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School of Natural Resources: Faculty Publications

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Articles 1441 - 1470 of 1586

Full-Text Articles in Physical Sciences and Mathematics

Morphometrics Of The Family Emballonuridae, Patricia W. Freeman, Cliff A. Lemen Sep 1992

Morphometrics Of The Family Emballonuridae, Patricia W. Freeman, Cliff A. Lemen

School of Natural Resources: Faculty Publications

Morphometric analysis revealed three distinctive groups among the genera of emballonurids. Taphozous-Saccolaimus is a group distinctive in size and shape, particularly cranially. Diclidurids are distinctive in appendicular characters only, especially those in the wing. The third group include all other emballonurids. Phylogenetic studies also separated Taphozous-Saccolaimus as distinctive but included diclidurids among other New World species. Compared with molossids, emballonurids are morphometrically quite homogeneous.

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Synthetic-Aperture Radar Imagery And Digital Shaded-Relief Map Of Northwest Nebraska: Probable Structures And Geomorphic Features Of The Region, Robert F. Diffendal Jr. Apr 1992

Synthetic-Aperture Radar Imagery And Digital Shaded-Relief Map Of Northwest Nebraska: Probable Structures And Geomorphic Features Of The Region, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

In 1988 the United States Geological Survey published a radar image mosaic of an area roughly that of the Alliance. Nebraska 1° × 2° topographic map at the same scale, 1:250,000. Striking near-parallel valley trends in the vicinity of Chadron, Nebraska, may be related to jointing or possible faulting. Two sets, oriented approximately N30E and N28W, are obvious in the area east of Chadron. Sets south of Chadron on the Pine Ridge trend approximately N40E and N50W. On the Pine Ridge west of Fort Robinson in Sioux County some E-W and N-S features are also apparent. Other features that may …

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Survey Of Mollusks Of The Platte River: Final Report, Patricia W. Freeman, Keith Perkins Mar 1992

Survey Of Mollusks Of The Platte River: Final Report, Patricia W. Freeman, Keith Perkins

School of Natural Resources: Faculty Publications

A survey of the mollusks of the Platte River was carried out during the summers of 1990 and 1991. With the exception of the Big Bend Reach of the River in Dawson, Buffalo and Hall counties, no unionids (mussels) were found in the main channel of the river. We found 11 species of mussels along the river and 16 species of snails at 49 different sites from east to west across the state. We found the Asiatic clam, a known, non-native, pest species, for the first time in the state placing it several hundred miles west of the present eastern …

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Coprolite Analysis: A Biological Perspective On Archaeology, Karl J. Reinhard, Vaughn M. Bryant Jr. Feb 1992

Coprolite Analysis: A Biological Perspective On Archaeology, Karl J. Reinhard, Vaughn M. Bryant Jr.

School of Natural Resources: Faculty Publications

The most remarkable dietary remains recoverable from archaeological contexts are coprolites. Coprolites are desiccated or mineralized feces that are preserved in sheltered and open sites in arid regions, primarily in the New World. These dietary remains are remarkable from several perspectives. They typically contain a variety of macroscopic and microscopic remains that form interrelated data sets for the reconstruction of diets. Because contexts containing coprolites are typified by excellent preservation, the remains coprolites contain tend to be in better states of preservation than dietary remains recovered from nonfecal deposits. Coprolites also contain the well-preserved remains of intestinal parasites and pathogens …

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Nonfederal Automated Weather Stations And Networks In The United States And Canada: A Preliminary Survey*, Steven J. Meyer, Kenneth G. Hubbard Jan 1992

Nonfederal Automated Weather Stations And Networks In The United States And Canada: A Preliminary Survey*, Steven J. Meyer, Kenneth G. Hubbard

School of Natural Resources: Faculty Publications

Not all weather data are collected by federal agencies. Fueled by the need for more specific meteorological data in real or near-real-time, the number of automated weather stations (AWSs) and AWS networks has expanded to the state and private sector over the past decade. This study employed a survey to determine the spatial extent and disposition of these nonfederal AWSs and AWS networks in the United States and Canada, the type of measurements taken, the operating procedures (i.e., maintenance and data-retrieval techniques), and the uses of the data (e.g., research, public service, agency needs). The rapid growth and expansion in …

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Opportunities To Increase Tree Planting In Shelterbelts And The Potential Impacts On Carbon Storage And Conservation, James R. Brandle Jan 1992

Opportunities To Increase Tree Planting In Shelterbelts And The Potential Impacts On Carbon Storage And Conservation, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

