Physical Sciences and Mathematics Commons^™

Storm Surges In The Region Of Western Alaska, Warren Blier, Stanley Keefe, Wilson Shaffer, Sung C. Kim

VIMS Articles

Within the period of the historical record there have been several occurrences of extensive damage from storm-surge-related coastal flooding in the region of Nome, Alaska. The most recent of these events, although by no means the most destructive, occurred in association with the storm of 5–6 October 1992. Despite the small population of Nome (approximately 4000 people), total damage costs exceeded $6 million. The research into the nature and causes of such flooding events has focused on this October 1992 case. The authors have, however, also examined a weaker, shorter-duration event that occurred on 20 August 1993 and, for contrast, …

Investigation Of Isolated Sand Shoals On The Inner Shelf Of Virginia Relative To The Potential For Aggregate Mining : Report On Study Of Possible Wave Force Alternations On The Proposed Dredging At Sandbridge Shoal, Va, Jerome Y.-P. Maa, Carl H. Hobbs Iii

Reports

The Virginia Institute of Marine Science, together with other state agencies, has a continuing interest in preserving the coastline of Virginia, particularly, the Atlantic coastline in the vicinity of the resort city of Virginia Beach. Because a well maintained beach can serve several purposes , e.g., ( 1) providing public recreational areas, (2) protecting valuable properties that are located near coastline , and (3) reducing the rate of land loss, a great deal of efforts has been devoted to understand the processes that affect the change of shoreline. Among several erosion forces , waves are especially important elements as they …

Comparisons Of Gears And Vessels Used In The Virginia Institute Of Marine Science Juvenile Finfish Trawl Survey, David Hata

Reports

The Virginia Institute of Marine Science (VIMS) currently conducts a monthly trawl survey in the three major Virginia rivers and the lower Chesapeake Bay to estimate the abundance of economically important finfish species, particularly at the juvenile stage .. VIM:S has conducted similar trawl surveys in various forms since 1955. Although this represents a 40 year period, variations in sampling design and gear have confounded efforts to produce a meaningful, continuous time series. Such variations include changes in stations occupied, sampling frequency, _vessels, and trawl gears. Much of the trawl survey sampling has been documented (Wojcik and Van Engel 1988a, …

The Oldest Operating Wetland Mitigation Bank In The U.S. A Review Of The Goose Creek Wetland Bank In Chesapeake, Virginia; It's Development And Utilization, Thomas A. Barnard Jr., Carl Hershner, Megan Greiner, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.

Recurrence Spectroscopy Of A Time-Dependent System: A Rydberg Atom In An Oscillating Field, Neal Spellmeyer, Daniel Kleppner, M. R. Haggerty, V. Kondratovich, John B. Delos, J. Gao

Arts & Sciences Articles

We report the results of an experimental and theoretical investigation of the recurrence spectra of Rydberg atoms in a static plus weak oscillating electric field. Experiments reveal the systematic weakening of orbits in a recurrence spectrum as the oscillating field strength and frequency are changed. We describe a generalization of closed orbit theory to time-dependent systems and show that it provides a qualitative and quantitative description of the phenomena.

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 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.

Closed-Orbit Theory And The Photodetachment Cross Section Of H- In Parallel Electric And Magnetic Fields, Aaron D. Peters, Charles Jaffé, J. B. Delos

Arts & Sciences Articles

In this paper we obtain a simple analytic formula for the photodetachment cross section of H− in parallel electric and magnetic fields. The three-dimensional semiclassical approximation predicts oscillations in the spectrum and correlates these oscillations with closed classical orbits. The cylindrical symmetry of the Hamiltonian produces some interesting effects. In particular, at boundary energies the semiclassical approximation fails as a focused cusp approaches the origin.

Quantum Manifestations Of Bifurcations Of Closed Orbits In The Photodetachment Cross Section Of H- In Parallel Fields, Aaron D. Peters, Charles Jaffé, J. Gao, John B. Delos

Arts & Sciences Articles

In the preceding paper, we showed that the semiclassical approximation diverges at a bifurcation, and that this divergence coincides with the passage of a focused cusp through the origin. Here we obtain a wave function in the vicinity of this cusp, and we use that wave function to eliminate the divergences in the photodetachment cross section. To describe the focused cusp, we first discuss the wave function of an ordinary two-dimensional (nonfocused) cusp. This wave function is known as a Pearcey function, and it has been studied extensively. Then we show how the formulas that lead to the Pearcey function …

Semiclassical Formula For Oscillator Strengths In Atomic Spectra, V. Kondratovich, John B. Delos

Arts & Sciences Articles

A simple semiclassical formula is given for the oscillator strengths of high Rydberg states of a hydrogen atom in an electric field. The oscillator strength of a state is proportional to the square of the function representing the quantum angular distribution of outgoing waves, evaluated at the classical angle of ejection from the atom that sends the electron into a semiclassically quantized eigentrajectory. The formula gives an interpretation of the envelopes of Stark manifolds in photoabsorption spectra; it is in good agreement with quantum calculations. The formula may also be used for other integrable or near-integrable systems.

