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1996

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Articles 2251 - 2280 of 2437

Full-Text Articles in Physical Sciences and Mathematics

Determination Of Sin2Θw Eff Using Jet Charge Measurements In Hadronic Z Decays, D. Buskulic, M. Thulasidas Jan 1996

Determination Of Sin2Θw Eff Using Jet Charge Measurements In Hadronic Z Decays, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

The electroweak mixing angle is determined with high precision from measurements of the mean difference between forward and backward hemisphere charges in hadronic decays of the Z. A data sample of 2.5 million hadronic Z decays recorded over the period 1990 to 1994 in the ALEPH detector at LEP is used. The mean charge separation between event hemispheres containing the original quark and antiquark is measured forbb¯bb¯ andcc¯cc¯ events in subsamples selected by their long lifetimes or using fastD*’s. The corresponding average charge separation for light quarks is measured in an inclusive sample from the anticorrelation between charges of opposite …


Mathematical Rebuses, Florentin Smarandache Jan 1996

Mathematical Rebuses, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

No abstract provided.


Effects Of Electron Irradiation And Percent Composition On The Glass Transition Temperature And Damping Of Boron-Epoxy Composites, Ian Ivan Nieves Jan 1996

Effects Of Electron Irradiation And Percent Composition On The Glass Transition Temperature And Damping Of Boron-Epoxy Composites, Ian Ivan Nieves

Dissertations, Theses, and Masters Projects

No abstract provided.


Water Quality Modeling As An Inverse Problem, Jian Shen Jan 1996

Water Quality Modeling As An Inverse Problem, Jian Shen

Dissertations, Theses, and Masters Projects

An inverse mathematical estuarine eutrophication model has been developed. The model provides a framework to estimate unknown parameters by assimilation of the concentration data of those state variables. The inverse model developed is a laterally integrated, two-dimensional, real-time model which consists of a hydrodynamic model, an eutrophication model and an adjoint model. The hydrodynamic model provides the dynamic fields for both the eutrophication model and the adjoint model. The eutrophication model simulates eight water quality state variables which are phytoplankton, organic nitrogen, ammonium nitrogen, nitrite-nitrate nitrogen, organic phosphorus, inorganic (ortho) phosphorus, carbonaceous biochemical oxygen demand and dissolved oxygen. The adjoint …


Perkinsus Marinus Extracellular Proteases: Modulation Of Production By Environmental Factors And Effects On The Host Defense Parameters Of The Eastern Oyster Crassostrea Virginica, Kathleen A. Garreis Jan 1996

Perkinsus Marinus Extracellular Proteases: Modulation Of Production By Environmental Factors And Effects On The Host Defense Parameters Of The Eastern Oyster Crassostrea Virginica, Kathleen A. Garreis

Dissertations, Theses, and Masters Projects

No abstract provided.


A Bipartite Model Of Distributed Systems: Possibilities And Implications, Anna Karin Brunstrom Jan 1996

A Bipartite Model Of Distributed Systems: Possibilities And Implications, Anna Karin Brunstrom

Dissertations, Theses, and Masters Projects

Networking software is generally designed in layers. User processes exist at the application layer. They rely on the transport layer to provide them with end-to-end communication. In the distributed systems literature communication is traditionally viewed from the application layer. at the application layer we have no knowledge of the whereabouts of a message once a send operation is completed. at the transport layer, on the other hand, information about the delivery of a message to the transport layer in the receiving host is often available. We believe transport layer information can be better utilized in distributed systems design. This dissertation …


Transport In Chaotic Systems, Xian Zhu Tang Jan 1996

Transport In Chaotic Systems, Xian Zhu Tang

Dissertations, Theses, and Masters Projects

This dissertation addresses the general problem of transport in chaotic systems. Typical fluid problem of the kind is the advection and diffusion of a passive scalar. The magnetic field evolution in a chaotic conducting media is an example of the chaotic transport of a vector field. In kinetic theory, the collisional relaxation of a distribution function in phase space is also an advection-diffusion problem, but in a higher dimensional space.;In a chaotic flow neighboring points tend to separate exponentially in time, exp({dollar}\omega t{dollar}) with {dollar}\omega{dollar} the Liapunov exponent. The characteristic parameter for the transport of a scalar in a chaotic …


