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1998

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Articles 31 - 60 of 2339

Full-Text Articles in Physical Sciences and Mathematics

Magnetic Microstructure Of Magnetotactic Bacteria By Electron Holography, Rafal E. Dunin-Borkowski, Martha R. Mccartney, Richard B. Frankel, Dennis A. Bazylinski, Mihály Pósfai, Peter R. Buseck Dec 1998

Magnetic Microstructure Of Magnetotactic Bacteria By Electron Holography, Rafal E. Dunin-Borkowski, Martha R. Mccartney, Richard B. Frankel, Dennis A. Bazylinski, Mihály Pósfai, Peter R. Buseck

Physics

Off-axis electron holography in the transmission electron microscope was used to correlate the physical and magnetic microstructure of magnetite nanocrystals in magnetotactic bacteria. The magnetite crystals were all single magnetic domains, and the magnetization directions of small superparamagnetic crystals were constrained by magnetic interactions with larger crystals in the chains. Shape anisotropy was found to dominate magnetocrystalline anisotropy in elongated crystals. A coercive field between 300 and 450 oersted was determined for one chain.


New Caribbean Locality For The Extinct Great White Shark Carcharodon, Clare Flemming, Donald A. Mcfarlane Dec 1998

New Caribbean Locality For The Extinct Great White Shark Carcharodon, Clare Flemming, Donald A. Mcfarlane

WM Keck Science Faculty Papers

Carcharodon is represented by a single upper tooth (Fig. 1) which we extracted from the eroding Pliocene limestone wall, some six meters above the floor at the northern end of Darby Sink. Much of the tooth is missing, but the remaining portion includes features diagnostic of this genus. The tooth conforms in size and morphology to Carcharodon megalodon (Agassiz, 1843), an extinct great white shark.


The John Muir Newsletter, Winter 1998/99, The John Muir Center For Regional Studies Dec 1998

The John Muir Newsletter, Winter 1998/99, The John Muir Center For Regional Studies

Muir Center Newsletters (1981-2015)

NEWSLETTER Winter 1998-99 The Importance of John Muir's First Public Lecture, Sacramento, 1876 by Steve Pauly, Pleasant Hill, CA INTRODUCTION his article focuses on Muir's first public lecture and its importance as one of several turning points in his evolution as a public figure. The venue was the Congregational Church in Sacramento on January 25, 1876. The lecture was the fifth in a series sponsored by the Sacramento Literary Institute. Muir approached this task with fear, began poorly and with apology, finally recalled his topic, enthralled the large audience with his discussion and illustration of the current and ancient glaciers …


Observations On Groundwater Recharge In The Westdale Catchment, M F. Lewis, C E. Mcconnell Dec 1998

Observations On Groundwater Recharge In The Westdale Catchment, M F. Lewis, C E. Mcconnell

Resource management technical reports

A study of the role of groundwater carriers and barriers in controlling salinity was carried out in the Westdale Catchment by Lewis and McConnell (in preparation). Although that study was primarily concerned with groundwater flow and discharge processes, the data collected also provided rudimentary information on the timing of groundwater recharge events and their distribution across the landscape.


A Second Pre-Wisconsinan Locality For The Extinct Jamaican Rodent, Clidomys (Rodentia: Heptaxodontidae), Donald A. Mcfarlane, Joyce Lundberg, Clare Flemming, Ross D. E. Macphee, Stein-Erik Lauritzen Dec 1998

A Second Pre-Wisconsinan Locality For The Extinct Jamaican Rodent, Clidomys (Rodentia: Heptaxodontidae), Donald A. Mcfarlane, Joyce Lundberg, Clare Flemming, Ross D. E. Macphee, Stein-Erik Lauritzen

WM Keck Science Faculty Papers

Clidomys is the most distinctive but least well known member of the late Quaternary terrestrial mammal fauna of Jamaica. Here we report the second dated locality for this genus. The Illinoisan age we report further strengthens arguments we have made elsewhere, that Clidomys represents an early - probably pre-Wisconsinan - extinction that contrasts with the growing record of Holocene extinctions in the Antilles.


Future Directions For The Rock Lobster Industry Advisory Committee And The Western Rock Lobster Managed Fishery, Kevin Donohue Dec 1998

Future Directions For The Rock Lobster Industry Advisory Committee And The Western Rock Lobster Managed Fishery, Kevin Donohue

Fisheries Management Papers

This paper is divided into two parts. The purpose of Part One is to get Industry's views on the six key questions concerning the Rock Lobster Industry Advisory Committee's role, operation and advice. The purpose of Part Two is to present those management issues identified at the joint RLIAC/Western Rock Lobster Development Association workshop held on the 16 September 1998.


