.78 g of feed/g of gain). Inclusion of DCR reduced apparent ileal DM (quadratic effect, P < 0.001), OM (linear effect, P = 0.012), and CP (quadratic effect, P = 0.001) digestibility of younger birds (d 21) while incremental levels of DCR had no effect on apparent ileal nutrient digestibilities of older birds (d 35). Apparent total tract digestibility of DM, OM, and CP increased (linear effect, P < 0.001) as the level of DCR increased. It was concluded that the inclusion of DCR in broiler diets up to 9% had no negative impact on bird performance and apparent ileal digestibility of older birds and improved apparent total tract nutrient digestibility. © 2016 Poultry Science Association Inc.

Rational design of viscosity reducing mutants of a monoclonal antibody: Hydrophobic versus electrostatic inter-molecular interactions

PubMed Central

Nichols, Pilarin; Li, Li; Kumar, Sandeep; Buck, Patrick M; Singh, Satish K; Goswami, Sumit; Balthazor, Bryan; Conley, Tami R; Sek, David; Allen, Martin J

2015-01-01

High viscosity of monoclonal antibody formulations at concentrations ≥100 mg/mL can impede their development as products suitable for subcutaneous delivery. The effects of hydrophobic and electrostatic intermolecular interactions on the solution behavior of MAB 1, which becomes unacceptably viscous at high concentrations, was studied by testing 5 single point mutants. The mutations were designed to reduce viscosity by disrupting either an aggregation prone region (APR), which also participates in 2 hydrophobic surface patches, or a negatively charged surface patch in the variable region. The disruption of an APR that lies at the interface of light and heavy chain variable domains, VH and VL, via L45K mutation destabilized MAB 1 and abolished antigen binding. However, mutation at the preceding residue (V44K), which also lies in the same APR, increased apparent solubility and reduced viscosity of MAB 1 without sacrificing antigen binding or thermal stability. Neutralizing the negatively charged surface patch (E59Y) also increased apparent solubility and reduced viscosity of MAB 1, but charge reversal at the same position (E59K/R) caused destabilization, decreased solubility and led to difficulties in sample manipulation that precluded their viscosity measurements at high concentrations. Both V44K and E59Y mutations showed similar increase in apparent solubility. However, the viscosity profile of E59Y was considerably better than that of the V44K, providing evidence that inter-molecular interactions in MAB 1 are electrostatically driven. In conclusion, neutralizing negatively charged surface patches may be more beneficial toward reducing viscosity of highly concentrated antibody solutions than charge reversal or aggregation prone motif disruption. PMID:25559441

Increased brain-predicted aging in treated HIV disease

PubMed Central

Underwood, Jonathan; Caan, Matthan W.A.; De Francesco, Davide; van Zoest, Rosan A.; Leech, Robert; Wit, Ferdinand W.N.M.; Portegies, Peter; Geurtsen, Gert J.; Schmand, Ben A.; Schim van der Loeff, Maarten F.; Franceschi, Claudio; Sabin, Caroline A.; Majoie, Charles B.L.M.; Winston, Alan; Reiss, Peter; Sharp, David J.

2017-01-01

Objective: To establish whether HIV disease is associated with abnormal levels of age-related brain atrophy, by estimating apparent brain age using neuroimaging and exploring whether these estimates related to HIV status, age, cognitive performance, and HIV-related clinical parameters. Methods: A large sample of virologically suppressed HIV-positive adults (n = 162, age 45–82 years) and highly comparable HIV-negative controls (n = 105) were recruited as part of the Comorbidity in Relation to AIDS (COBRA) collaboration. Using T1-weighted MRI scans, a machine-learning model of healthy brain aging was defined in an independent cohort (n = 2,001, aged 18–90 years). Neuroimaging data from HIV-positive and HIV-negative individuals were then used to estimate brain-predicted age; then brain-predicted age difference (brain-PAD = brain-predicted brain age − chronological age) scores were calculated. Neuropsychological and clinical assessments were also carried out. Results: HIV-positive individuals had greater brain-PAD score (mean ± SD 2.15 ± 7.79 years) compared to HIV-negative individuals (−0.87 ± 8.40 years; b = 3.48, p < 0.01). Increased brain-PAD score was associated with decreased performance in multiple cognitive domains (information processing speed, executive function, memory) and general cognitive performance across all participants. Brain-PAD score was not associated with age, duration of HIV infection, or other HIV-related measures. Conclusion: Increased apparent brain aging, predicted using neuroimaging, was observed in HIV-positive adults, despite effective viral suppression. Furthermore, the magnitude of increased apparent brain aging related to cognitive deficits. However, predicted brain age difference did not correlate with chronological age or duration of HIV infection, suggesting that HIV disease may accentuate rather than accelerate brain aging. PMID:28258081

Rational design of viscosity reducing mutants of a monoclonal antibody: hydrophobic versus electrostatic inter-molecular interactions.

PubMed

Nichols, Pilarin; Li, Li; Kumar, Sandeep; Buck, Patrick M; Singh, Satish K; Goswami, Sumit; Balthazor, Bryan; Conley, Tami R; Sek, David; Allen, Martin J

2015-01-01

High viscosity of monoclonal antibody formulations at concentrations ≥100 mg/mL can impede their development as products suitable for subcutaneous delivery. The effects of hydrophobic and electrostatic intermolecular interactions on the solution behavior of MAB 1, which becomes unacceptably viscous at high concentrations, was studied by testing 5 single point mutants. The mutations were designed to reduce viscosity by disrupting either an aggregation prone region (APR), which also participates in 2 hydrophobic surface patches, or a negatively charged surface patch in the variable region. The disruption of an APR that lies at the interface of light and heavy chain variable domains, VH and VL, via L45K mutation destabilized MAB 1 and abolished antigen binding. However, mutation at the preceding residue (V44K), which also lies in the same APR, increased apparent solubility and reduced viscosity of MAB 1 without sacrificing antigen binding or thermal stability. Neutralizing the negatively charged surface patch (E59Y) also increased apparent solubility and reduced viscosity of MAB 1, but charge reversal at the same position (E59K/R) caused destabilization, decreased solubility and led to difficulties in sample manipulation that precluded their viscosity measurements at high concentrations. Both V44K and E59Y mutations showed similar increase in apparent solubility. However, the viscosity profile of E59Y was considerably better than that of the V44K, providing evidence that inter-molecular interactions in MAB 1 are electrostatically driven. In conclusion, neutralizing negatively charged surface patches may be more beneficial toward reducing viscosity of highly concentrated antibody solutions than charge reversal or aggregation prone motif disruption.

Increased brain-predicted aging in treated HIV disease.

PubMed

Cole, James H; Underwood, Jonathan; Caan, Matthan W A; De Francesco, Davide; van Zoest, Rosan A; Leech, Robert; Wit, Ferdinand W N M; Portegies, Peter; Geurtsen, Gert J; Schmand, Ben A; Schim van der Loeff, Maarten F; Franceschi, Claudio; Sabin, Caroline A; Majoie, Charles B L M; Winston, Alan; Reiss, Peter; Sharp, David J

2017-04-04

To establish whether HIV disease is associated with abnormal levels of age-related brain atrophy, by estimating apparent brain age using neuroimaging and exploring whether these estimates related to HIV status, age, cognitive performance, and HIV-related clinical parameters. A large sample of virologically suppressed HIV-positive adults (n = 162, age 45-82 years) and highly comparable HIV-negative controls (n = 105) were recruited as part of the Comorbidity in Relation to AIDS (COBRA) collaboration. Using T1-weighted MRI scans, a machine-learning model of healthy brain aging was defined in an independent cohort (n = 2,001, aged 18-90 years). Neuroimaging data from HIV-positive and HIV-negative individuals were then used to estimate brain-predicted age; then brain-predicted age difference (brain-PAD = brain-predicted brain age - chronological age) scores were calculated. Neuropsychological and clinical assessments were also carried out. HIV-positive individuals had greater brain-PAD score (mean ± SD 2.15 ± 7.79 years) compared to HIV-negative individuals (-0.87 ± 8.40 years; b = 3.48, p < 0.01). Increased brain-PAD score was associated with decreased performance in multiple cognitive domains (information processing speed, executive function, memory) and general cognitive performance across all participants. Brain-PAD score was not associated with age, duration of HIV infection, or other HIV-related measures. Increased apparent brain aging, predicted using neuroimaging, was observed in HIV-positive adults, despite effective viral suppression. Furthermore, the magnitude of increased apparent brain aging related to cognitive deficits. However, predicted brain age difference did not correlate with chronological age or duration of HIV infection, suggesting that HIV disease may accentuate rather than accelerate brain aging. Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

Pharmacists in primary care. Determinants of the care-providing function of Dutch community pharmacists in primary care.

PubMed

Muijrers, Paul E M; Knottnerus, J André; Sijbrandij, Jildou; Janknegt, Rob; Grol, Richard P T M

2004-10-01

To identify determinants of the care-providing function of the community pharmacists (CPs) to explain variations in professional practice. The Netherlands 2001. 328 CPs. A cross-sectional questionnaire survey was performed. Questionnaires were used to collect data about the care provided in pharmacies. As dependent variables three partial constructs: 'individual patient care', 'registration of the care', and 'cooperation with GPs', and one total construct: 'care function' were formed. Independent variables were: gender, work experience, attitude to the care-providing function, tenure, relationship with GPs, pharmacist trainer, frequency of postgraduate training, workload, part-time working, frequency of contact with pharmaceutical representatives, presence of technicians with a specialised caring duty, size of the pharmacy, urbanisation, competition, franchise pharmacy, presence of sufficient personnel. A multiple-regression analysis was performed. Respondents 71%; of the respondents 29% never enquired about the patient's experience when supplying a medication for the second time. The supply of self-care remedies was never registered by 11% of respondents. Ninety percent of pharmacists participate more than four times per year in Pharmacotherapy Audit Meetings. The attitude of the pharmacist, relationship with the GP, presence of specialised technicians, frequency of postgraduate training and the type of tenure are significantly positively correlated with a care-providing function. Being a pharmacist trainer is significantly positively related with 'individual patient care', the frequency of postgraduate training is significantly positively correlated with 'registration of the care' and the number of years in service is significantly negatively correlated with 'cooperation with GPs'. There is a negative correlation between the cooperation with GPs and the number of years a pharmacist has been in service. Based on this survey, the development of programmes focused on optimal attitude, and cooperation between pharmacists and GPs is recommended.

cSrc and Her2 Signaling Pathways Cooperate with Estrogen to Promote ER Phosphorylation, Ubiquitination and Proteolysis in ER Negative Breast Cancers

DTIC Science & Technology

2007-03-01

68 HR positive tumors were compared with 23 ’triple receptor-negative’ tumors (negative for ER and PR by IHC and for HER2 by FISH ), Src levels were...47. Rosen,N., Bolen,J.B., Schwartz,A.M., Cohen,P., DeSeau,V., and Israel ,M.A. 1986. Analysis of pp60c-src protein kinase activity in human tumor...www.aacrjournals.org cancers has been associated with poor prognosis (41, 42). Cyclin D1 deficient mice are resistant to breast cancers induced by transgenic ErbB2/neu

The Americanization of the Croatian language.

PubMed

Bosnar-Valković, Brigita; Blazević, Nevenka; Gjuran-Coha, Anamarija

2008-12-01

The USA is spreading their political, military, economic, scientific, artistic and cultural mission throughout the world. The aim of this paper is to bring to the attention the Americanization of the Croatian language particularly evident in the newly adopted language manners, in teenage language, in specialist languages, in the field of advertising and in political correctness. The spread of Americanization of the Croatian language has both negative and positive effects. Positive effects can be regarded as enrichment of the Croatian language, whereas the negative ones endanger its deep structure. Positive effects should be supported and negative minimized through the cooperation between experts in linguistics and politics.

Gossip as an alternative for direct observation in games of indirect reciprocity.

PubMed

Sommerfeld, Ralf D; Krambeck, Hans-Jürgen; Semmann, Dirk; Milinski, Manfred

2007-10-30

Communication about social topics is abundant in human societies, and many functions have been attributed to such gossiping. One of these proposed functions is the management of reputations. Reputation by itself has been shown to have a strong influence on cooperation dynamics in games of indirect reciprocity, and this notion helps to explain the observed high level of cooperation in humans. Here we designed a game to test a widespread assumption that gossip functions as a vector for the transmission of social information. This empirical study (with 14 groups of nine students each) focuses on the composition of gossip, information transfer by gossip, and the behavior based on gossip information. We show that gossip has a strong influence on the resulting behavior even when participants have access to the original information (i.e., direct observation) as well as gossip about the same information. Thus, it is evident that gossip has a strong manipulative potential. Furthermore, gossip about cooperative individuals is more positive than gossip about uncooperative individuals, gossip comments transmit social information successfully, and cooperation levels are higher when people encounter positive compared with negative gossip.

Active site specificity profiling of the matrix metalloproteinase family: Proteomic identification of 4300 cleavage sites by nine MMPs explored with structural and synthetic peptide cleavage analyses.

PubMed

Eckhard, Ulrich; Huesgen, Pitter F; Schilling, Oliver; Bellac, Caroline L; Butler, Georgina S; Cox, Jennifer H; Dufour, Antoine; Goebeler, Verena; Kappelhoff, Reinhild; Keller, Ulrich Auf dem; Klein, Theo; Lange, Philipp F; Marino, Giada; Morrison, Charlotte J; Prudova, Anna; Rodriguez, David; Starr, Amanda E; Wang, Yili; Overall, Christopher M

2016-01-01

Secreted and membrane tethered matrix metalloproteinases (MMPs) are key homeostatic proteases regulating the extracellular signaling and structural matrix environment of cells and tissues. For drug targeting of proteases, selectivity for individual molecules is highly desired and can be met by high yield active site specificity profiling. Using the high throughput Proteomic Identification of protease Cleavage Sites (PICS) method to simultaneously profile both the prime and non-prime sides of the cleavage sites of nine human MMPs, we identified more than 4300 cleavages from P6 to P6' in biologically diverse human peptide libraries. MMP specificity and kinetic efficiency were mainly guided by aliphatic and aromatic residues in P1' (with a ~32-93% preference for leucine depending on the MMP), and basic and small residues in P2' and P3', respectively. A wide differential preference for the hallmark P3 proline was found between MMPs ranging from 15 to 46%, yet when combined in the same peptide with the universally preferred P1' leucine, an unexpected negative cooperativity emerged. This was not observed in previous studies, probably due to the paucity of approaches that profile both the prime and non-prime sides together, and the masking of subsite cooperativity effects by global heat maps and iceLogos. These caveats make it critical to check for these biologically highly important effects by fixing all 20 amino acids one-by-one in the respective subsites and thorough assessing of the inferred specificity logo changes. Indeed an analysis of bona fide MEROPS physiological substrate cleavage data revealed that of the 37 natural substrates with either a P3-Pro or a P1'-Leu only 5 shared both features, confirming the PICS data. Upon probing with several new quenched-fluorescent peptides, rationally designed on our specificity data, the negative cooperativity was explained by reduced non-prime side flexibility constraining accommodation of the rigidifying P3 proline with leucine locked in S1'. Similar negative cooperativity between P3 proline and the novel preference for asparagine in P1 cements our conclusion that non-prime side flexibility greatly impacts MMP binding affinity and cleavage efficiency. Thus, unexpected sequence cooperativity consequences were revealed by PICS that uniquely encompasses both the non-prime and prime sides flanking the proteomic-pinpointed scissile bond. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Higher Social Intelligence Can Impair Source Memory

ERIC Educational Resources Information Center

Barber, Sarah J.; Franklin, Nancy; Naka, Makiko; Yoshimura, Hiroki

2010-01-01

Source monitoring is made difficult when the similarity between candidate sources increases. The current work examines how individual differences in social intelligence and perspective-taking abilities serve to increase source similarity and thus negatively impact source memory. Strangers first engaged in a cooperative storytelling task. On each…

Learning without Borders

ERIC Educational Resources Information Center

Adelman, Clifford

2008-01-01

Each time the Organization for Economic Cooperation and Development announces that America's students are falling behind those of other countries, and with every business section article on America's trade deficit with China, America sees a new commission to reinforce the negatives and urge dramatic upgrading of the workforce. This author states…

Reciprocity and the Tragedies of Maintaining and Providing the Commons

PubMed Central

Gächter, Simon; Kölle, Felix; Quercia, Simone

2017-01-01

Social cooperation often requires collectively beneficial but individually costly restraint to maintain a public good1–4, or it needs costly generosity to create one1,5. Status quo effects6 predict that maintaining a public good is easier than providing a new one. Here we show experimentally and with simulations that even under identical incentives, low levels of cooperation (the ‘tragedy of the commons’2) are systematically more likely in Maintenance than Provision. Across three series of experiments, we find that strong and weak positive reciprocity, known to be fundamental tendencies underpinning human cooperation7–10, are substantially diminished under Maintenance compared to Provision. As we show in a fourth experiment, the opposite holds for negative reciprocity (‘punishment’). Our findings suggest that incentives to avoid the ‘tragedy of the commons’ need to contend with dilemma-specific reciprocity. PMID:28944297

Evolution of responses to (un)fairness.

PubMed

Brosnan, Sarah F; de Waal, Frans B M

2014-10-17

The human sense of fairness is an evolutionary puzzle. To study this, we can look to other species, in which this can be translated empirically into responses to reward distribution. Passive and active protest against receiving less than a partner for the same task is widespread in species that cooperate outside kinship and mating bonds. There is less evidence that nonhuman species seek to equalize outcomes to their own detriment, yet the latter has been documented in our closest relatives, the apes. This reaction probably reflects an attempt to forestall partner dissatisfaction with obtained outcomes and its negative impact on future cooperation. We hypothesize that it is the evolution of this response that allowed the development of a complete sense of fairness in humans, which aims not at equality for its own sake but for the sake of continued cooperation. Copyright © 2014, American Association for the Advancement of Science.

Psychophysiological correlates of interpersonal cooperation and aggression.

PubMed

Wang, Yiwen; Roberts, Kathryn; Yuan, Bo; Zhang, Wenxin; Shen, Deli; Simons, Robert

2013-07-01

Mimicking real world situations, the Chicken Game allows scientists to examine human decision-making when the outcome is not entirely within one person's control. In this social dilemma task, two players independently choose either to safely cooperate with, or riskily aggress against, the other player, and the unique combination of their choices specifies the outcome for each. Coupling the Chicken Game with psychophysiological measures, we confirmed our two hypotheses: that an individual perceives an outcome as most negative when she chooses to cooperate and the other player violates that trust and aggresses, and that motivational salience of an outcome is greater when an individual chooses to aggress and when she gains money. Collectively, the data demonstrate the utility of pairing true social dilemma tasks like the Chicken Game with psychophysiological measures to better understand decision-making. Copyright © 2013 Elsevier B.V. All rights reserved.

Exit, Punishment and Rewards in Commons Dilemmas: An Experimental Study

PubMed Central

Bravo, Giangiacomo; Squazzoni, Flaminio

2013-01-01

Commons dilemmas are interaction situations where a common good is provided or exploited by a group of individuals so that optimal collective outcomes clash with private interests. Although in these situations, social norms and institutions exist that might help individuals to cooperate, little is known about the interaction effects between positive and negative incentives and exit options by individuals. We performed a modified public good game experiment to examine the effect of exit, rewards and punishment, as well as the interplay between exit and rewards and punishment. We found that punishment had a stronger effect than rewards on cooperation if considered by itself, whereas rewards had a stronger effect when combined with voluntary participation. This can be explained in terms of the ‘framing effect’, i.e., as the combination of exit and rewards might induce people to attach higher expected payoffs to cooperative strategies and expect better behaviour from others. PMID:23936356

A dynamically coupled allosteric network underlies binding cooperativity in Src kinase

PubMed Central

Foda, Zachariah H.; Shan, Yibing; Kim, Eric T.; Shaw, David E.; Seeliger, Markus A.

2015-01-01

Protein tyrosine kinases are attractive drug targets because many human diseases are associated with the deregulation of kinase activity. However, how the catalytic kinase domain integrates different signals and switches from an active to an inactive conformation remains incompletely understood. Here we identify an allosteric network of dynamically coupled amino acids in Src kinase that connects regulatory sites to the ATP- and substrate-binding sites. Surprisingly, reactants (ATP and peptide substrates) bind with negative cooperativity to Src kinase while products (ADP and phosphopeptide) bind with positive cooperativity. We confirm the molecular details of the signal relay through the allosteric network by biochemical studies. Experiments on two additional protein tyrosine kinases indicate that the allosteric network may be largely conserved among these enzymes. Our work provides new insights into the regulation of protein tyrosine kinases and establishes a potential conduit by which resistance mutations to ATP-competitive kinase inhibitors can affect their activity. PMID:25600932

Exit, punishment and rewards in commons dilemmas: an experimental study.

PubMed

Bravo, Giangiacomo; Squazzoni, Flaminio

2013-01-01

Commons dilemmas are interaction situations where a common good is provided or exploited by a group of individuals so that optimal collective outcomes clash with private interests. Although in these situations, social norms and institutions exist that might help individuals to cooperate, little is known about the interaction effects between positive and negative incentives and exit options by individuals. We performed a modified public good game experiment to examine the effect of exit, rewards and punishment, as well as the interplay between exit and rewards and punishment. We found that punishment had a stronger effect than rewards on cooperation if considered by itself, whereas rewards had a stronger effect when combined with voluntary participation. This can be explained in terms of the 'framing effect', i.e., as the combination of exit and rewards might induce people to attach higher expected payoffs to cooperative strategies and expect better behaviour from others.

The oxidative costs of reproduction are group-size dependent in a wild cooperative breeder.

PubMed

Cram, Dominic L; Blount, Jonathan D; Young, Andrew J

2015-11-22

Life-history theory assumes that reproduction entails a cost, and research on cooperatively breeding societies suggests that the cooperative sharing of workloads can reduce this cost. However, the physiological mechanisms that underpin both the costs of reproduction and the benefits of cooperation remain poorly understood. It has been hypothesized that reproductive costs may arise in part from oxidative stress, as reproductive investment may elevate exposure to reactive oxygen species, compromising survival and future reproduction and accelerating senescence. However, experimental evidence of oxidative costs of reproduction in the wild remains scarce. Here, we use a clutch-removal experiment to investigate the oxidative costs of reproduction in a wild cooperatively breeding bird, the white-browed sparrow weaver, Plocepasser mahali. Our results reveal costs of reproduction that are dependent on group size: relative to individuals in groups whose eggs were experimentally removed, individuals in groups that raised offspring experienced an associated cost (elevated oxidative damage and reduced body mass), but only if they were in small groups containing fewer or no helpers. Furthermore, during nestling provisioning, individuals that provisioned at higher rates showed greater within-individual declines in body mass and antioxidant protection. Our results provide rare experimental evidence that reproduction can negatively impact both oxidative status and body mass in the wild, and suggest that these costs can be mitigated in cooperative societies by the presence of additional helpers. These findings have implications for our understanding of the energetic and oxidative costs of reproduction, and the benefits of cooperation in animal societies. © 2015 The Authors.

Sibling cooperative and externalizing behaviors in families raising children with disabilities.

PubMed

Platt, Christine; Roper, Susanne Olsen; Mandleco, Barbara; Freeborn, Donna

2014-01-01

Raising a child with a disability (CWD) in the home is increasing across the globe. Because of caregiver burden and the complexity of care, there is growing concern for typically developing sibling (TDS) outcomes. The aim of the study was to examine whether caregiver burden, parenting style, and sibling relationships in families raising a CWD are associated with cooperative and externalizing behaviors in TDS. This correlational study included 189 families raising both a CWD and a TDS. Multilevel modeling was used to identify which variables were most predictive of TDS outcomes and if there were parent gender effects. Authoritative parenting was positively associated with cooperative behaviors. Authoritarian parenting was positively associated with externalizing behaviors. Multilevel modeling revealed caregiver burden was a significant predictor of sibling behaviors in the first model. When parenting style was added as a predictor, it was also significant. When sibling relationships were added as predictors, they were significant predictors for both cooperative and externalizing TDS behaviors; however, caregiver burden was no longer significant. Authoritarian parenting significantly predicted externalizing behaviors, and authoritative parenting was significantly related to cooperative behaviors. In families raising a CWD, positive sibling relationships may help negate the effects of caregiver burden and are more predictive of TDS outcomes than some parenting practices.

Parental care masks a density-dependent shift from cooperation to competition among burying beetle larvae.

PubMed

Schrader, Matthew; Jarrett, Benjamin J M; Kilner, Rebecca M

2015-04-01

Studies of siblings have focused mainly on their competitive interactions and to a lesser extent on their cooperation. However, competition and cooperation are at opposite ends on a continuum of possible interactions and the nature of these interactions may be flexible with ecological factors tipping the balance toward competition in some environments and cooperation in others. Here we show that the presence of parental care and the density of larvae on the breeding carcass change the outcome of sibling interactions in burying beetle broods. With full parental care there was a strong negative relationship between larval density and larval mass, consistent with sibling competition for resources. In the absence of care, initial increases in larval density had beneficial effects on larval mass but further increases in larval density reduced larval mass. This likely reflects a density-dependent shift between cooperation and competition. In a second experiment, we manipulated larval density and removed parental care. We found that the ability of larvae to penetrate the breeding carcass increased with larval density and that feeding within the carcass resulted in heavier larvae than feeding outside the carcass. However, larval density did not influence carcass decay. © 2015 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Inequity-aversion and relative kindness intention jointly determine the expenditure of effort in project teams

PubMed Central

Rapoport, Amnon; Zhao, Rui

2017-01-01

The literature on team cooperation has neglected the effects of relative kindness intention on cooperation, which we measure by comparing the kindness intentions of an agent to her group members to the kindness shown by other members to this same agent. We argue that the agent’s emotional reaction to material payoff inequity is not constant, but rather affected by her relative kindness intention. Then, we apply the model to team projects with multiple partners and investigate how inequity-aversion and relative kindness intention jointly influence team cooperation. We first consider the case of homogeneous agents, where their marginal productivity levels and technical capacities are the same, and then consider the case of heterogeneous agents, where their marginal productivity levels and technical capacities are not the same. Our results show that inequity-aversion has no effect on effort expenditure in the former case, but does affect it in the latter case. The consideration of relative kindness intention may impact the agents’ optimal cooperative effort expenditure when their technical capacities are different. In addition, it is beneficial for team cooperation, and might not only reduce the negative impact but also enhance the positive impact of inequity-aversion on the agents’ effort expenditures. PMID:28459853

Role of Electrostatic Interactions on the Transport of Druglike Molecules in Hydrogel-Based Articular Cartilage Mimics: Implications for Drug Delivery.

PubMed

Ye, Fengbin; Baldursdottir, Stefania; Hvidt, Søren; Jensen, Henrik; Larsen, Susan W; Yaghmur, Anan; Larsen, Claus; Østergaard, Jesper

2016-03-07

In the field of drug delivery to the articular cartilage, it is advantageous to apply artificial tissue models as surrogates of cartilage for investigating drug transport and release properties. In this study, artificial cartilage models consisting of 0.5% (w/v) agarose gel containing 0.5% (w/v) chondroitin sulfate or 0.5% (w/v) hyaluronic acid were developed, and their rheological and morphological properties were characterized. UV imaging was utilized to quantify the transport properties of the following four model compounds in the agarose gel and in the developed artificial cartilage models: H-Ala-β-naphthylamide, H-Lys-Lys-β-naphthylamide, lysozyme, and α-lactalbumin. The obtained results showed that the incorporation of the polyelectrolytes chondroitin sulfate or hyaluronic acid into agarose gel induced a significant reduction in the apparent diffusivities of the cationic model compounds as compared to the pure agarose gel. The decrease in apparent diffusivity of the cationic compounds was not caused by a change in the gel structure since a similar reduction in apparent diffusivity was not observed for the net negatively charged protein α-lactalbumin. The apparent diffusivity of the cationic compounds in the negatively charged hydrogels was highly dependent on the ionic strength, pointing out the importance of electrostatic interactions between the diffusant and the polyelectrolytes. Solution based affinity studies between the model compounds and the two investigated polyelectrolytes further confirmed the electrostatic nature of their interactions. The results obtained from the UV imaging diffusion studies are important for understanding the effect of drug physicochemical properties on the transport in articular cartilage. The extracted information may be useful in the development of hydrogels for in vitro release testing having features resembling the articular cartilage.

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

NASA Astrophysics Data System (ADS)

Kuchinsky, Leah R.

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

Biochemical and structural characterization of a novel cooperative binding mode by Pit-1 with CATT repeats in the macrophage migration inhibitory factor promoter

PubMed Central

Agarwal, Sorabh

2018-01-01

Abstract Overexpression of the proinflammatory cytokine macrophage migration inhibitory factor (MIF) is linked to a number of autoimmune diseases and cancer. MIF production has been correlated to the number of CATT repeats in a microsatellite region upstream of the MIF gene. We have characterized the interaction of pituitary-specific positive transcription factor 1 (Pit-1) with a portion of the MIF promoter region flanking a microsatellite polymorphism (−794 CATT5–8). Using fluorescence anisotropy, we quantified tight complex formation between Pit-1 and an oligonucleotide consisting of eight consecutive CATT repeats (8xCATT) with an apparent Kd of 35 nM. Using competition experiments we found a 23 base pair oligonucleotide with 4xCATT repeats to be the minimum DNA sequence necessary for high affinity interaction with Pit-1. The stoichiometry of the Pit-1 DNA interaction was determined to be 2:1 and binding is cooperative in nature. We subsequently structurally characterized the complex and discovered a completely novel binding mode for Pit-1 in contrast to previously described Pit-1 complex structures. The affinity of Pit-1 for the CATT target sequence was found to be highly dependent on cooperativity. This work lays the groundwork for understanding transcriptional regulation of MIF and pursuing Pit-1 as a therapeutic target to treat MIF-mediated inflammatory disorders. PMID:29186613

Membrane Modulates Affinity for Calcium Ion to Create an Apparent Cooperative Binding Response by Annexin a5

PubMed Central

Gauer, Jacob W.; Knutson, Kristofer J.; Jaworski, Samantha R.; Rice, Anne M.; Rannikko, Anika M.; Lentz, Barry R.; Hinderliter, Anne

2013-01-01

Isothermal titration calorimetry was used to characterize the binding of calcium ion (Ca2+) and phospholipid to the peripheral membrane-binding protein annexin a5. The phospholipid was a binary mixture of a neutral and an acidic phospholipid, specifically phosphatidylcholine and phosphatidylserine in the form of large unilamellar vesicles. To stringently define the mode of binding, a global fit of data collected in the presence and absence of membrane concentrations exceeding protein saturation was performed. A partition function defined the contribution of all heat-evolving or heat-absorbing binding states. We find that annexin a5 binds Ca2+ in solution according to a simple independent-site model (solution-state affinity). In the presence of phosphatidylserine-containing liposomes, binding of Ca2+ differentiates into two classes of sites, both of which have higher affinity compared with the solution-state affinity. As in the solution-state scenario, the sites within each class were described with an independent-site model. Transitioning from a solution state with lower Ca2+ affinity to a membrane-associated, higher Ca2+ affinity state, results in cooperative binding. We discuss how weak membrane association of annexin a5 prior to Ca2+ influx is the basis for the cooperative response of annexin a5 toward Ca2+, and the role of membrane organization in this response. PMID:23746516

Individuals in the criminal justice system show differences in cooperative behaviour: Implications from cooperative games.

PubMed

Clark, Brendan C; Thorne, Christopher B; Hendricks, Peter S; Sharp, Carla; Clark, Shane K; Cropsey, Karen L

2015-07-01

The high rate of incarceration in the USA warrants continued exploration into understanding and ameliorating criminal behaviour. The growing use of cooperative games to measure developing prosocial behaviours has never been explored in a US criminal justice population. The aim of this study is to examine cooperative game play among offenders under supervision in the community. We hypothesised that the offenders would use more guarded and self-preserving strategies and be more likely to excel in short-lived interactions than law-abiding community citizens. Community supervised offenders (83) and general population comparison participants (41) were recruited by town centre adverts placed in popular shops. Using the supervision centres as venues, all participants were asked to complete four cooperative games (prisoner's dilemma, public goods game, ultimatum game and trust game), not knowing the identity of the other player who was always, in fact, the experimenter. The offender and general population groups were similar in age (early 30s), sex (2/3 men), race (45% white) and IQ distribution (low average range). Offenders made lower offers in the ultimatum game, had lower scores in the prisoner's dilemma, made lower investments and offered lower returns in the trust game and contributed less in the public goods game. Even community-based offenders thus seem to have deficits in the kinds of gameplay, which are informed by theories of social cooperation, but the direction of relationship with offending remains unclear. The apparent deficits may reflect adaptation to a hostile environment where trust and reciprocity are not rewarded. It is also important to recognise that these community-based offenders did develop play indicative of trust and reciprocity, they just did so more slowly than the comparison group. This may have implications for allowing time for rapport to develop in supervisory relationships. Finally, offenders may benefit from learning that although more guarded behaviours may be adaptive in a rough neighbourhood or in jail, they may be maladaptive and limit their success in other settings such as the work place. Copyright © 2014 John Wiley & Sons, Ltd.

