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Articles 10711 - 10740 of 12002

Full-Text Articles in Physical Sciences and Mathematics

The Distribution Of Silicate Strength In Spitzer Spectra Of Agns And Ulirgs, Lei Hao, D. W. Weedman, H. Spoon, J. A. Marshall, N. A. Levenson, Moshe Elitzur, J. R. Houck Feb 2007

The Distribution Of Silicate Strength In Spitzer Spectra Of Agns And Ulirgs, Lei Hao, D. W. Weedman, H. Spoon, J. A. Marshall, N. A. Levenson, Moshe Elitzur, J. R. Houck

Physics and Astronomy Faculty Publications

A sample of 196 AGNs and ULIRGs observed by the Infrared Spectrograph (IRS) on Spitzer is analyzed to study the distribution of the strength of the 9.7 μm silicate feature. Average spectra are derived for quasars, Seyfert 1 and Seyfert 2 AGNs, and ULIRGs. We find that quasars are characterized by silicate features in emission and Seyfert 1s equally by emission or weak absorption. Seyfert 2s are dominated by weak silicate absorption, and ULIRGs are characterized by strong silicate absorption (mean apparent optical depth about 1.5). Luminosity distributions show that luminosities at rest frame 5.5 μm are similar …


The Structure Of The Homunculus. Ii. Modeling The Physical Conditions In Η Carinae's Molecular Shell, Nathan Smith, Gary J. Ferland Feb 2007

The Structure Of The Homunculus. Ii. Modeling The Physical Conditions In Η Carinae's Molecular Shell, Nathan Smith, Gary J. Ferland

Physics and Astronomy Faculty Publications

We present models that reproduce the observed double-shell structure of the Homunculus Nebula around η Carinae, including the stratification of infrared H2 and [Fe II] emission seen in data obtained with the Phoenix spectrograph on Gemini South, as well as the corresponding stratified grain temperature seen in thermal-infrared data. Tuning the model to match the observed shell thickness allows us to determine the threshold density that permits survival of H2. An average density of nH~=(0.5-1)×107 cm-3 in the outer zone is required to allow H2 to exist at all latitudes in the …


Catalytic Cleavage Of Phosphate Ester Bonds By Boron Chelates, David A. Atwood Jan 2007

Catalytic Cleavage Of Phosphate Ester Bonds By Boron Chelates, David A. Atwood

Chemistry Faculty Patents

Novel chemical compounds are disclosed having the general formula L{YXm}n, wherein X is selected from the Group 13 elements, Y is a halide, and L is a chelating ligand containing at least one binding atom contacting the Group 13 element, the atom being selected from the group consisting of C, N, O, and S, and m and n are integers having a value of at least 1. L may be a Schiff base type ligand, such as a salen ligand. The compositions of the present invention may be bidentate, quadridentate, or greater. The compositions may be …


Nitroreductase: Evidence For A Fluxional Low-Temperature State And Its Possible Role In Enzyme Activity, Peng Zhang Jan 2007

Nitroreductase: Evidence For A Fluxional Low-Temperature State And Its Possible Role In Enzyme Activity, Peng Zhang

University of Kentucky Doctoral Dissertations

The enzyme nitroreductase (NR) catalyzes two-electron reduction of high explosives such as trinitrotoluene (TNT), a wide variety of other toxic nitroaromatic compounds, as well as riboflavin derivatives, using a tightly-bound flavin mononucleotide (FMN) cofactor. It has important environmental and clinical implications. Previous studies have focused on elucidating NRs catalytic mechanism and solving its crystal structure.

In this dissertation work, we first develop and implement new strategies for labeling NR with stable isotopes, and report a completely re-designed protocol for NRs purification. Then we report the successful assignment of over half of NRs backbone resonances using 3d-NMR methods. The most significant …


Interactions Between Structures In The Appalachian And Ouachita Foreland Beneath The Gulf Coastal Plain, Donald Matthew Surles Jan 2007

Interactions Between Structures In The Appalachian And Ouachita Foreland Beneath The Gulf Coastal Plain, Donald Matthew Surles

