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1998

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Articles 1441 - 1470 of 2574

Full-Text Articles in Physical Sciences and Mathematics

Resource Use In The Trinational Sangha River Region Of Equatorial Africa: Histories, Knowledge Forms, And Institutions, Heather E. Eves, Rebecca Hardin, Stephanie Rupp Jan 1998

Resource Use In The Trinational Sangha River Region Of Equatorial Africa: Histories, Knowledge Forms, And Institutions, Heather E. Eves, Rebecca Hardin, Stephanie Rupp

Yale School of the Environment Bulletin Series

This volume is based on an international conference, “Natural Resource Use Relations in the Trinational Sangha River Region of the Northwest Congo Basin,” held at Yale University in September 1997. In recognition of the bilingual context in which conservation occurs in the three countries of the Sangha region — Cameroon, Central African Republic, and Congo — all sessions of the conference were conducted simultaneously in French and English. This publication, which is a complete rendering of the conference papers and discussion sessions, is available in its entirety in both French and English.

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A Yoneda Description Of The Steenrod Operations, Robert R. Bruner Jan 1998

A Yoneda Description Of The Steenrod Operations, Robert R. Bruner

Mathematics Faculty Research Publications

No abstract provided.

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Some Root Invariants And Steenrod Operations In Ext_A(F2,F2), Robert R. Bruner Jan 1998

Some Root Invariants And Steenrod Operations In Ext_A(F2,F2), Robert R. Bruner

Mathematics Faculty Research Publications

We give the results of computations of root invariants in Ext over the Steenrod algebra through the 25-stem, with partial information through the 45-stem. This allows the computation of some new Steenrod operations as well.

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Some Remarks On The Root Invariant, Robert R. Bruner Jan 1998

Some Remarks On The Root Invariant, Robert R. Bruner

Mathematics Faculty Research Publications

We show how the root invariant of a product depends upon the product of the root invariants, give some examples of the equivariant definition of the root invariant, and verify a weakened form of the algebraic Bredon-Löffler conjecture.

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Narrow Hybrid Zone Between Two Subspecies Of Big Sagebrush (Artemisia Tridentata: Aeteraceae). V. Soil Properties, Han Wang, David W. Byrd, Jeffrey L. Howard, E. Durant Mcarthur, John H. Graham, D. Carl Freeman Jan 1998

Narrow Hybrid Zone Between Two Subspecies Of Big Sagebrush (Artemisia Tridentata: Aeteraceae). V. Soil Properties, Han Wang, David W. Byrd, Jeffrey L. Howard, E. Durant Mcarthur, John H. Graham, D. Carl Freeman

Environmental Science and Geology Faculty Research Publications

We studied soils of the big sagebrush (Artemisia tridentata) hybrid zone at two locations in Utah. The elemental composition, depth, and pH of soil in the basin and mountain big sagebrush habitats differed significantly from each other and from the hybrid zone soil. The hybrid zone soil is not just a simple blend of the two parental habitat soils. Rather, it possesses novel characteristics found in neither parental habitat and is more variable than the parental habitat soils. Correspondence analyses show that the sites occupied by each parental taxon are chemically distinct. Moreover, the principal axes from the two study …

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Radicals, Metals And Magnetism, David J R Brook Jan 1998

Radicals, Metals And Magnetism, David J R Brook

Faculty Publications

The interaction between unpaired electrons governs many physical properties of materials. Although in a fundamental sense the interaction is simple, a full understanding of the interaction in molecular systems is complicated by the presence of other bonding and non-bonding electrons. The resulting many body problem is very challenging. Nevertheless, much qualitative understanding can be obtained from applying simple molecular orbital theory and considering only the partly filled orbitals. The resulting model can be used to describe existing diradical and metal-radical systems and also has predicative value in the search for molecular magnets and design of nanoscale devices.

