1,064 research outputs found

    Asymptotic defectiveness of manufacturing plants: an estimate based on process learning curves

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    The paper describes a method for a preliminary estimation of asymptotic defectiveness of a manufacturing plant based on the prediction of its learning curve estimated during a p-chart setting up. The proposed approach provides process managers with the possibility of estimating the asymptotic variability of the process and the period of revision of p-chart control limits. An application of the method is also provided

    Meal Replacement Mass Reduction Integration and Acceptability Study

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    The Orion Multi-Purpose Crew Vehicle (MPCV) and future exploration missions are mass constrained; therefore we are challenged to reduce the mass of the food system by 10% while maintaining safety, nutrition, and acceptability to support crew health and performance for exploration missions. Meal replacement with nutritionally balanced, 700-900 calorie bars was identified as a method to reduce mass. However, commercially available products do not meet the requirements for a meal replacement in the spaceflight food system. The purpose of this task was to develop a variety of nutritionally balanced, high quality, breakfast replacement bars, which enable a 10% food mass savings. To date, six nutrient-dense meal replacement bars have been developed, all of which meet spaceflight nutritional, microbiological, sensory, and shelf-life requirements. The four highest scoring bars were evaluated based on final product sensory acceptability, nutritional stability, qualitative stability of analytical measurements (i.e. color and texture), and microbiological compliance over a period of two years to predict long-term acceptability. All bars maintained overall acceptability throughout the first year of storage, despite minor changes in color and texture. However, added vitamins C, B1, and B9 degraded rapidly in fortified samples of Banana Nut bars, indicating the need for additional development. In addition to shelf-life testing, four bar varieties were evaluated in the Human Exploration Research Analog (HERA), campaign 3, to assess the frequency with which actual meal replacement options may be implemented, based on impact to satiety and psychosocial measurements. Crewmembers (n=16) were asked to consume meal replacement bars every day for the first fifteen days of the mission and every three days for the second half of the mission. Daily surveys assessed the crew's responses to bar acceptability, mood, food fatigue and perceived stress. Preliminary results indicate that the majority of crew members were noncompliant with daily meal replacement during the first half of the mission. Several crew members chose to forgo the meal, resulting in caloric deficits that were higher on skipped-bar days. Body mass loss was significant throughout the mission. Although there was no significant difference in body mass loss overall between the first half and second half of the mission, a higher number of individual crew members lost more body mass in the first half of the mission. Analysis is still ongoing, but current trends suggest that daily involuntary meal replacement can lead to greater individual impacts on body mass and psychological factors, while meal replacement on a more limited basis may be acceptable to most crew for missions up to 30 days. This data should be considered in Orion mass trades with health and human performance

    Overview of NASA Behavioral Health and Performance Standard Measures

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    NASAs Human Research Program (HRP) is developing a set of Standard Measures for use in spaceflight and spaceflight analog environments to monitor the risks of long-duration missions on human health and performance, including behavioral health, individual and team performance, and social processes. Based on measures selected, developed, and tested under the NASA-funded Behavioral Core Measures project (PI: D.F. Dinges) as well as other projects from NASAs Human Factors & Behavioral Performance research portfolio, NASAs Behavioral Health & Performance (BHP) Laboratory is further evaluating the operational feasibility, acceptability, and validity of a multidisciplinary suite of objective, subjective, behavioral, and biological measures for monitoring monitor behavioral health, individual and team performance, and social processes over time. The inaugural generation of the NASA Behavioral Health & Performance (BHP) Standard Measures includes a neurocognitive test battery, actigraphy, physical proximity sensors, cardiovascular monitors, and subjective self-reports of mood, depression, and various team and social processes and performance outcomes

    A System Dynamics Approach for Modeling Return on Quality for ECS Industry

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    The Electronic Components and Systems industry (ECS) is characterized by long lead times and high market volatility. Besides fast technological development within this industry, cyclic market up- and downturns are influencing the semiconductor market. Therefore, adequate capacity and inventory management as well as continuous process improvements are important success factors for semiconductor companies to be competitive. In this study, the authors focus on a manufacturing excellence approach to increase front-end supply reliability and the availability of inventory within the customer order decoupling point. Here, development and manufacturing processes must be designed in a way that highest levels of product quality, flexibility, time and costs are reached. The purpose of this study is to explore the impact of return on quality in manufacturing systems. Therefore, multimethod simulation modelling including discrete-event and system dynamics simulation is applied

    Meal Replacement Mass Reduction and Integration Acceptability Study

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    NASA, in planning for long duration missions, has an imperative to provide a food system with the necessary nutrition, acceptability, and safety to ensure sustainment of crew health and performance. The Orion Multi-Purpose Crew Vehicle (MPCV) and future exploration missions are mass constrained; therefore we are challenged to reduce the mass of the food system by 10% while maintaining safety, nutrition, and acceptability for exploration missions. Food bars have previously been used to supplement meals in the Skylab food system, indicating that regular consumption of bars will be acceptable. However, commercially available products do not meet the requirements for a full meal replacement in the spaceflight food system. The purpose of this task is to develop a variety of nutritionally balanced breakfast replacement bars, which meet spaceflight nutritional, microbiological, sensorial, and shelf-life requirements, while enabling a 10% food mass savings. To date, six nutrient-dense meal replacement bars have been developed, using both traditional methods of compression as well as novel ultrasonic compression technologies developed by Creative Resonance Inc. (Phoenix, AZ). All bars will be prioritized based on acceptability and the four top candidates will be evaluated in the Human Exploration Research Analog (HERA) to assess the frequency with which actual meal replacement options may be implemented. Specifically, overall impact to mood, satiety, dietary discomfort, and satisfaction with food will be analyzed to inform successful implementation strategies. In addition, these bars will be evaluated based on final product sensory acceptability, nutritional stability, qualitative stability of analytical measurements (i.e. water activity and texture), and microbiological compliance over two years of storage at room temperature and potential temperature abuse conditions to predict long-term acceptability. It is expected that this work will enable a successful meal replacement strategy to be implemented that maintains crew food consumption and health, while informing exploration missions with appropriate mass savings expectations

    Moral Distress Amongst American Physician Trainees Regarding Futile Treatments at the End of Life: A Qualitative Study.

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    BACKGROUND: Ethical challenges are common in end of life care; the uncertainty of prognosis and the ethically permissible boundaries of treatment create confusion and conflict about the balance between benefits and burdens experienced by patients. OBJECTIVE: We asked physician trainees in internal medicine how they reacted and responded to ethical challenges arising in the context of perceived futile treatments at the end of life and how these challenges contribute to moral distress. DESIGN: Semi-structured in-depth qualitative interviews. PARTICIPANTS: Twenty-two internal medicine residents and fellows across three American academic medical centers. APPROACH: This study uses systematic qualitative methods of data gathering, analysis and interpretation. KEY RESULTS: Physician trainees experienced significant moral distress when they felt obligated to provide treatments at or near the end of life that they believed to be futile. Some trainees developed detached and dehumanizing attitudes towards patients as a coping mechanism, which may contribute to a loss of empathy. Successful coping strategies included formal and informal conversations with colleagues and superiors about the emotional and ethical challenges of providing care at the end of life. CONCLUSIONS: Moral distress amongst physician trainees may occur when they feel obligated to provide treatments at the end of life that they believe to be futile or harmful.This study was funded by the Health Resources and Service Administration T32 HP10025-20 Training Grant, the Gates Cambridge Scholarship, Society of General Internal Medicine Founders Grant, and the Ho-Chiang Palliative Care Research Fellowship at the Johns Hopkins School of Medicine.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s11606-015-3505-
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