Pulsed laser deposition growth of Fe3O4 on III–V semiconductors for spin injection

We report on the growth of thin layers of Fe3O4 on GaAs and InAs by pulsed laser deposition. It is found that Fe3O4 grows epitaxially on InAs at a temperature of 350 °C. X-ray photoelecton spectroscopy (XPS) studies of the interface show little if any interface reaction resulting in a clean epitaxial interface. In contrast, Fe3O4 grows in columnar fashion on GaAs, oriented with respect to the growth direction but with random orientation in the plane of the substrate. In this case XPS analysis showed much more evidence of interface reactions, which may contribute to the random-in-plane growth

Exploring scholarly data with Rexplore.

Despite the large number and variety of tools and services available today for exploring scholarly data, current support is still very limited in the context of sensemaking tasks, which go beyond standard search and ranking of authors and publications, and focus instead on i) understanding the dynamics of research areas, ii) relating authors ‘semantically’ (e.g., in terms of common interests or shared academic trajectories), or iii) performing fine-grained academic expert search along multiple dimensions. To address this gap we have developed a novel tool, Rexplore, which integrates statistical analysis, semantic technologies, and visual analytics to provide effective support for exploring and making sense of scholarly data. Here, we describe the main innovative elements of the tool and we present the results from a task-centric empirical evaluation, which shows that Rexplore is highly effective at providing support for the aforementioned sensemaking tasks. In addition, these results are robust both with respect to the background of the users (i.e., expert analysts vs. ‘ordinary’ users) and also with respect to whether the tasks are selected by the evaluators or proposed by the users themselves

Predictors for being physically active to keep fit and/or to lose weight after stroke: South London stroke register

Introduction: Increased physical activity and weight loss (if appropriate) after stroke is recommended for secondary prevention in the National Clinical Guidelines for Stroke (2008). However, there is a lack information about the proportion and the characteristics of stroke patients currently undertaking physical activity to keep fit and/or lose weight. Method: Data were collected from the South London Stroke Register (SLSR), a population based stroke register covering a multiethnic source population of 271,817 inhabitants (2001) in South London. Information on stroke patients’ level of physical activity was collected 12 months post stroke. Logistic regression analysis was performed to identify independent predictors for increased physical activity to keep fit and/or lose weight post stroke, including age, sex, ethnicity, stroke severity (Barthel Index) and risk factors. Results: Between Jan 2004 and December 2006, 358 first ever stroke patients were followed up 12 months post stroke. Mean age was 69, 45% were female: ethnicity was categorized as white (65%), black (25%) and other (10%).Overall, 45% of surviving stroke patients reported undertaking exercise, 25% and 1% reported exercising to keep fit and lose weight respectively, 19% reported exercising to keep fit and lose weight. In multivariate analysis, being physically active was associated with younger age (p<0.001), less severe disability (p<0.001) and black ethnicity (p<0.005). Conclusion: This study identified only one half of stroke survivors participate in physical activity at 12 months post stroke. Stroke survivors reported being physically active for different reasons but are less likely to do so to lose weight

Upper Extremity Biomechanics of Children with Spinal Cord Injury during Wheelchair Mobility

While much work is being done evaluating the upper extremity joint dynamics of adult manual wheelchair propulsion, limited work has examined the pediatric population of manual wheelchair users. Our group used a custom pediatric biomechanical model to characterize the upper extremity joint dynamics of 12 children and adolescents with spinal cord injury (SCI) during wheelchair propulsion. Results show that loading appears to agree with that of adult manual wheelchair users, with the highest loading primarily seen at the glenohumeral joint. This is concerning due to the increased time of wheelchair use in the pediatric population and the impact of this loading during developmental years. This research may assist clinicians with improved mobility assessment methods, wheelchair prescription, training, and long-term care of children with orthopaedic disabilities

