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1999

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Articles 451 - 480 of 2555

Full-Text Articles in Physical Sciences and Mathematics

Luminosity Profiles Of Merger Remnants, J E. Hibbard, Min S. Yun Aug 1999

Luminosity Profiles Of Merger Remnants, J E. Hibbard, Min S. Yun

Min S. Yun

Using published luminosity and molecular gas profiles of the late-stage mergers NGC 3921, NGC 7252, and Arp 220, we examine the expected luminosity profiles of the evolved merger remnants, especially in light of the massive CO complexes that are observed in their nuclei. For NGC 3921 and NGC 7252, we predict that the resulting luminosity profiles will be characterized by an r1/4 law. In view of previous optical work on these systems, it seems likely that they will evolve into normal elliptical galaxies as regards their optical properties. Due to a much higher central molecular gas column density, Arp 220 …


Detection Of Co (2-1) And Radio Continuum Emission From The Z = 4.4 Qso Bri 1335–0417, C L. Carilli, Karl M. Menten, Min S. Yun Aug 1999

Detection Of Co (2-1) And Radio Continuum Emission From The Z = 4.4 Qso Bri 1335–0417, C L. Carilli, Karl M. Menten, Min S. Yun

Min S. Yun

We have detected redshifted CO (2-1) emission at 43 GHz and radio continuum emission at 1.47 and 4.86 GHz from the z = 4.4 QSO BRI 1335-0417 using the Very Large Array. The CO data imply optically thick emission from warm (>30 K) molecular gas with a total mass, M(H2), of (1.5 ± 0.3) × 1011 Msun, using the standard Galactic gas mass-to-CO luminosity conversion factor. We set an upper limit to the CO source size of 1farcs1 and a lower limit of 0farcs23(Tex/50 K)-1/2, where Tex is the gas excitation temperature. We derive an upper limit to the …


An Evaluation Of Land Use Changes And Their Associated Hydrologic Impacts In The Birch Creek Watershed, Halifax County, Virginia 1986-1998, Melissa Anne Lloyd Aug 1999

An Evaluation Of Land Use Changes And Their Associated Hydrologic Impacts In The Birch Creek Watershed, Halifax County, Virginia 1986-1998, Melissa Anne Lloyd

Theses & Honors Papers

This project is a study of the water quality and land us e changes that have occurred in the Birch Creek watershed in Halifax County, Virginia from 1987 to 1998. The purpose of t his project i s to identify water quality trends and potential linkages to land use changes during the time frame of the study. The information was obtained by analyzing data collected by the Virginia Department of Environmental Quality. The data had been gathered and archived, but not previously examined for trends or causal factors. Through the analysis, definite increasing and decreasing trends in the concentrations of …


The Methionyl Aminopeptidase From Escherichia Coli Can Function As An Iron(Ii) Enzyme, Ventris M. D'Souza, Richard C. Holz Aug 1999

The Methionyl Aminopeptidase From Escherichia Coli Can Function As An Iron(Ii) Enzyme, Ventris M. D'Souza, Richard C. Holz

Chemistry Faculty Research and Publications

The identity of the physiologically relevant metal ions for the methionyl aminopeptidase (MetAP) from Escherichia coli was investigated and is suggested to be Fe(II). The metal content of whole cells in the absence and presence of expression of the type I MetAP from E. coli was determined by inductively coupled plasma (ICP) emission analysis. The observed change in whole cell concentrations of cobalt, cadmium, copper, nickel, strontium, titanium, and vanadium upon expression of MetAP was negligible. On the other hand, significant increases in the cellular metal ion concentrations of chromium, zinc, manganese, and iron were observed with the increase in …


1H Nmr Studies On The Cua Center Of Nitrous Oxide Reductase From Pseudomonas Stutzeri, Richard C. Holz, Marcela L. Alvarez, Walter G. Zumft, David M. Dooley Aug 1999

1H Nmr Studies On The Cua Center Of Nitrous Oxide Reductase From Pseudomonas Stutzeri, Richard C. Holz, Marcela L. Alvarez, Walter G. Zumft, David M. Dooley

