55 research outputs found

    The Passive Optical Sample Assembly (POSA): I Experiment: First Flight Results and Conclusions

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    The Passive Optical Sample Assembly-I (POSA-I), part of the Mir Environmental Effects Payload (MEEP), was designed to study the combined effects of contamination, atomic oxygen, ultraviolet radiation, vacuum, thermal cycling, and other constituents of the space environment on spacecraft materials. The MEEP program is a Phase 1 International Space Station Risk Mitigation Experiment. SSP 30258 "Thermal Control Architectural Control Document", section 3.1.2 requires that International Space Station (ISS) external materials meet performance requirements when exposed to the external environment as defined in SSP 30426, "Space Station External Contamination Control Requirements." Contamination control documents call for less than 3 x 10(exp -7) gm/sq cm/yr of molecular contamination on a surface at 300 K at the Prime Measurement Points during quiescent periods and less than 1 x 10(exp-6) gm/sq cm/yr during non-quiescent periods. Assuming a density of 1.0 g/cu cm for the contaminant, this is roughly equivalent to 30-100 A per year. A previous Mir flight experiment (Guillaumon et al. 1991) measured 321-716 A per year. Were this to happen on ISS, the radiators would reach end-of-life properties much sooner than the planned 10 years. Therefore, POSA was proposed to expose ISS-baselined materials (such as Z93 white thermal control paint and chromic acid anodized aluminum) to the Mir environment and determine not only the level of contamination from an orbiting, active space station but also the effect of contamination on thermal optical properties. POSA-I consisted of nearly 400 samples of various candidate materials for ISS. Paint samples flown included Z-93 and YB-71 white thermal control paints and a new inorganic bright yellow paint htat can be utilized for astronaut visual aids

    Effects of atomic oxygen on polymeric materials flown on EOIM-3

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    Diverse polymeric materials, including several variations of Kapton, were flown on STS-46 as part of the Evaluation of Oxygen Interaction with Materials Experiment (EOIM-3). These materials were flown in the cargo bay and exposed to the space environment July 31 - August 8, 1992, including 40 hours of direct atomic oxygen impingement. The atomic oxygen exposure was approximately 2.2 x 10(exp 20) atoms/sq cm. Polymeric materials flown on EOIM-3 include coated and uncoated Kapton, Tefzel ETFE, Lexan, FEP and TFE Teflon, bulk Halar and PEEK, S383 silicone and Viton elastomeric seal material. Analyses performed included thickness measurements using Dektak and eddy current methods, mass loss, resistance, permeability, hardness, and FTIR. The effects of stress and the space environment on Kapton were also evaluated. Previous EOIM missions on STS-5 and STS-8 and the Long Duration Exposure Facility also contained polymeric material samples. Data from these previous flights are shown for comparison, as well as ground simulation of space environment effects using both thermal energy flow tubes and 5 eV neutral atomic oxygen beam facilities. Reaction efficiencies for the various atomic oxygen exposure conditions are discussed

    Thermal control materials on EOIM-3

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    Thermal control paints, anodized aluminum, and beta cloth samples were flown on STS-46 as part of the Evaluation of Oxygen Interaction with Materials Experiment (EOIM-3). The thermal control paints flown on EOIM-3 include ceramic and polyurethane-based paints. Passively exposed samples are compared to actively heated samples and controlled exposure samples. Optical property measurements of absorptivity, emissivity, and spectrofluorescence are presented for each paint. Several variations of anodized aluminum, including chromic acid anodize, sulfuric acid anodize, and boric/sulfuric acid anodize were flown on the actively heated trays and the passive exposure trays. The post-flight optical properties are within tolerances for these materials. Also flown were two samples of yellow anodized aluminum. The yellow anodized aluminum samples darkened noticeably. Samples of aluminized and unaluminized beta cloth, a fiberglass woven mat impregnated with TFE Teflon, were flown with passive exposure to the space environment. Data from this part of the experiment is correlated to observations from LDEF and erosion of the Teflon thin film samples also flown on EOIM-3 and LDEF

