Physical Sciences and Mathematics Commons^™

Critical Dynamics Of Nonconserved Ising-Like Systems, K. E. Bassler, Beate Schmittmann

Beate Schmittmann

We show that the dynamical fixed point of Ising-like models, characterized by a single scalar, nonconserved ordering field, is stable near four dimensions with respect to all dynamic perturbations, including those of a nonequilibrium nature.

Kinetics Of Clustering In Traffic Flows, E. Ben-Naim, P. L. Krapivsky, S. Redner

Eli Ben-Naim

We study a simple aggregation model that mimics the clustering of traffic on a one-lane roadway. In this model, each ``car'' moves ballistically at its initial velocity until it overtakes the preceding car or cluster. After this encounter, the incident car assumes the velocity of the cluster which it has just joined. The properties of the initial distribution of velocities in the small velocity limit control the long-time properties of the aggregation process. For an initial velocity distribution with a power-law tail at small velocities, $\pvim$ as $v \to 0$, a simple scaling argument shows that the average cluster size …

Sixth U.S.-Japan Seminar On Polymer Synthesis: Macromolecular Design For Advanced Materials, Otto Vogl, Shiro Kobayashi

Otto Vogl

No abstract provided.

Polymer Institute Slovak Academy Of Sciences Bratislava, Slovakia, Otto Vogl

Otto Vogl

No abstract provided.

64. Tibor Kelen, Otto Vogl

Otto Vogl

No abstract provided.

Aids Epidemiology: A Quantitative Approach, Ron Brookmeyer, Mitchell Gail

Ron Brookmeyer

This comprehensive work confronts the problems that are unique to AIDS research and unites them under a single conceptual framework. It focuses on methods for the design and analysis of epidemiologic studies, the natural history of AIDS and the transmission of HIV, methods for tracking and projecting the course of the epidemic, and statistical issues in therapeutic trials. The various methods of monitoring and forecasting this disease receive comprehensive treatment. These methods include back-calculation, which the authors developed; interpretation of survey data on HIV prevalence; mathematical models for HIV transmission; and approaches that combine different types of epidemiological data. Much …

The Spectral Center Of Gravity Effect And Auditory Filter Bandwidth, Marc Fagelson, Linda M. Thibodeau

Marc A. Fagelson

Low‐Temperature Phase Diagram Of Ybbipt, R. Movshovich, A. Lacerda, Paul C. Canfield, J. D. Thompson, Z. Fisk

Paul C. Canfield

Resistivity measurements are reported on the cubic heavy‐fermion compound YbBiPt at ambient and hydrostatic pressures to ≊19 kbar and in magnetic fields to 1 T. The phase transition at T c =0.4 K is identified by a sharp rise in resistivity. That feature is used to build low‐temperature H‐T and P‐Tphase diagrams. The phase boundary in the H‐T plane follows the weak‐coupling BCS expression remarkably well from T c to T c /4, while small hydrostatic pressure of ≊1 kbar suppresses the low‐temperature phase entirely. These effects of hydrostatic pressure and magnetic field on the phase transition are consistent with …

Mccolm’S Conjecture, Yuri Gurevich, Neil Immerman, Saharon Shelah

Neil Immerman

Gregory McColm conjectured that positive elementary inductions are bounded in a class K of finite structures if every (FO + LFP) formula is equivalent to a first-order formula in K. Here (FO + LFP) is the extension of first-order logic with the least fixed point operator. We disprove the conjecture. Our main results are two model-theoretic constructions, one deterministic and the other randomized, each of which refutes McColm’s conjecture.

Electron Energy Loss In Oxygen Plasmas, G. A. Victor, John C. Raymond, Jane L. Fox

Jane L. Fox

The results of calculations of the energy deposition of energetic electrons in oxygen plasmas are given. In a pure oxygen plasma even with large fractional ionization, much of the electron energy results in the production of additional ionization and excited electronic states. Results are given for separate calculations using theoretical and experimental cross sections for the important O I excitations of ¹S and ¹D because the theoretical and experimental data are not in agreement. These results are useful for understanding the spectra of oxygen-rich supernova remnants.

