Fluctuation-enhanced frequency mixing in a nonlinear micromechanical oscillator

We study noise-enhanced frequency mixing in an underdamped micromechanical torsional oscillator. The oscillator is electrostatically driven into bistability by a strong, periodic voltage at frequency $\omega_d$. A second, weak ac voltage is applied at a frequency $\omega$ close to $\omega_d$. Due to nonlinearity in the system, vibrations occur at both $\omega$ and $2\omega_d-\omega$. White noise is injected into the excitation, allowing the system to occasionally overcome the activation barrier and switch between the two states. At the primary drive frequency where the occupations of the two states are approximately equal, we observe noise-induced enhancement of the oscillation amplitudes at both $\omega$ and the down-converted frequency $2\omega_d-\omega$, in agreement with theoretical predictions. Such enhancement occurs as a result of the noise-induced interstate transitions becoming synchronous with the beating between the two driving frequencies.Comment: 4 pages 5 figure

Activation barrier scaling and crossover for noise-induced switching in a micromechanical parametric oscillator

We explore fluctuation-induced switching in a parametrically-driven micromechanical torsional oscillator. The oscillator possesses one, two or three stable attractors depending on the modulation frequency. Noise induces transitions between the coexisting attractors. Near the bifurcation points, the activation barriers are found to have a power law dependence on frequency detuning with critical exponents that are in agreement with predicted universal scaling relationships. At large detuning, we observe a crossover to a different power law dependence with an exponent that is device specific.Comment: 5 pages, 5 figure

Development of improved thermoelectric mater- ials for spacecraft applications final summary report, 29 jun. 1964 - 29 jun. 1965

Thermoelectric materials for spacecraft applications - optimization of bismuth-antimony alloys and ag-sb-fe-te-se system alloys for thermoelectric cooling in space environmen

Jesse James Syndrome

Serving Gifted Students in Rural Settings is a superb set of essays that would help practitioners in rural settings develop or enhance services for gifted students. The authors are specialists in Rural Studies, Counseling, and Gifted Education. Dr. Tamra Stambaugh is an Assistant Research Professor for Special Education and the Executive of Programs for Talented Youth at Vanderbilt University. Dr. Susannah M. Wood is an associate professor at the University of Iowa in the Department of Rehabilitation and Counselor Education. The talent of the two editors created this manual for practitioners that brings much-needed guidance for building and enhancing programs to meet the needs of gifted rural students. Leadership in rural settings is a challenge. In my own experience as a rural superintendent and principal, my talent needed to be spread across multiple roles within the district, from expertise in curriculum and instruction to not-so-strong expertise for inspecting school bus routes. Teachers are required to have talent in multiple areas as well. Each day they plan and teach multiple classes and all types of students, from a special needs child to second language learner, an average learner or a very gifted child. Education should meet the needs of all students, but without layers of support, it is a challenge

Jesse James Syndrome

Serving Gifted Students in Rural Settings is a superb set of essays that would help practitioners in rural settings develop or enhance services for gifted students. The authors are specialists in Rural Studies, Counseling, and Gifted Education. Dr. Tamra Stambaugh is an Assistant Research Professor for Special Education and the Executive of Programs for Talented Youth at Vanderbilt University. Dr. Susannah M. Wood is an associate professor at the University of Iowa in the Department of Rehabilitation and Counselor Education. The talent of the two editors created this manual for practitioners that brings much-needed guidance for building and enhancing programs to meet the needs of gifted rural students. Leadership in rural settings is a challenge. In my own experience as a rural superintendent and principal, my talent needed to be spread across multiple roles within the district, from expertise in curriculum and instruction to not-so-strong expertise for inspecting school bus routes. Teachers are required to have talent in multiple areas as well. Each day they plan and teach multiple classes and all types of students, from a special needs child to second language learner, an average learner or a very gifted child. Education should meet the needs of all students, but without layers of support, it is a challenge

Social Media and Primary Commercial Service Airports

Throughout the past decade the aviation industry in the United States has continually encountered significant socio-economic burdens. Most notable, the tragic events of September 11th left the industry highly susceptible to economic turmoil, such as the global recession accentuated by record high fuel prices, as well as sociological events like the world pandemic in the form of Severe Acute Respiratory Syndrome (SARS). The nation’s airports, the infrastructure supporting this industry, are no exception. In conjunction with these onerous events, continuing cuts in intergovernmental funding sources, as well as weakened revenue streams, have forced airports to utilize contemporary tools, strategies, and techniques to reinforce traditional management functions. Social media platforms such as blogs, Facebook, Twitter, YouTube, and Foursquare, are a growing trend throughout various public and private industries to increase effectiveness, efficiency, and overall yield in regard to marketing and communication strategies. Consistent with New Public Management and the reinvention of government in the 1980s, conducive of cost-efficiency and customer-centric approaches, airports utilize social media to increase self-sufficiency by reducing expenditures associated with traditional marketing and communication modes. In addition, social media technologies enable airports to more effectively target, engage, and foster two-way communication with a multitude of audiences. This study provides an overview of these popular social media services. This study empirically examines, both quantitatively and qualitatively, the current usage of social media throughout Primary Commercial Service airports. Statistics on airport usage, best practices and case studies are provided, supporting preliminary guidance on the use of social media at airports

Eudemonic Care: A Future Path for Occupational Therapy?

