269 research outputs found
The Sublime Triplets of Historical Consciousness
On the Future of History: The Postmodernist Challenge and Its Aftermath (Ernst Breisach) Stranded in the Present: Modern Time and the Melancholy of History (Peter Fritzsche) Déjà vu: Aberrations of Cultural Memory (Peter Krapp) History in Transit: Experience, Identity, Critical Theory (Dominick LaCapra) Lethe: The Art and Critique of Forgetting (Harald Weinrich
Cryogenic Propellant Storage and Transfer Technology Demonstration: Advancing Technologies for Future Mission Architectures Beyond Low Earth Orbit
As part of U.S. National Space Policy, NASA is seeking an innovative path for human space exploration, which strengthens the capability to extend human and robotic presence throughout the solar system. NASA is laying the groundwork to enable humans to safely reach multiple potential destinations, including the Moon, asteroids, Lagrange points, and Mars and its environs. In support of this, NASA is embarking on the Technology Demonstration Mission Cryogenic Propellant Storage and Transfer (TDM CPST) Project to test and validate key cryogenic capabilities and technologies required for future exploration elements, opening up the architecture for large cryogenic propulsion stages and propellant depots. The TDM CPST will provide an on-orbit demonstration of the capability to store, transfer, and measure cryogenic propellants for a duration that enables long term human space exploration missions beyond low Earth orbit. This paper will present a summary of the cryogenic fluid management technology maturation effort, infusion of those technologies into flight hardware development, and a summary of the CPST preliminary design
Association Between Chronic Hepatitis C Virus Infection and Myocardial Infarction Among People Living With HIV in the United States.
Hepatitis C virus (HCV) infection is common among people living with human immunodeficiency virus (PLWH). Extrahepatic manifestations of HCV, including myocardial infarction (MI), are a topic of active research. MI is classified into types, predominantly atheroembolic type 1 MI (T1MI) and supply-demand mismatch type 2 MI (T2MI). We examined the association between HCV and MI among patients in the Centers for AIDS Research (CFAR) Network of Integrated Clinical Systems, a US multicenter clinical cohort of PLWH. MIs were centrally adjudicated and categorized by type using the Third Universal Definition of Myocardial Infarction. We estimated the association between chronic HCV (RNA+) and time to MI while adjusting for demographic characteristics, cardiovascular risk factors, clinical characteristics, and history of injecting drug use. Among 23,407 PLWH aged ≥18 years, there were 336 T1MIs and 330 T2MIs during a median of 4.7 years of follow-up between 1998 and 2016. HCV was associated with a 46% greater risk of T2MI (adjusted hazard ratio (aHR) = 1.46, 95% confidence interval (CI): 1.09, 1.97) but not T1MI (aHR = 0.87, 95% CI: 0.58, 1.29). In an exploratory cause-specific analysis of T2MI, HCV was associated with a 2-fold greater risk of T2MI attributed to sepsis (aHR = 2.01, 95% CI: 1.25, 3.24). Extrahepatic manifestations of HCV in this high-risk population are an important area for continued research
Integrating gerontology competencies into graduate nursing programs.
