14,478 research outputs found
Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 6: Closed-cycle gas turbine systems
Both recuperated and bottomed closed cycle gas turbine systems in electric power plants were studied. All systems used a pressurizing gas turbine coupled with a pressurized furnace to heat the helium for the closed cycle gas turbine. Steam and organic vapors are used as Rankine bottoming fluids. Although plant efficiencies of over 40% are calculated for some plants, the resultant cost of electricity was found to be 8.75 mills/MJ (31.5 mills/kWh). These plants do not appear practical for coal or oil fired plants
Eta Carinae across the 2003.5 Minimum: Analysis in the visible and near infrared spectral region
We present an analysis of the visible through near infrared spectrum of Eta
Carinae and its ejecta obtained during the "Eta Carinae Campaign with the UVES
at the ESO VLT". This is a part of larger effort to present a complete Eta
Carinae spectrum, and extends the previously presented analyses with the
HST/STIS in the UV (1240-3159 A) to 10,430 A. The spectrum in the mid and near
UV is characterized by the ejecta absorption. At longer wavelengths, stellar
wind features from the central source and narrow emission lines from the
Weigelt condensations dominate the spectrum. However, narrow absorption lines
from the circumstellar shells are present. This paper provides a description of
the spectrum between 3060 and 10,430 A, including line identifications of the
ejecta absorption spectrum, the emission spectrum from the Weigelt
condensations and the P-Cygni stellar wind features. The high spectral
resolving power of VLT/UVES enables equivalent width measurements of atomic and
molecular absorption lines for elements with no transitions at the shorter
wavelengths. However, the ground based seeing and contributions of nebular
scattered radiation prevent direct comparison of measured equivalent widths in
the VLT/UVES and HST/STIS spectra. Fortunately, HST/STIS and VLT/UVES have a
small overlap in wavelength coverage which allows us to compare and adjust for
the difference in scattered radiation entering the instruments' apertures. This
paper provides a complete online VLT/UVES spectrum with line identifications
and a spectral comparison between HST/STIS and VLT/UVES between 3060 and 3160
A.Comment: 13 pages, 11 figures + atlas. The paper accepted for the ApJS and is
accompanied with an atlas in the online edition pape
Similarity Measure Development for Case-Based Reasoning- A Data-driven Approach
In this paper, we demonstrate a data-driven methodology for modelling the
local similarity measures of various attributes in a dataset. We analyse the
spread in the numerical attributes and estimate their distribution using
polynomial function to showcase an approach for deriving strong initial value
ranges of numerical attributes and use a non-overlapping distribution for
categorical attributes such that the entire similarity range [0,1] is utilized.
We use an open source dataset for demonstrating modelling and development of
the similarity measures and will present a case-based reasoning (CBR) system
that can be used to search for the most relevant similar cases
The set-shifting profiles of anorexia nervosa and autism spectrum disorder using the Wisconsin Card Sorting Test: a systematic review and meta-analysis
Difficulties in set-shifting are commonly reported in both autism spectrum disorder (ASD) and anorexia nervosa (AN) populations. Despite this, it is not known whether this cognitive profile persists across different ages, or whether the profiles seen in ASD and AN are comparable. This systematic review and meta-analyses aimed to compare the set-shifting profiles, as measured by the Wisconsin Card Sorting Test (WCST) in adults and younger people with either ASD or AN, relative to healthy controls (HCs) and to statistically compare performance on the WCST between ASD and AN. In all, 24 studies on ASD and 22 studies on AN were identified. In ASD, there were significant differences between the clinical group and HCs, with the ASD group making significantly more perseverative errors, indicating greater difficulty in set-shifting [pooled effect size of d = 0.67, 95% confidence interval (CI) 0.53-0.81, p ⩽ 0.001]. This effect was consistent across the age span. For AN studies, there was a significant difference between adults with AN and HCs (d = 0.52, 95% CI 0.36-0.68, p ⩽ 0.001) but a non-significant effect in child studies (d = 0.25, 95% CI -0.05 to 0.55, z = 1.66, p = 0.096). Meta-regression indicated no effect of diagnosis (AN or ASD) on performance in adult studies but there was a non-significant trend (p = 0.053) towards children with ASD performing worse than children with AN. While difficulties with set-shifting appear to be stable in ASD, there may be differences between children and adults with AN, which warrant further investigation
Enhanced motivational interviewing for reducing weight and increasing physical activity in adults with high cardiovascular risk: the MOVE IT three-arm RCT.
