Microtubules are protein cylinders with functions in cell motility, signal sensing, cell organization, intracellular transport, and chromosome segregation. One of the key properties of microtubules is their dynamic architecture, allowing them to grow and shrink in length by adding or removing copies of their basic subunit, the heterodimer αβ‐tubulin. In higher eukaryotes, de novo assembly of microtubules from αβ‐tubulin is initiated by a 2 MDa multi‐subunit complex, the gamma‐tubulin ring complex (γ‐TuRC). For many years, the structure of the γ‐TuRC and (...) the function of its subunits remained enigmatic, although structural data from the much simpler yeast counterpart, the γ‐tubulin small complex (γ‐TuSC), were available. Two recent breakthroughs in the field, high‐resolution structural analysis and recombinant reconstitution of the complex, have revolutionized our knowledge about the architecture and function of the γ‐TuRC and will form the basis for addressing outstanding questions about biogenesis and regulation of this essential microtubule organizer. (shrink)

People often signal their membership in groups through their clothes, hairstyle, posture, and dialect. Most existing evolutionary models argue that markers label group members so individuals can preferentially interact with those in their group. Here we ask why people mark ethnic differences when interethnic interaction is routine, necessary, and peaceful. We asked research participants from three ethnic groups in southwestern Madagascar to sort photos of unfamiliar people by ethnicity, and by with whom they would prefer or not prefer to cooperate, (...) in a wage labor vignette. Results indicate that southwestern Malagasy reliably send and detect ethnic signals; they signal less in the marketplace, a primary site of interethnic coordination and cooperation; and they do not prefer co-ethnics as cooperation partners in novel circumstances. Results from a cultural knowledge survey and calculations of cultural FST suggest that these ethnic groups have relatively little cultural differentiation. We concur with Moya and Boyd that ethnicity is unlikely to be a singular social phenomenon. The current functions of ethnic divisions and marking may be different from those at the moment of ethnogenesis. Group identities may persist without group conflict or differentiation. (shrink)

Introduction Jan Abbink and Hans Vermeulen This volume consists of essays and studies by authors inspired by the work of Eric Wolf, a central figure in ...

1. Introduction The policy of deterrence, at least to avert nuclear war between the superpowers, has been a controversial one. The main controversy arises from the threat of each side to visit destruction on the other in response to an initial attack. This threat would seem irrational if carrying it out would lead to a nuclear holocaust – the worst outcome for both sides. Instead, it would seem better for the side attacked to suffer some destruction rather than to retaliate (...) in kind and, in the process of devastating the other side, seal its own doom in an all-out nuclear exchange. Yet, the superpowers persist in their adherence to deterrence, by which we mean a policy of threatening to retaliate to an attack by the other side in order to deter such an attack in the first place. To be sure, nuclear doctrine for implementing deterrence has evolved over the years, with such appellations as “massive retaliation,” “flexible response,” “mutual assured destruction”, and “counterforce” giving some flavor of the changes in United States strategic thinking. All such doctrines, however, entail some kind of response to a Soviet nuclear attack. They are operationalized in terms of preselected targets to be hit, depending on the perceived nature and magnitude of the attack. Thus, whether U.S. strategic policy at any time stresses a retaliatory attack on cities and industrial centers or on weapons systems and armed forces, the certainty of a response of some kind to an attack is not the issue. (shrink)

Cutting a cake, dividing up the property in an estate, determining the borders in an international dispute - such problems of fair division are ubiquitous. Fair Division treats all these problems and many more through a rigorous analysis of a variety of procedures for allocating goods, or deciding who wins on what issues, when there are disputes. Starting with an analysis of the well-known cake-cutting procedure, 'I cut, you choose', the authors show how it has been adapted in a number (...) of fields and then analyze fair-division procedures applicable to situations in which there are more than two parties, or there is more than one good to be divided. In particular they focus on procedures which provide 'envy-free' allocations, in which everybody thinks he or she has received the largest portion and hence does not envy anybody else. They also discuss the fairness of different auction and election procedures. (shrink)

