Improvement of the 3ω\omega thermal conductivity measurement technique at nanoscale

The reduction of the thermal conductivity in nanostructures opens up the possibility of exploiting for thermoelectric purposes also materials such as silicon, which are cheap, available and sustainable but with a high thermal conductivity in their bulk form. The development of thermoelectric devices based on these innovative materials requires reliable techniques for the measurement of thermal conductivity on a nanometric scale. The approximations introduced by conventional techniques for thermal conductivity measurements can lead to unreliable results when applied to nanostructures, because heaters and temperature sensors needed for the measurement cannot have a negligible size, and therefore perturb the result. In this paper we focus on the 3$\omega$ technique, applied to the thermal conductivity measurement of suspended silicon nanomembranes. To overcome the approximations introduced by conventional analytical models used for the interpretation of the 3$\omega$ data, we propose to use a numerical solution, performed by means of finite element modeling, of the thermal and electrical transport equations. An excellent fit of the experimental data will be presented, discussed, and compared with an analytical model

Thermal conductivity of silicon nanowire forests

A large amount of parallel silicon nanowires, placed perpendicularly to a silicon substrate (silicon nanowire forests), have been contacted and assembled in order to fabricate legs of a thermoelectric generator. This paper reports the measurement of the main parameter for thermoelectric applications, which is the thermal conductivity. The reported value, which confirms the strong reduction of the thermal conductivity in nanostructures, is measured on a large amount (>107) of parallel nanowires with a diameter variable in the range 60-120 nm, and takes into account eventual non-uniformities which are unavoidable on surfaces of several mm2. As silicon nanowire forests are very thin, it has been necessary to develop a suitable measurement apparatus. The fabrication of devices based on silicon nanowire forests, the apparatus and the measurement procedure, as well as the the results, are illustrated and discussed

The Willingness of U.S. Emergency Medical Technicians to Respond to Terrorist Incidents

A nationally representative sample of basic and paramedic emergency medical service providers in the United States was surveyed to assess their willingness to respond to terrorist incidents. EMTs were appreciably (9-13%) less willing than able to respond to such potential terrorist-related incidents as smallpox outbreaks, chemical attacks, or radioactive dirty bombs (p < 0.0001). EMTs who had received terrorism-related continuing medical education within the previous 2 years were twice as likely (OR = 1.9, 95% CI 1.9, 2.0) to be willing to respond to a potential smallpox dissemination incident as those who indicated that they had not received such training. Timely and appropriate training, attention to interpersonal concerns, and instilling a sense of duty may increase first medical provider response rates

Preparing Health Professions Students for Terrorism, Disaster, and Public Health Emergencies: Core Competencies

The recent increased threat of terrorism, coupled with the ever-present dangers posed by natural disasters and public health emergencies, clearly support the need to incorporate bioterrorism preparedness and emergency response material into the curricula of every health professions school in the nation. A main barrier to health care preparedness in this country is a lack of coordination across the spectrum of public health and health care communities and disciplines. Ensuring a unified and coordinated approach to preparedness requires that benchmarks and standards be consistent across health care disciplines and public health, with the most basic level being education of health professions students. Educational competencies establish the foundation that enables graduates to meet occupational competencies. However, educational needs for students differ from the needs of practitioners. In addition, there must be a clear connection between departments of public health and all other health care entities to ensure proper preparedness. The authors describe both a process and a list of core competencies for teaching emergency preparedness to students in the health care professions, developed in 2003 and 2004 by a team of experts from the four health professions schools of Columbia University in New York City. These competencies are directly applicable to medical, dental, nursing, and public health students. They can also easily be adapted to other health care disciplines, so long as differences in levels of proficiency and the need for clinical competency are taken into consideration

Effectiveness of bystander naloxone administration and overdose education programs: a meta-analysis