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Patterns On Liquid Surfaces: Cnoidal Waves, Compactons And Scaling, Andrei Ludu Jan 1998

Patterns On Liquid Surfaces: Cnoidal Waves, Compactons And Scaling, Andrei Ludu

Andrei Ludu

Localized patterns and nonlinear oscillation formation on the bounded free surface of an ideal incompressible liquid are analytically investigated. Cnoidal modes, solitons and compactons, as traveling non-axially symmetric shapes are discussed. A finite-difference differential generalized Korteweg-de Vries equation is shown to describe the three-dimensional motion of the fluid surface and the limit of long and shallow channels one re-obtains the well-known KdV equation. A tentative expansion formula for the representation of the general solution of a nonlinear equation, for given initial condition is introduced on a graphical-algebraic basis. The model is useful in multilayer fluid dynamics, cluster formation, and nuclear …

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Wavelets And Quantum Algebras, Andrei Ludu Jan 1998

Wavelets And Quantum Algebras, Andrei Ludu

Andrei Ludu

No abstract provided.

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Emisja Zanieczyszczeń Ze Spalania Odpadów Niebezpiecznych W Piecu Obrotowym, Robert Oleniacz, Marian Mazur, Marek Bogacki Jan 1998

Emisja Zanieczyszczeń Ze Spalania Odpadów Niebezpiecznych W Piecu Obrotowym, Robert Oleniacz, Marian Mazur, Marek Bogacki

Robert Oleniacz

The article presents measurement results of air pollutant emissions from incineration of selected hazardous wastes in a full-scale rotary kiln equipped with afterburner and a wet installation for flue gas cleaning. This type of kiln is suitable for thermal disposal of many sorts of wastes, both solid and liquid. Four groups of waste were being incinerated during the tests: coke tars, medical (hospital) and pharmaceutical wastes added to greased cleaning materials, a sawdust and used gloves, varnish and lubrication wastes, as well as waste rubber and resins. The study was performed in order to answer the question: is the process …

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Diffusion Of Low Molecular Mass Substances In Glassy Polymers, Sergey Sobolev Jan 1998

Diffusion Of Low Molecular Mass Substances In Glassy Polymers, Sergey Sobolev

Sergey Sobolev

No abstract provided.

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Intracellular Coexpression Of Epidermal Growth Factor Receptor, Her-2/Neu, And P21ras In Human Breast Cancers: Evidence For The Existence Of Distinctive Patterns Of Genetic Evolution That Are Common To Tumors From Different Patients, Stanley E. Shackney, Agnese A. Pollice, Charles A. Smith, Laura E. Janocko, Lillian Sweeney, Kathryn A. Brown, Sarita G. Singh, Lingping Gu, Robert Yakulis, Joseph F. Lucke Jan 1998

Intracellular Coexpression Of Epidermal Growth Factor Receptor, Her-2/Neu, And P21ras In Human Breast Cancers: Evidence For The Existence Of Distinctive Patterns Of Genetic Evolution That Are Common To Tumors From Different Patients, Stanley E. Shackney, Agnese A. Pollice, Charles A. Smith, Laura E. Janocko, Lillian Sweeney, Kathryn A. Brown, Sarita G. Singh, Lingping Gu, Robert Yakulis, Joseph F. Lucke

Joseph Lucke

Multiparameter flow cytometry studies were performed on cells from the primary tumors of 94 patients with breast cancer. Correlated cellular measurements of cell DNA content, Her-2/neu, epidermal growth factor receptor (EGFR), and p21ras levels were performed on each of 5,000 to 100,000 cells from each tumor. When criteria for positivity were matched with those in common use for immunohistochemical studies, 28 of 94 (30\%) breast cancers were classified as positive for Her-2/neu overexpression. When similar criteria were applied to the EGFR measurements, 23 of 94 (24\%) cases were classified as positive for EGFR overexpression. Similarly, 23 of 94 (24\%) cases …

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Mass Transfer With Chemical Reaction In The Process Of Ammonia Desorption From Aqueous Solutions Containing Carbon Dioxide, Wojciech M. Budzianowski Jan 1998

Mass Transfer With Chemical Reaction In The Process Of Ammonia Desorption From Aqueous Solutions Containing Carbon Dioxide, Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

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Archiv Der Pharmazie, Philadelphia University Jan 1998

Archiv Der Pharmazie, Philadelphia University

Philadelphia University, Jordan

No abstract provided.

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Simulation And Fpga Implementation Of A Simple Computer, Philadelphia University Jan 1998

Simulation And Fpga Implementation Of A Simple Computer, Philadelphia University

Philadelphia University, Jordan

No abstract provided.

