Physical Sciences and Mathematics Commons^™

The Pulsation Properties Of Procyon A, Brian Chaboyer, P. Demarque, D. B. Guenther

Dartmouth Scholarship

A grid of stellar evolution models for Procyon A has been calculated. These models include the best physics available to us (including the latest opacities and equation of state) and are based on the revised astrometric mass of Girard et al. Models were calculated with helium diffusion and with the combined effects of helium and heavy-element diffusion. Oscillation frequencies for l = 0, 1, 2, and 3 p-modes and the characteristic period spacing for the g-modes were calculated for these models. We find that g-modes are sensitive to model parameters that effect the structure of the core, …

Electro-Optic Response Of Surface-Induced Nematic Order Above The Nematic-Isotropic Phase Transition Temperature, Jong-Hyun Kim, Rolfe G. Petschek, Charles Rosenblatt

Faculty Scholarship

The optical retardation of a liquid crystal above the nematic-isotropic phase transition temperature TNI and subjected to planar alignment conditions at the substrate was investigated in the presence of an electric field applied normal to the substrates. The response was found to exhibit "S"-shaped behavior with electric field, and was larger near TNI than well above TNI. The results were examined in the context of a model that permits both biaxiality and a field-induced tilt of the molecular director. The results suggest that the primary effect of the electric field is to induce biaxiality, and in consequence suppress the order …

Kinematic Analysis Of Spatial Fixed-Axes Pairs Using Configuration Spaces, Ku-Jin Kim, Elisha Sacks, Leo Joskowicz

Department of Computer Science Technical Reports

No abstract provided.

Compression Of Biological Sequences By Greedy Off-Line Textual Subsitution, Alberto Apostolico, Stefano Lonardi

Department of Computer Science Technical Reports

No abstract provided.

Optimal Discovery Of Subword Associations In Strings, Alberto Apostolico, Giorgio Satta

Department of Computer Science Technical Reports

No abstract provided.

Data Organization Issues For Location-Dependent Queries In Mobile Computing, Sunjay Kumar Madria, Bharat Bhargava, Evaggelia Pitoura, Vijay Kumar

Department of Computer Science Technical Reports

No abstract provided.

Performance Evaluation Of Multiple Time Scale Tcp Under Self-Similar Traffic Conditions, Tsunyi Tuan, Kihong Park

Department of Computer Science Technical Reports

No abstract provided.

On Learning Probabilistic Automata, Alberto Apostolico

Department of Computer Science Technical Reports

No abstract provided.

Performance Evaluation Of Cpu Isolation Miechanisms In A Multithreaded Os Kernel, David K.Y. Yau

Department of Computer Science Technical Reports

No abstract provided.

Leveraging Legacy Scientific Software With Mobile Agent Technology, Shanhani Markus, Elias N. Houstis

Department of Computer Science Technical Reports

No abstract provided.

The Prairie Naturalist Volume 31 No.4 December 1999

The Prairie Naturalist

THE FISHES OF THE UPPER MOREAU RIVER ▪ T. M. Loomis, C. R. Berry, Jr., and J. Erickson

DO INTERNAL FIRE LANES AFFECT NEST DEPREDATION RATES IN PRAIRIES? ▪ K. A. Warren and M. R. Ryan

SPECIES COMPOSITION AND TROPHIC STRUCTURE OF INSECT COMMUNITIES IN TEXAS PRAIRIES. ▪ G. N. Cameron and E. H. Bryant

FIDELITY OF MALLARDS TO ARTIFICIAL NESTING STRl!CTURES ▪ T. Yerkes

OBSERVATIONS ON REPRODUCTION IN THREE SPECIES OF BATS ▪ D. W. Sparks, J. R. Choate, and R. J. Winn

EARLIEST SEASONAL RECORD OF REPRODUCTION IN THE HOARY BAT ON THE NORTHERN GREAT PLAINS ▪ T. …

Slow-Binding Inhibition Of The Aminopeptidase From Aeromonas Proteolytica By Peptide Thiols: Synthesis And Spectroscopic Characterization, Kristi M. Huntington, David L. Bienvenue, Yaoming Wei, Brian Bennett, Richard C. Holz, Dehua Pei

Physics Faculty Research and Publications

Peptide-derived thiols of the general structure N-mercaptoacyl-leucyl-p-nitroanilide (1a−c) were synthesized and found to be potent, slow-binding inhibitors of the aminopeptidase from Aeromonas proteolytica (AAP). The overall potencies (K_I*) of these inhibitors against AAP range from 2.5 to 57 nM exceeding that of the natural product bestatin and approaching that of amastatin. The corresponding alcohols (2a−b) are simple competitive inhibitors of much lower potencies (K_I = 23 and 360 μM). These data suggest that the free thiols are involved in the formation of the E·I …

