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Articles 3001 - 3030 of 4602

Full-Text Articles in Physical Sciences and Mathematics

The Crest, Winter 1999, Virginia Institute Of Marine Science Jan 1999

The Crest, Winter 1999, Virginia Institute Of Marine Science

Reports

Table of Contents:

  • Experimental Fishery on Georges Bank Holds Promise for the Scallop Industry
  • New VIMS Center Boosts Aquafarming
  • Invader Threatens Stressed Ecosystem (Rapa Whelk)
  • Microscopic Phytoplankton Live Large
  • Reality By the Numbers (Computer Modeling)
  • Tautog Research
  • Latest Returns From the Game Fish Tagging Program
  • Educational Landscape Center (VIMS Teaching Marsh)
  • Responding to the Chesapeake Executive Council Directive for Wetlands Protection and Restoration Goals
  • Dangers to Blue Crabs Accelerating


Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And The Coastal Bays - 1998, R J. Orth, Judith F. Nowak, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagey Jan 1999

Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And The Coastal Bays - 1998, R J. Orth, Judith F. Nowak, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagey

Reports

No abstract provided.


Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And The Coastal Bays - 1997, R J. Orth, Judith F. Nowak, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagey Dec 1998

Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And The Coastal Bays - 1997, R J. Orth, Judith F. Nowak, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagey

Reports

No abstract provided.


Semiclassical Representation Of Width-Weighted Spectra, M. W. Beims, V. Kondratovich, John B. Delos Nov 1998

Semiclassical Representation Of Width-Weighted Spectra, M. W. Beims, V. Kondratovich, John B. Delos

Arts & Sciences Articles

We consider a system having decaying states with complex energies Ej−iΓj/2, and we define the “width-weighted spectrum” as DΓ(E)=ΣjΓjδ(E−Ej). We derive a semiclassical formula for this width-weighted spectrum, a formula which is analogous to the periodic-orbit representation of the density of states. The formula applies if classical motion is regular and if decay occurs by tunneling through a barrier. The semiclassical formula involves not periodic orbits or closed orbits, but action integrals associated with irreducible loops on the “extremal torus,” on which the particle climbs up the barrier and hangs at the top. Calculations confirm the validity of the formula.


Laser In-Situ Scattering And Transmissometer (Lisst) Observations In Support Of The Sensor Insertion System Duck, Nc October, 1997, Grace M. Massey, Carl T. Friedrichs Nov 1998

Laser In-Situ Scattering And Transmissometer (Lisst) Observations In Support Of The Sensor Insertion System Duck, Nc October, 1997, Grace M. Massey, Carl T. Friedrichs

Reports

The objective of this portion of the study was to collect LIS ST time series at times corresponding to collection of pumped samples of suspended sediment across the width of the surf zone during a major field experiment called SandyDuck '97. The pumped samples were analyzed for total percent sand (>60 micron), total percent mud (0.8 - 60 micron), organic content and sand size distribution. The LISST measures the particle size distribution from 5-500 microns. The purpose was to provide a high quality data set of pumped samples with which to later test the sensitivity of indirect measurements of …


Public Policy: Integrated Approaches To Environmental Policy, Karla S. Havens, Virginia Institute Of Marine Science, Wetlands Program Nov 1998

Public Policy: Integrated Approaches To Environmental Policy, Karla S. Havens, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.


The Virginia Wetlands Report Vol. 13, No. 3, Virginia Institute Of Marine Science Oct 1998

The Virginia Wetlands Report Vol. 13, No. 3, Virginia Institute Of Marine Science

Virginia Wetlands Reports

  • Tundra Swan. Julie G. Bradshaw
  • What kind of educational courses and publications does the Wetlands Program offer? William Roberts
  • Mummichog. Lyle Varnell
  • Using Remote Sensing and GIS To Perform Jurisdictional Wetlands Determinations. Marcia Berman
  • United States v. Wilson: Muddy Waters in the Search for Wetlands Protection. S. Fagan and Jim Perry
  • Responding to the Chesapeake Executive Council Directive for Wetlands Protection and Restoration Goals. Carl Hershner
  • Wetlands: A Critical Resource in the Revolutionary War? Pam Mason


Extracting Classical Trajectories From Atomic Spectra, M. R. Haggerty, Neal Spellmeyer, Daniel Kleppner, John B. Delos Aug 1998

Extracting Classical Trajectories From Atomic Spectra, M. R. Haggerty, Neal Spellmeyer, Daniel Kleppner, John B. Delos

Arts & Sciences Articles

We describe how to reconstruct individual classical trajectories from spectroscopic data. The ac dipole moment of a trajectory can be found from the effect of an oscillating field on the spectrum. The inverse Fourier transform of such data yields the component of the electron trajectory along the direction of the oscillating field. We demonstrate the method by experimentally extracting z(t) for two electron trajectories that influence the Stark spectrum of Rydberg lithium. Within the experimental resolution, the reconstructed orbits agree well with classical predictions.


