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2002

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Articles 2011 - 2040 of 3435

Full-Text Articles in Physical Sciences and Mathematics

Tr-2002004: On The Effectiveness Of Tangible Interfaces In Collaborative Learning Environments, Lori L. Scarlatos, Shalva S. Landy, Julia Breban, Robin Horowitz, Chanie Sandberg Jan 2002

Tr-2002004: On The Effectiveness Of Tangible Interfaces In Collaborative Learning Environments, Lori L. Scarlatos, Shalva S. Landy, Julia Breban, Robin Horowitz, Chanie Sandberg

Computer Science Technical Reports

No abstract provided.


Tr-2002001: Can We Optimize Toeplitz/Hankel Computations?, V. Y. Pan Jan 2002

Tr-2002001: Can We Optimize Toeplitz/Hankel Computations?, V. Y. Pan

Computer Science Technical Reports

No abstract provided.


Tr-2002007: Ubiquitous Puzzle Pieces: 3d Tangible Interfaces For Collaborative Learning Environments, Lori L. Scarlatos, Shalva S. Landy, Saira Qureshi Jan 2002

Tr-2002007: Ubiquitous Puzzle Pieces: 3d Tangible Interfaces For Collaborative Learning Environments, Lori L. Scarlatos, Shalva S. Landy, Saira Qureshi

Computer Science Technical Reports

No abstract provided.


Tr-2002002: Can We Optimize Toeplitz/Hankel Computations? Ii. Singular Toeplitz/Hankel-Like Case, V. Y. Pan Jan 2002

Tr-2002002: Can We Optimize Toeplitz/Hankel Computations? Ii. Singular Toeplitz/Hankel-Like Case, V. Y. Pan

Computer Science Technical Reports

No abstract provided.


Tr-2002008: Investigation Of The Sensitivity Of The Monte Carlo Solution For The Barker-Ferry Equation Using Different Sequential And Parallel Pseudo-Random Number Generators, T. V. Gurov, P. A. Whitlock Jan 2002

Tr-2002008: Investigation Of The Sensitivity Of The Monte Carlo Solution For The Barker-Ferry Equation Using Different Sequential And Parallel Pseudo-Random Number Generators, T. V. Gurov, P. A. Whitlock

Computer Science Technical Reports

No abstract provided.


Tr-2002010: Programming Finite-Domain Constraint Propagators In Action Rules, Neng-Fa Zhou Jan 2002

Tr-2002010: Programming Finite-Domain Constraint Propagators In Action Rules, Neng-Fa Zhou

Computer Science Technical Reports

No abstract provided.


Tr-2002011: Corpus-Based Ambiguity Resolution Of Biomedical Terms Using Knowledge Bases And Machine Learning, Hongfang Liu Jan 2002

Tr-2002011: Corpus-Based Ambiguity Resolution Of Biomedical Terms Using Knowledge Bases And Machine Learning, Hongfang Liu

Computer Science Technical Reports

No abstract provided.


Tr-2002018: How Frequently Is A Matrix Nonsingular?, Xinmao Wang Jan 2002

Tr-2002018: How Frequently Is A Matrix Nonsingular?, Xinmao Wang

Computer Science Technical Reports

No abstract provided.


Tr-2002019: Improved Algorithms For Computing Determinants And Resultants, Ioannis Z. Emiris, Victor Y. Pan Jan 2002

Tr-2002019: Improved Algorithms For Computing Determinants And Resultants, Ioannis Z. Emiris, Victor Y. Pan

Computer Science Technical Reports

No abstract provided.


Tr-2002020: Inverse Power And Durand-Kerner Iterations For Univariate Polynomial Root-Finding, D. A. Bini, L. Gemignani, V. Y. Pan Jan 2002

Tr-2002020: Inverse Power And Durand-Kerner Iterations For Univariate Polynomial Root-Finding, D. A. Bini, L. Gemignani, V. Y. Pan

Computer Science Technical Reports

No abstract provided.


Tr-2002015: Residual Correction Algorithms For General And Structured Matrices, V. Y. Pan, M. Kunin, R. E. Rosholt, H. Cebecioglu Jan 2002

Tr-2002015: Residual Correction Algorithms For General And Structured Matrices, V. Y. Pan, M. Kunin, R. E. Rosholt, H. Cebecioglu

Computer Science Technical Reports

No abstract provided.