Chemistry Faculty Research and Publications

1H NMR spectra of the CuA center of N2OR from Pseudomonas stutzeri, and a mutant enzyme that contains only CuA, were recorded in both H2O- and D2O-buffered solution at pH 7.5. Several sharp, well-resolved hyperfine-shifted 1H NMR signals were observed in the 60 to −10 ppm chemical shift range. Comparison of the native and mutant N2OR spectra recorded in H2O-buffered solutions indicated that several additional signals are present in the native protein spectrum. These signals are attributed to a dinuclear copper(II) center. At least …


Online Track Processor For The Cdf Upgrade, C. Ciobanu, J. Gerstenslager, J. Hoftiezer, R. Hughes, M. Johnson, P. Koehn, C. Neu, C. Sanchez, B.L. Winer, J. Freeman, S. Holm, J.D. Lewis, T. Shaw, T. Wesson, Kenneth A. Bloom, D. Gerdes, J.W. Dawson, W.N. Haberichter Aug 1999

Online Track Processor For The Cdf Upgrade, C. Ciobanu, J. Gerstenslager, J. Hoftiezer, R. Hughes, M. Johnson, P. Koehn, C. Neu, C. Sanchez, B.L. Winer, J. Freeman, S. Holm, J.D. Lewis, T. Shaw, T. Wesson, Kenneth A. Bloom, D. Gerdes, J.W. Dawson, W.N. Haberichter

Kenneth Bloom Publications

A trigger track processor is being designed for the CDF upgrade. This processor identifies high momentum (PT > 1.5 GeV/c) charged tracks in the new central outer tracking chamber for CDF 11. The track processor is called the extremely Fast Tracker (XFT). The XFT design is highly parallel to handle the input rate of 183 Gbits/sec and output rate of 44 Gbitslsec. The processor is pipelined and reports the results for a new event every 132 ns. The processor uses three stages, hit classification, segment finding, and segment linking. The pattern recognition algorithms for the three stages are implemented …


Electrodeposition Of Cerium-Based Coatings For Corrosion Protection Of Aluminum Alloys, James O. Stoffer, Thomas J. O'Keefe, Xuan Lin, Eric L. Morris, Pu Yu, Srinivas Pravin Sitaram Aug 1999

Electrodeposition Of Cerium-Based Coatings For Corrosion Protection Of Aluminum Alloys, James O. Stoffer, Thomas J. O'Keefe, Xuan Lin, Eric L. Morris, Pu Yu, Srinivas Pravin Sitaram

Chemistry Faculty Research & Creative Works

A process for enhancing the corrosion resistance of an aluminum-containing component with a cerium based coating. An aluminum-containing cathode and an oxygen- evolving anode are immersed in an electrolyte comprising water, solvent, oxidizing agent and cerium ions. An electrical current is passed through the electrolyte by applying electrical current to deposit a cerium based coating onto the cathode. An electrolyte for use in depositing a cerium based coating. An electrodeposited cerium-based coating. An aluminum aircraft structural component having a cerium-based coating thereon.


Some Notions Of Complex Adaptive Systems And Their Relationship To Our World, Jens G. Pohl Aug 1999

Some Notions Of Complex Adaptive Systems And Their Relationship To Our World, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This paper assumes that the world we live in consists of many interwoven complex adaptive systems. In the literature such systems are characterized as comprising many moving parts and processes that interact significantly in a mostly non-linear manner. It is argued that the forces that act on such complex systems are not additive, and that their impact occurs along non-linear interactions within the system. In particular, many of these systems are adaptive in that they change their behavior (through their interactions) over time, so that if they are subjected to a similar force or event a second time they …


Re-Engineering A Software Development Organization As A Complex Adaptive System, Steven J. Gollery, Jens G. Pohl Aug 1999

Re-Engineering A Software Development Organization As A Complex Adaptive System, Steven J. Gollery, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This paper proposes that it is possible and desirable to restructure a software development organization as a complex adaptive system. Such a structure would increase the possibility that the organization would be able to survive and prosper in a rapidly-changing market place by shortening response time, increasing flexibility in the face of new and unexpected circumstances, and allowing the organization to learn quickly from its experiences.

The paper shows how a common information repository can be used to provide decision support to developers and managers, and discusses the relationship between decision support systems and complex adaptive systems.