Mpeg-4 Systems And Applications, Hari Kalva, Lai-Tee Cheok, Alexandros Eleftheriadis

Research Collection School Of Computing and Information Systems

MPEG-4, under the auspices of the ISO, is specifying tools to enable object-based audio-visual presentations [3]. These include tools to encode individual objects, compose presentations with objects, store these object-based presentations and access these presentations in a distributed manner over networks. The main distinguishing feature of object-based audio-visual presentations is the scene composition at the user terminal. The objects that are part of a scene are composed and displayed at the user end as opposed to encoding the composed scenes as is done in the case of MPEG-2. Such object-based representation and presentation has several benefits including compression efficiency and …

Zbroker: A Query Routing Broker For Z39.50 Databases, Yong Lin, Jian Xu, Ee Peng Lim, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

A query routing broker is a software agent that determines from a large set of accessing information sources the ones most relevant to a user's information need. As the number of information sources on the Internet increases dramatically, future users will have to rely on query routing brokers to decide a small number of information sources to query without incurring too much query processing overheads. In this paper, we describe a query routing broker known as ZBroker developed for bibliographic database servers that support the Z39.50 protocol. ZBroker samples the content of each bibliographic database by using training queries and …

Coordinate Realizations Of Deformed Lie Algebras With Three Generator, Ranabir Dutt, Asim Gangopadhyaya, C. Rasinariu, Uday P. Sukhatne

Physics: Faculty Publications and Other Works

Differential realizations in coordinate space for deformed Lie algebras with three generators are obtained using bosonic creation and annihilation operators satisfying Heisenberg commutation relations. The unified treatment presented here contains as special cases all previously given coordinate realizations of so(2,1), so(3), and their deformations. Applications to physical problems involving eigenvalue determination in nonrelativistic quantum mechanics are discussed.

Intensity Dependence Of Plateau Structures In Laser-Assisted X-Ray–Atom Scattering Processes, Dejan B. Miloševic, Anthony F. Starace

Anthony F. Starace Publications

The dependence on laser intensity of recently discovered plateau structures in laser-assisted x-ray–atom scattering, both with and without a static electric field present, is analyzed. Using the “three-step” model and the strong-field approximation we demonstrate a connection between laser-assisted, x-ray–atom scattering and high-order harmonic generation: For high laser-field intensities without a static field present, both processes have plateaus whose energies extend to the cutoff value 3.17U_p, where U_p is the ponderomotive potential energy. For x-ray–atom scattering in the presence of a static electric field we show that at high laser-field intensities two plateaus appear: One is …

Resonant Enhancement Of Relativistic Electron Fluxes During Geomagnetically Active Periods, I Roth, M Temerin, M K. Hudson

Dartmouth Scholarship

The strong increase in the ̄ux of relativistic electrons during the recovery phase of magnetic storms and during other active periods is investigated with the help of Hamiltonian formalism and simulations of test electrons which interact with whistler waves. The intensity of the whistler waves is enhanced signi®cantly due to injection of 10±100 keV electrons during the substorm. Electrons which drift in the gradient and curvature of the magnetic ®eld generate the rising tones of VLF whistler chorus. The seed population of relativ- istic electrons which bounce along the inhomogeneous magnetic ®eld, interacts resonantly with the whistler waves. Whistler wave …

Comment On "Ideal Capacitor Circuits And Energy Conservation" By K. Mita And M. Boufaida [Am. J. Phys. 67 (8), 737-739 (1999)], Asim Gangopadhyaya, Jeffrey Mallow

Physics: Faculty Publications and Other Works

No abstract provided.

Performance Of The Cleo Iii Lif-Tea Ring Imaging Cherenkov Detector In A High Energy Muon Beam, Raymond Mountain, Marina Artuso, R. Ayad, F. Azfar

Physics - All Scholarship

The CLEO III Ring Imaging Cherenkov detector uses LiF radiators to generate Cherenkov photons which are then detected by proportional wire chambers using a mixture of CH$_4$ and TEA gases. The first two photon detector modules which were constructed, were taken to Fermilab and tested in a beam dump that provided high momentum muons. We report on results using both plane and "sawtooth" shaped radiators. Specifically, we discuss the number of photoelectrons observed per ring and the angular resolution. The particle separation ability is shown to be sufficient for the physics of CLEO III.

Search For The Flavor-Changing Neutral Current Decays B+→ Μ+Μ-K+ And B0→ Μ+Μ-K*0, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report on a search for the flavor-changing neutral current decays B⁺→ μ⁺μ^-K⁺ and i>B⁰→ μ⁺μ^-K^*0 using 88 pb^-1 of data from p̅p collisions at √s =1.8 TeV, collected with the Collider Detector at Fermilab. Finding no evidence for these decays, we set upper limits on the branching fractions Ɓ(B⁺→ μ⁺μ^-K⁺) < 5.2 X 10^-6 and Ɓ(B⁺→ μ⁺μ^-K^*0) -6 at the 90% confidence level.

