Incentivizing Exploration with Heterogeneous Value of Money

Recently, Frazier et al. proposed a natural model for crowdsourced exploration of different a priori unknown options: a principal is interested in the long-term welfare of a population of agents who arrive one by one in a multi-armed bandit setting. However, each agent is myopic, so in order to incentivize him to explore options with better long-term prospects, the principal must offer the agent money. Frazier et al. showed that a simple class of policies called time-expanded are optimal in the worst case, and characterized their budget-reward tradeoff. The previous work assumed that all agents are equally and uniformly susceptible to financial incentives. In reality, agents may have different utility for money. We therefore extend the model of Frazier et al. to allow agents that have heterogeneous and non-linear utilities for money. The principal is informed of the agent's tradeoff via a signal that could be more or less informative. Our main result is to show that a convex program can be used to derive a signal-dependent time-expanded policy which achieves the best possible Lagrangian reward in the worst case. The worst-case guarantee is matched by so-called "Diamonds in the Rough" instances; the proof that the guarantees match is based on showing that two different convex programs have the same optimal solution for these specific instances. These results also extend to the budgeted case as in Frazier et al. We also show that the optimal policy is monotone with respect to information, i.e., the approximation ratio of the optimal policy improves as the signals become more informative.Comment: WINE 201

Uptake and effectiveness of the Children's Fitness Tax Credit in Canada: the rich get richer

<p>Abstract</p> <p>Background</p> <p>The Government of Canada implemented a Children's Fitness Tax Credit (CFTC) in 2007 which allows a non-refundable tax credit of up to $500 to register a child in an eligible physical activity (PA) program. The purposes of this study were to assess whether the awareness, uptake, and perceived effectiveness of this tax credit varied by household income among Canadian parents.</p> <p>Methods</p> <p>An internet-based panel survey was conducted in March 2009 with a representative sample of 2135 Canadians. Of those, parents with children aged 2 to 18 years of age (<it>n </it>= 1004) were asked if their child was involved in organized PA programs (including dance and sports), the associated costs to register their child in these programs, awareness of the CFTC, if they had claimed the CFTC for the tax year 2007, and whether they planned to claim it in the upcoming year. Parents were also asked if they believed the CFTC has lead to their child being more involved in PA programs.</p> <p>Results</p> <p>Among parents, 54.4% stated their child was in organized PA and 55.5% were aware of the CFTC. Parents in the lowest income quartile were significantly less aware and less likely to claim the CFTC than other income groups. Among parents who had claimed the CFTC, few (15.6%) believed it had increased their child's participation in PA programs.</p> <p>Conclusions</p> <p>More than half of Canadian parents with children have claimed the CFTC. However, the tax credit appears to benefit the wealthier families in Canada.</p

Infographic. One small step for man, one giant leap for men's health: a meta-analysis of behaviour change interventions to increase men's physical activity.

OBJECTIVE:To determine the effects of behaviour change interventions on men's physical activity (postintervention), sustained change in physical activity behaviour (≥12 months postintervention) and to identify variations in effects due to potential moderating variables (eg, theoretical underpinning, gender-tailored, contact frequency). DESIGN:Systematic review with meta-analysis. Pooled effect size (Cohen's d) was calculated assuming a random-effects model. Homogeneity and subsequent exploratory moderator analyses were assessed using Q, T2 and I2. DATA SOURCES:Medline, EMBASE, CINAHL, SportDiscus and Web of Science to April 2019. ELIGIBILITY CRITERIA FOR SELECTED STUDIES:Randomised control trials of behaviour change interventions in men (≥18 years) where physical activity was an outcome and data were from men-only studies or disaggregated by sex. RESULTS:Twenty-six articles described 24 eligible studies. The overall mean intervention effect on men's physical activity was 0.35 (SE=0.05; 95% CI 0.26 to 0.45; p<0.001). This effect size is consistent with an increase of approximately 97 min of total physical activity per week or 980 steps per day. Intervention moderators associated with greater increases in physical activity included objective physical activity outcome measures, a gender-tailored design, use of a theoretical framework, shorter length programmes (≤12 weeks), using four or more types of behaviour change techniques and frequent contact with participants (≥1 contact per week). 12 studies included additional follow-up assessments (≥12 months postintervention) and the overall mean effect was 0.32 (SE=0.09; 95% CI 0.15 to 0.48; p<0.001) for that sustained increase in physical activity. SUMMARY:Behaviour change interventions targeting men's physical activity can be effective. Moderator analyses are preliminary and suggest research directions

Turning the Tide from Cars to Active Transport: Policy Recommendations for New Zealand