The Virginia Wetlands Report Vol. 13, No. 2, Virginia Institute Of Marine Science Jul 1998

The Virginia Wetlands Report Vol. 13, No. 2, Virginia Institute Of Marine Science

Virginia Wetlands Reports

  • Wood Duck. Julie G. Bradshaw
  • Striped Killifish. Lyle Varnell
  • An Update on the Virginia Geographic Information Network. Marcia R. Berman
  • Wild Rice. Pam Mason
  • What is riprap? Is it preferred over a bulkhead for shoreline erosion control? William Roberts
  • An Introduction to Stressed Habitats. James E. Perry, John E. Anderson, and Arnold F. Theisen


Postimpact Deformation Associated With The Late Eocene Chesapeake Bay Impact Structure In Southeastern Virginia, Gerald H. Johnson, Sarah E. Kruse, Allison W. Vaughn, John K. Lucey, C. Hobbs, David S. Powars Jun 1998

Postimpact Deformation Associated With The Late Eocene Chesapeake Bay Impact Structure In Southeastern Virginia, Gerald H. Johnson, Sarah E. Kruse, Allison W. Vaughn, John K. Lucey, C. Hobbs, David S. Powars

VIMS Articles

Upper Cenozoic strata covering the Chesapeake Bay impact structure in southeastern Virginia record intermittent differential movement around its buried rim. Miocene strata in a graben detected by seismic surveys on the York River exhibit variable thickness and are deformed above the crater rim. Fan-like interformational and intraformational angular unconformities within Pliocene–Pleistocene strata, which strike parallel to the crater rim and dip2°–3° away from the crater center, indicate that deformation and deposition were synchronous.Concentric, large-scale crossbedded, bioclastic sand bodies of Pliocene age within ~20 km of the buried crater rim formed on offshore shoals, presumably as subsiding listric slump blocks rotated …


Semiclassical Formula For Oscillator Strengths Of Atomic Spectra In External Fields, V. Kondratovich, John B. Delos Jun 1998

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

Arts & Sciences Articles

In a previous Rapid Communication [Phys. Rev. A 56, R5 (1997)] we reported a semiclassical formula describing oscillator strengths for transitions to a high Rydberg state of a hydrogen atom in an electric field. The formula relates the oscillator strength for an atomic transition into a Rydberg state to the angular distribution of outgoing electron waves and to the density of classical tori. Here we give a derivation of that formula and we suggest some generalizations. We compare the formula with experimental measurements of the absorption spectrum of hydrogen in an electric field. This absorption spectrum consists of quasidiscrete resonances …


Scaled-Energy Floquet Spectroscopy In A Strong Electric Field: A Semiquantal Calculation Of The Recurrence Spectrum, V. Kondratovich, John B. Delos Jun 1998

Scaled-Energy Floquet Spectroscopy In A Strong Electric Field: A Semiquantal Calculation Of The Recurrence Spectrum, V. Kondratovich, John B. Delos

Arts & Sciences Articles

We consider a hydrogen atom in a strong static electric field with a weak parallel radio-frequency (rf) field. We compute the photoabsorption spectrum by calculating the spectrum of Floquet states, including their quasienergies and their oscillator strengths. Our calculation is based upon “semiquantal” formulas: we calculate the discrete spectrum of quasienergy states by using a quantum adiabatic approximation combined with semiclassical (Bohr-Sommerfeld) quantization rules. We express this spectrum in a manner consistent with the method of scaled-variable spectroscopy, and then calculate the Fourier transform. These calculated absorption spectra and recurrence spectra are in good agreement with experiments on Li atoms. …


The Virginia Wetlands Report Vol. 13, No. 1, Virginia Institute Of Marine Science Mar 1998

The Virginia Wetlands Report Vol. 13, No. 1, Virginia Institute Of Marine Science

