The role of hyperarousal in the manifestation of posttraumatic psychological distress following injury

The authors examined the temporal relation among posttraumatic stress disorder symptom clusters, using data derived from a longitudinal study of survivors of orofacial injury (N = 264). They conducted cross-lagged panel analyses, with self-reported symptom data collected at 1, 6, and 12 months postinjury. Results demonstrate that hyperarousal was a potent predictor of subsequent symptoms of reexperiencing and avoidance as well as hyperarousal. By contrast, neither reexperiencing nor avoidance was significantly related to other symptom clusters other than themselves over time. These findings underscore the distinctive nature of hyperarousal in the manifestation of posttraumatic psychological distress over time. Implications for theory, clinical intervention, and future research are discussed.     

The key role of nanoscale surface facets on the mechanical strength and failure of wurtzite and periodically twinned zinc-blende nanowires

Using molecular dynamics, we study the role of the surface facets of III–V nanowires on their failure during tensile deformation. We find that wurtzite (WZ) nanowires can withstand higher levels of stress and strain at failure compared to zinc-blende (ZB) nanowires. We observe that it is easier to nucleate a crack on a ZB nanowire due to the stress singularities that occur at the intersection of two opposing {111} facets. In WZ nanowires, we observe that cracks always nucleate at the intersection between two adjacent {112} surface facets. We explain these phenomena using fracture mechanics techniques based on energetics of crack formation.     

A Comparison of Latent Inhibition and Learned Irrelevance Pre-Exposure Effects in Rabbit and Human Eyeblink Conditioning

The learning of an association between a CS and a US can be retarded by unreinforced presentations of the CS alone (termed latent inhibition or LI) or by un-correlated presentations of the CS and US (termed learned irrelevance or LIRR). In rabbit eyeblink conditioning, there have been some recent failures to replicate LI. LIRR has been hypothesized as producing a stronger retardation effect than LI based on both empirical studies and computational models. In the work presented here, we examined the relative strength of LI and LIRR in eyeblink conditioning in rabbits and humans. In both species, a number of preexposure trials sufficient to produce LIRR failed to produce LI (Experiments 1 & 3). Doubling the number of CS pre-exposures did produce LI in rabbits (Experiment 2), but not in humans (Experiment 4). LI was demonstrated in humans only after manipulations including an increased inter-trial interval or ITI (Experiment 5). Overall, it appears that LIRR is a more easily producible pre-exposure retardation effect than LI for eyeblink conditioning in both rabbits and humans. Several theoretical mechanisms for LI including the conditioned attention theory, stimulus compression, novelty, and the switching theory are discussed as possible explanations for the differences between LIRR and LI. Overall, future work involving testing the neural substrates of pre-exposure effects may benefit from the use of LIRR rather than LI.     

Analyzing Big-Five Personality Traits of Indian Celebrities Using Online Social Media

Personality traits analysis has been an active area of research in information systems and its cognate disciplines. However, there are multiple challenges faced by questionnaire-based measurement of personality traits including low response rate and limited access to the individuals. This research paper presents a social media-based approach to determine the Big-Five personality traits of different groups of celebrities. First, authors collected the Twitter posts of celebrities in different professions and used IBM’s Watson Personality Insights tool to determine the personalities of these celebrities. Next, with the help of statistical analysis and visualization techniques, authors determined the personality pattern within and across the group of celebrities. The results demonstrate that there is significant difference across groups of celebrities on three of the Big-Five personality traits—Openness, Agreeableness, and Extraversion. However, there is no significant difference among the celebrity groups on the Conscientiousness and Neuroticism trait.     

Suicidality, clinical depression, and anxiety disorders are highly prevalent in men who have sex with men in Mumbai, India: findings from a community-recruited sample

In India men who have sex with men (MSM) are a stigmatized and hidden population, vulnerable to a variety of psychosocial and societal stressors. This population is also much more likely to be HIV-infected compared to the general population. However, little research exists about how psychosocial and societal stressors result in mental health problems. A confidential, quantitative mental-health interview was conducted among 150 MSM in Mumbai, India at The Humsafar Trust, the largest non-governmental organization serving MSM in India. The interview collected information on sociodemographics and assessed self-esteem, social support and DSM-IV psychiatric disorders using the Mini International Neuropsychiatric Interview (MINI). Participants' mean age was 25.1 years (SD?=?5.1); 21% were married to women. Forty-five percent reported current suicidal ideation, with 66% low risk, 19% moderate risk, and 15% high risk for suicide per MINI guidelines. Twenty-nine percent screened in for current major depression and 24% for any anxiety disorder. None of the respondents reported current treatment for any psychiatric disorder. In multivariable models controlling for age, education, income, and sexual identity, participants reporting higher levels of self-esteem and greater levels of satisfaction with the social support they receive from family and friends were at lower risk of suicidality (self-esteem AOR?=?0.85, 95% CI: 0.78-0.93; social support AOR?=?0.76, 95% CI: 0.62-0.93) and major depression (self-esteem AOR?=?0.79, 95% CI: 0.71-0.89; social support AOR?=?0.68, 95% CI: 0.54-0.85). Those who reported greater social support satisfaction were also at lower risk of a clinical diagnosis of an anxiety disorder (AOR?=?0.80; 95% CI: 0.65-0.99). MSM in Mumbai have high rates of suicidal ideation, depression, and anxiety. Programs to improve self-esteem and perceived social support may improve these mental health outcomes. Because they are also a high-risk group for HIV, MSM HIV prevention and treatment services may benefit from incorporating mental health services and referrals into their programs.     

