HIV, Social Networks, and Loneliness among Older Adults in Uganda.

Loneliness among older adults has been identified as a major public health problem. Yet little is known about loneliness, or the potential role of social networks in explaining loneliness, among older people with HIV (PWH) in sub-Saharan Africa, where 70% of PWH reside. To explore this issue, we analyzed data from 599 participants enrolled in the Quality of Life and Ageing with HIV in Rural Uganda study, including older adults with HIV in ambulatory care and a comparator group of people without HIV of similar age and gender.

Phase transitions in evolutionary dynamics.

Sharp changes in state, such as transitions from survival to extinction, are hallmarks of evolutionary dynamics in biological systems. These transitions can be explored using the techniques of statistical physics and the physics of nonlinear and complex systems. For example, a survival-to-extinction transition can be characterized as a non-equilibrium phase transition to an absorbing state.

Phase transitions in biology: from bird flocks to population dynamics.

Phase transitions are an important and extensively studied concept in physics. The insights derived from understanding phase transitions in physics have recently and successfully been applied to a number of different phenomena in biological systems. Here, we provide a brief review of phase transitions and their role in explaining biological processes ranging from collective behaviour in animal flocks to neuronal firing.

Neural Synchronization, Chimera States and Sleep Asymmetry.

We model the dynamics of sleep states in two connected model brain hemispheres, using groups of coupled individual Hindmarsh-Rose neural oscillators. In a single isloated hemisphere, sleep-promoting neurons and wake-promoting neurons exhibit alternating levels of within-group mean field activity, as well as alternating levels of stochastic phase synchronization, as the system moves between simulated day and night. In a two-hemisphere model, we find differences in the behavior of the sleep-promototing or wake-promoting regions between hemispheres, indicative of chimera-like behavior.

Partial memory reinstatement while (lucid) dreaming to change the dream environment.

Lucid dreams often coincide with having control over dream events in real-time, although the limitations of dream control are not completely understood. The current study probed the ability of lucid dreamers to reinstate waking scene memories while dreaming. After brief exposure to an experimental scene, participants were asked to reinstate the scene while lucid dreaming (i.

Regional brain volumetric changes despite 2 years of treatment initiated during acute HIV infection.

Objective: To assess changes in regional brain volumes after 24 months among individuals who initiated combination antiretroviral therapy (cART) within weeks of HIV exposure.

Design: Prospective cohort study of Thai participants in the earliest stages of HIV-1infection.

Methods: Thirty-four acutely HIV-infected individuals (AHI; Fiebig I-V) underwent brain magnetic resonance (MR) imaging and MR spectroscopy at 1.

Furthering the Understanding of Wechsler Adult Intelligence Scale-Fourth Edition Factor Structure in a Clinical Sample.

The Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV) is a commonly administered battery for assessing intellectual and cognitive abilities. Despite its popularity, construct validation studies primarily utilize the WAIS-IV normative sample rather than ecologically-valid clinical samples. The current study expands the literature on the validity of WAIS-IV by testing a bifactor model in such a sample.

High correlations between MRI brain volume measurements based on NeuroQuant and FreeSurfer.

NeuroQuant (NQ) and FreeSurfer (FS) are commonly used computer-automated programs for measuring MRI brain volume. Previously they were reported to have high intermethod reliabilities but often large intermethod effect size differences. We hypothesized that linear transformations could be used to reduce the large effect sizes.

Examination of the Construct Validity of the Repeatable Battery for the Assessment of Neuropsychological Status Language Index in a Mixed Neurological Sample.

Objective: We sought to examine the construct validity of the Language Index of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS).

Methods: Archival neuropsychological data were collected for 2,057 individuals of diverse neurological etiologies.

Results: Correlations were seen between the RBANS Language Index and its indices (Semantic Fluency r = .

Multiple phase transitions in an agent-based evolutionary model with neutral fitness.

Null models are crucial for understanding evolutionary processes such as speciation and adaptive radiation. We analyse an agent-based null model, considering a case without selection-neutral evolution-in which organisms are defined only by phenotype. Universal dynamics has previously been demonstrated in a related model on a neutral fitness landscape, showing that this system belongs to the directed percolation (DP) universality class.

The genome sequence and insights into the immunogenetics of the bananaquit (Passeriformes: Coereba flaveola).

Avian genomics, especially of non-model species, is in its infancy relative to mammalian genomics. Here, we describe the sequencing, assembly, and annotation of a new avian genome, that of the bananaquit Coereba flaveola (Passeriformes: Thraupidae). We produced ∼30-fold coverage of the genome with an assembly size of ca.

Chimera states in a Hodgkin-Huxley model of thermally sensitive neurons.

