Cumulative frequency-dependent selective episodes allow for rapid morph cycles and rock-paper-scissors dynamics in species with overlapping generations.

Rock-paper-scissors (RPS) dynamics, which maintain genetic polymorphisms over time through negative frequency-dependent (FD) selection, can evolve in short-lived species with no generational overlap, where they produce rapid morph frequency cycles. However, most species have overlapping generations and thus, rapid RPS dynamics are thought to require stronger FD selection, the existence of which yet needs to be proved. Here, we experimentally demonstrate that two cumulative selective episodes, FD sexual selection reinforced by FD selection on offspring survival, generate sufficiently strong selection to generate rapid morph frequency cycles in the European common lizard Zootoca vivipara, a multi-annual species with major generational overlap. These findings show that the conditions required for the evolution of RPS games are fulfilled by almost all species exhibiting genetic polymorphisms and suggest that RPS games may be responsible for the maintenance of genetic diversity in a wide range of species.

Evolutionary branching in deme-structured populations.

Adaptive dynamics shows that a continuous trait under frequency dependent selection may first converge to a singular point followed by spontaneous transition from a unimodal trait distribution into a bimodal one, which is called "evolutionary branching". Here, we study evolutionary branching in a deme-structured population by constructing a quantitative genetic model for the trait variance dynamics, which allows us to obtain an analytic condition for evolutionary branching. This is first shown to agree with previous conditions for branching expressed in terms of relatedness between interacting individuals within demes and obtained from mutant-resident systems. We then show this branching condition can be markedly simplified when the evolving trait affect fecundity and/or survival, as opposed to affecting population structure, which would occur in the case of the evolution of dispersal. As an application of our model, we evaluate the threshold migration rate below which evolutionary branching cannot occur in a pairwise interaction game. This agrees very well with the individual-based simulation results.

Early Iron Age Pottery: A Quantitative Approach, Proceedings of the International Round Table organized by the Swiss School of Archaeology in Greece (Athens, November 28-30, 2008)

Quantitative approaches in ceramology are gaining ground in excavation reports, archaeological publications and thematic studies. Hence, a wide variety of methods are being used depending on the researchers' theoretical premise, the type of material which is examined, the context of discovery and the questions that are addressed. The round table that took place in Athens on November 2008 was intended to offer the participants the opportunity to present a selection of case studies on the basis of which methodological approaches were discussed. The aim was to define a set of guidelines for quantification that would prove to be of use to all researchers. Contents: 1) Introduction (Samuel Verdan); 2) Isthmia and beyond. How can quantification help the analysis of EIA sanctuary deposits? (Catherine Morgan); 3) Approaching aspects of cult practice and ethnicity in Early Iron Age Ephesos using quantitative analysis of a Protogeometric deposit from the Artemision (Michael Kerschner); 4) Development of a ceramic cultic assemblage: Analyzing pottery from Late Helladic IIIC through Late Geometric Kalapodi (Ivonne Kaiser, Laura-Concetta Rizzotto, Sara Strack); 5) 'Erfahrungsbericht' of application of different quantitative methods at Kalapodi (Sara Strack); 6) The Early Iron Age sanctuary at Olympia: counting sherds from the Pelopion excavations (1987-1996) (Birgitta Eder); 7) L'aire du pilier des Rhodiens à Delphes: Essai de quantification du mobilier (Jean-Marc Luce); 8) A new approach in ceramic statistical analyses: Pit 13 on Xeropolis at Lefkandi (David A. Mitchell, Irene S. Lemos); 9) Households and workshops at Early Iron Age Oropos: A quantitative approach of the fine, wheel-made pottery (Vicky Vlachou); 10) Counting sherds at Sindos: Pottery consumption and construction of identities in the Iron Age (Stefanos Gimatzidis); 11) Analyse quantitative du mobilier céramique des fouilles de Xombourgo à Ténos et le cas des supports de caisson (Jean-Sébastien Gros); 12) Defining a typology of pottery from Gortyn: The material from a pottery workshop pit, (Emanuela Santaniello); 13) Quantification of ceramics from Early Iron Age tombs (Antonis Kotsonas); 14) Quantitative analysis of the pottery from the Early Iron Age necropolis of Tsikalario on Naxos (Xenia Charalambidou); 15) Finding the Early Iron Age in field survey: Two case studies from Boeotia and Magnesia (Vladimir Stissi); 16) Pottery quantification: Some guidelines (Samuel Verdan)

Dispersal routes reconstruction and the minimum cost arborescence problem.