University of Kentucky Doctoral Dissertations

In Alabama, the Paleozoic Appalachian thrust belt plunges southwest beneath the Mesozoic-Cenozoic Gulf Coastal Plain. In Arkansas, the Paleozoic Ouachita thrust belt plunges southeast beneath the Coastal Plain. The strikes of the exposed thrust belts suggest an intersection beneath the Coastal Plain. Well data and seismic reflection profiles confirm the strike and intersection of the thrust belts, and provide information to determine the structure and general stratigraphy of each thrust belt. In east-central Mississippi, the Appalachian thrust belt curves from the regional northeast trace to westward at the intersection with the southeastern terminus of the Ouachita thrust belt, to northwest …


Deep Mid-Infrared Silicate Absorption As A Diagnostic Of Obscuring Geometry Toward Galactic Nuclei, N. A. Levenson, M. M. Sirocky, L. Hao, H. W. W. Spoon, J. A. Marshall, Moshe Elitzur, J. R. Houck Jan 2007

Deep Mid-Infrared Silicate Absorption As A Diagnostic Of Obscuring Geometry Toward Galactic Nuclei, N. A. Levenson, M. M. Sirocky, L. Hao, H. W. W. Spoon, J. A. Marshall, Moshe Elitzur, J. R. Houck

Physics and Astronomy Faculty Publications

The silicate cross section peak near 10 μm produces emission and absorption features in the spectra of dusty galactic nuclei observed with the Spitzer Space Telescope. Especially in ultraluminous infrared galaxies, the observed absorption feature can be extremely deep, as IRAS 08572+3915 illustrates. A foreground screen of obscuration cannot reproduce this observed feature, even at a large optical depth. Instead, the deep absorption requires a nuclear source to be deeply embedded in a smooth distribution of material that is both geometrically and optically thick. In contrast, a clumpy medium can produce only shallow absorption or emission, which are …


Mid-Infrared Galaxy Classification Based On Silicate Obscuration And Pah Equivalent Width, H. W. W. Spoon, J. A. Marshall, J. R. Houck, Moshe Elitzur, L. Hao, L. Armus, B. R. Brandl, V. Charmandaris Jan 2007

Mid-Infrared Galaxy Classification Based On Silicate Obscuration And Pah Equivalent Width, H. W. W. Spoon, J. A. Marshall, J. R. Houck, Moshe Elitzur, L. Hao, L. Armus, B. R. Brandl, V. Charmandaris

Physics and Astronomy Faculty Publications

We present a new diagnostic diagram for mid-infrared spectra of infrared galaxies based on the equivalent width of the 6.2 μm PAH emission feature and the strength of the 9.7 μm silicate feature. Based on the positions in this diagram, we classify galaxies into nine classes ranging from continuum-dominated AGN hot dust spectra and PAH-dominated starburst spectra to absorption-dominated spectra of deeply obscured galactic nuclei. We find that galaxies are systematically distributed along two distinct branches: one of AGN and starburst-dominated spectra and one of deeply obscured nuclei and starburst-dominated spectra. The separation into two branches likely reflects …


Evaluating P And K Fertilizer Prescriptions From Site-Specific Technologies, John H. Grove, E. M. Pena-Yewtukhiw Jan 2007

Evaluating P And K Fertilizer Prescriptions From Site-Specific Technologies, John H. Grove, E. M. Pena-Yewtukhiw

Soil Science News and Views

Developing a field's fertilizer prescription as a part of a site-specific nutrient management plan can be one of the more costly tasks undertaken. Those costs are traditionally associated with gathering of a number of plant and/or soil samples, their testing, as well as acquiring and applying amendments. Soil sample analysis is particularly important for traditional phosphorus (P), potassium (K) and soil acidity (pH) management. Soil sampling requires skill and time, time that may be in short supply when crop harvest is to be soon followed by establishment of a succeeding crop. Soil test results are not always timely, further delaying …


Effect Of Avail® Polymer Applied To Phosphorus Fertilizers On Dry Matter Production And P Uptake Of Fescue At Princeton, Ky, Lloyd W. Murdock, John James Olson, Gene Olson Jan 2007

Effect Of Avail® Polymer Applied To Phosphorus Fertilizers On Dry Matter Production And P Uptake Of Fescue At Princeton, Ky, Lloyd W. Murdock, John James Olson, Gene Olson

Soil Science News and Views

A study was conducted near Princeton, KY to determine if a polymer (AVAIL®) applied to diammonium phosphate (DAP, 18- 46-0) and mono ammonium phosphate (MAP, 11-52-0) would increase (P) phosphorus use efficiency in fescue production on a low P testing soil, when compared to an untreated phosphate fertilizer. AVAIL® (Specialty Fertilizer Products, Belton, MO) is presently being sold in Kentucky as a product to improve phosphorus fertilizer efficiency.


