Type-II InAsxSb1-x/InAs quantum dots for midinfrared applications: Effect of morphology and composition on electronic and optical properties

InSb-based self-assembled quantum dots are very promising for the midinfrared (3-5μm) optical range. We have analyzed the effect of geometry and composition on the electronic structure and optical spectra of InAsx Sb1-x /InAs dots. The calculated transition energies agree well with the available experimental data. The results show that the geometry of the dot can be estimated from the optical spectra if the composition is known, and vice versa. © 2009 The American Physical Society

Simulation of the Interactions Between Gamma-Rays and Detectors Using BSIMUL

Progress made during 1995 on the Monte-Carlo gamma-ray spectrum simulation program BSIMUL is discussed. Several features have been added, including the ability to model shield that are tapered cylinders. Several simulations were made on the Near Earth Asteroid Rendezvous detector

Progress report for the Monte-Carlo gamma-ray spectrum simulation program BSIMUL

The progress made during 1995 on the Monte-Carlo gamma-ray spectrum simulation program BSIMUL is discussed. Several features have been added, including the ability to model shields that are tapered cylinders. Several simulations were made on the Near Earth Asteroid Rendezvous detector

Space Velocities of L- and T-type Dwarfs

(Abridged) We have obtained radial velocities of a sample of 18 ultracool dwarfs (M6.5-T8) using high-resolution, near-infrared spectra obtained with NIRSPEC and the Keck II telescope. We have confirmed that the radial velocity of Gl 570 D is coincident with that of the K-type primary star Gl 570 A, thus providing additional support for their true companionship. The presence of planetary-mass companions around 2MASS J05591914-1404488 (T4.5V) has been analyzed using five NIRSPEC radial velocity measurements obtained over a period of 4.37 yr. We have computed UVW space motions for a total of 21 L and T dwarfs within 20 pc of the Sun. This population shows UVW velocities that nicely overlap the typical kinematics of solar to M-type stars within the same spatial volume. However, the mean Galactic (44.2 km/s) and tangential (36.5 km/s) velocities of the L and T dwarfs appear to be smaller than those of G to M stars. A significant fraction (~40%) of the L and T dwarfs lies near the Hyades moving group (0.4-2 Gyr), which contrasts with the 10-12% found for earlier-type stellar neighbors. Additionally, the distributions of all three UVW components (sigma_{UVW} = 30.2, 16.5, 15.8 km/s) and the distributions of the total Galactic (sigma_{v_tot} = 19.1 km/s) and tangential (sigma_{v_t} = 17.6 km/s) velocities derived for the L and T dwarf sample are narrower than those measured for nearby G, K, and M-type stars, but similar to the dispersions obtained for F stars. This suggests that, in the solar neighborhood, the L- and T-type ultracool dwarfs in our sample (including brown dwarfs) is kinematically younger than solar-type to early M stars with likely ages in the interval 0.5-4 Gyr.Comment: Accepted for publication in Ap

Impact of social prescribing to address loneliness: a mixed methods evaluation of a national social prescribing programme

Loneliness is considered a global public health issue because of its detrimental impact on physical and mental health but little is known about which interventions can reduce loneliness. One potential intervention is social prescribing, where a link worker helps service‐users to access appropriate support such as community activities and social groups. Some qualitative studies have identified that social prescribing may help to reduce service‐users’ loneliness. Given this, the British Red Cross (a third sector organisation) developed and delivered a national social prescribing service in the United Kingdom to support people who were experiencing, or at risk of, loneliness. Service‐users could receive up to 12 weeks of support from a link worker. A mixed methods study was conducted to understand the impact of the support on loneliness, and to identify the facilitators and barriers to service delivery. The study included: (a) analysis of quantitative data collected routinely between May 2017 and December 2019 (n = 10,643) including pre‐post analysis of UCLA data (n = 2,250) and matched comparator work to measure changes in loneliness; (b) semi‐structured interviews with service‐users, link workers and volunteers (n = 60) and (c) a Social Return on Investment Analysis. The majority of the service‐users (72.6%, n = 1634/2250) felt less lonely after receiving support. The mean change in UCLA score was −1.84 (95% CI −1.91 to −1.77) of a maximum change of 6.00 (decrease indicates an improvement). Additional benefits included improved wellbeing, increased confidence and life having more purpose. The base case analysis estimated a social return on investment of £3.42 per £1 invested in the service. Having skilled link workers and support tailored to individual needs appeared key. However, challenges included utilising volunteers, meeting some service‐users’ needs in relation to signposting and sustaining improvements in loneliness. Nonetheless, the service appeared successful in supporting service‐users experiencing loneliness

