50 research outputs found
Endovascular aneurysm repair offers a survival advantage and is cost-effective compared to conservative management in patients physiologically unfit for open repair
Objective
The EVAR-2 trial suggested that endovascular aneurysm repair (EVAR) in patients unfit for open surgical repair (OSR) failed to provide a significant overall survival advantage compared to conservative management. The aim is to compare survival and cost-effectiveness in patients with poor cardiopulmonary exercise test (CPET) metrics who underwent EVAR or were managed conservatively.
Methods
A prospective database of all CPETs (1435 patients) performed to assess preoperative fitness for abdominal aortic aneurysm (AAA) repair was maintained. 350 patients deemed unfit for (OSR) underwent EVAR or were managed conservatively. A 1:1 propensity-matched analysis incorporating age, gender, anaerobic threshold (AT) and aneurysm size was used to compare survival. Cost-effectiveness analysis (CEA) was based on the economic model for the National Institute for Health and Care Excellence (NICE) clinical guideline on AAA treatment.
Results
Propensity matching produced 122 pairs of patients in the EVAR and conservative management groups. The median overall survival for the EVAR group was significantly longer than the conservative management group (84 versus 30 months, p<0.001). 1, 3 and 5-year mortality in the EVAR group was 7%, 40% and 68%, respectively, compared to 25%, 68% and 82% in the conservative management group, all p<0.001. Increment cost-effectiveness ratio (ICER) for EVAR was ÂŁ8,023 (US 624,967) in the NICE Guideline, which is based on EVAR-2 results.
Conclusion
EVAR offers a survival advantage and is cost-effective in selected patients deemed unfit for OSR based on CPET compared to conservative management
The calibration of the Sudbury Neutrino Observatory using uniformly distributed radioactive sources
The production and analysis of distributed sources of 24Na and 222Rn in the
Sudbury Neutrino Observatory (SNO) are described. These unique sources provided
accurate calibrations of the response to neutrons, produced through
photodisintegration of the deuterons in the heavy water target, and to low
energy betas and gammas. The application of these sources in determining the
neutron detection efficiency and response of the 3He proportional counter
array, and the characteristics of background Cherenkov light from trace amounts
of natural radioactivity is described.Comment: 24 pages, 13 figure
Data visualization in yield component analysis: an expert study
Even though data visualization is a common analytical tool in numerous disciplines, it has rarely been used in agricultural sciences, particularly in agronomy. In this paper, we discuss a study on employing data visualization to analyze a multiplicative model. This model is often used by agronomists, for example in the so-called yield component analysis. The multiplicative model in agronomy is normally analyzed by statistical or related methods. In practice, unfortunately, usefulness of these methods is limited since they help to answer only a few questions, not allowing for a complex view of the phenomena studied. We believe that data visualization could be used for such complex analysis and presentation of the multiplicative model. To that end, we conducted an expert survey. It showed that visualization methods could indeed be useful for analysis and presentation of the multiplicative model
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Tests of Lorentz invariance at the Sudbury Neutrino Observatory
Experimental tests of Lorentz symmetry in systems of all types are critical for ensuring that the basic assumptions of physics are well founded. Data from all phases of the Sudbury Neutrino Observatory, a kiloton-scale heavy water Cherenkov detector, are analyzed for possible violations of Lorentz symmetry in the neutrino sector. Such violations would appear as one of eight possible signal types in the detector: six seasonal variations in the solar electron neutrino survival probability differing in energy and time dependence and two shape changes to the oscillated solar neutrino energy spectrum. No evidence for such signals is observed, and limits on the size of such effects are established in the framework of the standard model extension, including 38 limits on previously unconstrained operators and improved limits on 16 additional operators. This makes limits on all minimal, Dirac-type Lorentz violating operators in the neutrino sector available for the first time
Observation of inverse Compton emission from a long Îł-ray burst.