A Density Property Of The Tori And Duality, Peter Loth Jan 2002

A Density Property Of The Tori And Duality, Peter Loth

Mathematics Faculty Publications

In this note, a short proof of a recent theorem of D. Dikranjan and M. Tkachenko is given, and their result is extended.


When Is Rain Steady?, A. R. Jameson, Alexander Kostinski Jan 2002

When Is Rain Steady?, A. R. Jameson, Alexander Kostinski

Department of Physics Publications

By definition, steady rain should have a nearly constant rainfall rate. Thus far, however, the criteria for determining when rain is steady remain qualitative and arbitrary. The authors suggest a definition for steadiness that can be used to quantify the elusive notion of natural variability. In particular, the logical criteria for steadiness imply statistical stationarity and lack of correlation between raindrops in neighboring volumes, requirements identical to those for the drops being distributed according to a Poisson process at all scales. Hence, steady rain is Poissonian. Explicit equations for the variance of the rainfall rates are developed. They show that, …


Stable-Isotopic Composition Of Precipitation Over The Northern Slope Of The Central Himalaya, Shichang Kang, Karl J. Kreutz, Paul Andrew Mayewski, Dahe Qin, Tandong Yao Jan 2002

Stable-Isotopic Composition Of Precipitation Over The Northern Slope Of The Central Himalaya, Shichang Kang, Karl J. Kreutz, Paul Andrew Mayewski, Dahe Qin, Tandong Yao

Earth Science Faculty Scholarship

Stable-water-isotope data (deltaD and delta(18)O) from three groups of samples (fresh-snow and snow-pit samples collected on Qomolangma (Mount Everest) and Xixabangma during field seasons 1997,1998 and 2001, and precipitation samples collected at Tingri station during summer 2000) are presented and used to survey the isotopic composition of precipitation over the northern slope of the central Himalaya. Multi-year snow-pit samples on Qomolangma have a local meteoric water-line (slope = 8) close to the global value. Deuterium excess (d = deltaD - 8delta(18)O) values at Tingri are much lower than those in fresh snow from Qomolangma, probably due to differences in moisture …


Antarctic Volcanic Flux Ratios From Law Dome Ice Cores, Anne S. Palmer, Vin I. Morgan, Mark A.J. Curran, Tas D. Van Ommen, Paul Andrew Mayewski Jan 2002

Antarctic Volcanic Flux Ratios From Law Dome Ice Cores, Anne S. Palmer, Vin I. Morgan, Mark A.J. Curran, Tas D. Van Ommen, Paul Andrew Mayewski

Earth Science Faculty Scholarship

Explosive volcanic eruptions can inject large quantities of sulphur dioxide into the stratosphere. The aerosols that result from oxidation of the sulphur dioxide can produce significant cooling of the troposphere by reflecting or absorbing solar radiation. It is possible to obtain an estimate of the relative stratospheric sulphur aerosol concentration produced by different volcanoes by comparing sulphuric acid fluxes determined by analysis of polar ice cores. Here, we use a non-sea-salt sulphate time series derived from three well-dated Law Dome ice cores to investigate sulphuric acid flux ratios for major eruptions over the period AD 1301-1995. We use additional data …


Local Rates Of Ice-Sheet Thickness Change In Greenland, Gordon S. Hamilton, Ian M. Whillans Jan 2002

Local Rates Of Ice-Sheet Thickness Change In Greenland, Gordon S. Hamilton, Ian M. Whillans

Earth Science Faculty Scholarship

The rate of ice-sheet thickness change is calculated for 10 sites in Greenland by comparing measured values of ice vertical velocity and snow-accumulation rate. Vertical velocities are derived from repeat surveys of markers using precision global positioning system techniques, and accumulation rates are determined from stratigraphic analysis of firn cores. The results apply to time-scales covered by the firn-core records, which in most cases are a few decades. A spectrum of thickness-change rates is obtained, ranging from substantial thinning to slow thickening. The sites where ice-sheet thinning is indicated are located near the ice-sheet margin or in outlet glacier catchments. …


Mass Balance And Accumulation Rate Across Siple Dome, West Antarctica, Gordon S. Hamilton Jan 2002

