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News Article | June 23, 2017
Site: www.eurekalert.org

Deep in space between distant stars, space is not empty. Instead, there drifts vast clouds of neutral atoms and molecules, as well as charged plasma particles called the interstellar medium -- that may, over millions of years, evolve into new stars and even planets. These floating interstellar reservoirs are the focus of the NASA-funded CHESS sounding rocket mission, which will check out the earliest stages of star formation. CHESS -- short for the Colorado High-resolution Echelle Stellar Spectrograph -- is a sounding rocket payload that will fly on a Black Brant IX suborbital sounding rocket early in the morning of June 27, 2017. CHESS measures light filtering through the interstellar medium to study the atoms and molecules within, which provides crucial information for understanding the lifecycle of stars. "The interstellar medium pervades the galaxy," said Kevin France, the CHESS principle investigator at the University of Colorado, Boulder. "When massive stars explode as supernovae, they expel this raw material. It's the insides of dead stars, turning into the next generation of stars and planets." CHESS is a spectrograph, which provides information on how much of any given wavelength of light is present. It will train its eye at Beta Scorpii -- a hot, brightly shining star in the Scorpius constellation well-positioned for the instrument to probe the material between the star and our own solar system. As light from Beta Scorpii streams toward Earth, atoms and molecules -- including carbon, oxygen and hydrogen -- block the light to varying degrees along the way. Scientists know which wavelengths are blocked by what, so by looking at how much light reaches the space around Earth, they can assess all sorts of details about the space it travelled through to get there. CHESS data provides observations such as which atoms and molecules are present in space, their temperatures and how fast they're moving. The scientists also use CHESS data to evaluate how the interstellar cloud is structured, which can help them pinpoint where it stands in the process of star formation. It's still not known exactly how long it takes for this material to be incorporated into new stars. But scientists know dense clouds can pave the way for the collapse at the very beginning of star formation. The flight of a sounding rocket is a short one; CHESS will fly for about 16 minutes total. Just six-and-a-half of those minutes are spent making observations between 90 and 200 miles above the surface -- observations that can only be made in space, above the atmosphere, which the far-ultraviolet light that CHESS observes can't penetrate. After the flight, the payload parachutes to the ground, where it can be recovered for future flights. This is the third flight for the CHESS payload in the past three years, and the mission's most detailed survey yet. The scientists have used each to trial and improve the technology; the upcoming flight sports an upgraded diffraction grating, which reflects light and separates it into its different wavelengths. "A more efficient grating means the instrument is that many times more sensitive," France said. "Compared to the first flight of CHESS, this third incarnation is about eight times more sensitive." By flying rapidly developing instruments on relatively inexpensive sounding rockets, scientists are not only able to acquire high-quality science data, but also test and mature their instruments toward possible spaceflight. According to France, the CHESS instrument serves as a spectrograph prototype for NASA's LUVOIR concept. "Supporting technology and suborbital flight projects today directly translates into lower risk and shorter development time for NASA's large missions in the next two decades," France said. The launch window for CHESS opens at 1:10 a.m. EDT at the White Sands Missile Range near Las Cruces, New Mexico. Precise timing of the launch will depend on weather conditions. CHESS is supported through NASA's Sounding Rocket Program conducted at the agency's Wallops Flight Facility, which is managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland. Orbital ATK provides mission planning, engineering services and field operations for the NASA Sounding Rocket Operations Contract. NASA's Heliophysics Division manages the sounding rocket program for the agency.


Fitzgerald J.,Newcastle University | Pierce K.,Newcastle University | Verhoef M.,Chess
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

This paper presents initial results of research aimed at developing methods and tools for multidisciplinary collaborative development of dependable embedded systems. We focus on the construction and analysis by co-simulation of formal models that combine discrete-event specifications of computer-based controllers with continuous-time models of the environment with which they interact. Basic concepts of collaborative modelling and co-simulation are presented. A pragmatic realisation using the VDM and Bond Graph formalisms is described and illustrated by means of an example, which includes the modelling of both normal and faulty behaviour. Consideration of a larger-scale example from the personal transportation domain suggests the forms of support needed to explore the design space of collaborative models. Based on experience so far, challenges for future research in this area are identified. © 2010 Springer-Verlag Berlin Heidelberg.


PubMed | Epimos GmbH, EAH Consulting, University of Groningen, CHESS and 2 more.
Type: Journal Article | Journal: PharmacoEconomics | Year: 2016

Seasonal influenza infection is primarily caused by circulation of two influenza A strain subtypes and strains from two B lineages that vary each year. Trivalent influenza vaccine (TIV) contains only one of the two B-lineage strains, resulting in mismatches between vaccine strains and the predominant circulating B lineage. Quadrivalent influenza vaccine (QIV) includes both B-lineage strains. The objective was to estimate the cost-utility of introducing QIV to replace TIV in Germany.An individual-based dynamic transmission model (4Flu) using German data was used to provide realistic estimates of the impact of TIV and QIV on age-specific influenza infections. Cases were linked to health and economic outcomes to calculate the cost-utility of QIV versus TIV, from both a societal and payer perspective. Costs and effects were discounted at 3.0 and 1.5% respectively, with 2014 as the base year. Univariate and probabilistic sensitivity analyses were conducted.Using QIV instead of TIV resulted in additional quality-adjusted life-years (QALYs) and cost savings from the societal perspective (i.e. it represents the dominant strategy) and an incremental cost-utility ratio (ICUR) of 14,461 per QALY from a healthcare payer perspective. In all univariate analyses, QIV remained cost-effective (ICUR <50,000). In probabilistic sensitivity analyses, QIV was cost-effective in >98 and >99% of the simulations from the societal and payer perspective, respectively.This analysis suggests that QIV in Germany would provide additional health gains while being cost-saving to society or costing 14,461 per QALY gained from the healthcare payer perspective, compared with TIV.


