Assessing when chromosomal rearrangements affect the dynamics of speciation: implications from computer simulations.

Many hypotheses have been put forth to explain the origin and spread of inversions, and their significance for speciation. Several recent genic models have proposed that inversions promote speciation with gene flow due to the adaptive significance of the genes contained within them and because of the effects inversions have on suppressing recombination. However, the consequences of inversions for the dynamics of genome wide divergence across the speciation continuum remain unclear, an issue we examine here. We review a framework for the genomics of speciation involving the congealing of the genome into alternate adaptive states representing species ("genome wide congealing"). We then place inversions in this context as examples of how genetic hitchhiking can potentially hasten genome wide congealing. Specifically, we use simulation models to (i) examine the conditions under which inversions may speed genome congealing and (ii) quantify predicted magnitudes of these effects. Effects of inversions on promoting speciation were most common and pronounced when inversions were initially fixed between populations before secondary contact and adaptation involved many genes with small fitness effects. Further work is required on the role of underdominance and epistasis between a few loci of major effect within inversions. The results highlight five important aspects of the roles of inversions in speciation: (i) the geographic context of the origins and spread of inversions, (ii) the conditions under which inversions can facilitate divergence, (iii) the magnitude of that facilitation, (iv) the extent to which the buildup of divergence is likely to be biased within vs. outside of inversions, and (v) the dynamics of the appearance and disappearance of exceptional divergence within inversions. We conclude by discussing the empirical challenges in showing that inversions play a central role in facilitating speciation with gene flow

Reading fiction and reading minds : the role of simulation in the default network

Research in psychology has suggested that reading fiction can improve individuals’ social-cognitive abilities. Findings from neuroscience show that reading and social cognition both recruit the default network, a network which is known to support our capacity to simulate hypothetical scenes, spaces and mental states. The current research tests the hypothesis that fiction reading enhances social cognition because it serves to exercise the default subnetwork involved in theory of mind. While undergoing functional neuroimaging, participants read literary passages that differed along two dimensions: (i) vivid vs abstract and (ii) social vs non-social. Analyses revealed distinct subnetworks of the default network respond to the two dimensions of interest: the medial temporal lobe subnetwork responded preferentially to vivid passages, with or without social content; the dorsomedial prefrontal cortex (dmPFC) subnetwork responded preferentially to passages with social and abstract content. Analyses also demonstrated that participants who read fiction most often also showed the strongest social cognition performance. Finally, mediation analysis showed that activity in the dmPFC subnetwork in response to the social content mediated this relation, suggesting that the simulation of social content in fiction plays a role in fiction’s ability to enhance readers’ social cognition

Optimizing Radiology Peer Review: A Mathematical Model for Selecting Future Cases Based on Prior Errors

Introduction: Peer review is an essential process for physicians because it facilitates improved quality of patient care and continuing physician learning and improvement. However, peer review often is not well received by radiologists, who note that it is time intensive, subjective, and lacks demonstrable impact on patient care. Current advances in peer review include the RADPEER system with its standardization of discrepancies and incorporation of the peer review process into the PACS itself. Our purpose was to build on RADPEER and similar systems by using a mathematical model to optimally select the types of cases to be reviewed, for each radiologist undergoing review, based on the past frequency of interpretive error, likelihood of morbidity from an error, financial cost of an error, and time required for the reviewing radiologist to interpret the study. Methods: We compiled 612,890 preliminary radiology reports authored by residents and attendings of a large tertiary-care medical center from 1999 to 2004. Discrepancies between preliminary and final interpretations were classified by severity and validated by re-review of major discrepancies. A mathematical model was then used to calculate, for each author of a preliminary report, the combined morbidity and financial costs of expected errors across three modalities (MRI, CT, and CR) and four departmental divisions (Neuroradiology and Abdominal, Musculoskelatal, and Thoracic Imaging). Results: A customized report was generated for each on-call radiologist which determined the category (modality and body part) with the highest total cost function. A universal total cost based on probability data from all radiologists was also compiled. Conclusion: The use of mathematical models to guide case selection could optimize the efficiency and effectiveness of physician time spent on peer review and produce more concrete and meaningful feedback to radiologists undergoing peer review

Ecological Adaptation and Speciation: The Evolutionary Significance of Habitat Avoidance as a Postzygotic Reproductive Barrier to Gene Flow

Habitat choice is an important component of most models of ecologically based speciation, especially when population divergence occurs in the face of gene flow. We examine how organisms choose habitats and ask whether avoidance behavior plays an important role in habitat choice, focusing on host-specific phytophagous insects as model systems. We contend that when a component of habitat choice involves avoidance, there can be repercussions that can have consequences for enhancing the potential for specialization and postzygotic reproductive isolation and, hence, for ecological speciation. We discuss theoretical and empirical reasons for why avoidance behavior has not been fully recognized as a key element in habitat choice and ecological speciation. We present current evidence for habitat avoidance, emphasizing phytophagous insects, and new results for parasitoid wasps consistent with the avoidance hypothesis. We conclude by discussing avenues for further study, including other potential roles for avoidance behavior in speciation related to sexual selection and reinforcement

