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California Polytechnic State University, San Luis Obispo

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Articles 2311 - 2340 of 2553

Full-Text Articles in Physical Sciences and Mathematics

Partitioning Inequalities In Probability And Statistics, Theodore P. Hill Jan 1993

Partitioning Inequalities In Probability And Statistics, Theodore P. Hill

Research Scholars in Residence

This article surveys fair-division or cake-cutting inequalities in probability statistics, including bisection inequalities, basic fairness inequalities, convexity tools, superfairness inequalities, and partitioning inequalities hypotheses testing and optimal stopping theory. The emphasis is measure theoretic, as opposed to game theoretic or economic, and a number of open problems in the area are mentioned.

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Nonstandard And Standard Compactifications Of Ordered Topological Spaces, Sergio Salbany, Todor D. Todorov Nov 1992

Nonstandard And Standard Compactifications Of Ordered Topological Spaces, Sergio Salbany, Todor D. Todorov

Mathematics

We construct the Nachbin ordered compactification and the ordered realcompactification, a notion defined in the paper, of a given ordered topological space as nonstandard ordered hulls. The maximal ideals in the algebras of the differences of monotone continuous functions are completely described. We give also a characterization of the class of completely regular ordered spaces which are closed subspaces of products of copies of the ordered real line, answering a question of T.H. Choe and Y.H. Hong. The methods used are topological (standard) and nonstandard.

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Giant Sequoia Insect, Disease, And Ecosystem Interactions, Douglas D. Piirto Jun 1992

Giant Sequoia Insect, Disease, And Ecosystem Interactions, Douglas D. Piirto

Natural Resources Management and Environmental Sciences

Individual trees of giant sequoia (Sequoia gigantea [Lindl.] Decne.) have demonstrated a capacity to attain both a long life and very large size. It is not uncommon to find old-growth giant sequoia trees in their native range that are 1,500 years old and over 15 feet in diameter at breast height. The ability of individual giant sequoia trees to survive over such long periods of time has often been attributed to the species high resistance to disease, insect, and fire damage. Such a statement, however, is a gross oversimplification, given broader ecosystem and temporal interactions. For example, why isn't …

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On The Game Of Googol, Theodore P. Hill, Ulrich Krengel Jun 1992

On The Game Of Googol, Theodore P. Hill, Ulrich Krengel

Research Scholars in Residence

In the classical secretary problem the decision maker can only observe the relative ranks of the items presented. Recently, Ferguson — building on ideas of Stewart — showed that, in a game theoretic sense, there is no advantage if the actual values of the random variables underlying the relative ranks can be observed (game of googol). We extend this to the case where the number of items is unknown with a known upper bound. Corollary 3 extends one of the main results in [HK] to all randomized stopping times. We also include a modified, somewhat more formal argument for Ferguson's …

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The Three-Line Magnetic Hyperfine Spectrum Of 57Fe, Norman A. Blum, Richard B. Frankel May 1992

The Three-Line Magnetic Hyperfine Spectrum Of 57Fe, Norman A. Blum, Richard B. Frankel

Physics

Longitudinal magnetization of a 57Co in iron metal foil source and an iron metal foil absorber in a uniform external magnetic field results in a simple three-line magnetic hyperfine absorption spectrum. Measurement of the spectral splitting as a function of applied magnetic field yields the 57Fe excited-and ground-state g-factors.

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Pointwise Kernels Of Schwartz Distributions, Todor D. Todorov Mar 1992

Pointwise Kernels Of Schwartz Distributions, Todor D. Todorov

Mathematics

We show that Schwartz distributions have kernels in the class of the pointwise nonstandard functions.

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A P-Adic Cohomological Method For The Weierstrass Family And Its Zeta Invariants, Goro Kato Jan 1992

A P-Adic Cohomological Method For The Weierstrass Family And Its Zeta Invariants, Goro Kato

Mathematics

After a survey of the Weierstrass family and cohomology, we compute the lifted homology of the Weierstrass family with compact supports so that explicit formulae for the zeta function of each fibre of the Weierstrass family may be obtained. The (co-)homology theory that we use is found in [L1], [L2] and [L3]. Therefore, this article can be regarded as an application of Lubkin's p-adic theory of cohomologies to an algebraic family called the Weierstrass scheme over the ring (Z/pZ)[g2,g3). The cohomological background for the computation will be rather carefully exploited.

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A Binary Tree Decomposition Space Of Permutation Statistics, Don Rawlings Jan 1992

A Binary Tree Decomposition Space Of Permutation Statistics, Don Rawlings

Mathematics

Based on the binary tree decomposition of a permutation, a natural vector space of permutation statistics is defined. Besides containing many well known permutation statistics, this space provides the general context for an archetypal recurrence relationship that contains most of the classic combinatorial sequences and some of their known generalizations.

