1,869 research outputs found

    A Glimpse from the Inside of a Space Suit: What Is It Really Like to Train for an EVA?

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    The beauty of the view from the office of a spacewalking astronaut gives the impression of simplicity, but few beyond the astronauts, and those who train them, know what it really takes to get there. Extravehicular Activity (EVA) training is an intense process that utilizes NASA's Neutral Buoyancy Laboratory (NBL) to develop a very specific skill set needed to safely construct and maintain the orbiting International Space Station. To qualify for flight assignments, astronauts must demonstrate the ability to work safely and efficiently in the physically demanding environment of the spacesuit, possess an acute ability to resolve unforeseen problems, and implement proper tool protocols to ensure no tools will be lost in space. Through the insights and the lessons learned by actual EVA astronauts and EVA instructors, this paper twill take you on a journey through an astronaut's earliest experiences working in the spacesuit. termed the Extravehicular Mobility Unit (EMU), in the underwater training environment of the NBL. This work details an actual Suit Qualification NBL training event, outlines the numerous challenges the astronauts face throughout their initial training, and the various ways they adapt their own abilities to overcome them. The goal of this paper is to give everyone a small glimpse into what it is really like to work in a spacesuit

    21st Century Extravehicular Activities: Synergizing Past and Present Training Methods for Future Spacewalking Success

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    Neil Armstrong's understated words, "That's one small step for man, one giant leap for mankind." were spoken from Tranquility Base forty years ago. Even today, those words resonate in the ears of millions, including many who had yet to be born when man first landed on the surface of the moon. By their very nature, and in the the spirit of exploration, extravehicular activities (EVAs) have generated much excitement throughout the history of manned spaceflight. From Ed White's first space walk in June of 1965, to the first steps on the moon in 1969, to the expected completion of the International Space Station (ISS), the ability to exist, live and work in the vacuum of space has stood as a beacon of what is possible. It was NASA's first spacewalk that taught engineers on the ground the valuable lesson that successful spacewalking requires a unique set of learned skills. That lesson sparked extensive efforts to develop and define the training requirements necessary to ensure success. As focus shifted from orbital activities to lunar surface activities, the required skill-set and subsequently the training methods, changed. The requirements duly changed again when NASA left the moon for the last time in 1972 and have continued to evolve through the Skylab, Space Shuttle; and ISS eras. Yet because the visits to the moon were so long ago, NASA's expertise in the realm of extra-terrestrial EVAs has diminished. As manned spaceflight again shifts its focus beyond low earth orbit, EVA success will depend on the ability to synergize the knowledge gained over 40+ years of spacewalking to create a training method that allows a single crewmember to perform equally well, whether performing an EVA on the surface of the Moon, while in the vacuum of space, or heading for a rendezvous with Mars. This paper reviews NASA's past and present EVA training methods and extrapolates techniques from both to construct the basis for future EVA astronaut training

    Maternal plasma lipid levels across pregnancy and the risks of small-for-gestational age and low birth weight: a cohort study from rural Gambia.

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    BACKGROUND: Sub-optimal maternal lipid levels during pregnancy may be implicated in the pathophysiological mechanisms leading to low birth weight (LBW) and small-for-gestational-age (SGA). We aimed to determine whether maternal lipid levels across pregnancy were associated with birth weight and the risks of LBW and SGA in rural Gambia. METHODS: This secondary analysis of the ENID trial involved 573 pregnant women with term deliveries. Plasma levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), and triglycerides (TG) were analyzed at enrolment (mean (SD) = 13.9 (3.3) weeks gestation), 20 and 30 weeks gestation as continuous variables and percentile groups. Regression models with adjustment for confounders were used to examine associations between gestational lipid levels and birth weight and the risks of LBW (birth weight 90th percentile) LDL-c at 30 weeks gestation was associated with a 55% lower risk of SGA compared with referent LDL-c (P = 0.017). Increased levels of TC (β = 1.3, P = 0.027) at 20 weeks gestation and of TC (β = 1.2, P = 0.006) and LDL-c (β = 1.5, P = 0.002) at 30 weeks gestation were all associated with higher birth weight. CONCLUSIONS: In rural Gambia, lipid levels during pregnancy were associated with infant birth weight and the risks of LBW and SGA. Associations varied by lipid class and changed across pregnancy, indicating an adaptive process by which maternal lipids may influence fetal growth and birth outcomes. TRIAL REGISTRATION: This trial was registered as ISRCTN49285450 on: 12/11/2009