Das Mahapatra S.,Jadavpur University | Saha D.,Jadavpur University | Saha R.,Jadavpur University | Sanyal D.,Jadavpur University | And 2 more authors.
2016 IEEE 1st International Conference on Control, Measurement and Instrumentation, CMI 2016 | Year: 2016

A Stewart platform that is a 6-DOF parallel manipulator with a moveable frame for three linear and three angular motions has been designed with electrohydraulic actuation for achieving maneuverability of heavy load. A popular application is the motion simulator for an aircraft or a ship that could be used for training by generating specific motions within the confine of a laboratory. The main contribution of this work is the design and realization of a high-precision simulator with low-cost proportional valves using a simple PI controller for achieving basic motions. A pose-feedback controller has been conceived for the system constructed on the basis of the feedback of the leg lengths and a linearized inverse kinematic model about the neutral position. A number of real-time experiments have shown the design to be quite satisfactory. © 2016 IEEE.


Van Vlaenderen I.,CHESS | Van Bellinghen L.-A.,CHESS | Meier G.,Glaxosmithkline | Nautrup B.P.,EAH Consulting
BMC Infectious Diseases | Year: 2013

Background: Indirect herd effect from vaccination of children offers potential for improving the effectiveness of influenza prevention in the remaining unvaccinated population. Static models used in cost-effectiveness analyses cannot dynamically capture herd effects. The objective of this study was to develop a methodology to allow herd effect associated with vaccinating children against seasonal influenza to be incorporated into static models evaluating the cost-effectiveness of influenza vaccination.Methods: Two previously published linear equations for approximation of herd effects in general were compared with the results of a structured literature review undertaken using PubMed searches to identify data on herd effects specific to influenza vaccination. A linear function was fitted to point estimates from the literature using the sum of squared residuals.Results: The literature review identified 21 publications on 20 studies for inclusion. Six studies provided data on a mathematical relationship between effective vaccine coverage in subgroups and reduction of influenza infection in a larger unvaccinated population. These supported a linear relationship when effective vaccine coverage in a subgroup population was between 20% and 80%. Three studies evaluating herd effect at a community level, specifically induced by vaccinating children, provided point estimates for fitting linear equations. The fitted linear equation for herd protection in the target population for vaccination (children) was slightly less conservative than a previously published equation for herd effects in general. The fitted linear equation for herd protection in the non-target population was considerably less conservative than the previously published equation.Conclusions: This method of approximating herd effect requires simple adjustments to the annual baseline risk of influenza in static models: (1) for the age group targeted by the childhood vaccination strategy (i.e. children); and (2) for other age groups not targeted (e.g. adults and/or elderly). Two approximations provide a linear relationship between effective coverage and reduction in the risk of infection. The first is a conservative approximation, recommended as a base-case for cost-effectiveness evaluations. The second, fitted to data extracted from a structured literature review, provides a less conservative estimate of herd effect, recommended for sensitivity analyses. © 2013 Van Vlaenderen et al.; licensee BioMed Central Ltd.


Hooman J.,Embedded Systems Institute | Hooman J.,Radboud University Nijmegen | Verhoef M.,Chess
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

To support model-based development and analysis of embedded systems, the specification language VDM++ has been extended with asynchronous communication and improved timing primitives. In addition, we have defined an interface for the co-simulation of a VDM++ model with a continuous-time model of its environment. This enables multi-disciplinary design space exploration and continuous validation of design decisions throughout the development process. We present an operational semantics which formalizes the precise meaning of the VDM extensions and the co-simulation concept. © 2010 Springer.


