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2000

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Articles 31 - 60 of 277

Full-Text Articles in Life Sciences

A New Fixed-Point Theorem For Logic Programming Semantics, Anthony K. Seda, Pascal Hitzler Jul 2000

A New Fixed-Point Theorem For Logic Programming Semantics, Anthony K. Seda, Pascal Hitzler

Computer Science and Engineering Faculty Publications

We present a new fixed-point theorem akin to the Banach contraction mapping theorem, but in the context of a novel notion of generalized metric space, and show how it can be applied to analyse the denotational semantics of certain logic programs. The theorem is obtained by generalizing a theorem of Priess-Crampe and Ribenboim, which grew out of applications within valuation theory, but is also inspired by a theorem of S.G. Matthews which grew out of applications to conventional programming language semantics. The class of programs to which we apply our theorem was defined previously by us in terms of operators …


The Crest, Summer 2000, Virginia Institute Of Marine Science Jul 2000

The Crest, Summer 2000, Virginia Institute Of Marine Science

Reports

Table of Contents:

  • VIMS Scientists Successfully Spawn Cobia
  • NMFS Faculty Position Established at VIMS
  • Scientists Discover New Species of Perkinsus
  • Researchers Discover New Pollutants Infiltrating Virginia Rivers
  • Sea Scallop Research Resumed in June
  • MARSH Project Will Help Save Tidal Wetlands
  • Virginia's Changing Coastal Community - Indicators of Change
  • New Pound-Net Design Spares Young Fish
  • VIMS Scientist Studies Oysters in India
  • American Shad Focus of Unique Study
  • From the Coleman Bridge to Menai Bridge:
  • VIMS Professor Leads Field-Course in Wales
  • New Experimental Design Course for Teachers
  • Students Teaching Students
  • Horseshoe Crab Research is Timely
  • Award Winning Bridge Website Receives Renewed Funding …


Investigations On The Use Of Ion Mobility Spectrometry For Clinical Chemistry Applications, Henri Parson Patten Jul 2000

Investigations On The Use Of Ion Mobility Spectrometry For Clinical Chemistry Applications, Henri Parson Patten

Theses and Dissertations in Biomedical Sciences

The major objective of this research is to examine ion mobility spectrometry as a rapid screening tool for specific application to clinical chemistry research and laboratory use. Methodology was developed for target analytes representing several classes of physiologically active substances, including anesthetics, illicit drugs, and their metabolites. The IMS characteristics of animal tissues and other compounds such as amino acids and proteins were determined. Quality assurance and control procedures were developed for specific quality data objectives. Criteria were established relating to use of IMS for assessing the precision and accuracy of data, qualitative screening, and semi-quantitative analyses.

It was found …


Effects Of Elevated Atmospheric Co2 On Root Growth, Turnover And Decomposition In A Scrub Oak Ecosystem, John Joseph Dilustro Jul 2000

Effects Of Elevated Atmospheric Co2 On Root Growth, Turnover And Decomposition In A Scrub Oak Ecosystem, John Joseph Dilustro

Biological Sciences Theses & Dissertations

Atmospheric carbon dioxide levels are increasing and predicted to double this century. The implications of this rise on vegetation structure and function are not well understood. Measurement of root growth response to elevated atmospheric carbon dioxide is critical to understanding soil carbon input. I investigated the effects of elevated carbon dioxide on fine root growth and decomposition using open top chambers with both ambient and elevated (700 PPM) CO2 treatments in an oak-palmetto scrub ecosystem at Kennedy Space Center, Florida. Minirhizotron tubes were installed in each elevated and control chamber to allow observation of roots. Each tube was sampled …


Issues Associated With New Developments And Transfers: A West Slope Perspective, Eric Kuhn Jun 2000

Issues Associated With New Developments And Transfers: A West Slope Perspective, Eric Kuhn

Water and Growth in the West (Summer Conference, June 7-9)

8 pages.


Groundwater And Growth Management In The New West: Evolving Law And Practice, A. Dan Tarlock Jun 2000

Groundwater And Growth Management In The New West: Evolving Law And Practice, A. Dan Tarlock

Water and Growth in the West (Summer Conference, June 7-9)

13 pages.


Agenda: Water And Growth In The West, University Of Colorado Boulder. Natural Resources Law Center, The William And Flora Hewlett Foundation Jun 2000

Agenda: Water And Growth In The West, University Of Colorado Boulder. Natural Resources Law Center, The William And Flora Hewlett Foundation

Water and Growth in the West (Summer Conference, June 7-9)

1 v. (various pagings) : ill., maps ; 29 cm. + 1 CD-ROM (4 3/4 in.) + supplement (207 p. ; 29 x 24 cm.)

