How has big data contributed to obesity research? A review of the literature

There has been growing interest in the potential of ‘big data’ to enhance our understanding in medicine and public health. Although there is no agreed definition of big data, accepted critical components include greater volume, complexity, coverage and speed of availability. Much of these data are ‘found’ (as opposed to ‘made’), in that they have been collected for non-research purposes but could include valuable information for research. The aim of this paper is to review the contribution of ‘found’ data to obesity research to date, and describe the benefits and challenges encountered. A narrative review was conducted to identify and collate peer-reviewed research studies. Database searches conducted up to September 2017 found original studies using a variety of data types and sources. These included: retail sales, transport, geospatial, commercial weight management data, social media, and smartphones and wearable technologies. The narrative review highlights the variety of data uses in the literature: describing the built environment, exploring social networks, estimating nutrient purchases or assessing the impact of interventions. The examples demonstrate four significant ways in which ‘found’ data can complement conventional ‘made’ data: firstly, in moving beyond constraints in scope (coverage, size, and temporality); secondly, in providing objective, quantitative measures; thirdly, in reaching hard-to-access population groups; and lastly in the potential for evaluating real-world interventions. Alongside these opportunities, ‘found’ data come with distinct challenges, such as: ethical and legal questions around access and ownership; commercial sensitivities; costs; lack of control over data acquisition; validity; representativeness; finding appropriate comparators; and complexities of data processing, management and linkage. Despite widespread recognition of the opportunities, the impact of ‘found’ data on academic obesity research has been limited. The merit of such data lies not in their novelty, but in the benefits they could add over and above, or in combination with, conventionally collected data

Suboptimal Omega-3 Levels in Australian Adolescents

Design, Setting and Participants:A cross-sectional descriptive study of 251 apparently healthy adolescents (192 female, 59 male) aged 15-17 years, in year 11, from 10 schools within the Northern Sydney and Central Coast areas of New South Wales. Participants provided a morning non-fasting blood sample via finger-prick and written answers to specific demographic and lifestyle questions. Omega-3 index was calculated by adding %EPA and %DHA values in the whole blood. Equivalent erythrocyte omega-3 index values were obtained by using conversion factors (1.33 for EPA and 2.22 for DHA) from published erythrocyte/whole blood values. Main Outcome Measures: Quantitation of the individual, and estimation of the group average, blood omega-3 Index. Results:The blood omega-3 Index for this adolescent cohort ranged from 2.1-22.3 with a mean of 8.3±3.2, and median of 7.8. On average males had a higher omega-3 Index compared to females (10.5±3.7 vs 7.7±2.6, p8. Three percent had an Index of On average, adolescents from low or medium socioeconomic communities had a significantly lower omega-3 Index compared to those from higher socioeconomic neighbourhoods (mean difference=1.4, p=0.018). Overall 20% of boys and 17% of girls reported regularly taking omega-3 supplements. Regular use of omega-3 supplements was associated with a higher average omega-3 Index (9.8±3.7, n=44 compared to 8.0±3.0, n=203, p=0.001 in those not taking supplements). Conclusion:This study indicates that Australian adolescents, even when from advantaged homes, have a high probability of below optimum omega-3 levels. As reduced omega-3 levels are linked to conditions of public health concern such as diabetes, asthma and depression, targeted strategies to improve the omega-3 status in the childhood population may be warranted

The Relative Value of Measures of Omega-3 Index, Perceived Stress, Cortisol and Sleep Time in Identifying Depression Among a Cohort of Australian Adolescents

Objective: To assess the relative prognostic value of 11 variables including, omega-3, perceived stress, cortisol and sleep duration, in predicting adolescent depression. Design, Setting and Participants: A cross-sectional study of 444 healthy adolescents aged 16-18 years, from 10 schools within the Northern Sydney and Central Coast regions of New South Wales, Australia. Participants provided blood and saliva samples and completed questionnaires. Statistical classification methods were used to model the relationships between the predictors and depression. Main Outcome Measures: relative predictive value of each variable in correctly classifying depression. Results: 6% of boys and 9% of girls were categorised as experiencing severe to extremely severe depression. 4% of boys and 10% of girls were categorised as experiencing severe to extremely severe stress. The mean AM:PM cortisol for boys, 22±101, was higher than that of girls, 11±10. The average omega-3 index for boys, 10.5±3.7, was also higher than that of girls, 7.7±2.6. The average sleep duration of 7.8±1.1 hrs showed no gender differences. The best classification model identified perceived stress as the most significant predictor of depression followed by BMI and omega-3 index. Cortisol ratio was a significant discriminator for boys but not girls. When stress was excluded, shorter sleep duration became a significant discriminator in both boys and girls with waist to hip ratio providing further discrimination in girls only. Conclusion: The strongest predictor of depression in adolescents was perceived stress followed by higher BMI and lower omega-3 levels. These findings provide a rational basis for establishing program priorities for the prevention and treatment of adolescent depression

Robotics to enable older adults to remain living at home

Given the rapidly ageing population, interest is growing in robots to enable older people to remain living at home. We conducted a systematic review and critical evaluation of the scientific literature, from 1990 to the present, on the use of robots in aged care. The key research questions were as follows: (1) what is the range of robotic devices available to enable older people to remain mobile, independent, and safe? and, (2) what is the evidence demonstrating that robotic devices are effective in enabling independent living in community dwelling older people? Following database searches for relevant literature an initial yield of 161 articles was obtained. Titles and abstracts of articles were then reviewed by 2 independent people to determine suitability for inclusion. Forty-two articles met the criteria for question 1. Of these, 4 articles met the criteria for question 2. Results showed that robotics is currently available to assist older healthy people and people with disabilities to remain independent and to monitor their safety and social connectedness. Most studies were conducted in laboratories and hospital clinics. Currently limited evidence demonstrates that robots can be used to enable people to remain living at home, although this is an emerging smart technology that is rapidly evolving.<br /

