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Filters: Date: "1993" School Or College: "College of Science" Collection: ir_uspace
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CreatorTitleDescriptionSubjectDate
1 Ailion, David Charles31P NMR spin-lattice relaxation: structural glass dynamics in Rb1-x(ND4)xD2PO4We performed 3 1P NMR measurements of the temperature-dependent spin-lattice relaxation time in several mixed single crystals of Rbi_x(ND4 ) xD2P04 [DRADP] having different ammonium concentration x (x =0.22, 0.44, 0.78) as well as in three pure single crystals (ND4)D2P04 [DADP], (NH4)H2P04 [ADP], an...NMR; Spin-lattice; Relaxation; Crystals; Glass; Spin-glass1993
2 Miller, Joel Steven; Epstein, Arthur J.Anomalous charge transport phenomena in the molecular-based magnet V(TCNE)x.y(solvent)We present charge transport studies on recently developed molecular-based magnets V(TCNE)x. y(solvent) (TCNE= tetracyanoethylene) which show local magnetic ordering at temperatures, T, as high as 400 K. V(TCNE), .y(solvent) prepared from the solvent CH2Cl2 has o(300 K) - 10-3 S/cm, and that prepar...Frequency; Conductivity; Spin1993
3 Davidson, Diane W.Ant-plant symbioses in Africa and the neotropics : history, biogeography and diversitySymbiotic ant-plant relationships afford an excellent opportunity to analyze the effects of both historical and ecological factors on the evolution of mutualisms. Occurring in tropical forests throughout the world, all myrmecophytic plants provide food and permanent housing to ants; the ants, in t...Ant-plant symbiosis; Africa; Neotropics; Myrmecophytes; Plant-ants1993
4 Bastiani, MichaelCell-cell interactions during the migration of an identified commissural growth cone in the embryonic grasshopperOne of the fascicles of the posterior commissure of the embryonic grasshopper is pioneered by an individually identifiable neuron named Q1. Q1 initially grows along a longitudinal pathway established by another pioneer neuron, MPl, and then crosses to the midline, where it meets and fasciculates wi...Commissure; Pathfinding; Filopodia1993
5 Coley, Phyllis D.; Kursar, Thomas A.Colonization of tropical rain forest leaves by epiphylls: effects of site and host plant leaf lifetimeIn humid tropical regions, leaves are frequently colonized by epiphylls (Richards 1954, Pocs 1978, 1982). Lichens and liverworts usually dominate, although mosses, algae, and cyanobacteria can also occur (Winkler 1971, Smith 1982). The interactions between epiphylls and host leaves have not been wel...Tropical forest; Epiphylls; Panama; Hybanthus prunifolius; Light interception1993
6 Clayton, Dale H.Common grackle anting with lime fruit and its effect on ectoparasitesAnting is stereotyped behavior in which birds ex- pose themselves to fluid-secreting ants or other pun- gent substances. During "active" anting a bird crush- es an ant in the bill and rubs it frenetically through its plumage (Rothschild and Clay 1952). During "passive" anting a bird entices ants to ...Quiscalus quiscala; Columbicola columbae; Anting; Ectoparasites1993
7 Miller, Joel Steven; Epstein, Arthur J.Complex ac susceptibility studies of the disordered molecular based magnets V(TCNE)x: role of spinless solventThe effect of different spinless solvents on the magnetism of V(TCNE)x . y(solvent) (TCNE= tetracyanoethylene) is studied by temperature (T) dependent ac susceptibility above 2.3 K. Though V(TCNE)x.y(CH2Cl2) has a critical temperature Tc -400 K, for V(TCNEx.y(C4H8O), Tc -205 K and the coercive field...Magnetization; Spin; Temperature1993
8 Olivera, Baldomero M.; McIntosh, J. MichaelConus peptides as tools for the neuroscientistRecombinant DNA technology has had a powerful impact on understanding receptors and ion channels, the key components in the nervous system that are involved in intercellular communication. Cloning genes encoding these proteins has revealed that for every receptor and ion channel type, multiple molec...Conus peptides; Conotoxins1993
