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Creator | Title | Description | Subject | Date |
551 |
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DeTar, Carleton | Exotic mesons in quenched lattice QCD | Since gluons in QCD are interacting fundamental constituents just as quarks are, we expect that in addition to mesons made from a quark and an antiquark, there should also be glueballs and hybrids ~bound states of quarks, antiquarks, and gluons!. In general, these states would mix strongly with th... | Hybrid mesons; Antiquarks | 1997-12 |
552 |
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Vardeny, Zeev Valentine | Experimental determination of the charge/neutral branching ratio η in the photoexcitation of ∏-conjugated polymers by broadband ultrafast spectroscopy | We demonstrate a long-sought reliable method for determining the important branching ratio η between photogenerated charged polarons and neutral excitons in ∏-conjugated polymer films and solutions, using femtosecond transient photomodulation spectroscopy with broad spectral range from 0.14 to ... | pi-conjugated polymers; Charge/neutral branching ratio; Photoexcitation; nu value; Broadband ultrafast spectroscopy | 2007-02 |
553 |
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Boehme, Christoph | Experimental discrimination of geminate and non-geminate recombination in a-Si:H | A study of charge-carrier recombination in intrinsic hydrogenated amorphous silicon (a-Si:H) is presented using pulsed electrically and pulsed optically detected magnetic-resonance spectroscopies in order to measure the influence of spin-dependent recombination on photoluminescence (PL) and photoc... | Geminate recombination | 2009-05 |
554 |
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Lupton, John Mark | Experimental evidence for exciton scaling effects in self-assembled molecular wires | Resonant Rayleigh scattering from self-assembled one-dimensional molecular J-aggregate wires reveals a distinct dependence of the exciton energy on the width of lateral extension. For the J aggregates used in this study, strong in-line dipole coupling leads to a delocalization of the exciton wave fu... | Exciton scaling effects; Molecular wires; J-aggregate wires; Quantum wires | 2004-12 |
555 |
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Davidson, Diane W. | Experimental manipulation of food bodies in Cecropia | Neotropical Cecropia trees range from Mexico to Argentina and are typical of disturbed habitats. Cecropia plants provide food and housing for the ants in return for known or presumed protection from herbivores and vine cover. Glycogen-rich Mullerian bodies (MB's) are the predominant food source for ... | Mullerian bodies; Trichilia; Cecropia tessmannii; Cecropia pungara | 1992 |
556 |
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Davidson, Diane W. | Experimental studies of species-specificity in cecropia-ant relationships | Strict coevolution requires that interactions among organisms be speciesspecific. We assessed the relative roles of host- and habitat-specificity in determining the match between a genus of myrmecophytic trees and a guild of obligate plant-ants in the moist tropical forests of Madre de Dios, Peru. F... | Ant-plant; Ants; Cecropia; Coevolution; Colonization; Coordinated dispersal; Ecological fitting; Habitat-specificity; Host-specificity; Mutualism; Parasitoid wasps; Preadaptation | 1997 |
557 |
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Ehleringer, James R.; Cerling, Thure E.; Dearing, Maria-Denise | Experimental study of carbon-isotope fractionation between diet, hair, and feces of mammalian herbivores | The carbon-isotope composition of hair and feces offers a glimpse into the diets of mammalian herbivores. It is particularly useful for determining the relative consumption of browse and graze in tropical environments, as these foods have strongly divergent carbon-isotope compositions. Fecal ?13C v... | Fractionation; Mammalian herbivores; Medicago sativa; Cynodon dactylon | 2003 |
558 |
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Davidson, Diane W. | Experimental study of diffuse competition in harvester ants | Experiments carried out over a 5-yr period in the Chihuahuan Desert support the a priori prediction of diffuse competition between two species of harvester ants. Despite dietary overlap between a large species {Pogonomyrmex rugosus) and a small species (Pheidole xerophila), the large species facilit... | Chihuahuan Desert; Ants; Facilitation; Resource allocation; Granivory | 1985 |
