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1997

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Articles 571 - 600 of 2472

Full-Text Articles in Physical Sciences and Mathematics

Phosphorus And Nitrate Loss From Horticulture On The Swan Coastal Plain, Neil Clifton Lantzke Aug 1997

Phosphorus And Nitrate Loss From Horticulture On The Swan Coastal Plain, Neil Clifton Lantzke

Agriculture reports

(En) The extent of nutrient loss from nine horticultural properties located on the sandy soils of the Swan Coastal Plain was examined. On three of the properties phosphorus (P) loss was measured by monitoring nutrient loads in shallow drains. On the other six properties networks of monitoring bores were installed and both P and nitrate nitrogen (NO3-N) concentrations were monitored. All of the properties except one were located on the low phosphate fixing Bassendean sands. The level of nutrient loss was depend l production areas. High to very high N03-N concentrations were found in the shallow groundwater beneath the production …


The John Muir Newsletter, Fall 1997, The John Muir Center For Regional Studies Aug 1997

The John Muir Newsletter, Fall 1997, The John Muir Center For Regional Studies

Muir Center Newsletters (1981-2015)

Fall 1997 NEWSLETTER Intimacies of a New England Trip: John Muir's 1898 Excursion by j. Parker Huber (Editor's note: Parker Huber, a regular contributor to these ■pages, here excerpts and discusses a few days of John Muir's life from the pages of Muir's journal of 1898 and from his letters.) ohn Muir's extensive travels included five trips to New England, finch occurred in 1893,1896,1898,1903 and 1911. His longest fxposure to New England came in late summer and autumn of 1898. This visit had three phases: first an overnight on Cape Cod, ; which is considered here, followed by a tour …


Systematics Of Stable Isotopes And Radionuclides In Precipitation At Kalamazoo, Michigan, Usa, Madhav V. Machavaram Aug 1997

Systematics Of Stable Isotopes And Radionuclides In Precipitation At Kalamazoo, Michigan, Usa, Madhav V. Machavaram

Dissertations

Precipitation samples were collected at Kalamazoo from June 1992 to March 1995. The samples were analyzed for their 8D and 8lgO values. The 5D - 5I80 relationship is comparable to that of Meteoric Water Line (MWL). The monthly mean isotopic values in precipitation exhibited strong seasonality, being higher in summer and lower in winter months. This behavior is apparently a direct consequence of the temperature effect on isotope fractionation.

The summer precipitation at Kalamazoo is derived predominantly from the water vapor originated in the Gulf of Mexico. A box model calculation showed that a Rayleigh type distillation with Gulf moisture …


Fast Discrete Polynomial Transforms With Applications To Data Analysis For Distance Transitive Graphs, J. R. Driscoll, D. M. Healy, D. N. Rockmore Aug 1997

Fast Discrete Polynomial Transforms With Applications To Data Analysis For Distance Transitive Graphs, J. R. Driscoll, D. M. Healy, D. N. Rockmore

Dartmouth Scholarship

Let $\poly = \{P_0,\dots,P_{n-1}\}$ denote a set of polynomials with complex coefficients. Let $\pts = \{z_0,\dots,z_{n-1}\}\subset \cplx$ denote any set of {\it sample points}. For any $f = (f_0,\dots,f_{n-1}) \in \cplx^n$, the {\it discrete polynomial transform} of f (with respect to $\poly$ and $\pts$) is defined as the collection of sums, $\{\fhat(P_0),\dots,\fhat(P_{n-1})\}$, where $\fhat(P_j) = \langle f,P_j \rangle = \sum_{i=0}^{n-1} f_iP_j(z_i)w(i)$ for some associated weight function w. These sorts of transforms find important applications in areas such as medical imaging and signal processing.