The core tenets of occupational therapy date to ancient Greece. Philosophers and physicians alike promulgated that quality of life, or “eudemonia,” is at the center of both ethical and medical concern and can be attained through healthful engagement in meaningful occupation. In more recent times, there has been a strong call to return to the powerful implementation of the eudemonic moral philosophy in health care practice, especially in occupational therapy. Searches of recent occupational therapy research show that integration of wellness initiatives into rehabilitative treatment sessions can have a profound impact on the physical and emotional healthfulness of people with a wide variety of ailments. Accordingly, we put forth three self-reflection questions and 10 client-centered questions to use in occupational therapy assessment to promote eudemonic care

Patterns and Collective Behavior in Granular Media: Theoretical Concepts

Granular materials are ubiquitous in our daily lives. While they have been a subject of intensive engineering research for centuries, in the last decade granular matter attracted significant attention of physicists. Yet despite a major efforts by many groups, the theoretical description of granular systems remains largely a plethora of different, often contradicting concepts and approaches. Authors give an overview of various theoretical models emerged in the physics of granular matter, with the focus on the onset of collective behavior and pattern formation. Their aim is two-fold: to identify general principles common for granular systems and other complex non-equilibrium systems, and to elucidate important distinctions between collective behavior in granular and continuum pattern-forming systems.Comment: Submitted to Reviews of Modern Physics. Full text with figures (2Mb pdf) avaliable at http://mti.msd.anl.gov/AransonTsimringReview/aranson_tsimring.pdf Community responce is appreciated. Comments/suggestions send to [email protected]

Robust Projections of Future Fire Probability for the Conterminous United States

Globally increasing wildfires have been attributed to anthropogenic climate change. However, providing decision makers with a clear understanding of how future planetary warming could affect fire regimes is complicated by confounding land use factors that influence wildfire and by uncertainty associated with model simulations of climate change. We use an ensemble of statistically downscaled Global Climate Models in combination with the Physical Chemistry Fire Frequency Model (PC2FM) to project changing potential fire probabilities in the conterminous United States for two scenarios representing lower (RCP 4.5) and higher (RCP 8.5) greenhouse gas emission futures. PC2FM is a physically-based and scale-independent model that predicts mean fire return intervals from both fire reactant and reaction variables, which are largely dependent on a locale\u27s climate. Our results overwhelmingly depict increasing potential fire probabilities across the conterminous US for both climate scenarios. The primary mechanism for the projected increases is rising temperatures, reflecting changes in the chemical reaction environment commensurate with enhanced photosynthetic rates and available thermal molecular energy. Existing high risk areas, such as the Cascade Range and the Coastal California Mountains, are projected to experience greater annual fire occurrence probabilities, with relative increases of 122% and 67%, respectively, under RCP 8.5 compared to increases of 63% and 38% under RCP 4.5. Regions not currently associated with frequently occurring wildfires, such as New England and the Great Lakes, are projected to experience a doubling of occurrence probabilities by 2100 under RCP 8.5. This high resolution, continental-scale modeling study of climate change impacts on potential fire probability accounts for shifting background environmental conditions across regions that will interact with topographic drivers to significantly alter future fire probabilities. The ensemble modeling approach presents a useful planning tool for mitigation and adaptation strategies in regions of increasing wildfire risk

Quality improvement, implementation, and dissemination strategies to improve mental health care for children and adolescents: a systematic review

Abstract Background Some outcomes for children with mental health problems remain suboptimal because of poor access to care and the failure of systems and providers to adopt established quality improvement strategies and interventions with proven effectiveness. This review had three goals: (1) assess the effectiveness of quality improvement, implementation, and dissemination strategies intended to improve the mental health care of children and adolescents; (2) examine harms associated with these strategies; and (3) determine whether effectiveness or harms differ for subgroups based on system, organizational, practitioner, or patient characteristics. Methods Sources included MEDLINE®, the Cochrane Library, PsycINFO, and CINAHL, from database inception through February 17, 2017. Additional sources included gray literature, additional studies from reference lists, and technical experts. Two reviewers selected relevant randomized controlled trials (RCTs) and observational studies, extracted data, and assessed risk of bias. Dual analysis, synthesis, and grading of the strength of evidence for each outcome followed for studies meeting inclusion criteria. We also used qualitative comparative analysis to examine relationships between combinations of strategy components and improvements in outcomes. Results We identified 18 strategies described in 19 studies. Eleven strategies significantly improved at least one measure of intermediate outcomes, final health outcomes, or resource use. Moderate strength of evidence (from one RCT) supported using provider financial incentives such as pay for performance to improve the competence with which practitioners can implement evidence-based practices (EBPs). We found inconsistent evidence involving strategies with educational meetings, materials, and outreach; programs appeared to be successful in combination with reminders or providing practitioners with newly collected clinical information. We also found low strength of evidence for no benefit for initiatives that included only educational materials or meetings (or both), or only educational materials and outreach components. Evidence was insufficient to draw conclusions on harms and moderators of interventions. Conclusions Several strategies can improve both intermediate and final health outcomes and resource use. This complex and heterogeneous body of evidence does not permit us to have a high degree of confidence about the efficacy of any one strategy because we generally found only a single study testing each strategy. Trial registration PROSPERO, CRD42015024759