Terrorist choice: a stochastic dominance and prospect theory analysis

The paper explores terrorist choice by applying two well-known theoretical frameworks: stochastic dominance and prospect theory. We analyse each pair of attack methods that can be formed from the RAND-MIPT database and the Global Terrorism Database (GTD). Instances of stochastic dominance are identified. Prospect theory orderings are computed. Attention is accorded to the identification of 'trigger points' and the circumstances that may lead to an increased likelihood that a terrorist will select an attack method associated with a higher expected number of fatalities, i.e. a potentially more damaging attack method

The deferral of attacks: SP/A theory as a model of terrorist choice when losses are inevitable

When a terrorist group’s aspirations far exceed the outcomes that can be expected to result from any of the available attack methods, an outcome below the terrorist group’s aspiration level is inevitable. A primary prediction of SP/A theory when applied to the study of terrorist behaviour is that when losses are inevitable the terrorist group will be risk averse and inclined to defer further action until expected outcomes improve, new attack method innovations are developed or the memory of the event that shaped aspirations has faded sufficiently that the aspiration level can be ‘reset’. This complements existing predictions of loss aversion and risk seeking behaviour over the domain of avoidable losses and provides a starting point for developing explanations for patterns of behaviour that are observed in the terrorism context, including pauses in violence, even during brutality contests, and time-lags between terrorist attacks

Terrorism, lightning and falling furniture

From time to time, opinion pieces appear in the media that point out that the risk of being harmed by terrorism is very low. This much is true, at least from an actuarial perspective. These opinion pieces are often accompanied by lists of other, usually absurd, ways that a person is more likely to die, including being struck by lightning or crushed by falling furniture. When asked, people do state a likelihood of being harmed by terrorism that is much greater than the actuarial odds. But risk perception is complex and to many people the actuarial odds of being killed by terrorism versus being killed by falling furniture do not adequately reflect the differences in the nature of risks from these two things. A discussion about risk perception and terrorism cannot start and end with the conclusion that people simply overestimate the risk. To do so would be to overlook the nuances of risk perception and decision-making under conditions of risk and uncertainty. An understanding of the complex ways in which risk perceptions are shaped is essential for those who would seek to accurately characterise, compare and regulate risks in the terrorism context

Terrorism watch lists, suspect ranking and decision-making biases

The large number of names on terrorism watch lists raises the problem of monitoring. Given the existing resource constraints and other logistical considerations, efficient and accurate ranking of individuals in terms of threat posed is of paramount importance. This process, however, may be impacted by reference points, diminishing sensitivity, loss aversion and other aspects of the human decision-making process that introduce biases. This paper explores the relevance of decision-making processes and biases to the specific task of ranking and monitoring individuals whose names have been placed on a terrorism watch list

Anticipated regret, terrorist behaviour & the presentation of the outcomes of attacks in the mainstream media and in terrorist group publications

Using the same executive function that allows him to plan a terrorist attack, the terrorist can consider the possibility that the outcomes of the attack will be imperfect in some way and that he will regret not having chosen a different type of attack or a different target. He can anticipate regret. In terrorism studies, a lot has been written about the relationship between the volume of media coverage accorded to terrorist attacks and incidences of terrorism. Regret theory, which is a framework for understanding how anticipated feelings of regret can influence the decision-making process, directs our attention beyond the debate over the volume of coverage in a general sense to the presentation of the outcomes of different terrorist actions. Our analysis generates suggestions for the direction that researchers might take in developing our understanding of the mechanisms by which mainstream media reporting and terrorist group publications shape terrorists' choices

Towards a Systems Approach in the Genetic Analysis of Archaea: Accelerating Mutant Construction and Phenotypic Analysis in Haloferax volcanii

With the availability of a genome sequence and increasingly sophisticated genetic tools, Haloferax volcanii is becoming a model for both Archaea and halophiles. In order for H. volcanii to reach a status equivalent to Escherichia coli, Bacillus subtilis, or Saccharomyces cerevisiae, a gene knockout collection needs to be constructed in order to identify the archaeal essential gene set and enable systematic phenotype screens. A streamlined gene-deletion protocol adapted for potential automation was implemented and used to generate 22 H. volcanii deletion strains and identify several potentially essential genes. These gene deletion mutants, generated in this and previous studies, were then analyzed in a high-throughput fashion to measure growth rates in different media and temperature conditions. We conclude that these high-throughput methods are suitable for a rapid investigation of an H. volcanii mutant library and suggest that they should form the basis of a larger genome-wide experiment

A Gateway platform for functional genomics in Haloferax volcanii

In part due to the existence of simple methods for its cultivation and genetic manipulation, Haloferax volcanii is a major archaeal model organism. It is the only archaeon for which the whole set of post-transcriptionally modified tRNAs has been sequenced, allowing for an in silico prediction of all RNA modification genes present in the organism. One approach to check these predictions experimentally is via the construction of targeted gene deletion mutants. Toward this goal, an integrative “Gateway vector” that allows gene deletion in H. volcanii uracil auxotrophs was constructed. The vector was used to delete three predicted tRNA modification genes: HVO_2001 (encoding an archaeal transglycosyl tranferase or arcTGT), which is involved in archeosine biosynthesis; HVO_2348 (encoding a newly discovered GTP cyclohydrolase I), which catalyzes the first step common to archaeosine and folate biosynthesis; and HVO_2736 (encoding a member of the COG1444 family), which is involved in N4-acetylcytidine (ac4C) formation. Preliminary phenotypic analysis of the deletion mutants was conducted, and confirmed all three predictions