BACKGROUND: Motivational interviewing (MI) enhanced with behaviour change techniques (BCTs) and deployed by health trainers targeting multiple risk factors for cardiovascular disease (CVD) may be more effective than interventions targeting a single risk factor. OBJECTIVES: The clinical effectiveness and cost-effectiveness of an enhanced lifestyle motivational interviewing intervention for patients at high risk of CVD in group settings versus individual settings and usual care (UC) in reducing weight and increasing physical activity (PA) were tested. DESIGN: This was a three-arm, single-blind, parallel randomised controlled trial. SETTING: A total of 135 general practices across all 12 South London Clinical Commissioning Groups were recruited. PARTICIPANTS: A total of 1742 participants aged 40-74 years with a ≥ 20.0% risk of a CVD event in the following 10 years were randomised. INTERVENTIONS: The intervention was designed to integrate MI and cognitive-behavioural therapy (CBT), delivered by trained healthy lifestyle facilitators in 10 sessions over 1 year, in group or individual format. The control group received UC. RANDOMISATION: Simple randomisation was used with computer-generated randomisation blocks. In each block, 10 participants were randomised to the group, individual or UC arm in a 4 : 3 : 3 ratio. Researchers were blind to the allocation. MAIN OUTCOME MEASURES: The primary outcomes are change in weight (kg) from baseline and change in PA (average number of steps per day over 1 week) from baseline at the 24-month follow-up, with an interim follow-up at 12 months. An economic evaluation estimates the relative cost-effectiveness of each intervention. Secondary outcomes include changes in low-density lipoprotein cholesterol and CVD risk score. RESULTS: The mean age of participants was 69.75 years (standard deviation 4.11 years), 85.5% were male and 89.4% were white. At the 24-month follow-up, the group and individual intervention arms were not more effective than UC in increasing PA [mean 70.05 steps, 95% confidence interval (CI) -288 to 147.9 steps, and mean 7.24 steps, 95% CI -224.01 to 238.5 steps, respectively] or in reducing weight (mean -0.03 kg, 95% CI -0.49 to 0.44 kg, and mean -0.42 kg, 95% CI -0.93 to 0.09 kg, respectively). At the 12-month follow-up, the group and individual intervention arms were not more effective than UC in increasing PA (mean 131.1 steps, 95% CI -85.28 to 347.48 steps, and mean 210.22 steps, 95% CI -19.46 to 439.91 steps, respectively), but there were reductions in weight for the group and individual intervention arms compared with UC (mean -0.52 kg, 95% CI -0.90 to -0.13 kg, and mean -0.55 kg, 95% CI -0.95 to -0.14 kg, respectively). The group intervention arm was not more effective than the individual intervention arm in improving outcomes at either follow-up point. The group and individual interventions were not cost-effective. CONCLUSIONS: Enhanced MI, in group or individual formats, targeted at members of the general population with high CVD risk is not effective in reducing weight or increasing PA compared with UC. Future work should focus on ensuring objective evidence of high competency in BCTs, identifying those with modifiable factors for CVD risk and improving engagement of patients and primary care. TRIAL REGISTRATION: Current Controlled Trials ISRCTN84864870. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 69. See the NIHR Journals Library website for further project information. This research was part-funded by the NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London
Dust Formation and He II 4686 emission in the Dense Shell of the Peculiar Type Ib Supernova 2006jc
We present evidence for the formation of dust grains in an unusual Type Ib SN
based on late-time spectra of SN 2006jc. The progenitor suffered an LBV-like
outburst just 2 yr earlier, and we propose that the dust formation is a
consequence of the SN blast wave overtaking that LBV-like shell. The key
evidence for dust formation is (a) the appearance of a red/near-IR continuum
source fit by 1600 K graphite grains, and (b) fading of the redshifted sides of
He I emission lines, yielding progressively more asymmetric blueshifted lines
as dust obscures receding material. This provides the strongest case yet for
