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Articles 1 - 21 of 21

Full-Text Articles in Physical Sciences and Mathematics

Diatoms In Hyporheic Sediments Trace Organic Matter Retention And Processing In The Mcmurdo Dry Valleys, Antarctica, Anna J. Bergstrom Feb 2021

Diatoms In Hyporheic Sediments Trace Organic Matter Retention And Processing In The Mcmurdo Dry Valleys, Antarctica, Anna J. Bergstrom

Geosciences Faculty Publications and Presentations

In low‐nutrient streams in cold and arid ecosystems, the spiraling of autochthonous particulate organic matter (POM) may provide important nutrient subsidies downstream. Because of its lability and the spatial heterogeneity of processing in hyporheic sediments, the downstream transport and fate of autochthonous POM can be difficult to trace. In Antarctic McMurdo Dry Valley (MDV) streams, any POM retained in the hyporheic zone is expected to be derived from surface microbial mats that contain diatoms with long‐lasting silica frustules. We tested whether diatom frustules can be used to trace the retention of autochthonous POM in the hyporheic zone and whether certain …


Strategies To Manage Cloud Computing Operational Costs, Frankie Nii A Sackey Jan 2018

Strategies To Manage Cloud Computing Operational Costs, Frankie Nii A Sackey

Walden Dissertations and Doctoral Studies

Information technology (IT) managers worldwide have adopted cloud computing because of its potential to improve reliability, scalability, security, business agility, and cost savings; however, the rapid adoption of cloud computing has created challenges for IT managers, who have reported an estimated 30% wastage of cloud resources. The purpose of this single case study was to explore successful strategies and processes for managing infrastructure operations costs in cloud computing. The sociotechnical systems (STS) approach was the conceptual framework for the study. Semistructured interviews were conducted with 6 IT managers directly involved in cloud cost management. The data were analyzed using a …


Agenda: Innovations In Managing Western Water: New Approaches For Balancing Environmental, Social, And Economic Outcomes, University Of Colorado Boulder. Getches-Wilkinson Center For Natural Resources, Energy, And The Environment Jun 2015

Agenda: Innovations In Managing Western Water: New Approaches For Balancing Environmental, Social, And Economic Outcomes, University Of Colorado Boulder. Getches-Wilkinson Center For Natural Resources, Energy, And The Environment

Innovations in Managing Western Water: New Approaches for Balancing Environmental, Social and Economic Outcomes (Martz Summer Conference, June 11-12)

Many aspects of western water allocation and management are the product of independent and uncoordinated actions, several occurring a century or more ago. However, in this modern era of water scarcity, it is increasingly acknowledged that more coordinated and deliberate decision-making is necessary for effectively balancing environmental, social, and economic objectives. In recent years, a variety of forums, processes, and tools have emerged to better manage the connections between regions, sectors, and publics linked by shared water systems. In this event, we explore the cutting edge efforts, the latest points of contention, and the opportunities for further progress.


Chemical Processes Governing The Equilibrium Between Organic And Inorganic Carbon: Probing The Mechanisms Of Iron Catalyzed Reactive Oxygen Species Production, Joy Kelechi Ihekweazu Jan 2015

Chemical Processes Governing The Equilibrium Between Organic And Inorganic Carbon: Probing The Mechanisms Of Iron Catalyzed Reactive Oxygen Species Production, Joy Kelechi Ihekweazu

Theses and Dissertations

This study examines the oxidation of organic carbon that occurs concurrently with the autoxidation of Fe(II) to determine the role that geochemical constituents have on both the autoxidation of Fe(II) and subsequent ROS production. The reaction between reduced carbon and oxygen is thermodynamically favorable, but kinetically proceeds slowly. Fe(II) facilitates the equilibration of reduced carbon and oxygen. This equilibration occurs naturally in saline estuaries, where oxygen rich seawater mixes with anoxic groundwater. We characterized a saline estuary at the Baruch Institute and used those characterizations to recreate natural water conditions in the lab. Using simulated natural water we then examined …


Interaction Between The Broad-Lined Type Ic Supernova 2012ap And Carriers Of Diffuse Interstellar Bands, Dan Milisavljevic, Raffaella Margutti, Kyle N. Crabtree, Jonathan B. Foster, Alicia M. Soderberg, Robert A. Fesen, Jerod T. Parrent Feb 2014

Interaction Between The Broad-Lined Type Ic Supernova 2012ap And Carriers Of Diffuse Interstellar Bands, Dan Milisavljevic, Raffaella Margutti, Kyle N. Crabtree, Jonathan B. Foster, Alicia M. Soderberg, Robert A. Fesen, Jerod T. Parrent