Selective Inversion In Solid-State Deuteron Nmr, Marco J. Brown Jan 1996

Selective Inversion In Solid-State Deuteron Nmr, Marco J. Brown

Dissertations, Theses, and Masters Projects

Deuteron NMR selective inversion (SI) is developed to study slow molecular motions in solids. Theoretical and practical aspects of selective inversion of spin-1 nuclei in solids are presented. Differences between powdered solids and liquids are considered. Double sideband modulated (DSBM) shaped pulses are shown to improve the performance of SI pulses. DSBM and DANTE selective pulses are compared for off-resonance SI applications. Common spin-{dollar}{lcub}1{rcub}\over{lcub}2{rcub}{dollar} shaped pulses are tested for suitability to solid state deuteron NMR. Simple, short pulses are shown to be most effective due to fast spin-spin relaxation and large underlying homogeneous linewidths in solids.;The power and utility of …


The Role Of Microbial Food Webs In Benthic-Pelagic Coupling In Freshwater And Marine Ecosystems, Adele J. Pile Jan 1996

The Role Of Microbial Food Webs In Benthic-Pelagic Coupling In Freshwater And Marine Ecosystems, Adele J. Pile

Dissertations, Theses, and Masters Projects

A majority of carbon in freshwater and marine ecosystems is in the form of ultraplankton, heterotrophic and autotrophic plankton &<&5 &\mu&m including heterotrophic bacteria, Prochlorococcus, cyanobacteria, and autotrophic eucaryotes. However, ultraplankton and subsequently microbial food webs have yet to be incorporated into models of benthic-pelagic coupling despite the preponderance of macroinvertebrates with the capacity to feed on ultraplankton. I have examined the role of microbial food webs in benthic-pelagic coupling in three ecosystems: Lake Baikal, Siberia, Russia; Gulf of Maine, Northwest Atlantic Ocean; and Conch Reef, Florida Keys, USA. Using sponges as a model organism and in situ measurements, I have quantified (1) suspension feeding on ultraplankton and (2) release of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) resulting in direct evidence that benthic macroinvertebrates do occupy the level of primary consumer within the microbial food web. Dual-beam flow cytometry was employed to quantified sponge suspension feeding on five types of ultraplankton: heterotrophic bacteria, Synechococcus-type cyanobacteria, autotrophic picoplankton &<&3 &\mu&m, autotrophic eucaryotes 3-10 &\mu&m, and in marine ecosystems Prochlorococcus. Grazing by the freshwater sponges Baikalospongia intermedia and B. bacilliferia and the boreal marine sponge, Mycale lingua, was unselective for all types of ultraplankton with efficiencies ranging from 63-99%. This is the first time that grazing on Synechococcus-type cyanobacteria and Prochlorococcus by macroinvertebrates has been quantified in freshwater and marine ecosystems. Conversely, the coral reef sponges Ircinia felix and I. strobilina release significant amounts of DIN and DIP as a result of grazing on procaryotic plankton. Using a general model for organism-mediated fluxes, it is conservatively estimated that through active suspension feeding sponges in Lake Baikal retain 1.97 g C day&\sp{lcub}-1{rcub}& m&\sp{lcub}-2{rcub}& and M. lingua retains 29 mg C day&\sp{lcub}-1{rcub}& m&\sp{lcub}-2{rcub}& while at Conch Reef sponges released 204 &\mu&mol DIN day&\sp{lcub}-1{rcub}& m&\sp{lcub}-2{rcub}& and 48 &\mu&mol DIP day&\sp{lcub}-1{rcub}& m&\sp{lcub}-2{rcub}&. A majority of the carbon retained at all three locations was from procaryotic cell types suggesting that ultraplankton are an important overlooked component of benthic-pelagic coupling.


Randomized Approximation Of The Constraint Satisfaction Problem, Hoong Chuin Lau, Osamu Watanabe Jan 1996

Randomized Approximation Of The Constraint Satisfaction Problem, Hoong Chuin Lau, Osamu Watanabe

Research Collection School Of Computing and Information Systems

We consider the Weighted Constraint Satisfaction Problem (W-CSP) which is a fundamental problem in Artificial Intelligence and a generalization of important combinatorial problems such as MAX CUT and MAX SAT. In this paper, we prove non-approximability properties of W-CSP and give improved approximations of W-CSP via randomized rounding of linear programming and semidefinite programming relaxations. Our algorithms are simple to implement and experiments show that they are run-time efficient.


Asymptotic Conservation Laws In Classical Field Theory, Ian M. Anderson, Charles G. Torre Jan 1996

Asymptotic Conservation Laws In Classical Field Theory, Ian M. Anderson, Charles G. Torre

Mathematics and Statistics Faculty Publications

A new, general, field theoretic approach to the derivation of asymptotic conservation laws is presented. In this approach asymptotic conservation laws are constructed directly from the field equations according to a universal prescription which does not rely upon the existence of Noether identities or any Lagrangian or Hamiltonian formalisms. The resulting general expressions of the conservation laws enjoy important invariance properties and synthesize all known asymptotic conservation laws, such as the Arnowitt-Deser-Misner energy in general relativity.