Future Directions For Tourism At The Houtman Abrolhos Islands - Draft For Public Comment, Le Provost Dames & Moore Dec 1998

Future Directions For Tourism At The Houtman Abrolhos Islands - Draft For Public Comment, Le Provost Dames & Moore

Fisheries Management Papers

This paper discusses the constraints on tourism in the Abrolhos and key management strategies of the draft tourism plan. Discusses facilities required and recommending a broadening of air services to allow their use for tourism, establishment of boat moorings for commercial tourist operators, public moorings may be installed and rented for use by private boats, upgrading of facilites Dransfield House on Beacon Island, could be used as an interpretive centre.


Management Plan For Sustainable Tourism At The Houtman Abrolhos Islands, Le Provost Dames & Moore Dec 1998

Management Plan For Sustainable Tourism At The Houtman Abrolhos Islands, Le Provost Dames & Moore

Fisheries Management Papers

The combination of unique species of fish, coral reefs and other invertebrates, historical shipwrecks and the commercially valuable Western rock lobster makes the Abrolhos a unique area of Western Australia. In recognition of this the Minister of Fisheries is releasing the plan 'Management of Houtman Abrolhos System', following a period of public consultation. The islands are becoming increasingly popular destination for tourists that are attracted to the diving, fishing, bird watching, maritime history and other features of the Abrolhos. The draft Management Plan for Sustainable Tourism in the Houtman Abolhos Islands has been developed to provide a framework within which …


Management Of The Houtman Abrolhos System., Kim Nardi, Abrolhos Islands Management Advisory Committee Dec 1998

Management Of The Houtman Abrolhos System., Kim Nardi, Abrolhos Islands Management Advisory Committee

Fisheries Management Papers

The Abrolhos System is the Houtman Abrolhos Islands and adjoing State Territorial Waters. It is an important part of the Western Australian environment. Has major significance in conservation of flora and fauna and also in geological terms. The waters adjoining State Territorial Waters contain some of the most highly valued marine systems in the State. These include sites of historical shipwrecks in Australia. The are of great interest to visitors and support a relatively small but growing recreation and tourism industy.

The area is integral to the Western rock lobster fishery, which is that State's premier primary industries. The Abrolhos …


Highline Breaks Watershed [Microform] : Otero County, Colorado, Pueblo County, Colorado : Watershed Plan And Environmental Assessment, United States Natural Resources Conservation Service, Colorado State Soil Conservation Board Dec 1998

Highline Breaks Watershed [Microform] : Otero County, Colorado, Pueblo County, Colorado : Watershed Plan And Environmental Assessment, United States Natural Resources Conservation Service, Colorado State Soil Conservation Board

Environmental Assessments (NV)

No abstract provided.


Relaxational Mode Structure For Optical Probe Diffusion In High Molecular Weight Hydroxypropylcellulose, Kiril A. Streletzky, George D.J. Phillies Dec 1998

Relaxational Mode Structure For Optical Probe Diffusion In High Molecular Weight Hydroxypropylcellulose, Kiril A. Streletzky, George D.J. Phillies

Physics Faculty Publications

We studied translational diffusion of dilute monodisperse spheres (diameters 14 < d < 455 nm) in aqueous 1 MDa hydroxypropylcellulose (0 ≤ c ≤ 7 g/L) at 25°C using quasielastic light scattering. Spectra are highly bimodal. The two spectral modes (“slow,” “fast”) have different physical properties. Probe behavior differs between small (d < Rh) and large (d ≥ Rg) probes; Rh and Rg are the matrix polymer hydrodynamic radius and the radius of gyration, respectively. We examined the dependences of spectral lineshape parameters on d, c, scattering vector q, and viscosity η for all four probe-size and mode-type combinations. We find three time scale-separated modes: (1) a large-probe slow mode has properties characteristic of particle motion in a viscous medium; (2) a large-probe fast mode and small-probe slow modes share the same time scale, and have properties characteristic of probe motion coupled to internal chain dynamics; and (3) a small-probe fast mode has properties that can be attributed to the probe sampling local chain relaxations. In the analysis, we also attempted to apply the coupling/scaling (CS) model of Ngai and Phillies [Ngai, K. L., Phillies, G. D. J. J. Chem. Phys.,105, 8385 (1996)] to analyze our data. We find that the second mode is described by the coupling/scaling model for probe diffusion; the first and third modes do not follow the predictions of this model.