Computational Study Of Molecular Hydrogen In Zeolite Na-A. I. Potential Energy Surfaces And Thermodynamic Separation Factors For Ortho And Para Hydrogen, Cherry-Rose K. Anderson , '95, D. F. Coker, J. Eckert, Amy Lisa Graves

Physics & Astronomy Faculty Works

We simulate H-2 adsorbed within zeolite Na-A. We use a block Lanczos procedure to generate the first several (9) rotational eigenstates of the molecule, which is modeled as a rigid, quantum rotor with an anisotropic polarizability and quadrupole moment. The rotor interacts with Na cations and O anions; interaction parameters are chosen semiempirically and the truncation of electrostatic fields is handled with a switching function. A Monte Carlo proceedure is used to sample a set of states based on the canonical distribution. Potential energy surfaces, favorable adsorbtion sites, and distributions of barriers to rotation are analyzed. Separation factors for ortho-parahydrogen …

Fiberglast: A Scintillating Fiber Approach To The Glast Mission, Geoffrey N. Pendleton, W Robert Binns, Martin W. Israel, P L. Hink, M L. Cherry, W Paciesas, R M. Kippen, Robert S. Mallozzi, Thomas A. Parnell, Gerald J. Fishman, O T. Tumer, Mark J. Christl, Robert B. Wilson, J Buckley, Georgia A. Richardson, Surasak Phengchamnan, Keith R. Rielage, Gerald Karr, Donald B. Wallace, James M. Ryan, Mark L. Mcconnell, John R. Macri

Space Science Center

FiberGLAST is a scintillating fiber gamma-ray detector designed for the GLAST mission. The system described below provides superior effective area and field of view for modest cost and risk. An overview of the FiberGLAST instrument is presented, as well as a more detailed description of the principle elements of the primary detector volume. The triggering and readout electronics are described, and Monte Carlo Simulations of the instrument performance are presented.

Beam Test Results For The Fiberglast Instrument, Robert S. Mallozzi, R M. Kippen, Geoffrey N. Pendleton, W Paciesas, Georgia A. Richardson, Surasak Phengchamnan, Gerald Karr, Donald B. Wallace, Gerald J. Fishman, Thomas A. Parnell, Robert B. Wilson, Mark J. Christl, W Robert Binns, P L. Hink, Martin W. Israel, Keith R. Rielage, John W. Epstein, Paul F. Dowkontt, J Buckley, James M. Ryan, John R. Macri, Mark L. Mcconnell, O T. Tumer, M L. Cherry, T G. Guzik, J G. Stacy, S C. Kappadath, Muzaffer Atac, Katsushi Arisaka, David B. Cline, Yuriy Pischalnikov

Space Science Center

The FiberGLAST scintillating fiber telescope is a large-area instrument concept for NASA's GLAST program. The detector is designed for high-energy gamma-ray astronomy, and uses plastic scintillating fibers to combine a photon pair tracking telescope and a calorimeter into a single instrument. A small prototype detector has been tested with high energy photons at the Thomas Jefferson National Accelerator Facility. We report on the result of this beam test, including scintillating fiber performance, photon track reconstruction, angular resolution, and detector efficiency.

Coded-Aperture X-Ray/Gamma-Ray Telescope For Arc-Minute Localization Of Gamma-Ray Bursts, M L. Cherry, P P. Altice, D L. Band, J Buckley, T G. Guzik, P L. Hink, S C. Kappadath, John R. Macri, J L. Matteson, Mark L. Mcconnell, Terence J. O'Neill, James M. Ryan, K R. Slavis, J G. Stacy, Allen Zych

Space Science Center

MARGIE will be a large-area, wide field-of-view, hard x- ray/gamma-ray imaging telescope capable of providing accurate positions for faint gamma-ray bursts in near-real- time and of performing a sensitive survey of both steady and transient cosmic sources. The instrument is designed to image faint bursts at the low-intensity end of the log N - log S distribution. MARGIE was recently selected by NASA for a mission-concept study for an Ultra Long Duration Balloon flight. We describe a program to develop an instrument based on the new detector technology of either cadmium zinc telluride room-temperature semiconductors or pixelated cesium iodide scintillators …

Recent Progress In The Development Of A Solar Neutron Tracking Device (Sontrac), James M. Ryan, Wenhui Li, John R. Macri, Mark L. Mcconnell, Carlos Castaneda, Juan L. Romero