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Sustainable Development As A Framework For National Governance, John C. Dernbach Jan 1998

Sustainable Development As A Framework For National Governance, John C. Dernbach

John C. Dernbach

No abstract provided.

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Reflections On Comparative Law, Environmental Law, And Sustainability, John C. Dernbach Jan 1998

Reflections On Comparative Law, Environmental Law, And Sustainability, John C. Dernbach

John C. Dernbach

No abstract provided.

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Local Structural Heterogeneities In Liquid Water Under Pressure, M. Canpolat, Francis W. Starr, M. R.S. Lahijany, A. Scala, O. Mishima, S. Havlin, H. E. Stanley Jan 1998

Local Structural Heterogeneities In Liquid Water Under Pressure, M. Canpolat, Francis W. Starr, M. R.S. Lahijany, A. Scala, O. Mishima, S. Havlin, H. E. Stanley

Francis Starr

No abstract provided.

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Species Delineation And The Identification Of Evolutionarily Significant Units: Lessons From The Freshwater Mussel Genus Potamilus (Bivalvia: Unionidae), Kevin J. Roe, Charles Lydeard Jan 1998

Species Delineation And The Identification Of Evolutionarily Significant Units: Lessons From The Freshwater Mussel Genus Potamilus (Bivalvia: Unionidae), Kevin J. Roe, Charles Lydeard

Kevin J. Roe

Accurate identification of biological entities is critical to the timely and efficient preservation of biodiversity. Concepts that define segments of biological diversity--species and evolutionarily significant units (ESUs)--should reflect our current knowledge of the biological world. Conflation of different hierarchical definitions of taxa has the potential to obscure distinct biological entities in need of protection. The concept of the ESU has been criticized because it includes within its definition distinct biological entities that otherwise would be recognized as species. Herein we evaluate several versions of the evolutionary significant unit concept and provide as a case study an analysis of geographic variation …

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The Role Of Ligand Flexibility In Predicting Biological Activity: Structure–Activity Relationships For Aryl Hydrocarbon, Estrogen, And Androgen Receptor Binding Affinity, Steven P. Bradbury, Ovanes G. Mekenyan, Gerald T. Ankley Jan 1998

The Role Of Ligand Flexibility In Predicting Biological Activity: Structure–Activity Relationships For Aryl Hydrocarbon, Estrogen, And Androgen Receptor Binding Affinity, Steven P. Bradbury, Ovanes G. Mekenyan, Gerald T. Ankley

Steven P. Bradbury

Recent studies indicate that the potency and agonist or antagonist activity of steroid hormone ligands are dependent, in part, on ligand–receptor binding affinity as well as the conformation of the ligand–receptor complex. The binding of ligands to hormone receptors is thought to involve interactions by which shapes of both the receptor and ligand are modified in the formation of the ligand–receptor complex. As a consequence, it is essential to explore the significance of ligand flexibility in the development of screening-level structure–activity relationships. In this review, examples are provided of techniques used to generate and screen ligand conformers in the development …

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Ridgetop Splitting, Spreading, And Shattering Related To Earthquakes In Southern California, James P. Mccalpin Jan 1998

Ridgetop Splitting, Spreading, And Shattering Related To Earthquakes In Southern California, James P. Mccalpin

James P. McCalpin

Our mapping documents that anomalous ridgetop landforms are numerous in the San Gabriel and Santa Susana Mountains, and that many sites (37% of the San Gabriel sites, 16% of the Santa Susana sites) are not associated with any visible signs of landsliding. These sites may represent deep-seated gravitational spreading due to earthquake shaking. However, our factor analysis indicates that the spatial distribution of these suspected spreading landforms, with respect to ridge relief and distance to Late Quaternary faults, is essentially identical to that of landslides. Thus, it seems that if these spreading landforms represent the results of earthquake shaking, than …

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Statistics Of Paleoseismic Data, James P. Mccalpin Jan 1998

