1,028 research outputs found
Spacecraft instrument calibration and stability
The following topics are covered: instrument degradation; the Solar Backscatter Ultraviolet (SBUV) Experiment; the Total Ozone Mapping Spectrometer (TOMS); the Stratospheric Aerosol and Gas Experiment 1 (SAGE-1) and SAGE-2 instruments; the Solar Mesosphere Explorer (SME) UV ozone and near infrared airglow instruments; and the Limb Infrared Monitor of the Stratosphere (LIMS)
Quantum statistical effects in nano-oscillator arrays
We have theoretically predicted the density of states(DOS), the low
temperature specific heat, and Brillouin scattering spectra of a large, free
standing array of coupled nano-oscillators. We have found significant gaps in
the DOS of 2D elastic systems, and predict the average DOS to be nearly
independent of frequency over a broad band f < 50GHz. At low temperatures, the
measurements probe the quantum statistics obeyed by rigid body modes of the
array and, thus, could be used to verify the quantization of the associated
energy levels. These states, in turn, involve center-of mass motion of large
numbers of atoms, N > 1.e14, and therefore such observations would extend the
domain in which quantum mechanics has been experimentally tested. We have found
the required measurement capability to carry out this investigation to be
within reach of current technology.Comment: 1 tex file, 3 figures, 1 bbl fil
Changes in body weight and food choice in those attempting smoking cessation: a cluster randomised controlled trial
<p><b>Background:</b> Fear of weight gain is a barrier to smoking cessation and significant cause of relapse for many people. The provision of nutritional advice as part of a smoking cessation programme may assist some in smoking cessation and perhaps limit weight gain. The aim of this study was to determine the effect of a structured programme of dietary advice on weight change and food choice, in adults attempting smoking cessation.</p>
<p><b>Methods:</b> Cluster randomised controlled design. Classes randomised to intervention commenced a 24-week intervention, focussed on improving food choice and minimising weight gain. Classes randomised to control received "usual care".</p>
<p><b>Results:</b> Twenty-seven classes in Greater Glasgow were randomised between January and August 2008. Analysis, including those who continued to smoke, showed that actual weight gain and percentage weight gain was similar in both groups. Examination of data for those successful at giving up smoking showed greater mean weight gain in intervention subjects (3.9 (SD 3.1) vs. 2.7 (SD 3.7) kg). Between group differences were not significant (p=0.23, 95% CI -0.9 to 3.5). In comparison to baseline improved consumption of fruit and vegetables and breakfast cereal were reported in the intervention group. A higher percentage of control participants continued smoking (74% vs. 66%).</p>
<p><b>Conclusions:</b> The intervention was not successful at minimising weight gain in comparison to control but was successful in facilitating some sustained improvements in the dietary habits of intervention participants. Improved quit rates in the intervention group suggest that continued contact with advisors may have reduced anxieties regarding weight gain and encouraged cessation despite weight gain. Research should continue in this area as evidence suggests that the negative effects of obesity could outweigh the health benefits achieved through reductions in smoking prevalence.</p>
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Ensemble prediction for nowcasting with a convection-permitting model - II: forecast error statistics
A 24-member ensemble of 1-h high-resolution forecasts over the Southern United Kingdom is used to study short-range forecast error statistics. The initial conditions are found from perturbations from an ensemble transform Kalman filter. Forecasts from this system are assumed to lie within the bounds of forecast error of an operational forecast system. Although noisy, this system is capable of producing physically reasonable statistics which are analysed and compared to statistics implied from a variational assimilation system. The variances for temperature errors for instance show structures that reflect convective activity. Some variables, notably potential temperature and specific humidity perturbations, have autocorrelation functions that deviate from 3-D isotropy at the convective-scale (horizontal scales less than 10 km). Other variables, notably the velocity potential for horizontal divergence perturbations, maintain 3-D isotropy at all scales. Geostrophic and hydrostatic balances are studied by examining correlations between terms in the divergence and vertical momentum equations respectively. Both balances are found to decay as the horizontal scale decreases. It is estimated that geostrophic balance becomes less important at scales smaller than 75 km, and hydrostatic balance becomes less important at scales smaller than 35 km, although more work is required to validate these findings. The implications of these results for high-resolution data assimilation are discussed
Clinical outcomes and costs for people with complex psychosis; a naturalistic prospective cohort study of mental health rehabilitation service users in England.
