Characteristics of multiple-island single-electron chains in relation to various factors

The characteristics of multiple-island single-electron chains are analyzed theoretically in relation to the design parameters, the materials, the background charge, and the environmental temperature with the aid of a model developed on the basis of the solution of the Poisson equation and the Monte Carlo method. It is shown that the main parameter which determines the temperature stability of the phenomenon of the Coulomb blockade is the potential-barrier height for tunneling junctions. The investigations of three systems of materials (Co-Al-O, Au-Al₂O₃, and Cr-Cr₂O₃) take shown that the multiple-island single-electron chains based on Co-Al-O are most preferable at the operating temperature. The chains based on Cr-Cr₂O₃ are less preferable.     

The generalizability of the Youth Self-Report syndrome structure in 23 societies.

As a basis for theories of psychopathology, clinical psychology and related disciplines need sound taxonomies that are generalizable across diverse populations. To test the generalizability of a statistically derived 8-syndrome taxonomic model for youth psychopathology, confirmatory factor analyses (CFAs) were performed on the Youth Self-Report (T. M. Achenbach & L. A. Rescorla, 2001) completed by 30,243 youths 11-18 years old from 23 societies. The 8-syndrome taxonomic model met criteria for good fit to the data from each society. This was consistent with findings for the parent-completed Child Behavior Checklist (Achenbach & Rescorla, 2001) and the teacher-completed Teacher's Report Form (Achenbach & Rescorla, 2001) from many societies. Separate CFAs by gender and age group supported the 8-syndrome model for boys and girls and for younger and older youths within individual societies. The findings provide initial support for the taxonomic generalizability of the 8-syndrome model across very diverse societies, both genders, and 2 age groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task rotation effects on upper extremity and back muscle activity

Job rotation is an intuitive approach to distributing work to minimize muscular fatigue. The purpose of the current study was to evaluate rotation between lifting and gripping on muscle activity and effort. Ten male participants performed all 4 combinations of two 15 min tasks in 30 min trials split between separate days to prevent fatigue. The tasks of lifting a 12 kg box and gripping at 20% of maximum were performed 6 times per minute (5 s work: 5 s rest). Muscle activity (percentiles, gaps) and perceived effort were significantly affected by the task combinations. The forearm and upper erector spinae muscles did not benefit as greatly from rotating between lifting and gripping tasks as the lower erector spinae, deltoid or trapezius. In addition to gross task differences, overlaps in muscle activity between “low back” and “upper extremity” tasks must be considered when creating effective job rotation schemes.     

Guidelines for wrist posture based on carpal tunnel pressure thresholds

OBJECTIVE: To develop work guidelines for wrist posture based on carpal tunnel pressure. Background: Wrist posture is considered a risk factor for distal upper extremity musculoskeletal disorders, and sustained wrist deviation from neutral at work may be associated with carpal tunnel syndrome. However, the physiologic basis for wrist posture guidelines at work is limited. METHODS: The relationship of wrist posture to carpal tunnel pressure was examined in 37 healthy participants. The participants slowly moved their wrists in extension-flexion and radioulnar deviation while wrist posture and carpal tunnel pressure were recorded. The wrist postures associated with pressures of 25 and 30 mmHg were identified for each motion and used to determine the 25th percentile wrist angles (the angles that protect 75% of the study population from reaching a pressure of 25 or 30 mmHg). RESULTS: Using 30 mmHg, the 25th percentile angles were 32.7 degrees (95% confidence interval [CI] = 27.2-38.1 degrees) for wrist extension, 48.6 degrees (37.7 -59.4 degrees) for flexion, 21.8 degrees (14.7-29.0 degrees) for radial deviation, and 14.5 degrees (9.6-19.4 degrees) for ulnar deviation. For 25 mmHg, the 25th percentile angles were 26.6 degrees and 37.7 degrees for extension and flexion, with radial and ulnar deviation being 17.8 degrees and 12.1 degrees, respectively. CONCLUSION: Further research can incorporate the independent contributions of pinch force and finger posture into this model. APPLICATION: The method presented can provide wrist posture guidelines for the design of tools and hand-intensive tasks.     