Quantum Manifestations Of Bifurcations Of Closed Orbits In The Photoabsorption Spectra Of Atoms In Electric Fields, J. Gao, John B. Delos

Arts & Sciences Articles

The methods developed in the preceding paper (paper II) are used to construct a wave function near a bifurcation of classical orbits of an atomic electron in an electric field. A formula for the recurrence strength near the bifurcation is derived and compared with experimental measurements.

Symmetry Breaking In Crossed Magnetic And Electric Fields, C. Neumann, R. Ubert, S. Freund, Et Al., John B. Delos

Arts & Sciences Articles

We present the first observations of cylindrical symmetry breaking in highly excited diamagnetic hydrogen with a small crossed electric field, and we give a semiclassical interpretation of this effect. As the small perpendicular electric field is added, the recurrence strengths of closed orbits decrease smoothly to a minimum, and revive again. This phenomenon, caused by interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.

Phenotypic Selection In An Intertidal Snail: Effects Of A Catastrophic Storm, G. Trussell

VIMS Articles

Littorina obtusata exhibits clear morphological variation (e.g. shell height, shell length, and aperture area) among shores differentially exposed to wave energies. Selection imposed by the hydrodynamic environment is often invoked to explain the correlation between morphology and wave exposure in intertidal organisms, but rarely is this hypothesis tested. I examined the effects of a catastrophic storm on the shell length and relative shell height and aperture area of L. obtusata populations on 2 protected and 1 wave-exposed share in New England (USA) to test this hypothesis. Snails sampled after the storm had relatively squatter shells than those sampled before the …

Geological And Geophysical Character Of The East China And Yellow Seas, John D. Milliman, Nicole D. Scott

Reports

The East China and Yellow seas represent one of the broadest shallow seas in the global ocean, with water depths generally less than 80 m and stretching nearly 750 km from the Shandong Peninsula to the Okinawa Trough (Fig. 1). This area is also unique in terms of the vast amount of sediment it receives from the Huanghe (Yellow River; presently discharging in the adjacent Gulf of Bohai) and the Changjigang (Yangtze River, which flows into the East China Sea). Together, this region receives about ten percent of the river-derived sediment reaching the ocean, and as such, the region has …

Status Of The Major Oyster Diseases In Virginia 1996 A Summary Of The Annual Monitoring Program, Lisa M. Ragone Calvo, Eugene M. Burreson

Reports

No abstract provided.

1997 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

Effects Of Seagrass Biology On Water Quality In Shallow Regions Of The Lower Chesapeake Bay : Final Report, Kenneth A. Moore

Reports

The changes in water quality within shallow water regions of the lower Chesapake Bay was compared seasonally from permanent stations located along transects across vegetated and unvegetated sites in shoal regions of the lower Chesapeake Bay. The effect of the seagrass bed on conditions inside compared to outside of the bed varied seasonally and could be related to bed biomass and develoment. During spring (April-June) the rapidly growing seagrass bed was a sink for nutrients, suspended inorganic particles and phytoplankton, while during the summer, as bed dieback progressed, resuspension and release of nutrients were observed. Reductions in suspended particle concentrations …

1997 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

Chesapeake Bay Hall Dedication, Virginia Institute Of Marine Science, School Of Marine Science, College Of William And Mary

Miscellaneous

Dedication: April 25, 1997. Invitation to dedication ceremony and program booklet. List of research laboratories provided.

1997 Wachapreague Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

Storm Surges In The Region Of Western Alaska, Warren Blier, Stanley Keefe, Wilson A. Shaffer, Sung C. Kim

VIMS Articles

Within the period of the historical record there have been several occurrences of extensive damage from storm-surge-related coastal flooding in the region of Nome, Alaska. The most recent of these events, although by no means the most destructive, occurred in association with the storm of 5–6 October 1992. Despite the small population of Nome (approximately 4000 people), total damage costs exceeded $6 million.

The research into the nature and causes of such flooding events has focused on this October 1992 case. The authors have, however, also examined a weaker, shorter-duration event that occurred on 20 August 1993 and, for contrast, …

Trophic Effects Of Sponge Feeding Within Lake Baikal's Littoral Zone .2. Sponge Abundance, Diet, Feeding Efficiency, And Carbon Flux, Aj Pile, Mark R. Patterson, M. Savarese, V I. Chernykh, V A. Fialkov

VIMS Articles

Endemic freshwater demosponges in the littoral zone of Lake Baikal, Russia, dominate the benthic biomass, covering 44% of the benthos. We measured in situ sponge abundance and,orating and calculated sponge-mediated Fluxes of picoplankton (plankton <2 mu m) for two common species, Baikalospongia intermedia and Baikalospongia bacillifera. By means of dual-beam how cytometry, we found retention efficiencies ranging from 58 to 99% for four types of picoplankton: heterotrophic bacteria, Synechococcus-type cyanobacteria, autotrophic picoplankton with one chloroplast, and autotrophic picoplankton with two chloroplasts. By using a general model for organism-mediated fluxes, we conservatively estimate that through active suspension feeding, sponges are a sink for 1.97 g C d(-1) m(-1), mostly from procaryotic cell types. Furthermore, grazing by these extensive sponge communities can create a layer of picoplankton-depleted water overlying the benthic community in this unique lake.

