Network formation under mutual consent and costly communication

We consider two different approaches to describe the formation of social networks under mutual consent and costly communication. First, we consider a network-based approach; in particular Jackson–Wolinsky’s concept of pairwise stability. Next, we discuss a non-cooperative game-theoretic approach, through a refinement of the Nash equilibria of Myerson’s consent game. This refinement, denoted as monadic stability, describes myopically forward looking behavior of the players. We show through an equivalence that the class of monadically stable networks is a strict subset of the class of pairwise stable networks that can be characterized fully by modifications of the properties defining pairwise stability.

Modelling the mechanical response of the reed-mouthpiece-lip system of a clarinet. Part II: A lumped model approximation

A non-linear lumped model of the reed-mouthpiece-lip system of a clarinet is formulated, in which the lumped parameters are derived from numerical experiments with a finite-difference simulation based on a distributed reed model. The effective stiffness per unit area is formulated as a function of the pressure signal driving the reed, in order to simulate the effects of the reed bending against the lay, and mass and damping terms are added as a first approximation to the dynamic behaviour of the reed. A discrete-time formulation is presented, and its response is compared to that of the distributed model. In addition, the lumped model is applied in the simulation of clarinet tones, enabling the analysis of the effects of using a pressure-dependent stiffness per unit area on sustained oscillations. The analysed effects and features are in qualitative agreement with players' experiences and experimental results obtained in prior studies.

China’s New Approach to CSR in Congo: Is the leverage turning to China?

China has been the world’s fastest growing economy in the past 30 years with its enterprises rapidly emerging and becoming leading players globally. In particular, the progressive integration into the international system has been spurred by China’s entry into the global trading regime of the World Trade Organization (WTO) in 2001. The 'go global' policy has been facilitating the rapidly growing engagement on the African continent of Chinese multinational companies (MNCs). As a promising tri-polar global economic entity, its growth of relations with Africa has been both unprecedented and impressive. As the Sino-Africa economic and business partnership surges forward, the matter of corporate social responsibility (CSR) is increasingly becoming an imperative ingredient for any successful business. It is noteworthy that responsible corporate citizens should take account of the impact of their investment on both economic and social arenas. However, it still remains uncertain what role Chinese MNCs have been playing in the continent’s sustainable development.
A Sino-Congo deal seems a positive way forward, accelerating the Democratic Republic of Congo’s (hereinafter referred to as Congo) regional economy, depressed due to years of war. Meanwhile, the escalating investment into Congo has raised controversies for its no-attachment policy, with increasing pressure imposed on China’s MNCs to take CSR more seriously. Particular concerns are focused on the multinationals’ inadequate environmental and human rights protection. The recent massive infrastructure investment is arguably perceived as a different interpretation of CSR, which has aroused a hot debate about whether China is heading for status as a responsible stakeholder in the international community. It is conducive to clarifying the paradoxical issue by addressing whether China’s recent approaches have the potential to facilitate CSR initiatives or hinder them in the long run.

The Effect of Risk Sensitivity on Collaborative New Product Development in a Supply Chain

The increasing risks and costs of new product development require firms to collaborate with their supply chain partners in product management. In this paper, a supply chain model is proposed with one risk-neutral supplier and one risk-averse manufacturer. The manufacturer has an opportunity to enhance demand by developing a new product, but both the actual demand for new product and the supplier’s wholesale price are uncertain. The supplier has an incentive to share risks of new product development via an advance commitment to wholesale price for its own profit maximization. The effects of the manufacturer’s risk sensitivity on the players’ optimal strategies are analyzed and the trade-off between innovation incentives and pricing flexibility is investigated from the perspective of the supplier. The results highlight the significant role of risk sensitivity in collaborative new product development, and it is found that the manufacturer’s innovation level and retail price are always decreasing in the risk sensitivity, and the supplier prefers commitment to wholesale price only when the risk sensitivity is below a certain threshold.

Coordination, Efficiency and Two-Sided Cheap Talk

We consider the Battle of the Sexes game with incomplete information and allow two-sided cheap talk before the game is played. We characterise the set of fully revealing symmetric cheap talk equilibria. The best fully revealing symmetric cheap talk equilibrium, when exists, has a desirable characteristic. When the players' types are different, it fully coordinates on the ex-post efficient pure Nash equilibrium. We also analyse the mediated communication equilibria of the game. We find the range of the prior for which this desirable equilibrium exists under unmediated and mediated communication processes.