The Second Generation Integrated Collaborative Decision Making (Icdm) Model: A Three-Tier Approach To Agent-Based, Decision-Support Systems, Kym J. Pohl, Jens G. Pohl Aug 1999

The Second Generation Integrated Collaborative Decision Making (Icdm) Model: A Three-Tier Approach To Agent-Based, Decision-Support Systems, Kym J. Pohl, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

Ten years ago the CAD Research Center at California Polytechnic University in San Luis Obispo, California identified a standard framework for agent-based, decision support systems. Employing inter-process and inference engine technologies of the time, the CAD Research Center termed this ‘blueprint’ the Integrated Collaborative Decision-Making (ICDM) framework. Over the past twelve years ICDM has been successfully used as a foundation in several systems. These systems focus on a wide range of domains of application including architectural design and ship cargo stowage. Success of the ICDM framework in conjunction with the availability of newer technologies has prompted an evolutionary leap in …


Soil Moisture Within The Windbreak/Crop Interface And A Comparison Of Three Types Of Sensors For Measuring Soil Water Content, Qingjiang Hou Aug 1999

Soil Moisture Within The Windbreak/Crop Interface And A Comparison Of Three Types Of Sensors For Measuring Soil Water Content, Qingjiang Hou

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Central Platte River Forests: Breeding Birds And Woody Vegetation, Barbara K. Good Aug 1999

Central Platte River Forests: Breeding Birds And Woody Vegetation, Barbara K. Good

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


A Drought Watch System For Southeast Spain, Ramon Garrido Abenza Aug 1999

A Drought Watch System For Southeast Spain, Ramon Garrido Abenza

Drought Network News (1994-2001)

One of the main climatological characteristics of the region of Murcia (11,300 km2), located almost entirely in the Segura Basin (in southeast Spain), is the great temporal and spatial irregularity of its precipitation. Average annual precipitation values range between 200 and 500 mm, and coefficients of variation (CV) are high, with some values about 50%. It is a semiarid region (including a small arid area), and agriculture plays a major role in its economy. Because of this, drought is one characteristic of the region’s climate that has far-reaching consequences, from unemployment to social conflicts.

It is important to define drought …


Drought Follows The Deluge In Vermont, Lesley-Ann Dupigny-Giroux Aug 1999

Drought Follows The Deluge In Vermont, Lesley-Ann Dupigny-Giroux

Drought Network News (1994-2001)

The incidence of both drought and flooding on the Vermont landscape within the same calendar year is not an uncommon occurrence. The year 1998 was no exception, in that the ice storm of January and statewide flooding of June/July finally gave way to drought conditions as the year drew to a close. These dry conditions continued into late June/early July 1999, when a series of convective and frontal systems brought steady rainfall amounts that were helpful in reducing the surface moisture deficits. Hydrologic deficits, however, still existed in mid-July.

With the exception of the most severe events, which can span …


Low Temperature And Cold Drought Risks In Crop Production In Temperate Kashmir, Badrul Hasan, Ashok Kumar, A. A. Khan Aug 1999

Low Temperature And Cold Drought Risks In Crop Production In Temperate Kashmir, Badrul Hasan, Ashok Kumar, A. A. Khan

Drought Network News (1994-2001)

Temperature plays a vital role in life processes and crop production. Physical and chemical processes within plants are temperature dependent; these processes in turn control biological reactions in crop plants. Temperature also plays a significant role in some aspects of crop physiological cycles: the diffusion rate of gases and liquids changes with temperature; the solubility of substances is temperature dependent; rapid progress occurs as a result of temperature increases; and the equilibrium and stability of various systems and compounds (including enzymes) is a function of temperature.

Air temperature at the screen level is one of the most important variables affecting …


From The Director: May-August 1999, Donald A. Wilhite Aug 1999

From The Director: May-August 1999, Donald A. Wilhite

Drought Network News (1994-2001)

With increased understanding of El Niño and La Niña events and growing awareness of the wide range of potential impacts, as well as the increased reliability of seasonal climate forecasts for some regions of the world, there is growing interest in the use of climate information to help reduce risk for some weather-sensitive industries, especially agriculture. The National Drought Mitigation Center (NDMC) is currently involved in a project sponsored by the UNDP Office to Combat Desertification and Drought (UNSO) and the World Meteorological Organization, with additional support from NOAA and USAID. The next phase of this project will be a …


Water Current, Volume 31, No. 4, August 1999 Aug 1999

Water Current, Volume 31, No. 4, August 1999

Water Current Newsletter

From Buffalo to Bottled Water, Summer Water Tour Attracts Newcomers
From the Director: Nebraska's Number One Resource? You Be the Judge
1999 Nebraska Water Legislation
Seventh Annual Festival of Color Will be August 28, Near Mead
Two Join Water Sciences Lab Staff
Water News Briefs
Overview of Vision Statements Available
The Value of Water
1999 USBR Hydrologic Modeling Inventory (HMI)
Understanding and Addressing Groundwater Risks
Water Center Faculty Responds to Request from "Down Under"