We show that the dispersal routes reconstruction problem can be stated as an instance of a graph theoretical problem known as the minimum cost arborescence problem, for which there exist efficient algorithms. Furthermore, we derive some theoretical results, in a simplified setting, on the possible optimal values that can be obtained for this problem. With this, we place the dispersal routes reconstruction problem on solid theoretical grounds, establishing it as a tractable problem that also lends itself to formal mathematical and computational analysis. Finally, we present an insightful example of how this framework can be applied to real data. We propose that our computational method can be used to define the most parsimonious dispersal (or invasion) scenarios, which can then be tested using complementary methods such as genetic analysis.

The role of reputation, punishment and their interplay in human cooperation

The problem of how cooperation can evolve between individuals or entities with conflicting interests is central to biology as many of the major evolutionary transitions, from the first replicating molecules to human societies, have required solving this problem. There are many routes to cooperation but humans seem to be distinct from other species as they have more complex and diverse mechanisms, often due to their higher cognitive skills, allowing them to reap the benefits from living in groups. Among those mechanisms, the use of reputation or past experience with others as well as sanctioning mechanisms both seem to be of major importance. They have often been considered separately but the interaction between the two might provide new insights as to how punishment could have appeared as a means to enforce cooperation in early humans. In this thesis, I firstly use theoretical approaches from evolutionary game theory to investigate the evolution of punishment and cooperation through a reputation system based on punitive actions, and compare the efficacy of this system, in terms of cooperation achieved, with one based on cooperative actions. On the other hand, I use empirical approaches from economics to test, in real life, predictions from theoretical models but also to explore further conditions such as environmental variation, constrained memory, or even the scale of competition between individuals. Both approaches have allowed contributing to the understanding of how these factors affect reputation and punishment use, and ultimately how cooperation is achieved.

Corporate responsibility in the postnational constellation : a multiple-case study

In my thesis I present the findings of a multiple-case study on the CSR approach of three multinational companies, applying Basu and Palazzo's (2008) CSR-character as a process model of sensemaking, Suchman's (1995) framework on legitimation strategies, and Habermas (1996) concept of deliberative democracy. The theoretical framework is based on the assumption of a postnational constellation (Habermas, 2001) which sends multinational companies onto a process of sensemaking (Weick, 1995) with regards to their responsibilities in a globalizing world. The major reason is that mainstream CSR-concepts are based on the assumption of a liberal market economy embedded in a nation state that do not fit the changing conditions for legitimation of corporate behavior in a globalizing world. For the purpose of this study, I primarily looked at two research questions: (i) How can the CSR approach of a multinational corporation be systematized empirically? (ii) What is the impact of the changing conditions in the postnational constellation on the CSR approach of the studied multinational corporations? For the analysis, I adopted a holistic approach (Patton, 1980), combining elements of a deductive and inductive theory building methodology (Eisenhardt, 1989b; Eisenhardt & Graebner, 2007; Glaser & Strauss, 1967; Van de Ven, 1992) and rigorous qualitative data analysis. Primary data was collected through 90 semi-structured interviews in two rounds with executives and managers in three multinational companies and their respective stakeholders. Raw data originating from interview tapes, field notes, and contact sheets was processed, stored, and managed using the software program QSR NVIVO 7. In the analysis, I applied qualitative methods to strengthen the interpretative part as well as quantitative methods to identify dominating dimensions and patterns. I found three different coping behaviors that provide insights into the corporate mindset. The results suggest that multinational corporations increasingly turn towards relational approaches of CSR to achieve moral legitimacy in formalized dialogical exchanges with their stakeholders since legitimacy can no longer be derived only from a national framework. I also looked at the degree to which they have reacted to the postnational constellation by the assumption of former state duties and the underlying reasoning. The findings indicate that CSR approaches become increasingly comprehensive through integrating political strategies that reflect the growing (self-) perception of multinational companies as political actors. Based on the results, I developed a model which relates the different dimensions of corporate responsibility to the discussion on deliberative democracy, global governance and social innovation to provide guidance for multinational companies in a postnational world. With my thesis, I contribute to management research by (i) delivering a comprehensive critique of the mainstream CSR-literature and (ii) filling the gap of thorough qualitative research on CSR in a globalizing world using the CSR-character as an empirical device, and (iii) to organizational studies by further advancing a deliberative view of the firm proposed by Scherer and Palazzo (2008).