Statistics Of Paleoseismic Data, James P. Mccalpin

James P. McCalpin

Compiled data from numerous neotectonic-geomorphic and trench studies reveals patterns in the spatial and temporal variation of coseismic fault displacement. Recurrence intervals between successive large earthquakes on faults define a near-symmetrical probability distribution with a coefficient of variance of 0.36. Normal faults have the most regular recurrence, and subduction zones the most variable. Variability in recurrence times at a site is not dependent on the number of recurrence intervals dated at that site. During historic surface-rupturing earthquakes slip has varied widely along strike. Based on 56 ruptures where more than 15 displacement measurements were made, the generic pattern is for …

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Computational Evidence For A Free Silylium Ion, Thomas Müller, Yan Zhao, Joseph B. Lambert Jan 1998

Computational Evidence For A Free Silylium Ion, Thomas Müller, Yan Zhao, Joseph B. Lambert

Yan Zhao

Ab initio calculations are the method of choice to gain an insight into the structure and properties of silylium ions, especially when an X-ray structure cannot be obtained, as in the case of trimesitylsilylium (1). The computed structures and properties of triarylsilylium ions suggest that 1 is the first free silylium ion prepared in the condensed phase.

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Nature Of 60Μm Emission In 3c 47, 3c 207 And 3c 334, Ilse M. Van Bemmel, Peter D. Barthel, Min S. Yun Jan 1998

Nature Of 60Μm Emission In 3c 47, 3c 207 And 3c 334, Ilse M. Van Bemmel, Peter D. Barthel, Min S. Yun

Min S. Yun

We try to explain the unusually high far-infrared emission seen by IRAS in the double-lobed radio-loud quasars 3C 47, 3C 207 and 3C 334. High resolution cm–mm observations were carried out to determine their radio core spectra, which are subsequently extrapolated to the far-infrared in order to determine the strength of the synchrotron far-infrared emission. The extrapolated flux densities being considerably lower than the observed values, a significant nonthermal far-infrared component is unlikely in the case of 3C 47 and 3C 334. However, this component could be responsible for the far-infrared brightness of 3C 207. Our analysis demonstrates that nonthermal …

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Effects Of Interaction Induced Activities In Hickson Compact Groups: Co And Fir Study, L Verdes-Montenegro, Min S. Yun, J Perea, A Del Olmo, P T P Ho Jan 1998

Effects Of Interaction Induced Activities In Hickson Compact Groups: Co And Fir Study, L Verdes-Montenegro, Min S. Yun, J Perea, A Del Olmo, P T P Ho

Min S. Yun

A study of 2.6 mm CO J = 1 → 0 and far-infrared (FIR) emission in a distance-limited (z < 0.03) complete sample of Hickson compact group (HCG) galaxies was conducted in order to examine the effects of their unique environment on the interstellar medium of component galaxies and to search for a possible enhancement of star formation and nuclear activity. Ubiquitous tidal interactions in these dense groups would predict enhanced activities among the HCG galaxies compared to isolated galaxies. Instead, their CO and FIR properties (thus, "star formation efficiency") are surprisingly similar to isolated spirals. The CO data for 80 HCG galaxies presented here (including 10 obtained from the literature) indicate that the spirals globally show the same H2 content as the isolated comparison sample, although 20% are deficient in CO emission. Because of their large optical luminosity, low metallicity is not likely the main cause for the low CO luminosity. The CO deficiency appears linked with the group evolution, and gas exhaustion through past star formation and removal of the external gas reserve by tidal stripping of the outer H I disk offer a possible explanation. The IRAS data for the entire redshift-limited complete sample of 161 HCG galaxies were reanalyzed using ADDSCAN/SCANPI, improving the sensitivity by a factor of 3-5 over the existing Point Source Catalog (PSC) and resolving better the contribution from individual galaxies. The new analysis of the IRAS data confirms the previous suggestion that FIR emission in HCG galaxies is similar to isolated, Virgo Cluster, and weakly interacting galaxies. Their H2 and FIR characteristics yield a star formation efficiency that is similar to that of these comparison samples. A factor 2 enhancement in the 25-100 μm flux ratio among the HCG spirals is found, which suggests intense localized nuclear starburst activity similar to that of H II galaxies. A number of early-type galaxies in HCGs are detected in CO and FIR, lending further support to the idea that tidal interactions and tidally induced evolution of the groups and member galaxies are important in our sample.