In this paper, we present fast algorithms for computing discrete orthogonal polynomial transforms. For a system …


An Improved Analytical Model For Wormhole Routed Networks With Application To Butterfly Fat-Trees, Ronald I. Greenberg, Lee Guan Aug 1997

An Improved Analytical Model For Wormhole Routed Networks With Application To Butterfly Fat-Trees, Ronald I. Greenberg, Lee Guan

Computer Science: Faculty Publications and Other Works

A performance model for wormhole routed interconnection networks is presented and applied to the butterfly fat-tree network. Experimental results agree very closely over a wide range of load rate. Novel aspects of the model, leading to accurate and simple performance predictions, include (1) use of multiple-server queues, and (2) a general method of correcting queuing results based on Poisson arrivals to apply to wormhole routing. These ideas can also be applied to other networks.


Experimental Investigation Of Nonlinear Dynamics In Single Mode Semiconductor Laser Diodes With Phase Conjugate Feedback, Gordon T. Hengst Aug 1997

Experimental Investigation Of Nonlinear Dynamics In Single Mode Semiconductor Laser Diodes With Phase Conjugate Feedback, Gordon T. Hengst

Theses and Dissertations

The semiconductor laser diode offers a unique system to investigate nonlinear dynamics when optical feedback is applied. Although there is extensive research of laser diodes with optical feedback from normal dielectric mirrors, very little has been done experimentally to analyze the effects of degenerate phase conjugate feedback from a BaTiO3 crystal. This research experimentally investigated the dynamics of a single-mode laser diode with weak phase conjugate feedback using both the self-pumped and double phase conjugate geometries. The experimental results validated a mathematical model which numerically evaluates the Lang-Kobayahsi coupled differential equations. The model simulated the nonlinear behavior of a …


Geophysical Characterization Of A Jp-4 (Lnapl) Contaminated Site At The Wurtsmith, Air Force Base, Oscoda, Michigan, Kristina C. Sprietzer Aug 1997

Geophysical Characterization Of A Jp-4 (Lnapl) Contaminated Site At The Wurtsmith, Air Force Base, Oscoda, Michigan, Kristina C. Sprietzer

Masters Theses

The detection of hydrocarbon contamination in the subsurface using geophysical techniques has been based on the known physical properties of high electrical resistivities (ρa) (low conductivities). However, geophysical field investigations at uncontrolled spill sites yield measurements of low resistivity (high conductivity). The purpose of this study is to test that in the natural environment some hydrocarbon spills (in the case of LNAPLs), can exhibit changes with time due to biodegradation, from electrically resistive to conductive. Since time is an important factor, this hypothesis was tested at a site where the time when a hydrocarbon release occurred is known and where …


Learning Recursive Functions From Approximations, John Case, Susanne Kaufmann, Martin Kummer, Efim Kinber Aug 1997

Learning Recursive Functions From Approximations, John Case, Susanne Kaufmann, Martin Kummer, Efim Kinber

School of Computer Science & Engineering Faculty Publications

This article investigates algorithmic learning, in the limit, of correct programs for recursive functionsffrom both input/output examples offand several interesting varieties ofapproximateadditional (algorithmic) information aboutf. Specifically considered, as such approximate additional information aboutf, are Rose's frequency computations forfand several natural generalizations from the literature, each generalization involving programs for restricted trees of recursive functions which havefas a branch. Considered as the types of trees are those with bounded variation, bounded width, and bounded rank. For the case of learning final correct programs for recursive functions, EX-learning, …


A Generalized Univariate Change-Of-Variable Transformation Technique, Andrew G. Glen, Lawrence Leemis, John H. Drew Aug 1997

A Generalized Univariate Change-Of-Variable Transformation Technique, Andrew G. Glen, Lawrence Leemis, John H. Drew

Arts & Sciences Articles

We present a generalized version of the univariate change-of-variable technique for transforming continuous random variables. Extending a theorem from Casella and Berger [1990. Statistical Inference, Wadsworth and Brooks/Cole, Inc., Pacific Grove, CA] for many-to-1 transformations, we consider more general univariate transformations. Specifically, the transformation can range from 1-to-1 to many-to-1 on various subsets of the support of the random variable of interest. We also present an implementation of the theorem in a computer algebra system that automates the technique. Some examples demonstrate the theorem's application.


