Neuropsychological evaluation of blast-related concussion: Illustrating the challenges and complexities through OEF/OIF case studies

Background/objective: Soldiers of Operations Enduring Freedom (OEF) and Iraqi Freedom (OIF) sustain blast-related mild traumatic brain injury (concussion) with alarming regularity. This study discusses factors in addition to concussion, such as co-morbid psychological difficulty (e.g. post-traumatic stress) and symptom validity concerns that may complicate neuropsychological evaluation in the late stage of concussive injury. Case report: The study presents the complexities that accompany neuropsychological evaluation of blast concussion through discussion of three case reports of OEF/OIF personnel. Discussion: The authors emphasize uniform assessment of blast concussion, the importance of determining concussion severity according to acute-injury characteristics and elaborate upon non-concussion-related factors that may impact course of cognitive limitation. The authors conclude with a discussion of the need for future research examining the impact of blast concussion (particularly recurrent concussion) and neuropsychological performance

Evaluation Context Impacts Neuropsychological Performance of OEF/OIF Veterans with Reported Combat-Related Concussion

Although soldiers of Operations Iraqi Freedom (OIF) and Enduring Freedom (OEF) encounter combat-related concussion at an unprecedented rate, relatively few studies have examined how evaluation context, insufficient effort, and concussion history impact neuropsychological performances in the years following injury. The current study explores these issues in a sample of 119 U.S. veterans (OEF/OIF forensic concussion, n = 24; non-OEF/OIF forensic concussion, n = 20; OEF/OIF research concussion, n = 38; OEF/OIF research without concussion, n = 37). The OEF/OIF forensic concussion group exhibited significantly higher rates of insufficient effort relative to the OEF/OIF research concussion group, but a comparable rate of insufficient effort relative to the non-OEF/OIF forensic concussion group. After controlling for effort, the research concussion and the research non-concussion groups demonstrated comparable neuropsychological performance. Results highlight the importance of effort assessment among OEF/OIF and other veterans with concussion history, particularly in forensic contexts

A scoping study on measuring and monitoring tools and technology for precision irrigation

This scoping study is designed to advance high standards of precision in management of water and develop efficient methods of irrigation prescription to reduce losses and improve water use efficiency. All aspects of irrigation process are considered in this study to include various components of farm water storage and distribution systems to facilitate accurate accounting of water. In this study, we will attempt to: * Identify key attributes and specifications for various tools (sensors and control systems) for precision irrigation management; * Develop strategies to fill current gaps in the functionality of various tools and technology available for irrigation and * Prioritise opportunities to refine and/or develop new tools and technology to increase on-farm precision and meet off-farm hydrology needs

Recombination dramatically speeds up evolution of finite populations

We study the role of recombination, as practiced by genetically-competent bacteria, in speeding up Darwinian evolution. This is done by adding a new process to a previously-studied Markov model of evolution on a smooth fitness landscape; this new process allows alleles to be exchanged with those in the surrounding medium. Our results, both numerical and analytic, indicate that for a wide range of intermediate population sizes, recombination dramatically speeds up the evolutionary advance

Patterns of intron sequence evolution in Drosophila are dependent upon length and GC content

BACKGROUND: Introns comprise a large fraction of eukaryotic genomes, yet little is known about their functional significance. Regulatory elements have been mapped to some introns, though these are believed to account for only a small fraction of genome wide intronic DNA. No consistent patterns have emerged from studies that have investigated general levels of evolutionary constraint in introns. RESULTS: We examine the relationship between intron length and levels of evolutionary constraint by analyzing inter-specific divergence at 225 intron fragments in Drosophila melanogaster and Drosophila simulans, sampled from a broad distribution of intron lengths. We document a strongly negative correlation between intron length and divergence. Interestingly, we also find that divergence in introns is negatively correlated with GC content. This relationship does not account for the correlation between intron length and divergence, however, and may simply reflect local variation in mutational rates or biases. CONCLUSION: Short introns make up only a small fraction of total intronic DNA in the genome. Our finding that long introns evolve more slowly than average implies that, while the majority of introns in the Drosophila genome may experience little or no selective constraint, most intronic DNA in the genome is likely to be evolving under considerable constraint. Our results suggest that functional elements may be ubiquitous within longer introns and that these introns may have a more general role in regulating gene expression than previously appreciated. Our finding that GC content and divergence are negatively correlated in introns has important implications for the interpretation of the correlation between divergence and levels of codon bias observed in Drosophila

Barriers and facilitators to providing CBT for people living with dementia: perceptions of psychological therapists

