Results 81 to 90 of about 2,642,880 (286)

High-precision GPS orbit determination by integrating the measurements from regional ground stations and LEO onboard receivers

Satellite Navigation
High-precision Global Navigation Satellite System (GNSS) orbit and clock products are crucial for precise applications. An evenly distributed global network enables continuous tracking for GNSS satellites, while a regional network may result in tracking ...
Kai Li, Chengpan Tang, Shanshi Zhou, Xiaogong Hu, Xuhua Zhou   +4 more
doaj   +1 more source

Structural and biochemical analysis of a B12 superbinder

FEBS Letters, EarlyView.
BtuG proteins are vitamin B12 scavengers in Bacteroides thetaiotaomicron, a dominant human gut bacterium. We present crystal structures of three BtuG homologs bound to cobalamin and its precursor cobinamide, revealing picomolar binding affinities, among the highest known for any natural protein.
Jose M. Martinez Felices, Jacob J. Whittaker, Dirk J. Slotboom, Albert Guskov   +3 more
wiley   +1 more source

Phoenix-XNS - A Miniature Real-Time Navigation System for LEO Satellites [PDF]

, 2006
The paper describes the development of a miniature GPS receiver with integrated real-time navigation system for orbit determination of satellites in low Earth orbit (LEO).
Gill, Eberhard, Montenbruck, Oliver
core  

Structures of mycobacterial 3‐methylcrotonyl‐CoA carboxylase reveal carrier‐domain translocation between catalytic sites

FEBS Letters, EarlyView.
Mycobacterial 3‐methylcrotonyl‐CoA carboxylase uses a mobile biotin‐carrying domain to shuttle a carboxyl group between two catalytic sites, enabling carboxylation of 3‐methylcrotonyl‐CoA during leucine breakdown. Cryo‐electron microscopy captures the carrier at both sites and reveals an inward loop movement that may prevent futile rebinding to the ...
Ajit Yadav, Bogdan I. Florea, Sebastian Geibel   +2 more
wiley   +1 more source

Estimating maneuvers for precise relative orbit determination using GPS

, 2016
Precise relative orbit determination is an essential element for the generation of science products from distributed instrumentation of formation flying satellites in low Earth orbit. According to the mission profile, the required formation is typically
Urs Hugentobler, Jean-Sébastien Ardaens, Gerardo Allende-Alba, Allende Alba, Gerardo, Hugentobler, Urs, Oliver Montenbruck, Ardaens, Jean-Sébastien, Montenbruck, Oliver, Wermuth, Martin, Martin Wermuth, Allende-Alba, G.;Montenbruck, O.;Ardaens, J.-S.;Hugentobler, U.   +10 more
core   +1 more source

From junk to function — How weak selection in eukaryotes builds new parts and drives genomic complexity

FEBS Letters, EarlyView.
How do genomes gain new functional parts? In eukaryotes, which tend to evolve under weak selection, much of the genome is junk. Palazzo and Qiu borrow the logic of Markov chains to show how non‐functional DNA becomes functional through the appearance of intermediate states, which arise due to epistasis, buffering, and biochemical messiness, allowing ...
Alexander F. Palazzo, Yi Qiu
wiley   +1 more source

Precise Orbit Determination of GPS Satellites Using Phase Observables [PDF]

Journal of Astronomy and Space Sciences, 1997
The accuracy of user position by GPS is heavily dependent upon the accuracy of satellite position which is usually transmitted to GPS users in radio signals.
Myung-Kook Jee, Kyu-Hong Choi, Pil-Ho Park   +2 more
doaj  

The Shewanella oneidensis Fic enzyme SoFic targets the switch‐I region of EF‐Tu for AMPylation

FEBS Letters, EarlyView.
Fic enzymes mediate diverse post‐translational modifications across all domains of life, including AMPylation. Prokaryotic EF‐Tu can be AMPylated and deAMPylated by the conserved Fic enzyme SoFic. Structural and biochemical approaches were used to characterize the effect of AMPylation on EF‐Tu, SoFic's enzymatic activities, and the enzyme‐target ...
Svenja Runge, Vivian Pogenberg, Alexander Baumgart, Bente Siebels, Hartmut Schlüter, Michael Hecht‐Bucher, Aymelt Itzen   +6 more
wiley   +1 more source

Precise orbit determination of Haiyang-2 using satellite laser ranging

, 2013
With the successful launch and official commissioning of China's first dynamic ocean environment satellite Haiyang-2 (HY-2), China's capabilities for oceanic environment monitoring and oceanic resource detecting have been further improved and enhanced ...
Wu Bin, Zhao Gang, Zhou XuHua
core  

Chiral separation of chloroalkanes with the chromatographic column onboard Martian rovers

FEBS Letters, EarlyView.
Computer image of the Rosalind Franklin Rover of ESA's ExoMars mission. ExoMars is scheduled to land on planet Mars in Oxia Planum in 2029. This area represents an interesting spot to look for biosignatures. Investigations of ExoMars include measurement on molecular chirality. We show that chiral chloroalkanes, that have been identified on Mars, can be
Asma Merzougui, Agnes Banreti, Armelle L. Ernst, Guillaume Leseigneur, Uwe J. Meierhenrich   +4 more
wiley   +1 more source