"Conference co-sponsor The William and Flora Hewlett Foundation."

Conference moderators included University of Colorado School of Law professors Gary C. Bryner, James N. Corbridge, Jr., David H. Getches, Douglas S. Kenney, Kathryn M. Mutz, Peter D. Nichols and Charles F. Wilkinson.

Accompanied by: CD-ROM (4 3/4 in.) and supplement (xiv, 140, [49] p.)

Includes bibliographical references

The event will cover a breadth of issues, including demographics and water-use trends, improved planning and efficient use, implementation …


Key Trends In Population And Land Use In The West, William E. Riebsame Jun 2000

Key Trends In Population And Land Use In The West, William E. Riebsame

Water and Growth in the West (Summer Conference, June 7-9)

9 pages (includes illustrations and maps).

Contains 1 page of references.


Aquaculture Plan For The Recherche Archipelago, Fisheries Western Australia. Jun 2000

Aquaculture Plan For The Recherche Archipelago, Fisheries Western Australia.

Fisheries management papers

Land supply and land cost for aquaculture may become a limiting factor in the foreseeable future. At present, adequate appropriately zoned land is available at reasonable cost. The most prospective land for aquaculture in or near Esperance is where suitable zoned land occurs over saline ground water aquifers or adjacent to the coast. Careful site selection would be necessary to ensure water supply, waste water disposal, services and operational space can be achieved at reasonable cost.


A Quality Future For Recreational Fishing On The West Coast., West Coast Recreational Fishing Working Group Jun 2000

A Quality Future For Recreational Fishing On The West Coast., West Coast Recreational Fishing Working Group

Fisheries management papers

The West Coast Region between Kalbarri and Augusta offers a wide range of recreational fishing opportunities.The West Coast Region also receives more fishing pressure than any other, with an estimated 380 000 anglers fishing each year. Already, the signs of a fishery under pressure are showing. Catch rates of dhufish around inshore reef systems such as the Three-mile are a far cry from the 1950s and 60s when people beachlaunched wooden dinghies to fish the inshore waters for these highly prized fish. Increasing pressure on stocks has led to growing community concerns that the future quality of recreational fishing is …


Pulse And Canola Frost Identification:The Back Pocket Guide, Craig White Jun 2000

Pulse And Canola Frost Identification:The Back Pocket Guide, Craig White

Bulletins 4000 -

This field guide will help you identify the common symptoms of frost damage in pulse and canola crops. It also contains pictures of other plant symptoms often confused with frost damage in these crops.

Frost damage reduces crop yield and grain quality. Early identification of symptoms allows timely crop salvage decisions to be made.

Inspect pulse and canola crops between bud formation and during pod growth if right air temperature (recorded 1.2 m above ground) falls below 2 degrees celsius and there was a frost.

Check low lying, light coloured soil types and known frost prone areas first. Then check …


Table Of Contents Volume 11, Number Three, Summer 2000, Risk Editorial Board Jun 2000

Table Of Contents Volume 11, Number Three, Summer 2000, Risk Editorial Board

RISK: Health, Safety & Environment (1990-2002)

Table of contents for the journal RISK: Health, Safety & Environment (ISSN: 1073-8673)


On-Line Bayesian Speaker Adaptation By Using Tree-Structured Transformation And Robust Priors, Shaojun Wang, Yunxin Zhao Jun 2000

On-Line Bayesian Speaker Adaptation By Using Tree-Structured Transformation And Robust Priors, Shaojun Wang, Yunxin Zhao

Kno.e.sis Publications

This paper presents new results by using our previously proposed on-line Bayesian learning approach for affine transformation parameter estimation in speaker adaptation. The on-line Bayesian learning technique allows updating parameter estimates after each utterance and it can accommodate flexible forms of transformation functions as well as prior probability density functions. We show through experimental results the robustness of heavy tailed priors to mismatch in prior density estimation. We also show that by properly choosing the transformation matrices and depths of hierarchical trees, recognition performance improved significantly.


