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1995

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Articles 2071 - 2100 of 2193

Full-Text Articles in Physical Sciences and Mathematics

The Complexities Of Decision-Making Related To Health Risk Assessments, Barbara A. Knuth Jan 1995

The Complexities Of Decision-Making Related To Health Risk Assessments, Barbara A. Knuth

Maine Policy Review

Maine, like the nation, has focused a great deal of recent attention on determining acceptable levels of environmental and human health risk. Barbara discusses the role and uses of scientific information in risk assessment and public policy debate. Similar to Kevin Boyle's previous article (featured in the December 1994 issue of Maine Policy Review), Knuth discusses the 1992 Maine Board of Environmental Protection hearings which focused on the human consumption of fish potentially contaminated with dioxin.

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Optimizing Object Invocation Using Optimistic Incremental Specialization, Jon Inouye, Andrew P. Black, Charles Consel, Calton Pu, Jonathan Walpole Jan 1995

Optimizing Object Invocation Using Optimistic Incremental Specialization, Jon Inouye, Andrew P. Black, Charles Consel, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

To make object invocation efficient, it is important to minimize overhead. In general, overhead is incurred in order to maintain transparency; with the advent of mobile computer systems, persistence, increasing security and privacy concerns, transparency becomes more expensive and overhead is increasing. Invocation mechanisms maintain transparency by finding objects, choosing communication media, performing data translation into common formats (e.g., XDR), marshalling arguments, encrypting confidential data, etc. Performing all of these operations on every invocation would lead to unacceptable performance, so designers often avoid operations by specializing object invocation for more restricted environments. For example, the Emerald compiler performs several optimizations …

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Management Plan For Sea Turtles And Marine Mammals In Virginia, The Virginia Sea Turtle/Marine Mammal Conservation Team Jan 1995

Management Plan For Sea Turtles And Marine Mammals In Virginia, The Virginia Sea Turtle/Marine Mammal Conservation Team

Reports

No abstract provided.

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Production Of Excited Beauty States In Z Decays, D. Buskulic, Manoj Thulasidas Jan 1995

Production Of Excited Beauty States In Z Decays, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A data sample of about 3.0 million hadronic Z decays collected by the ALEPH experiment at LEP in the years 1991 through 1994, is used to make an inclusive selection of B hadron events.

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First Measurement Of The Quark-To-Photon Fragmentation Function, D. Buskulic, Manoj Thulasidas Jan 1995

First Measurement Of The Quark-To-Photon Fragmentation Function, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

Earlier measurements at LEP of isolated hard photons in hadronic Z decays, attributed to radiation from primary quark pairs, have been extended in the ALEPH experiment to include hard photon production inside hadron jets. Events are selected where all particles combine democratically to form hadron jets, one of which contains a photon with a fractional energy z 0:7. After statistical subtraction of non-prompt photons, the quark-to-photon fragmentation function, D(z), is extracted directly from the measured 2-jet rate. By taking into account the perturbative contributions to D(z) obtained from an O(S ) QCD calculation, the unknown non-perturbative component of D(z) is …

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Inclusive Production Of Neutral Vector Mesons In Hadronic Z Decays, D. Buskulic, Manoj Thulasidas Jan 1995

Inclusive Production Of Neutral Vector Mesons In Hadronic Z Decays, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

Data on the inclusive production of the neutral vector mesonsρ 0(770),ω(782), K*0(892), andφ(1020) in hadronic Z decays recorded with the ALEPH detector at LEP are presented and compared to Monte Carlo model predictions. Bose-Einstein effects are found to be important in extracting a reliable value for theρ 0 production rate. An averageρ 0 multiplicity of 1.45±0.21 per event is obtained. Theω is detected via its three pion decay modeω→π + π − π 0 and has a total rate of 1.07±0.14 per event. The multiplicity of the K*0 is 0.83±0.09, whilst that of theφ is 0.122±0.009, both measured using their …

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Improved Tau Polarisation Measurement, D. Buskulic, M. Thulasidas Jan 1995

Improved Tau Polarisation Measurement, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

Using 22 pb−1 of data collected at LEP in 1992 on the peak of the Z resonance, the ALEPH collaboration has measured the polarisation of the tau leptons decaying intoevv¯,μvv¯evv¯,μvv¯,πν, ρν and a1 ν from their individual decay product distributions. The measurement of the tau polarisation as a function of the production polar angle yields the two parametersN τ andN e, where, in terms of the axial and vector couplingsg Al andg Vl,N l=2g Vl gAl/(g 2Vl+g2Al). This analysis follows to a large extent the methods devised for the 1990 and 1991 data but with improvements which bring a better …

