Games That End in a Bang or a Whimper

Using truels, or three-person duels, as an example, we show that how players perceive a multiple-round game will end can make a big difference in whether it ends non-cooperatively (producing a "bang") or just peters out (producing a "whimper"): 1. If the players view the number of rounds as bounded-reasonable, because the game must end in a finite number of rounds-they will shoot from the start. 2. If the players view the number of rounds as unbounded-reasonable, because the horizon of the game is infinite-then a cooperative equilibrium, involving no shooting, can also occur. Real- life examples are given of players with bounded and unbounded outlooks in truel- like situations. Unbounded outlooks encourage cooperative play, foster hope, and lead to more auspicious outcomes. These outcomes are facilitated by institutions that put no bounds on play-including reprisals-thereby allowing for a day of reckoning for those who violate established norms. Eschatological implications of the analysis, especially for thinking about the future and how it might end, are also discussed.TRUELS; BACKWARD INDUCTION; INFINITE-HORIZON GAMES; ESCHATOLOGY

Single-Peakedness and Disconnected Coalitions

Ordinally single-peaked preferences are distinguished from cardinally singlepeaked preferences, in which all players have a similar perception of distances in some one-dimensional ordering. While ordinal single-peakedness can lead to disconnected coalitions that have a "hole" in the ordering, cardinal single-peakedness precludes this possibility, based on two models of coalition formation: ¥ Fallback (FB): Players seek coalition partners by descending lower and lower in their preference rankings until a majority coalition forms. ¥ Build-Up (BU): Similar to FB, except that when nonmajority subcoalitions form, they fuse into composite players, whose positions are defined cardinally and who are treated as single players in the convergence process. FB better reflects the unconstrained, or nonmyopic, possibilities of coalition formation, whereas BU-because all subcoalition members must be included in any majority coalition that forms-restricts combinatorial possibilities and tends to produce less compact majority coalitions. The "strange bedfellows" frequently observed in legislative coalitions and military alliances suggest that even when players agree on, say, a left-right ordering, their perceptions of exactly where players stand in this ordering may differ substantially. If so, a player may be acceptable to a coalition but may not find every member in it acceptable, causing that player not to join and possibly creating a disconnected coalition.COALITION FORMATION; SINGLE-PEAKEDNESS; LEGISLATURES; ALLIANCES

Cooperative vs. Non-Cooperative Truels: Little Agreement, But Does That Matter?

It is well-known that non-cooperative and cooperative game theory may yield different solutions to games. These differences are particularly dramatic in the case of truels, or three-person duels, in which the players may fire sequentially or simultaneously, and the games may be one-round or n-round. Thus, it is never a Nash equilibrium for all players to hold their fire in any of these games, whereas in simultaneous one-round and n-round truels such cooperation, wherein everybody survives, is in both the alpha-core and beta-core. On the other hand, both cores may be empty, indicating a lack of stability, when the unique Nash equilibrium is one survivor. Conditions under which each approach seems most applicable are discussed. Although it might be desirable to subsume the two approaches within a unified framework, such unification seems unlikely since the two approaches are grounded in fundamentally different notions of stability.COOPERATIVE GAME; NON-COOPERATIVE GAME; TRUEL; NASH EQUILIBRIUM; CORE

Editorial: The ethics of publishing

Welcome to the second issue of The British Student Doctor. In this editorial, the Co-Editors-in-Chief of the journal outline the content of this issue and highlight the importance of publication ethics in the editorial and scientific process

