4,197 research outputs found

    Definition of a near real time microbiological monitor for space vehicles

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    Efforts to identify the ideal candidate to serve as the biological monitor on the space station Freedom are discussed. The literature review, the evaluation scheme, descriptions of candidate monitors, experimental studies, test beds, and culture techniques are discussed. Particular attention is given to descriptions of five candidate monitors or monitoring techniques: laser light scattering, primary fluorescence, secondary fluorescence, the volatile product detector, and the surface acoustic wave detector

    Working Memory Deficits in Children: Contributions of Executive Control Processes and Symptoms of ADHD

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    The most empirically supported model of working memory contains four components: (a) the phonological loop, (b) the visuospatial sketchpad, (c) the episodic buffer, and (d) the central executive (Baddeley and Hitch, 1974; Baddeley, 2003). The central executive has been fractionated into four subprocesses: (a) sustained attention, (b) selective attention/inhibition (c) shifting attention, and (d) control of retrieval from long-term memory (Baddeley, 2003; Mirsky et al., 1991; Zoelch et al., 2005). Children with ADHD are known to have working memory deficits, though the role of each component of the working memory system in these deficits is not known. The purpose of the current study is to examine the relationships between (a) symptoms of ADHD and working memory performance, (b) central executive processes and working memory performance, and (c) the unique contributions of each fractionated central executive component to the relationship between symptoms of ADHD and working memory performance. 85 children ages 8 to 16 from an outpatient clinical database were included in the study sample. Sustained attention was found to contribute unique variance to working memory performance after controlling for short-term memory. Selective attention/inhibition, shifting attention, and control of retrieval from long-term memory did not contribute unique variance to working memory, though limited power may have affected results. ADHD symptoms did not correlate with working memory, but they did correlate with short-term memory. Sustained attention was then examined as a mediator between ADHD hyperactivity symptoms and short-term memory. Though not a significant mediator, results of mediation procedures appear to indicate partial mediation. Results indicate that sustained attention may be a fractionated process of the central executive. They also suggest that ADHD symptoms may interfere with working memory at the short-term memory and executive levels. Further investigation is suggested to explain relationships between executive processes and working memory performance and between symptoms of ADHD and all components of the working memory system

    Study of methane fuel for subsonic transport aircraft

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    The cost and performance were defined for commercial transport using liquid methane including its fuel system and the ground facility complex required for the processing and storage of methane. A cost and performance comparison was made with Jet A and hydrogen powered aircraft of the same payload and range capability. Extensive design work was done on cryogenic fuel tanks, insulation systems as well as the fuel system itself. Three candidate fuel tank locations were evaluated, i.e., fuselage tanks, wing tanks or external pylon tanks

    Obes Rev

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    The goals of this systematic review were to identify and describe paediatric obesity prevention interventions from infancy to late adolescence and to provide recommendations for future intervention research in light of a recently proposed developmental cascade (DC) model of paediatric obesity. We conducted an electronic search of randomized controlled trials with a minimum 6-month postintervention follow-up published between 1995 and 2019. We included 74 interventions: prenatal/infancy (n = 4), early childhood (n = 11), childhood (n = 38), early to mid-adolescence (n = 18), and late adolescence (n = 3). Infancy and early childhood trials targeted early feeding and positive parenting skills. Half of the childhood and adolescence trials were school based and used universal prevention strategies; those classified as selective or indicated prevention tended to involve the family for more intensive lifestyle modification. Less than 10% of studies followed participants over long periods of time (greater than or equal to 5 years), and only 16% and 31% of studies assessed intervention mediators and moderators, respectively. We recommend that future interventions focus on early prevention, assess long-term intervention effects, use a standardized taxonomy for defining intervention behavioural strategies, assess underlying mechanisms of action and intervention moderators, target parent and family management strategies across development, and increase scientific equity. We also provide specific recommendations regarding intervention targets for each developmental stage.R01 MD007724/MD/NIMHD NIH HHS/United StatesDP006255/National Center for Chronic Disease Prevention and Health Promotion of the Centers of Disease Control and Prevention/2018-68001-27550/DP/NCCDPHP CDC HHS/United StatesU18DP006255/ACL/ACL HHS/United StatesU18 DP006255/DP/NCCDPHP CDC HHS/United States016-10799/United States Department of Agriculture/K01 HL133521/HL/NHLBI NIH HHS/United States2021-02-01T00:00:00Z31808277PMC69808927148vault:3452