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Why Can The Weighting Parameter Of The Muskingum Channel Routing Method Be Negative?, Jozsef Szilagyi Jan 1992

Why Can The Weighting Parameter Of The Muskingum Channel Routing Method Be Negative?, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

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Atmospheric Effects On The Ndvi--Strategies For Its Removal, Y. J. Kaufman, D. Tanré, B. N. Holben, B. L. Markham, Anatoly A. Gitelson Jan 1992

Atmospheric Effects On The Ndvi--Strategies For Its Removal, Y. J. Kaufman, D. Tanré, B. N. Holben, B. L. Markham, Anatoly A. Gitelson

School of Natural Resources: Faculty Publications

The compositing technique used to derive global vegetation index (NDVI) from the NOAA-AVHRR radiances, reduces the residual effect of water vapor and aerosol on the NDVI. The reduction in the atmospheric effect is shown using a comprehensive measured data set for desert conditions, and a simulation for grass with continental aerosol. A statistical analysis of the probability of occurrence of aerosol optical thickness and precipitable water vapor measured in different climatic regimes is used for this simulation. It is concluded that for a long compositing period (e.g. 27 day), the residual aerosol optical thickness and precipitable water vapor is usually …

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Ectoparasitism As A Cause Of Natal Dispersal In Cliff Swallows, Charles R. Brown, Mary Bomberger Brown Jan 1992

Ectoparasitism As A Cause Of Natal Dispersal In Cliff Swallows, Charles R. Brown, Mary Bomberger Brown

School of Natural Resources: Faculty Publications

Nestling Cliff Swallows (Hirundo pyrrhonota) in southwestern Nebraska that were relatively heavily parasitized by hematophagous fleas (Ceratophyllus celsus) and swallow bugs (Oeciacus vicarius) dispersed to nonnatal colonies to breed the subsequent year, whereas nestlings that were relatively lightly parasitized returned to their natal colony to breed. There were no significant differences between dispersers and nondispersers in natal clutch size, natal brood size, relative hatching date, natal body mass, natal nest's distance from the colony's center, and natal nest's age. There were no sex differences in dispersal tendencies. Dispersing birds tended to move to smaller colonies …

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Scanning Electron Microscopic Study Of Quartz Sand Surface Features, Ash Hollow Formation, Ogallala Group, Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr. Apr 1991

Scanning Electron Microscopic Study Of Quartz Sand Surface Features, Ash Hollow Formation, Ogallala Group, Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

In field studies of the late Tertiary Ash Hollow Formation of the Ogallala Group in western Nebraska the alluvial deposits are composed of large volumes of sand and gravel up to large cobbles. Because the current understanding of the climate of the region at the time of deposition does not provide for a source for deposits of this character, a scanning electron microscopic study of the surface features on the quartz sand grains from these sediments was undertaken. Nine samples, collected from locations in Banner, Morrill and Keith Counties, were examined to see if they had one or more of …

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Plate Tectonics, Space, Geologic Time, And The Great Plains: A Primer For Non-Geologists, Robert F. Diffendal Jr. Apr 1991

Plate Tectonics, Space, Geologic Time, And The Great Plains: A Primer For Non-Geologists, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

For most Americans, "The Great Plains" evokes images of grasslands, dust storms, prairie fires, Native Americans on horseback, cowboys and wheat lands, and perhaps flat valleys crossed by braided rivers carrying a heavy load of sand and gravel, extremes of weather, and a climate typified by an alternation of droughts and wetter periods. Geologists picture such general images, too, but they also see radical changes in the landscape over periods expressed in millions rather than hundreds of years. Geologically speaking, human activities on the Great Plains are too recent to have much of a place in the broad geologic history …

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Late Paleozoic Cyclic Sedimentation In Southeastern Nebraska: A Field Guide, Roger K. Pabian, Robert F. Diffendal Jr. Apr 1991

Late Paleozoic Cyclic Sedimentation In Southeastern Nebraska: A Field Guide, Roger K. Pabian, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

People studying and collecting sedimentary rocks, minerals, and fossils in eastern Nebraska often find that locating rock exposures can be difficult. Most of the rolling hills in the eastern sixth of the state are underlain by thick, interlayered, glacial deposits, loess (windblown silt), and alluvium (stream-deposited sediments) of very young geologic age. These sediments cover the bedrock in most of that area. Natural exposures and human excavations of bedrock are mostly confined to the sides and floors of stream valleys. However, in the southeasternmost counties of the state, the younger sediment cover is commonly thin or absent. Pawnee and Richardson …

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Wbecon: A Windbreak Evaluation Model 1, James R. Brandle Jan 1991

Wbecon: A Windbreak Evaluation Model 1, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

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Estimation Of Shortwave Hemispherical Reflectance (Albedo) From Bidirectionally Reflected Radiance Data, Elizabeth A. Walter-Shea, Blaine L. Blad Jan 1991

Estimation Of Shortwave Hemispherical Reflectance (Albedo) From Bidirectionally Reflected Radiance Data, Elizabeth A. Walter-Shea, Blaine L. Blad

School of Natural Resources: Faculty Publications

No abstract provided.