dust formation in any SN Ib/c. Both developments occurred between 51 and 75 d
after peak, while other SNe observed to form dust did so after a few hundred
days. Geometric considerations indicate that dust formed in the dense swept-up
shell between the forward and reverse shocks, and not in the freely expanding
SN ejecta. Rapid cooling leading to dust formation may have been aided by
extremely high shell densities, as indicated by He I line ratios. The brief
epoch of dust formation is accompanied by He II 4686 emission and enhanced
X-ray emission. These clues suggest that the unusual dust formation in this
object was not due to properties of the SN itself, but instead -- like most
peculiarities of SN 2006jc -- was a consequence of the dense environment
created by an LBV-like eruption 2 yr before the SN.Comment: ApJ, accepted. added some discussion and 2 figures, better title,
conclusions same as previous version. 12 pages, 4 color fig
Recommended from our members
Reducing weight and increasing physical activity in people at high risk of cardiovascular disease: a randomised controlled trial comparing the effectiveness of enhanced motivational interviewing intervention with usual care.
OBJECTIVE: The epidemic of obesity is contributing to the increasing prevalence of people at high risk of cardiovascular disease (CVD), negating the medical advances in reducing CVD mortality. We compared the clinical and cost-effectiveness of an intensive lifestyle intervention consisting of enhanced motivational interviewing in reducing weight and increasing physical activity for patients at high risk of CVD. METHODS: A three-arm, single-blind, parallel-group randomised controlled trial was conducted in consenting primary care centres in south London. We recruited patients aged 40-74 years with a QRisk2 score ≥20.0%, which indicates the probability of having a CVD event in the next 10 years. The intervention was enhanced motivational interviewing which included additional behaviour change techniques and was delivered by health trainers in 10 sessions over 1 year, in either group (n=697) or individual (n=523) format. The third arm received usual care (UC; n=522). The primary outcomes were physical activity (mean steps/day) and weight (kg). Secondary outcomes were changes in low-density lipoprotein cholesterol and CVD risk score. We estimated the relative cost-effectiveness of each intervention. RESULTS: At 24 months, the group and individual interventions were not more effective than UC in increasing physical activity (mean difference=70.05 steps, 95% CI -288.00 to 147.90 and mean difference=7.24 steps, 95% CI -224.01 to 238.50, respectively), reducing weight (mean difference=-0.03 kg, 95% CI -0.49 to 0.44 and mean difference=-0.42 kg, 95% CI -0.93 to 0.09, respectively) or improving any secondary outcomes. The group and individual interventions were not cost-effective at conventional thresholds. CONCLUSIONS: Enhancing motivational interviewing with additional behaviour change techniques was not effective in reducing weight or increasing physical activity in those at high CVD risk
Psychological interventions to improve glycemic control in adults with type 2 diabetes: a systematic review and meta-analysis
The quality of evidence that psychological interventions are effective in improving glycemic control in adults with type 2 diabetes (T2D) is weak.
We conducted a systematic review and meta-analysis of psychological interventions in T2D to assess whether their effectiveness in improving glycemic levels has improved over the past 30 years. We applied the protocol of a systematic review and aggregate meta-analysis conducted to January 2003. We added network meta-analysis (NMA) to compare intervention and control group type against usual care. MEDLINE, Cumulative Index to Nursing and Allied Health Literature, PsycINFO, EMBASE, Cochrane Controlled Trials Database, Web of Science, and Dissertation Abstracts International were searched from January 2003 to July 2018. Only randomized controlled trials (RCT) of psychological interventions for adults with T2D reported in any language were included. The primary outcome was change in glycemic control (glycated hemoglobin (HbA1c) in mmol/mol). Data were extracted from study reports and authors were contacted for missing data.