Groundwater Quality In Kentucky: Iron, R. Stephen Fisher, Bart Davidson Jan 2007

Groundwater Quality In Kentucky: Iron, R. Stephen Fisher, Bart Davidson

Information Circular--KGS

Iron is one of the most abundant elements in rocks and soils, and one of the most common problems in groundwater supplies. Rainwater seeping through soils and bedrock dissolves iron and carries it to wells and springs. In deep groundwater systems that lack oxygen, iron occurs as dissolved ferrous ion and the water is clear. Under oxidizing conditions such as in shallow groundwater systems or where the water is exposed to air at a tap or faucet, however, iron converts to a ferric form when it combines with oxygen to form reddish-brown rust particles. In addition to natural sources, elevated …


Groundwater Quality In Kentucky: Manganese, R. Stephen Fisher, Bart Davidson Jan 2007

Groundwater Quality In Kentucky: Manganese, R. Stephen Fisher, Bart Davidson

Information Circular--KGS

Manganese is a common constituent of Kentucky rocks and soils and, along with iron is one of the most widespread causes of problems in groundwater supplies. Rainwater seeping through soils and bedrock dissolves manganese and carries it in the groundwater system to wells and springs. In deep, slow-moving systems that lack oxygen, manganese remains in solution. Under oxidizing conditions, however, such as in shallow groundwater systems or where the water is exposed to air, manganese combines with oxygen to form black particles that can clog plumbing fixtures and stain containers and clothing.


Groundwater Quality In Kentucky: 2,4-D, Bart Davidson, R. Stephen Fisher Jan 2007

Groundwater Quality In Kentucky: 2,4-D, Bart Davidson, R. Stephen Fisher

Information Circular--KGS

2,4-dichlorophenoxyacetic acid, commonly known as 2,4-D, is an herbicide used for selective control of broadleaf and grassy weeds in crops such as corn and wheat, along roadways and rights-of-way, and on pasture and rangeland. 2,4-D is the most widely used herbicide in the world, and the third most widely used in North America after metolachlor and atrazine. 2,4-D is a synthetic, organic, white to yellow, odorless, crystalline powder that dissolves readily in water. It is widely used today primarily because of its low cost.


Groundwater Quality In Kentucky: Atrazine, Bart Davidson, R. Stephen Fisher Jan 2007

Groundwater Quality In Kentucky: Atrazine, Bart Davidson, R. Stephen Fisher

Information Circular--KGS

Atrazine is an organic herbicide used for selective control of broadleaf and grassy weeds in crops such as corn, soybeans, sorghum, sugarcane, macadamia nuts, pineapples, pine trees, grasslands, and roses. Atrazine does not harm the crops, which can absorb and metabolize the herbicide, thereby removing the toxins. It controls targeted plants by inhibiting photosynthesis (Wilkes University Center for Environmental Quality, 2003). Atrazine is a white, odorless, crystalline powder that dissolves readily in water and does not occur naturally. It is widely used because of its low cost and ability to reduce crop losses from weed interference.


Generalized Geologic Map For Land-Use Planning: Green County, Kentucky, Daniel I. Carey, Adam Pike Jan 2007

Generalized Geologic Map For Land-Use Planning: Green County, Kentucky, Daniel I. Carey, Adam Pike

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Martin County, Kentucky, Daniel I. Carey Jan 2007

Generalized Geologic Map For Land-Use Planning: Martin County, Kentucky, Daniel I. Carey

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Morgan County, Kentucky, Daniel I. Carey Jan 2007

Generalized Geologic Map For Land-Use Planning: Morgan County, Kentucky, Daniel I. Carey

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Johnson County, Kentucky, Daniel I. Carey Jan 2007

Generalized Geologic Map For Land-Use Planning: Johnson County, Kentucky, Daniel I. Carey

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Bell County, Kentucky, Daniel I. Carey Jan 2007

Generalized Geologic Map For Land-Use Planning: Bell County, Kentucky, Daniel I. Carey

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Knox County, Kentucky, Daniel I. Carey, John Storm Jan 2007