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Leaf Reflectance And Transmittance In Soybean And Corn, Elizabeth A. Walter-Shea, Blaine Blad Jan 1991

Leaf Reflectance And Transmittance In Soybean And Corn, Elizabeth A. Walter-Shea, Blaine Blad

School of Natural Resources: Faculty Publications

No abstract provided.

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Predicting Canopy Light-Use Efficiency From Leaf Characteristics, T. J. Arkebauer Jan 1991

Predicting Canopy Light-Use Efficiency From Leaf Characteristics, T. J. Arkebauer

School of Natural Resources: Faculty Publications

No abstract provided.

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Modeling Canopy Stomatal Conductance In A Temperate Grassland Ecosystem, Joon Kim, Shashi B. Verma Jan 1991

Modeling Canopy Stomatal Conductance In A Temperate Grassland Ecosystem, Joon Kim, Shashi B. Verma

School of Natural Resources: Faculty Publications

No abstract provided.

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Modeling Canopy Photosynthesis: Scaling Up From A Leaf To Canopy In A Temperate Grassland Ecosystem, S. B. Verma Jan 1991

Modeling Canopy Photosynthesis: Scaling Up From A Leaf To Canopy In A Temperate Grassland Ecosystem, S. B. Verma

School of Natural Resources: Faculty Publications

No abstract provided.

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Photoperiod Control Of Poplar Bark Storage Protein Accumulation, Gary D. Coleman, Tony H.H. Chen, Stephen G. Ernst, Leslie Fuchigami Jan 1991

Photoperiod Control Of Poplar Bark Storage Protein Accumulation, Gary D. Coleman, Tony H.H. Chen, Stephen G. Ernst, Leslie Fuchigami

School of Natural Resources: Faculty Publications

Bark storage proteins (BSPs) accumulate in the inner bark parenchyma of many woody plants during autumn and winter. We investigated the effect of a short-day (SD) photoperiod on the accumulation of the 32-kilodalton bark storage protein of poplar (Populus deltoides Bart. ex Marsh.) under controlled environmental and natural growing conditions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and protein gel blot analysis revealed that 10 days of SD exposure (8 hours of light) resulted in a 20% increase in the relative abundance of the 32-kilodalton bark storage protein of poplar. After 17 days of SD exposure, the 32-kilodalton bark storage protein …

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Aerospace Monitoring Of Water Quality, Anatoly A. Gitelson, Ferenc Szilagyi Jan 1991

Aerospace Monitoring Of Water Quality, Anatoly A. Gitelson, Ferenc Szilagyi

School of Natural Resources: Faculty Publications

The potential of using remote sensing for the detection of chlorophyll-a (CHL), dissolved organic matter (DOM), and suspended matter (SM) concentrations in coastal and inland waters was investigated using measurements of (ir)radiance spectra along with simultaneous earth-reference data. The range of CHL was 0.1 to 350 μg/l, SM was 0.1 to 43 mg/l, and DOM absorption at the 380 nm was 0.1 to 10-1. Factor and signature analysis reveal allometric relationships between constituent concentrations C and functions of reflectance Zk of the type Ck = aZkb. Appropriate functions of R were found: Z …

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How Windbreaks Work, James R. Brandle, Sherman Finch Jan 1991

How Windbreaks Work, James R. Brandle, Sherman Finch

School of Natural Resources: Faculty Publications

Windbreaks are barriers used to reduce and redirect wind. They usually consist of trees and shrubs, but may also be perennial or annual crops and grasses, fences, or other materials. The reduction in wind speed behind a windbreak modifies the environmental conditions or microclimate in the sheltered zone.

As wind blows against a windbreak, air pressure builds up on the windward side (the side towards the wind), and large quantities of air move up and over the top or around the ends of the windbreak. Windbreak structure – height, density, number of rows, species, composition, length, orientation, and continuity – …

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Windbreak Establishment, Patricia Boehner, James R. Brandle, Sherman Finch Jan 1991

Windbreak Establishment, Patricia Boehner, James R. Brandle, Sherman Finch

School of Natural Resources: Faculty Publications

A successful windbreak planting depends on proper establishment and care during the first few years after planting. Time spent in site preparation, weed control, and replanting is repaid many times during the lifetime of the windbreak. Take no shortcuts in the planning and establishment of your windbreak.

