Single station Doppler tracking for satellite orbit prediction and propagation

textPresently, there are two main methods of launching a cube satellite into Earth orbit. The first method is to purchase a secondary payload slot on a major launch vehicle. For the second method, the satellite must first be transported via a major launch vehicle to the International Space Station. From there, the satellite is loaded into one of two deployment mechanisms, and deployed at a specified time. In each case, the satellite's initial orbit is not accurately known. For ground operators this poses a problem of position uncertainty. In order to solve this problem, a satellite tracking algorithm was developed to use an initial two-line element set for coarse orbit prediction, followed by Doppler measurements for continuous processing and updating. The system was tested using simulated data. The analysis showed that this low-cost, scalable system will satisfy the tracking requirements of many cube satellite missions, including current missions at the University of Texas.Aerospace Engineerin

Contribution of LANDSAT-4 thematic mapper data to geologic exploration

The increased number of carefully selected narrow spectral bands and the increased spatial resolution of thematic mapper data over previously available satellite data contribute greatly to geologic exploration, both by providing spectral information that permits lithologic differentiation and recognition of alteration and spatial information that reveals structure. As vegetation and soil cover increase, the value of spectral components of TM data decreases relative to the value of the spatial component of the data. However, even in vegetated areas, the greater spectral breadth and discrimination of TM data permits improved recognition and mapping of spatial elements of the terrain. As our understanding of the spectral manifestations of the responses of soils and vegetation to unusual chemical environments increases, the value of spectral components of TM data to exploration will greatly improve in covered areas

Geologic exploration: The contribution of LANDSAT-4 thematic mapper data

The major advantages of the TM data over that of MSS systems are increased spatial resolution and a greater number of narrow, strategically placed spectral bands. The 30 meter pixel size permits finer definition of ground features and improves reliability of the photointerpretation of geologic structure. The value of the spatial data increases relative to the value of the spectral data as soil and vegetation cover increase. In arid areas with good exposure, it is possible with careful digital processing and some inventive color compositing to produce enough spectral differentiation of rock types and thereby produce facsimiles of standard geologic maps with a minimum of field work or reference to existing maps. Hue-saturation value images are compared with geological maps of Death Valley, California, the Big Horn/Wind River Basin of Wyoming, the area around Cement, Oklahoma, and Detroit. False color composites of the Ontario region are also examined

For Life Abundant: Practical Theology, Theological Education, and Christian Ministry

Reviewed by Matt Floding

Intracerebral Hemorrhage and Ischemic Stroke of Different Etiologies Have Distinct Alternatively Spliced mRNA Profiles in the Blood: a Pilot RNA-seq Study.

Whole transcriptome studies have used 3'-biased expression microarrays to study genes regulated in the blood of stroke patients. However, alternatively spliced messenger RNA isoforms have not been investigated for ischemic stroke or intracerebral hemorrhage (ICH) in animals or humans. Alternative splicing is the mechanism whereby different combinations of exons of a single gene produce distinct mRNA and protein isoforms. Here, we used RNA sequencing (RNA-seq) to determine if alternative splicing differs for ICH and cardioembolic, large vessel and lacunar causes of ischemic stroke compared to controls. RNA libraries from 20 whole blood samples were sequenced to 200 M 2 × 100 bp reads using Illumina sequencing-by-synthesis technology. Differential alternative splicing was assessed using one-way analysis of variance (ANOVA), and differential exon usage was calculated. Four hundred twelve genes displayed differential alternative splicing among the groups (false discovery rate, FDR; p < 0.05). They were involved in cellular immune response, cell death, and cell survival pathways. Distinct expression signatures based on usage of 308 exons (292 genes) differentiated the groups (p < 0.0005; fold change >|1.2|). This pilot study demonstrates that alternatively spliced genes from whole blood differ in ICH compared to ischemic stroke and differ between different ischemic stroke etiologies. These results require validation in a separate cohort

Enrichment of Two Isomeric Heparin Oligosaccharides Exhibiting Different Affinities toward Monocyte Chemoattractant Protein-1

