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Creator | Title | Description | Subject | Date |
| 201 |
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Olivera, Baldomero M. | Poly(ADP-ribosylation) of a DNA topoisomerase | A DNA topoisomerase activity, copurifying with poly(ADP-ribose) synthetase from calf thymus, >95% inhibited if extensive poly(ADP-ribosylation) is allowed to occur. The inhibited DNA topoisomerase, which has drastically different elution properties on hydroxylapatite, can be reactivated by mild alka... | Nicotinic acid; ADP-ribosylation; Turnover cycle; Synthetases | 1983 |
| 202 |
 |
Seger, Jon | Conditional relatedness, recombination, and the chromosome numbers of insects | If two polymorphic loci are out of phase equilibrium, a homozygote at one of these loci is more highly related to its kin, at the other locus, than is an equivalent heterozygote. As a result, selection can favor (1) phenotypic responses to relative heterozygosity, and (2) increased recombination bet... | Coefficients of relatedness; Conditional relatedness | 1983 |
| 203 |
 |
Blair, David F. | Metal centers of cytochrome c oxidase: structures and interactions | Studies directed toward the elucidation of the structures of the metal centers in cytochrome c oxidase are reviewed. Progress towards an understanding of the interactions between these centers and their spatial distributions within the protein will also be presented. Our studies are based primarily... | | 1983 |
| 204 |
 |
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 |
| 205 |
 |
Olivera, Baldomero M.; Gray, William Robert | Conotoxin MI: disulfide bonding and conformational states | The toxic peptide from Conus magus venom (conotoxin MI) is a 14-amino acid peptide (McIntosh, M., Cruz, L. J., Hunkapiller, M. W., Gray, W. R., and Olivera, B. M. (1982) Arch. Biochem. Biophys. 218, 329-334) which inhibits the acetylcholine ceptor. In this work we have confirmed the primary structu... | Conotoxins; Disulfide bonding; Venom; Conus magus | 1983 |
| 206 |
 |
Olivera, Baldomero M. | Bacteriophage Mu DNA replication in vitro | An in vitro system for bacteriophage Mu DNA replication using lysates on cellophane discs is described. Mu replication was monitored by DNA hybridization. Using a thermoinducible Mu Iysogen, 30-50% of all DNA synthesis in vitro was Mu-specific. | Bacteriophage Mu | 1983 |
| 207 |
 |
Vardeny, Zeev Valentine | Picosecond trapping of photocarriers in amorphous silicon | Trapping of photoexcited carriers in the picosecond and subnanosecond time domains was studied by measuring the decay of photoinduced absorption (PA) in a-Si, a-Si:F, a-Si:H, and a-Si:H:F. We found that when the midgap density of states decreases, both the trapping time and its temperature dependenc... | Photocarriers; Amorphous silicon; Picosecond trapping; Photoinduced absorption | 1983 |
| 208 |
 |
Bastiani, Michael | Pathfinding by neuronal growth cones in grasshopper embryos I. Divergent choices made by the growth cones of sibling neurons | We are interested in how the growth cones of identified neurons navigate in the central nervous system of the grasshopper embryo. The behavior of identified growth cones was observed as a function of developmental time by (i) periodically removing embryos from synchronized clutches of eggs and (i... | Neuropil; Axonal; Cell | 1983 |
| 209 |
 |
Mattis, Daniel C. | Application of tridiagonalization to the many-body problem | The problem of a single magnetic, Wolff-model impurity in an otherwise ideal metallic host is investigated using the nonperturbative Lanczos method. Convergence is very rapid. The many-body ground-state energy is investigated and comparisons are made with Tomonaga operator theory and other weak-coup... | Lattice; Electrons; Interaction; Ground-state energy; Tridiagonalization; Magnetic impurity; Nonmagnetic metals | 1983 |
| 210 |
 |
Coley, Phyllis D. | Uprooting and snapping of trees: structural determinants and ecological consequences | The influence of mechanical and architectural properties of trees on growth rates, mortality rates, and relative probabilities of snapping and uprooting were examined on Barro Colorado Island, Republic of Panama. Of 310 fallen trees, 70% snapped, 25% uprooted, and 5% broke off at ground level. Stepw... | Snapping; Uprooting | 1983 |
| 211 |
 |
Miller, Joel Steven; Epstein, Arthur J. | Solitons in nearly commensurate organic charge transfer crystals | X-ray diffuse scattering, magnetic, and conductivity studies of (N-methylphenazinium)x (phenazine)1-x (tetracyanoquinodimethan) [(NMPx(Phen)1-x (TCNQ)] show the formation of defect states for 0.50≤x≤0.54. These results are in agreement with the formation of solitons in a highly correlated quasi-... | Charge-transfer salts | 1983 |
| 212 |
 |
Vardeny, Zeev Valentine | Photoinduced IR active vibrations in trans-(CD)x: a three-mode system | In a recent Letter Blanchet et al.? have extended photoinduced absorption measurements of frYms-polyacetylene to lower energy than obtained before 2 for both isotopes, (CH)x and (CD)X. While in (CE)X three strong ir-active vibrations (IRAV) are photoinduced, only two IRAV were observed in (CD)X, at... | Photoinduced absorption; IR active vibrations | 1983 |
| 213 |
 |
Bastiani, Michael | Loss of axons in the cat optic nerve following fetal unilateral enucleation: an electron microscopic analysis | Between the 48th day of gestation (E-48) and maturity, the number of axons in the cat optic nerve is reduced by approximately 50%. On the basis of an electron microscopic assay, the axon population of the E-48 nerve was estimated to be 328,000. In contrast, estimates from two normal adults were 159,... | Ganglion cell death; Retinofugal projection; Retinal ganglion cell axons | 1983 |
