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1998

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Articles 1231 - 1260 of 2574

Full-Text Articles in Physical Sciences and Mathematics

Two-Dimensional Ferroelectric Films, Alexander V. Bune, Vladimir M. Fridkin, Stephen Ducharme, Lev M. Blinov, Serguei P. Palto, Alexander V. Sorokin, S. G. Yudin, A. Zlatkin Feb 1998

Two-Dimensional Ferroelectric Films, Alexander V. Bune, Vladimir M. Fridkin, Stephen Ducharme, Lev M. Blinov, Serguei P. Palto, Alexander V. Sorokin, S. G. Yudin, A. Zlatkin

Stephen Ducharme Publications

Ultrathin crystalline films offer the possibility of exploring phase transitions in the crossover region between two and three dimensions. Second- order ferromagnetic phase transitions have been observed in monolayer magnetic films [1,2], where surface anisotropy energy stabilizes the two-dimensional ferromagnetic state at finite temperature [3]. Similarly, a number of magnetic materials have magnetic surface layers that show a second-order ferromagnetic–paramagnetic phase transition with an increased Curie temperature [4]. Ferroelectricity is in many ways analogous to ferromagnetism, and bulk-like ferroelectricity and finite-size modifications of it have been seen in nanocrystals as small as 250 Å in diameter [5], in perovskite films …


Imaging The Molecular Dimensions And Oligomerization Of Proteins At Liquid/Solid Interfaces, Mark Waner, Martha Gilchrist, Melvin Schindler, Marcos Dantus Feb 1998

Imaging The Molecular Dimensions And Oligomerization Of Proteins At Liquid/Solid Interfaces, Mark Waner, Martha Gilchrist, Melvin Schindler, Marcos Dantus

Mark J. Waner

Individual Concanavalin A (ConA) molecules have been imaged at the liquid/solid interface with an atomic force microscope (AFM). Three-dimensional sizing with very high resolution (<5 Å) has been obtained by a novel approach based on height distributions, which avoids the tip convolution effects which normally affect scanning probe microscopy techniques. Each height measurement correlates to a particular molecular orientation on the surface. A large number of such measurements provide a statistical ensemble of orientations. The complete height distribution reflects the three-dimensional size of the protein sample and hence its tertiary and quaternary structure. A surface adsorption and orientation model, based on a minimization of surface adsorption energy, is proposed. This model is in good agreement with the observed height distribution of Con A molecules at the liquid/solid interface. Analysis of Con A and succinylated Con A molecules on mica demonstrates that Con A dimers are the prevalent species at the liquid/solid interface. This is in contrast to the tetrameric organization of Con A normally observed in solution. The new possibilities opened by height distribution analysis on the physical characterization of biomolecules at interfaces are also discussed.


Air-Snow Exchange Of Hno3 And Noy At Summit, Greenland, Jack E. Dibb, R. Talbot, J W. Munger, Daniel J. Jacob, S M. Fan Feb 1998

Air-Snow Exchange Of Hno3 And Noy At Summit, Greenland, Jack E. Dibb, R. Talbot, J W. Munger, Daniel J. Jacob, S M. Fan

Earth Sciences

Ice core records of NO3 deposition to polar glaciers could provide unrivaled information on past photochemical status and N cycling dynamics of the troposphere, if the ice core records could be inverted to yield concentrations of reactive N oxides in the atmosphere at past times. Limited previous investigations at Summit, Greenland, have suggested that this inversion may be difficult, since the levels of HNO3 and aerosol-associated NO3 over the snow are very low in comparison with those of NO3 in the snow. In addition, it appears that some fraction of the NO3 …


Proper And Unit Bitolerance Orders And Graphs, Kenneth P. Bogart, Garth Isaak Feb 1998

Proper And Unit Bitolerance Orders And Graphs, Kenneth P. Bogart, Garth Isaak

Dartmouth Scholarship

We say any order ≺ is a tolerance order on a set of vertices if we may assign to each vertex x an interval Ix of real numbers and a real number tx called a tolerance in such a way that xy if and only if the overlap of Ix and Iy is less than the minimum of tx and ty and the center of Ix is less than the center of Iy. An order is a bitolerance order if and only if there are intervals Ix and …


