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1998

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Articles 2071 - 2100 of 2339

Full-Text Articles in Physical Sciences and Mathematics

Commingling Of Contrasted Magmas In Various Geodynamic Settings, Bernard Plateovet, Jean Bebien, Edilene Gomes Jan 1998

Commingling Of Contrasted Magmas In Various Geodynamic Settings, Bernard Plateovet, Jean Bebien, Edilene Gomes

Turkish Journal of Earth Sciences

Three acid-basic associations taken in various geodynamical settings are studied: the gabbro-granite association of Porto (Corsica), the associations of the Guevgueli (Greek Macedonia), and the associations of the Piracaia complex (Brazil). The diversity of field relations, the degree of mingling, the origins of the melts are debated for each association, using petrological and geochemical tools for each acid-basic association. An origin by hybridization is assumed for the intermediate rocks of the Porto association, it is tested by numerical calculation. Then, we focus on the mixing process between the comagmatic components. Mixing of melts may have happened by thorough mingling and …

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Post-Collisional Central Anatolian Alkaline Plutonism, Turkey, Durmuş Boztuğ Jan 1998

Post-Collisional Central Anatolian Alkaline Plutonism, Turkey, Durmuş Boztuğ

Turkish Journal of Earth Sciences

A number of Upper Cretaceous-Palaeogene alkaline plutons intruded into the crustal metamorphic rocks, the pre-Maastrichtian ophiolitic mélange, and the Cretaceous-Lower Tertiary units are located in the Central Anatolia (CA), Turkey. These alkaline plutons constitute an important association in the post-collisional Central Anatolian Granitoids. The Dumluca, Murmana, Karakeban, Kösedağ, Hasançelebi, Karaçayir and Davulalan plutons constitute the eastern; whereas the Egrialan, Baranadağ, Hamit, Çamsarı, Durmuslu and Bayindir units the western part of this alkaline association. These plutons are mainly composed of silica oversaturated syenitic to monzonitic, and undersaturated syenitic felsic rocks. However, the Dumluca, Murmana and Karakeban plutons also include some undersaturated …

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Tectono-Magmatic Evolution Of Alkaline Volcanics At Thekırka-Afyon-Isparta Structural Trend, Sw Turkey, M. Yilmaz Savaşcin, Tolga Oyman Jan 1998

Tectono-Magmatic Evolution Of Alkaline Volcanics At Thekırka-Afyon-Isparta Structural Trend, Sw Turkey, M. Yilmaz Savaşcin, Tolga Oyman

Turkish Journal of Earth Sciences

The youngest Alpine magmatism (Miocene to Quaternary) in Western and Central Anatolia is represented by three coeval assemblages from West to East. They are the Western Anatolian Volcanic assemblage (WAV), the N-S trending Kirka-Afyon-Isparta Alkaline Volcanic assemblage (KAIAV) and the Central Anatolian Volcanic Provinces (CAVP). The WAV and CAVP start with calc-alka-line volcanics and continue after Middle Miocene with shoshonitic to alkaline products of graben volcanism, while the KAIAV are all alkaline in character, without any former or later calc-alkaline contributions. The KAIAV are emplaced in three steps of alkaline vol-canic activities which exhibit southward younging along the N-S Kirka-Afyon-Isparta …

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The Coexistence Of The Silica Oversaturated (Alkos) And Undersaturated Alkaline (Alkus) Rocks In The Kortundag And Baranadag Plutons From The Central Anatolian Alkaline Plutonism, E Kaman/Nw Kırşehir, Turkey, Nazmi̇ Otlu, Durmuş Boztuğ Jan 1998

The Coexistence Of The Silica Oversaturated (Alkos) And Undersaturated Alkaline (Alkus) Rocks In The Kortundag And Baranadag Plutons From The Central Anatolian Alkaline Plutonism, E Kaman/Nw Kırşehir, Turkey, Nazmi̇ Otlu, Durmuş Boztuğ