BACKGROUND: Mental health rehabilitation services in England focus on people with complex psychosis. This group tend to have lengthy hospital admissions due to the severity of their problems and, despite representing only 10-20 % of all those with psychosis, they absorb 25-50 % of the total mental health budget. Few studies have investigated the effectiveness of these services and there is little evidence available to guide clinicians working in this area. As part of a programme of research into inpatient mental health rehabilitation services, we carried out a prospective study to investigate longitudinal outcomes and costs for patients of these services and the predictors of better outcome. METHOD: Inpatient mental health rehabilitation services across England that scored above average (median) on a standardised quality assessment tool used in a previous national survey were eligible for the study. Unit quality was reassessed and costs of care and patient characteristics rated using standardised tools at recruitment. Multivariable regression modelling was used to investigate the relationship between service quality, patient characteristics and the following clinical outcomes at 12 month follow-up: social function; length of admission in the rehabiliation unit; successful community discharge (without readmission or community placement breakdown) and costs of care. RESULTS: Across England, 50 units participated and 329 patients were followed over 12 months (94 % of those recruited). Service quality was not associated with patients' social function or length of admission (median 16 months) at 12 months but most patients were successfully discharged (56 %) or ready for discharge (14 %), with associated reductions in the costs of care. Factors associated with successful discharge were the recovery orientation of the service (OR 1.04, 95 % CI 1.00-1.08), and patients' activity (OR 1.03, 95 % CI 1.01-1.05) and social skills (OR 1.13, 95 % CI 1.04-1.24) at recruitment. CONCLUSION: Inpatient mental health rehabilitation services in England are able to successfully discharge over half their patients within 18 months, reducing the costs of care for this complex group. Provision of recovery orientated practice that promotes patients' social skills and activities may further enhance the effectiveness of these services
Buoyancy-induced time delays in Babcock-Leighton flux-transport dynamo models
The Sun is a magnetic star whose cyclic activity is thought to be linked to
internal dynamo mechanisms. A combination of numerical modelling with various
levels of complexity is an efficient and accurate tool to investigate such
intricate dynamical processes. We investigate the role of the magnetic buoyancy
process in 2D Babcock-Leighton dynamo models, by modelling more accurately the
surface source term for poloidal field. Methods. To do so, we reintroduce in
mean-field models the results of full 3D MHD calculations of the non-linear
evolution of a rising flux tube in a convective shell. More specifically, the
Babcock-Leighton source term is modified to take into account the delay
introduced by the rise time of the toroidal structures from the base of the
convection zone to the solar surface. We find that the time delays introduced
in the equations produce large temporal modulation of the cycle amplitude even
when strong and thus rapidly rising flux tubes are considered. Aperiodic
modulations of the solar cycle appear after a sequence of period doubling
bifurcations typical of non-linear systems. The strong effects introduced even
by small delays is found to be due to the dependence of the delays on the
magnetic field strength at the base of the convection zone, the modulation
being much less when time delays remain constant. We do not find any
significant influence on the cycle period except when the delays are made
artificially strong. A possible new origin of the solar cycle variability is
here revealed. This modulated activity and the resulting butterfly diagram are
then more compatible with observations than what the standard Babcock-Leighton
model produces.Comment: 13 pages, 10 figures, accepted for publication in A&
Prenatal exposure to maternal social disadvantage and psychosocial stress and neonatal white matter connectivity at birth
