Weak Dominance Research Articles

Performance and economic evaluation of the molecular detection of pathogens for patients with severe infections: the EVAMICA open-label, cluster-randomised, interventional crossover trial

PurposeMicrobiological diagnosis (MD) of infections remains insufficient. The resulting empirical antimicrobial therapy leads to multidrug resistance and inappropriate treatments. We therefore evaluated the cost-effectiveness of direct molecular detection of pathogens in blood for patients with severe sepsis (SES), febrile neutropenia (FN) and suspected infective endocarditis (SIE).MethodsPatients were enrolled in a multicentre, open-label, cluster-randomised crossover trial conducted during two consecutive periods, randomly assigned as control period (CP; standard diagnostic workup) or intervention period (IP; additional testing with LightCycler®SeptiFast). Multilevel models used to account for clustering were stratified by clinical setting (SES, FN, SIE).ResultsA total of 1416 patients (907 SES, 440 FN, 69 SIE) were evaluated for the primary endpoint (rate of blood MD). For SES patients, the MD rate was higher during IP than during CP [42.6% (198/465) vs. 28.1% (125/442), odds ratio (OR) 1.89, 95% confidence interval (CI) 1.43–2.50; P < 0.001], with an absolute increase of 14.5% (95% CI 8.4–20.7). A trend towards an association was observed for SIE [35.4% (17/48) vs. 9.5% (2/21); OR 6.22 (0.98–39.6)], but not for FN [32.1% (70/218) vs. 30.2% (67/222), P = 0.66]. Overall, turn-around time was shorter during IP than during CP (22.9 vs. 49.5 h, P < 0.001) and hospital costs were similar (median, mean ± SD: IP €14,826, €18,118 ± 17,775; CP €17,828, €18,653 ± 15,966). Bootstrap analysis of the incremental cost-effectiveness ratio showed weak dominance of intervention in SES patients.ConclusionAddition of molecular detection to standard care improves MD and thus efficiency of healthcare resource usage in patients with SES.ClinicalTrials.gov registration number: NCT00709358.

The role of multiplier bounds in fuzzy data envelopment analysis

The non-Archimedean epsilon $$\varepsilon $$ is commonly considered as a lower bound for the dual input weights and output weights in multiplier data envelopment analysis (DEA) models. The amount of $$\varepsilon $$ can be effectively used to differentiate between strongly and weakly efficient decision making units (DMUs). The problem of weak dominance particularly occurs when the reference set is fully or partially defined in terms of fuzzy numbers. In this paper, we propose a new four-step fuzzy DEA method to re-shape weakly efficient frontiers along with revisiting the efficiency score of DMUs in terms of perturbing the weakly efficient frontier. This approach eliminates the non-zero slacks in fuzzy DEA while keeping the strongly efficient frontiers unaltered. In comparing our proposed algorithm to an existing method in the recent literature we show three important flaws in their approach that our method addresses. Finally, we present a numerical example in banking with a combination of crisp and fuzzy data to illustrate the efficacy and advantages of the proposed approach.

Multi-objective particle swarm optimization based on global margin ranking

It is prevalent that the Pareto-based dominant framework is inefficient in non-dominated sorting because the performance sharply deteriorates when there are numerous weak dominance relations. In order to address this issue, the paper presents a novel ranking strategy called Global Margin Ranking (GMR) which deploys the position information of individuals in objective space to gain the margin of dominance throughout the population. The method not only considers the distribution of population, but also incorporates the associated information of individuals, without incurring user-defined parameters. Moreover, in view of the challenges faced by Multi-objective Particle Swarm Optimization (MOPSO) in selection of gBest and pBest, we present an innovative strategy for selecting gBest and pBest by integrating the GMR and the individual’s density information. We compare the GMR method with a variety of other ranking methods in terms of the distribution of ranks, the ranking landscape and convergence of the evolutionary process. The relatively extensive experimental results on some benchmark functions show that MOPSO/GMR performs better than those specialized MOEAs.