Using Biodiversity Data To Assess Species--Habitat Relationships In Glacier National Park, Montana, Diane M. Debinski, Peter F. Brussard

Diane M. Debinski

Biodiversity surveys are becoming increasingly popular. However, standard analysis techniques for these data have not yet been developed. This paper explores the use of multivariate ordination techniques for assessing species—habitat relationships using biodiversity data. The research was conducted in Glacier National Park, Montana, and birds and butterflies were chosen as the taxonomic groups of study. Biodiversity assessment sites were established throughout a range of habitats and monitored from 1987 through 1989. Presence/absence sampling over the total number of sampling sites was used to classify species commonness and rarity. Approximately 86% of the historically recorded butterflies and 70% of the historically …

Measurements Of The (E,E’Pπ-) Reaction On Nuclei In The Nucleon Resonance Region, L Elouadrhiri, R A. Miskimen, J Button-Shafer, P Degtyarenko,, Gerald Alvin Peterson, S Shuvalov, K Wang

Gerald Alvin Peterson

Nucleon resonances beyond the Δ(1232) have been observed in complex nuclei. Measurements of the (e,e’pπ-) reaction, at an incident energy of 14.5 GeV with 1.1 GeV

65. Ferenc Tudos, Otto Vogl

Otto Vogl

No abstract provided.

Third Pacific Polymer Conference. Gold Coast - Australia, Otto Vogl, Graeme A. George

Otto Vogl

No abstract provided.

Polymer Science In Australia I. Sydney And Canberra, Otto Vogl, Donald H. Napper

Otto Vogl

No abstract provided.

A Characterization Of Sigma-Symmetrically Porous Symmetrical Cantor Sets, M. Evans, P. Humke, Karen Saxe

Karen Saxe

No abstract provided.

Measurements Of The Electric And Magnetic Form Factors Of The Proton From Q2=1.75 To 8.83 (Gev/C)2, L Andivahis, R S. Hicks, R A. Miskimen, Gerald Alvin Peterson, S Rokni

Gerald Alvin Peterson

The proton elastic form factors GEp(Q2) and GMp(Q2) have been extracted for Q2=1.75 to 8.83 (GeV/c)2 via a Rosenbluth separation to ep elastic cross section measurements in the angular range 13°≤θ≤90°. The Q2 range covered more than doubles that of the existing data. For Q2<4 >(GeV/c)2, where the data overlap with previous measurements, the total uncertainties have been reduced to < 14% in GEp and < 1.5% in GMp. Results for GEp(Q2) are consistent with the dipole fit GD(Q2)=(1+Q2/0.71)-2, while those for GMp(Q2)/μpGD(Q2) decrease smoothly from 1.05 to 0.92. Deviations from form factor scaling are observed up to 20%. The ratio Q2F2/F1 is observed to approach a constant value for Q2>3 (GeV/c)2. Comparisons are made to vector meson dominance, dimensional scaling, QCD sum rule, diquark, and constituent quark models, none of which fully characterize all the new data.

Evidence For A Disk In The Wind Of Hd 93521: Uv Line Profiles From An Axisymmetric Model., Richard Ignace

Richard Ignace

Recently it has been suggested (Massa 1992; Howarth & Reid 1993), from the C IV ultraviolet resonance line profile of HD 93521, that there is a high-speed component in the polar outflow from the star as well as a low-speed component in the equatorial regions. In this paper we present theoretical calculations of the line profiles that would be produced by such a model. We find from Hubble Space Telescope (HST) Goddard High Resolution Spectrograph (GHRS) observations of HD 93521 that the observed C IV profile can be produced if the star has an inclination angle very close to 90 …

Spontaneous Structure Formation In Driven Systems With Two Species: Exact Solutions In A Mean-Field Theory, I. Vilfan, R. K. P. Zia, Beate Schmittmann

Beate Schmittmann

A stochastic lattice gas of particles, subject to an excluded volume constraint and to a uniform external driving field, is investigated. Using a mean-field theory for a system with equal number of oppositely charged particles, exact results are obtained. Focusing on the current-vs-density plot, we propose an explanation for the discontinuous transition found in earlier simulations. A critical value of the drive, below which this transition becomes continuous, is found. These results are supported by a bifurcation analysis, leading to an equation of motion for the amplitude of the soft mode.

