Photoreflectance and surface photovoltage spectroscopy of beryllium-doped GaAs/AlAs multiple quantum wells

We present an optical study of beryllium delta-doped GaAs/AlAs multiple quantum well (QW) structures designed for sensing terahertz (THz) radiation. Photoreflectance (PR), surface photovoltage (SPV), and wavelength-modulated differential surface photovoltage (DSPV) spectra were measured in the structures with QW widths ranging from 3 to 20 nm and doping densities from 2×10(10) to 5×10(12) cm(–2) at room temperature. The PR spectra displayed Franz-Keldysh oscillations which enabled an estimation of the electric-field strength of ~20 kV/cm at the sample surface. By analyzing the SPV spectra we have determined that a buried interface rather than the sample surface mainly governs the SPV effect. The DSPV spectra revealed sharp features associated with excitonic interband transitions which energies were found to be in a good agreement with those calculated including the nonparabolicity of the energy bands. The dependence of the exciton linewidth broadening on the well width and the quantum index has shown that an average half monolayer well width fluctuations is mostly predominant broadening mechanism for QWs thinner than 10 nm. The line broadening in lightly doped QWs, thicker than 10 nm, was found to arise from thermal broadening with the contribution from Stark broadening due to random electric fields of the ionized impurities in the structures. We finally consider the possible influence of strong internal electric fields, QW imperfections, and doping level on the operation of THz sensors fabricated using the studied structures. © 2005 American Institute of Physic

The Chemistry of the Triterpenes and Related Compounds. Part XXXII.* The Chemistry of Hydroxyhopanone

The functional groups of hydroxyhopanone, a saturated C30H50O2 pentacyclic triterpene keto-alcohol have been characterised and a tentative structure for hydroxyhopanone is proposed

The CMS Tracker Readout Front End Driver

The Front End Driver, FED, is a 9U 400mm VME64x card designed for reading out the Compact Muon Solenoid, CMS, silicon tracker signals transmitted by the APV25 analogue pipeline Application Specific Integrated Circuits. The FED receives the signals via 96 optical fibers at a total input rate of 3.4 GB/sec. The signals are digitized and processed by applying algorithms for pedestal and common mode noise subtraction. Algorithms that search for clusters of hits are used to further reduce the input rate. Only the cluster data along with trigger information of the event are transmitted to the CMS data acquisition system using the S-LINK64 protocol at a maximum rate of 400 MB/sec. All data processing algorithms on the FED are executed in large on-board Field Programmable Gate Arrays. Results on the design, performance, testing and quality control of the FED are presented and discussed

The impact of alcohol priming on craving and motivation to drink: a meta-analysis.

Background & Aims: An initial dose of alcohol can motivate - or prime - further drinking and may precipitate (re)lapse and bingeing. Lab-based studies have investigated the alcohol priming effect. However, heterogeneity in designs has resulted in some inconsistent findings. The aims of this meta-analysis were to i) determine the pooled effect size for motivation to drink following priming, measured by alcohol consumption and craving, and ii) to examine whether design characteristics influenced any priming effect. Design: Literature searches of PsycINFO, PubMed and Scopus in October 2020 (updated October 2021) identified lab-based alcohol priming studies which assessed effect of priming on motivation to drink. Setting: Laboratory-based. Participants: Adult, alcohol users. Measurements: A tailored risk-of-bias tool assessed quality of lab-based studies. Random effects meta-analyses were computed on outcome data from 38 studies comparing the effect of a priming dose of alcohol against control on subsequent alcohol consumption/self-reported craving. Study characteristics that might have affected outcomes were design type (within/between-participant), dose of prime, time of motivation assessment, type of control drink (placebo alcohol/soft drink). Findings: A small-to-moderate effect of alcohol, relative to control, on subsequent alcohol consumption (SMD = .336 [95% CI: .171, .500) and craving (SMD = .431 [95% CI: .306, .555]). Aspects of study design differentially affected consumption and craving. The size of the priming dose had no effect on consumption, but larger doses were sometimes associated with greater craving (with craving generally following the blood alcohol curve). Alcohol priming effects for consumption, but not craving, were smaller when compared to a placebo, relative to soft drink, control. Conclusions: Lab-based alcohol priming studies are a valid paradigm from which to investigate the impact of acute intoxication on alcohol motivation. However, designs are needed which assess the impact of acute consumption on motivation to drink in more varied and realistic ways

Identifying mechanisms of youth mental health promotion:A realist evaluation of the Agenda Gap programme

Promoting youth mental health is a critical public health priority and merits robust policy and practice responses, inclusive of youth-centred and upstream interventions that address the root factors contributing to mental health outcomes. To that end, non-familial youth-adult relationships can powerfully impact youths’ healthy development, mental health and well-being, and capacities for enacting change within home, school, and policy contexts. Agenda Gap is a youth mental health promotion programme based on this principle, in which adult facilitators support youth (aged 15–24) in co-exploring activities focused on mental health promotion and policy advocacy, while fostering supportive, trusting intergenerational relationships. This study presents a realist evaluation of Agenda Gap, drawing on realist qualitative interviews with youth participants (n = 18) and adult collaborators (n = 4). We constructed 15 initial programme theories in four theoretical areas that we subsequently explored via analysis of the realist interview data. The analysis used the middle-range theories of ‘Third Space’ and ‘Third Place’ to conceptualize and articulate how causal mechanisms were produced from the non-familial youth-adult relationships that are foundational to the programme. Results are presented across 10 context-mechanism-outcome (CMO) configurations in three sections: (1) Agenda Gap Facilitation Activates ‘Third-Space/Third-Place’ Mechanisms; (2) Youth Enhance Personal Mental Health while also Supporting Mental Health of Friends and Family; (3) Youth Become Inspired and Informed to Act as Advocates and Policy Change Agents. Taken together, these findings provide insights into the important mechanisms of non-familial intergenerational trust building and demonstrate how a strengths-based conceptualization of youth mental health supports mental health maintenance, promotion, and advocacy for this population