13kW Advanced Electric Propulsion Flight System Development and Qualification

The next phase of robotic and human deep space exploration missions is enhanced by high performance, high power solar electric propulsion systems for large-scale science missions and cargo transportation. Aerojet Rocketdynes Advanced Electric Propulsion System (AEPS) program is completing development, qualification and delivery of five flight 13.3kW EP systems to NASA. The flight AEPS includes a magnetically-shielded, long-life Hall thruster, power processing unit (PPU), xenon flow controller (XFC), and intrasystem harnesses. The Hall thruster, originally developed and demonstrated by NASAs Glenn Research Center and the Jet Propulsion Laboratory, operates at input powers up to 12.5kW while providing a specific impulse over 2600s at an input voltage of 600V. The power processor is designed to accommodate an input voltage range of 95 to 140V, consistent with operation beyond the orbit of Mars. The integrated system is continuously throttleable between 3 and 13.3kW. The program has completed the system requirement review; the system, thruster, PPU and XFC preliminary design reviews; development of engineering models, and initial system integration testing. This paper will present the high power AEPS capabilities, overall program and design status and the latest test results for the 13.3kW flight system development and qualification program

Prescription of respiratory medication without an asthma diagnosis in children: a population based study

Background. In pre-school children a diagnosis of asthma is not easily made and only a minority of wheezing children will develop persistent atopic asthma. According to the general consensus a diagnosis of asthma becomes more certain with increasing age. Therefore the congruence between asthma medication use and doctor-diagnosed asthma is expected to increase with age. The aim of this study is to evaluate the relationship between prescribing of asthma medication and doctor-diagnosed asthma in children age 0-17. Methods. We studied all 74,580 children below 18 years of age, belonging to 95 GP practices within the second Dutch national survey of general practice (DNSGP-2), in which GPs registered all physician-patient contacts during the year 2001. Status on prescribing of asthma medication (at least one prescription for beta2-agonists, inhaled corticosteroids, cromones or montelukast) and doctor-diagnosed asthma (coded according to the International Classification of Primary Care) was determined. Results. In total 7.5% of children received asthma medication and 4.1% had a diagnosis of asthma. Only 49% of all children receiving asthma medication was diagnosed as an asthmatic. Subgroup analyses on age, gender and therapy groups showed that the Positive Predictive Value (PPV) differs significantly between therapy groups only. The likelihood of having doctor-diagnosed asthma increased when a child received combination therapy of short acting beta2-agonists and inhaled corticosteroids (PPV = 0.64) and with the number of prescriptions (3 prescriptions or more, PPV = 0.66). Both prescribing of asthma medication and doctor-diagnosed asthma declined with age but the congruence between the two measures did not increase with age. Conclusion. In this study, less than half of all children receiving asthma medication had a registered diagnosis of asthma. Detailed subgroup analyses show that a diagnosis of asthma was present in at most 66%, even in groups of children treated intensively with asthma medication. Although age strongly influences the chance of being treated, remarkably, the congruence between prescribing of asthma medication and doctor-diagnosed asthma does not increase with age

Induction of Asthma and the Environment: What We Know and Need to Know

The prevalence of asthma has increased dramatically over the last 25 years in the United States and in other nations as a result of ill-defined changes in living conditions in modern society. On 18 and 19 October 2004 the U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences sponsored the workshop “Environmental Influences on the Induction and Incidence of Asthma” to review current scientific evidence with respect to factors that may contribute to the induction of asthma. Participants addressed two broad questions: a) What does the science suggest that regulatory and public health agencies could do now to reduce the incidence of asthma? and b) What research is needed to improve our understanding of the factors that contribute to the induction of asthma and our ability to manage this problem? In this article (one of four articles resulting from the workshop), we briefly characterize asthma and its public health and economic impacts, and intervention strategies that have been successfully used to prevent induction of asthma in the workplace. We conclude with the findings of seven working groups that focus on ambient air, indoor pollutants (biologics), occupational exposures, early life stages, older adults, intrinsic susceptibility, and lifestyle. These groups found strong scientific support for public health efforts to limit in utero and postnatal exposure to cigarette smoke. However, with respect to other potential types of interventions, participants noted many scientific questions, which are summarized in this article. Research to address these questions could have a significant public health and economic impact that would be well worth the investment