Background: Despite national-level efforts to encourage active transport in New Zealand since 2005, rates of active transport have continued to decline in most parts of the country, with negative impacts on health and the environment. / Purpose: We describe the development of key policy recommendations for active transport in New Zealand as an outcome of multi-sectoral discussions held at The Active Living and Environment Symposium (TALES; www.otago.ac.nz/active-living-2019; Dunedin, New Zealand; February 2019). The goal was to establish a set of priority recommendations to inform active transport decision-making in central and local government, public health units and regional sports trusts in New Zealand. / Project Description: The development of recommendations was planned and led by a working group consisting of ten TALES symposium delegates working in academia, industry and non-governmental organisations with prior work experience in central/local government and the private sector. Symposium delegates provided input prior to the symposium (delegates submitted 1-3 policy recommendations); during the symposium (delegates challenged/discussed/modified the first draft of recommendations at a dedicated final day session); and after the symposium (delegates provided feedback on the second draft of recommendations and associated actions). Using an online survey, the working group members also independently evaluated importance and feasibility of each recommended action before inclusion in the document. The final 13 recommendations (and 39 associated actions) were grouped across four broad categories: A) Evaluation, governance and funding; B) Education and encouragement/promotion; C) Engineering (infrastructure, built environment); and D) Enforcement and regulations. The report aligns with the New Zealand government’s increased focus on wellbeing, walking, cycling, public transport and Vision Zero approach, and recommends national targets for walking, cycling and public transport by 2050. The report was officially launched in April 2019. Initial discussions of recommendations with relevant stakeholders were conducted in four major urban centres in April-May 2019. / Conclusions: This cross-sector effort resulted in a report that has the potential to stimulate the development of a new active transport strategy for New Zealand; prompt setting of targets and monitoring progress/outcomes; and inform New Zealand’s response to the World Health Organization’s Global Action Plan on Physical Activity 2018-2030. Key policy recommendations for active transport in New Zealand include: making a national-level commitment to change; establishing a nationally coordinated and funded programme of education and promotion of active transport; creating a commitment to design cities for people and not for cars; and developing a regulatory system that encourages the use of active transport

Development of key policy recommendations for active transport in New Zealand: A multi-sector and multidisciplinary endeavour

Background: Despite national-level initiatives to encourage active transport (AT) in New Zealand since 2005, rates of AT have continued to decline in most parts of the country, with negative impacts on health and the environment. This article describes the development of key policy recommendations for increasing AT in New Zealand. The goal was to establish a cohesive set of priority recommendations to inform AT decision-making in central and local government, district health boards, public health units and regional sports trusts in New Zealand. Project description: The development of policy recommendations was a planned outcome of multi-sectoral discussions held at The Active Living and Environment Symposium (TALES; Dunedin, New Zealand; February 2019). A ten-member working group consisting of TALES symposium delegates working in academia, industry and non-governmental organisations led the development of the recommendations. Symposium delegates contributed their expertise to draft recommendations and reports prior to, during and after the symposium. Importance and feasibility of each recommended action were independently evaluated by working group members. The final set of 13 policy recommendations (and 39 associated actions) included: making a national-level commitment to change; establishing a nationally coordinated and funded programme of education and promotion of AT; making a commitment to design cities for people, not cars; and developing a regulatory system that encourages AT. The report aligns with the current New Zealand government's increased focus on wellbeing, walking, cycling, public transport and the Vision Zero approach. A final report was officially launched in April 2019 with presentations to stakeholders April-May 2019. Conclusions: This cross-sector effort resulted in a report with a set of recommendations designed to stimulate the development of a new AT strategy for New Zealand; prompt setting of targets and monitoring progress/outcomes; and inform New Zealand's response to the World Health Organization's Global Action Plan on Physical Activity 2018–2030

Imaging and Dynamics of Light Atoms and Molecules on Graphene

Observing the individual building blocks of matter is one of the primary goals of microscopy. The invention of the scanning tunneling microscope [1] revolutionized experimental surface science in that atomic-scale features on a solid-state surface could finally be readily imaged. However, scanning tunneling microscopy has limited applicability due to restrictions, for example, in sample conductivity, cleanliness, and data aquisition rate. An older microscopy technique, that of transmission electron microscopy (TEM) [2, 3] has benefited tremendously in recent years from subtle instrumentation advances, and individual heavy (high atomic number) atoms can now be detected by TEM [4 - 7] even when embedded within a semiconductor material [8, 9]. However, detecting an individual low atomic number atom, for example carbon or even hydrogen, is still extremely challenging, if not impossible, via conventional TEM due to the very low contrast of light elements [2, 3, 10 - 12]. Here we demonstrate a means to observe, by conventional transmision electron microscopy, even the smallest atoms and molecules: On a clean single-layer graphene membrane, adsorbates such as atomic hydrogen and carbon can be seen as if they were suspended in free space. We directly image such individual adatoms, along with carbon chains and vacancies, and investigate their dynamics in real time. These techniques open a way to reveal dynamics of more complex chemical reactions or identify the atomic-scale structure of unknown adsorbates. In addition, the study of atomic scale defects in graphene may provide insights for nanoelectronic applications of this interesting material.Comment: 9 pages manuscript and figures, 9 pages supplementary informatio