    Resistance, Extinction and Everything in Between - The Diverse Responses of Seaweeds to Marine Heatwaves

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    Globally, anomalously warm temperature events have increased by 34% in frequency and 17% in duration from 1925 to 2016 with potentially major impacts on coastal ecosystems. These “marine heatwaves” (MHWs) have been linked to changes in primary productivity, community composition and biogeography of seaweeds, which often control ecosystem function and services. Here we journalarticle the literature on seaweed responses to MHWs, including 58 observations related to resistance, bleaching, changes in abundance, species invasions and local to regional extinctions. More records existed for canopy-forming kelps and bladed and filamentous turf-forming seaweeds than for canopy-forming fucoids, geniculate coralline turf and crustose coralline algae. Turf-forming seaweeds, especially invasive seaweeds, generally increased in abundance after a MHW, whereas native canopy-forming kelps and fucoids typically declined in abundance. We also found four examples of regional extinctions of kelp and fucoids following specific MHWs, events that likely have long term consequences for ecological structure and functioning. Although a relatively small number of studies have described impacts of MHWs on seaweed, the broad range of documented responses highlights the necessity of better baseline information regarding seaweed distributions and performance, and the need to study specific characteristics of MHWs that affect the vulnerability and resilience of seaweeds to these increasingly important climatic perturbations. A major challenge will be to disentangle impacts caused by the extreme temperature increases of MHWs itself from co-occurring potential stressors including altered current patterns, increasing herbivory, changes in water clarity and nutrient content, solar radiation and desiccation stress in the intertidal zone. With future increases anticipated in the intensity, duration and frequencies of MHWs, we expect to see more replacements of large long-lived habitat forming seaweeds with smaller ephemeral seaweeds, reducing the habitat structure and effective services seaweed-dominated reefs can provide

    Transcriptional upregulation of c-MET is associated with invasion and tumor budding in colorectal cancer

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    c-MET and its ligand HGF are frequently overexpressed in colorectal cancer (CRC) and increased c-MET levels are found in CRC liver metastases. This study investigated the role of the HGF/c-MET axis in regulating migration/invasion in CRC, using pre-clinical models and clinical samples. Pre-clinically, we found marked upregulation of c-MET at both protein and mRNA levels in several invasive CRC cells. Down-regulation of c-MET using RNAi suppressed migration/invasion of parental and invasive CRC cells. Stimulation of CRC cells with rh-HGF or co-culture with HGF-expressing colonic myofibroblasts, resulted in significant increases in their migratory/invasive capacity. Importantly, HGF-induced c-MET activation promoted rapid downregulation of c-MET protein levels, while the MET transcript remained unaltered. Using RNA in situ hybridization (RNA ISH), we further showed that MET mRNA, but not protein levels, were significantly upregulated in tumor budding foci at the invasive front of a cohort of stage III CRC tumors (p < 0.001). Taken together, we show for the first time that transcriptional upregulation of MET is a key molecular event associated with CRC invasion and tumor budding. This data also indicates that RNA ISH, but not immunohistochemistry, provides a robust methodology to assess MET levels as a potential driving force of CRC tumor invasion and metastasis

    Bridging Research, Practice, and Policy: The “Evidence Academy” Conference Model

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    Innovative models to facilitate more rapid uptake of research findings into practice are urgently needed. Community members who engage in research can accelerate this process by acting as adoption agents. We implemented an Evidence Academy conference model bringing together researchers, health professionals, advocates, and policy makers across North Carolina to discuss high-impact, life-saving study results. The overall goal is to develop dissemination and implementation strategies for translating evidence into practice and policy. Each one-day, single-theme, regional meeting focuses on a leading community-identified health priority. The model capitalizes on the power of diverse local networks to encourage broad, common awareness of new research findings. Furthermore, it emphasizes critical reflection and active group discussion on how to incorporate new evidence within and across organizations, health care systems, and communities. During the concluding session, participants are asked to articulate action plans relevant to their individual interests, work setting, or area of expertise

    \u27I need time to start antiretroviral therapy\u27: Understanding reasons for delayed ART initiation among people diagnosed with HIV in Lusaka, Zambia