Citing of previous publications is an important factor in knowledge development. Because of the great amount of publications available, only a selection of studies gets cited, for varying reasons. If the selection of citations is associated with study outcome this is called citation bias. We will study determinants of citation in a broader sense, including e.g. study design, journal impact factor or the funding source of the publication. As a case study we assess which factors drive citation in the human (...) literature on phthalates, specifically the metabolite mono phthalate. A systematic literature search identified all relevant publications on human health effect of MEHP. Data on potential determinants of citation were extracted in duplo. Specialized software was used to create a citation network, including all potential citation pathways. Random effect logistic regression was used to assess whether these determinants influence the likelihood of citation. 112 Publications on MEHP were identified, with 5684 potential citation pathways of which 551 were actual citations. Reporting of a harmful point estimate, journal impact factor, authority of the author, a male corresponding author, research performed in North America and self-citation were positively associated with the likelihood of being cited. In the literature on MEHP, citation is mostly driven by a number of factors that are not related to study outcome. Although the identified determinants do not necessarily give strong indications of bias, it shows selective use of published literature for a variety of reasons. (shrink)

We describe and analyse how large herbivores strongly diminished a woody vegetation, dominated by the unpalatable shrub Sambucus nigra L. and changed it into grassland. Density of woody species and cover of vegetation were measured in 1996, 2002 and 2012 in the grazed Oostvaardersplassen. In 2002 and 2012 we also measured density and cover in an ungrazed control site. In 2002 we measured intensity of browsing and bark loss of Sambucus shrubs in the grazed and control sites. In the grazed (...) site the density of Sambucus and Salix spp. declined significantly between 1996 and 2012, and large areas changed into grassland. In the control site the density of Sambucus increased significantly during this period, the density of Salix spp. did not change, and the vegetation consisted of a mixture of woody species and a field layer dominated by tall herbs. In 2002 and 2012 the percentages of dead Sambucus shrubs were significantly higher in the grazed site than in the control site. In 2002 the percentages of twigs browsed and ring barked stems of Sambucus shrubs were significantly higher in the grazed site than in the control site. Our results show that debarking caused mature Sambucus shrubs to die, but that heavy browsing may have helped this process. Our results also point to a significant neighbour effect on the break down of Sambucus, suggesting that Aggregational Resistance and Associational Palatability were both active. Essential conditions for the break down of this woody vegetation were the presence of large herbivores, the low ratio between the areas of summer and winter feeding habitats and the competition amongst herbivores. Browsing may have been responsible for seedling death, as seedlings were found only in the control site and not on the old and newly established grasslands in the grazed site. (shrink)

The concepts of omniscience and omnipotence are defined in 2 ? 2 ordinal games, and implications for the optimal play of these games, when one player is omniscient or omnipotent and the other player is aware of his omniscience or omnipotence, are derived. Intuitively, omniscience allows a player to predict the strategy choice of an opponent in advance of play, and omnipotence allows a player, after initial strategy choices are made, to continue to move after the other player is forced (...) to stop. Omniscience and its awareness by an opponent may hurt both players, but this problem can always be rectified if the other player is omniscient. This pathology can also be rectified if at least one of the two players is omnipotent, which can override the effects of omniscience. In some games, one player's omnipotence ? versus the other's ? helps him, whereas in other games the outcome induced does not depend on which player is omnipotent. Deducing whether a player is superior (omniscient or omnipotent) from the nature of his game playing alone raises several problems, however, suggesting the difficulty of devising tests for detecting superior ability in games. (shrink)

Drawing on ethical and legal frameworks in the Netherlands, the United States and France, we examine whether physicians are expected to inform patients about potentially relevant opportunities for expanded access to investigational drugs. While we found no definitive legal obligation, we argue that physicians have a moral obligation to discuss opportunities for expanded access with patients who have run out of treatment options to prevent inequality, to promote autonomy, and to achieve beneficence.