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Multiple Query Optimization With Depth-First Branch-And-Bound And Dynamic Query Ordering, Ee Peng Lim, Ahmet Cosar, Jaideep Srivastava Jan 1995

Multiple Query Optimization With Depth-First Branch-And-Bound And Dynamic Query Ordering, Ee Peng Lim, Ahmet Cosar, Jaideep Srivastava

Research Collection School Of Computing and Information Systems

In certain database applications such as deductive databases, batch query processing, and recursive query processing etc., usually a single query gets transformed into a set of closely related database queries. Also, great benefits can be obtained by executing a group of related queries all together in a single unified multi-plan instead of executing each query separately. In order to achieve this Multiple Query Optimization (MQO) identifies common task(s) (e.g. common subexpressions, joins, etc.) among a set of query plans and creates a single unified plan (multi-plan) which can be executed to obtain the required outputs for all queries at once. …

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Elimination Of Dissolved Sulfide Interference In The Flow-Injection Determination Of Sigma-Co2 By Addition Of Molybdate, Rigel L. Lustwerk, David J. Burdige Jan 1995

Elimination Of Dissolved Sulfide Interference In The Flow-Injection Determination Of Sigma-Co2 By Addition Of Molybdate, Rigel L. Lustwerk, David J. Burdige

OES Faculty Publications

A previously described flow injection method for the analysis of ΣCO2 included the addition of ZnCl2 to some samples before analysis in order to precipitate dissolved sulfide (which interferes with the method) as ZnS. However, the use of Zn2+ in samples with high concentrations of dissolved sulfide causes the coprecipitation of ZnCO3, and in our experience with this technique, ZnCO3 also precipitates even in the absence of dissolved sulfide. The addition of molybdate effectively complexes dissolved sulfide without interfering with the determination of ΣCO2 by this technique.

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A Logistic Model Of Periodic Chemotherapy, J. C. Panetta Jan 1995

A Logistic Model Of Periodic Chemotherapy, J. C. Panetta

Mathematics & Statistics Faculty Publications

A logistic differential equation with a time-varying periodic parameter is used to model the growth of cells, in particular cancer cells, in the presences of chemotherapeutic drugs. The chemotherapeutic effects are modeled by a periodic parameter that modifies the growth rate of the cell tissue. A negative growth rate represents the detrimental effects of the drugs. A simple criterion is obtained for the behavior of the chemotherapy.

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Fermi Problems: Educated Guesses, John A. Adam Jan 1995

Fermi Problems: Educated Guesses, John A. Adam

Mathematics & Statistics Faculty Publications

No abstract provided.

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Influence Of Zooplankton Grazing On Free Dissolved Enzymes In The Sea, Alexander B. Bochdansky, Staša Puškarić, Gerhard J. Herndl Jan 1995

Influence Of Zooplankton Grazing On Free Dissolved Enzymes In The Sea, Alexander B. Bochdansky, Staša Puškarić, Gerhard J. Herndl

OES Faculty Publications

In the Northern Adriatic Sea, extracellular enzymatic activity was measured during a Lagrangian study following a drifting buoy for 40 h. Dissolved free enzymatic activity represented 20 to 70% of total activity depending on the type of enzyme. alpha- and beta-glucosidases exhibited a significantly higher free activity than proteolytic enzymes. In subsequent laboratory experiments we investigated the effect of zooplankton on the free enzyme pool. The 4-step approach included: (1) determination of the enzymatic activities in copepods (mainly Acartia clausi); (2) enzymatic activity in fecal pellets; (3) short- and long-term grazing experiments; and (4) degradability of free glucosidase in seawater. …

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Time To Metamorphosis Of Blue Crab Callinectes Sapidus Megalopae: Effects Of Benthic Macroalgae, Robert D. Brumbaugh, John R. Mcconaugha Jan 1995

Time To Metamorphosis Of Blue Crab Callinectes Sapidus Megalopae: Effects Of Benthic Macroalgae, Robert D. Brumbaugh, John R. Mcconaugha

OES Faculty Publications

There is growing evidence that postlarvae (megalopae) of the blue crab Callinectes sapidus can slow the progression through the molt cycle while in offshore nursery grounds, and delay metamorphosis until reinvasion of coastal habitat occurs. However, the cues that trigger metamorphosis of megalopae are not well known. This study tested the hypothesis that the time to metamorphosis (TTM) from the postlarval megalops stage to the first crab stage is shortened in the presence of 2 potential macroalgal settlement substrates, Ulva lactuca (Chlorophyta), and Gracilaria spp. (Rhodophyta). Megalopae and test water were collected from 3 locations (offshore, at a coastal inlet, …

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Linear Time Optimization Algorithms For P4-Sparse Graphs, Beverly Jamison, Stephan Olariu Jan 1995