9 Bohs, Lynn A.Cyphomandra (Solanaceae)Cyphomandra betacea (Cavanilles) Sendtner Syn. Cyphomandra crassifotia (Ortega) Kuntze, Solanum betacea Cavanilles, Solanwn crassifolium Ortega. Ref. FB 13(5B/1) 1962: 12; Bohs, 1986: 170. Cultivated tree. Andean II. 1000-3000 m. Voucher: Nunez et al. 8257 (MO!) Depts.: AM, CU, HU, SMCyphomandra; Solanum1993
10 Miller, Joel Steven; Epstein, Arthur J.Decamethylchromocenium tetracyanoethenide, + [Cr(C5Me5)2]:.+[TCNE].-: a molecular ferromagnet with Tc=3.65 KThe electron-transfer salt 4[Cr(C5Me5)2] + [TCNE].-(TCNE = tetracyanoethylene) has been prepared and structurally characterized by single-crystal X-ray diffraction. It possesses a solid-state motif of parallel 1D chains of alternating radical cations and anions similar to, but not isostructural to, ...Magnetic; Electron transfer; Coupling1993
11 Morse, Michael DavidElectron spin resonance investigation of Sc?+ in neon matrices and assignment of its ground electronic state as X ???. comparison with theoretical calculationsThe discandium radical cation, Sc+2 , has been isolated in neon matrices at 4 K and studied by electron spin resonance (ESR) spectroscopy and theoretical methods. It was produced by the x-irradiation of neon matrix samples containing neutral ScZ which was formed by trapping the products generated fr...1993
12 Beckerle, Mary C.Evidence for the selective association of a subpopulation of GPIIb-IIIa with the actin cytoskeletons of thrombin-activated plateletsActivation of blood platelets triggers a series of responses leading to the formation and retraction of blood clots. Among these responses is the establishment of integrin-mediated transmembrane connections between extracellular matrix components and the actin cytoskeleton of the platelet.Actin; GPIIb-IIIa1993
13 Davidson, Diane W.Evolutionary ecology of symbiotic ant-plant relationshipsAbstract.--A tabular survey of ant-plant symbioses worldwide summarizes aspects of the evolutionary ecology of these associations. Remarkable similarities between ant-plant symbioses in disjunct tropical regions result from convergent and parallel evolution of similarly preadapted ants and plants. ...Symbioses; Evolution; Taxonomic1993
14 Miller, Joel Steven; Epstein, Arthur J.Ferromagnetic behavior of decamethylchromocenium tetracyanoethenide, [CrCp*2][TCNE]Studies on the magnetic properties of decamethylchromocenium tetracyanoethanide, [CrCp*2][TCNE] are reported herein. Near-zero field (H= 150 mG) data indicates a ferromagnetic transition with T(c)=3.65 K. The temperature dependence below T(c) can be fit to a mean-field result M=M(o)(1 - T(o))(1/2)...Magnetic; Magnetization; Transition1993
15 Bastiani, MichaelGrowth cone dynamics during the migration of an identified commissural growth coneWe have used time-lapse video microscopy to study the behavior of a neuron, 01, that pioneers the posterior commissure of the embryonic grasshopper. Our goal is to use time-lapse video as a tool to acquire a precise picture of normal development over time, and thereby identify stereotypic activities...Time-lapse video; Commissure; Grasshopper; Pathfinding; Filopodia; Confocal microscopy; Adhesion1993
16 Morse, Michael DavidLaser vaporization generation of the SiB and SiAi radicals for matrix isolation electron spin resonance studies: comparison with theoretical calculations and assignment of their electronic ground states as X ??The first experimental spectroscopic study of the SiB and SiAl diatomic radicals is reported. Electron spin resonance results indicate that both molecules have X 4? ground electronic states, in agreement with earlier theoretical calculations. The SIB and SiAl radicals were generated in neon matrices...1993
