2,414 research outputs found
Hayes, Mrs. RB
No full textTitle from unverified information on negative sleeve.Annotation from negative, penciled on emulsion: Mrs. Hayes, 3946.Forms part of Brady-Handy Photograph Collection (Library of Congress)
Hayes, President Rutherford B. and two sons
No full textTitle from unverified information on negative sleeve.Annotation from negative, scratched into emulsion: 2028, RB Hayes, 1198 [crossed out].Forms part of Brady-Handy Photograph Collection (Library of Congress)
Optimal cooling strategies for magnetically trapped atomic Fermi-Bose mixtures
No full textWe discuss cooling efficiency for different-species Fermi-Bose mixtures in magnetic traps. A better heat capacity matching between the two atomic species is achieved by a proper choice of the Bose cooler and the magnetically trappable hyperfine states of the mixture. When a partial spatial overlap between the two species is also taken into account, the deepest Fermi degeneracy is obtained for an optimal value of the trapping frequency ratio between the two species. This can be achieved by assisting the magnetic trap with a deconfining light beam, as shown in the case of fermionic Li-6 mixed with Na-23, Rb-87, and Cs-133, with optimal conditions found for the not yet explored Li-6-Rb-87 mixture
Development of an apparatus for cooling Li-6-Rb-87 Fermi-Bose mixtures in a light-assisted magnetic trap
No full textWe describe an experimental setup designed to produce ultracold trapped gas clouds of fermionic (6)Li and bosonic (87)Rb. This combination of alkali metals has the potential to reach deeper Fermi degeneracy with respect to other mixtures since it allows for improved heat capacity matching which optimizes sympathetic cooling efficiency. Atomic beams of the two species are independently produced and then decelerated by Zeeman slowers. The slowed atoms are collected into a magneto-optical trap and then transferred into a quadrupole magnetic trap. An ultracold Fermi gas with temperature in the 10(-3)T(F) range should be attainable through selective confinement of the two species via a properly detuned laser beam focused in the center of the magnetic trap
Liquid structure of Rb-Hg alloys studied by neutron diffraction
No full textThe structures of liquid Rb–Hg alloys were studied as a function of composition by neutron diffraction. In the intermediate Rb concentration range, the obtained structure factors show a small prepeak, which may be an evidence of the formation of Hg polyanion units in liquids. The Reverse Monte Carlo (RMC) analysis was applied to separate the total radial distribution function into the corresponding partial radial distribution functions. Up to 10 at.% Rb, no obvious changes are found for the first peak position of the partial radial distribution functions of the Hg–Hg pair and that of the Hg–Rb pair. The first peak position between the Hg–Rb pairs increases above 20 at.% Rb. In addition to the first peak, a subpeak between Hg–Hg pairs can be seen in the large distance. At 60 at.% Rb, the nearest neighbor distance between Hg atoms shows the closest value in the concentration range studied. These results indicate that with the progress of charge transfer the solvation structure in the dilute Rb concentration range changes into the structure containing polyanions composed of Hg species
Fractional Edge Cover Number of Model RB
No full textModel RB is a random constraint satisfaction problem with a growing domain size, which exhibits exact phase transition phenomena. Many hard instances with planted solutions can be generated via Model RB, to be used as benchmarks for algorithmic competitions and researches. In the past, some structural parameters of constraint hypergraphs are analyzed to show hardness of Model RB, such as hinge width, decycling number, treewidth, and hypertree width. In this paper, one more structural parameter of constraint hypergraphs of Model RB, namely the fractional edge cover number, is analyzed. We show upper and lower bounds on the fractional edge cover number of Model RB. In particular, the fractional edge cover number of Model RB is shown to be asymptotically linear in the number of variables, like hinge width, decycling number, treewidth and hypertree width. These results together provide further evidences on the hardness of Model RB.EICPCI-S(ISTP)[email protected]
MILLIMETER-WAVE SPECTROSCOPY OF COLD RB ATOMS
No full textAuthor Institution: Department of Physics, University of Virginia, McCormick Road, Charlottesville, Virginia 22903Cold Rb atoms were prepared by magneto-optical trap. Millimeter-wave has been used to drive nd to (n-2)f one-photon and nd to (n-1)g () two-photon transitions. Quantum defects of f and g states of Rb were calculated. Full analyses will be presented. }
Interpretation and the Problem of the Intention of the Author, by Burhanetir Tatar
No full textBurhanetir Tatar, Interpretation and the Problem of the Intention of the Author: H.G. Gadamer vs E.D. Hirsh, The Council for Research in Values and Philosophy, 199
Variation in Anthocyanin Production Among Accessions and Cultivars of Rought Bluegrass
No full textFood, Agricultural, and Environmental Sciences (FAES): 3rd Place (The Ohio State University Edward F. Hayes Graduate Research Forum)When under biotic or abiotic stress many plants possess the ability to synthesize anthocyanins, red or blue secondary pigments. The stress induction of anthocyanin biosynthesis has only been studied on a small sample of species. In order to meet the demand for this natural product, it’s essential to evaluate anthocyanin biosynthesis in other species. Turfgrasses are a group of perennial monocots that can withstand constant aggressive harvesting without effecting the growth of new tissues; therefore metabolites of interest could be harvested over and over on the same plant(s). One turfgrass species of interest, rough bluegrass (RB - Poa trivialis L.), is known to exhibit visible concentrations of anthocyanins in nature. Previous experiments using this species (cv. ‘Havana’) showed that when exposed to prolonged high irradiance white light, anthocyanin concentration could increase by 12,000% or more The purpose of this study was to first determine if the ability to up-regulate anthocyanin synthesis is variable among RB accessions, and second to determine what may limit anthocyanin synthesis among these accessions. Nineteen accessions and 6 cultivars of RB were compared for their ability to up-regulate anthocyanin synthesis under non-intermittent blue LED irradiation for 5 days. Results show that not all accessions and cultivars of this species are equal in their ability to induce high quantities of anthocyanins. However, supplementary analysis of these samples showed that those plants that do not produce high concentrations of anthocyanins may just be producing high concentrations of other flavonoid compounds. A five-year embargo was granted for this item
Aneuploidy in spermatids of Robertsonian (Rb) chromosome heterozygous mice
No full text© 2014, The Author(s). Rb translocations are chromosomal rearrangements frequently found in natural populations of the house mouse Mus musculus domesticus. The standard diploid karyotype of the house mouse consisting of 40 telocentric chromosomes may be reduced by the emergence of metacentric Rb chromosomes. Multiple simple Rb heterozygotes form trivalents exhibiting higher anaphase nondisjunction frequency and consequently higher number of unbalanced gametes than in normal males. This work will attempt to establish whether frequencies of aneuploidy observed in heterozygote spermatids of the house mouse M. musculus domesticus show differences in chromosomes derived from different trivalents. Towards this goal, the number and distribution frequency of aneuploidy was assessed via FISH staining of specific chromosomes of spermatids derived from 2n = 32 individuals. Our results showed that for a given set of target chromosomes, 90 % of the gametes were balanced, resulting from alternate s
- …