Patch depletion, niche structuring and the evolution of co-operative foraging

PubMed Central

2011-01-01

Background Many animals live in groups. One proposed reason is that grouping allows cooperative food finding. Group foraging models suggest that grouping could increase food finding rates, but that such group processes could be evolutionarily unstable. These models assume discrete food patches which are fully detectable. However, often animals may only be able to perceive local parts of larger-scale environmental patterns. We therefore use a spatial individual-based model where food patches are aggregates of food items beyond the scale of individual perception. We then study the evolution of foraging and grouping behavior in environments with different resource distributions. Results Our results show that grouping can evolve to increase food intake rates. Two kinds of grouping evolve: traveling pairs and opportunistic grouping, where individuals only aggregate when feeding. Grouping evolves because it allows individuals to better sense and deplete patches. Such enhanced patch depletion is particularly apparent on fragmented and partially depleted patches, which are especially difficult for solitary foragers to deplete. Solitary foragers often leave a patch prematurely because a whole patch cannot be observed directly. In groups, individuals that are still eating allow other individuals that inadvertently leave the patch, to return and continue feeding. For this information sharing a grouping tendency is sufficient and observing whether a neighbor is eating is not necessary. Grouping therefore leads to a release from individual sensing constraints and a shift in niche specialization, allowing individuals to better exploit partially depleted patches. Conclusions The evolved group foraging can be seen as cooperative in the sense that it leads to a mutually-beneficial synergy: together individuals can achieve more than on their own. This cooperation exists as a group-level process generated by the interaction between grouping and the environment. Thus we reveal how such a synergy can originate in evolution as a side-effect of grouping via multi-level selection. Here there is no cooperative dilemma as individuals cannot avoid producing information for their neighbors. This scenario may be a useful starting point for studying the evolution of further social and cooperative complexity. PMID:22093680

Night duty and decreased brain activity of medical residents: a wearable optical topography study

PubMed Central

Nishida, Masaki; Kikuchi, Senichiro; Miwakeichi, Fumikazu; Suda, Shiro

2017-01-01

ABSTRACT Background: Overwork, fatigue, and sleep deprivation due to night duty are likely to be detrimental to the performance of medical residents and can consequently affect patient safety. Objective: The aim of this study was to determine the possibility of deterioration of cerebral function of sleep-deprived, fatigued residents using neuroimaging techniques. Design: Six medical residents were instructed to draw blood from artificial vessels installed on the arm of a normal cooperator. Blood was drawn at a similar time of the day, before and after night duty. To assess sleep conditions during night duty, the participants wore actigraphy units throughout the period of night duty. Changes in cerebral hemodynamics, during the course of drawing blood, were measured using a wearable optical topography system. Results: The visual analogue scale scores after night duty correlated negatively with sleep efficiency during the night duty (ρ = −0.812, p = 0.050). The right prefrontal cortex activity was significantly decreased in the second trial after night duty compared with the first (p = 0.028). The extent of [oxy-Hb] decrease, indicating decreased activity, in the right dorsolateral prefrontal cortex correlated negatively with the Epworth sleepiness score after night duty (ρ = −0.841, p = 0.036). Conclusions: Sleep deprivation and fatigue after night duty, caused a decrease in the activity of the right dorsolateral prefrontal cortex of the residents, even with a relatively easy routine. This result implies that the brain activity of medical residents exposed to stress on night duty, although not substantially sleep-deprived, was impaired after the night duty, even though they apparently performed a simple medical technique appropriately. Reconsideration of the shift assignments of medical residents is strongly advised. Abbreviations: DLPFC: Dorsolateral prefrontal cortex; ESS: Epworth sleepiness scale; PSQI: Pittsburgh sleep quality index; ROI: Regions of interest; VAS: Visual analogue scale; WOT: Wearable optical topography PMID:28954586

Loss of Dok-1 and Dok-2 in mice causes severe experimental colitis accompanied by reduced expression of IL-17A and IL-22

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

Waseda, Masazumi; Arimura, Sumimasa; Shimura, Eri

Appropriate immune responses and mucosal barrier functions are required for the maintenance of intestinal homeostasis. Defects in this defense system may lead to inflammatory disorders such as inflammatory bowel disease. Downstream of tyrosine kinases 1 (Dok-1) and its closest homolog, Dok-2, are preferentially expressed in immune cells, and play essential roles in the negative regulation of multiple signaling pathways in both innate and adaptive immunity. However, the function of these proteins in intestinal homeostasis remained unclear. Here we show that Dok-1/-2 double knockout (DKO) mice were highly susceptible to dextran sodium sulfate (DSS)-induced colitis compared with Dok-1 or Dok-2 singlemore » KO and wild type (WT) mice. Furthermore, DSS-treated Dok-1/-2 DKO mice exhibited increased colonic tissue damage accompanied by reduced proliferation of the epithelial cells relative to WT controls, suggesting that Dok-1/-2 DKO mice have defects in the repair of intestinal epithelial lesions. In addition, the levels of the Th17 cytokines IL-17A and IL-22, which have protective roles in DSS-induced colitis, were reduced in DSS-treated Dok-1/-2 DKO mice compared with WT mice. Taken together, our results demonstrate that Dok-1 and Dok-2 negatively regulate intestinal inflammation, apparently through the induction of IL-17A and IL-22 expression. - Highlights: • Dok-1 and Dok-2 play a cooperative role in protection against DSS-induced colitis. • Dok-1/-2 double KO (DKO) mice show extensive ulceration of the colon after DSS treatment. • Proliferation of colonic epithelium is inhibited in DSS-treated Dok-1/-2 DKO mice. • Expression of IL-17A and IL-22 is reduced in the colon of DSS-treated Dok-1/-2 DKO mice.« less

Contrasting effects of climate on juvenile body size in a Southern Hemisphere passerine bird.

PubMed

Kruuk, Loeske E B; Osmond, Helen L; Cockburn, Andrew

2015-08-01

Despite extensive research on the topic, it has been difficult to reach general conclusions as to the effects of climate change on morphology in wild animals: in particular, the effects of warming temperatures have been associated with increases, decreases or stasis in body size in different populations. Here, we use a fine-scale analysis of associations between weather and offspring body size in a long-term study of a wild passerine bird, the cooperatively breeding superb fairy-wren, in south-eastern Australia to show that such variation in the direction of associations occurs even within a population. Over the past 26 years, our study population has experienced increased temperatures, increased frequency of heatwaves and reduced rainfall - but the mean body mass of chicks has not changed. Despite the apparent stasis, mass was associated with weather across the previous year, but in multiple counteracting ways. Firstly, (i) chick mass was negatively associated with extremely recent heatwaves, but there also positive associations with (ii) higher maximum temperatures and (iii) higher rainfall, both occurring in a period prior to and during the nesting period, and finally (iv) a longer-term negative association with higher maximum temperatures following the previous breeding season. Our results illustrate how a morphological trait may be affected by both short- and long-term effects of the same weather variable at multiple times of the year and that these effects may act in different directions. We also show that climate within the relevant time windows may not be changing in the same way, such that overall long-term temporal trends in body size may be minimal. Such complexity means that analytical approaches that search for a single 'best' window for one particular weather variable may miss other relevant information, and is also likely to make analyses of phenotypic plasticity and prediction of longer-term population dynamics difficult. © 2015 John Wiley & Sons Ltd.

Influence of different recombinant systems on the cooperativity exhibited by cytochrome P4503A4.

PubMed

Zhang, Z; Li, Y; Shou, M; Zhang, Y; Ngui, J S; Stearns, R A; Evans, D C; Baillie, T A; Tang, W

2004-05-01

1. The in vitro cooperativity exhibited by cytochrome P450 (CYP) 3A4 is influenced by the nature of the recombinant system in which the phenomenon is studied. Diclofenac, piroxicam and R-warfarin were used as model substrates, and quinidine was the effector. 2. The 5-, 5'- and 10-hydroxylation of diclofenac, piroxicam and R-warfarin, respectively, were enhanced five- to sevenfold by quinidine in human liver microsomal incubations. Whereas these cooperative drug interactions were apparent in incubations with CYP3A4 expressed in human lymphoblast cells, similar phenomena were not observed with the enzyme expressed in insect cells. 3. Insect cell microsomes were treated with a detergent and CYP3A4 was solubilized into a buffer medium. In incubations with CYP3A4 'freed' from its host membrane, the 5-hydroxylation of diclofenac increased with increasing quinidine concentrations, reaching a maximal eightfold elevation relative to controls. The metabolism of piroxicam and warfarin was similarly enhanced by quinidine. 4. Kinetically, enhancement by quinidine of the 5-hydroxylation of diclofenac in incubations with solubilized CYP3A4 was characterized by increases in the rate of metabolism with little change in the substrate-binding affinity. Conversely, the 3-hydroxylation of quinidine was not affected by diclofenac. 5. The data suggest that certain properties of CYP3A4 are masked by expression of the protein in insect cells and reinforce the concept that the enzyme possesses multiple binding domains. The absence of cooperative drug interactions with quinidine when CYP3A4 was expressed in insect cells might be due to an absence of enzyme conformation changes on quinidine binding, or the inability of quinidine to gain access to a putative effector-binding domain. 6. Caution should be exercised when comparing models for CYP3A4 cooperativity derived from different recombinant preparations of the enzyme.

Development cooperation in water and sanitation: is it based on the human rights framework?

PubMed

Brown, Colin; Heller, Léo

2017-07-01

The water and sanitation sector is verifiably receiving increased attention and funding through international development cooperation. Not least because of the way that it affects incentives and institutions in partner countries, development cooperation can have either positive or negative effects on human rights though. The consolidated frameworks for the human rights to water and sanitation is becoming linked to the international community's coordinated development efforts, as evidenced notably in the 2030 Agenda for Sustainable Development. However, a review of major funders' official policies for development cooperation in the sector suggests that many only partially endorse the frameworks for the human rights to water and sanitation. An observation of development cooperation flows to the sector allows the hypothesis to be advanced that worldwide inequalities in access to these services may be reduced through a full and clear application of the human rights framework in development cooperation activities. The article presents findings of this research and explores key stakes for development cooperation in the water and sanitation sector that are relevant for their ability to either negatively or positively contribute to the realization of human rights. Resumen El sector de agua y saneamiento ha recibido creciente atención y financiación a través de la cooperación internacional para el desarrollo. La cooperación para el desarrollo puede tener efectos tanto positivos cuanto negativos sobre los derechos humanos. El hito que consolida los derechos humanos al agua y al saneamiento están articulados a esfuerzos de cooperación para el desarrollo promovidos por la comunidad internacional, como se evidencia en la Agenda 2030 para el Desarrollo Sostenible. Sin embargo, una revisión de las políticas oficiales de los principales financiadores del sector sugiere que muchos de ellos aprueban solo parcialmente los hitos de los derechos humanos al agua y el saneamiento. La observación de los flujos de esta cooperación para el sector permite formular la hipótesis de que las desigualdades en el acceso a estos servicios en diferentes partes del mundo pueden reducirse con la aplicación completa y clara del marco de los derechos humanos en las actividades de cooperación para el desarrollo. El artículo presenta los resultados de esta investigación y explora los desafíos de la cooperación para el desarrollo del sector de agua y aguas residuales que son relevantes para impactar tanto negativamente cuanto positivamente a los derechos humanos.

ODP Site 1063 (Bermuda Rise) revisited: Oxygen isotopes, excursions and paleointensity in the Brunhes Chron

NASA Astrophysics Data System (ADS)

Channell, J. E. T.; Hodell, D. A.; Curtis, J. H.

2012-02-01

An age model for the Brunhes Chron of Ocean Drilling Program (ODP) Site 1063 (Bermuda Rise) is constructed by tandem correlation of oxygen isotope and relative paleointensity data to calibrated reference templates. Four intervals in the Brunhes Chron where paleomagnetic inclinations are negative for both u-channel samples and discrete samples are correlated to the following magnetic excursions with Site 1063 ages in brackets: Laschamp (41 ka), Blake (116 ka), Iceland Basin (190 ka), Pringle Falls (239 ka). These ages are consistent with current age estimates for three of these excursions, but not for "Pringle Falls" which has an apparent age older than a recently published estimate by ˜28 kyr. For each of these excursions (termed Category 1 excursions), virtual geomagnetic poles (VGPs) reach high southerly latitudes implying paired polarity reversals of the Earth's main dipole field, that apparently occurred in a brief time span (<2 kyr in each case), several times shorter than the apparent duration of regular polarity transitions. In addition, several intervals of low paleomagnetic inclination (low and negative in one case) are observed both in u-channel and discrete samples at ˜318 ka (MIS 9), ˜412 ka (MIS 11) and in the 500-600 ka interval (MIS 14-15). These "Category 2" excursions may constitute inadequately recorded (Category 1) excursions, or high amplitude secular variation.

Playful Learning and Montessori Education

ERIC Educational Resources Information Center

Lillard, Angeline S.

2013-01-01

Although Montessori education is often considered a form of playful learning, Maria Montessori herself spoke negatively about a major component of playful learning--pretend play, or fantasy--for young children. In this essay, the author discusses this apparent contradiction: how and why Montessori education includes elements of playful learning…

Annual survival and recruitment in a Ruby-throated Hummingbird population, excluding the effect of transient individuals

USGS Publications Warehouse

Hilton, B.; Miller, M.W.

2003-01-01

We estimated annual apparent survival, recruitment, and rate of population growth of breeding Ruby-throated Hummingbirds (Archilochus colubris), while controlling for transients, by using 18 years of capture-mark-recapture data collected during 1984-2001 at Hilton Pond Center for Piedmont Natural History near York, South Carolina. Resident males had lower apparent survival (0.30 +/- 0.05 SE) than females (0.43 +/- 0.04). Estimates of apparent survival did not differ by age. Point estimates suggested that newly banded males were less likely than females to be residents, but standard errors of these estimates overlapped (males: 0.60 +/- 0.14 SE; females: 0.67 +/- 0.09). Estimated female recruitment was 0.60 +/- 0.06 SE, meaning that 60% of adult females present in any given year had entered the population during the previous year. Our estimate for rate of change indicated the population of female hummingbirds was stable during the study period (1.04 +/- 0.04 SE). We suggest an annual goal of greater than or equal to 64 adult females and greater than or equal to 64 immature females released per banding area to enable rigorous future tests for effects of covariates on population dynamics. Development of a broader cooperating network of hummingbird banders in eastern North America could allow tests for regional or metapopulation dynamics in this species.

Raising Children Who Care.

ERIC Educational Resources Information Center

Kohn, Alfie

2000-01-01

Presents excerpt from Kohn's 1990 book, asserting that parents are most important to children and need to project a positive view of life. Argues that caring, the absence of physical punishment, guiding and explaining, cooperating, and taking children seriously are required to offset the pressure and negative values that a competitive culture…

Conflict and Fairness in Social Exchange

ERIC Educational Resources Information Center

Molm, Linda D.; Collett, Jessica L.; Schaefer, David R.

2006-01-01

Inherent to all social exchange relations are elements of both cooperation and competition. We develop and test a theoretical model which proposes that the relative salience of the competitive, conflictual elements of exchange mediate and explain the negative effects of negotiated exchange, as compared with reciprocal exchange, on actors'…

An Empirical Study about the Effect of Cultural Problematic on Organizational Learning in Alliances.

ERIC Educational Resources Information Center

Rodriguez, Sonia Dasi; Perez, Juan Francisco Martinez; del Val, Manuela Pardo

2003-01-01

A study of 19 small and medium-sized Spanish companies that established international cooperation agreements during 1997-1998 demonstrated that organizational cultures, company size, and national cultures significantly influence the learning that occurs. Negative influences include different work attitudes, languages, and communication systems. A…

Promoting Self-Esteem in a Caring Positive Classroom.

ERIC Educational Resources Information Center

Hodges, Linda; Wolf, Carolyn J.

Noting that low self-esteem negatively affects student achievement, this action research project implemented and evaluated a program for increasing student self-esteem through a caring and positive classroom environment incorporating cooperative learning and the use of praise and rewards. The targeted population consisted of fifth grade physical…

Cosmic Rays In The Magnetosphere, 2. Apparent Cut-off Rigidities and Coupling Functions

NASA Astrophysics Data System (ADS)

Dorman, L. I.; Danilova, O. A.; Iucci, N.; Parisi, M.; Ptitsyna, N. G.; Tyasto, M. I.; Villoresi, G.

We calculate the apparent cut-off rigidities along the survey Italy-Antarctica-Italy** on the basis of results of Danilova et al. (2001) on trajectory calculations for inclined cut- off rigidities at eight azimuths (through 45?) and five zeniths angles (through 15?) along the survey. For calculations of apparent cut-off rigidities we use also the infor- mation on integral multiplicities of secondary neutrons in dependence of zenith angle of incident primary cosmic ray particles, as theoretically computed. This information is based on the theoretical calculations of meson-nuclear cascades for primary protons with different rigidities arriving to the EarthSs atmosphere at different zenith angles (Dorman and Pakhomov, 1979). These results have been checked and normalized by using coupling functions obtained in the same survey [Dorman et al. (2000)]. The determined apparent cut-off rigidities have been compared with results obtained by Clem et al. (1997) and with those used by Dorman et al. (2000) computed by using vertical cut-off rigidities, for trajectories especially calculated for the survey. On the basis of the apparent cut-off rigidities along the latitude survey, the coupling functions for neutron monitor and bare neutron counters found by Dorman et al. (2000) are now determined more accurately. **Survey realized with logistic and financial support of the Italian Antarctic Program (PNRA) and with the co-operation of IFSI-CNR. REFERENCES: Clem, J.M., et al. J. Geophys. Res., 102, 26,919 (1997). Danilova, O.A., et al., Latitude survey in December 1996-March 1997, 1. Cut-off rigidities for different azimuth and zenith angles, Paper ST13, This issue (2001) Dorman L.I. and Pakhomov N.I., "The dependence of the integral generation multiplicity of neutron component at various depths in the atmosphere on zenith angle on primary particle in- cidence". Proc. 16-th ICRC, Kyoto, 4, 416-420 (1979) Dorman, L.I., et al., J. Geophys. Res. 105 , 21,047 (2000).

Weakly sheared active suspensions: hydrodynamics, stability, and rheology.

PubMed

Cui, Zhenlu

2011-03-01

We present a kinetic model for flowing active suspensions and analyze the behavior of a suspension subjected to a weak steady shear. Asymptotic solutions are sought in Deborah number expansions. At the leading order, we explore the steady states and perform their stability analysis. We predict the rheology of active systems including an activity thickening or thinning behavior of the apparent viscosity and a negative apparent viscosity depending on the particle type, flow alignment, and the anchoring conditions, which can be tested on bacterial suspensions. We find remarkable dualities that show that flow-aligning rodlike contractile (extensile) particles are dynamically and rheologically equivalent to flow-aligning discoid extensile (contractile) particles for both tangential and homeotropic anchoring conditions. Another key prediction of this work is the role of the concentration of active suspensions in controlling the rheological behavior: the apparent viscosity may decrease with the increase of the concentration.

Parahippocampal epilepsy with subtle dysplasia: A cause of "imaging negative" partial epilepsy.

PubMed

Pillay, Neelan; Fabinyi, Gavin C A; Myles, Terry S; Fitt, Gregory J; Berkovic, Samuel F; Jackson, Graeme D

2009-12-01

Lesion-negative refractory partial epilepsy is a major challenge in the assessment of patients for potential surgery. Finding a potential epileptogenic lesion simplifies assessment and is associated with good outcome. Here we describe imaging features of subtle parahippocampal dysplasia in five cases that were initially assessed as having imaging-negative frontal or temporal lobe epilepsy. We analyzed the clinical and imaging features of five patients with seizures from the parahippocampal region. Five patients had subtle but distinctive magnetic resonance imaging (MRI) abnormalities in the parahippocampal gyrus. This was a unilateral signal abnormality in the parahippocampal white matter extending into gray matter on heavily T(1)- and T(2)-weighted images with relative preservation of the gray-white matter boundary on T(1)-weighted volume sequences. Only one of these patients had typical electroclinical unilateral temporal lobe epilepsy (TLE); one mimicked frontal lobe epilepsy, two showed bitemporal seizures, and one had unlocalized partial seizures. All have had surgery; four are seizure-free (one has occasional auras only, follow-up 6 months to 10 years), and one has a >50% seizure reduction. Histopathologic evaluation suggested dysplastic features in the surgical specimens in all. In patients with lesion-negative partial epilepsy with frontal or temporal semiology, or in cases with apparent bitemporal seizures, subtle parahippocampal abnormalities should be carefully excluded. Recognizing the MRI findings of an abnormal parahippocampal gyrus can lead to successful surgery without invasive monitoring, despite apparently incongruent electroclinical features.

Charge mobility retrieval approach from apparent charge packet movements based on the negative differential resistance theory.

PubMed

Meng, Jia; Zhang, Yewen; Holé, Stéphane; Zheng, Feihu; An, Zhenlian

2018-04-12

Space charge migration characteristics play an important role in the evaluation of polymer insulation performance. However, an accurate description of charge carrier mobility in several typical insulating polymers such as polyethylene, polypropylene is currently not available. Recently, with the observation of a series of negative charge packet movements associated with the negative differential resistance characteristic of charge mobility in LDPE films, the extraction of charge mobility from the apparent charge packet movement has been attempted using appropriate methods. Based on the previous report of the successful derivation of charge mobility from experimental results using numerical methods, the present research improves the derivation accuracy and describes the details of the charge mobility derivation procedure. Back simulation results under several typical polarizing fields using the derived charge mobility are exhibited. The results indicate that both the NDR theory and the simulation models for the polyethylene materials are reasonable. A significant migration velocity difference between the charge carrier and the charge packet is observed. Back simulations of the charge packet under several typical polarizing fields using the obtained E-v curve show good agreement with the experimental results. The charge packet shapes during the migrations were also found to vary with the polarizing field.

Physical interpretation of antigravity

NASA Astrophysics Data System (ADS)

Bars, Itzhak; James, Albin

2016-02-01

Geodesic incompleteness is a problem in both general relativity and string theory. The Weyl-invariant Standard Model coupled to general relativity (SM +GR ), and a similar treatment of string theory, are improved theories that are geodesically complete. A notable prediction of this approach is that there must be antigravity regions of spacetime connected to gravity regions through gravitational singularities such as those that occur in black holes and cosmological bang/crunch. Antigravity regions introduce apparent problems of ghosts that raise several questions of physical interpretation. It was shown that unitarity is not violated, but there may be an instability associated with negative kinetic energies in the antigravity regions. In this paper we show that the apparent problems can be resolved with the interpretation of the theory from the perspective of observers strictly in the gravity region. Such observers cannot experience the negative kinetic energy in antigravity directly, but can only detect in and out signals that interact with the antigravity region. This is no different from a spacetime black box for which the information about its interior is encoded in scattering amplitudes for in/out states at its exterior. Through examples we show that negative kinetic energy in antigravity presents no problems of principles but is an interesting topic for physical investigations of fundamental significance.

Influence of processing conditions on apparent viscosity and system parameters during extrusion of distiller's dried grains-based snacks.

PubMed

Singha, Poonam; Muthukumarappan, Kasiviswanathan; Krishnan, Padmanaban

2018-01-01

A combination of different levels of distillers dried grains processed for food application (FDDG), garbanzo flour and corn grits were chosen as a source of high-protein and high-fiber extruded snacks. A four-factor central composite rotatable design was adopted to study the effect of FDDG level, moisture content of blends, extrusion temperature, and screw speed on the apparent viscosity, mass flow rate or MFR, torque, and specific mechanical energy or SME during the extrusion process. With increase in the extrusion temperature from 100 to 140°C, apparent viscosity, specific mechanical energy, and torque value decreased. Increase in FDDG level resulted in increase in apparent viscosity, SME and torque. FDDG had no significant effect (p > .5) on mass flow rate. SME also increased with increase in the screw speed which could be due to the higher shear rates at higher screw speeds. Screw speed and moisture content had significant negative effect ( p  <   .05) on the torque. The apparent viscosity of dough inside the extruder and the system parameters were affected by the processing conditions. This study will be useful for control of extrusion process of blends containing these ingredients for the development of high-protein high-fiber extruded snacks.

A functional MRI study on how oxytocin affects decision making in social dilemmas: Cooperate as long as it pays off, aggress only when you think you can win.

PubMed

Lambert, Bruno; Declerck, Carolyn H; Boone, Christophe; Parizel, Paul M

2017-08-01

We investigate if the neuropeptide oxytocin (OT), known to moderate social behaviour, influences strategic decision making in social dilemmas by facilitating the integration of incentives and social cues. Participants (N=29) played two economic games with different incentive structures in the fMRI scanner after receiving OT or placebo (following a double blind, within-subject design). Pictures of angry or neutral faces (the social cues) were displayed alongside the game matrices. Consistent with a priori hypotheses based on the modulatory role of OT in mesolimbic dopaminergic brain regions, the results indicate that, compared to placebo, OT significantly increases the activation of the nucleus accumbens during an assurance (coordination) game that rewards mutual cooperation. This increases appetitive motivation so that cooperative behaviour is facilitated for risk averse individuals. OT also significantly attenuates the amygdala, thereby reducing the orienting response to social cues. The corresponding change in behaviour is only apparent in the chicken (or anti-coordination) game, where aggression is incentivized but fatal if the partner also aggresses. Because of this ambiguity, decision making can be improved by additional information, and OT steers decisions in the chicken game in accordance with the valence of the facial cue: aggress when face is neutral; retreat when it is angry. Through its combined influence on amygdala and nucleus accumbens, OT improves the selection of a cooperative or aggressive strategy in function of the best match between the incentives of the game and the social cues present in the decision environment. Copyright © 2017 Elsevier Inc. All rights reserved.

A report on the use of thermal scanner data in an operational program for monitoring apparent rooftop temperatures

NASA Technical Reports Server (NTRS)

Bjorklund, J.; Schmer, F. A.; Isakson, R. E.

1975-01-01

CENGAS, a division of Central Telephone and Utilities Corporation in cooperation with the Remote Sensing Institute, South Dakota State University, is using airborne thermal scanner data to monitor relative rooftop temperatures. Four Nebraska communities and one South Dakota community were surveyed by the Remote Sensing Institute for CENGAS. Thermal scanner data were converted to a film format and the resultant imagery has been successfully employed by CENGAS. The program places emphasis on heat losses resulting from inadequate home insulation, offers CENGAS customers the opportunity to observe a thermogram of their rooftop, and assists homeowners in evaluating insulation needs.

Commentary: further points for dialogue on the death penalty, the church, and our profession.

PubMed

Young, John L

2008-01-01

The invitation to dialogue on the subject of the death penalty is both important for our time and challenging in what it calls forth from us. It forces us to recognize both the fundamental privacy of individual intention and the potential breadth of its reach. It can deepen our sense of responsibility for what happens to others on our account, even in the apparent absence of intention. The astonishing power of the spoken word should be harnessed by cooperative dialogue to focus its consequences more sharply on the demands of justice. We need dialogue to attend faithfully to our deepest obligations and longings.

Incidence of stomach cancer in oman and the other gulf cooperation council countries.

PubMed

Al-Mahrouqi, Haitham; Parkin, Lianne; Sharples, Katrina

2011-07-01

Stomach cancer is the most common cancer among males in Oman and the second most frequent among females from 1997 to 2007. Reports have suggested the rate is higher in Oman than in the other GCC countries. This study aims to describe the epidemiology of stomach cancer in Oman and to explore the apparent differences in the incidence of stomach cancer between Oman and the other Gulf Cooperation Council (GCC) countries. Data were obtained from the Omani National Cancer Registry (1997 - 2007) and from Gulf Centre for Cancer Registration reports (1998 - 2004). The annual average age-adjusted incidence rates for stomach cancer in Oman were 10.1 per 100,000 for males and 5.6 per 100,000 for females between 1997 and 2007. The age-adjusted incidence varied by region within Oman, and the incidence rate was higher in Oman than in most other GCC countries between 1998 and 2004. Further investigation of the completeness and accuracy of cancer registration is essential for exploration of variations in stomach cancer rates in the GCC countries.

Incidence of Stomach Cancer in Oman and the Other Gulf Cooperation Council Countries

PubMed Central

Al-Mahrouqi, Haitham; Parkin, Lianne; Sharples, Katrina

2011-01-01

Objectives Stomach cancer is the most common cancer among males in Oman and the second most frequent among females from 1997 to 2007. Reports have suggested the rate is higher in Oman than in the other GCC countries. This study aims to describe the epidemiology of stomach cancer in Oman and to explore the apparent differences in the incidence of stomach cancer between Oman and the other Gulf Cooperation Council (GCC) countries. Methods Data were obtained from the Omani National Cancer Registry (1997 - 2007) and from Gulf Centre for Cancer Registration reports (1998 - 2004). Results The annual average age-adjusted incidence rates for stomach cancer in Oman were 10.1 per 100,000 for males and 5.6 per 100,000 for females between 1997 and 2007. The age-adjusted incidence varied by region within Oman, and the incidence rate was higher in Oman than in most other GCC countries between 1998 and 2004. Conclusion Further investigation of the completeness and accuracy of cancer registration is essential for exploration of variations in stomach cancer rates in the GCC countries. PMID:22043430

A model of risk and mental state shifts during social interaction.

PubMed

Hula, Andreas; Vilares, Iris; Lohrenz, Terry; Dayan, Peter; Montague, P Read

2018-02-01

Cooperation and competition between human players in repeated microeconomic games offer a window onto social phenomena such as the establishment, breakdown and repair of trust. However, although a suitable starting point for the quantitative analysis of such games exists, namely the Interactive Partially Observable Markov Decision Process (I-POMDP), computational considerations and structural limitations have limited its application, and left unmodelled critical features of behavior in a canonical trust task. Here, we provide the first analysis of two central phenomena: a form of social risk-aversion exhibited by the player who is in control of the interaction in the game; and irritation or anger, potentially exhibited by both players. Irritation arises when partners apparently defect, and it potentially causes a precipitate breakdown in cooperation. Failing to model one's partner's propensity for it leads to substantial economic inefficiency. We illustrate these behaviours using evidence drawn from the play of large cohorts of healthy volunteers and patients. We show that for both cohorts, a particular subtype of player is largely responsible for the breakdown of trust, a finding which sheds new light on borderline personality disorder.

Continuous Cash Benefit (BCP) for disabled individuals: access barriers and intersectoral gaps.

PubMed

Vaitsman, Jeni; Lobato, Lenaura de Vasconcelos Costa

2017-11-01

The 1988 Constitution approved the Continuous Cash Benefit (BCP) directed to elders and disabled persons with a household per capita income of 25% of the minimum wage, and around 4 million people received this benefit in 2015. The design of BPC for disabled persons involves organizations of social security, social welfare and health. This paper discusses how some intersectoral coordination mechanisms gaps between these areas produce access barriers to potential beneficiaries. Results stem from a qualitative study performed with physicians, administrative staff and social workers from the National Institute of Social Security (INSS) and of the Social Welfare Reference Center (CRAS) in three municipalities of different Brazilian regions. Intersectoral coordination and cooperation are more structured at the Federal level. At the local level, they rely on informal and horizontal initiatives, which produce immediate but discontinuous solutions. The role of the CRAS remains contingent on the implementation. The need to establish institutionalized mechanisms for coordination and cooperation between social welfare, health and social insurance to improve the implementation and reduce barriers to access to the BCP is apparent.

A model of risk and mental state shifts during social interaction

PubMed Central

Vilares, Iris

2018-01-01

Cooperation and competition between human players in repeated microeconomic games offer a window onto social phenomena such as the establishment, breakdown and repair of trust. However, although a suitable starting point for the quantitative analysis of such games exists, namely the Interactive Partially Observable Markov Decision Process (I-POMDP), computational considerations and structural limitations have limited its application, and left unmodelled critical features of behavior in a canonical trust task. Here, we provide the first analysis of two central phenomena: a form of social risk-aversion exhibited by the player who is in control of the interaction in the game; and irritation or anger, potentially exhibited by both players. Irritation arises when partners apparently defect, and it potentially causes a precipitate breakdown in cooperation. Failing to model one’s partner’s propensity for it leads to substantial economic inefficiency. We illustrate these behaviours using evidence drawn from the play of large cohorts of healthy volunteers and patients. We show that for both cohorts, a particular subtype of player is largely responsible for the breakdown of trust, a finding which sheds new light on borderline personality disorder. PMID:29447153

PLATFORM SESSION "IMMUNOTOXICOLOGY", SOCIETY OF TOXICOLOGY 45TH ANNUAL MEETING, MARCH 5-9, 2006, SAN DIEGO, CA

EPA Science Inventory

For many years the primary endpoints for evaluating the toxicity of xenobiotics were carcinogenicity and mutagenicity. However, it gradually became apparent that exposure to chemicals at levels lower than those shown to be directly carcinogenic may negatively impact other facets...