Virginia Wetlands Reports

  • Northern Pintail. Julie G. Bradshaw
  • Sheepshead Minnow. Lyle Varnell
  • Classifying Satellite Imagery to Detect Land Cover Features. Marcia Berman
  • Monitoring Wetlands Status and Trends: The Remote Sensing Solution. Carl Hershner
  • Roof Thatching: Phragmites as a Building Material. Pam Mason
  • Are nonvegetated, muddy shorelines valuable to the health of the Chesapeake Bay? William Roberts


Status Of The Major Oyster Diseases In Virginia 1997 A Summary Of The Annual Monitoring Program, Lisa M. Ragone Calvo, Eugene M. Burreson Mar 1998

Status Of The Major Oyster Diseases In Virginia 1997 A Summary Of The Annual Monitoring Program, Lisa M. Ragone Calvo, Eugene M. Burreson

Reports

No abstract provided.


1998 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans Jan 1998

1998 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.


1998 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans Jan 1998

1998 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.


1998 Wachapreague Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans Jan 1998

1998 Wachapreague Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.


Temporal Variability In Dissolved Organic Carbon And Radiocarbon In The Eastern North Pacific Ocean, James E. Bauer Jan 1998

Temporal Variability In Dissolved Organic Carbon And Radiocarbon In The Eastern North Pacific Ocean, James E. Bauer

VIMS Articles

The factors regulating the steady state inventories and residence times of dissolved organic carbon (DOG) in the deep ocean are not well established. Previous studies of DOC have been limited to single time-point profiles that provide general information on the potential role of vertical advective-diffusive processes in controlling DOC distributions and mean apparent ages. We present results from a 2-year time series station in the eastern North Pacific (station M) where short-term (months) changes in inventories and Delta(14)C signatures of DOC as measured in deep profiles were examined in conjunction with changes in particulate organic carbon (POC) pools. Significant long-term …


Submarine Sand Resources, Southeastern Virginia - Contributions From Year Nine And Year Ten Of Virginia’S Continental Margins Program, Carl Hobbs Iii, C. Scott Hardaway Jr., C. R. Berquist Jan 1998

Submarine Sand Resources, Southeastern Virginia - Contributions From Year Nine And Year Ten Of Virginia’S Continental Margins Program, Carl Hobbs Iii, C. Scott Hardaway Jr., C. R. Berquist

VIMS Books and Book Chapters

Virginia’s Year-Nine and Year-Ten funds from the Continental Shelf Program were used to supplement other work funded by the Minerals Management Service in an ongoing Cooperative Agreement focused on the area offshore of southeastern Virginia. Year-Nine and Year-Ten funds facilitated interpretation of subbottom profiles and the analysis of sediment samples from cores and grabs. On Virginia’s sediment-starved continental shelf, deposits of material potentially suitable for use as beach nourishment or, perhaps, as construction aggregate occur in three stratigraphic settings, each with specific characteristics of morphology, grain-size gradients, likelihood of discovery, and physical ease of exploitation. All must be verified with …


Hydrodynamics And Equilibrium Sediment Dynamics Of Shallow, Funnel-Shaped Tidal Estuaries, Carl T. Friedrichs, Bruce A. Armbrust, H. E. Deswart Jan 1998

Hydrodynamics And Equilibrium Sediment Dynamics Of Shallow, Funnel-Shaped Tidal Estuaries, Carl T. Friedrichs, Bruce A. Armbrust, H. E. Deswart

VIMS Books and Book Chapters

No abstract provided.


Remote Characterization Of Wetland Vegetation And Corresponding Relationship To Soils : Final Report On The Evaluation Of Imagery-Derived Terrain Attributes In The Coastal Zone, John E. Anderson, James E. Perry, Jill Meyer Jan 1998

Remote Characterization Of Wetland Vegetation And Corresponding Relationship To Soils : Final Report On The Evaluation Of Imagery-Derived Terrain Attributes In The Coastal Zone, John E. Anderson, James E. Perry, Jill Meyer

Reports

To accomplish the goals of this study, a pristine coastal barrier island environment was selected that was free from influences of urban development. This provided the optimal situation that could be expected to be encountered by military strategists and base resource managers. The site selected was Parramore Island (Figure I). Parramore Island is the seventh island ( north to south) located on the seaward margin of the southeastern Delmarva Peninsula and is one of the most dynamic and least disturbed coastal landscapes remaining in North America (McCaffrey and Dueser, 1990). The island is centered at Latitude 37° 30' and Longitude …


Chemical Interaction Of "Declorane Plus" With Antimony Trioxide In Nylon 66, Yum Min Kang Jan 1998

Chemical Interaction Of "Declorane Plus" With Antimony Trioxide In Nylon 66, Yum Min Kang

Dissertations, Theses, and Masters Projects

No abstract provided.


