245 research outputs found

    Flight Operations of Two Rapidly Assembled CubeSats with Commercial Infrared Cameras: The Rogue-Alpha,Beta Program

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    The Aerospace Corporation’s Rogue-alpha, betaprogram, co-funded by the Space and Missile Systems Center’s Development Corps, is a rapid prototyping effort that built and launched two 3-Unit CubeSats equipped with modified commercial IR camera payloads, laser communications and precision pointing capabilities in 18-months. Launched on 2 November 2019, the two spacecraft were released from the ISS Cygnus NG-12 robotic resupply spacecraft on 31 January 2020 into a circular 460-km, 52° inclined orbit. The two Rogue spacecraft are serving as testbeds for studying wide-field-of-view fast-framing imaging, on-orbit stellar calibration techniques for small IR payloads, and associated spacecraft flight operations. Precision pointing is enabled by three star sensors. High data rate sensor observations are enabled by the ultra-compact 200 Mbps lasercom system, which downlinks gigabytes of stored data during a single laser contact, using The Aerospace Corporation’s prototype ground stations located in El Segundo, California. The Rogue-alpha, beta IR sensor is a 1.4 micron band, 640x512 pixel, 28° field of view, InGaAs SWIR camera. It is accompanied by a panchromatic, 10-megapixel, 37° field of view visible context camera. Modes of sensor operation have included: 1) horizon-pointed imaging in all directions relative to the spacecraft orbit (fore, aft, port, and starboard) which is designed to maximize the imaged field of view, 2) point-and-stare imaging, 3) nadir-pointed, and 4) stereo fore-aft pointing using both spacecraft. All of these modes of operation are usually conducted in multi-frame collections at 1-20hz for dozens to thousands of frames. Highlights from the Rogue-alpha, beta sensor Earth remote sensing observation experiments will be presented. These have included impressive video imagery of hurricanes, typhoons, thunderstorms, and high clouds in the intra-tropical convergence zone. Infrared and visible point sources studied include gas flares, wildfires, active volcanos, nighttime lights, and other phenomena, including the first infrared CubeSat observations of space launch upper stages in flight. Stereo cloud imaging observations were also conducted with an aim of better understanding Earth backgrounds from low Earth orbit. Highlights from the CubeSat flight operations experiments include: 1) spacecraft-to-spacecraft boresight alignment of Rogue’s lasercom systems, and 2) metric and radiometric calibration of Rogue’s flight cameras using bright infrared stars. The results from the Rogue-alpha, beta460-km orbit show the exciting possibilities for wide-field-of-view missions from low earth orbit

    Imaging of atmospheric gravity waves in the stratosphere and upper mesosphere using satellite and ground-based observations over Australia during the TWPICE campaign

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    Extent: 20p.During the Tropical Warm Pool International Cloud Experiment (TWPICE) an intense tropical low was situated between Darwin and Alice Springs, Australia. Observations made on 31 January 2006 by the Atmospheric Infrared Sounder instrument on the NASA Aqua satellite imaged the presence of atmospheric gravity waves (AGWs), at approximately 40 km altitude, with horizontal wavelengths between 200 and 400 km that were originating from the region of the storm. Airglow images obtained from Alice Springs (about 600 km from the center of the low) showed the presence of similar waves with observed periods of 1 to 2 h. The images also revealed the presence of 30- to 45-km-horizontal-wavelength AGWs with shorter observed periods of near 15 to 25 min. Ray tracing calculations show that (1) some of the long wavelength waves traveled on rays, without ducting, to the altitudes where the observations were obtained, and (2) shorter-period waves rapidly reached 85 km altitude at a horizontal distance close to the storm, thus occurring over Alice Springs only if they were trapped or ducted. The mesospheric inversion layer seen in the measured temperature data almost forms such a trapped region. The winds therefore critically control the formation of the trapped region. Wind profiles deduced from the available data show the plausibility for the formation of such a trapped region. Variations in the wind, however, would make ideal trapped region conditions short-lived, and this may account for the sporadic nature of the short-period wave observations.J. H. Hecht, M. J. Alexander, R. L. Walterscheid, L. J. Gelinas, R. A. Vincent, A. D. MacKinnon, J. M. Woithe, P. T. May, W. R. Skinner, M. G. Mlynczak, and J. M. Russell II

