Optical links in the angle-data assembly of the 70-meter antennas

In the precision-pointing mode the 70 meter antennas utilize an optical link provided by an autocollimator. In an effort to improve reliability and performance, commercial instruments were evaluated as replacement candidates, and upgraded versions of the existing instruments were designed and tested. The latter were selected for the Neptune encounter, but commercial instruments with digital output show promise of significant performance improvement for the post-encounter period

Ranging system which compares an object reflected component of a light beam to a reference component of the light beam

A system is described for measuring the distance to an object by comparing a first component of a light pulse that is reflected off the object with a second component of the light pulse that passes along a reference path of known length, which provides great accuracy with a relatively simple and rugged design. The reference path can be changed in precise steps so that it has an equivalent length approximately equal to the path length of the light pulse component that is reflected from the object. The resulting small difference in path lengths can be precisely determined by directing the light pulse components into opposite ends of a detector formed of a material that emits a second harmonic light output at the locations where the opposite going pulses past simultaneously across one another

Effects of temperature and diet on the growth rate of year 0 oyster toadfish, Opsanus tau

Author Posting. © Marine Biological Laboratory, 2006. This article is posted here by permission of Marine Biological Laboratory for personal use, not for redistribution. The definitive version was published in Biological Bulletin 210 (2006): 64-71.The effects of temperature and diet on the growth of captive year 0 specimens of Opansus tau were examined for two consecutive year classes. The 2001 year class was raised at about 23, 26, or 29°C and provided with live brine shrimp, frozen butterfish and squid, or commercial food pellets (45% protein, 19% fat, and 3% fiber) three times per week. Maximal growth was achieved with the pellet diet, and fish raised at 29°C attained the highest mean wet weight (84.0 g ± 14.6 g SE) and fastest instantaneous relative growth rate (IRGR, 1.79% body weight/d). The 2002 year class was raised on the same pellet diet at 31.5°C and fed 3, 5, or 7 times per week. Although more frequent feedings led to significantly greater mean wet weight in the first half of the year, by month 12 there was no significant difference between the three feeding frequencies. These fish weighed approximately 68g and had an average IRGR of 1.74% body weight/d. The pellet diet during both years was correlated with high survival (> 75%).Support was provided by the Marine Models in Biological Research Program, the University of Minnesota Grant in Aid, the NASA Life Science Fellowship, the MBL Associates Fellowship, and NIH grant DC01837

Lucky Imaging: High Angular Resolution Imaging in the Visible from the Ground

We use a Lucky Imaging system to obtain I-band images with much improved angular resolution on a ground-based 2.5m telescope. We present results from a 10-night assessment campaign on the 2.56m Nordic Optical Telescope and quantify the performance of our system in seeings better than 1.0''. In good seeing we have acquired near diffraction-limited images; in poorer seeing the angular resolution has been routinely improved by factors of 2.5-4. The system can use guide stars as faint as I=16 with full performance and its useful field of view is consistently larger than 40" diameter. The technique shows promise for a number of science programmes, both galactic (eg. binary candidates, brown dwarfs, globular cluster cores) and extragalactic (eg. quasar host galaxies, damped Lyman-alpha absorbers).Comment: 7 pages, 10 figures, submitted to A&A. For further information, see http://www.ast.cam.ac.uk/~optics/Lucky_Web_Site

A case of May-Thurner syndrome

May-Thurner syndrome is a condition that results from narrowing of the left common iliac vein lumen due to pressure from the right common iliac artery as it crosses anterior to it. We describe a very rare case in which a previously asymptomatic patient presented with May-Thurner syndrome

Impediments to U.S. wheat exports and reasons for decline in world market share

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

The lumbosacral angle does not reflect progressive tethered cord syndrome in children with spinal dysraphism