Mass Balance And Accumulation Rate Across Siple Dome, West Antarctica, Gordon S. Hamilton

Earth Science Faculty Scholarship

Snow-accumulation rates and rates of ice-thickness change (mass balance) are studied at several sites on Siple Dome, West Antarctica. Accumulation rates are derived from analyses of gross beta radioactivity in shallow firn cores located along a 60 km transect spanning both flanks and the crest of the dome. There is a north-south gradient in snow-accumulation rate across the dome that is consistent with earlier radar mapping of internal stratigraphy. Orographic processes probably control this distribution. Mass balance is inferred from the difference between global positioning system (GPS)-derived vertical velocities and snow-accumulation rates for sites close to the firn-core locations. Results …


Post-Depositional Movement Of Methanesulphonic Acid At Law Dome, Antarctica, And The Influence Of Accumulation Rate, Mark A.J. Curran, Anne S. Palmer, Tas D. Van Ommen, Vin I. Morgan, Katrina L. Phillips, Alison J. Mcmorrow, Paul Andrew Mayewski Jan 2002

Post-Depositional Movement Of Methanesulphonic Acid At Law Dome, Antarctica, And The Influence Of Accumulation Rate, Mark A.J. Curran, Anne S. Palmer, Tas D. Van Ommen, Vin I. Morgan, Katrina L. Phillips, Alison J. Mcmorrow, Paul Andrew Mayewski

Earth Science Faculty Scholarship

A series of ice cores from sites with different snow-accumulation rates across Law Dome, East Antarctica, was investigated for methanesulphonic acid (MSA) movement. The precipitation at these sites (up to 35 km apart) is influenced by the same air masses, the principal difference being the accumulation rate. At the low-accumulation-rate W20k site (0.17 in ice equivalent), MSA was completely relocated from the summer to winter layer. Moderate movement was observed at the intermediate-accumulation-rate site (0.7 in ice equivalent), Dome Summit South (DSS), while there was no evidence of movement at the high-accumulation-rate DE08 site (1.4 in ice equivalent). The main …


Preliminary Results From The Chemical Records Of An 80.4 M Ice Core Recovered From East Rongbuk Glacier, Qomolangma (Mount Everest), Himalaya, Qin Dahe, Hou Shugui, Zhang Dongqi, Ren Jiawen, Shichang Kang, Paul Andrew Mayewski, Cameron P. Wake Jan 2002

Preliminary Results From The Chemical Records Of An 80.4 M Ice Core Recovered From East Rongbuk Glacier, Qomolangma (Mount Everest), Himalaya, Qin Dahe, Hou Shugui, Zhang Dongqi, Ren Jiawen, Shichang Kang, Paul Andrew Mayewski, Cameron P. Wake

Earth Science Faculty Scholarship

High-resolution chemical records from an 80.4 m ice core from the central Himalaya demonstrate climatic and environmental changes since 1844. The chronological net accumulation series shows a sharp decrease from the mid-1950s, which is coincident with the widely observed glacier retreat. A negative correlation is found between the ice-core delta(18)O record and the monsoon precipitation for Indian region 7. The temporal variation of the terrestrial ions (Ca2+ and Mg2+) is controlled by both the monsoon precipitation for Indian regions 3,7 and 8, located directly south and west of the Himalaya, and the dust-storm duration and frequency in the northern arid …


The Effects Of Flowline Length Evolution On Chemistry-Delta O-18 Profiles From Penny Ice Cap, Baffin Island, Canada, David A. Fisher, Roy M. Koerner, Gregory A. Zielinski, Cameron P. Wake, Christian M. Zdanowicz, Jocelyne C. Bourgeois, Paul Andrew Mayewski, Nancy Grummet Jan 2002

The Effects Of Flowline Length Evolution On Chemistry-Delta O-18 Profiles From Penny Ice Cap, Baffin Island, Canada, David A. Fisher, Roy M. Koerner, Gregory A. Zielinski, Cameron P. Wake, Christian M. Zdanowicz, Jocelyne C. Bourgeois, Paul Andrew Mayewski, Nancy Grummet