Turkish Journal of Earth Sciences

Baranadağ and Kortundağ plutons, outcropping in the Kaman-Kırşehir region, constitute the important members of the Central Anatolian post-collisional alkaline plutonism. The Baranadağ pluton comprises only one lithodem called Baranadağ quartz monzonite, whereas, the Kortundağ pluton consists of four mapable units such as Hamit quartz syenite, Durmuslu nepheline-nosean-melanite porphyritic syenite, Bayındır nepheline-cancrinite syenite, and Çamsarı quartz syenite. Among these units, the Baranadağ quartz monzonite and Hamit quartz syenite cut the metamorphics of the Kırşehir Block. On the other hand, Durmuslu, Bayindir and Çamsarı are emplaced in both the Hamit quartz syenite and the metamorphics. The Baranadağ quartz monzonite, Hamit quartz syenite …

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Lave Caves Of Kilimanjaro. Mawenzi Lava Tubes, Clive Ward Jan 1998

Lave Caves Of Kilimanjaro. Mawenzi Lava Tubes, Clive Ward

International Journal of Speleology

This is the first short report on the exploration of lava tubes in the upper part of Kilimanjaro. The area seems to be extremely interesting from vulcanospeleological point of view.

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Lava Caves Of Grande Comore, Indian Ocean: An Initial Reconnaissance, September 1997, Gregory J. Middleton Jan 1998

Lava Caves Of Grande Comore, Indian Ocean: An Initial Reconnaissance, September 1997, Gregory J. Middleton

International Journal of Speleology

What are believed to have been the first speleological investigations in the Comoros Islands were carried out on Grande Comore island between 7 and 13 September 1997. A number of caves were located with the help of local informants and the more significant ones surveyed. Exploration of some caves was not able to be completed. The potential for further significant discoveries is believed to be high.

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"Pit Craters", Lava Tubes, And Open Vertical Volcanic Conduits In Hawaii: A Problem In Terminology, William R. Halliday Jan 1998

"Pit Craters", Lava Tubes, And Open Vertical Volcanic Conduits In Hawaii: A Problem In Terminology, William R. Halliday

International Journal of Speleology

Almost from the 1849 publication of the term pit crater, volcanologists have disagreed about the parameters differentiating these features from other vertical volcanic structures. Kaluaiki is a jameo giving entry to Thurston Lava Tube in Hawaii Volcanoes National Park. Long-standing misidentification of it as a pit crater is an example of misunderstandings arising from the lack of a clear definition of pit crater. In general, pit craters are unrelated to lava tube caves genetically, but two special cases are discussed. One probably is genetically related to a rift tube deep below the surface; the other is a complex of a …

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Lava Tube Remelt By Radiant Heat And Burning Gasses, Kevin Allred Jan 1998

Lava Tube Remelt By Radiant Heat And Burning Gasses, Kevin Allred

International Journal of Speleology

Some volcanologists assume that interior surfaces of hot lava tubes can commonly be remelted by burning gases and radiant heat. Pending further data, this appears to be unlikely.

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The Origin Of Tubular Lava Stalactites And Other Related Forms, Kevin Allred, Carlene Allred Jan 1998

The Origin Of Tubular Lava Stalactites And Other Related Forms, Kevin Allred, Carlene Allred

International Journal of Speleology

Tubular lava stalactites are often found in lava tubes. Field observations, sample analysis, and comparative studies indicate that these are segregations extruded during cooling from partially crystallized lava al about 1,070 - 1,000 °C. Retrograde boiling (gas pressure) within the lava provides a mechanism to expel the interstitial liquid. In addition to tubular lava stalactites, a variety of other lava features can also result, such as lava helictites, lava coralloids, barnacle-like stretched lava, runners, runner channels, and some lava blisters and squeeze-ups.

