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Articles 51991 - 52020 of 59402

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Magnetic Surveys Help Reassess Volcanic Hazards At Yucca Mountain, Nevada, Charles B. Connor, Sammantha Lane-Magsino, John A. Stamatakos, Ronald H. Martin, Peter C. Lafemina, Brittain E. Hill, Steve Lieber Feb 1997

Magnetic Surveys Help Reassess Volcanic Hazards At Yucca Mountain, Nevada, Charles B. Connor, Sammantha Lane-Magsino, John A. Stamatakos, Ronald H. Martin, Peter C. Lafemina, Brittain E. Hill, Steve Lieber

School of Geosciences Faculty and Staff Publications

Natural disasters like volcanic eruptions occur infrequently, but if they occur near nuclear power plants or high‐level radioactive waste repositories, local and global communities can be threatened. Ideally, such facilities should be constructed only where geologic risk is very low.

Estimating the probabilities of such events requires a comprehensive understanding of site geology and the geologic processes operating in the site region on timescales of 104 to 107years. In light of these requirements, geologists and geophysicists must continually improve techniques for site characterization.


New Constraints On Source Processes Of Volcanic Tremor At Arenal Volcano, Costa Rica, Using Broadband Seismic Data, John P. Benoit, Stephen R. Mcnutt Feb 1997

New Constraints On Source Processes Of Volcanic Tremor At Arenal Volcano, Costa Rica, Using Broadband Seismic Data, John P. Benoit, Stephen R. Mcnutt

School of Geosciences Faculty and Staff Publications

Broadband seismic data recorded 2.3 km from the active vent of Arenal Volcano, Costa Rica, provide new constraints on tremor source processes. Arenal's tremor contains as many as seven harmonics, whose frequencies vary temporally by up to 75 percent, from initial values of 1.9 Hz for the first peak immediately following explosive eruptions to 3.2–3.5 Hz several minutes later. We infer that gas bubble concentration is variable within the conduit and also changes as a function of time, thereby changing the acoustic velocity. We infer that the source is a shallow, 200–660 m-long, vertically oriented 1-D resonator with matched boundary …


A Guide To Mechanical Rangeland Regeneration, J. Addison Feb 1997

A Guide To Mechanical Rangeland Regeneration, J. Addison

Bulletins 4000 -

The main objective of this Bulletin is to describe mechanical methods of promoting rangeland regeneration and how to determine which is the most appropriate to use on any particular site. Mechanical regeneration methods are not 'quick fix' but may be used to advantage in some rangeland regeneration strategies.


Across-Column Cracks And Axial Splits In S2 Saline Ice Under Compression, E. M. Schulson, S. Qi, J. S. Melton, E. T. Gratz Feb 1997

Across-Column Cracks And Axial Splits In S2 Saline Ice Under Compression, E. M. Schulson, S. Qi, J. S. Melton, E. T. Gratz

Dartmouth Scholarship

Experiments on plate-like specimens have established that across-column cracks from within S2 (columnar) salt-water ice when compressed uniaxially along a direction inclined to the long axis of the grains. Wing cracks initiate from the across-column cracks and lengthen into axial splits when the ice is rapidly deformed; correspondingly; the macroscopic behavior changes from ductile to brittle. The across-column cracking is attributed to grain-boundary sliding, and the splitting to the suppression of crack-tip creep.


How Do Bacteria Move Through Soil?, Mark S. Coyne, J. M. Howell, R. E. Phillips Jan 1997

How Do Bacteria Move Through Soil?, Mark S. Coyne, J. M. Howell, R. E. Phillips

Soil Science News and Views

The contamination of water supplies by fecal bacteria is an important water quality issue in Kentucky. Contamination may come from point sources, such as straight pipes depositing raw sewage into streams, or nonpoint sources, such as manure runoff from cropland. A direct cost of contaminating water supplies is the expense that homesteads or water companies incur to chlorinate, filter, and otherwise treat water to make it potable. Indirect costs are the time lost to illness from drinking inadequately treated water, slower weight gain in livestock drinking contaminated water, and the degradation of aquatic habitats.