A Taxonomic Evaluation Of The Comatulid Genus Stephanometra (Echinodermata:Crinoidea), Dana Lin Rankin Jun 2000

A Taxonomic Evaluation Of The Comatulid Genus Stephanometra (Echinodermata:Crinoidea), Dana Lin Rankin

HCNSO Student Theses and Dissertations

Several genera in the comatulid family Mariametridae are currently ambiguously distinguished on the basis of variations in length and robustness of oral pinnules. Previous descriptions have suggested that at least the genera Stephanometra and Lamprometra are imperfectly distinguishable. A detailed re-examination of morphology coupled with principal component analyses of morphometric data and cladistic analyses provide support for a monophyletic Stephanometra distinct from Lamprometra. A preliminary morphological analysis suggests that Dichrometra and Liparometra should be synonymized with Lamprometra. The six currently recognized species of Stephanometra uniquely share at least one pair of oral pinnules characterized by enlarged size, reduced ambulacral groove …


Environmental Guidelines For New And Existing Piggeries, A Latto, John Noonan, R. J. Taylor Jun 2000

Environmental Guidelines For New And Existing Piggeries, A Latto, John Noonan, R. J. Taylor

Bulletins 4000 -

These guidelines apply to the management of Western Australia piggeries in Western Australia, including intensive Growing pigs under intensive conditions where the and extensive operations, straw-based housing and animals spend their entire life cycle indoors, is an combinations of these (otherwise referred to as semi- important part of the Western Australian and intensive housing).


Extralimital Records Of The Mexican Free-Tailed Bat (Tadarida Brasilensis Mexicana) In The Central United States And Their Biological Significance, Hugh H. Genoways, Patricia W. Freeman, Cary Grell May 2000

Extralimital Records Of The Mexican Free-Tailed Bat (Tadarida Brasilensis Mexicana) In The Central United States And Their Biological Significance, Hugh H. Genoways, Patricia W. Freeman, Cary Grell

School of Natural Resources: Faculty Publications

Two new records of Tadarida brasiliensis mexicana are reported from Nebraska. The literature records of this taxon from the central United States are summarized. In this region of North America, these bats occupy a “natal range” where the species carries on regular reproductive activities and the populations are relatively stable, including California, Arizona, New Mexico, Texas, and Oklahoma. To the north of the natal range of T. b. mexicana is a “pioneering zone” where, under favorable conditions, the species is capable of reproducing and conducting its normal activities. The pioneering zone of the Mexican free-tailed bat includes Barber and Comanche …


Shifting Distributional Patterns Of Mammals In Nebraska, Russell A. Benedict, Hugh H. Genoways, Patricia W. Freeman May 2000

Shifting Distributional Patterns Of Mammals In Nebraska, Russell A. Benedict, Hugh H. Genoways, Patricia W. Freeman

School of Natural Resources: Faculty Publications

New distributional records are presented for 20 species of mammals in Nebraska. The majority of these records appear to represent changes in geographic distribution rather than just better sampling in poorly known areas. One group of mammals, including the opossum, northern myotis, evening bat, red bat, woodchuck, white-footed mouse, and gray fox, is expanding westward, probably in response to increasing woodlands along river systems. Another group, including the meadow vole, masked shrew, and least weasel, is expanding southward, possibly in response to new prey species and changing microclimates. The eastern woodrat appears to be expanding northward in eastern Nebraska. The …


The Rural Towns Program : Groundwater Modelling : The Merredin Catchment, J Matta May 2000

The Rural Towns Program : Groundwater Modelling : The Merredin Catchment, J Matta

Resource management technical reports

Agriculture Western Australia (Agwest), as part of the Rural Towns Program, was engaged to test the application of a groundwater model for potential future management options against salinity for the Merredin townsite. This report illustrates some of the options that could be implemented to achieve the objective of salinity management.


Local Properties Of Query Languages, Guozhu Dong, Leonid Libkin, Limsoon Wong May 2000

Local Properties Of Query Languages, Guozhu Dong, Leonid Libkin, Limsoon Wong

Kno.e.sis Publications

In this paper we study the expressiveness of local queries. By locality we mean — informally — that in order to check if a tuple belongs to the result of a query, one only has to look at a certain predetermined portion of the input. Examples include all relational calculus queries. We start by proving a general result describing outputs of local queries. This result leads to many easy inexpressibility proofs for local queries. We then consider a closely related property, namely, the bounded degree property. It describes the outputs of local queries on structures that locally look “simple.” Every …


Studies On The Roles Of Atp In Nitrogenase Catalysis, Wei Wu May 2000

Studies On The Roles Of Atp In Nitrogenase Catalysis, Wei Wu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogenase is the enzyme that catalyzes the reduction of nitrogen to ammonia in a reaction requiring MgATP hydrolysis. Two component proteins of nitrogenase are the iron protein (Fe protein) and the molybdenum-iron protein (MoFe protein).