Earth Science Faculty Scholarship

The isotopic and chemical signatures for ice-age and Holocene ice from Summit, Greenland and Penny Ice Cap, Baffin Island, Canada, arc compared. The usual pattern of low delta(18)O, high Ca2+ and high Cl- is presented in the Summit records, but Penny Ice Cap has lower than present Cl- in its ice-age ice. A simple extension of the Hansson model (Hansson, 1994) is developed and used to simulate these signatures. The low ice-age Cl- from Penny Ice Cap is explained by having the ice-age ice originating many thousands of km inland near the centre of the Laurentide ice sheet and much …


The Polar Expression Of Enso And Sea-Ice Variability As Recorded In A South Pole Ice Core, Eric A. Myerson, Paul Andrew Mayewski, Karl J. Kreutz, L. David Meeker, Sallie I. Whitlow, Mark S. Twickler Jan 2002

The Polar Expression Of Enso And Sea-Ice Variability As Recorded In A South Pole Ice Core, Eric A. Myerson, Paul Andrew Mayewski, Karl J. Kreutz, L. David Meeker, Sallie I. Whitlow, Mark S. Twickler

Earth Science Faculty Scholarship

An annually dated ice core recovered from South Pole (2850 in a.s.l.) in 1995, that covers the period 1487-1992, was analyzed for the marine biogenic sulfur species methanesulfonate (MS). Empirical orthogonal function analysis is used to calibrate the high-resolution MS series with associated environmental series for the period of overlap (1973-92). Utilizing this calibration we present a similar to500 year long proxy record of the polar expression of the El Nino-Southern Oscillation (ENSO) and southeastern Pacific sea-ice extent variations. These records reveal short-term periods of increased (1800-50, 1900-40) and decreased sea-ice extent (1550-1610., 1660-1710, 1760-1800). In general, increased (decreased) sea-ice …


Chemical Composition Of Fresh Snow On Xixabangma Peak, Central Himalaya, During The Summer Monsoon Season, Shichang Kang, Qin Dahe, Paul Andrew Mayewski, Sharon B. Sneed, Yao Tandong Jan 2002

Chemical Composition Of Fresh Snow On Xixabangma Peak, Central Himalaya, During The Summer Monsoon Season, Shichang Kang, Qin Dahe, Paul Andrew Mayewski, Sharon B. Sneed, Yao Tandong

Earth Science Faculty Scholarship

No abstract provided.


Outlining Proofs In Calculus, Andrew Wohlgemuth Jan 2002

Outlining Proofs In Calculus, Andrew Wohlgemuth

Mathematics and Statistics Faculty Scholarship

Consider a point p and a line l in some plane, with p not on l: How many lines are there in the plane that pass through point p and that are parallel to line l? It seems clear, by what we mean by “point”, “line”, and “plane”, that there is just one such line. This assertion is logically equivalent to Euclid's 5th, or parallel, postulate (in the context of his other postulates).

In fact, this was seen as so obvious by everyone, mathematicians included, that for two thousand years mathematicians attempted to prove it. After all, if it was …


Chemical Composition Of Fresh Snow On Xixabangma Peak, Central Himalaya, During The Summer Monsoon Season, Shichang Kang, Dahe Qin, Paul Andrew Mayewski, Sharon B. Sneed Jan 2002

Chemical Composition Of Fresh Snow On Xixabangma Peak, Central Himalaya, During The Summer Monsoon Season, Shichang Kang, Dahe Qin, Paul Andrew Mayewski, Sharon B. Sneed

Earth Science Faculty Scholarship

The physical and chemical analysis of ice cores recovered from glaciers in the Himalaya provide some of the best records of past climate change in the region (e.g. Qin and others, 2000; Thompson and others, 2000; Kang and others, 2001, 2002). In order to better understand the climatic and environmental records preserved in snow and ice, studies have investigated the precipitation chemistry in the high Himalaya, notably that the northern slopes of the central Himalaya (Mayewski and others, 1986; Jenkins and others 1987) and the southern slopes of the central Himalaya (Shrestha and others, 1997; Marinoni and others, 2001).