Dartmouth Scholarship

Diffuse interstellar bands (DIBs) are absorption features observed in optical and near-infrared spectra that are thought to be associated with carbon-rich polyatomic molecules in interstellar gas. However, because the central wavelengths of these bands do not correspond to electronic transitions of any known atomic or molecular species, their nature has remained uncertain since their discovery almost a century ago. Here we report on unusually strong DIBs in optical spectra of the broad-lined Type Ic supernova SN 2012ap that exhibit changes in equivalent width over short ( 30 days) timescales. The 4428 Å and 6283 Å DIB features get weaker with …


Fast, Resolution-Consistent Spatial Prediction Of Global Processes From Satellite Data, Hsin-Cheng Huang, Noel A. Cressie, John Gabrosek Feb 2013

Fast, Resolution-Consistent Spatial Prediction Of Global Processes From Satellite Data, Hsin-Cheng Huang, Noel A. Cressie, John Gabrosek

Professor Noel Cressie

Polar orbiting satellites remotely sense the earth and its atmosphere, producing datasets that give daily global coverage. For any given day, the data are many and measured at spatially irregular locations. Our goal in this article is to predict values that are spatially regular at different resolutions; such values are often used as input to general circulation models (GCMs) and the like. Not only do we wish to predict optimally, but because data acquisition is relentless, our algorithm must also process the data very rapidly. This article applies a multiresolution autoregressive tree-structured model, and presents a new statistical prediction methodology …


Accordion Vs. Quantum Tectonics: Insights Into Continental Growth Processes From The Paleozoic Of Eastern Gondwanan, Jonathan C. Aitchison, Solomon Buckman Sep 2012

Accordion Vs. Quantum Tectonics: Insights Into Continental Growth Processes From The Paleozoic Of Eastern Gondwanan, Jonathan C. Aitchison, Solomon Buckman

Solomon Buckman Dr.

The Early Paleozoic Lachlan Fold Belt of eastern Australia is widely regarded as an ancient convergent plate margin beneath which paleo-Pacific (Panthalassic) oceanic lithosphere was continuously subducted. It is cited as the type example of a retreating accretionary orogeny. However, sandstone compositions, the sedimentological nature and timing of chert accumulation and overall stratigraphic architecture are not necessarily consistent with this model. We suggest an alternative explanation for growth of Gondwanan continental margin. Oceanic lithosphere outboard of the passive Gondwana continental margin was subducted beneath an extensive intra-oceanic island arc that now crops out as an allochthonous element (Macquarie arc) within …


Accordion Vs. Quantum Tectonics: Insights Into Continental Growth Processes From The Paleozoic Of Eastern Gondwanan, Jonathan C. Aitchison, Solomon Buckman Jan 2012

Accordion Vs. Quantum Tectonics: Insights Into Continental Growth Processes From The Paleozoic Of Eastern Gondwanan, Jonathan C. Aitchison, Solomon Buckman

Faculty of Science - Papers (Archive)

The Early Paleozoic Lachlan Fold Belt of eastern Australia is widely regarded as an ancient convergent plate margin beneath which paleo-Pacific (Panthalassic) oceanic lithosphere was continuously subducted. It is cited as the type example of a retreating accretionary orogeny. However, sandstone compositions, the sedimentological nature and timing of chert accumulation and overall stratigraphic architecture are not necessarily consistent with this model. We suggest an alternative explanation for growth of Gondwanan continental margin. Oceanic lithosphere outboard of the passive Gondwana continental margin was subducted beneath an extensive intra-oceanic island arc that now crops out as an allochthonous element (Macquarie arc) within …


Model For Amorphous Aggregation Processes, Samual Stranks, Heath Ecroyd, Steve Van Sluyter, Elizabeth J. Waters, John A. Carver, Lorenz Von Smekal Dec 2011

Model For Amorphous Aggregation Processes, Samual Stranks, Heath Ecroyd, Steve Van Sluyter, Elizabeth J. Waters, John A. Carver, Lorenz Von Smekal

Heath Ecroyd

The amorphous aggregation of proteins is associated with many phenomena, ranging from the formation of protein wine haze to the development of cataract in the eye lens and the precipitation of recombinant proteins during their expression and purification. While much literature exists describing models for linear protein aggregation, such as amyloid fibril formation, there are few reports of models which address amorphous aggregation. Here, we propose a model to describe the amorphous aggregation of proteins which is also more widely applicable to other situations where a similar process occurs, such as in the formation of colloids and nanoclusters. As first …


Minerogenetic Mechanisms Occurring In The Cave Environment: An Overview, Bogdan P. Onac, Paolo Forti Jan 2011

Minerogenetic Mechanisms Occurring In The Cave Environment: An Overview, Bogdan P. Onac, Paolo Forti