Early life adversity (social disadvantage and psychosocial stressors) is associated with altered microstructure in fronto-limbic pathways important for socioemotional development. Understanding when these associations begin to emerge may inform the timing and design of preventative interventions. In this longitudinal study, 399 mothers were oversampled for low income and completed social background measures during pregnancy. Measures were analyzed with structural equation analysis resulting in two latent factors: social disadvantage (education, insurance status, income-to-needs ratio [INR], neighborhood deprivation, and nutrition) and psychosocial stress (depression, stress, life events, and racial discrimination). At birth, 289 healthy term-born neonates underwent a diffusion MRI (dMRI) scan. Mean diffusivity (MD) and fractional anisotropy (FA) were measured for the dorsal and inferior cingulum bundle (CB), uncinate, and fornix using probabilistic tractography in FSL. Social disadvantage and psychosocial stress were fitted to dMRI parameters using regression models adjusted for infant postmenstrual age at scan and sex. Social disadvantage, but not psychosocial stress, was independently associated with lower MD in the bilateral inferior CB and left uncinate, right fornix, and lower MD and higher FA in the right dorsal CB. Results persisted after accounting for maternal medical morbidities and prenatal drug exposure. In moderation analysis, psychosocial stress was associated with lower MD in the left inferior CB among the lower-to-higher socioeconomic status (SES) (INR ≥ 200%) group, but not the extremely low SES (INR \u3c 200%) group. Increasing access to social welfare programs that reduce the burden of social disadvantage and related psychosocial stressors may be an important target to protect fetal brain development in fronto-limbic pathways
Imagining the future at the global and national scale: a comparative study of British and Dutch press coverage of Rio 1992 and Rio 2012
Climate change and imagined futures are intricately linked, discussed by policymakers and reported in the media. In this article we focus on the construction of future expectation in the press coverage of the 1992 and 2012 United Nations conferences in Rio de Janeiro in British and Dutch national newspapers. We use a novel combination of methods, semantic co-word networks and metaphor analysis to analyse imagined futures. Our findings show that between 1992 and 2012 there was a switch from future-oriented hope to past-oriented disappointment regarding implementing international agreements on climate change policy. While the UK focused on global issues, the Netherlands focused on national (including colonial) and local ones, reflecting different views and expectations about the future of climate change adaptation and mitigation
The relationship between construction sector and the national economy of Sri Lanka
The causal relationship between construction and a country’s economy has received much attention in the past. However, the results provide contrasting views on the nature of this relationship. This paper therefore investigates the direction of the causal relationship between construction and the economy of a developing country, Sri Lanka. It uses empirical data for selected economic and construction indicators for the period 1990–2009. The pattern of the causal relationship was determined using Granger causality test. The findings reveal that for all indicators except construction investment, national economic activities precede that of construction. The study therefore concludes and strengthens the body of knowledge on Sri Lanka that the causal relationship between its construction sector and national economy tend towards a uni-directional relationship with the national economy inducing growth in the construction sector and not vice versa
Neonatal motor functional connectivity and motor outcomes at age two years in very preterm children with and without high-grade brain injury
Preterm-born children have high rates of motor impairments, but mechanisms for early identification remain limited. We hypothesized that neonatal motor system functional connectivity (FC) would relate to motor outcomes at age two years; currently, this relationship is not yet well-described in very preterm (VPT; born \u3c32 weeks\u27 gestation) infants with and without brain injury. We recruited 107 VPT infants - including 55 with brain injury (grade III-IV intraventricular hemorrhage, cystic periventricular leukomalacia, post-hemorrhagic hydrocephalus) - and collected FC data at/near term-equivalent age (35-45 weeks postmenstrual age). Correlation coefficients were used to calculate the FC between bilateral motor and visual cortices and thalami. At two years corrected-age, motor outcomes were assessed with the Bayley Scales of Infant and Toddler Development, 3rd edition. Multiple imputation was used to estimate missing data, and regression models related FC measures to motor outcomes. Within the brain-injured group only, interhemispheric motor cortex FC was positively related to gross motor outcomes. Thalamocortical and visual FC were not related to motor scores. This suggests neonatal alterations in motor system FC may provide prognostic information about impairments in children with brain injury
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