A Quantitative Analysis Of Interstitial Fluid-Chemistry And Limestone Dissolution Rates Within The Clastic Sediment Of A Karst Aquifer Conduit, Mammoth Cave, Kentucky, Kevin Vaughan Dec 1998

A Quantitative Analysis Of Interstitial Fluid-Chemistry And Limestone Dissolution Rates Within The Clastic Sediment Of A Karst Aquifer Conduit, Mammoth Cave, Kentucky, Kevin Vaughan

Masters Theses & Specialist Projects

Many active stream conduits within karst aquifers transport and deposit non-carbonate, clastic sediment. However, little is known about how these sediments impact conduit development and enlargement rates. For example, can dissolution take place at the sediment/bedrock interface beneath a flowing stream? If not, cavern enlargement might be dominated by flood conditions when the bare rock of the walls and ceiling are in contact with the dissolving fluids. An approach using limestone tablet weight loss experiments, along with water sampling and geochemical modeling, has been undertaken to understand the nature of fluid movement and chemistry with the sediment beneath an active …


Optimizing Amplifier Placements In A Multiwavelength Optical Lan/Man: The Unequally Powered Wavelengths Case, Byrav Ramamurthy, Jason Iness, Biswanath Mukherjee Dec 1998

Optimizing Amplifier Placements In A Multiwavelength Optical Lan/Man: The Unequally Powered Wavelengths Case, Byrav Ramamurthy, Jason Iness, Biswanath Mukherjee

School of Computing: Faculty Publications

Optical networks based on passive-star couplers and employing WDM have been proposed for deployment in local and metropolitan areas. These networks suffer from splitting, coupling, and attenuation losses. Since there is an upper bound on transmitter power and a lower bound on receiver sensitivity, optical amplifiers are usually required to compensate for the power losses mentioned above. Due to the high cost of amplifiers, it is desirable to minimize their total number in the network. However, an optical amplifier has constraints on the maximum gain and the maximum output power it can supply; thus, optical amplifier placement becomes a challenging …


Excitation Efficiency Of A Morphology-Dependent Resonance By A Focused Gaussian Beam, James A. Lock Dec 1998

Excitation Efficiency Of A Morphology-Dependent Resonance By A Focused Gaussian Beam, James A. Lock

Physics Faculty Publications

The excitation efficiency of a morphology-dependent resonance (MDR) by an incident beam is defined as the fraction of the beam power channeled into the MDR. The efficiency is calculated for a focused Gaussian beam of arbitrary width incident on either a spherical particle or a cylindrical fiber located at an arbitrary position in the plane of the beam waist. In each case a simple formula for the efficiency is derived by use of the localized approximation for the beam-shape coefficients in the partial-wave expansion of the beam. The physical interpretation of the efficiency formulas is also discussed. (C) 1998 Optical …


Year In Review - 1998, Annis Water Resources Institute Dec 1998

Year In Review - 1998, Annis Water Resources Institute

AWRI Reviews

No abstract provided.


Fan-Type Conditions For Collapsible Graphs, Zhi-Hong Chen Dec 1998

Fan-Type Conditions For Collapsible Graphs, Zhi-Hong Chen

Scholarship and Professional Work - LAS

No abstract provided.


Notes From The Director, The Mcnair Team Dec 1998

Notes From The Director, The Mcnair Team

McNair Scholars Research Journal

No abstract provided.


A Portable, Object-Oriented Library For Neural Network Simulation, Martin P. Franz Dec 1998

A Portable, Object-Oriented Library For Neural Network Simulation, Martin P. Franz

Masters Theses

A portable, object-oriented library for simulation of general Multi-layer Feedforward Neural Networks (MLFNs) is described. Unlike all-encompassing neural network simulation environments, the library was designed to allow convenient use in existing programs and in applications where training and testing data are generated using separate, often complex simulations.

The library' s design goals include modularity, portability, efficiency, correctness, compactness, and type-safety. To demonstrate how these objectives are met, competing architectural choices are presented, along with the criteria used for determining the strategy actually implemented. Sample applications using the library are presented, showing how the library' s class files are used in …


Experiments To Maximize Growth In Captive Florida Pompano (Trachinotus Carolinus), Brian J. Hicks Dec 1998

Experiments To Maximize Growth In Captive Florida Pompano (Trachinotus Carolinus), Brian J. Hicks

HCNSO Student Theses and Dissertations

Florida pompano (Trachinotus carolinus) are highly prized food and sport fish indigenous to coastal areas of the southeastern United States. A commercially valuable fishery has historically existed in the Gulf of Mexico and on the South Atlantic seaboard. Efforts to economically culture Florida pompano in a captive environment were only partially successful. Four experiments were performed to explore the physical and environmental requirements of Florida pompano and other closely related species in the Family (Carangidae):