94 RCTs were eligible for inclusion in the systematic review since the last review. In 70 RCTs (n=14 796 participants) the pooled mean difference in HbA1c in those randomized to psychological intervention compared with control group was −0.19 (95% CI −0.25 to −0.12), equivalent to a reduction in HbA1c of 3.7 mmol/mol, with moderate heterogeneity across studies (I2=64.7%, p<0.001). NMA suggested the probability of intervention effectiveness is highest for self-help materials, cognitive–behavioral therapy, and counseling, compared with usual care. Limitations of this study include that there is a possibility that some studies may have been missed if diabetes did not appear in the title or abstract.
The effectiveness of psychological interventions for adults with T2D have minimal clinical benefit in improving glycemic control.
PROSPERO registration number CRD42016033619
Systematic review and meta‐analysis of randomized controlled trials of psychological interventions to improve glycaemic control in children and adults with type 1 diabetes
Aim
We conducted a systematic review aggregate and network meta‐analysis of psychological interventions for people with type 1 diabetes to assess their effectiveness in improving glycaemic levels.
Methods
We searched the following databases from 1 January 2003 to 1 July 2018: MEDLINE, CINAHL, PsycINFO, Embase, Cochrane Controlled Trials, Web of Science, clinicaltrials.gov, Dissertation Abstract International. We included randomized controlled trials (RCT) of psychological interventions for children and adults with type 1 diabetes reported in any language. We extracted data on publications, participant characteristics at baseline, intervention and control group, and data for the primary outcome, change in glycaemic control [HbA1c (mmol/mol/%)]. Study authors were contacted for missing data. The review was registered with international prospective register of systematic reviews registration (PROSPERO) CRD42016033619.
Results
Twenty‐four adult RCTs and 23 of children with type 1 diabetes were included in the systematic review. In aggregate meta‐analysis there was no overall effect of psychological intervention compared with control on HbA1c [adults, nine RCTs, n = 1102, pooled mean difference −0.12, 95% confidence intervals (CI) −0.27 to 0.03, I2 = 29.0%, P = 0.19; children, 20 RCTs, n = 2567, −0.09, 95% CI −0.22 to 0.04, I2=54.0% P=0.002]. Network meta‐analysis suggested that probability and rank‐ordering of effectiveness is highest for attention control groups (b = −0.47, 95% CI −0.80 to −0.12) followed by cognitive behavioural therapy (CBT) (−0.26, 95% CI −0.45 to −0.06) compared with usual care for adults.
Conclusions
Overall psychological interventions for children and adults with type 1 diabetes do not improve glycaemic control. For adults, CBT‐based interventions have the potential to be effective
Calculation of electrostatic fields using quasi-Green's functions: application to the hybrid Penning trap.
Penning traps offer unique possibilities for storing, manipulating and investigating charged particles with high sensitivity and accuracy. The widespread applications of Penning traps in physics and chemistry comprise e.g. mass spectrometry, laser spectroscopy, measurements of electronic and nuclear magnetic moments, chemical sample analysis and reaction studies. We have developed a method, based on the Green's function approach, which allows for the analytical calculation of the electrostatic properties of a Penning trap with arbitrary electrodes. The ansatz features an extension of Dirichlet's problem to nontrivial geometries and leads to an analytical solution of the Laplace equation. As an example we discuss the toroidal hybrid Penning trap designed for our planned measurements of the magnetic moment of the (anti)proton. As in the case of cylindrical Penning traps, it is possible to optimize the properties of the electric trapping fields, which is mandatory for high-precision experiments with single charged particles. Of particular interest are the anharmonicity compensation, orthogonality and optimum adjustment of frequency shifts by the continuous SternGerlach effect in a quantum jump spectrometer. The mathematical formalism developed goes beyond the mere design of novel Penning traps and has potential applications in other fields of physics and engineering
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