Mtss1 promotes cell-cell junction assembly and stability through the small GTPase Rac1

Cell-cell junctions are an integral part of epithelia and are often disrupted in cancer cells during epithelial-to-mesenchymal transition (EMT), which is a main driver of metastatic spread. We show here that Metastasis suppressor-1 (Mtss1; Missing in Metastasis, MIM), a member of the IMD-family of proteins, inhibits cell-cell junction disassembly in wound healing or HGF-induced scatter assays by enhancing cell-cell junction strength. Mtss1 not only makes cells more resistant to cell-cell junction disassembly, but also accelerates the kinetics of adherens junction assembly. Mtss1 drives enhanced junction formation specifically by elevating Rac-GTP. Lastly, we show that Mtss1 depletion reduces recruitment of F-actin at cell-cell junctions. We thus propose that Mtss1 promotes Rac1 activation and actin recruitment driving junction maintenance. We suggest that the observed loss of Mtss1 in cancers may compromise junction stability and thus promote EMT and metastasis

Proximity to Sports Facilities and Sports Participation for Adolescents in Germany

Objectives - To assess the relationship between proximity to specific sports facilities and participation in the corresponding sports activities for adolescents in Germany. Methods - A sample of 1,768 adolescents aged 11–17 years old and living in 161 German communities was examined. Distances to the nearest sports facilities were calculated as an indicator of proximity to sports facilities using Geographic Information Systems (GIS). Participation in specific leisure-time sports activities in sports clubs was assessed using a self-report questionnaire and individual-level socio-demographic variables were derived from a parent questionnaire. Community-level socio-demographics as covariates were selected from the INKAR database, in particular from indicators and maps on land development. Logistic regression analyses were conducted to examine associations between proximity to the nearest sports facilities and participation in the corresponding sports activities. Results - The logisitic regression analyses showed that girls residing longer distances from the nearest gym were less likely to engage in indoor sports activities; a significant interaction between distances to gyms and level of urbanization was identified. Decomposition of the interaction term showed that for adolescent girls living in rural areas participation in indoor sports activities was positively associated with gym proximity. Proximity to tennis courts and indoor pools was not associated with participation in tennis or water sports, respectively. Conclusions - Improved proximity to gyms is likely to be more important for female adolescents living in rural areas

Using ordinal logistic regression to evaluate the performance of laser-Doppler predictions of burn-healing time

Background Laser-Doppler imaging (LDI) of cutaneous blood flow is beginning to be used by burn surgeons to predict the healing time of burn wounds; predicted healing time is used to determine wound treatment as either dressings or surgery. In this paper, we do a statistical analysis of the performance of the technique. Methods We used data from a study carried out by five burn centers: LDI was done once between days 2 to 5 post burn, and healing was assessed at both 14 days and 21 days post burn. Random-effects ordinal logistic regression and other models such as the continuation ratio model were used to model healing-time as a function of the LDI data, and of demographic and wound history variables. Statistical methods were also used to study the false-color palette, which enables the laser-Doppler imager to be used by clinicians as a decision-support tool. Results Overall performance is that diagnoses are over 90% correct. Related questions addressed were what was the best blood flow summary statistic and whether, given the blood flow measurements, demographic and observational variables had any additional predictive power (age, sex, race, % total body surface area burned (%TBSA), site and cause of burn, day of LDI scan, burn center). It was found that mean laser-Doppler flux over a wound area was the best statistic, and that, given the same mean flux, women recover slightly more slowly than men. Further, the likely degradation in predictive performance on moving to a patient group with larger %TBSA than those in the data sample was studied, and shown to be small. Conclusion Modeling healing time is a complex statistical problem, with random effects due to multiple burn areas per individual, and censoring caused by patients missing hospital visits and undergoing surgery. This analysis applies state-of-the art statistical methods such as the bootstrap and permutation tests to a medical problem of topical interest. New medical findings are that age and %TBSA are not important predictors of healing time when the LDI results are known, whereas gender does influence recovery time, even when blood flow is controlled for. The conclusion regarding the palette is that an optimum three-color palette can be chosen 'automatically', but the optimum choice of a 5-color palette cannot be made solely by optimizing the percentage of correct diagnoses