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Riemannian Geometry Of Orbifolds, Joseph Ernest Borzellino Jan 1992

Riemannian Geometry Of Orbifolds, Joseph Ernest Borzellino

Mathematics

We investigate generalizations of many theorems of Riemannian geometry to Riemannian orbifolds. Basic definitions and many examples are given. It is shown that Riemannian orbifolds inherit a natural stratified length space structure. A version of Toponogov's triangle comparison theorem for Riemannian orbifolds is proven. A structure theorem for minimizing curves shows that such curves cannot pass through the singular set. A generalization of the Bishop relative volume comparison theorem is presented. The maximal diameter theorem of Cheng is generalized. A finiteness result and convergence result is proven for good Riemannian orbifolds, and the existence of a closed geodesic is shown …

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One-Sided Refinements Of The Strong Law Of Large Numbers And The Glivenko-Cantelli Theorem, David Gilat, Theodore P. Hill Jan 1992

One-Sided Refinements Of The Strong Law Of Large Numbers And The Glivenko-Cantelli Theorem, David Gilat, Theodore P. Hill

Research Scholars in Residence

A one-sided refinement of the strong law of large numbers is found for which the partial weighted sums not only converge almost surely to the expected value, but also the convergence is such that eventually the partial sums all exceed the expected value. The new weights are distribution-free, depending only on the relative ranks of the observations. A similar refinement of the Glivenko-Cantelli theorem is obtained, in which a new empirical distribution function not only has the usual uniformly almost-sure convergence property of the classical empirical distribution function, but also has the property that all its quantiles converge almost surely. …

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A Survey Of Prophet Inequalities In Optimal Stopping Theory, Theodore P. Hill, Robert P. Kertz Jan 1992

A Survey Of Prophet Inequalities In Optimal Stopping Theory, Theodore P. Hill, Robert P. Kertz

Research Scholars in Residence

This paper surveys the origin and development of what has come to be known as "prophet inequalities" in optimal stopping theory. Included is a review of all published work to date on these problems, including extensions and variations, descriptions and examples of the main proof techniques, and a list of a number of basic open problems.

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Variation Of Superparamagnetic Properties With Iron Loading In Mammalian Ferritin, Richard B. Frankel, G. C. Papaefthymiou, G. D. Watt Nov 1991

Variation Of Superparamagnetic Properties With Iron Loading In Mammalian Ferritin, Richard B. Frankel, G. C. Papaefthymiou, G. D. Watt

Physics

The average blocking temperatures of ferritin molecules containing differing amounts of iron were determined by Mossbauer spectroscopy. The results imply that the magnetic anisotropy of the ferritin core particles is a function of particle volume. By addition of 57Fe to ferritin core particles it was determined that, at a given temperature within the superpara-magnetic temperature region, the “last-in” ferric ions have average relaxation times that are shorter than those of the bulk ferric ions.

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Visual Interaction: A Link Between Perception And Problem Solving, Erika Rogers, Ronald C. Arkin Oct 1991

Visual Interaction: A Link Between Perception And Problem Solving, Erika Rogers, Ronald C. Arkin

Computer Science and Software Engineering

The approach taken in this research is to develop a cognitive model of how a human observer extracts information from a visual display and then uses this perceptual information in a decision-making task. Knowledge about this relationship provides information about the occurrence of perceptual events in the course of problem-solving activities, and suggests that perceptual assistance in the form of image enhancements is a useful supplement to the user’s own abilities. This knowledge is then to be embedded in an intelligent computerized assistant which is designed to facilitate and stimulate the human problem-solving process.

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Inorganic Particles Produced By Microorganisms, Richard B. Frankel Oct 1991

Inorganic Particles Produced By Microorganisms, Richard B. Frankel

Physics

The processes by which microorganisms, particularly bacteria, produce inorganic mineral particles are reviewed.

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Structure, Morphology And Growth Of Biogenic Greigite (Fe3S4), Brigid R. Heywood, Stephen Mann, Richard B. Frankel Oct 1991

Structure, Morphology And Growth Of Biogenic Greigite (Fe3S4), Brigid R. Heywood, Stephen Mann, Richard B. Frankel

Physics

Several species of aquatic bacteria are known to exploit the earth's geomagnetic field as a means of directing their motion towards suitable habitats. A feature common to these bacteria is the presence of discrete intracellular magnetic inclusions, magnetosomes, aligned in chains along the long axis of the organism. The size and orientation of the individual magnetic particles imparts a permanent magnetic dipole moment to the cell which is, in turn, responsible for the magnetotactic response. In all species examined to date the magnetic particles have been found to be well-ordered, single domain, membrane-bounded crystals with reproducible, species-specific morphologies. Until recently, …

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Paper Or Plastic?, Matthew J. Moelter Sep 1991

Paper Or Plastic?, Matthew J. Moelter

Physics

Letter to the Editor.