Purpose: Our goal was to validate the hypothesis that the lumbosacral angle (LSA) increases in children with spinal dysraphism who present with progressive symptoms and signs of tethered cord syndrome (TCS), and if so, to determine for which different types and/or levels the LSA would be a valid indicator of progressive TCS. Moreover, we studied the influence of surgical untethering and eventual retethering on the LSA. Methods: We retrospectively analyzed the data of 33 children with spinal dysraphism and 33 controls with medulloblastoma. We measured the LSA at different moments during follow-up and correlated this with progression in symptomatology. Results: LSA measurements had an acceptable intra- and interobserver variability, however, some children with severe deformity of the caudal part of the spinal column, and for obvious reasons those with caudal regression syndrome were excluded. LSA measurements in children with spinal dysraphism were significantly different from the control group (mean LSA change, 21.0° and 3.1° respectively). However, both groups were not age-matched, and when dividing both groups into comparable age categories, we no longer observed a significant difference. Moreover, we did not observe a significant difference between 26 children with progressive TCS as opposed to seven children with stable TCS (mean LSA change, 20.6° and 22.4° respectively). Conclusions: We did not observe significant differences in LSA measurements for children with clinically progressive TCS as opposed to clinically stable TCS. Therefore, the LSA does not help the clinician to dete

Unusual formation of the musculocutaneous and median nerves: a case report refined by intraneural dissection and literature review

This report presents a detailed anatomical investigation of an upper limb specimen showing an atypical formation of the musculocutaneous nerve (MCN) and median nerve (MN). The study was refined by intraneural dissection, which supplements earlier descriptions of similar anatomical variations and allows for revision of the accepted classification.The case described in this report was an incidental finding during routine dissection of a fixed isolated upper limb. Intraneural dissection revealed partial fusion between the MCN and aberrant bundles of the MN. Those aberrant bundles joined the main steam of the MN at the level at which the MCN branched off as an independent nerve. The procedure allowed the aberrant fibres of the MN to be differentiated from the MCN. The presence of separate bundles in a territory corresponding to the MCN was confirmed, although those bundles and the aberrant MN bundles were covered by a common epineurium. The aberrant MN bundles running within the MCN did not contribute to innervation of the forearm muscles. They rejoined the main nerve trunk in the arm.A comprehensive understanding of the diverse anatomical variations of the upper limb nerves could be crucial for the safety and success of surgical procedures, especially procedures for reconstructing the brachial plexus or its branches

Nucleon Spin Fluctuations and the Supernova Emission of Neutrinos and Axions

In the hot and dense medium of a supernova (SN) core, the nucleon spins fluctuate so fast that the axial-vector neutrino opacity and the axion emissivity are expected to be significantly modified. Axions with m_a\alt10^{-2}\,{\rm eV} are not excluded by SN~1987A. A substantial transfer of energy in neutrino-nucleon ($\nu N$) collisions is enabled which may alter the spectra of SN neutrinos relative to calculations where energy-conserving $\nu N$ collisions had been assumed near the neutrinosphere.Comment: 8 pages. REVTeX. 2 postscript figures, can be included with epsf. Small modifications of the text, a new "Note Added", and three new references. To be published in Phys. Rev. Let

Particle-hole state densities with non-equidistant single-particle levels

The correct use of energy-dependent single-particle level (s.p.l.) densities within particle-hole state densities based on the equidistant spacing model (ESM) is analysed. First, an analytical expression is obtained following the convolution of energy-dependent excited-particle and hole densities. Next, a comparison is made with results of the ESM formula using average s.p.l. densities for the excited particles and holes, respectively. The Fermi-gas model (FGM) s.p.l. densities calculated at the corresponding average excitation energies are used in both cases. The analysis concerns also the density of particle-hole bound states. The pairing correlations are taken into account while the comparison of various effects includes the exact correction for the Pauli exclusion principle. Quantum-mechanical s.p.l. densities and the continuum effect can also match a corresponding FGM formula, suitable for use within the average energy-dependent partial state density in multistep reaction models.Comment: 29 pages, ReVTeX, 11 postscript figures, submitted to Phys.Rev.