137 research outputs found
GOES-R Series GEO Side-Lobe Capable GPSR Post-Launch Refinements and Operational Capabilities
This paper addresses three topics: 1) EOPP (EOP (Earth Orientation Prediction) Parameters) file modification, 2) Kalman filter parameter tuning regarding maneuvers and 3) off-pointing GPS (Global Positioning System) tracking capability. GOES-R (Geostationary Operational Environmental Satellite-R Series) is the first in a 4-part series of new weather satellites set to replace and upgrade the older GOES constellation. Two GOES-R series have been launched to date, GOES-S and GOES-R. GOES-R is operational over the Eastern United States and GOES-S over the West. The Global Positioning System Receiver (GPSR) on board this geostationary weather satellite is a mission critical enabling technology which has been both tested on the ground and evaluated on-orbit to verify its effectivity. Since becoming operational in November 2016, the GPSR onboard has performed extremely well under nominal circumstances. Further refinements regarding a variety of facets have taken place since the launch of GOES-R. One such refinement was the implementation of a modified EOP (Earth Orientation Prediction) parameter set to improve ECEF (Earth Centered Earth Fixed) to ECI (Earth Centered Inertial) transformation by restoring zonal tides removed from the EOP parameter fit per tech note 36. Another relevant refinement combined thermal consideration with Kalman filter tuning to improve orbit determination performance during maneuvers. Now with two years of data and two vehicles in orbit many capabilities of the GPSR have been identified and defined to a higher degree. For example, metrics on side-lobe tracking and off-Nadir tracking capabilities have been quantified to a high degree. This paper will seek to supplement the ESA (European Space Agency) GNC 2017 GOES-R GPSR performance paper as a deeper dive on specific tracking capabilities and performance improvements now implemented on the GOES-R and GOES-S vehicles
miR-146a is a significant brake on autoimmunity, myeloproliferation, and cancer in mice
Excessive or inappropriate activation of the immune system can be deleterious to the organism, warranting multiple molecular mechanisms to control and properly terminate immune responses. MicroRNAs (miRNAs), ~22-nt-long noncoding RNAs, have recently emerged as key posttranscriptional regulators, controlling diverse biological processes, including responses to non-self. In this study, we examine the biological role of miR-146a using genetically engineered mice and show that targeted deletion of this gene, whose expression is strongly up-regulated after immune cell maturation and/or activation, results in several immune defects. Collectively, our findings suggest that miR-146a plays a key role as a molecular brake on inflammation, myeloid cell proliferation, and oncogenic transformation
Large Tandem, Higher Order Repeats and Regularly Dispersed Repeat Units Contribute Substantially to Divergence Between Human and Chimpanzee Y Chromosomes
Comparison of human and chimpanzee genomes has received much attention,
because of paramount role for understanding evolutionary step distinguishing us
from our closest living relative. In order to contribute to insight into Y
chromosome evolutionary history, we study and compare tandems, higher order
repeats (HORs), and regularly dispersed repeats in human and chimpanzee Y
chromosome contigs, using robust Global Repeat Map algorithm. We find a new
type of long-range acceleration, human-accelerated HOR regions. In peripheral
domains of 35mer human alphoid HORs, we find riddled features with ten
additional repeat monomers. In chimpanzee, we identify 30mer alphoid HOR. We
construct alphoid HOR schemes showing significant human-chimpanzee difference,
revealing rapid evolution after human-chimpanzee separation. We identify and
analyze over 20 large repeat units, most of them reported here for the first
time as: chimpanzee and human ~1.6 kb 3mer secondary repeat unit (SRU) and
~23.5 kb tertiary repeat unit (~0.55 kb primary repeat unit, PRU); human 10848,
15775, 20309, 60910, and 72140 bp PRUs; human 3mer SRU (~2.4 kb PRU); 715mer
and 1123mer SRUs (5mer PRU); chimpanzee 5096, 10762, 10853, 60523 bp PRUs; and
chimpanzee 64624 bp SRU (10853 bp PRU). We show that substantial
human-chimpanzee differences are concentrated in large repeat structures, at
the level of as much as ~70% divergence, sizably exceeding previous numerical
estimates for some selected noncoding sequences. Smeared over the whole
sequenced assembly (25 Mb) this gives ~14% human--chimpanzee divergence. This
is significantly higher estimate of divergence between human and chimpanzee
than previous estimates.Comment: 22 pages, 7 figures, 12 tables. Published in Journal of Molecular
Evolutio
The fate of rapidly labelled ribonucleic acid in the presence of actinomycin in normal and virus-infected animal cells
Synthesis of viral mRNA and polyadenylate by a ribonucleoprotein complex from extracts of VSV-infected cells
Characterization of the messenger RNA released from L cell polyribosomes as a result of temperature shock
Evidence that all messenger RNA molecules (except histone messenger RNA) contain poly(A) sequences and that the poly(A) has a nuclear function
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