Late Cretaceous Dinosaurs In Eastern Usa—A Taphonomic And Biogeographic Model Of Occurrences., David R. Schwimmer Jan 1997

Late Cretaceous Dinosaurs In Eastern Usa—A Taphonomic And Biogeographic Model Of Occurrences., David R. Schwimmer

Faculty Bibliography

The eastern Coastal Plains of the USA contain a Late Cretaceous dinosaur assemblage of limited taxic diversity, but with wide distribution and reasonably good abundance. The ages of specimens range from Santonian through late Maastrichtian. All Late Cretaceous eastern dinosaur specimens occur in pericontinental or marine strata, and therefore all such fossils are likely to be allochthonous. New materials and insights bear on the taphonomy of these marine occurrences, suggesting that fluvially-transported, floating carcasses, many scavenged by sharks, make up most of the eastern marine dinosaur record. There is little evidence of faunal provinciality across the entire eastern outcrop: fossil …


The Selachian Genus Sqaulicorax As Preeminent Scavengers In Upper Cretaceous Marine Sediments Of North America, David R. Schwimmer Jan 1997

The Selachian Genus Sqaulicorax As Preeminent Scavengers In Upper Cretaceous Marine Sediments Of North America, David R. Schwimmer

Faculty Bibliography

No abstract provided.


Profitability Of Variable Rate Fertilization On A Kentucky Soil (A Theoretical Analysis), Lloyd W. Murdock, Paula L. Howe Jan 1997

Profitability Of Variable Rate Fertilization On A Kentucky Soil (A Theoretical Analysis), Lloyd W. Murdock, Paula L. Howe

Soil Science News and Views

Grid soil sampling and variable rate fertilizer applications are a part of the precision agriculture movement that has captured the interest of many farmers. Variable rate fertilization requires extra expense and effort plus the use of often unfamiliar technology. Global Positioning Systems (GPS) equipment and computer software are used to outline and grid the field into small manageable units or “cells” (usually 2.5 acres). Each grid cell is soil sampled and tested for pH and available nutrients. Fertilizer recommendations are made on each grid cell and the fertilizer is spread by each grid cell using a truck equipped with GPS …


Early Season Disease Control In Winter Cereals With Real ® Seed Dressing., R Loughman, J Hodgson Jan 1997

Early Season Disease Control In Winter Cereals With Real ® Seed Dressing., R Loughman, J Hodgson

Experimental Summaries - Plant Research

Establish a rate response for Real on powdery mildew (Erysiphe graminis) and determine crop safety of the formulation.

Chemicals applied as seed dressings prior to sowing. Completely randomized block design with four replicates.


Western Australia Soil Acidity Research And Development Update 1997 : Time To Lime, Department Of Agriculture And Food, Western Australia Jan 1997

Western Australia Soil Acidity Research And Development Update 1997 : Time To Lime, Department Of Agriculture And Food, Western Australia

Bulletins 4000 -

There is a lot of lime being spread in Western Australia – or is there?

In fact, the Australian Bureau of Statistics agricultural census paints a picture showing that we are still far short of the amount of lime that should be getting on to the ground.

For many years Western Australian soils acidified without significant production penalties. The soil pH was at values that were not affecting plant growth. However, over the last decade or so, large areas of soils have reached the point where production is being affected. In addition, we are now introducing plant species such as …


Jamaican Cave Vertebrates, Donald A. Mcfarlane Jan 1997

Jamaican Cave Vertebrates, Donald A. Mcfarlane

WM Keck Science Faculty Papers

Limestone caves in the tropics are typically associated with a more diverse assemblage of vertebrates than are caves in temperate regions. Chapman [87] for example, has reported 37 species from the caves of Gunung Mulu National Park, Sarawak, whereas Bailey [43] lists only 13 for the equally cavernicolous Guadeloupe Mountains National Park, New Mexico, USA. Twenty-eight vertebrate species have been recorded from Jamaican caves. The relative importance of the five Classes differ in these three areas as shown in Table 1 (overleaf).


Old Growth Ponderosa Pine And Western Larch Stand Structures: Influences Of Pre-1900 Fires And Fire Exclusion, United States Department Of Agriculture, Forest Service Jan 1997

Old Growth Ponderosa Pine And Western Larch Stand Structures: Influences Of Pre-1900 Fires And Fire Exclusion, United States Department Of Agriculture, Forest Service

Forestry

Presents detailed age structure for two western larch stands that historically experienced frequent fires. Compares age structures of eleven ponderosa pine and western larch stands representing a broad range of sites that had frequent fires. Interprets causal factors possibly linked to variations in stand age structures.


