Physical Sciences and Mathematics Commons^™

An Explanation Of Observed Trends In The X-Ray Emission From Single Wolf-Rayet Stars., R. Ignace, L. M. Oskinova

Richard Ignace

The O and early B star winds show empirical correlations between X-ray (L_x) and Bolometric (L_Bol) luminosity as well as wind properties such as wind momentum and wind kinetic energy. Wolf-Rayet stars do not. We discuss scaling relations to qualitatively explain this lack of correlation among the WR winds and to quantitatively reproduce the observed ratio of X-ray luminosities between the N-rich WN types and C-rich WC types. If (a) the filling factor of hot X-ray emitting gas varies as (M⊙/v_\infty)(-1) for stars of different mass loss and terminal speed and (b) the ambient Wolf-Rayet wind component is optically thick …

The Hanle Effect As A Diagnostic Of Magnetic Fields In Stellar Envelopes Ii. Some Theoretical Results For Resolved Line Profiles., R. Ignace, J. P. Cassinelli, K. H. Nordsieck

Richard Ignace

A magnetic field diagnostic of stellar winds that uses the Hanle effect is discussed. This diagnostic pertains to the modification of resonance-line-scattering polarization in the presence of magnetic fields. The case for resolved polarized profiles of optically thin emission lines is considered, and some analytic results for an expanding equatorial disk are derived. Numerical results for a dipole magnetic field embedded in a spherical outflow are also presented. Although the considerations are somewhat simplified, the primary conclusion is that the modification or creation of line profile polarization by the Hanle effect can be used to discriminate between different magnetic field …

Scattering Polarization Due To Light Source Anisotropy I. Large Spherical Envelope., M. B. Al-Malki, J. F. L. Simmons, R. Ignace, J. C. Brown, D. Clarke

Richard Ignace

Expressions are developed for the flux and polarization of radiation scattered by a spherically symmetric envelope for a central point stellar light source that radiates anisotropically. These are obtained in terms of the components of the spherical harmonics of the flux anisotropy from the source. Such anisotropy can arise from stellar spots, or from distortion of the star through rotation, pulsation, or magnetic effects. Explicit expressions for the Stokes parameters are obtained in the case of an ellipsoidal star of uniform surface brightness. It is thus shown that even when the scattering envelope is spherical, observationally significant polarization can arise …

Probabilistic Crowding: Deterministic Crowding With Probabilistic Replacement, Ole J. Mengshoel, David E. Goldberg

Ole J Mengshoel

This paper presents a novel niching algorithm, probabilistic crowding. Like its predecessor deterministic crowding, probabilistic crowding is fast, simple, and requires no parameters beyond that of the classical GA. In probabilistic crowding, subpopulations are maintained reliably, and we analyze and predict how this maintenance takes place.

This paper also identifies probabilistic crowding as a member of a family of algorithms, which we call integrated tournament algorithms. Integrated tournament algorithms also include deterministic crowding, restricted tournament selection, elitist recombination, parallel recombinative simulated annealing, the Metropolis algorithm, and simulated annealing.

Phd Thesis (Doctorat De Spécialité): Université De Ouagadougou, 1999. Dr. Mamoudou H. Dicko. Purification Et Propriétés Physico-Chimiques Des Enzymes De Curculigo Pilosa, Gladiolus Klattianus Et Boscia Senegalensis Catalysant L'Hydrolyse Des Polysaccharides (Amidon Et Béta-Glucanes), Mamoudou H. Dicko Prof.

Pr. Mamoudou H. DICKO, PhD

The objective of this study was the research of novel and inexpensive sources of polysaccharides degrading enzymes such as amylases and glucanases from local plants in order to justify their biotechnological applications. The isolation of two l3-amylases and an endo-1,3-ß-D-glucanase was reached using common protein purification methods such as buffer extraction, ammonium sulfate fractionation, ionexchange and gel filtration chromatographies. The methods used were simple and easily reproducible, suggesting the possibilfty of large-scale production. ln the crude extract of Curculigo pilosa tuber, only ß-amylase was detected as starch degrading enzyme and its activity was approximately 282 Uig of fresh material. The …

Reference Materials For Calorimetry And Differential Thermal Analysis, R. Sabbah, An Xu-Wu, J.S. Chickos, M.L.Planas Leitão, M.V. Roux, L.A. Torres

James Chickos

No abstract provided.