An Overview of the Results on Consumption, Health, and Social Behavior

ERIC Educational Resources Information Center

Baumol, William J.

1974-01-01

The consumption effects, health, social activities, and family size of families eligible for or receiving subsidies such as negative income tax (Graduated Work Incentive Experiment-New Jersey, Pennsylvania) did not change significantly; however, the support program apparently produced an improvement in housing standards and an increase in home…

Wake up, because Math Matters

ERIC Educational Resources Information Center

Gilpin, Jeanny

2010-01-01

This article presents the author's story, as a teacher, about building a Math Matters club and discusses why her students arrived at school before first bell to participate enthusiastically. The author's students seemed to have a negative attitude about math. In giving that stirring motivational speech, she apparently overlooked one important…

Regular and Special Educators: Handicap Integration Attitudes and Implications for Consultants.

ERIC Educational Resources Information Center

Gans, Karen D.

1985-01-01

One-hundred twenty-eight regular and 133 special educators responded to a questionnaire on mainstreaming. The two groups were similiar in their attitudes. Regular educators displayed more negative attitudes, but the differences rarely reached significance. Group differences became more apparent when attitudes concerning specific handicapping…

Moral Disengagement in Science and Business Students: An Exploratory Study

ERIC Educational Resources Information Center

Cory, Suzanne N.

2015-01-01

Cases of unethical business practices and technical failures have been extensively reported. It seems that actions are often taken by individuals with little apparent concern for those affected by their negative outcomes, which can be described as moral disengagement. This study investigates levels of moral disengagement demonstrated by business…

Raising Achievement through Inclusion

ERIC Educational Resources Information Center

Persson, Elisabeth

2013-01-01

In 2007, Swedish authorities introduced open publication of comparisons of students' results at the end of compulsory school. In this study, we investigated a municipality that had succeeded in breaking a negative trend from a bottom position in the ranking in 2007 to a top position in 2010, apparently through inclusive practices. The purpose of…

Through the Looking Glass: Symmetry in Behavioral Principles?

ERIC Educational Resources Information Center

Marr, M. Jackson

2006-01-01

In this article, the author discusses and presents seven possibilities that describe how symmetry principles are reflected in behavior analysis. First, if there are apparently no functional distinctions to be made between positive and negative reinforcement, then reinforcer effectiveness (by various measures) is invariant under a simple inversion…

Op. Amps in Power Amplification: A Laboratory Exercise on Feedback.

ERIC Educational Resources Information Center

Borcherds, P. H.

1984-01-01

To demonstrate negative feedback a power amplifier is constructed from an operational amplifier together with a complementary pair of transistors as an output stage. The amplifier is developed and tested stage by stage, and at each stage the defects apparent at the previous stage are eliminated. (JN)

Geohydrology of test well USW H-1, Yucca Mountain, Nye County, Nevada

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

Rush, F.E.; Thordarson, W.; Pyles, D.G.

This report contains the results of hydraulic testing, hydrologic monitoring, and geophysical logging of test well USW H-1, one of several wells drilled in the southwestern part of the Nevada Test Site in cooperation with the US Department of Energy for investigations related to the isolation of high-level radioactive wastes. All rocks penetrated by the well to a total depth of 1829 meters were of volcanic origin and of Tertiary age. Hydraulic head in the zone 688 to 741 meters below land surface was 730 meters above sea level and at a depth of 572 meters below land surface. Deepermore » zones had hydraulic heads of 781 meters above sea level or higher, indicating an upward component of ground-water flow at the site. The most transmissive zone, with an apparent transmissivity of about 150 meters squared per day, is in the Prow Pass Member of the Crater Flat Tuff in the depth range from 572 to 688 meters below land surface. The remainder of the penetrated rocks in the saturated zone, 688 to 1829 meters, has an apparent transmissivity of about 1 meter squared per day. The most transmissive part of the lower depth range is in the Bullfrog Member of the Crater Flat Tuff in the depth interval from 736 to 741 meters. The apparent hydraulic conductivity of the rocks in this lower depth interval from 688 to 1829 meters commonly ranges between 10{sup -4} and 10{sup -7} meter per day. Water chemistry is typical of tuffaceous rocks of southern Nevada. The water is a sodium bicarbonate type and has an apparent age of 12,000 to 13,000 years before present, as determined by carbon-14 dating.« less

Bim-mediated apoptosis is not necessary for thymic negative selection to ubiquitous self-antigens.

PubMed

Hu, Qian; Sader, Alyssa; Parkman, Julia C; Baldwin, Troy A

2009-12-15

T cell education in the thymus is critical for establishing a functional, yet self-tolerant, T cell repertoire. Negative selection is a key process in enforcing self-tolerance. There are many questions that surround the mechanism of negative selection, but it is currently held that apoptosis initiated by Bim and/or Nur77 is critical for negative selection. Recent studies, however, have questioned the necessity of Bim in maintaining both central and peripheral T cell tolerance. To reconcile these apparently contradictory findings, we examined the role of Bim in negative selection in the well-characterized, physiological HY(cd4) mouse model. We found that while Bim expression was required for CD4(+)CD8(+) double-positive thymocyte apoptosis, it was not required for negative selection. Furthermore, Bim deficiency did not alter the frequency or affinity of male reactive cells that escape negative selection in an oligoclonal repertoire. Collectively, these studies indicate that negative selection occurs efficiently in the absence of apoptosis and suggest that the current paradigm of negative selection requiring apoptosis be revisited.

The influence of initial conditions on dispersion and reactions

NASA Astrophysics Data System (ADS)

Wood, B. D.

2016-12-01

In various generalizations of the reaction-dispersion problem, researchers have developed frameworks in which the apparent dispersion coefficient can be negative. Such dispersion coefficients raise several difficult questions. Most importantly, the presence of a negative dispersion coefficient at the macroscale leads to a macroscale representation that illustrates an apparent decrease in entropy with increasing time; this, then, appears to be in violation of basic thermodynamic principles. In addition, the proposition of a negative dispersion coefficient leads to an inherently ill-posed mathematical transport equation. The ill-posedness of the problem arises because there is no unique initial condition that corresponds to a later-time concentration distribution (assuming that if discontinuous initial conditions are allowed). In this presentation, we explain how the phenomena of negative dispersion coefficients actually arise because the governing differential equation for early times should, when derived correctly, incorporate a term that depends upon the initial and boundary conditions. The process of reactions introduces a similar phenomena, where the structure of the initial and boundary condition influences the form of the macroscopic balance equations. When upscaling is done properly, new equations are developed that include source terms that are not present in the classical (late-time) reaction-dispersion equation. These source terms depend upon the structure of the initial condition of the reacting species, and they decrease exponentially in time (thus, they converge to the conventional equations at asymptotic times). With this formulation, the resulting dispersion tensor is always positive-semi-definite, and the reaction terms directly incorporate information about the state of mixedness of the system. This formulation avoids many of the problems that would be engendered by defining negative-definite dispersion tensors, and properly represents the effective rate of reaction at early times.

Fashion, Cooperation, and Social Interactions

PubMed Central

Cao, Zhigang; Gao, Haoyu; Qu, Xinglong; Yang, Mingmin; Yang, Xiaoguang

2013-01-01

Fashion plays such a crucial rule in the evolution of culture and society that it is regarded as a second nature to the human being. Also, its impact on economy is quite nontrivial. On what is fashionable, interestingly, there are two viewpoints that are both extremely widespread but almost opposite: conformists think that what is popular is fashionable, while rebels believe that being different is the essence. Fashion color is fashionable in the first sense, and Lady Gaga in the second. We investigate a model where the population consists of the afore-mentioned two groups of people that are located on social networks (a spatial cellular automata network and small-world networks). This model captures two fundamental kinds of social interactions (coordination and anti-coordination) simultaneously, and also has its own interest to game theory: it is a hybrid model of pure competition and pure cooperation. This is true because when a conformist meets a rebel, they play the zero sum matching pennies game, which is pure competition. When two conformists (rebels) meet, they play the (anti-) coordination game, which is pure cooperation. Simulation shows that simple social interactions greatly promote cooperation: in most cases people can reach an extraordinarily high level of cooperation, through a selfish, myopic, naive, and local interacting dynamic (the best response dynamic). We find that degree of synchronization also plays a critical role, but mostly on the negative side. Four indices, namely cooperation degree, average satisfaction degree, equilibrium ratio and complete ratio, are defined and applied to measure people’s cooperation levels from various angles. Phase transition, as well as emergence of many interesting geographic patterns in the cellular automata network, is also observed. PMID:23382799

The dynamic nature of interrogation.

PubMed

Kelly, Christopher E; Miller, Jeaneé C; Redlich, Allison D

2016-06-01

Building on a substantial body of literature examining interrogation methods employed by police investigators and their relationship to suspect behaviors, we analyzed a sample of audio and video interrogation recordings of individuals suspected of serious violent crimes. Existing survey research has focused on the tactics reportedly used, at what rate, and under what conditions; observational studies detail which methods are actually employed. With a few notable exceptions, these foundational studies were static examinations of interrogation methods that documented the absence or presence of various approaches. In the present study, we cast interrogation as a dynamic phenomenon and code the recordings in 5-min intervals to examine how interrogation methods and suspect cooperation change over time. Employing the interrogation taxonomy framework, particularly 4 discrete domains-rapport and relationship building, emotion provocation, presentation of evidence, and confrontation/competition-we found that the emphasis of the domains varied across interrogations and were significantly different when suspects confessed versus when they denied involvement. In regression models, suspect cooperation was positively influenced by the rapport and relationship building domain, though it was negatively impacted by presentation of evidence and confrontation/competition. Moreover, we found that the negative effects of confrontation/competition on suspect cooperation lasted for up to 15 min. The implications of the findings for practice and future research include the benefits of a rapport-based approach, the deleterious effects of accusatorial methods, and the importance of studying when, not just if, certain interrogation techniques are employed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Teachers' Expectations and Self-Efficacy for Working with Bullies and Victims

ERIC Educational Resources Information Center

Skinner, Ann T.; Babinski, Leslie M.; Gifford, Elizabeth J.

2014-01-01

Bullying is a significant concern in schools, and both bullies and victims are at risk for negative outcomes. In this study, 239 sixth-grade teachers completed questionnaires about their perceptions of four components of school climate: high-risk student behaviors, school-wide barriers to learning, principal support, and cooperation among…

Why Can't We Be Deweyan Citizens?

ERIC Educational Resources Information Center

Webber, Julie

2001-01-01

This essay focuses on what happens to the individual's attitude toward community when events that pass into the category of uncanny become seemingly commonplace and are experienced as direct assaults on the logic of community and cooperation. It refers to Nietzsche's views on the negative, and Dewey's views on the positive doctrine of motivation.…

Biological Impact of the Chippewa Off-Reservation Treaty Harvest, 1983-1989.

ERIC Educational Resources Information Center

Busiahn, Thomas R.

1991-01-01

In Wisconsin, Chippewa tribal harvests have not had a negative impact on populations of lake trout, walleye, fishers, and white-tailed deer. The treaty rights controversy is fueled by uncertainties about the status of natural resources, uncertainties that could be addressed by cooperative state-tribal wildlife management programs. (SV)

PROJECT CONCERN--A CASE STUDY IN URBAN-SUBURBAN COOPERATION. POSITION PAPER.

ERIC Educational Resources Information Center

MAHAN, THOMAS W.

PROJECT CONCERN SEEKS TO DEMONSTRATE THAT THE LOWER ACHIEVEMENT OF DISADVANTAGED STUDENTS IS AN "ARTIFACT" OF A NEGATIVE INTERACTION BETWEEN THE SLUM NEIGHBORHOOD AND THE SLUM SCHOOL. TO COUNTERACT THIS EFFECT, THE PROJECT HAS BUSED OVER 250 INNER CITY MINORITY GROUP CHILDREN, FROM KINDERGARTEN THROUGH FIFTH GRADE, TO FIVE MIDDLE CLASS…

Gossip as an alternative for direct observation in games of indirect reciprocity

PubMed Central

Sommerfeld, Ralf D.; Krambeck, Hans-Jürgen; Semmann, Dirk; Milinski, Manfred

2007-01-01

Communication about social topics is abundant in human societies, and many functions have been attributed to such gossiping. One of these proposed functions is the management of reputations. Reputation by itself has been shown to have a strong influence on cooperation dynamics in games of indirect reciprocity, and this notion helps to explain the observed high level of cooperation in humans. Here we designed a game to test a widespread assumption that gossip functions as a vector for the transmission of social information. This empirical study (with 14 groups of nine students each) focuses on the composition of gossip, information transfer by gossip, and the behavior based on gossip information. We show that gossip has a strong influence on the resulting behavior even when participants have access to the original information (i.e., direct observation) as well as gossip about the same information. Thus, it is evident that gossip has a strong manipulative potential. Furthermore, gossip about cooperative individuals is more positive than gossip about uncooperative individuals, gossip comments transmit social information successfully, and cooperation levels are higher when people encounter positive compared with negative gossip. PMID:17947384

Interactions between perceived emotions and executive attention in an interpersonal game

PubMed Central

Madrid, Eduardo; Tudela, Pío

2013-01-01

The emotions displayed by others can be cues to predict their behavior. Happy expressions are usually linked to positive consequences, whereas angry faces are associated with probable negative outcomes. However, there are situations in which the expectations we generate do not hold. Here, control mechanisms must be put in place. We designed an interpersonal game in which participants received good or bad economic offers from several partners. A cue indicated whether the emotion of their partner could be trusted or not. Trustworthy partners with happy facial expressions were cooperative, and angry partners did not cooperate. Untrustworthy partners cooperated when their expression was angry and did not cooperate when they displayed a happy emotion. Event-Related Potential (ERP) results showed that executive attention already influenced the frontal N1. The brain initially processed emotional expressions regardless of their contextual meaning but by the N300, associated to affective evaluation, emotion was modulated by control mechanisms. Our results suggest a cascade of processing that starts with the instantiation of executive attention, continues by a default processing of emotional features and is then followed by an interaction between executive attention and emotional factors before decision-making and motor stages. PMID:22842814

Effects of ecstasy on cooperative behaviour and perception of trustworthiness: a naturalistic study.

PubMed

Stewart, L H; Ferguson, B; Morgan, C J A; Swaboda, N; Jones, L; Fenton, R; Wall, M B; Curran, H V

2014-11-01

Acute recreational use of 3,4-methylenedioxymethamphetamine (MDMA; 'ecstasy') can promote pro-social effects which may alter interpersonal perceptions. To explore such effects, this study investigated whether acute recreational use of ecstasy was associated with changes in individual perception of trustworthiness of people's faces and co-operative behaviours. An independent group, repeated measures design was used in which 17 ecstasy users were tested on the night of drug use (day 0) and again three days later (day 3); 22 controls were tested on parallel days. On each day, participants rated the trustworthiness of 66 faces, carried out three co-operative behaviour tasks (public good; dictator; ultimatum game) and completed mood self-ratings. Acute ecstasy use was associated with increased face trustworthiness ratings and increased cooperative behaviour on the dictator and ultimatum games; on day 3 there were no group differences on any task. Self-ratings showed the standard acute ecstasy effects (euphoria, energy, jaw clenching) with negative effects (less empathy, compassion, more distrust, hostility) emerging on day 3. Our findings of increased perceived trustworthiness and co-operative behaviours following use of ecstasy suggest that a single dose of the drug enhances aspects of empathy. This may in turn contribute to its popularity as a recreational drug and potentially to its enhancement of the therapeutic alliance in psychotherapy. © The Author(s) 2014.

Impact of shill intervention on the evolution of cooperation

NASA Astrophysics Data System (ADS)

Sun, Changhao; Duan, Haibin

2015-09-01

The practical significance of effective intervention in collective behavior has its roots not only in frequent migration in the modern society, but also in the actual demands of real-world applications for system efficiency improvement. Within the framework of soft control, this paper focuses on an evolutionary public goods game staged on a scale free network and explores the dependence of the evolution of cooperation on the intervention of a fraction of shills, who follow the Fixed-Cost-per-Player paradigm while the locals follow the Fixed-Cost-per-Game paradigm. We demonstrate that higher cooperation levels and better social welfare could be simultaneously induced by tuning the distribution coefficient α, where desirable outcomes are associated with large α > 0 for tense dilemmas while small α < 0 leads to satisfactory results when the enhancement factor γ increases. Moreover, we observe a transition of the composition of equilibrium cooperators from full dominance of shills to co-existence of shills and locals, and the boundary has a positive correlation with α. These results are somehow affected when we attenuate the heterogeneity of the network by relating individual fitness to payoffs averaged over its connectivity. Our findings may not only shed some light on the mechanism behind the evolution of cooperation from the perspective of external intervention, but also provide a feasible way to effectively intervene in the evolutionary outcomes of negative scenarios.

Variation in Behavioral Reactivity Is Associated with Cooperative Restraint Training Efficiency

PubMed Central

Bliss-Moreau, Eliza; Moadab, Gilda

2016-01-01

Training techniques that prepare laboratory animals to participate in testing via cooperation are useful tools that have the potential to benefit animal wellbeing. Understanding how animals systematically vary in their cooperative training trajectories will help trainers to design effective and efficient training programs. In the present report we document an updated method for training rhesus monkeys to cooperatively participate in restraint in a ‘primate chair.’ We trained 14 adult male macaques to raise their head above a yoke and accept yoke closure in an average of 6.36 training days in sessions that lasted an average of 10.52 min. Behavioral observations at 2 time points prior to training (approximately 3 y and 1.3 y prior) were used to quantify behavioral reactivity directed toward humans and toward other macaques. Individual differences in submissive–affiliative reactivity to humans but not reactivity toward other monkeys were related to learning outcomes. Macaques that were more reactive to humans were less willing to participate in training, were less attentive to the trainer, were more reactive during training sessions, and required longer training sessions, longer time to yoke, and more instances of negative reinforcement. These results suggest that rhesus macaques can be trained to cooperate with restraint rapidly and that individual difference data can be used to structure training programs to accommodate variation in animal temperament. PMID:26817979

Some mechanistic requirements for major transitions

PubMed Central

2016-01-01

Major transitions in nature and human society are accompanied by a substantial change towards higher complexity in the core of the evolving system. New features are established, novel hierarchies emerge, new regulatory mechanisms are required and so on. An obvious way to achieve higher complexity is integration of autonomous elements into new organized systems whereby the previously independent units give up their autonomy at least in part. In this contribution, we reconsider the more than 40 years old hypercycle model and analyse it by the tools of stochastic chemical kinetics. An open system is implemented in the form of a flow reactor. The formation of new dynamically organized units through integration of competitors is identified with transcritical bifurcations. In the stochastic model, the fully organized state is quasi-stationary whereas the unorganized state corresponds to a population with natural selection. The stability of the organized state depends strongly on the number of individual subspecies, n, that have to be integrated: two and three classes of individuals, and , readily form quasi-stationary states. The four-membered deterministic dynamical system, , is stable but in the stochastic approach self-enhancing fluctuations drive it into extinction. In systems with five and more classes of individuals, , the state of cooperation is unstable and the solutions of the deterministic ODEs exhibit large amplitude oscillations. In the stochastic system self-enhancing fluctuations lead to extinction as observed with . Interestingly, cooperative systems in nature are commonly two-membered as shown by numerous examples of binary symbiosis. A few cases of symbiosis of three partners, called three-way symbiosis, have been found and were analysed within the past decade. Four-way symbiosis is rather rare but was reported to occur in fungus-growing ants. The model reported here can be used to illustrate the interplay between competition and cooperation whereby we obtain a hint on the role that resources play in major transitions. Abundance of resources seems to be an indispensable prerequisite of radical innovation that apparently needs substantial investments. Economists often claim that scarcity is driving innovation. Our model sheds some light on this apparent contradiction. In a nutshell, the answer is: scarcity drives optimization and increase in efficiency but abundance is required for radical novelty and the development of new features. This article is part of the themed issue ‘The major synthetic evolutionary transitions’. PMID:27431517

A structured population model suggests that long life and post-reproductive lifespan promote the evolution of cooperation.

PubMed

Ross, Caitlin; Rychtář, Jan; Rueppell, Olav

2015-03-21

Social organization correlates with longevity across animal taxa. This correlation has been explained by selection for longevity by social evolution. The reverse causality is also conceivable but has not been sufficiently considered. We constructed a simple, spatially structured population model of asexually reproducing individuals to study the effect of temporal life history structuring on the evolution of cooperation. Individuals employed fixed strategies of cooperation or defection towards all neighbours in a basic Prisoner's Dilemma paradigm. Individuals aged and transitioned through different life history stages asynchronously without migration. An individual's death triggered a reproductive event by one immediate neighbour. The specific neighbour was chosen probabilistically according to the cumulative payoff from all local interactions. Varying the duration of pre-reproductive, reproductive, and post-reproductive life history stages, long-term simulations allowed a systematic evaluation of the influence of the duration of these specific life history stages. Our results revealed complex interactions among the effects of the three basic life history stages and the benefit to defect. Overall, a long post-reproductive stage promoted the evolution of cooperation, while a prolonged pre-reproductive stage has a negative effect. In general, the total length of life also increased the probability of the evolution of cooperation. Thus, our specific model suggests that the timing of life history transitions and total duration of life history stages may affect the evolution of cooperative behaviour. We conclude that the causation of the empirically observed association of life expectancy and sociality may be more complex than previously realized. Copyright © 2015 Elsevier Ltd. All rights reserved.

A structured population model suggests that long life and post-reproductive lifespan promote the evolution of cooperation

PubMed Central

Ross, Caitlin; Rychtář, Jan; Rueppell, Olav

2015-01-01

Social organization correlates with longevity across animal taxa. This correlation has been explained by selection for longevity by social evolution. The reverse causality is also conceivable but has not been sufficiently considered. We constructed a simple, spatially structured population model of asexually reproducing individuals to study the effect of temporal life history structuring on the evolution of cooperation. Individuals employed fixed strategies of cooperation or defection towards all neighbours in a basic Prisoner’s Dilemma paradigm. Individuals aged and transitioned through different life history stages asynchronously without migration. An individual’s death triggered a reproductive event by one immediate neighbour. The specific neighbour was chosen probabilistically according to the cumulative payoff from all local interactions. Varying the duration of pre-reproductive, reproductive, and post-reproductive life history stages, long-term simulations allowed a systematic evaluation of the influence of the duration of these specific life history stages. Our results revealed complex interactions among the effects of the three basic life history stages and the benefit to defect. Overall, a long post-reproductive stage promoted the evolution of cooperation, while a prolonged pre-reproductive stage has a negative effect. In general, the total length of life also increased the probability of the evolution of cooperation. Thus, our specific model suggests that the timing of life history transitions and total duration of life history stages may affect the evolution of cooperative behaviour. We conclude that the causation of the empirically observed association of life expectancy and sociality may be more complex than previously realized. PMID:25637763

Benjamin Franklin's Evolving Views on Race and Ethnicity

ERIC Educational Resources Information Center

Lapham, Steven S.; Saunders, Andrew

2005-01-01

More telling than his negative comments about Germans' shortcomings, was Benjamin Franklin's early attitude to slavery. In the 1730s, Franklin's newspaper, the Philadelphia Gazette, carried advertisements for black slaves, and he himself apparently participated in the slave trade, acting at the very least as the contact man for buyers and sellers.…

Phrynosoma hernandesi (Greater Short-Horned Lizard). Commensalism

USGS Publications Warehouse

Yackel, Amy; Adams, Rod D.; Skagen, Susan K.; Martin, Daniel J.

2016-01-01

Commensalism is a relationship between two organisms whereby one benefits without negatively affecting the other. Like other horned lizards, Phyrnosoma hernandesi feeds primarily on ants, but will take other insects (Powell and Russell 1983. Can. J. Zool. 62:428–440). Here we describe apparent com-mensalism between P. hernandesi and Lark Buntings (Calamo-spiza melanocorys).

Mood Management during the Menstrual Cycle through Selective Exposure to Television.

ERIC Educational Resources Information Center

Weaver, James B., III; Laird, Elizabeth A.

1995-01-01

Finds that women's preferences for comedy television programs were strongest immediately prior to and during menses when negative affect was also most evident. Finds also that at the midpoint of the menstrual cycle, when positive affect proved the strongest, an elevated interest in suspense drama programs was apparent. (SR)

Experimental infection of pregnant goats with swine fever virus.

PubMed

Shimizu, M; Kumagai, T

1989-07-01

Thirteen pregnant goats were inoculated intravenously with the ALD strain of virulent swine fever (SF) virus on Days 64-84 of gestation. Dams showed transient and mild viremia, and produced high serum neutralizing (SN) antibody after inoculation. Six inoculated dams were reared until parturition occurred and bore six apparently normal, one apparently normal but dead, one mummified and three edematous kids. Neutralizing antibody was demonstrated in the pre-colostral sera obtained from all normal kids, but no SF virus was isolated from any of them. The other seven dams were killed on post-inoculation days (PID) 5-61, and fetuses, placenta and amnion were tested for the virus and SN antibody. All fetuses of five dams examined within PID 40 were positive for SF virus, but negative for SN antibody. SF virus was also isolated from one of three fetuses examined on PID 61. Conversely, the other two fetuses examined on PID 61 were negative for SF virus, but positive for SN antibody. Furthermore, SF virus was isolated from the placenta and amnion of all the dams.

Apparent competition can compromise the safety of highly specific biocontrol agents.

PubMed

Carvalheiro, Luisa G; Buckley, Yvonne M; Ventim, Rita; Fowler, Simon V; Memmott, Jane

2008-07-01

Despite current concern about the safety of biological control of weeds, assessing the indirect impacts of introduced agents is not common practice. Using 17 replicate food webs, we demonstrate that the use of a highly host-plant specific weed biocontrol agent, recently introduced into Australia, is associated with declines of local insect communities. The agent shares natural enemies (predators and parasitoids) with seed herbivore species from native plants, so apparent competition is the most likely cause for these losses. Both species richness and abundance in insect communities (seed herbivores and their parasitoids) were negatively correlated with the abundance of the biocontrol agent. Local losses of up to 11 species (dipteran seed herbivores and parasitoids) took place as the biocontrol agent abundance increased. Ineffective biocontrol agents that remain highly abundant in the community are most likely to have persistent, indirect negative effects. Our findings suggest that more investment is required in pre-release studies on the effectiveness of biocontrol agents, as well as in post-release studies assessing indirect impacts, to avoid or minimize the release of potentially damaging species.

Weak interactions and cooperativity effects on disiloxane: a look at the building block of silicones

NASA Astrophysics Data System (ADS)

Martín-Fernández, Carlos; Montero-Campillo, M. Merced; Alkorta, Ibon; Elguero, José

2018-06-01

The behaviour of disiloxane 1 towards a set of Lewis acids (LA) and Lewis bases (LB) forming complexes through its oxygen and silicon atoms, respectively, was studied at the MP2/aug‧-cc-pVTZ level of theory, exploring a wide variety of non-covalent interactions. Disiloxane is a moderate electron acceptor and a good electron donor, exhibiting in the latter case binding energies up to almost -100 kJ/mol with BeCl2. Cooperativity effects were also analysed by looking at ternary 1:LA:LB complexes. Shorter intermolecular distances than in the corresponding binary complexes and a negative contribution of the three-body term to the binding energy indicate that the non-covalent interactions allowed by disiloxane through its acid and basic centres cooperate between them to reinforce both donor-acceptor pairs. These effects are particularly strong in complexes involving beryllium and triel bonds, but are also relevant for complexes containing hydrogen bonds.

Successful implementation of cooperative handling eliminates the need for restraint in a complex nonhuman primate disease model

PubMed Central

Graham, Melanie L; Rieke, Eric F; Mutch, Lucas A; Zolondek, Elizabeth K; Faig, Aaron W; DuFour, Theresa A; Munson, James W; Kittredge, Jessica A; Schuurman, Henk-Jan

2011-01-01

Introduction Streptozotocin-induced diabetic nonhuman primates are used to study efficacy and safety of innovative immunosuppression after islet transplantation. We implemented a training program for medical management of a chronic disease state. Methods Cooperation with hand feeding and drinking; shifting; and limb presentation were trained utilizing predominately positive but also negative reinforcement in 52 animals compared with 28 macaques subjected to conventional physical and/or chemical restraint. The success of and timing of behavior acquisition was evaluated in a representative subset of 14 animals. Results Over 90% of animals were successful in behavior acquisition. Programmatically this resulted in complete elimination of chair restraint and negligible requirement for sedation. About half of trained animals had no to moderate thymic involution, indicative of a substantial reduction in stress. Conclusion Cooperative handling enhances animal well-being. This contributes to validity of scientific results and eliminates model-induced confounding that can obstruct interpretation of safety and efficacy data. PMID:22150842

A model for the emergence of cooperation, interdependence, and structure in evolving networks.

PubMed

Jain, S; Krishna, S

2001-01-16

Evolution produces complex and structured networks of interacting components in chemical, biological, and social systems. We describe a simple mathematical model for the evolution of an idealized chemical system to study how a network of cooperative molecular species arises and evolves to become more complex and structured. The network is modeled by a directed weighted graph whose positive and negative links represent "catalytic" and "inhibitory" interactions among the molecular species, and which evolves as the least populated species (typically those that go extinct) are replaced by new ones. A small autocatalytic set, appearing by chance, provides the seed for the spontaneous growth of connectivity and cooperation in the graph. A highly structured chemical organization arises inevitably as the autocatalytic set enlarges and percolates through the network in a short analytically determined timescale. This self organization does not require the presence of self-replicating species. The network also exhibits catastrophes over long timescales triggered by the chance elimination of "keystone" species, followed by recoveries.

A model for the emergence of cooperation, interdependence, and structure in evolving networks

NASA Astrophysics Data System (ADS)

Jain, Sanjay; Krishna, Sandeep

2001-01-01

Evolution produces complex and structured networks of interacting components in chemical, biological, and social systems. We describe a simple mathematical model for the evolution of an idealized chemical system to study how a network of cooperative molecular species arises and evolves to become more complex and structured. The network is modeled by a directed weighted graph whose positive and negative links represent "catalytic" and "inhibitory" interactions among the molecular species, and which evolves as the least populated species (typically those that go extinct) are replaced by new ones. A small autocatalytic set, appearing by chance, provides the seed for the spontaneous growth of connectivity and cooperation in the graph. A highly structured chemical organization arises inevitably as the autocatalytic set enlarges and percolates through the network in a short analytically determined timescale. This self organization does not require the presence of self-replicating species. The network also exhibits catastrophes over long timescales triggered by the chance elimination of "keystone" species, followed by recoveries.

[An experience applying the teaching strategies of cooperative learning and creative thinking in a mental-health nursing practicum for undergraduates at a technical college].

PubMed

Huang, Yu-Hsien; Lin, Mei-Feng; Ho, Hsueh-Jen; Chang, Lu-Na; Chen, Shiue

2015-04-01

Lack of knowledge and experience is prevalent in undergraduate students who are taking their clinical practicum for mental-health nursing. This issue negatively affects the learning process. This article shares an experience of implementing a practicum-teaching program. This program was developed by the authors to facilitate the cooperative learning and clinical care competence of students. A series of multidimensional teaching activities was designed by integrating the strategies of peer cooperation and creative thinking to promote group and individual learning. Results indicate that the program successfully encouraged the students to participate more actively in the learning process. Additionally, the students demonstrated increased competence in empathetic caring toward patients, stronger friendship relationships with peers, and improved self-growth. The authors hope this teaching program provides a framework to increase the benefits for students of participating in clinical practicums and provides a teaching reference for clinical instructors.

Kennedy Space Center's NASA/Contractor Team-Centered Total Quality Management Seminar: Results, methods, and lessons learned

NASA Technical Reports Server (NTRS)

Kinlaw, Dennis C.; Eads, Jeannette

1992-01-01

It is apparent to everyone associated with the Nation's aeronautics and space programs that the challenge of continuous improvement can be reasonably addressed only if NASA and its contractors act together in a fully integrated and cooperative manner that transcends the traditional boundaries of proprietary interest. It is, however, one thing to assent to the need for such integration and cooperation; it is quite another thing to undertake the hard tasks of turning such a need into action. Whatever else total quality management is, it is fundamentally a team-centered and team-driven process of continuous improvement. The introduction of total quality management at KSC, therefore, has given the Center a special opportunity to translate the need for closer integration and cooperation among all its organizations into specific initiatives. One such initiative that NASA and its contractors have undertaken at KSC is a NASA/Contractor team-centered Total Quality Management Seminar. It is this seminar which is the subject of this paper. The specific purposes of this paper are to describe the following: Background, development, and evolution of Kennedy Space Center's Total Quality Management Seminar; Special characteristics of the seminar; Content of the seminar; Meaning and utility of a team-centered design for TQM training; Results of the seminar; Use that one KSC contractor, EG&G Florida, Inc. has made of the seminar in its Total Quality Management initiative; and Lessons learned.