Windbreaks are investments in the future value of your property. Each windbreak system is unique and your windbreak should be designed for your site and objectives. Your local conservation office can provide help in designing and installing your windbreak. These organizations can also help with recommendations on where to buy planting stock, and …

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Windbreaks And Wildlife, Ron J. Johnson, Mary M. Beck, James R. Brandle Jan 1991

Windbreaks And Wildlife, Ron J. Johnson, Mary M. Beck, James R. Brandle

School of Natural Resources: Faculty Publications

Windbreaks can support wildlife that add beauty and pleasure to our lives. They also sustain birds that eat insect pests, improve hunting opportunities, and provide a focal point for family outdoor activities. The world around us would be less appealing without the stimulation - the color, sounds, tracks, and mystery - of wild creatures; windbreaks help wildlife and in some areas are essential to survival of the wildlife we enjoy. You can add wildlife benefits to windbreak plantings whether your main goal is to shelter crops, livestock, + roads, or a home or farmstead.

This publication provides an overview of …

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Windbreaks In Sustainable Agricultural Systems, Vernon C. Quam, John Gardner, James R. Brandle, Teresa K. Boes Jan 1991

Windbreaks In Sustainable Agricultural Systems, Vernon C. Quam, John Gardner, James R. Brandle, Teresa K. Boes

School of Natural Resources: Faculty Publications

Sustainable agriculture is a system of whole-farm resource use balanced with whole-farm productivity. The overall level of productivity achieved is dependent upon the ability to coordinate and manage simultaneously the soil, water, plant, and animal resources within climatic and economic limits. Both the kind and amount of plants and animals supported by the system are important and play significant roles, both individually and collectively in maintaining a healthy farm environment. In the future, integrated systems will help reduce human impact on resources while providing sufficient supplies of high quality food and fiber.

Windbreaks provide protection for people, animals, buildings, crops, …

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The Pacific/ North American Teleconnection Pattern And United States Climate. Part I: Regional Temperature And Precipitation Associations, Daniel J. Leathers, Brent Yarnal, Michael A. Palecki Nov 1990

The Pacific/ North American Teleconnection Pattern And United States Climate. Part I: Regional Temperature And Precipitation Associations, Daniel J. Leathers, Brent Yarnal, Michael A. Palecki

School of Natural Resources: Faculty Publications

The Pacific/ North American (PNA) teleconnection index, a measure of the strength and phase of the PNA teleconnection pattern, is related to the variations of the surface climate of the United States from 1947 through 1982 for the autumn, winter, and spring months when the PNA is a main mode of Northern Hemisphere mid-tropospheric variability. The results demonstrate that the PNA index is highly correlated with both regional temperature and precipitation. The strongest, most extensive correlations between the index and temperature are observed in winter, but large areas of the country show important associations during the spring and autumn as …

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Regional Climate Centers: New Institutions For Climate Service And Climate- Impact Research, Stanley A. Changnon, Peter J. Lamb, Kenneth G. Hubbard Apr 1990

Regional Climate Centers: New Institutions For Climate Service And Climate- Impact Research, Stanley A. Changnon, Peter J. Lamb, Kenneth G. Hubbard

School of Natural Resources: Faculty Publications

In response to the need climate services at the local, state, and regional levels, a national network of regional climate centers has developed. This provides the background to this development, and outlines the functions of the centers and identifies their benefits and beneficiaries. The centers are a source of climate expertise and maintain multifaceted interfaces with the public and private sectors. Each center a) performs services, including the management of the basic data for its region and the delivery of specialized products; b) conducts applied climate studies, including the monitoring of anomalous conditions and the promotin of regional research; and …

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Potential Effects Of Climate Change On Tree Survival And Forest Pests In The Great Plains, James R. Brandle Jan 1990

Potential Effects Of Climate Change On Tree Survival And Forest Pests In The Great Plains, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

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Potential Effects Of Climate Change On Tree Survival And Forest Pests In The Great Plains, James R. Brandle Jan 1990

Potential Effects Of Climate Change On Tree Survival And Forest Pests In The Great Plains, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

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Shelterbelts: A Buffer To Climate On The Plains, James R. Brandle Jan 1990

Shelterbelts: A Buffer To Climate On The Plains, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

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Management Of Microclimate With Windbreaks, James R. Brandle Jan 1990

Management Of Microclimate With Windbreaks, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

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