Editorial: mental health and medical students

Welcome to Volume 2, Issue 1 of The British Student Doctor

The key elements of success and failure in the NZ kiwifruit industry

The study explores the nature and performance of the New Zealand kiwifruit industry from 1980 to 2006. As almost 94 per cent of kiwifruit produced in New Zealand is exported the focus of this study is on the export sector of the kiwifruit industry. Value chain theory is used to define the kiwifruit industry in New Zealand. The value chain links the key participants and organisations that ultimately bring kiwifruit to consumers. Therefore it incorporates the three main stages from the orchard to market - growing kiwifruit, post harvest operations, and exporting. The examination of the industry since 1980 can be separated into the following key focus areas: 1. changing market characteristics: production trends, target markets, changing consumer preferences and increasing competition. 2. operating environment: how different factors have changed to impact on the industry. 3. industry structure: changes at the firm and industry level in response to changing circumstances and environments. 4. conduct and performance: analysis of broad performance measures, extent of sharing of information, knowledge and resources within the industry, and the degree of interdependence along the value chain. In particular this study explores the kiwifruit industry’s current single desk seller structure – Zespri. It examines how it evolved by looking at the structural developments that preceded its existence and the factors that influenced its formation. It also looks at the recent consolidation amongst post-harvest operators and explores the factors that have bought about this change. It reviews how the industry has responded to changing market conditions by producing new products and how the role of marketing (i.e. branded products) has influenced export turnover.Funded by AGMARDT The Agricultural Marketing Research and Development Trus

A light‐activated acyl carrier protein 'trap' for intermediate capture in type II iterative polyketide biocatalysis

A discrete acyl carrier protein (ACP) bearing a photolabile nonhydrolysable carba(dethia) malonyl pantetheine cofactor was chemoenzymatically prepared and utilized for the trapping of biosynthetic polyketide intermediates following light activation. From the in vitro assembly of the polyketides SEK4 and SEK4b by the type II actinorhodin ‘minimal’ polyketide synthase (PKS), a range of putative ACP-bound diketides, tetraketides, pentaketides and hexaketides were identified and characterised by FT-ICR-MS, providing direct insights on active site accessibility and substrate processing for this enzyme class

Autopiquer - a robust and reliable peak detection algorithm for mass spectrometry

We present a simple algorithm for robust and unsupervised peak detection by determining a noise threshold in isotopically resolved mass spectrometry data. Solving this problem will greatly reduce the subjective and time consuming manual picking of mass spectral peaks and so will prove beneficial in many research applications. The Autopiquer approach uses autocorrelation to test for the presence of (isotopic) structure in overlapping windows across the spectrum. Within each window, a noise threshold is optimized to remove the most unstructured data whilst keeping as much of the (isotopic) structure as possible. This algorithm has been successfully demonstrated for both peak detection and spectral compression on data from many different classes of mass spectrometer and for different sample types and this approach should also be extendible to other types of data that contain regularly spaced discrete peaks

An investigation into the optimal number of distractors in single-best answer exams

In UK medical schools, five-option single-best answer (SBA) questions are the most widely accepted format of summative knowledge assessment. However, writing SBA questions with four effective incorrect options is difficult and time consuming, and consequently, many SBAs contain a high frequency of implausible distractors. Previous research has suggested that fewer than five-options could hence be used for assessment, without deterioration in quality. Despite an existing body of empirical research in this area however, evidence from undergraduate medical education is sparse. The study investigated the frequency of non-functioning distractors in a sample of 480 summative SBA questions at Cardiff University. Distractor functionality was analysed, and then various question models were tested to investigate the impact of reducing the number of distractors per question on examination difficulty, reliability, discrimination and pass rates. A survey questionnaire was additionally administered to 108 students (33 % response rate) to gain insight into their perceptions of these models. The simulation of various exam models revealed that, for four and three-option SBA models, pass rates, reliability, and mean item discrimination remained relatively constant. The average percentage mark however consistently increased by 1–3 % with the four and three-option models, respectively. The questionnaire survey revealed that the student body had mixed views towards the proposed format change. This study is one of the first to comprehensively investigate distractor performance in SBA examinations in undergraduate medical education. It provides evidence to suggest that using three-option SBA questions would maximise efficiency whilst maintaining, or possibly improving, psychometric quality, through allowing a greater number of questions per exam paper