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Visual Interaction In Diagnostic Radiology, Erika Rogers, Ronald C. Arkin, M. Baron May 1991

Visual Interaction In Diagnostic Radiology, Erika Rogers, Ronald C. Arkin, M. Baron

Computer Science and Software Engineering

The concept of Visual Interaction is introduced as the process which links perception and problem-solving such that problem-solving is affected by what is seen, and conversely, what is seen and perceived is affected by the current state of the problem-solving process. This paper describes the development of a cognitively-based model of the visual interaction process in diagnostic radiology, and shows how aspects of this model are being incorporated into the design and implementation of an intelligent computer-based radiological assistant. In order to achieve this, it is necessary to extract information about the nature and type of knowledge involved in this …

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Method For The Automatic Level Adjustment In A Local Area Network, In Particular For A Multiprocessor Arrangement With A Bus System Of Optical Fibres, For The Purpose Of Collision Detection, Hans Thinschmidt, Franz J. Kurfess May 1991

Method For The Automatic Level Adjustment In A Local Area Network, In Particular For A Multiprocessor Arrangement With A Bus System Of Optical Fibres, For The Purpose Of Collision Detection, Hans Thinschmidt, Franz J. Kurfess

Computer Science and Software Engineering

European Patent. Written in German.

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Redox Capacity Of Apo Mammalian Ferritin, Gerald D. Watt, Richard B. Frankel Mar 1991

Redox Capacity Of Apo Mammalian Ferritin, Gerald D. Watt, Richard B. Frankel

Physics

No abstract provided.

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Iron Biominerals: An Overview, Richard B. Frankel Mar 1991

Iron Biominerals: An Overview, Richard B. Frankel

Physics

No abstract provided.

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Biomineralization Of Iron Sulfides In Magnetotactic Bacteria From Sulfidic Environments, Dennis A. Bazylinski, Richard B. Frankel, Anthony J. Garratt-Reed, Stephen Mann Mar 1991

Biomineralization Of Iron Sulfides In Magnetotactic Bacteria From Sulfidic Environments, Dennis A. Bazylinski, Richard B. Frankel, Anthony J. Garratt-Reed, Stephen Mann

Physics

No abstract provided.

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Intercellular Junctions, Motility, And Magnetosome Structure In A Multicellular Magnetotactic Prokaryote, Frank G. Rodgers, Richard P. Blakemore, Nancy A. Blakemore, Richard B. Frankel, Dennis A. Bazylinski, Denise Maratea, Christine Rodgers Mar 1991

Intercellular Junctions, Motility, And Magnetosome Structure In A Multicellular Magnetotactic Prokaryote, Frank G. Rodgers, Richard P. Blakemore, Nancy A. Blakemore, Richard B. Frankel, Dennis A. Bazylinski, Denise Maratea, Christine Rodgers

Physics

A many-celled, magnetotactic, prokaryote obtained from brackish water possessed intercellular connections at points of contact between the outer membranes of constituent cells. These connections structurally resembled the "gap junctions" found in eukaryotes. Each aggregate organism consisted of 10 to 30 individual gram-negative cells containing material with the appearance of poly-𝛽-hydroxybutyrate and magnetosomes of unusual arrangement, structure and composition. The aggregate, which possessed prokaryotic-type flagella arranged at the outward surfaces of each cell, showed motility indicative of coordination between individual component cells. These results suggest that this organism is a multicellular prokaryote.

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Electronic Properties Of Monocapped Prismane And Basket Iron-Sulphur Clusters, B. S. Snyder, M. S. Reynolds, R. H. Holm, G. C. Papaefthymiou, R. B. Frankel Jan 1991

Electronic Properties Of Monocapped Prismane And Basket Iron-Sulphur Clusters, B. S. Snyder, M. S. Reynolds, R. H. Holm, G. C. Papaefthymiou, R. B. Frankel

Physics

The ground state electronic properties of the mixed-valence clusters Fe7S6 (PEt3)4Cl3 (1), Fe6S6(PEt3)4L2 [L = Cl− (2), Br− (4), I− (5) and PhS− (6)], Fe6Se6 (PEt3)4Cl2 (3) and [Fe6S6(PEt)6]1− (9), have been investigated by magnetic susceptibility, magnetization and Mössbauer spectroscopic measurements. Cluster 1 has a (idealized C3v) monocapped prismane structure and clusters 2–6 and 9 adopt the C2v “basket” configuration based on the [Fe6 …