559 |
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Goller, Franz | Experimental support for a model of birdsong production | In this work we present an experimental validation of a recently proposed model for the production of birdsongs. We have previously observed that driving the model with simple functions of time, which represent tensions in vocal muscles, produces a wide variety of sounds resembling birdsongs. In th... | Vocal; Muscles; Syrinx | 2003 |
560 |
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Clayton, Dale H. | Experimental test of the importance of preen oil in Rock Doves (Columba livia) | Most species of birds have a uropygial gland, also known as a preen gland, which produces oil that birds spread through their plumage when preening. The plumage of waterfowl deprived of uropygial oil becomes brittle and is subject to breakage. | Columba livia; Columbiformes; Preen oil; Ectoparasites; Columbicola columbae; Campanulotes compare; Plumage | 2003 |
561 |
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Wu, Yong-Shi | Explicit solutions of the Bethe ansatz equations for Bloch electrons in a magnetic field | For Bloch electrons in a magnetic field, explicit solutions are obtained at the center of the spectrum for the Bethe ansatz equations of Wiegmann and Zabrodin. When the magnetic flux per plaquette is 1/(Q with Q an odd integer, distribution of the roots of the Bethe ansatz equation is uniform except... | Bloch electron; Magnetic flux | 1994-08 |
562 |
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Capecchi, Mario R. | Expression of a microinjected porcine class I major histocompatibility complex gene in transgenic mice. | A porcine class I major histocompatibility complex (SLA) gene has been introduced into the genome of a C57BL/10 mouse. This transgenic mouse expressed SLA antigen on its cell surfaces and transmitted the gene to offspring, in which the gene is also expressed. Skin grafts of such transgenic mice were... | Genetic Engineering; Graft Rejection; Mice, Inbred C57BL | 1985-05-03 |
563 |
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Mattis, Daniel C. | Extinction of antiferromagnetism by holes in CuO2 | The introduction of a sufficient number of holes into antiferromagnetic planes of Cu02 in La-Cu-O and Y-Ba-Cu-O causes antiferromagnetism to disappear at a critical density xc, beyond which superconductivity occurs. We investigate two competing tendencies, which determine the dependence of xc on the... | Antiferromagnets | 1991-08 |
564 |
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DeTar, Carleton | f B for various actions: approaching the continuum limit with dynamical fermions | We present results for pseudoscalar decay constants of heavy-light mesons using both quenched and Nf = 2 dynamical fermion configurations. A variety of fermion actions is investigated: Wilson, nonperturbative clover, and fat-link clover. For heavy quarks the Fermilab formalism is applied. In the q... | Decay constants; Wilson fermions | 2001-03 |
565 |
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Vardeny, Zeev Valentine | Fabrication and properties of gallium metallic photonic crystals | Gallium metallic photonic crystals with 100% filling factor have been fabricated via infiltration of liquid gallium into opals of 300-nm silica spheres using a novel high pressure-high temperature technique. The electrical resistance of the Ga-opal crystals was measured at temperatures from 10 to 2... | | 2003-10 |
566 |
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Potts, Wayne K. | Fall migration of Golden Eagles in the Wellsville Mountains, Northern Utah, 1976-1979 | Migratory movements of Golden Eagles were investigated in detail as part of a 4-year autumn raptor migration study atop an 8,600-foot ridge in the Wellsville Mountains. In 856 observation hours (161 days) between 6 August and 28 November, 898 Golden Eagles (10% of the oral raptor flight) were counte... | Wellsville Mountains; Golden eagles; Fall migration | 1984 |
567 |
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Miller, Joel Steven | Far-infrared powder spectrum of (N(CH3)3D)(I)(TCNQ) | We present the powder absorption spectrum of (TMA)(I)(TCNQ) in the far-infrared as a function of temperature. Below 160 K new absorption features appear and others increase in intensity. This behaviour supports the electron- neutron-diffraction evidence of a distortion on the TCNQ chains below the f... | Conductivity, Crystals, Electrons | 1983 |