Objective: To estimate the potential cost-effectiveness of quadrivalent influenza vaccine compared with trivalent influenza vaccine in the UK. Methods: A lifetime, multi-cohort, static Markov model was constructed, with nine age groups each divided into healthy and at-risk categories. Influenza A and B were accounted for separately. The model was run in one-year cycles for a lifetime (maximum age: 100 years). The analysis was from the perspective of the UK National Health Service. Costs and benefits were discounted at 3.5%. 2010 UK vaccination policy (vaccination of people at risk and those aged ≥65 years) was applied. Herd effect was not included. Inputs were derived from national databases and published sources where possible. The quadrivalent influenza vaccine price was not available when the study was conducted. It was estimated at £6.72,15% above the trivalent vaccine price of £5.85. Sensitivity analyses used an incremental price of up to 50%. Results: Compared with trivalent influenza vaccine, the quadrivalent influenza vaccine would be expected to reduce the numbers of influenza cases by 1,393,720, medical visits by 439,852 complications by 167,357, hospitalisations for complications by 26,424 and influenza deaths by 16,471. The estimated base case incremental cost-effectiveness ratio (ICER) was £5,299/quality-adjusted life-year (QALY). Sensitivity analyses indicated that the ICER was sensitive to changes in circulation of influenza virus subtypes and vaccine mismatch; all other parameters had little effect. In 96% of simulations the ICER was <£20,000/QALY. Since this analysis was completed, quadrivalent influenza vaccine has become available in the UK at a list price of £9.94. Using this price in the model, the estimated ICER for quadrivalent compared with trivalent vaccination was £27,378/QALY, still within the NICE cost-effectiveness threshold (£20,000-£30,000). Conclusions: Quadrivalent influenza vaccine could reduce influenza disease burden and would be cost-effective compared with trivalent influenza vaccine in elderly people and clinical risk groups in the UK. © 2014 Van Bellinghen et al.


Poulsen Nautrup B.,EAH Consulting | Van Vlaenderen I.,CHESS | Gasper S.M.,Zoetis Inc. | Holland R.E.,CHESS
Journal of Animal Science | Year: 2013

The goal of this study was to determine the clinical and economic impact of using tulathromycin as first line treatment for bovine respiratory disease (BRD) compared with other commonly used antimicrobials. Two decision trees were developed simulating the consequences of treating cattle at high risk of developing BRD [control model (CM)] or cattle with first clinical BRD episode [treatment model (TM)]. As comparators florfenicol and tilmicosin were considered in both models whereas enrofloxacin was included in the TM because it was only labeled for treatment of BRD at the time of development of the calculators. A total of 5 (CM) and 10 (TM) comparative clinical studies that reported efficacy data for the selected drugs and indications were identified as suitable for model population. The following outcomes were considered: first treatment success, number of subsequent BRD treatments, chronics, and mortalities. Cost parameters were considered from the perspective of the producer and included treatment costs (first treatment and retreatments) and costs of chronics and deaths derived from published sources for 2010 (default). The models allowed the estimation of clinical and economic consequences according to each individual trial outcomes. Treatment with tulathromycin resulted in more first treatment successes and fewer removals (chronics and deaths) in all comparisons. The average total number of antimicrobial treatments required for the management of BRD was also least with tulathromycin as first treatment option. Because of better efficacy, total costs over the entire study periods were always lowest with tulathromycin. Depending on the study selected as the basis for the efficacy evaluation, cost savings with tulathromycin were calculated in the CM between US$21.00 and $47.86 (vs. florfenicol) and $11.37 and $72.64 (vs. tilmicosin); cost savings in the TM ranged between $28.47 and $143.87 (vs. florfenicol) and $7.75 and $84.91 (vs. tilmicosin) as well as between $23.22 and $47.82 (vs. enrofloxacin), with the ranges reflecting a variety of settings in different trials. Thus, the higher drug costs of tulathromycin were more than offset by reduced BRD treatments, chronics, and mortalities in the herd. Fewer BRD episodes in cattle treated with tulathromycin not only contributes to overall savings in BRD management but also reduces the necessity of repeated antibiotic treatment, supporting prudent use of antimicrobials in livestock. © 2013 American Society of Animal Science. All rights reserved.


Indirect herd effect from vaccination of children offers potential for improving the effectiveness of influenza prevention in the remaining unvaccinated population. Static models used in cost-effectiveness analyses cannot dynamically capture herd effects. The objective of this study was to develop a methodology to allow herd effect associated with vaccinating children against seasonal influenza to be incorporated into static models evaluating the cost-effectiveness of influenza vaccination.Two previously published linear equations for approximation of herd effects in general were compared with the results of a structured literature review undertaken using PubMed searches to identify data on herd effects specific to influenza vaccination. A linear function was fitted to point estimates from the literature using the sum of squared residuals.The literature review identified 21 publications on 20 studies for inclusion. Six studies provided data on a mathematical relationship between effective vaccine coverage in subgroups and reduction of influenza infection in a larger unvaccinated population. These supported a linear relationship when effective vaccine coverage in a subgroup population was between 20% and 80%. Three studies evaluating herd effect at a community level, specifically induced by vaccinating children, provided point estimates for fitting linear equations. The fitted linear equation for herd protection in the target population for vaccination (children) was slightly less conservative than a previously published equation for herd effects in general. The fitted linear equation for herd protection in the non-target population was considerably less conservative than the previously published equation.This method of approximating herd effect requires simple adjustments to the annual baseline risk of influenza in static models: (1) for the age group targeted by the childhood vaccination strategy (i.e. children); and (2) for other age groups not targeted (e.g. adults and/or elderly). Two approximations provide a linear relationship between effective coverage and reduction in the risk of infection. The first is a conservative approximation, recommended as a base-case for cost-effectiveness evaluations. The second, fitted to data extracted from a structured literature review, provides a less conservative estimate of herd effect, recommended for sensitivity analyses.

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