Nitrogenase contains two nucleotide binding sites. During catalysis, the Fe protein binds two MgATP first. The conformational changes induced upon MgATP binding allow the Fe protein to associate with the MoFe protein. After the formation of the Fe protein-MoFe protein complex, a single electron is transferred from the Fe protein to the MoFe protein, an event that is coupled to MgATP hydrolysis in the Fe …


Responses Of Sphagnum And Carex Peatlands To Ultraviolet-B Radiation, And A Meta-Analysis Of Uv-B Effects On Vascular Plants, Peter S. Searles May 2000

Responses Of Sphagnum And Carex Peatlands To Ultraviolet-B Radiation, And A Meta-Analysis Of Uv-B Effects On Vascular Plants, Peter S. Searles

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The severity of stratospheric ozone depletion in the temperate and polar latitudes has raised concerns about the sensitivity of terrestrial vegetation and ecosystems to solar ultraviolet (UV-B) radiation. This dissertation examined the responses of plants and microbes to solar UV-B for 3 years in Tierra del Fuego, Argentina (55° S). This region is under the influence of the Antarctic "ozone hole" during the austral spring. Additionally, a quantitative review of the UV-B literature was conducted using a set of statistical techniques known as meta-analysis.

For the field studies in Tierra del Fuego, plots were established in a Sphagnum moss peatland …


Herbicide Movement And Dissipation At Four Midwestern Sites, S. A. Clay, R. H. Dowdy, J. A. Lamb, J. L. Anderson, B. Lowery, R. E. Knight, D. E. Clay May 2000

Herbicide Movement And Dissipation At Four Midwestern Sites, S. A. Clay, R. H. Dowdy, J. A. Lamb, J. L. Anderson, B. Lowery, R. E. Knight, D. E. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

This study was conducted to evaluate atrazine (2‐chloro‐4‐ethylamino‐6‐isopropyl‐1, 3, 5‐triazine) and alachlor (2‐chIoro‐N‐(methoxymethyl)acetamide) dissipation and movement to shallow aquifers across the Northern Sand Plains region of the United States. Sites were located at Minnesota on a Zimmerman fine sand, North Dakota on Hecla sandy loam, South Dakota on a Brandt silty clay loam, and Wisconsin on a Sparta sand. Herbicide concentrations were determined in soil samples taken to 90 cm four times during the growing season and water samples taken from the top one m of aquifer at least once every three months. Herbicides were detected to a …


Separation Of Single Gene Effects From Additive-Dominance Genetic Models, Jixiang Wu, Johnie N. Jenkins, Jack Mccarty Jr, Chris Cheatham Apr 2000

Separation Of Single Gene Effects From Additive-Dominance Genetic Models, Jixiang Wu, Johnie N. Jenkins, Jack Mccarty Jr, Chris Cheatham

Conference on Applied Statistics in Agriculture

Separation of single gene and polygenic effects would be useful in crop improvement. In this study, additive-dominance model with a single qualitative gene based on diallel crosses of parents and progeny F1s (or F2s) was examined. The mixed linear model approach, minimum norm quadratic unbiased estimation (MINQUE), was used to estimate the variance and covariance components and single gene effects. Monte Carlo simulation was used to evaluate the efficiency of each parameter estimated from the MINQUE approach for this genetic model. The results of 200 simulations indicated that estimates of variance components and single gene effects …


Performance Of The Exact And Chi-Square Tests On Sparse Contingency Tables, D. G. Renter, J. J. Higgins, J. M. Sargeant Apr 2000

Performance Of The Exact And Chi-Square Tests On Sparse Contingency Tables, D. G. Renter, J. J. Higgins, J. M. Sargeant

Conference on Applied Statistics in Agriculture

A cross-sectional observational study design was used to determine the prevalence of Escherichia coli 0157:H7 in wild deer feces. Samples were voluntarily submitted at a number of different locations. In order to determine if the proportions of E. coli 0157: H7 positive samples submitted were equal for each of the 26 locations, a 26 by 2 contingency table was analyzed. There were only four E. coli 0157:H7 positive samples, which resulted in a sparse table. It is possible to obtain statistically significant results in sparse tables using Fisher's exact test, whereas the chi-square test is generally unreliable in such situations. …


An Autoregression Model For A Paired Watershed Comparison, D. Meek, D. Dinnes, D. Jaynes, C. Cambardella, T. Colvin, J. Hatfield, D. Karlen Apr 2000