Generalized Geologic Map For Land-Use Planning: Knox County, Kentucky, Daniel I. Carey, John Storm

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Menifee County, Kentucky, Daniel I. Carey, Peter Eclov Jan 2007

Generalized Geologic Map For Land-Use Planning: Menifee County, Kentucky, Daniel I. Carey, Peter Eclov

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Magoffin County, Kentucky, Daniel I. Carey Jan 2007

Generalized Geologic Map For Land-Use Planning: Magoffin County, Kentucky, Daniel I. Carey

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Breathitt County, Kentucky, Daniel I. Carey, Sally Sloan Jan 2007

Generalized Geologic Map For Land-Use Planning: Breathitt County, Kentucky, Daniel I. Carey, Sally Sloan

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Lee County, Kentucky, Daniel I. Carey, Peter Eclov Jan 2007

Generalized Geologic Map For Land-Use Planning: Lee County, Kentucky, Daniel I. Carey, Peter Eclov

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Bath County, Kentucky, Daniel I. Carey Jan 2007

Generalized Geologic Map For Land-Use Planning: Bath County, Kentucky, Daniel I. Carey

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Floyd County, Kentucky, Daniel I. Carey Jan 2007

Generalized Geologic Map For Land-Use Planning: Floyd County, Kentucky, Daniel I. Carey

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Monroe County, Kentucky, Daniel I. Carey Jan 2007

Generalized Geologic Map For Land-Use Planning: Monroe County, Kentucky, Daniel I. Carey

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Greenup County, Kentucky, Daniel I. Carey Jan 2007

Generalized Geologic Map For Land-Use Planning: Greenup County, Kentucky, Daniel I. Carey

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Generalized Geologic Map For Land-Use Planning: Casey County, Kentucky, Daniel I. Carey, Garland R. Dever Jr. Jan 2007

Generalized Geologic Map For Land-Use Planning: Casey County, Kentucky, Daniel I. Carey, Garland R. Dever Jr.

Map and Chart--KGS

This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.


Oxidative Dna Damage In Mild Cognitive Impairment And Late-Stage Alzheimer's Disease, Mark A. Lovell, William R. Markesbery Jan 2007

Oxidative Dna Damage In Mild Cognitive Impairment And Late-Stage Alzheimer's Disease, Mark A. Lovell, William R. Markesbery

Chemistry Faculty Publications

Increasing evidence supports a role for oxidative DNA damage in aging and several neurodegenerative diseases including Alzheimer's disease (AD). Attack of DNA by reactive oxygen species (ROS), particularly hydroxyl radicals, can lead to strand breaks, DNA–DNA and DNA–protein cross-linking, and formation of at least 20 modified bases adducts. In addition, α,β-unsaturated aldehydic by-products of lipid peroxidation including 4-hydroxynonenal and acrolein can interact with DNA bases leading to the formation of bulky exocyclic adducts. Modification of DNA bases by direct interaction with ROS or aldehydes can lead to mutations and altered protein synthesis. Several studies of DNA base adducts in late-stage …


Groundwater Quality In Watersheds Of The Kentucky River, Salt River, Licking River, Big Sandy River, Little Sandy River, And Tygarts Creek (Kentucky Basin Management Units 1, 2, And 5), R. Stephen Fisher, Bart Davidson, Peter T. Goodmann Jan 2007

Groundwater Quality In Watersheds Of The Kentucky River, Salt River, Licking River, Big Sandy River, Little Sandy River, And Tygarts Creek (Kentucky Basin Management Units 1, 2, And 5), R. Stephen Fisher, Bart Davidson, Peter T. Goodmann

Report of Investigations--KGS

The Kentucky Geological Survey, University of Kentucky, and the Kentucky Division of Water (of the Kentucky Environmental and Public Protection Cabinet) are evaluating groundwater quality throughout the commonwealth to determine regional conditions, assess impacts of nonpoint-source pollutants, establish a basis for detecting changes, and provide essential information for environmental-protection and resource-management decisions.

These evaluations are being conducted in stages. Under the Kentucky Watershed management Framework, Kentucky’s 12 major river basins and tributaries of the Ohio River were grouped into five basin management units (BMU’s). A previous report summarized and evaluated groundwater quality in BMU 3 (watersheds of the Upper Cumberland …