5,417 research outputs found
Daily and Seasonal Variation in the Spectral Composition of Light Exposure in Humans
Light is considered the most potent synchronizer of the human circadian system and exerts many other non-image-forming effects, including those that affect brain function. These effects are mediated in part by intrinsically photosensitive retinal ganglion cells that express the photopigment melanopsin. The spectral sensitivity of melanopsin is greatest for blue light at approximately 480 nm. At present, there is little information on how the spectral composition of light to which people are exposed varies over the 24 h period and across seasons. Twenty-two subjects, aged 22±4 yrs (mean±SD) participated during the winter months (November–February), and 12 subjects aged 25±3 yrs participated during the summer months (April–August). Subjects wore Actiwatch-RGB monitors, as well as Actiwatch-L monitors, for seven consecutive days while living in England. These monitors measured activity and light exposure in the red, green, and blue spectral regions, in addition to broad-spectrum white light, with a 2 min resolution. Light exposure during the day was analyzed for the interval between 09:00 and 21:00 h. The time course of white-light exposure differed significantly between seasons (p = 0.0022), with light exposure increasing in the morning hours and declining in the afternoon hours, and with a more prominent decline in the winter. Overall light exposure was significantly higher in summer than winter (p = 0.0002). Seasonal differences in the relative contribution of blue-light exposure to overall light exposure were also observed (p = 0.0006), in particular during the evening hours. During the summer evenings (17:00–21:00 h), the relative contribution of blue light was significantly higher (p < 0.0001) (40.2±1.1%) than during winter evenings (26.6±0.9%). The present data show that in addition to overall light exposure, the spectral composition of light exposure varies over the day and with season
Investigating the relationship between substance use and sexual behaviour in young people in Britain: findings from a national probability survey.
BACKGROUND: Health risk behaviours are prominent in late adolescence and young adulthood, yet UK population-level research examining the relationship between drug or alcohol use and sexual health and behaviour among young people is scarce, despite public health calls for an integrated approach to health improvement. Our objective was to further our understanding of the scale of and nature of any such relationship, using contemporary data from Britain's third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). METHODS: Analyses of data from Natsal-3, a stratified probability survey of 15 162 men and women (3869 aged 16-24 years), undertaken in 2010-2012, using computer-assisted personal interviewing, were carried out. Logistic regression was used to explore associations between reporting (1) frequent binge drinking (≥weekly), (2) recent drug use (within past 4 weeks) or (3) multiple (both types of) substance use, and key sexual risk behaviours and adverse sexual health outcomes. We then examined the sociodemographic profile, health behaviours and attitudes reported by 'risky' young people, defined as those reporting ≥1 type of substance use plus non-condom use at first sex with ≥1 new partner(s), last year. RESULTS: Men and women reporting frequent binge drinking or recent drug use were more likely to report: unprotected first sex with ≥1 new partner(s), last year; first sex with their last partner after only recently meeting; emergency contraception use (last year) and sexually transmitted infection diagnosis/es (past 5 years). Associations with sexual risk were frequently stronger for those reporting multiple substance use, particularly among men. The profile of 'risky' young people differed from that of other 16-24 years old. CONCLUSIONS: In this nationally representative study, substance use was strongly associated with sexual risk and adverse sexual health outcomes among young people. Qualitative or event-level research is needed to examine the context and motivations behind these associations to inform joined-up interventions to address these inter-related behaviours
Symmetric informationally complete positive operator valued measure and probability representation of quantum mechanics
Symmetric informationally complete positive operator valued measures
(SIC-POVMs) are studied within the framework of the probability representation
of quantum mechanics. A SIC-POVM is shown to be a special case of the
probability representation. The problem of SIC-POVM existence is formulated in
terms of symbols of operators associated with a star-product quantization
scheme. We show that SIC-POVMs (if they do exist) must obey general rules of
the star product, and, starting from this fact, we derive new relations on
SIC-projectors. The case of qubits is considered in detail, in particular, the
relation between the SIC probability representation and other probability
representations is established, the connection with mutually unbiased bases is
discussed, and comments to the Lie algebraic structure of SIC-POVMs are
presented.Comment: 22 pages, 1 figure, LaTeX, partially presented at the Workshop
"Nonlinearity and Coherence in Classical and Quantum Systems" held at the
University "Federico II" in Naples, Italy on December 4, 2009 in honor of
Prof. Margarita A. Man'ko in connection with her 70th birthday, minor
misprints are corrected in the second versio
InGaAs spin light emitting diodes measured in the Faraday and oblique Hanle geometries