The Nomad Experiment At The Cern Sps, Nomad Collaboration, J. Altegoer, M. Anfreville, C. Angelini, P. Astier, M. Authier, D. Autiero, A. Baldisseri, M. Baldo-Ceolin, G. Ballocchi, M. Banner, S. Basa, G. Bassompierre, K. Benslama, I. Bird, B. Blumenfeld, F. Bobisut, J. Bouchez, S. Bunyatov, S. Boyd, Roberto Petti, Et. Al. Feb 1998

The Nomad Experiment At The Cern Sps, Nomad Collaboration, J. Altegoer, M. Anfreville, C. Angelini, P. Astier, M. Authier, D. Autiero, A. Baldisseri, M. Baldo-Ceolin, G. Ballocchi, M. Banner, S. Basa, G. Bassompierre, K. Benslama, I. Bird, B. Blumenfeld, F. Bobisut, J. Bouchez, S. Bunyatov, S. Boyd, Roberto Petti, Et. Al.

Faculty Publications

The NOMAD experiment is a short base-line search for νμντ oscillations in the CERN neutrino beam. The ντ's are searched for through their charged current interactions followed by the observation of the resulting τ− through its electronic, muonic or hadronic decays. These decays are recognized using kinematical criteria necessitating the use of a light target which enables the reconstruction of individual particles produced in the neutrino interactions. This paper describes the various components of the NOMAD detector: the target and muon drift chambers, the electromagnetic and hadronic calorimeters, the preshower and transition radiation …


Redshifted Neutral Hydrogen 21 Centimeter Absorption Toward Red Quasars, C L. Carilli, Karl M. Menten, Mark J. Reid, M P. Rupen, Min S. Yun Feb 1998

Redshifted Neutral Hydrogen 21 Centimeter Absorption Toward Red Quasars, C L. Carilli, Karl M. Menten, Mark J. Reid, M P. Rupen, Min S. Yun

Min S. Yun

We have searched for redshifted neutral hydrogen 21 cm absorption toward sources from the Stickel et al. "red quasar" subsample. The red quasar subsample is taken from the 1 Jy sample of flat-spectrum radio sources and is comprised of the 15 sources that are undetected on the POSS. Five of these red quasars have been searched for redshifted H I 21 cm absorption to optical depth levels of a few percent, and four show strong absorption, with neutral hydrogen column densities between 4 and 80 × 1018 × (Ts/f) cm-2. This 80% success rate for the red quasars compares to …


Lake Whatcom Monitoring Project 1996/1997 Report, Robin A. Matthews, Michael Hilles, Geoffrey B. Matthews Feb 1998

Lake Whatcom Monitoring Project 1996/1997 Report, Robin A. Matthews, Michael Hilles, Geoffrey B. Matthews

Lake Whatcom Annual Reports

This report is part of an on-going series of annual reports and special project reports that document the Lake Whatcom monitoring program.

This work is conducted by the Institute for Watershed Studies and other departments at Western Washington University. The major objective of this program is to provide long-term baseline water quality monitoring in Lake Whatcom and selected tributaries. Each section contains brief explanations about the water quality data, along with discussions of patterns observed in Lake Whatcom.


Changes In Metallicity And Electronic Structure Across The Surface Ferroelectric Transition Of Ultrathin Crystalline Poly(Vinylidene Fluoride-Trifluoroethylene) Copolymers, Jaewu Choi, Peter A. Dowben, Shawn Pebley, A.V. Bune, Stephen Ducharme, V.M. Fridkin, S.P. Palto, N. Petukhova Feb 1998

Changes In Metallicity And Electronic Structure Across The Surface Ferroelectric Transition Of Ultrathin Crystalline Poly(Vinylidene Fluoride-Trifluoroethylene) Copolymers, Jaewu Choi, Peter A. Dowben, Shawn Pebley, A.V. Bune, Stephen Ducharme, V.M. Fridkin, S.P. Palto, N. Petukhova

Peter Dowben Publications

The surface ferroelectric-paraelectric phase transition in crystalline copolymer films of vinylidene fluoride (70%) with trifluoroethylene (30%), at about 20 °C, is accompanied by a dramatic change in both the electronic structure and metallicity. The temperature-dependent changes in the electronic structure occur primarily in the conduction band. This P(VDF-TrFE 70:30) material is observed to resemble an n-type semiconductor, and the change in electronic structure at the surface ferroelectric transition resembles a semiconductor-to-semimetal transition.