Sem Analysis Of Quartz Sand Grain Surface Textures Indicates Alluvial/Colluvial Origin Of The Quaternary "Glacial" Boulder Clays At Huangshan (Yellow Mountain), East-Central China, P. E. Helland, Pei-Hua Huang, Robert F. Diffendal Jr. Jan 1997

Sem Analysis Of Quartz Sand Grain Surface Textures Indicates Alluvial/Colluvial Origin Of The Quaternary "Glacial" Boulder Clays At Huangshan (Yellow Mountain), East-Central China, P. E. Helland, Pei-Hua Huang, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

Geomorphic features and Pleistocene deposits on Huangshan have been attributed to glaciation. Recent reassessment questions this interpretation. As part of the reassessment, quartz sand grains from deposits identified as glacial boulder clays (till composed of boulders in a clay or silt matrix) were analyzed by scanning electron microscope for evidence of their sedimentary history. Surface textures found on the boulder-clay grains were compared with those on grains with known sedimentary histories including glacial, grus, colluvial, and alluvial grains. The analysis shows that the grains lack typical glacial textures. The surface textures present indicate a complex history. Non-uniformly weathered grain surfaces …


Geology And Ground Water, Cheyenne County, Nebraska, Robert F. Diffendal Jr. Jan 1997

Geology And Ground Water, Cheyenne County, Nebraska, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The oldest rock unit exposed in Cheyenne County is the upper part of the Brule Formation, which is the youngest formation of the White River Group of the Oligocene epoch (33-29 million years old). Surface outcrops, road cuts, and railroad cuts through the Brule Formation occur along the sides of valleys along Lodgepole Creek from just east of Sidney westward to the vicinity of Brownson, along the valley sides of Sidney Draw and its tributaries, and along the sides of an unnamed drainageway northwest of Colton. Test drilling and drilling for wells along the floor of Lodgepole Creek have revealed …


Surface Textural Analysis Of Quartz Sand Grains From Odp Site 918 Off The Southeast Coast Of Greenland Suggests Glaciation Of Southern Greenland At 11 Ma, P. E. Helland, Mary Anne Holmes Jan 1997

Surface Textural Analysis Of Quartz Sand Grains From Odp Site 918 Off The Southeast Coast Of Greenland Suggests Glaciation Of Southern Greenland At 11 Ma, P. E. Helland, Mary Anne Holmes

Department of Earth and Atmospheric Sciences: Faculty Publications

Shipboard analysis of the 1,183-m sedimentary section recovered at Site 918 in the Irminger Basin during Ocean Drilling Program Leg 152 revealed material of glacial origin (diamictons, ice-rafted debris (IRD) and dropstones) as deep as 543 m below sea floor (bsf). The sediment containing the deepest dropstone was biostratigraphically dated shipboard as approximately 7 Ma, pushing back the date for the onset of glaciation on southern Greenland by 5 Ma. Thin layers of fine sand were found as much as 60 m deeper in the core, raising the possibility of an even earlier date for glaciation. To determine the sedimentary …


The Characterization Of An Amiid Species From The Fort Union Rock Formation Of The Early Paleocene, Alexis Penot Jan 1997

The Characterization Of An Amiid Species From The Fort Union Rock Formation Of The Early Paleocene, Alexis Penot

Honors Capstone Projects and Theses

No abstract provided.


Factors Affecting Atrazine Fate In North Central U.S. Soils, W. C. Koskinen, Sharon Clay Jan 1997

Factors Affecting Atrazine Fate In North Central U.S. Soils, W. C. Koskinen, Sharon Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Atrazine (6-chloro-N-ethyl-N′-(l-methylethyl)-l,3,5-triazine-2,4-diamine) is a herbicide of the triazine family used for controlling broadleaf and some grassy weeds in corn and sorghum. Since its introduction in the late 1950s, atrazine has been a popular herbicide because it is relatively inexpensive and, in most cases, gives good season-long weed control. It can be applied pre-or postemergence and is often tank mixed with grass herbicides, such as alachlor (2-chloro-N-(2,6-diethylphenyl-N-(methoxymethyl)acetamide), metolachlor(2-chloro-N-(2-2ethyl-6-methylphenyl)-N-(2-methoxy-l-methylethyl) acetamide), butylate (S-ethyl bis(2-methylpropyl)carbamothioate), or EPTC (S-ethyl dipropylcarbamothioate), or with other broadleaf herbicides, such as dicamba (3,6-dichloro-2-methoxybenzoic …


The Salinity And Hydrology Of The Tambellup Townsite And Jam Creek Catchment, R Ferdowsian, A T. Ryder Jan 1997

The Salinity And Hydrology Of The Tambellup Townsite And Jam Creek Catchment, R Ferdowsian, A T. Ryder

Resource management technical reports

The study area covers the Tambellup Town and the Jam Creek Catchment (top photograph on cover). The Tambellup Town is located 115 km north of Albany. The town has a population of 360 people (800 in the whole Shire). Tambellup is experiencing increasing salinity problems. Saline groundwater levels are close to the soil surface and cause deterioration of buildings, roads, infrastructure, death of trees and scalding of land including the sporting grounds. Many hectares of land in the Jam Creek Catchment has become salt-affected and salinity is on increase. The objective of this study was to define the present salinity …