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The 1981 Eruptive Fissure On Mt. Etna: Considerations On Its Exploration And Genesis, Angelo Leotta, Marco Liuzzo Jan 1998

The 1981 Eruptive Fissure On Mt. Etna: Considerations On Its Exploration And Genesis, Angelo Leotta, Marco Liuzzo

International Journal of Speleology

This paper is targeted to an analysis of features common to various fissure caves on Mt. Etna, Sicily. The Authors report the preliminary results of the exploration carried out in the 1981 eruptive fissure, the technical problems met during the exploration, the flow trends and the different courses of the molten material inside the fissure, the particular morphologies. A genetic model is proposed, different from those characterising the lava tube cave genesis, and links are suggested between the various fissures and the main tectonic stress systems operating on Mt. Etna, as well as the morpho-structural conditions of the volcanic edifice …

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Success With Serradella In The Wheatbelt, Clinton Revell, Bradley Nutt, Michael Ewing Jan 1998

Success With Serradella In The Wheatbelt, Clinton Revell, Bradley Nutt, Michael Ewing

Journal of the Department of Agriculture, Western Australia, Series 4

Clinton Revell, Bradley Nutt, and Michael Ewing review the latest developments with new varieties of French serradella and yellow seradella that should provide the basis for productive legume pastures on acidic, sandy soils throughout the wheatbelt of Western Australia

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Journal Of Mathematics And Science: Collaborative Explorations Jan 1998

Journal Of Mathematics And Science: Collaborative Explorations

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

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The Integral Role Of Borough Of Manhattan Community College In The Mathematics Preparation Of Prospective Teachers, J. Gaston Jan 1998

The Integral Role Of Borough Of Manhattan Community College In The Mathematics Preparation Of Prospective Teachers, J. Gaston

Journal of Mathematics and Science: Collaborative Explorations

Borough of Manhattan Community College (BMCC) of the City University of New York (CUNY) is the only two-year college on the island of Manhattan. This institution has a diverse population of approximately 17,000 students who attend day/evening/weekend classes. Over 1,000 students are enrolled in the Early Childhood Education (ECE) Program. Each year, approximately 300 new students select this area of concentration. The dropout rate is less than 14%. The ECE Program prepares students for elementary education programs at four-year institutions. The program also offers two career areas of study: Infant Toddler and Pre-School. This article will discuss how high quality …

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The Integral Role Of Tulsa Community College In The Mathematics And Science Preparation Of Prospective Teachers, C. Thompson Jan 1998

The Integral Role Of Tulsa Community College In The Mathematics And Science Preparation Of Prospective Teachers, C. Thompson

Journal of Mathematics and Science: Collaborative Explorations

The role of the two-year college in the mathematics and science preparation of prospective teachers is fast becoming a prominent influence on teacher education programs across the country. This article describes the multifaceted role of Tulsa Community College (TCC), Tulsa, Oklahoma, in the preparation of prospective teachers in math and science. Since 1987 Tulsa Community College has hosted many events, activities, and programs aimed at the sciences. TCC activities/programs have focused on five areas: (1) preservice and inservice preparation; (2) summer teacher institutes supported by state and federal grants; (3) recruitment and emphasis on underrepresented groups; (4) parateacher associate degree/certification …

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Preservice Teacher Education: Alive And Well At Two-Year Colleges, R. Collins, V. Bergeron Jan 1998

Preservice Teacher Education: Alive And Well At Two-Year Colleges, R. Collins, V. Bergeron

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

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College Of San Mateo Mathematics And Science Teacher Education Program: A Bay Area Collaborative For Excellence In Teacher Preparation With San Jose State University And San Francisco State University, C. Tonini Jan 1998

College Of San Mateo Mathematics And Science Teacher Education Program: A Bay Area Collaborative For Excellence In Teacher Preparation With San Jose State University And San Francisco State University, C. Tonini

Journal of Mathematics and Science: Collaborative Explorations

The College of San Mateo (CSM), a community college serving the San Mateo County area of California, is part of a collaborative effort in the San Francisco Bay Area to improve mathematics and science teacher preparation. With funding mainly through the National Science Foundation, the project is locally referred to as the MASTEP Project (Math and Science Teacher Education Program). MASTEP partners include two California State Universities (San Jose State University and San Francisco State University), four community colleges (College of San Mateo, City College of San Francisco, Evergreen Valley Community College, and San Jose City College), selected K-12 schools, …

