51 research outputs found

    Relative Navigation, Microdischarge Plasma Thruster, and Distributed Communications Experiments on the FASTRAC Mission

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    Enabling technologies for nanosatellite formations will be demonstrated under the Formation Autonomy Spacecraft with Thrust, Relnav, Attitude, and Crosslink (FASTRAC) program. Two °ight-ready nanosatellites will be designed, fabricated, integrated, and tested during the two year design period. Three speci¯c new and innovative technologies which will be demonstrated during the mission are Relative Navigation, Plasma Microthrusters, and Distributed Communications. A sensor set consisting of Global Positioning System (GPS) receiver, magnetometer, and MEMS Inertial Measurement Unit (IMU) will be used to determine position and coarse attitude. Using a radio crosslink, the two satellites will exchange state vector information and perform sub-meter level accuracy relative navigation. Each satellite will also contain a Microdischarge Plasma Thruster (MPT) developed at UT-Austin. This innovative device is capable of generating low-thrust, high-e±ciency propulsion at low power levels using microdischarge plasmas. The ability of the MPT to extend the life of the orbit will be determined by monitoring the orbit decay rates of the two vehicles as well as the MEMS IMU. A distributed tracking network with multiple university partners will be utilized to track the low Earth orbit satellites. Amateur radio experimenters, high schools, universities, and other interested parties will be encouraged to record telemetry from the satellites and report their data to a project web site for processing. Although the main purpose of the mission is technology demonstration, science goals will also be pursued. These include post-processing sensor measurements to determine satellite drag, as well as Earth atmospheric and magnetospheric studies

    Whole-genome sequencing reveals host factors underlying critical COVID-19

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    Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

    The Keuper Saliferous beds of the Droitwich area

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    1.50LD:7520.335(IGS-R--81/2) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

    MeerLICHT phot. of hot sub-luminous stars

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    A full list of 610 sdB candidates, similar to Table A.1 of the paper. Note that, here, the first column is different from the first column of Table A.1. (1 data file)

    Changing minds? Not in Congress!

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    This paper shows a variety of evidence that members of Congress are ideologically consistent. Based upon the roll call voting record, once elected to Congress, members adopt a consistent ideological position and maintain it over time. There may be changing minds, but they are not in Congress. Copyright Springer Science+Business Media, LLC 2007Congress, NOMINATE, Optimal Classification,

    The ecology of the European badger (Meles meles) in Ireland: a review

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    peer-reviewedThe badger is an ecologically and economically important species. Detailed knowledge of aspects of the ecology of this animal in Ireland has only emerged through research over recent decades. Here, we review what is known about the species' Irish populations and compare these findings with populations in Britain and Europe. Like populations elsewhere, setts are preferentially constructed on south or southeast facing sloping ground in well-drained soil types. Unlike in Britain, Irish badger main setts are less complex and most commonly found in hedgerows. Badgers utilise many habitat types, but greater badger densities have been associated with landscapes with high proportions of pasture and broadleaf woodlands. Badgers in Ireland tend to have seasonally varied diets, with less dependence on earthworms than some other populations in northwest Europe. Recent research suggests that females exhibit later onset and timing of reproductive events, smaller litter sizes and lower loss of blastocysts than populations studied in Britain. Adult social groups in Ireland tend to be smaller than in Britain, though significantly larger than social groups from continental Europe. Although progress has been made in estimating the distribution and density of badger populations, national population estimates have varied widely in the Republic of Ireland. Future research should concentrate on filling gaps in our knowledge, including population models and predictive spatial modelling that will contribute to vaccine delivery, management and conservation strategies.Department of Agriculture, Fisheries and FoodTeagasc Walsh Fellowship Programm
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