Suppose two players wish to divide a finite set of indivisible items, over which each distributes a specified number of points. Assuming the utility of a player’s bundle is the sum of the points it assigns to the items it contains, we analyze what divisions are fair. We show that if there is an envy-free (EF) allocation of the items, two other desirable properties—Pareto-optimality (PO) and Maximinality (MM)—can also be satisfied, rendering these three properties compatible. But there may be no (...) EF division, in which case some division must satisfy a modification of Bentham’s (1789/2017) “greatest satisfaction of the greatest number” property, called maximum Nash welfare (MNW), that satisfies PO. However, an MNF division may be neither MM nor EFX, which is a weaker form of EF. We conjecture that there is always an EFX allocation that satisfies MM, ensuring that an allocation is maximin, precisely the property that Rawls (1971/1999) championed. We discuss four broader philosophical implications of our more technical analysis. (shrink)

This paper analyzes criteria of fair division of a set of indivisible items among people whose revealed preferences are limited to rankings of the items and for whom no side payments are allowed. The criteria include refinements of Pareto optimality and envy-freeness as well as dominance-freeness, evenness of shares, and two criteria based on equally-spaced surrogate utilities, referred to as maxsum and equimax. Maxsum maximizes a measure of aggregate utility or welfare, whereas equimax lexicographically maximizes persons' utilities from smallest to (...) largest. The paper analyzes conflicts among the criteria along with possibilities and pitfalls of achieving fair division in a variety of circumstances. (shrink)

A cornerstone of game theory is backward induction, whereby players reason backward from the end of a game in extensive form to the beginning in order to determine what choices are rational at each stage of play. Truels, or three-person duels, are used to illustrate how the outcome can depend on (1) the evenness/oddness of the number of rounds (the parity problem) and (2) uncertainty about the endpoint of the game (the uncertainty problem). Since there is no known endpoint in (...) the latter case, an extension of the idea of backward induction is used to determine the possible outcomes. The parity problem highlights the lack of robustness of backward induction, but it poses no conflict between foundational principles. On the other hand, two conflicting views of the future underlie the uncertainty problem, depending on whether the number of rounds is bounded (the players invariably shoot from the start) or unbounded (they may all cooperate and never shoot, despite the fact that the truel will end with certainty and therefore be effectively bounded). Some real-life examples, in which destructive behavior sometimes occurred and sometimes did not, are used to illustrate these differences, and some ethical implications of the analysis are discussed. (shrink)

It is well known that Nash equilibria may not be Pareto-optimal; worse, a unique Nash equilibrium may be Pareto-dominated, as in Prisoners’ Dilemma. By contrast, we prove a previously conjectured result: every finite normal-form game of complete information and common knowledge has at least one Pareto-optimal nonmyopic equilibrium (NME) in pure strategies, which we define and illustrate. The outcome it gives, which depends on where play starts, may or may not coincide with that given by a Nash equilibrium. We use (...) some simple examples to illustrate properties of NMEs—for instance, that NME outcomes are usually, though not always, maximin—and seem likely to foster cooperation in many games. Other approaches for analyzing farsighted strategic behavior in games are compared with the NME analysis. (shrink)

Deterrence means threatening to retaliate against an attack in order to deter it in the first place. The central problem with a policy of deterrence is that the threat of retaliation may not be credible if retaliation leads to a worse outcome - perhaps a nuclear holocaust - than a side would suffer from absorbing a limited first strike and not retaliating. - The optimality of deterrence is analyzed by means of a Deterrence Game based on Chicken, in which each (...) player chooses a probability (or level) of preemption, and of retaliation if preempted. The Nash equilibria, or stable outcomes, in this game are compared with those in a Star Wars Game, in which the preemption and retaliation levels are constrained by the defensive capabilities of each side. Unlike threats in the Deterrence Game, which can always stabilize the cooperative outcome, mutual preemption emerges as an equilibrium in the Star Wars Game, underscoring the problem - particularly if defensive capabilities are unbalanced - that deterrence will be subverted by the development of Star Wars. (shrink)