Lexicographic beliefs and assumption

Foundations for iterated admissibility (i.e., the iterated removal of weakly dominated strategies) need to confront a fundamental challenge. On the one hand, admissibility requires that a player consider every strategy of their opponents possible. On the other hand, reasoning that the opponents are rational requires ruling out certain strategies. Brandenburger, Friedenberg, Keisler's (BFK, Econometrica, 2008) foundations for iterated admissibility address this challenge with two ingredients: lexicographic beliefs and the concept of “assumption.” However, BFK restrict attention to lexicographic beliefs whose supports are essentially disjoint. This restriction does not have a compelling behavioral rationale, or a clear intuitive interpretation. At the same time, it plays a crucial role in BFK's foundations for iterated admissibility—specifically, in their analysis of assumption. We provide an alternate characterization of assumption, which applies to all lexicographic beliefs. We also characterize two variants of assumption, based on two extensions of ‘weak dominance’ to infinite state spaces. These notions of assumption coincide with BFK's notion when the state space is finite and lexicographic beliefs have disjoint support; but they are different in more general settings. Leveraging these characterization results, we show that disjoint supports do not play a role in the foundations for iterated admissibility.

Algorithms and Bounds for Overloaded Orthogonal Drawings

Orthogonal drawings are widely used for graph visualization due to their high clarity and ease of representation. But when it comes to high-degree and massive graphs, even orthogonal drawings have difficulties producing a clean and simple visualization. In this paper we present a technique called Overloaded Orthogonal Drawing that greatly improves the readability by proposing a new vertex placement and reframing the orthogonal edge routing approach. We first place the vertices on grid points following a relaxed version of dominance drawing, called weak dominance condition. Edge routing is implied automatically by the vertex coordinates. In order to simplify these drawings we use an overloading technique of the edges. All algorithms are simple and easy to implement and can be applied to directed acyclic graphs, planar, non-planar and undirected graphs. We also present bounds on the number of bends and the area. Overloaded orthogonal drawings present several interesting properties such as efficient visual edge confirmation as well as clarity of the drawing.

On the dispensable role of time in games of perfect information

In Aumann (Games Econ Behav 8(1):6–19, 1995, Games Econ Behav 23(1):97–105, 1998), time is assumed implicitly in the description of games of perfect information, and it is part of the epistemic distinction between ex-ante and ex-post knowledge. We show that ex-post knowledge in these papers can be expressed by ex-ante knowledge and therefore epistemically, time is irrelevant to the analysis. Furthermore, we show that material rationality by weak dominance and by expectation can be expressed in terms of the timeless strategic form of the game.

Causes, mechanisms, and consequences of contest competition among female mountain gorillas in Rwanda

Socioecological models predict that contest competition will arise when high quality foods can be usurped or monopolized, leading to more favorable energy balances and higher reproductive success for high-ranking females. Gorillas are interesting species for studying such predictions due to the variety of ecological conditions that they experience in different locations. Using data from 23 female mountain gorillas in 3 social groups in the Virunga Massif, we examined food characteristics that may influence contest competition (food site residence times [FSRT]), proximate mechanisms of such competition (aggression and avoidance), and potential consequences of competition (rank-related differences in energy intake rates, travel expenditures, and activity budgets). The average FSRT of each female was significantly correlated with dominance rank, which suggests that high-ranking females may have greater access to foods that are easier to usurp (as predicted with contest competition). High-ranking females were significantly more aggressive than low-ranking females, and both aggression and avoidance were significantly higher while feeding than during other activities. Contrary to predictions for contest competition, however, rank was not significantly correlated with energy intake rates nor with the proportion of time spent traveling versus feeding. Thus, we did not find any energetic benefits to explain why high-ranking females had significantly higher reproductive success in earlier studies. We propose several alternative explanations and discuss the potential complications of assessing contest competition in species with weak dominance relationships.

Sediment biomarker profiles trace organic matter input in the Pichavaram mangrove complex, southeastern India

