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Articles 1291 - 1320 of 1413

Full-Text Articles in Physical Sciences and Mathematics

The Effects Of Buffer And Temperature Feedback On The Oceanic Uptake Of Co2, Chuixiang Yi, Peng Gong, Ming Xu, Ye Qi Mar 2001

The Effects Of Buffer And Temperature Feedback On The Oceanic Uptake Of Co2, Chuixiang Yi, Peng Gong, Ming Xu, Ye Qi

Publications and Research

The feedback between climate and carbon cycle systems is critical to the prediction of future CO2 concentration in the atmosphere and the capacity of the oceans to take up CO2 from the atmosphere. We calculated the magnitudes of the potential feedback between the increase of atmospheric CO2 concentration, the carbonate chemistry of the oceans (via a buffer factor), and the global temperature. We find that the magnitude of the buffer feedback depends strongly on the level of the dissolved inorganic carbon (DIC) in the oceans and increases rapidly with the increase of the atmospheric CO …


0920+3517_Nir_Spex, Maria Teresa Ruiz Mar 2001

0920+3517_Nir_Spex, Maria Teresa Ruiz

Publications and Research

No abstract provided.


What Is Environmental Literacy? (Book Review), Aldemaro Romero Jr. Jan 2001

What Is Environmental Literacy? (Book Review), Aldemaro Romero Jr.

Publications and Research

No abstract provided.


1237+6526_Opt_Lris, Adam J. Burgasser Jul 2000

1237+6526_Opt_Lris, Adam J. Burgasser

Publications and Research

No abstract provided.


Influence Of Advection On Measurements Of The Net Ecosystem-Atmosphere Exchange Of Co2 From A Very Tall Tower, Chuixiang Yi, Kenneth J. Davis, Peter S. Bakwin, Bernard W. Berger, Linsey C. Marr Apr 2000

Influence Of Advection On Measurements Of The Net Ecosystem-Atmosphere Exchange Of Co2 From A Very Tall Tower, Chuixiang Yi, Kenneth J. Davis, Peter S. Bakwin, Bernard W. Berger, Linsey C. Marr

Publications and Research

In most studies of the net ecosystem-atmosphere exchange of CO2 (NEE) using tower-based eddy covariance( EC) systems it has been assumed that advection is negligible. In this study we use a scalar conservation budget method to estimate the contribution of advection to NEE measurements from a very tall tower in northern Wisconsin. We examine data for June-August 1997. Measured NEEo, calculated as the sum of the EC flux plus the rate of change of storage below the EC measurement level, is expected to be constant with measurement height, and we take the differences between levels as a measure of …


We Need To Color Our Environment, Aldemaro Romero Jr. Jan 2000

We Need To Color Our Environment, Aldemaro Romero Jr.

Publications and Research

No abstract provided.


The Total Environmentalist, Aldemaro Romero Jr. Jan 2000

The Total Environmentalist, Aldemaro Romero Jr.

Publications and Research

No abstract provided.


The Unsung Heroes Of Speleology, Aldemaro Romero Jr., Kathryn Benz Jan 2000

The Unsung Heroes Of Speleology, Aldemaro Romero Jr., Kathryn Benz

Publications and Research

No abstract provided.


Level Adjusted Exponential Smoothing: A Method For Judgmentally Adjusting Exponential Smoothing Models For Planned Discontinuities, Dan Williams, Don Miller Jul 1999

Level Adjusted Exponential Smoothing: A Method For Judgmentally Adjusting Exponential Smoothing Models For Planned Discontinuities, Dan Williams, Don Miller

Publications and Research

Forecasters often make judgmental adjustments to exponential smoothing forecasts to account for the effects of a future planned change. While this approach may produce sound initial forecasts, it can result in diminished accuracy for forecast updates. A proposed technique lets the forecaster include policy change adjustments within an exponential smoothing model. For 20 real data series representing Virginia Medicaid expenses, initial forecasts and forecast updates are developed using the proposed technique and several alternatives, and they are updated through various simulated level shifts. The proposed technique was more accurate than the alternatives in updating forecasts when a shift in level …


Hydrothermal Sediments Associated With A Relict Back-Arc Spreading Center In The Shikoku Basin, Recovered From The Nankai Accretionary Prism, Japan, Jane L. Alexander, Kevin T. Pickering, Elizabeth H. Bailey Jun 1999

Hydrothermal Sediments Associated With A Relict Back-Arc Spreading Center In The Shikoku Basin, Recovered From The Nankai Accretionary Prism, Japan, Jane L. Alexander, Kevin T. Pickering, Elizabeth H. Bailey

Publications and Research

The hemipelagic mudrocks of the Nankai accretionary prism, Japan, contain hydrothermal deposits associated with a relict spreading center in the Shikoku Basin. Initial work on core samples from Ocean Drilling Program Site 808 found several samples with elevated concentrations of calcium, magnesium, iron and manganese, at depths of between 1060 and 1111 m below sea floor. However, the origin of these sediments was uncertain, due to a lack of data. There was no recorded evidence of whether these elevated concentrations were present throughout this interval of core, or if they were present as discrete layers with the background hemipelagic mudrocks …