A Framework for the Evaluation of Digital Musical Instruments

At the outset of a discussion of evaluating digital musical instruments, that is to say instruments whose sound generators are digital and separable though not necessarily separate from their control interfaces (Malloch, 2006), it is reasonable to ask what the term evaluation in this context really means. After all, there may be many perspectives from which to view the effectiveness or otherwise of the instruments we build. For most performers, performance on an instrument becomes a means of evaluating how well it functions in the context of live music making, and their measure of success is the response of the audience to their performance. Audiences evaluate performances on the basis of how engaged they feel they have been by what they have seen and heard. When questioned, they are likely to describe good performances as “exciting,” “skillful,” “musical.” Bad performances are “boring,” and those which are marred by technical malfunction are often dismissed out of hand. If performance is considered to be a valid means of evaluating a musical instrument, then it follows that, for the field of DMI design, a much broader definition of the term “evaluation” than that typically used in human-computer interaction (HCI) is required to reflect the fact that there are a number of stakeholders involved in the design and evaluation of DMIs. In addition to players and audiences, there are also composers, instrument builders, component manufacturers, and perhaps even customers, each of whom will have a different concept of what is meant by “evaluation.”

”Bricks vs. Clicks”: The impact of manufacturer encroachment with a dealer leasing and selling of durable goods

In durable goods markets, many brand name manufacturers, including IBM, HP, Epson, and Lenovo, have adopted dual-channel supply chains to market their products. There is scant literature, however, addressing the product durability and its impact on players’ optimal strategies in a dual-channel supply chain. To fill this void, we consider a two-period dual-channel model in which a manufacturer sells a durable product directly through both a manufacturer-owned e-channel and an independent dealer who adopts a mix of selling and leasing to consumers. Our results show that the manufacturer begins encroaching into the market in Period 1, but the dealer starts withdrawing from the retail channel in Period 2. Moreover, as the direct selling cost decreases, the equilibrium quantities and wholesale prices become quite angular and often nonmonotonic. Among other results, we find that both the dealer and the supply chain may benefit from the manufacturer’s encroachment. Our results also indicate that both the market structure and the nature of competition have an important impact on the player’s (dealer’s) optimal choice of leasing and selling.

Strategic behavior under partial cooperation

We investigate how a group of players might cooperate with each other within the setting of a non-cooperative game. We pursue two notions of partial cooperative equilibria that follow a modification of Nash's best response rationality rather than a core-like approach. Partial cooperative Nash equilibrium treats non-cooperative players and the coalition of cooperators symmetrically, while the notion of partial cooperative leadership equilibrium assumes that the group of cooperators has a first-mover advantage. We prove existence theorems for both types of equilibria. We look at three well-known applications under partial cooperation. In a game of voluntary provision of a public good we show that our two new equilibrium notions of partial cooperation coincide. In a modified Cournot oligopoly, we identify multiple equilibria of each type and show that a non-cooperator may have a higher payoff than a cooperator. In contrast, under partial cooperation in a symmetric Salop City game, a cooperator enjoys a higher return.

Risks and the financing of PPP: Perspectives from the financiers

Public private partnerships (PPP) are an established model for most governments internationally to provide infrastructure-based services, using private finance. Typically the public authority will sign a contract with a special purpose vehicle (SPV), which, because of the holistic nature of PPP, in turn sub-contracts the finance, design, construction, maintenance and soft services to companies that are often related to its shareholders. Thus there is a considerable network of linked organisations that together procure and provide the PPP project. While there is an increasing body of research that examines these PPP projects, much of it is interview or case study based so that the evidence is drawn from a small number of interviews or cases in specific sectors. It also focuses on the public sector procurer and the private sector contractor in the network of organisations. Although it has been recognised that the perceptions of the financiers may vary from those of other key PPP players there is much less research that focuses on the financiers. In this paper we report the results of a postal questionnaire survey, administered to 109 providers of senior debt and equity, from which the response rate was just less than 40%. We supplement these findings with a small number of illustrative quotes from interviewees, where the cited quote represents a commonly held view. We used SPSS and Nvivo to analyse the data. The findings show that when assessing PPPs financiers perceive a very wide range of risks as important, and that it is important to them that many of these risks are either insured or allocated to sub-contractors. When considering participating in PPPs, financiers agree that working with familiar partners on familiar projects and in familiar sectors is important, which may raise barriers to entry and undermine competitive processes.

Epidemiology of Adolescent Rugby Injuries: A Systematic Review

OBJECTIVE: Despite recent increases in the volume of research in professional rugby union, there is little consensus on the epidemiology of injury in adolescent players. We undertook a systematic review to determine the incidence, severity, and nature of injury in adolescent rugby union players.

DATA SOURCES: In April 2009, we performed a computerized literature search on PubMed, Embase, and Cochrane Controlled Trials Register (via Ovid). Population-specific and patient-specific search terms were combined in the form of MEDLINE subject headings and key words (wound$ and injur$, rugby, adolescent$). These were supplemented with related-citation searches on PubMed and bibliographic tracking of primary and review articles.

STUDY SELECTION: Prospective epidemiologic studies in adolescent rugby union players.

DATA SYNTHESIS: A total of 15 studies were included, and the data were analyzed descriptively. Two independent reviewers extracted key study characteristics regarding the incidence, severity, and nature of injuries and the methodologic design.

