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.

Evolutionary Requirements for Next-Generation Dataflow-Based FPGA System Design

The use of dataflow digital signal processing system modelling
and synthesis techniques has been a fruitful research theme for many years and has yielded many powerful rapid system synthesis and optimisation capabilities. However, recent years have seen the spectrum of languages and techniques splinter in an application specific manner, resulting in an ad-hoc design process which is increasingly dependent on the particular application under development. This poses a major problem for automated toolflows attempting to provide rapid system synthesis for a wide ranges of applications. By analysing a number of dataflow FPGA implementation case studies, this paper shows that despit ethis common traits may be found in current techniques, which fall largely into three classes. Further, it exposes limitations pertaining to their ability to adapt algorith models to implementations for different operating environments and target platforms.

Convergent evolutionary processes driven by foraging opportunity in two sympatric morph pairs of Arctic charr with contrasting post-glacial origins

The expression of two or more discrete phenotypes amongst individuals within a species (morphs) provides multiple modes upon which selection can act semi-independently, and thus may be an important stage in speciation. In the present study, we compared two sympatric morph systems aiming to address hypotheses related to their evolutionary origin. Arctic charr in sympatry in Loch Tay, Scotland, exhibit one of two discrete, alternative body size phenotypes at maturity (large or small body size). Arctic charr in Loch Awe segregate into two temporally segregated spawning groups (breeding in either spring or autumn). Mitochondrial DNA restriction fragment length polymorphism analysis showed that the morph pairs in both lakes comprise separate gene pools, although segregation of the Loch Awe morphs is more subtle than that of Loch Tay. We conclude that the Loch Awe morphs diverged in situ (within the lake), whereas Loch Tay morphs most likely arose through multiple invasions by different ancestral groups that segregated before post-glacial invasion (i.e. in allopatry). Both morph pairs showed clear trophic segregation between planktonic and benthic resources (measured by stable isotope analysis) but this was significantly less distinct in Loch Tay than in Loch Awe. By contrast, both inter-morph morphological and life-history differences were more subtle in Loch Awe than in Loch Tay. The strong ecological but relatively weak morphological and life-history divergence of the in situ derived morphs compared to morphs with allopatric origins indicates a strong link between early ecological and subsequent genetic divergence of sympatric origin emerging species pairs. The emergence of parallel specialisms despite distinct genetic origins of these morph pairs suggests that the effect of available foraging opportunities may be at least as important as genetic origin in structuring sympatric divergence in post-glacial fishes with high levels of phenotypic plasticity. (c) 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, , .

Asymmetric information without common priors: an indirect evolutionary analysis of quantity competition

The common prior assumption justifies private beliefs as posterior probabilities when updating a common prior based on individual information. We dispose of the common prior assumption for a homogeneous oligopoly market with uncertain costs and firms entertaining arbitrary priors about other firms' cost-type. We show that true prior beliefs can not be evolutionarily stable when truly expected profit measures (reproductive) success.

The effects and side-effects of statistics education: Psychology students’ (mis-)conceptions of probability

In three studies we looked at two typical misconceptions of probability: the representativeness heuristic, and the equiprobability bias. The literature on statistics education predicts that some typical errors and biases (e.g., the equiprobability bias) increase with education, whereas others decrease. This is in contrast with reasoning theorists’ prediction who propose that education reduces misconceptions in general. They also predict that students with higher cognitive ability and higher need for cognition are less susceptible to biases. In Experiments 1 and 2 we found that the equiprobability bias increased with statistics education, and it was negatively correlated with students’ cognitive abilities. The representativeness heuristic was mostly unaffected by education, and it was also unrelated to cognitive abilities. In Experiment 3 we demonstrated through an instruction manipulation (by asking participants to think logically vs. rely on their intuitions) that the reason for these differences was that these biases originated in different cognitive processes.

