Physical Sciences and Mathematics Commons^™

Closed-Orbit Theory Of Oscillations In Atomic Photoabsorption Cross Sections In A Strongelectric Field. I. Comparison Between Theory And Experiments On Hydrogen And Sodium Above Threshold, J. Gao, John B. Delos, M. Baruch

Arts & Sciences Articles

Using a simple analytic formula from closed-orbit theory, we calculate photoabsorption cross sections of hydrogen and sodium in a strong electric field. The theoretical spectra show good agreement with experimental results. A scaled variable measurement is also suggested.

Current Trends In Ecologic-Economic Valuation Of Wetlands, Laura Mitchell, Laura Grignano

Reports

No abstract provided.

Closed-Orbit Theory Of Oscillations In Atomic Photoabsorption Cross Sections In A Strong Electric Field. Ii. Derivation Of Formulas, J. Gao, John B. Delos

Arts & Sciences Articles

A formula for photoabsorption cross sections of hydrogen and alkali-metal atoms in a static electric field is derived, based on the closed-orbit theory previously used to study hydrogen in a magnetic field. Electric fields are simpler than magnetic fields, because the classical motion is regular and closed orbits can be enumerated. In alkali metals the core modifies the relevant dipole matrix elements, and it produces additional phase shifts.

The State Of The Art In Wetlands Modeling: An Emphasis On Techniques And Technologies, William J. Seufzer, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.

Public Oyster Shoal Survey - Spring 1992, Bruce J. Barber

Reports

Oysters have been harvested from Virginia waters as long as humans have inhabited the area. Depletion of natural stocks in the late 1880's led to the establishment of regulations by public fisheries agencies. A survey of bottom areas in which oysters grew naturally was completed in 1896 under the direction of Lt. Baylor, USN. These areas (over 243,000 acres) were set aside by legislative action for public use and have come to be known as the Baylor Survey Grounds or Public Oyster Grounds of Virginia, and are presently administered by VMRC, the Virginia Marine Resources Commission (Haven et al., 1978). …

A Three-Dimensional Environmental Fluid Dynamics Computer Code : Theoretical And Computational Aspects, John M. Hamrick

Reports

This report describes and documents the theoretical and computational aspects of a three-dimensional computer code for environmental fluid flows. The code solves the three-dimensional primitive variable v1ertically hydrostatic equations of motion for turbulent flow in a coordinate system which is curvilinear and orthogonal in the horizontal plane and stretched to follow bottom topography and free surface displacement in the vertical direction which is aligned with the gravitational vector. A second moment turbulence closure scheme relates turbulent viscosity and diffusivity to the turbulence intensity and a turbulence length scale. Transport equations for the turbulence intensity and length scale as well as …

Temporal And Spatial Variations In Chesapeake Bay Water Quality: A Video Data Report, Sarah E. Rennie, Bruce Neilson

Reports

Over the past two years we have been developing computer programs to investigate various scientific visualization techniques as applied to estuarine data. The original impetus was to be able to visualize the results of the three-dimensional hydrodynamic model under development at the Virginia Institute of Marine Science, College of William and Mary (VIMS). We quickly recognized the superior ability of certain graphic approaches, especially pseudocolor animation, to efficiently transmit a tremendous amount of information to the viewer, allowing the scientist to gain an insight into the dynamics of the data not otherwise available. We decided to apply this technique to …

Bank Erosion Study, C. Scott Hardaway Jr., George R. Thomas, J. B. Glover, J. B. Smithson, Marcia Berman, A. K. Kenne

Reports

The Bank Erosion Study was designed to evaluate eroding fast land bank shorelines as contributors of sand, silt and clay and total nitrogen and total phosphorous introduced into the Chesapeake Bay estuarine system. In addition, the extent and effectiveness of erosion control measures were evaluated for selected shoreline reaches. Fastland banks are the uplands along the shorelines that are composed of semi-consolidated sediments. This study evaluates about 2000 miles of primary tidal shoreline in the Virginia portion of the Chesapeake Bay estuarine system for areas of fast land bank erosion. Primary tidal shorelines are those along the main stem of …

Water Quality In Chesapeake Bay : Virginia Portion, Water Year 1988 : A Report To The Virginia Water Control Board, Kevin Curling, Bruce Neilson

Reports

The purpose of this report is to characterize water quality conditions during the 1988 water year, October 1987 through September 1988. For the most part, the information is provided in graphical format. Only data for the Virginia portion of Chesapeake Bay is included. No data analysis or interpretation is included, since this is the stated purpose of several other reports. This report will be useful to both scientists and managers who need ready access to some portion of the data on a regular basis. With this report it is possible to quickly examine seasonal patterns, compare conditions at two stations, …

Tidal Freshwater Swamps Of The Lower Chesapeake Bay, Richard D. Rheinhardt, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.