Comparing Peripheral Olfactory Coding with Host Preference in the Rhagoletis Species Complex

Recent studies have shown that flies from sympatric populations of Rhagoletis pomonella infesting hawthorn, apple, and flowering dogwood fruit can distinguish among unique volatile blends identified from each host. Analysis of peripheral chemoreception in Rhagoletis flies suggests that changes in receptor specificity and/or receptor neuron sensitivity could impact olfactory preference among the host populations and their hybrids. In an attempt to validate these claims, we have combined flight tunnel analyses and single sensillum electrophysiology in F2 and backcross hybrids displaying a variety of behavioral phenotypes. Results show that differences in peripheral chemoreception among second-generation adults do not provide a direct correlation between peripheral coding and olfactory behavior. We conclude that either the plasticity of the central nervous system in Rhagoletis can compensate for significant alterations in peripheral coding or that peripheral changes present subtle effects on behavior not easily detectable with current techniques. The results of this study imply that the basis for olfactory behavior in Rhagoletis has a complicated genetic and neuronal basis, even for populations with a recent divergence in preferenc

Assessing for domestic violence in sexual health environments:a qualitative study

Objectives Domestic violence and abuse (DVA) is a major clinical challenge and public health issue. Sexual health services are an important potential site of DVA intervention. The Assessing for Domestic Violence in Sexual Health Environments (ADViSE) intervention aimed to improve identification and management of DVA in sexual healthcare settings and is a modified version of the Identification and Referral to Improve Safety (IRIS) general practice programme. Our qualitative evaluation aimed to explore the experiences of staff participating in an IRIS ADViSE pilot. Methods Interviews were conducted with 17 sexual health clinic staff and DVA advocate workers. Interviews were audio recorded, transcribed, anonymised and analysed thematically. Results Staff prioritised enquiring about DVA and tailored their style of enquiry to the perceived characteristics of patients, current workload and individual clinical judgements. Responding to disclosures of abuse was divided between perceived low-risk cases (with quick onwards referral) and high-risk cases (requiring deployment of institution safeguarding procedures), which were viewed as time consuming and could create tensions with patients. Ongoing training and feedback, commissioner recognition, adequate service-level agreements and reimbursements are required to ensure sustainability and wider implementation of IRIS ADViSE. Conclusions Challenges of delivering and sustaining IRIS ADViSE included the varied styles of enquiry, as well as tensions and additional time pressure arising from disclosure of abuse. These can be overcome by modifying initial training, providing regular updates and stronger recognition (and resources) at policy and commissioning levels

Domestic violence and self-poisoning in Sri Lanka

Background. There is increasing evidence that domestic violence (DV) is an important risk factor for suicidal behaviour. The level of risk and its contribution to the overall burden of suicidal behaviour among men and women has not been quantified in South Asia. We carried out a large case-control study to examine the association between DV and self-poisoning in Sri Lanka. Methods. Cases (N = 291) were patients aged ⩾18 years, admitted to a tertiary hospital in Kandy Sri Lanka for self-poisoning. Sex and age frequency matched controls were recruited from the hospital’s outpatient department (N = 490) and local population (N = 450). Exposure to DV was collected through the Humiliation, Afraid, Rape, Kick questionnaire. Multivariable logistic regression models were conducted to estimate the association between DV and self-poisoning, and population attributable fractions were calculated. Results. Exposure to at least one type of DV within the previous 12 months was strongly associated with self-poisoning for women [adjusted OR (AOR) 4.08, 95% CI 1.60–4.78] and men (AOR 2.52, 95% CI 1.51–4.21), compared to those reporting no abuse. Among women, the association was strongest for physical violence (AOR 14.07, 95% CI 5.87–33.72), whereas among men, emotional abuse showed the highest risk (AOR 2.75, 95% CI 1.57–4.82). PAF % for exposure to at least one type of DV was 38% (95% CI 32–43) in women and 22% (95% CI 14–29) in men. Conclusions. Multi-sectoral interventions to address DV including enhanced identification in health care settings, community-based strategies, and integration of DV support and psychological services may substantially reduce suicidal behaviour in Sri Lanka

Quantitative and Rapid DNA Detection by Laser Transmission Spectroscopy

Laser transmission spectroscopy (LTS) is a quantitative and rapid in vitro technique for measuring the size, shape, and number of nanoparticles in suspension. Here we report on the application of LTS as a novel detection method for species-specific DNA where the presence of one invasive species was differentiated from a closely related invasive sister species. The method employs carboxylated polystyrene nanoparticles functionalized with short DNA fragments that are complimentary to a specific target DNA sequence. In solution, the DNA strands containing targets bind to the tags resulting in a sizable increase in the nanoparticle diameter, which is rapidly and quantitatively measured using LTS. DNA strands that do not contain the target sequence do not bind and produce no size change of the carboxylated beads. The results show that LTS has the potential to become a quantitative and rapid DNA detection method suitable for many real-world applications