| 214 |
 |
Beckerle, Mary C. | Analysis of the roles of microtubules and actin in erythrophore intracellular motility | The Holocentrus erythrophore, a red pigment cell, represents a model system for the study of organized intracellular transport. We have investigated the possibility that microtubules and actin are integral components of the pigment translocating motility machine. | Actin; Actomyosin; Erythrophore; Pigment | 1983 |
| 215 |
 |
Coley, Phyllis D. | Intraspecific variation in herbivory on two tropical tree species | Levels of herbivory on young and mature leaves were determined for two tree species, Trichilia cipo (Meliaceae) and Cecropia insignis (Moraceae), in a lowland rain forest of Panama. Saplings of both species were studied in light gaps, and in addition, Trichilia was studied in the understory. | Cecropia insignis; Trichilia cipo; Herbivory; Intraspecific variation; Panama; Temporal distribution; Treefall gaps; Tropical forest; Understory | 1983 |
| 216 |
 |
Ailion, David Charles | Floating of the modulation wave and phase pinning in incommensurate Rb2ZnBr4 | Nuclear-magnetic-resonance measurements in incommensurate Rb2ZnBr4 show the existence of regions where the modulation wave is floating. The floating regions coexist with other regions where the modulation wave is static. Impurity phase pinning and a roughening of the modulation wave at higher temper... | Floating; Incommensurate phase; Phason mode; Lattices | 1983 |
| 217 |
 |
Sperry, John S. | Observations on the structure and function of hydathodes in Blechnum lehmanii | The fronds of many ferns in the Polypodiaceae (Ogura, 1972) and Cyatheaceae (Weiler, cited in Lippmann, 1925) possess swollen vein endings associated with specialized adaxial epidermal cells. Their structure is similar in all ferns (Gardiner, 1883; Potonie, 1892; Poirault, 1893; Goebel, 1930; Gutten... | Hydathodes; Blechnum lehmannii; Root pressure; Secretion | 1983 |
| 218 |
 |
Sperry, John S. | Anatomy of the palm Rhapis excelsa, IX. Xylem structure of the leaf insertion | STEMS OF PERENNIAL PLANTS, particularly trees, represent a considerable investment in biomass. Trees can survive even under the most adverse conditions, but only if the hydraulic integrity of the stem is preserved. A very important and vulnerable part of the stem is the xylem. As water is pulled int... | Palm stems; Palm stem anatomy; Palm leaves; Leaf insertion; Vessel network; Vessel-length distribution; Primary vascular stem tissue; Hydraulic architechture; Water column | 1983 |
| 219 |
 |
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 |
| 220 |
 |
Miller, Joel Steven; Epstein, Arthur J. | Noise in highly correlated commensurate charge transfer salts | We present the results of a study of the frequency (f) dependent noise power for commensurate charge transer salts with strong coulomb repulsion. f-1 noise is observed with increasing currents. Excess f-1 noise is measured for samples which were chemically doped to form solitons. Frequency indepe... | Noise power; Charge-transfer salts | 1983 |
| 221 |
 |
Bastiani, Michael | Pathfinding by neuronal growth cones in grasshopper embryos: II. Selective fasciculation onto specific axonal pathways | In the previous paper (Raper, J. A., M. Bastiani, and C. S. Goodman (1983) J. Neurosci. 3: 20-30) we showed that the growth cones of two sibling neurons, the G and C cells, follow the same route in the developing grasshopper neuropil until they reach a stereotypic choice point. Here their growth con... | Neurons; Axons; Neuropil | 1983 |
| 222 |
 |
Bastiani, Michael | Guidance of neuronal growth cones: selective fasciculation in the grasshopper embryo | One of the central questions of developmental neurobiology concerns how the diversity and specificity of individual neurons are generated during embryonic development. One major component of neuronal diversity is the complex axonal morphology of individual neurons, largely generated early in develop... | Neurons; Filopodia; Axon | 1983 |
| 223 |
 |
Mattis, Daniel C. | Effect of spin variables and exciton motion on ground-state properties of the "trion | We solve a quantum three-body problem involving two holes and a single electron ("trion") in a two-band Hubbard model. The particles' spin and the exciton hopping matrix element are all included. We compare the results with those of a previous paper, in which these additional complications were abs... | Three-body problem; Trion; Bond energies | 1983-03 |
| 224 |
 |
Mattis, Daniel C. | Odd-spin-cluster interactions | We consider interactions of Ising spins three at a time, five at a time, etc., as distinguished from the conventional interactions (two at a time). To illustrate, we calculate the exact thermodynamics of three-spin-cluster interactions in one dimension with and without a magnetic field. We find regu... | Ising spins; Binary clusters | 1983-03 |
| 225 |
 |
Mattis, Daniel C. | Nonlinear lattice dynamics in two dimensions | In general, dynamical and quantum-mechanical properties of anharmonic lattices are best expressed in terms of bond variables. A transformation from atomic (site) to bond coordinates is generated in two dimensions, with the help of a number of subsidiary conditions expressed on plaquettes. It is sho... | Phonons; Plaquettes; Harmonic oscillators; Ferromagnets | 1983-04 |