Introduction To Multiprocessor I/O Architecture, David Kotz Jan 1996

Introduction To Multiprocessor I/O Architecture, David Kotz

Dartmouth Scholarship

The computational performance of multiprocessors continues to improve by leaps and bounds, fueled in part by rapid improvements in processor and interconnection technology. I/O performance thus becomes ever more critical, to avoid becoming the bottleneck of system performance. In this paper we provide an introduction to I/O architectural issues in multiprocessors, with a focus on disk subsystems. While we discuss examples from actual architectures and provide pointers to interesting research in the literature, we do not attempt to provide a comprehensive survey. We concentrate on a study of the architectural design issues, and the effects of different design alternatives.


Superconvergence Of The Iterated Galerkin Methods For Hammerstein Equations, Hideaki Kaneko, Yuesheng Xu Jan 1996

Superconvergence Of The Iterated Galerkin Methods For Hammerstein Equations, Hideaki Kaneko, Yuesheng Xu

Mathematics & Statistics Faculty Publications

In this paper, the well-known iterated Galerkin method and iterated Galerkin-Kantorovich regularization method for approximating the solution of Fredholm integral equations of the second kind are generalized to Hammerstein equations with smooth and weakly singular kernels. The order of convergence of the Galerkin method and those of superconvergence of the iterated methods are analyzed. Numerical examples are presented to illustrate the superconvergence of the iterated Galerkin approximation for Hammerstein equations with weakly singular kernels. © 1996, Society for Industrial and Applied Mathematics


Data Compression Based On The Cubic B-Spline Wavelet With Uniform Two-Scale Relation, S. K. Yang, C. H. Cooke Jan 1996

Data Compression Based On The Cubic B-Spline Wavelet With Uniform Two-Scale Relation, S. K. Yang, C. H. Cooke

Mathematics & Statistics Faculty Publications

The aim of this paper is to investigate the potential artificial compression which can be achieved using an interval multiresolution analysis based on a semiorthogonal cubic B-spline wavelet. The Chui-Quak [1] spline multiresolution analysis for the finite interval has been modified [2] so as to be characterized by natural spline projection and uniform two-scale relation. Strengths and weaknesses of the semiorthogonal wavelet as regards artificial compression and data smoothing by the method of thresholding wavelet coefficients are indicated.


An Efficient Runge-Kutta (4,5) Pair, P. Bogacki, L. F. Shampine Jan 1996

An Efficient Runge-Kutta (4,5) Pair, P. Bogacki, L. F. Shampine

Mathematics & Statistics Faculty Publications

A pair of explicit Runge-Kutta formulas of orders 4 and 5 is derived. It is significantly more efficient than the Fehlberg and Dormand-Prince pairs, and by standard measures it is of at least as high quality. There are two independent estimates of the local error. The local error of the interpolant is, to leading order, a problem-independent function of the local error at the end of the step.


Dynamical Simulation Of The Simplest Hydrides, Donald Greenspan Jan 1996

Dynamical Simulation Of The Simplest Hydrides, Donald Greenspan

Mathematics Technical Papers

In agreement with recent results of Gell-Mann and Hartle, we approximate electron motions in ground state Li7H1 and Li7H2 using an energy conserving numerical method for the solution of Newton's equations and a novel assumption about the interaction of the bonding electrons. Initial calculations for the first excited state of Li7H1 are also discussed. I. Introduction. Quantum dynamics is usually perceived through the time dependent Schrödinger equation, for which related analytical and computational problems appear to be insurmountable at the present time. There is however an alternate approach which can be implemented readily when the dynamical behavior is periodic. This …


Minimum Path Problems In Normed Spaces, Reflection And Refraction, Michael Golomb, Mostafa Ghandehari Jan 1996

Minimum Path Problems In Normed Spaces, Reflection And Refraction, Michael Golomb, Mostafa Ghandehari

Mathematics Technical Papers

The main minimum (or extremum) path problem in this paper deals with the "law of refraction" at a curve separating the plane into two parts with different norms. Analytic and geometric characterization for the point at which refraction takes place and formulas for the angles that this incident and refracted rays make with a fixed axis or with the normal to the curve are established. The case where the unit circle of the two norms are Euclidean circles with different radii leads to the traditional Snell's Law. The other problem deals with the "law of reflection" from a curve in …