Linear Time Optimization Algorithms For P4-Sparse Graphs, Beverly Jamison, Stephan Olariu

Computer Science Faculty Publications

Quite often, real-life applications suggest the study of graphs that feature some local density properties. In particular, graphs that are unlikely to have more than a few chordless paths of length three appear in a number of contexts. A graph G is P4-sparse if no set of five vertices in G induces more than one chordless path of length three. P4-sparse graphs generalize both the class of cographs and the class of P4-reducible graphs. It has been shown that P4-sparse graphs can be recognized in time linear in the size of the …

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Water Resources : Planning For Future Demand In The York River Basin, Mel Vargas, Carl Hershner, Marcia Berman Jan 1995

Water Resources : Planning For Future Demand In The York River Basin, Mel Vargas, Carl Hershner, Marcia Berman

Reports

This report analyzes issues related to water supply and demand for the York River Basin (YRB) in Virginia.

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An Optimal Path Cover Algorithm For Cographs, R. Lin, S. Olariu Jan 1995

An Optimal Path Cover Algorithm For Cographs, R. Lin, S. Olariu

Computer Science Faculty Publications

The class of cographs, or complement-reducible graphs, arises naturally in many different areas of applied mathematics and computer science. In this paper, we present an optimal algorithm for determining a minimum path cover for a cograph G. In case G has a Hamiltonian path (cycle) our algorithm exhibits the path (cycle) as well.

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Immigration Variability And Post-Settlement Processes Of The Spiny Lobster, Panulirus Argus, In The Exuma Cays, Bahamas, Luis Coba-Cetina Jan 1995

Immigration Variability And Post-Settlement Processes Of The Spiny Lobster, Panulirus Argus, In The Exuma Cays, Bahamas, Luis Coba-Cetina

Dissertations, Theses, and Masters Projects

No abstract provided.

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Effects Of Sunlight And Seasonal Temperature On Persistence Of Four Bacteriophages In An Estuarine Environment, Terri A. Muller Jan 1995

Effects Of Sunlight And Seasonal Temperature On Persistence Of Four Bacteriophages In An Estuarine Environment, Terri A. Muller

Dissertations, Theses, and Masters Projects

No abstract provided.

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Osmotic Tolerance And Volume Regulation In Cultured Cells Of The Oyster Pathogen Perkinsus Marinus, Caroline L. O'Farrell Jan 1995

Osmotic Tolerance And Volume Regulation In Cultured Cells Of The Oyster Pathogen Perkinsus Marinus, Caroline L. O'Farrell

Dissertations, Theses, and Masters Projects

No abstract provided.

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Spawning And Ecology Of Early Life Stages Of Black Drum, Pogonias Cormis, In Lower Chesapeake Bay, Louis Broaddus Daniel Iii Jan 1995

Spawning And Ecology Of Early Life Stages Of Black Drum, Pogonias Cormis, In Lower Chesapeake Bay, Louis Broaddus Daniel Iii

Dissertations, Theses, and Masters Projects

During spring 1990 and 1991, ichthyoplankton surveys were conducted in lower Chesapeake Bay to estimate seasonal egg production, population biomass and the impact of predation by gelatinous zooplankton on early life stages of black drum, Pogonias cromis. Rearing experiments indicated that at least three species of sciaenid (silver perch, Bairdiella chrysoura; weakfish, Cynoscion regalis and P. cromis) were spawning in the survey area during both years. Specific identification of eggs based on previously published ranges of outside egg diameter (OED) were not reliable due to considerable overlap in diameter distributions. Analysis of weekly OED frequency revealed the presence of three …

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Occurrence, Fate And Effects Of Polychlorinated Terphenyls In An Estuarine Environment, Kathryn Gallagher Jan 1995

Occurrence, Fate And Effects Of Polychlorinated Terphenyls In An Estuarine Environment, Kathryn Gallagher

Dissertations, Theses, and Masters Projects

Aroclor 5432, a mixture of polychlorinated terphenyls (PCT), was detected in sediment and several biological compartments including: saltmarsh cordgrass (Spartina alterniflora), American oysters (Crassostrea virginica), red-jointed fiddler crabs (Uca minax), wharf crabs (Sesarma reticulatum) and mummichogs (Fundulus heteroclitus) collected from Tabbs Creek. This tidal creek is located in the southern Chesapeake Bay region. Species from several phyla were selected in order to examine PCT accumulation in physiologically and ecologically different organisms. In general, PCT concentrations in sediment and biota decreased with distance downstream from the PCT outfall. The organism with the highest mean concentration (18,300 &\mu&g/kg dry weight) was the …

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Acid Dissociation Of Chloroguaiacols And Ph Dependent Sorption To Estuarine Sediments, Jennifer Lisa Gundersen Jan 1995