The Virginia Wetlands Report Vol. Vii, No. 1, Virginia Institute Of Marine Science

Virginia Wetlands Reports

• Dredge Spoil Oysters. Walter I. Priest, III
• Marsh Wren. Julie G. Bradshaw
• Dredge Spoil Oysters. Walter I. Priest, III
• Spotted Seatrout. Lyle Varnell
• A Local Board’s Experience with Civil Charges and Penalties. Edwin Rosenberg

Hamiltonian Bifurcation Theory Of Closed Orbits In The Diamagnetic Kepler Problem, J. M. Mao, John B. Delos

Arts & Sciences Articles

Classically chaotic systems possess a proliferation of periodic orbits. This phenomenon was observed in a quantum system through measurements of the absorption spectrum of a hydrogen atom in a magnetic field. This paper gives a theoretical interpretation of the bifurcations of periodic or closed orbits of electrons in atoms in magnetic fields. We ask how new periodic orbits can be created out of existing ones or ‘‘out of nowhere’’ as the energy changes. Hamiltonian bifurcation theory provides the answer: it asserts the existence of just five typical types of bifurcation in conservative systems with two degrees of freedom. We show …

Field Testing The Proposed Federal Wetlands Delineation Manual, James E. Perry, Julie G. Bradshaw, Kirk J. Havens, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.

Status Of The Major Oyster Diseases In Virginia 1991 A Summary Of The Annual Monitoring Program, Eugene M. Burreson

Reports

No abstract provided.

Transport Of Hypoxic Waters: An Estuary-Subestuary Exchange, A. Y. Kuo, K. Park

VIMS Books and Book Chapters

Hypoxic or anoxic conditions in the subpycnocline water of Chesapeake Bay persist throughout the summer. The effect on the dissolved oxygen concentration in the deep basin of the lower Rappahannock River, a subestuary on the western side of the bay, was studied with an observational program. The data indicate that in the lower portion of the water column the subtidal (or residual) current was directed into the subestuary most of the time. The mass fluxes of salt and dissolved oxygen into the subestuary through a point near the estuarine bottom at the river mouth were calculated for tidal and subtidal …

Code Generation Using A Backtracking Lr Parser, Laurie Anne Smith King

Dissertations, Theses, and Masters Projects

Although the parsing phase of the modern compiler has been automated in a machine independent fashion, the diversity of computer architectures inhibits automating the code generation phase. During code generation, some intermediate representation of a source program is transformed into actual machine instructions. The need for portable compilers has driven research towards the automatic generation of code generators.;This research investigates the use of a backtracking LR parser that treats code generation as a series of tree transformations.

Allozyme Analysis Of Billfish Population Structure, Lee W. Morgan

Dissertations, Theses, and Masters Projects

No abstract provided.

Survival And Abundance Of Juvenile Caribbean Spiny Lobster: Effects Of Shelter Size And Geographic Location, Jonathon Daniel Mintz

Dissertations, Theses, and Masters Projects

No abstract provided.

Generic Identification And Patterns Of External Pigment In Larval Gobies (Pisces: Gobiidae) From The Belize Barrier Reef, Elizabeth D. Maddox

Dissertations, Theses, and Masters Projects

No abstract provided.