Subthreshold voltage‐induced transferred charge measurements of evaporated ZnS:Mn alternating‐current thin‐film electroluminescent devices

Subthreshold voltage‐induced transferred charge (VIQ) analysis is proposed as a novel method for assessing the nature of aging in alternating‐current thin‐film electroluminescent (ACTFEL) devices. VIQ analysis involves the application of 20,000 bipolar voltage pulses of variable amplitude and measurement of the subthreshold charge transferred in the phosphor for voltage amplitudes from 0 V to threshold. VIQ experiments provide information related to the physical location, density, energy depth, and capture cross‐section of phosphor traps responsible for ACTFEL device aging. VIQ aging experiments were performed on ZnS:Mn ACTFEL devices whose phosphor layers were deposited by thermal evaporation, atomic layer epitaxy using chlorine as a constituent of the precursor gas [ALE (Cl)], and atomic layer epitaxy with diethyl zinc as a precursor gas [ALE (DEZ)]. The depth of the traps responsible for VIQ in evaporated, ALE (Cl), and ALE (DEZ) ZnS:Mn are estimated to be ～1.0–1.2, ～0.3, and ～0.7–0.9 eV, respectively. It is speculated that the traps responsible for VIQ are due to sulfur vacancies, chlorine, and oxygen, for evaporated, ALE (Cl), and ALE (DEZ), respectively.     

Canada's national aquatic biological specimen bank and database

Long-term systematic storage of environmental specimens has become an important component of formal environmental monitoring programs in many countries. In 1977, the Contaminants Surveillance Program (CSP) began in the Great Lakes Basin. In support of the CSP, Fisheries and Oceans Canada began archiving fish tissue samples and created the Great Lakes Fisheries Specimen Bank (GLFSB). In 2006, responsibility for the GLFSB was transferred to Environment Canada and it was renamed the National Aquatic Biological Specimen Bank (NABSB). The new name better reflects the current contents and purpose of the specimen bank which now supports Canada's Chemicals Management Plan (CMP). The NABSB employs standardized banking protocols, computerized sample tracking, maintenance of all data and metadata associated with each specimen, and modern storage equipment situated in a dedicated facility at the Canada Centre for Inland Waters in Burlington, Ontario. Since 1977, specimens from the NABSB have contributed to more than 60 scientific publications, reports, and/or book chapters on the status, trends, and bioaccumulation of metals and various organic contaminants such as PCBs, dioxins, furans, and aromatic hydrocarbons, in aquatic ecosystems. Collection and archiving of specimens in the NABSB continues such that the specimen bank currently holds more than 52,000 samples from 18,749 specimens of top predator fish, forage fish, plankton, and other invertebrates collected over 32 years of environmental monitoring in the Canadian waters of the Great Lakes and beyond.     

Consideration of the “island” background charge in single-electron transistor simulation

Three approximations of the “island” background charge are described within the proposed 2D numerical model of the metal single-electron transistor. These approximations fit the experimental data well when calculating I–V characteristics of single-electron transistors according to the model developed in many cases. The validity of these approximations is exemplified by specific calculations of I–V characteristics.     

The effect of typing posture on wrist extensor muscle loading

High static loading of the forearm extensor musculature has been observed during keying tasks. To reduce the level of loading, one must first understand the contributing factors. A simulation of the human finger was used to determine muscle force contributions during a static index finger key press at several wrist postures. The planar model included active and passive muscle forces of the intrinsic and extrinsic finger muscles. The model was expanded to include the passive forces from the other fingers as well as the weight of the hand to determine the exertion required of the wrist extensor muscles to maintain the given wrist and finger postures. Model results indicated that greater than 25% of maximal exertion is required of the wrist extensors when the wrist is extended to 30. The increased moment contribution from passive forces of the extrinsic finger flexor muscles was responsible for the majority of the increased wrist extensor contribution as the wrist was extended. These findings are in relative agreement with previous electromyographic studies and may indicate a mechanism for forearm extensor pain in office workers. Potential applications of this research include ergonomic modeling of the upper limb to determine internal loads that may lead to work-related disorders.