Conservative Motion Of Discrete, Tetrahedral Top On A Smooth Horizontal Plane, Donald Greenspan Jan 1996

Conservative Motion Of Discrete, Tetrahedral Top On A Smooth Horizontal Plane, Donald Greenspan

Mathematics Technical Papers

Tetrahedral tops are simulated as discrete, rigid bodies in rotation by introducing a molecular mechanics formulation. The contact point of the top with the XY plane is allowed to move in the plane. The conservative, dynamical differential equations are solved numerically in such a fashion that all the system invariants are preserved. Examples which include precession, nutation, cusp formation, and looping are described and discussed.


Two Remarks On Totally Balanced Games, Juan-Enrique Martínez-Legaz Jan 1996

Two Remarks On Totally Balanced Games, Juan-Enrique Martínez-Legaz

Mathematics Technical Papers

Two results on totally balanced TU games are presented. It is first shown that the core of any subgame of a non-negative totally balanced game can be easily obtained from the maximal average value function of the game. The second result is a characterization of convex games as those games all of whose marginal games are totally balanced.


Maine Implements The Clean Air Act: Federalism, Environmentalism And Interest Group Accountability, Jon Reisman Jan 1996

Maine Implements The Clean Air Act: Federalism, Environmentalism And Interest Group Accountability, Jon Reisman

Maine Policy Review

The implementation of environmental policy initiatives often brings about a complex interplay between science and policy, public opinion, interest groups, federal and state mandates, and political machination. Jon Reisman uses Maine’s recent experience of compliance with the 1990 Clean Air Act to illustrate this complexity. In doing so, he addresses several important, but often ignored, issues, such as stakeholder participation in the policy making process, interest group accountability to implementation, and the long term consequences to the environment if these issues are avoided.


1996 Maine Water Resources Conference Summary Jan 1996

1996 Maine Water Resources Conference Summary

Maine Policy Review

No abstract provided.


[(Co)H(Pph3)2-Arachno-Osb3h8], Nigam Rath, J. Bould, L. Barton Jan 1996

[(Co)H(Pph3)2-Arachno-Osb3h8], Nigam Rath, J. Bould, L. Barton

Chemistry & Biochemistry Faculty Works

A single-crystal X-ray diffraction study of the species 2-carbonyl2-hydrido-trans-2,2-bis(triphenylphosphine)-2-osma-arachno-tetraborane confirms the structure as a tetraborane(10) butterfly with a trans-[(CO)H(PPh3)2Os] group replacing a BH2 group at a wing-tip or 2-position. It is compared with the previously reported ruthenaborane analogue (CO)H(PPh3)2-arachno-RuB3H8.


On Noninvertible Mappings Of The Plane: Eruptions, Lora Billings, James H. Curry Jan 1996

On Noninvertible Mappings Of The Plane: Eruptions, Lora Billings, James H. Curry

Department of Mathematics Facuty Scholarship and Creative Works

In this paper we are concerned with the dynamics of noninvertible transformations of the plane. Three examples are explored and possibly a new bifurcation, or ‘‘eruption,’’ is described. A fundamental role is played by the interactions of fixed points and singular curves. Other critical elements in the phase space include periodic points and an invariant line. The dynamics along the invariant line, in two of the examples, reduces to the one-dimensional Newton’s method which is conjugate to a degree two rational map. We also determine, computationally, the characteristic exponents for all of the systems. An unexpected coincidence is that the …


Seismogeological Features Of The Crust In Romania, V Mocanu, C Dinu, F Radulescu, M Diaconescu, Camelia C. Diaconescu, A Pompilian Jan 1996

Seismogeological Features Of The Crust In Romania, V Mocanu, C Dinu, F Radulescu, M Diaconescu, Camelia C. Diaconescu, A Pompilian

Faculty Publications

The Romanian area consists of old consolidated units of pre-Alpine age (the Moesian, Moldavian and Scythian platforms) and Alpine orogenic units (the Carpathian arc and North-Dobrudjan orogen). General seismogeological peculiarities of the pre-Alpine tectonic units are presented, as well as some structural characteristics of the Transylvanian Basin and the Pannonian Depression. Both shallow and deep seismic reflection/refraction data as well as log information and some potential field data were used for the investigation of the crustal structure. The varibility in the seismogeological pattern and crustal thickness shown by the different tectonic units is due to the differences in structure and …


Deep R-Band Surface Photometry Of Ngc891, Eric Miller Jan 1996

Deep R-Band Surface Photometry Of Ngc891, Eric Miller

Honors Papers

Understanding how galaxies evolve is a challenge for astronomers, given the very long timescales for such evolution to occur. Fortunately, the structure of a galaxy encodes a fossil record of its evolution. In particular, by decomposing this structure into a number of independent components, we can compare the results to theoretical predictions and begin to trace the history of mass accretion and star formation that have shaped the stellar systems we see today.