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33. Noburo Yamazaki, Otto Vogl, Seiichi Nakahama Jan 1998

33. Noburo Yamazaki, Otto Vogl, Seiichi Nakahama

Otto Vogl

No abstract provided.

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Deep Water Formation And Poleward Ocean Heat Transport In The Warm Climate Extreme Of The Cretaceous (80 Ma), Esther C. Brady, Robert M. Deconto, Starley L. Thompson Jan 1998

Deep Water Formation And Poleward Ocean Heat Transport In The Warm Climate Extreme Of The Cretaceous (80 Ma), Esther C. Brady, Robert M. Deconto, Starley L. Thompson

Robert M DeConto

An ocean simulation of the “greenhouse” climate of the Late Cretaceous, about 80 million years ago (Ma), demonstrates that warm salty deep water, consistent with proxy climate data, can be formed by cooling in the high latitude Southern Hemisphere. This is contrary to the long standing hypothesis of deep water formation due to evaporation over low latitude marginal seas. A reduced equator to pole temperature gradient is maintained with a poleward ocean heat transport that is not larger than today's.

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On Distortion And Thickness Of Knots, Robert B. Kusner, John M. Sullivan Jan 1998

On Distortion And Thickness Of Knots, Robert B. Kusner, John M. Sullivan

Robert Kusner

What length of rope (of given diameter) is required to tie a particular knot? Or, to turn the problem around, given an embedded curve, how thick a regular neighborhood of the curve also is embedded? Intuitively, the diameter of the possible rope is bounded by the distance between strands at the closest crossing in the knot. But of course the distance between two points along a curve goes to zero as the points approach each other, so to make the notion precise, we need to exclude some neighborhood of the diagonal.

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Ionic Hydrogen Bonds In Bioenergetics. 3. Proton Transport In Membranes, Modeled By Ketone/Water Clusters, Michael Meot-Ner, Steve Scheiner, Edward Yu Jan 1998

Ionic Hydrogen Bonds In Bioenergetics. 3. Proton Transport In Membranes, Modeled By Ketone/Water Clusters, Michael Meot-Ner, Steve Scheiner, Edward Yu

Edward Yu

Hydrogen bond networks in protonated acetone/water clusters are stabilized by H3O+(Me2CO)2 centers, and the stabilizaton increases with further acetone content. For example, proton transfer from neat water (H2O)6H+ clusters to form mixed (Me2CO)3(H2O)3H+ clusters is exothermic by 80 kJ/mol (19 kcal/mol), due to strong hydrogen bonding of the carbonyl groups; in a series of mixed clusters B3(H2O)3H+, the stability of the hydrogen bond network correlates with the proton affinities PA(B). In diketone models of adjacent peptide links, the proton is stabilized by internal hydrogen bonds between the carbonyl groups. The internal bonds can be significant, for example, 31 kJ/mol (7 …

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Evaluation Of Chloride And Pesticide Transport In A Fractured Clayey Till Using Large Undisturbed Columns And Numerical Modeling, Peter R. Jorgensen, Larry Mckay, Niels H. Spliid Jan 1998

Evaluation Of Chloride And Pesticide Transport In A Fractured Clayey Till Using Large Undisturbed Columns And Numerical Modeling, Peter R. Jorgensen, Larry Mckay, Niels H. Spliid

Larry McKay

Saturated groundwater flow and tracer experiments using fluorescent dye, chloride, and the herbicides mecoprop and simazine were carried out in the laboratory using three large-diameter (0.5 m) undisturbed columns of fractured clayey till. Hydraulic conductivity of the columns ranged from 10−5 m/s in the shallowest column (1 m dept)) to 10−7 m/s in the deepest column (4 m depth) and were similar to field-measured values for these deposits. Results of the tracer experiments are consistent with a conceptual model of advective transport along the fractures combined with diffusion into the fine-grained matrix between the fractures. Arrival of the chloride tracer …

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The Norm In Taxicab Geometry, Cumali̇ Eki̇ci̇, I. Kocayusufoğlu, Z. Akça Jan 1998

The Norm In Taxicab Geometry, Cumali̇ Eki̇ci̇, I. Kocayusufoğlu, Z. Akça

Turkish Journal of Mathematics

In this paper, we will define the inner-product and the norm in taxicab geometry and then we will discuss this inner-product geometrically.

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