Method and apparatus for simulating gravitational forces on a living organism

NASA Technical Reports Server (NTRS)

Thornton, W. E. (Inventor)

1983-01-01

A method and apparatus for simulating gravitational forces on a living organism wherein a series of negative pressures are externally applied to successive length-wise sections of a lower limb of the organism. The pressures decreasing progressively with distance of said limb sections from the heart of the organism. A casing defines a chamber adapted to contain the limb of the organism and is rigidified to resist collapse upon the application of negative pressures to the interior of the chamber. Seals extend inwardly from the casing for effective engagement with the limb of the organism and, in cooperation with the limb, subdivide the chamber into a plurality of compartments each in negative pressure communicating relation with the limb.

Commercializing Higher Learning through the Discourse of Skills in University Co-Operative Education: Tensions and Contradictions

ERIC Educational Resources Information Center

Milley, Peter

2016-01-01

The last 3 decades have witnessed the rise of reforms aimed at conjoining Canadian universities to the economic system. Critics have pointed out how reforms have emphasized economic utility in universities to the detriment of their sociocultural mission, producing negative effects. One curricular innovation that has spread in tandem with reforms…

Gossip as an effective and low-cost form of punishment.

PubMed

Feinberg, Matthew; Cheng, Joey T; Willer, Robb

2012-02-01

The spreading of reputational information about group members through gossip represents a widespread, efficient, and low-cost form of punishment. Research shows that negative arousal states motivate individuals to gossip about the transgressions of group members. By sharing information in this way groups are better able to promote cooperation and maintain social control and order.

Heroic Fantasies: A Cross-Generational Comparison of Two Children's Television Heroes.

ERIC Educational Resources Information Center

Pena, Sally; And Others

1990-01-01

Analyzed the differences between heroes, other characters, and themes from the Roy Rogers television show of the 1950s, and the Brave Starr show of the 1980s. Found the modern hero more prosocial, cooperative, fearful, and self-critical. The modern villain was more hostile, negative, and successful against the hero. Discusses implications for…

Use of Escape and Reward in the Management of Young Children during Dental Treatment.

ERIC Educational Resources Information Center

Allen, Keith D.; Stokes, Trevor F.

1987-01-01

A contingency management procedure using both positive and negative reinforcement was used to strengthen cooperative behavior in five children (ages 3-6) during a series of restorative dental treatment sessions lasting from 15-60 minutes. Baseline levels of disruptive behavior as high as 90 percent were reduced to less than 15 percent. (JW)

Kruppel-like Factor 9 is a Negative Regulator of Ligand-dependent Estrogen Receptor Alpha Signaling in Ishikawa Endometrial Adenocarcinoma Cells

USDA-ARS?s Scientific Manuscript database

Estrogen (E) and progesterone (P), acting through their respective receptors and other nuclear proteins, exhibit opposing activities in target cells. We previously reported that Krüppel-like factor 9 (KLF9) cooperates with progesterone receptor (PR) to facilitate P-dependent gene transcription in ut...

Gene interference regulates aquaporin-4 expression in swollen tissue of rats with cerebral ischemic edema: Correlation with variation in apparent diffusion coefficient.

PubMed

Hu, Hui; Lu, Hong; He, Zhanping; Han, Xiangjun; Chen, Jing; Tu, Rong

2012-07-25

To investigate the effects of mRNA interference on aquaporin-4 expression in swollen tissue of rats with ischemic cerebral edema, and diagnose the significance of diffusion-weighted MRI, we injected 5 μL shRNA- aquaporin-4 (control group) or siRNA- aquaporin-4 solution (1:800) (RNA interference group) into the rat right basal ganglia immediately before occlusion of the middle cerebral artery. At 0.25 hours after occlusion of the middle cerebral artery, diffusion-weighted MRI displayed a high signal; within 2 hours, the relative apparent diffusion coefficient decreased markedly, aquaporin-4 expression increased rapidly, and intracellular edema was obviously aggravated; at 4 and 6 hours, the relative apparent diffusion coefficient slowly returned to control levels, aquaporin-4 expression slightly increased, and angioedema was observed. In the RNA interference group, during 0.25-6 hours after injection of siRNA- aquaporin-4 solution, the relative apparent diffusion coefficient slightly fluctuated and aquaporin-4 expression was upregulated; during 0.5-4 hours, the relative apparent diffusion coefficient was significantly higher, while aquaporin-4 expression was significantly lower when compared with the control group, and intracellular edema was markedly reduced; at 0.25 and 6 hours, the relative apparent diffusion coefficient and aquaporin-4 expression were similar when compared with the control group; obvious angioedema remained at 6 hours. Pearson's correlation test results showed that aquaporin-4 expression was negatively correlated with the apparent diffusion coefficient (r = -0.806, P < 0.01). These findings suggest that upregulated aquaporin-4 expression is likely to be the main molecular mechanism of intracellular edema and may be the molecular basis for decreased relative apparent diffusion coefficient. Aquaporin-4 gene interference can effectively inhibit the upregulation of aquaporin-4 expression during the stage of intracellular edema with time-effectiveness. Moreover, diffusion-weighted MRI can accurately detect intracellular edema.

[Applying competitive polymerase chain reaction to the detection of hepatitis B virus DNA].

PubMed

Wang, Ling; Yang, Peng; Li, Shuang-qing; Xu, Shu-hui; Cao, Gui-qun; Zhang, Fa-qiang; Zhang, Mei-xia; Chen, Qing-ying; Xia, Qing-jie; Liu, Kai; Tang, Fang; Zhang, Yuan-zheng

2004-11-01

To reduce the rate of accidental false negative result in the HBV DNA PCR test on clinical serum samples. A competitive polymerase chain reaction (C-PCR) was used to decrease the false negative ratio. In the C-PCR, a constructed inner control DNA was added for co-amplification with the HBV target DNA. In a 20 microl C-PCR system, about 60 to 200 copies of inner control DNA could give apparent co-amplification signal band after electrophoresis on a 2% agarose gel. Five of 120 samples of clinical serum (4.2%) could not be amplified. C-PCR has the advantage of yielding information on false negative in the HBV DNA PCR assay of clinical serum samples.

Effects of distraction on negative behaviors and salivary α-amylase under mildly stressful medical procedures for brief inpatient children.

PubMed

Tsumura, Hideki; Shimada, Hironori; Morimoto, Hiroshi; Hinuma, Chihiro; Kawano, Yoshiko

2014-08-01

Inconsistent results have been reported on the effects of distraction on negative emotions during medical procedures in infants. These differing results may be attributable to the fact that the effects are apparent under a mildly stressful medical procedure. A total of 17 infants, 18 preschoolers, and 15 school-aged children who were hospitalized were administered, monitoring for vital signs, a mildly stressful medical procedure, by a nurse in a uniform with attractive character designs as a distractor. Consistent with the hypothesis, participating infants showed fewer negative behaviors and lower salivary α-amylase levels when distracted. The results support the efficacy of distraction in infants under a mildly stressful medical procedure. © The Author(s) 2013.

Apparent Minimum Free Energy Requirements for Methanogenic Archaea and Sulfate-Reducing Bacteria in an Anoxic Marine Sediment

NASA Technical Reports Server (NTRS)

Hoehler, Tori M.; Alperin, Marc J.; Albert, Daniel B.; Martens, Christopher S.; DeVincenzi, Don (Technical Monitor)

2000-01-01

Among the most fundamental constraints governing the distribution of microorganisms in the environment is the availability of chemical energy at biologically useful levels. To assess the minimum free energy yield that can support microbial metabolism in situ, we examined the thermodynamics of H2-consuming processes in anoxic sediments from Cape Lookout Bight, NC, USA. Depth distributions of H2 partial pressure, along with a suite of relevant concentration data, were determined in sediment cores collected in November (at 14.5 C) and August (at 27 C) and used to calculate free energy yields for methanogenesis and sulfate reduction. At both times of year, and for both processes, free energy yields gradually decreased (became less negative) with depth before reaching an apparent asymptote. Sulfate reducing bacteria exhibited an asymptote of -19.1 +/- 1.7 kj(mol SO4(2-)(sup -1) while methanogenic archaea were apparently supported by energy yields as small as -10.6 +/- 0.7 kj(mol CH4)(sup -1).

Role of Magnetic Resonance Imaging Targeted Biopsy in Detection of Prostate Cancer Harboring Adverse Pathological Features of Intraductal Carcinoma and Invasive Cribriform Carcinoma.

PubMed

Prendeville, Susan; Gertner, Mark; Maganti, Manjula; Pintilie, Melania; Perlis, Nathan; Toi, Ants; Evans, Andrew J; Finelli, Antonio; van der Kwast, Theodorus H; Ghai, Sangeet

2018-07-01

The aim of this study was to compare biopsy detection of intraductal and cribriform pattern invasive prostate carcinoma in multiparametric magnetic resonance imaging positive and negative regions of the prostate. We queried a prospectively maintained, single institution database to identify patients who underwent multiparametric magnetic resonance imaging/ultrasound fusion targeted biopsy and concurrent systematic sextant biopsy of magnetic resonance imaging negative regions between January 2013 and May 2016. All multiparametric magnetic resonance imaging targets were reviewed retrospectively by 2 readers for the PI-RADS™ (Prostate Imaging-Reporting and Data System), version 2 score, the maximum dimension, the apparent diffusion coefficient parameter and whether positive or negative on dynamic contrast enhancement sequence. Biopsy slides were reviewed by 2 urological pathologists for Gleason score/Grade Group and the presence or absence of an intraductal/cribriform pattern. A total of 154 patients were included in study. Multiparametric magnetic resonance imaging/ultrasound fusion targeted biopsy and systematic sextant biopsy of magnetic resonance imaging negative regions were negative for prostate carcinoma in 51 patients, leaving 103 available for the correlation of multiparametric magnetic resonance imaging and the intraductal/cribriform pattern. Prostate carcinoma was identified by multiparametric magnetic resonance imaging/ultrasound fusion targeted biopsy in 93 cases and by systematic sextant biopsy of magnetic resonance imaging negative regions in 76 (p = 0.008). Intraductal/cribriform positive tumor was detected in 23 cases, including at the multiparametric magnetic resonance imaging/ultrasound fusion targeted biopsy site in 22 and at the systematic sextant biopsy of magnetic resonance imaging negative region site in 3 (p <0.001). The intraductal/cribriform pattern was significantly associated with a PI-RADS score of 5 and a decreasing apparent diffusion coefficient value (p = 0.008 and 0.005, respectively). In 19 of the 23 cases with the intraductal/cribriform pattern prior 12-core standard systematic biopsy was negative in 8 and showed Grade Group 1 disease in 11. Multiparametric magnetic resonance imaging/ultrasound fusion targeted biopsy was associated with significantly increased detection of intraductal/cribriform positive prostate carcinoma compared to systematic sextant biopsy of multiparametric magnetic resonance imaging negative regions. This supports the role of magnetic resonance imaging to enhance the detection of clinically aggressive intraductal/cribriform positive prostate carcinoma. Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

High-concentrate diets based on forages harvested at different maturity stages affect ruminal synthesis of B vitamins in lactating dairy cows.

PubMed

Castagnino, D S; Kammes, K L; Allen, M S; Gervais, R; Chouinard, P Y; Girard, C L

2017-04-01

Effects of plant maturity on apparent ruminal synthesis and post-ruminal supply of B vitamins were evaluated in two feeding trials. Diets containing alfalfa (Trial 1) or orchardgrass (Trial 2) silages harvested either (1) early cut, less mature (EC) or (2) late cut, more mature (LC) as the sole forage were offered to ruminally and duodenally cannulated lactating Holstein cows in crossover design experiments. In Trial 1, conducted with 16 cows (569±43 kg of empty BW (ruminal content removed) and 43.7±8.6 kg/day of 3.5% fat-corrected milk yield; mean±SD) in two 17-day treatment periods, both diets provided ~22% forage NDF and 27% total NDF, and the forage-to-concentrate ratios were 53 : 47 and 42 : 58 for EC and LC, respectively. In Trial 2, conducted with 13 cows (588±55 kg of empty BW and 43.7±7.7 kg/day of 3.5% fat-corrected milk yield; mean±SD) in two 18-day treatment periods, both diets provided ~25% forage NDF and 31% total NDF; the forage-to-concentrate ratios were 58 : 42 and 46 : 54 for EC and LC, respectively. Thiamin, riboflavin, niacin, vitamin B6, folates and vitamin B12 were measured in feed and duodenal content. Apparent ruminal synthesis was calculated as the duodenal flow minus the intake. Diets based on EC alfalfa decreased the amounts of thiamin, niacin and folates reaching the duodenum, whereas diets based on EC orchardgrass increased riboflavin duodenal flow. Daily apparent ruminal synthesis of thiamin, riboflavin, niacin and vitamin B6 were correlated negatively with their intake, suggesting a microbial regulation of their concentration in the rumen. Vitamin B12 apparent ruminal synthesis was correlated negatively with total volatile fatty acids concentration, but positively with ruminal pH and microbial N duodenal flow.

On the spontaneous collective motion of active matter

PubMed Central

Wang, Shenshen; Wolynes, Peter G.

2011-01-01

Spontaneous directed motion, a hallmark of cell biology, is unusual in classical statistical physics. Here we study, using both numerical and analytical methods, organized motion in models of the cytoskeleton in which constituents are driven by energy-consuming motors. Although systems driven by small-step motors are described by an effective temperature and are thus quiescent, at higher order in step size, both homogeneous and inhomogeneous, flowing and oscillating behavior emerges. Motors that respond with a negative susceptibility to imposed forces lead to an apparent negative-temperature system in which beautiful structures form resembling the asters seen in cell division. PMID:21876141

On the spontaneous collective motion of active matter.

PubMed

Wang, Shenshen; Wolynes, Peter G

2011-09-13

Spontaneous directed motion, a hallmark of cell biology, is unusual in classical statistical physics. Here we study, using both numerical and analytical methods, organized motion in models of the cytoskeleton in which constituents are driven by energy-consuming motors. Although systems driven by small-step motors are described by an effective temperature and are thus quiescent, at higher order in step size, both homogeneous and inhomogeneous, flowing and oscillating behavior emerges. Motors that respond with a negative susceptibility to imposed forces lead to an apparent negative-temperature system in which beautiful structures form resembling the asters seen in cell division.

Applying the Yule-Nielsen equation with negative n.

PubMed

Lewandowski, Achim; Ludl, Marcus; Byrne, Gerald; Dorffner, Georg

2006-08-01

The theory of halftone printing has attracted the attention of both industry and scientists for decades. The Yule-Nielsen equation has been used for color prediction for more than fifty years now, but apparently the tuning parameter n has been taken to be only larger than or equal to one. Our paper shows that the extension to the whole real axis is well defined in a mathematical sense. We fitted models to data from the ceramics tile printing sector (Rotocolor and Kerajet printing techniques) and found that using a negative n in almost all considered cases resulted in a better fit.

A nomogram for predicting complications in patients with solid tumours and seemingly stable febrile neutropenia.

PubMed

Fonseca, Paula Jiménez; Carmona-Bayonas, Alberto; García, Ignacio Matos; Marcos, Rosana; Castañón, Eduardo; Antonio, Maite; Font, Carme; Biosca, Mercè; Blasco, Ana; Lozano, Rebeca; Ramchandani, Avinash; Beato, Carmen; de Castro, Eva Martínez; Espinosa, Javier; Martínez-García, Jerónimo; Ghanem, Ismael; Cubero, Jorge Hernando; Manrique, Isabel Aragón; Navalón, Francisco García; Sevillano, Elena; Manzano, Aránzazu; Virizuela, Juan; Garrido, Marcelo; Mondéjar, Rebeca; Arcusa, María Ángeles; Bonilla, Yaiza; Pérez, Quionia; Gallardo, Elena; Del Carmen Soriano, Maria; Cardona, Mercè; Lasheras, Fernando Sánchez; Cruz, Juan Jesús; Ayala, Francisco

2016-05-24

We sought to develop and externally validate a nomogram and web-based calculator to individually predict the development of serious complications in seemingly stable adult patients with solid tumours and episodes of febrile neutropenia (FN). The data from the FINITE study (n=1133) and University of Salamanca Hospital (USH) FN registry (n=296) were used to develop and validate this tool. The main eligibility criterion was the presence of apparent clinical stability, defined as events without acute organ dysfunction, abnormal vital signs, or major infections. Discriminatory ability was measured as the concordance index and stratification into risk groups. The rate of infection-related complications in the FINITE and USH series was 13.4% and 18.6%, respectively. The nomogram used the following covariates: Eastern Cooperative Group (ECOG) Performance Status ⩾2, chronic obstructive pulmonary disease, chronic cardiovascular disease, mucositis of grade ⩾2 (National Cancer Institute Common Toxicity Criteria), monocytes <200/mm(3), and stress-induced hyperglycaemia. The nomogram predictions appeared to be well calibrated in both data sets (Hosmer-Lemeshow test, P>0.1). The concordance index was 0.855 and 0.831 in each series. Risk group stratification revealed a significant distinction in the proportion of complications. With a ⩾116-point cutoff, the nomogram yielded the following prognostic indices in the USH registry validation series: 66% sensitivity, 83% specificity, 3.88 positive likelihood ratio, 48% positive predictive value, and 91% negative predictive value. We have developed and externally validated a nomogram and web calculator to predict serious complications that can potentially impact decision-making in patients with seemingly stable FN.

Effects of Israeli Press Restrictions on Coverage of the Palestinian Uprising and on U.S. Public Opinion.

ERIC Educational Resources Information Center

Griffin, Jeffrey L.

Comparing United States television news coverage of the Palestinian uprising in the Israeli-occupied territories before and after press restrictions were introduced in March 1988, a study examined whether Israel's press clampdown (restricting particularly the activities of camera crews, and apparently begun in response to negative foreign opinion…

Housing Patterns in Relation to Educational Achievement. Project SIMU School: Santa Clara County Component.

ERIC Educational Resources Information Center

Baker, William P.; Hoffmann, Glenn W.

This paper focuses attention on the critical importance of zoning and housing to education. It covers the causes of undersirable housing patterns, the apparent effects of these patterns on educational achievement, and possibilities for positive action to reverse the negative effects. Although examples are drawn from Santa Clara County, the thesis…

"What Would You Do, What If It's You?" Strategies to Deal with a Bully

ERIC Educational Resources Information Center

Morrison, Charles T.

2009-01-01

Bullying can be defined as a repeated negative interpersonal relationship characterized by an imbalance of power targeted at a person that is perceived to be weaker or more vulnerable, without apparent provocation. When bullying is not addressed, the effects are substantial. Bullying affects the targets (anxious, afraid, and failure to concentrate…

Structure, High Affinity, and Negative Cooperativity of the Escherichia coli Holo-(Acyl Carrier Protein):Holo-(Acyl Carrier Protein) Synthase Complex

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

Marcella, Aaron M.; Culbertson, Sannie J.; Shogren-Knaak, Michael A.

The Escherichia coli holo-(acyl carrier protein) synthase (ACPS) catalyzes the coenzyme A-dependent activation of apo-ACPP to generate holo-(acyl carrier protein) (holo-ACPP) in an early step of fatty acid biosynthesis. E. coli ACPS is sufficiently different from the human fatty acid synthase to justify the development of novel ACPS-targeting antibiotics. Models of E. coli ACPS in unliganded and holo-ACPP-bound forms solved by X-ray crystallography to 2.05 and 4.10 Å, respectively, revealed that ACPS bound three product holo-ACPP molecules to form a 3:3 hexamer. Solution NMR spectroscopy experiments validated the ACPS binding interface on holo-ACPP using chemical shift perturbations and by determiningmore » the relative orientation of holo-ACPP to ACPS by fitting residual dipolar couplings. The binding interface is organized to arrange contacts between positively charged ACPS residues and the holo-ACPP phosphopantetheine moiety, indicating product contains more stabilizing interactions than expected in the enzyme:substrate complex. Indeed, holo-ACPP bound the enzyme with greater affinity than the substrate, apo-ACPP, and with negative cooperativity. The first equivalent of holo-ACPP bound with a KD = 62 ± 13 nM, followed by the binding of two more equivalents of holo-ACPP with KD = 1.2 ± 0.2 μM. Cooperativity was not observed for apo-ACPP which bound with KD = 2.4 ± 0.1 μM. Strong product binding and high levels of holo-ACPP in the cell identify a potential regulatory role of ACPS in fatty acid biosynthesis.« less

Phosphorus utilization response of pigs and broiler chickens to diets supplemented with antimicrobials and phytase.

PubMed

McCormick, Katherine; Walk, Carrie L; Wyatt, Craig L; Adeola, Olayiwola

2017-03-01

Three experiments were conducted to evaluate the phosphorus (P) utilization responses of pigs and broiler chickens to dietary supplementation with antimicrobials and phytase and to determine if P digestibility response to phytase is affected by supplementation with antimicrobials. Experiment 1 used 4 diets (a basal negative control formulated to contain 0.41% total P and 0.71% calcium [Ca] without added antimicrobials, basal negative control with added carbadox, basal negative control with added tylosin, or basal negative control with added virginiamycin) and six 18-kg barrows in individual metabolism crates per diet. There was no effect of antimicrobials on P and Ca digestibility or retention. Carbadox supplementation increased ( P  < 0.05) digestibility and retention of gross energy (GE) and supplementation with tylosin increased ( P  < 0.05) N retention relative to the basal negative control diet. Experiment 2 used eight 19-kg barrows in individual metabolism crates per treatment and 9 dietary treatments arranged in a 3 × 3 factorial of antimicrobials (none, tylosin, or virginiamycin) and phytase (0, 500, or 1,500 FTU/kg). Phytase addition to the diets linearly increased ( P  < 0.05) apparent total tract digestibility or retention of P, Ca, nitrogen (N) and GE. Supplementation with antimicrobials did not affect apparent total tract digestibility or retention of P, Ca, N or GE. There were linear effects ( P  < 0.01) of phytase on Ca utilization in diets that were not supplemented with antimicrobials but only tendencies ( P  < 0.10) in diets supplemented with tylosin or virginiamycin. Phytase linearly improved ( P  < 0.05) N utilization in diets supplemented with tylosin or virginiamycin but not in diets without added antimicrobials. Experiment 3 was a broiler chicken experiment with the same experimental design as Exp. 2 but feeding 8 birds per cage and 10 replicate cages per diet. Antimicrobial supplementation improved ( P  < 0.05) feed efficiency and adding tylosin improved ( P  < 0.05) tibia ash but did not affect nutrient utilization. Dietary phytase improved ( P  < 0.01) growth performance, tibia ash and apparent ileal digestibility and retention of P regardless of antimicrobial supplementation. Overall, phytase supplementation improved growth performance and nutrient digestibility and retention, regardless of supplementation of diets with antimicrobials. Supplementation of diets with antimicrobials did not affect P digestibility or retention because of a lack of interaction between antimicrobials and phytase, there was no evidence that P digestibility response to phytase is affected by supplementation with antimicrobials.

Resource conflict and cooperation between human host and gut microbiota: implications for nutrition and health.

PubMed

Wasielewski, Helen; Alcock, Joe; Aktipis, Athena

2016-05-01

Diet has been known to play an important role in human health since at least the time period of the ancient Greek physician Hippocrates. In the last decade, research has revealed that microorganisms inhabiting the digestive tract, known as the gut microbiota, are critical factors in human health. This paper draws on concepts of cooperation and conflict from ecology and evolutionary biology to make predictions about host-microbiota interactions involving nutrients. To optimally extract energy from some resources (e.g., fiber), hosts require cooperation from microbes. Other nutrients can be utilized by both hosts and microbes (e.g., simple sugars, iron) in their ingested form, which may lead to greater conflict over these resources. This framework predicts that some negative health effects of foods are driven by the direct effects of these foods on human physiology and by indirect effects resulting from microbiome-host competition and conflict (e.g., increased invasiveness and inflammation). Similarly, beneficial effects of some foods on host health may be enhanced by resource sharing and other cooperative behaviors between host and microbes that may downregulate inflammation and virulence. Given that some foods cultivate cooperation between hosts and microbes while others agitate conflict, host-microbe interactions may be novel targets for interventions aimed at improving nutrition and human health. © 2016 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals, Inc. on behalf of New York Academy of Sciences.

c-Jun and Hypoxia-Inducible Factor 1 Functionally Cooperate in Hypoxia-Induced Gene Transcription

PubMed Central

Alfranca, Arántzazu; Gutiérrez, M. Dolores; Vara, Alicia; Aragonés, Julián; Vidal, Felipe; Landázuri, Manuel O.

2002-01-01

Under low-oxygen conditions, cells develop an adaptive program that leads to the induction of several genes, which are transcriptionally regulated by hypoxia-inducible factor 1 (HIF-1). On the other hand, there are other factors which modulate the HIF-1-mediated induction of some genes by binding to cis-acting motifs present in their promoters. Here, we show that c-Jun functionally cooperates with HIF-1 transcriptional activity in different cell types. Interestingly, a dominant-negative mutant of c-Jun which lacks its transactivation domain partially inhibits HIF-1-mediated transcription. This cooperative effect is not due to an increase in the nuclear amount of the HIF-1α subunit, nor does it require direct binding of c-Jun to DNA. c-Jun and HIF-1α are able to associate in vivo but not in vitro, suggesting that this interaction involves the participation of additional proteins and/or a posttranslational modification of these factors. In this context, hypoxia induces phosphorylation of c-Jun at Ser63 in endothelial cells. This process is involved in its cooperative effect, since specific blockade of the JNK pathway and mutation of c-Jun at Ser63 and Ser73 impair its functional cooperation with HIF-1. The functional interplay between c-Jun and HIF-1 provides a novel insight into the regulation of some genes, such as the one for VEGF, which is a key regulator of tumor angiogenesis. PMID:11739718

Harvest and group effects on pup survival in a cooperative breeder

USGS Publications Warehouse

Ausband, David E.; Mitchell, Michael S.; Stansbury, Carisa R.; Stenglein, Jennifer L.; Waits, Lisette P.

2017-01-01

Recruitment in cooperative breeders can be negatively affected by changes in group size and composition. The majority of cooperative breeding studies have not evaluated human harvest; therefore, the effects of recurring annual harvest and group characteristics on survival of young are poorly understood. We evaluated how harvest and groups affect pup survival using genetic sampling and pedigrees for grey wolves in North America. We hypothesized that harvest reduces pup survival because of (i) reduced group size, (ii) increased breeder turnover and/or (iii) reduced number of female helpers. Alternatively, harvest may increase pup survival possibly due to increased per capita food availability or it could be compensatory with other forms of mortality. Harvest appeared to be additive because it reduced both pup survival and group size. In addition to harvest, turnover of breeding males and the presence of older, non-breeding males also reduced pup survival. Large groups and breeder stability increased pup survival when there was harvest, however. Inferences about the effect of harvest on recruitment require knowledge of harvest rate of young as well as the indirect effects associated with changes in group size and composition, as we show. The number of young harvested is a poor measure of the effect of harvest on recruitment in cooperative breeders.

Default distrust? An fMRI investigation of the neural development of trust and cooperation

PubMed Central

Gromann, Paula M.; Giampietro, Vincent; Shergill, Sukhi S.; Krabbendam, Lydia

2014-01-01

The tendency to trust and to cooperate increases from adolescence to adulthood. This social development has been associated with improved mentalizing and age-related changes in brain function. Thus far, there is limited imaging data investigating these associations. We used two trust games with a trustworthy and an unfair partner to explore the brain mechanisms underlying trust and cooperation in subjects ranging from adolescence to mid-adulthood. Increasing age was associated with higher trust at the onset of social interactions, increased levels of trust during interactions with a trustworthy partner and a stronger decline in trust during interactions with an unfair partner. Our findings demonstrate a behavioural shift towards higher trust and an age-related increase in the sensitivity to others’ negative social signals. Increased brain activation in mentalizing regions, i.e. temporo-parietal junction, posterior cingulate and precuneus, supported the behavioural change. Additionally, age was associated with reduced activation in the reward-related orbitofrontal cortex and caudate nucleus during interactions with a trustworthy partner, possibly reflecting stronger expectations of trustworthiness. During unfair interactions, age-related increases in anterior cingulate activation, an area implicated in conflict monitoring, may mirror the necessity to inhibit pro-social tendencies in the face of the partner’s actual levels of cooperation. PMID:23202661

Report on Region III's asbestos hotline. Technical report

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

Lubick, L.

1989-01-01

The report is part of the National Network for Environmental Management Studies under the auspices of the Office of Cooperative Environmental Management of the U.S. Environmental Protection Agency. The research project studies the effectiveness of an asbestos hotline that was created by Reg. III in June, 1989 through the cooperative efforts of the Air Enforcement Branch and Toxics and Pesticides Branch in Region III for use in the Annapolis, MD area. The hotline enables public officials to act upon confidential tips provided by citizens who are aware of potential asbestos violations. The major thrust of the NNEMS project focuses onmore » outreach activities-making the public aware of asbestos problems and of the Annapolis hotline as a tool to address their concerns. Diverse groups were targeted through press, radio, Congress and the public school system explaining the role citizens play in the control of asbestos. Subsequent citizen use of the hotline cited violations in public offices and manufacturing buildings, but did not produce reports of violations in school facilities. Apparently, school fliers failed to reach their target audience. Preliminary analysis indicates that the most effective method to publicize the hotline is through public service announcements on radio and in newspapers.« less

Negative frequencies in wave propagation: A microscopic model

NASA Astrophysics Data System (ADS)

Horsley, S. A. R.; Bugler-Lamb, S.

2016-06-01

A change in the sign of the frequency of a wave between two inertial reference frames corresponds to a reversal of the phase velocity. Yet from the point of view of the relation E =ℏ ω , a positive quantum of energy apparently becomes a negative-energy one. This is physically distinct from a change in the sign of the wave vector and can be associated with various effects such as Cherenkov radiation, quantum friction, and the Hawking effect. In this work we provide a more detailed understanding of these negative-frequency modes based on a simple microscopic model of a dielectric medium as a lattice of scatterers. We calculate the classical and quantum mechanical radiation damping of an oscillator moving through such a lattice and find that the modes where the frequency has changed sign contribute negatively. In terms of the lattice of scatterers we find that this negative radiation damping arises due to the phase of the periodic force experienced by the oscillator due to the relative motion of the lattice.

Positive And Negative Feedback Loops Coupled By Common Transcription Activator And Repressor

NASA Astrophysics Data System (ADS)

Sielewiesiuk, Jan; Łopaciuk, Agata

2015-03-01

Dynamical systems consisting of two interlocked loops with negative and positive feedback have been studied using the linear analysis of stability and numerical solutions. Conditions for saddle-node bifurcation were formulated in a general form. Conditions for Hopf bifurcations were found in a few symmetrical cases. Auto-oscillations, when they exist, are generated by the negative feedback repressive loop. This loop determines the frequency and amplitude of oscillations. The positive feedback loop of activation slightly modifies the oscillations. Oscillations are possible when the difference between Hilll's coefficients of the repression and activation is sufficiently high. The highly cooperative activation loop with a fast turnover slows down or even makes the oscillations impossible. The system under consideration can constitute a component of epigenetic or enzymatic regulation network.

A flight investigation of blade section aerodynamics for a helicopter main rotor having NLR-1T airfoil sections

NASA Technical Reports Server (NTRS)

Morris, C. E. K., Jr.; Stevens, D. D.; Tomaine, R. L.

1980-01-01

A flight investigation was conducted using a teetering-rotor AH-1G helicopter to obtain data on the aerodynamic behavior of main-rotor blades with the NLR-1T blade section. The data system recorded blade-section aerodynamic pressures at 90 percent rotor radius as well as vehicle flight state, performance, and loads. The test envelope included hover, forward flight, and collective-fixed maneuvers. Data were obtained on apparent blade-vortex interactions, negative lift on the advancing blade in high-speed flight and wake interactions in hover. In many cases, good agreement was achieved between chordwise pressure distributions predicted by airfoil theory and flight data with no apparent indications of blade-vortex interactions.

Group Work at University: Significance of Personal Goals in the Regulation Strategies of Students with Positive and Negative Appraisals

ERIC Educational Resources Information Center

Volet, Simone; Mansfield, Caroline

2006-01-01

This paper examines the mediating role of students' goals in group work at university. Research on cooperative and collaborative learning has provided empirical support for the cognitive, motivational and social benefits of group work but the antecedents of motivation and ongoing management of emerging motivational and socio-emotional issues have…

Phase diagram of electron systems near the superconductor-insulator transition.

PubMed

Pokrovsky, V L; Falco, G M; Nattermann, T

2010-12-31

The zero temperature phase diagram of Cooper pairs exposed to disorder and a magnetic field is determined theoretically from a variational approach. Four distinct phases are found: a Bose and a Fermi insulating, a metallic, and a superconducting phase, respectively. The results explain the giant negative magnetoresistance found experimentally in In-O, TiN, Be and high-T(c) materials.