International Journal of Speleology

Perhaps man’s first motivation to explore caves, beyond using them as shelter, was the search for substances that were not available elsewhere: most of them were minerals. However, for a long time it was believed that the cave environment was not very interesting from the mineralogical point of view. This was due to the fact that most cave deposits are normally composed of a single compound: calcium carbonate. Therefore, the systematic study of cave mineralogy is of only recent origin. However, although only a limited number of natural cavities have been investigated in detail, about 350 cave minerals have already …


Does Co-Opetition Change The Game? A Bayesian Analysis Of Participation Strategy In An Industry Standard-Setting Organization, Robert J. Kauffman, Benjamin B. M. Shao, Juliana Y. Tsai Jan 2010

Does Co-Opetition Change The Game? A Bayesian Analysis Of Participation Strategy In An Industry Standard-Setting Organization, Robert J. Kauffman, Benjamin B. M. Shao, Juliana Y. Tsai

Research Collection School Of Computing and Information Systems

Across different industries, we observe the emergence of industry standard-setting organizations (SSO) that focus on the creation of industry-specific process standards. Firms adopt a strategy of co-opetition, the combination of cooperation and competition, during standards development. We propose that a firm's co-opetition strategy is revealed to some extent by when it elects to participate in an industry SSO. Bayesian information updating offers an effective empirical modeling perspective for studying firms' participation strategies when managers' beliefs and uncertainties are factored into their decision-making. We analyze a panel data set of 73 U.S. public firms over a 20-year period. These firms are …


Model For Amorphous Aggregation Processes, Samual Stranks, Heath Ecroyd, Steve Van Sluyter, Elizabeth J. Waters, John A. Carver, Lorenz Von Smekal Jan 2009

Model For Amorphous Aggregation Processes, Samual Stranks, Heath Ecroyd, Steve Van Sluyter, Elizabeth J. Waters, John A. Carver, Lorenz Von Smekal

Faculty of Science - Papers (Archive)

The amorphous aggregation of proteins is associated with many phenomena, ranging from the formation of protein wine haze to the development of cataract in the eye lens and the precipitation of recombinant proteins during their expression and purification. While much literature exists describing models for linear protein aggregation, such as amyloid fibril formation, there are few reports of models which address amorphous aggregation. Here, we propose a model to describe the amorphous aggregation of proteins which is also more widely applicable to other situations where a similar process occurs, such as in the formation of colloids and nanoclusters. As first …


Fast, Resolution-Consistent Spatial Prediction Of Global Processes From Satellite Data, Hsin-Cheng Huang, Noel A. Cressie, John Gabrosek Jan 2002

Fast, Resolution-Consistent Spatial Prediction Of Global Processes From Satellite Data, Hsin-Cheng Huang, Noel A. Cressie, John Gabrosek

Faculty of Informatics - Papers (Archive)

Polar orbiting satellites remotely sense the earth and its atmosphere, producing datasets that give daily global coverage. For any given day, the data are many and measured at spatially irregular locations. Our goal in this article is to predict values that are spatially regular at different resolutions; such values are often used as input to general circulation models (GCMs) and the like. Not only do we wish to predict optimally, but because data acquisition is relentless, our algorithm must also process the data very rapidly. This article applies a multiresolution autoregressive tree-structured model, and presents a new statistical prediction methodology …


Filter Strip Performance And Processes For Different Vegetation, Widths, And Contaminants, T. J. Schmitt, M. G. Dosskey, K. D. Hoagland Jan 1999

Filter Strip Performance And Processes For Different Vegetation, Widths, And Contaminants, T. J. Schmitt, M. G. Dosskey, K. D. Hoagland

School of Natural Resources: Faculty Publications

Filter strips are widely prescribed to reduce contaminants in surface runoff from agricultural fields. Tbis study compared performance of different filter strip designs on several contaminants and evaluated the contribnting processes. Different vegetation types and widths were investigated using simulated runoff event on large plots (3 m X 7.5 or 15 m) having fine-textured soil and a 6 to 7% slope. Filter strips 7.5 and 15 m wide downslope greatly reduced concentrations of sediment in runoff (76-93%) and contaminants strongly associated with sediment (total P, 55-79%; permethrin, 27-83% [(3-phenoxyphenyl) methyl (±)-cis, trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane carboxylate ]). They had less effect on concentrations …


Nonequilibrium Processes In Polymers Undergoing Interchange Reactions. Part 2: Reaction-Diffusion Processes, Alejandro Garcia, J. Pojman, D. Kondepudi, C. Van De Broeck Jan 1991

Nonequilibrium Processes In Polymers Undergoing Interchange Reactions. Part 2: Reaction-Diffusion Processes, Alejandro Garcia, J. Pojman, D. Kondepudi, C. Van De Broeck