    Widespread Site-Dependent Buffering of Human Regulatory Polymorphism

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    The average individual is expected to harbor thousands of variants within non-coding genomic regions involved in gene regulation. However, it is currently not possible to interpret reliably the functional consequences of genetic variation within any given transcription factor recognition sequence. To address this, we comprehensively analyzed heritable genome-wide binding patterns of a major sequence-specific regulator (CTCF) in relation to genetic variability in binding site sequences across a multi-generational pedigree. We localized and quantified CTCF occupancy by ChIP-seq in 12 related and unrelated individuals spanning three generations, followed by comprehensive targeted resequencing of the entire CTCF–binding landscape across all individuals. We identified hundreds of variants with reproducible quantitative effects on CTCF occupancy (both positive and negative). While these effects paralleled protein–DNA recognition energetics when averaged, they were extensively buffered by striking local context dependencies. In the significant majority of cases buffering was complete, resulting in silent variants spanning every position within the DNA recognition interface irrespective of level of binding energy or evolutionary constraint. The prevalence of complex partial or complete buffering effects severely constrained the ability to predict reliably the impact of variation within any given binding site instance. Surprisingly, 40% of variants that increased CTCF occupancy occurred at positions of human–chimp divergence, challenging the expectation that the vast majority of functional regulatory variants should be deleterious. Our results suggest that, even in the presence of “perfect” genetic information afforded by resequencing and parallel studies in multiple related individuals, genomic site-specific prediction of the consequences of individual variation in regulatory DNA will require systematic coupling with empirical functional genomic measurements

    Evidence of accelerated ageing in clinical drug addiction from immune, hepatic and metabolic biomarkers

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    Background: Drug addiction is associated with significant disease and death, but its impact on the ageing process has not been considered. The recent demonstration that many of the items available in routine clinical pathology have applicability as biomarkers of the ageing process implies that routine clinical laboratory parameters would be useful as an initial investigation of this possibility. Methods: 12,093 clinical laboratory results 1995-2006 were reviewed. To make the age ranges of the medical and addicted groups comparable the age range was restricted to 15-45 years. Results: 739 drug addicted (DA) and 5834 general medical (GM) age matched blood samples were compared. Significant elevation of immune parameters was noted in the C-reactive protein, erythrocyte sedimentation rate, total lymphocyte count, serum globulins and the globulin:albumin ratio (P < 0.01). Alanine aminotranferase, creatinine, urea, and insulin like growth factor-1 were also significantly higher (P < 0.01) in the DA group. Albumin, body mass index and dihydroepiandrosterone sulphate were unchanged and cholesterol was lower (all P < 0.05). Conclusion: These data demonstrate for the first time that addiction is associated with an altered profile of common biomarkers of ageing raising the possibility that the ageing process may be altered in this group. Infective and immune processes may be centrally involved. They suggest that addiction forms an interesting model to further examine the contribution of immune suppression and hyperstimulation to the ageing process

    Cerebellar Asymmetry and Cortical Connectivity in Monozygotic Twins with Discordant Handedness

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    Handedness differentiates patterns of neural asymmetry and interhemispheric connectivity in cortical systems that underpin manual and language functions. Contemporary models of cerebellar function incorporate complex motor behaviour and higher-order cognition, expanding upon earlier, traditional associations between the cerebellum and motor control. Structural MRI defined cerebellar volume asymmetries and correlations with corpus callosum (CC) size were compared in 19 pairs of adult female monozygotic twins strongly discordant for handedness (MZHd). Volume and asymmetry of cerebellar lobules were obtained using automated parcellation.CC area and regional widths were obtained from midsagittal planimetric measurements. Within the cerebellum and CC, neurofunctional distinctions were drawn between motor and higher-order cognitive systems. Relationships amongst regional cerebellar asymmetry and cortical connectivity (as indicated by CC widths) were investigated. Interactions between hemisphere and handedness in the anterior cerebellum were due to a larger right-greater-than-left hemispheric asymmetry in right-handed (RH) compared to left-handed (LH) twins. In LH twins only, anterior cerebellar lobule volumes (IV, V) for motor control were associated with CC size, particularly in callosal regions associated with motor cortex connectivity. Superior posterior cerebellar lobule volumes (VI, Crus I, Crus II, VIIb) showed no correlation with CC size in either handedness group. These novel results reflected distinct patterns of cerebellar-cortical relationships delineated by specific CC regions and an anterior-posterior cerebellar topographical mapping. Hence, anterior cerebellar asymmetry may contribute to the greater degree of bilateral cortical organisation of frontal motor function in LH individuals
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