The objective of this review was to assess the effectiveness of bystander naloxone administration and overdose education programs by synthesizing quantitative results reported in the research literature. Studies meeting predefined criteria were identified and reviewed, and their results were synthesized through meta-analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for overdose recoveries for individuals who received naloxone dispensed by non-medical community members, and the standardized mean difference was calculated for test scores of non-medical volunteers who received training in overdose management versus the scores of untrained volunteers. Pooled data from four studies showed that naloxone administration by bystanders was associated with a significantly increased odds of recovery compared with no naloxone administration (OR = 8.58, 95% CI = 3.90 to 13.25). Data from five studies of overdose education indicated that average scores were significantly higher for trained participants than untrained participants for tests on naloxone administration, overdose recognition, and overdose response (standardized mean difference = 1.35, 95% CI = 0.92 to 1.77). Empirical evidence in the research literature suggests that bystander naloxone administration and overdose education programs are associated with increased odds of recovery and with improved knowledge of overdose recognition and management in non-clinical settings

Association of the Safe Routes to School program with school-age pedestrian and bicyclist injury risk in Texas

Background Safe Routes to School (SRTS) is a federally funded transportation program for facilitating physically active commuting to and from school in children through improvements of the built environment, such as sidewalks, bicycle lanes, and safe crossings. Although it is evident that SRTS programs increase walking and bicycling in school-age children, their impact on pedestrian and bicyclist injury has not been adequately examined. Methods We analyzed quarterly traffic crash data between January 2008 and June 2013 in Texas to assess the effect of the SRTS program implemented after 2009 on school-age pedestrian and bicyclist injuries. Results The annualized rates of pedestrian and bicyclist injuries between pre- and post-SRTS periods declined 42.5% (95% confidence interval (CI) 39.6% to 45.4%) in children aged 5 to 19 years and 33.0% (95% CI 30.5% to 35.5%) in adults aged 30 to 64 years. Negative binomial modeling revealed that SRTS intervention was associated with a 14% reduction in the school-age pedestrian and bicyclist injury incidence rate ratio (IRR 0.86, 95% CI 0.75 to 0.98). The effect of the SRTS intervention on pedestrian and bicyclist fatalities was similar though smaller in magnitude and was not statistically significant (adjusted IRR 0.90, 95% CI 0.67 to 1.21). Conclusions These results indicate that the implementation of the SRTS program in Texas may have contributed to declines in school-age pedestrian and bicyclist injuries

Preparing for disasters: What should you know, and when should you know it?

Three waves of terrorism have ushered in a new era in public health, safety, and health care in the United States: The February 26, 1993 explosions at New York's World Trade Center, the April 19, 1995 bombing at the Murrah Federal Building in Oklahoma City, and the September 11, 2001 attacks, along with the anthrax cases that followed. Those events have awakened federal, state, and local governments to the urgency of improving their disaster-response capabilities. The health professions have also stepped forward to delineate the roles of their members in disasters, establish minimum competencies, and develop new training programs. Physician assistants have a strong tradition of responding to crisis. In all likelihood, PAs will be among the first responders to any disaster in the United States. It is incumbent on the profession and on individual PAs to understand what their roles would be in a disaster and to prepare accordingly

Cultural and economic complementarities of spatial agglomeration in the British television broadcasting industry: Some explorations.

This paper considers the processes supporting agglomeration in the British television broadcasting industry. It compares and contrasts the insights offered by the cultural turn in geography and more conventionally economic approaches. It finds that culture and institutions are fundamental to the constitution of production and exchange relationships and also that they solve fundamental economic problems of coordinating resources under conditions of uncertainty and limited information. Processes at a range of spatial scales are important, from highly local to global, and conventional economics casts some light on which firms are most active and successful

With a little help from my friends: An analysis of the role of social support in digital inequalities

This article reports an empirical study on the composition and socio-economic background of social support networks and their moderating role in explaining digital inequalities. It conceptually draws upon and empirically reaffirms Van Dijk’s multiple access model, acknowledging motivational, material, skill and usage divides, while focussing on the under-researched issue of social support as indispensible source of social learning. Besides a small group of self-reliants, the results indicate a pattern of relatively socially disadvantaged domestic support receivers, characterized by lower digital resources. A second social support pattern points to a relatively socially advantaged non-domestic support receivers (i.e. friends/colleagues), high in digital resources. Drawing upon the concept of homophily in social networks, the results indicate a link between offline and online exclusion, perpetuating digital inequalities