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The Community College Of Philadelphia: Educating Teachers For A Changing World, K. Armstrong Jan 1998

The Community College Of Philadelphia: Educating Teachers For A Changing World, K. Armstrong

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

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Collaborative Efforts To Enhance And Strengthen Teacher Training In Mathematics And Science, G. Turbeville, D. Jovanovich Jan 1998

Collaborative Efforts To Enhance And Strengthen Teacher Training In Mathematics And Science, G. Turbeville, D. Jovanovich

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

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Aims & Scope Jan 1998

Aims & Scope

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

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The Submilimeter-Wave Rotational Spectrum Of Isopropyl Alcohol, C. Qajar, S. Musaev Jan 1998

The Submilimeter-Wave Rotational Spectrum Of Isopropyl Alcohol, C. Qajar, S. Musaev

Turkish Journal of Physics

The submilimeter-wave spectrum of the {\em trans} isopropyl alcohol was studied in the frequency range from 240 to 480 GHz. More than 170 lines were assigned to ground state transition. The identification of the high $J$ transitions was checked by centrifugal distortion analysis. The frequencies of all transitions were least squares fitted to the Watson's Hamiltonian, including two $P^8$ terms. The ground-state rotational constants are (in MHz) A = 8489.0150, B = 8041.9182, C = 4765.2326, which yield an asymmetry parameter $\kappa = 0.75986663$.

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Quaternionic Roots Of E 8 Related Coxeter Graphs And Quasicrystals, Mehmet Koca, Nazife Özdeş Koca, Ramazan Koç Jan 1998

Quaternionic Roots Of E 8 Related Coxeter Graphs And Quasicrystals, Mehmet Koca, Nazife Özdeş Koca, Ramazan Koç

Turkish Journal of Physics

The lattice matching of two sets of quaternionic roots of $F_4$ leads to quaternionic roots of $E_8$ which has a decomposition $H_4 + \sigma H_4$ where the Coxeter graph $H_4$ is represented by the 120 quaternionic elements of the binary icosahedral group. The 30 pure imaginary quaternions constitute the roots of $H_3$ which has a natural extension to $H_3 + \sigma H_3$ describing the root system of the Lie algebra $D_6$. It is noted that there exist three lattices in 6-dimensions whose point group $W(D_6)$ admits the icosahedral symmetry $H_3$ as a subgroup, the roots of which describe the mid-points …

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The Structure Of (001) Csl Twist Boundaries In Fcc Metals, A. Ghafoor, S.A. Ahmad, B.A.S. Faridi Jan 1998

The Structure Of (001) Csl Twist Boundaries In Fcc Metals, A. Ghafoor, S.A. Ahmad, B.A.S. Faridi

Turkish Journal of Physics

Computer simulation techniques based on discrete lattice approach and empirical many-body potentials have been used to study the structure and energy of $\Sigma = 5$, and $\Sigma = 13$ coincident site lattice (001) twist boundaries in three fcc metals. Energy computed for $\Sigma = 5$ boundary in copper is 17.5 \% less than the earlier result obtained by using pair potential. However the present calculations of twist boundary energies are somewhat higher than the results obtained using embedded atom method.

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The Energy Spectra Of Gaas/Al_Xga_{1-X}As Quantum Dots, Mohammad El-Said, M. Abu Saa Jan 1998

The Energy Spectra Of Gaas/Al_Xga_{1-X}As Quantum Dots, Mohammad El-Said, M. Abu Saa

Turkish Journal of Physics

The energy expressions for QD presented in high- and low-magnetic fields are calculated. An interpolation formula between the energies of the quantum dot in both limits is proposed. The formula is implemented to produce the energy spectra of the parabolic quantum dot in the presence of a magnetic field of arbitrary strength. The transitions in the angular momenta of the ground state energy of interacting electrons confined in the quantum dot as a function of magnetic field strength is studied. A good agreement is obtained when our results are tested against exact numerical work.