The Chemical and Biological Warfare Environment: Psychological Responses and Social Supports in a High-Stress Environment

In order to better understand psychological responses to high-stress environments and the contributions of social supports to mediating the effects of this stress, we conducted a preliminary investigation of a health care delivery team in a simulated chemical and biological warfare (CBW) environment. Our data suggest that state anxiety prior to the exercise, perceived social support from family and friends, and active training stand out as predictors of psychological outcome, even after trait and pre-exercise psychological variables are considered. Interventions directed at state anxiety and active training may offer mechanisms to decrease the psychological distress of the high-stress environment. Future research should examine variables which are amenable to intervention to determine if they are causally related to health outcome in high-stress environments.     

Landscape of Machine Implemented Ethics

Science and Engineering Ethics - This paper surveys the state-of-the-art in machine ethics, that is, considerations of how to implement ethical behaviour in robots, unmanned autonomous vehicles, or...     

Age differences in prefrontal cortical activity in working memory

Working memory (WM) declines with advancing age. Brain imaging studies indicate that ventral prefrontal cortex (PFC) is active when information is retained in WM and that dorsal PFC is further activated for retention of large amounts of information. The authors examined the effect of aging on activation in specific PFC regions during WM performance. Six younger and 6 older adults performed a task in which, on each trial, they (a) encoded a 1- or 6-letter memory set, (b) maintained these letters over 5-s. and (c) determined whether or not a probe letter was part of the memory set. Comparisons of activation between the 1- and 6-letter conditions indicated age-equivalent ventral PFC activation. Younger adults showed greater dorsal PFC activation than older adults. Older adults showed greater rostral PFC activation than younger adults. Aging may affect dorsal PFC brain regions that are important for WM executive components.     

Neural substrates of word generation during stroke recovery: the influence of cortical hypoperfusion

Several studies have demonstrated reorganization of cognitive and motor function caused by stroke. This study examined the influence of hypoperfused brain regions, in addition to the area of the infarct itself, on reorganization of the cognitive processes underlying word generation in stroke patients. In addition, we also sought to determine the influence of hypoperfusion on the blood oxygen level dependent/(BOLD) effect. Subjects with left and right subacute or chronic subcortical strokes, along with normal controls, were imaged while performing a verbal fluency task (word generation). The study population included six normal subject and six stroke patients with subcortical infarcts and cortical hypoperfusion in the middle cerebral artery territory who had recovered or improved markedly in word fluency. While normal subjects displayed a left-lateralized fronto-temporo-parietal and bilateral cingulo-striatal-thalamic-cerebellar network, the activation pattern of stroke patients was determined both by the hypoperfused regions and infarcted areas of the brain. Specifically, patients showed diminished BOLD effect in the cortical regions that were hypoperfused, even though their infarcts were subcortical, and showed increased BOLD effect in the homologous regions of the normal hemisphere. This finding raises the possibility that cortical hypoperfusion in the absence of infarct can cause shift of language functions to the opposite, intact hemisphere. However, reduced BOLD effect in the task relative to rest was found in hypoperfused regions in two patients, raising the possibility that regional function persisted, even though vascular reactivity was impaired. Results illustrate the complexities of functional imaging studies of recovery in patients with vascular lesions.     

Equivalence of human odometry by walk and run is indifferent to self-selected speed

Humans and other animals can measure distances nonvisually by legged locomotion. Experiments typically employ an outbound measure (M) and an inbound report (R) phase. Previous research has found distance reproduction to be maximally accurate, when gait symmetry and speed of M and R are of like kind: Successful human odometry manifests at the level of the M-R system. In the present work, M was an experimenter-set distance produced by a blindfolded participant using a primary gait (walk, run). R was always by walk. Fast and slow versions of walk and run were adopted by participants, such that when M was fast R was slow, and vice versa. Distance was underestimated when M was slower than R and overestimated when M was faster than R. However, the pattern of participant-adopted velocities indicated that it was the instructions, not the speed as such, that yielded the pattern of results. The results are interpretable through a dynamical perspective and indicate speed is an imperfection parameter acting on the attractors of the M-R system.