66 research outputs found

    Workshop on Autonomy for Future SMD Missions

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    Summary of the Workshop on Autonomy for Future SMD Missions that was held on July 21, 2017 at the 2017 NASA Exploration Science Forum (Moffett Field, CA)

    Planetary Rover Simulation for Lunar Exploration Missions

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    When planning planetary rover missions it is useful to develop intuition and skills driving in, quite literally, alien environments before incurring the cost of reaching said locales. Simulators make it possible to operate in environments that have the physical characteristics of target locations without the expense and overhead of extensive physical tests. To that end, NASA Ames and Open Robotics collaborated on a Lunar rover driving simulator based on the open source Gazebo simulation platform and leveraging ROS (Robotic Operating System) components. The simulator was integrated with research and mission software for rover driving, system monitoring, and science instrument simulation to constitute an end-to-end Lunar mission simulation capability. Although we expect our simulator to be applicable to arbitrary Lunar regions, we designed to a reference mission of prospecting in polar regions. The harsh lighting and low illumination angles at the Lunar poles combine with the unique reflectance properties of Lunar regolith to present a challenging visual environment for both human and computer perception. Our simulator placed an emphasis on high fidelity visual simulation in order to produce synthetic imagery suitable for evaluating human rover drivers with navigation tasks, as well as providing test data for computer vision software development.In this paper, we describe the software used to construct the simulated Lunar environment and the components of the driving simulation. Our synthetic terrain generation software artificially increases the resolution of Lunar digital elevation maps by fractal synthesis and inserts craters and rocks based on Lunar size-frequency distribution models. We describe the necessary enhancements to import large scale, high resolution terrains into Gazebo, as well as our approach to modeling the visual environment of the Lunar surface. An overview of the mission software system is provided, along with how ROS was used to emulate flight software components that had not been developed yet. Finally, we discuss the effect of using the high-fidelity synthetic Lunar images for visual odometry. We also characterize the wheel slip model, and find some inconsistencies in the produced wheel slip behaviour

    Therapy with mycophenolate mofetil for refractory acute and chronic GVHD.

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    We evaluated the pharmacokinetics and efficacy of oral mycophenolate mofetil (MMF) for treatment of refractory GVHD. In a prospective study of acute GVHD, 9 of 19 patients (47%) had a response and 10 (53%) had no improvement. Survival at 6 and 12 months after the start of MMF was 37 and 16%, respectively. In a retrospective study of acute GVHD, 14 of 29 patients (48%) had a response and 15 (52%) had no improvement. Survival at 6 and 12 months was 55 and 52%, respectively. In a prospective study of chronic GVHD, the cumulative incidence of disease resolution and withdrawal of all systemic immunosuppressive treatment was 9, 17 and 26% at 12, 24 and 36 months, respectively, after starting MMF. Thirteen patients (59%) required additional systemic immunosuppressive treatment for chronic GVHD. Nine of the 42 patients (21%) in the prospective studies discontinued MMF treatment because of toxicity. The area under the curve plasma concentrations of mycophenolic acid seemed to be suboptimal among patients with acute GVHD but not among those with chronic GVHD. MMF can be used effectively for treatment of GVHD.Bone Marrow Transplantation advance online publication, 20 April 2009; doi:10.1038/bmt.2009.76

    Psoralen and ultraviolet A irradiation (PUVA) as therapy for steroid-resistant cutaneous acute graft-versus-host disease

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    AbstractPsoralen plus ultraviolet A irradiation (PUVA) has immunomodulatory effects and is used to treat a variety of immune-mediated dermatologic diseases. We administered PUVA to 103 patients for treatment of steroid-resistant acute graft-versus-host disease (GVHD) of the skin. Twenty-nine patients had related donors (12 HLA-mismatched) and 74 had unrelated donors (23 HLA-mismatched). The median onset of GVHD was day 13 after transplantation, and the median onset of PUVA treatment was day 46. PUVA was administered as secondary therapy for 86 patients and tertiary therapy or greater for 17 patients. The median number of treatments was 16, and the mean cumulative exposure was 41 J/cm2. PUVA was generally well tolerated with 8 patients discontinuing therapy because of toxicity. At the start of PUVA treatment, 48 patients had rash affecting >50% of their body surface area (BSA), and 91 had rash involving >25% BSA. Of 65 patients who were evaluated after 6 weeks of PUVA treatment, 11 still had rash involving >50% BSA, 24 had rash involving >25% BSA, and 24 had no rash. The mean daily dose of prednisone at the start of PUVA therapy was 1.6 mg/kg compared to 0.7 mg/kg after 6 weeks of therapy. Fifty-nine patients (57%) did not require additional therapy for skin GVHD after starting PUVA. Ninety-two percent of patients developed chronic GVHD. Fifty-three patients (51%) remain alive at 129-1883 days after transplantation. These results suggest that PUVA can be an effective therapy for steroid-resistant acute GVHD of the skin.Biol Blood Marrow Transplant 2002;8(4):206-12

