1,233 research outputs found
Distance to U Pegasi by the DDE Algorithm
A distance is found for the W UMa type binary U Pegasi, with a newly modified
version of the Wilson-Devinney program (W-D) that makes use of the direct
distance estimation (DDE) algorithm. The reported distance of d = 123.6pc is an
average based on solutions for B and V data and a primary star temperature of
5800K. Standardized light curves (not differential), radial velocities, and a
spectroscopic primary star temperature are input to the pro- gram. Differential
corrections were performed for each light curve band along with the velocities
for two primary temperatures that span 100K. Log10d is a model parameter like
many others that are adjustable in W-D. The eclipsing binary distance agrees
with the Hipparcos parallax distance and is more precise.Comment: 2 pages, 1 table, International Conference: Binaries - Key to
Comprehension of the Universe, Brno, Czech Republic June 8-12, 200
Cables1 links Slit/Robo and Wnt/Frizzled signaling in commissural axon guidance
During neural circuit formation, axons navigate from one intermediate target to the next, until they reach their final target. At intermediate targets, axons switch from being attracted to being repelled by changing the guidance receptors on the growth cone surface. For smooth navigation of the intermediate target and the continuation of their journey, the switch in receptor expression has to be orchestrated in a precisely timed manner. As an alternative to changes in expression, receptor function could be regulated by phosphorylation of receptors or components of signaling pathways. We identified Cables1 as a linker between floor-plate exit of commissural axons, regulated by Slit/Robo signaling, and the rostral turn of post-crossing axons, regulated by Wnt/Frizzled signaling. Cables1 localizes β-catenin, phosphorylated at tyrosine 489 by Abelson kinase, to the distal axon, which in turn is necessary for the correct navigation of post-crossing commissural axons in the developing chicken spinal cord
Determination of iohexol in canine plasma – strong correlation between enzyme-linked immunosorbent assay, high-performance liquid chromatography, and neutron activation analysis
Iohexol is a non-radioactive, iodinated, water-soluble radiographic contrast medium that is widely used in detection imaging for both clinical and scientific purposes. It has also been used as a marker for glomerular filtration rate (GFR) and intestinal permeability (IP) in both humans and animals, such as dogs, rats and cats. Currently, iohexol is determined mainly by high-performance liquid chromatography (HPLC) methods which limit its use in veterinary clinical practice. The aim of this study was to validate an enzyme-linked immunosorbent assay (ELISA) and its accuracy for the measurement of iohexol in canine plasma by comparison with HPLC and neutron activation analysis (NAA). Blank and iohexol-containing blood samples (n=100) from Beagle dogs were collected from the jugular vein in lithium heparin tubes before and after intravenous application of 3.0 g iohexol/dog via the cephalic vein.
The results of this study show that the correlation coefficients when comparing ELISA vs. HPLC (r=0.99), ELISA vs. NAA (r=0.99) and HPLC vs. NAA (r=0.98) are all excellent. In conclusion, the measurement of iohexol from canine plasma using ELISA is as reproducible and reliable as using HPLC or NAA. However, using ELISA for measuring iohexol may be more practical, economical and useful for clinical practice and research than using HPLC or NAA
LP133-373 A New Chromospherically Active Eclipsing dMe Binary with a Distant, Cool White Dwarf Companion
We report the discovery of the partially eclipsing binary LP 133-373. Nearly identical eclipses along with observed photometric colors and spectroscopy indicate that it is a pair of chromospherically active dM4 stars in a circular 1.6 day orbit. Light and velocity curve modeling to our differential photometry and velocity data show that each star has a mass and radius of 0.340 ± 0.014 M☉ and 0.33 ± 0.02 R☉. The binary is itself part of a common proper motion pair with LP 133-374, a cool DC or possible DA white dwarf with a mass of 0.49-0.82 M☉, which would make the system at least 3 Gyr old
Experimental demonstration of quantum source coding
We report an experimental demonstration of Schumacher's quantum noiseless
coding theorem. Our experiment employs a sequence of single photons each of
which represents three qubits. We initially prepare each photon in one of a set
of 8 non-orthogonal codeword states corresponding to the value of a block of
three binary letters. We use quantum coding to compress this quantum data into
a two-qubit quantum channel and then uncompress the two-qubit channel to
restore the original data with a fidelity approaching the theoretical limit.Comment: 5 pages, 4 figure
LP 133-373: A New Chromospherically Active Eclipsing dMe Binary with a Distant, Cool White Dwarf Companion
We report the discovery of the partially eclipsing binary LP 133-373. Nearly identical eclipses along with observed photometric colors and spectroscopy indicate that it is a pair of chromospherically active dM4 stars in a circular 1.6 day orbit. Light and velocity curve modeling to our differential photometry and velocity data show that each star has a mass and radius of 0:340 ± 0:014 MꙨ and 0:33 ± 0:02 RꙨ. The binary is itself part of a common proper motion pair with LP 133-374, a cool DC or possible DA white dwarf with a mass of 0.49Y0.82 MꙨ, which would make the system at least 3 Gyr old
LP 133-373: A New Chromospherically Active Eclipsing dMe Binary with a Distant, Cool White Dwarf Companion
We report the discovery of the partially eclipsing binary LP 133-373. Nearly identical eclipses along with observed photometric colors and spectroscopy indicate that it is a pair of chromospherically active dM4 stars in a circular 1.6 day orbit. Light and velocity curve modeling to our differential photometry and velocity data show that each star has a mass and radius of 0.340+/-0.014 Msolar and 0.33+/-0.02 Rsolar. The binary is itself part of a common proper motion pair with LP 133-374, a cool DC or possible DA white dwarf with a mass of 0.49-0.82 Msolar, which would make the system at least 3 Gyr ol
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