17 Olivera, Baldomero M.; ; McIntosh, J. MichaelLocalization of [125I] ω-conotoxin GVIA binding in human hippocampus and cerebellumTHE peptide toxin ω-conotoxin GVIA (ω-CgTx) has been shown to be a high affinity ligand for N-type calcium channels in the brain. We have employed [125I]ω-CgTx to localize N-type channels in human hippocampus and cerebellum using autoradiography. Ten micron thick slidemounted tissue sections of...Conotoxins; Peptide toxins1993
18 Miller, Joel StevenMagnetization and static scaling of high-Tc disordered molecular-based magnet V(tetracyanoethylene)x¢y(CH3CN) with x ~ 1.5 and y ~ 2)We report field (H) and temperature (T) -dependent magnetization (M) of a member of the new class of high-Tc molecular-based magnets V(tetracyanoethylene)x .y(solvent) with Tc in an accessible range (solvent =CH3CN). The M (H) at low T saturates slowly with increasing H. The random magnetic anisotro...Temperature; Magnetic; Random1993
19 Williams, Clayton C.Mapping of mobile charges on insulator surfaces with the electrostatic force microscopeMigration of surface ions in lateral fields on insulator surfaces may modify the electrical characteristics of underlying semiconductor structures causing device instabilities. A high sensitivity electrostatic force microscope is used to image the movement and spatial distribution of surface ions on...Insulator surfaces; Surface ions; Electrostatic force microscope1993
20 Adler, Frederick R.Migration alone can produce persistence of host-parasitoid modelsIt has long been recognized that the unstable equilibrium of a single-patch predator-prey model cannot be stabilized by diffusive coupling with identical patches, since the coupled system acts exactly like the single-patch system if the patches are synchronized (Maynard Smith 1974; Allen 1975; Reeve...Heterogeneity; Nicholson-Bailey; migration rates1993
21 Wu, Yong-ShiOn the Kadomtsev-Petviashvili hierarchy, Ŵ∞ algebra, and conformal SL(2,R)/U(1) model. II. The quantum caseThis article is devoted to constructing a quantum version of the famous Kadomtsev-Petviashvili (KP) hierarchy by deforming its second Hamiltonian structure, namely, the nonlinear W, algebra. This is achieved bx quantizing the conformal noncompact SL(2,R) k/ U(1) coset model, in which W, appears as ...Kadomtsev-Petviashvili hierarchy; Quantum charges; W-algebras1993
22 Morse, Michael DavidPhotodissociation measurements of bond dissociation energies: Ti?+, V?+, Co?+, and Co?+The bond dissociation energies of Ti2+, V+2 , Co+2, and Co: have been measured from the sudden onset of predissociation in the photodissociation spectra of these molecules, yielding values of D?(Ti+2)=2.435+0.002 eV, D?(V+2)=3.140?0.002 eV, D?(Co+2)=2.7651?0.001 eV, and D?(Co+3)=2.086?0.002 eV. Thes...1993
23 Miller, Joel StevenPressure dependence of magnetic ordering temperature for decamethylferrocenium tetracyanoethenideIt has been demonstrated that the linear-chain charge-transfer salt, decamethylferrocenium tetracyanoethanide (DMeFc) (TCNE), is a ferromagnet with a transition temperature of -4.8 K. This low-temperature 3D ordering has been attributed to a strong intrachain and a weak interchain interaction. To...Ferromagnetic; Transition; Antiferromagnetic1993
24 Ehleringer, James R.Seedling size and survival for Chrysothamnus nauseosusSeedling size and survival in relation to summer drought were examined for Chrysothamnus nauseosus growing under field and greenhouse conditions. In the field, summer survival rates were less than 2% annually for the three years monitored. The effect of initial seedling height on subsequent survival...Chrysothamnus nauseosus; Seedling size; Seedling survival1993
25 Morse, Michael DavidSpectroscopic analysis of jet-cooled AICuDiatomic AlCu has been interrogated using resonant two-photon ionization spectroscopy in a supersonic expansion of helium. The ground state is shown to be X l?+, deriving from the 3&3dgd configuration, in agreement with theoretical predictions. The closed-shell nature of this molecule results in a l...1993
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