Space Science Center

We report the results of recent calibration data analysis of a prototype scintillating fiber tracking detector system designed to perform imaging, spectroscopy and particle identification on 20 to 250 MeV neutrons and protons. We present the neutron imaging concept and briefly review the detection principle and the prototype description. The prototype detector system records ionization track data on an event-by-event basis allowing event selection criteria to be used in the off-line analysis. Images of acrylic phantoms from the analysis of recent proton beam calibrations are presented as demonstrations of the particle identification, imaging and energy measurement capabilities. The measured position …

Development And Testing Of A Fiber/Multianode Photomultiplier System For Use On Fiberglast, Keith R. Rielage, Katsushi Arisaka, Muzaffer Atac, W Robert Binns, J Buckley, M L. Cherry, Mark J. Christl, David B. Cline, Paul F. Dowkontt, John W. Epstein, Gerald J. Fishman, T G. Guzik, P L. Hink, Martin H. Israel, S C. Kappadath, Gerald Karr, R M. Kippen, Daniel Leopold, Mark L. Mcconnell, John R. Macri, Robert S. Mallozzi, W Paciesas, Thomas A. Parnell, Geoffrey N. Pendleton, Surasak Phengchamnan, Yuriy Pischalnikov, Georgia A. Richardson, James M. Ryan, J G. Stacy, O T. Tumer, Gerald J. Vissor, Donald B. Wallace, Robert B. Wilson

Space Science Center

A scintillating fiber detector is currently being studied for the NASA Gamma-Ray Large Area Space Telescope (GLAST) mission. This detector utilizes modules composed of a thin converter sheet followed by an x, y plane of scintillating fibers to examine the shower of particles created by high energy gamma-rays interacting in the converter material. The detector is composed of a tracker with 90 such modular planes and a calorimeter with 36 planes. The two major component of this detector are the scintillating fibers and their associated photodetectors. Here we present current status of development and test result of both of these. …

Energy And Position Resolution Of A Cdznte Gamma-Ray Detector With Orthogonal Coplanar Anodes, O Tousignant, L A. Hamel, Pierre C. Dufour, F Joly, John R. Macri, Mark L. Mcconnell, James M. Ryan, V T. Jordanov

Space Science Center

We report on the simulation, construction and performance of prototype CZT imaging detectors employing orthogonal coplanar anodes. These detectors employ a novel electrode geometry with non-collecting anode strips in 1D and collecting anode pixels, interconnected in rows, in the orthogonal dimensions. These detectors retain the spectroscopic and detection efficiency advantages of single carried charge sensing devices as well as the principal advantage of conventional strip detectors with orthogonal anode and cathode strips, i.e. an N X N array of imagin pixels are realized with only 2N electronic channels. Charge signals induced on the various electrodes of a prototype detector with …

Inflation And Preheating In Nonoscillatory Models, Gary Felder, Lev Kofman, Andrei Linde

Physics: Faculty Publications

We study inflationary models in which the effective potential of the inflaton field does not have a minimum, but rather gradually decreases at large φ. In such models the inflaton field does not oscillate after inflation, and its effective mass becomes vanishingly small, so the standard theory of reheating based on the decay of the oscillating inflaton field does not apply. For a long time the only mechanism of reheating in such non-oscillatory (NO) models was based on gravitational particle production in an expanding universe. This mechanism is very inefficient. We will show that it may lead to cosmological problems …

Search For A Technicolor ΩT Particle In Events With A Photon And A B-Quark Jet At Fermilab, F. Abe, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

If the technicolor ω_T particle exists, a likely decay mode is ω_T→ γπ_T , followed by π_T → bb̅, yielding the signature γbb̅. We have searched 85 pb^-1 of data collected by the CDF experiment at the Fermilab Tevatron for events with a photon and two jets, where one of the jets must contain a secondary vertex implying the presence of a b quark. We find no excess of events above standard model expectations. We express the result as an exclusion region in the M_ωT -M_{πT …}

Reactive Nitrogen Budget During The Nasa Sonex Mission, R. Talbot, Jack E. Dibb, Eric Scheuer, Y Kondo, M Koike, H B. Singh, L Salas, F Fukui, J O. Ballenthin, R F. Meads, T M. Miller, D E. Hunton, A A. Viggiano, D R. Blake, N J. Blake, Elliot Atlas, F Flocke, D J. Jacob, L Jaegle

Earth Sciences

The SASS Ozone and Nitrogen Oxides Experiment (SONEX) over the North Atlantic during October/November 1997 offered an excellent opportunity to examine the budget of reactive nitrogen in the upper troposphere (8–12 km altitude). The median measured total reactive nitrogen (NO_y) mixing ratio was 425 parts per trillion by volume (pptv). A data set merged to the HNO₃ measurement time resolution was used to calculate NO_y (NO_y sum) by summing the reactive nitrogen species (a combination of measured plus modeled results) and comparing it to measured NO_y (NO_y meas.). Comparisons were done for tropospheric …