Experiment #1- Semi-natural spawning was induced with newly developed hormonal implants. to initiate and sustain semi-natural spawning in captive Florida pompano. Fish collected from the …


Closed-Loop Object Recognition Using Reinforcement Learning, Jing Peng, Bir Bhanu Dec 1998

Closed-Loop Object Recognition Using Reinforcement Learning, Jing Peng, Bir Bhanu

Department of Computer Science Faculty Scholarship and Creative Works

Current computer vision systems whose basic methodology is open-loop or fi'/tertype typically use image segmentation followed by object recognition algorithms. These systems are not robust for most real-world applications. In contrast the system presented here achieves robust performance by using reinforcement learning to induce a mapping from input images to corresponding segmentation parameters. This is accomplished by using the confidence level of model matching as a reinforcement signal for a team of learning automata to search for segmentation parameters during training. The use of the recognition algorithm as part of the evaluation function for image segmentation gives rise to significant …


Acknowledgements, The Mcnair Team Dec 1998

Acknowledgements, The Mcnair Team

McNair Scholars Research Journal

No abstract provided.


The Prairie Naturalist Volume 30, No.4 December 1998 Dec 1998

The Prairie Naturalist Volume 30, No.4 December 1998

The Prairie Naturalist

FISH COMMUNITY AND WATER QUALITY CHANGES IN THE BIG SIOUX RIVER ▪ D. Dieterman, and C. R. Berry, Jr.

EFFECTS OF PARASITOIDS AND COMPETITION ON CLUTCH SIZE OF A GALLING MIDGE ▪ D. J. Kinateder and S. J. Stein

RESPONSE OF BREEDING SEASON BLUE-WINGED TEAL TO DECOY TRAPPING ▪ P. R. Garrettson

COMPARISON OF POINT-COUNT AND WADE-FLUSH METHODS FOR COUNTING DUCKS ▪ G. M. Linz, C. P McMurl, H. J. Homan, and D. L. Bergman

Reviewers 1998

Author Index - Volume 30

Subject Index - Volume 30

Announcements


Capillary Zone Electrophoresis Studies Of Sulfur Containing Compounds, Francisco Rodriguez Dec 1998

Capillary Zone Electrophoresis Studies Of Sulfur Containing Compounds, Francisco Rodriguez

Masters Theses & Specialist Projects

Up to this point in time, complex mixtures of tertiary sulfonium ions have been separated or analyzed employing conventional methods like HPLC or NMR procedures. In this thesis the researcher presents a new approach, the use of Capillary Zone Electrophoresis (CZE) for the analysis of these types of ions as well as the closely related thiophenium ions. CZE offers an unprecedented advantage in that separations can be employed for speciation or quantitation of complex mixtures by using the appropriate standards or specific detectors. For the study, model sulfonium and thiophenium ions were used to determine the feasibility of the separation …


The Probe, Issue 195 – December 1998 Dec 1998

The Probe, Issue 195 – December 1998

The Probe: Newsletter of the National Animal Damage Control Association

Rabies -- Mike Dwyer, NADCA Director, Great Lakes Region
Position Available: Wildlife Biologist, JFK Airport
NWCO Organization Forms in Calif.
Update on Idaho Wolf Damage
Wildlife Wins in UT, OH, MN, Loses in CA
Schmidt to be Appointed NADCA President
Rabies in Bats: The following article was authored by Kate Lewandowski and is reprinted with permission from "SCWDS Briefs," the quarterly newsletter of the Southeastern Cooperative Wildlife Disease Study, The University of Georgia, Athens, GA.

Bird-Strike Committee -USA Abstracts

CANADA GEESE AND SNOW GEESE – REASSESSING TRADITIONAL PARADIGMS FOR MANAGEMENT -- Robert Blohm, U.S. Fish & Wildlife Service, Migratory Bird …


Effect Of Ammonia Flow Rate On Impurity Incorporation And Material Properties Of Si-Doped Gan Epitaxial Films Grown By Reactive Molecular Beam Epitaxy, Wook Kim, A. E. Botchkarev, H. Morkoç, Z-Q. Fang, David C. Look, David J. Smith Dec 1998

Effect Of Ammonia Flow Rate On Impurity Incorporation And Material Properties Of Si-Doped Gan Epitaxial Films Grown By Reactive Molecular Beam Epitaxy, Wook Kim, A. E. Botchkarev, H. Morkoç, Z-Q. Fang, David C. Look, David J. Smith