    Evaluation of space environmental effects on metals and optical thin films on EOIM-3

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    Metals and optical thin films exposed to the space environment on the Third Flight of the Evaluation of Oxygen Interactions with Materials (EOIM-3) payload, onboard Space Shuttle mission STS-46 were evaluated. The materials effects described in this paper include the effects of space exposure on various pure metals, optical thin films, and optical thin film metals. The changes induced by exposure to the space environment in the material properties were evaluated using bidirectional reflectance distribution function (BRDF), specular reflectance (250 nm to 2500 nm), ESCA, VUV reflectance (120 nm to 200 nm), ellipsometry, FTIR and optical properties. Using these analysis techniques gold optically thin film metal mirrors with nickel undercoats were observed to darken due to nickel diffusion through the gold to the surface. Also, thin film nickel mirrors formed nickel oxide due to exposure to both the atmosphere and space

    Politics, policies, and patient care: Rehabilitation therapists' experiences during the COVID-19 Pandemic

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    The year 2020 represents a historically turbulent period for the United States marked by the COVID-19 pandemic, a contentious political season, and heightened awareness of racism among citizens. This intersection of medicine, politics, and social unrest generated a demanding clinical environment for healthcare workers, including understudied groups such as physical therapists, occupational therapists, and speech-language pathologists. This descriptive qualitative study focused on experiences and perspectives of clinical rehabilitation therapists working in inpatient rehabilitation and acute-care units from September to November, 2020. Thirteen participants completed individual, semi-structured interviews focused on clinical practice and coping strategies. The analysis included a multi-step, inductive process. Four interconnecting factors chronicling participants' experiences emerged: sociopolitical, institutional, hospital unit, and personal. Stressors and buffers were noted that further shaped individual experiences. Utilization of an ecological framework provided a way to recognize the impact of a complex range of social and environmental factors affecting participants' experiences on personal and professional levels. Awareness of rehabilitation therapists' experiences enriches understanding of the pandemic's effect on healthcare workers and presents clinical implications for healthcare systems to promote therapist well-being

    Empowering stroke survivors beyond inpatient rehabilitation: the STRIDE program

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    Objective The timeframe from hospital discharge to the commencement of outpatient therapies represents a crucial yet often overlooked period in post-stroke recovery. We designed an eight-week post-stroke management program (STRIDE, Stroke Management Training and Inpatient Rehabilitation Discharge Education) targeting individuals discharging from an inpatient rehabilitation facility to home. The primary aims of this pilot study were to determine STRIDE feasibility and participant engagement. Methods Participants with first or recurrent stroke were enrolled. Each week, participants monitored and recorded their daily activity, completed a 15-min educational module and quiz, and partook in weekly and biweekly communication with a fellow participant and STRIDE coordinator, respectively. Feasibility was evaluated by successful initiation of STRIDE and enrollment of the target population. We also assessed participant adherence and conducted semi-structured exit interviews. Results Of the 99 individuals screened, 20 individuals were enrolled (7 females, 28.6 ± 15.7 days post-stroke). Several participants were unable to begin the program (n = 6) or complete the program (n = 4). Overall, participants completing at least 1 week of STRIDE (n = 14) demonstrated adherence with education module and quiz completion and communication with the STRIDE coordinator. Participant feedback from interviews was largely positive, underscoring the value of STRIDE during early post-stroke recovery. Conclusions These findings support the feasibility of an initiated multi-faceted stroke management program. Participant dropout was a limitation and serves as a consideration when designing future iterations of STRIDE. With the long-term goal of promoting autonomy and investment in one's continued recovery beyond the inpatient setting, STRIDE bridges the transition from hospital to home