Random matrix ensembles with an effective extensive external charge

Recent theoretical studies of chaotic scattering have encounted ensembles of random matrices in which the eigenvalue probability density function contains a one-body factor with an exponent proportional to the number of eigenvalues. Two such ensembles have been encounted: an ensemble of unitary matrices specified by the so-called Poisson kernel, and the Laguerre ensemble of positive definite matrices. Here we consider various properties of these ensembles. Jack polynomial theory is used to prove a reproducing property of the Poisson kernel, and a certain unimodular mapping is used to demonstrate that the variance of a linear statistic is the same as in the Dyson circular ensemble. For the Laguerre ensemble, the scaled global density is calculated exactly for all even values of the parameter $\beta$, while for $\beta = 2$ (random matrices with unitary symmetry), the neighbourhood of the smallest eigenvalue is shown to be in the soft edge universality class.Comment: LaTeX209, 17 page

Debye representation of dispersive focused waves

We report on a matrix-based diffraction integral that evaluates the focal field of any diffraction-limited axisymmetric complex system. This diffraction formula is a generalization of the Debye integral applied to apertured focused beams, which may be accommodated to broadband problems. Longitudinal chromatic aberration may limit the convenience of the Debye formulation and, additionally, spatial boundaries of validity around the focal point are provided. Fresnel number is reformulated in order to guarantee that the focal region is entirely into the region of validity of the Debye approximation when the Fresnel number of the focusing geometry largely exceeds unity. We have applied the matrix-based Debye integral to several examples. Concretely, we present an optical system for beam focusing with strong angular dispersion and free of longitudinal chromatic aberration. This simple formalism leaves an open door for analysis and design of focused beams with arbitrary angular dispersion. Our results are valid for ultrashort pulsed and polychromatic incoherent sources

Public health strategies to reduce sugar intake in the UK: an exploration of public perceptions using digital spaces

Background: To explore UK public perceptions of children’s sugar consumption, Public Health England’s Change4Life Sugar Smart App and the Soft Drinks Industry Levy, using solicited and unsolicited digital data. Methods: Data from three digital spaces were used: (1) an online questionnaire advertised on parenting forums; (2) posts to UK online parenting forums; (3) English-language Tweets from Twitter. Quantitative data were analysed using descriptive statistics and qualitative data using content and inductive thematic analysis. Results: Data were (study 1) 184 questionnaire participants; (study 2) 412 forum posts; (study 3) 618 Tweets. In study 1, 94.0% (n=173) agreed that children in the UK consumed too much sugar and this had a negative health effect (98.4%, n=181). Environments (n=135, 73.4%), media/advertising (n=112, 60.9%), and parents (n=107, 58.2%) were all reported as barriers to changing children’s sugar intake. In study 2, more posts were negative towards the Soft Drinks Industry Levy (n=189, 45.9%) than positive (n=145, 35.2%), and themes about the inability of the Levy to affect sugar consumption in children and childhood obesity emerged. Other themes related to distrust of the government, food industry and retailers. In study 3, the Sugar Smart App was viewed positively (n=474, 76.7%) with its function associated solely with identification of sugar content. Conclusions: Participants accepted the necessity of sugar reduction in children, but recognised the complexity of behaviour change. Public health activities were not always perceived as effective strategies for health promotion. There was some distrust in government, public health officials, and the food industry. A less simplistic approach to sugar reduction and more credible sources of information may, therefore, be welcomed by the public

Collective leadership dynamics among professional peers: Co-constructing an unstable equilibrium

Professional service firms (PSFs) are characterised by contingent and contested power relations among an extended group of professional peers. Studies of such firms can therefore yield important insights for the literatures on collective leadership and leader–follower relations. Yet to date PSF scholars have neglected the topic of leadership,and leadership scholars have neglected the context of PSFs.Based on 102 interviewsacross the consulting, accounting, and legal sectors, we identify three relational processesthrough which professional peers co-construct collective leadership:legitimising, negotiating, and manoeuvring. We demonstrate how the relational processes taken together constitute an unstable equilibrium, both in the moment and over time, emphasising how leadership in PSFs is inherently contested and fragile. Our model contributes to theories of collective leadership and leader–follower relations by foregrounding the power and politics thatunderlie collective leadership. We highlight the significance of the individual leader within the collective. We challengeassumptionsconcerning the binary nature of leadership and followership,by showing how colleagues may grant leadership identities to their peers without necessarily granting them leadership authority, and without claiming follower identities for themselves

Perturbative calculation of the scaled factorial moments in second-order quark-hadron phase transition within the Ginzburg-Landau description

The scaled factorial moments $F_q$ are studied for a second-order quark-hadron phase transition within the Ginzburg-Landau description. The role played by the ground state of the system under low temperature is emphasized. After a local shift of the order parameter the fluctuations are around the ground state, and a perturbative calculation for $F_q$ can be carried out. Power scaling between $F_q$'s is shown, and a universal scaling exponent $\nu\simeq 1.75$ is given for the case with weak correlations and weak self-interactions.Comment: 12 pages in RevTeX, 12 eps figure