Organic Carbon Abundance, Distribution And Metabolism At The Oyster, Virginia Study Site, Elizabeth Canuel, Iris C. Anderson, Craig Tobias

Reports

This report describes a pilot study conducted at the DOE Subsurface Science Program's study site in Oyster, VA. The objective of this study was to examine whether 2 organic matter associated with the solid and dissolved phases was labile enough to support microbial activity. Organic matter availability was assessed in two ways: (1) by quantifying the amount and distribution of total organic carbon (TOC) associated with the solid phase and (2) laboratory experiments to examine the utilization of dissolved organic matter by measuring total microbial respiration. In addition to assessing total respiration, we specifically addressed organic matter respiration via denitrification. …

Body Burden Of Polycyclic Aromatic Hydrocarbons And Tributyltin In Hard Clams, Mercenaria Mercenaria From The Elizabeth River, Va, Morris H. Roberts, Michael A. Unger

Reports

The Elizabeth River, contaminated with PAH, TBT, and heavy metals, is potentially home to a variety of estuarine invertebrates of commercial importance, notably oysters, hard clams, and crabs. Harvestable oysters have virtually disappeared from the system, but it has been rumored among commercial fishermen that a population of small (little neck to cherrystone) hard clams (Mercenaria mercenaria) exists within the Elizabeth River system. These clams are of serious interest to commercial clammers in the area as a previously unharvested source of market-size clams. Crabs of a harvestable size are also reasonably abundant throughout this river according to local fishermen.

The …

Virginia's Commercial Fishing Industry: Its Economic Performance And Contributions, James Kirkley

Reports

No abstract provided.

Semiclassical Picture Of Collision-Induced Λ-Doublet Transitions In Diatomic Molecules, Laurie J. Kovalenko, J. B. Delos

Arts & Sciences Articles

We investigate collision-induced Λ-doublet transitions in a system similar to NO+Ar, based on a semiclassical model in which nuclear motion is treated classically and electronic motion quantum mechanically. We present a picture of this process by monitoring〈Λ〉, the expectation value of the projection of electronic orbital-angular momentum onto the molecular NO axis, over the duration of the collision. In a typical collision, the interaction with Ar would cause the electronic orbital-angular momentum to precess about the rotating NO–Ar vector. However, since this angular momentum is locked tightly to the diatomic axis, it is restricted to oscillation along this axis. This …

Semiclassical Model Of Λ-Doublet States In Diatomic Molecules, Laurie J. Kovalenko, John B. Delos

Arts & Sciences Articles

An intuitive picture of Λ-doubling in diatomic molecules is presented using a semiclassical theory. A common view of Λ-doubling as arising from electrons “lagging” behind the rotating internuclear axis is shown to be misleading; rather, the eigenfunctions are symmetric about the molecular axes and can be expressed as a superposition of pure nonrotating orbitals and travelling waves. These results are shown to be consistent with a full quantum treatment. We also examine, for the first time, time-dependent states, by monitoring expectation values of electronic- and nuclear-angular momenta. For low rotation frequency, the expectation value of the electronic-angular momentum locks onto …

Development Of Monitoring Protocol For Created Wetlands : Project Summary For 1997, James E. Perry

Reports

Appx. 1. Annotated bibliography -- Appx. 2. Field data sheet - Appx. 3.Monitoring protocol manual for created wetlands: draft manual.

Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And The Coastal Bays - 1996, Robert J. Orth, Judith F. Nowak, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagy

Reports

SA V distribution data in this report are presented and discussed based on the segmentation scheme adopted by the Chesapeake Bay Program (Flemer et al., 1983) and described briefly in the Methods section of this report. This zonation scheme (Upper, Middle, and Lower zones) for Chesapeake Bay, which accommodates the Chesapeake Bay Program segmentation boundaries, was adapted from that used in previous SAV distribution reports (i.e., Orth et al., 1994) and established by Orth and Moore ( 1982), then modified by Orth et al., ( 1989). The 1996 data were edgematched using ARC/INFO GIS software, as were all the historical …

Saltwater Angling And Its Economic Importance To Virginia, James Kirkley, David Kerstetter

Reports

No abstract provided.