    The amphioxus genome and the evolution of the chordate karyotype

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    Lancelets ('amphioxus') are the modern survivors of an ancient chordate lineage, with a fossil record dating back to the Cambrian period. Here we describe the structure and gene content of the highly polymorphic approx520-megabase genome of the Florida lancelet Branchiostoma floridae, and analyse it in the context of chordate evolution. Whole-genome comparisons illuminate the murky relationships among the three chordate groups (tunicates, lancelets and vertebrates), and allow not only reconstruction of the gene complement of the last common chordate ancestor but also partial reconstruction of its genomic organization, as well as a description of two genome-wide duplications and subsequent reorganizations in the vertebrate lineage. These genome-scale events shaped the vertebrate genome and provided additional genetic variation for exploitation during vertebrate evolution

    Challenges of Rover Navigation at the Lunar Poles

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    Observations from Lunar Prospector, LCROSS, Lunar Reconnaissance Orbiter (LRO), and other missions have contributed evidence that water and other volatiles exist at the lunar poles in permanently shadowed regions. Combining a surface rover and a volatile prospecting and analysis payload would enable the detection and characterization of volatiles in terms of nature, abundance, and distribution. This knowledge could have impact on planetary science, in-situ resource utilization, and human exploration of space. While Lunar equatorial regions of the Moon have been explored by manned (Apollo) and robotic missions (Lunokhod, Cheng'e), no surface mission has reached the lunar poles

    Comparison of the benefits of cochlear implantation versus contra-lateral routing of signal hearing aids in adult patients with single-sided deafness: study protocol for a prospective within-subject longitudinal trial

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    Background Individuals with a unilateral severe-to-profound hearing loss, or single-sided deafness, report difficulty with listening in many everyday situations despite having access to well-preserved acoustic hearing in one ear. The standard of care for single-sided deafness available on the UK National Health Service is a contra-lateral routing of signals hearing aid which transfers sounds from the impaired ear to the non-impaired ear. This hearing aid has been found to improve speech understanding in noise when the signal-to-noise ratio is more favourable at the impaired ear than the non-impaired ear. However, the indiscriminate routing of signals to a single ear can have detrimental effects when interfering sounds are located on the side of the impaired ear. Recent published evidence has suggested that cochlear implantation in individuals with a single-sided deafness can restore access to the binaural cues which underpin the ability to localise sounds and segregate speech from other interfering sounds. Methods/Design The current trial was designed to assess the efficacy of cochlear implantation compared to a contra-lateral routing of signals hearing aid in restoring binaural hearing in adults with acquired single-sided deafness. Patients are assessed at baseline and after receiving a contra-lateral routing of signals hearing aid. A cochlear implant is then provided to those patients who do not receive sufficient benefit from the hearing aid. This within-subject longitudinal design reflects the expected care pathway should cochlear implantation be provided for single-sided deafness on the UK National Health Service. The primary endpoints are measures of binaural hearing at baseline, after provision of a contra-lateral routing of signals hearing aid, and after cochlear implantation. Binaural hearing is assessed in terms of the accuracy with which sounds are localised and speech is perceived in background noise. The trial is also designed to measure the impact of the interventions on hearing- and health-related quality of life. Discussion This multi-centre trial was designed to provide evidence for the efficacy of cochlear implantation compared to the contra-lateral routing of signals. A purpose-built sound presentation system and established measurement techniques will provide reliable and precise measures of binaural hearing. Trial registration Current Controlled Trials http://www.controlled-trials.com/ISRCTN33301739 (05/JUL/2013
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