Acid Dissociation Of Chloroguaiacols And Ph Dependent Sorption To Estuarine Sediments, Jennifer Lisa Gundersen

Dissertations, Theses, and Masters Projects

Chloroguaiacols are common components of bleached kraft pulp mill effluent known to bioaccumulate in aquatic organisms, and sorb onto particulate material and sediments. Ionization properties of the chloroguaiacols must be known in order to explain their sorptive behavior in aquatic systems. to obtain this information, thermodynamic acid dissociation constants (p&K\sb{lcub}\rm a{rcub})& of guaiacol (o-methoxyphenol) and nine chloroguaiacols have been determined by spectrophotometric methods. These experimental p&K\sb{lcub}\rm a{rcub}& values have been compared with literature values, values predicted by the Hammett equation and predictions by quantum chemical calculations using MOPAC 6.0 with AM1 and MNDO Hamiltonian operators. Experimental and predicted acidities were …

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Resuspension Behavior Of Natural Estuarine Sediments, Chang-Hee Lee Jan 1995

Resuspension Behavior Of Natural Estuarine Sediments, Chang-Hee Lee

Dissertations, Theses, and Masters Projects

The resuspension behavior of natural estuarine sediments was studied using the VIMS Sea Carousel, a benthic annular flume. The bed shear stresses produced by the flume were measured by a hot-film sensor mounted flush on the bottom of a laboratory version of the Carousel under a clear-water and flat-bottom condition. Measurements showed a reasonably uniform bed shear stress across the channel and agreed with the relationship &\tau\sb{lcub}\rm b{rcub}=0.011\Omega\sp{lcub}1.69{rcub},& where &\Omega& = ring speed (rpm) and &\tau\sb{lcub}\rm b{rcub}& = spatially-averaged bed shear stress (N/m&\sp2&), predicted from a previous numerical study. Thus, the &\tau\sb{lcub}\rm b{rcub}& was used as a bed shear stress …

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Effects Of Simulated Sediment Resuspension Events On The Abundance Of Water Column Bacteria Of Tomales Bay, California, Christopher J. Collumb Jan 1995

Effects Of Simulated Sediment Resuspension Events On The Abundance Of Water Column Bacteria Of Tomales Bay, California, Christopher J. Collumb

Dissertations, Theses, and Masters Projects

No abstract provided.

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A Comparison Of Three Wetland Evaluation Methods In Their Assessment Of Nontidal Wetlands In The Coastal Plain Of Virginia, Melissa Claire Chaun Jan 1995

A Comparison Of Three Wetland Evaluation Methods In Their Assessment Of Nontidal Wetlands In The Coastal Plain Of Virginia, Melissa Claire Chaun

Dissertations, Theses, and Masters Projects

No abstract provided.

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The Effects Of Hook Type On The Hooking Mortality Of Two Size Classes Of Summer Flounder, Paralichthys Dentatus, Tracy D. Holton Jan 1995

The Effects Of Hook Type On The Hooking Mortality Of Two Size Classes Of Summer Flounder, Paralichthys Dentatus, Tracy D. Holton

Dissertations, Theses, and Masters Projects

No abstract provided.

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Genetic Relationships Among Geographically Isolated Populations Of Bluefish (Pomatamus Saltatrix), Catherine N. O'Neill Jan 1995

Genetic Relationships Among Geographically Isolated Populations Of Bluefish (Pomatamus Saltatrix), Catherine N. O'Neill

Dissertations, Theses, and Masters Projects

No abstract provided.

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Crassostrea Virginica On Constructed Intertidal Oyster Reefs: The Effects Of Tidal Height And Substrate Level On Settlement, Growth, And Mortality, Ian K. Bartol Jan 1995

Crassostrea Virginica On Constructed Intertidal Oyster Reefs: The Effects Of Tidal Height And Substrate Level On Settlement, Growth, And Mortality, Ian K. Bartol

Dissertations, Theses, and Masters Projects

No abstract provided.

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High-Resolution Seismic Stratigraphy Of The Ganges-Brahmaputra River System: Subaqueous Deltaic Progradation On The Bengal Shelf, Beth Michele Levy Jan 1995

High-Resolution Seismic Stratigraphy Of The Ganges-Brahmaputra River System: Subaqueous Deltaic Progradation On The Bengal Shelf, Beth Michele Levy

Dissertations, Theses, and Masters Projects

No abstract provided.

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An Analysis Of Wetland Total Phosphorus Retention And Watershed Structure, Megan K. Greiner Jan 1995

An Analysis Of Wetland Total Phosphorus Retention And Watershed Structure, Megan K. Greiner

Dissertations, Theses, and Masters Projects

No abstract provided.

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