The energy budget of GRBs based on updated prompt \& afterglow observations

We compare the isotropic equivalent 15-2000 keV gamma-ray energy, E_gamma, emitted by a sample of 91 swift Gamma-Ray Bursts (GRBs) with known redshifts, with the isotropic equivalent fireball energy, E_fb, as estimated within the fireball model framework from X-ray afterglow observations of these bursts. The uncertainty in E_gamma, which spans the range of ~10^51 erg to ~10^53.5 erg, is approximately 25% on average, due mainly to the extrapolation from the BAT detector band to the 15-2000 keV band. The uncertainty in E_fb is approximately a factor of 2, due mainly to the X-ray measurements' scatter. We find E_gamma and E_fb to be tightly correlated. The average(std) of {\eta}^11hr_gamma is approximately log_10(E_gamma/(3{\epsilon} _eE^11hr_fb)) are -0.34(0.60), and the upper limit on the intrinsic spread of {\eta}_gamma is approximately 0.5 ({\epsilon}_e is the fraction of shocked plasma energy carried by electrons and E^x hr_fb is inferred from the X-ray flux at x hours). We also find that E_fb inferred from X-ray observations at 3 and 11 hours are similar, with an average(std) of log_10(E^3hr_fb/E^11hr_fb) of 0.04(0.28). The small variance of {\eta}_gamma implies that burst-to-burst variations in {\epsilon}_e and in the efficiency of fireball energy conversion to gamma-rays are small, and suggests that both are of order unity. The small variance of {\eta}_gamma and the similarity of E^3hr_fb and E^11hr_fb further imply that {\epsilon}_e does not vary significantly with shock Lorentz factor, and that for most bursts the modification of fireball energy during the afterglow phase, by processes such as radiative losses or extended duration energy injection, are not significant. Finally, our results imply that if fireballs are indeed jets, then the jet opening angle satisfies {\theta}>0.1 for most cases. [abridged]Comment: An expanded discussion of the absence of energy injection and 'flat X-ray phases' in the majority of burst

Power System Stability Assessment with Supervised Machine Learning

Power system stability assessment has become an important area of research due to the increased penetration of photovoltaics (PV) in modern power systems. This work explores how supervised machine learning can be used to assess power system stability for the Western Electricity Coordinating Council (WECC) service region as part of the Data-driven Security Assessment for the Multi-Timescale Integrated Dynamics and Scheduling for Solar (MIDAS) project. Data-driven methods offer to improve power flow scheduling through machine learning prediction, enabling better energy resource management and reducing demand on real-time time-domain simulations. Frequency, transient, and small signal stability datasets were created using the 240-bus and reduced 18-bus models of the WECC system. Supervised machine learning was performed to predict the system’s frequency nadir, critical clearing time, and damping ratio, respectively. In addition to varying algorithm hyperparameters, experiments were performed to evaluate model prediction performance through various data entry methods, data allocation methods during model development, and preprocessing techniques. This work also begins analysis of Electric Reliability Council of Texas (ERCOT) grid behavior during extreme frequency events, and provides suggestions for potential supervised machine learning applications in the future. Timestamped frequency event data is collected every 100 milliseconds from Frequency Disturbance Recorders (FDRs) installed in the ERCOT service territory by the Power Information Technology Laboratory at the University of Tennessee, Knoxville. The data is filtered, and the maximum Rate of Change of Frequency (ROCOF) is calculated using the windowing technique. Trends in data are evaluated, and ROCOF prediction performance is verified against another ROCOF calculation technique

Physical activity among Latino children in London, Ontario: An assessment of physical activity levels, sedentary behaviours, and physical activity-related barriers and facilitators

The purpose of the study was to assess the physical activity (PA) levels, sedentary behaviours, and PA-related barriers and facilitators of a sample of Latino children in London, Canada. Forty boys and 34 girls (mean age = 11.4 years) completed questionnaires related to PA levels, sedentary behaviours, and PA-related barriers and facilitators, and 64 of these children wore an accelerometer for 4 consecutive days. Children spent an average of 53 minutes per day in moderate-to-vigorous PA. The average daily sedentary time for participants was 8.6 hours, and subjective measures revealed that participants spent 3.8 hours per day in front of screens. Participants identified a number of barriers to PA, including environmental factors, a lack of resources, reduced opportunities for PA, a lack of motivation, and a lack of time. PA-related facilitators included motivation, opportunities for skill development, social support, and physical fitness goals

Solving for Affordability in the San Francisco Housing Crisis: Is California’s Regional Housing Needs Allocation (RHNA) the Answer?