Novel Carbon-Carbon Bond Oxidative Cleavage Of Hexabenzyl-Hexaazaisowurtzitane By N-Buono And (Nh4)2ce(No3)6, Xiao-Pei Guan, Hong Yan, Jian-Guang Sun, Yong-Zhong Yu Mar 1999

Novel Carbon-Carbon Bond Oxidative Cleavage Of Hexabenzyl-Hexaazaisowurtzitane By N-Buono And (Nh4)2ce(No3)6, Xiao-Pei Guan, Hong Yan, Jian-Guang Sun, Yong-Zhong Yu

Publications and Research

Treatment of 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazatetracyclo-[5.5.0.05,9.03,11]dodecane with n-butyl nitrite or ammonium cerium nitrate results in novel C(1)-C(7) oxidative cleavage to give 1,3,4,5,7,8-hexabenzyl-cis-cisoid-cis-hexahydro-1H,5H-diimidazolinium[4,5-b:4′,5′-e]pyrazine dinitrate.


Research And Implementation Of Integrated Concurrent Software Development Environment Based On Object-Oriented Petri Nets, Jinzhong Niu Feb 1999

Research And Implementation Of Integrated Concurrent Software Development Environment Based On Object-Oriented Petri Nets, Jinzhong Niu

Publications and Research

While network technologies and environments get more and more popular, the demand for concurrent systems becomes stronger and stronger. But the characteristics of concurrency make it difficult to develop them.

This dissertation combines Object-Oriented technology and Petri Nets theory, and put forth OOPN (OO Petri Nets) model to describe concurrent systems. Based on the research of conventional development methods of concurrent software, this article advances a new one, which integrates specification, validation and auto-generating codes. Accordingly, an integrated development environment for concurrent software, i.e., OOPN-IDE, comes into being, which mainly includes the following four tools: the concurrent system modeling tool …


So, How Green Is Your Label?, Aldemaro Romero Jr. Jan 1999

So, How Green Is Your Label?, Aldemaro Romero Jr.

Publications and Research

No abstract provided.


On C^1 Robust Singular Transitive Sets For Three-Dimensional Flows, Carlos Arnoldo Morales, Maria José Pacífico, Enrique Ramiro Pujals Jan 1998

On C^1 Robust Singular Transitive Sets For Three-Dimensional Flows, Carlos Arnoldo Morales, Maria José Pacífico, Enrique Ramiro Pujals

Publications and Research

Abstract:

The main goal of this paper is to study robust invariant transitive sets containing singularities for C1 flows on three-dimensional compact boundaryless manifolds:they are partially hyperbolic with volume expanding central direction. Moreover, they are either attractors or repellers. Robust here means that this property cannot be destroyed by small C1-perturbations of the flow.

Résumé:

Le but de ce travail est d'étudier des ensembles invariants robustes ayant des singularités pour des flots C1 sur des variétés tridimensionelles : ce sont des ensembles hyperboliques singuliers. << Robuste >> veut dire ici que cette propriété ne peut être détruite par des …


Microanalytical Investigations Of Gold-Bearing Rocks From The An Najadi Region In Saudi Arabia, Nazrul I. Khandaker, M. Ahmed, M. M. Hariri, M. A. Garwan, K. R. Khan, M. M. Al-Ohali Jul 1997

Microanalytical Investigations Of Gold-Bearing Rocks From The An Najadi Region In Saudi Arabia, Nazrul I. Khandaker, M. Ahmed, M. M. Hariri, M. A. Garwan, K. R. Khan, M. M. Al-Ohali

Publications and Research

The Proton Induced X-ray Emission technique with a scanning microbeam (micro-PIXE) and Scanning Electron Microscopy (SEM) were employed to study gold-bearing rocks from the An Najadi and adjacent regions situated within the exposed northeastern part of the Arabian Shield. These microanalytical investigations, together with routine petrological and ore microscopic studies, demonstrated the presence of important partitioning of major minerals and trace elements in several samples. These measurements also revealed microstructural features including brecciation within quartz grains and metal concentrations within these fracture-controlled micro-conduits. Results showed promise in terms of using distinctive geochemical signatures for ore body recognition. Of particular interest …


Charles Hugh Callison, John A. Drobnicki Jan 1997

Charles Hugh Callison, John A. Drobnicki

Publications and Research

Charles Hugh Callison helped turn the National Audubon Society into a significant wildlife advocacy organization.


Thomas Mayo Brewer, John A. Drobnicki Jan 1997

Thomas Mayo Brewer, John A. Drobnicki

Publications and Research

Thomas Mayo Brewer was an ornithologist, oologist, and publisher whose work was concerned with eggshells as well as the breeding habits, life histories, and geographical distribution of birds.

