High-performance Schottky diodes endure high temperatures

Fabrication process and aluminum/GaAs (gallium arsenide) coupling are used to produce Schottky diodes that have high cutoff frequencies and can withstand operating temperatures in excess of 500 C

The covid-19 learning crisis as a challenge and an opportunity for schools: An evidence review and conceptual synthesis of research-based tools for sustainable change

This paper advances our understanding of how schools can become change agents capable of transforming local practice to address the challenges arising from the Covid-19 pandemic. It presents a novel application of cultural-historical activity theory to reinterpret evidence on widespread learning loss and increasing educational inequities resulting from the pandemic, and to identify scalable transformative learning opportunities through reframing the crisis as a double stimulation. By reviewing evidence of the emerging educational landscape, we first develop a picture of the new ‘problem space’ upon which schools must act. We develop a problem space map to serve as the first stimulus to articulate local challenges. Integrating this problem space with research on professional change, we identify conceptual tools to capture learning gaps and implement pedagogic interventions at scale, in order to enhance schools’ agency in directly addressing the crisis. These tools can act as the second stimulus, enabling educators to address local challenges. We conclude by discussing the Covid-19 educational crisis as a unique stimulus for professional learning and outline the potential for durable shifts in educational thinking and practice beyond the pandemic. We argue that this unprecedented historic disruption can be harnessed as a transformative professional learning opportunity. In particular, we consider how research on professional change offers local, scalable interventions and tools that can support educators in preventing the new insights from ‘slipping away’ post-pandemic. Utilising the notions of boundaries and tool-mediated professional change, we examine the ways in which this disruption generates opportunities to envision alternative futures for equitable learning in school.Author 1: The epiSTEMe project [grant number RES-179-25-0003, PI Prof. K. Ruthven] The TEACh project [ES/M005445/1, PI Prof. P. Rose] ESRC Impact Acceleration Grant, University of Cambridge [PI Dr. R. Hofmann] Cambridge University Health Partners Commonwealth Education Trust (PI. Prof. S. Hennessy) Authors 2-8: (2) Faculty of Education, University of Cambridge, PhD scholarship (3) Economic and Social Research Council PhD scholarship [ES/P000738/1] (4) Agencia Nacional de Investigación y Desarrollo (ANID), Cambridge Trust, PhD scholarship (5) Economic and Social Research Council [ES/P000738/1] and MRC Epidemiology Unit PhD scholarship (6) Yayasan Khazanah, Cambridge Trust, PhD scholarship (7) Guy’s and St Thomas’ Charity, UK [TCF180902] PhD scholarship (8) The LEGO Foundatio

Roughening of the (1+1) interfaces in two-component surface growth with an admixture of random deposition

We simulate competitive two-component growth on a one dimensional substrate of $L$ sites. One component is a Poisson-type deposition that generates Kardar-Parisi-Zhang (KPZ) correlations. The other is random deposition (RD). We derive the universal scaling function of the interface width for this model and show that the RD admixture acts as a dilatation mechanism to the fundamental time and height scales, but leaves the KPZ correlations intact. This observation is generalized to other growth models. It is shown that the flat-substrate initial condition is responsible for the existence of an early non-scaling phase in the interface evolution. The length of this initial phase is a non-universal parameter, but its presence is universal. In application to parallel and distributed computations, the important consequence of the derived scaling is the existence of the upper bound for the desynchronization in a conservative update algorithm for parallel discrete-event simulations. It is shown that such algorithms are generally scalable in a ring communication topology.Comment: 16 pages, 16 figures, 77 reference

Abundances of Red Giants in the Andromeda II Dwarf Spheroidal Galaxy

We have obtained spectra for 50 candidate red giants in Andromeda II (a dwarf spheroidal companion of M31) using LRIS on the Keck II telescope. After eliminating background galaxies and Galactic foreground stars, we are left with a sample of 42 red giants for which membership in Andromeda II can be established unambiguously from radial velocities. Line indices measured on the Lick/IDS system are combined with V and I photometry obtained with the Keck II and Palomar 5m telescopes to investigate the age and metallicity distribution of these stars. Based on a comparison of the measured line indices to those of Lick/IDS standard stars in globular and open clusters, we derive a mean metallicity of [Fe/H] = -1.47+/-0.19 dex. This confirms earlier conclusions based on Thuan-Gunn gr photometry that Andromeda II obeys the familiar relation between mean stellar metallicity and galaxy luminosity. There is also evidence for a dispersion in metallicity of 0.35+/-0.10 dex based on the scatter in the measured Mgb line indices and the observed width of the galaxy's giant branch. Although existing observations of Local Group dwarf galaxies indicate that their mean stellar metallicity depends rather sensitively on host galaxy absolute magnitude, the internal spread in metallicity appears to be relatively independent of luminosity. Finally, a small number of stars are found above the Population II red giant branch, indicating the presence of a modest intermediate-age population in this galaxy. (ABRIDGED)

