1,579 research outputs found
Libraries need standards
The article discusses the need for standards in the library and information science profession, such as the use of the Dewey Decimal System of classification or the Dublin Core metadata scheme which facilitate information organization and library orientation. The most fundamental area in which standards are used is in the description and identification of objects. The author argues that the increasingly high number of electronic and Web-based information resources necessitates a universal set of standards for such material
Modelling Gaia CCD pixels with Silvaco 3D engineering software
Gaia will only achieve its unprecedented measurement accuracy requirements
with detailed calibration and correction for radiation damage. We present our
Silvaco 3D engineering software model of the Gaia CCD pixel and two of its
applications for Gaia: (1) physically interpreting supplementary buried channel
(SBC) capacity measurements (pocket-pumping and first pixel response) in terms
of e2v manufacturing doping alignment tolerances; and (2) deriving electron
densities within a charge packet as a function of the number of constituent
electrons and 3D position within the charge packet as input to microscopic
models being developed to simulate radiation damage.Comment: 4 pages, 3 figures, contributed poster, appearing in proceedings of
the ELSA conference: Gaia, at the frontiers of astrometry, 7-11 June 2010,
S\`evres, Pari
Social isolation, loneliness and physical performance in older-adults: fixed effects analyses of a cohort study
Isolation and loneliness are related to various aspects of health. Physical performance is a central component of health. However, its relationship with isolation and loneliness is not well understood. We therefore assessed the relationship between loneliness, different aspects of social isolation, and physical performance over time. 8,780 participants from the English Longitudinal Study of Ageing, assessed three times over 8 years of follow-up, were included. Measures included physical performance (Short Physical Performance Battery), loneliness (modified UCLA Loneliness Scale), and isolation considered in three ways (domestic isolation, social disengagement, low social contact). Fixed effects regression models were used to estimate the relationship between changes in these parameters. Missing data were imputed to account for variable response and ensure a representative sample. Loneliness, domestic isolation and social disengagement were longitudinally associated with poorer physical performance when accounting for both time-invariant and time-variant confounders (loneliness: coef = - 0.06, 95% CI - 0.09 to - 0.02; domestic isolation: coef = - 0.32, 95% CI - 0.46 to - 0.19; social disengagement: coef = - 0.10, 95% CI - 0.12 to - 0.07). Low social contact was not associated with physical performance. These findings suggest social participation and subjectively meaningful interpersonal interactions are related to physical performance, and highlight additional considerations regarding social distancing related to COVID-19 control measures
Control of polarization and mode mapping of small volume high Q micropillars
We show that the polarization of the emission of a single quantum dot embedded within a microcavity pillar of elliptical cross section can be completely controlled and even switched between two orthogonal linear polarizations by changing the coupling of the dot emission with the polarized photonic modes. We also measure the spatial profle of the emission of a series of pillars with
different ellipticities and show that the results can be well described by simple theoretical modeling
of the modes of an infinite length elliptical cylinder
Electrode level Monte Carlo model of radiation damage effects on astronomical CCDs
Current optical space telescopes rely upon silicon Charge Coupled Devices
(CCDs) to detect and image the incoming photons. The performance of a CCD
detector depends on its ability to transfer electrons through the silicon
efficiently, so that the signal from every pixel may be read out through a
single amplifier. This process of electron transfer is highly susceptible to
the effects of solar proton damage (or non-ionizing radiation damage). This is
because charged particles passing through the CCD displace silicon atoms,
introducing energy levels into the semi-conductor bandgap which act as
localized electron traps. The reduction in Charge Transfer Efficiency (CTE)
leads to signal loss and image smearing. The European Space Agency's
astrometric Gaia mission will make extensive use of CCDs to create the most
complete and accurate stereoscopic map to date of the Milky Way. In the context
of the Gaia mission CTE is referred to with the complementary quantity Charge
Transfer Inefficiency (CTI = 1-CTE). CTI is an extremely important issue that
threatens Gaia's performances. We present here a detailed Monte Carlo model
which has been developed to simulate the operation of a damaged CCD at the
pixel electrode level. This model implements a new approach to both the charge
density distribution within a pixel and the charge capture and release
probabilities, which allows the reproduction of CTI effects on a variety of
measurements for a large signal level range in particular for signals of the
order of a few electrons. A running version of the model as well as a brief
documentation and a few examples are readily available at
http://www.strw.leidenuniv.nl/~prodhomme/cemga.php as part of the CEMGA java
package (CTI Effects Models for Gaia).Comment: Accepted by MNRAS on 13 February 2011. 15 pages, 7 figures and 5
table
Use of tobacco and e-cigarettes among youth in Great Britain in 2022: analysis of a cross sectional survey