    STUDY OF PRESSURE AND COMPOSITION EFFECT ON MULTICOMPONENT MEMBRANE SEPARATION INVOLVING HEAVY HYDROCARBON GAS PENTANE

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    This work study the performance and characterize polyimide hollow fiber membranes for the separation of CO2-CH- C5H12 at difference pressure and feed composition as well as the effect of heavy hydrocarbon gas C5H12 on membrane performance. In Malaysia, approximately 13 trillion ft³ of high CO2 natural gas field are uneconomical to be developed. Development of high CO2 gas fields requires prudent management of carbon dioxide capture, transportation, and storage to enable commercialization of these fields. Research conducted on CO2 separation using membrane is limited especially on multicomponent and involving heavy hydrocarbon gas. Scope of experimental study focus on pure gas, gas mixture with and without heavy hydrocarbon gas C5H12 as well as varies the feed pressure from 10 bar to 18 bar and CO2 feed composition from 10% to 90%. Research methodologies include fabrication of membrane module, membrane characterization using FTIR, FESEM, and performances testing with CO2SMU and GC. FTIR finding show that membrane matrix’s polar sites enhance the preferential interaction and solubility of CO2 gas molecules, resulting in higher CO2 permeates flow compare to CH4 & C5H12. Decrease in flux, permeance and CO2 relative permeance is observed in gas mixture feed especially with present of heavy hydrocarbon gas C5H12. C5H12. As feed pressure increase, driving force increase preferentially sorbed of CO2 gas increase CO2 flux significantly, while CH4 and C5H12 flux only increase marginally. Furthermore, membrane layer compaction and plasticization increase CO2 permeance and relative permeance. As CO2 feed composition increase, membrane plasticize more, increasing preferentially sorbed of CO2 gas at matrix’s polar sites, thus increasing CO2 flux and permeance while, CH4 and C5H12 flux and permeance remain constant. So, CO2 relative permeance increases. In the nutshell, polyimide hollow fiber membranes show promising performance for separation of CO2-CH- C5H12 and experimental findings can be used for Multicomponent Hollow Fiber Membrane Module Performance Prediction Program (HFM3P)

    Promoting physical activity among university students: a systematic review of controlled trials

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    Objective: University study is often accompanied by a decline in physical activity (PA) levels but can offer the opportunity to promote a lifelong active lifestyle. This review aims to summarize controlled trials of interventions promoting PA among uni- versity students, describing the quality of the evidence, effective strategies, and deficiencies in the interventions employed, to provide directions for future research and for practical implementations. Data Source: PubMed, PsychINFO, Cochrane Library, Education Source, and SPORTDiscus. Study Inclusion Criteria: Randomized or nonrandomized controlled trial, describing an intervention to promote PA in uni- versity students, where PA was one of the outcomes and results were published in English. Data Extraction: Country, study design, participants\u2019 inclusion criteria, participation rate and characteristics, randomization, blinding, theoretical framework, intervention characteristics, participant retention rate and withdrawal reasons, measures employed, data analysis, PA results, and findings regarding PA correlates. Data Synthesis: Data were synthetized considering study characteristics, strategies used, and outcomes. Results: Two thousand five hundred eighty-five articles were identified. Twenty-seven studies met the inclusion criteria. Sixteen studies reported an increase in PA levels. Conclusion: Physical Activity promotion interventions should address a range of behavioral determinants. Personalized approaches and PA sessions should be considered in future studies. The high risk of bias of many studies (mainly due to attrition and poor reporting) and missing information about intervention components limit the strength of conclusions about the most effective strategies and the evidence of effectiveness, highlighting the need for further high-quality studies

    Aerospace medicine and biology: A continuing bibliography with indexes (supplement 334)

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    This bibliography lists 254 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during February, 1990. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

    Chapter Life Cycle Assessment as a Tool to Implement Sustainable Development in the Bioeconomy and Circular Economy

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    In this chapter, the life cycle assessment was presented as a tool to implement sustainable development in the bioeconomy and circular economy. Bulky waste includes large items such as furniture, doors, flooring and mattresses. The management of bulky waste is a serious problem for European countries. The URBANREC project proposed a solution to this problem through the use of new technologies for the bulky waste processing. The aim of the URBANREC project is to implement an eco-innovative, integrated system of bulky waste management and demonstrate its effectiveness in various regions of Europe. The project has received funding from the European Union. In this chapter, the LCA environmental analysis was performed for the technology of grinding bulky waste using a water jet by the Ecofrag company. The calculations were carried out using SimaPro 8.5.2.0. The LCA analysis shows that the reuse of foams and mattresses contributes to the avoidance of their targeted production, which is related with the reduction of greenhouse gas emission and consumption of fossil raw materials

    Life Cycle Assessment as a Tool to Implement Sustainable Development in the Bioeconomy and Circular Economy

    Get PDF
    In this chapter, the life cycle assessment was presented as a tool to implement sustainable development in the bioeconomy and circular economy. Bulky waste includes large items such as furniture, doors, flooring and mattresses. The management of bulky waste is a serious problem for European countries. The URBANREC project proposed a solution to this problem through the use of new technologies for the bulky waste processing. The aim of the URBANREC project is to implement an eco-innovative, integrated system of bulky waste management and demonstrate its effectiveness in various regions of Europe. The project has received funding from the European Union. In this chapter, the LCA environmental analysis was performed for the technology of grinding bulky waste using a water jet by the Ecofrag company. The calculations were carried out using SimaPro 8.5.2.0. The LCA analysis shows that the reuse of foams and mattresses contributes to the avoidance of their targeted production, which is related with the reduction of greenhouse gas emission and consumption of fossil raw materials
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