InGaAs quantum well light emitting diodes (LED) with spin-injecting, epitaxial Fe contacts were fabricated using an in situ wafer transfer process where the semiconductor wafer was transferred under ultrahigh vacuum (UHV) conditions to a metals growth chamber to achieve a high quality interface between the two materials. The spin LED devices were measured optically with applied magnetic fields in either the Faraday or the oblique Hanle geometries in two experimental set-ups. Optical polarizations efficiencies of 4.5% in the Faraday geometry and 1.5% in the Hanle geometry are shown to be equivalent. The polarization efficiency of the electroluminescence is seen to decay as the temperature increases although the spin lifetime remains constant due to the influence of the D'yakonov–Perel' spin scattering mechanism in the quantum well.RM would like to acknowledge support from the EPSRC.This is the final version of the article. It first appeared from the Institute of Physics via https://doi.org/10.1088/0022-3727/49/16/16510
Referrals for proliferative diabetic retinopathy from two UK diabetic retinopathy screening services: a 10-year analysis of visual outcomes, requirement for vitrectomy, and mortality
\ua9 The Author(s) 2024. Background/objectives: To determine long-term outcomes of patients referred with proliferative diabetic retinopathy (PDR) from diabetic eye screening programmes (DESP) to tertiary care centres in the United Kingdom (UK). Methods: Retrospective multicentre study of patients referred from two DESPs in the UK over a 36-month period (2007–9) and followed-up for 10 years. Critical outcomes included severe vision loss (SVL) and the need for vitrectomy. Other outcomes assessed included moderate vision loss (MVL), and patient survival time. Univariate and multiple variable Cox proportional hazards regressions were used to analyse survival outcomes. Results: 212 eyes of 150 patients were referred with a diagnosis of PDR. 109 eyes of 72 patients were confirmed to have active PDR and included in the study. 61% of patients had low-risk PDR, while 39% exhibited high-risk features in at least one eye. Eight (7.3%) eyes developed SVL and 16 (14.7%) MVL during follow up. Vitrectomy was required in 24% (95% CI: 15 to 31%) of all PDR eyes and was most commonly performed for vitreous haemorrhage (65%). The 10-year survival in all PDR patients was 76% (95% CI: 63 to 85%) with the mean time to death for all deceased patients being 5.4 \ub1 3.6 years. On multivariable analysis, only age was found to have a significant association with the survival of patients with PDR. Conclusions: During the 10 year follow up SVL was uncommon, but MVL occurred in almost one-fifth of the eyes. Approximately 1 in 4 eyes required vitrectomy, highlighting its significance in patient management
Ruptured pseudocyst of pancreas presenting with paraplegia: a case report
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
The availability of water associated with glycogen during dehydration; a reservoir or raindrop?
Interoceptive training to target anxiety in autistic adults (ADIE): A single-center, superiority randomized controlled trial
Background: This trial tested if a novel therapy, Aligning Dimensions of Interoceptive Experience (ADIE), reduces anxiety in autistic adults. ADIE targets the association of anxiety with mismatch between subjective and behavioral measures of an individual's interoceptive sensitivity to bodily signals, including heartbeats. // Methods: In this superiority randomized controlled trial, autistic adults (18–65 years) from clinical and community settings in Southern England were randomly assigned (1:1) to receive six sessions of ADIE or an active ‘exteroceptive’ control therapy (emotional prosody identification). Researchers conducting outcome assessments were blind to allocation. ADIE combines two modified heartbeat detection tasks with performance feedback and physical activity manipulation that transiently increases cardiac arousal. Participants were followed-up one-week (T1) and 3-months post-intervention (T2). The primary outcome was Spielberger Trait Anxiety Score (STAI-T) at T2. Outcomes were assessed on an intention-to-treat basis using multiple imputation for dealing with missing values. This trial was registered at International Standard Randomized Controlled Trial Registry, ISRCTN14848787. // Findings: Between July 01, 2017, and December 31, 2019, 121 participants were randomly allocated to ADIE (n = 61) or prosody (n = 60) intervention groups. Data at T1 was provided by 85 (70%) participants (46 [75%] ADIE; 39 [65%] prosody). Data at T2 was provided by 61 (50%) participants (36 [59%] ADIE; 25 [42%] prosody). One adverse event (cardiac anxiety following ADIE) was recorded. A statistically significant group effect of ADIE on trait anxiety continued at T2 (estimated mean difference 3•23 [95% CI 1•13 to 5•29]; d = 0•30 [95% CI 0•09 to 0•51]; p = 0•005) with 31% of ADIE group participants meeting trial criteria for recovery (compared to 16% in the control group). // Interpretation: ADIE can reduce anxiety in autistic adults, putatively improving regulatory control over internal stimuli. With little reliance on language and emotional insight, ADIE may constitute an inclusive intervention
Simulating Reionization: Character and Observability
In recent years there has been considerable progress in our understanding of
the nature and properties of the reionization process. In particular, the
numerical simulations of this epoch have made a qualitative leap forward,
reaching sufficiently large scales to derive the characteristic scales of the
reionization process and thus allowing for realistic observational predictions.
Our group has recently performed the first such large-scale radiative transfer
simulations of reionization, run on top of state-of-the-art simulations of
early structure formation. This allowed us to make the first realistic
observational predictions about the Epoch of Reionization based on detailed
radiative transfer and structure formation simulations. We discuss the basic
features of reionization derived from our simulations and some recent results
on the observational implications for the high-redshift Ly-alpha sources.Comment: 3 pages, to appear in the Proceedings of First Stars III, Santa Fe,
July 2007, AIP Conference Serie
Using the DPSIR framework for transdisciplinary training and knowledge elicitation in the Gulf of Thailand
No abstract available
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