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Madison County Test Hole Logs, Raymond R. Burchett Jan 1998

Madison County Test Hole Logs, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Earthquakes In Nebraska, R. R. Burchett Jan 1998

Earthquakes In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Oil And Gas Fields In Nebraska, R. R. Burchett Jan 1998

Oil And Gas Fields In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Lee Weights Of Z/4z-Codes From Elliptic Curves, José Felipe Voloch, Judy L. Walker Jan 1998

Lee Weights Of Z/4z-Codes From Elliptic Curves, José Felipe Voloch, Judy L. Walker

Department of Mathematics: Faculty Publications

In [15: J. L. Walker, Algebraic geometric codes over rings], the second author defined algebraic geometric codes over rings. This definition was motivated by two recent trends in coding theory: the study of algebraic geometric codes over finite fields, and the study of codes over rings. In that paper, many of the basic parameters of these new codes were computed. However, the Lee weight, which is very important for codes over the ring Z/4Z, was not considered. In [14: J.-F. Voloch and J. L. Walker, Euclidean weights of codes from elliptic curves over rings], this …

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Estimates Of Annual Survival Probabilities For Adult Florida Manatees (Trichechus Manatus Latirostris), C. A. Langtimm, T. J. O'Shea, R. Pradel, C. A. Beck Jan 1998

Estimates Of Annual Survival Probabilities For Adult Florida Manatees (Trichechus Manatus Latirostris), C. A. Langtimm, T. J. O'Shea, R. Pradel, C. A. Beck

United States Geological Survey: Staff Publications

The population dynamics of large, long-lived mammals are particularly sensitive to changes in adult survival. Understanding factors affecting survival patterns is therefore critical for developing and testing theories of population dynamics and for developing management strategies aimed at preventing declines or extinction in such taxa. Few studies have used modern analytical approaches for analyzing variation and testing hypotheses about survival probabilities in large mammals. This paper reports a detailed analysis of annual adult survival in the Florida manatee (Trichechus manatus latirostris), an endangered marine mammal, based on a mark-recapture approach. Natural and boat- inflicted scars distinctively "marked" individual …

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Book Review Of Paleolimnology Of Europeanmaar Lakes By J. F.W. Negendank & B. Zolitschka (Eds)., J. Platt Bradbury Jan 1998

Book Review Of Paleolimnology Of Europeanmaar Lakes By J. F.W. Negendank & B. Zolitschka (Eds)., J. Platt Bradbury

United States Geological Survey: Staff Publications

This book represents a collection of papers presented at a symposium in May, 1991 on the formation and paleolimnology of European maar lakes. Paleolimnological discussions embrace maar lake deposits of late Quaternary to early Tertiary age in Germany, France and Italy. The goal of the symposium and its outgrowth, this book, is to develop a funding initiative to study, core and analyze the deposits of these remarkable depositional systems.

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Observation Of The Seismic Nucleation Phase In The Ridgecrest, California, Earthquake Sequence, William L. Ellsworth, Gregory C. Beroza Jan 1998

Observation Of The Seismic Nucleation Phase In The Ridgecrest, California, Earthquake Sequence, William L. Ellsworth, Gregory C. Beroza

United States Geological Survey: Staff Publications

Near-source observations of five M 3.8-5.2 earthquakes near Ridgecrest, California are consistent with the presence of a seismic nucleation phase. These earthquakes start abruptly, but then slow or stop before rapidly growing again toward their maximum rate of moment release. Deconvolution of instrument and path effects by empirical Green's functions demonstrates that the initial complexity at the start of the earthquake is a source effect. The rapid growth of the P-wave arrival at the start of the seismic nucleation phase supports the conclusion of Mori and Kanamori [1996] that these earthquakes begin without a magnitude-scaled slow initial phase of the …

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