Introduction: Although e-cigarettes can be an effective form of nicotine substitution for adults attempting to quit smoking, their use among children and young people is a concern. Accurate data about this are needed to inform debates over policy and regulation in the UK and elsewhere. Methods: Using data from an online survey of 2613 youth aged 11–18 years, conducted by the market research company YouGov in March 2022, we present prevalence estimates of e-cigarette and tobacco use. We use logistic regression models to assess differences in e-cigarette use, tobacco use and use of disposable e-cigarettes across a range of covariates including age, sex, tobacco smoking status, social class, and country. Results: Among the 18.0% of those surveyed who reported ever having smoked a cigarette, 83.9% were not regular (at least once per week) smokers and 16.1% were (15.1% and 2.9% of the total sample, respectively). Among the 19.2% of those surveyed who had ever used an e-cigarette, 79.2% were not regular users, while 20.8% were (15.2% and 4.0% of the total sample, respectively). Regular e-cigarette use was more common than regular tobacco smoking (4.0% vs 2.9%). E-cigarette use was more common among those who also smoked tobacco, with 9.0% of never e-cigarette users ever smoking tobacco, compared with 89.4% of regular e-cigarette users. Both smoking and e-cigarette use were associated with increasing age and use by others within the home, but not with social class. Use of disposable e-cigarettes was reported by 53.8% of those who have ever used an e-cigarette, and more common among females than males. Conclusions: Regular e-cigarette use is now more common than smoking in children and youth, though the majority of this is among those who have also smoked tobacco. Measures to reduce the appeal of both e-cigarettes and tobacco to children and young people are warranted
Size and Shape Differences Between Male and Female Foot Bones
This study introduces a new technique to measure bone size and
shape. A three-dimensional laser scan was taken of the talus, navicular,
medial cuneiform, and first metatarsal from 107 skeletons of known age
and sex. The bones were analyzed for differences in bone morphology
between the sexes and the ability of each bone to contribute to the adducted
position of the first metatarsal. Linear measurements showed
that male bones were larger than female bones. Measurements of articular
surfaces suggested that female bones had the potential for more
movement to occur in the direction of adduction, possibly resulting in
the female first metatarsal being more adducted than that in the male
skeleton. Such differences may underlie the predisposition of the female
foot to develop hallux valgus deformity
REBUILD: Regenerative Buildings and construction systems for a circular economy
This is the final version. Available from IOP via the DOI in this record. Buildings and construction have been identified as having one of the greatest potential for value creation and capture from the application of circular economy principles. To achieve this requires a fundamental transformation in the recovery, remanufacture and re-use of end of service life structural products such as steel, bricks, concrete which make up the largest proportion of materials. At the same time these products must be re-used in new buildings and infrastructure designed for subsequent deconstruction and disassembly. REBUILD is a 3 year way UK research project to address this challenge. Initial findings on quantifying the material intensity of buildings (stock and flow assessment) are presented based on one of our case study cities. Results from new techniques to separate and reclaim bricks from cement mortar shows technical feasibility and ability to retain structural performance. Details on the next stage of scaling this work and techniques for separating and reclaiming steel and concrete are briefly described. Subsequent stage of life cycle assessment, value stream mapping and creating products for new forms of circular building and construction systems are also described. The paper concludes that whilst there are considerable challenges in reclaiming structural products that re-designed circular building and construction system could transform the value of end of service life buildings and the offers new opportunities for circular innovation and the circulation of materials and products at their highest value for the longest period.Engineering and Physical Science Research Council (EPSRC)European Union’s Horizon 2020 research and innovation programm
Moving singing for lung health online in response to COVID-19: experience from a randomised controlled trial
Introduction Singing for Lung Health (SLH) is a popular arts-in-health activity for people with long-term respiratory conditions. Participants report biopsychosocial benefits, however research on impact is limited. The ‘SHIELD trial’, a randomised controlled, single (assessor) blind, trial of 12 weeks SLH vs usual care for people with Chronic Obstructive Pulmonary Disease (COPD) (n=120) was set-up to help to address this. The first group (n=18, 9 singing and 9 controls) started face-to-face (5 sessions) before changing to online delivery (7 sessions) due to COVID-19 related physical distancing measures. As such, the experience of this group is here reported as a pilot study to inform further research in this area. Methods We conducted semi-structured interviews and thematic analysis regarding barriers, facilitators and key considerations for transitioning from face-to-face to online delivery. Pilot quantitative outcomes include attendance, pre and post measures of quality of life and disease impact (SF-36, CAT score), breathlessness (MRC breathlessness scale, Dyspnoea-12), depression (PHQ9), anxiety (GAD-7), balance confidence (ABC scale) and physical activity (clinical visit PROactive physical activity in COPD tool, combining subjective rating and actigraphy). Results Attendance was 69% overall, (90% of the face-to-face sessions, 53% online sessions). Analysis of semi-structured interviews identified three themes regarding participation in SLH delivered face-to-face and online, these where 1) perceived benefits; 2) digital barriers (online); 3) digital facilitators (online). Findings were summarised into key considerations for optimising transitioning singing groups from face-to-face to online delivery. Pilot quantitative data suggested possible improvements in depression (treatment effect -4.78 PHQ9 points, p< 0.05, MCID 5) and balance confidence (treatment effect +17.21 ABC Scale points, p=0.04, MCID 14.2). Discussion This study identifies key considerations regarding the adaptation of SLH from face-to-face to online delivery. Pilot data suggest online group singing for people with COPD may deliver benefits related to reducing depression and improved balance confidence
- …