The nature and distribution of lipid biomarkers (n-alkanes, n-alkanols, sterols and triterpenols) were investigated in five dated sediment cores from the Pichavaram mangrove–estuarine complex in order to: 1) identify the organic matter (OM) sources and its preservation and 2) trace recent changes associated with coastal processes and anthropogenic activities. The mangrove sediment extracts have higher biomarker concentration (22.6±13.3μg/g dry weight) than the estuarine extracts (6.42±4.92μg/g dry weight). Triterpenols are dominant biomarkers in both estuarine and mangrove sediments, and constitute >50% of the total lipid extracts. The presence of n-alkanols (n-C26,28,30) and abundance of phytosterols (stigmasterol and β-sitosterol) and triterpenols (taraxerol, β-amyrin, germanicol, and lupeol) indicate that mangrove vegetation is the primary source of sedimentary OM. The high abundance and unimodal distribution of the long-chain n-alkanes (mainly n-C25,27,29), and high values of Terrestrial Aquatic Ratio (TAR 2.4 to 41) and Carbon Preference Index (CPI>8) indicate dominance (and better preservation) of higher plant derived immature OM in mangrove sediments. In contrast, the weak dominance of high molecular weight n-alkanes, low CPI (0.75 to 0.90) and TAR (1.9 to 5.7) values, and the presence of high C27 and C28 sterols indicate that phytoplankton/algal derived OM is more pronounced in estuarine sediments. Diagenetic changes in sedimentary OM indicate that some of the lipid fractions are reactive, and as a result, they degrade more rapidly than bulk OM. These compounds follow first order decay kinetics, and concur with the downcore diagenetic changes in coastal areas. Resistance to degradation among the different lipid classes show the trend: n-alkane>sterol>triterpenol>n-alkanol. Finally, the study indicates that less freshwater discharge from the Coleroon River is causing a gradual change in mangrove vegetation. There is less input of OM derived from mangrove vegetation into recent sediments. Biomarker trends also indicate that less salt tolerant Rhizophora spp. are gradually replaced by more salt tolerant vegetation consisting of Sueda spp. and Aviccenia spp.

Perceived dominance in young heterosexual couples in relation to sex, context, and frequency of arguing.

This study used a theoretical framework derived from evolutionary biology and animal research to investigate dominance in heterosexual couples of young adults. We operationalized dominance as decision-making power and hypothesized that there would be agreement within couples as to who is dominant and who is subordinate, and that dominance would be consistent across different contexts. We also investigated variation in the sex of the dominant individual and in the strength of dominance across couples. Study participants were 140 young men and women (including 19 heterosexual couples in which both partners were tested), most of whom were college students. Overall couple dominance and dominance strength were assessed with a single-item self-report questionnaire. An additional 40-item questionnaire was used to investigate dominance and amount of arguing in different aspects of romantic relationships. Among the 19 couples, there was a significant agreement in the assessment of dominance between partners. Furthermore, among all study participants, assessments of couple dominance were consistent with perceived asymmetries in decision-making with regard to joint leisure activities, couple intimacy, and division of roles. Couples without clear dominance (egalitarian) generally argued less often than couples with strong or weak dominance. Men were more likely to be dominant than women. Overall, the principles underlying dominance in human heterosexual couples appear to be similar to those operating in nonhuman primates. Evolutionary and comparative theories of dominance could provide a valid framework for future studies of human couple dominance, in which both physiological and fitness correlates of dominance and subordination could be investigated.

Some Simple Tests of Rational Voting and Agenda Setting

This article analyzes election data that permit simple tests of rational voting and agenda setting. The voting test pertains to aggregate election results. The prediction is that when voters have single-peaked preferences, there will be more opposition to the second of two budget proposals that are voted on simultaneously. Unlike the standard binary choice setting, not all voters have weakly undominated voting strategies, but the game among the voters can be solved simply by iterative application of weak dominance. The agenda-setting prediction tested is that agenda setters should make one proposal rather than two when given the option. The data come from Oregon school district financial elections from 1980–83, years in which the rules for these elections were abruptly changed.

Comparative Expectations

I introduce a mathematical account of expectation based on a qualitative criterion of coherence for qualitative comparisons between gambles (or random quantities). The qualitative comparisons may be interpreted as an agent's comparative preference judgments over options or more directly as an agent's comparative expectation judgments over random quantities. The criterion of coherence is reminiscent of de Finetti's quantitative criterion of coherence for betting, yet it does not impose an Archimedean condition on an agent's comparative judgments, it does not require the binary relation reflecting an agent's comparative judgments to be reflexive, complete or even transitive, and it applies to an absolutely arbitrary collection of gambles, free of structural conditions (e.g., closure, measurability, etc.). Moreover, unlike de Finetti's criterion of coherence, the qualitative criterion respects the principle of weak dominance, a standard of rational decision making that obliges an agent to reject a gamble that is possibly worse and certainly no better than another gamble available for choice. Despite these weak assumptions, I establish a qualitative analogue of de Finetti's Fundamental Theorem of Prevision, from which it follows that any coherent system of comparative expectations can be extended to a weakly ordered coherent system of comparative expectations over any collection of gambles containing the initial set of gambles of interest. The extended weakly ordered coherent system of comparative expectations satisfies familiar additivity and scale invariance postulates (i.e., independence) when the extended collection forms a linear space. In the course of these developments, I recast de Finetti's quantitative account of coherent prevision in the qualitative framework adopted in this article. I show that comparative previsions satisfy qualitative analogues of de Finetti's famous bookmaking theorem and his Fundamental Theorem of Prevision. The results of this article complement those of another article (Pedersen, Strictly coherent preferences, no holds barred, Manuscript, 2013). I explain how those results entail that any coherent weakly ordered system of comparative expectations over a unital linear space can be represented by an expectation function taking values in a (possibly non-Archimedean) totally ordered field extension of the system of real numbers. The ordered field extension consists of formal power series in a single infinitesimal, a natural and economical representation that provides a relief map tracing numerical non-Archimedean features to qualitative non-Archimedean features.