Multiple cutout optimization in composite plates using evolutionary structural optimization

The optimization of cutouts in composite plates was investigated by implementing a procedure known as Evolutionary Structural Optimization. Perforations were introduced into a finite element mesh of the plate from which one or more cutouts of a predetermined size were evolved. In the examples presented, plates were rejected from around each evolving cutout based on a predefined rejection criterion. The Limiting ply within each plate element around the cutout was determined based on the Tsai-Hill failure criterion. Finite element plates with values below the product of the average Tsai-Hill number and a rejection criterion were subsequently removed. This process was iterated until a steady state was reached and the rejection criterion was then incremented by an evolutionary rate and the above steps repeated until the desired cutout area was achieved. Various plates with differing lay-up and loading parameters were investigated to demonstrate the generality and robustness of this optimization procedure.

Complex pattern of genetic structuring in the Atlantic salmon (Salmo salar L.) of the River Foyle system in northwest Ireland: disentangling the evolutionary signal from population stochasticity

Little is known about the microevolutionary processes shaping within river population genetic structure of aquatic organisms characterized by high levels of homing and spawning site fidelity. Using a microsatellite panel, we observed complex and highly significant levels of intrariver population genetic substructure and Isolation-by-Distance, in the Atlantic salmon stock of a large river system. Two evolutionary models have been considered explaining mechanisms promoting genetic substructuring in Atlantic salmon, the member-vagrant and metapopulation models. We show that both models can be simultaneously used to explain patterns and levels of population structuring within the Foyle system. We show that anthropogenic factors have had a large influence on contemporary population structure observed. In an analytical development, we found that the frequently used estimator of genetic differentiation, F-ST, routinely underestimated genetic differentiation by a factor three to four compared to the equivalent statistic Jost's D-est (Jost 2008). These statistics also showed a near-perfect correlation. Despite ongoing discussions regarding the usefulness of "adjusted" F-ST statistics, we argue that these could be useful to identify and quantify qualitative differences between populations, which are important from management and conservation perspectives as an indicator of existence of biologically significant variation among tributary populations or a warning of critical environmental damage.

Stress, Positive Psychology and the National Student Survey

The aim was to explore the predictive ability of sources of stress and a range of dispositional and coping behaviours on student satisfaction and motivation. Most research exploring sources of stress and coping in students construes stress as psychological distress, with little attempt to consider positive experiences of stress. A questionnaire was administered to 120 first-year UK psychology students. Questions were asked which measured sources of stress when rated as likely to contribute to distress (a hassle) and likely to help one achieve (an uplift). The sources of stress were amended from the UK National Student Survey (NSS, 2011). Support, control, self-efficacy, personality and coping style were also measured, along with their potential affect on
course satisfaction, motivation and feeling part of a learning community. The sources of stress likely to lead to distress were more often significant than sources of stress likely to lead to positive, eustress states. Ironically,
factors one would consider would help students, such as the university support facilities, only did so when rated as a hassle, not as an uplift. Published university league tables draw heavily on student course satisfaction but this negatively correlated with intellectual motivation and feeling part of a learning
community. This suggests course satisfaction alone reveals an incomplete picture of the student experience. Course educators need to consider how course experiences contribute not just to potential distress but to
potential eustress. Teaching quality, effective support and work-life balance are key to student satisfaction and motivation. How educators interact with their students and the opportunities they create in and outside the class to promote peer support are likely to enhance satisfaction and motivation.

Children’s Views Matter Too! A Pilot Project Assessing Children’s and Adolescents’ Experiences of Clinical Psychology Services

This pilot study explored the experiences and understanding of clinical psychology practices and services of children and adolescents attending clinical psychology outpatient appointments. Fifteen young participants took part in the study. A content analysis indicated that young children and adolescents have an appropriate understanding of the role of the clinical psychologist, with older children commenting on the uniqueness and value of the therapeutic relationship. Attendance was rated as positive and helpful with regards to difficulties across all ages; however, many children were not consulted with at the point of referral and many did not know why they were attending. Implications for assessing children's and adolescents’ experiences of clinical psychology services are discussed.