Central Atlantic Coastal Plain - A Summary Of The Geological Evolution Of Chesapeake Bay, Eastern United States, Steven M. Colman, Jeffrey P. Halka, C. Hobbs

VIMS Books and Book Chapters

The seaward margin of the U.S. Atlantic Coastal Plain has fluctuated through time, from near the Fall Line to near the edge of the present Outer Continental Shelf, owing to changes in relative sea level. The strata that underlie the Coastal Plain were deposited in environments that ranged from fully terrestrial to fully marine. Estuarine environments are critical components of the Coastal Plain; they represent the interface, otherwise known as the shoreline, between the marine and terrestrial depositional systems. The Quaternary evolution of estuaries has important implications for both documenting the history of sea-level changes and interpreting ancient coastal-plain strata. …

Ecological Functions And Values Of Nontidal Wetlands, Carl H. Hershner

VIMS Books and Book Chapters

Reviews the current understanding of the functions of nontidal wetlands, assesses the· problems of assigning values to wetland functions, and surveys the use of these functions and values in management programs of the mid-Atlantic states.

Shoreline Habitat Selection By Bald Eagles (Haliaeetus Leucocephalus) In A Non-Breeding Eagle Concentration-Area On The James River, Virginia, Kennedy H. Clark

Dissertations, Theses, and Masters Projects

No abstract provided.

Intelligent Processing Of Pmr-15, Sean Michael Hart

Dissertations, Theses, and Masters Projects

No abstract provided.

Distribution, Abundance, And Behavior Of The Cownose Ray, Rhinoptera Bonasus (Mitchill 1815), In Lower Chesapeake Bay, Robert A. Blaylock

Dissertations, Theses, and Masters Projects

Aspects of the ecology of the cownose ray, Rhinoptera bonasus, in the lower Chesapeake Bay and its tributaries were studied using aerial surveys, biotelemetry, and examination of stomach contents. The Chesapeake Bay was surveyed by airplane during 1986-1989, to examine the distribution of cownose rays and estimate their abundance using line transect methods. Cownose rays resided in Chesapeake Bay throughout the summer months, entering in early June and emigrating in late September. They were usually absent, or nearly so, by late October. Mean monthly abundance ranged from none present in May and November, to a September average of 9.3 &\cdot& …

A Comparison Of Grow-Out Methods For The Bay Scallop, Argopecten Irradians Irradians, At Two Sites In Virginia, Mark J. Brotman

Dissertations, Theses, and Masters Projects

No abstract provided.

Role Of Habitat Features And Chemical Cues In Substrate Selection By Blue Crab Megalopae: Evidence From Laboratory Experiments, Bruce Clare Layman

Dissertations, Theses, and Masters Projects

No abstract provided.

Measurement Of The Carbon And Nitrogen Densities Of The Marine Heterotrophic Flagellate Paraphysomonas Sp, Yongsik Sin

Dissertations, Theses, and Masters Projects

No abstract provided.

Land Use And Wetland Function: A Sensitivity Analysis Of The Vims Nontidal Wetland Functional Assessment Method, Martha Craig

Dissertations, Theses, and Masters Projects

No abstract provided.

The Branching Fraction Of Long-Lived Kaon Going To Muon-Anti-Muon, Michael David Chapman

Dissertations, Theses, and Masters Projects

This thesis presents the results of a measurement of the branching fraction of the $K\sb{L}\to\mu\bar{\mu}$ decay. This decay is scGIM supressed in the Standard Model, and provides a useful test of that model. Additionally, the degree of deviation from the unitary limit provides a useful test for several other models. The experiment was performed at the Brookhaven National Laboratory Alternating Gradient Synchrotron facility. The apparatus consisted of a two-magnet mass spectrometer, together with dual electromagnetic and muon particle identification systems. A total of 281 $K\sb{L}\to\mu\bar{\mu}$ events were observed. Normalizing to the 15,768 $K\sb{L}\to\pi\bar{\pi}$ events observed results in a branching fraction …

Completion Of Partial Operator Matrices, M.(Mihaly) Bakonyi

Dissertations, Theses, and Masters Projects

This work concerns completion problems for partial operator matrices. A partial matrix is an m-by-n array in which some entries are specified and the remaining are unspecified. We allow the entries to be operators acting between corresponding vector spaces (in general, bounded linear operators between Hilbert spaces). Graphs are associated with partial matrices. Chordal graphs and directed graphs with a perfect edge elimination scheme play a key role in our considerations. A specific choice for the unspecified entries is referred to as a completion of the partial matrix. The completion problems studied here involve properties such as: zero-blocks in certain …