Ex-post regret heuristics under private values (II): [formula omitted] games

When information is hardly available, the role of priors should be limited in robust game-theoretic predictions. We analyze a process of heuristics based on ex-post regret as a guide to understand how to play games of incomplete information with private values. While our dynamics has a strong component of inertia, its key is that with a small probability actions are modified in the direction of ex-post regrets. We apply stochastic stability to identify the strategies that will be used in the long run in 2×2 games (i.e., two players with two actions each). For a class of 2×2 games, which includes quasi-supermodular games satisfying “weak dominance”, the resulting theory predicts cautious behavior in the long run, as stochastically stable strategies are minimax regret equilibria. A minimax regret equilibrium is independent of the beliefs about the opponents’ types and actions (only the supports matter) and suggests a “safe way to play the game”.

Dominance rank differences in the energy intake and expenditure of female Bwindi mountain gorillas

Socioecological models predict that contest competition for clumped foods can lead to higher energy intake and lower energy expenditure for higher-ranking individuals. Here, we examine the relationships between dominance rank and energy intake and expenditure of female mountain gorillas in Bwindi Impenetrable National Park, Uganda (Gorilla beringei beringei). Bwindi gorillas have weak dominance relationships, feed on nonreproductive plant parts throughout the year, and consume fruit when it is seasonally available. We used behavioral observations on one group of gorillas and nutritional analysis of their major food items to calculate energy intake rates and estimated energy expenditure. Using linear mixed models, we found a significant positive relationship between dominance rank and energy intake rates, due to higher-ranking females having faster ingestion rates, rather than consuming foods with higher energy concentrations. Lower-ranking females did not spend significantly more time feeding to compensate for their lower energy intake rates. Lower-ranking females spent significantly more time traveling than higher-ranking females, leading to a negative relationship between dominance rank and energy expenditure. The combined results revealed a significant positive relationship between dominance rank and energy balance. Higher-ranking females did not spend longer feeding on fruit than lower-ranking ones, and the relationship between dominance rank and energy intake rates was not stronger when fruit was available. According to socioecological models, these results suggest that contest competition may be occurring with both fruit and nonreproductive plant parts, which would be consistent with growing evidence that nonreproductive plant parts can be contestable.

Theoretical approaches to lowest unique bid auctions

In this paper, we analyze a game called the lowest unique bid auction (LUBA). It is known that there is no closed form solution for the symmetric mixed strategy equilibria in LUBA. We propose two alternative approaches. We use weak dominance to identify upper bounds for players’ bids. Under symmetry, we provide a method to compute a mixed strategy equilibrium by utilizing the recursive structure of the winning chances of the bids under one assumption.

Competitiveness of destinations within the rural tourism cluster: Zlatar, Zlatibor

Cluster analysis is gaining increasing importance in the contemporary development of tourism. These are mostly areas that have similar tourist values. This paper presents the competitiveness of tourist destinations in the cluster of rural tourism Zlatar, Zlatibor, as defined in the Master Plan for Sustainable Development of Rural Tourism in Serbia. Having used AHP (Analytic Hierarchy Process) criteria pairs have been first compared, and then the alternatives (villages of Zlatar and Zlatibor). The seven criteria used in this paper are the following: factors and attractors, accessibility and infrastructure, accommodation facilities, unemployment, experience in rural tourism, proximity of the marketplace, and seasonality. The AHP method has been used to determine relations between the influence factors and the dominance of one factor in relation to another. It has been noted a relatively weak dominance of the villages of Zlatibor, by all criteria, except when it comes to unemployment, which is dominated by the villages of Zlatar.