Long-duration Îł-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectronvolt-to-megaelectronvolt band, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission1,2. Subsequently, the interaction of the jet with the surrounding medium generates shock waves that are responsible for the afterglow emission, which lasts from days to months and occurs over a broad energy range from the radio to the gigaelectronvolt bands1-6. The afterglow emission is generally well explained as synchrotron radiation emitted by electrons accelerated by the external shock7-9. Recently, intense long-lasting emission between 0.2 and 1 teraelectronvolts was observed from GRB 190114C10,11. Here we report multi-frequency observations of GRB 190114C, and study the evolution in time of the GRB emission across 17 orders of magnitude in energy, from 5 Ă 10-6 to 1012 electronvolts. We find that the broadband spectral energy distribution is double-peaked, with the teraelectronvolt emission constituting a distinct spectral component with power comparable to the synchrotron component. This component is associated with the afterglow and is satisfactorily explained by inverse Compton up-scattering of synchrotron photons by high-energy electrons. We find that the conditions required to account for the observed teraelectronvolt component are typical for GRBs, supporting the possibility that inverse Compton emission is commonly produced in GRBs
Review of the techniques used in motorâcognitive humanârobot skill transfer
Abstract A conventional robot programming method extensively limits the reusability of skills in the developmental aspect. Engineers programme a robot in a targeted manner for the realisation of predefined skills. The low reusability of generalâpurpose robot skills is mainly reflected in inability in novel and complex scenarios. Skill transfer aims to transfer human skills to generalâpurpose manipulators or mobile robots to replicate humanâlike behaviours. Skill transfer methods that are commonly used at present, such as learning from demonstrated (LfD) or imitation learning, endow the robot with the expert's lowâlevel motor and highâlevel decisionâmaking ability, so that skills can be reproduced and generalised according to perceived context. The improvement of robot cognition usually relates to an improvement in the autonomous highâlevel decisionâmaking ability. Based on the idea of establishing a generic or specialised robot skill library, robots are expected to autonomously reason about the needs for using skills and plan compound movements according to sensory input. In recent years, in this area, many successful studies have demonstrated their effectiveness. Herein, a detailed review is provided on the transferring techniques of skills, applications, advancements, and limitations, especially in the LfD. Future research directions are also suggested
Measurement of the Îœe and total 8B solar neutrino fluxes with the Sudbury Neutrino Observatory phase-III data set
This paper details the solar neutrino analysis of the 385.17-day phase-III data set acquired by the Sudbury Neutrino Observatory (SNO). An array of 3He proportional counters was installed in the heavy-water target to measure precisely the rate of neutrino-deuteron neutral-current interactions. This technique to determine the total active 8B solar neutrino flux was largely independent of the methods employed in previous phases. The total flux of active neutrinos was measured to be 5.54-0.31+0.33(stat.)-0.34+0.36(syst.)Ă106 cm-2 s-1, consistent with previous measurements and standard solar models. A global analysis of solar and reactor neutrino mixing parameters yielded the best-fit values of Îm2=7.59-0.21+0.19Ă10 -5eV2 and Ξ=34.4-1.2+1.3degrees
A joint Fermi-GBM and Swift-BAT analysis of gravitational-wave candidates from the third gravitational-wave observing run
We present Fermi Gamma-ray Burst Monitor (Fermi-GBM) and Swift Burst Alert Telescope (Swift-BAT) searches for gamma-ray/X-ray counterparts to gravitational-wave (GW) candidate events identified during the third observing run of the Advanced LIGO and Advanced Virgo detectors. Using Fermi-GBM onboard triggers and subthreshold gamma-ray burst (GRB) candidates found in the Fermi-GBM ground analyses, the Targeted Search and the Untargeted Search, we investigate whether there are any coincident GRBs associated with the GWs. We also search the Swift-BAT rate data around the GW times to determine whether a GRB counterpart is present. No counterparts are found. Using both the Fermi-GBM Targeted Search and the Swift-BAT search, we calculate flux upper limits and present joint upper limits on the gamma-ray luminosity of each GW. Given these limits, we constrain theoretical models for the emission of gamma rays from binary black hole mergers