Voltammetry Of Metallofullerenes And Higher Fullerenes, Mark Anderson, Harry Dorn, Steven Stevenson, Susanne Dana

Mark R. Anderson

No abstract is currently available.

“Every Breath You Take... ”: The Demographics Of Toxic Air Releases In Southern California, James Sadd, Manuel Pastor, J. Boer, Lori Snyder

James Sadd

In this article, the authors investigate the relationship between ethnicity and potential environmental hazards in the metropolitan Los Angeles area. Using a variety of techniques, including geographic information systems (GIS) mapping, univariate comparisons, and logit, ordered logit, and tobit regression analysis, the authors find that, even controlling for other factors such as income and the extent of manufacturing employment and land use, minority residents tend to be disproportionately located in neighborhoods surrounding toxic air emissions. The results generally support the propositions of the proponents of “environmental justice”; in the conclusion, they consider what this might mean for urban land use …

Statistics For Logisticians – Back To Basics, Caroline Lubert

Caroline P Lubert

No abstract provided.

The Correlation Of Physical Properties Of Organic Molecules With Computed Molecular Surface Areas., Robert Mebane, Shannon Schanley, Thomas Rybolt, Chrystal Bruce

Chrystal D. Bruce

The objective of this paper is to show that a student's understanding of molecular properties can be enhanced with the study of molecular surface areas obtained from readily available molecular modeling software.

Radiocarbon Chronology And Δ13c Analysis Of Mid-To Late-Holocene Aeolian Environments, Guadalupe Mountains National Park, Texas, Usa, David Wilkins, Donald Currey

David E. Wilkins

The Red Dunes of Guadalupe Mountains National Park are quartzose sand sheets and dunes stabilized by sparse plant cover. Stratigraphy, radiocarbon dating, and δ13C analysis were examined in two of the larger arroyos for correlating evidence of aeolian deposition, which in this basin is taken as an indication of arid conditions. Four quartz-sand lithostratigraphic units, representing intervals of aeolian activity, are identified. Radiocarbon dates provide constraint on the timing of the three youngest quartz-sand units. A mid-Holocene aeolian interval, represented by a single radiocarbon date of 6350± 70 BP, is interpreted as transitional to an altithermal regime. A neopluvial period, …

Discontinuities In Recurrent Neural Networks, R. Gavaldà, Hava Siegelmann

Hava Siegelmann

This article studies the computational power of various discontinuous real computational models that are based on the classical analog recurrent neural network (ARNN). This ARNN consists of finite number of neurons; each neuron computes a polynomial net function and a sigmoid-like continuous activation function. We introduce arithmetic networks as ARNN augmented with a few simple discontinuous (e.g., threshold or zero test) neurons. We argue that even with weights restricted to polynomial time computable reals, arithmetic networks are able to compute arbitrarily complex recursive functions. We identify many types of neural networks that are at least as powerful as arithmetic nets, …

The Discovery-Oriented Approach To Organic Chemistry 1. Nitration Of Unknown Organic Compounds. An Exercise In 1H Nmr And 13C Nmr Spectroscopy For Sophomore Organic Laboratories, Ram S. Mohan, Sonia R. Mcelveen, Kostas Gavardinas, Jean A. Stamberger

Ram S. Mohan

The Spectral Function Of Composites: The Inverse Problem, Anthony Day, M. Thorpe

Anthony Roy Day

No abstract provided.

Jual Obat Aborsi Samarinda 082244058007 Obat Penggugur Kandungan, Arin Najwa, Obat Aborsi Asli Manjur Serta Tuntas

arin najwa

Mil-Std-188-125-2, High-Altitude Emp Protection For Transportable Systems

George H Baker

This standard establishes minimum requirements and design objectives for high-altitude electromagnetic pulse (HEMP) hardening of transportable1 ground-based systems that perform critical, time-urgent command, control, communications, computer, and intelligence (C4I) missions. Systems required to fully comply with the provisions of the standard will be designated by the Joint Chiefs of Staff, a Military Department Headquarters, or a Major Command.