(Wa: 085755475693) Jual Obat Aborsi Di Garut, Aborsi Cytotec, Aborsi Cytotec Feb 1998

(Wa: 085755475693) Jual Obat Aborsi Di Garut, Aborsi Cytotec, Aborsi Cytotec

aborsi cytotec

PERCAYAKAN pada saya maka anda tidak akan menyesal. jangan pernah coba coba dalam hal obat yg di minum karena obat yg sudah masuk ke dalam tubuh bekerja langsung ke dalam organ dan syaraf tubuh jadi pilihlah obat yg pasti, ambil obat yg berkualitas tinggi dan tentunya harga juga sedikit tinggi karna memang teruji keaslianya dan kualitas nya


The Set Of Hemispheres Containing A Closed Curve On The Sphere, Mary Kate Boggiano, Mark Desantis Feb 1998

The Set Of Hemispheres Containing A Closed Curve On The Sphere, Mary Kate Boggiano, Mark Desantis

Department of Math & Statistics Technical Report Series

Suppose you get in your car and take a drive on the sphere of radius R, so that when you return to your starting point the odometer indicates you've traveled less than 2πR. Does your path, γ, have to lie in some hemisphere?

This question was presented to us by Dr. Robert Foote of Wabash College. Previous authors chose two points, A and B, on γ such that these points divided γ into two arcs of equal length. Then they took the midpoint of the great circle arc joining A and B to be the North Pole and showed that …


Light Curve Changes In The Eclipsing Binary V719 Her, Edward G. Schmidt Feb 1998

Light Curve Changes In The Eclipsing Binary V719 Her, Edward G. Schmidt

Department of Physics and Astronomy: Faculty Publications

The General Catalogue of Variable Stars (Kholopov 1985) lists V719 Her as a probable type c RR Lyrae star with a period of 0.336 days. In the remarks, it is noted that another possibility is that V719 Her is a W UMa eclipsing binary with a period of .67 days. Schmidt (1991; 1993) obtained 15 light curve points in 1989-91 and concluded that V719 Her is indeed a W UMa star but with a period of .400995 days. Goderya, Leung and Schmidt (1996; 1997) subsequently obtained extensive photometry in 1993 which pro¬vided timings for five minima over an interval of …


Semi-Permanent Vacuum Closure With Multiple Retubulation Capability, Arthur A. Eneim, Tom K. Evans, Timothy S. Romano, Gary B. Hughes Feb 1998

Semi-Permanent Vacuum Closure With Multiple Retubulation Capability, Arthur A. Eneim, Tom K. Evans, Timothy S. Romano, Gary B. Hughes

Statistics

A vacuum system (20) includes an enclosure (22) having a vacuum-tight wall (26) and an internally threaded aperture (66) through the wall (26). A tip-off fitting (24) has a base (50) with a bore (52) therethrough, a hollow tube (62) fixed to the base (50) with a vacuum-tight seal, such that an interior (64) of the tube (62) is in communication with the bore (52) in the base (50), and an external thread (58) on the exterior of the base (50). The external thread (58) on the exterior of the base (50) is dimensioned to threadably engage the internal thread …


Recognizing Constant Curvature Discrete Groups In Dimension 3, J. W. Cannon, E. L. Swenson Feb 1998

Recognizing Constant Curvature Discrete Groups In Dimension 3, J. W. Cannon, E. L. Swenson

Faculty Publications

We characterize those discrete groups Gwhich can act properly discontinuously, isometrically, and cocompactly on hyperbolic 3-space H^3 in terms of the combinatorics of the action of G on its space at infinity. The major ingredients in the proof are the properties of groups that are negatively curved (in the large) (that is, Gromov hyperbolic), the combinatorial Riemann mapping theorem, and the Sullivan-Tukia theorem on groups which act uniformly quasiconformally on the 2-sphere.