Potential Effects Of Oil And Gas Development On Mule Deer And Pronghorn Populations In Western Wyoming, Hall Sawyer, Fred Lindzey, Doug Mcwhirter, Keith Andrews Jan 2002

Potential Effects Of Oil And Gas Development On Mule Deer And Pronghorn Populations In Western Wyoming, Hall Sawyer, Fred Lindzey, Doug Mcwhirter, Keith Andrews

United States Bureau of Land Management: Staff Publications

Western Wyoming is home to the largest, most diverse ungulate populations in the Rocky Mountain region. Maintenance of these populations and protection of their habitats is a primary concern among public and private sectors. While urban expansion, habitat loss, disease and changes in vegetation contribute to management concerns, extensive energy development is thought to pose the most serious threat to mule deer and pronghorn populations. Southwestern Wyoming is rich with oil and gas resources and has consistently produced 10 million barrels of oil each year, with gas production increasing steadily since the early 1980s. A five-county area (Sweetwater, Carbon, Sublette, …


The Administration's Approach To The Esa: Building A Stewardship Ethic For The 21st Century, Amy Klee Jan 2002

The Administration's Approach To The Esa: Building A Stewardship Ethic For The 21st Century, Amy Klee

United States Bureau of Land Management: Staff Publications

When President Nixon signed the Endangered Species Act (ESA) into law in 1973, it is unlikely that anyone imagined the pivotal role it would play in a wide range of land and water management decisions. There are now over 1,200 species of plants and animals listed as threatened or endangered in the United States. Certain areas of the country that historically have had a great diversity of species are now home to large numbers oflisted plants and animals. California, for example, has 292 listed species, and Alabama has 125. In some areas, every major land and water management decision or …


Mammals Of The Grand Staircase-Escalante National Monument: A Literature And Museum Survey, Jerran T. Flinders, Duke S. Rogers, Jackee L. Webber-Alston, Harry A. Barber Jan 2002

Mammals Of The Grand Staircase-Escalante National Monument: A Literature And Museum Survey, Jerran T. Flinders, Duke S. Rogers, Jackee L. Webber-Alston, Harry A. Barber

United States Bureau of Land Management: Staff Publications

This is the first treatment of the mammals of the Grand Staircase-Escalante National Monument (GSENM). GSENM was established in 1996 as a 1.7-million-acre (680,000-ha) federal land reserve under the jurisdiction of the Bureau of Land Management (BLM). To successfully manage this new monument, the BLM is presently developing a management action plan. To provide information for the proper management of mammal species of the area, we have reviewed background literature for each mammal potentially found within the Monument boundaries. We propose that a core area, surrounded by a buffer matrix, be used in GSENM and surrounding public lands to preserve …


Groundwater Quality In Kentucky: Arsenic, R. Stephen Fisher Jan 2002

Groundwater Quality In Kentucky: Arsenic, R. Stephen Fisher

Information Circular--KGS

Arsenic is a naturally occurring element found in low concentrations in rocks, soils, water, plants, and animals (Nriagu, 1994 a, b). In Kentucky, arsenic is commonly found in iron sulfide minerals associated with coal deposits and black shales. Arsenic is released when iron sulfides oxidize during weathering. Once released, it is readily sorbed onto iron oxides and iron oxyhydroxides, which limits arsenic concentrations in the near-surface environment.


Kentucky Is Karst Country! What You Should Know About Sinkholes And Springs, James C. Currens Jan 2002

Kentucky Is Karst Country! What You Should Know About Sinkholes And Springs, James C. Currens

Information Circular--KGS

Kentucky is one of the most famous karst areas in the world. What is karst? It's a landscape with sinkholes, sinking streams, caves, and springs. Much of Kentucky's beautiful scenery, particularly in the Inner Bluegrass Region, is the result of the development of karst landscape. A large amount of Kentucky's prime farmland (including its famous horse farms) is underlain by karst, and springs and wells in karst areas supply water to thousands of homes. Many of Kentucky's major cities, including Frankfort, Louisville, Lexington, Lawrenceburg, Georgetown, Winchester, Paris, Versailles, Nicholasville, Fort Knox, Bowling Green, Elizabethtown, Munfordville, Russellville, Hopkinsville, …


Groundwater Quality In Kentucky: Ph, R. Stephen Fisher Jan 2002

Groundwater Quality In Kentucky: Ph, R. Stephen Fisher

Information Circular--KGS

The parameter pH (the negative base-10 logarithm of hydrogen ion activity, measured in moles per liter) indicates whether a substance will behave as an acid or base. It is one of the most important parameters that describe groundwater quality, because pH largely controls the amount and chemical form of many organic and inorganic solutes in groundwater.