Mental health in UK Biobank - development, implementation and results from an online questionnaire completed by 157 366 participants: a reanalysis

Background UK Biobank is a well-characterised cohort of over 500 000 participants including genetics, environmental data and imaging. An online mental health questionnaire was designed for UK Biobank participants to expand its potential. Aims Describe the development, implementation and results of this questionnaire. Method An expert working group designed the questionnaire, using established measures where possible, and consulting a patient group. Operational criteria were agreed for defining likely disorder and risk states, including lifetime depression, mania/hypomania, generalised anxiety disorder, unusual experiences and self-harm, and current post-traumatic stress and hazardous/harmful alcohol use. Results A total of 157 366 completed online questionnaires were available by August 2017. Participants were aged 45–82 (53% were ≥65 years) and 57% women. Comparison of self-reported diagnosed mental disorder with a contemporary study shows a similar prevalence, despite respondents being of higher average socioeconomic status. Lifetime depression was a common finding, with 24% (37 434) of participants meeting criteria and current hazardous/harmful alcohol use criteria were met by 21% (32 602), whereas other criteria were met by less than 8% of the participants. There was extensive comorbidity among the syndromes. Mental disorders were associated with a high neuroticism score, adverse life events and long-term illness; addiction and bipolar affective disorder in particular were associated with measures of deprivation. Conclusions The UK Biobank questionnaire represents a very large mental health survey in itself, and the results presented here show high face validity, although caution is needed because of selection bias. Built into UK Biobank, these data intersect with other health data to offer unparalleled potential for crosscutting biomedical research involving mental health

A Comparison of Elemental Abundance Ratios in Globular Clusters, Field Stars, and Dwarf Spheroidal Galaxies

We have compiled a sample of globular clusters with high quality stellar abundances from the literature to compare to the chemistries of stars in the Galaxy and those in dwarf spheroidal galaxies. Of the 45 globular clusters examined, 29 also have kinematic information. Most of the globular clusters belong to the Galactic halo, however a signficant number have disk kinematics or belong to the bulge. Focusing on the [alpha/Fe] and light r-process element ratios, we find that most globular cluster stars mimic those of the field stars of similar metallicities, and neither clearly resembles the presently available stellar abundances in the dwarf galaxies (including the globular clusters in the Large Magellanic Cloud). The exceptions to these general elemental ratio comparisons are already known in the literature, e.g., omega Centauri, Palomar 12, and Terzan 7 associated with the Sagittarius remnant, and Ruprecht 106 which has a high radial velocity and low [alpha/Fe] ratio. A few other globular clusters show more marginal peculiarities. The most notable one being the halo cluster M68 which has a high Galactocentric rotational velocity, a slightly younger age, and a unique [Si/Ti] ratio. The [Si/Ti] ratios decrease with increasing [Fe/H] at intermediate metallicities, which is consistent with very massive stars playing a larger role in the early chemical evolution of the Galaxy. The chemical similarities between globular clusters and field stars with [Fe/H]<-1.0 suggests a shared chemical history in a well mixed early Galaxy. The differences to the published chemistries of stars in the dwarf spheroidal galaxies suggests that neither the globular clusters, halo stars, nor thick disk stars had their origins in small isolated systems like the present-day Milky Way dwarf satellites.Comment: 24 pages, including 10 figures (8 are in color) and 4 tables; Accepted for publication in the Astronomical Journa

Fact and fiction in housing research: utilizing the creative imagination

As much of our conceptual framework is informed by the experience of the imagination, there is much to be learnt from a study of various creative forms. Narrative fiction can be one such form, allowing us to gain a useful insight into complex features of social life. The purpose of this article is to investigate the treatment of housing issues in contemporary literature in order to gain insights into attitudes, experiences and interpretations from the perspective of a broad cultural milieu. Discussions of professionalism, housing tenure and homelessness have tended to be conducted within a narrow framework and adopted orthodox modes of evaluation. Consequently, the neglect of housing within a wider cultural context has reinforced the isolation of housing issues. The article argues that although discussions of housing and housing policy have been seriously limited within the contemporary novel, there are a number of key insights that can be gained from a discussion of issues within a fictional setting