Issues that arise in using game theory to model national security problems are discussed, including positing nation-states as players, assuming that their decision makers act rationally and possess complete information, and modeling certain conflicts as two-person games. A generic two-person game called the Conflict Game, which captures strategic features of such variable-sum games as Chicken and Prisoners'' Dilemma, is then analyzed. Unlike these classical games, however, the Conflict Game is a two-stage game in which each player can threaten to retaliate (...) — and carry out this threat in the second stage — if its opponent chose noncooperation in the first stage.Conditions for the existence of different pure-strategy Nash equilibria, or stable outcomes, are found, and these results are extended to situations in which the players can select mixed strategies (i.e., make probabilistic threats or choices). Although the Conflict Game sheds light on the rational foundations underlying arms races, nuclear deterrence, and other strategic situations, more detailed assumptions are required to tie this generic game to specific conflicts. (shrink)

1. Introduction The policy of deterrence, at least to avert nuclear war between the superpowers, has been a controversial one. The main controversy arises from the threat of each side to visit destruction on the other in response to an initial attack. This threat would seem irrational if carrying it out would lead to a nuclear holocaust – the worst outcome for both sides. Instead, it would seem better for the side attacked to suffer some destruction rather than to retaliate (...) in kind and, in the process of devastating the other side, seal its own doom in an all-out nuclear exchange. Yet, the superpowers persist in their adherence to deterrence, by which we mean a policy of threatening to retaliate to an attack by the other side in order to deter such an attack in the first place. To be sure, nuclear doctrine for implementing deterrence has evolved over the years, with such appellations as “massive retaliation,” “flexible response,” “mutual assured destruction”, and “counterforce” giving some flavor of the changes in United States strategic thinking. All such doctrines, however, entail some kind of response to a Soviet nuclear attack. They are operationalized in terms of preselected targets to be hit, depending on the perceived nature and magnitude of the attack. Thus, whether U.S. strategic policy at any time stresses a retaliatory attack on cities and industrial centers or on weapons systems and armed forces, the certainty of a response of some kind to an attack is not the issue. (shrink)

The Belief Game is a two-person, nonzero-sum game in which both players can do well [e.g., at (3, 4)] or badly [e.g., at (1,1)] simultaneously. The problem that occurs in the play of this game is that its rational outcome of (2, 3) is not only unappealing to both players, especially God, but also, paradoxically, there is an outcome, (3, 4), preferred by both players that is unattainable. Moreover, because God has a dominant strategy, His omniscience does not remedy the (...) situation, though - less plausibly - if man possessed this quality, and God were aware of it, (3, 4) would be attainable.How reasonable is it to use the device of a simple game to argue that nonrevelation by God, and nonbelief by man, are rational strategies? Like any model of a complex reality, the Belief Game abstracts a great deal from the problem that confronts the thoughtful agnostic asking the most profound of existential questions. Yet, to the degree that belief in God is seen as a personal question, conceptualized in terms of a possible relationship one might have with one's Creator, it seems appropriate to try to model this relationship as a game. The most difficult question to answer, I suppose, is, if God exists, what are His preferences in such a game?I have argued that He would first like to be believed, but at the same time not reveal Himself. These goals, in my opinion, are consistent with the role He assumes in many biblical stories, although this is not to say that the Bible offers the final word on philosophical and theological matters in the modern world. Nevertheless, it seems to me to be a logical place from which to start, and the clues it offers on God's preferences seem not contradicted by contemporary events.Of course, the Belief Game supposes that God not only has preferences but makes choices as well. To many people today - myself included - these choices are not apparent. But if He does make them, and in particular chooses not to reveal Himself, I think the Belief Game helps us to understand why nonrevelation is rational. Furthermore, it gives us insight into why, given this choice by God, our own reasons for believing in Him - in a game-theoretic context - may be rendered tenuous. (shrink)