A Study Of The Volatile Matter Of Coal As A Function Of The Heating Rate, Enrique Santos Aug 1997

A Study Of The Volatile Matter Of Coal As A Function Of The Heating Rate, Enrique Santos

Masters Theses & Specialist Projects

A study of volatile matter yields as a function of the heating rate was conducted. A suite of 21 coal and coke samples varying in rank from anthracitic to lignitic and heating rates from 10°C/min to about 450°C/min were used in the study. Heating rates up to 60°C per minute, which are typically used in ASTM Test Method 5142 (instrumental Proximate Analysis), were achieved in a macro thermogravimetric analysis (TGA) system. Heating rates of 50-200°C/min were obtained in a micro TGA system. All measurements were made in a nitrogen atmosphere. The results of the study illustrate the dependance of the …


Extraction Of Premafloxacin Radiolabeled With Carbon Fourteen From Loam Soil, Steven Gregory Staskiewicz Aug 1997

Extraction Of Premafloxacin Radiolabeled With Carbon Fourteen From Loam Soil, Steven Gregory Staskiewicz

Masters Theses

Premafloxacin is a fluoroquinolone antibiotic being developed by Pharmacia & Upjohn for veterinary indications. Since the parent drug and possibly metabolites will be applied to soil through the deposition of animal excreta, many regulatory agencies will require environmental assessment testing. In order to determine if 14C-premafloxacin would biodegrade in the soil, loam soil was extracted with solvents and C18 solid phase columns were used to isolate the compound after three weeks of incubation. In addition to extracting the soil, production of 14CO2 was monitored by trapping the degradation by-product in 2 N NaOH. Liquid scintillation counting of …


Reservoir Characterization Of Crystal Field And Analysis Of The Tow#1-3 Hd-1 Well, Montcalm County, Michigan, Heidi Wines Aug 1997

Reservoir Characterization Of Crystal Field And Analysis Of The Tow#1-3 Hd-1 Well, Montcalm County, Michigan, Heidi Wines

Masters Theses

The goal of this project was to characterize the Dundee reservoir of Crystal oil field using the newly drilled Tow #1-3 well data in conjunction with historical well records to evaluate heterogeneity of facies and their controls on oil production.

From the Tow# 1-3 HD-1 well, three major facies were identified in the reservoir. A non-fractured intertidal grainstone facies provides storage of fluids with its uniform permeability and excellent intercrystalline porosity. The supratidal fractured micrites and open marine fractured biomicrites are interbedded with the grainstone facies providing conduits for fluid migration between the facies. Facies are important controls on oil …


Multiple Representation For Understanding Data Structures, Biffah Hancies, Venky Shankararaman, Jose Munoz Aug 1997

Multiple Representation For Understanding Data Structures, Biffah Hancies, Venky Shankararaman, Jose Munoz

Research Collection School Of Computing and Information Systems

In this paper an approach to enhance the learning of abstract computing concepts by novice students is presented. This approach is based on effective use of multiple visual representations, and it was applied within the domain of linear data structures: array, stack, queue and linked list. A prototype computer-based instructional system called MRUDS (Multiple Representation for Understanding Data Structures) was developed and evaluated. It was found from the evaluation that the three presentation modules namely, analogy, representation and algorithm contributed to the students' learning process, each contributing to and reinforcing the effect of the others.


The Self-Organizing Desk, Daniela Rus, Peter De Santis Aug 1997

The Self-Organizing Desk, Daniela Rus, Peter De Santis

Dartmouth Scholarship

The self-organizing desk is a system that enhances a physical desk-top with electronic information. It can remember, organize, update, and manipulate the information contained in the documents on a desk. The system consists of a simple robot eye that can survey the desk, a module for smart extraction of information from the images taken by the robot, a module for representing this information in multiple views, and a module that allows a user to interact with this information.


Cheetahs Are Fast, But Nearly Irrelevant, Calton Pu, Jonathan Walpole, Charles Consel Aug 1997

Cheetahs Are Fast, But Nearly Irrelevant, Calton Pu, Jonathan Walpole, Charles Consel

Computer Science Faculty Publications and Presentations

A brief paper submitted to the NSF Workshop on New Challenges and Directions for Systems Research, held in St. Louis, Mo., July 31-August 1, 1997. Outlines the case for more cooperation among software system architects, and a less reductionistic approach to software development.


