190 research outputs found
Technology Development for the Advanced Technology Large Aperture Space Telescope (ATLAST) as a Candidate Large UV-Optical-Infrared (LUVOIR) Surveyor
The Advanced Technology Large Aperture Space Telescope (ATLAST) team has identified five key technologies to enable candidate architectures for the future large-aperture ultraviolet/optical/infrared (LUVOIR) space observatory envisioned by the NASA Astrophysics 30-year roadmap, Enduring Quests, Daring Visions. The science goals of ATLAST address a broad range of astrophysical questions from early galaxy and star formation to the processes that contributed to the formation of life on Earth, combining general astrophysics with direct-imaging and spectroscopy of habitable exoplanets. The key technologies are: internal coronagraphs, starshades (or external occulters), ultra-stable large-aperture telescopes, detectors, and mirror coatings. Selected technology performance goals include: 1x1010 raw contrast at an inner working angle of 35 milli-arcseconds, wavefront error stability on the order of 10 pm RMS per wavefront control step, autonomous on-board sensing & control, and zero-read-noise single-photon detectors spanning the exoplanet science bandpass between 400 nm and 1.8 m. Development of these technologies will provide significant advances over current and planned observatories in terms of sensitivity, angular resolution, stability, and high-contrast imaging. The science goals of ATLAST are presented and flowed down to top-level telescope and instrument performance requirements in the context of a reference architecture: a 10-meter-class, segmented aperture telescope operating at room temperature (~290 K) at the sun-Earth Lagrange-2 point. For each technology area, we define best estimates of required capabilities, current state-of-the-art performance, and current Technology Readiness Level (TRL) - thus identifying the current technology gap. We report on current, planned, or recommended efforts to develop each technology to TRL 5
A Future Large-Aperture UVOIR Space Observatory: Key Technologies and Capabilities
We present the key technologies and capabilities that will enable a future, large-aperture ultravioletopticalinfrared (UVOIR) space observatory. These include starlight suppression systems, vibration isolation and control systems, lightweight mirror segments, detector systems, and mirror coatings. These capabilities will provide major advances over current and near-future observatories for sensitivity, angular resolution, and starlight suppression. The goals adopted in our study for the starlight suppression system are 10-10 contrast with an inner working angle of 20 milliarcsec and broad bandpass. We estimate that a vibration and isolation control system that achieves a total system vibration isolation of 140 dB for a vibration-isolated mass of 5000 kg is required to achieve the high wavefront error stability needed for exoplanet coronagraphy. Technology challenges for lightweight mirror segments include diffraction-limited optical quality and high wavefront error stability as well as low cost, low mass, and rapid fabrication. Key challenges for the detector systems include visible-blind, high quantum efficiency UV arrays, photon counting visible and NIR arrays for coronagraphic spectroscopy and starlight wavefront sensing and control, and detectors with deep full wells with low persistence and radiation tolerance to enable transit imaging and spectroscopy at all wavelengths. Finally, mirror coatings with high reflectivity ( 90), high uniformity ( 1) and low polarization ( 1) that are scalable to large diameter mirror substrates will be essential for ensuring that both high throughput UV observations and high contrast observations can be performed by the same observatory
Agreement Between Older Persons and Their Surrogate Decision‐Makers Regarding Participation in Advance Care Planning
Objectives: To examine agreement between older persons and their surrogates regarding participation in advance care planning (ACP).
Design: Observational cohort study.
Setting: Community.
Participants: Persons aged 65 and older and the individual they identified as most likely to make treatment decisions on their behalf.
Measurements: Older persons were asked about participation in four activities: completion of living will, completion of healthcare proxy, communication regarding views about life‐sustaining treatment, and communication regarding views about quality versus quantity of life. Surrogates were asked whether they believed the older person had completed these activities.
Results: Of 216 pairs, 81% agreed about whether a living will had been completed (κ=0.61, 95% confidence interval (CI) 0.51–0.72). Only 68% of pairs agreed about whether a healthcare proxy had been completed (κ=0.39, 95% CI 0.29–0.50), 64% agreed about whether they had communicated regarding life‐sustaining treatment (κ=0.22, 95% CI 0.09–0.35), and 62% agreed about whether they had communicated regarding quality versus quantity of life (κ=0.23, 95% CI 0.11–0.35).