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Edward Augustus Bowers, John A. Drobnicki Jan 1997

Edward Augustus Bowers, John A. Drobnicki

Publications and Research

Edward Augustus Bowers was a lawyer, government employee, and conservationist whose work in government service brought about the creation of national forests that would be managed in the public interest.


Karl Patterson Schmidt, John A. Drobnicki Jan 1997

Karl Patterson Schmidt, John A. Drobnicki

Publications and Research

Karl Patterson Schmidt turned herpetology firom a hobby into a branch of biology, and influenced numerous young biologists as an editor, teacher, author, and curator.


Merritt Lyndon Fernald, John A. Drobnicki Jan 1997

Merritt Lyndon Fernald, John A. Drobnicki

Publications and Research

Merritt Lyndon Fernald trained the future leaders in taxonomy and descriptive botany and helped maintain a high level in botanical writing through his work as editor of Rhodora.


Global Attractors From The Explosion Of Singular Cycles, Carlos Arnoldo Morales, Maria José Pacífico, Enrique Ramiro Pujals Jan 1997

Global Attractors From The Explosion Of Singular Cycles, Carlos Arnoldo Morales, Maria José Pacífico, Enrique Ramiro Pujals

Publications and Research

Abstract:

In this paper we announce recent results on the existence and bifurcations of hyperbolic systems leading to non-hyperbolic global attractors.

Résumé:

Nous présentons dans cette Note des résultats récents concernant l’existence et les bifurcations d’un nouvel attracteur global chaotique.


Study Of Volcanic Sediments By Microbeam-Pixe Technique, Nazrul I. Khandaker, M. Ahmed, M. A. Garwan Apr 1996

Study Of Volcanic Sediments By Microbeam-Pixe Technique, Nazrul I. Khandaker, M. Ahmed, M. A. Garwan

Publications and Research

Single mineral grains in a suite of Cretaceous (85–90 Ma) volcanic sedimentary rocks were analyzed using the microbeam-PIXE technique to understand fundamental geological processes responsible for micro-scale variation in elemental composition across mineral zones, twinning, cleavage planes, fractures and grain boundaries. Distributions of major and trace elements show distinct geochemical features indicative of a specific geological setting and a subsequent diagenetic process in these volcanic sediments. Examples of mineral zoning, microstructures of variable chemistry and post-depositional fluid flow are discussed using the data on feldspar group of minerals.


Stochastic Approximation Methods For Systems Over An Infinite Horizon, Harold J. Kushner, Felisa Vázquez-Abad Mar 1996

Stochastic Approximation Methods For Systems Over An Infinite Horizon, Harold J. Kushner, Felisa Vázquez-Abad

Publications and Research

The paper develops efficient and general stochastic approximation (SA) methods for improving the operation of parametrized systems of either the continuous- or discrete-event dynamical systems types and which are of interest over a long time period. For example, one might wish to optimize or improve the stationary (or average cost per unit time) performance by adjusting the systems parameters. The number of applications and the associated literature are increasing at a rapid rate. This is partly due to the increasing activity in computing pathwise derivatives and adapting them to the average-cost problem. Although the original motivation and the examples come …


Performance Indices For On-Ice Hockey Statistics, William (Bill) H. Williams Aug 1995

Performance Indices For On-Ice Hockey Statistics, William (Bill) H. Williams

Publications and Research

No abstract provided.


Careers In Chemical Information And Science Librarianship, Philip Barnett Aug 1994

Careers In Chemical Information And Science Librarianship, Philip Barnett

Publications and Research

The ceaseless growth of chemical information has created a need for chemical professionals who can organize and disseminate this vast knowledge. If you like to read, enjoy being in a library, or like to work with information on computers, you may want to consider a career in chemical information. While only a small fraction of chemists choose this nontraditional career, they have found fulfillment in many different roles. Chemical information scientists and librarians using the powerful computerized databases now available either provide chemists and other research scientists the information they need, or teach researchers and students how to use these …


Contaminación De Las Aguas, Aldemaro Romero Jr., Ana Mayayo Jan 1993

Contaminación De Las Aguas, Aldemaro Romero Jr., Ana Mayayo

Publications and Research

No abstract provided.


Las Consecuencias Ambientales De La Guerra, Aldemaro Romero Jr. Jan 1993

Las Consecuencias Ambientales De La Guerra, Aldemaro Romero Jr.

Publications and Research

No abstract provided.


Desechos Sólidos, Aldemaro Romero Jr., Ana Mayayo Jan 1993

Desechos Sólidos, Aldemaro Romero Jr., Ana Mayayo

Publications and Research

No abstract provided.


El Agua: El Recurso Peor Manejado, Aldemaro Romero Jr. Jan 1993

El Agua: El Recurso Peor Manejado, Aldemaro Romero Jr.

Publications and Research

No abstract provided.


Parque Nacional Sierra La Culata, Aldemaro Romero Jr. Jan 1992

Parque Nacional Sierra La Culata, Aldemaro Romero Jr.

Publications and Research

No abstract provided.