Cloning and functional analysis of 5'-upstream region of the Pokemon gene.

PubMed

Yang, Yutao; Zhou, Xiaowei; Zhu, Xudong; Zhang, Chuanfu; Yang, Zhixin; Xu, Long; Huang, Peitang

2008-04-01

Pokemon, the POK erythroid myeloid ontogenic factor, not only regulates the expression of many genes, but also plays an important role in cell tumorigenesis. To investigate the molecular mechanism regulating expression of the Pokemon gene in humans, its 5'-upstream region was cloned and analyzed. Transient analysis revealed that the Pokemon promoter is constitutive. Deletion analysis and a DNA decoy assay indicated that the NEG-U and NEG-D elements were involved in negative regulation of the Pokemon promoter, whereas the POS-D element was mainly responsible for its strong activity. Electrophoretic mobility shift assays suggested that the NEG-U, NEG-D and POS-D elements were specifically bound by the nuclear extract from A549 cells in vitro. Mutation analysis demonstrated that cooperation of the NEG-U and NEG-D elements led to negative regulation of the Pokemon promoter. Moreover, the NEG-U and NEG-D elements needed to be an appropriate distance apart in the Pokemon promoter in order to cooperate. Taken together, our results elucidate the mechanism underlying the regulation of Pokemon gene transcription, and also define a novel regulatory sequence that may be used to decrease expression of the Pokemon gene in cancer gene therapy.

Electrostatically driven immobilization of peptides onto (Maleic anhydride-alt-methyl vinyl ether) copolymers in aqueous media.

PubMed

Ladavière, C; Lorenzo, C; Elaïssari, A; Mandrand, B; Delair, T

2000-01-01

The covalent immobilization of a model peptide onto the MAMVE copolymer, via the formation of amide bonds, occurred in moderate yields in aqueous conditions. The improvement of the grafting reaction was achieved by adding at the amino terminus of the model peptide a sequence (tag) of three positively charged amino acids, lysine or arginine, and by taking profit of electrostatic attractive interactions between the negatively charged copolymer and the tagged peptides. The arginine tag was more efficient than the lysine tag for enhancing the immobilization reaction, proving that the effect was due to an electrostic driving force. On the basis of these results, a tentative mechanism is discussed, and Scatchard plots pointed out two regimes of binding. With the first, at low polymer load (up to 50% of saturation for a lysine tag and 60-70% for an arginine tag), the binding occurred with a positive cooperative effect, the already bound peptide participating to the binding of others. A second one for higher coverages, for which the binding occurred with a negative cooperativity, and saturation was reached in the presence of a large excess of peptide.

Carbene-aerogen bonds: an ab initio study

NASA Astrophysics Data System (ADS)

Esrafili, Mehdi D.; Sabouri, Ayda

2017-04-01

Through the use of ab initio calculations, the possibility of formation of σ-hole interaction between ZO3 (Z = Ar, Kr and Xe) and carbene species is investigated. Since singlet carbenes show a negative electrostatic potential on their divalent carbon atom, they can favourably interact with the positive electrostatic potential generated by the σ-hole of Z atom of ZO3. The characteristic of this interaction, termed as 'carbene-aerogen' bond, is analysed in terms of geometric, interaction energies and electronic features. The energy decomposition analysis indicates that for all complexes analysed here, the electrostatic energy is more negative than the polarisation or dispersion energy term. According to the electron density analysis, some partial covalent character can be ascribed to XeṡṡṡC interactions. In addition, the carbene-aerogen bond exhibits cooperative effects with the HṡṡṡO hydrogen-bonding interaction in ternary complexes where both interactions coexist. For a given carbene, the amount of these cooperative effects increases with the size of the Z atom. The results obtained in this work may be helpful for the extension and future application of σ-hole intermolecular interactions as well as coordination chemistry.

Bias effects in the possible/impossible object decision test with matching objects.

PubMed

Soldan, Anja; Hilton, H John; Stern, Yaakov

2009-03-01

In the possible/impossible object decision test, priming has consistently been found for structurally possible, but not impossible, objects, leading Schacter, Cooper, and Delaney (1990) to suggest that priming relies on a system that represents the global 3-D structure of objects. Using a modified design with matching objects to control for the influence of episodic memory, Ratcliff and McKoon (1995) and Williams and Tarr (1997) found negative priming for impossible objects (i.e., lower performance for old than for new items). Both teams argued that priming derives from (1) episodic memory for object features and (2) bias to respond "possible" to encoded objects or their possible parts. The present study applied the matched-objects design to the original Schacter and Cooper stimuli-same possible objects and matching impossible figures-with minimal procedural variation. The data from Experiment 1 only partially supported the bias models and suggested that priming was mediated by both local and global structural descriptions. Experiment 2 showed that negative priming for impossible objects derived from the structural properties of these objects, not from the influence of episodic memory on task performance. Supplemental materials for this study may be downloaded from mc.psychonomic-journals.org/content/supplemental.

Social value orientation modulates the FRN and P300 in the chicken game.

PubMed

Wang, Yiwen; Kuhlman, D Michael; Roberts, Kathryn; Yuan, Bo; Zhang, Zhen; Zhang, Wei; Simons, Robert F

2017-07-01

Social dilemmas pervade daily life, business, and politics. The manners in which these dilemmas are resolved depend in part on the personal characteristics of those involved. One such characteristic is Social Value Orientation (SVO), a trait-like predisposition to maximize cooperative (Pro-Social) or non-cooperative (Pro-Self) outcomes in social relationships. The present study investigated the role of SVO in modulating neural responses to outcomes in a type of social dilemma known as the Chicken Game. The Chicken Game models real-world situations involving two parties independently making a decision between cooperation and aggression. The EEG of Pro-Socials and Pro-Selfs was recorded while playing Chicken with a computer Opponent. Two ERP components were extracted: Feedback-Related Negativity (FRN) and the P300. Despite no behavioral differences in decision (i.e., cooperation, aggression), FRN results indicate that Pro-Socials experienced unreciprocated cooperation as the least desired outcome. Further, P300 results show a main effect for the Opponent's choice, such that the Opponent's cooperation was more salient than aggression. Additionally, an interaction between the Participant's and Opponent's choice showed that the effect for the Opponent's choice only occurred when the Participant chose cooperation. None of the results for P300 were moderated by SVO. For both ERP components, Pro-Selfs showed no differential responding to Chicken outcomes. In addition, FRN magnitude on trial n predicted choice on trial n+1 for Pro-Socials, but not for Pro-Selfs. P300 magnitude on trial n showed no relationship to choice on trial n+1. Results indicate that individual differences in SVO modulate FRN responses to Chicken outcomes, and that these neural reactions may have utility in predicting subsequent behaviors. For P300, there is no evidence of SVO modulation. Our general pattern of FRN responsiveness in Pro-Socials, but not in Pro-Selfs, is related to similar findings in fMRI and EEG research. Copyright © 2017 Elsevier B.V. All rights reserved.

Involvement of the Ventrolateral Prefrontal Cortex in Learning Others' Bad Reputations and Indelible Distrust.

PubMed

Suzuki, Atsunobu; Ito, Yuichi; Kiyama, Sachiko; Kunimi, Mitsunobu; Ohira, Hideki; Kawaguchi, Jun; Tanabe, Hiroki C; Nakai, Toshiharu

2016-01-01

A bad reputation can persistently affect judgments of an individual even when it turns out to be invalid and ought to be disregarded. Such indelible distrust may reflect that the negative evaluation elicited by a bad reputation transfers to a person. Consequently, the person him/herself may come to activate this negative evaluation irrespective of the accuracy of the reputation. If this theoretical model is correct, an evaluation-related brain region will be activated when witnessing a person whose bad reputation one has learned about, regardless of whether the reputation is deemed valid or not. Here, we tested this neural hypothesis with functional magnetic resonance imaging (fMRI). Participants memorized faces paired with either a good or a bad reputation. Next, they viewed the faces alone and inferred whether each person was likely to cooperate, first while retrieving the reputations, and then while trying to disregard them as false. A region of the left ventrolateral prefrontal cortex (vlPFC), which may be involved in negative evaluation, was activated by faces previously paired with bad reputations, irrespective of whether participants attempted to retrieve or disregard these reputations. Furthermore, participants showing greater activity of the left ventrolateral prefrontal region in response to the faces with bad reputations were more likely to infer that these individuals would not cooperate. Thus, once associated with a bad reputation, a person may elicit evaluation-related brain responses on their own, thereby evoking distrust independently of their reputation.

The stable carbon isotope composition of methane produced and emitted from northern peatlands

NASA Astrophysics Data System (ADS)

Hornibrook, Edward R. C.

Stable carbon isotope values, pore water concentration, and flux data for methane (CH4) were compiled for 26 peatlands situated in the northern hemisphere to explore relationships between trophic status and CH4 cycling. Methane produced in ombrotrophic bogs has δ13C values that are significantly more negative than CH4 formed in fens apparently because of poor dissociation of acetic acid or an absence of methanogenic archaea capable of metabolizing acetic acid under low pH conditions. The δ 13C values of CH4 in pore water of ombrotrophic and minerotrophic peatlands exhibit the opposite trend: δ13C(CH4) values become more positive with depth in rain-fed bogs and more negative with depth in fens. The key zone for methanogenesis occurs at shallow depths in both types of peatland and consequently, δ13C values of CH4 emitted from ombrotrophic bogs (-74.9 ± 9.8‰ n = 42) are more negative than from fens (-64.8 ± 4.0‰ n = 38). An abundance of graminoids in fens contributes to more positive δ13C(CH4) values in pore water through (1) release of root exudates which promotes aceticlastic methanogenesis, (2) rhizosphere oxidization of CH4 causing localized enrichment of 13CH4, and (3) preferential export of 12CH4 through aerenchyma, which also enriches pore water in 13CH4. Emissions from blanket bogs and raised bogs should be attributed more negative δ13C(CH4) values relative to fens in isotope-weighted mass balance budgets. Further study is needed of bogs that have an apparently low nutrient status but exhibit a pore water distribution of δ13C(CH4) values similar to fens.

Apparent chlorofluorocarbon age of ground water of the shallow aquifer system, Naval Weapons Station Yorktown, Yorktown, Virginia

USGS Publications Warehouse

Nelms, David L.; Harlow, George E.; Brockman, Allen R.

2001-01-01

Apparent ages of ground water are useful in the analysis of various components of flow systems, and results of this analysis can be incorporated into investigations of potential pathways of contaminant transport. This report presents the results of a study in 1997 by the U.S. Geological Survey (USGS), in cooperation with the Naval Weapons Station Yorktown, Base Civil Engineer, Environmental Directorate, to describe the apparent age of ground water of the shallow aquifer system at the Station. Chlorofluorocarbons (CFCs), tritium (3H), dissolved gases, stable isotopes, and water-quality field properties were measured in samples from 14 wells and 16 springs on the Station in March 1997.Nitrogen-argon recharge temperatures range from 5.9°C to 17.3°C with a median temperature of 10.9°C, which indicates that ground-water recharge predominantly occurs in the cold months of the year. Concentrations of excess air vary depending upon geohydrologic setting (recharge and discharge areas). Apparent ground-water ages using a CFC-based dating technique range from 1 to 48 years with a median age of 10 years. The oldest apparent CFC ages occur in the upper parts of the Yorktown-Eastover aquifer, whereas the youngest apparent ages occur in the Columbia aquifer and the upper parts of the discharge area setting, especially springs. The vertical distribution of apparent CFC ages indicates that groundwater movement between aquifers is somewhat retarded by the leaky confining units, but the elapsed time is relatively short (generally less than 35 years), as evidenced by the presence of CFCs at depth. The identification of binary mixtures by CFC-based dating indicates that convergence of flow lines occurs not only at the actual point of discharge, but also in the subsurface.The CFC-based recharge dates are consistent with expected 3H concentrations measured in the water samples from the Station. The concentration of 3H in ground water ranges from below the USGS laboratory minimum reporting limit of 0.3 to 15.9 tritium units (TU) with a median value of 10.8 TU. Water-quality field properties are highly variable for ground water with apparent CFC ages less than 15 years because of geochemical processes within local flow systems. Ground water with apparent CFC ages greater than 15 years represents more stable conditions in subregional flow systems.The range of apparent CFC ages is slightly greater than the ranges in time of travel of ground water calculated for shallow wells (less than 60- feet deep) from flow-path analysis. Calculated travel times to springs can be up to two orders of magnitude greater than the CFC-based apparent ages. Reasonable assumptions of values for hydraulic parameters can result in substantial overestimates for time of travel to springs.Recharge rates computed from apparent CFC ages range from 0.29 to 0.89 feet per year (ft/ yr) with an average value of 0.54 ft/yr. The analysis of apparent CFC ages in conjunction with geohydrologic data indicates that young water (less than 50 years) is present at depth (nearly 120 feet) and that both local and subregional flow systems occur in the shallow aquifer system at the Station. The addition of the dimension of time to the three-dimensional framework of Brockman and others (1997) will benefit current (2001) and future remediation activities by providing estimates of advective transport rates and how these rates vary depending upon geohydrologic setting and position within the ground-water-flow system. Estimated ground-water apparent ages and recharge rates can be used as calibration criteria in simulations of ground-water flow on the Station to refine and constrain future ground-water-flow models of the shallow aquifer system.

Effect of reactivity loss on apparent reaction order of burning char particles

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

Murphy, Jeffrey J.; Shaddix, Christopher R.

Considerable debate still exists in the char combustion community over the expected and observed reaction orders of carbon reacting with oxygen. In particular, very low values of the reaction order (approaching zero) are commonly observed in char combustion experiments. These observations appear to conflict with porous catalyst theory as first expressed by Thiele, which suggests that the apparent reaction order must be greater than 0.5. In this work, we propose that this conflict may be resolved by considering the decrease in char reactivity with burnout due to ash effects, thermal annealing, or other phenomena. Specifically, the influence of ash dilutionmore » of the available surface area on the apparent reaction order is explored. Equations describing the ash dilution effect are combined with a model for particle burnout based on single-film nth-order Arrhenius char combustion and yield an analytical expression for the effective reaction order. When this expression is applied for experimental conditions reflecting combustion of individual pulverized coal particles in an entrained flow reactor, the apparent reaction order is shown to be lower than the inherent char matrix reaction order, even for negligible extents of char conversion. As char conversion proceeds and approaches completion, the apparent reaction order drops precipitously past zero to negative values. Conversely, the inclusion of the ash dilution model has little effect on the char conversion profile or char particle temperature until significant burnout has occurred. Taken together, these results suggest that the common experimental observation of low apparent reaction orders during char combustion is a consequence of the lack of explicit modeling of the decrease in char reactivity with burnout. (author)« less

Higher social intelligence can impair source memory.

PubMed

Barber, Sarah J; Franklin, Nancy; Naka, Makiko; Yoshimura, Hiroki

2010-03-01

Source monitoring is made difficult when the similarity between candidate sources increases. The current work examines how individual differences in social intelligence and perspective-taking abilities serve to increase source similarity and thus negatively impact source memory. Strangers first engaged in a cooperative storytelling task. On each trial, a single word was shown to both participants, but only 1 participant was designated to add a story sentence, using this assigned word. As predicted, social intelligence negatively predicted performance in a subsequent source-monitoring task. In a 2nd study, preventing participants from being able to anticipate their partner's next contribution to the story eliminated the effect.

Stereotypes of Cantonese English, Apparent Native/Non-Native Status, and Their Effect on Non-Native English Speakers' Perception

ERIC Educational Resources Information Center

Hu, Guiling; Lindemann, Stephanie

2009-01-01

This study examined the effect of information about native/non-native speaker status on non-native listeners' perception of English words with word-final stops. A survey study conducted with 38 Chinese learners of English in Guangzhou, China examined their stereotypes about Cantonese English. They described it negatively and named features…

Nonconscious Influence of Masked Stimuli on Response Selection Is Limited to Concrete Stimulus-Response Associations

ERIC Educational Resources Information Center

Klapp, Stuart T.; Haas, Brian W.

2005-01-01

A pattern-masked arrow negatively biased the "free choice" between 2 manual responses or between 2 vocal responses. This apparently nonconscious influence occurred only when the free-choice trials were intermixed randomly with other trials that terminated in fully visible arrows, which directed a response of the same modality (manual vs. vocal) as…

Altered perception of apparent motion in schizophrenia spectrum disorder.

PubMed

Tschacher, Wolfgang; Dubouloz, Priscilla; Meier, Rahel; Junghan, Uli

2008-06-30

Apparent motion (AM), the Gestalt perception of motion in the absence of physical motion, was used to study perceptual organization and neurocognitive binding in schizophrenia. Associations between AM perception and psychopathology as well as meaningful subgroups were sought. Circular and stroboscopic AM stimuli were presented to 68 schizophrenia spectrum patients and healthy participants. Psychopathology was measured using the Positive and Negative Syndrome Scale (PANSS). Psychopathology was related to AM perception differentially: Positive and disorganization symptoms were linked to reduced gestalt stability; negative symptoms, excitement and depression had opposite regression weights. Dimensions of psychopathology thus have opposing effects on gestalt perception. It was generally found that AM perception was closely associated with psychopathology. No difference existed between patients and controls, but two latent classes were found. Class A members who had low levels of AM stability made up the majority of inpatients and control subjects; such participants were generally young and male, with short reaction times. Class B typically contained outpatients and some control subjects; participants in class B were older and showed longer reaction times. Hence AM perceptual dysfunctions are not specific for schizophrenia, yet AM may be a promising stage marker.

Water Mediated Ligand Functional Group Cooperativity: The Contribution of a Methyl Group to Binding Affinity is Enhanced by a COO− Group Through Changes in the Structure and Thermo dynamics of the Hydration Waters of Ligand-Thermolysin Complexes

PubMed Central

Nasief, Nader N; Tan, Hongwei; Kong, Jing; Hangauer, David

2012-01-01

Ligand functional groups can modulate the contributions of one another to the ligand-protein binding thermodynamics, producing either positive or negative cooperativity. Data presented for four thermolysin phosphonamidate inhibitors demonstrate that the differential binding free energy and enthalpy caused by replacement of a H with a Me group, which binds in the well-hydrated S2′ pocket, are more favorable in presence of a ligand carboxylate. The differential entropy is however less favorable. Dissection of these differential thermodynamic parameters, X-ray crystallography, and density-functional theory calculations suggest that these cooperativities are caused by variations in the thermodynamics of the complex hydration shell changes accompanying the H→Me replacement. Specifically, the COO− reduces both the enthalpic penalty and the entropic advantage of displacing water molecules from the S2′ pocket, and causes a subsequent acquisition of a more enthalpically, less entropically, favorable water network. This study contributes to understanding the important role water plays in ligand-protein binding. PMID:22894131

Health-seeking behavior and hospital choice in China's New Cooperative Medical System.

PubMed

Brown, Philip H; Theoharides, Caroline

2009-07-01

Since the dissolution of the Rural Cooperative Medical System at the end of the commune period, illness has emerged as a leading cause of poverty in rural China. To address the poor state of health care, the Chinese government unveiled the New Cooperative Medical System in 2002. Because local governments have been given significant control over program design, fundamental characteristics of the program vary from one county to the next. These differences may influence the decision to seek health care as well as the choice of hospital conditional on that initial decision. In this paper, we use a nested logit model to analyze household survey data from 25 counties to analyze the determinants of such health-seeking behavior. We find that age, the share of household expenditures allocated to food consumption (a measure of relative income), and the presence of other sick people in the household negatively affect the decision to seek health care while disability has a positive influence. Further, conditional on seeking treatment, the reimbursement scheme in place in each county and the average daily expenditure associated with hospitalization strongly influence hospital choice.

Punishment as a means of competition: implications for strong reciprocity theory.

PubMed

Paál, Tünde; Bereczkei, Tamás

2015-01-01

Strong negative reciprocity, that is, sanctions imposed on norm violators at the punisher's own expense, has powerful cooperation-enhancing effects in both real-life and experimental game situations. However, it is plausible that punishment may obtain alternative roles depending on social context and the personality characteristics of participants. We examined the occurrence of punishing behavior among 80 subjects in a strongly competitive Public Goods game setting. Despite the punishment condition, the amount of the contributions decreased steadily during the game. The amount of contributions had no significant effect on received and imposed punishments. The results indicate that certain social contexts (in this case, intensive competition) exert modifying effects on the role that punishment takes on. Subjects punished each other in order to achieve a higher rank and a financially better outcome. Punishment primarily functioned as a means of rivalry, instead of as a way of second-order cooperation, as strong reciprocity suggests. These results indicate the need for the possible modification of the social conditions of punishment mechanisms described by the strong reciprocity theory as an evolutionary explanation of human cooperation.

Punishment as a Means of Competition: Implications for Strong Reciprocity Theory

PubMed Central

Paál, Tünde; Bereczkei, Tamás

2015-01-01

Strong negative reciprocity, that is, sanctions imposed on norm violators at the punisher’s own expense, has powerful cooperation-enhancing effects in both real-life and experimental game situations. However, it is plausible that punishment may obtain alternative roles depending on social context and the personality characteristics of participants. We examined the occurrence of punishing behavior among 80 subjects in a strongly competitive Public Goods game setting. Despite the punishment condition, the amount of the contributions decreased steadily during the game. The amount of contributions had no significant effect on received and imposed punishments. The results indicate that certain social contexts (in this case, intensive competition) exert modifying effects on the role that punishment takes on. Subjects punished each other in order to achieve a higher rank and a financially better outcome. Punishment primarily functioned as a means of rivalry, instead of as a way of second-order cooperation, as strong reciprocity suggests. These results indicate the need for the possible modification of the social conditions of punishment mechanisms described by the strong reciprocity theory as an evolutionary explanation of human cooperation. PMID:25811464

Gaining trust as well as respect in communicating to motivated audiences about science topics

PubMed Central

Fiske, Susan T.; Dupree, Cydney

2014-01-01

Expertise is a prerequisite for communicator credibility, entailing the knowledge and ability to be accurate. Trust also is essential to communicator credibility. Audiences view trustworthiness as the motivation to be truthful. Identifying whom to trust follows systematic principles. People decide quickly another’s apparent intent: Who is friend or foe, on their side or not, or a cooperator or competitor. Those seemingly on their side are deemed warm (friendly, trustworthy). People then decide whether the other is competent to enact those intents. Perception of scientists, like other social perceptions, involves inferring both their apparent intent (warmth) and capability (competence). To illustrate, we polled adults online about typical American jobs, rated as American society views them, on warmth and competence dimensions, as well as relevant emotions. Ambivalently perceived high-competence but low-warmth, “envied” professions included lawyers, chief executive officers, engineers, accountants, scientists, and researchers. Being seen as competent but cold might not seem problematic until one recalls that communicator credibility requires not just status and expertise but also trustworthiness (warmth). Other research indicates the risk from being enviable. Turning to a case study of scientific communication, another online sample of adults described public attitudes toward climate scientists specifically. Although distrust is low, the apparent motive to gain research money is distrusted. The literature on climate science communicators agrees that the public trusts impartiality, not persuasive agendas. Overall, communicator credibility needs to address both expertise and trustworthiness. Scientists have earned audiences’ respect, but not necessarily their trust. Discussing, teaching, and sharing information can earn trust to show scientists’ trustworthy intentions. PMID:25225372

Geohydrology of Test Well USW H-3, Yucca Mountain, Nye County, Nevada

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

Thordarson, W.; Rush, F.E.; Waddell, S.J.

Test well USW H-3 is one of several test wells drilled in the southwestern part of the Nevada Test Site in cooperation with the US Department of Energy for investigations related to the isolation of high-level radioactive wastes. All rocks penetrated by the well to a total depth of 1219 meters are volcanic tuff of Tertiary age. The composite hydraulic head in the zone 751 to 1219 meters was 733 meters above sea level, and at a depth below land surface of 751 meters. Below a depth of 1190 meters, the hydraulic head was 754 meters above sea level ormore » higher, suggesting an upward component of groundwater flow at the site. The most transmissive part of the saturated zone is in the upper part of the Tram Member of the Crater Flat Tuff in the depth interval from 809 to 841 meters, with an apparent transmissivity of about 7 x 10{sup -1} meter squared per day. The remainder of the penetrated rocks in the saturated zone, 841 to 1219 meters, has an apparent transmissivity of about 4 x 10{sup -1} meter squared per day. The most transmissive part of the lower depth interval is in the bedded tuff and Lithic Ridge Tuff, in the depth interval from 1108 to 1120 meters. The apparent hydraulic conductivity of the rocks in the lower depth interval from 841 to 1219 meters commonly ranges from about 10{sup -1} to 10{sup -4} meter per day. 32 references, 20 figures, 4 tables.« less

Gene interference regulates aquaporin-4 expression in swollen tissue of rats with cerebral ischemic edema

PubMed Central

Hu, Hui; Lu, Hong; He, Zhanping; Han, Xiangjun; Chen, Jing; Tu, Rong

2012-01-01

To investigate the effects of mRNA interference on aquaporin-4 expression in swollen tissue of rats with ischemic cerebral edema, and diagnose the significance of diffusion-weighted MRI, we injected 5 μL shRNA- aquaporin-4 (control group) or siRNA- aquaporin-4 solution (1:800) (RNA interference group) into the rat right basal ganglia immediately before occlusion of the middle cerebral artery. At 0.25 hours after occlusion of the middle cerebral artery, diffusion-weighted MRI displayed a high signal; within 2 hours, the relative apparent diffusion coefficient decreased markedly, aquaporin-4 expression increased rapidly, and intracellular edema was obviously aggravated; at 4 and 6 hours, the relative apparent diffusion coefficient slowly returned to control levels, aquaporin-4 expression slightly increased, and angioedema was observed. In the RNA interference group, during 0.25–6 hours after injection of siRNA- aquaporin-4 solution, the relative apparent diffusion coefficient slightly fluctuated and aquaporin-4 expression was upregulated; during 0.5–4 hours, the relative apparent diffusion coefficient was significantly higher, while aquaporin-4 expression was significantly lower when compared with the control group, and intracellular edema was markedly reduced; at 0.25 and 6 hours, the relative apparent diffusion coefficient and aquaporin-4 expression were similar when compared with the control group; obvious angioedema remained at 6 hours. Pearson's correlation test results showed that aquaporin-4 expression was negatively correlated with the apparent diffusion coefficient (r = −0.806, P < 0.01). These findings suggest that upregulated aquaporin-4 expression is likely to be the main molecular mechanism of intracellular edema and may be the molecular basis for decreased relative apparent diffusion coefficient. Aquaporin-4 gene interference can effectively inhibit the upregulation of aquaporin-4 expression during the stage of intracellular edema with time-effectiveness. Moreover, diffusion-weighted MRI can accurately detect intracellular edema. PMID:25657707

Apparent annual survival estimates of tropical songbirds better reflect life history variation when based on intensive field methods

USGS Publications Warehouse

Martin, Thomas E.; Riordan, Margaret M.; Repin, Rimi; Mouton, James C.; Blake, William M.

2017-01-01

AimAdult survival is central to theories explaining latitudinal gradients in life history strategies. Life history theory predicts higher adult survival in tropical than north temperate regions given lower fecundity and parental effort. Early studies were consistent with this prediction, but standard-effort netting studies in recent decades suggested that apparent survival rates in temperate and tropical regions strongly overlap. Such results do not fit with life history theory. Targeted marking and resighting of breeding adults yielded higher survival estimates in the tropics, but this approach is thought to overestimate survival because it does not sample social and age classes with lower survival. We compared the effect of field methods on tropical survival estimates and their relationships with life history traits.LocationSabah, Malaysian Borneo.Time period2008–2016.Major taxonPasseriformes.MethodsWe used standard-effort netting and resighted individuals of all social and age classes of 18 tropical songbird species over 8 years. We compared apparent survival estimates between these two field methods with differing analytical approaches.ResultsEstimated detection and apparent survival probabilities from standard-effort netting were similar to those from other tropical studies that used standard-effort netting. Resighting data verified that a high proportion of individuals that were never recaptured in standard-effort netting remained in the study area, and many were observed breeding. Across all analytical approaches, addition of resighting yielded substantially higher survival estimates than did standard-effort netting alone. These apparent survival estimates were higher than for temperate zone species, consistent with latitudinal differences in life histories. Moreover, apparent survival estimates from addition of resighting, but not from standard-effort netting alone, were correlated with parental effort as measured by egg temperature across species.Main conclusionsInclusion of resighting showed that standard-effort netting alone can negatively bias apparent survival estimates and obscure life history relationships across latitudes and among tropical species.

A successful education program for parents of infants with newly diagnosed sickle cell disease.

PubMed

Day, S; Brunson, G; Wang, W

1992-02-01

The most dramatic recent advance in the care of young children with sickle cell disease was the demonstration by a cooperative study that the use of oral penicillin prophylaxis is highly effective in decreasing the risk of pneumococcal sepsis. Subsequently, the need for more comprehensive education of the parents of these children to ensure compliance with penicillin administration has become apparent. Over the past 4 years, the Mid-South Sickle Cell Disease Program has used a seven-phase educational process for the parents of more than 200 infants with newly diagnosed sickle cell disease. This has resulted in excellent compliance and a marked decrease in the incidence of pneumococcal sepsis among sickle cell patients at our center.

Effects of increasing concentrations of an Escherichia coli phytase on the apparent ileal digestibility of amino acids and the apparent total tract digestibility of energy and nutrients in corn-soybean meal diets fed to growing pigs.

PubMed

She, Y; Sparks, J C; Stein, H H

2018-04-24

An experiment was conducted to test the hypothesis that inclusion of increasing concentrations of an Escherichia coli (E. coli) phytase to a corn-soybean meal (SBM) diet results in improved digestibility of DM, GE, CP, NDF, ADF, macro minerals, micro minerals, and AA. Twenty four growing barrows (initial BW: 37.0 ± 1.4 kg) were equipped with a T-cannula in the distal ileum and placed individually in metabolism crates, and allotted to a 2-period switch-back design with 6 diets and 4 replicate pigs per diet in each period. The positive control diet was a corn-SBM diet that contained limestone and dicalcium phosphate to meet the requirement for standardized total tract digestible (STTD) P and Ca (0.31% STTD P and 0.70% Ca). A negative control diet that was similar to the positive control diet with the exception that no dicalcium phosphate was used and formulated to contain 0.16% STTD P and 0.43% Ca. Four additional diets were formulated by adding 500, 1,000, 2,000, or 4,000 units of microbial phytase (FTU) to the negative control diet. Each period lasted 14 d. Fecal and urine samples were collected from the feed provided from d 6 to 11 of each period following 5 d of adaptation to the diets. Ileal digesta were collected for 8 h on d 13 and 14. Results indicated that addition of the E. coli phytase to the negative control diet tended to quadratically improve the apparent ileal digestibility (AID) of Phe (P = 0.086) and Asp (P = 0.054), and linearly increased (P < 0.05) the apparent total tract digestibility (ATTD) of ADF, K, and Fe. Microbial phytase also quadratically increased (P < 0.05) the ATTD of NDF and Mg, and linearly and quadratically increased (P < 0.05) the ATTD and retention of Ca and P. However, no effects of the phytase on ATTD of GE or the concentration of DE were observed. In conclusion, the increased absorption of several minerals including Ca, P, K, Mg, and Fe that was observed as increasing concentrations of an E. coli phytase were added to a corn-SBM meal diet indicates that the dietary provision of these minerals may be reduced if phytase is fed.

Use of positive and negative words in scientific PubMed abstracts between 1974 and 2014: retrospective analysis.

PubMed

Vinkers, Christiaan H; Tijdink, Joeri K; Otte, Willem M

2015-12-14

To investigate whether language used in science abstracts can skew towards the use of strikingly positive and negative words over time. Retrospective analysis of all scientific abstracts in PubMed between 1974 and 2014. The yearly frequencies of positive, negative, and neutral words (25 preselected words in each category), plus 100 randomly selected words were normalised for the total number of abstracts. Subanalyses included pattern quantification of individual words, specificity for selected high impact journals, and comparison between author affiliations within or outside countries with English as the official majority language. Frequency patterns were compared with 4% of all books ever printed and digitised by use of Google Books Ngram Viewer. Frequencies of positive and negative words in abstracts compared with frequencies of words with a neutral and random connotation, expressed as relative change since 1980. The absolute frequency of positive words increased from 2.0% (1974-80) to 17.5% (2014), a relative increase of 880% over four decades. All 25 individual positive words contributed to the increase, particularly the words "robust," "novel," "innovative," and "unprecedented," which increased in relative frequency up to 15,000%. Comparable but less pronounced results were obtained when restricting the analysis to selected journals with high impact factors. Authors affiliated to an institute in a non-English speaking country used significantly more positive words. Negative word frequencies increased from 1.3% (1974-80) to 3.2% (2014), a relative increase of 257%. Over the same time period, no apparent increase was found in neutral or random word use, or in the frequency of positive word use in published books. Our lexicographic analysis indicates that scientific abstracts are currently written with more positive and negative words, and provides an insight into the evolution of scientific writing. Apparently scientists look on the bright side of research results. But whether this perception fits reality should be questioned. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Some mechanistic requirements for major transitions.

