2,956 research outputs found

    The feasibility of a cognitive behavioural therapy group for men with mild/moderate cognitive impairment

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    Memory aid groups have often been used as a method for teaching mnemonic strategies to older adults in early stages of dementia. This study describes the use of CBT to address unhelpful memory-related beliefs in three older men with mild/moderate dementia and associated low mood or anxiety. The members were able to participate and engage in the sessions, and changes in behaviour, cognition and affect were monitored over the course of a 7 week group intervention. Recommendations are made for further research

    The Adaptation and Feasibility of Narrative Enhancement and Cognitive Therapy (NECT) for Late-Onset Psychosis

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    The aim of this study is to adapt and feasibility test the narrative component of Narrative Enhancement and Cognitive Therapy (NECT) for late-onset psychosis. This study followed the development and feasibility phases of the Medical Research Council framework. The original NECT intervention was adapted based on consultations with service users, experts, and clinicians. The evaluation of the feasibility test of the adapted intervention was guided by Orsmond and Cohn (Occup Particip Health 35(3):169-177, 2015)'s model for feasibility studies. The final adaptations consist of language, readability, and delivery. The adapted intervention was tested for feasibility and acceptability with one group of five patients recruited from a National Health Service (NHS) Trust in UK Results were mixed in participant outcomes and a likelihood of acceptability of the intervention. This indicates the need for a larger scale feasibility test to explore the identified benefits and challenges of implementing NECT in NHS or community settings for late-onset psychosis

    Emergence of rich-club topology and coordinated dynamics in development of hippocampal functional networks in vitro.

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    Recent studies demonstrated that the anatomical network of the human brain shows a "rich-club" organization. This complex topological feature implies that highly connected regions, hubs of the large-scale brain network, are more densely interconnected with each other than expected by chance. Rich-club nodes were traversed by a majority of short paths between peripheral regions, underlining their potential importance for efficient global exchange of information between functionally specialized areas of the brain. Network hubs have also been described at the microscale of brain connectivity (so-called "hub neurons"). Their role in shaping synchronous dynamics and forming microcircuit wiring during development, however, is not yet fully understood. The present study aimed to investigate the role of hubs during network development, using multi-electrode arrays and functional connectivity analysis during spontaneous multi-unit activity (MUA) of dissociated primary mouse hippocampal neurons. Over the first 4 weeks in vitro, functional connectivity significantly increased in strength, density, and size, with mature networks demonstrating a robust modular and small-world topology. As expected by a "rich-get-richer" growth rule of network evolution, MUA graphs were found to form rich-clubs at an early stage in development (14 DIV). Later on, rich-club nodes were a consistent topological feature of MUA graphs, demonstrating high nodal strength, efficiency, and centrality. Rich-club nodes were also found to be crucial for MUA dynamics. They often served as broker of spontaneous activity flow, confirming that hub nodes and rich-clubs may play an important role in coordinating functional dynamics at the microcircuit level.M.S.S. is supported by a PhD studentship funded by a Core Award from the Medical Research Council and the Wellcome Trust to the Behavioural and Clinical Neuroscience Institute (MRC Ref G1000183; WT Ref 093875/Z/10/Z) and by the Studienstiftung des deutschen Volkes. Additional support for this study from the Biotechnology and Biological Sciences Research Council (BBSRC Ref BB/H008608/1) is gratefully acknowledged.This is the final published version. It first appeared at http://www.jneurosci.org/content/35/14/5459.full

    Kinetic theory of age-structured stochastic birth-death processes

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    Classical age-structured mass-action models such as the McKendrick-von Foerster equation have been extensively studied but are unable to describe stochastic fluctuations or population-size-dependent birth and death rates. Stochastic theories that treat semi-Markov age-dependent processes using, e.g., the Bellman-Harris equation do not resolve a population's age structure and are unable to quantify population-size dependencies. Conversely, current theories that include size-dependent population dynamics (e.g., mathematical models that include carrying capacity such as the logistic equation) cannot be easily extended to take into account age-dependent birth and death rates. In this paper, we present a systematic derivation of a new, fully stochastic kinetic theory for interacting age-structured populations. By defining multiparticle probability density functions, we derive a hierarchy of kinetic equations for the stochastic evolution of an aging population undergoing birth and death. We show that the fully stochastic age-dependent birth-death process precludes factorization of the corresponding probability densities, which then must be solved by using a Bogoliubov-–Born–-Green–-Kirkwood-–Yvon-like hierarchy. Explicit solutions are derived in three limits: no birth, no death, and steady state. These are then compared with their corresponding mean-field results. Our results generalize both deterministic models and existing master equation approaches by providing an intuitive and efficient way to simultaneously model age- and population-dependent stochastic dynamics applicable to the study of demography, stem cell dynamics, and disease evolution

    Maximum principle and mutation thresholds for four-letter sequence evolution

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    A four-state mutation-selection model for the evolution of populations of DNA-sequences is investigated with particular interest in the phenomenon of error thresholds. The mutation model considered is the Kimura 3ST mutation scheme, fitness functions, which determine the selection process, come from the permutation-invariant class. Error thresholds can be found for various fitness functions, the phase diagrams are more interesting than for equivalent two-state models. Results for (small) finite sequence lengths are compared with those for infinite sequence length, obtained via a maximum principle that is equivalent to the principle of minimal free energy in physics.Comment: 25 pages, 16 figure

    Action or inaction: bystander intervention in workplace sexual harassment

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    A promising approach to the persistent problem of workplace sexual harassment (SH) is encouraging interventions by bystanders. Adopting a typology developed by Bowes-Sperry and O'Leary-Kelly that considers the level of immediacy and involvement of bystander interventions, this study explored 74 detailed descriptions of SH events that occurred in Australian workplaces. The findings reveal that despite the hidden nature of SH, there is significant involvement of actors who are not direct targets but their actions are frequently delayed, temporary or ineffective. The study makes two contributions to the study and practice of HRM. First, it provides important evidence of the different ways that bystanders respond to SH in real workplaces and the relative likelihood of these actions. Second, the study points to relevant contextual features evident in the scenarios described which determine if and how bystanders intervene. We discuss the utility of the bystander framework for future research and practice, including the development of bystander interventions as a potentially innovative response to the persistent and damaging problem of workplace SH

    Developing a framework of effective prevention and response strategies in workplace sexual harassment

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    Sexual harassment remains a widespread workplace phenomenon, despite laws that proscribe it. Drawing initially on a typology from the violence prevention literature that conceptualizes prevention and response approaches according to when they occur, the paper synthesizes strategies identified in literature addressing workplace sexual harassment, as well as other workplace injustices or grievances. The paper utilizes this previous research to develop a framework of sexual harassment prevention strategies along two dimensions: functions and timing. The framework offers a research-informed set of organization-wide preventative and remedial approaches, a systemic approach to what is often seen as an individual problem, and a means to better focus interventions that are often disparate and unco-ordinated. The paper also highlights important areas for future research including a stronger focus on longer-term (tertiary) corrective actions

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

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    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

    Time evolution of the Partridge-Barton Model

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    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 tt 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−1t^{-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

    Does Good Mutation Help You Live Longer?

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    We study the dynamics of an age-structured population in which the life expectancy of an offspring may be mutated with respect to that of its parent. When advantageous mutation is favored, the average fitness of the population grows linearly with time tt, while in the opposite case the average fitness is constant. For no mutational bias, the average fitness grows as t^{2/3}. The average age of the population remains finite in all cases and paradoxically is a decreasing function of the overall population fitness.Comment: 4 pages, 2 figures, RevTeX revised version, to appear in Phys. Rev. Let
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