Early Iron Age Pottery: A Quantitative Approach. Proceedings of the International Round Table organized by the Swiss School of Archaeology in Greece (Athens, Novembre 28-30, 2008).

Quantitative approaches in ceramology are gaining ground in excavation reports, archaeological publications and thematic studies. Hence, a wide variety of methods are being used depending on the researchers' theoretical premise, the type of material which is examined, the context of discovery and the questions that are addressed. The round table that took place in Athens on November 2008 was intended to offer the participants the opportunity to present a selection of case studies on the basis of which methodological approaches were discussed. The aim was to define a set of guidelines for quantification that would prove to be of use to all researchers. Contents: 1) Introduction (Samuel Verdan); 2) Isthmia and beyond. How can quantification help the analysis of EIA sanctuary deposits? (Catherine Morgan); 3) Approaching aspects of cult practice and ethnicity in Early Iron Age Ephesos using quantitative analysis of a Protogeometric deposit from the Artemision (Michael Kerschner); 4) Development of a ceramic cultic assemblage: Analyzing pottery from Late Helladic IIIC through Late Geometric Kalapodi (Ivonne Kaiser, Laura-Concetta Rizzotto, Sara Strack); 5) 'Erfahrungsbericht' of application of different quantitative methods at Kalapodi (Sara Strack); 6) The Early Iron Age sanctuary at Olympia: counting sherds from the Pelopion excavations (1987-1996) (Birgitta Eder); 7) L'aire du pilier des Rhodiens à Delphes: Essai de quantification du mobilier (Jean-Marc Luce); 8) A new approach in ceramic statistical analyses: Pit 13 on Xeropolis at Lefkandi (David A. Mitchell, Irene S. Lemos); 9) Households and workshops at Early Iron Age Oropos: A quantitative approach of the fine, wheel-made pottery (Vicky Vlachou); 10) Counting sherds at Sindos: Pottery consumption and construction of identities in the Iron Age (Stefanos Gimatzidis); 11) Analyse quantitative du mobilier céramique des fouilles de Xombourgo à Ténos et le cas des supports de caisson (Jean-Sébastien Gros); 12) Defining a typology of pottery from Gortyn: The material from a pottery workshop pit, (Emanuela Santaniello); 13) Quantification of ceramics from Early Iron Age tombs (Antonis Kotsonas); 14) Quantitative analysis of the pottery from the Early Iron Age necropolis of Tsikalario on Naxos (Xenia Charalambidou); 15) Finding the Early Iron Age in field survey: Two case studies from Boeotia and Magnesia (Vladimir Stissi); 16) Pottery quantification: Some guidelines (Samuel Verdan).