A Framework For Planning Sustainable Development In Coastal Regions: An Island Pilot Project In Croatia, Anamarija Frankic Jan 1998

A Framework For Planning Sustainable Development In Coastal Regions: An Island Pilot Project In Croatia, Anamarija Frankic

Dissertations, Theses, and Masters Projects

There have been few empirical studies demonstrating how sustainable development has been realized in a specific regime. This project developed and tested a framework for comprehensive planning including environmental, social, and economic considerations on the island Cres in the Croatian Coastal Zone. The approach defines sustainable development in coastal regions, and develops a generic framework incorporating biological, geological, chemical, physical, social, and economic factors necessary for sustainable development. The generic framework ensures that planning decisions will be based on environmental concerns of the area. A prime principle of the approach is that any plan must work with the environmental limits …


Distribution, Partitioning And Fluxes Of Dissolved And Particulate Organic Carbon, Nitrogen And Phosphorus In The Eastern North Pacific And Southern Oceans, Ai Ning Loh Jan 1998

Distribution, Partitioning And Fluxes Of Dissolved And Particulate Organic Carbon, Nitrogen And Phosphorus In The Eastern North Pacific And Southern Oceans, Ai Ning Loh

Dissertations, Theses, and Masters Projects

No abstract provided.


Calcium As A Limiting Factor In The Distribution Of The Amphipod Gammarus Pseudolimnaeus, John Kinsley Zehmer Jan 1998

Calcium As A Limiting Factor In The Distribution Of The Amphipod Gammarus Pseudolimnaeus, John Kinsley Zehmer

Dissertations, Theses, and Masters Projects

No abstract provided.


Selective Selenoxide Elimination On The Secondary Face Of Beta-Cyclodextrin, Ahmed M. Hafez Jan 1998

Selective Selenoxide Elimination On The Secondary Face Of Beta-Cyclodextrin, Ahmed M. Hafez

Dissertations, Theses, and Masters Projects

No abstract provided.


Searches For Exotic Matter, David Lee Morgan Jan 1998

Searches For Exotic Matter, David Lee Morgan

Dissertations, Theses, and Masters Projects

This research encompasses two quite distinct searches for exotic matter. The first half concerns exotic matter on the scale of elementary particles. In this chapter, I consider the production of gluinos, the supersymmetric partner of the gluon, in models where the gluino is very light. Cross sections are calculated for electroproduction and hadroproduction of gluinos and the results indicate that existing accelerators are capable of probing the region of gluino masses between 1.0 and 2.0GeV with lifetimes between 10{dollar}\sp{lcub}-10{rcub}{dollar} and 10{dollar}\sp{lcub}-6{rcub}{dollar} seconds. Such experiments could find a light gluino if it exists, or to close this unexplored mass-lifetime window. The …


Determination Of Trace Levels Of Lead In Whole Blood By Graphite Furnace Atomic Absorption Spectroscopy, Leslie A. Sombers Jan 1998

Determination Of Trace Levels Of Lead In Whole Blood By Graphite Furnace Atomic Absorption Spectroscopy, Leslie A. Sombers

Dissertations, Theses, and Masters Projects

No abstract provided.


Development Of A Quantitative Competetive Polymerase Chain Reaction Assay For The Detection And Quantitation Of Perkinsus Marinus In Oyster Tissues And Environmental Water Samples, Heather A. Yarnall Jan 1998

Development Of A Quantitative Competetive Polymerase Chain Reaction Assay For The Detection And Quantitation Of Perkinsus Marinus In Oyster Tissues And Environmental Water Samples, Heather A. Yarnall

Dissertations, Theses, and Masters Projects

No abstract provided.


The Effects Of Increased Inundation And Wrack Deposition On Photosynthesis And Respiration In A Virginia Salt Marsh, W. David Miller Jan 1998

The Effects Of Increased Inundation And Wrack Deposition On Photosynthesis And Respiration In A Virginia Salt Marsh, W. David Miller

Dissertations, Theses, and Masters Projects

No abstract provided.