Sediments And Shallow Stratigraphy Of A Portion Of The Continental Shelf Of Southeastern Virginia, Carl H. Hobbs Iii Aug 1997

Sediments And Shallow Stratigraphy Of A Portion Of The Continental Shelf Of Southeastern Virginia, Carl H. Hobbs Iii

Reports

A network of high-resolution, seismic-reflection profiles and grab samples of the surficial sediments of the inner continental shelf of southeastern Virginia demonstrate that the Quaternary geology of the region is more complex than indicated by earlier studies. The spatial variability of the surficial sediments depicts active processes, such as outflow from Chesapeake Bay, as well as the underlying geology in outcrops of finer grained sediments near False Cape.

The complexity of the Quaternary geology results from large and small scale fluctuations in sea level. Individual, relatively large-scale, seismostratigraphic units are separated by erosional surfaces formed during the major changes in …


A Cephalometric Study Of The Class Ii Correction Effects Of The Eureka Spring, Ernest L. Stromeyer Aug 1997

A Cephalometric Study Of The Class Ii Correction Effects Of The Eureka Spring, Ernest L. Stromeyer

Loma Linda University Electronic Theses, Dissertations & Projects

The effect of the Eureka Spring appliance, was investigated on 37 consecutively treated, non compliant, bilateral Class II malocclusions, requiring at least 3 mm or more of additional molar correction. The mean pretreatment age of this sample was 13.9 years. All patients were treated by a single clinician utilizing the Eureka Spring. Lateral cephalographs were taken at start of orthodontic treatment (T1), at insertion of Eureka Springs (T2), and at removal of the Eureka Springs (T3). The average treatment interval between T2 and T3 was 4 months. Class II correction occurred almost entirely by dentoalveolar movement, 33% in the maxilla …


Building Multi-Discipline, Multi-Format Digital Libraries Using Clusters And Buckets, Michael L. Nelson Aug 1997

Building Multi-Discipline, Multi-Format Digital Libraries Using Clusters And Buckets, Michael L. Nelson

Computer Science Theses & Dissertations

Our objective was to study the feasibility of extending the Dienst protocol to enable a multi-discipline, multi-format digital library. We implemented two new technologies: cluster functionality and publishing buckets. We have designed a possible implementation of clusters and buckets, and have prototyped some aspects of the resultant digital library.

Currently, digital libraries are segregated by the disciplines they serve ( computer science, aeronautics, etc.), and by the format of their holdings (reports, software, datasets, etc.). NCSTRL+ is a multi-discipline, multi-format digital library (DL) prototype created to explore the feasibility of the design and implementation issues involved with created a …


Statistics For Logisticians, Caroline Lubert Jul 1997

Statistics For Logisticians, Caroline Lubert

Caroline P Lubert

No abstract provided.


Cloning And Conservation Of Biological Diversity: Paradox, Panacea, Or Pandora's Box?, Shaily Menon, Kamaljit Bawa, Leah Gorman Jul 1997

Cloning And Conservation Of Biological Diversity: Paradox, Panacea, Or Pandora's Box?, Shaily Menon, Kamaljit Bawa, Leah Gorman

Shaily Menon

The success of a Scottish team in cloning a mammal from an adult tissue cell has generated considerable speculation in the popular press about potential applications to conservation biology. Possibilities that have been mentioned include cloning endangered species and creating gene banks for the germplasm of rare species. Sensational or inaccurate reports might encourage the mistaken notion that cloning technology is more advanced or reliable than it actually is. More important, such reports might foster the myth that there is no longer an urgency to conserve endangered species or their habitats as long as we have frozen germplasm and cloning …


Using The Quantum Computer To Break Elliptic Curve Cryptosystems, Jodie Eicher, Yaw Opoku Jul 1997

Using The Quantum Computer To Break Elliptic Curve Cryptosystems, Jodie Eicher, Yaw Opoku

Department of Math & Statistics Technical Report Series

This article gives an introduction to Elliptic Curve Cryptography and Quantum Computing. It includes an analysis of Peter Shor’s algorithm for the quantum computer breakdown of Discrete Log Cryptosystems and an analog to Shor’s algorithm for Elliptic Curve Cryptosystems. An extended example is included which illustrates how this modified Shor’s algorithm will work.