Structural blueprint and ontogeny determine the adaptive value of the plastic response to competition in clonal plants: a modelling approach

Local competitive interactions strongly influence plant community dynamics. To maintain their performance under competition, clonal plants may plastically modify their network architecture to grow in the direction of least interference. The adaptive value of this plastic avoidance response may depend, however, on traits linked with the plant’s structural blueprint and ontogeny. We tested this hypothesis using virtual populations. We used an Individual Based Model to simulate competitive interactions among clones within a plant population. Clonal growth was studied under three competition intensities in plastic and non-plastic individuals. Plasticity buffered the negative impacts of competition at intermediate densities of competitors by promoting clone clumping. Success despite competition was promoted by traits linked with (1) the plant’s structural blueprint (weak apical dominance and sympodial growth) and (2) ontogenetic processes, with an increasing or a decreasing dependence of the elongation process on the branch generation level or length along the competition intensity gradient respectively. The adaptive value of the plastic avoidance response depended on the same traits. This response only modulated their importance for clone success. Our results show that structural blueprint and ontogeny can be primary filters of plasticity and can have strong implications for evolutionary ecology, as they may explain why clonal plants have developed many species-specific plastic avoidance behaviours.

On the Epistemic Foundation for Iterated Weak Dominance: An Analysis in a Logic of Individual and Collective attitudes

This paper proposes a logical framework for representing static and dynamic properties of different kinds of individual and collective attitudes. A complete axiomatization as well as a decidability result for the logic are given. The logic is applied to game theory by providing a formal analysis of the epistemic conditions of iterated deletion of weakly dominated strategies (IDWDS), or iterated weak dominance for short. The main difference between the analysis of the epistemic conditions of iterated weak dominance given in this paper and other analysis is that we use a semi-qualitative approach to uncertainty based on the notion of plausibility first introduced by Spohn, whereas other analysis are based on a quantitative representation of uncertainty in terms of probabilities.

Editorial Introduction to the Special Issue LOFT Sevilla

Journal of Philosophical Logic Volume 42 Number 6 December 2013 Special Issue on LOFT Sevilla Guest Editors: Giacomo Bonanno, Hans van Ditmarsch and Wiebe van der Hoek Editorial Introduction to the Special Issue LOFT Sevilla G. Bonanno I H. van Ditmarsch I W. van der Hoek 795 Computing Strong and Weak Permissions in Defeasible Logic G. Governatori I F. Olivieri I A. Rotolo I S. Scannapieco 799 Foundations of Everyday Practical Reasoning H. Lin 831 On the Epistemic Foundation for Iterated Weak Dominance: An Analysis in a Logic of Individual and Collective attitudes E. Lorini 863 Action Emulation between Canonical Models F. Sietsma I J. van Eijck 905

Plant genotypic diversity reduces the rate of consumer resource utilization.

While plant species diversity can reduce herbivore densities and herbivory, little is known regarding how plant genotypic diversity alters resource utilization by herbivores. Here, we show that an invasive folivore--the Japanese beetle (Popillia japonica)--increases 28 per cent in abundance, but consumes 24 per cent less foliage in genotypic polycultures compared with monocultures of the common evening primrose (Oenothera biennis). We found strong complementarity for reduced herbivore damage among plant genotypes growing in polycultures and a weak dominance effect of particularly resistant genotypes. Sequential feeding by P. japonica on different genotypes from polycultures resulted in reduced consumption compared with feeding on different plants of the same genotype from monocultures. Thus, diet mixing among plant genotypes reduced herbivore consumption efficiency. Despite positive complementarity driving an increase in fruit production in polycultures, we observed a trade-off between complementarity for increased plant productivity and resistance to herbivory, suggesting costs in the complementary use of resources by plant genotypes may manifest across trophic levels. These results elucidate mechanisms for how plant genotypic diversity simultaneously alters resource utilization by both producers and consumers, and show that population genotypic diversity can increase the resistance of a native plant to an invasive herbivore.

Weakly Stable Sets of NTU Game

In this paper, the definition of weak dominance is proposed for a NTU game and two new solution concepts of NTU games are introduced: the refined core and weakly stable set. The relationship is explored among the core, the weakly stable set and the refined core.