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Magnetic Fine Particles In Biological Systems, Dominic P.E. Dickson, Richard B. Frankel Jan 1991

Magnetic Fine Particles In Biological Systems, Dominic P.E. Dickson, Richard B. Frankel

Physics

Two examples of biological magnetic fine particles are considered: iron-storage proteins and magnetotactic bacteria. These cover many aspects of this field, including the use of well-defined biological systems for testing theoretical models, using magnetic properties to distinguish between different biological materials, producing magnetic materials by biological processes, and using optimised biological magnetic systems as a guide to the production of synthetic magnetic materials.

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Minimax-Optimal Stop Rules And Distributions In Secretary Problems, Theodore P. Hill, Ulrich Krengel Jan 1991

Minimax-Optimal Stop Rules And Distributions In Secretary Problems, Theodore P. Hill, Ulrich Krengel

Research Scholars in Residence

For the secretary (or best-choice) problem with an unknown number N of objects, minimax-optimal stop rules and (worst-case) distributions are derived, under the assumption that $N$ is a random variable with unknown distribution, but known upper bound n. Asymptotically, the probability of selecting the best object in this situation is of order of (log n)-1. For example, even if the only information available is that there are somewhere between 1 and 100 objects, there is still a strategy which will select the best item about one time in five.

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A Nonstandard Delta Function, Todor D. Todorov Dec 1990

A Nonstandard Delta Function, Todor D. Todorov

Mathematics

We prove that the Dirac delta distribution has a kernel in the class of the pointwise nonstandard functions.

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Controlled Biosynthesis Of Greigite (Fe3S4) In Magnetotactic Bacteria, Brigid R. Heywood, Dennis A. Bazylinski, Anthony J. Garratt-Reed, Stephen Mann, Richard B. Frankel Nov 1990

Controlled Biosynthesis Of Greigite (Fe3S4) In Magnetotactic Bacteria, Brigid R. Heywood, Dennis A. Bazylinski, Anthony J. Garratt-Reed, Stephen Mann, Richard B. Frankel

Physics

No abstract provided.

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Mossbauer Spectroscopy Of Fe2+ Binding To Apo And Holo Mammalian Ferritin, Richard B. Frankel, Gerald D. Watt, Georgia C. Papaefthymiou Oct 1990

Mossbauer Spectroscopy Of Fe2+ Binding To Apo And Holo Mammalian Ferritin, Richard B. Frankel, Gerald D. Watt, Georgia C. Papaefthymiou

Physics

The anaerobic binding of Fe2+ to apo and holo Mammalian ferritin has been studied in the pH range from 6.0 to 10.0. Mossbauer spectroscopy of samples in which the added Fe 2+ is enriched in Fe-57 shows that the Fe2+ ions bind to the ferritin core and exchange electrons with Fe3+ ions in the core.

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Review Of Verification And Compliance: A Problem Solving Approach By Michael Krepon & Mary Umberger, Toward A Comprehensive Test Ban By Steve Fetter, And Making Space Defense Work: Must The Superpowers Cooperate? By A. Fenner Milton, M. Scott Davis, & John Parmentola, David W. Hafemeister Sep 1990

Review Of Verification And Compliance: A Problem Solving Approach By Michael Krepon & Mary Umberger, Toward A Comprehensive Test Ban By Steve Fetter, And Making Space Defense Work: Must The Superpowers Cooperate? By A. Fenner Milton, M. Scott Davis, & John Parmentola, David W. Hafemeister

Physics

No abstract provided.

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Magnetic Polarity Fractions In Magnetotactic Bacterial Populations Near The Geomagnetic Equator, F. F. Torres De Araujo, F. A. Germano, L. L. Goncalves, M. A. Pires, Richard B. Frankel Aug 1990

Magnetic Polarity Fractions In Magnetotactic Bacterial Populations Near The Geomagnetic Equator, F. F. Torres De Araujo, F. A. Germano, L. L. Goncalves, M. A. Pires, Richard B. Frankel

Physics

The relative numbers of North-seeking and South-seeking polarity types in natural populations of magnetotactic bacteria were determined at sites on the coast of Brazil. These sites were South of the geomagnetic equator and had upward geomagnetic inclinations of 1–12°. For upward inclinations >6°, South-seeking cells predominated over North-seeking cells by more than a factor of 10. For upward inclinations

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