PubMed

Schuster, Peter

2016-08-19

Major transitions in nature and human society are accompanied by a substantial change towards higher complexity in the core of the evolving system. New features are established, novel hierarchies emerge, new regulatory mechanisms are required and so on. An obvious way to achieve higher complexity is integration of autonomous elements into new organized systems whereby the previously independent units give up their autonomy at least in part. In this contribution, we reconsider the more than 40 years old hypercycle model and analyse it by the tools of stochastic chemical kinetics. An open system is implemented in the form of a flow reactor. The formation of new dynamically organized units through integration of competitors is identified with transcritical bifurcations. In the stochastic model, the fully organized state is quasi-stationary whereas the unorganized state corresponds to a population with natural selection. The stability of the organized state depends strongly on the number of individual subspecies, n, that have to be integrated: two and three classes of individuals, [Formula: see text] and [Formula: see text], readily form quasi-stationary states. The four-membered deterministic dynamical system, [Formula: see text], is stable but in the stochastic approach self-enhancing fluctuations drive it into extinction. In systems with five and more classes of individuals, [Formula: see text], the state of cooperation is unstable and the solutions of the deterministic ODEs exhibit large amplitude oscillations. In the stochastic system self-enhancing fluctuations lead to extinction as observed with [Formula: see text] Interestingly, cooperative systems in nature are commonly two-membered as shown by numerous examples of binary symbiosis. A few cases of symbiosis of three partners, called three-way symbiosis, have been found and were analysed within the past decade. Four-way symbiosis is rather rare but was reported to occur in fungus-growing ants. The model reported here can be used to illustrate the interplay between competition and cooperation whereby we obtain a hint on the role that resources play in major transitions. Abundance of resources seems to be an indispensable prerequisite of radical innovation that apparently needs substantial investments. Economists often claim that scarcity is driving innovation. Our model sheds some light on this apparent contradiction. In a nutshell, the answer is: scarcity drives optimization and increase in efficiency but abundance is required for radical novelty and the development of new features.This article is part of the themed issue 'The major synthetic evolutionary transitions'. © 2016 The Author(s).

Cooperative management of riparian forest habitats to maintain biological quality and ecosystem integrity

Treesearch

David Deardorff; Kathryn Wadsworth

1996-01-01

The New Mexico State Land Office has initiated a rare plant survey of state trust land, an inventory and assessment of riparian areas on the trust land, and the development of a biological resources data base and information management system. Some riparian sites that still belong to the trust have been negatively impacted by livestock such that biological quality and...

Military Contractors - Too Much Dependence

DTIC Science & Technology

2008-03-19

or companies) with which they have established a level of familiarity. There is also potential for the negative effects of quid pro quo . All of...promotes integrity, physical strength, health, unity, cooperation and teamwork. It combats stereotyping and sexual harassment . It fosters in its...in their reliance on contractors. The Office of the Secretary of Defense should commission a study on the pros and cons of contracting in order to

Evolution of Cooperation in Continuous Prisoner's Dilemma Games on Barabasi—Albert Networks with Degree-Dependent Guilt Mechanism

NASA Astrophysics Data System (ADS)

Wang, Xian-Jia; Quan, Ji; Liu, Wei-Bing

2012-05-01

This paper studies the continuous prisoner's dilemma games (CPDG) on Barabasi—Albert (BA) networks. In the model, each agent on a vertex of the networks makes an investment and interacts with all of his neighboring agents. Making an investment is costly, but which benefits its neighboring agents, where benefit and cost depend on the level of investment made. The payoff of each agent is given by the sum of payoffs it receives in its interactions with all its neighbors. Not only payoff, individual's guilty emotion in the games has also been considered. The negative guilty emotion produced in comparing with its neighbors can reduce the utility of individuals directly. We assume that the reduction amount depends on the individual's degree and a baseline level parameter. The group's cooperative level is characterized by the average investment of the population. Each player makes his investment in the next step based on a convex combination of the investment of his best neighbors in the last step, his best history strategies in the latest steps which number is controlled by a memory length parameter, and a uniformly distributed random number. Simulation results show that this degree-dependent guilt mechanism can promote the evolution of cooperation dramatically comparing with degree-independent guilt or no guilt cases. Imitation, memory, uncertainty coefficients and network structure also play determinant roles in the cooperation level of the population. All our results may shed some new light on studying the evolution of cooperation based on network reciprocity mechanisms.

The roles of tolerance in the evolution, maintenance and breakdown of mutualism

NASA Astrophysics Data System (ADS)

Edwards, David P.

2009-10-01

Tolerance strategies are cost-reduction mechanisms that enable organisms to recover some of the fitness lost to damage, but impose limited or no cost on antagonists. They are frequently invoked in studies of plant-herbivore and of host-parasite interactions, but the possible roles of tolerance in mutualism (interspecific cooperation) have yet to be thoroughly examined. This review identifies candidate roles for tolerance in the evolution, maintenance and breakdown of mutualism. Firstly, by reducing the cost of damage, tolerance provides a key pathway by which pre-mutualistic hosts can reduce the cost of association with their parasites, promoting cooperation. This holds for the evolution of ‘evolved dependency’ type mutualism, where a host requires an antagonist that does not direct any reward to their partner for some resource, and of ‘outright mutualism’, where participants directly trade benefits. Secondly, in outright mutualism, tolerance might maintain cooperation by reducing the cost of a persisting negative trait in a symbiotic partner. Finally, the evolution of tolerance might also provide a pathway out of mutualism because the host could evolve a cheaper alternative to continued cooperation with its mutualistic partner, permitting autonomy. A key consequence of tolerance is that it contrasts with partner choice mechanisms that impose large costs on cheats, and I highlight understanding any trade-off between tolerance and partner choice as an important research topic in the evolution of cooperation. I conclude by identifying tolerance as part of a more general phenomenon of co-adaptation in mutualism and parasitism that drives the evolution of the cost/benefit ratio from the interaction.

Equilibrium binding behavior of magnesium to wall teichoic acid.

PubMed

Thomas, Kieth J; Rice, Charles V

2015-10-01

Peptidoglycan and teichoic acids are the major cell wall components of Gram-positive bacteria that obtain and sequester metal ions required for biochemical processes. The delivery of metals to the cytoplasmic membrane is aided by anionic binding sites within the peptidoglycan and along the phosphodiester polymer of teichoic acid. The interaction with metals is a delicate balance between the need for attraction and ion diffusion to the membrane. Likewise, metal chelation from the extracellular fluid must initially have strong binding energetics that weaken within the cell wall to enable ion release. We employed atomic absorption and equilibrium dialysis to measure the metal binding capacity and metal binding affinity of wall teichoic acid and Mg2+. Data show that Mg2+ binds to WTA with a 1:2Mg2+ to phosphate ratio with a binding capacity of 1.27 μmol/mg. The affinity of Mg2+ to WTA was also found to be 41×10(3) M(-1) at low metal concentrations and 1.3×10(3) M(-1) at higher Mg2+ concentrations due to weakening electrostatic effects. These values are lower than the values describing Mg2+ interactions with peptidoglycan. However, the binding capacity of WTA is 4 times larger than peptidoglycan. External WTA initially binds metals with positive cooperativity, but metal binding switches to negative cooperativity, whereas interior WTA binds metals with only negative cooperativity. The relevance of this work is to describe changes in metal binding behavior depending on environment. When metals are sparse, chelation is strong to ensure survival yet the binding weakens when essential minerals are abundant. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessing the advantage of morphological changes in Candida albicans: a game theoretical study

PubMed Central

Tyc, Katarzyna M.; Kühn, Clemens; Wilson, Duncan; Klipp, Edda

2014-01-01

A range of attributes determines the virulence of human pathogens. During interactions with their hosts, pathogenic microbes often undergo transitions between distinct stages, and the ability to switch between these can be directly related to the disease process. Understanding the mechanisms and dynamics of these transitions is a key factor in understanding and combating infectious diseases. The human fungal pathogen Candida albicans exhibits different morphotypes at different stages during the course of infection (candidiasis). For example, hyphae are considered to be the invasive form, which causes tissue damage, while yeast cells are predominant in the commensal stage. Here, we described interactions of C. albicans with its human host in a game theoretic model. In the game, players are fungal cells. Each fungal cell can adopt one of the two strategies: to exist as a yeast or hyphal cell. We characterized the ranges of model parameters in which the coexistence of both yeast and hyphal forms is plausible. Stability analysis of the system showed that, in theory, a reduced ability of the host to specifically recognize yeast and hyphal cells can result in bi-stability of the microbial populations' profile. Inspired by the model analysis we reasoned that the types of microbial interactions can change during invasive candidiasis. We found that positive cooperation among fungal cells occurs in mild infections and an enhanced tendency to invade the host is associated with negative cooperation. The model can easily be extended to multi-player systems with direct application to identifying individuals that enhance either positive or negative cooperation. Results of the modeling approach have potential application in developing treatment strategies. PMID:24567730

Structure, High Affinity, and Negative Cooperativity of the Escherichia coli Holo-(Acyl Carrier Protein):Holo-(Acyl Carrier Protein) Synthase Complex.

PubMed

Marcella, Aaron M; Culbertson, Sannie J; Shogren-Knaak, Michael A; Barb, Adam W

2017-11-24

The Escherichia coli holo-(acyl carrier protein) synthase (ACPS) catalyzes the coenzyme A-dependent activation of apo-ACPP to generate holo-(acyl carrier protein) (holo-ACPP) in an early step of fatty acid biosynthesis. E. coli ACPS is sufficiently different from the human fatty acid synthase to justify the development of novel ACPS-targeting antibiotics. Models of E. coli ACPS in unliganded and holo-ACPP-bound forms solved by X-ray crystallography to 2.05and 4.10Å, respectively, revealed that ACPS bound three product holo-ACPP molecules to form a 3:3 hexamer. Solution NMR spectroscopy experiments validated the ACPS binding interface on holo-ACPP using chemical shift perturbations and by determining the relative orientation of holo-ACPP to ACPS by fitting residual dipolar couplings. The binding interface is organized to arrange contacts between positively charged ACPS residues and the holo-ACPP phosphopantetheine moiety, indicating product contains more stabilizing interactions than expected in the enzyme:substrate complex. Indeed, holo-ACPP bound the enzyme with greater affinity than the substrate, apo-ACPP, and with negative cooperativity. The first equivalent of holo-ACPP bound with a K D =62±13nM, followed by the binding of two more equivalents of holo-ACPP with K D =1.2±0.2μM. Cooperativity was not observed for apo-ACPP which bound with K D =2.4±0.1μM. Strong product binding and high levels of holo-ACPP in the cell identify a potential regulatory role of ACPS in fatty acid biosynthesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessing the impact of nano- and micro-scale zerovalent iron particles on soil microbial activities: particle reactivity interferes with assay conditions and interpretation of genuine microbial effects.

PubMed

Cullen, Laurence G; Tilston, Emma L; Mitchell, Geoff R; Collins, Chris D; Shaw, Liz J

2011-03-01

The effects of nano-scale and micro-scale zerovalent iron (nZVI and mZVI) particles on general (dehydrogenase and hydrolase) and specific (ammonia oxidation potential, AOP) activities mediated by the microbial community in an uncontaminated soil were examined. nZVI (diameter 12.5 nm; 10 mg g⁻¹ soil) apparently inhibited AOP and nZVI and mZVI apparently stimulated dehydrogenase activity but had minimal influence on hydrolase activity. Sterile experiments revealed that the apparent inhibition of AOP could not be interpreted as such due to the confounding action of the particles, whereas, the nZVI-enhanced dehydrogenase activity could represent the genuine response of a stimulated microbial population or an artifact of ZVI reactivity. Overall, there was no evidence for negative effects of nZVI or mZVI on the processes studied. When examining the impact of redox active particles such as ZVI on microbial oxidation-reduction reactions, potential confounding effects of the test particles on assay conditions should be considered. Copyright © 2010 Elsevier Ltd. All rights reserved.

Evolving Hořava cosmological horizons

NASA Astrophysics Data System (ADS)

Fathi, Mohsen; Mohseni, Morteza

2016-09-01

Several sets of radially propagating null congruence generators are exploited in order to form 3-dimensional marginally trapped surfaces, referred to as black hole and cosmological apparent horizons in a Hořava universe. Based on this method, we deal with the characteristics of the 2-dimensional space-like spheres of symmetry and the peculiarities of having trapping horizons. Moreover, we apply this method in standard expanding and contracting FLRW cosmological models of a Hořava universe to investigate the conditions under which the extra parameters of the theory may lead to trapped/anti-trapped surfaces both in the future and in the past. We also include the cases of negative time, referred to as the finite past, and discuss the formation of anti-trapped surfaces inside the cosmological apparent horizons.

The Role of Prosocialness and Trust in the Consumption of Water as a Limited Resource.

PubMed

Cuadrado, Esther; Tabernero, Carmen; García, Rocío; Luque, Bárbara; Seibert, Jan

2017-01-01

This research analyzes the role of prosocialness and trust in the use of water as a limited resource under situations of competition or cooperation. For this purpose, 107 participants played the role of farmers and made decisions about irrigating their fields in the web-based multiplayer game Irrigania. Before the simulation exercise, participants' prosocialness and trust levels were evaluated and they were randomly assigned to an experimental condition (competition or cooperation). Repeated measures analysis, using the 10 fields and the experimental conditions as factors, showed that, in the cooperation condition, farmers and their villages used a less selfish strategy to cultivate their fields, which produced greater benefits. Under competition, benefits to farmers and their villages were reduced over time. Mediational analysis shows that the selfish irrigation strategy fully mediated the relationship between prosocialness and accumulated profits; prosocial individuals choose less selfish irrigation strategies and, in turn, accumulated more benefit. Moreover, moderation analysis shows that trust moderated the link between prosocialness and water use strategy by strengthening the negative effect of prosocialness on selection of selfish strategies. The implications of these results highlight the importance of promoting the necessary trust to develop prosocial strategies in collectives; therefore, the efficacy of interventions, such as the creation of cooperative educational contexts or organization of collective actions with groups affected by water scarcity, are discussed.

Fundamental properties of cooperative contagion processes

NASA Astrophysics Data System (ADS)

Chen, Li; Ghanbarnejad, Fakhteh; Brockmann, Dirk

2017-10-01

We investigate the effects of cooperativity between contagion processes that spread and persist in a host population. We propose and analyze a dynamical model in which individuals that are affected by one transmissible agent A exhibit a higher than baseline propensity of being affected by a second agent B and vice versa. The model is a natural extension of the traditional susceptible-infected-susceptible model used for modeling single contagion processes. We show that cooperativity changes the dynamics of the system considerably when cooperativity is strong. The system exhibits discontinuous phase transitions not observed in single agent contagion, multi-stability, a separation of the traditional epidemic threshold into different thresholds for inception and extinction as well as hysteresis. These properties are robust and are corroborated by stochastic simulations on lattices and generic network topologies. Finally, we investigate wave propagation and transients in a spatially extended version of the model and show that especially for intermediate values of baseline reproduction ratios the system is characterized by various types of wave-front speeds. The system can exhibit spatially heterogeneous stationary states for some parameters and negative front speeds (receding wave fronts). The two agent model can be employed as a starting point for more complex contagion processes, involving several interacting agents, a model framework particularly suitable for modeling the spread and dynamics of microbiological ecosystems in host populations.

The Role of Prosocialness and Trust in the Consumption of Water as a Limited Resource

PubMed Central

Cuadrado, Esther; Tabernero, Carmen; García, Rocío; Luque, Bárbara; Seibert, Jan

2017-01-01

This research analyzes the role of prosocialness and trust in the use of water as a limited resource under situations of competition or cooperation. For this purpose, 107 participants played the role of farmers and made decisions about irrigating their fields in the web-based multiplayer game Irrigania. Before the simulation exercise, participants’ prosocialness and trust levels were evaluated and they were randomly assigned to an experimental condition (competition or cooperation). Repeated measures analysis, using the 10 fields and the experimental conditions as factors, showed that, in the cooperation condition, farmers and their villages used a less selfish strategy to cultivate their fields, which produced greater benefits. Under competition, benefits to farmers and their villages were reduced over time. Mediational analysis shows that the selfish irrigation strategy fully mediated the relationship between prosocialness and accumulated profits; prosocial individuals choose less selfish irrigation strategies and, in turn, accumulated more benefit. Moreover, moderation analysis shows that trust moderated the link between prosocialness and water use strategy by strengthening the negative effect of prosocialness on selection of selfish strategies. The implications of these results highlight the importance of promoting the necessary trust to develop prosocial strategies in collectives; therefore, the efficacy of interventions, such as the creation of cooperative educational contexts or organization of collective actions with groups affected by water scarcity, are discussed. PMID:28533760

Cross-bridge kinetics, cooperativity, and negatively strained cross- bridges in vertebrate smooth muscle. A laser-flash photolysis study

PubMed Central

1988-01-01

The effects of laser-flash photolytic release of ATP from caged ATP [P3- 1(2-nitrophenyl)ethyladenosine-5'-triphosphate] on stiffness and tension transients were studied in permeabilized guinea pig protal vein smooth muscle. During rigor, induced by removing ATP from the relaxed or contracting muscles, stiffness was greater than in relaxed muscle, and electron microscopy showed cross-bridges attached to actin filaments at an approximately 45 degree angle. In the absence of Ca2+, liberation of ATP (0.1-1 mM) into muscles in rigor caused relaxation, with kinetics indicating cooperative reattachment of some cross- bridges. Inorganic phosphate (Pi; 20 mM) accelerated relaxation. A rapid phase of force development, accompanied by a decline in stiffness and unaffected by 20 mM Pi, was observed upon liberation of ATP in muscles that were released by 0.5-1.0% just before the laser pulse. This force increment observed upon detachment suggests that the cross- bridges can bear a negative tension. The second-order rate constant for detachment of rigor cross-bridges by ATP, in the absence of Ca2+, was estimated to be 0.1-2.5 X 10(5) M-1s-1, which indicates that this reaction is too fast to limit the rate of ATP hydrolysis during physiological contractions. In the presence of Ca2+, force development occurred at a rate (0.4 s-1) similar to that of intact, electrically stimulated tissue. The rate of force development was an order of magnitude faster in muscles that had been thiophosphorylated with ATP gamma S before the photochemical liberation of ATP, which indicates that under physiological conditions, in non-thiophosphorylated muscles, light-chain phosphorylation, rather than intrinsic properties of the actomyosin cross-bridges, limits the rate of force development. The release of micromolar ATP or CTP from caged ATP or caged CTP caused force development of up to 40% of maximal active tension in the absence of Ca2+, consistent with cooperative attachment of cross-bridges. Cooperative reattachment of dephosphorylated cross-bridges may contribute to force maintenance at low energy cost and low cross-bridge cycling rates in smooth muscle. PMID:3373178

Climate-driven tree mortality: insights from the pinon pine die-off in the United States

Treesearch

Jeffrey A. Hicke; Melanie J. B. Zeppel

2013-01-01

The global climate is changing, and a range of negative effects on plants has already been observed and will likely continue into the future. One of the most apparent consequences of climate change is widespread tree mortality (Fig. 1). Extensive tree die-offs resulting from recent climate change have been documented across a range of forest types on all forested...

Religion: A Missing Component of Professional Military Education

DTIC Science & Technology

2015-01-01

dispute systems designer, researcher, and pro- fessor. Tom has consulted for private, civic , religious, and community organizations. Dr. Matyók has...levels. Presently, there is an apparent disconnect between how the U.S. Army perceives religion and the ways in which military officers are schooled...neither positive nor negative, it simply is. The regular friction of social life manifests itself as conflict at different levels; interpersonal

Low soil moisture during hot periods drives apparent negative temperature sensitivity of soil respiration in a dryland ecosystem: A multi-model comparison

USGS Publications Warehouse

Tucker, Colin; Reed, Sasha C.

2016-01-01

Arid and semiarid ecosystems (drylands) may dominate the trajectory of biosphere-to-atmosphere carbon (C) flux over the coming century. Accordingly, understanding dryland CO2 efflux controls is important for understanding C cycling at the global-scale: key unknowns regarding how temperature and moisture interact to regulate dryland C cycling remain. Further, the patchiness of dryland vegetation can create ‘islands of fertility’, with spatially heterogeneous rates of soil respiration (Rs). At our study site in southeastern Utah, USA we added or removed litter (0 to 650% of control) in paired plots that were either associated with a shrub or with interspaces between vascular plants. We measured Rs, soil temperature, and water content (θ) on eight sampling dates between October 2013 and November 2014. Rs was highest following monsoon rains in late summer when soil temperature was ~30°C. During mid-summer, Rs was low, associated with high soil temperatures (>40°C), resulting in an apparent negative temperature sensitivity of Rs at high temperatures, and positive temperature sensitivity at low-moderate temperatures. We used Bayesian statistical methods to compare multiple competing models capturing a wide range of hypothesized relationships between temperature, moisture, and Rs. The best fit model indicates apparent negative temperature sensitivity of soil respiration at high temperatures reflects the control of soil moisture – not high temperatures – in limiting Rs. The modeled Q10 ranged from 2.7 at 5°C to 1.4 at 45°C. Litter addition had no effect on temperature sensitivity or reference respiration (Rref = Rs at 20°C and optimum moisture) beneath shrubs, and little effect on Rref in interspaces, yet Rref was 1.5 times higher beneath shrubs than in interspaces. Together, these results suggest reduced Rs often observed at high temperatures in drylands is dominated by the control of moisture, and that variable litter inputs – at least over the short-term – exert minimal control over Rs.

The relationship between habitat characteristics and demographic performance of northern spotted owls in southern Oregon

USGS Publications Warehouse

Dugger, Katie M.; Wagner, Frank; Anthony, Robert G.; Olson, Gail S.

2005-01-01

We used data from Northern Spotted Owl (Strix occidentalis caurina) territories to model the effects of habitat (particularly intermediate-aged forest stand types), climate, and nonhabitat covariates (i.e., age, sex) on owl reproductive rate and apparent survival in southwestern Oregon. Our best model for reproductive rate included an interaction between a cyclic, annual time trend and male breeding experience, with higher reproductive rates in even years compared to odd, particularly for males with previous breeding experience. Reproductive rate was also negatively related to the amount of winter precipitation and positively related to the proportion of old-growth forest near the owl territory center. Apparent survival was not associated with age, sex, climate or any of the intermediate-aged forest types, but was positively associated with the proportion of older forest near the territory center in a pseudothreshold pattern. The quadratic structure of the proportion of nonhabitat farther from the nest or primary roost site was also part of our best survival model. Survival decreased dramatically when the amount of nonhabitat exceeded ∼50%. Habitat fitness potential estimates (λ̂h) for 97 owl territories ranged from 0.29–1.09, with a mean of 0.86 ± 0.02. Owl territories with habitat fitness potentials <1.0 were generally characterized by <40%–50% old forest habitat near the territory center. Our results indicate that both apparent survival and reproductive rate are positively associated with older forest types close to the nest or primary roost site. We found no support for either a positive or negative direct effect of intermediate-aged forests on either survival or reproductive rate.

Bioavailability of trace elements in beans and zinc-biofortified wheat in pigs.

PubMed

Carlson, Dorthe; Nørgaard, Jan Værum; Torun, Bulent; Cakmak, Ismail; Poulsen, Hanne Damgaard

2012-12-01

The objectives of this experiment were to study bioavailability of trace elements in beans and wheat containing different levels of zinc and to study how the water solubility of trace elements was related to the bioavailability in pigs. Three wheat and two bean types were used: wheat of Danish origin as a control (CtrlW), two Turkish wheat types low (LZnW) and high (HZnW) in zinc, a common bean (Com), and a faba bean (Faba). Two diets were composed by combining 81 % CtrlW and 19 % Com or Faba beans. Solubility was measured as the trace element concentration in the supernatant of feedstuffs, and diets incubated in distilled water at pH 4 and 38°C for 3 h. The bioavailability of zinc and copper of the three wheat types and the two bean-containing diets were evaluated in the pigs by collection of urine and feces for 7 days. The solubility of zinc was 34-63 %, copper 18-42 %, and iron 3-11 %. The zinc apparent digestibility in pigs was similar in the three wheat groups (11-14 %), but was significantly higher in the CtrlW+Faba group (23 %) and negative in the CtrlW+Com group (-30 %). The apparent digestibility of copper was higher in the HZnW (27 %) and CtrlW+Faba (33 %) groups than in the CtrlW (17 %) and LZnW (18 %) groups. The apparent copper digestibility of the CtrlW+Com diet was negative (-7 %). The solubility and digestibility results did not reflect the concentration in feedstuffs. The in vitro results of water solubility showed no relationship to the results of trace mineral bioavailability in pigs.

Effects of organic plant oils and role of oxidation on nutrient utilization in juvenile rainbow trout (Oncorhynchus mykiss).

PubMed

Lund, I; Dalsgaard, J; Jacobsen, C; Hansen, J H; Holm, J; Jokumsen, A

2013-03-01

Producing organic fish diets requires that the use of both fishmeal and fish oil (FO) be minimized and replaced by sustainable, organic sources. The purpose of the present study was to replace FO with organic oils and evaluate the effects on feed intake, feed conversion ratio (FCR), daily specific growth rate (SGR) and nutrient digestibility in diets in which fishmeal protein was partly substituted by organic plant protein concentrates. It is prohibited to add antioxidants to organic oils, and therefore the effects of force-oxidizing the oils (including FO) on feed intake and nutrient digestibility was furthermore examined. Four organic oils with either a relatively high or low content of polyunsaturated fatty acids were considered: linseed oil, rapeseed oil, sunflower oil and grapeseed oil. Substituting FO with organic oils did not affect feed intake (P > 0.05), FCR or SGR (P > 0.05) despite very different dietary fatty acid profiles. All organic plant oils had a positive effect on apparent lipid digestibility compared with the FO diet (P < 0.05), whereas there were no effects on the apparent digestibility of other macronutrients when compared with the FO diet (P > 0.05). Organic vegetable oils did not undergo auto-oxidation as opposed to the FO, and the FO diet consequently had a significantly negative effect on the apparent lipid digestibility. Feed intake was not affected by oxidation of any oils. In conclusion, the study demonstrated that it is possible to fully substitute FO with plant-based organic oils without negatively affecting nutrient digestibility and growth performance. Furthermore, plant-based organic oils are less likely to oxidize than FOs, prolonging the shelf life of such organic diets.

Toward Reducing Ageism: PEACE (Positive Education about Aging and Contact Experiences) Model.

PubMed

Levy, Sheri R

2018-03-19

The population of older adults is growing worldwide. Negative ageism (negative attitudes and behavior toward older adults) is a serious international concern that negatively influences not only older adults but also individuals across the age continuum. This article proposes and examines the application of an integrative theoretical model across empirical evidence in the literature on ageism in psychology, medicine, social work, and sociology. The proposed Positive Education about Aging and Contact Experiences (PEACE) model focuses on 2 key contributing factors expected to reduce negative ageism: (a) education about aging including facts on aging along with positive older role models that dispel negative and inaccurate images of older adulthood; and (b) positive contact experiences with older adults that are individualized, provide or promote equal status, are cooperative, involve sharing of personal information, and are sanctioned within the setting. These 2 key contributing factors have the potential to be interconnected and work together to reduce negative stereotypes, aging anxiety, prejudice, and discrimination associated with older adults and aging. This model has implications for policies and programs that can improve the health and well-being of individuals, as well as expand the residential, educational, and career options of individuals across the age continuum.

Cynical beliefs about human nature and income: Longitudinal and cross-cultural analyses.

PubMed

Stavrova, Olga; Ehlebracht, Daniel

2016-01-01

Based on the existing literature on worldview beliefs, cynical hostility, and Machiavellian cynicism, we suggest that holding cynical beliefs about human nature can be detrimental for individuals' income. Cynical individuals are more likely to avoid cooperation and trust or to overinvest in monitoring, control, and other means of protection from potential exploitation. As a result, they are more likely to forgo valuable opportunities for cooperation and consequently less likely to reap the benefits of joint efforts and mutual help compared with their less cynical counterparts. Studies 1 and 2, using nationally representative longitudinal surveys of the American population, show that individuals who endorsed cynical beliefs about human nature at baseline earned comparatively lower incomes 9 (Study 1) and 2 (Study 2) years later. In Study 3, applying a multilevel model of change to a nationally representative panel study of the German population, we show that cynical beliefs at baseline undermined an income increase in the course of the following 9 years. In Study 4, the negative effect of cynical beliefs on income proved to be independent of individual differences in the Big Five personality dimensions. Study 5 provided the first tentative evidence of the hypothesized mechanism underlying this effect. Using survey data from 41 countries, it revealed that the negative effect of cynical beliefs on income is alleviated in sociocultural contexts with low levels of prosocial behavior, high homicide rates and high overall societal cynicism levels. Holding cynical beliefs about others has negative economic outcomes unless such beliefs hold true. (c) 2016 APA, all rights reserved).

Potential negative impacts of nuclear activities on local economies: Rethinking the issue

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

Metz, W.C.

1994-10-01

Surveys of public opinion about perceptions of risk associated with the nuclear fuel cycle have shown that the public professes a widespread feeling of dread, a fear of associated stigmas, and a concern about possible catastrophic nuclear accidents. Various interest groups and state governments that oppose congressionally mandated siting of centralized high-level radioactive waste (HLW) storage and disposal facilities are using this negative imagery to create a powerful, emotional obstacle to the siting process. From statistical analyses of images and location preferences, researchers have claimed that possible significant economic losses could potentially accompany the siting of HLW facilities. However, severalmore » paradoxes, or self-contradictory statements, apparently exist between the responses expressed in surveys and the actual economic and demographic behavior evidenced in the marketplace. Federal policymakers need to evaluate whether the request for a change in siting policy is based on subjective fear of a potential negative economic effect or on proven negative effects. Empirically observed behavior does not support predicted negative economic effects based on survey responses. 41 refs.« less

Plasmids as stochastic model systems

NASA Astrophysics Data System (ADS)

Paulsson, Johan

2003-05-01

Plasmids are self-replicating gene clusters present in on average 2-100 copies per bacterial cell. To reduce random fluctuations and thereby avoid extinction, they ubiquitously autoregulate their own synthesis using negative feedback loops. Here I use van Kampen's Ω-expansion for a two-dimensional model of negative feedback including plasmids and ther replication inhibitors. This analytically summarizes the standard perspective on replication control -- including the effects of sensitivity amplification, exponential time-delays and noisy signaling. I further review the two most common molecular sensitivity mechanisms: multistep control and cooperativity. Finally, I discuss more controversial sensitivity schemes, such as noise-enhanced sensitivity, the exploitation of small-number combinatorics and double-layered feedback loops to suppress noise in disordered environments.

Ghosts of the past and dreams of the future: the impact of temporal focus on responses to contextual ingroup devaluation.

PubMed

Rabinovich, Anna; Morton, Thomas A

2012-03-01

The authors investigated the impact of temporal focus on group members' responses to contextual ingroup devaluation. Four experimental studies demonstrated that following an induction of negative ingroup evaluation, participants primed with a past temporal focus reported behavioral intentions more consistent with this negative appraisal than participants primed with a future temporal focus. This effect was apparent only when a negative (but not a positive) evaluation was induced, and only among highly identified group members. Importantly, the interplay between temporal focus and group identification on relevant intentions was mediated by individual self-esteem, suggesting that focus on the future may be conducive to separating negative ingroup appraisals from individual self-evaluations. Taken together, the findings suggest that high identifiers' responses to ingroup evaluations may be predicated on their temporal focus: A focus on the past may lock such individuals within their group's history, whereas a vision of the future may open up opportunities for change.

From "herbal highs" to the "heroin of cannabis": Exploring the evolving discourse on synthetic cannabinoid use in a Norwegian Internet drug forum.

PubMed

Bilgrei, Ola Røed

2016-03-01

In the early 2000s, online vendors began selling an array of so-called "legal highs"--apparently organic produce made from exotic herbs. Simultaneously, members of online drug discussion forums began to debate the alleged effects of the new drugs, creating an enormous base of user-derived information based on personal experiences. This study combines the historical data spanning a seven-year period derived from a Norwegian drug discussion forum about synthetic cannabinoids and interviews with 14 male forum members who all had experience with the drug. By combining the two sources, this study reveals not only the evolving discourse on synthetic cannabinoid use but also how forum members related to the online information that they gathered and co-produced. Analysis of the evolving online discourse revealed three distinct phases. The first was an enthusiastic phase, with users embracing the new drugs. The second was a phase characterized by growing ambivalence and scepticism towards use of the drugs. The third was one in which members of the community rejected the new drugs based on negative reviews from users. The analysis displays the communal process whereby members co-operate in the exchange of an extensive body of knowledge accumulated about synthetic cannabinoids, and the way in which this evolving discourse influences members of the forum in their views and representations of the drugs. Paradoxically, the online discussions of synthetic cannabinoids, which had great significance for their proliferation when they were initially introduced to the market, now seem to be a deterrent. The role of online drug communities in the development of new drug trends should receive renewed attention. Copyright © 2016 Elsevier B.V. All rights reserved.