    Empowering stroke survivors beyond inpatient rehabilitation: the STRIDE program

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    ObjectiveThe timeframe from hospital discharge to the commencement of outpatient therapies represents a crucial yet often overlooked period in post-stroke recovery. We designed an eight-week post-stroke management program (STRIDE, Stroke Management Training and Inpatient Rehabilitation Discharge Education) targeting individuals discharging from an inpatient rehabilitation facility to home. The primary aims of this pilot study were to determine STRIDE feasibility and participant engagement.MethodsParticipants with first or recurrent stroke were enrolled. Each week, participants monitored and recorded their daily activity, completed a 15-min educational module and quiz, and partook in weekly and biweekly communication with a fellow participant and STRIDE coordinator, respectively. Feasibility was evaluated by successful initiation of STRIDE and enrollment of the target population. We also assessed participant adherence and conducted semi-structured exit interviews.ResultsOf the 99 individuals screened, 20 individuals were enrolled (7 females, 28.6 ± 15.7 days post-stroke). Several participants were unable to begin the program (n = 6) or complete the program (n = 4). Overall, participants completing at least 1 week of STRIDE (n = 14) demonstrated adherence with education module and quiz completion and communication with the STRIDE coordinator. Participant feedback from interviews was largely positive, underscoring the value of STRIDE during early post-stroke recovery.ConclusionsThese findings support the feasibility of an initiated multi-faceted stroke management program. Participant dropout was a limitation and serves as a consideration when designing future iterations of STRIDE. With the long-term goal of promoting autonomy and investment in one's continued recovery beyond the inpatient setting, STRIDE bridges the transition from hospital to home

    What five decades of research tells us about the effects of youth psychological therapy: A multilevel meta-analysis and implications for science and practice

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    Across 5 decades, hundreds of randomized trials have tested psychological therapies for youth internalizing (anxiety, depression) and externalizing (misconduct, attention deficit and hyperactivity disorder) disorders and problems. Since the last broad-based youth metaanalysis in 1995, the number of trials has almost tripled and data-analytic methods have been refined. We applied these methods to the expanded study pool (447 studies; 30,431 youths), synthesizing 50 years of findings and identifying implications for research and practice. We assessed overall effect size (ES) and moderator effects using multilevel modeling to address ES dependency that is common, but typically not modeled, in meta-analyses. Mean posttreatment ES was 0.46; the probability that a youth in the treatment condition would fare better than a youth in the control condition was 63%. Effects varied according to multiple moderators, including the problem targeted in treatment: Mean ES at posttreatment was strongest for anxiety (0.61), weakest for depression (0.29), and nonsignificant for multiprob lem treatment (0.15). ESs differed across control conditions, with "usual care" emerging as a potent comparison condition, and across informants, highlighting the need to obtain and integrate multiple perspectives on outcome. Effects of therapy type varied by informant; only youth-focused behavioral therapies (including cognitive-behavioral therapy) showed similar and robust effects across youth, parent, and teacher reports. Effects did not differ for Caucasian versus minority samples, but more diverse samples are needed. The findings underscore the benefits of psychological treatments as well as the need for improved therapies and more representative, informative, and rigorous intervention science

    A global phylogeny of butterflies reveals their evolutionary history, ancestral hosts and biogeographic origins

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    Butterflies are a diverse and charismatic insect group that are thought to have evolved with plants and dispersed throughout the world in response to key geological events. However, these hypotheses have not been extensively tested because a comprehensive phylogenetic framework and datasets for butterfly larval hosts and global distributions are lacking. We sequenced 391 genes from nearly 2,300 butterfly species, sampled from 90 countries and 28 specimen collections, to reconstruct a new phylogenomic tree of butterflies representing 92% of all genera. Our phylogeny has strong support for nearly all nodes and demonstrates that at least 36 butterfly tribes require reclassification. Divergence time analyses imply an origin similar to 100 million years ago for butterflies and indicate that all but one family were present before the K/Pg extinction event. We aggregated larval host datasets and global distribution records and found that butterflies are likely to have first fed on Fabaceae and originated in what is now the Americas. Soon after the Cretaceous Thermal Maximum, butterflies crossed Beringia and diversified in the Palaeotropics. Our results also reveal that most butterfly species are specialists that feed on only one larval host plant family. However, generalist butterflies that consume two or more plant families usually feed on closely related plants
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