Conclusion: Although agreement between older persons and their surrogates regarding living will completion was good, agreement about participation in other aspects of ACP was fair to poor. Additional study is necessary to determine who is providing the most accurate report of objective ACP components and whether agreement regarding participation in ACP is associated with greater shared understanding of patient preferences
Using the Pathways Community HUB Care Coordination Model to Address Chronic Illnesses: A Case Study
Background/Objectives: Ohio communities are developing and expanding care coordination initiatives to integrate care for low-income pregnant women. Some of these initiatives are guided by the Pathways Community HUB model, which uses community healthworkers to address health, social, and behavioral risks for at-risk populations. This study documents the development, challenges andmanagement responses, and lessons learned from implementing a Pathways Community HUB care coordination program for anotherpopulation -- low-income adults with chronic disease risks.Methods: The study utilizes data extracted from the Care Coordination Systems (CCS) database used in Lucas County, Ohio between2015 and 2017 and interviews with program managers. Based on CCS data and insights from those interviewed, we describe the development and accomplishments of a Pathways Community HUB program for adults with chronic illnesses and identify challenges and lessons learned.Results: The Toledo/Lucas County program addressed more than half of 3,515 identified health and behavioral risks for 651 low-income adults in the program during its first two years of operation. Key challenges included building community support, establishing capacities to coordinate care, and sustaining the program over time. Establishing community networks to support program services and developing multiple funding sources are key lessons for long-term program sustainability.Conclusions: Documenting challenges and successes of existing programs and extracting lessons to guide implementation of similarpublic health efforts can potentially improve delivery of interventions. The Pathways Community HUB model has demonstrated success in addressing risks among at-risk adults. However, more comprehensive assessments of the model across different populations are warranted
Promoting advance care planning as health behavior change: Development of scales to assess Decisional Balance, Medical and Religious Beliefs, and Processes of Change
Objective: To develop measures representing key constructs of the Transtheoretical Model (TTM) of behavior change as applied to advance care planning (ACP) and to examine whether associations between these measures replicate the relationships posited by the TTM.
Methods: Sequential scale development techniques were used to develop measures for Decisional Balance (Pros and Cons of behavior change), ACP Values/Beliefs (religious beliefs and medical misconceptions serving as barriers to participation), Processes of Change (behavioral and cognitive processes used to foster participation) based on responses of 304 persons age ≥ 65 years.
Results: Items for each scale/subscale demonstrated high factor loading (\u3e.5) and good to excellent internal consistency (Cronbach α .76–.93). Results of MANOVA examining scores on the Pros, Cons, ACP Values/Beliefs, and POC subscales by stage of change for each of the six behaviors were significant, Wilks’ λ = .555–.809, η2 = .068–.178, p ≤ .001 for all models.
Conclusion: Core constructs of the TTM as applied to ACP can be measured with high reliability and validity.
Practical implications: Cross-sectional relationships between these constructs and stage of behavior change support the use of TTM-tailored interventions to change perceptions of the Pros and Cons of participation in ACP and promote the use of certain Processes of Change in order to promote older persons’ engagement in ACP
Stages of Change for the Component Behaviors of Advance Care Planning
Objectives: To develop stages‐of‐change measures for advance care planning (ACP), conceptualized as a group of interrelated but separate behaviors, and to use these measures to characterize older persons\u27 engagement in and factors associated with readiness to participate in ACP.
Design: Observational cohort study.
Setting: Community.
Participants: Persons aged 65 and older recruited from physician offices and a senior center.
Measurements: Stages of change for six ACP behaviors: completion of a living will and healthcare proxy, communication with loved ones regarding use of life‐sustaining treatments and quantity versus quality of life, and communication with physicians about these same issues.
Results: Readiness to participate in ACP varied widely across behaviors. Whereas between approximately 50% and 60% of participants were in the action or maintenance stage for communicating with loved ones about life‐sustaining treatment and completing a living will, 40% were in the precontemplation stage for communicating with loved ones about quantity versus quality of life, and 70% and 75% were in the precontemplation stage for communicating with physicians. Participants were frequently in different stages for different behaviors. Few sociodemographic, health, or psychosocial factors were associated with stages of change for completing a living will, but a broader range of factors was associated with stages of change for communication with loved ones about quantity versus quality of life.