An Autoregression Model For A Paired Watershed Comparison, D. Meek, D. Dinnes, D. Jaynes, C. Cambardella, T. Colvin, J. Hatfield, D. Karlen

Conference on Applied Statistics in Agriculture

Analysis of water quality data from a paired watershed design is needed to determine if a best fertilizer management practice reduces a specific water quality variable compared to a conventional fertilizer management practice. This study examines an existing recommended method of analysis for paired watershed designs, simple analysis of covariance (ANCOVA) on time aggregated data, then offers two autoregression analyses (AR) as alternatives. The first approach models the sequence of paired differences and estimates its 95% confidence band. The second approach develops individual watershed AR models then examines the joint 95% confidence interval about the predicted difference. A reliability analysis …


Optimum Design For Exponential Model Using An Exponential Loss Function And Its Applications In Agriculture, Imad H. Khamis Apr 2000

Optimum Design For Exponential Model Using An Exponential Loss Function And Its Applications In Agriculture, Imad H. Khamis

Conference on Applied Statistics in Agriculture

Accelerated life testing has been used for years in engineering. Test units are run at high stress and fail sooner than at design stress. The lifetime at design stress is estimated by extrapolation using a regression model. This paper considers the optimum design of accelerated life tests in which two levels of stresses, high and low are constantly applied. For the exponential model the expected value of an exponential loss function of the arameter is to be used. The initial sample proportion allocated to the high stress which minimizes the expected loss function is determined. In the agriculture context, plants …


Uncertainty Analysis Of A Pipe Model Based On Correlated Distributions, Shoufan Fang, George Z. Gertner Apr 2000

Uncertainty Analysis Of A Pipe Model Based On Correlated Distributions, Shoufan Fang, George Z. Gertner

Conference on Applied Statistics in Agriculture

Traditionally, uncertainty analysis of complex simulation models has been conducted based on the assumption of that the components of the model are independent. In practice, correlation is universal in ecosystems. This study applied Bayesian estimation and rejection sampling to generate correlated random samples for an uncertainty analysis of a process based forest growth model, a pipe model. Comparison of error budgets built using independent and correlated distributions shows that correlated distributions are very important to provide reasonable and realistic simulation and uncertainty analysis.


A Simulation Study To Evaluate Proc Mixed Analysis Of Repeated Measures Data, Leanna Guerin, Walter W. Stroup Apr 2000

A Simulation Study To Evaluate Proc Mixed Analysis Of Repeated Measures Data, Leanna Guerin, Walter W. Stroup

Conference on Applied Statistics in Agriculture

Experiments with repeated measurements are common in pharmaceutical trials, agricultural research, and other biological disciplines. Many aspects of the analysis of such experiments remain controversial. With increasingly sophisticated software becoming available, e.g. PROC MIXED, data analysts have more options from which to choose, and hence more questions about the value and impact of these options. These dilemmas include the following. MIXED offers a number of different correlated error models and several criteria for choosing among competing models. How do the model selection criteria behave? How is inference affected if the correlated error model is misspecified? Some texts use random between …


Some Strategies For Selecting And Fitting Covariance Structures For Repeated Measures, Raul E. Macchiavelli Apr 2000

Some Strategies For Selecting And Fitting Covariance Structures For Repeated Measures, Raul E. Macchiavelli

Conference on Applied Statistics in Agriculture

Since in longitudinal studies the covariance structure is often regarded as a nuisance parameter, the strategy has been to use a parsimonious covariance model that describes adequately the observed data and permits better inference on the parameters of interest. In this paper we present some diagnostic tools to choose an appropriate covariance structure and discuss some strategies for fitting it. The main diagnostic tool is the "residual", computed as the standardized difference between the elements of the fitted covariance (concentration or correlation) matrix and the corresponding unstructured matrix. SAS Proc Calis is a very efficient procedure that fits many covariance …


Bias In Principal Components Analysis Due To Correlated Observations, Hong Jiang, Kent M. Eskridge Apr 2000

Bias In Principal Components Analysis Due To Correlated Observations, Hong Jiang, Kent M. Eskridge

Conference on Applied Statistics in Agriculture

A common practice in many scientific disciplines is to take measurements on several different variables on each unit from a designed experiment. This practice is cost efficient and results in data that may be analyzed using multivariate statistical methods. Usually, principal components analysis (PCA) is conducted by decomposing the covariance matrix of the several dependent variables using eigenanalysis without accounting for possible correlations among the observations. To evaluate how correlated observations bias PCA results, we used algebraic derivation and simulation for several different types of correlation structures. Our results indicated that sampling error generally had a much larger impact on …