Induced Changes In Solvent Structure By Phospholipid Monolayer Formation At A Liquid–Liquid Interface, R. A. Walker, D. E. Gragson, G. L. Richmond Aug 1999

Induced Changes In Solvent Structure By Phospholipid Monolayer Formation At A Liquid–Liquid Interface, R. A. Walker, D. E. Gragson, G. L. Richmond

Chemistry and Biochemistry

Vibrational sum frequency spectroscopy has been used in conjunction with dynamic surface tension measurements to study formation of a 1,2-dilauroyl-sn-phosphatidylcholine (DLPC) monolayer at a water–carbon tetrachloride interface. Surface tension measurements show that an aqueous solution of liquid crystalline phosphocholine vesicles (4.5 μM DLPC) requires several hours to form a tightly packed, fully equilibrated monolayer of DLPC monomers. Vibrational spectra of the interfacial region at different stages in the monolayer formation process indicate that the solvent structure undergoes dramatic re-organization as the monolayer forms. Initial adsorption of DLPC monomers severely disrupts the interfacial hydrogen bonding. Intensity in the OH …


Development Of A Hard X-Ray Polarimeter For Astrophysics, Mark L. Mcconnell, John R. Macri, M Mcclish, James M. Ryan, D J. Forrest, W T. Vestrand Aug 1999

Development Of A Hard X-Ray Polarimeter For Astrophysics, Mark L. Mcconnell, John R. Macri, M Mcclish, James M. Ryan, D J. Forrest, W T. Vestrand

Space Science Center

We have been developing a Compton scatter polarimeter for measuring the linear polarization of hard X-rays (100-300 keV) from astrophysical sources. A laboratory prototype polarimeter has been used to successfully demonstrate the reliability of our Monte Carlo simulation code and to demonstrate our ability to generate a polarized photon source in the lab. Our design concept places a self-containedpolarimeter module on the front-end of a a 5-inch position sensitive PMT (PSPMT). We are currently working on the fabrication of a science model based on this PSPMT concept. Although the emphasis of our development effort is towards measuring hard X-rays from …


Announcements: August 1999 Aug 1999

Announcements: August 1999

Drought Network News (1994-2001)

Contents:

Disaster Management Workshops

National Workshop on Dynamic Crop Simulation Modeling

International Conference on Integrated Drought Management

15th Annual Conference on Contaminated Soils

2000 National Disaster Medical System Conference


Enso’S Impact On The Occurrence Of Autumnal Drought In Iran, M. J. Nazemosadat Aug 1999

Enso’S Impact On The Occurrence Of Autumnal Drought In Iran, M. J. Nazemosadat

Drought Network News (1994-2001)

Recent extreme rainfall events and the frequent occurrence of worldwide droughts and their associated natural disasters (i.e., devastating bushfires in Australia, Indonesia, and Italy during 1997; the current severe drought in Iran) have increased the scientific community’s interest in the broad characteristics of rainfall variation and the potential for rainfall prediction.

On the basis of the Koppen climate classification (Ahrens, 1998), the Islamic Republic of Iran (Figure 1) is categorized as generally having arid (BW) and semiarid (BS) climates. This signifies that the annual precipitation is less than the potential annual loss of water through evapotranspiration. The occurrence of rainfall …


Is Hyperconjugation Responsible For The "Gauche Effect" In 1-Fluoropropane And Other 2-Substituted-1-Fluoroethanes?, Paul R. Rablen, R. W. Hoffman, D. A. Hrovat, W. T. Borden Aug 1999

Is Hyperconjugation Responsible For The "Gauche Effect" In 1-Fluoropropane And Other 2-Substituted-1-Fluoroethanes?, Paul R. Rablen, R. W. Hoffman, D. A. Hrovat, W. T. Borden