A cognitive hierarchy model of behavior in the action commitment game

We apply the cognitive hierarchy model of Camerer et al. (Q J Econ 119(3):861-898, 2004)-where players have different levels of reasoning-to Huck et al. (Games Econ Behav 38:240-264, 2002) discrete version of Hamilton and Slutsky (Games Econ Behav 2:29-46, 1990) action commitment game-a duopoly with endogenous timing of entry. We show that, for an empirically reasonable average number of thinking steps, the model rules out Stackelberg equilibria, generates Cournot outcomes including delay, and outcomes where the first mover commits to a quantity higher than Cournot but lower than Stackelberg leader. We show that a cognitive hierarchy model with quantal responses can explain the most important features of the experimental data on the action commitment game in (2002). In order to gauge the success of the model in fitting the data, we compare it to a noisy Nash model. We find that the cognitive hierarchy model with quantal responses fits the data better than the noisy Nash model.

Development and validation of a visual grading scale for assessing image quality of AP pelvis radiographic images.

OBJECTIVE: The aim of this article was to apply psychometric theory to develop and validate a visual grading scale for assessing the visual perception of digital image quality anteroposterior (AP) pelvis. METHODS: Psychometric theory was used to guide scale development. Seven phantom and seven cadaver images of visually and objectively predetermined quality were used to help assess scale reliability and validity. 151 volunteers scored phantom images, and 184 volunteers scored cadaver images. Factor analysis and Cronbach's alpha were used to assess scale validity and reliability. RESULTS: A 24-item scale was produced. Aggregated mean volunteer scores for each image correlated with the rank order of the visually and objectively predetermined image qualities. Scale items had good interitem correlation (X05;0.2) and high factor loadings (X05;0.3). Cronbach's alpha (reliability) revealed that the scale has acceptable levels of internal reliability for both phantom and cadaver images (αR01;=R01;0.8 and 0.9, respectively). Factor analysis suggested that the scale is multidimensional (assessing multiple quality themes). CONCLUSION: This study represents the first full development and validation of a visual image quality scale using psychometric theory. It is likely that this scale will have clinical, training and research applications. ADVANCES IN KNOWLEDGE: This article presents data to create and validate visual grading scales for radiographic examinations. The visual grading scale, for AP pelvis examinations, can act as a validated tool for future research, teaching and clinical evaluations of image quality.

Is sociality driven by the costs of dispersal or the benefits of philopatry? A role for kin-discrimination mechanisms.

The role of ecological constraints in promoting sociality is currently much debated. Using a direct-fitness approach, we show this role to depend on the kin-discrimination mechanisms underlying social interactions. Altruism cannot evolve under spatially based discrimination, unless ecological constraints prevent complete dispersal. Increasing constraints enhances both the proportion of philopatric (and thereby altruistic) individuals and the level of altruistic investments conceded in pairwise interactions. Familiarity-based discrimination, by contrast, allows philopatry and altruism to evolve at significant levels even in the absence of ecological constraints. Increasing constraints further enhances the proportion of philopatric (and thereby altruistic) individuals but not the level of altruism conceded. Ecological constraints are thus more likely to affect social evolution in species in which restricted cognitive abilities, large group size, and/or limited period of associative learning force investments to be made on the basis of spatial cues.

A musculoskeletal shoulder model based on pseudo-inverse and null-space optimization.

The goal of the present work was assess the feasibility of using a pseudo-inverse and null-space optimization approach in the modeling of the shoulder biomechanics. The method was applied to a simplified musculoskeletal shoulder model. The mechanical system consisted in the arm, and the external forces were the arm weight, 6 scapulo-humeral muscles and the reaction at the glenohumeral joint, which was considered as a spherical joint. The muscle wrapping was considered around the humeral head assumed spherical. The dynamical equations were solved in a Lagrangian approach. The mathematical redundancy of the mechanical system was solved in two steps: a pseudo-inverse optimization to minimize the square of the muscle stress and a null-space optimization to restrict the muscle force to physiological limits. Several movements were simulated. The mathematical and numerical aspects of the constrained redundancy problem were efficiently solved by the proposed method. The prediction of muscle moment arms was consistent with cadaveric measurements and the joint reaction force was consistent with in vivo measurements. This preliminary work demonstrated that the developed algorithm has a great potential for more complex musculoskeletal modeling of the shoulder joint. In particular it could be further applied to a non-spherical joint model, allowing for the natural translation of the humeral head in the glenoid fossa.