Faculty Publications

A reactiodffusion system of polymers undergoing interchange reactions is studied. The equation that describes the dynamics of the system is similar to the Boltzmann equation for a gas of hard spheres. We consider a one-dimensionsl system in which the average length and the concentrations at the boundaries are fixed. The resulting steady states are obtained analytically and with numerical integration of equations obtained by using a local equilibrium approximation. Monte Carlo simulations of experimentally realizable conditions were performed and compared. The results reveal a nonlinear distribution of molecular concentration and mass. The entropy of the polymer distributions is calculated as …


Nonequilibrium Processes In Polymers Undergoing Interchange Reactions. Part 2: Reaction-Diffusion Processes, Alejandro Garcia, J. Pojman, D. Kondepudi, C. Van De Broeck Jan 1991

Nonequilibrium Processes In Polymers Undergoing Interchange Reactions. Part 2: Reaction-Diffusion Processes, Alejandro Garcia, J. Pojman, D. Kondepudi, C. Van De Broeck

Alejandro Garcia

A reactiodffusion system of polymers undergoing interchange reactions is studied. The equation that describes the dynamics of the system is similar to the Boltzmann equation for a gas of hard spheres. We consider a one-dimensionsl system in which the average length and the concentrations at the boundaries are fixed. The resulting steady states are obtained analytically and with numerical integration of equations obtained by using a local equilibrium approximation. Monte Carlo simulations of experimentally realizable conditions were performed and compared. The results reveal a nonlinear distribution of molecular concentration and mass. The entropy of the polymer distributions is calculated as …


Large Deviations For Processes With Independent Increments, James Lynch, Jayaram Sethuraman Jan 1987

Large Deviations For Processes With Independent Increments, James Lynch, Jayaram Sethuraman

Faculty Publications

Let X be a topological space and F denote the Borel σ-field in X. A family of probability measures {Pλ} is said to obey the large deviation principle (LDP) with rate function I(⋅) if Pλ(A) can be suitably approximated by exp{−λinfx∈AI(x)} for appropriate sets A in F. Here the LDP is studied for probability measures induced by stochastic processes with stationary and independent increments which have no Gaussian component. It is assumed that the moment generating function of the increments exists and thus the sample paths of such stochastic processes lie in the space of functions of bounded variation. The …


Biogeochemical Processes In Sagebrush Ecosystems: Interactions With Terrain, United States, National Aeronautics And Space Administration Dec 1985

Biogeochemical Processes In Sagebrush Ecosystems: Interactions With Terrain, United States, National Aeronautics And Space Administration

Plants

Field data collection to support analysis of TM data was accomplished from June 22 to August 28th. Color infrared aerial photography acquired by a U2 on June 12, 1985 was used to locate and identify several vegetation communities. Forty sites where the USFS has collected long term ground cover were located in the field, delineated on aerial photos and ground photos of current conditions taken.


Laverkin Springs, Utah On-Site Pretreatment And Desalting Processes Evaluations, R. J. Eisenhauer, Bureau Of Reclamation Apr 1985

Laverkin Springs, Utah On-Site Pretreatment And Desalting Processes Evaluations, R. J. Eisenhauer, Bureau Of Reclamation

All U.S. Government Documents (Utah Regional Depository)

During December 1979 through August 1980, pilot plants and laboratory facilities were operated at the LaVerkin Springs, Utah site to characterize the water and to evaluate various pretreatment processes and desalting processes. The pretreatment processes studied included aeration-precipitation, lime treatment, lime-soda ash treatment, and lime-ion exchange treatment. Desalting at 80 and 90 percent water recovery levels was studied with both electrodialysis and high pressure reverse osmosis process equipment. Also, a "spiractor" was evaluated at the site as a lime-soda ash reactor and as a calcium sulfate desupersaturator. Data and results obtained from the test program will be used for feasibility …


Proper Mixtures Of Ellis County Soils For Adobe Construction, And Their Physical Properties Part Ii, Buster Wayne Read, W. G. Read, H. A. Zinszer Jan 1951

Proper Mixtures Of Ellis County Soils For Adobe Construction, And Their Physical Properties Part Ii, Buster Wayne Read, W. G. Read, H. A. Zinszer

Fort Hays Studies Series

Houses made of soil have been built for centuries, but until recently the trend had been away from soil to some other building material. Now, however, adobe is again beginning to be recognized as a satisfactory, reliable building material for our time.


Proper Mixtures Of Ellis County Soils For Adobe Construction, And Their Physical Properties, Buster Wayne Read, W. G. Read, H. A. Zinszer Jan 1950

Proper Mixtures Of Ellis County Soils For Adobe Construction, And Their Physical Properties, Buster Wayne Read, W. G. Read, H. A. Zinszer

Fort Hays Studies Series

This paper deals with the adobe strategy of construction which is mixing and puddling the materials to be applied to a sun-dried brick or to a structure of that material. The work was divided into three main parts: (1) Survey of Ellis County Soils; (2) Selection of soil material with respect to shrinkage; and (3) Treatment of soils with respect to waterproofing.