Many people living with dementia or mild cognitive impairment (MCI) experience anxiety and depression. Cognitive behavioral therapy (CBT) is a recommended treatment for adults, commonly provided through primary care psychological therapies services. This study explored the facilitators and barriers to providing CBT interventions for people living with dementia or MCI, as perceived by therapists working in such services. Structured interviews were conducted with fourteen clinicians recruited through primary care psychological therapies services about their experiences of working with people living with dementia or MCI and their ideas about factors that enhance or hinder offering and delivering CBT to this population. Interview recordings were transcribed and analyzed using Thematic Analysis. Credibility checks were incorporated throughout. Three themes were identified: 'attitudes towards dementia', 'competing demands', and 'pressure without support'. Perceived facilitators and barriers occurred across individual, service, and system levels. Facilitators were: positive engagement and outcomes for people living with dementia or MCI, positive attitudes of clinicians, and flexibility within some services. In contrast, perceived barriers were: stigma towards dementia and mental health in older adults, high pressure on staff to perform with a lack of support to do so, exclusion based on diagnosis, and inflexibility within some services. Clinicians were confident that people living with dementia or MCI could benefit from CBT, with some adaptations to delivery. There are implications for staff support and training, and for commissioning practices relating to the tension between minimal resources, equitable access, and person-centered care

Reduced efficacy of selection in regions of the Drosophila genome that lack crossing over

BACKGROUND: The recombinational environment is predicted to influence patterns of protein sequence evolution through the effects of Hill-Robertson interference among linked sites subject to selection. In freely recombining regions of the genome, selection should more effectively incorporate new beneficial mutations, and eliminate deleterious ones, than in regions with low rates of genetic recombination. RESULTS: We examined the effects of recombinational environment on patterns of evolution using a genome-wide comparison of Drosophila melanogaster and D. yakuba. In regions of the genome with no crossing over, we find elevated divergence at nonsynonymous sites and in long introns, a virtual absence of codon usage bias, and an increase in gene length. However, we find little evidence for differences in patterns of evolution between regions with high, intermediate, and low crossover frequencies. In addition, genes on the fourth chromosome exhibit more extreme deviations from regions with crossing over than do other, no crossover genes outside the fourth chromosome. CONCLUSION: All of the patterns observed are consistent with a severe reduction in the efficacy of selection in the absence of crossing over, resulting in the accumulation of deleterious mutations in these regions. Our results also suggest that even a very low frequency of crossing over may be enough to maintain the efficacy of selection

Time evolution of the Partridge-Barton Model

The time evolution of the Partridge-Barton model in the presence of the pleiotropic constraint and deleterious somatic mutations is exactly solved for arbitrary fecundity in the context of a matricial formalism. Analytical expressions for the time dependence of the mean survival probabilities are derived. Using the fact that the asymptotic behavior for large time $t$ is controlled by the largest matrix eigenvalue, we obtain the steady state values for the mean survival probabilities and the Malthusian growth exponent. The mean age of the population exhibits a $t^{-1}$ power law decayment. Some Monte Carlo simulations were also performed and they corroborated our theoretical results.Comment: 10 pages, Latex, 1 postscript figure, published in Phys. Rev. E 61, 5664 (2000

Stigma among UK family carers of people living with dementia

Background Models of caregiving seldom include the role of stigma when understanding the experiences of carers of people living with dementia. Aims To investigate the validity of the Family Stigma Instrument (FAMSI), and use it to explore the extent to which experiences of stigma are endorsed in family carers of people living with dementia. Method The FAMSI was tested with 70 carers of people living with dementia. They also completed a measure of self-esteem. Results The FAMSI demonstrated some good preliminary psychometric properties. Carers endorsed stigma by association more so than affiliate stigma constructs, suggesting that carers were aware that others viewed or treated them in a stigmatising fashion but did not endorse internalised consequences of this as much (e.g. behavioural or affective affiliate stigma). Conclusions The FAMSI offers new avenues for understanding the contribution of stigma to caregiver burden in dementia. It also captures the positive aspects of caregiving, which may mitigate internalised stigma in family carers, and has good potential for evaluating stigma-neutralising interventions in dementia care

Survival-extinction phase transition in a bit-string population with mutation

A bit-string model for the evolution of a population of haploid organisms, subject to competition, reproduction with mutation and selection is studied, using mean field theory and Monte Carlo simulations. We show that, depending on environmental flexibility and genetic variability, the model exhibits a phase transtion between extinction and survival. The mean-field theory describes the infinite-size limit, while simulations are used to study quasi-stationary properties.Comment: 11 pages, 5 figure