Optimal measurement of visual motion across spatial and temporal scales

Sensory systems use limited resources to mediate the perception of a great variety of objects and events. Here a normative framework is presented for exploring how the problem of efficient allocation of resources can be solved in visual perception. Starting with a basic property of every measurement, captured by Gabor's uncertainty relation about the location and frequency content of signals, prescriptions are developed for optimal allocation of sensors for reliable perception of visual motion. This study reveals that a large-scale characteristic of human vision (the spatiotemporal contrast sensitivity function) is similar to the optimal prescription, and it suggests that some previously puzzling phenomena of visual sensitivity, adaptation, and perceptual organization have simple principled explanations.Comment: 28 pages, 10 figures, 2 appendices; in press in Favorskaya MN and Jain LC (Eds), Computer Vision in Advanced Control Systems using Conventional and Intelligent Paradigms, Intelligent Systems Reference Library, Springer-Verlag, Berli

Internal construct validity of the Warwick-Edinburgh Mental Well-being Scale (WEMWBS): a Rasch analysis using data from the Scottish Health Education Population Survey

Background: The Warwick-Edinburgh Mental Well-Being Scale (WEMWBS) was developed to meet demand for instruments to measure mental well-being. It comprises 14 positively phrased Likert-style items and fulfils classic criteria for scale development. We report here the internal construct validity of WEMWBS from the perspective of the Rasch measurement model. Methods: The model was applied to data collected from 779 respondents in Wave 12 (Autumn 2006) of the Scottish Health Education Population Survey. Respondents were aged 16–74 (average 41.9) yrs. Results: Initial fit to model expectations was poor. The items 'I've been feeling good about myself', 'I've been interested in new things' and 'I've been feeling cheerful' all showed significant misfit to model expectations, and were deleted. This led to a marginal improvement in fit to the model. After further analysis, more items were deleted and a strict unidimensional seven item scale (the Short Warwick Edinburgh Mental Well-Being Scale (SWEMWBS)) was resolved. Many items deleted because of misfit with model expectations showed considerable bias for gender. Two retained items also demonstrated bias for gender but, at the scale level, cancelled out. One further retained item 'I've been feeling optimistic about the future' showed bias for age. The correlation between the 14 item and 7 item versions was 0.954. Given fit to the Rasch model, and strict unidimensionality, SWEMWBS provides an interval scale estimate of mental well-being. Conclusion: A short 7 item version of WEMWBS was found to satisfy the strict unidimensionality expectations of the Rasch model, and be largely free of bias. This scale, SWEMWBS, provides a raw score-interval scale transformation for use in parametric procedures. In terms of face validity, SWEMWBS presents a more restricted view of mental well-being than the 14 item WEMWBS, with most items representing aspects of psychological and eudemonic well-being, and few covering hedonic well-being or affect. However, robust measurement properties combined with brevity make SWEMWBS preferable to WEMWBS at present for monitoring mental well-being in populations. Where face validity is an issue there remain arguments for continuing to collect data on the full 14 item WEMWBS

Multisensory information facilitates reaction speed by enlarging activity difference between superior colliculus hemispheres in rats

Animals can make faster behavioral responses to multisensory stimuli than to unisensory stimuli. The superior colliculus (SC), which receives multiple inputs from different sensory modalities, is considered to be involved in the initiation of motor responses. However, the mechanism by which multisensory information facilitates motor responses is not yet understood. Here, we demonstrate that multisensory information modulates competition among SC neurons to elicit faster responses. We conducted multiunit recordings from the SC of rats performing a two-alternative spatial discrimination task using auditory and/or visual stimuli. We found that a large population of SC neurons showed direction-selective activity before the onset of movement in response to the stimuli irrespective of stimulation modality. Trial-by-trial correlation analysis showed that the premovement activity of many SC neurons increased with faster reaction speed for the contraversive movement, whereas the premovement activity of another population of neurons decreased with faster reaction speed for the ipsiversive movement. When visual and auditory stimuli were presented simultaneously, the premovement activity of a population of neurons for the contraversive movement was enhanced, whereas the premovement activity of another population of neurons for the ipsiversive movement was depressed. Unilateral inactivation of SC using muscimol prolonged reaction times of contraversive movements, but it shortened those of ipsiversive movements. These findings suggest that the difference in activity between the SC hemispheres regulates the reaction speed of motor responses, and multisensory information enlarges the activity difference resulting in faster responses

Change in diet, physical activity, and body weight among young-adults during the transition from high school to college

<p>Abstract</p> <p>Background</p> <p>The freshmen year of college is likely a critical period for risk of weight gain among young-adults.</p> <p>Methods</p> <p>A longitudinal observational study was conducted to examine changes in weight, dietary intake, and other health-related behaviors among first-year college students (n = 186) attending a public University in the western United States. Weight was measured at the beginning and end of fall semester (August – December 2005). Participants completed surveys about dietary intake, physical activity and other health-related behaviors during the last six months of high school (January – June 2005) in August 2005 and during their first semester of college (August – December 2005) in December 2005.</p> <p>Results</p> <p>159 students (n = 102 women, 57 men) completed both assessments. The average BMI at the baseline assessment was 23.0 (standard deviation (SD) 3.8). Although the average amount of weight gained during the 15-week study was modest (1.5 kg), 23% of participants gained ≥ 5% of their baseline body weight. Average weight gain among those who gained ≥ 5% of baseline body weight was 4.5 kg. Those who gained ≥ 5% of body weight reported less physical activity during college than high school, were more likely to eat breakfast, and slept more than were those who did not gain ≥ 5% of body weight.</p> <p>Conclusion</p> <p>Almost one quarter of students gained a significant amount of weight during their first semester of college. This research provides further support for the implementation of education or other strategies aimed at helping young-adults entering college to achieve or maintain a healthy body weight.</p