To stimulate research and innovation (R&I), to contribute to the solution of societal challenges and to align R&I with societal values, the European Commission has launched the governance framework of Responsible Research and Innovation (RRI). RRI figures in many high-level EU policies as a means to promote smart growth, and a growing community of R&I practitioners from both the public and private sectors appears committed to it. Although debates on what RRI precisely entails have not reached closure yet, RRI provides (...) an interesting avenue to explore ways of making R&I more societally germane. While recognizing the usefulness of keeping critical reflection on RRI’s meaning alive, we suggest that to make the step from theorizing to implementation, RRI could benefit from a clearer conceptualization. This chapter presents the iterative trajectory in conceptualizing RRI followed as part of RRI Tools, one of a number of EC-funded research projects and support acts aimed at fleshing out what RRI can and should be, and the conceptualization of RRI that this led to. It suggests that RRI is best captured if in R&I governance attention is paid to the five p’s of Purpose, Products, Processes, Preconditions and People, and that further elaborations on the meaning of RRI should happen in dialogue with attempts at practicing RRI. (shrink)

BackgroundKnowledge development depends on an unbiased representation of the available evidence. Selective citation may distort this representation. Recently, some controversy emerged regarding the possible impact of swimming on childhood asthma, raising the question about the role of selective citation in this field. Our objective was to assess the occurrence and determinants of selective citation in scientific publications on the relationship between swimming in chlorinated pools and childhood asthma.MethodsWe identified scientific journal articles on this relationship via a systematic literature search. The (...) following factors were taken into account: study outcome (authors’ conclusion, data-based conclusion), other content-related article characteristics (article type, sample size, research quality, specificity), content-unrelated article characteristics (language, publication title, funding source, number of authors, number of affiliations, number of references, journal impact factor), author characteristics (gender, country, affiliation), and citation characteristics (time to citation, authority, self-citation). To assess the impact of these factors on citation, we performed a series of univariate and adjusted random-effects logistic regressions, with potential citation path as unit of analysis.ResultsThirty-six articles were identified in this network, consisting of 570 potential citation paths of which 191 (34%) were realized. There was strong evidence that articles with at least one author in common, cited each other more often than articles that had no common authors (odds ratio (OR) 5.2, 95% confidence interval (CI) 3.1–8.8). Similarly, the chance of being cited was higher for articles that were empirical rather than narrative (OR 4.2, CI 2.6–6.7), that reported a large sample size (OR 5.8, CI 2.9–11.6), and that were written by authors with a high authority within the network (OR 4.1, CI 2.1–8.0). Further, there was some evidence for citation bias: articles that confirmed the relation between swimming and asthma were cited more often (OR 1.8, CI 1.1–2.9), but this finding was not robust.ConclusionsThere is clear evidence of selective citation in this research field, but the evidence for citation bias is not very strong. (shrink)

This article examines deception possibilities for two players in simple three-person voting games. An example of one game vulnerable to (tacit) deception by two players is given and its implications discussed. The most unexpected findings of this study is that in those games vulnerable to deception by two players, the optimal strategy of one of them is always to announce his (true) preference order. Moreover, since the player whose optimal announcement is his true one is unable to induce a better (...) outcome for himself by misrepresenting his preference, while his partner can, this player will find that possessing a monopoly of information will not give him any special advantage. In fact, this analysis demonstrates that he may have incentives to share his information selectively with one or another of his opponents should he alone possess complete information at the outset. (shrink)

In this article three different types of loss aversion equilibria in bimatrix games are studied. Loss aversion equilibria are Nash equilibria of games where players are loss averse and where the reference points—points below which they consider payoffs to be losses—are endogenous to the equilibrium calculation. The first type is the fixed point loss aversion equilibrium, introduced in Shalev (2000; Int. J. Game Theory 29(2):269) under the name of ‘myopic loss aversion equilibrium.’ There, the players’ reference points depend on the (...) beliefs about their opponents’ strategies. The second type, the maximin loss aversion equilibrium, differs from the fixed point loss aversion equilibrium in that the reference points are only based on the carriers of the strategies, not on the exact probabilities. In the third type, the safety level loss aversion equilibrium, the reference points depend on the values of the own payoff matrices. Finally, a comparative statics analysis is carried out of all three equilibrium concepts in 2 × 2 bimatrix games. It is established when a player benefits from his opponent falsely believing that he is loss averse. (shrink)