The ATLAS SCT grounding and shielding concept and implementation

This paper presents a complete description of Virgo, the French-Italian gravitational wave detector. The detector, built at Cascina, near Pisa (Italy), is a very large Michelson interferometer, with 3 km-long arms. In this paper, following a presentation of the physics requirements, leading to the specifications for the construction of the detector, a detailed description of all its different elements is given. These include civil engineering infrastructures, a huge ultra-high vacuum (UHV) chamber (about 6000 cubic metres), all of the optical components, including high quality mirrors and their seismic isolating suspensions, all of the electronics required to control the interferometer and for signal detection. The expected performances of these different elements are given, leading to an overall sensitivity curve as a function of the incoming gravitational wave frequency. This description represents the detector as built and used in the first data-taking runs. Improvements in different parts have been and continue to be performed, leading to better sensitivities. These will be detailed in a forthcoming paper

Planning intervention using dynamic assessments: A case study

Dynamic assessments (DA) of language have been shown to be a useful addition to the battery of tests used to diagnose language impairments in children, and to evaluate their skills. The current article explores the value of the information gained from a DA in planning intervention for a child with language impairment. A single case study was used to demonstrate the detailed qualitative information that can be derived from a DA procedure, and how that information may be used to elicit greater gains from intervention. The participant was a boy, aged 9, with a previously diagnosed language impairment. He was receiving language therapy regularly in a language resource base attached to his school. The CELF-3(UK) was used to monitor changes in his language, before and after two periods of intervention. The initial baseline phase consisted of regular ongoing language therapy. The second phase of therapy was modified by the speech and language therapist after receiving a report of the child’s performance on the Dynamic Assessment of Sentence Structure (DASS; Hasson et al., 2012), and observations of the child’s metalinguistic and metacognitive awareness. Greater gains observed in the second phase of therapy reflected the good modifiability shown by the child’s performance on the DASS

Co-Occurrence and Characteristics of Patients With Axial Spondyloarthritis Who Meet Criteria for Fibromyalgia Results From a UK National Register

Objective. To estimate the proportion of patients with axial spondyloarthritis (SpA) in a UK national biologics registry who met criteria for fibromyalgia (FM), and to delineate the characteristics of these patients. Methods. Two cohorts of patients are prospectively recruited from across 83 centers in the UK for the British Society for Rheumatology Biologics Register in Ankylosing Spondylitis (BSRBR-AS). All patients are required to meet Assessment of SpondyloArthritis international Society (ASAS) criteria for axial SpA. Patients are either newly starting biologic therapy (biologics cohort) or are naive to treatment with biologic agents (non-biologics cohort) at the time of recruitment, and all patients are followed up prospectively. At recruitment and follow-up, clinical information and measurements are recorded while patients complete the 2011 research criteria for FM and assessments of the level of disease activity and work impact. Results. Of the patients registered in the BSRBR-AS, 1,504 (68% male) were eligible for the current analysis, of whom 311 (20.7%) met the 2011 research criteria for FM. Prevalence of FM was similar between patients who fulfilled the modified New York criteria for AS (19.7%) and those who fulfilled ASAS imaging criteria but not the modified New York criteria (25.2%); however, among those who fulfilled only the ASAS clinical criteria, the prevalence of FM was lower (9.5%). Patients who met FM criteria reported significantly worse disease activity, function, global severity scores, and quality of life, and were more likely to have moderate or severe levels of mood disorder and clinically important fatigue. Patients who met FM criteria reported experiencing work impairment around half their working time. Meeting FM criteria was not related to elevated C-reactive protein levels or most extraspinal manifestations, but was associated with a higher likelihood of having received biologic therapy. Conclusion. Developing management approaches that would address the significant unmet clinical needs of the 1 in 5 patients with axial SpA who meet criteria for FM should be a research priority

Applicability of the kp method to modeling of InAs/GaSb short-period superlattices

We investigate the long-standing controversy surrounding modeling of the electronic spectra of InAs/GaSb short-period superlattices (SPSLs). Most commonly, such modeling for semiconductor heterostructures is based on the kp method. However, this method has so far failed to predict the band structure for type-II InAs/GaSb SPSLs. Instead, it has systematically overestimated the energy gap between the electron and heavy-hole minibands, which led to the suggestion that the kp method is inadequate for these heterostructures. Our results show that the physical origin of the discrepancy between modeling and experimental results may be the graded and asymmetric InAs/GaSb interface profile. We have performed band-structure modeling within the kp method using a realistic interface profile based on experimental observations. Our calculations show good agreement with experimental data, both from our own measurements and from the published literature. © 2009 The American Physical Society