Construction of the Pediatric Asthma Impact Scale (PAIS) for the Patient-Reported Outcomes Measurement Information System (PROMIS)

Recently, the National Institutes of Health Roadmap for Medical Research initiative led a large-scale effort to develop the Patient-Reported Outcomes Measurement Information System (PROMIS). PROMIS’s main goal was to develop a set of item banks and computerized adaptive tests for the clinical research community. Asthma, as the most common chronic childhood disease, was chosen for a disease-specific pediatric item bank

PROMIS Pediatric Pain Interference Scale: An Item Response Theory Analysis of the Pediatric Pain Item Bank

An aim of the National Institutes of Health (NIH) Patient Reported Outcomes Measurement Information System (PROMIS) initiative is to develop item banks and computerized adaptive tests (CAT) that are applicable across a wide variety of chronic disorders. The PROMIS Pediatric Cooperative Group has concentrated on the development of pediatric self-report item banks for ages 8-17 years. The objective of the present study is to describe the Item Response Theory (IRT) analysis of the NIH PROMIS pediatric pain item bank and the measurement properties of the new unidimensional PROMIS Pediatric Pain Interference Scale. Test forms containing pediatric pain items were completed by a total of 3,048 respondents. IRT analyses regarding scale dimensionality, item local dependence, and differential item functioning were conducted. A pain item pool was developed to yield scores on a T-score scale with a mean of 50 and standard deviation of 10. The recommended 8-item unidimensional short form for the PROMIS Pediatric Pain Interference Scale contains the item set which provides the maximum test information at the mean (50) on the T-score metric. A simulated CAT was computed that provides the most information at five possible score locations (30, 40, 50, 60, and 70 on the T-score metric)

Sampling plan and patient characteristics of the PROMIS pediatrics large-scale survey

This paper describes a large-scale administration of the Patient-Reported Outcomes Measurement Information System (PROMIS) pediatric items to evaluate measurement characteristics

Conducting Environmental Health Research in the Arabian Middle East: Lessons Learned and Opportunities

Background: The Arabian Gulf nations are undergoing rapid economic development, leading to major shifts in both the traditional lifestyle and the environment. Although the pace of change is brisk, there is a dearth of environmental health research in this region

Cognitive interviewing methodology in the development of a pediatric item bank: a patient reported outcomes measurement information system (PROMIS) study

<p>Abstract</p> <p>Background</p> <p>The evaluation of patient-reported outcomes (PROs) in health care has seen greater use in recent years, and methods to improve the reliability and validity of PRO instruments are advancing. This paper discusses the cognitive interviewing procedures employed by the Patient Reported Outcomes Measurement Information System (PROMIS) pediatrics group for the purpose of developing a dynamic, electronic item bank for field testing with children and adolescents using novel computer technology. The primary objective of this study was to conduct cognitive interviews with children and adolescents to gain feedback on items measuring physical functioning, emotional health, social health, fatigue, pain, and asthma-specific symptoms.</p> <p>Methods</p> <p>A total of 88 cognitive interviews were conducted with 77 children and adolescents across two sites on 318 items. From this initial item bank, 25 items were deleted and 35 were revised and underwent a second round of cognitive interviews. A total of 293 items were retained for field testing.</p> <p>Results</p> <p>Children as young as 8 years of age were able to comprehend the majority of items, response options, directions, recall period, and identify problems with language that was difficult for them to understand. Cognitive interviews indicated issues with item comprehension on several items which led to alternative wording for these items.</p> <p>Conclusion</p> <p>Children ages 8–17 years were able to comprehend most item stems and response options in the present study. Field testing with the resulting items and response options is presently being conducted as part of the PROMIS Pediatric Item Bank development process.</p

Development and psychometric properties of the PROMIS® pediatric fatigue item banks

This paper reports on the development and psychometric properties of self-reported pediatric fatigue item banks as part of the Patient Reported Outcomes Measurement Information System (PROMIS)