Toward A Molecular Theory Of Vapor-Phase Nucleation. V. Self-Consistency In The Decoupled Dimer Limit, K.J. Oh, Xiao Cheng Zeng, H. Reiss Jul 1997

Toward A Molecular Theory Of Vapor-Phase Nucleation. V. Self-Consistency In The Decoupled Dimer Limit, K.J. Oh, Xiao Cheng Zeng, H. Reiss

Xiao Cheng Zeng Publications

The previous papers of this series introduced a molecular i / υ cluster theory of vapor phase nucleation. This theory differs from most conventional ones in that the cluster (due to fluctuation) is not only characterized by its number of particles i but also by a spherical volume υ. Thus the free energy of formation of the cluster is not merely a one-dimensional function of the number of particles i but a two-dimensional function of both i and v (i.e., it is a free energy surface). In the first stage of this development (Refs. 1–3) the theory is based on …


Magneto-Optic Trapping Of Β-Decaying 38km, 37k From An On-Line Isotope Separator, J. A. Behr, A. Gorelov, T. Swanson, O. Hausser, K. P. Jackson, M. Trinczek, U. Giesen, J. M. D'Auria, R. Hardy, T. Wilson, P. Choboter, F, Leblond, L. Buchmann, M. Dombsky, C. D.P. Levy, G. Roy, B. A. Brown, J. Dilling Jul 1997

Magneto-Optic Trapping Of Β-Decaying 38km, 37k From An On-Line Isotope Separator, J. A. Behr, A. Gorelov, T. Swanson, O. Hausser, K. P. Jackson, M. Trinczek, U. Giesen, J. M. D'Auria, R. Hardy, T. Wilson, P. Choboter, F, Leblond, L. Buchmann, M. Dombsky, C. D.P. Levy, G. Roy, B. A. Brown, J. Dilling

Mathematics

A magneto-optic trap (MOT) can provide a well-polarized, backing-free, localized source of radioactive atoms for β-decay experiments. We have trapped approximately 6000 atoms of 38Km ( t1/2 = 0.925s) and 2000 atoms of 37K (1.226 s) produced at the TRIUMF on-line separator TISOL in a vapor-cell MOT. We have measured optical isotope shifts and deduced the nuclear charge radii, which show an unusual lack of change at the neutron number N = 20 shell closure. Plans include a search for scalar contributions to the β+- ν correlation in the 0+→0+ decay …


Nested Hadamard Difference Sets, James A. Davis, Jonathan Jedwab Jul 1997

Nested Hadamard Difference Sets, James A. Davis, Jonathan Jedwab

Department of Math & Statistics Faculty Publications

A Hadamard difference set (HDS) has the parameters (4N2, 2N2N, N2N). In the abelian case it is equivalent to a perfect binary array, which is a multidimensional matrix with elements ±1 such that all out-of-phase periodic autocorrelation coefficients are zero. We show that if a group of the form H × Z2pr contains a (hp2r, √hpr(2√hpr − 1), √hpr(√hpr − 1)) HDS (HDS), p a prime not dividing |H| …


Conjugate Schema In Genetic Search, Sanza Kazadi Jul 1997

Conjugate Schema In Genetic Search, Sanza Kazadi

Sanza Kazadi

Functional optimization is profoundly affected by the use of specific encodings. In one encoding, a particular problem may be simple to undertake, while in another encoding, the problem may be intractible. Genetic algorithms solve optimization problems by making use of schema. By locating schema in a solution vector, the paradigm can settle on a solution that makes use of several schema and combines them via crossover.