Safety and pharmacokinetics of ramucirumab in combination with docetaxel in Japanese patients with locally advanced or metastatic breast cancer: a Phase Ib study.

PubMed

Masuda, Norikazu; Iwata, Hiroji; Aogi, Kenjiro; Xu, Yihuan; Ibrahim, Ayman; Gao, Ling; Dalal, Rita; Yoshikawa, Reigetsu; Sasaki, Yasutsuna

2016-12-01

The primary objective of this study was to investigate the safety and tolerability and to confirm the recommended dose of the anti-vascular endothelial growth factor receptor 2 monoclonal antibody ramucirumab in combination with docetaxel in Japanese patients with metastatic/locally advanced breast cancer. In this multicenter, single-arm, Phase Ib trial, eligibility criteria included: 20 years or older, Eastern Cooperative Oncology Group performance status of 0/1 and confirmed diagnosis of human epidermal growth factor receptor 2-negative metastatic/locally recurrent inoperable breast adenocarcinoma. Patients received docetaxel (75 mg/m 2 ) followed by ramucirumab (10 mg/kg) on Day 1 of 21-day cycles. Recommended dose was defined as <33% dose-limiting toxicities in dose-limiting toxicity-evaluable patients in Cycle 1. The safety, pharmacokinetics, immunogenicity and antitumor activity were examined. Seven patients were treated. Most adverse events were mild to moderate. Two patients during Cycle 1 experienced a dose-limiting toxicity; one patient each experienced Grade 3 febrile neutropenia and Grade 3 gingivitis. Both dose-limiting toxicities subsequently resolved. No patients discontinued study therapies during Cycle 1. Four serious adverse events were possibly related to ramucirumab in combination with docetaxel. Anti-ramucirumab antibodies were not detected. Pharmacokinetic analysis revealed low total body clearance and long apparent terminal elimination half-life (~7-12 days). Partial response was reported in four patients. The combination of ramucirumab and docetaxel was tolerable in female Japanese patients with breast cancer. Ramucirumab 10 mg/kg in combination with docetaxel (75 mg/m 2 ) was confirmed as the recommended dose among Japanese patients, supporting its use in future studies. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A nomogram for predicting complications in patients with solid tumours and seemingly stable febrile neutropenia

PubMed Central

Fonseca, Paula Jiménez; Carmona-Bayonas, Alberto; García, Ignacio Matos; Marcos, Rosana; Castañón, Eduardo; Antonio, Maite; Font, Carme; Biosca, Mercè; Blasco, Ana; Lozano, Rebeca; Ramchandani, Avinash; Beato, Carmen; de Castro, Eva Martínez; Espinosa, Javier; Martínez-García, Jerónimo; Ghanem, Ismael; Cubero, Jorge Hernando; Manrique, Isabel Aragón; Navalón, Francisco García; Sevillano, Elena; Manzano, Aránzazu; Virizuela, Juan; Garrido, Marcelo; Mondéjar, Rebeca; Arcusa, María Ángeles; Bonilla, Yaiza; Pérez, Quionia; Gallardo, Elena; del Carmen Soriano, Maria; Cardona, Mercè; Lasheras, Fernando Sánchez; Cruz, Juan Jesús; Ayala, Francisco

2016-01-01

Background: We sought to develop and externally validate a nomogram and web-based calculator to individually predict the development of serious complications in seemingly stable adult patients with solid tumours and episodes of febrile neutropenia (FN). Patients and methods: The data from the FINITE study (n=1133) and University of Salamanca Hospital (USH) FN registry (n=296) were used to develop and validate this tool. The main eligibility criterion was the presence of apparent clinical stability, defined as events without acute organ dysfunction, abnormal vital signs, or major infections. Discriminatory ability was measured as the concordance index and stratification into risk groups. Results: The rate of infection-related complications in the FINITE and USH series was 13.4% and 18.6%, respectively. The nomogram used the following covariates: Eastern Cooperative Group (ECOG) Performance Status ⩾2, chronic obstructive pulmonary disease, chronic cardiovascular disease, mucositis of grade ⩾2 (National Cancer Institute Common Toxicity Criteria), monocytes <200/mm3, and stress-induced hyperglycaemia. The nomogram predictions appeared to be well calibrated in both data sets (Hosmer–Lemeshow test, P>0.1). The concordance index was 0.855 and 0.831 in each series. Risk group stratification revealed a significant distinction in the proportion of complications. With a ⩾116-point cutoff, the nomogram yielded the following prognostic indices in the USH registry validation series: 66% sensitivity, 83% specificity, 3.88 positive likelihood ratio, 48% positive predictive value, and 91% negative predictive value. Conclusions: We have developed and externally validated a nomogram and web calculator to predict serious complications that can potentially impact decision-making in patients with seemingly stable FN. PMID:27187687

Clofibric acid degradation in UV254/H2O2 process: effect of temperature.

PubMed

Li, Wenzhen; Lu, Shuguang; Qiu, Zhaofu; Lin, Kuangfei

2010-04-15

The degradation of clofibric acid (CA) in UV(254)/H(2)O(2) process under three temperature ranges, i.e. T1 (9.0-11.5 degrees C), T2 (19.0-21.0 degrees C) and T3 (29.0-30.0 degrees C) was investigated. The effects of solution constituents including NO(3)(-) and HCO(3)(-) anions, and humic acid (HA) on CA degradation were evaluated in Milli-Q waters. CA degradation behaviors were simulated with the pseudo-first-order kinetic model and the apparent rate constant (k(ap)) and half-life time (t(1/2)) were calculated. The results showed that higher temperature would favor CA degradation, and CA degradation was taken place mostly by indirect oxidation through the formation of OH radicals in UV(254)/H(2)O(2) process. In addition, the effects of both NO(3)(-) and HCO(3)(-) anions at two selected concentrations (1.0x10(-3) and 0.1 mol L(-1)) and HA (20 mg L(-1)) on CA degradation were investigated. The results showed that HA had negative effect on CA degradation, and this effect was much more apparent under low temperature condition. On the other hand, the inhibitive effect on CA degradation at both lower and higher concentrations of bicarbonate was observed, and this inhibitive effect was much more apparent at higher bicarbonate concentration and lower temperature condition. While, at higher nitrate concentration the inhibitive effect on CA degradation under three temperature ranges was observed, and with the temperature increase this negative effect was apparently weakened. However, at lower nitrate concentration a slightly positive effect on CA degradation was found under T2 and T3 conditions. Moreover, when using a real wastewater treatment plant (WWTP) effluent spiked with CA over 99% of CA removal could be achieved under 30 degrees C within only 15 min compared with 40 and 80 min under 20 and 10 degrees C respectively, suggesting a significant promotion in CA degradation under higher temperature condition. Therefore, it can be concluded that temperature plays an important role in CA degradation in UV/H(2)O(2) process. 2009 Elsevier B.V. All rights reserved.

Near East/South Asia Report

DTIC Science & Technology

1985-02-02

the socialist countries of Eastern Europe, one must not, how- ever, let himself be deceived: the positive effects of this high state of con- juncture...indurative conditions and the structural rigidity of world economy do not fail to have a negative effect on the hydrocarbon market, with regard to...remains to be traveled, with the main goal to find the loopholes that offer new and effective expediencies. South-south cooperation is already

JPRS Report, Near East and South Asia, Pakistan

DTIC Science & Technology

1992-08-19

to study the changing conditions in Central Asia, point out the various ways in which Pakistan could establish relations and cooperation with these...and natural ties. Islam does not negate the existence of such ties; if one studies the various degrees of rights and responsibilities determined... studied the conditions and needs of the Central Asian Muslims and arranged to send any help needed as soon as possible. Practical measures to provide

JPRS Report Environmental Issues

DTIC Science & Technology

1990-08-28

127 157 The impact of the polluted air on the ecosystem in our country is increasing. This is also documented by the data on forests negatively...Dakar PANA 11 Aug] 11 CHINA Environmental Impact of Increased Fossil Fuel Burning Assessed [ZHONGGUO HUANJING BAO 22 Feb, 6 Mar] 13 Report on Laws...the INPE a brother institute of NASA. Talks on other means of cooperation were dis- cussed. One very interesting proposal is investigating the impact

Effects of meal size, clutch, and metabolism on the energy efficiencies of juvenile Burmese pythons, Python molurus.

PubMed

Cox, Christian L; Secor, Stephen M

2007-12-01

We explored meal size and clutch (i.e., genetic) effects on the relative proportion of ingested energy that is absorbed by the gut (apparent digestive efficiency), becomes available for metabolism and growth (apparent assimilation efficiency), and is used for growth (production efficiency) for juvenile Burmese pythons (Python molurus). Sibling pythons were fed rodent meals equaling 15%, 25%, and 35% of their body mass and individuals from five different clutches were fed rodent meals equaling 25% of their body mass. For each of 11-12 consecutive feeding trials, python body mass was recorded and feces and urate of each snake was collected, dried, and weighed. Energy contents of meals (mice and rats), feces, urate, and pythons were determined using bomb calorimetry. For siblings fed three different meal sizes, growth rate increased with larger meals, but there was no significant variation among the meal sizes for any of the calculated energy efficiencies. Among the three meal sizes, apparent digestive efficiency, apparent assimilation efficiency, and production efficiency averaged 91.0%, 84.7%, and 40.7%, respectively. In contrast, each of these energy efficiencies varied significantly among the five different clutches. Among these clutches production efficiency was negatively correlated with standard metabolic rate (SMR). Clutches containing individuals with low SMR were therefore able to allocate more of ingested energy into growth.

Dimerization of a Viral SET Protein Endows its Function

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

H Wei; M Zhou

Histone modifications are regarded as the most indispensible phenomena in epigenetics. Of these modifications, lysine methylation is of the greatest complexity and importance as site- and state-specific lysine methylation exerts a plethora of effects on chromatin structure and gene transcription. Notably, paramecium bursaria chlorella viruses encode a conserved SET domain methyltransferase, termed vSET, that functions to suppress host transcription by methylating histone H3 at lysine 27 (H3K27), a mark for eukaryotic gene silencing. Unlike mammalian lysine methyltransferases (KMTs), vSET functions only as a dimer, but the underlying mechanism has remained elusive. In this study, we demonstrate that dimeric vSET operatesmore » with negative cooperativity between the two active sites and engages in H3K27 methylation one site at a time. New atomic structures of vSET in the free form and a ternary complex with S-adenosyl homocysteine and a histone H3 peptide and biochemical analyses reveal the molecular origin for the negative cooperativity and explain the substrate specificity of H3K27 methyltransferases. Our study suggests a 'walking' mechanism, by which vSET acts all by itself to globally methylate host H3K27, which is accomplished by the mammalian EZH2 KMT only in the context of the Polycomb repressive complex.« less

Inequity responses of monkeys modified by effort

PubMed Central

van Wolkenten, Megan; Brosnan, Sarah F.; de Waal, Frans B. M.

2007-01-01

Without joint benefits, joint actions could never have evolved. Cooperative animals need to monitor closely how large a share they receive relative to their investment toward collective goals. This work documents the sensitivity to reward division in brown, or tufted, capuchin monkeys (Cebus apella). In addition to confirming previous results with a larger subject pool, this work rules out several alternative explanations and adds data on effort sensitivity. Thirteen adult monkeys exchanged tokens for rewards, showing negative reactions to receiving a less-favored reward than their partner. Because their negative reaction could not be attributed to the mere visibility of better rewards (greed hypothesis) nor to having received such rewards in the immediate past (frustration hypothesis), it must have been caused by seeing their partner obtain the better reward. Effort had a major effect in that by far the lowest level of performance in the entire study occurred in subjects required to expend a large effort while at the same time seeing their partner receive a better reward. It is unclear whether this effort–effect was based on comparisons with the partner, but it added significantly to the intensity of the inequity response. These effects are as expected if the inequity response evolved in the context of cooperative survival strategies. PMID:18000045

Inequity responses of monkeys modified by effort.

PubMed

van Wolkenten, Megan; Brosnan, Sarah F; de Waal, Frans B M

2007-11-20

Without joint benefits, joint actions could never have evolved. Cooperative animals need to monitor closely how large a share they receive relative to their investment toward collective goals. This work documents the sensitivity to reward division in brown, or tufted, capuchin monkeys (Cebus apella). In addition to confirming previous results with a larger subject pool, this work rules out several alternative explanations and adds data on effort sensitivity. Thirteen adult monkeys exchanged tokens for rewards, showing negative reactions to receiving a less-favored reward than their partner. Because their negative reaction could not be attributed to the mere visibility of better rewards (greed hypothesis) nor to having received such rewards in the immediate past (frustration hypothesis), it must have been caused by seeing their partner obtain the better reward. Effort had a major effect in that by far the lowest level of performance in the entire study occurred in subjects required to expend a large effort while at the same time seeing their partner receive a better reward. It is unclear whether this effort-effect was based on comparisons with the partner, but it added significantly to the intensity of the inequity response. These effects are as expected if the inequity response evolved in the context of cooperative survival strategies.

Ecological suicide in microbes.

PubMed

Ratzke, Christoph; Denk, Jonas; Gore, Jeff

2018-05-01

The growth and survival of organisms often depend on interactions between them. In many cases, these interactions are positive and caused by a cooperative modification of the environment. Examples are the cooperative breakdown of complex nutrients in microbes or the construction of elaborate architectures in social insects, in which the individual profits from the collective actions of her peers. However, organisms can similarly display negative interactions by changing the environment in ways that are detrimental for them, for example by resource depletion or the production of toxic byproducts. Here we find an extreme type of negative interactions, in which Paenibacillus sp. bacteria modify the environmental pH to such a degree that it leads to a rapid extinction of the whole population, a phenomenon that we call ecological suicide. Modification of the pH is more pronounced at higher population densities, and thus ecological suicide is more likely to occur with increasing bacterial density. Correspondingly, promoting bacterial growth can drive populations extinct whereas inhibiting bacterial growth by the addition of harmful substances-such as antibiotics-can rescue them. Moreover, ecological suicide can cause oscillatory dynamics, even in single-species populations. We found ecological suicide in a wide variety of microbes, suggesting that it could have an important role in microbial ecology and evolution.

The effects of perceived phenotypic racial stereotypicality and social identity threat on racial minorities' attitudes about police.

PubMed

Kahn, Kimberly Barsamian; Lee, J Katherine; Renauer, Brian; Henning, Kris R; Stewart, Greg

2017-01-01

This study examines the role of perceived phenotypic racial stereotypicality and race-based social identity threat on racial minorities' trust and cooperation with police. We hypothesize that in police interactions, racial minorities' phenotypic racial stereotypicality may increase race-based social identity threat, which will lead to distrust and decreased participation with police. Racial minorities (Blacks, Latinos, Native Americans, and multi-racials) and Whites from a representative random sample of city residents were surveyed about policing attitudes. A serial multiple mediation model confirmed that racial minorities' self-rated phenotypic racial stereotypicality indirectly affected future cooperation through social identity threat and trust. Due to the lack of negative group stereotypes in policing, the model did not hold for Whites. This study provides evidence that phenotypic stereotypicality influences racial minorities' psychological experiences interacting with police.

Dispensable, Redundant, Complementary, and Cooperative Roles of Dopamine, Octopamine, and Serotonin in Drosophila melanogaster

PubMed Central

Chen, Audrey; Ng, Fanny; Lebestky, Tim; Grygoruk, Anna; Djapri, Christine; Lawal, Hakeem O.; Zaveri, Harshul A.; Mehanzel, Filmon; Najibi, Rod; Seidman, Gabriel; Murphy, Niall P.; Kelly, Rachel L.; Ackerson, Larry C.; Maidment, Nigel T.; Jackson, F. Rob; Krantz, David E.

2013-01-01

To investigate the regulation of Drosophila melanogaster behavior by biogenic amines, we have exploited the broad requirement of the vesicular monoamine transporter (VMAT) for the vesicular storage and exocytotic release of all monoamine neurotransmitters. We used the Drosophila VMAT (dVMAT) null mutant to globally ablate exocytotic amine release and then restored DVMAT activity in either individual or multiple aminergic systems, using transgenic rescue techniques. We find that larval survival, larval locomotion, and female fertility rely predominantly on octopaminergic circuits with little apparent input from the vesicular release of serotonin or dopamine. In contrast, male courtship and fertility can be rescued by expressing DVMAT in octopaminergic or dopaminergic neurons, suggesting potentially redundant circuits. Rescue of major aspects of adult locomotion and startle behavior required octopamine, but a complementary role was observed for serotonin. Interestingly, adult circadian behavior could not be rescued by expression of DVMAT in a single subtype of aminergic neurons, but required at least two systems, suggesting the possibility of unexpected cooperative interactions. Further experiments using this model will help determine how multiple aminergic systems may contribute to the regulation of other behaviors. Our data also highlight potential differences between behaviors regulated by standard exocytotic release and those regulated by other mechanisms. PMID:23086220

Cooperative standing-horizontal-standing reentrant transition for numerous solid particles under external vibration.

PubMed

Takatori, Satoshi; Baba, Hikari; Ichino, Takatoshi; Shew, Chwen-Yang; Yoshikawa, Kenichi

2018-01-11

We report the collective behavior of numerous plastic bolt-like particles exhibiting one of two distinct states, either standing stationary or horizontal accompanied by tumbling motion, when placed on a horizontal plate undergoing sinusoidal vertical vibration. Experimentally, we prepared an initial state in which all of the particles were standing except for a single particle that was placed at the center of the plate. Under continuous vertical vibration, the initially horizontal particle triggers neighboring particles to fall over into a horizontal state through tumbling-induced collision, and this effect gradually spreads to all of the particles, i.e., the number of horizontal particles is increased. Interestingly, within a certain range of vibration intensity, almost all of the horizontal particles revert back to standing in association with the formation of apparent 2D hexagonal dense-packing. Thus, phase segregation between high and low densities, or crystalline and disperse domains, of standing particles is generated as a result of the reentrant transition. The essential features of such cooperative dynamics through the reentrant transition are elucidated with a simple kinetic model. We also demonstrate that an excitable wave with the reentrant transition is observed when particles are situated in a quasi-one-dimensional confinement on a vibrating plate.

Austrian Guideline for Geomechanical Design of Tunnels - Necessity for Cooperation between Geologists, Geotechnical and Civil Engineers

NASA Astrophysics Data System (ADS)

Schwarz, Ludwig; Eder, Stefan; Mattle, Bruno; Hammer, Helmut

Rising competitive pressure in the construction business, ever tighter schedules being set up by the clients and ongoing disputes between engineering geologists and civil engineers about the role of geotechnical engineers have - in the last few years - led to increasing discussions between engineers and geologists about the allocation of competences during the design process of underground structures. In the course of this debate, which is often polemic and anything but objective, important information is quite frequently lost - a development which may not only be to the disadvantage of the client but which may also do damage to the reputation of the professions involved. The design procedure of the new Austrian guideline for the geomechanical design of underground structures requires a close collaboration of geologists, geotechnical and civil engineers, yet without allocating competences. While preparing the tender documents for the first construction lot of the Northern feeder line of the Brenner base tunnel, the necessity of a close cooperation of the involved professions became apparent due to the complex geological situation encountered in the project area and the enormous amount of data available. Despite these difficult boundary conditions, the successful application of the guideline was last but not least the result of the joint efforts of the multidisciplinary design team.

Behavioral and neuronal determinants of negative reciprocity in the ultimatum game

PubMed Central

Hildebrandt, Andrea; Wilhelm, Oliver; Sommer, Werner

2016-01-01

The rejection of unfair offers in the ultimatum game (UG) indicates negative reciprocity. The model of strong reciprocity claims that negative reciprocity reflects prosociality because the rejecting individual is sacrificing resources in order to punish unfair behavior. However, a recent study found that the rejection rate of unfair offers is linked to assertiveness (status defense model). To pursue the question what drives negative reciprocity, the present study investigated individual differences in the rejection of unfair offers along with their behavioral and neuronal determinants. We measured fairness preferences and event-related potentials (ERP) in 200 healthy participants playing a computerized version of the UG with pictures of unfair and fair proposers. Structural equation modeling (SEM) on the behavioral data corroborated both the strong reciprocity and the status defense models of human cooperation: Not only more prosocial but also more assertive individuals were more likely to show negative reciprocity by rejecting unfair offers. Experimental ERP results confirmed the feedback negativity (FN) as a neural signature of fairness processing. Multilevel SEM of brain–behavior relationships revealed that negative reciprocity was significantly associated with individual differences in FN amplitudes in response to proposers. Our results confirm stable individual differences in fairness processing at the behavioral and neuronal level. PMID:27261490

Relationship between obesity, negative affect and basal heart rate in predicting heart rate reactivity to psychological stress among adolescents.

PubMed

Park, Andres E; Huynh, Pauline; Schell, Anne M; Baker, Laura A

2015-08-01

Reduced cardiovascular responses to psychological stressors have been found to be associated with both obesity and negative affect in adults, but have been less well studied in children and adolescent populations. These findings have most often been interpreted as reflecting reduced sympathetic nervous system response, perhaps associated with heightened baseline sympathetic activation among the obese and those manifesting negative affect. However, obesity and negative affect may themselves be correlated, raising the question of whether they both independently affect cardiovascular reactivity. The present study thus examined the separate effects of obesity and negative affect on both cardiovascular and skin conductance responses to stress (e.g., during a serial subtraction math task) in adolescents, while controlling for baseline levels of autonomic activity during rest. Both obesity and negative affect had independent and negative associations with cardiovascular reactivity, such that reduced stress responses were apparent for obese adolescents and those with high levels of negative affect. In contrast, neither obesity nor negative affect was related to skin conductance responses to stress, implicating specifically noradrenergic mechanisms rather than sympathetic mechanisms generally as being deficient. Moreover, baseline heart rate was unrelated to obesity in this sample, which suggests that heightened baseline of sympathetic activity is not necessary for the reduced cardiovascular reactivity to stress. Copyright © 2015 Elsevier B.V. All rights reserved.

Treatment-related toxicities in tumor-bearing cats treated with temozolomide alone or in combination with doxorubicin: a pilot assessment.

PubMed

Gagnon, Jerome; Dervisis, Nikolaos G; Kitchell, Barbara E

2012-08-01

A retrospective study assessing treatment-related toxicities in tumor-bearing cats treated with temozolomide (TMZ) alone or in combination with doxorubicin was conducted. TMZ was administered orally once a day for 5 days every 3 weeks at a dose of 20 mg/cat. Tumor response was evaluated with standard World Health Organization criteria and toxicity was monitored using veterinary co-operative oncology group-common terminology criteria for adverse events (VCOG--CTCAE) criteria. Ten tumor-bearing cats with various types of malignancies were treated with TMZ-based chemotherapy. Eight cats were evaluable for response. Two cats achieved a complete response, one achieved stable disease and five achieved a partial response. Four grade III and one grade IV hematological toxicities, and one grade IV gastrointestinal toxicity were observed. Four cats were euthanased as a result of apparent toxicity. One cat was euthanased as a result of severe and prolonged myelosuppression with fever. Three were euthanased for grade III pleural and pericardial effusions. Effusion was seen in cats treated with higher cumulative dose of TMZ (P = 0.0046). Planned additional case accrual was discontinued because of unacceptable levels of toxicity despite evidence of efficacy in some of the cats. Additional investigation is needed to elucidate this unexpected apparent cumulative toxicity.

Comparison of three commercially available fit-test methods.

PubMed

Janssen, Larry L; Luinenburg, D Michael; Mullins, Haskell E; Nelson, Thomas J

2002-01-01

American National Standards Institute (ANSI) standard Z88.10, Respirator Fit Testing Methods, includes criteria to evaluate new fit-tests. The standard allows generated aerosol, particle counting, or controlled negative pressure quantitative fit-tests to be used as the reference method to determine acceptability of a new test. This study examined (1) comparability of three Occupational Safety and Health Administration-accepted fit-test methods, all of which were validated using generated aerosol as the reference method; and (2) the effect of the reference method on the apparent performance of a fit-test method under evaluation. Sequential fit-tests were performed using the controlled negative pressure and particle counting quantitative fit-tests and the bitter aerosol qualitative fit-test. Of 75 fit-tests conducted with each method, the controlled negative pressure method identified 24 failures; bitter aerosol identified 22 failures; and the particle counting method identified 15 failures. The sensitivity of each method, that is, agreement with the reference method in identifying unacceptable fits, was calculated using each of the other two methods as the reference. None of the test methods met the ANSI sensitivity criterion of 0.95 or greater when compared with either of the other two methods. These results demonstrate that (1) the apparent performance of any fit-test depends on the reference method used, and (2) the fit-tests evaluated use different criteria to identify inadequately fitting respirators. Although "acceptable fit" cannot be defined in absolute terms at this time, the ability of existing fit-test methods to reject poor fits can be inferred from workplace protection factor studies.

Next-century ocean acidification and warming both reduce calcification rate, but only acidification alters skeletal morphology of reef-building coral Siderastrea siderea.

PubMed

Horvath, Kimmaree M; Castillo, Karl D; Armstrong, Pualani; Westfield, Isaac T; Courtney, Travis; Ries, Justin B

2016-07-29

Atmospheric pCO2 is predicted to rise from 400 to 900 ppm by year 2100, causing seawater temperature to increase by 1-4 °C and pH to decrease by 0.1-0.3. Sixty-day experiments were conducted to investigate the independent and combined impacts of acidification (pCO2 = 424-426, 888-940 ppm-v) and warming (T = 28, 32 °C) on calcification rate and skeletal morphology of the abundant and widespread Caribbean reef-building scleractinian coral Siderastrea siderea. Hierarchical linear mixed-effects modelling reveals that coral calcification rate was negatively impacted by both warming and acidification, with their combined effects yielding the most deleterious impact. Negative effects of warming (32 °C/424 ppm-v) and high-temperature acidification (32 °C/940 ppm-v) on calcification rate were apparent across both 30-day intervals of the experiment, while effects of low-temperature acidification (28 °C/888 ppm-v) were not apparent until the second 30-day interval-indicating delayed onset of acidification effects at lower temperatures. Notably, two measures of coral skeletal morphology-corallite height and corallite infilling-were negatively impacted by next-century acidification, but not by next-century warming. Therefore, while next-century ocean acidification and warming will reduce the rate at which corals build their skeletons, next-century acidification will also modify the morphology and, potentially, function of coral skeletons.

Next-century ocean acidification and warming both reduce calcification rate, but only acidification alters skeletal morphology of reef-building coral Siderastrea siderea

NASA Astrophysics Data System (ADS)

Horvath, Kimmaree M.; Castillo, Karl D.; Armstrong, Pualani; Westfield, Isaac T.; Courtney, Travis; Ries, Justin B.

2016-07-01

Atmospheric pCO2 is predicted to rise from 400 to 900 ppm by year 2100, causing seawater temperature to increase by 1-4 °C and pH to decrease by 0.1-0.3. Sixty-day experiments were conducted to investigate the independent and combined impacts of acidification (pCO2 = 424-426, 888-940 ppm-v) and warming (T = 28, 32 °C) on calcification rate and skeletal morphology of the abundant and widespread Caribbean reef-building scleractinian coral Siderastrea siderea. Hierarchical linear mixed-effects modelling reveals that coral calcification rate was negatively impacted by both warming and acidification, with their combined effects yielding the most deleterious impact. Negative effects of warming (32 °C/424 ppm-v) and high-temperature acidification (32 °C/940 ppm-v) on calcification rate were apparent across both 30-day intervals of the experiment, while effects of low-temperature acidification (28 °C/888 ppm-v) were not apparent until the second 30-day interval—indicating delayed onset of acidification effects at lower temperatures. Notably, two measures of coral skeletal morphology-corallite height and corallite infilling-were negatively impacted by next-century acidification, but not by next-century warming. Therefore, while next-century ocean acidification and warming will reduce the rate at which corals build their skeletons, next-century acidification will also modify the morphology and, potentially, function of coral skeletons.

High prevalence of exon 8 G533C mutation in apparently sporadic medullary thyroid carcinoma in Greece.

PubMed

Sarika, H L; Papathoma, A; Garofalaki, M; Vasileiou, V; Vlassopoulou, B; Anastasiou, E; Alevizaki, M

2012-12-01

Genetic screening for ret mutation has become routine practice in the evaluation of medullary thyroid carcinoma (MTC). Approximately 25% of these tumours are familial, and they occur as components of the multiple endocrine neoplasia type 2 syndromes (MEN 2A and 2B) or familial MTC. In familial cases, the majority of mutations are found in exons 10, 11, 13, 14 or 15 of the ret gene. A rare mutation involving exon 8 (G533C) has recently been reported in familial cases of MTC in Brazil and Greece; some of these cases were originally thought to be sporadic. The aim of this study was to re-evaluate a series of sporadic cases of MTC, with negative family history, and screen them for germline mutations in exon 8. Genomic DNA was extracted from peripheral lymphocytes in 129 unrelated individuals who had previously been characterized as 'sporadic' based on the negative family history and negative screening for ret gene mutations. Samples were analysed in Applied Biosystems 7500 real-time PCR and confirmed by sequencing. The G533C exon 8 mutation was identified in 10 of 129 patients with sporadic MTC. Asymptomatic gene carriers were subsequently identified in other family members. In our study, we found that 7·75% patients with apparently sporadic MTC do carry G533C mutation involving exon 8 of ret. We feel that there is now a need to include exon 8 mutation screening in all patients diagnosed as sporadic MTC, in Greece. © 2012 Blackwell Publishing Ltd.

Weak polyelectrolyte complexation driven by associative charging.

PubMed

Rathee, Vikramjit S; Zervoudakis, Aristotle J; Sidky, Hythem; Sikora, Benjamin J; Whitmer, Jonathan K

2018-03-21

Weak polyelectrolytes are relevant for a wide range of fields; in particular, they have been investigated as "smart" materials for chemical separations and drug delivery. The charges on weak polyelectrolytes are dynamic, causing polymer chains to adopt different equilibrium conformations even with relatively small changes to the surrounding environment. Currently, there exists no comprehensive picture of this behavior, particularly where polymer-polymer interactions have the potential to affect charging properties significantly. In this study, we elucidate the novel interplay between weak polyelectrolyte charging and complexation behavior through coupled molecular dynamics and Monte Carlo simulations. Specifically, we investigate a model of two equal-length and oppositely charging polymer chains in an implicit salt solution represented through Debye-Hückel interactions. The charging tendency of each chain, along with the salt concentration, is varied to determine the existence and extent of cooperativity in charging and complexation. Strong cooperation in the charging of these chains is observed at large Debye lengths, corresponding to low salt concentrations, while at lower Debye lengths (higher salt concentrations), the chains behave in apparent isolation. When the electrostatic coupling is long-ranged, we find that a highly charged chain strongly promotes the charging of its partner chain, even if the environment is unfavorable for an isolated version of that partner chain. Evidence of this phenomenon is supported by a drop in the potential energy of the system, which does not occur at the lower Debye lengths where both potential energies and charge fractions converge for all partner chain charging tendencies. The discovery of this cooperation will be helpful in developing "smart" drug delivery mechanisms by allowing for better predictions for the dissociation point of delivery complexes.

Weak polyelectrolyte complexation driven by associative charging

NASA Astrophysics Data System (ADS)

Rathee, Vikramjit S.; Zervoudakis, Aristotle J.; Sidky, Hythem; Sikora, Benjamin J.; Whitmer, Jonathan K.

2018-03-01

Weak polyelectrolytes are relevant for a wide range of fields; in particular, they have been investigated as "smart" materials for chemical separations and drug delivery. The charges on weak polyelectrolytes are dynamic, causing polymer chains to adopt different equilibrium conformations even with relatively small changes to the surrounding environment. Currently, there exists no comprehensive picture of this behavior, particularly where polymer-polymer interactions have the potential to affect charging properties significantly. In this study, we elucidate the novel interplay between weak polyelectrolyte charging and complexation behavior through coupled molecular dynamics and Monte Carlo simulations. Specifically, we investigate a model of two equal-length and oppositely charging polymer chains in an implicit salt solution represented through Debye-Hückel interactions. The charging tendency of each chain, along with the salt concentration, is varied to determine the existence and extent of cooperativity in charging and complexation. Strong cooperation in the charging of these chains is observed at large Debye lengths, corresponding to low salt concentrations, while at lower Debye lengths (higher salt concentrations), the chains behave in apparent isolation. When the electrostatic coupling is long-ranged, we find that a highly charged chain strongly promotes the charging of its partner chain, even if the environment is unfavorable for an isolated version of that partner chain. Evidence of this phenomenon is supported by a drop in the potential energy of the system, which does not occur at the lower Debye lengths where both potential energies and charge fractions converge for all partner chain charging tendencies. The discovery of this cooperation will be helpful in developing "smart" drug delivery mechanisms by allowing for better predictions for the dissociation point of delivery complexes.