Income Attainment among Victims of Violence: Results From a Preliminary Study

Violent victimisation may have many short-term psychological and physical outcomes. Occasionally, the negative aftermath of violence persists over time or induces other and more far-reaching consequences. Income attainment after victimisation is one of these outcomes. To date, previous studies have focussed on the income effects of violent victimisation during childhood and adolescence. Violence exposure during the early stages of the life course may frustrate processes of educational and occupational attainment and consequentially result in lower income levels. However, in addition or alternatively, many other and age-independent pathways between violent victimisation and income may be suggested. Prior studies appear to have paid little attention to this issue. Therefore, the purpose of the current study was to explore whether violent victimisation is associated with income levels several years after victimisation, irrespective of the age at which victimisation occurs. Victims of violence were recruited through the Dutch Victim Compensation Fund. To preliminary estimate the effect of violent victimisation on income, a comparable control group of non-victims was composed. The study sample contained 206 victims and 173 non-victims. Both bivariate correlational and multivariate statistical techniques suggested that violent victimisation is a significant predictor of income. Implications of the presented results were discussed with regard to future research and policy practice

Binge eating, purging and non-purging compensatory behaviours decrease from adolescence to adulthood: A population-based, longitudinal study

Background Subclinical forms of eating disorders (ED) are highly prevalent, but relatively little is known about age trends, gender differences and distinctions among symptoms. This study investigates age trends and gender difference in binge eating, purging and non-purging compensatory behaviours (CB) and the relationship of such behaviours to psychosocial problems. Methods Data from the national representative longitudinal study "Young in Norway" (ages 14-34 years) were analysed using χ 2 tests, logistic random intercept models and analyses of covariance. Results For both genders, a decrease was found in the prevalence of CB from age 14-16 years to 23 years and over. For binging, however, a significant decrease was found only for females, whose binge eating also declined more markedly over time than did males'. A significant gender difference was detected for purging, with females at higher risk. Purging was related to particularly serious symptoms of psychosocial problems: Those who purged had significantly higher levels of appearance dissatisfaction, anxiety and depressive symptoms, alcohol consumption, self-concept instability and loneliness than those with symptoms of other forms of disordered eating. Conclusions Individuals affected by purging need to be targeted as a high-risk group. The distinction in severity among the subclinical ED may indicate the need for the reformulation of the eating disorder not otherwise specified category in the Diagnostic and Statistical Manual of Mental Disorders-V

Social and occupational factors associated with psychological distress and disorder among disaster responders: a systematic review

BACKGROUND: When disasters occur, there are many different occupational groups involved in rescue, recovery and support efforts. This study aimed to conduct a systematic literature review to identify social and occupational factors affecting the psychological impact of disasters on responders. METHODS: Four electronic literature databases (MEDLINE®, Embase, PsycINFO® and Web of Science) were searched and hand searches of reference lists were carried out. Papers were screened against specific inclusion criteria (e.g. published in peer-reviewed journal in English; included a quantitative measure of wellbeing; participants were disaster responders). Data was extracted from relevant papers and thematic analysis was used to develop a list of key factors affecting the wellbeing of disaster responders. RESULTS: Eighteen thousand five papers were found and 111 included in the review. The psychological impact of disasters on responders appeared associated with pre-disaster factors (occupational factors; specialised training and preparedness; life events and health), during-disaster factors (exposure; duration on site and arrival time; emotional involvement; peri-traumatic distress/dissociation; role-related stressors; perceptions of safety, threat and risk; harm to self or close others; social support; professional support) and post-disaster factors (professional support; impact on life; life events; media; coping strategies). CONCLUSIONS: There are steps that can be taken at all stages of a disaster (before, during and after) which may minimise risks to responders and enhance resilience. Preparedness (for the demands of the role and the potential psychological impact) and support (particularly from the organisation) are essential. The findings of this review could potentially be used to develop training workshops for professionals involved in disaster response. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40359-016-0120-9) contains supplementary material, which is available to authorized users

The cost of community-managed viral respiratory illnesses in a cohort of healthy preschool-aged children

Background : Acute respiratory illnesses (ARIs) during childhood are often caused by respiratory viruses, result in significant morbidity, and have associated costs for families and society. Despite their ubiquity, there is a lack of interdisciplinary epidemiologic and economic research that has collected primary impact data, particularly associated with indirect costs, from families during ARIs in children.Methods : We conducted a 12-month cohort study in 234 preschool children with impact diary recording and PCR testing of nose-throat swabs for viruses during an ARI. We used applied values to estimate a virus-specific mean cost of ARIs.Results : Impact diaries were available for 72% (523/725) of community-managed illnesses between January 2003 and January 2004. The mean cost of ARIs was AU$309 (95$263 to $354). Influenza illnesses had a mean cost of$904, compared with RSV, $304, the next most expensive single-virus illness, although confidence intervals overlapped. Mean carer time away from usual activity per day was two hours for influenza ARIs and between 30 and 45 minutes for all other ARI categories.Conclusion : From a societal perspective, community-managed ARIs are a significant cost burden on families and society. The point estimate of the mean cost of community-managed influenza illnesses in healthy preschool aged children is three times greater than those illnesses caused by RSV and other respiratory viruses. Indirect costs, particularly carer time away from usual activity, are the key cost drivers for ARIs in children. The use of parent-collected specimens may enhance ARI surveillance and reduce any potential Hawthorne effect caused by compliance with study procedures. These findings reinforce the need for further integrated epidemiologic and economic research of ARIs in children to allow for comprehensive cost-effectiveness assessments of preventive and therapeutic options.<br /