Announcements: February 1998 Feb 1998

Announcements: February 1998

Drought Network News (1994-2001)

Contents:

Hazards and Sustainability: Contemporary Issues in Risk Management

Hazards–98: Seventh International Symposium on Natural and Man-made Hazards

Water: A Looming Crisis? International Conference on World Water Resources at the Beginning of the 21st Century

Disaster Forum ’98

National Conference on Lifesaving Intervention

New Book: Reaching the Unreached: Challenges for the 21st Century


Spring Crops In Bulgaria Damaged By 1996 Summer Drought, Nikola Slavov, Vesselin Alexandrov Feb 1998

Spring Crops In Bulgaria Damaged By 1996 Summer Drought, Nikola Slavov, Vesselin Alexandrov

Drought Network News (1994-2001)

Studies suggest there is a decreasing trend in precipitation in both north and south Bulgaria because of precipitation deficiencies in the 1940s and since the 1970s. Bulgaria has experienced several summer drought episodes during the last century, most notably in the 1940s and 1980s. There has been a decreasing trend in precipitation during the potential crop-growing season since the end of the 1970s, and the number of 10-day dry spells during this season has increased since the beginning of the 1970s. In the course of the last 3 decades, there was a decreasing trend in precipitation during the non-growing season …


Droughts In Poland, 1951-90, R. Farat, M. Kepinska - Kasprzak, P. Kowalczak, P. Mager Feb 1998

Droughts In Poland, 1951-90, R. Farat, M. Kepinska - Kasprzak, P. Kowalczak, P. Mager

Drought Network News (1994-2001)

One of the negative features of Poland’s climate is the periodic occurrence of atmospheric droughts. The most frequent source of this phenomenon is the occurrence of long-term (sometimes lasting several weeks) rainless periods. The occurrence of these periods is connected with the persistence of a stationary east European high that joins with the Azores anticyclone via central Europe. In such situations, with the accompanying lack or insufficiency of atmospheric precipitation, a drought begins to develop gradually. First, a soil drought appears, followed by hydrologic drought. During a hydrologic drought, a decrease in the ground water flow into surface waters is …


India, Indonesia Experiencing Opposite Effects From 1997 El Niño, R. H. Kripalani, Ashwini Kulkarni Feb 1998

India, Indonesia Experiencing Opposite Effects From 1997 El Niño, R. H. Kripalani, Ashwini Kulkarni

Drought Network News (1994-2001)

It is now well recognized that the El Niño/Southern Oscillation (ENSO) phenomenon is the single most important cause of year-to-year climatic variability. Several studies have documented that a majority of the warm extremes (El Niño events) cause below-normal rainfall over Indonesia, while cold extremes (La Niña events) cause above-normal rainfall over India.

During the current ongoing El Niño episode, temperature anomalies in the Niño 1+2, Niño 3, and Niño 3.4 regions have been the largest values observed in the last 50 years. The pattern of anomalous tropical convection with enhanced activity across the central and eastern equatorial Pacific and suppressed …


Planning For The Next Drought: A National Drought Mitigation Center Workshop Sponsored By The U.S. Bureau Of Reclamation And The National Governors’ Association Feb 1998

Planning For The Next Drought: A National Drought Mitigation Center Workshop Sponsored By The U.S. Bureau Of Reclamation And The National Governors’ Association

Drought Network News (1994-2001)

The drought that gripped the Southwest and southern Great Plains states in 1996 was the most recent reminder of the nation’s continuing and apparently increasing vulnerability to drought. Although drought is a common feature in the West, it is a normal part of the climate of each region of the United States: drought struck the Southeast in 1986; most of the country, especially the Midwest and Plains states, in 1988–89; the West from 1987 to 1992; and the Northeast in 1995. Experiences from each of these droughts reinforce the need for advance planning. Even though drought is a slow-onset disaster, …


Quarterly Report Provides Assessment Of Western Water Supply Indicators Feb 1998

Quarterly Report Provides Assessment Of Western Water Supply Indicators

Drought Network News (1994-2001)

A new quarterly report, Western Climate and Water Status, provides decision makers in the western United States with a comprehensive assessment of water supply indicators that can give early warning of emerging droughts. A product of the Western Drought Coordination Council, the report is an important new connection between scientists and policy makers.