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Using analytical tools from game theory, we investigate the relevance of a series of hypotheses concerning natal dispersal, focusing in particular on the interaction between inbreeding and kin competition, as well as on the components of mating and social systems that are likely to interfere with these phenomena. A null model of pure kin competition avoidance predicts a balanced equilibrium in wich both sexes disperse equally. Inbreeding costs have the potential to destabilize the equilibrium, resulting in strongly sex-biased dispersal. This effect is mostly evident when the peculiarities of the mating system induce asymmetries in dispersal and/or inbreeding costs, or when kin cooperation counteracts kin competition. Inbreeding depression, however, is not the only possible cause for sex biases. The relevance of our results to empirical findings is dicussed and suggestions are made for further empirical or modelling work.

The average inter-crossing number of equilateral random walks and polygons

In this paper, we study the average inter-crossing number between two random walks and two random polygons in the three-dimensional space. The random walks and polygons in this paper are the so-called equilateral random walks and polygons in which each segment of the walk or polygon is of unit length. We show that the mean average inter-crossing number ICN between two equilateral random walks of the same length n is approximately linear in terms of n and we were able to determine the prefactor of the linear term, which is a = (3 In 2)/(8) approximate to 0.2599. In the case of two random polygons of length n, the mean average inter-crossing number ICN is also linear, but the prefactor of the linear term is different from that of the random walks. These approximations apply when the starting points of the random walks and polygons are of a distance p apart and p is small compared to n. We propose a fitting model that would capture the theoretical asymptotic behaviour of the mean average ICN for large values of p. Our simulation result shows that the model in fact works very well for the entire range of p. We also study the mean ICN between two equilateral random walks and polygons of different lengths. An interesting result is that even if one random walk (polygon) has a fixed length, the mean average ICN between the two random walks (polygons) would still approach infinity if the length of the other random walk (polygon) approached infinity. The data provided by our simulations match our theoretical predictions very well.

Assessment of youth-friendly health care: a systematic review of indicators drawn from young people's perspectives.

PURPOSE: To review the literature on young people's perspectives on health care with a view to defining domains and indicators of youth-friendly care. METHODS: Three bibliographic databases were searched to identify studies that purportedly measured young people's perspectives on health care. Each study was assessed to identify the constructs, domains, and indicators of adolescent-friendly health care. RESULTS: Twenty-two studies were identified: 15 used quantitative methods, six used qualitative methods and one used mixed methodology. Eight domains stood out as central to young people's positive experience of care. These were: accessibility of health care; staff attitude; communication; medical competency; guideline-driven care; age appropriate environments; youth involvement in health care; and health outcomes. Staff attitudes, which included notions of respect and friendliness, appeared universally applicable, whereas other domains, such as an appropriate environment including cleanliness, were more specific to particular contexts. CONCLUSION: These eight domains provide a practical framework for assessing how well services are engaging young people. Measures of youth-friendly health care should address universally applicable indicators of youth-friendly care and may benefit from additional questions that are specific to the local health setting.

Human cooperation based on punishment reputation.

The threat of punishment usually promotes cooperation. However, punishing itself is costly, rare in nonhuman animals, and humans who punish often finish with low payoffs in economic experiments. The evolution of punishment has therefore been unclear. Recent theoretical developments suggest that punishment has evolved in the context of reputation games. We tested this idea in a simple helping game with observers and with punishment and punishment reputation (experimentally controlling for other possible reputational effects). We show that punishers fully compensate their costs as they receive help more often. The more likely defection is punished within a group, the higher the level of within-group cooperation. These beneficial effects perish if the punishment reputation is removed. We conclude that reputation is key to the evolution of punishment.