Chemokine-GAG interactions are crucial to facilitate chemokine immobilization, resulting in the formation of chemokine gradients that guide cell migration. Here we demonstrate chromatographic isolation and purification of two heparin hexasaccharide isomers that interact with the oligomeric chemokine Monocyte Chemoattractant Protein-1 (MCP-1)/CCL2 with different binding affinities. The sequences of these two hexasaccharides were deduced from unique MS/MS product ions and HPLC compositional analysis. Ion mobility mass spectrometry (IM-MS) showed that the two isolated oligosaccharides have different conformations and both displayed preferential binding for one of the two distinct conformations known for MCP-1 dimers. A significant shift in arrival time distribution of close to 70 Å2 was observed, indicating a more compact protein:hexasaccharide conformation. Clear differences in the MS spectra between bound and unbound protein allowed calculation of Kd values from the resulting data. The structural difference between the two hexasaccharides was defined as the differential location of a single sulfate at either C-6 of glucosamine or C-2 of uronic acid in the reducing disaccharide, resulting in a 200-fold difference in binding affinity for MCP-1. These data indicate sequence specificity for high affinity binding, supporting the view that sulfate position, and not simply the number of sulfates, is important for heparan sulfate protein binding

Timing of the Acadian Orogeny in northern New Hampshire

New U‐Pb geochronology constrains the timing of the Acadian orogeny in the Central Maine Terrane of northern New Hampshire. Sixteen fractions of one to six grains each of zircon or monazite have been analyzed from six samples: (1) an early syntectonic diorite that records the onset of the Acadian; (2) a schist, a migmatite, and two granites that together record the peak of the Acadian; and (3) a postkinematic pluton that records the end of the Acadian. Zircon from the syntectonic Wamsutta Diorite gives a 207Pb/206Pb age of circa 408 Ma, the time at which the boundary between the deforming orogenic wedge and the foreland basin was in the vicinity of the Presidential Range. This age agrees well with the Emsian position of the northwest migrating Acadian orogenic front and records the beginning of the Acadian in this part of the Central Maine Terrane. We propose a possible Acadian tectonic model that incorporates the geochronologic, structural, and stratigraphic data. Monazite from the schist, migmatite, Bigelow Lawn Granite, and Slide Peak Granite gives 207Pb/206U ages, suggesting the peak of Acadian metamorphism and intrusion of two‐mica granites occurred at circa 402–405 Ma, the main pulse of Acadian orogenesis. Previously reported monazite ages from schists that likely record the peak metamorphism in the Central Maine Terrane of New Hampshire and western Maine range from circa 406–384 Ma, with younger ages in southeastern New Hampshire and progressively older ages to the west, north, and northeast. Acadian orogenesis in the Presidential Range had ended by circa 355 Ma, the 207Pb/235U age of monazite from the Peabody River Granite. From 408 to perhaps at least 394 Ma, Acadian orogenesis in the Presidential Range was typical of the tectonic style, dominated by synkinematic metamorphism, seen in central and southern New Hampshire, Massachusetts, and Connecticut. From no earlier than 394 Ma to as late as 355 Ma, the orogenesis was typical of the style in parts of Maine dominated by postkinematic metamorphism

Changes in the Proliferative Activity of Human Hematopoietic Stem Cells in NOD/SCID Mice and Enhancement of Their Transplantability after In Vivo Treatment with Cell Cycle Inhibitors

Human hematopoietic tissue contains rare stem cells with multilineage reconstituting ability demonstrable in receptive xenogeneic hosts. We now show that within 3 wk nonobese diabetic severe combined immunodeficiency (NOD/SCID) mice transplanted with human fetal liver cells regenerate near maximum levels of daughter human hematopoietic stem cells (HSCs) able to repopulate secondary NOD/SCID mice. At this time, most of the human HSCs (and other primitive progenitors) are actively proliferating as shown by their sensitivity to treatments that kill cycling cells selectively (e.g., exposure to high specific-activity [3H]thymidine in vitro or 5-fluorouracil in vivo). Interestingly, the proliferating human HSCs were rapidly forced into quiescence by in vivo administration of stromal-derived factor-1 (SDF-1) and this was accompanied by a marked increase in the numbers of human HSCs detectable. A similar result was obtained when transforming growth factor-β was injected, consistent with a reversible change in HSCs engrafting potential linked to changes in their cell cycle status. By 12 wk after transplant, most of the human HSCs had already entered Go and treatment with SDF-1 had no effect on their engrafting activity. These findings point to the existence of novel mechanisms by which inhibitors of HSC cycling can regulate the engrafting ability of human HSCs executing self-renewal divisions in vivo