The severe hereditary progeroid disorder Cockayne syndrome is a consequence of a defective transcription‐coupled repair (TCR) pathway. This special mode of DNA repair aids a RNA polymerase that is stalled by a DNA lesion in the template and ensures efficient DNA repair to permit resumption of transcription and prevent cell death. Although some key players in TCR, such as the Cockayne syndrome A (CSA) and B (CSB) proteins have been identified, the exact molecular mechanism still remains illusive. A recent report (...) provides new unexpected insights into TCR in yeast.1 The identification and characterisation of a novel protein co‐purifying with the yeast homologue of CSB (Rad26) imposes reassessment of our current understanding of TCR in yeast. What about humans? BioEssays 24:780–784, 2002. © 2002 Wiley Periodicals, Inc. (shrink)

A number of modern logic books give a misrepresentation of Mill's Methods as originally conceived by Mill. In this paper, I point out what I believe is a better presentation of Mill's Methods. This treatment is not only historically more accurate, but it also represents a better conceptual introduction to Mill's Methods in general.

The latter part of the 20th century is known for a surge in the so-called ‘genitive theologies’. Usually, a genitive theology has an ulterior motive, aiming at the transformation of a society or the promotion of sound politics and economy. In recent years, this trend culminated in public theology. The issue of religion with an ulterior motive was raised by Van de Beek in a seminal article focusing on theology without gaining anything from it as an answer to the surging (...) genitive theologies of the latter part of the 20th century and the public theologies of today. Taking into account Van de Beek’s critique against ‘religion with an ulterior motive’, this article explores the concept of the church as a moral agent in dialogue with Van de Beek. The central theoretical argument of this investigation is that Van de Beek’s ecclesiology is valuable when defining the role of the church as a moral agent. However, the perspective of the Kingdom of God concerning the church can enrich one’s views and can add value to his valid critique on public theology. (shrink)

The author of the acclaimed Gay Fiction Speaks brings us new interviews with twelve prominent gay writers who have emerged in the last decade. Hear Us Out demonstrates how in recent decades the canon of gay fiction has developed, diversified, and expanded its audience into the mainstream. Readers will recognize names like Michael Cunningham, whose Pulitzer Prize-winning novel The Hours inspired the hit movie; and others like Christopher Bram, Bernard Cooper, Stephen McCauley, and Matthew Stadler. These accounts explore the (...) vicissitudes of writing on gay male themes in fiction over the last thirty years--prejudices of the literary marketplace; social and political questions; the impact of AIDS; commonalities between gay male and lesbian fiction... and even some delectable bits of gossip. (shrink)

At least since the seminal work of the (US) National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research in the 1970s, a fundamental distinction between research and practice has underwritten both conceptual work in research ethics and regulations governing research involving human subjects. Notwithstanding its undoubted historical importance, I believe the distinction is problematic because it misrepresents clinical inquiry. In this essay, I aim to clarify the character of clinical inquiry by identifying crucial contextual constraints on (...) justification constitutive of clinical science. This analysis shows that, from an epistemological point of view, clinical research and clinical practice are not sharply distinct but intimately intertwined. This result is important in its own right—an enriched understanding of the epistemology of clinical research is valuable in and of itself. But this result is also important because it has profound implications for the ethics of human subjects research. (shrink)

As it is known, there is no rule satisfying Additivity in the complete domain of bankruptcy problems. This paper proposes a notion of partial Additivity in this context, to be called µ-additivity. We find that µ-additivity, together with two quite compelling axioms, anonymity and continuity, identify the Minimal Overlap rule, introduced by Neill (1982).

This commentary explores biological models of analogical and associative learning in support of Illusion 1 and Illusion 4 in D. Noble’s target article. The intent is to support Noble’s theses of emergent higher level functionality from lower level stochastic dynamics and his etiological claim that “there is no privileged level of causation” through a biosemiotic lens. Upon these arguments, a case for creative agency via higher-dimensional constraints will also be made in support of Noble’s claim that organismic behavior is actively (...) directed by an agent. (shrink)