Current demographic and health care utilization trends strongly indicate a rapidly increasing demand for nurses who are well qualified to care for older adults. Advanced practice nurses are positioned to assume leadership roles in geriatric nursing care; however, they must first acquire adequate preparatory education. This article describes two graduate nursing schools’ curricular innovations that were funded by The John A. Hartford Foundation, in collaboration with the American Association of Colleges of Nursing (AACN), through the Geriatric Nursing Education Project: Enhancing Gerontological/Geriatric Nursing for Advanced Practice Nursing. These programs at University of North Carolina at Greensboro and Pennsylvania State University incorporated techniques to translate the Nurse Practitioner and Clinical Nurse Specialist Competencies for Older Adult Care [American Association of Colleges of Nursing. (2004). Nurse practitioner and clinical nurse specialist competencies for older adult care. Washington, DC: AACN] into an advanced practice curriculum and developed strategies to sustain curricular innovations. Finally, lessons learned from these two projects are discussed and recommendations are made for integrating geriatric nursing competencies into graduate programs
Analysis of the 24-Hour Activity Cycle: An illustration examining the association with cognitive function in the Adult Changes in Thought (ACT) Study
The 24-hour activity cycle (24HAC) is a new paradigm for studying activity
behaviors in relation to health outcomes. This approach captures the
interrelatedness of the daily time spent in physical activity (PA), sedentary
behavior (SB), and sleep. We illustrate and compare the use of three popular
approaches, namely isotemporal substitution model (ISM), compositional data
analysis (CoDA), and latent profile analysis (LPA) for modeling outcome
associations with the 24HAC. We apply these approaches to assess an association
with a cognitive outcome, measured by CASI item response theory (IRT) score, in
a cohort of 1034 older adults (mean [range] age = 77 [65-100]; 55.8% female;
90% White) who were part of the Adult Changes in Thought (ACT) Activity
Monitoring (ACT-AM) sub-study. PA and SB were assessed with thigh-worn activPAL
accelerometers for 7 days. We highlight differences in assumptions between the
three approaches, discuss statistical challenges, and provide guidance on
interpretation and selecting an appropriate approach. ISM is easiest to apply
and interpret; however, the typical ISM model assumes a linear association.
CoDA specifies a non-linear association through isometric logratio
transformations that are more challenging to apply and interpret. LPA can
classify individuals into groups with similar time-use patterns. Inference on
associations of latent profiles with health outcomes need to account for the
uncertainty of the LPA classifications which is often ignored. The selection of
the most appropriate method should be guided by the scientific questions of
interest and the applicability of each model's assumptions. The analytic
results did not suggest that less time spent on SB and more in PA was
associated with better cognitive function. Further research is needed into the
health implications of the distinct 24HAC patterns identified in this cohort.Comment: 51 pages, 11 tables, 8 figure
Front Psychol
The 24-h activity cycle (24HAC) is a new paradigm for studying activity behaviors in relation to health outcomes. This approach inherently captures the interrelatedness of the daily time spent in physical activity (PA), sedentary behavior (SB), and sleep. We describe three popular approaches for modeling outcome associations with the 24HAC exposure. We apply these approaches to assess an association with a cognitive outcome in a cohort of older adults, discuss statistical challenges, and provide guidance on interpretation and selecting an appropriate approach. We compare the use of the isotemporal substitution model (ISM), compositional data analysis (CoDA), and latent profile analysis (LPA) to analyze 24HAC. We illustrate each method by exploring cross-sectional associations with cognition in 1,034 older adults (Mean age = 77; Age range = 65-100; 55.8% female; 90% White) who were part of the Adult Changes in Thought (ACT) Activity Monitoring (ACT-AM) sub-study. PA and SB were assessed with thigh-worn activPAL accelerometers for 7-days. For each method, we fit a multivariable regression model to examine the cross-sectional association between the 24HAC and Cognitive Abilities Screening Instrument item response theory (CASI-IRT) score, adjusting for baseline characteristics. We highlight differences in assumptions and the scientific questions addressable by each approach. ISM is easiest to apply and interpret; however, the typical ISM assumes a linear association. CoDA uses an isometric log-ratio transformation to directly model the compositional exposure but can be more challenging to apply and interpret. LPA can serve as an exploratory analysis tool to classify individuals into groups with similar time-use patterns. Inference on associations of latent profiles with health outcomes need to account for the uncertainty of the LPA classifications, which is often ignored. Analyses using the three methods did not suggest that less time spent on SB and more in PA was associated with better cognitive function. The three standard analytical approaches for 24HAC each have advantages and limitations, and selection of the most appropriate method should be guided by the scientific questions of interest and applicability of each model's assumptions. Further research is needed into the health implications of the distinct 24HAC patterns identified in this cohort
Water quality guidelines for chemicals: learning lessons to deliver meaningful environmental metrics
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