Chemistry & Biochemistry Faculty Works

The energies and geometries of a series of 2-substituted-1-fluoroethanes were computed at the MP2/6-311++G**(6D)//MP2/6-31+G* level of theory for both the maxima and minima of the rotation about the C-C bond. The results did not support the predictions of a hyperconjugative model, that both 1,2-difluoroethane and 1-chloro-2-fluoroethane would strongly prefer a gauche conformation, and that 1-fluoro-2-silylethane would strongly prefer an anti conformation. The existence of competing electrostatic interactions between the fluorine and the substituents at C-2 was indicated by the detailed geometries of the gauche conformers and by the calculated sensitivity of the gauche-anti energy differences to the presence of a …


Openness And Monotoneity Of Induced Mappings, W. J. Charatonik Aug 1999

Openness And Monotoneity Of Induced Mappings, W. J. Charatonik

Mathematics and Statistics Faculty Research & Creative Works

It is shown that for locally connected continuum X if the induced mapping C(f) : C(X) ->C(Y) is open, then f is monotone. As a corollary it follows that if the continuum X is hereditarily locally connected and C(f) is open, then f is a homeomorphism. An example is given to show that local connectedness is essential in the result.


Summer 1999, Nsu Oceanographic Center Aug 1999

Summer 1999, Nsu Oceanographic Center

Currents

No abstract provided.


Gis And Spatial Statistics: Recent Uk Experiences And Developments., Derek Bond Aug 1999

Gis And Spatial Statistics: Recent Uk Experiences And Developments., Derek Bond

Derek Bond

The uptake and use of GIS in the public sector in the United Kingdom was critically reviewed in a recent paper by Worrall & Bond (1996). Their main conclusion was that the high hopes about the use of GIS that had been prevalent during the late 1980s had failed to materialise. This they argued was due mainly to organisational and implementation issues but also highlighted the lack of effective spatial analysis techniques available to practitioners who have made the heavy investment needed in GIS. In this paper some of the practical developments in spatial analysis that have emerged from the …


16. Eli M. Pearce, Otto Vogl, Judith Pearce Aug 1999

16. Eli M. Pearce, Otto Vogl, Judith Pearce

Otto Vogl

No abstract provided.


Positive Solutions To Semilinear Problems With Coefficient That Changes Sign, Nguyen Phuong Cac, Juan A. Gatica, Yi Li Aug 1999

Positive Solutions To Semilinear Problems With Coefficient That Changes Sign, Nguyen Phuong Cac, Juan A. Gatica, Yi Li

Yi Li

No abstract provided.


Santa Clara Magazine, Volume 41 Number 2, August 1999, Santa Clara University Aug 1999

Santa Clara Magazine, Volume 41 Number 2, August 1999, Santa Clara University

Santa Clara Magazine

8 - APOCALYPSE PAST: Y1K By Thomas Turley. The year 2000 is upon us. But what about Y1K? History Professor Thomas Turley takes an historical look at the millennial fever of a thousand years ago.

12 - THE FUTURE IS MATH By Susan Vogel. Math Lecturer David Sul is on a mission: to get more Hispanics and African-Americans into Calculus and onto college through SCU's Calculus 100 program.

16 - The Class of 1999 Moves On By Sug Ramire '98. Optimism is the byword for the last graduating class of the millennium. Six 1999ers share their impressions, hopes, and fears …


Charge Dynamics In The Half-Metallic Ferromagnet Cro2, E. J. Singley, Christopher P. Weber, D. N. Basov, A. Barry, J. M. D. Coey Aug 1999

Charge Dynamics In The Half-Metallic Ferromagnet Cro2, E. J. Singley, Christopher P. Weber, D. N. Basov, A. Barry, J. M. D. Coey

Physics

Infrared spectroscopy is used to investigate the electronic structure and charge carrier relaxation in crystalline films of CrO2 which is the simplest of all half-metallic ferromagnets. Chromium dioxide is a bad metal at room temperature but it has a remarkably low residual resistivity (<5 >μΩ cm) despite the small spectral weight associated with free carrier absorption. The infrared measurements show that low residual resistivity is due to the collapse of the scattering rate at ω<2000 >cm-1. The blocking of the relaxation channels at low v and T can be attributed to the unique electronic structure of a …


Positive Solutions To Semilinear Problems With Coefficient That Changes Sign, Nguyen Phuong Cac, Juan A. Gatica, Yi Li Aug 1999

Positive Solutions To Semilinear Problems With Coefficient That Changes Sign, Nguyen Phuong Cac, Juan A. Gatica, Yi Li

Mathematics and Statistics Faculty Publications

No abstract provided.