Conclusion: Older persons show a range of readiness to engage in different aspects of ACP. Individualized assessment and interventions targeted to stage of behavior change for each component of ACP may be an effective strategy to increase participation in ACP
Surface processes recorded by rocks and soils on Meridiani Planum, Mars: Microscopic Imager observations during Opportunity's first three extended missions
The Microscopic Imager (MI) on the Mars Exploration Rover Opportunity has returned images of Mars with higher resolution than any previous camera system, allowing detailed petrographic and sedimentological studies of the rocks and soils at the Meridiani Planum landing site. Designed to simulate a geologist's hand lens, the MI is mounted on Opportunity's instrument arm and can resolve objects 0.1 mm across or larger. This paper provides an overview of MI operations, data calibration, and analysis of MI data returned during the first 900 sols (Mars days) of the Opportunity landed mission. Analyses of Opportunity MI data have helped to resolve major questions about the origin of observed textures and features. These studies support eolian sediment transport, rather than impact surge processes, as the dominant depositional mechanism for Burns formation strata. MI stereo observations of a rock outcrop near the rim of Erebus Crater support the previous interpretation of similar sedimentary structures in Eagle Crater as being formed by surficial flow of liquid water. Well-sorted spherules dominate ripple surfaces on the Meridiani plains, and the size of spherules between ripples decreases by about 1 mm from north to south along Opportunity's traverse between Endurance and Erebus craters
Baseline transtheoretical and dietary behavioral predictors of dietary fat moderation over 12 and 24 months
Longitudinal predictors of dietary behavior change are important and in need of study. This secondary data analysis combined primary data across three randomized trials to examine transtheoretical model (TTM) and specific dietary predictors of successful dietary change at 12 and 24 months separately in treatment and control groups (N = 4178). The treatment group received three TTM-tailored print interventions over 12 months between 1995 and 2000. Chi-square and MANOVA analyses were used to examine baseline predictors of dietary outcome at 12 and 24 months. Last, a multivariable logistic regression was conducted with all baseline variables included. Across all analyses in both treatment and control groups, the most robust predictors of successful change were for TTM-tailored treatment group, preparation stage of change, and increased use of dietary behavior variables such as moderating fat intake, substitution of lower fat foods, and increasing intake of healthful foods. These results provide strong evidence for treatment, stage and behavioral dietary severity effects predicting dietary behavior change over time, and for targeting these variables with the strongest relationships to outcome in interventions, such as TTM-tailored dietary interventions
Common Factors Predicting Long-term Changes in Multiple Health Behaviors
This study was designed to assess if there are consistent treatment, stage, severity, effort and demographic effects which predict long-term changes across the multiple behaviors of smoking, diet and sun exposure. A secondary data analysis integrated data from four studies on smoking cessation (N = 3927), three studies on diet (N = 4824) and four studies on sun exposure (N = 6465). Across all three behaviors, behavior change at 24 months was related to treatment, stage of change, problem severity and effort effects measured at baseline. There were no consistent demographic effects. Across multiple behaviors, long-term behavior changes are consistently related to four effects that are dynamic and open to change. Behavior changes were not consistently related to static demographic variables. Future intervention research can target the four effects to determine if breakthroughs can be produced in changing single and multiple behaviors
Developmental Cryogenic Active Telescope Testbed, a Wavefront Sensing and Control Testbed for the Next Generation Space Telescope
As part of the technology validation strategy of the next generation space telescope (NGST), a system testbed is being developed at GSFC, in partnership with JPL and Marshall Space Flight Center (MSFC), which will include all of the component functions envisioned in an NGST active optical system. The system will include an actively controlled, segmented primary mirror, actively controlled secondary, deformable, and fast steering mirrors, wavefront sensing optics, wavefront control algorithms, a telescope simulator module, and an interferometric wavefront sensor for use in comparing final obtained wavefronts from different tests. The developmental. cryogenic active telescope testbed (DCATT) will be implemented in three phases. Phase 1 will focus on operating the testbed at ambient temperature. During Phase 2, a cryocapable segmented telescope will be developed and cooled to cryogenic temperature to investigate the impact on the ability to correct the wavefront and stabilize the image. In Phase 3, it is planned to incorporate industry developed flight-like components, such as figure controlled mirror segments, cryogenic, low hold power actuators, or different wavefront sensing and control hardware or software. A very important element of the program is the development and subsequent validation of the integrated multidisciplinary models. The Phase 1 testbed objectives, plans, configuration, and design will be discussed
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