The standard prescribes minimum performance requirements for low-risk protection from mission-aborting damage or upset due to HEMP threat environments. The standard also addresses minimum testing requirements for demonstrating that prescribed performance has been achieved and for verifying that the installed protection measures …

Jual Obat Aborsi Sidoarjo 082244058007 Obat Penggugur Kandungan, Arin Najwa, Jual Obat Aborsi Obat Penggugur Kandungan

arin najwa

Obat Telat Haid 3 Bulan Di Medan Wa 0838 432 696 77, Klinik Dokter Nakal Medan

klinik dokter nakal Medan

Elastic And Shear Moduli Of Single-Walled Carbon Nanotube Ropes, Nancy Burnham, Jean-Paul Salvetat, G Andrew D Briggs, Jean-Marc Bonard, Revathi Bacsa, Andrzej Kulik, Thomas Stöckli, László Forró

Nancy A. Burnham

Carbon nanotubes are believed to be the ultimate low-density high-modulus fibers, which makes their characterization at nanometer scale vital for applications. By using an atomic force microscope and a special substrate, the elastic and shear moduli of individual single-walled nanotube (SWNT) ropes were measured to be of the order of 1 TPa and 1 GPa, respectively. In contrast to multiwalled nanotubes, an unexpectedly low intertube shear stiffness dominated the flexural behavior of the SWNT ropes. This suggests that intertube cohesion should be improved for applications of SWNT ropes in high-performance composite materials.

A Reappraisal Of Article I, Section 27, John Dernbach

John C. Dernbach

No abstract provided.

Synthesis Of Bulk Polycrystalline Indium Nitride At Subatmospheric Pressures., Jeffrey Dyck, K. Kash, C. Hayman, A. Argoitia, M. Grossner, J. Angus, W.-L. Zhou

Jeffrey Dyck

Polycrystalline, wurtzitic indium nitride was synthesized by saturating indium with nitrogen from microwave plasma sources. The structure was confirmed by x-ray diffraction, electron diffraction, and elemental analysis. Two types of growth were observed: (i) dendritic crystals on the original melt surface, and (ii) hexagonal platelets adjacent to the In metal source on the upper edge of the crucible. The method does not involve a foreign substrate to initiate growth and is a potential alternative to the high-pressure techniques normally associated with bulk growth of indium nitride. The lattice parameters were a = 3.5366 ± 0.0005 angstrom and c = 5.7009 …

Graded Functional Activation In The Visuo-Spatial System With The Amount Of Task Demand, Patricia Carpenter, Marcel Just, Timothy Keller, William Eddy, Keith Thulborn

Marcel Adam Just

No abstract provided.

Statistical Analysis Of Reliability, Maintainability And Supportability Data, Caroline Lubert

Caroline P Lubert

No abstract provided.

Mathematica In Action, Stan Wagon

Stan Wagon, Retired

No abstract provided.

Geodynamic Interpretation Of Regional Unconformities: Research Fund Eustacy Or Tectonics?, Daniel Goldman

Daniel Goldman

Funding agency: Petroleum Research Fund Investigators: C.E. Mitchell, Dr. Goldman Amount: $ 6,500.00

Optimization Methods For Logical Inference, Vijay Chandru, John Hooker

John Hooker

No abstract provided.

Growth Of Oriented Thick Films Of Gallium Nitride From The Melt., Jeffrey Dyck, K. Kash, M. Grossner, C. Hayman, A. Argoitia, N. Yang, M.-H. Hong, M. Kordesch, J. Angus

Jeffrey Dyck

While significant strides have been made in the optimization of GaN-based devices on foreign substrates, a more attractive alternative would be homoepitaxy on GaN substrates. The primary motivation of this work is to explore the growth of thick films of GaN from the melt for the ultimate use as substrate material. We have previously demonstrated the synthesis of polycrystalline, wurtzitic gallium nitride and indium nitride by saturating gallium metal and indium metal with atomic nitrogen from a microwave plasma source. Plasma synthesis avoids the high equilibrium pressures required when molecular nitrogen is used as the nitrogen source. Here we report …

Consumption Adjustment Under Time-Varying Income Uncertainty, Douglas Steigerwald, Joon-Ho Hahm

Douglas G. Steigerwald

We study the effect of income uncertainty on consumption in a model that includes precautionary saving. In contrast to previous studies, we focus on time-series variation in income uncertainty. Our time-series measure of income uncertainty is constructed from a panel of forecasts. We find evidence of precautionary saving in that increases in income uncertainty are related to increases in aggregate rates of saving. We also find evidence that anticipated income growth rates have less explanatory power for consumption growth rates after conditioning on income uncertainty. The evidence indicates the presence of forward-looking consumers who gradually adjust precautionary savings in response …

Alternative Polynomial And Holomorphic Dunford-Pettis Properties, Walden Freedman

Walden Freedman

Conditional Convergence Of Infinite Products, William F. Trench

William F. Trench

No abstract provided.