Biomechanics of Pediatric Manual Wheelchair Mobility

Currently, there is limited research of the biomechanics of pediatric manual wheelchair mobility. Specifically, the biomechanics of functional tasks and their relationship to joint pain and health is not well understood. To contribute to this knowledge gap, a quantitative rehabilitation approach was applied for characterizing upper extremity biomechanics of manual wheelchair mobility in children and adolescents during propulsion, starting, and stopping tasks. A Vicon motion analysis system captured movement, while a SmartWheel simultaneously collected three-dimensional forces and moments occurring at the handrim. A custom pediatric inverse dynamics model was used to evaluate three-dimensional upper extremity joint motions, forces, and moments of 14 children with spinal cord injury (SCI) during the functional tasks. Additionally, pain and health-related quality of life outcomes were assessed. This research found that joint demands are significantly different amongst functional tasks, with greatest demands placed on the shoulder during the starting task. Propulsion was significantly different from starting and stopping at all joints. We identified multiple stroke patterns used by the children, some of which are not standard in adults. One subject reported average daily pain, which was minimal. Lower than normal physical health and higher than normal mental health was found in this population. It can be concluded that functional tasks should be considered in addition to propulsion for rehabilitation and SCI treatment planning. This research provides wheelchair users and clinicians with a comprehensive, biomechanical, mobility assessment approach for wheelchair prescription, training, and long-term care of children with SCI

Evaluation of Pediatric Manual Wheelchair Mobility Using Advanced Biomechanical Methods

There is minimal research of upper extremity joint dynamics during pediatric wheelchair mobility despite the large number of children using manual wheelchairs. Special concern arises with the pediatric population, particularly in regard to the longer duration of wheelchair use, joint integrity, participation and community integration, and transitional care into adulthood. This study seeks to provide evaluation methods for characterizing the biomechanics of wheelchair use by children with spinal cord injury (SCI). Twelve subjects with SCI underwent motion analysis while they propelled their wheelchair at a self-selected speed and propulsion pattern. Upper extremity joint kinematics, forces, and moments were computed using inverse dynamics methods with our custom model. The glenohumeral joint displayed the largest average range of motion (ROM) at 47.1° in the sagittal plane and the largest average superiorly and anteriorly directed joint forces of 6.1% BW and 6.5% BW, respectively. The largest joint moments were 1.4% body weight times height (BW × H) of elbow flexion and 1.2% BW × H of glenohumeral joint extension. Pediatric manual wheelchair users demonstrating these high joint demands may be at risk for pain and upper limb injuries. These evaluation methods may be a useful tool for clinicians and therapists for pediatric wheelchair prescription and training

Effect of the unpolarized spin state in spin-correlation measurement of two protons produced in the 12C(d,2He) reaction

In this note we discuss the effect of the unpolarized state in the spin-correlation measurement of the $^1S_0$ two-proton state produced in 12C(d,2He) reaction at the KVI, Groningen. We show that in the presence of the unpolarized state the maximal violation of the CHSH-Bell inequality is lower than the classical limit if the purity of the state is less than $\sim \verb+70$. In particular, for the KVI experiment the violation of the CHSH-Bell inequality should be corrected by a factor $\sim\verb+10$ from the pure $^1S_0$ state.Comment: 6 pages, to appear in J. Phys.

The primary cosmic ray spectrum above 10 to the 19th power eV

Progress on a re-evaluation of the spectrum of cosmic rays determined with the Haverah Park shower array is described. Particular attention is paid to the reality of some giant showers

A Comparison of Self-Control Measures and Drug and Alcohol Use among College Students

Research has shown a link between drug and alcohol behaviors and self-control; however, much of the research focuses on only the general theory of crime (Gottfredson and Hirschi 1990), without regard to Hirschi’s (2004) self-control theory. The purpose of the current study is to examine three measures of Hirschi’s self-control theory and to understand the link between Hirschi’s self-control theory and drug and alcohol behaviors. This study draws from a sample of undergraduate college students (N = 640) to examine the role of Hirschi’s self-control in the explanation of drug and alcohol behaviors. The current study uses a previous measure of Hirschi’s self-control [i.e., decisional self-control (alcohol)] and two measures (i.e., decisional self-control (cheat) and bond-based self-control) created by the researchers to analyze drug and alcohol behaviors. Results indicated that self-control based in social bonds (i.e., bond-based self-control) was significantly related to all drug and alcohol behaviors. The cost/salience scale measuring cheating behaviors [i.e., decisional self-control (cheat)] was significantly related to marijuana/hashish use, and the cost/salience scale measuring drinking and driving [i.e., decisional self-control (alcohol)] was significantly related to zero drug and alcohol behaviors. Results indicate that developing strong social bonds as a form of self-control can reduce the likelihood of drug and alcohol behaviors