Characterization Of Surface Structure And Interactions By Polarization Modulation Fitr And The Quartz Crystal Microbalance, Mark Anderson, Minhui Zhang

Mark R. Anderson

No abstract is currently available.

How Synchronous Are Neogene Marine Plankton Events?, Cinzia Spencer-Cervato, Hans R. Thierstein, David B. Lazarus, Jean-Pierre Beckmann

Cinzia Cervato

An electronic supplement of this material may be obtained on adiskette or Anonymous FTP from KOSMOS.AGU.ORG. (LOGIN toAGU's FTP account using ANONYMOUS as the username andGUEST as the password. Go to the right directory by typing CDAPEND. Type LS to see what files are available. Type GET and thename of the file to get it. Finally, type EXIT to leave the system.)(Paper 94PA01456, How synchronous are Neogene marine planktonevents?, by C. Spencer-Cervato, H. R. Thierstein, D. B. Lazarus, andJ-P Beckmann). Diskette may be ordered from American GeophysicalUnion, 2000 Florida Avenue, N.W., Washington, DC 20009; $15.00.Payment must accompany order. We analyzed …

Xith Symposium On Cationic Polymerization And Related Ionic Processes, Otto Vogl, Ivan M. Panayotov, Christo B. Tsvetanov

Otto Vogl

No abstract provided.

Polymer Science In Australia Ii. Brisbane And Queensland, Otto Vogl, James H. O'Donnell, David J. T. Hill

Otto Vogl

No abstract provided.

Application Of The Binomial Index Of Model Fit: What Research Question Is Being Investigated?, Isadore Newman, John Fraas, Timothy Norfolk

John W. Fraas

No abstract provided.

Studies Toward Understanding The Relationship Between Structure And Function Of Modified Electrodes, Mark Anderson

Mark R. Anderson

No abstract is available at this time.

Commutators As Powers In Free Products Of Groups, Leo Comerford, Charles C. Edmunds, Gerhard Rosenberger

Leo Comerford

The ways in which a nontrivial commutator can be a proper power in a free product of groups are identified

Participation Of The Β Phosphonate Group In Carbocation Formation, Joseph B. Lambert, Robert W. Embridge, Yan Zhao

Yan Zhao

Diethyl (2-(tosyloxy)cyclohexyl)phosphonates have been prepared to test the hypothesis that the strongly electron-withdrawing phosphonate group can stabilize the formation of a /3 carbocation through hyperconjugation. Systems were constructed with the 180" dihedral angle between phosphonate and tosyloxy that is optimal for such participation and with the 60" dihedral angle that minimizes it. Reactions were carried out in aqueous mixtures of ethanol, trifluoroethanol, and hexafluoro-2-propanol. The 60" case had the standard profile for bimolecular reaction with solvent (kB),w ith a slower rate that is sensitive to solvent nucleophilicity. The 180" case had the standard profile for a carbocation pathway (kc), with …

9th Bratislava Conference On Modification Of Thermoplastic Polymers, Otto Vogl, Lyda Matisova-Rychla

Otto Vogl

No abstract provided.

Polymer Science In Australia Iii. Csiro And Other Government Institutions, Otto Vogl, Ezio Rizzardo, Carolyn Morris

Otto Vogl

No abstract provided.

Do Prokaryotes Contain Microtubules?, Lynn Margulis, D. Bermudes, G. Hinkle

Lynn Margulis (1938 - 2011)

In eukaryotic cells, microtubules are 24-nm-diameter tubular structures composed of a class of conserved proteins called tubulin. They are involved in numerous cell functions including ciliary motility, nerve cell elongation, pigment migration, centrosome formation, and chromosome movement. Although cytoplasmic tubules and fibers have been observed in bacteria, some with diameters similar to those of eukaryotes, no homologies to eukaryotic microtubules have been established. Certain groups of bacteria including azotobacters, cyanobacteria, enteric bacteria, and spirochetes have been frequently observed to possess microtubule-like structures, and others, including archaebacteria, have been shown to be sensitive to drugs that inhibit the polymerization of microtubules. …