CONCLUSIONS: Wide variations existed in the injury definitions and data collection procedures. The incidence of injury necessitating medical attention varied with the definition, from 27.5 to 129.8 injuries per 1000 match hours. The incidence of time-loss injury (>7 days) ranged from 0.96 to 1.6 per 1000 playing hours and from 11.4/1000 match hours (>1 day) to 12-22/1000 match hours (missed games). The highest incidence of concussion was 3.3/1000 playing hours. No catastrophic injuries were reported. The head and neck, upper limb, and lower limb were all common sites of injury, and trends were noted toward greater time loss due to upper limb fractures or dislocations and knee ligament injuries. Increasing age, the early part of the playing season, and the tackle situation were most closely associated with injury. Future injury-surveillance studies in rugby union must follow consensus guidelines to facilitate interstudy comparisons and provide further clarification as to where injury-prevention strategies should be focused.

Qualifications, examinations and assessment: views and perspectives of students in the 14–19 phase on policy and practice

This paper brings to the forefront students’ views on one of the most significant aspects of education in the 14-19 phase, specifically the qualifications, examinations and assessment they experience. In this respect the paper foregrounds students as ‘policy actors’, they are significant players in the mediation of national qualification systems rather than just subjects in their implementation. Data from a national dataset of focus groups with 243 students from the 14-19 phase is presented. Key themes are highlighted relating to young people’s experiences of qualifications, examinations and assessment at this stage of education in a context of continuous initiatives and change as well as the impact of students being on the receiving end of qualification reform in situ which can be confusing, unsettling and ultimately detrimental to future success.

Perceiving and acting upon spaces in a VR rugby task: Expertise effects in affordance detection and task achievement

This study used a virtual simulated 3vs3 rugby task to investigate whether gaps opening in particular running channels promote different actions by the ball-carrier player and whether an effect of rugby expertise is verified. We manipulated emergent gaps in three different locations: gap1 in the participant’s own running channel, gap 2 in the 1st receiver's running channel, and gap3 in the 2nd receiver's running channel. Recreational, intermediate, professional and non-rugby players performed the task. They could i) run with the ball, ii) make a short pass, or iii) make a long pass. All actions were digitally recorded. Results revealed that the emergence of gaps in the defensive line with respect to the participant’s own position significantly influenced action selection. Namely, ‘run’ was most often the action performed in gap 1, ‘short pass’ in gap 2, and ‘long pass’ in gap 3 trials. Furthermore, a strong positive relationship between expertise and task achievement was found.

Metallo-aminopeptidase inhibitors

Aminopeptidases are enzymes that selectively hydrolyze an amino acid residue from the N-terminus of proteins and peptides. They are important for the proper functioning of prokaryotic and eukaryotic cells, but very often are central players in the devastating human diseases like cancer, malaria and diabetes. The largest aminopeptidase group include enzymes containing metal ion(s) in their active centers, which often determines the type of inhibitors that are the most suitable for them. Effective ligands mostly bind in a non-covalent mode by forming complexes with the metal ion(s). Here, we present several approaches for the design of inhibitors for metallo-aminopeptidases. The optimized structures should be considered as potential leads in the drug discovery process against endogenous and infectious diseases. Crown Copyright (C) 2010 Published by Elsevier Masson SAS. All rights reserved.

Evolutionary dynamics of the spatial Prisoner's Dilemma with self-inhibition

In this paper we study the influence of interventions on self-interactions in a spatial Prisoner's Dilemma on a two-dimensional grid with periodic boundary conditions and synchronous updating of the dynamics. We investigate two different types of self-interaction modifications. The first type (FSIP) is deterministic, effecting each self-interaction of a player by a constant factor, whereas the second type (PSIP) performs a probabilistic interventions. Both types of interventions lead to a reduction of the payoff of the players and, hence, represent inhibiting effects. We find that a constant but moderate reduction of self-interactions has a very beneficial effect on the evolution of cooperators in the population, whereas probabilistic interventions on self-interactions are in general counter productive for the coexistence of the two different strategies. (C) 2011 Elsevier Inc. All rights reserved.

Research ethics committees: values and power in higher education

The rise of research governance structures in universities has created huge disquiet amongst academic researchers. The unquestioning adoption of a medical model of ethical review based upon positivist methodological assumptions has created for many a mismatch between their own ongoing ethical research practice and the process of obtaining clearance from Research Ethics Committees (REC). This paper examines the issues that have contributed to dissatisfaction with the ethical review model that is prevalent within the modern university. Using examples from the authors’ own experiences, the dynamics of values, interests and power in research governance is examined from multiple perspectives including that of REC member and applicant; lecturer/student supervisor; researcher; and
university administrator. The paper reveals a rift between the values and objectives of the key players in research governance within the modern university and concludes by asking whether differences can be resolved so that a collaborative approach to ethical review may be incorporated into a renewed academic research culture. It is suggested that the alternative is increasing alienation from anything to do with ‘ethics’, with potentially serious consequences for the ethical standards of social research.