Relaxation of strained silicon on Si0.5Ge0.5 virtual substrates

Strain relaxation has been studied in tensile strained silicon layers grown on Si0.5Ge0.5 virtual substrates, for layers many times the critical thickness, using high resolution x-ray diffraction. Layers up to 30 nm thick were found to relax less than 2% by the glide of preexisting 60° dislocations. Relaxation is limited because many of these dislocations dissociate into extended stacking faults that impede the dislocation glide. For thicker layers, nucleated microtwins were observed, which significantly increased relaxation to 14%. All these tensile strained layers are found to be much more stable than layers with comparable compressive strain

Discussing sudden unexpected death in epilepsy: Are we empowering our patients? A questionnaire survey

OBJECTIVE: To examine patient knowledge about sudden unexpected death in epilepsy (SUDEP) compared to other risks in epilepsy. To explore patients' experiences surrounding SUDEP disclosure and opinions on how information should be delivered. DESIGN: A cross-sectional questionnaire. SETTING: Royal Free Hospital, London outpatient epilepsy clinics. PARTICIPANTS: New and follow-up patients attending epilepsy clinics at a London teaching hospital over six months. Patients identified as being at risk of suffering negative emotional or psychological consequences of SUDEP discussions were excluded. MAIN OUTCOME MEASURES: Patient knowledge about epilepsy risks; patient opinion regarding source, timing and delivery of SUDEP information; impact on health seeking behaviour. RESULTS: Ninety-eight per cent of patients were aware of medication adherence, 84% of factors influencing seizure frequency, 78% of driving regulations, 50% of SUDEP and 38% of status epilepticus; 72% of patients felt that SUDEP information should be given to all patients. Preferences for timing of SUDEP discussions varied between those wanting information at diagnosis (40%) and those preferring to receive it after three clinic appointments (18%) to avoid information overload at the first consultation. Emotional responses (48% positive, 38% negative) predominated over measurable behavioural change following SUDEP discussions. CONCLUSIONS: Less than half the patients knew about SUDEP and status epilepticus. Although the majority of patients with epilepsy wish to be informed about SUDEP early on in their diagnosis, information must be delivered in a way that promotes patient knowledge and empowerment

Multidirectional In Vivo Characterization of Skin Using Wiener Nonlinear Stochastic System Identification Techniques

A triaxial force-sensitive microrobot was developed to dynamically perturb skin in multiple deformation modes, in vivo. Wiener static nonlinear identification was used to extract the linear dynamics and static nonlinearity of the force–displacement behavior of skin. Stochastic input forces were applied to the volar forearm and thenar eminence of the hand, producing probe tip perturbations in indentation and tangential extension. Wiener static nonlinear approaches reproduced the resulting displacements with variances accounted for (VAF) ranging 94–97%, indicating a good fit to the data. These approaches provided VAF improvements of 0.1–3.4% over linear models. Thenar eminence stiffness measures were approximately twice those measured on the forearm. Damping was shown to be significantly higher on the palm, whereas the perturbed mass typically was lower. Coefficients of variation (CVs) for nonlinear parameters were assessed within and across individuals. Individual CVs ranged from 2% to 11% for indentation and from 2% to 19% for extension. Stochastic perturbations with incrementally increasing mean amplitudes were applied to the same test areas. Differences between full-scale and incremental reduced-scale perturbations were investigated. Different incremental preloading schemes were investigated. However, no significant difference in parameters was found between different incremental preloading schemes. Incremental schemes provided depth-dependent estimates of stiffness and damping, ranging from 300 N/m and 2 Ns/m, respectively, at the surface to 5 kN/m and 50 Ns/m at greater depths. The device and techniques used in this research have potential applications in areas, such as evaluating skincare products, assessing skin hydration, or analyzing wound healing.Foundation for Research, Science & Technology (N.Z.) (Grants UOA21647.001 and NERF 9077/3608892)Tertiary Education Commission of New Zealand (Medical Technologies Centre of Research Excellence (MedTech CoRE)

Origins of the sarsen megaliths at Stonehenge

The sources of the stone used to construct Stonehenge around 2500 BCE have been debated for over four centuries. The smaller “bluestones” near the center of the monument have been traced to Wales, but the origins of the sarsen (silcrete) megaliths that form the primary architecture of Stonehenge remain unknown. Here, we use geochemical data to show that 50 of the 52 sarsens at the monument share a consistent chemistry and, by inference, originated from a common source area. We then compare the geochemical signature of a core extracted from Stone 58 at Stonehenge with equivalent data for sarsens from across southern Britain. From this, we identify West Woods, Wiltshire, 25 km north of Stonehenge, as the most probable source area for the majority of sarsens at the monument

Willow Creek, California Tourism Analysis

The primary objective of this study was to introduce and recommend different strategies for the city of Willow Creek, California to increase tourism post-Covid-19. After extensive research, the report outlines various opportunities that the Recreation 365 class, Tourism Industry Management, believe will help Willow Creek in their efforts to attract their target audience

'It’d be useful, but I wouldn’t use it':barriers to university students’ feedback seeking and recipience

For feedback to be effective, it must be used by the receiver. Prior research has outlined numerous reasons why students’ use of feedback is sometimes limited, but there has been little systematic exploration of these barriers. In 11 activity-oriented focus groups, 31 undergraduate Psychology students discussed how they use assessment feedback. The data revealed many barriers that inhibit use of feedback, ranging from students’ difficulties with decoding terminology, to their unwillingness to expend effort. Thematic analysis identified four underlying psychological processes: awareness, cognisance, agency, and volition. We argue that these processes should be considered when designing interventions to encourage students’ engagement with feedback. Whereas the barriers identified could all in principle be removed, we propose that doing so would typically require – or would at least benefit from – a sharing of responsibility between teacher and student. The data highlight the importance of training students to be proactive receivers of feedback

Measurement of Tidal Form Drag Using Seafloor Pressure Sensors

As currents flow over rough topography, the pressure difference between the up-and downstream sides results in form drag-a force that opposes the flow. Measuring form drag is valuable because it can be used to estimate the loss of energy from currents as they interact with topography. An array of bottom pressure sensors was used to measure the tidal form drag on a sloping ridge in 200 m of water that forms a 1-km headland at the surface in Puget Sound, Washington. The form drag per unit length of the ridge reached 1 x 10⁴ N m⁻¹ during peak flood tides. The tidally averaged power removed from the tidal currents by form drag was 0.2 W m⁻², which is 30 times larger than power losses to friction. Form drag is best parameterized by a linear wave drag law as opposed to a bluff body drag law because the flow is stratified and both internal waves and eddies are generated on the sloping topography. Maximum turbulent kinetic energy dissipation rates of 5 x 10⁻⁵ W kg⁻¹ were measured with a microstructure profiler and are estimated to account for 25%-50% of energy lost from the tides. This study is among the first to measure form drag directly using bottom pressure sensors. The measurement and analysis techniques presented here are suitable for periodically reversing flows because they require the removal of a time-mean signal. The advantage of this technique is that it delivers a continuous record of form drag and is much less ship intensive compared to previous methods for estimation of the bottom pressure field.Keywords: Stratified flow, Rough topography, Lee Waves, Ocean, Nonlinear internal waves, Headland, Conversion, Dissipation, Slope, Generatio