Detection Of Nitrate-N And Triazine Herbicides In Groundwater And Surface Water Of An Agricultural Watershed In Western Kentucky, John Potts, Larry Reber Jan 1997

Detection Of Nitrate-N And Triazine Herbicides In Groundwater And Surface Water Of An Agricultural Watershed In Western Kentucky, John Potts, Larry Reber

Soil Science News and Views

The quality of water in Kentucky's agricultural watersheds has received considerable attention in recent years. The main concerns in com production areas usually center on content of nitrogen (N) from commercial fertilizer and triazines from herbicide applications in water. Although N can be found naturally in Kentucky soils, it can't supply all the N that com needs to produce optimum yields. Therefore, fertilizer N is added to ensure ample nutrition. Triazine herbicides, on the other hand, do not occur naturally in the soil but are applied to the soil to effectively control weeds. Most commonly, these herbicides are applied at …


Forest Resource Statistics For Northern Utah, 1993, United States Department Of Agriculture, Forest Service Jan 1997

Forest Resource Statistics For Northern Utah, 1993, United States Department Of Agriculture, Forest Service

Forestry

About 5.2 million acres, or 25 percent, of northern Utah is forested. Fifty-two percent of this forest area is capable of producing commercial wood products and is classified as timberland. Forty-eight percent is classified as woodland, primarily pinyon-juniper. The predominant forest types on the timberland are aspen, Douglas-fir, lodgepole pine, and spruce-fir. The National Forest System manages 70 percent of the timberland; 23 percent is under private ownership, and 7 percent is under other public ownership (local, State, and other Federal). Thirteen percent of the timberland is withdrawn from commercial timber production and is in a reserved status. Most reserved …


No Tillage Use For Crop Production In Kentucky Counties In 1996, Gerald R. Haszler, Grant W. Thomas Jan 1997

No Tillage Use For Crop Production In Kentucky Counties In 1996, Gerald R. Haszler, Grant W. Thomas

Soil Science News and Views

Two years ago, we reported the status of notillage adoption in Kentucky counties in the year 1994. Now, CTIC has published the results for 1996. As before, Kentucky leads the nation in percent of crops produced under no tillage, but the percentage has increased significantly. In 1994, 44% of crops were produced under no tillage in Kentucky, whereas in 1996, that figure had reached 51 %. The results for both 1994 and 1996 are shown in Table 1. It is evident that Kentucky has both maintained first place and has also increased its lead over the other states. The percentage …


Filter Strip Length And Fecal Bacteria Trapping From Poultry Waste - An Update, Mark S. Coyne, R. A. Gilfillen, Robert L. Blevins Jan 1997

Filter Strip Length And Fecal Bacteria Trapping From Poultry Waste - An Update, Mark S. Coyne, R. A. Gilfillen, Robert L. Blevins

Soil Science News and Views

Cheap, efficient, and environmentally sound waste disposal will be needed as Kentucky's broiler industry expands. The filter strip length needed to protect water resources from contaminants in surface runoff is a pressing issue in waste management and water quality. In a previous Soil Science News and Views (Vol. 15, No. 8) we reported that grass filter strips as short as 15 feet can trap over 90% of the fecal bacteria eroding from land-applied and incorporated poultry waste during runoff following rainstorms. In this update, we provide some additional information and conclusions from that study on filter strip length, based on …


Physical, Chemical, And Biological Data For Detailed Study Of Irrigation Drainage In The San Juan Area, New Mexico, 1993-94, With Supplemental Data, 1991-95, United States Geological Survey Jan 1997

Physical, Chemical, And Biological Data For Detailed Study Of Irrigation Drainage In The San Juan Area, New Mexico, 1993-94, With Supplemental Data, 1991-95, United States Geological Survey

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

Investigators collected water, bottom-sediment, soil, and biological samples at more than 50 sites in the San Juan River area during 1993-94. Sample sites included (1) sites located within Department of the Interior irrigation project service areas, or areas that receive drainage from irrigation projects; (2) reference sites for comparison with irrigation project sites; and (3) sites located within the reach of the San Juan River from Navajo Dam to 10 miles downstream from the dam.