We propose a generalization of this idea, conjugate schema. Conjugate schema are disjoint subsets of the basis over which the fitness function can be written as a sum of smaller dimensional functions. We find …


Vacuum Structure Of Two-Dimensional Gauge Theories On The Light Front, Gary Mccartor, David G. Robertson, Stephen S. Pinksy Jul 1997

Vacuum Structure Of Two-Dimensional Gauge Theories On The Light Front, Gary Mccartor, David G. Robertson, Stephen S. Pinksy

Physics Faculty Scholarship

We discuss the problem of vacuum structure in light-front field theory in the context of (1+1)-dimensional gauge theories. We begin by reviewing the known light-front solution of the Schwinger model, highlighting the issues that are relevant for reproducing the θ structure of the vacuum. The most important of these are the need to introduce degrees of freedom initialized on two different null planes, the proper incorporation of gauge field zero modes when periodicity conditions are used to regulate the infrared, and the importance of carefully regulating singular operator products in a gauge-invariant way. We then consider SU(2) Yang-Mills theory in …


Long Dormancy, Low Slip Rate, And Similar Slip‐Per‐Event For The Emerson Fault, Eastern California Shear Zone, Charles M. Rubin, Kerry Sieh Jul 1997

Long Dormancy, Low Slip Rate, And Similar Slip‐Per‐Event For The Emerson Fault, Eastern California Shear Zone, Charles M. Rubin, Kerry Sieh

All Faculty Scholarship for the College of the Sciences

Excavations in a playa along the 1992 rupture of the Emerson fault reveal evidence of two paleoseismic events, with only one large prehistoric rupture in the past 15 millennia. Accelerator mass spectrometer radiocarbon ages of charcoal from playa sediments and from fault‐scarp colluvium directly beneath the playa beds indicate that the last large prehistoric slip event occurred about 9000 ka. Trench‐wall exposures revealed clear evidence of at least one pre‐9 ka rupture at the playa site. The event horizon of this earthquake is between two pedogenic carbonate layers that have radiocarbon ages of 14.8 ka and 24.1 ka, implying that …


Multimedia Data Analysis Using Imagetcl (Extended Version), Charles B. Owen, Fillia Makedon Jul 1997

Multimedia Data Analysis Using Imagetcl (Extended Version), Charles B. Owen, Fillia Makedon

Computer Science Technical Reports

ImageTcl is an new system which provides powerful Tcl/Tk based media scripting capabilities similar to those of the ViewSystem and Rivl in a unique environment that allows rapid prototyping and development of new components in the C++ language. Powerful user tools automate the creation of new components as well as the addition of new data types and file formats. Applications using ImageTcl at the Dartmouth Experimental Visualization Laboratory (DEVLAB) include multiple stream media data analysis, automatic image annotation, and image sequence motion analysis. ImageTcl combines the high speed of compiled languages with the testing and parameterization advantages of scripting languages.


Multiple Media Stream Data Analysis: Theory And Applications (Extended Version), Charles B. Owen, Fillia Makedon Jul 1997

Multiple Media Stream Data Analysis: Theory And Applications (Extended Version), Charles B. Owen, Fillia Makedon

Computer Science Technical Reports

This paper presents a new model for multiple media stream data analysis as well as descriptions of some applications of this model in development at Dartmouth College. This model formalizes the exploitation of correlations between multiple, potentially heterogeneous, media streams in support of numerous application areas. The goal of the technique is to determine temporal and spatial alignments which optimize a correlation function and indicate commonality and synchronization between media streams. It also provides a framework for comparison of media in unrelated domains. Applications such as text-to-speech alignment, functional magnetic resonance imaging, speaker localization, and degraded media realignment are described.


Precision Determination Of The Neutron Spin Structure Function G1n, K Abe, C M. Berisso, S Churchwell, R S. Hicks, Yu G. Kolomensky, Gerald Alvin Peterson Jul 1997

Precision Determination Of The Neutron Spin Structure Function G1n, K Abe, C M. Berisso, S Churchwell, R S. Hicks, Yu G. Kolomensky, Gerald Alvin Peterson

Gerald Alvin Peterson

We report on a precision measurement of the neutron spin structure function g1n using deep inelastic scattering of polarized electrons by polarized 3He. For the kinematic range 0.014