Electrostatically-Driven Resonator on Soi with Improved Temperature Stability

This paper deals with a single-crystal-silicon (SCS) MEMS resonator with improved temperature stability. While simulations have shown that the temperature coefficient of resonant frequency can be down to 1 ppm/degrees C, preliminary measurements on non-optimised structures gave evidence of a temperature coefficient of 29 ppm/degrees C. Design, optimisation, experimental results with post process simulation and prospective work are presented.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Ground State of the Easy-Axis Rare-Earth Kagom\'e Langasite Pr3_3Ga5_5SiO14_{14}

We report muon spin relaxation ($\mu$SR) and $^{69,71}$Ga nuclear quadrupolar resonance (NQR) local-probe investigations of the kagom\'e compound Pr$_3$Ga$_5$SiO$_{14}$. Small quasi-static random internal fields develop below 40 K and persist down to our base temperature of 21 mK. They originate from hyperfine-enhanced $^{141}$Pr nuclear magnetism which requires a non-magnetic Pr$^{3+}$ crystal-field (CF) ground state. Besides, we observe a broad maximum of the relaxation rate at $\simeq 10$ K which we attribute to the population of the first excited magnetic CF level. Our results yield a Van-Vleck paramagnet picture, at variance with the formerly proposed spin-liquid ground state.Comment: minor change

Simple estimation of absolute free energies for biomolecules

One reason that free energy difference calculations are notoriously difficult in molecular systems is due to insufficient conformational overlap, or similarity, between the two states or systems of interest. The degree of overlap is irrelevant, however, if the absolute free energy of each state can be computed. We present a method for calculating the absolute free energy that employs a simple construction of an exactly computable reference system which possesses high overlap with the state of interest. The approach requires only a physical ensemble of conformations generated via simulation, and an auxiliary calculation of approximately equal central-processing-unit (CPU) cost. Moreover, the calculations can converge to the correct free energy value even when the physical ensemble is incomplete or improperly distributed. As a "proof of principle," we use the approach to correctly predict free energies for test systems where the absolute values can be calculated exactly, and also to predict the conformational equilibrium for leucine dipeptide in implicit solvent.Comment: To appear in J. Chem. Phys., 10 pages, 6 figure

Vulnerability Analysis of the MAVLink Protocol for Command and Control of Unmanned Aircraft

The MAVLink protocol is an open source, point-to-point networking protocol used to carry telemetry and to command and control many small unmanned aircraft. This research presents three exploits that compromise confidentiality, integrity, and availability vulnerabilities in the communication between an unmanned aerial vehicle and a ground control station using the MAVLink protocol. The attacks assume the configuration settings for the data-link hardware have been obtained. Field experiments using MAVProxy to compromise communication between an ArduPilot Mega 2.5 autopilot and the Mission Planner application demonstrate that all three exploits are successful when MAVLink messages are unprotected. A methodology is proposed to quantify the cost of securing the MAVLink protocol through the measurement of network latency, power consumption, and exploit success. Experimental measurements indicate that the ArduPilot Mega 2.5 autopilot running the ATmega2560 processor at 16 MHz with the standard, unsecured MAVLink protocol consumes on average 0.0105 additional watts of power per second and operates with an average additional latency of 0.11 seconds while under the most resource-intensive attack than when not under attack

Sexual Orientation Competence: Psychologists’ Perceived Competence and Relationships to Multicultural Competence, Training, Engagement, and Exposure to Lesbian, Gay, and Bisexual Individuals

Attitudes toward sexual orientation, specifically towards those who identify as lesbians, gay men, and bisexual (LGB) individuals, have varied temporally. Given the pervasiveness of heterosexism in American culture, it becomes quite important to understand if we, as psychologists, could unintentionally create heterosexist environments with our clients. This study looked at the following research question: What are the unique contributions of the predictor variables: exposure to persons of sexual minority status, training experience in sexual minority populations, perceived multicultural competence, and engagement in sexual minority specialization and practice to the criterion variable perceived sexual orientation competence within United States (US) licensed psychologists

Early life-history studies of nearshore rockfishes and lingcod off Central California, 1987-92

This study focused on the physical and biological processes that influence the distribution, abundance, growth, and survival of young-of-the-year (YOY) rockfishes and lingcod along the central California coast. The annual somatic and reproductive condition of adult female blue rockfish corresponded to annual upwelling. Resulting larval production may correspond to the reproductive potential of adults; however, ultimate recruitment success of YOY is also effected by oceanographic conditions during their planktonic stage. Within a year, each species of settled YOY was observed concurrently and in relatively similar abundances at all study dive sites along the central coast. Most species of YOY exhibited similar growth patterns among stations and years. We found a high degree of interannual variability in the condition of adults and relative abundances of YOY. We believe a large part of this variability is due to annual oceanographic conditions, specifically upwelling. Marine reserves, which would protect populations of reproductively mature rockfishes and lingcod and insure 1arval production, have been suggested as an alternative to present management strategies for these species. However, a crucial question is whether or not larvae from adult fish in reserves would significantly contribute to replenishing stocks in other areas. This study was undertaken to assist in determining the feasibility of reserves to enhance nearshore rockfish and lingcod populations. (78pp.

Challenges to Employment in Newly Emerging African Communities in Australia: A Review of the Literature

Newly emerging African communities (NEAC) in Australia face challenges in accessing employment, with consequences for both the immigrant and Australian host communities. This article presents a review of the literature on challenges to employment for NEAC in Australia. It gathers together, synthesises, and analyses previously fragmented evidence that should be used to inform social policy change and social program improvement. It focuses on African refugees and immigrants from the Horn of Africa region (Eritrea, Ethiopia, Somalia, and Sudan) who have settled in Australia in the past 10 years. The review documents the challenges to employment for this group and highlights policy and practice implications including: streamlining the qualification recognition process; introducing culturally and linguistically diverse (CALD) specialised job networks; resisting anti-NEAC sentiments, challenging stereotypes, and promoting diversity; introducing incentives to undertake volunteer work; revitalising existing English as a second language pedagogy; empowering CALD-specialised counselling services; and establishing CALD-specialised research and advocacy entities