Water Center, Volume 30, No. 1, February 1998 Feb 1998

Water Center, Volume 30, No. 1, February 1998

Water Current Newsletter

Resource Institute Working to Restore Native Prairies and Wetlands
From the Director: Water Conference, Seminar Series, USGS Grants
The Clean Water Act: A Twenty-Five Year Retrospective
CWA Has Positive Effects, But Future Cloudy
Still Time to Register for "Nebraska Water 2000"
Study Shows Risk of Animal Waste
Investigators Focus Attention on Community Drinking Water Disinfection
Water News Briefs
GW Foundation's Festival Expedition
Nominations for Haverstick Award
EPA Publications on Line
Source Water Assessment Program
E-Answers
Groundwater University and Groundwater Grad School


Constructions Of Random Distributions Via Sequential Barycenters, Theodore P. Hill, Michael Monticino Feb 1998

Constructions Of Random Distributions Via Sequential Barycenters, Theodore P. Hill, Michael Monticino

Research Scholars in Residence

This article introduces and develops a constructive method for generating random probability measures with a prescribed mean or distribution of the means. The method involves sequentially generating an array of barycenters which uniquely defines a probability measure. Basic properties of the generated measures are presented, including conditions under which almost all the generated measures are continuous or almost all are purely discrete or almost all have finite support. Applications are given to models for average-optimal control problems and to experimental approximation of universal constants.


China’S Drought Climate Monitoring System, Zhu Changhan, Zhang Qiang, Wu Hong Feb 1998

China’S Drought Climate Monitoring System, Zhu Changhan, Zhang Qiang, Wu Hong

Drought Network News (1994-2001)

In China, about 50% of the country is in arid and semiarid regions. Drought is the most severe climate disaster to affect China, and it causes significant reductions in grain yields. The area affected annually by drought has been estimated at about 20 million ha, which accounts for 59% of the total area affected by disasters. When severe droughts occur, they can affect as much as 33 million ha.

To monitor the occurrence and development of droughts efficiently and provide information on the strength and range of droughts and floods, the China Drought–Flood Climate Monitoring System was developed by the …


Positive Knots And Robinson's Attractor, Michael C. Sullivan Feb 1998

Positive Knots And Robinson's Attractor, Michael C. Sullivan

Articles and Preprints

We study knotted periodic orbits which are realized in an attractor of a certain ODE. These knots can be presented so as to have all positive crossings, but may not be restricted to positive braids.


Hyalotekite, (Ba,Pb,K)(4)(Ca,Y)(2)Si-8(B,Be)(2)(Si,B)(2)O28f, A Tectosilicate Related To Scapolite: New Structure Refinement, Phase Transitions And A Short-Range Ordered 3b Superstructure, A. G. Christy, Edward S. Grew, S. C. Mayo, Martin G. Yates, Dimitriy I. Belakovskiy Feb 1998

Hyalotekite, (Ba,Pb,K)(4)(Ca,Y)(2)Si-8(B,Be)(2)(Si,B)(2)O28f, A Tectosilicate Related To Scapolite: New Structure Refinement, Phase Transitions And A Short-Range Ordered 3b Superstructure, A. G. Christy, Edward S. Grew, S. C. Mayo, Martin G. Yates, Dimitriy I. Belakovskiy

Earth Science Faculty Scholarship

Hyalotekite, a framework silicate of composition (Ba,Pb,K)(4)(Ca,Y)(2)Si-8(B,Be)(2) (Si,B)(2)O28F, is found in relatively high-temperature(greater than or equal to 500 degrees C) Mn skarns at Langban, Sweden, and peralkaline pegmatites at Dara-i-Pioz, Tajikistan. A new paragenesis at Dara-i-Pioz is pegmatite consisting of the Ba borosilicates leucosphenite and tienshanite, as well as caesium kupletskite, aegirine, pyrochlore, microcline and quartz. Hyalotekite has been partially replaced by barylite and danburite. This hyalotekite contains 1.29-1.78 wt.% Y2O3, equivalent to 0.172-0.238 Y pfu or 8-11% Y on the Ca site; its Pb/(Pb+Ba) ratio ranges 0.36-0.44. Electron microprobe F contents of Langban and Dara-i-Pioz hyalotekite range 1.04-1.45 wt.%, …