In this thesis, I present deep optical R-band surface photometry of the nearby edge-on spiral galaxy NGC891. This galaxy bears many similarities to the Milky Way, and …


Artificial Maturation Of Alginite And Organic Groundmass Separated From Torbanites, Michael A. Kruge, Patrick Landais, David F. Bensley Jan 1996

Artificial Maturation Of Alginite And Organic Groundmass Separated From Torbanites, Michael A. Kruge, Patrick Landais, David F. Bensley

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The two principal organic constituents — Botryococcus-related alginite and organic groundmass — were isolated by density separation from two torbanite samples (from the Stellarton Fm., Nova Scotia, Canada and the King Cannel, Utah, USA). The groundmass consisted of degraded algal, bacterial and terrestrial plant debris. Aliquots of alginite and groundmass were separately heated in gold tubes for 24 hr. with 70 MPa confining pressure, at fixed temperatures ranging between 250 and 375°C. The 250, 300 and 325°C experiments run on the alginite produced very low yields of CHCl3-extractable organic matter (EOM), indicating that very little of the generation potential …


An Analysis Of Shewhart Quality Control Charts To Monitor Both The Mean And Variability, Keith Jacob Barrs Jan 1996

An Analysis Of Shewhart Quality Control Charts To Monitor Both The Mean And Variability, Keith Jacob Barrs

Legacy ETDs

When monitoring the mean of a continuous quality measure it is often recommended a separate chart be used to monitor the variability. These charts are traditionally designed separately. This project considers them together as a combined charting procedure and gives recommendations for their design. This is based on an average run length (ARL) analysis. The run length distribution is determined using two methods both based on a Markov chain approach.


Patterns Of Phytoplankton Abundance And Nutrient Concentration In The York River Estuary, Virginia: 1984-1994, Yongsik Sin, Richard L. Wetzel Jan 1996

Patterns Of Phytoplankton Abundance And Nutrient Concentration In The York River Estuary, Virginia: 1984-1994, Yongsik Sin, Richard L. Wetzel

Reports

No abstract provided.


Hydrodynamics Of Sediment Suspensions In The Littoral Zone Of The Lower York River - Phase Ii, John D. Boon Jan 1996

Hydrodynamics Of Sediment Suspensions In The Littoral Zone Of The Lower York River - Phase Ii, John D. Boon

Reports

This report covers the second year (Phase II) of a two-year study. An earlier contract report (Boon,1996) was submitted in January, 1996, to the Virginia Coastal Resources Management Program covering the first year (Phase I) results of a wave , current and suspended sediment monitoring study conducted at the mouth of the York River (Figure 1).

The purpose of the monitoring study , as originally planned , was to investigate processes governing sediment suspension within the shallow waters of the littoral zone (depths< 2m) in coastal estuaries. These are regions in which bottom sediment, in the absence of vegetative cover and depending on sediment grain sizes present, has the potential to be actively eroded and entrained in the water column by wind waves and/or currents. Suspended sediment has the further potential to impact water quality and promote eutrophication through nutrient enrichment processes (Kemp et al., 1983; Orth and Moore, 1983). High sediment loadings also lead to light reduction in the photic zone which can impact the growth or survival of submerged aquatic vegetation (De Groot and de Jonge, 1990) .


Hydrodynamics Of Sediment Suspensions In The Littoral Zone Of The Lower York River - Phase I, John D. Boon Jan 1996

Hydrodynamics Of Sediment Suspensions In The Littoral Zone Of The Lower York River - Phase I, John D. Boon

Reports

Motivation for this study derives from a need to know more about processes governing sediment suspension within the shallow waters of the littoral zone (depths< 2m) in coastal estuaries. These are regions in which bottom sediment, in the absence of vegetative cover and depending on grain sizes present, has the potential to be actively eroded and entrained in the water column by wind waves and/or currents. Suspended sediment has the further potential to impact water quality and promote eutrophication through nutrient enrichment processes (Kemp et al., 1983; Orth and Moore, 1983). High sediment loadings also lead to light reduction in the photic zone which can impact the growth or survival of submerged aquatic vegetation (De Groot and de Jonge, 1990).