568 |
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Miller, Joel Steven | Far-infrared properties of trimethylammonium iodide tetracyanoquinodimethane | We present the powder absorption spectrum of (TMA) (I)(TCNQ) in the far-infrared as a function of temperature. Below 16 K new absorption features appear and others increase in intensity. This behaviour supports the electron and neutron diffraction evidence of a distortion on the TCNQ chains below... | Trimethylammonium iodide tetracyanoquinodimethane; TCNQ | 1983 |
569 |
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Poulter, Charles Dale | Farnesyl diphosphate synthetase: molecular cloning, sequence, and expression of an essential gene from Saccharomyces cerevisiae | Farnesyl diphosphate (FPP) synthetase is a key enzyme in isoprenoid biosynthesis which supplies C15 precursors for several classes of essential metabolites including sterols, dolichols, and ubiquinones. The structural gene for FPP synthetase was isolated on a 4.5-kilobase EcoRI genomic restriction f... | Genetics; Transferases; Dimethylallyltranstransferase/biosynthesis | 1989-11-15 |
570 |
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Poulter, Charles Dale | Farnesyl pyrophosphate synthetase. Mechanistic studies of the 1'-4 coupling reaction with 2-fluorogeranyl pyrophosphate. | The mechanism of the 1'-4 coupling reaction between isopentenyl pyrophosphate and geranyl pyrophosphate catalyzed by farnesyl pyrophosphate synthetase from porcine liver was studied with the allylic substrate analogue 2-fluorogeranyl pyrophosphate. 2-Fluorogeranyl pyrophosphate is an alternate subst... | Kinetics; Liver; Mass Spectrometry; Organophosphorus Compounds; Protein Binding | 1978-10-25 |
571 |
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Boehme, Christoph | Fast nuclear spin hyperpolarization of phosphorus in silicon | We experimentally demonstrate a method for obtaining nuclear spin hyperpolarization, that is, polarization significantly in excess of that expected at thermal equilibrium. By exploiting a nonequilibrium Overhauser process, driven by white light irradiation, we obtain more than 68% negative nuclear p... | Hyperpolarization; Spin coherence; Electrical readout | 2009-01 |
572 |
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Wu, Yong-Shi | Fast tracking detector with fiber scintillators and a position sensitive photomultiplier | We have studied the properties of a tracking detector composed of 32 fiber scintillators coupled to a multianode photo-multiplier placed in a pion beam at TRIUMF. We measured the efficiency of the detector, as well as its tracking capabilities and double hit resolution. | Fast tracking detector; Fiber scintillators; Position sensitive photomultiplier | 1989-02 |
573 |
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DeTar, Carleton | fB quenched and unquenched | Results for fβ, / fβs, /fD, /fDs , and their ratios are presented. High statistics quenched runs at β = 5.7, 5.85, 6.0, and 6.3, plus a run still in progress at β = 6.52 make possible a preliminary extrapolation to the continuum. The data allows good control of all systematic errors except for q... | Decay constants; Wilson quarks | 1996-03 |
574 |
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Clayton, Dale H. | Feather-busting bacteria | I ONCE HAD A COLLEAGUE who delighted in the aphorism, which he proudly coined himself, "If it's too small to see with the naked eye, it ain't there." Sadly, this view may as well be true for ornithologists who study birds only through unaided eyes, binoculars, or spotting scopes. But birds can also ... | Columba livia; Columbiformes; Ectoparasites; Bacteria; Plumage | 1999 |
575 |
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Vardeny, Zeev Valentine; Symko, Orest George | Femtosecond dynamics of quasi-particles in YBa2Cu3O7-δ superconductor films | We have studied the transient electronic response of YBa2Cu307-δ epitaxialy grown H T c superconductor thin films in the femtosecond time domain, using transient photoinduced reflectivity (AR) with 60 fsec time resolution. For temperatures T>Tc only a bolometric signal was observed with ARrO. For ... | Femtosecond dynamics; YBa2Cu3O7-8; Transient electronic response; Transient optical response | 1991-03 |