Physics Faculty Publications

Effect of ammonia flow rate on the impurity incorporation and material properties of Si-doped GaN films grown by reactive molecular beam epitaxy (RMBE) process is discussed. It appears that the ammonia flow rate has a marginal effect on the incorporation of impurities into the Si-doped GaN films except there was a little decrease in O and Si with increasing ammonia flow rate when the Si concentration in the film is higher than 1018 cm−3. Electron Hall mobility of Si-doped GaN films grown by RMBE varies with ammonia flow rate used during film growth. From deep level transient …


Phorbol 12-Myristate 13-Acetate Stimulates Lysophosphatidic Acid Secretion From Ovarian And Cervical Cancer Cells But Not From Breast Or Leukemia Cells, Zhongzhou Shen, Jerome Belinson, Richard E. Morton, Yan Xu Dec 1998

Phorbol 12-Myristate 13-Acetate Stimulates Lysophosphatidic Acid Secretion From Ovarian And Cervical Cancer Cells But Not From Breast Or Leukemia Cells, Zhongzhou Shen, Jerome Belinson, Richard E. Morton, Yan Xu

Chemistry Faculty Publications

Lysophosphatidic acid (LPA) is present in ascites from patients with ovarian cancer. It stimulates calcium release and growth of ovarian cancer cells bothin vitroandin vivo.Recently, we found that LPA levels were significantly elevated in plasma from patients with ovarian cancer and other gynecological cancers. In contrast, LPA levels were not elevated in patients with breast cancer and leukemias. In view of this, we investigated whether gynecological cancer cells could produce LPA. LPA was extracted from the supernatant of cells culturedin vitroand purified by thin layer chromatography. After hydrolysis and transmethylation, the fatty acid derivatives were analyzed by gas chromatography. We …


Nickel Subsulfide Can Protect Human Fibroblasts From The Mutagenic Effect Of Benzo[A]Pyrene Diolepoxide, Samir M. Hamdan Dec 1998

Nickel Subsulfide Can Protect Human Fibroblasts From The Mutagenic Effect Of Benzo[A]Pyrene Diolepoxide, Samir M. Hamdan

Masters Theses

Cancer researchers are interested in identifying the environmental causes and synergistic influences of different carcinogens. It is important to examine the combined effect of multiple carcinogens since this is a more realistic representation of the true environmental situation in which we are exposed daily. Our study has reported that pretreating human fibroblasts with nickel subsulfide followed by the simultaneous treatment with both nickel subsulfide and benzo[a]pyrene diolepoxide (BPDE) can protect human fibroblasts from the mutagenic effects of BPDE. These results correlate well with our previous chromium-BPDE co-treatment work, suggesting a transition metal dependent protective effect. This protective effect was dependent …


Synthesis, Characterization And Photophysical Behavior Of A Cr(Iii) Bimetallic System, Yan Chen Dec 1998

Synthesis, Characterization And Photophysical Behavior Of A Cr(Iii) Bimetallic System, Yan Chen

Masters Theses

Many binuclear transition metal complexes have been studied to understand the nature of interactions between the metal centers. People have found Simultaneous Pair Excitation phenomenon in some bimetallic system that can serve as a potential source of Non-Linear Optical behavior.

Thus a series of Cr2 -([14]aneN4)2-X4n+ complexes were synthesized and characterized. Only the cis,cis configuration was found. The results were compared with those of their monomer analogs. The electronic structures are very similar in both monomer and dimer complexes. The quantum yield, UV-Vis absorption and lifetime studies suggested a possible coupling between the …


Application Of The Paleomagnetic Fold Test To Determine The Relative Timing Of Sill Intrusion And Deformation In The Southwest Helena Salient, Montana, Stephen Christopher Whisner Dec 1998

Application Of The Paleomagnetic Fold Test To Determine The Relative Timing Of Sill Intrusion And Deformation In The Southwest Helena Salient, Montana, Stephen Christopher Whisner

Masters Theses

The Doherty Mountain fold complex is a highly folded and faulted region along the southern boundary of the Helena Salient in southwestern Montana. This region has a complex deformation history that is a key to deformation within the Helena Salient as a whole. A structural interpretation of the deformed rocks of this area was conducted using field mapping and cross section construction at 1:24,000 scale providing insight to the internal deformation processes involved. Fourteen folds and three major faults were mapped and analyzed showing the influence of the Southwest Montana Transverse Zone and late stage detachment faulting on fold orientation. …


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 14, Number 9, December 1998, College Of Engineering And Computer Science, Wright State University Dec 1998

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 14, Number 9, December 1998, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.