Chimera states occur when identically coupled groups of nonlinear oscillators exhibit radically different dynamics, with one group exhibiting synchronized oscillations and the other desynchronized behavior. This dynamical phenomenon has recently been studied in computational models and demonstrated experimentally in mechanical, optical, and chemical systems. The theoretical basis of these states is currently under active investigation.

Clinician Effectiveness in Assessing Fitness to Drive of Medically At-Risk Older Adults.

Objectives: To model the relative contributions of driver data and clinical judgments to clinical ratings of driver capability for a state licensing authority and to compare ratings with on-road test results.

Design: Retrospective, logistic regression.

Setting: Missouri Driver License Bureau.

Treatment of persistent post-concussive symptoms after mild traumatic brain injury: a systematic review of cognitive rehabilitation and behavioral health interventions in military service members and veterans.

Increased prevalence of traumatic brain injury (TBI) has been associated with service members and veterans who completed combat deployments in support of Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF). Management of persistent post-concussive symptoms (PCS) has been a challenge to healthcare providers throughout the Military and Veterans Healthcare Systems, as well as civilian healthcare providers, due in part to the chronic nature of symptoms, co-occurrence of behavioral health disorders such as depression, Posttraumatic Stress Disorder (PTSD), and substance use disorders, and fear of a potential stigma associated with psychiatric diagnoses and behavioral health treatment(s). This systematic review examined non-pharmacologic behavioral health interventions and cognitive rehabilitation interventions for PCS in military service members and veterans with a history of mild TBI (mTBI).

Synchronization analysis of voltage-sensitive dye imaging during focal seizures in the rat neocortex.

Seizures are often assumed to result from an excess of synchronized neural activity. However, various recent studies have suggested that this is not necessarily the case. We investigate synchronization during focal neocortical seizures induced by injection of 4-aminopyridine (4AP) in the rat neocortex in vivo.

Introduction to Focus Issue: nonlinear and stochastic physics in biology.

Frank Moss was a leading figure in the study of nonlinear and stochastic processes in biological systems. His work, particularly in the area of stochastic resonance, has been highly influential to the interdisciplinary scientific community. This Focus Issue pays tribute to Moss with articles that describe the most recent advances in the field he helped to create.

Using previous models to bias structural learning in the hierarchical BOA.

Estimation of distribution algorithms (EDAs) are stochastic optimization techniques that explore the space of potential solutions by building and sampling explicit probabilistic models of promising candidate solutions. While the primary goal of applying EDAs is to discover the global optimum or at least its accurate approximation, besides this, any EDA provides us with a sequence of probabilistic models, which in most cases hold a great deal of information about the problem. Although using problem-specific knowledge has been shown to significantly improve performance of EDAs and other evolutionary algorithms, this readily available source of problem-specific information has been practically ignored by the EDA community.

Effect of cognitive load on eye-target synchronization during smooth pursuit eye movement.

In mild traumatic brain injury (mTBI), the fiber tracts that connect the frontal cortex with the cerebellum may suffer shear damage, leading to attention deficits and performance variability. This damage also disrupts the enhancement of eye-target synchronization that can be affected by cognitive load when subjects are tested using a concurrent eye-tracking test and word-recall test. We investigated the effect of cognitive load on eye-target synchronization in normal and mTBI patients using the nonlinear dynamical technique of stochastic phase synchronization.

Mutation size optimizes speciation in an evolutionary model.

The role of mutation rate in optimizing key features of evolutionary dynamics has recently been investigated in various computational models. Here, we address the related question of how maximum mutation size affects the formation of species in a simple computational evolutionary model. We find that the number of species is maximized for intermediate values of a mutation size parameter mu; the result is observed for evolving organisms on a randomly changing landscape as well as in a version of the model where negative feedback exists between the local population size and the fitness provided by the landscape.

CEO- CNE relationships: building an evidence-base of chief nursing executive replacement costs.

Objective: Explore professional relationships between Chief Nurse Executives (CNEs) and Chief Executive Officers (CEOs); CNE ethnic diversity; and CNE replacement costs.

Background: Theoretical frameworks - Marilyn Ray's Theory of Bureaucratic Caring, and Turkel's Theory of Relational Complexity espousing economic as well as caring variables.

Methods: Exploratory mixed-method descriptive design using CNE mailed survey.

Stochastic resonance and the evolution of Daphnia foraging strategy.

Search strategies are currently of great interest, with reports on foraging ranging from albatrosses and spider monkeys to microzooplankton. Here, we investigate the role of noise in optimizing search strategies. We focus on the zooplankton Daphnia, which move in successive sequences consisting of a hop, a pause and a turn through an angle.