Histidine residues in the Na+-coupled ascorbic acid transporter-2 (SVCT2) are central regulators of SVCT2 function, modulating pH sensitivity, transporter kinetics, Na+ cooperativity, conformational stability, and subcellular localization.

PubMed

Ormazabal, Valeska; Zuñiga, Felipe A; Escobar, Elizabeth; Aylwin, Carlos; Salas-Burgos, Alexis; Godoy, Alejandro; Reyes, Alejandro M; Vera, Juan Carlos; Rivas, Coralia I

2010-11-19

Na(+)-coupled ascorbic acid transporter-2 (SVCT2) activity is impaired at acid pH, but little is known about the molecular determinants that define the transporter pH sensitivity. SVCT2 contains six histidine residues in its primary sequence, three of which are exofacial in the transporter secondary structure model. We used site-directed mutagenesis and treatment with diethylpyrocarbonate to identify histidine residues responsible for SVCT2 pH sensitivity. We conclude that five histidine residues, His(109), His(203), His(206), His(269), and His(413), are central regulators of SVCT2 function, participating to different degrees in modulating pH sensitivity, transporter kinetics, Na(+) cooperativity, conformational stability, and subcellular localization. Our results are compatible with a model in which (i) a single exofacial histidine residue, His(413), localized in the exofacial loop IV that connects transmembrane helices VII-VIII defines the pH sensitivity of SVCT2 through a mechanism involving a marked attenuation of the activation by Na(+) and loss of Na(+) cooperativity, which leads to a decreased V(max) without altering the transport K(m); (ii) exofacial histidine residues His(203), His(206), and His(413) may be involved in maintaining a functional interaction between exofacial loops II and IV and influence the general folding of the transporter; (iii) histidines 203, 206, 269, and 413 affect the transporter kinetics by modulating the apparent transport K(m); and (iv) histidine 109, localized at the center of transmembrane helix I, might be fundamental for the interaction of SVCT2 with the transported substrate ascorbic acid. Thus, histidine residues are central regulators of SVCT2 function.

Notes from the field: wildlife rabies on an island free from canine rabies for 52 years--Taiwan, 2013.

PubMed

Wu, Hsiu; Chang, Su-San; Tsai, Hsiang-Jung; Wallace, Ryan M; Recuenco, Sergio E; Doty, Jeffrey B; Vora, Neil M; Chang, Feng-Yee

2014-02-28

Dog-to-dog transmission of rabies in Taiwan was eliminated in 1961; the island was considered canine rabies-free for 52 years. On July 16, 2013, three ferret-badgers (Melogale moschata) tested positive for rabies by fluorescent antibody testing at the Animal Health Research Institute, Council of Agriculture of Taiwan. This was the first time wild animals other than bats were tested. During 1999-2012, a total of 6,841 clinically healthy dogs and five apparently normal cats from shelters were tested and found negative for rabies. During 2009-2012, a total of 322 bats were tested and found negative for rabies.

Towards a biopsychological understanding of costly punishment: the role of basal cortisol.

PubMed

Pfattheicher, Stefan; Keller, Johannes

2014-01-01

Recent findings have documented a negative relation of basal endogenous cortisol and aggression after a provocation (i.e., reactive aggression) in humans. We build on these findings and investigated the relation of endogenous cortisol and reactive aggression in a social dilemma situation, that is, costly punishment of individuals who did not appropriately contribute to a common group project. Specifically, we predicted that basal cortisol is negatively related to costly punishment of uncooperative individuals. In the present study, basal cortisol was assessed prior to a public goods game with the option to punish other group members. In line with previous research on reactive aggression and basal cortisol, we found that basal cortisol was indeed negatively related to costly punishment. The findings are important for understanding costly punishment because this tendency has been documented as a possible basis for the evolution of cooperation.

Towards a Biopsychological Understanding of Costly Punishment: The Role of Basal Cortisol

PubMed Central

Pfattheicher, Stefan; Keller, Johannes

2014-01-01

Recent findings have documented a negative relation of basal endogenous cortisol and aggression after a provocation (i.e., reactive aggression) in humans. We build on these findings and investigated the relation of endogenous cortisol and reactive aggression in a social dilemma situation, that is, costly punishment of individuals who did not appropriately contribute to a common group project. Specifically, we predicted that basal cortisol is negatively related to costly punishment of uncooperative individuals. In the present study, basal cortisol was assessed prior to a public goods game with the option to punish other group members. In line with previous research on reactive aggression and basal cortisol, we found that basal cortisol was indeed negatively related to costly punishment. The findings are important for understanding costly punishment because this tendency has been documented as a possible basis for the evolution of cooperation. PMID:24416441

Rheological Behavior of Entangled Polystyrene-Polyhedral Oligosilsesquioxane (POSS) Copolymer

DTIC Science & Technology

2006-08-24

analysis. The effects of the presence of tethered POSS cages on the glass transition were studied using differential scanning...studies mainly focused on the effect of the long chain branches (LCBs) on the linear and non- linear rheological properties. How spherical cage -like...apparent activation energy increasing with increasing iBuPOSS loading. Like linear polymeric coil branches, the iBuPOSS cage plays a negative effect on

[Effects of disturbances of natural magnetic field of the Earth on melatonin production in patients with coronary heart disease].

PubMed

Rapoport, S I; Malinovskaia, N K; Oraevskií, V N; Komarov, F I; Nosovskií, A M; Vetterberg, L

1997-01-01

The obtained results clearly evidence for the influence of magnetic disturbances and storms on melatonin production in patients with ischemic heart disease. Improvement of 24-hour rhythm of melatonin secretion during the period of magnetic disturbances says in favour of this influence while an overall fall of melatonin production during magnetic disturbances and storms is an apparent negative factor.

Orbital Epstein-Barr Virus-Positive Polymorphic B-Cell Lymphoproliferative Disorder in an Apparently Immunocompetent Woman.

PubMed

Abendroth, Michael D; Bayerl, Michael G; Wilkinson, Michael J; Claxton, David F; Specht, Charles S

2017-12-01

We report a rare case of Epstein-Barr virus (EBV)-positive polymorphic B-cell lymphoproliferative disorder (LPD) involving the lacrimal gland of a 28-year-old, apparently immunocompetent woman. She presented with a chief complaint of orbital swelling and tenderness and was found to have a lesion involving the right lacrimal gland and distal superior and lateral rectus muscles. Histology of the lesion revealed histiocytes with pleomorphic nuclei, reactive lymphocytes, and scattered cells that resembled the Reed-Sternberg (R-S) cells of classical Hodgkin lymphoma. The R-S-like cells were positive for PAX5 and CD30 and negative for CD15, supporting a diagnosis of polymorphic B-cell LPD. In situ hybridization for EBV-encoded RNA demonstrated the presence of EBV. Most EBV-positive polymorphic B-cell LPDs are associated with immunodeficiency. However, the patient described is HIV-negative and has no identifiable defects in immunoglobulin levels or cell-mediated immunity. This raises the question of whether she has an underlying immunodeficiency resulting from subtle changes in T-cell physiology, or whether chronic EBV infection contributed to her immune dysfunction through an unclear mechanism. The orbital mass partially regressed with chemotherapy, and the patient has done well clinically with no recurrence of this EBV-LPD for over 2 years.

The correlation between apparent diffusion coefficient and tumor cellularity in patients: a meta-analysis.

PubMed

Chen, Lihua; Liu, Min; Bao, Jing; Xia, Yunbao; Zhang, Jiuquan; Zhang, Lin; Huang, Xuequan; Wang, Jian

2013-01-01

To perform a meta-analysis exploring the correlation between the apparent diffusion coefficient (ADC) and tumor cellularity in patients. We searched medical and scientific literature databases for studies discussing the correlation between the ADC and tumor cellularity in patients. Only studies that were published in English or Chinese prior to November 2012 were considered for inclusion. Summary correlation coefficient (r) values were extracted from each study, and 95% confidence intervals (CIs) were calculated. Sensitivity and subgroup analyses were performed to investigate potential heterogeneity. Of 189 studies, 28 were included in the meta-analysis, comprising 729 patients. The pooled r for all studies was -0.57 (95% CI: -0.62, -0.52), indicating notable heterogeneity (P<0.001). After the sensitivity analysis, two studies were excluded, and the pooled r was -0.61 (95% CI: -0.66, -0.56) and was not significantly heterogeneous (P = 0.127). Regarding tumor type subgroup analysis, there were sufficient data to support a strong negative correlation between the ADC and cellularity for brain tumors. There was no notable evidence of publication bias. There is a strong negative correlation between the ADC and tumor cellularity in patients, particularly in the brain. However, larger, prospective studies are warranted to validate these findings in other cancer types.

Cortisol Responsivity Differences in Children with Autism Spectrum Disorders During Free and Cooperative Play

PubMed Central

Schupp, Clayton; Simon, David; Corbett, Blythe A.

2013-01-01

Children with ASD demonstrate significant heterogeneity in their profiles of social interaction and stress responsivity. We evaluated behavior and stress response in 52 male children ages 8 to 12 in a naturalistic playground interaction paradigm involving a child with autism spectrum disorder, a typically developing peer, and a same-age confederate. Younger children in the ASD group engaged in 5.8 times more approach behavior and showed a lower cortisol response than their older peers. Those that verbally initiated with their peers also showed a higher cortisol response. Older children with ASD exhibited the highest stress responsivity, while younger children with ASD showed more willingness to approach others without apparent stress. Intervening early and often may contribute to improvements in social engagement in youth with ASD. PMID:23430177

Understanding tumor heterogeneity as functional compartments - superorganisms revisited

PubMed Central

2011-01-01

Compelling evidence broadens our understanding of tumors as highly heterogeneous populations derived from one common progenitor. In this review we portray various stages of tumorigenesis, tumor progression, self-seeding and metastasis in analogy to the superorganisms of insect societies to exemplify the highly complex architecture of a neoplasm as a system of functional "castes." Accordingly, we propose a model in which clonal expansion and cumulative acquisition of genetic alterations produce tumor compartments each equipped with distinct traits and thus distinct functions that cooperate to establish clinically apparent tumors. This functional compartment model also suggests mechanisms for the self-construction of tumor stem cell niches. Thus, thinking of a tumor as a superorganism will provide systemic insight into its functional compartmentalization and may even have clinical implications. PMID:21619636

Patients' perspectives on sexual history taking in Korea.

PubMed

Kim, Su Hyun; Lee, Young-Mee; Park, Jong Tae

2008-03-01

This study was conducted to assess patients' beliefs and attitudes towards physicians taking their sexual history during routine medical visits in Korea, where Confucianism is the core societal value. A survey questionnaire was administered to determine the patients' perspectives to sexual history taking, their actual experience of being asked about sexual issues by physicians, their belief in the importance of sexual history taking, their attitudes and cooperativeness towards each component of sexual history, and the effect of the physicians' age and gender on their comfort level during interview. 74.6% of respondents had never been asked about their sexual issues by physicians. Most patients showed a positive attitude and cooperativeness in general, although more than 25% had a negative attitude and were uncooperative with regards to certain components of sexual issues. Their comfort level to sexual history taking was not influenced by the physicians' age. However, female patients felt more comfortable discussing sexual issues with female physicians. Sexual history taking was often overlooked during routine medical visits in Korea, although patients showed a relatively positive and cooperative attitude. Women showed a greater preference for female physicians. Sexual history taking should be more facilitated in clinical practice and requires a deliberate approach and skill.

Global Low Frequency Protein Motions in Long-Range Allosteric Signaling

NASA Astrophysics Data System (ADS)

McLeish, Tom; Rogers, Thomas; Townsend, Philip; Burnell, David; Pohl, Ehmke; Wilson, Mark; Cann, Martin; Richards, Shane; Jones, Matthew

2015-03-01

We present a foundational theory for how allostery can occur as a function of low frequency dynamics without a change in protein structure. Elastic inhomogeneities allow entropic ``signalling at a distance.'' Remarkably, many globular proteins display just this class of elastic structure, in particular those that support allosteric binding of substrates (long-range co-operative effects between the binding sites of small molecules). Through multi-scale modelling of global normal modes we demonstrate negative co-operativity between the two cAMP ligands without change to the mean structure. Crucially, the value of the co-operativity is itself controlled by the interactions around a set of third allosteric ``control sites.'' The theory makes key experimental predictions, validated by analysis of variant proteins by a combination of structural biology and isothermal calorimetry. A quantitative description of allostery as a free energy landscape revealed a protein ``design space'' that identified the key inter- and intramolecular regulatory parameters that frame CRP/FNR family allostery. Furthermore, by analyzing naturally occurring CAP variants from diverse species, we demonstrate an evolutionary selection pressure to conserve residues crucial for allosteric control. The methodology establishes the means to engineer allosteric mechanisms that are driven by low frequency dynamics.

The neural dynamics underlying the interpersonal effects of emotional expression on decision making.

PubMed

Chen, Xuhai; Zheng, Tingting; Han, Lingzi; Chang, Yingchao; Luo, Yangmei

2017-04-20

Although numerous studies explore the effects of emotion on decision-making, the existing research has mainly focused on the influence of intrapersonal emotions, leaving the influence of one person's emotions on another's decisions underestimated. To specify how interpersonal emotions shape decision-making and delineate the underlying neural dynamics involved, the present study examined brain responses to utilitarian feedback combined with angry or happy faces in competitive and cooperative contexts. Behavioral results showed that participants responded slower following losses than wins when competitors express happiness but responded faster following losses than wins when cooperators express anger. Importantly, angry faces in competitive context reversed the differentiation pattern of feedback-related negativity (FRN) between losses and wins and diminished the difference between losses and wins on both P300 and theta power, but only diminished the difference on FRN between losses and wins in cooperative context. However, when partner displays happiness, losses versus wins elicited larger FRN and theta power in competitive context but smaller P300 in both contexts. These results suggest that interpersonal emotions shape decisions during both automatic motivational salience valuation (FRN) and conscious cognitive appraisal (P300) stages of processing, in which different emotional expressions exert interpersonal influence through different routes.

Reconciling spatial and temporal soil moisture effects on afternoon rainfall

PubMed Central

Guillod, Benoit P.; Orlowsky, Boris; Miralles, Diego G.; Teuling, Adriaan J.; Seneviratne, Sonia I.

2015-01-01

Soil moisture impacts on precipitation have been strongly debated. Recent observational evidence of afternoon rain falling preferentially over land parcels that are drier than the surrounding areas (negative spatial effect), contrasts with previous reports of a predominant positive temporal effect. However, whether spatial effects relating to soil moisture heterogeneity translate into similar temporal effects remains unknown. Here we show that afternoon precipitation events tend to occur during wet and heterogeneous soil moisture conditions, while being located over comparatively drier patches. Using remote-sensing data and a common analysis framework, spatial and temporal correlations with opposite signs are shown to coexist within the same region and data set. Positive temporal coupling might enhance precipitation persistence, while negative spatial coupling tends to regionally homogenize land surface conditions. Although the apparent positive temporal coupling does not necessarily imply a causal relationship, these results reconcile the notions of moisture recycling with local, spatially negative feedbacks. PMID:25740589

Agreeable fancy or disagreeable truth? Reconciling self-enhancement and self-verification.

PubMed

Swann, W B; Pelham, B W; Krull, D S

1989-11-01

Three studies asked why people sometimes seek positive feedback (self-enhance) and sometimes seek subjectively accurate feedback (self-verify). Consistent with self-enhancement theory, people with low self-esteem as well as those with high self-esteem indicated that they preferred feedback pertaining to their positive rather than negative self-views. Consistent with self-verification theory, the very people who sought favorable feedback pertaining to their positive self-conceptions sought unfavorable feedback pertaining to their negative self-views, regardless of their level of global self-esteem. Apparently, although all people prefer to seek feedback regarding their positive self-views, when they seek feedback regarding their negative self-views, they seek unfavorable feedback. Whether people self-enhance or self-verify thus seems to be determined by the positivity of the relevant self-conceptions rather than their level of self-esteem or the type of person they are.

The Effect of Metal-Semiconductor Contact on the Transient Photovoltaic Characteristic of HgCdTe PV Detector

PubMed Central

Cui, Haoyang; Xu, Yongpeng; Yang, Junjie; Tang, Naiyun; Tang, Zhong

2013-01-01

The transient photovoltaic (PV) characteristic of HgCdTe PV array is studied using an ultrafast laser. The photoresponse shows an apparent negative valley first, then it evolves into a positive peak. By employing a combined theoretical model of pn junction and Schottky potential, this photo-response polarity changing curves can be interpreted well. An obvious decreasing of ratio of negative valley to positive peak can be realized by limiting the illumination area of the array electrode. This shows that the photoelectric effect of Schottky barrier at metal-semiconductor (M/S) interface is suppressed, which will verify the correctness of the model. The characteristic parameters of transient photo-response induced from p-n junction and Schottky potential are extracted by fitting the response curve utilizing this model. It shows that the negative PV response induced by the Schottky barrier decreases the positive photovoltage generated by the pn junction. PMID:24194676

Perceptions of adolescents among teachers and social workers in the context of training programs in Hong Kong.

PubMed

Shek, Daniel T L; Chan, Chitat

2011-01-01

This article explores whether professionals working with young people hold a negative view on adolescents in Hong Kong. Data were collected from 1112 participants from 23 workshops in a 3-day training program of the Project P.A.T.H.S. in Hong Kong. In the workshop, there was a group activity inviting the participants to describe the characteristics of contemporary young people in Hong Kong. The findings showed that positive comments about adolescents were only half of the negative comments. The common themes that emerged from the negative comments included: "problematic self-conceptions", "do not have long-term life goals", "irresponsible", "materialistic", and "calculative". The common themes that emerged from the positive comments included: "good at learning new things", "energetic", and "creative". The themes apparently reflected sociocultural characteristics of the contemporary Hong Kong Society.

Spin-controlled negative magnetoresistance resulting from exchange interactions

NASA Astrophysics Data System (ADS)

Agrinskaya, N. V.; Kozub, V. I.; Mikhailin, N. Yu.; Shamshur, D. V.

2017-04-01

We studied conductivity of AlGaAs-GaAs quantum well structures (where centers of the wells were doped by Be) at temperatures higher than 4 K in magnetic fields up 10 T. Throughout all the temperature region considered the conductivity demonstrated activated behavior. At moderate magnetic fields 0.1 T < H < 1 T, we observed negative isotropic magnetoresistance, which was linear in magnetic field while for magnetic field normal with respect to the plane of the wells the magnetoresistance was positive at H > 2T. To the best of our knowledge, it was the first observation of linear negative magnetoresistance, which would be isotropic with respect to the direction of magnetic field. While the isotropic character of magnetoresistance apparently evidences role of spins, the existing theoretical considerations concerning spin effects in conductance fail to explain our experimental results. We believe that such a behavior can be attributed to spin effects supported by exchange interactions between localized states.

The effect of metal-semiconductor contact on the transient photovoltaic characteristic of HgCdTe PV detector.

PubMed

Cui, Haoyang; Xu, Yongpeng; Yang, Junjie; Tang, Naiyun; Tang, Zhong

2013-01-01

The transient photovoltaic (PV) characteristic of HgCdTe PV array is studied using an ultrafast laser. The photoresponse shows an apparent negative valley first, then it evolves into a positive peak. By employing a combined theoretical model of pn junction and Schottky potential, this photo-response polarity changing curves can be interpreted well. An obvious decreasing of ratio of negative valley to positive peak can be realized by limiting the illumination area of the array electrode. This shows that the photoelectric effect of Schottky barrier at metal-semiconductor (M/S) interface is suppressed, which will verify the correctness of the model. The characteristic parameters of transient photo-response induced from p-n junction and Schottky potential are extracted by fitting the response curve utilizing this model. It shows that the negative PV response induced by the Schottky barrier decreases the positive photovoltage generated by the pn junction.

Negative ion treatment increases positive emotional processing in seasonal affective disorder.

PubMed

Harmer, C J; Charles, M; McTavish, S; Favaron, E; Cowen, P J

2012-08-01

Antidepressant drug treatments increase the processing of positive compared to negative affective information early in treatment. Such effects have been hypothesized to play a key role in the development of later therapeutic responses to treatment. However, it is unknown whether these effects are a common mechanism of action for different treatment modalities. High-density negative ion (HDNI) treatment is an environmental manipulation that has efficacy in randomized clinical trials in seasonal affective disorder (SAD). The current study investigated whether a single session of HDNI treatment could reverse negative affective biases seen in seasonal depression using a battery of emotional processing tasks in a double-blind, placebo-controlled randomized study. Under placebo conditions, participants with seasonal mood disturbance showed reduced recognition of happy facial expressions, increased recognition memory for negative personality characteristics and increased vigilance to masked presentation of negative words in a dot-probe task compared to matched healthy controls. Negative ion treatment increased the recognition of positive compared to negative facial expression and improved vigilance to unmasked stimuli across participants with seasonal depression and healthy controls. Negative ion treatment also improved recognition memory for positive information in the SAD group alone. These effects were seen in the absence of changes in subjective state or mood. These results are consistent with the hypothesis that early change in emotional processing may be an important mechanism for treatment action in depression and suggest that these effects are also apparent with negative ion treatment in seasonal depression.

USSR Report World Economy and International Relations No. 10, October 1983.

DTIC Science & Technology

1984-01-12

offsets the negative consequences of such a situation. However, the socialist world is not at all indifferent to these developments in world economy...world—both with its allies and with the developing nations—was seen exclusively from the standpoint of a " global character of the Soviet threat...by the Group of 77 earlier (concerning the convening of global negotiations, the role of cooperation between developing countries in the

U.S.-Brazil Security Cooperation and the State Partnership Program

DTIC Science & Technology

2015-06-01

the recognition they deserve, and the U.S. ultimately risks losing its influence.29 As the former Secretary of State, Hillary Clinton believed...remains strong. Therefore, as the political situation needs to be mended, one of the best and most logical ways for doing so is through security...demonstrate its political discontent by stagnating the agreements. The negative trend that began in 2013, however, is finally beginning to turn positive

Pyromellitamide aggregates and their response to anion stimuli.

PubMed

Webb, James E A; Crossley, Maxwell J; Turner, Peter; Thordarson, Pall

2007-06-06

The N,N',N'',N'''-1,2,4,5-tetra(ethylhexanoate) pyromellitamide is found to be capable of both intermolecular aggregation and binding to small anions. It is synthesized by aminolysis of pyromellitic anhydride with ethanolamine, followed by a reaction with hexanoyl chloride. The single-crystal X-ray structure of the pyromellitamide shows that it forms one-dimensional columnar stacks through an intermolecular hydrogen-bonding network. It also forms self-assembled gels in nonpolar solvents, presumably by a hydrogen-bonding network similar to the solid-state structure as shown by IR and XRD studies. Aggregation by intermolecular hydrogen bonding of the pyromellitamide is also observed by NMR and IR in solution. Fitting of NMR dilution data for pyromellitamide in d6-acetone to a cooperative aggregation model gave KE=232 M-1 and positive cooperativity of aggregation (rho=0.22). The pyromellitamide binds to a range of small anions with the binding strength decreasing in the order chloride>acetate>bromide>nitrate approximately iodide. The data indicate that the pyromellitamide binds two anions and that it displays negative cooperativity. The intermolecular aggregation of the pyromellitamide can also be altered using small anion stimuli; anion addition to preformed self-assembled pyromellitamide gels causes their collapse. The kinetics of anion-induced gel collapse are qualitatively correlated to the binding affinities of the same anions in solution. The cooperative anion binding properties and the sensitivity of the self-assembled gels formed by pyromellitamide toward anions could be useful in the development of sensors and switching/releasing devices.

An efficient collaborative approach for black hole attack discovery and mitigating its impact in manet

NASA Astrophysics Data System (ADS)

Devipriya, K.; Ivy, B. Persis Urbana; Prabha, D.

2018-04-01

A mobile ad hoc network (MANET) is an assemblage of nodes composed of mobile devices coupled in various ways wirelessly which do not have any central administration. Each node in MANET cooperates in forwarding packets in the network. This type of collaboration incurs high cost but there exits nodes that declines to cooperate leading to selfish conduct of nodes which effects overall network performance. To discover the attacks caused by such nodes, a renowned mechanism using watchdog can be deployed. In infrastructure less network attack detection and reaction and high false positives, false negatives initiating black hole attack becomes major issue in watchdog. This paper put forward a collaborative approach for identifying such attacks in MANET. Through abstract analysis and extensive simulation of this approach, the detection time of misbehaved nodes is reduced and substantial enhancement in overhead and throughput is witnessed.

Binding site stoichiometry and the effects of phosphorylation on human α1 homomeric glycine receptors

PubMed Central

Gentet, Luc J; Clements, John D

2002-01-01

The kinetic properties of the human α1 homomeric glycine receptor were investigated. Receptors were expressed in HEK 293 cells, and glycine was applied to outside-out membrane patches with sub-millisecond solution exchange. The activation time course of the glycine response was used to investigate receptor stoichiometry. The unbinding of three strychnine molecules and the cooperative binding of two glycine molecules were required to activate the channel. The effects of phosphorylation on glycine receptor kinetics were investigated by pretreating cells with phosphorylators or with phosphatases. Phosphorylation accelerated desensitisation, but slowed deactivation and recovery from desensitisation. A chemical-kinetic model was developed that reproduced the experimental observations. The model suggests that only three binding sites on the glycine channel are functional, while the remaining two binding sites are ‘silent’, possibly due to strong negative cooperativity. PMID:12356883

DDT poisoning in a Cooper's hawk collected in 1980

USGS Publications Warehouse

Prouty, Richard M.; Pattee, Oliver H.; Schmeling, Shelia K.

1982-01-01

In April 1980, a Cooper's hawk (Accipiter cooperii) was found on the ground in Lakewood, Colorado, unable to fly and in convulsion. The bird died shortly thereafter. The hawk was packed in dry ice and shipped air express to the Fish and Wildlife Service, U. S. Department of the Interior, National Wildlife Health Laboratory, Madison, Wisconsin, for necropsy. Following necropsy, the brain, gastrointestinal tract, and remaining carcass except skin, feet, wings, liver, and kidney were packed in dry ice and shipped air express to the Patuxent Wildlife Research Center, Laurel, Maryland, for chemical residue analysis. Because the bird's behavior before death suggested some form of poisoning, the kidney was assayed for thallium, the liver for lead, and the gastrointestinal tract for strychnine, sodium fluoroacetate, and arsenic. When these assays proved negative, the bird was analyzed for organochlorine pesticides. Necropsy findings and pesticide residue analyses are reported here.

Trust and mindreading in adolescents: the moderating role of social value orientation.

PubMed

Derks, Jeffrey; Van Scheppingen, Manon A; Lee, Nikki C; Krabbendam, Lydia

2015-01-01

In adolescence, aspects of cognition that are required to deal with complex cooperation situations, such as mentalising and social value orientation, are still in development. In the Trust Game, cooperation may lead to better outcomes for both players, but can also lead to exploitation by the trustee. In the present study, we explore how mindreading, a crucial aspect of mentalising, and social value orientation (whether someone is prosocial or proself) are related to trust. In a group of 217 students (51% girls, Mage = 15.1) social value orientation, mindreading and trust (using the Trust Game) were measured. The result show that social value orientation moderates the relation between mindreading and trust. In the group of prosocials, we find no correlation between mindreading and trust. In the group of proselfs, mindreading is negatively correlated to trust, indicating that proselfs use their mentalising skills to assess that the trustee is likely to exploit them.

GENOPT 2016: Design of a generalization-based challenge in global optimization

NASA Astrophysics Data System (ADS)

Battiti, Roberto; Sergeyev, Yaroslav; Brunato, Mauro; Kvasov, Dmitri

2016-10-01

While comparing results on benchmark functions is a widely used practice to demonstrate the competitiveness of global optimization algorithms, fixed benchmarks can lead to a negative data mining process. To avoid this negative effect, the GENOPT contest benchmarks can be used which are based on randomized function generators, designed for scientific experiments, with fixed statistical characteristics but individual variation of the generated instances. The generators are available to participants for off-line tests and online tuning schemes, but the final competition is based on random seeds communicated in the last phase through a cooperative process. A brief presentation and discussion of the methods and results obtained in the framework of the GENOPT contest are given in this contribution.

The bovine immune response to Brucella abortus. II. Elimination of some sporadic serological reactions by chelation of divalent cations.

PubMed Central

Nielsen, K; Samagh, B S; Speckmann, G; Stemshorn, B

1979-01-01

The standard agglutination tests for detecting antibody to Brucella abortus were modified by addition of chelating agents (EDTA and EGTA) to the antigens. Approximately 80% of "singleton" agglutination test reactions, negative on the diagnostic complement fixation test, obtained with cattle sera were eliminated while no decrease in titer was apparent when sera from B. abortus infected or vaccinated cattle were tested. PMID:121242

Associations of group level popularity with observed behavior and influence in a dyadic context.

PubMed

Lansu, Tessa A M; Cillessen, Antonius H N

2015-12-01

This study examined the association between popularity in the peer group and adolescents' behavior in a dyadic context. After collecting peer nominations for popularity, 218 early adolescents (M(age) = 11.0 years) in 109 randomly composed same-sex dyads participated in a discussion task where they planned a party for their classroom. From digital recordings of the sessions, each participant's influence, involvement, skillful leadership, coercive resource control, submissiveness, positivity, and negativity were observed. Analyses with the actor-partner interdependence model (APIM) demonstrated that for girls high group level popularity was associated with a socially sensitive interaction style and influence in the dyadic context. For both boys and girls, the interaction partner's group level popularity negatively predicted their use of coercive resource control strategies and negative behavior in the dyad. For girls, in addition, the interaction partner's group level popularity also positively predicted their submissiveness and negatively predicted their task influence. These results indicate that, in particular for girls, adolescents' group level popularity plays an important role in the behavior of both peers in a cooperative dyadic context. Copyright © 2015 Elsevier Inc. All rights reserved.

Nickel-hydrogen battery with oxygen and electrolyte management features

DOEpatents

Sindorf, John F.

1991-10-22

A nickel-hydrogen battery or cell having one or more pressure vessels containing hydrogen gas and a plurality of cell-modules therein. Each cell-module includes a configuration of cooperatively associated oxygen and electrolyte mangement and component alignment features. A cell-module having electrolyte includes a negative electrode, a positive electrode adapted to facilitate oxygen diffusion, a separator disposed between the positive and negative electrodes for separating them and holding electrolyte for ionic conductivity, an absorber engaging the surface of the positive electrode facing away from the separator for providing electrolyte to the positive electrode, and a pair of surface-channeled diffusion screens for enclosing the positive and negative electrodes, absorber, and separator and for maintaining proper alignment of these components. The screens, formed in the shape of a pocket by intermittently sealing the edges together along as many as three sides, permit hydrogen gas to diffuse therethrough to the negative electrodes, and prevent the edges of the separator from swelling. Electrolyte is contained in the cell-module, absorbhed by the electrodes, the separator and the absorber.

Parallel search for conjunctions with stimuli in apparent motion.

PubMed

Casco, C; Ganis, G

1999-01-01

A series of experiments was conducted to determine whether apparent motion tends to follow the similarity rule (i.e. is attribute-specific) and to investigate the underlying mechanism. Stimulus duration thresholds were measured during a two-alternative forced-choice task in which observers detected either the location or the motion direction of target groups defined by the conjunction of size and orientation. Target element positions were randomly chosen within a nominally defined rectangular subregion of the display (target region). The target region was presented either statically (followed by a 250 ms duration mask) or dynamically, displaced by a small distance (18 min of arc) from frame to frame. In the motion display, the position of both target and background elements was changed randomly from frame to frame within the respective areas to abolish spatial correspondence over time. Stimulus duration thresholds were lower in the motion than in the static task, indicating that target detection in the dynamic condition does not rely on the explicit identification of target elements in each static frame. Increasing the distractor-to-target ratio was found to reduce detectability in the static, but not in the motion task. This indicates that the perceptual segregation of the target is effortless and parallel with motion but not with static displays. The pattern of results holds regardless of the task or search paradigm employed. The detectability in the motion condition can be improved by increasing the number of frames and/or by reducing the width of the target area. Furthermore, parallel search in the dynamic condition can be conducted with both short-range and long-range motion stimuli. Finally, apparent motion of conjunctions is insufficient on its own to support location decision and is disrupted by random visual noise. Overall, these findings show that (i) the mechanism underlying apparent motion is attribute-specific; (ii) the motion system mediates temporal integration of feature conjunctions before they are identified by the static system; and (iii) target detectability in these stimuli relies upon a nonattentive, cooperative, directionally selective motion mechanism that responds to high-level attributes (conjunction of size and orientation).