Environmental Variability Effects On Marine Fisheries: Four Case Histories, Eileen E. Hofmann, T. M. Powell Feb 1998

Environmental Variability Effects On Marine Fisheries: Four Case Histories, Eileen E. Hofmann, T. M. Powell

CCPO Publications

The changing nature of marine fisheries requires management approaches that recognize and include ecosystem and environmental effects. Therefore, we review some examples of exploited fishery stocks in which environmental control is a major contributor to structuring the abundance and distribution of the stock. Four examples, taken from studies of northern cod (Gadus morhua), cod and haddock (Melanogrammus aeglefinus) larvae, the eastern oyster (Crassostrea virginica), and Antarctic krill (Euphausia superba), are given that clearly illustrate environmental control on the fishery. From these examples, we argue that future management strategies for exploited fisheries must include effects of environmental variability. In particular, management …


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 14, Number 2, February 1998, College Of Engineering And Computer Science, Wright State University Feb 1998

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 14, Number 2, February 1998, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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


Focus Areas Along The Taunton River: Natural Resources Inventory And Conservation Plan, Wildlands Trust Of Southeastern Massachusetts Feb 1998

Focus Areas Along The Taunton River: Natural Resources Inventory And Conservation Plan, Wildlands Trust Of Southeastern Massachusetts

Reference Documents

No abstract provided.


Distribution Of Heavy Metal And Pcb Contaminants In The Sediments Of An Urban Estuary: The Hudson River, Huan Feng, J. Kirk Cochran, Honoratha Lwiza, Bruce J. Brownawell, David J. Hirschberg Feb 1998

Distribution Of Heavy Metal And Pcb Contaminants In The Sediments Of An Urban Estuary: The Hudson River, Huan Feng, J. Kirk Cochran, Honoratha Lwiza, Bruce J. Brownawell, David J. Hirschberg

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Surficial sediments obtained from sediment cores were collected over 100 km along the axis of the lower Hudson River in June 1994, November 1994, May 1995 and April 1996 and showed the presence of anthropogenic Ag, Cd, Cu, Pb, Zn, PCBs in all samples. Contaminant distributions in the Hudson River estuary show two types of trends: Ag, Cu and Pb show an increasing trend down-estuary with maximum values in New York Harbor sediments; in contrast, Cd, Zn and total PCBs display a decreasing trend toward New York Harbor where urban sources are also apparent. Silver is a useful tracer of …


The Probe, Issue 185 – February 1998 Feb 1998

The Probe, Issue 185 – February 1998

The Probe: Newsletter of the National Animal Damage Control Association

Animal Rights Groups Should Give Shelters Money, by Susan E. Paris
In Memoriam--Obituary: Norton R. Miner
From the President -- Robert H. Giles, Jr., President, NADCA
Job Announcements: 1. Coordinator, Isabela Project, Galapagos National Park Service; 2. Leader of Eradication Program Galapagos National Park Service
Brochure Provides Advice to Ranchers on Wolf Livestock Kills
Seattle Coyote Gets A Lift
Radio Says "No Thanks" to Fund
Oregon Mink Farms Attacked
Rabies Down, Tapeworms Up in European Foxes

More Reports From the 4th Annual Conference of The Wildlife Society:
Linking Spatial Heterogeneity and Social Behavior to Carnivore Population Dynamics: Development and Evaluation …


Piece Cementowe - Konkurencja Dla Spalarni Odpadów, Robert Oleniacz Feb 1998

Piece Cementowe - Konkurencja Dla Spalarni Odpadów, Robert Oleniacz

Robert Oleniacz

The paper presents the advantages of cement kilns and the possibility of their use for thermal waste utilization. The most common types of waste incinerated in these kilns and the possible degree of replacing traditional fuels with waste fuels have also been characterized. The work also discusses the problem of air pollutant emissions from the process of waste co-incineration in cement kilns. Attention has been paid to the possible increase in the use of Polish cement industry in the waste management, system, especially in the field of energy recovery from solid municipal waste, waste tires and waste from the refinery …