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    INTRODUCTION: Rapid antiretroviral therapy (ART) initiation can improve patient outcomes such as viral suppression and prevent new infections. However, not everyone who can start ART does so immediately. METHODS: We conducted a qualitative study to inform interventions supporting rapid initiation in the \u27Test and Start\u27 era. We purposively sampled 20 adult patients living with HIV and a previous gap in care from ten health facilities in Lusaka, Zambia for interviews. We inductively analysed transcripts using a thematic, narrative approach. In their narratives, seven participants discussed delaying ART initiation. RESULTS: Drawing on messages gleaned from facility-based counselling and community information, many cited greater fear of rapid sickness or death due to imperfect adherence or treatment side effects than negative health consequences due to delayed initiation. Participants described needing time to \u27prepare\u27 their minds for a lifetime treatment commitment. Concerns about inadvertent HIV status disclosure during drug collection discouraged immediate initiation, as did feeling healthy, and worries about the impact of ART initiation on relationship dynamics. CONCLUSION: Findings suggest that counselling messages should accurately communicate treatment risks, without perpetuating fear-based narratives about HIV. Identifying and managing patient-specific concerns and reasons for the \u27need for time\u27 may be important for supporting individuals to rapidly accept lifelong treatment.Key messagesFear-based adherence messaging in health facilities about the dangers of missing a treatment dose or changing the time when ART is taken contributes to Zambian patients\u27 refusals of immediate ART initiationResponsive health systems that balance a stated need for time to accept one\u27s diagnosis and prepare to embark on a lifelong treatment plan with interventions to identify and manage patient-specific treatment related fears and concerns may support more rapid ART initiationPerceived social stigma around HIV continues to be a significant challenge for treatment initiation

    Primary care-based intervention to reduce at-risk drinking in older adults: a randomized controlled trial

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    To examine whether a multi-faceted intervention among older at-risk drinking primary care patients reduced at-risk drinking and alcohol consumption at 3 and 12 months.Randomized controlled trial.Three primary care sites in southern California.Six hundred and thirty-one adults aged ≥ 55 years who were at-risk drinkers identified by the Comorbidity Alcohol Risk Evaluation Tool (CARET) were assigned randomly between October 2004 and April 2007 during an office visit to receive a booklet on healthy behaviors or an intervention including a personalized report, booklet on alcohol and aging, drinking diary, advice from the primary care provider and telephone counseling from a health educator at 2, 4 and 8 weeks.The primary outcome was the proportion of participants meeting at-risk criteria, and secondary outcomes were number of drinks in past 7 days, heavy drinking (four or more drinks in a day) in the past 7 days and risk score.At 3 months, relative to controls, fewer intervention group participants were at-risk drinkers [odds ratio (OR) 0.41; 95% confidence interval (CI) 0.22–0.75]; they reported drinking fewer drinks in the past 7 days [rate ratio (RR) 0.79; 95% CI 0.70–0.90], less heavy drinking (OR 0.46; 95% CI 0.22–0.99) and had lower risk scores (RR 0.77 95% CI 0.63–0.94). At 12 months, only the difference in number of drinks remained statistically significant (RR 0.87; 95% CI 0.76–0.99).A multi-faceted intervention among older at-risk drinkers in primary care does not reduce the proportions of at-risk or heavy drinkers, but does reduce amount of drinking at 12 months.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79363/1/j.1360-0443.2010.03229.x.pd

    A global assessment of marine heatwaves and their drivers

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    Marine heatwaves (MHWs) can cause devastating impacts to marine life. Despite the serious consequences of MHWs, our understanding of their drivers is largely based on isolated case studies rather than any systematic unifying assessment. Here we provide the first global assessment under a consistent framework by combining a confidence assessment of the historical refereed literature from 1950 to February 2016, together with the analysis of MHWs determined from daily satellite sea surface temperatures from 1982–2016, to identify the important local processes, large-scale climate modes and teleconnections that are associated with MHWs regionally. Clear patterns emerge, including coherent relationships between enhanced or suppressed MHW occurrences with the dominant climate modes across most regions of the globe – an important exception being western boundary current regions where reports of MHW events are few and ocean-climate relationships are complex. These results provide a global baseline for future MHW process and prediction studies
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