Logging Utilization - Utah, 1993, United States Department Of Agriculture, Forest Service Jan 1997

Logging Utilization - Utah, 1993, United States Department Of Agriculture, Forest Service

Forestry

Data collected on 20 logging operations in Utah in 1993 provided board-foot and cubic-foot conversion factors of log scale and factors to apply to harvest volume estimates to obtain removals estimates. The components of timber products and removals, obtained by application of these factors to the 1992 Utah timber harvest, are included. Additional findings, presented in table form, are the diameter distribution of trees removed from growing stock per thousand cubic ft of products and the volume of logging residue in pieces 6 ft and longer as a proportion of product volume. Survey methods and estimates of data reliability are …


Utah Timber Production And Mill Residue, 1992, United States Department Of Agriculture, Forest Service Jan 1997

Utah Timber Production And Mill Residue, 1992, United States Department Of Agriculture, Forest Service

Forestry

Utah's timber production in 1992 was 13.3 million cubic feet (63.7 million board feet, Scribner rule), up 9 percent from 1974. Sawlog production was 10.2 million cubic feet (52.5 million board feet). House log volume was 1.6 million cubic feet (8.2 million board feet). Lodgepole pine comprised 48 percent, Uintah County 29 percent, and National Forest lands 78 percent of the harvest. Mill residue volume was 7 million cubic feet, 82 percent of which was used, most for fencing, firewood, animal bedding, or industrial plant fuel.


Fracture Permeability And Its Relationship To In-Situ Stress In The Dixie Valley, Nevada, Geothermal Reservoir, Colleen A. Barton, Stephen Hickman, Roger H. Morin, Mark D. Zoback, Thomas Finkbeiner, John Sass, Dick Benoit Jan 1997

Fracture Permeability And Its Relationship To In-Situ Stress In The Dixie Valley, Nevada, Geothermal Reservoir, Colleen A. Barton, Stephen Hickman, Roger H. Morin, Mark D. Zoback, Thomas Finkbeiner, John Sass, Dick Benoit

United States Geological Survey: Staff Publications

An extensive suite of spinner flowmeter, high-resolution temperature and borehole televiewer logs were acquired in a 2.7-km-deep well drilled into a fault-hosted geothermal reservoir at Dixie Valley, Nevada. Localized perturbations to wellbore temperature and flow were used to identify hydraulically conductive fractures. Comparison of these data with fracture orientations from the borehole televiewer logs indicates that hydraulically conductive fractures in crystalline rocks within and adjacent to the producing fault zone have an orientation distinct from the overall fracture population. In conjunction with in-situ stress measurements from this well, Coulomb analysis indicates that these permeable fractures are critically stressed, potentially active …


Soil Assessment Of The West Gingin Area, Henry Smolinski, G G. Scholz Jan 1997

Soil Assessment Of The West Gingin Area, Henry Smolinski, G G. Scholz

Land resources series

Soils of approximately 80,000 hectares in the West Gingin area, 100 km north of Perth, were surveyed from 1987 to 1989. The area lies on the Swan Coastal Plain within the Gingin Shire. The soils were mapped by the free survey method at a scale of 1:50,000. Thirty-five major soil associations and complexes were identified. These soils have been formed from various parent materials in a a range of depositional environments. Siliceous sand and sodic soils formed in alluvial-lacustrine sediments predominate. The main soils were sampled for chemical and physical analysis and their morphological, chemical and physical properties are discussed …


Catchments Of The Esperance Region Of Western Australia, S T. Gee, John Andrew Simons Jan 1997

Catchments Of The Esperance Region Of Western Australia, S T. Gee, John Andrew Simons

Resource management technical reports

This document provides a catalogue of the cultural and physical characteristics of the 32 catchments and internally drained areas in the Esperance agricultural region. Nineteen topographic catchments externally drain to the coast and the remaining 13 areas drain internally within their own boundaries.


Morilla Swamp Hydrological Investigation, Russell John Speed, E B. Lefroy, John Andrew Simons Jan 1997

Morilla Swamp Hydrological Investigation, Russell John Speed, E B. Lefroy, John Andrew Simons

Resource management technical reports

No abstract provided.


First Record Of Common Moorhen Nesting In South Dakota, William A. Meeks, Kenneth F. Higgins Jan 1997

First Record Of Common Moorhen Nesting In South Dakota, William A. Meeks, Kenneth F. Higgins

United States Geological Survey: Staff Publications

The common moorhen (Gallinula chloropus) is widespread in North America, but is not very abundant throughout its range (Greij 1994, Common Moorhen, Pages 145-157 in Tacha and Braun [eds.] Migratory Shore and Upland Game Bird Management in North America, Allen Press, Lawrence). In North Dakota its status is accidental (Konrad 1983, Prairie Nat. 15:144); in South Dakota it is considered a casual visitor and a probable breeding species (South Dakota Ornithologists' Union 1991, The Birds of South Dakota, Northern State University Press, Aberdeen; Peterson 1995, The Breeding Bird Atlas of South Dakota, Northern State University Press, Aberdeen).