Over the last two decades San Francisco has been suffering from a worsening housing shortage and affordability crisis, as housing production has lagged far behind job growth in the city and the region. As San Francisco’s housing market is especially supply constrained due to its unique geography, long-standing zoning laws, and convoluted permitting process, it is especially difficult to add the needed housing at an acceptable rate. Overall, this housing crisis has affected middle and lower income households the most as many have been forced to relocate due to rapidly increasing rents. In an attempt to stimulate housing production state lawmakers have chosen to use the Regional Housing Needs Allocation (RHNA) process as a way to require cities like San Francisco to plan for and build more housing, especially at affordable levels. This process, which runs on eight year cycles, sees the state allocate mandated housing goals for each city via regional government entities. Due to a series of housing legislation packages passed in recent years at the state level the RHNA process was given more ‘teeth’ via increased allocations, enforcement, and accountability. As such, for the next RHNA cycle, running from 2023 to 2030, San Francisco is required to show the state that it can facilitate the construction of over 82,000 units in eight years with 57% of these units affordable to ‘very low’ to ‘moderate’ income groups. This will require San Francisco to make significant policy changes, including rezoning much of the city to accommodate for increased density. If the city fails to do this it will lose substantial funding for affordable housing production as well as certain controls over its local planning process. While this new RHNA process will force up-zoning and land use deregulation in San Francisco there is no guarantee that the required housing will ever get built. To build the over 46,500 units of affordable housing allocated over the next eight years, 5,800 units of affordable housing will need to be built each year. For reference, in San Francisco 5,000 units of total housing (both market-rate and affordable) have only been built in one of the last twenty years (2016), and over the last ten years the average number of affordable units built per year was 874 units. In addition, San Francisco is currently lacking the necessary funding to meet its targets since the City is projected to need $19 billion to build the required affordable housing over the next RHNA cycle. While the new RHNA process may help address the overall housing supply shortage in the long run, without significant additional state funding and new revenue streams San Francisco will fall well short of its affordable housing goals, meaning the revamped RHNA process will do little to solve the ongoing affordability crisis

Healthy and Happy: Creating and Evaluating a Catalyst to Improve the Health of University Students via an Online Training System

Increasingly, university students are facing unique, significant physical and mental health challenges. Additionally, they are spending more and more of their time online and are using online platforms to access mental health resources; consequently, there is a timely opportunity to explore the potential of online happiness interventions, specifically with video, to improve happiness among university students. Evidence suggests that improved happiness relates to improved physical health, mental health, and academic outcomes. The purpose of this research was to test if an online happiness intervention, using videos to boost happiness, can increase self-reported happiness among university students. The primary outcome was self-reported happiness, and secondary outcomes included self-reported lifestyle measures such as weight, confidence in goal setting abilities, satisfaction with accomplishing daily tasks, exercise, sleep, stress, tobacco use, illicit drug use, alcohol consumption, social issues, number of close friends, leisure activities, and gratitude. Additionally, feedback regarding the online program and video modules was collected. A total of 114 students participated in this four-week, online study. Data were collected through online self-report questionnaires. Comparisons of pre and post scores on the primary and secondary outcomes measures were conducted and qualitative feedback about the video was collected. Evaluation consisted of online self-report questionnaires. This study demonstrated that not only are students interested in participating in online programs to boost self-reported happiness, but it is also possible to increase the self-reported happiness of university student via online videos. All five measures used to assess self-reported happiness revealed an increase in scores over the duration of the study; the increase was statistically significant for four of the five measures (p \u3c 0.05). An analysis to examine the characteristics of those who dropped out of the study from those who completed the study add additional support to the evidence that screening and sub-categorizing participants prior to an intervention in an effort to increase engagement and to meet the unique needs of individuals with particularly characteristics, may be efficacious and may increase retention. The results provide new, valuable information to add to the body of work that suggests that happiness interventions may improve the self-reported happiness of undergraduate university students

Socioeconomic Aspects of Small-Scale Commercial Fisheries Development in the Republic of the Marshall Islands

This study examines the sociocultural aspects of fishery development in the Republic of the Marshall Islands. It is based upon field research conducted through interviews with indigenous fisherfolk, business people, and expatriates. The Marshall Islands were selected because they have a limited economic base, yet have abundant fishery resources which have considerable potential to generate foreign exchange. Many studies focus on the technical aspects of fishery resource development. However, none address the sociocultural factors that influence its success. This thesis demonstrates that several aspects of Marshallese fishing society, some of which correspond to characteristics of the peasantry identified by Rogers (1969), can impede small-scale fisheries development at both individual and institutional levels. Understanding these aspects may help the RMI to more effectively develop its fisheries

Disembodied intersubjectivity. Social networks, space and experience

This paper is a preliminary account of my research on the connections between social networks and space. In the first place I will try to show how the introduction of space and time concepts can give some new ideas to network research enabling us, at the same time, to look at spatio-temporal modifications in a more concrete and operative way. On this purpose three important meanings of space, having different explanatory powers, are discussed: space as a constraint, space as a frame organising social relations, and space as a form of experience. Secondly I will suggest the concept of intersubjectivity as a possible interesting outcome of networks and space and time approach partnership. In particular I will briefly discuss how the link between networks and experience (in their relation with space) can be an interesting field of application of this challenging and controversial concept. Keywords: space; time; social networks; intersubjectivit

Changes in Disability-Free Life Expectancy in Canada between 1994 and 2007

Life expectancy at birth continues to increase in Canada, reaching 81.2 years in 2009. Knowing whether these older years are healthy or disabled is critical for policymakers. We examine changes in disability-free life expectancy for men and women in Canada in 1994 and 2007 using the Sullivan method. We find that increases in life expectancy for men were due to a moderate increase in healthy years and a larger increase in disabled years. The increases in life expectancy for women were driven almost completely by increases in disabled years, suggesting an “expansion of morbidity” among women